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A novel mutation in MBTPS2 causes a broad phenotypic spectrum of ichthyosis follicularis, atrichia, and photophobia syndrome in a large Chinese family. BACKGROUND: Ichthyosis follicularis, atrichia, and photophobia (IFAP) syndrome is a rare congenital disorder. Missense mutations in the membrane-bound transcription factor protease, site 2 (MBTPS2) gene have recently been identified in patients with IFAP. OBJECTIVE: To determine whether Chinese patients with IFAP have MBTPS2 mutations. METHODS: We observed a large IFAP pedigree of 5 generations in a Chinese family and performed MBTPS2 molecular analysis. RESULTS: The male proband was severely affected. He presented with hyperextensibility of the interphalangeal joints of the fingers in addition to previously reported clinical manifestations. Clinically affected female patients had hairless patches on the scalp, ichthyosiform skin changes, hypotrichosis, hyperkeratosis, nail dystrophy, and brown scaly plaques, some of which were arranged in a linear pattern following the lines of Blaschko. Molecular analysis identified a novel missense mutation in exon 11 and confirmed cosegregation of the missense mutation with the disease in this family. LIMITATIONS: It is unclear whether hyperextensibility of the fingers was nosologically related to IFAP syndrome or was a coincidental finding. CONCLUSION: This report provides further evidence for the genetic basis of IFAP syndrome and enlarges the phenotypic spectrum and number of MBTPS2 mutations. We confirm that MBTPS2 mutations cause IFAP in patients of Chinese origin.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_020

Ichthyosis follicularis with atrichia and photophobia (IFAP) syndrome in two unrelated female patients. The IFAP syndrome is characterized by the congenital onset of ichthyosis follicularis, absence of hair, and photophobia. A limited number of patients with the disorder have been described, and X-linked recessive inheritance has been proposed. Two unrelated female patients with a complete IFAP syndrome are reported. Both patients show a diffuse distribution of the disorder without linear arrangement. Because the suggested X-linked recessive pattern of inheritance is unlikely in these patients, a different way of transmission or, alternatively, genetic heterogeneity of the disorder has to be considered.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_021

Ichthyosis follicularis with atrichia and photophobia (IFAP) syndrome in two unrelated female patients. The IFAP syndrome is characterized by the congenital onset of ichthyosis follicularis, absence of hair, and photophobia. A limited number of patients with the disorder have been described, and X-linked recessive inheritance has been proposed. Two unrelated female patients with a complete IFAP syndrome are reported. Both patients show a diffuse distribution of the disorder without linear arrangement. Because the suggested X-linked recessive pattern of inheritance is unlikely in these patients, a different way of transmission or, alternatively, genetic heterogeneity of the disorder has to be considered.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_022

Linear lesions reflecting lyonization in women heterozygous for IFAP syndrome (ichthyosis follicularis with atrichia and photophobia). A diagnosis of IFAP (ichthyosis follicularis with atrichia and photophobia) syndrome was established in a 1-year-old boy with congenital hairlessness, generalized ichthyotic skin changes with follicular hyperkeratoses, and photophobia. IFAP syndrome is considered to be an X-linked recessive trait. The phenotype present in female carriers has so far not been delineated. A 2-year-old sister had atrophoderma and ichthyotic skin lesions arranged in a linear pattern and a large noncicatrical bald patch on her scalp. Similarly, the mother had linear lesions of scaling and atrophy as well as circumscribed hairless areas involving the scalp, the axillary region, and the lower legs. Sweat testing by means of iodine starch-reaction visualized hypohidrotic linear lesions corresponding to the areas of hyperkeratosis and atrophy. In both mother and daughter the lesions followed the lines of Blaschko, whereas the boy was diffusely affected. Family history showed that the boy's maternal uncle who had died at age 1 year was likewise affected with the same disorder. Moreover, the maternal grandmother had reportedly bald patches on her scalp and very dry skin. This is the first report to document linear skin lesions visualizing lyonization in women heterozygous for IFAP syndrome.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_023

Linear lesions reflecting lyonization in women heterozygous for IFAP syndrome (ichthyosis follicularis with atrichia and photophobia). A diagnosis of IFAP (ichthyosis follicularis with atrichia and photophobia) syndrome was established in a 1-year-old boy with congenital hairlessness, generalized ichthyotic skin changes with follicular hyperkeratoses, and photophobia. IFAP syndrome is considered to be an X-linked recessive trait. The phenotype present in female carriers has so far not been delineated. A 2-year-old sister had atrophoderma and ichthyotic skin lesions arranged in a linear pattern and a large noncicatrical bald patch on her scalp. Similarly, the mother had linear lesions of scaling and atrophy as well as circumscribed hairless areas involving the scalp, the axillary region, and the lower legs. Sweat testing by means of iodine starch-reaction visualized hypohidrotic linear lesions corresponding to the areas of hyperkeratosis and atrophy. In both mother and daughter the lesions followed the lines of Blaschko, whereas the boy was diffusely affected. Family history showed that the boy's maternal uncle who had died at age 1 year was likewise affected with the same disorder. Moreover, the maternal grandmother had reportedly bald patches on her scalp and very dry skin. This is the first report to document linear skin lesions visualizing lyonization in women heterozygous for IFAP syndrome.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_024

Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome due to mutation of the gene MBTPS2 in a large Australian kindred. Ichthyosis follicularis, alopecia and photophobia (IFAP) is a rare genodermatosis. Most patients have been men without significant family history. We present the largest kindred of IFAP reported to date in the medical literature clearly demonstrating X-linked inheritance. The gene defect has recently been mapped to Xp22.11-p22.13. Missense mutations of the gene, MBTPS2, which codes for an intramembrane zinc metalloprotease essential for cholesterol homeostasis and endoplasmic reticulum stress response, are associated with the IFAP phenotype in this kindred. We describe the clinical features and discuss the differential diagnosis of IFAP. Our proband has benefited from treatment with acitretin.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_025

Ichthyosis follicularis, alopecia and photophobia (IFAP) syndrome treated with acitretin. We describe a 3-year-old male patient with the ichthyosis follicularis, alopecia and photophobia (IFAP) syndrome, who developed cutaneous and ocular involvement in infancy. In addition, he had growth retardation and borderline intelligence; no other systemic involvement was found on detailed investigation. A moderate response to acitretin therapy (1 mg/kg) administered for 6 months was observed, with improvement in cutaneous features and corneal erosions and no change in alopecia or photophobia.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_026

Atrichia, ichthyosis, follicular hyperkeratosis, chronic candidiasis, keratitis, seizures, mental retardation and inguinal hernia: a severe manifestation of IFAP syndrome? A boy with congenital atrichia, ichthyosis follicular, keratitis, cutaneous infections and a huge inguinal hernia, but without deafness is reported. We believe it represents a new case of a rare X-linked recessive syndrome known as ichthyosis follicularis, alopecia, photophobia syndrome (IFAP). The differential diagnosis from keratitis ichthyosis deafness is discussed. The cutaneous infections seen in our case suggest the possibility of considering a genetic link between these syndromes.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_027

Ocular findings in ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome. PURPOSE: To report the ocular findings in two siblings with IFAP and their mother and to review the natural course of the keratopathy of this disease. METHODS: Clinical ophthalmological examination of all patients and fundus photography of the carrier mother were performed. RESULTS: Both affected male children had severe photophobia, total superficial and deep corneal vascularization, and reduction of vision to counting fingers.The mother had tortuous retinal vessels. CONCLUSIONS: Males with IFAP have an inexorable progression of corneal vascularization and loss of vision. Retinal vascular tortuosity may be another clinical sign of carrier status in females.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_028

Further delineation of the ichthyosis follicularis, atrichia, and photophobia syndrome. We describe an 18-month-old male infant suffering from the ichthyosis follicularis, atrichia, and photophobia (IFAP) syndrome and further delineate the clinical phenotype. Severe retardation of growth and psychomotor development, chill-like seizures, bronchial asthma, urticaria, a proneness to skin infections and transient nail dystrophy observed in our patient are non-obligatory manifestations of this disorder. Histological examination of the atrichia revealed poorly developed, shortened hair follicles and a complete absence of sebaceous glands. The sex ratio of published cases suggests an X-linked recessive inheritance. The marked clinical variability of the IFAP syndrome might be the expression of a contiguous gene defect.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_029

Further delineation of the ichthyosis follicularis, atrichia, and photophobia syndrome. We describe an 18-month-old male infant suffering from the ichthyosis follicularis, atrichia, and photophobia (IFAP) syndrome and further delineate the clinical phenotype. Severe retardation of growth and psychomotor development, chill-like seizures, bronchial asthma, urticaria, a proneness to skin infections and transient nail dystrophy observed in our patient are non-obligatory manifestations of this disorder. Histological examination of the atrichia revealed poorly developed, shortened hair follicles and a complete absence of sebaceous glands. The sex ratio of published cases suggests an X-linked recessive inheritance. The marked clinical variability of the IFAP syndrome might be the expression of a contiguous gene defect.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_030

Child with manifestations of dermotrichic syndrome and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome. We report on a boy with short stature, mental retardation, seizures, follicular ichthyosis, generalized alopecia, hypohydrosis, enamel dysplasia, photophobia, congenital aganglionic megacolon, inguinal hernia, vertebral, renal and other anomalies, and a normal chromosome constitution. The clinical findings include all the features that dermotrichic and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome have in common and in addition those that characterize IFAP syndrome (photophobia, recurrent respiratory infections, etc.), those that are present only in dermotrichic syndrome (nail anomalies, hypohydrosis, megacolon, vertebral defects, etc.) and additional ones (enamel dysplasia, renal anomalies, inguinal hernia, etc.). Two maternal uncles were referred as being affected by alopecia and ichthyosis suggesting X-linked recessive transmission. Various hypotheses concerning the relationship between the 2 syndromes and the present case are discussed.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_031

Child with manifestations of dermotrichic syndrome and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome. We report on a boy with short stature, mental retardation, seizures, follicular ichthyosis, generalized alopecia, hypohydrosis, enamel dysplasia, photophobia, congenital aganglionic megacolon, inguinal hernia, vertebral, renal and other anomalies, and a normal chromosome constitution. The clinical findings include all the features that dermotrichic and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome have in common and in addition those that characterize IFAP syndrome (photophobia, recurrent respiratory infections, etc.), those that are present only in dermotrichic syndrome (nail anomalies, hypohydrosis, megacolon, vertebral defects, etc.) and additional ones (enamel dysplasia, renal anomalies, inguinal hernia, etc.). Two maternal uncles were referred as being affected by alopecia and ichthyosis suggesting X-linked recessive transmission. Various hypotheses concerning the relationship between the 2 syndromes and the present case are discussed.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_032

Child with manifestations of dermotrichic syndrome and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome. We report on a boy with short stature, mental retardation, seizures, follicular ichthyosis, generalized alopecia, hypohydrosis, enamel dysplasia, photophobia, congenital aganglionic megacolon, inguinal hernia, vertebral, renal and other anomalies, and a normal chromosome constitution. The clinical findings include all the features that dermotrichic and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome have in common and in addition those that characterize IFAP syndrome (photophobia, recurrent respiratory infections, etc.), those that are present only in dermotrichic syndrome (nail anomalies, hypohydrosis, megacolon, vertebral defects, etc.) and additional ones (enamel dysplasia, renal anomalies, inguinal hernia, etc.). Two maternal uncles were referred as being affected by alopecia and ichthyosis suggesting X-linked recessive transmission. Various hypotheses concerning the relationship between the 2 syndromes and the present case are discussed.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_033

Child with manifestations of dermotrichic syndrome and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome. We report on a boy with short stature, mental retardation, seizures, follicular ichthyosis, generalized alopecia, hypohydrosis, enamel dysplasia, photophobia, congenital aganglionic megacolon, inguinal hernia, vertebral, renal and other anomalies, and a normal chromosome constitution. The clinical findings include all the features that dermotrichic and ichthyosis follicularis-alopecia-photophobia (IFAP) syndrome have in common and in addition those that characterize IFAP syndrome (photophobia, recurrent respiratory infections, etc.), those that are present only in dermotrichic syndrome (nail anomalies, hypohydrosis, megacolon, vertebral defects, etc.) and additional ones (enamel dysplasia, renal anomalies, inguinal hernia, etc.). Two maternal uncles were referred as being affected by alopecia and ichthyosis suggesting X-linked recessive transmission. Various hypotheses concerning the relationship between the 2 syndromes and the present case are discussed.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_034

Ocular findings in ichthyosis follicularis, atrichia, and photophobia syndrome. Ichthyosis follicularis, atrichia, and photophobia (IFAP) are typical features of a rare neuroichthyosis termed IFAP syndrome. We demonstrate the ultrastructural findings of the eyes from a 33-year-old patient with IFAP syndrome. Clinically, eyebrows and eyelashes were absent from birth, and photophobia was noted at the age of 1 year. The globes measured 28 and 29 mm, respectively, and both eyes showed a posterior staphyloma. Histopathologically, bilateral centrally located subepithelial avascular corneal scarring with secondary corneal amyloid deposition was found. In addition to already described ocular abnormalities in IFAP syndrome we demonstrate ultrastructural anomalies of desmosomes and tonofilaments in corneal epithelium; defects of basement membrane, Bowman layer, and anchoring fibrils; secondary corneal amyloid deposition; and keratocyte degeneration. A defective tear film, recurrent atopic keratoconjunctival inflammations, or a primary anomaly of corneal epithelial adhesion are potential causes for the corneal defects. Photophobia is most likely due to corneal abnormalities.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_035

Ocular findings in ichthyosis follicularis, atrichia, and photophobia syndrome. Ichthyosis follicularis, atrichia, and photophobia (IFAP) are typical features of a rare neuroichthyosis termed IFAP syndrome. We demonstrate the ultrastructural findings of the eyes from a 33-year-old patient with IFAP syndrome. Clinically, eyebrows and eyelashes were absent from birth, and photophobia was noted at the age of 1 year. The globes measured 28 and 29 mm, respectively, and both eyes showed a posterior staphyloma. Histopathologically, bilateral centrally located subepithelial avascular corneal scarring with secondary corneal amyloid deposition was found. In addition to already described ocular abnormalities in IFAP syndrome we demonstrate ultrastructural anomalies of desmosomes and tonofilaments in corneal epithelium; defects of basement membrane, Bowman layer, and anchoring fibrils; secondary corneal amyloid deposition; and keratocyte degeneration. A defective tear film, recurrent atopic keratoconjunctival inflammations, or a primary anomaly of corneal epithelial adhesion are potential causes for the corneal defects. Photophobia is most likely due to corneal abnormalities.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_036

Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome: report of a new family with additional features and review. Two brothers with ichthyosis follicularis, noncicatricial universal alopecia, photophobia, hyerkeratotic psoriasis-like lesions, nails dystrophy, inguineal herniae, cryptorchidism, short stature, seizures, and psychomotor developmental delay are described. These features correspond to the ichthyosis follicularis, alopecia, photophobia (IFAP) syndrome. The youngest brother had in addition a bilateral absence of 4th fingers and camptodactyly, features never reported in patients with IFAP syndromes.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_037

A novel mutation in MBTPS2 causes a broad phenotypic spectrum of ichthyosis follicularis, atrichia, and photophobia syndrome in a large Chinese family. BACKGROUND: Ichthyosis follicularis, atrichia, and photophobia (IFAP) syndrome is a rare congenital disorder. Missense mutations in the membrane-bound transcription factor protease, site 2 (MBTPS2) gene have recently been identified in patients with IFAP. OBJECTIVE: To determine whether Chinese patients with IFAP have MBTPS2 mutations. METHODS: We observed a large IFAP pedigree of 5 generations in a Chinese family and performed MBTPS2 molecular analysis. RESULTS: The male proband was severely affected. He presented with hyperextensibility of the interphalangeal joints of the fingers in addition to previously reported clinical manifestations. Clinically affected female patients had hairless patches on the scalp, ichthyosiform skin changes, hypotrichosis, hyperkeratosis, nail dystrophy, and brown scaly plaques, some of which were arranged in a linear pattern following the lines of Blaschko. Molecular analysis identified a novel missense mutation in exon 11 and confirmed cosegregation of the missense mutation with the disease in this family. LIMITATIONS: It is unclear whether hyperextensibility of the fingers was nosologically related to IFAP syndrome or was a coincidental finding. CONCLUSION: This report provides further evidence for the genetic basis of IFAP syndrome and enlarges the phenotypic spectrum and number of MBTPS2 mutations. We confirm that MBTPS2 mutations cause IFAP in patients of Chinese origin.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_038

A novel mutation in MBTPS2 causes a broad phenotypic spectrum of ichthyosis follicularis, atrichia, and photophobia syndrome in a large Chinese family. BACKGROUND: Ichthyosis follicularis, atrichia, and photophobia (IFAP) syndrome is a rare congenital disorder. Missense mutations in the membrane-bound transcription factor protease, site 2 (MBTPS2) gene have recently been identified in patients with IFAP. OBJECTIVE: To determine whether Chinese patients with IFAP have MBTPS2 mutations. METHODS: We observed a large IFAP pedigree of 5 generations in a Chinese family and performed MBTPS2 molecular analysis. RESULTS: The male proband was severely affected. He presented with hyperextensibility of the interphalangeal joints of the fingers in addition to previously reported clinical manifestations. Clinically affected female patients had hairless patches on the scalp, ichthyosiform skin changes, hypotrichosis, hyperkeratosis, nail dystrophy, and brown scaly plaques, some of which were arranged in a linear pattern following the lines of Blaschko. Molecular analysis identified a novel missense mutation in exon 11 and confirmed cosegregation of the missense mutation with the disease in this family. LIMITATIONS: It is unclear whether hyperextensibility of the fingers was nosologically related to IFAP syndrome or was a coincidental finding. CONCLUSION: This report provides further evidence for the genetic basis of IFAP syndrome and enlarges the phenotypic spectrum and number of MBTPS2 mutations. We confirm that MBTPS2 mutations cause IFAP in patients of Chinese origin.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_039

Expanding the phenotype of IFAP/BRESECK syndrome: a new case with severe hypogammaglobulinemia. The ichthyosis follicular with atrichia and photophobia syndrome (IFAP) is a rare X-linked multiple congenital malformation syndrome. Some male patients have additional features including brain anomalies, intellectual disability, ectodermal dysplasia, skeletal deformities, ear or eye anomalies and kidney dysplasia/hypoplasia (BRESEK syndrome) sometimes associated with Hirschsprung disease and cleft palate or cryptorchidism (BRESHECK syndrome). We report a 5 months-old male patient with the p.R429H mutation in MBTPS2 protein, which has been reported to be associated with the most severe phenotype of patients with IFAP/BRESHECK syndrome. This patient presented with a severe IFAP/BRESHECK phenotype including ichthyosis follicular, atrichia, photophobia, brain anomalies, global developmental delay, Hirschsprung disease and kidney hypoplasia. Additional features not previously reported in IFAP syndrome, include severe hypogammaglobulinemia and congenital rectourethral fistula.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_040

Expanding the phenotype of IFAP/BRESECK syndrome: a new case with severe hypogammaglobulinemia. The ichthyosis follicular with atrichia and photophobia syndrome (IFAP) is a rare X-linked multiple congenital malformation syndrome. Some male patients have additional features including brain anomalies, intellectual disability, ectodermal dysplasia, skeletal deformities, ear or eye anomalies and kidney dysplasia/hypoplasia (BRESEK syndrome) sometimes associated with Hirschsprung disease and cleft palate or cryptorchidism (BRESHECK syndrome). We report a 5 months-old male patient with the p.R429H mutation in MBTPS2 protein, which has been reported to be associated with the most severe phenotype of patients with IFAP/BRESHECK syndrome. This patient presented with a severe IFAP/BRESHECK phenotype including ichthyosis follicular, atrichia, photophobia, brain anomalies, global developmental delay, Hirschsprung disease and kidney hypoplasia. Additional features not previously reported in IFAP syndrome, include severe hypogammaglobulinemia and congenital rectourethral fistula.

List symptoms of the IFAP syndrome.

56c1f038ef6e394741000051_041

Treatment with antibiotics that interfere with peptidoglycan biosynthesis inhibits chloroplast division in the desmid Closterium. Charophytes is a green algal group closely related to land plants. We investigated the effects of antibiotics that interfere with peptidoglycan biosynthesis on chloroplast division in the desmid Closterium peracerosum-strigosum-littorale complex. To detect cells just after division, we used colchicine, which inhibits Closterium cell elongation after division. Although normal Closterium cells had two chloroplasts before and after cell division, cells treated with ampicillin, D-cycloserine, or fosfomycin had only one chloroplast after cell division, suggesting that the cells divided without chloroplast division. The antibiotics bacitracin and vancomycin showed no obvious effect. Electron microscopic observation showed that irregular-shaped chloroplasts existed in ampicillin-treated Closterium cells. Because antibiotic treatments resulted in the appearance of long cells with irregular chloroplasts and cell death, we counted cell types in the culture. The results suggested that cells with one chloroplast appeared first and then a huge chloroplast was generated that inhibited cell division, causing elongation followed by cell death.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_001

Treatment with antibiotics that interfere with peptidoglycan biosynthesis inhibits chloroplast division in the desmid Closterium. Charophytes is a green algal group closely related to land plants. We investigated the effects of antibiotics that interfere with peptidoglycan biosynthesis on chloroplast division in the desmid Closterium peracerosum-strigosum-littorale complex. To detect cells just after division, we used colchicine, which inhibits Closterium cell elongation after division. Although normal Closterium cells had two chloroplasts before and after cell division, cells treated with ampicillin, D-cycloserine, or fosfomycin had only one chloroplast after cell division, suggesting that the cells divided without chloroplast division. The antibiotics bacitracin and vancomycin showed no obvious effect. Electron microscopic observation showed that irregular-shaped chloroplasts existed in ampicillin-treated Closterium cells. Because antibiotic treatments resulted in the appearance of long cells with irregular chloroplasts and cell death, we counted cell types in the culture. The results suggested that cells with one chloroplast appeared first and then a huge chloroplast was generated that inhibited cell division, causing elongation followed by cell death.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_002

Treatment with antibiotics that interfere with peptidoglycan biosynthesis inhibits chloroplast division in the desmid Closterium. Charophytes is a green algal group closely related to land plants. We investigated the effects of antibiotics that interfere with peptidoglycan biosynthesis on chloroplast division in the desmid Closterium peracerosum-strigosum-littorale complex. To detect cells just after division, we used colchicine, which inhibits Closterium cell elongation after division. Although normal Closterium cells had two chloroplasts before and after cell division, cells treated with ampicillin, D-cycloserine, or fosfomycin had only one chloroplast after cell division, suggesting that the cells divided without chloroplast division. The antibiotics bacitracin and vancomycin showed no obvious effect. Electron microscopic observation showed that irregular-shaped chloroplasts existed in ampicillin-treated Closterium cells. Because antibiotic treatments resulted in the appearance of long cells with irregular chloroplasts and cell death, we counted cell types in the culture. The results suggested that cells with one chloroplast appeared first and then a huge chloroplast was generated that inhibited cell division, causing elongation followed by cell death.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_003

Treatment with antibiotics that interfere with peptidoglycan biosynthesis inhibits chloroplast division in the desmid Closterium. Charophytes is a green algal group closely related to land plants. We investigated the effects of antibiotics that interfere with peptidoglycan biosynthesis on chloroplast division in the desmid Closterium peracerosum-strigosum-littorale complex. To detect cells just after division, we used colchicine, which inhibits Closterium cell elongation after division. Although normal Closterium cells had two chloroplasts before and after cell division, cells treated with ampicillin, D-cycloserine, or fosfomycin had only one chloroplast after cell division, suggesting that the cells divided without chloroplast division. The antibiotics bacitracin and vancomycin showed no obvious effect. Electron microscopic observation showed that irregular-shaped chloroplasts existed in ampicillin-treated Closterium cells. Because antibiotic treatments resulted in the appearance of long cells with irregular chloroplasts and cell death, we counted cell types in the culture. The results suggested that cells with one chloroplast appeared first and then a huge chloroplast was generated that inhibited cell division, causing elongation followed by cell death.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_004

Treatment with antibiotics that interfere with peptidoglycan biosynthesis inhibits chloroplast division in the desmid Closterium. Charophytes is a green algal group closely related to land plants. We investigated the effects of antibiotics that interfere with peptidoglycan biosynthesis on chloroplast division in the desmid Closterium peracerosum-strigosum-littorale complex. To detect cells just after division, we used colchicine, which inhibits Closterium cell elongation after division. Although normal Closterium cells had two chloroplasts before and after cell division, cells treated with ampicillin, D-cycloserine, or fosfomycin had only one chloroplast after cell division, suggesting that the cells divided without chloroplast division. The antibiotics bacitracin and vancomycin showed no obvious effect. Electron microscopic observation showed that irregular-shaped chloroplasts existed in ampicillin-treated Closterium cells. Because antibiotic treatments resulted in the appearance of long cells with irregular chloroplasts and cell death, we counted cell types in the culture. The results suggested that cells with one chloroplast appeared first and then a huge chloroplast was generated that inhibited cell division, causing elongation followed by cell death.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_005

Treatment with antibiotics that interfere with peptidoglycan biosynthesis inhibits chloroplast division in the desmid Closterium. Charophytes is a green algal group closely related to land plants. We investigated the effects of antibiotics that interfere with peptidoglycan biosynthesis on chloroplast division in the desmid Closterium peracerosum-strigosum-littorale complex. To detect cells just after division, we used colchicine, which inhibits Closterium cell elongation after division. Although normal Closterium cells had two chloroplasts before and after cell division, cells treated with ampicillin, D-cycloserine, or fosfomycin had only one chloroplast after cell division, suggesting that the cells divided without chloroplast division. The antibiotics bacitracin and vancomycin showed no obvious effect. Electron microscopic observation showed that irregular-shaped chloroplasts existed in ampicillin-treated Closterium cells. Because antibiotic treatments resulted in the appearance of long cells with irregular chloroplasts and cell death, we counted cell types in the culture. The results suggested that cells with one chloroplast appeared first and then a huge chloroplast was generated that inhibited cell division, causing elongation followed by cell death.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_006

A rapid in situ procedure for determination of bacterial susceptibility or resistance to antibiotics that inhibit peptidoglycan biosynthesis. BACKGROUND: Antibiotics which inhibit bacterial peptidoglycan biosynthesis are the most widely used in current clinical practice. Nevertheless, resistant strains increase dramatically, with serious economic impact and effects on public health, and are responsible for thousands of deaths each year. Critical clinical situations should benefit from a rapid procedure to evaluate the sensitivity or resistance to antibiotics that act at the cell wall. We have adapted a kit for rapid determination of bacterial DNA fragmentation, to assess cell wall integrity. RESULTS: Cells incubated with the antibiotic were embedded in an agarose microgel on a slide, incubated in an adapted lysis buffer, stained with a DNA fluorochrome, SYBR Gold and observed under fluorescence microscopy. The lysis affects the cells differentially, depending on the integrity of the wall. If the bacterium is susceptible to the antibiotic, the weakened cell wall is affected by the lysing solution so the nucleoid of DNA contained inside the bacterium is released and spread. Alternatively, if the bacterium is resistant to the antibiotic, it is practically unaffected by the lysis solution and does not liberate the nucleoid, retaining its normal morphological appearance. In an initial approach, the procedure accurately discriminates susceptible, intermediate and resistant strains of Escherichia coli to amoxicillin/clavulanic acid. When the bacteria came from an exponentially growing liquid culture, the effect on the cell wall of the β-lactam was evident much earlier that when they came from an agar plate. A dose-response experiment with an E. coli strain susceptible to ampicillin demonstrated a weak effect before the MIC dose. The cell wall damage was not homogenous among the different cells, but the level of damage increased as dose increased with a predominant degree of effect for each dose. A microgranular-fibrilar extracellular background was evident in gram-negative susceptible strains after β-lactam treatment. This material was digested by DNase I, hybridised with a specific whole genome probe, and so recognized as DNA fragments released by the bacteria. Finally, 46 clinical strains from eight gram-negative and four gram-positive species were evaluated blind for susceptibility or resistance to one of four different β-lactams and vancomycin, confirming the applicability of the methodology. CONCLUSION: The technique to assess cell wall integrity appears to be a rapid and simple procedure to identify resistant and susceptible strains to antibiotics that interfere with peptidoglycan biosynthesis.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_007

Microtiter plate bioassay to monitor the interference of antibiotics with the lipid II cycle essential for peptidoglycan biosynthesis. Specific drug-sensing systems that coordinate appropriate genetic responses assure the survival of microorganisms in the presence of antibiotics. We report on the development and application of a microtiter plate-based bioassay for the identification of antibiotics interfering with the lipid II cycle essential for peptidoglycan biosynthesis. A Bacillus subtilis reporter strain sensing specifically lipid II - interfering cell wall biosynthesis stress (T. Mascher, S.L. Zimmer, T.-A. Smith and J. Helmann, Antibiotic-inducible promoter regulated by the cell envelope stress-sensing two-component system LiaRS of Bacillus subtilis; Antimicrob. Agents Chemother., Vol 48 (2004) pp. 2888-2896) was analyzed in the presence of different lantibiotics. We could show dose-dependent cell wall biosynthesis stress of reporter cells in response to the action of the lantibiotics subtilin produced by B. subtilis, epidermin and gallidermin of Staphylococcus epidermidis or S. gallinarum, respectively, in both, agar-plate and liquid culture-based assays. Surprisingly, also cinnamycin of Streptomyces cinnamoneus cinnamoneus), previously known to bind specifically to phosphatidylethanolamin of biological membranes, provoked strong cell wall biosynthetic stress. Our results show that our system can be used for screening purposes, for example to discover novel inhibitors of cell wall biosynthesis.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_008

Imaging peptidoglycan biosynthesis in Bacillus subtilis with fluorescent antibiotics. The peptidoglycan (PG) layers surrounding bacterial cells play an important role in determining cell shape. The machinery controlling when and where new PG is made is not understood, but is proposed to involve interactions between bacterial actin homologs such as Mbl, which forms helical cables within cells, and extracellular multiprotein complexes that include penicillin-binding proteins. It has been suggested that labeled antibiotics that bind to PG precursors may be useful for imaging PG to help determine the genes that control the biosynthesis of this polymer. Here, we compare the staining patterns observed in Bacillus subtilis using fluorescent derivatives of two PG-binding antibiotics, vancomycin and ramoplanin. The staining patterns for both probes exhibit a strong dependence on probe concentration, suggesting antibiotic-induced perturbations in PG synthesis. Ramoplanin probes may be better imaging agents than vancomycin probes because they yield clear staining patterns at concentrations well below their minimum inhibitory concentrations. Under some conditions, both ramoplanin and vancomycin probes produce helicoid staining patterns along the cylindrical walls of B. subtilis cells. This sidewall staining is observed in the absence of the cytoskeletal protein Mbl. Although Mbl plays an important role in cell shape determination, our data indicate that other proteins control the spatial localization of the biosynthetic complexes responsible for new PG synthesis along the walls of B. subtilis cells.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_009

Imaging peptidoglycan biosynthesis in Bacillus subtilis with fluorescent antibiotics. The peptidoglycan (PG) layers surrounding bacterial cells play an important role in determining cell shape. The machinery controlling when and where new PG is made is not understood, but is proposed to involve interactions between bacterial actin homologs such as Mbl, which forms helical cables within cells, and extracellular multiprotein complexes that include penicillin-binding proteins. It has been suggested that labeled antibiotics that bind to PG precursors may be useful for imaging PG to help determine the genes that control the biosynthesis of this polymer. Here, we compare the staining patterns observed in Bacillus subtilis using fluorescent derivatives of two PG-binding antibiotics, vancomycin and ramoplanin. The staining patterns for both probes exhibit a strong dependence on probe concentration, suggesting antibiotic-induced perturbations in PG synthesis. Ramoplanin probes may be better imaging agents than vancomycin probes because they yield clear staining patterns at concentrations well below their minimum inhibitory concentrations. Under some conditions, both ramoplanin and vancomycin probes produce helicoid staining patterns along the cylindrical walls of B. subtilis cells. This sidewall staining is observed in the absence of the cytoskeletal protein Mbl. Although Mbl plays an important role in cell shape determination, our data indicate that other proteins control the spatial localization of the biosynthetic complexes responsible for new PG synthesis along the walls of B. subtilis cells.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_010

Imaging peptidoglycan biosynthesis in Bacillus subtilis with fluorescent antibiotics. The peptidoglycan (PG) layers surrounding bacterial cells play an important role in determining cell shape. The machinery controlling when and where new PG is made is not understood, but is proposed to involve interactions between bacterial actin homologs such as Mbl, which forms helical cables within cells, and extracellular multiprotein complexes that include penicillin-binding proteins. It has been suggested that labeled antibiotics that bind to PG precursors may be useful for imaging PG to help determine the genes that control the biosynthesis of this polymer. Here, we compare the staining patterns observed in Bacillus subtilis using fluorescent derivatives of two PG-binding antibiotics, vancomycin and ramoplanin. The staining patterns for both probes exhibit a strong dependence on probe concentration, suggesting antibiotic-induced perturbations in PG synthesis. Ramoplanin probes may be better imaging agents than vancomycin probes because they yield clear staining patterns at concentrations well below their minimum inhibitory concentrations. Under some conditions, both ramoplanin and vancomycin probes produce helicoid staining patterns along the cylindrical walls of B. subtilis cells. This sidewall staining is observed in the absence of the cytoskeletal protein Mbl. Although Mbl plays an important role in cell shape determination, our data indicate that other proteins control the spatial localization of the biosynthetic complexes responsible for new PG synthesis along the walls of B. subtilis cells.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_011

Imaging peptidoglycan biosynthesis in Bacillus subtilis with fluorescent antibiotics. The peptidoglycan (PG) layers surrounding bacterial cells play an important role in determining cell shape. The machinery controlling when and where new PG is made is not understood, but is proposed to involve interactions between bacterial actin homologs such as Mbl, which forms helical cables within cells, and extracellular multiprotein complexes that include penicillin-binding proteins. It has been suggested that labeled antibiotics that bind to PG precursors may be useful for imaging PG to help determine the genes that control the biosynthesis of this polymer. Here, we compare the staining patterns observed in Bacillus subtilis using fluorescent derivatives of two PG-binding antibiotics, vancomycin and ramoplanin. The staining patterns for both probes exhibit a strong dependence on probe concentration, suggesting antibiotic-induced perturbations in PG synthesis. Ramoplanin probes may be better imaging agents than vancomycin probes because they yield clear staining patterns at concentrations well below their minimum inhibitory concentrations. Under some conditions, both ramoplanin and vancomycin probes produce helicoid staining patterns along the cylindrical walls of B. subtilis cells. This sidewall staining is observed in the absence of the cytoskeletal protein Mbl. Although Mbl plays an important role in cell shape determination, our data indicate that other proteins control the spatial localization of the biosynthetic complexes responsible for new PG synthesis along the walls of B. subtilis cells.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_012

Structures of the muraymycins, novel peptidoglycan biosynthesis inhibitors. The muraymycins, a family of nucleoside-lipopeptide antibiotics, were purified from the extract of Streptomyces sp. LL-AA896. The antibiotics were purified by chromatographic methods and characterized by NMR spectroscopy, degradation studies, and mass spectrometry. The structures of 19 compounds were established. The muraymycins constitute a new antibiotic family whose core structure contains a glycosylated uronic acid derivative joined by an aminopropane group to a hexahydro-2-imino-4-pyrimidylglycyl residue (epicapreomycidine) containing dipeptide that is further extended by a urea-valine moiety. Members of this family show broad-spectrum in vitro antimicrobial activity against a variety of clinical isolates (MIC 2 to >64 mug/mL). The muraymycins inhibited peptidoglycan biosynthesis. The fatty acid substituent and the presence or absence of the amino sugar play important roles in biological activity. One of the most active compounds, muraymycin A1, demonstrated protection in vivo against Staphylococcus aureus infection in mice (ED50 1.1 mg/kg).

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_013

Structures of the muraymycins, novel peptidoglycan biosynthesis inhibitors. The muraymycins, a family of nucleoside-lipopeptide antibiotics, were purified from the extract of Streptomyces sp. LL-AA896. The antibiotics were purified by chromatographic methods and characterized by NMR spectroscopy, degradation studies, and mass spectrometry. The structures of 19 compounds were established. The muraymycins constitute a new antibiotic family whose core structure contains a glycosylated uronic acid derivative joined by an aminopropane group to a hexahydro-2-imino-4-pyrimidylglycyl residue (epicapreomycidine) containing dipeptide that is further extended by a urea-valine moiety. Members of this family show broad-spectrum in vitro antimicrobial activity against a variety of clinical isolates (MIC 2 to >64 mug/mL). The muraymycins inhibited peptidoglycan biosynthesis. The fatty acid substituent and the presence or absence of the amino sugar play important roles in biological activity. One of the most active compounds, muraymycin A1, demonstrated protection in vivo against Staphylococcus aureus infection in mice (ED50 1.1 mg/kg).

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_014

Structures of the muraymycins, novel peptidoglycan biosynthesis inhibitors. The muraymycins, a family of nucleoside-lipopeptide antibiotics, were purified from the extract of Streptomyces sp. LL-AA896. The antibiotics were purified by chromatographic methods and characterized by NMR spectroscopy, degradation studies, and mass spectrometry. The structures of 19 compounds were established. The muraymycins constitute a new antibiotic family whose core structure contains a glycosylated uronic acid derivative joined by an aminopropane group to a hexahydro-2-imino-4-pyrimidylglycyl residue (epicapreomycidine) containing dipeptide that is further extended by a urea-valine moiety. Members of this family show broad-spectrum in vitro antimicrobial activity against a variety of clinical isolates (MIC 2 to >64 mug/mL). The muraymycins inhibited peptidoglycan biosynthesis. The fatty acid substituent and the presence or absence of the amino sugar play important roles in biological activity. One of the most active compounds, muraymycin A1, demonstrated protection in vivo against Staphylococcus aureus infection in mice (ED50 1.1 mg/kg).

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_015

Rethinking ramoplanin: the role of substrate binding in inhibition of peptidoglycan biosynthesis. Ramoplanin is a cyclicdepsipeptide antibiotic that inhibits peptidoglycan biosynthesis. It was proposed in 1990 to block the MurG step of peptidoglycan synthesis by binding to the substrate of MurG, Lipid I. The proposed mechanism of MurG inhibition has become widely accepted even though it was never directly tested. In this paper, we disprove the accepted mechanism for how ramoplanin functions, and we present an alternative mechanism. This work has implications for the design of ramoplanin derivatives and may influence how other proposed substrate binding antibiotics are studied.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_016

Rethinking ramoplanin: the role of substrate binding in inhibition of peptidoglycan biosynthesis. Ramoplanin is a cyclicdepsipeptide antibiotic that inhibits peptidoglycan biosynthesis. It was proposed in 1990 to block the MurG step of peptidoglycan synthesis by binding to the substrate of MurG, Lipid I. The proposed mechanism of MurG inhibition has become widely accepted even though it was never directly tested. In this paper, we disprove the accepted mechanism for how ramoplanin functions, and we present an alternative mechanism. This work has implications for the design of ramoplanin derivatives and may influence how other proposed substrate binding antibiotics are studied.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_017

Vancomycin resistance in enterococci: reprogramming of the D-ala-D-Ala ligases in bacterial peptidoglycan biosynthesis. Vancomycin binds to bacterial cell-wall intermediates to achieve its antibiotic effect. Infections of vancomycin-resistant enterococci are, however, becoming an increasing problem; the bacteria are resistant because they synthesize different cell-wall intermediates. The enzymes involved in cell-wall biosynthesis, therefore, are potential targets for combating this resistance. Recent biochemical and crystallographic results are providing mechanistic and structural details about some of these targets.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_018

The lantibiotic mersacidin inhibits peptidoglycan biosynthesis at the level of transglycosylation. The lantibiotic mersacidin has been previously reported to interfere with bacterial peptidoglycan biosynthesis, [Brötz, H., Bierbaum, G., Markus, A., Molitor, E. & Sahl, H.-G. (1995) Antimicrob. Agents Chemother. 39, 714-719]. Here, we focus on the target reaction and describe a mersacidin-induced accumulation of UDP-N-acetylmuramoyl-pentapeptide, indicating that inhibition of peptidoglycan synthesis occurs after the formation of cytoplasmic precursors. In vitro studies involving a wall-membrane particulate fraction of Bacillus megaterium KM demonstrated that mersacidin did not prevent the synthesis of lipid II [undecaprenyl-diphosphoryl-N-acetylmuramoyl-(pentapeptide)-N-ac ety lglucosamine] but specifically the subsequent conversion of this intermediate into polymeric nascent glycan strands by transglycosylation. Comparison with other inhibitors of transglycosylation shows that the effective concentration of mersacidin in vitro is in the range of that of the glycopeptide antibiotic vancomycin but 2-3 orders of magnitude higher than that of the competitive enzyme inhibitor moenomycin. The analogy to the glycopeptides may hint at an interaction of mersacidin with the peptidoglycan precursor rather than with the enzyme. Unlike vancomycin however, mersacidin inhibits peptidoglycan formation from UDP-N-acetylmuramoyl-tripeptide and is active against Enterococcus faecium expressing the vanA resistance gene cluster. This indicates that the molecular target site of mersacidin differs from that of vancomycin and that no cross-resistance exists between the two antibiotics.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_019

The lantibiotic mersacidin inhibits peptidoglycan biosynthesis at the level of transglycosylation. The lantibiotic mersacidin has been previously reported to interfere with bacterial peptidoglycan biosynthesis, [Brötz, H., Bierbaum, G., Markus, A., Molitor, E. & Sahl, H.-G. (1995) Antimicrob. Agents Chemother. 39, 714-719]. Here, we focus on the target reaction and describe a mersacidin-induced accumulation of UDP-N-acetylmuramoyl-pentapeptide, indicating that inhibition of peptidoglycan synthesis occurs after the formation of cytoplasmic precursors. In vitro studies involving a wall-membrane particulate fraction of Bacillus megaterium KM demonstrated that mersacidin did not prevent the synthesis of lipid II [undecaprenyl-diphosphoryl-N-acetylmuramoyl-(pentapeptide)-N-ac ety lglucosamine] but specifically the subsequent conversion of this intermediate into polymeric nascent glycan strands by transglycosylation. Comparison with other inhibitors of transglycosylation shows that the effective concentration of mersacidin in vitro is in the range of that of the glycopeptide antibiotic vancomycin but 2-3 orders of magnitude higher than that of the competitive enzyme inhibitor moenomycin. The analogy to the glycopeptides may hint at an interaction of mersacidin with the peptidoglycan precursor rather than with the enzyme. Unlike vancomycin however, mersacidin inhibits peptidoglycan formation from UDP-N-acetylmuramoyl-tripeptide and is active against Enterococcus faecium expressing the vanA resistance gene cluster. This indicates that the molecular target site of mersacidin differs from that of vancomycin and that no cross-resistance exists between the two antibiotics.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_020

The lantibiotic mersacidin inhibits peptidoglycan biosynthesis at the level of transglycosylation. The lantibiotic mersacidin has been previously reported to interfere with bacterial peptidoglycan biosynthesis, [Brötz, H., Bierbaum, G., Markus, A., Molitor, E. & Sahl, H.-G. (1995) Antimicrob. Agents Chemother. 39, 714-719]. Here, we focus on the target reaction and describe a mersacidin-induced accumulation of UDP-N-acetylmuramoyl-pentapeptide, indicating that inhibition of peptidoglycan synthesis occurs after the formation of cytoplasmic precursors. In vitro studies involving a wall-membrane particulate fraction of Bacillus megaterium KM demonstrated that mersacidin did not prevent the synthesis of lipid II [undecaprenyl-diphosphoryl-N-acetylmuramoyl-(pentapeptide)-N-ac ety lglucosamine] but specifically the subsequent conversion of this intermediate into polymeric nascent glycan strands by transglycosylation. Comparison with other inhibitors of transglycosylation shows that the effective concentration of mersacidin in vitro is in the range of that of the glycopeptide antibiotic vancomycin but 2-3 orders of magnitude higher than that of the competitive enzyme inhibitor moenomycin. The analogy to the glycopeptides may hint at an interaction of mersacidin with the peptidoglycan precursor rather than with the enzyme. Unlike vancomycin however, mersacidin inhibits peptidoglycan formation from UDP-N-acetylmuramoyl-tripeptide and is active against Enterococcus faecium expressing the vanA resistance gene cluster. This indicates that the molecular target site of mersacidin differs from that of vancomycin and that no cross-resistance exists between the two antibiotics.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_021

The lantibiotic mersacidin inhibits peptidoglycan biosynthesis at the level of transglycosylation. The lantibiotic mersacidin has been previously reported to interfere with bacterial peptidoglycan biosynthesis, [Brötz, H., Bierbaum, G., Markus, A., Molitor, E. & Sahl, H.-G. (1995) Antimicrob. Agents Chemother. 39, 714-719]. Here, we focus on the target reaction and describe a mersacidin-induced accumulation of UDP-N-acetylmuramoyl-pentapeptide, indicating that inhibition of peptidoglycan synthesis occurs after the formation of cytoplasmic precursors. In vitro studies involving a wall-membrane particulate fraction of Bacillus megaterium KM demonstrated that mersacidin did not prevent the synthesis of lipid II [undecaprenyl-diphosphoryl-N-acetylmuramoyl-(pentapeptide)-N-ac ety lglucosamine] but specifically the subsequent conversion of this intermediate into polymeric nascent glycan strands by transglycosylation. Comparison with other inhibitors of transglycosylation shows that the effective concentration of mersacidin in vitro is in the range of that of the glycopeptide antibiotic vancomycin but 2-3 orders of magnitude higher than that of the competitive enzyme inhibitor moenomycin. The analogy to the glycopeptides may hint at an interaction of mersacidin with the peptidoglycan precursor rather than with the enzyme. Unlike vancomycin however, mersacidin inhibits peptidoglycan formation from UDP-N-acetylmuramoyl-tripeptide and is active against Enterococcus faecium expressing the vanA resistance gene cluster. This indicates that the molecular target site of mersacidin differs from that of vancomycin and that no cross-resistance exists between the two antibiotics.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_022

The lantibiotic mersacidin inhibits peptidoglycan biosynthesis at the level of transglycosylation. The lantibiotic mersacidin has been previously reported to interfere with bacterial peptidoglycan biosynthesis, [Brötz, H., Bierbaum, G., Markus, A., Molitor, E. & Sahl, H.-G. (1995) Antimicrob. Agents Chemother. 39, 714-719]. Here, we focus on the target reaction and describe a mersacidin-induced accumulation of UDP-N-acetylmuramoyl-pentapeptide, indicating that inhibition of peptidoglycan synthesis occurs after the formation of cytoplasmic precursors. In vitro studies involving a wall-membrane particulate fraction of Bacillus megaterium KM demonstrated that mersacidin did not prevent the synthesis of lipid II [undecaprenyl-diphosphoryl-N-acetylmuramoyl-(pentapeptide)-N-ac ety lglucosamine] but specifically the subsequent conversion of this intermediate into polymeric nascent glycan strands by transglycosylation. Comparison with other inhibitors of transglycosylation shows that the effective concentration of mersacidin in vitro is in the range of that of the glycopeptide antibiotic vancomycin but 2-3 orders of magnitude higher than that of the competitive enzyme inhibitor moenomycin. The analogy to the glycopeptides may hint at an interaction of mersacidin with the peptidoglycan precursor rather than with the enzyme. Unlike vancomycin however, mersacidin inhibits peptidoglycan formation from UDP-N-acetylmuramoyl-tripeptide and is active against Enterococcus faecium expressing the vanA resistance gene cluster. This indicates that the molecular target site of mersacidin differs from that of vancomycin and that no cross-resistance exists between the two antibiotics.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_023

The lantibiotic mersacidin inhibits peptidoglycan biosynthesis at the level of transglycosylation. The lantibiotic mersacidin has been previously reported to interfere with bacterial peptidoglycan biosynthesis, [Brötz, H., Bierbaum, G., Markus, A., Molitor, E. & Sahl, H.-G. (1995) Antimicrob. Agents Chemother. 39, 714-719]. Here, we focus on the target reaction and describe a mersacidin-induced accumulation of UDP-N-acetylmuramoyl-pentapeptide, indicating that inhibition of peptidoglycan synthesis occurs after the formation of cytoplasmic precursors. In vitro studies involving a wall-membrane particulate fraction of Bacillus megaterium KM demonstrated that mersacidin did not prevent the synthesis of lipid II [undecaprenyl-diphosphoryl-N-acetylmuramoyl-(pentapeptide)-N-ac ety lglucosamine] but specifically the subsequent conversion of this intermediate into polymeric nascent glycan strands by transglycosylation. Comparison with other inhibitors of transglycosylation shows that the effective concentration of mersacidin in vitro is in the range of that of the glycopeptide antibiotic vancomycin but 2-3 orders of magnitude higher than that of the competitive enzyme inhibitor moenomycin. The analogy to the glycopeptides may hint at an interaction of mersacidin with the peptidoglycan precursor rather than with the enzyme. Unlike vancomycin however, mersacidin inhibits peptidoglycan formation from UDP-N-acetylmuramoyl-tripeptide and is active against Enterococcus faecium expressing the vanA resistance gene cluster. This indicates that the molecular target site of mersacidin differs from that of vancomycin and that no cross-resistance exists between the two antibiotics.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_024

Inhibition of peptidoglycan biosynthesis in vancomycin-susceptible and -resistant bacteria by a semisynthetic glycopeptide antibiotic. LY191145 is a p-chlorobenzyl derivative of LY264826 (A82846B) with activity against both vancomycin-susceptible and -resistant enterococci. Incorporation of L-[14C]lysine into peptidoglycan of intact vancomycin-susceptible and -resistant Enterococcus faecium was inhibited by LY191145 (50% inhibitory concentrations of 1 and 5 microgram/ml, respectively). Inhibition was accompanied by accumulation of UDP-muramyl-peptide precursors in the cytoplasm. This agent inhibited late-stage steps in peptidoglycan biosynthesis in permeabilized E. faecium when either the UDP-muramyl-pentapeptide precursor from vancomycin-susceptible E. faecium or the UDP-muramyl-pentadepsipeptide precursor from vancomycin-resistant E. faecium was used as a substrate. Inhibition of late-stage steps led to accumulation of an N-acetyl-[14C]glucosamine-labeled lipid intermediate indicative of inhibition of the transglycosylation step. Inhibition of peptidoglycan polymerization without affecting cross-linking in a particulate membrane-plus-wall-fragment assay from Aerococcus viridans was consistent with this explanation. The fact that inhibition of peptidoglycan biosynthesis by LY191145 was not readily antagonized by an excess of free acyl-D-alanyl-D-alanine or acyl-D-alanyl-D-lactate ligands indicates that the manner in which this compound inhibits transglycosylation may not be identical to that of vancomycin.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_025

Inhibition of peptidoglycan biosynthesis in vancomycin-susceptible and -resistant bacteria by a semisynthetic glycopeptide antibiotic. LY191145 is a p-chlorobenzyl derivative of LY264826 (A82846B) with activity against both vancomycin-susceptible and -resistant enterococci. Incorporation of L-[14C]lysine into peptidoglycan of intact vancomycin-susceptible and -resistant Enterococcus faecium was inhibited by LY191145 (50% inhibitory concentrations of 1 and 5 microgram/ml, respectively). Inhibition was accompanied by accumulation of UDP-muramyl-peptide precursors in the cytoplasm. This agent inhibited late-stage steps in peptidoglycan biosynthesis in permeabilized E. faecium when either the UDP-muramyl-pentapeptide precursor from vancomycin-susceptible E. faecium or the UDP-muramyl-pentadepsipeptide precursor from vancomycin-resistant E. faecium was used as a substrate. Inhibition of late-stage steps led to accumulation of an N-acetyl-[14C]glucosamine-labeled lipid intermediate indicative of inhibition of the transglycosylation step. Inhibition of peptidoglycan polymerization without affecting cross-linking in a particulate membrane-plus-wall-fragment assay from Aerococcus viridans was consistent with this explanation. The fact that inhibition of peptidoglycan biosynthesis by LY191145 was not readily antagonized by an excess of free acyl-D-alanyl-D-alanine or acyl-D-alanyl-D-lactate ligands indicates that the manner in which this compound inhibits transglycosylation may not be identical to that of vancomycin.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_026

Inhibition of peptidoglycan biosynthesis in vancomycin-susceptible and -resistant bacteria by a semisynthetic glycopeptide antibiotic. LY191145 is a p-chlorobenzyl derivative of LY264826 (A82846B) with activity against both vancomycin-susceptible and -resistant enterococci. Incorporation of L-[14C]lysine into peptidoglycan of intact vancomycin-susceptible and -resistant Enterococcus faecium was inhibited by LY191145 (50% inhibitory concentrations of 1 and 5 microgram/ml, respectively). Inhibition was accompanied by accumulation of UDP-muramyl-peptide precursors in the cytoplasm. This agent inhibited late-stage steps in peptidoglycan biosynthesis in permeabilized E. faecium when either the UDP-muramyl-pentapeptide precursor from vancomycin-susceptible E. faecium or the UDP-muramyl-pentadepsipeptide precursor from vancomycin-resistant E. faecium was used as a substrate. Inhibition of late-stage steps led to accumulation of an N-acetyl-[14C]glucosamine-labeled lipid intermediate indicative of inhibition of the transglycosylation step. Inhibition of peptidoglycan polymerization without affecting cross-linking in a particulate membrane-plus-wall-fragment assay from Aerococcus viridans was consistent with this explanation. The fact that inhibition of peptidoglycan biosynthesis by LY191145 was not readily antagonized by an excess of free acyl-D-alanyl-D-alanine or acyl-D-alanyl-D-lactate ligands indicates that the manner in which this compound inhibits transglycosylation may not be identical to that of vancomycin.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_027

Inhibition of peptidoglycan biosynthesis in vancomycin-susceptible and -resistant bacteria by a semisynthetic glycopeptide antibiotic. LY191145 is a p-chlorobenzyl derivative of LY264826 (A82846B) with activity against both vancomycin-susceptible and -resistant enterococci. Incorporation of L-[14C]lysine into peptidoglycan of intact vancomycin-susceptible and -resistant Enterococcus faecium was inhibited by LY191145 (50% inhibitory concentrations of 1 and 5 microgram/ml, respectively). Inhibition was accompanied by accumulation of UDP-muramyl-peptide precursors in the cytoplasm. This agent inhibited late-stage steps in peptidoglycan biosynthesis in permeabilized E. faecium when either the UDP-muramyl-pentapeptide precursor from vancomycin-susceptible E. faecium or the UDP-muramyl-pentadepsipeptide precursor from vancomycin-resistant E. faecium was used as a substrate. Inhibition of late-stage steps led to accumulation of an N-acetyl-[14C]glucosamine-labeled lipid intermediate indicative of inhibition of the transglycosylation step. Inhibition of peptidoglycan polymerization without affecting cross-linking in a particulate membrane-plus-wall-fragment assay from Aerococcus viridans was consistent with this explanation. The fact that inhibition of peptidoglycan biosynthesis by LY191145 was not readily antagonized by an excess of free acyl-D-alanyl-D-alanine or acyl-D-alanyl-D-lactate ligands indicates that the manner in which this compound inhibits transglycosylation may not be identical to that of vancomycin.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_028

Mode of action of the lantibiotic mersacidin: inhibition of peptidoglycan biosynthesis via a novel mechanism? Mersacidin is an antibiotic peptide produced by Bacillus sp. strain HIL Y-85,54728 that belongs to the group of lantibiotics. Its activity in vivo against methicillin-resistant Staphylococcus aureus strains compares with that of the glycopeptide antibiotic vancomycin (S. Chatterjee, D. K. Chatterjee, R. H. Jani, J. Blumbach, B. N. Ganguli, N. Klesel, M. Limbert, and G. Seibert, J. Antibiot. 45:839-845, 1992). Incubation of Staphylococcus simulans 22 with mersacidin resulted in the cessation of growth and slow lysis. Biosyntheses of DNA, RNA, and protein were not affected, whereas incorporation of glucose and D-alanine was inhibited and a regular reduction in the level of cell wall thickness was observed. Thus, unlike type A lantibiotics, mersacidin does not form pores in the cytoplasmic membrane but rather inhibits cell wall biosynthesis. Comparison with tunicamycin-treated cells indicated that peptidoglycan rather than teichoic acid metabolism is primarily affected. Mersacidin caused the excretion of a putative cell wall precursor into the culture supernatant. The formation of polymeric peptidoglycan was effectively inhibited in an in vitro assay, probably on the level of transglycosylation. In contrast to vancomycin, the activity of mersacidin was not antagonized by the tripeptide diacetyl-L-Lys-D-Ala-D-Ala, indicating that on the molecular level its mode of action differs from those of glycopeptide antibiotics. These data together with electron microscopy suggest that mersacidin acts on a novel target, which opens new perspectives for the treatment of methicillin-resistant S. aureus.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_029

Mode of action of the lantibiotic mersacidin: inhibition of peptidoglycan biosynthesis via a novel mechanism? Mersacidin is an antibiotic peptide produced by Bacillus sp. strain HIL Y-85,54728 that belongs to the group of lantibiotics. Its activity in vivo against methicillin-resistant Staphylococcus aureus strains compares with that of the glycopeptide antibiotic vancomycin (S. Chatterjee, D. K. Chatterjee, R. H. Jani, J. Blumbach, B. N. Ganguli, N. Klesel, M. Limbert, and G. Seibert, J. Antibiot. 45:839-845, 1992). Incubation of Staphylococcus simulans 22 with mersacidin resulted in the cessation of growth and slow lysis. Biosyntheses of DNA, RNA, and protein were not affected, whereas incorporation of glucose and D-alanine was inhibited and a regular reduction in the level of cell wall thickness was observed. Thus, unlike type A lantibiotics, mersacidin does not form pores in the cytoplasmic membrane but rather inhibits cell wall biosynthesis. Comparison with tunicamycin-treated cells indicated that peptidoglycan rather than teichoic acid metabolism is primarily affected. Mersacidin caused the excretion of a putative cell wall precursor into the culture supernatant. The formation of polymeric peptidoglycan was effectively inhibited in an in vitro assay, probably on the level of transglycosylation. In contrast to vancomycin, the activity of mersacidin was not antagonized by the tripeptide diacetyl-L-Lys-D-Ala-D-Ala, indicating that on the molecular level its mode of action differs from those of glycopeptide antibiotics. These data together with electron microscopy suggest that mersacidin acts on a novel target, which opens new perspectives for the treatment of methicillin-resistant S. aureus.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_030

Mode of action of the lantibiotic mersacidin: inhibition of peptidoglycan biosynthesis via a novel mechanism? Mersacidin is an antibiotic peptide produced by Bacillus sp. strain HIL Y-85,54728 that belongs to the group of lantibiotics. Its activity in vivo against methicillin-resistant Staphylococcus aureus strains compares with that of the glycopeptide antibiotic vancomycin (S. Chatterjee, D. K. Chatterjee, R. H. Jani, J. Blumbach, B. N. Ganguli, N. Klesel, M. Limbert, and G. Seibert, J. Antibiot. 45:839-845, 1992). Incubation of Staphylococcus simulans 22 with mersacidin resulted in the cessation of growth and slow lysis. Biosyntheses of DNA, RNA, and protein were not affected, whereas incorporation of glucose and D-alanine was inhibited and a regular reduction in the level of cell wall thickness was observed. Thus, unlike type A lantibiotics, mersacidin does not form pores in the cytoplasmic membrane but rather inhibits cell wall biosynthesis. Comparison with tunicamycin-treated cells indicated that peptidoglycan rather than teichoic acid metabolism is primarily affected. Mersacidin caused the excretion of a putative cell wall precursor into the culture supernatant. The formation of polymeric peptidoglycan was effectively inhibited in an in vitro assay, probably on the level of transglycosylation. In contrast to vancomycin, the activity of mersacidin was not antagonized by the tripeptide diacetyl-L-Lys-D-Ala-D-Ala, indicating that on the molecular level its mode of action differs from those of glycopeptide antibiotics. These data together with electron microscopy suggest that mersacidin acts on a novel target, which opens new perspectives for the treatment of methicillin-resistant S. aureus.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_031

Mode of action of the lantibiotic mersacidin: inhibition of peptidoglycan biosynthesis via a novel mechanism? Mersacidin is an antibiotic peptide produced by Bacillus sp. strain HIL Y-85,54728 that belongs to the group of lantibiotics. Its activity in vivo against methicillin-resistant Staphylococcus aureus strains compares with that of the glycopeptide antibiotic vancomycin (S. Chatterjee, D. K. Chatterjee, R. H. Jani, J. Blumbach, B. N. Ganguli, N. Klesel, M. Limbert, and G. Seibert, J. Antibiot. 45:839-845, 1992). Incubation of Staphylococcus simulans 22 with mersacidin resulted in the cessation of growth and slow lysis. Biosyntheses of DNA, RNA, and protein were not affected, whereas incorporation of glucose and D-alanine was inhibited and a regular reduction in the level of cell wall thickness was observed. Thus, unlike type A lantibiotics, mersacidin does not form pores in the cytoplasmic membrane but rather inhibits cell wall biosynthesis. Comparison with tunicamycin-treated cells indicated that peptidoglycan rather than teichoic acid metabolism is primarily affected. Mersacidin caused the excretion of a putative cell wall precursor into the culture supernatant. The formation of polymeric peptidoglycan was effectively inhibited in an in vitro assay, probably on the level of transglycosylation. In contrast to vancomycin, the activity of mersacidin was not antagonized by the tripeptide diacetyl-L-Lys-D-Ala-D-Ala, indicating that on the molecular level its mode of action differs from those of glycopeptide antibiotics. These data together with electron microscopy suggest that mersacidin acts on a novel target, which opens new perspectives for the treatment of methicillin-resistant S. aureus.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_032

Mode of action of the lantibiotic mersacidin: inhibition of peptidoglycan biosynthesis via a novel mechanism? Mersacidin is an antibiotic peptide produced by Bacillus sp. strain HIL Y-85,54728 that belongs to the group of lantibiotics. Its activity in vivo against methicillin-resistant Staphylococcus aureus strains compares with that of the glycopeptide antibiotic vancomycin (S. Chatterjee, D. K. Chatterjee, R. H. Jani, J. Blumbach, B. N. Ganguli, N. Klesel, M. Limbert, and G. Seibert, J. Antibiot. 45:839-845, 1992). Incubation of Staphylococcus simulans 22 with mersacidin resulted in the cessation of growth and slow lysis. Biosyntheses of DNA, RNA, and protein were not affected, whereas incorporation of glucose and D-alanine was inhibited and a regular reduction in the level of cell wall thickness was observed. Thus, unlike type A lantibiotics, mersacidin does not form pores in the cytoplasmic membrane but rather inhibits cell wall biosynthesis. Comparison with tunicamycin-treated cells indicated that peptidoglycan rather than teichoic acid metabolism is primarily affected. Mersacidin caused the excretion of a putative cell wall precursor into the culture supernatant. The formation of polymeric peptidoglycan was effectively inhibited in an in vitro assay, probably on the level of transglycosylation. In contrast to vancomycin, the activity of mersacidin was not antagonized by the tripeptide diacetyl-L-Lys-D-Ala-D-Ala, indicating that on the molecular level its mode of action differs from those of glycopeptide antibiotics. These data together with electron microscopy suggest that mersacidin acts on a novel target, which opens new perspectives for the treatment of methicillin-resistant S. aureus.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_033

Mode of action of the lantibiotic mersacidin: inhibition of peptidoglycan biosynthesis via a novel mechanism? Mersacidin is an antibiotic peptide produced by Bacillus sp. strain HIL Y-85,54728 that belongs to the group of lantibiotics. Its activity in vivo against methicillin-resistant Staphylococcus aureus strains compares with that of the glycopeptide antibiotic vancomycin (S. Chatterjee, D. K. Chatterjee, R. H. Jani, J. Blumbach, B. N. Ganguli, N. Klesel, M. Limbert, and G. Seibert, J. Antibiot. 45:839-845, 1992). Incubation of Staphylococcus simulans 22 with mersacidin resulted in the cessation of growth and slow lysis. Biosyntheses of DNA, RNA, and protein were not affected, whereas incorporation of glucose and D-alanine was inhibited and a regular reduction in the level of cell wall thickness was observed. Thus, unlike type A lantibiotics, mersacidin does not form pores in the cytoplasmic membrane but rather inhibits cell wall biosynthesis. Comparison with tunicamycin-treated cells indicated that peptidoglycan rather than teichoic acid metabolism is primarily affected. Mersacidin caused the excretion of a putative cell wall precursor into the culture supernatant. The formation of polymeric peptidoglycan was effectively inhibited in an in vitro assay, probably on the level of transglycosylation. In contrast to vancomycin, the activity of mersacidin was not antagonized by the tripeptide diacetyl-L-Lys-D-Ala-D-Ala, indicating that on the molecular level its mode of action differs from those of glycopeptide antibiotics. These data together with electron microscopy suggest that mersacidin acts on a novel target, which opens new perspectives for the treatment of methicillin-resistant S. aureus.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_034

Mode of action of the lantibiotic mersacidin: inhibition of peptidoglycan biosynthesis via a novel mechanism? Mersacidin is an antibiotic peptide produced by Bacillus sp. strain HIL Y-85,54728 that belongs to the group of lantibiotics. Its activity in vivo against methicillin-resistant Staphylococcus aureus strains compares with that of the glycopeptide antibiotic vancomycin (S. Chatterjee, D. K. Chatterjee, R. H. Jani, J. Blumbach, B. N. Ganguli, N. Klesel, M. Limbert, and G. Seibert, J. Antibiot. 45:839-845, 1992). Incubation of Staphylococcus simulans 22 with mersacidin resulted in the cessation of growth and slow lysis. Biosyntheses of DNA, RNA, and protein were not affected, whereas incorporation of glucose and D-alanine was inhibited and a regular reduction in the level of cell wall thickness was observed. Thus, unlike type A lantibiotics, mersacidin does not form pores in the cytoplasmic membrane but rather inhibits cell wall biosynthesis. Comparison with tunicamycin-treated cells indicated that peptidoglycan rather than teichoic acid metabolism is primarily affected. Mersacidin caused the excretion of a putative cell wall precursor into the culture supernatant. The formation of polymeric peptidoglycan was effectively inhibited in an in vitro assay, probably on the level of transglycosylation. In contrast to vancomycin, the activity of mersacidin was not antagonized by the tripeptide diacetyl-L-Lys-D-Ala-D-Ala, indicating that on the molecular level its mode of action differs from those of glycopeptide antibiotics. These data together with electron microscopy suggest that mersacidin acts on a novel target, which opens new perspectives for the treatment of methicillin-resistant S. aureus.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_035

Inhibition of peptidoglycan biosynthesis by ramoplanin. Ramoplanin, a new lipoglycopeptide antibiotic, inhibits cell wall peptidoglycan biosynthesis in gram-positive bacteria. In both Staphylococcus aureus and Bacillus megaterium, UDP-N-acetylmuramyl-pentapeptides (UDP-MurNAc-pentapeptides) accumulated at concentrations of ramoplanin close to the MIC, indicating that inhibition of peptidoglycan biosynthesis occurred after formation of cytoplasmic precursors. Susceptible bacteria bound or accumulated approximately 5 x 10(4) molecules of ramoplanin per cell, only 1/100th of the amount of vancomycin which binds to groups within peptidoglycan conforming to the pattern L-alpha alpha (amino acid)-D-alpha alpha-D-alpha alpha, suggesting that ramoplanin has a different target site. This was confirmed by in vitro studies involving a wall-membrane particulate fraction from Gaffkya homari in which peptidoglycan synthesis from UDP-MurNAc-tetrapeptide was inhibited by ramoplanin but not by vancomycin. The incorporation of peptidoglycan precursors into nascent peptidoglycan of a toluenized cell preparation of B. megaterium was inhibited by ramoplanin, indicating that the antibiotic acts at a step before transpeptidation. In vitro studies of a wall-membrane particulate fraction of B. megaterium indicated that ramoplanin did not prevent the formation of lipid intermediate I (undecaprenyl-P-P-MurNAc-pentapeptide) but inhibited the next reaction in which N-acetylglucosamine is transferred to that lipid intermediate. The high concentrations required to inhibit in vitro peptidoglycan-synthesizing systems probably reflect the high concentrations of target sites present. High concentrations of ramoplanin also damage certain properties of the cell membrane, but low concentrations only affected wall synthesis in intact bacteria without perturbing membrane function. These studies indicate that the primary target of ramoplanin is peptidoglycan biosynthesis and that the probable reaction inhibited is the N-acetylglucosaminyltransferase-catalyzed conversion of lipid intermediate I to lipid intermediate II.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_036

Inhibition of peptidoglycan biosynthesis by ramoplanin. Ramoplanin, a new lipoglycopeptide antibiotic, inhibits cell wall peptidoglycan biosynthesis in gram-positive bacteria. In both Staphylococcus aureus and Bacillus megaterium, UDP-N-acetylmuramyl-pentapeptides (UDP-MurNAc-pentapeptides) accumulated at concentrations of ramoplanin close to the MIC, indicating that inhibition of peptidoglycan biosynthesis occurred after formation of cytoplasmic precursors. Susceptible bacteria bound or accumulated approximately 5 x 10(4) molecules of ramoplanin per cell, only 1/100th of the amount of vancomycin which binds to groups within peptidoglycan conforming to the pattern L-alpha alpha (amino acid)-D-alpha alpha-D-alpha alpha, suggesting that ramoplanin has a different target site. This was confirmed by in vitro studies involving a wall-membrane particulate fraction from Gaffkya homari in which peptidoglycan synthesis from UDP-MurNAc-tetrapeptide was inhibited by ramoplanin but not by vancomycin. The incorporation of peptidoglycan precursors into nascent peptidoglycan of a toluenized cell preparation of B. megaterium was inhibited by ramoplanin, indicating that the antibiotic acts at a step before transpeptidation. In vitro studies of a wall-membrane particulate fraction of B. megaterium indicated that ramoplanin did not prevent the formation of lipid intermediate I (undecaprenyl-P-P-MurNAc-pentapeptide) but inhibited the next reaction in which N-acetylglucosamine is transferred to that lipid intermediate. The high concentrations required to inhibit in vitro peptidoglycan-synthesizing systems probably reflect the high concentrations of target sites present. High concentrations of ramoplanin also damage certain properties of the cell membrane, but low concentrations only affected wall synthesis in intact bacteria without perturbing membrane function. These studies indicate that the primary target of ramoplanin is peptidoglycan biosynthesis and that the probable reaction inhibited is the N-acetylglucosaminyltransferase-catalyzed conversion of lipid intermediate I to lipid intermediate II.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_037

Induction of vancomycin resistance in Enterococcus faecium by non-glycopeptide antibiotics. Bacitracin and other antibiotics that inhibit late stages in peptidoglycan biosynthesis induce vancomycin resistance in a high-level, inducibly vancomycin-resistant strain of Enterococcus faecium. Exposure to bacitracin led to synthesis of the lactate-containing UDP-MurNAc-pentadepsipeptide precursor required for vancomycin resistance. These findings indicate that inhibition of peptidoglycan biosynthesis can lead to induction of vancomycin resistance and raise the possibility that multiple signals may serve to induce resistance.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_038

Induction of vancomycin resistance in Enterococcus faecium by non-glycopeptide antibiotics. Bacitracin and other antibiotics that inhibit late stages in peptidoglycan biosynthesis induce vancomycin resistance in a high-level, inducibly vancomycin-resistant strain of Enterococcus faecium. Exposure to bacitracin led to synthesis of the lactate-containing UDP-MurNAc-pentadepsipeptide precursor required for vancomycin resistance. These findings indicate that inhibition of peptidoglycan biosynthesis can lead to induction of vancomycin resistance and raise the possibility that multiple signals may serve to induce resistance.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_039

Induction of vancomycin resistance in Enterococcus faecium by non-glycopeptide antibiotics. Bacitracin and other antibiotics that inhibit late stages in peptidoglycan biosynthesis induce vancomycin resistance in a high-level, inducibly vancomycin-resistant strain of Enterococcus faecium. Exposure to bacitracin led to synthesis of the lactate-containing UDP-MurNAc-pentadepsipeptide precursor required for vancomycin resistance. These findings indicate that inhibition of peptidoglycan biosynthesis can lead to induction of vancomycin resistance and raise the possibility that multiple signals may serve to induce resistance.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_040

Mycobacterium smegmatis D-Alanine Racemase Mutants Are Not Dependent on D-Alanine for Growth. Mycobacterium smegmatis is a fast-growing nonpathogenic species particularly useful in studying basic cellular processes of relevance to pathogenic mycobacteria. This study focused on the D-alanine racemase gene (alrA), which is involved in the synthesis of D-alanine, a basic component of peptidoglycan that forms the backbone of the cell wall. M. smegmatis alrA null mutants were generated by homologous recombination using a kanamycin resistance marker for insertional inactivation. Mutants were selected on Middlebrook medium supplemented with 50 mM D-alanine and 20 microg of kanamycin per ml. These mutants were also able to grow in standard and minimal media without D-alanine, giving rise to colonies with a drier appearance and more-raised borders than the wild-type strain. The viability of the mutants and independence of D-alanine for growth indicate that inactivation of alrA does not impose an auxotrophic requirement for D-alanine, suggesting the existence of a new pathway of D-alanine biosynthesis in M. smegmatis. Biochemical analysis demonstrated the absence of any detectable D-alanine racemase activity in the mutant strains. In addition, the alrA mutants displayed hypersusceptibility to the antimycobacterial agent D-cycloserine. The MIC of D-cycloserine for the mutant strain was 2.56 microg/ml, 30-fold less than that for the wild-type strain. Furthermore, this hypersusceptibility was confirmed by the bactericidal action of D-cycloserine on broth cultures. The kinetic of killing for the mutant strain followed the same pattern as that for the wild-type strain, but at a 30-fold-lower drug concentration. This effect does not involve a change in the permeability of the cell wall by this drug and is consistent with the identification of D-alanine racemase as a target of D-cycloserine. This outcome is of importance for the design of novel antituberculosis drugs targeting peptidoglycan biosynthesis in mycobacteria.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_041

Revealing fosfomycin primary effect on Staphylococcus aureus transcriptome: modulation of cell envelope biosynthesis and phosphoenolpyruvate induced starvation. BACKGROUND: Staphylococcus aureus is a highly adaptable human pathogen and there is a constant search for effective antibiotics. Fosfomycin is a potent irreversible inhibitor of MurA, an enolpyruvyl transferase that uses phosphoenolpyruvate as substrate. The goal of this study was to identify the pathways and processes primarily affected by fosfomycin at the genome-wide transcriptome level to aid development of new drugs. RESULTS: S. aureus ATCC 29213 cells were treated with sub-MIC concentrations of fosfomycin and harvested at 10, 20 and 40 minutes after treatment. S. aureus GeneChip statistical data analysis was complemented by gene set enrichment analysis. A visualization tool for mapping gene expression data into biological pathways was developed in order to identify the metabolic processes affected by fosfomycin. We have shown that the number of significantly differentially expressed genes in treated cultures increased with time and with increasing fosfomycin concentration. The target pathway - peptidoglycan biosynthesis - was upregulated following fosfomycin treatment. Modulation of transport processes, cofactor biosynthesis, energy metabolism and nucleic acid biosynthesis was also observed. CONCLUSIONS: Several pathways and genes downregulated by fosfomycin have been identified, in contrast to previously described cell wall active antibiotics, and was explained by starvation response induced by phosphoenolpyruvate accumulation. Transcriptomic profiling, in combination with meta-analysis, has been shown to be a valuable tool in determining bacterial response to a specific antibiotic.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_042

Revealing fosfomycin primary effect on Staphylococcus aureus transcriptome: modulation of cell envelope biosynthesis and phosphoenolpyruvate induced starvation. BACKGROUND: Staphylococcus aureus is a highly adaptable human pathogen and there is a constant search for effective antibiotics. Fosfomycin is a potent irreversible inhibitor of MurA, an enolpyruvyl transferase that uses phosphoenolpyruvate as substrate. The goal of this study was to identify the pathways and processes primarily affected by fosfomycin at the genome-wide transcriptome level to aid development of new drugs. RESULTS: S. aureus ATCC 29213 cells were treated with sub-MIC concentrations of fosfomycin and harvested at 10, 20 and 40 minutes after treatment. S. aureus GeneChip statistical data analysis was complemented by gene set enrichment analysis. A visualization tool for mapping gene expression data into biological pathways was developed in order to identify the metabolic processes affected by fosfomycin. We have shown that the number of significantly differentially expressed genes in treated cultures increased with time and with increasing fosfomycin concentration. The target pathway - peptidoglycan biosynthesis - was upregulated following fosfomycin treatment. Modulation of transport processes, cofactor biosynthesis, energy metabolism and nucleic acid biosynthesis was also observed. CONCLUSIONS: Several pathways and genes downregulated by fosfomycin have been identified, in contrast to previously described cell wall active antibiotics, and was explained by starvation response induced by phosphoenolpyruvate accumulation. Transcriptomic profiling, in combination with meta-analysis, has been shown to be a valuable tool in determining bacterial response to a specific antibiotic.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_043

Inhibition of peptidoglycan biosynthesis by ramoplanin. Ramoplanin, a new lipoglycopeptide antibiotic, inhibits cell wall peptidoglycan biosynthesis in gram-positive bacteria. In both Staphylococcus aureus and Bacillus megaterium, UDP-N-acetylmuramyl-pentapeptides (UDP-MurNAc-pentapeptides) accumulated at concentrations of ramoplanin close to the MIC, indicating that inhibition of peptidoglycan biosynthesis occurred after formation of cytoplasmic precursors. Susceptible bacteria bound or accumulated approximately 5 x 10(4) molecules of ramoplanin per cell, only 1/100th of the amount of vancomycin which binds to groups within peptidoglycan conforming to the pattern L-alpha alpha (amino acid)-D-alpha alpha-D-alpha alpha, suggesting that ramoplanin has a different target site. This was confirmed by in vitro studies involving a wall-membrane particulate fraction from Gaffkya homari in which peptidoglycan synthesis from UDP-MurNAc-tetrapeptide was inhibited by ramoplanin but not by vancomycin. The incorporation of peptidoglycan precursors into nascent peptidoglycan of a toluenized cell preparation of B. megaterium was inhibited by ramoplanin, indicating that the antibiotic acts at a step before transpeptidation. In vitro studies of a wall-membrane particulate fraction of B. megaterium indicated that ramoplanin did not prevent the formation of lipid intermediate I (undecaprenyl-P-P-MurNAc-pentapeptide) but inhibited the next reaction in which N-acetylglucosamine is transferred to that lipid intermediate. The high concentrations required to inhibit in vitro peptidoglycan-synthesizing systems probably reflect the high concentrations of target sites present. High concentrations of ramoplanin also damage certain properties of the cell membrane, but low concentrations only affected wall synthesis in intact bacteria without perturbing membrane function. These studies indicate that the primary target of ramoplanin is peptidoglycan biosynthesis and that the probable reaction inhibited is the N-acetylglucosaminyltransferase-catalyzed conversion of lipid intermediate I to lipid intermediate II.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_044

Impact of antibiotics with various target sites on the metabolome of Staphylococcus aureus. In this study, global intra- and extracellular metabolic profiles were exploited to investigate the impact of antibiotic compounds with different cellular targets on the metabolome of Staphylococcus aureus HG001. Primary metabolism was largely covered, yet uncommon staphylococcal metabolites were detected in the cytosol of S. aureus, including sedoheptulose-1,7-bisphosphate and the UDP-MurNAc-pentapeptide with an alanine-seryl residue. By comparing the metabolic profiles of unstressed and stressed staphylococcal cells in a time-dependent manner, we found far-ranging effects within the metabolome. For each antibiotic compound, accumulation as well as depletion of metabolites was detected, often comprising whole biosynthetic pathways, such as central carbon and amino acid metabolism and peptidoglycan, purine, and pyrimidine synthesis. Ciprofloxacin altered the pool of (deoxy)nucleotides as well as peptidoglycan precursors, thus linking stalled DNA and cell wall synthesis. Erythromycin tended to increase the amounts of intermediates of the pentose phosphate pathway and lysine. Fosfomycin inhibited the first enzymatic step of peptidoglycan synthesis, which was followed by decreased levels of peptidoglycan precursors but enhanced levels of substrates such as UDP-GlcNAc and alanine-alanine. In contrast, vancomycin and ampicillin inhibited the last stage of peptidoglycan construction on the outer cell surface. As a result, the amounts of UDP-MurNAc-peptides drastically increased, resulting in morphological alterations in the septal region and in an overall decrease in central metabolite levels. Moreover, each antibiotic affected intracellular levels of tricarboxylic acid cycle intermediates.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_045

Impact of antibiotics with various target sites on the metabolome of Staphylococcus aureus. In this study, global intra- and extracellular metabolic profiles were exploited to investigate the impact of antibiotic compounds with different cellular targets on the metabolome of Staphylococcus aureus HG001. Primary metabolism was largely covered, yet uncommon staphylococcal metabolites were detected in the cytosol of S. aureus, including sedoheptulose-1,7-bisphosphate and the UDP-MurNAc-pentapeptide with an alanine-seryl residue. By comparing the metabolic profiles of unstressed and stressed staphylococcal cells in a time-dependent manner, we found far-ranging effects within the metabolome. For each antibiotic compound, accumulation as well as depletion of metabolites was detected, often comprising whole biosynthetic pathways, such as central carbon and amino acid metabolism and peptidoglycan, purine, and pyrimidine synthesis. Ciprofloxacin altered the pool of (deoxy)nucleotides as well as peptidoglycan precursors, thus linking stalled DNA and cell wall synthesis. Erythromycin tended to increase the amounts of intermediates of the pentose phosphate pathway and lysine. Fosfomycin inhibited the first enzymatic step of peptidoglycan synthesis, which was followed by decreased levels of peptidoglycan precursors but enhanced levels of substrates such as UDP-GlcNAc and alanine-alanine. In contrast, vancomycin and ampicillin inhibited the last stage of peptidoglycan construction on the outer cell surface. As a result, the amounts of UDP-MurNAc-peptides drastically increased, resulting in morphological alterations in the septal region and in an overall decrease in central metabolite levels. Moreover, each antibiotic affected intracellular levels of tricarboxylic acid cycle intermediates.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_046

Impact of antibiotics with various target sites on the metabolome of Staphylococcus aureus. In this study, global intra- and extracellular metabolic profiles were exploited to investigate the impact of antibiotic compounds with different cellular targets on the metabolome of Staphylococcus aureus HG001. Primary metabolism was largely covered, yet uncommon staphylococcal metabolites were detected in the cytosol of S. aureus, including sedoheptulose-1,7-bisphosphate and the UDP-MurNAc-pentapeptide with an alanine-seryl residue. By comparing the metabolic profiles of unstressed and stressed staphylococcal cells in a time-dependent manner, we found far-ranging effects within the metabolome. For each antibiotic compound, accumulation as well as depletion of metabolites was detected, often comprising whole biosynthetic pathways, such as central carbon and amino acid metabolism and peptidoglycan, purine, and pyrimidine synthesis. Ciprofloxacin altered the pool of (deoxy)nucleotides as well as peptidoglycan precursors, thus linking stalled DNA and cell wall synthesis. Erythromycin tended to increase the amounts of intermediates of the pentose phosphate pathway and lysine. Fosfomycin inhibited the first enzymatic step of peptidoglycan synthesis, which was followed by decreased levels of peptidoglycan precursors but enhanced levels of substrates such as UDP-GlcNAc and alanine-alanine. In contrast, vancomycin and ampicillin inhibited the last stage of peptidoglycan construction on the outer cell surface. As a result, the amounts of UDP-MurNAc-peptides drastically increased, resulting in morphological alterations in the septal region and in an overall decrease in central metabolite levels. Moreover, each antibiotic affected intracellular levels of tricarboxylic acid cycle intermediates.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_047

Revealing fosfomycin primary effect on Staphylococcus aureus transcriptome: modulation of cell envelope biosynthesis and phosphoenolpyruvate induced starvation. BACKGROUND: Staphylococcus aureus is a highly adaptable human pathogen and there is a constant search for effective antibiotics. Fosfomycin is a potent irreversible inhibitor of MurA, an enolpyruvyl transferase that uses phosphoenolpyruvate as substrate. The goal of this study was to identify the pathways and processes primarily affected by fosfomycin at the genome-wide transcriptome level to aid development of new drugs. RESULTS: S. aureus ATCC 29213 cells were treated with sub-MIC concentrations of fosfomycin and harvested at 10, 20 and 40 minutes after treatment. S. aureus GeneChip statistical data analysis was complemented by gene set enrichment analysis. A visualization tool for mapping gene expression data into biological pathways was developed in order to identify the metabolic processes affected by fosfomycin. We have shown that the number of significantly differentially expressed genes in treated cultures increased with time and with increasing fosfomycin concentration. The target pathway - peptidoglycan biosynthesis - was upregulated following fosfomycin treatment. Modulation of transport processes, cofactor biosynthesis, energy metabolism and nucleic acid biosynthesis was also observed. CONCLUSIONS: Several pathways and genes downregulated by fosfomycin have been identified, in contrast to previously described cell wall active antibiotics, and was explained by starvation response induced by phosphoenolpyruvate accumulation. Transcriptomic profiling, in combination with meta-analysis, has been shown to be a valuable tool in determining bacterial response to a specific antibiotic.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_048

Inhibition of peptidoglycan biosynthesis by ramoplanin. Ramoplanin, a new lipoglycopeptide antibiotic, inhibits cell wall peptidoglycan biosynthesis in gram-positive bacteria. In both Staphylococcus aureus and Bacillus megaterium, UDP-N-acetylmuramyl-pentapeptides (UDP-MurNAc-pentapeptides) accumulated at concentrations of ramoplanin close to the MIC, indicating that inhibition of peptidoglycan biosynthesis occurred after formation of cytoplasmic precursors. Susceptible bacteria bound or accumulated approximately 5 x 10(4) molecules of ramoplanin per cell, only 1/100th of the amount of vancomycin which binds to groups within peptidoglycan conforming to the pattern L-alpha alpha (amino acid)-D-alpha alpha-D-alpha alpha, suggesting that ramoplanin has a different target site. This was confirmed by in vitro studies involving a wall-membrane particulate fraction from Gaffkya homari in which peptidoglycan synthesis from UDP-MurNAc-tetrapeptide was inhibited by ramoplanin but not by vancomycin. The incorporation of peptidoglycan precursors into nascent peptidoglycan of a toluenized cell preparation of B. megaterium was inhibited by ramoplanin, indicating that the antibiotic acts at a step before transpeptidation. In vitro studies of a wall-membrane particulate fraction of B. megaterium indicated that ramoplanin did not prevent the formation of lipid intermediate I (undecaprenyl-P-P-MurNAc-pentapeptide) but inhibited the next reaction in which N-acetylglucosamine is transferred to that lipid intermediate. The high concentrations required to inhibit in vitro peptidoglycan-synthesizing systems probably reflect the high concentrations of target sites present. High concentrations of ramoplanin also damage certain properties of the cell membrane, but low concentrations only affected wall synthesis in intact bacteria without perturbing membrane function. These studies indicate that the primary target of ramoplanin is peptidoglycan biosynthesis and that the probable reaction inhibited is the N-acetylglucosaminyltransferase-catalyzed conversion of lipid intermediate I to lipid intermediate II.

Which antibiotics target peptidoglycan biosynthesis?

571529efcb4ef8864c000001_049

Trichothiodystrophy: Photosensitive, TTD-P, TTD, Tay syndrome. Although the term, "trichothiodystrophy" (TTD) refers to the hair anomalies in this group of patients, this is a heterogeneous, multisystem disease in which any or every organ in the body may be affected. Neuroectodermal derived tissues are particularly likely to be involved. This term was introduced by Price et alin 1980 to designate patients with sulfur-deficient brittle hair, which they recognized as a marker for this complex disease and designated it as a "neuroectodermal symptom complex". Patients with TTD have brittle hair and nails (associated with reduced content ofcysteine-rich matrix proteins), ichthyotic skin and physical and mental growth retardation. Ichthyosis is usually apparent at birth but much less so after the first few weeks of life. Other frequently associated features include ocular cataracts, infections and maternal complications related to pregnancy. Atrophy of subcutaneous fat may also be present. TTD occurs in a pattern of inheritance consistent with an autosomal recessive condition. The disease is extremely heterogeneous in severity and extent, with some patients showing no neurological deficiency. Others show severe, multisystem disease. Many patients die at a young age, most commonly due to infectious disease. TTD is part of a more broadly defined group of diseases identified as IBIDS (ichthyosis, brittle hair, impaired intelligence, decreased fertility and short stature). Photosensitive cases are also identified as PIBIDS (photosensitivity with IBIDS). Cases without manifest ichthyosis are also identified as PBIDS. These syndromes defy rigorous definition because of clinical variation between patients. The original two cases were described by Tay in oriental siblings, whose parents were first cousins; thus the disease is also known as Tay syndrome. The hairs in patients with TTD have a distinctive, diagnostically useful appearance on polarized light microscopy consisting of alternating light and dark bands known as the "tiger tail" anomaly. Diagnosis may be confirmed by sulfur content analysis ofhair shafts, which shows decreased sulfur and cysteine content. Approximately half of patients with TTD have photosensitivity, which correlates with a nudeotide excision repair (NER) defect. These patients are designated as having trichothiodystrophy-photosensitive (TTDP). Non-photosensitivepatients are designated as having trichothiodystrophy-nonphotosensitive (TTDN). Skin cancer is very rare in sun-sensitive TTD.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_001

Trichothiodystrophy: Photosensitive, TTD-P, TTD, Tay syndrome. Although the term, "trichothiodystrophy" (TTD) refers to the hair anomalies in this group of patients, this is a heterogeneous, multisystem disease in which any or every organ in the body may be affected. Neuroectodermal derived tissues are particularly likely to be involved. This term was introduced by Price et alin 1980 to designate patients with sulfur-deficient brittle hair, which they recognized as a marker for this complex disease and designated it as a "neuroectodermal symptom complex". Patients with TTD have brittle hair and nails (associated with reduced content ofcysteine-rich matrix proteins), ichthyotic skin and physical and mental growth retardation. Ichthyosis is usually apparent at birth but much less so after the first few weeks of life. Other frequently associated features include ocular cataracts, infections and maternal complications related to pregnancy. Atrophy of subcutaneous fat may also be present. TTD occurs in a pattern of inheritance consistent with an autosomal recessive condition. The disease is extremely heterogeneous in severity and extent, with some patients showing no neurological deficiency. Others show severe, multisystem disease. Many patients die at a young age, most commonly due to infectious disease. TTD is part of a more broadly defined group of diseases identified as IBIDS (ichthyosis, brittle hair, impaired intelligence, decreased fertility and short stature). Photosensitive cases are also identified as PIBIDS (photosensitivity with IBIDS). Cases without manifest ichthyosis are also identified as PBIDS. These syndromes defy rigorous definition because of clinical variation between patients. The original two cases were described by Tay in oriental siblings, whose parents were first cousins; thus the disease is also known as Tay syndrome. The hairs in patients with TTD have a distinctive, diagnostically useful appearance on polarized light microscopy consisting of alternating light and dark bands known as the "tiger tail" anomaly. Diagnosis may be confirmed by sulfur content analysis ofhair shafts, which shows decreased sulfur and cysteine content. Approximately half of patients with TTD have photosensitivity, which correlates with a nudeotide excision repair (NER) defect. These patients are designated as having trichothiodystrophy-photosensitive (TTDP). Non-photosensitivepatients are designated as having trichothiodystrophy-nonphotosensitive (TTDN). Skin cancer is very rare in sun-sensitive TTD.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_002

Tay syndrome. Tay syndrome or IBIDS is a rare autosomal recessive genetic disorder characterized by congenital ichthyosis and abnormal brittle hair (trichothiodystrophy). Other features include photosensitivity, abnormal nails and multiple developmental defects affecting organs mainly derived from neuroectoderm. The exact prevalence of this condition is not known, but up to 1991, clinical data of 15 cases with IBIDS were published .We report a case of Tay syndrome with additional features of Duane's retraction syndrome and Perthes disease, which have not yet been reported in literature.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_003

Tay syndrome. Tay syndrome or IBIDS is a rare autosomal recessive genetic disorder characterized by congenital ichthyosis and abnormal brittle hair (trichothiodystrophy). Other features include photosensitivity, abnormal nails and multiple developmental defects affecting organs mainly derived from neuroectoderm. The exact prevalence of this condition is not known, but up to 1991, clinical data of 15 cases with IBIDS were published .We report a case of Tay syndrome with additional features of Duane's retraction syndrome and Perthes disease, which have not yet been reported in literature.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_004

[Trichothiodystrophy: PIBIDS syndrome]. Trichothiodystrophy comprises a heterogeneous group of autosomal recessive entities. This fact gives rise to different interrelated neuroectodermal disorders. From a structural point of view these features are the result of the low tissue sulfur content. We report a case of trichothiodystrophy initially classified as Tay syndrome that based on clinical features, complementary exams as well as on the disease evolution was labelled as PIBIDS syndrome.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_005

The central nervous system in Tay syndrome. Trichothiodystrophy (brittle sulfur-deficient hair) is a marker for several autosomal recessive neurocutaneous syndromes with neurological manifestations and mental retardation. In Tay syndrome, the trichothiodystrophy is accompanied by congenital ichthyosis, short stature, delayed physical and mental development and pyramidal tract signs with increase in muscular tone and brisk tendon reflexes. The pathogenesis of these neurological manifestations is not fully elucidated. We present a case of Tay syndrome in which a cranial MRI revealed an almost total lack of myelin within the cerebral hemispheres and a patchy hypomyelination of the cerebellum. In accordance, a strongly prolonged visual evoked response pointed to a dysfunction of the white matter in Tay syndrome.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_006

The central nervous system in Tay syndrome. Trichothiodystrophy (brittle sulfur-deficient hair) is a marker for several autosomal recessive neurocutaneous syndromes with neurological manifestations and mental retardation. In Tay syndrome, the trichothiodystrophy is accompanied by congenital ichthyosis, short stature, delayed physical and mental development and pyramidal tract signs with increase in muscular tone and brisk tendon reflexes. The pathogenesis of these neurological manifestations is not fully elucidated. We present a case of Tay syndrome in which a cranial MRI revealed an almost total lack of myelin within the cerebral hemispheres and a patchy hypomyelination of the cerebellum. In accordance, a strongly prolonged visual evoked response pointed to a dysfunction of the white matter in Tay syndrome.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_007

[What is new in genetically-induced hair diseases?]. A profound knowledge of specific genetically determined anomalies of the hair may be of considerable value in the diagnosis of genetic syndromes. We give a review of a few recent developments in the field of genetic hair diseases. For example, the brittle hair due to sulphur deficiency (trichothiodystrophy) is nowadays regarded as genetically heterogeneous; three different syndromes can be distinguished: BIDS syndrome, Tay syndrome, and PIBIDS syndrome. Polarization microscopy revealed a striking resemblance of the hair anomalies found in trichothiodystrophy syndromes and those in acrodermatitis enteropathica. This surprising result indicates similar pathophysiological mechanisms. The Comèl-Netherton syndrome--long regarded as representing two different diseases--has recently been recognized as a clinically variable, but genetically homogeneous syndrome, which is most likely based on a single mutation ("lumping"). Minor's sweat test allows the recognition of women heterozygous for X-linked hypohidrotic ectodermal dysplasia and may help to appreciate seemingly non-specific hair findings, such as diffuse alopecia.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_008

The Tay syndrome (congenital ichthyosis with trichothiodystrophy). We report a 5-year-old boy affected with the Tay syndrome, and give a review of 12 pertinent cases previously reported under various designations. The Tay syndrome is a distinct type of congenital ichthyosis characterized by a peculiar anomaly of hair growth which has been termed trichothiodystrophy. The hair shafts are extremely brittle, and they show alternating light and dark banding when examined microscopically between polarizing filters. Other features of this syndrome are low birth weight, short stature, mental retardation, delayed neuromuscular development and other CNS anomalies, dysplasia of nails, hypoplasia of subcutaneous fatty tissue, prematurely aged facial appearance, hypogonadism, cataracts, osteosclerosis, dysphonia, and increased susceptibility to infections. The syndrome is inherited as an autosomal recessive trait. We delineate the criteria for distinguishing this gene defect from other types of congenital ichthyosis associated with disturbed hair growth, as well as from other types of trichothiodystrophy which are not associated with ichthyosis.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_009

The Tay syndrome (congenital ichthyosis with trichothiodystrophy). We report a 5-year-old boy affected with the Tay syndrome, and give a review of 12 pertinent cases previously reported under various designations. The Tay syndrome is a distinct type of congenital ichthyosis characterized by a peculiar anomaly of hair growth which has been termed trichothiodystrophy. The hair shafts are extremely brittle, and they show alternating light and dark banding when examined microscopically between polarizing filters. Other features of this syndrome are low birth weight, short stature, mental retardation, delayed neuromuscular development and other CNS anomalies, dysplasia of nails, hypoplasia of subcutaneous fatty tissue, prematurely aged facial appearance, hypogonadism, cataracts, osteosclerosis, dysphonia, and increased susceptibility to infections. The syndrome is inherited as an autosomal recessive trait. We delineate the criteria for distinguishing this gene defect from other types of congenital ichthyosis associated with disturbed hair growth, as well as from other types of trichothiodystrophy which are not associated with ichthyosis.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_010

The Tay syndrome (congenital ichthyosis with trichothiodystrophy). We report a 5-year-old boy affected with the Tay syndrome, and give a review of 12 pertinent cases previously reported under various designations. The Tay syndrome is a distinct type of congenital ichthyosis characterized by a peculiar anomaly of hair growth which has been termed trichothiodystrophy. The hair shafts are extremely brittle, and they show alternating light and dark banding when examined microscopically between polarizing filters. Other features of this syndrome are low birth weight, short stature, mental retardation, delayed neuromuscular development and other CNS anomalies, dysplasia of nails, hypoplasia of subcutaneous fatty tissue, prematurely aged facial appearance, hypogonadism, cataracts, osteosclerosis, dysphonia, and increased susceptibility to infections. The syndrome is inherited as an autosomal recessive trait. We delineate the criteria for distinguishing this gene defect from other types of congenital ichthyosis associated with disturbed hair growth, as well as from other types of trichothiodystrophy which are not associated with ichthyosis.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_011

The Tay syndrome (congenital ichthyosis with trichothiodystrophy). We report a 5-year-old boy affected with the Tay syndrome, and give a review of 12 pertinent cases previously reported under various designations. The Tay syndrome is a distinct type of congenital ichthyosis characterized by a peculiar anomaly of hair growth which has been termed trichothiodystrophy. The hair shafts are extremely brittle, and they show alternating light and dark banding when examined microscopically between polarizing filters. Other features of this syndrome are low birth weight, short stature, mental retardation, delayed neuromuscular development and other CNS anomalies, dysplasia of nails, hypoplasia of subcutaneous fatty tissue, prematurely aged facial appearance, hypogonadism, cataracts, osteosclerosis, dysphonia, and increased susceptibility to infections. The syndrome is inherited as an autosomal recessive trait. We delineate the criteria for distinguishing this gene defect from other types of congenital ichthyosis associated with disturbed hair growth, as well as from other types of trichothiodystrophy which are not associated with ichthyosis.

List two common features of Tay syndrome.

53358cd2d6d3ac6a3400004e_012

Migratory potential of rheumatoid arthritis synovial fibroblasts: additional perspectives. Cell migration is a central part of physiological and pathophysiological processes including wound healing, immune defense, matrix remodeling and organ homeostasis. Different cell types have migratory potential including cells of the immune system and cells required in wound healing and tissue repair. These cells migrate locally through the tissue to the site of damage. The fibroblast is a central cell type of wound healing. In rheumatoid arthritis (RA), activated synovial fibroblasts (SFs) have the ability to invade joint cartilage, actively contributing to joint destruction in RA. Recently, RASFs have been shown to be able to migrate to non-affected areas and joints through the blood stream and to invade distant cartilage. RASFs most likely use similar mechanisms comparable to lymphocytes and tumor cells for long-distance and vascular trans-migration. Future experiments will address the goal to keep the transformed-appearing fibroblasts in the affected joints using therapeutical strategies that inhibit the pathophysiological changes of transformed-appearing RASFs but do not interfere with the physiological processes of 'normal' fibroblasts.

Which cell types are known to be driving Rheumatoid Arthritis?

52b2d405f828ad283c000009_001

The role and therapeutic implications of fibroblast-like synoviocytes in inflammation and cartilage erosion in rheumatoid arthritis. Fibroblast-like synoviocytes (FLS) are resident mesenchymal cells of synovial joints that have been recognized to play an increasingly important role in the pathogenesis of rheumatoid arthritis (RA). Activation of FLS in the setting of RA leads to the production of a broad array of cell surface and soluble mediators that help to recruit, retain, and activate both cells of the immune system and resident joint cells, leading to the promotion of ongoing inflammation and tissue destruction. The ability of FLS to stimulate both inflammation and tissue damage suggests that this cell type may be a unique target for the treatment of inflammatory arthritis. Greater understanding of how FLS are activated and how they interact with other cells in the RA synovium may provide insights that allow development of novel agents for RA therapy.

Which cell types are known to be driving Rheumatoid Arthritis?

52b2d405f828ad283c000009_002

Synovial fibroblasts: key players in rheumatoid arthritis. Rheumatoid arthritis (RA) is a chronic autoimmune-disease of unknown origin that primarily affects the joints and ultimately leads to their destruction. The involvement of immune cells is a general hallmark of autoimmune-related disorders. In this regard, macrophages, T cells and their respective cytokines play a pivotal role in RA. However, the notion that RA is a primarily T-cell-dependent disease has been strongly challenged during recent years. Rather, it has been understood that resident, fibroblast-like cells contribute significantly to the perpetuation of disease, and that they may even play a role in its initiation. These rheumatoid arthritis synovial fibroblasts (RASFs) constitute a quite unique cell type that distinguishes RA from other inflammatory conditions of the joints. A number of studies have demonstrated that RASFs show alterations in morphology and behaviour, including molecular changes in signalling cascades, apoptosis responses and in the expression of adhesion molecules as well as matrix-degrading enzymes. These changes appear to reflect a stable activation of RASFs, which occurs independently of continuous exogenous stimulation. As a consequence, RASFs are no longer considered passive bystanders but active players in the complex intercellular network of RA.

Which cell types are known to be driving Rheumatoid Arthritis?

52b2d405f828ad283c000009_003

Synovial fibroblasts: key players in rheumatoid arthritis. Rheumatoid arthritis (RA) is a chronic autoimmune-disease of unknown origin that primarily affects the joints and ultimately leads to their destruction. The involvement of immune cells is a general hallmark of autoimmune-related disorders. In this regard, macrophages, T cells and their respective cytokines play a pivotal role in RA. However, the notion that RA is a primarily T-cell-dependent disease has been strongly challenged during recent years. Rather, it has been understood that resident, fibroblast-like cells contribute significantly to the perpetuation of disease, and that they may even play a role in its initiation. These rheumatoid arthritis synovial fibroblasts (RASFs) constitute a quite unique cell type that distinguishes RA from other inflammatory conditions of the joints. A number of studies have demonstrated that RASFs show alterations in morphology and behaviour, including molecular changes in signalling cascades, apoptosis responses and in the expression of adhesion molecules as well as matrix-degrading enzymes. These changes appear to reflect a stable activation of RASFs, which occurs independently of continuous exogenous stimulation. As a consequence, RASFs are no longer considered passive bystanders but active players in the complex intercellular network of RA.

Which cell types are known to be driving Rheumatoid Arthritis?

52b2d405f828ad283c000009_004

Expression of HOXD9 in fibroblast-like synoviocytes from rheumatoid arthritis patients. The proteins of homeobox (HOX) genes are transcription regulators involved in cell type-specific differentiation and patterning of the body plan in vertebrates. Particularly, the HOXD family is involved in limb formation in mice and chicks. There is also some evidence that the HOXD9 gene, a member of the HOXD family, is involved in the pathology of rheumatoid arthritis (RA). The purpose of the present study was to determine if the HOXD9 protein was expressed in RA synovium and then to characterize the HOXD9-expressing cell. Western blotting and immunohistochemical analysis showed that the HOXD9 protein was expressed in the synovium from patients with RA, but not in those from patients with osteoarthritis or healthy individuals. The HOXD9-positive cells were localized in both the lining and sublining areas of the synovium. Furthermore, fluorescent double-staining showed that the HOXD9 protein was expressed in fibroblast-like synoviocytes (FLS). These findings not only indicate that the HOXD9 gene is exclusively expressed in the RA synovium but also suggest that the HOXD9 gene contributes to the pathology of rheumatoid arthritis through the FLS.

Which cell types are known to be driving Rheumatoid Arthritis?

52b2d405f828ad283c000009_005

Expression and regulation of CCL18 in synovial fluid neutrophils of patients with rheumatoid arthritis. Rheumatoid arthritis (RA) is characterized by the recruitment of leukocytes and the accumulation of inflammatory mediators within the synovial compartment. Release of the chemokine CCL18 has been widely attributed to antigen-presenting cells, including macrophages and dendritic cells. This study investigates the production of CCL18 in polymorphonuclear neutrophils (PMN), the predominant cell type recruited into synovial fluid (SF). Microarray analysis, semiquantitative and quantitative reverse transcriptase polymerase chain reaction identified SF PMN from patients with RA as a novel source for CCL18 in diseased joints. Highly upregulated expression of other chemokine genes was observed for CCL3, CXCL8 and CXCL10, whereas CCL21 was downregulated. The chemokine receptor genes were differentially expressed, with upregulation of CXCR4, CCRL2 and CCR5 and downregulation of CXCR1 and CXCR2. In cell culture experiments, expression of CCL18 mRNA in blood PMN was induced by tumor necrosis factor alpha, whereas synthesis of CCL18 protein required additional stimulation with a combination of IL-10 and vitamin D3. In comparison, recruited SF PMN from patients with RA were sensitized for CCL18 production, because IL-10 alone was sufficient to induce CCL18 release. These results suggest a release of the T cell-attracting CCL18 by PMN when recruited to diseased joints. However, its production is tightly regulated at the levels of mRNA expression and protein synthesis.

Which cell types are known to be driving Rheumatoid Arthritis?

52b2d405f828ad283c000009_006

Expression and regulation of CCL18 in synovial fluid neutrophils of patients with rheumatoid arthritis. Rheumatoid arthritis (RA) is characterized by the recruitment of leukocytes and the accumulation of inflammatory mediators within the synovial compartment. Release of the chemokine CCL18 has been widely attributed to antigen-presenting cells, including macrophages and dendritic cells. This study investigates the production of CCL18 in polymorphonuclear neutrophils (PMN), the predominant cell type recruited into synovial fluid (SF). Microarray analysis, semiquantitative and quantitative reverse transcriptase polymerase chain reaction identified SF PMN from patients with RA as a novel source for CCL18 in diseased joints. Highly upregulated expression of other chemokine genes was observed for CCL3, CXCL8 and CXCL10, whereas CCL21 was downregulated. The chemokine receptor genes were differentially expressed, with upregulation of CXCR4, CCRL2 and CCR5 and downregulation of CXCR1 and CXCR2. In cell culture experiments, expression of CCL18 mRNA in blood PMN was induced by tumor necrosis factor alpha, whereas synthesis of CCL18 protein required additional stimulation with a combination of IL-10 and vitamin D3. In comparison, recruited SF PMN from patients with RA were sensitized for CCL18 production, because IL-10 alone was sufficient to induce CCL18 release. These results suggest a release of the T cell-attracting CCL18 by PMN when recruited to diseased joints. However, its production is tightly regulated at the levels of mRNA expression and protein synthesis.

Which cell types are known to be driving Rheumatoid Arthritis?

52b2d405f828ad283c000009_007

Amiodarone-induced thyroid dysfunction in the Hong Kong Chinese population. OBJECTIVE: To determine the frequency, risk factors, clinical features, and management of amiodarone-induced thyroid dysfunctions. DESIGN: Retrospective study. SETTING: A regional hospital in Hong Kong. PATIENTS: Patients who had been prescribed amiodarone for at least 6 months from 1 October 2005 to 30 September 2007. RESULTS: A total of 390 patients (mean age, 70 years; standard deviation, 9 years; 54% male) with a median follow-up of 43 (interquartile range, 25-69) months were studied. Hypothyroidism developed in 87 (22%) of the patients (mean age, 72 years; standard deviation, 7 years; 56% male) and thyrotoxicosis in 24 (6%) of the patients (65 years; 11 years; 54% male). Increased baseline thyrotropin (thyroid-stimulating hormone) level appeared to be predictive of amiodarone-induced hypothyroidism, in which a thyroid-stimulating hormone level of 4 mIU/L or above was associated with a 4.7-fold increase in the risk (95% confidence interval, 1.9-11.7; P<0.001). Compared with those who remained euthyroid on amiodarone, thyrotoxicosis developed in younger patients. In these patients, the classical symptoms of thyroid dysfunction were frequently absent, although worsening of underlying arrhythmias, their cardiac condition, weight loss, and over-warfarinisation were suggestive of amiodarone-induced thyrotoxicosis. In both amiodarone-induced thyrotoxicosis and hypothyroidism, the disease course was benign. Patients with the former showed a good response to anti-thyroid drugs and steroid therapy. CONCLUSIONS: Amiodarone-induced thyroid dysfunction is common among our population. As the clinical presentations are usually vague and atypical, regular biochemical monitoring of thyroid function is warranted, particularly in patients with elevated baseline thyroid-stimulating hormone level. The disease course of amiodarone-induced thyrotoxicosis is usually benign and remits with timely administration of anti-thyroid medications, with or without corticosteroids.

Which drugs are utilized to treat amiodarone-induced thyroitoxicosis?

518cb4b5310faafe08000006_001

[Use of lithium carbonate for the treatment of amiodarone-induced thyrotoxicosis]. Among the amiodarone-induced thyroid dysfunctions, thyrotoxicosis is the most troublesome and with the highest rate of morbidity and mortality. Treatment consists in the use of a high dose of anti-thyroid drugs and steroids in an isolated form or in combination. Association of several other drugs have been proposed for the treatment of refractory cases. In this study we report the case of a 40 y.o. patient, with a history of idiopatic dilated miocardiopathy, who developed severe amioradone-induced thyrotoxicosis after heart transplantation. Since the patient did not respond to an initial treatment consisting of a high dose of anti-thyroid drugs combined with steroids, a low dose of lithium carbonate was added for a short period of time, which resulted in normalization of the thyroid function. In this case, the addition of lithium carbonate to the two other drugs resulted in a successful and safety therapy in controlling amiodarone-induced thyrotoxicosis.

Which drugs are utilized to treat amiodarone-induced thyroitoxicosis?

518cb4b5310faafe08000006_002

Lithium treatment in amiodarone-induced thyrotoxicosis. PURPOSE: Amiodarone hydrochloride is an iodine-rich drug effective in the control of various tachyarrhythmias. It is known to cause refractory to thyrotoxicosis, which usually does not respond to regular antithyroid drugs. Lithium bicarbonate is a medication used to treat psychiatric disorders; it also influences thyroid production and release of hormones. We tried it in combination with propylthiouracil (PTU) for the treatment of amiodarone-induced thyrotoxicosis. PATIENTS AND METHODS: Twenty-one patients were studied. The first group (n = 5) was treated by amiodarone withdrawal only. The second group (n = 7) received PTU (300 to 600 mg), and the third (n = 9) PTU (300 mg) and lithium (900 to 1350 mg) daily. Patient selection was not randomized. The PTU + lithium group had more severe symptoms and signs of thyrotoxicosis, as well as thyroxine levels at least 50% above the upper limit of normal. They also had been on a longer course of amiodarone treatment (34.3 +/- 11.9 months) than the PTU-only (11.4 +/- 7.5) and the no-treatment (7.8 +/- 4.2) groups. RESULTS: While there was no difference between the first two groups in time until recovery (10.6 +/- 4.0 versus 11.6 +/- 0.5 weeks, respectively), the group receiving lithium normalized their thyroid function tests in only 4.3 +/- 0.5 weeks (P < 0.01 versus both other groups). T3 levels normalized even earlier-by 3 weeks of lithium treatment. No adverse effects of lithium were encountered, and the medication was stopped 4 to 6 weeks after achieving a normal clinical and biochemical state. CONCLUSIONS: We conclude that lithium is a useful and safe medication for treatment of iodine-induced thyrotoxicosis caused by amiodarone. We would reserve this treatment for severe cases only. Further studies are needed to find out whether in patients with this troublesome complication lithium therapy could permit continuation of amiodarone treatment.

Which drugs are utilized to treat amiodarone-induced thyroitoxicosis?

518cb4b5310faafe08000006_003

Two cases of amiodarone-induced thyrotoxicosis successfully treated with a short course of antithyroid drugs while amiodarone was continued. Two patients with amiodarone-induced thyrotoxicosis were treated successfully with potassium perchlorate and carbimazole while treatment with amiodarone was continued. These antithyroid drugs were stopped after the patients had became clinically and biochemically euthyroid. During follow up, when treatment with amiodarone continued, thyrotoxicosis did not recur. Amiodarone-induced thyrotoxicosis seems to be a transient condition that can be treated successfully with a short course of antithyroid drugs without stopping amiodarone treatment.

Which drugs are utilized to treat amiodarone-induced thyroitoxicosis?

518cb4b5310faafe08000006_004

BCL11B is up-regulated by EWS/FLI and contributes to the transformed phenotype in Ewing sarcoma. The EWS/FLI translocation product is the causative oncogene in Ewing sarcoma and acts as an aberrant transcription factor. EWS/FLI dysregulates gene expression during tumorigenesis by abnormally activating or repressing genes. The expression levels of thousands of genes are affected in Ewing sarcoma, however, it is unknown which of these genes contribute to the transformed phenotype. Here we characterize BCL11B as an up-regulated EWS/FLI target that is necessary for the maintenance of transformation in patient derived Ewing sarcoma cells lines. BCL11B, a zinc finger transcription factor, acts as a transcriptional repressor in Ewing's sarcoma and contributes to the EWS/FLI repressed gene signature. BCL11B repressive activity is mediated by the NuRD co-repressor complex. We further demonstrate that re-expression of SPRY1, a repressed target of BCL11B, limits the transformation capacity of Ewing sarcoma cells. These data define a new pathway downstream of EWS/FLI required for oncogenic maintenance in Ewing sarcoma.

Which are the genes thought to be regulated by EWS/FLI?

552faa43bc4f83e828000004_001

BCL11B is up-regulated by EWS/FLI and contributes to the transformed phenotype in Ewing sarcoma. The EWS/FLI translocation product is the causative oncogene in Ewing sarcoma and acts as an aberrant transcription factor. EWS/FLI dysregulates gene expression during tumorigenesis by abnormally activating or repressing genes. The expression levels of thousands of genes are affected in Ewing sarcoma, however, it is unknown which of these genes contribute to the transformed phenotype. Here we characterize BCL11B as an up-regulated EWS/FLI target that is necessary for the maintenance of transformation in patient derived Ewing sarcoma cells lines. BCL11B, a zinc finger transcription factor, acts as a transcriptional repressor in Ewing's sarcoma and contributes to the EWS/FLI repressed gene signature. BCL11B repressive activity is mediated by the NuRD co-repressor complex. We further demonstrate that re-expression of SPRY1, a repressed target of BCL11B, limits the transformation capacity of Ewing sarcoma cells. These data define a new pathway downstream of EWS/FLI required for oncogenic maintenance in Ewing sarcoma.

Which are the genes thought to be regulated by EWS/FLI?

552faa43bc4f83e828000004_002

BCL11B is up-regulated by EWS/FLI and contributes to the transformed phenotype in Ewing sarcoma. The EWS/FLI translocation product is the causative oncogene in Ewing sarcoma and acts as an aberrant transcription factor. EWS/FLI dysregulates gene expression during tumorigenesis by abnormally activating or repressing genes. The expression levels of thousands of genes are affected in Ewing sarcoma, however, it is unknown which of these genes contribute to the transformed phenotype. Here we characterize BCL11B as an up-regulated EWS/FLI target that is necessary for the maintenance of transformation in patient derived Ewing sarcoma cells lines. BCL11B, a zinc finger transcription factor, acts as a transcriptional repressor in Ewing's sarcoma and contributes to the EWS/FLI repressed gene signature. BCL11B repressive activity is mediated by the NuRD co-repressor complex. We further demonstrate that re-expression of SPRY1, a repressed target of BCL11B, limits the transformation capacity of Ewing sarcoma cells. These data define a new pathway downstream of EWS/FLI required for oncogenic maintenance in Ewing sarcoma.

Which are the genes thought to be regulated by EWS/FLI?

552faa43bc4f83e828000004_003

GSTM4 is a microsatellite-containing EWS/FLI target involved in Ewing's sarcoma oncogenesis and therapeutic resistance. Ewing's sarcoma is a malignant bone-associated tumor of children and young adults. Most cases of Ewing's sarcoma express the EWS/FLI fusion protein. EWS/FLI functions as an aberrant ETS-type transcription factor and serves as the master regulator of Ewing's sarcoma-transformed phenotype. We recently showed that EWS/FLI regulates one of its key targets, NR0B1, through a GGAA-microsatellite in its promoter. Whether other critical EWS/FLI targets are also regulated by GGAA-microsatellites was unknown. In this study, we combined transcriptional analysis, whole genome localization data, and RNA interference knockdown to identify glutathione S-transferase M4 (GSTM4) as a critical EWS/FLI target gene in Ewing's sarcoma. We found that EWS/FLI directly binds the GSTM4 promoter, and regulates GSTM4 expression through a GGAA-microsatellite in its promoter. Reduction of GSTM4 levels caused a loss of oncogenic transformation. Furthermore, reduction of GSTM4 resulted in an increased sensitivity of Ewing's sarcoma cells to chemotherapeutic agents, suggesting a role for this protein in drug resistance. Consistent with this hypothesis, patients with Ewing's sarcoma whose tumors had higher levels of GSTM4 expression had worse outcomes than those with lower expression levels. These data show that GSTM4 contributes to the cancerous behavior of Ewing's sarcoma and define a wider role for GGAA-microsatellites in EWS/FLI function than previously appreciated. These data also suggest a novel therapeutic resistance mechanism, in which the central oncogenic abnormality directly regulates a resistance gene.

Which are the genes thought to be regulated by EWS/FLI?

552faa43bc4f83e828000004_004

GSTM4 is a microsatellite-containing EWS/FLI target involved in Ewing's sarcoma oncogenesis and therapeutic resistance. Ewing's sarcoma is a malignant bone-associated tumor of children and young adults. Most cases of Ewing's sarcoma express the EWS/FLI fusion protein. EWS/FLI functions as an aberrant ETS-type transcription factor and serves as the master regulator of Ewing's sarcoma-transformed phenotype. We recently showed that EWS/FLI regulates one of its key targets, NR0B1, through a GGAA-microsatellite in its promoter. Whether other critical EWS/FLI targets are also regulated by GGAA-microsatellites was unknown. In this study, we combined transcriptional analysis, whole genome localization data, and RNA interference knockdown to identify glutathione S-transferase M4 (GSTM4) as a critical EWS/FLI target gene in Ewing's sarcoma. We found that EWS/FLI directly binds the GSTM4 promoter, and regulates GSTM4 expression through a GGAA-microsatellite in its promoter. Reduction of GSTM4 levels caused a loss of oncogenic transformation. Furthermore, reduction of GSTM4 resulted in an increased sensitivity of Ewing's sarcoma cells to chemotherapeutic agents, suggesting a role for this protein in drug resistance. Consistent with this hypothesis, patients with Ewing's sarcoma whose tumors had higher levels of GSTM4 expression had worse outcomes than those with lower expression levels. These data show that GSTM4 contributes to the cancerous behavior of Ewing's sarcoma and define a wider role for GGAA-microsatellites in EWS/FLI function than previously appreciated. These data also suggest a novel therapeutic resistance mechanism, in which the central oncogenic abnormality directly regulates a resistance gene.

Which are the genes thought to be regulated by EWS/FLI?

552faa43bc4f83e828000004_005

GSTM4 is a microsatellite-containing EWS/FLI target involved in Ewing's sarcoma oncogenesis and therapeutic resistance. Ewing's sarcoma is a malignant bone-associated tumor of children and young adults. Most cases of Ewing's sarcoma express the EWS/FLI fusion protein. EWS/FLI functions as an aberrant ETS-type transcription factor and serves as the master regulator of Ewing's sarcoma-transformed phenotype. We recently showed that EWS/FLI regulates one of its key targets, NR0B1, through a GGAA-microsatellite in its promoter. Whether other critical EWS/FLI targets are also regulated by GGAA-microsatellites was unknown. In this study, we combined transcriptional analysis, whole genome localization data, and RNA interference knockdown to identify glutathione S-transferase M4 (GSTM4) as a critical EWS/FLI target gene in Ewing's sarcoma. We found that EWS/FLI directly binds the GSTM4 promoter, and regulates GSTM4 expression through a GGAA-microsatellite in its promoter. Reduction of GSTM4 levels caused a loss of oncogenic transformation. Furthermore, reduction of GSTM4 resulted in an increased sensitivity of Ewing's sarcoma cells to chemotherapeutic agents, suggesting a role for this protein in drug resistance. Consistent with this hypothesis, patients with Ewing's sarcoma whose tumors had higher levels of GSTM4 expression had worse outcomes than those with lower expression levels. These data show that GSTM4 contributes to the cancerous behavior of Ewing's sarcoma and define a wider role for GGAA-microsatellites in EWS/FLI function than previously appreciated. These data also suggest a novel therapeutic resistance mechanism, in which the central oncogenic abnormality directly regulates a resistance gene.

Which are the genes thought to be regulated by EWS/FLI?

552faa43bc4f83e828000004_006