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22530842 | The experience accumulated in cardiac cell therapy suggests that regeneration of extensively necrotic myocardial areas is unlikely to be achieved by the sole paracrine effects of the grafted cells but rather requires the conversion of these cells into cardiomyocytes featuring the capacity to substitute for those which have been irreversibly lost. In this setting, the use of human pluripotent embryonic stem cells has a strong rationale. The experimental results obtained in animal models of myocardial infarction are encouraging. However, the switch to clinical applications still requires to address some critical issues, among which the optimization of the cardiac specification of the embryonic stem cells, the purification of the resulting progenitor cells so as to graft a purified population devoid from any contamination by residual pluripotent cells which carry the risk of tumorigenesis, and the control of the expected allogeneic rejection by clinically acceptable methods. If the solution to these problems is a prerequisite, the therapeutic success of this approach will also depend on the capacity to efficiently transfer the cells to the target tissue, to keep them alive once engrafted, and to allow them to spatially organize in such a way that they can contribute to the contractile function of the heart. |
22543403 | The exploration of brain epigenomes, which consist of various types of DNA methylation and covalent histone modifications, is providing new and unprecedented insights into the mechanisms of neural development, neurological disease and aging. Traditionally, chromatin defects in the brain were considered static lesions of early development that occurred in the context of rare genetic syndromes, but it is now clear that mutations and maladaptations of the epigenetic machinery cover a much wider continuum that includes adult-onset neurodegenerative disease. Here, we describe how recent advances in neuroepigenetics have contributed to an improved mechanistic understanding of developmental and degenerative brain disorders, and we discuss how they could influence the development of future therapies for these conditions. |
22549449 | Adult neurogenesis has been shown to be regulated by a multitude of extracellular cues, including hormones, growth factors, and neurotransmitters. The cholinergic system of the basal forebrain is one of the key transmitter systems for learning and memory. Because adult neurogenesis has been implicated in cognitive performance, the present work aims at defining the role of cholinergic input for adult neurogenesis by using an immunotoxic lesion approach. The immunotoxin 192IgG-saporin was infused into the lateral ventricle of adult rats to selectively lesion cholinergic neurons of the cholinergic basal forebrain (CBF), which project to the two main regions of adult neurogenesis: the dentate gyrus and the olfactory bulb. Five weeks after lesioning, neurogenesis, defined by the number of cells colocalized for bromodeoxyuridine (BrdU) and the neuronal nuclei marker NeuN, declined significantly in the granule cell layers of the dentate gyrus and olfactory bulb. Furthermore, immunotoxic lesions to the CBF led to increased numbers of apoptotic cells specifically in the subgranular zone, the progenitor region of the dentate gyrus, and within the periglomerular layer of the olfactory bulb. We propose that the cholinergic system plays a survival-promoting role for neuronal progenitors and immature neurons within regions of adult neurogenesis, similar to effects observed previously during brain development. As a working hypothesis, neuronal loss within the CBF system leads not only to cognitive deficits but may also alter on a cellular level the functionality of the dentate gyrus, which in turn may aggravate cognitive deficits. |
22551259 | Epigenetic mechanisms regulate gene expression, influencing protein levels and ultimately shaping phenotypes during life. However, both stochastic epigenetic variations and environmental reprogramming of the epigenome might influence neurodevelopment and ageing, and this may contribute to the origins of mental ill-health. Studying the role of epigenetic mechanisms is challenging, as genotype-, tissue- and cell type-dependent epigenetic changes have to be taken into account, while the nature of mental disorders also poses significant challenges for linking them with biological profiles. In this chapter, we summarise the current evidence suggesting the role of DNA methylation as a key epigenetic mechanism in major depressive disorder. |
22613657 | Allogeneic haematopoietic stem cell transplantation is used to treat a variety of disorders, but its efficacy is limited by the occurrence of graft-versus-host disease (GVHD). The past decade has brought impressive advances in our understanding of the role of stimulatory and suppressive elements of the adaptive and innate immune systems from both the donor and the host in GVHD pathogenesis. New insights from basic immunology, preclinical models and clinical studies have led to novel approaches for prevention and treatment. This Review highlights the recent advances in understanding the pathophysiology of GVHD and its treatment, with a focus on manipulations of the immune system that are amenable to clinical application. |
22623275 | Members of the conserved family of eukaryotic RNA-dependent RNA polymerases (Rdrs) synthesize double-stranded RNA (dsRNA) intermediates in diverse pathways of small RNA (sRNA) biogenesis and RNA-mediated silencing. Rdr-dependent pathways of sRNA production are poorly characterized relative to Rdr-independent pathways, and the Rdr enzymes themselves are poorly characterized relative to their viral RNA-dependent RNA polymerase counterparts. We previously described a physical and functional coupling of the Tetrahymena thermophila Rdr, Rdr1, and a Dicer enzyme, Dcr2, in the production of approximately 24-nucleotide (nt) sRNA in vitro. Here we characterize the endogenous complexes that harbor Rdr1, termed RDRCs. Distinct RDRCs assemble to contain Rdr1 and subsets of the total of four tightly Rdr1-associated proteins. Of particular interest are two RDRC subunits, Rdn1 and Rdn2, which possess noncanonical ribonucleotidyl transferase motifs. We show that the two Rdn proteins are uridine-specific polymerases of separate RDRCs. Two additional RDRC subunits, Rdf1 and Rdf2, are present only in RDRCs containing Rdn1. Rdr1 catalytic activity is retained in RDRCs purified from cell extracts lacking any of the nonessential RDRC subunits (Rdn2, Rdf1, Rdf2) or if the RDRC harbors a catalytically inactive Rdn. However, specific disruption of each RDRC imposes distinct loss-of-function consequences at the cellular level and has a differential impact on the accumulation of specific 23-24-nt sRNA sequences in vivo. The biochemical and biological phenotypes of RDRC subunit disruption reveal a previously unanticipated complexity of Rdr-dependent sRNA biogenesis in vivo. |
22635278 | From April 1986 to September 2000, 122 MRCC patients were treated by monthly intralymphatic injections (containing a mean of 573 IL-2 U and 26 x 10(6) LAK cells) and i.m. administration of IFN and TF; 71 patients also received a 3-day cycle of monthly IL-2 inhalations with a mean of 998 daily U. MRCC cases not treated by immunotherapy (n = 89) represent our historical controls. Adverse clinical side effects related to treatment were negligible. CR (n = 11) and PR (n = 13) were noticed in 24/122 patients. Of 24 responding patients, 17 resumed progression, whereas 7 remain in remission 11-69 months later. The overall median survival of treated patients (28 months) was 3.5-fold higher than the median survival of historical controls (7.5 months), and a Kaplan-Meier curve showed 25% survival 11 years after the beginning of immunotherapy. Apparently, the addition of IL-2 by inhalation improved survival. The present immunotherapy protocol appears to be efficacious, safe, devoid of adverse side effects, far less costly than others and able to offer a good quality of life to MRCC patients; if confirmed in a multicenter trial, it could set the basis for developing low-dose immunomodulatory treatments. |
22647695 | Autoreactive T cell responses have a crucial role in central nervous system (CNS) diseases such as multiple sclerosis. Recent data indicate that CNS autoimmunity can be mediated by two distinct lineages of CD4+ T cells that are defined by the production of either interferon-γ or interleukin-17. The activity of these CD4+ T cell subsets within the CNS influences the pathology and clinical course of disease. New animal models show that myelin-specific CD8+ T cells can also mediate CNS autoimmunity. This Review focuses on recent progress in delineating the pathogenic mechanisms, regulation and interplay between these different T cell subsets in CNS autoimmunity. |
22674621 | Farnesoid X receptor (FXR), a bile-acid-activated member of the nuclear receptor superfamily, is essential in regulating bile-acid, cholesterol, and triglyceride homeostasis. Disruption of the FXR gene in mice results in a proatherosclerotic lipid profile with increased serum cholesterols and triglycerides. However, the role of FXR in foam-cell formation and atherosclerosis development remains unclear. The current study showed that the peritoneal macrophages isolated from FXR-null mice took up less oxidized LDL-cholesterol (oxLDL-C), which was accompanied by a marked reduction in CD36 expression in these cells. This result appears to be FXR-independent, as FXR was not detected in the peritoneal macrophages. To assess to what extent FXR modulates atherosclerosis development, FXR/ApoE double-null mice were generated. Female mice were used for atherosclerosis analysis. Compared to ApoE-null mice, the FXR/ApoE double-null mice were found to have less atherosclerotic lesion area in the aorta, despite a further increase in the serum cholesterols and triglycerides. Our results indicate that disruption of the FXR gene could attenuate atherosclerosis development, most likely resulting from reduced oxLDL-C uptake by macrophages. Our study cautions the use of serum lipid levels as a surrogate marker to determine the efficiency of FXR modulators in treating hyperlipidemia. |
22688699 | OBJECT Awake craniotomy was performed as the standard surgical approach to supratentorial intraaxial tumors, regardless of the involvement of eloquent cortex, in a prospective trial of 200 patients surgically treated by the same surgeon at a single institution. METHODS Patient presentations, comorbid conditions, tumor locations, and the histological characteristics of lesions were recorded. Brain mapping was possible in 195 (97.5%) of 200 patients. The total number of patients sustaining complications was 33 for an overall complication rate of 16.5%. There were two deaths in this series, for a mortality rate of 1%. New postoperative neurological deficits were seen in 13% of the patients, but these were permanent in only 4.5% of them. Complication rates were higher in patients who had gliomas or preoperative neurological deficits and in those who had undergone prior radiation therapy or surgery. No patient who entered the operating room neurologically intact sustained a permanent neurological deficit postoperatively. Of the most recent 50 patients treated, three (6%) required a stay in the intensive care unit, and the median total hospital stay was 1 day. CONCLUSIONS Use of awake craniotomy can result in a considerable reduction in resource utilization without compromising patient care by minimizing intensive care time and total hospital stay. Awake craniotomy is a practical and effective standard surgical approach to supratentorial tumors with a low complication rate, and provides an excellent alternative to craniotomy performed with the patient in the state of general anesthesia because it allows the opportunity for brain mapping and avoids general anesthesia. |
22696649 | How the number of immune cells recruited to sites of infection is determined and adjusted to differences in the cellular stoichiometry between host and pathogen is unknown. Here, we have uncovered a role for reactive oxygen species (ROS) as sensors of microbe size. By sensing the differential localization of ROS generated in response to microbes of different size, neutrophils tuned their interleukin (IL)-1β expression via the selective oxidation of NF-κB, in order to implement distinct inflammatory programs. Small microbes triggered ROS intracellularly, suppressing IL-1β expression to limit neutrophil recruitment as each phagocyte eliminated numerous pathogens. In contrast, large microbes triggered ROS extracellularly, amplifying IL-1β expression to recruit numerous neutrophils forming cooperative clusters. Defects in ROS-mediated microbe size sensing resulted in large neutrophil infiltrates and clusters in response to small microbes that contribute to inflammatory disease. These findings highlight the impact of ROS localization on signal transduction. |
22703082 | Infection with Helicobacter pylori (H. pylori) is a risk factor for the development of gastric cancer. Here we show that infection of gastric epithelial cells with 'cag' pathogenicity island (cagPAI)-positive H. pylori induced aberrant expression of activation-induced cytidine deaminase (AID), a member of the cytidine-deaminase family that acts as a DNA- and RNA-editing enzyme, via the IκB kinase–dependent nuclear factor-κB activation pathway. H. pylori–mediated upregulation of AID resulted in the accumulation of nucleotide alterations in the TP53 tumor suppressor gene in gastric cells in vitro. Our findings provide evidence that aberrant AID expression caused by H. pylori infection might be a mechanism of mutation accumulation in the gastric mucosa during H. pylori–associated gastric carcinogenesis. |
22705234 | The African green monkey (AGM) is one of many African species endemically infected with simian immunodeficiency virus (SIV). Like the other natural hosts, AGMs do not succumb to AIDS and understanding the basis for this resistance to disease progression would be of enormous theoretical and practical importance. Early efforts by our group that concentrated on identifying immune mechanisms presumed to keep the virus under control failed to find any obvious candidates. The presumption of virus control was invalidated by the finding that SIVagm replicates in AGMs with the same vigor as HIV-1 does in humans. Focus therefore shifted to identifying possible immunopathologic features present in disease susceptible hosts but absent in the AGM natural host. The apparent immunologic tolerance of AGMs to the SIVagm core protein led to the development of a hypothesis implicating anti-Gag antibodies in the formation of immune complexes, virus trapping in the lymph nodes and immune dysfunction. The idea proved difficult to test in vivo and present work focuses on the possibility that Gag tolerance at the T-cell level plays an important role in preventing the catastrophic demise of the immune system characteristic of immunodeficiency virus infection of the heterologous primate host. |
22707413 | This article describes the development and validation of the S-LANSS score, a self-report version of the Leeds Assessment of Neuropathic Symptoms and Signs pain scale. The S-LANSS aims to identify pain of predominantly neuropathic origin, as distinct from nociceptive pain, without the need for clinical examination. Two hundred patients with chronic pain were asked to complete the S-LANSS unaided. A researcher then administered the S-LANSS scale and the Neuropathic Pain Scale (NPS) in interview format. An independent clinician determined the pain type (neuropathic versus nociceptive) and rated his or her certainty about diagnosis. The S-LANSS scale was also incorporated into a chronic pain questionnaire that was sent to 160 community patients and 150 newly referred patients waiting for pain clinic assessment. The S-LANSS scale correctly identified 75% of pain types when self-completed and 80% when used in interview format. Sensitivity for self-completed S-LANSS scores ranged from 74% to 78%, depending on the cutoff score. There were significant associations between NPS items and total score with S-LANSS score. In the postal survey, completed questionnaires were returned by 57% of patients (n = 174). Internal consistency and convergent validity of the survey S-LANSS scores were confirmed. The findings support the S-LANSS scale as a valid and reliable self-report instrument for identifying neuropathic pain and it is also acceptable for use in postal survey research. Establishing valid measures of symptoms and signs in neuropathic pain will allow standardized comparisons with other investigational measures. This might lead to new insights into the relationship between pathophysiologic mechanisms and clinical manifestations of pain. |
22711954 | OBJECTIVE Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. DESIGN Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30% of the trial); analysis of funnel plots from 37 meta-analyses identified from a hand search of four leading general medicine journals 1993-6 and 38 meta-analyses from the second 1996 issue of the Cochrane Database of Systematic Reviews. MAIN OUTCOME MEASURE Degree of funnel plot asymmetry as measured by the intercept from regression of standard normal deviates against precision. RESULTS In the eight pairs of meta-analysis and large trial that were identified (five from cardiovascular medicine, one from diabetic medicine, one from geriatric medicine, one from perinatal medicine) there were four concordant and four discordant pairs. In all cases discordance was due to meta-analyses showing larger effects. Funnel plot asymmetry was present in three out of four discordant pairs but in none of concordant pairs. In 14 (38%) journal meta-analyses and 5 (13%) Cochrane reviews, funnel plot asymmetry indicated that there was bias. CONCLUSIONS A simple analysis of funnel plots provides a useful test for the likely presence of bias in meta-analyses, but as the capacity to detect bias will be limited when meta-analyses are based on a limited number of small trials the results from such analyses should be treated with considerable caution. |
22712546 | Over the past years, plenty of evidence has emerged illustrating how metabolism supports many aspects of cellular function and how metabolic reprogramming can drive cell differentiation and fate. Here, we present a method to assess the metabolic configuration of single cells within their native tissue microenvironment via the visualization and quantification of multiple enzymatic activities measured at saturating substrate conditions combined with subsequent cell type identification. After careful validation of the approach and to demonstrate its potential, we assessed the intracellular metabolic configuration of different human immune cell populations in healthy and tumor colon tissue. Additionally, we analyzed the intercellular metabolic relationship between cancer cells and cancer-associated fibroblasts in a breast cancer tissue array. This study demonstrates that the determination of metabolic configurations in single cells could be a powerful complementary tool for every researcher interested to study metabolic networks in situ. |
22730024 | OBJECTIVE To assess the antihypertensive efficacy of olmesartan medoxomil and ramipril on 24-h ambulatory blood pressure (ABP) in elderly hypertensive patients by pooled data analysis of two studies with identical designs (one Italian, one European). METHODS After a 2-week placebo wash-out 1453 elderly hypertensive patients (65-89 years; sitting office DBP 90-109 mmHg and/or sitting office SBP 140-179 mmHg) were randomized to a 12-week double-blind treatment with olmesartan medoxomil 10 mg or ramipril 2.5 mg once-daily, up-titrated (20 and 40 mg olmesartan medoxomil; 5 and 10 mg ramipril) after 2 and 6 weeks in patients without normalized office BP. 24-h ABP was recorded at randomization and after 12 weeks. RESULTS In 715 patients with valid baseline and end-of-treatment recordings baseline-adjusted 24-h SBP and DBP reductions were greater with olmesartan medoxomil (n = 356) than with ramipril (n = 359) [between-treatment differences and 95% confidence interval (CI), SBP: 2.2 (3.8, 0.6), P = 0.006; DBP: 1.3 (2.2, 0.3), P = 0.009]. Olmesartan medoxomil showed larger BP reductions in the last 6 h from the dosing interval and higher smoothness indices than ramipril. Olmesartan medoxomil reduced the SBP morning rise [-2.8 (-4.9, -0.8) mmHg], whereas ramipril did not [+1.5 (-0.6, +3.6) mmHg; P = 0.004 between-treatments]. Five hundred and eighty-two patients with sustained hypertension (office and 24-h ambulatory hypertension) showed the largest antihypertensive effect, with between-treatment differences still in favor of olmesartan medoxomil [SBP: 2.1 (3.9, 0.4), P = 0.019; DBP: 1.2 (2.3, 0.1), P = 0.032]. CONCLUSIONS Olmesartan medoxomil provides a more effective and sustained 24-h BP control than ramipril in elderly hypertensive patients, particularly in the hours farthest from last intake. |
22767022 | WAVE2 belongs to a family of proteins that mediates actin reorganization by relaying signals from Rac to the Arp2/3 complex, resulting in lamellipodia protrusion. WAVE2 displays Arp2/3-dependent actin nucleation activity in vitro, and does not bind directly to Rac. Instead, it forms macromolecular complexes that have been reported to exert both positive and negative modes of regulation. How these complexes are assembled, localized and activated in vivo remains to be established. Here we use tandem mass spectrometry to identify an Abi1-based complex containing WAVE2, Nap1 (Nck-associated protein) and PIR121. Abi1 interacts directly with the WHD domain of WAVE2, increases WAVE2 actin polymerization activity and mediates the assembly of a WAVE2–Abi1–Nap1–PIR121 complex. The WAVE2–Abi1–Nap1–PIR121 complex is as active as the WAVE2–Abi1 sub-complex in stimulating Arp2/3, and after Rac activation it is re-localized to the leading edge of ruffles in vivo. Consistently, inhibition of Abi1 by RNA interference (RNAi) abrogates Rac-dependent lamellipodia protrusion. Thus, Abi1 orchestrates the proper assembly of the WAVE2 complex and mediates its activation at the leading edge in vivo. |
22791348 | Dendritic cells (DCs) form a remarkable cellular network that shapes adaptive immune responses according to peripheral cues. After four decades of research, we now know that DCs arise from a hematopoietic lineage distinct from other leukocytes, establishing the DC system as a unique hematopoietic branch. Recent work has also established that tissue DCs consist of developmentally and functionally distinct subsets that differentially regulate T lymphocyte function. This review discusses major advances in our understanding of the regulation of DC lineage commitment, differentiation, diversification, and function in situ. |
22800314 | Interleukin-15 (IL-15) is a cytokine produced in the normal brain that acts on its specific receptor IL-15Rα and co-receptors IL-2Rβ and IL-2Rγ in neuronal cells. The functions of the cerebral IL-15 system, however, are not yet clear. To test the hypothesis that IL-15Rα regulates metabolic activity and body temperature, we quantified the specific metabolic phenotype of IL-15Rα knockout mice. These normal-appearing mice were leaner with lower fat composition. During the entire circadian cycle, the knockout mice had a significantly higher acrophase in locomotor activity and heat dissipation. During the light phase, there was significantly greater food intake, oxygen consumption, and carbon dioxide production. The difference in the dark and light phases suggests that IL-15Rα participates in circadian rhythm regulation. The higher oxygen consumption in the light phase indicates adaptive thermogenesis in the knockout mice. The body temperature of the receptor knockout mice was significantly higher than the control in the light phase, and this was mainly caused by a large difference occurring between 0600 and 0900 h. In addition to the metabolic chamber studies and circadian rhythm analyses, qPCR of hypothalamic homogenates indicated higher mRNA expression of orexin and transient receptor potential vanilloid 4 cation channels. Consistent with a direct role of IL-15Rα in the hypothalamus, IL-15 treatment of the wild-type mice induced c-Fos expression in the preoptic area. We conclude that activation of hypothalamic neurons by IL-15 in mice contributes to thermoregulation and modifies the metabolic phenotype. |
22843616 | The generation of induced pluripotent stem cells (iPSCs) provides a novel method to facilitate investigations into the mechanisms that control stem cell pluripotency and self-renewal. Myc has previously been shown to be critical for murine embryonic stem cell (mESC) maintenance, while also enhancing directed reprogramming of fibroblasts by effecting widespread changes in gene expression. Despite several studies identifying in vivo target genes, the precise mechanism by which Myc regulates pluripotency remains unknown. Here we report that codeletion of c- and N-MYC in iPSCs and ESCs results in their spontaneous differentiation to primitive endoderm. We show that Myc sustains pluripotency through repression of the primitive endoderm master regulator GATA6, while also contributing to cell cycle control by regulation of the mir-17-92 miRNA cluster. Our findings demonstrate the indispensable requirement for c- or N-myc in pluripotency beyond proliferative and metabolic control. |
22852120 | Type 2 immune responses are defined by the cytokines interleukin-4 (IL-4), IL-5, IL-9 and IL-13, which can either be host protective or have pathogenic activity. Type 2 immunity promotes antihelminth immunity, suppresses type 1-driven autoimmune disease, neutralizes toxins, maintains metabolic homeostasis, and regulates wound repair and tissue regeneration pathways following infection or injury. Nevertheless, when type 2 responses are dysregulated, they can become important drivers of disease. Type 2 immunity induces a complex inflammatory response characterized by eosinophils, mast cells, basophils, type 2 innate lymphoid cells, IL-4-and/or IL-13-conditioned macrophages and T helper 2 (TH2) cells, which are crucial to the pathogenesis of many allergic and fibrotic disorders. As chronic type 2 immune responses promote disease, the mechanisms that regulate their maintenance are thought to function as crucial disease modifiers. This Review discusses the many endogenous negative regulatory mechanisms that antagonize type 2 immunity and highlights how therapies that target some of these pathways are being developed to treat type 2-mediated disease. |
22867765 | We have previously demonstrated that implanted microvessels form a new microcirculation with minimal host-derived vessel investment. Our objective was to define the vascular phenotypes present during neovascularization in these implants and identify post-angiogenesis events. Morphological, functional and transcriptional assessments identified three distinct vascular phenotypes in the implants: sprouting angiogenesis, neovascular remodeling, and network maturation. A sprouting angiogenic phenotype appeared first, characterized by high proliferation and low mural cell coverage. This was followed by a neovascular remodeling phenotype characterized by a perfused, poorly organized neovascular network, reduced proliferation, and re-associated mural cells. The last phenotype included a vascular network organized into a stereotypical tree structure containing vessels with normal perivascular cell associations. In addition, proliferation was low and was restricted to the walls of larger microvessels. The transition from angiogenesis to neovascular remodeling coincided with the appearance of blood flow in the implant neovasculature. Analysis of vascular-specific and global gene expression indicates that the intermediate, neovascular remodeling phenotype is transcriptionally distinct from the other two phenotypes. Therefore, this vascular phenotype likely is not simply a transitional phenotype but a distinct vascular phenotype involving unique cellular and vascular processes. Furthermore, this neovascular remodeling phase may be a normal aspect of the general neovascularization process. Given that this phenotype is arguably dysfunctional, many of the microvasculatures present within compromised or diseased tissues may not represent a failure to progress appropriately through a normally occurring neovascularization phenotype. |
22874817 | How follicular helper T cells (TFH cells) differentiate to regulate B cell immunity is critical for effective protein vaccination. Here we define three transcription factor T-bet–expressing antigen-specific effector helper T cell subsets with distinguishable function, migratory properties and developmental programming in vivo. Expression of the transcriptional repressor Blimp-1 distinguished T zone 'lymphoid' effector helper T cells (CD62LhiCCR7hi) from CXCR5lo 'emigrant' effector helper T cells and CXCR5hi 'resident' TFH cells expressing the transcriptional repressor Bcl-6 (CD62LloCCR7lo). We then show by adoptive transfer and intact polyclonal responses that helper T cells with the highest specific binding of peptide–major histocompatibility complex class II and the most restricted T cell antigen receptor junctional diversity 'preferentially' developed into the antigen-specific effector TFH compartment. Our studies demonstrate a central function for differences in the binding strength of the T cell antigen receptor in the antigen-specific mechanisms that 'program' specialized effector TFH function in vivo. |
22889972 | Inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha) have been implicated in atherogenesis. However, the precise role of TNF-alpha in atherogenesis is still unclear. To examine the effect of TNF-alpha on atherogenesis, we generated compound-deficient mice in apolipoprotein E (apoE) and TNF-alpha (apoE-/-/TNF-alpha-/-) and compared them with apoE-/- mice. Although serum total cholesterol levels were markedly elevated in both apoE-/-/TNF-alpha-/- and apoE-/- mice compared to wild-type mice, no differences were observed between apoE-/-/TNF-alpha-/- and apoE-/- mice. The atherosclerotic plaque area in the aortic luminal surface of apoE-/-/TNF-alpha-/- mice (n=8, 3.1+/-0.4%) was significantly smaller than that of apoE-/- mice (n=7, 4.7+/-0.4%, p<0.001) despite the lack of difference in serum cholesterol levels. The atherosclerotic lesion size in the aortic sinus of apoE-/-/TNF-alpha-/- mice (n=10, 5.1+/-0.3 x 10(5)microm(2)) was also significantly smaller than that of apoE-/- mice (n=11, 7.0+/-0.3 x 10(5)microm(2), p<0.0001). RT-PCR analysis indicated that the expression levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) were significantly higher in apoE-/- than apoE-/-/TNF-alpha-/- mice. Macrophages from apoE(-/-) mice showed higher uptake level of oxidized LDL and increased expression level of scavenger receptor class A (SRA) compared to those from apoE-/-/TNF-alpha-/- mice. These results indicate that TNF-alpha plays an atherogenic role by upregulating the expressions of ICAM-1, VCAM-1 and MCP-1 in the vascular wall, and by inducing SRA expression and oxidized LDL uptake in macrophages. |
22896384 | The airways of the lung develop through a reiterative process of branching morphogenesis that gives rise to the intricate and extensive surface area required for postnatal respiration. The forkhead transcription factors Foxp2 and Foxp1 are expressed in multiple foregut-derived tissues including the lung and intestine. In this report, we show that loss of Foxp2 in mouse leads to defective postnatal lung alveolarization, contributing to postnatal lethality. Using in vitro and in vivo assays, we show that T1alpha, a lung alveolar epithelial type 1 cell-restricted gene crucial for lung development and function, is a direct target of Foxp2 and Foxp1. Remarkably, loss of a single Foxp1 allele in addition to complete loss of Foxp2 results in increased severity of morphological defects in mutant lungs and leads to perinatal loss of all Foxp2(-/-);Foxp1(+/-) mice. Expression of N-myc and Hop, crucial regulators of lung development, is compromised in Foxp2(-/-);Foxp1(+/-) mutants. In addition to the defects in lung development, esophageal muscle development is disrupted in Foxp2(-/-);Foxp1(+/-) embryos, a tissue where Foxp2 and Foxp1 are co-expressed. These data identify Foxp2 and Foxp1 as crucial regulators of lung and esophageal development, underscoring the necessity of these transcription factors in the development of anterior foregut-derived tissues and demonstrating functional cooperativity between members of the Foxp1/2/4 family in tissues where they are co-expressed. |
22896970 | Protein synthesis in all organisms is catalyzed by ribosomes. In comparison to their prokaryotic counterparts, eukaryotic ribosomes are considerably larger and are subject to more complex regulation. The large ribosomal subunit (60S) catalyzes peptide bond formation and contains the nascent polypeptide exit tunnel. We present the structure of the 60S ribosomal subunit from Tetrahymena thermophila in complex with eukaryotic initiation factor 6 (eIF6), cocrystallized with the antibiotic cycloheximide (a eukaryotic-specific inhibitor of protein synthesis), at a resolution of 3.5 angstroms. The structure illustrates the complex functional architecture of the eukaryotic 60S subunit, which comprises an intricate network of interactions between eukaryotic-specific ribosomal protein features and RNA expansion segments. It reveals the roles of eukaryotic ribosomal protein elements in the stabilization of the active site and the extent of eukaryotic-specific differences in other functional regions of the subunit. Furthermore, it elucidates the molecular basis of the interaction with eIF6 and provides a structural framework for further studies of ribosome-associated diseases and the role of the 60S subunit in the initiation of protein synthesis. |
22901758 | The identification of brain tumor stem-like cells (BTSCs) has implicated a role of biological self-renewal mechanisms in clinical brain tumor initiation and propagation. The molecular mechanisms underlying the tumor-forming capacity of BTSCs, however, remain unknown. Here, we have generated molecular signatures of glioblastoma multiforme (GBM) using gene expression profiles of BTSCs and have identified both Sonic Hedgehog (SHH) signaling-dependent and -independent BTSCs and their respective glioblastoma surgical specimens. BTSC proliferation could be abrogated in a pathway-dependent fashion in vitro and in an intracranial tumor model in athymic mice. Both SHH-dependent and -independent brain tumor growth required phosphoinositide 3-kinase-mammalian target of rapamycin signaling. In human GBMs, the levels of SHH and PTCH1 expression were significantly higher in PTEN-expressing tumors than in PTEN-deficient tumors. In addition, we show that hyperactive SHH-GLI signaling in PTEN-coexpressing human GBM is associated with reduced survival time. Thus, distinct proliferation signaling dependence may underpin glioblastoma propagation by BTSCs. Modeling these BTSC proliferation mechanisms may provide a rationale for individualized glioblastoma treatment. |
22914228 | In this present work, we characterized the proteomes of pancreatic ductal adenocarcinoma (PDAC) cell line PANC-1 and normal pancreatic duct cells by mass spectrometry using LTQ-Orbitrap and identified more than 1700 proteins from each sample. On the basis of the spectra count label-free quantification approach, we identified a large number of differentially expressed metabolic enzymes and proteins involved in cytoskeleton, cell adhesion, transport, transcription, translation, and cell proliferation as well. The data demonstrated that metabolic pathways were altered in PANC-1, consistent with the Warburg effect. In addition, the comparative MS analysis unveiled anomalous metabolism of glutamine, suggesting that glutamine was largely consumed as a nitrogen donor in nucleotide and amino acid biosynthesis in PANC-1. Our analysis provides a potentially comprehensive picture of metabolism in PANC-1, which may serve as the basis of new diagnostics and treatment of PDAC. |
22922353 | CONTEXT Overweight and obesity are increasing in the United States. Changes in diet and physical activity are important for weight control. OBJECTIVES To examine the prevalence of attempting to lose or to maintain weight and to describe weight control strategies among US adults. DESIGN The Behavioral Risk Factor Surveillance System, a random-digit telephone survey conducted in 1996 by state health departments. Setting The 49 states (and the District of Columbia) that participated in the survey. PARTICIPANTS Adults aged 18 years and older (N = 107 804). MAIN OUTCOME MEASURES Reported current weights and goal weights, prevalence of weight loss or maintenance attempts, and strategies used to control weight (eating fewer calories, eating less fat, or using physical activity) by population subgroup. RESULTS The prevalence of attempting to lose and maintain weight was 28.8% and 35.1 % among men and 43.6% and 34.4% among women, respectively. Among those attempting to lose weight, a common strategy was to consume less fat but not fewer calories (34.9% of men and 40.0% of women); only 21.5% of men and 19.4% of women reported using the recommended combination of eating fewer calories and engaging in at least 150 minutes of leisure-time physical activity per week. Among men trying to lose weight, the median weight was 90.4 kg with a goal weight of 81.4 kg. Among women, the median weight was 70.3 kg with a goal weight of 59.0 kg. CONCLUSIONS Weight loss and weight maintenance are common concerns for US men and women. Most persons trying to lose weight are not using the recommended combination of reducing calorie intake and engaging in leisure-time physical activity 150 minutes or more per week. |
22942787 | CONTEXT Medicare's reimbursement policy was changed in 1998 to provide coverage for screening colonoscopies for patients with increased colon cancer risk, and expanded further in 2001 to cover screening colonoscopies for all individuals. OBJECTIVE To determine whether the Medicare reimbursement policy changes were associated with an increase in either colonoscopy use or early stage colon cancer diagnosis. DESIGN, SETTING, AND PARTICIPANTS Patients in the Surveillance, Epidemiology, and End Results Medicare linked database who were 67 years of age and older and had a primary diagnosis of colon cancer during 1992-2002, as well as a group of Medicare beneficiaries who resided in Surveillance, Epidemiology, and End Results areas but who were not diagnosed with cancer. MAIN OUTCOME MEASURES Trends in colonoscopy and sigmoidoscopy use among Medicare beneficiaries without cancer were assessed using multivariate Poisson regression. Among the patients with cancer, stage was classified as early (stage I) vs all other (stages II-IV). Time was categorized as period 1 (no screening coverage, 1992-1997), period 2 (limited coverage, January 1998-June 2001), and period 3 (universal coverage, July 2001-December 2002). A multivariate logistic regression (outcome = early stage) was used to assess temporal trends in stage at diagnosis; an interaction term between tumor site and time was included. RESULTS Colonoscopy use increased from an average rate of 285/100,000 per quarter in period 1 to 889 and 1919/100,000 per quarter in periods 2 (P<.001) and 3 (P vs 2<.001), respectively. During the study period, 44,924 eligible patients were diagnosed with colorectal cancer. The proportion of patients diagnosed at an early stage increased from 22.5% in period 1 to 25.5% in period 2 and 26.3% in period 3 (P<.001 for each pairwise comparison). The changes in Medicare coverage were strongly associated with early stage at diagnosis for patients with proximal colon lesions (adjusted relative risk period 2 vs 1, 1.19; 95% confidence interval, 1.13-1.26; adjusted relative risk period 3 vs 2, 1.10; 95% confidence interval, 1.02-1.17) but weakly associated, if at all, for patients with distal colon lesions (adjusted relative risk period 2 vs 1, 1.07; 95% confidence interval, 1.01-1.13; adjusted relative risk period 3 vs 2, 0.97; 95% confidence interval, 0.90-1.05). CONCLUSIONS Expansion of Medicare reimbursement to cover colon cancer screening was associated with an increased use of colonoscopy for Medicare beneficiaries, and for those who were diagnosed with colon cancer, an increased probability of being diagnosed at an early stage. The selective effect of the coverage change on proximal colon lesions suggests that increased use of whole-colon screening modalities such as colonoscopy may have played a pivotal role. |
22968257 | Histone/protein deacetylases (HDACs) decrease histone and protein acetylation, typically leading to suppression of gene transcription and modulation of various protein functions. We found significant differences in expression of HDAC before and after stimulation of human T regulatory (Treg) and T effector cells, suggesting the potential for future selective targeting of Tregs with HDAC inhibitors (HDACi). Use of various HDACi small molecules enhanced, by up to 4.5-fold (average 2-fold), the suppressive functions of both freshly isolated and expanded human Tregs, consistent with our previous murine data. HDACi use increased Treg expression of CTLA-4, a key negative regulator of immune response, and we found a direct and significant correlation between CTLA-4 expression and Treg suppression. Hence, HDACi compounds are promising pharmacologic tools to increase Treg suppressive functions, and this action may potentially be of use in patients with autoimmunity or post-transplantation. |
22972632 | Inhibition of αvβ3 or αvβ5 integrin function has been reported to suppress neovascularization and tumor growth, suggesting that these integrins are critical modulators of angiogenesis. Here we report that mice lacking β3 integrins or both β3 and β5 integrins not only support tumorigenesis, but have enhanced tumor growth as well. Moreover, the tumors in these integrin-deficient mice display enhanced angiogenesis, strongly suggesting that neither β3 nor β5 integrins are essential for neovascularization. We also observed that angiogenic responses to hypoxia and vascular endothelial growth factor (VEGF) are augmented significantly in the absence of β3 integrins. We found no evidence that the expression or functions of other integrins were altered as a consequence of the β3 deficiency, but we did observe elevated levels of VEGF receptor-2 (also called Flk-1) in β3-null endothelial cells. These data indicate that αvβ3 and αvβ5 integrins are not essential for vascular development or pathological angiogenesis and highlight the need for further evaluation of the mechanisms of action of αv-integrin antagonists in anti-angiogenic therapeutics. |
22973574 | Macrophages and dendritic cells (DCs) are key components of cellular immunity and are thought to originate and renew from hematopoietic stem cells (HSCs). However, some macrophages develop in the embryo before the appearance of definitive HSCs. We thus reinvestigated macrophage development. We found that the transcription factor Myb was required for development of HSCs and all CD11b(high) monocytes and macrophages, but was dispensable for yolk sac (YS) macrophages and for the development of YS-derived F4/80(bright) macrophages in several tissues, such as liver Kupffer cells, epidermal Langerhans cells, and microglia--cell populations that all can persist in adult mice independently of HSCs. These results define a lineage of tissue macrophages that derive from the YS and are genetically distinct from HSC progeny. |
22975806 | For individuals genetically predisposed to breast and ovarian cancer through inheritance of a mutant BRCA allele, somatic loss of heterozygosity affecting the wild-type allele is considered obligatory for cancer initiation and/or progression. However, several lines of evidence suggest that phenotypic effects may result from BRCA haploinsufficiency. Archival fixed and embedded tissue specimens from women with germ line deleterious mutations in BRCA1 or BRCA2 were identified. After pathologic review, focal areas of normal breast epithelium, atypical ductal hyperplasia, ductal carcinoma-in-situ, and invasive ductal carcinoma were identified from 14 BRCA1-linked and 9 BRCA2-linked breast cancers. Ten BRCA-linked prophylactic mastectomy specimens and 12 BRCA-linked invasive ovarian carcinomas were also studied. Laser catapult microdissection was used to isolate cells from the various pathologic lesions and corresponding normal tissues. After DNA isolation, real-time polymerase chain reaction assays were used to quantitate the proportion of wild-type to mutant BRCA alleles in each tissue sample. Quantitative allelotyping of microdissected cells revealed a high level of heterogeneity in loss of heterozygosity within and between preinvasive lesions and invasive cancers from BRCA1 and BRCA2 heterozygotes with breast cancer. In contrast, all BRCA-associated ovarian cancers displayed complete loss of the wild-type BRCA allele. These data suggest that loss of the wild-type BRCA allele is not required for BRCA-linked breast tumorigenesis, which would have important implications for the genetic mechanism of BRCA tumor suppression and for the clinical management of this patient population. |
22980205 | PURPOSE OF REVIEW Greater understanding of the biology and genetics of urothelial carcinoma is helping to identify and define the role of molecules and pathways appropriate for novel-targeted therapies. Here, we review the targeted therapies that have been reported or are in ongoing urothelial carcinoma clinical trials, and highlight molecular targets characterized in preclinical and clinical studies. RECENT FINDINGS Trials in nonmuscle-invasive bladder cancer are evaluating the role of immunotherapy and agents targeting vascular endothelial growth factor (VEGF) or fibroblast growth factor receptor-3. In muscle-invasive bladder cancer, neoadjuvant studies have focused on combining VEGF agents with chemotherapy; adjuvant studies are testing vaccines and agents targeting the human epidermal growth factor receptor 2, p53, and Hsp27. In the first-line treatment of metastatic urothelial carcinoma, tubulin, cytotoxic T-lymphocyte antigen 4, Hsp27, and p53 are novel targets in clinical trials. The majority of targeted agents studied in urothelial carcinoma are in the second-line setting; new targets include CD105, polo-like kinase-1, phosphatidylinositide 3-kinases (PI3K), transforming growth factor β receptor/activin receptor-like kinase β, estrogen receptor, and the hepatocyte growth factor receptor (HGFR or MET). SUMMARY Development of targeted therapies for urothelial carcinoma is still in early stages, consequently there have been no major therapeutic advances to date. However, greater understanding of urothelial carcinoma and solid tumor biology has resulted in a proliferation of clinical trials that could lead to significant advances in treatment strategies. |
22995579 | The tricyclic antidepressant, amitriptyline, is an effective drug for the treatment of chronic tension-type headache and for other chronic pain syndromes, but it is also effective in the prophylaxis of an episodic type of headache such as migraine. However, its efficacy in episodic tension-type headache has not yet been clarified. We compared the efficacy of amitriptyline (25 mg/day) in 82 nondepressed patients with either chronic or episodic tension-type headache in an open-label study. Amitriptyline significantly reduced (P < 0.05) frequency and duration of headache as well as analgesic consumption in chronic, but not in episodic, tension-type headache. Further placebo-controlled trials, possibly with higher doses of amitriptyline, might confirm if the different pattern of response to amitriptyline can be explained in terms of different involvement of central nociception and of peripheral myofascial factors in the chronic and in the episodic forms of tension-type headache. |
22997657 | The transcription factor Kruppel-like factor 2 (KLF2) was proposed to regulate genes involved in cell cycle entry and T cell trafficking; however, the physiological role of its expression in postactivated T cells is not well defined. Previous studies suggested that the cytokines IL-2 and IL-15 differentially regulate KLF2 re-expression in postactivation T cells and that these cytokines also influence effector versus memory T cell differentiation. Using conditional and inducible KLF2-knockout model systems, we tested the specific role of KLF2 expression in activated CD8(+) T cells cultured with these cytokines. KLF2 was required for effective transcription of sphingosine-1-phosphate receptor-1 (S1P(1)) and CD62L in postactivation T cells. However, although different cytokines dramatically altered the expression of cell-cycle-related genes, endogenous KLF2 had a minimal impact. Correspondingly, KLF2-deficient T cells showed dysregulated trafficking but not altered proliferative characteristics following in vivo responses to Ag. Thus, our data help to define KLF2-dependent and -independent aspects of activated CD8(+) T cell differentiation and argue against a physiological role in cell cycle regulation. |
23052989 | Adult neurogenesis persists in the subventricular zone and the dentate gyrus and can be induced upon central nervous system injury. However, the final contribution of newborn neurons to neuronal networks is limited. Here we show that in neural stem cells, stimulation of the "death receptor" CD95 does not trigger apoptosis but unexpectedly leads to increased stem cell survival and neuronal specification. These effects are mediated via activation of the Src/PI3K/AKT/mTOR signaling pathway, ultimately leading to a global increase in protein translation. Induction of neurogenesis by CD95 was further confirmed in the ischemic CA1 region, in the naive dentate gyrus, and after forced expression of CD95L in the adult subventricular zone. Lack of hippocampal CD95 resulted in a reduction in neurogenesis and working memory deficits. Following global ischemia, CD95-mediated brain repair rescued behavioral impairment. Thus, we identify the CD95/CD95L system as an instructive signal for ongoing and injury-induced neurogenesis. |
23076291 | We recently identified a novel mechanism for modulation of the phosphorylation state and function of the N-methyl-d-aspartate (NMDA) receptor via the scaffolding protein RACK1. We found that RACK1 binds both the NR2B subunit of the NMDA receptor and the nonreceptor protein-tyrosine kinase, Fyn. RACK1 inhibits Fyn phosphorylation of NR2B and decreases NMDA receptor-mediated currents in CA1 hippocampal slices (Yaka, R., Thornton, C., Vagts, A. J., Phamluong, K., Bonci, A., and Ron, D. (2002) Proc. Natl. Acad. Sci. U. S. A. 99, 5710-5715). Here, we identified the signaling cascade by which RACK1 is released from the NMDA receptor complex and identified the consequences of the dissociation. We found that activation of the cAMP/protein kinase A pathway in hippocampal slices induced the release of RACK1 from NR2B and Fyn. This resulted in the induction of NR2B phosphorylation and the enhancement of NMDA receptor-mediated activity via Fyn. We identified the neuropeptide, pituitary adenylate cyclase activating polypeptide (PACAP(1-38)), as a ligand that induced phosphorylation of NR2B and enhanced NMDA receptor potentials. Finally, we found that activation of the cAMP/protein kinase A pathway induced the movement of RACK1 to the nuclear compartment in dissociated hippocampal neurons. Nuclear RACK1 in turn was found to regulate the expression of brain-derived neurotrophic factor induced by PACAP(1-38). Taken together our results suggest that activation of adenylate cyclase by PACAP(1-38) results in the release of RACK1 from the NMDA receptor and Fyn. This in turn leads to NMDA receptor phosphorylation, enhanced activity mediated by Fyn, and to the induction of brain-derived neurotrophic factor expression by RACK1. |
23117378 | The definition of sudden infant death syndrome (SIDS) originally appeared in 1969 and was modified 2 decades later. During the following 15 years, an enormous amount of additional information has emerged, justifying additional refinement of the definition of SIDS to incorporate epidemiologic features, risk factors, pathologic features, and ancillary test findings. An expert panel of pediatric and forensic pathologists and pediatricians considered these issues and developed a new general definition of SIDS for administrative and vital statistics purposes. The new definition was then stratified to facilitate research into sudden infant death. Another category, defined as unclassified sudden infant deaths, was introduced for cases that do not meet the criteria for a diagnosis of SIDS and for which alternative diagnoses of natural or unnatural conditions were equivocal. It is anticipated that these new definitions will be modified in the future to accommodate new understanding of SIDS and sudden infant death. |
23124332 | We investigated extraneural manifestations in scrapie-infected transgenic mice expressing prion protein lacking the glycophosphatydylinositol membrane anchor. In the brain, blood, and heart, both abnormal protease-resistant prion protein (PrPres) and prion infectivity were readily detected by immunoblot and by inoculation into nontransgenic recipients. The titer of infectious scrapie in blood plasma exceeded 10(7) 50% infectious doses per milliliter. The hearts of these transgenic mice contained PrPres-positive amyloid deposits that led to myocardial stiffness and cardiac disease. |
23126677 | BACKGROUND MicroRNAs (miRNAs) are small non-coding RNA molecules. Reduced or increased levels of specific miRNAs are observed in colon and other cancers, supporting their role in carcinogenesis. Detection of colorectal polyps is the cornerstone of the Bowel Cancer Screening Programme in the UK. However, uptake of screening nationally remains under 60%. We aimed to see whether circulating plasma miRNAs can be used to screen for patients with colorectal polyps, adenomas, or both. METHODS Blood samples were taken from patients from the Bowel Cancer Screening Programme (asymptomatic but faecal occult blood testing [FOBt] positive). Plasma RNA was extracted, target miRNAs (19a, 98, 146b, 186, 191, 222*, 331-5p, 452, 625, 664, 1247) were identified on pooled case miRNA assay cards, and miRNA fraction was quantified by quantitative RT-PCR assay. Results were compared with endoscopy reports and with histology of any polyps identified and removed. Analysis was done with Excel (2011) and SPSS (version 20) software. FINDINGS 210 patients were included (117 with polyps, 12 with cancer, 81 healthy controls [FOBt positive]). The miRNA panel showed significant differences in expression (on t testing) for patients compared with controls for those with polyps, cancer, or both (miR-19a, p=0·0184; miR-98, p=0·0206; miR-146b, p=0·0029; miR-186, p=0·0006; miR-62,5 p=0·0008), polyps (miR-19a, p=0·0233; miR-98, p=0·0224; miR-146b, p=0·003; miR-186, p=0·0004; miR-625, p=0·001), adenomas (miR-19a, p=0·0339; miR-98, p=0·0266; miR-146b, p=0·0045; miR-186, p=0·0008; miR-625, p=0·0049), multiple adenomas (both sides of colon; miR-146b, p=0·0194; miR-186, p=0·0226; miR-625, p=0·0013), and right-sided adenomas (miR-98, p=0·031; miR-146b, p=0·0076; miR-186, p=0·0041; miR-331-5p, p=0·0142; miR-625, p=0·0049). Receiver operating characteristic analysis showed sensitivity of 60% or more, and specificity of 86% or more for men with polyps, men with adenomas, all patients with haemorrhoids or diverticulosis and polyps, and all patients with haemorrhoids or diverticulosis and adenomas. INTERPRETATION The target miRNAs that we identified showed significant differences in expression levels for patients with polyps and patients with adenomas from controls. Use of this panel has potential as a screening test. FUNDING Bowel Disease Research Foundation. |
23136735 | OBJECTIVE To evaluate the cumulative incidence of cervical intraepithelial neoplasia II or worse (grade II+) or cervical intraepithelial neoplasia grade III+ after short term persistence of prevalently detected carcinogenic human papillomavirus (HPV). DESIGN Population based cohort study. SETTING Guanacaste, Costa Rica. PARTICIPANTS 2282 sexually active women actively followed after enrolment. MAIN OUTCOME MEASURES Primary end points: three year and five year cumulative incidence of histologically confirmed cervical intraepithelial neoplasia grade II+ (n=70). Cervical specimens collected at each visit tested for more than 40 HPV genotypes. HPV 16, 18, 26, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68, 73, and 82 were considered the primary carcinogenic genotypes. RESULTS Women who tested positive for a carcinogenic HPV at enrolment and after about one year (9-21 months) (positive/positive) had a three year cumulative incidence of cervical intraepithelial neoplasia grade II+ of 17.0% (95% confidence interval 12.1% to 22.0%). Those who tested negative/positive (3.4%, 0.1% to 6.8%), positive/negative (1.2%, -0.2% to 2.5%), and negative/negative (0.5%, 0.1% to 0.9%) were at a significantly lower risk. There was little difference in the cumulative incidence of cervical intraepithelial neoplasia grade II+ between testing positive twice for any carcinogenic HPV genotype (same genotype or different genotypes) v testing positive twice for the same carcinogenic genotype (17.0% v 21.3%, respectively). Short term persistence of HPV 16 strongly predicted cervical intraepithelial neoplasia grade II+, with a three year cumulative incidence of 40.8% (26.4% to 55.1%). Similar patterns were observed for the five year cumulative incidence of grade II+ and for three year and five year cumulative incidence of grade III+. CONCLUSIONS Short term persistence of a prevalently detected carcinogenic HPV infection, especially HPV 16, strongly predicts a subsequent diagnosis of cervical intraepithelial neoplasia II+ over the next few years. |
23141360 | The morphogenesis of developing embryos and organs relies on the ability of cells to remodel their contacts with neighbouring cells. Using quantitative modelling and laser nano-dissection, we probed the mechanics of a morphogenetic process, the elongation of Drosophila melanogaster embryos, which results from polarized cell neighbour exchanges. We show that anisotropy of cortical tension at apical cell junctions is sufficient to drive tissue elongation. We estimated its value through comparisons between in silico and in vivo data using various tissue descriptors. Nano-dissection of the actomyosin network indicates that tension is anisotropically distributed and depends on myosin II accumulation. Junction relaxation after nano-dissection also suggests that cortical elastic forces are dominant in this process. Interestingly, fluctuations in vertex position (points where three or more cells meet) facilitate neighbour exchanges. We delineate the contribution of subcellular tensile activity polarizing junction remodelling, and the permissive role of vertex fluctuations during tissue elongation. |
23148978 | The action of different metabolic inhibitors on phagocytosis by macrophages from mouse peritoneal exudate cultured in vitro was studied. The following metabolic inhibitors were tested: sodium iodoacetate, sodium fluoride, sodium fluoroacetate, sodium malonate, 2-4-dinitrophenol, sodium azide, ouabain and cycloheximide, all at the concentration of 10(-3) M. Iodoacetate caused a strong inhibitory effect on phagocytosis; this observation confirms that glycolysis is the main source of energy for the phagocytic process. On the contrary, fluoride, although it is an effective inhibitor of glycolysis, did not exert any effect. This difference may be explained by the fact that sodium fluoride blocks anaerobic glycolysis only in vitro at an unphysiological temperature (0 degrees C). Fluoroacetate and malonate, two compounds which interfere with the Krebs cycle, did not inhibit phagocytosis, but it is known that the Krebs cycle activity is poorly developed in the macrophagic cells. Sodium azide and 2-4-dinitrophenol, two inhibitors of oxidative phosphorylation, showed an effect on phagocytosis only after 3 h of contact with the cell cultures. Ouabain blocks Na+ and K+ transport across the plasma membrane and, probably, it inhibited phagocytosis by interfering with the movements of the cell membrane. Finally, the mode of action of cycloheximide on phagocytosis is uncertain. This compound inhibits the protein synthesis and, perhaps, it can act by preventing the renewal of the cell membrane. |
23160444 | Neuronal growth cones move forward by dynamically connecting actin-based motility to substrate adhesion, but the mechanisms at the individual molecular level remain unclear. We cultured primary neurons on N-cadherin-coated micropatterned substrates, and imaged adhesion and cytoskeletal proteins at the ventral surface of growth cones using single particle tracking combined to photoactivated localization microscopy (sptPALM). We demonstrate transient interactions in the second time scale between flowing actin filaments and immobilized N-cadherin/catenin complexes, translating into a local reduction of the actin retrograde flow. Normal actin flow on micropatterns was rescued by expression of a dominant negative N-cadherin construct competing for the coupling between actin and endogenous N-cadherin. Fluorescence recovery after photobleaching (FRAP) experiments confirmed the differential kinetics of actin and N-cadherin, and further revealed a 20% actin population confined at N-cadherin micropatterns, contributing to local actin accumulation. Computer simulations with relevant kinetic parameters modeled N-cadherin and actin turnover well, validating this mechanism. Such a combination of short- and long-lived interactions between the motile actin network and spatially restricted adhesive complexes represents a two-tiered clutch mechanism likely to sustain dynamic environment sensing and provide the force necessary for growth cone migration. |
23180075 | The cholesterol side-chain cleavage enzyme, cytochrome P450scc, initiates the biosynthesis of all steroid hormones. Adrenal and gonadal strategies for P450scc gene transcription are essentially identical and depend on the orphan nuclear receptor steroidogenic factor-1, but the placental strategy for transcription of P450scc employs cis-acting elements different from those used in the adrenal strategy and is independent of steroidogenic factor-1. Because placental expression of P450scc is required for human pregnancy, we sought factors that bind to the -155/-131 region of the human P450scc promoter, which participates in its placental but not adrenal or gonadal transcription. A yeast one-hybrid screen of 2.4 x 10(6) cDNA clones from human placental JEG-3 cells yielded two unique clones; one is the previously described transcription factor LBP-1b, which is induced by HIV, type I infection of lymphocytes, and the other is a new factor, termed LBP-9, that shares 83% amino acid sequence identity with LBP-1b. When expressed in transfected yeast, both factors bound specifically to the -155/-131 DNA; antisera to LBP proteins supershifted the LBP-9.DNA complex and inhibited formation of the LBP-1b. DNA complex. Reverse transcriptase-polymerase chain reaction detected LBP-1b in human placental JEG-3, adrenal NCI-H295A, liver HepG2, cervical HeLa, and monkey kidney COS-1 cells, but LBP-9 was detected only in JEG-3 cells. When the -155/-131 fragment was linked to a minimal promoter, co-expression of LBP-1b increased transcription 21-fold in a dose-dependent fashion, but addition of LBP-9 suppressed the stimulatory effect of LBP-1b. The roles of LBP transcription factors in normal human physiology have been unclear. Their modulation of placental but not adrenal P450scc transcription underscores the distinctiveness of placental strategies for steroidogenic enzyme gene transcription. |
23190392 | Polyploidization is a natural process that frequently accompanies differentiation; its deregulation is linked to genomic instability and cancer. Despite its relevance, why cells select different polyploidization mechanisms is unknown. Here we report a systematic genetic analysis of endomitosis, a process in which megakaryocytes become polyploid by entering mitosis but aborting anaphase. Whereas ablation of the APC/C cofactor Cdc20 results in mitotic arrest and severe thrombocytopenia, lack of the kinases Aurora-B, Cdk1, or Cdk2 does not affect megakaryocyte polyploidization or platelet levels. Ablation of Cdk1 forces a switch to endocycles without mitosis, whereas polyploidization in the absence of Cdk1 and Cdk2 occurs in the presence of aberrant re-replication events. Importantly, ablation of these kinases rescues the defects in Cdc20 null megakaryocytes. These findings suggest that endomitosis can be functionally replaced by alternative polyploidization mechanisms in vivo and provide the cellular basis for therapeutic approaches aimed to discriminate mitotic and polyploid cells. |
23208167 | Pioneer transcription factors (TFs) function as genomic first responders, binding to inaccessible regions of chromatin to promote enhancer formation. The mechanism by which pioneer TFs gain access to chromatin remains an important unanswered question. Here we show that PARP-1, a nucleosome-binding protein, cooperates with intrinsic properties of the pioneer TF Sox2 to facilitate its binding to intractable genomic loci in embryonic stem cells. These actions of PARP-1 occur independently of its poly(ADP-ribosyl) transferase activity. PARP-1-dependent Sox2-binding sites reside in euchromatic regions of the genome with relatively high nucleosome occupancy and low co-occupancy by other transcription factors. PARP-1 stabilizes Sox2 binding to nucleosomes at suboptimal sites through cooperative interactions on DNA. Our results define intrinsic and extrinsic features that determine Sox2 pioneer activity. The conditional pioneer activity observed with Sox2 at a subset of binding sites may be a key feature of other pioneer TFs operating at intractable genomic loci. |
23237995 | Hormones play a critical role in driving major stage transitions and developmental timing events in many species. In the nematode C. elegans the steroid hormone receptor, DAF-12, works at the confluence of pathways regulating developmental timing, stage specification, and longevity. DAF-12 couples environmental and physiologic signals to life history regulation, and it is embedded in a rich architecture governing diverse processes. Here, we highlight the molecular insights, extraordinary circuitry, and signaling pathways governing life stage transitions in the worm and how they have yielded fundamental insights into steroid regulation of biological time. |
23260700 | Angiopoietin 2 (Ang2) was originally shown to be a competitive antagonist for Ang1 of the receptor tyrosine kinase Tie2 in endothelial cells (ECs). Since then, reports have conflicted on whether Ang2 is an agonist or antagonist of Tie2. Here we show that Ang2 functions as an agonist when Ang1 is absent but as a dose-dependent antagonist when Ang1 is present. Exogenous Ang2 activates Tie2 and the promigratory, prosurvival PI3K/Akt pathway in ECs but with less potency and lower affinity than exogenous Ang1. ECs produce Ang2 but not Ang1. This endogenous Ang2 maintains Tie2, phosphatidylinositol 3-kinase, and Akt activities, and it promotes EC survival, migration, and tube formation. However, when ECs are stimulated with Ang1 and Ang2, Ang2 dose-dependently inhibits Ang1-induced Tie2 phosphorylation, Akt activation, and EC survival. We conclude that Ang2 is both an agonist and an antagonist of Tie2. Although Ang2 is a weaker agonist than Ang1, endogenous Ang2 maintains a level of Tie2 activation that is critical to a spectrum of EC functions. These findings may reconcile disparate reports of Ang2's effect on Tie2, impact our understanding of endogenous receptor tyrosine kinase signal transduction mechanisms, and affect how Ang2 and Tie2 are targeted under conditions such as sepsis and cancer. |
23267371 | Vitamin D insufficiency affects almost 50% of the population worldwide. An estimated 1 billion people worldwide, across all ethnicities and age groups, have a vitamin D deficiency (VDD). This pandemic of hypovitaminosis D can mainly be attributed to lifestyle (for example, reduced outdoor activities) and environmental (for example, air pollution) factors that reduce exposure to sunlight, which is required for ultraviolet-B (UVB)-induced vitamin D production in the skin. High prevalence of vitamin D insufficiency is a particularly important public health issue because hypovitaminosis D is an independent risk factor for total mortality in the general population. Current studies suggest that we may need more vitamin D than presently recommended to prevent chronic disease. As the number of people with VDD continues to increase, the importance of this hormone in overall health and the prevention of chronic diseases are at the forefront of research. VDD is very common in all age groups. As few foods contain vitamin D, guidelines recommended supplementation at suggested daily intake and tolerable upper limit levels. It is also suggested to measure the serum 25-hydroxyvitamin D level as the initial diagnostic test in patients at risk for deficiency. Treatment with either vitamin D2 or vitamin D3 is recommended for deficient patients. A meta-analysis published in 2007 showed that vitamin D supplementation was associated with significantly reduced mortality. In this review, we will summarize the mechanisms that are presumed to underlie the relationship between vitamin D and understand its biology and clinical implications. |
23273454 | Eleven mammalian toll-like receptors (TLRs 1-11) have been identified to date and are known to play a crucial role in the regulation of immune responses; however, the factors that regulate TLR expression and function in vivo are poorly understood. Therefore, in the present study, we investigated the physiological regulation of TLR expression and function in humans. To examine the influence of diurnal rhythmicity on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers (n = 8) at time points coinciding with the peak and nadir in the endogenous circulating cortisol concentration. While no diurnal rhythmicity in the expression of TLRs 1, 2, 4 or 9 was observed, the upregulation of costimulatory (CD80 and CD86) and antigen-presenting (MHC class II) molecules on CD14(+) monocytes following activation with specific TLR ligands was greater (P < 0.05) in samples obtained in the evening compared with the morning. To examine the influence of physical stress on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers (n = 11) at rest and following 1.5 h of strenuous exercise in the heat (34 degrees C). Strenuous exercise resulted in a decrease (P < 0.005) in the expression of TLRs 1, 2 and 4 on CD14(+) monocytes. Furthermore, the upregulation of CD80, CD86, MHC class II and interleukin-6 by CD14(+) monocytes following activation with specific TLR ligands was decreased (P < 0.05) in samples obtained following exercise compared with at rest. These results demonstrate that TLR function is subject to modulation under physiological conditions in vivo and provide evidence for the role of immunomodulatory hormones in the regulation of TLR function. |
23286603 | Liver X receptors (LXR) are oxysterol-activated nuclear receptors that play a central role in reverse cholesterol transport through up-regulation of ATP-binding cassette transporters (ABCA1 and ABCG1) that mediate cellular cholesterol efflux. Mouse models of atherosclerosis exhibit reduced atherosclerosis and enhanced regression of established plaques upon LXR activation. However, the coregulatory factors that affect LXR-dependent gene activation in macrophages remain to be elucidated. To identify novel regulators of LXR that modulate its activity, we used affinity purification and mass spectrometry to analyze nuclear LXRα complexes and identified poly(ADP-ribose) polymerase-1 (PARP-1) as an LXR-associated factor. In fact, PARP-1 interacted with both LXRα and LXRβ. Both depletion of PARP-1 and inhibition of PARP-1 activity augmented LXR ligand-induced ABCA1 expression in the RAW 264.7 macrophage line and primary bone marrow-derived macrophages but did not affect LXR-dependent expression of other target genes, ABCG1 and SREBP-1c. Chromatin immunoprecipitation experiments confirmed PARP-1 recruitment at the LXR response element in the promoter of the ABCA1 gene. Further, we demonstrated that LXR is poly(ADP-ribosyl)ated by PARP-1, a potential mechanism by which PARP-1 influences LXR function. Importantly, the PARP inhibitor 3-aminobenzamide enhanced macrophage ABCA1-mediated cholesterol efflux to the lipid-poor apolipoprotein AI. These findings shed light on the important role of PARP-1 on LXR-regulated lipid homeostasis. Understanding the interplay between PARP-1 and LXR may provide insights into developing novel therapeutics for treating atherosclerosis. |
23294314 | OBJECTIVE To assess whether advance provision of emergency contraception increases its use and whether it has secondary effects on regular contraceptive use. METHODS We conducted a controlled trial of female clients, aged 16-24 years, who attended a publicly funded family planning clinic. Women were systematically assigned to receive an advance provision of emergency contraception and education (treatment) or education only (control). Among 263 participants enrolled (133 treatment, 130 control), follow-up was completed in 213 (111 treatment, 102 control). The main outcome measures were emergency contraception knowledge and use, frequency of unprotected sex, and pattern of contraceptive use in the past 4 months. RESULTS Participants were aware of emergency contraception at follow-up, but the treatment group was three times as likely to use it (P =.006). Although the treatment group did not report higher frequencies of unprotected sex than the control group, women in the treatment group (28%) were more likely than those in the control group (17%) to report using less effective contraception at follow-up compared with enrollment (P =.05). The proportion of women in both groups who reported consistent pill use increased from enrollment to follow-up (34% versus 45%); however, the control group (58%) was more likely than the treatment group (32%) to report consistent pill use at follow-up (P =.03). CONCLUSION Use of emergency contraception was increased by providing it in advance, but not by education alone. Changes to less effective contraceptive methods and patterns of pill use were potentially negative effects that need to be explored in relation to observed benefits. |
23305884 | Epstein-Barr virus (EBV) is an oncogenic human herpesvirus that dramatically reorganizes host gene expression to immortalize primary B cells. In this study, we analyzed EBV-regulated host gene expression changes following primary B-cell infection, both during initial proliferation and through transformation into lymphoblastoid cell lines (LCLs). While most EBV-regulated mRNAs were changed during the transition from resting, uninfected B cells through initial B-cell proliferation, a substantial number of mRNAs changed uniquely from early proliferation through LCL outgrowth. We identified constitutively and dynamically EBV-regulated biological processes, protein classes, and targets of specific transcription factors. Early after infection, genes associated with proliferation, stress responses, and the p53 pathway were highly enriched. However, the transition from early to long-term outgrowth was characterized by genes involved in the inhibition of apoptosis, the actin cytoskeleton, and NF-κB activity. It was previously thought that the major viral protein responsible for NF-κB activation, latent membrane protein 1 (LMP1), is expressed within 2 days after infection. Our data indicate that while this is true, LCL-level LMP1 expression and NF-κB activity are not evident until 3 weeks after primary B-cell infection. Furthermore, heterologous NF-κB activation during the first week after infection increased the transformation efficiency, while early NF-κB inhibition had no effect on transformation. Rather, inhibition of NF-κB was not toxic to EBV-infected cells until LMP1 levels and NF-κB activity were high. These data collectively highlight the dynamic nature of EBV-regulated host gene expression and support the notion that early EBV-infected proliferating B cells have a fundamentally distinct growth and survival phenotype from that of LCLs. |
23351136 | The tastes of sugars (sweet) and glutamate (umami) are thought to be detected by T1r receptors expressed in taste cells. Molecular genetics and heterologous expression implicate T1r2 plus T1r3 as a sweet-responsive receptor,and T1r1 plus T1r3,as well as a truncated form of the type 4 metabotropic glutamate receptor (taste-mGluR4),as umami-responsive receptors. Here,we show that mice lacking T1r3 showed no preference for artificial sweeteners and had diminished but not abolished behavioral and nerve responses to sugars and umami compounds. These results indicate that T1r3-independent sweet- and umami-responsive receptors and/or pathways exist in taste cells. |
23388442 | Research describing fatty acids as modulators of inflammation and immune responses abounds. Many of these studies have focused on one particular group of fatty acids, omega-3. The data from animal studies have shown that these fatty acids can have powerful anti-inflammatory and immunomodulatory activities in a wide array of diseases (e.g., autoimmunity, arthritis, and infection). However, the evidence from human trials is more equivocal. In this review, a historical framework for understanding how and why fatty acids may affect the immune system is provided. Second, highlights of two recent landmark reports from the Agency for Healthcare Research and Quality are presented. These reports critically evaluate the evidence from human clinical trials of omega-3 fatty acids and rheumatoid arthritis, asthma, and a few other immune-mediated diseases. Third, the data from human clinical trials investigating the impact of various bioactive fatty acids on ex vivo and in vivo immune response are reviewed. Limitations in experimental design and immune assays commonly used are discussed. The discordance between expectation and evidence in this field has been a disappointment. Recommendations for improving both animal-based and human studies are provided. |
23389795 | Here, we give a historical overview of the search for genetic variants that influence the susceptibility of an individual to a chronic disease, from RA Fisher's seminal work to the current excitement of whole-genome association studies (WGAS). We then discuss the concepts behind the identification of common variants as disease causal factors and contrast them to the basic ideas that underlie the rare variant hypothesis. The identification of rare variants involves the careful selection of candidate genes to examine, the availability of highly efficient resequencing techniques and the appropriate assessment of the functional consequences of the implicated variant. We believe that this strategy can be successfully applied at present in order to unravel the contribution of rare variants to the multifactorial inheritance of common diseases, which could lead to the implementation of much needed preventative screening schemes. |
23393712 | Signalling pathways activated by Rho small GTPases have recently been identified that coordinate junction assembly, stability and function, as well as interactions of adhesive complexes with the underlying cortical cytoskeleton. Particularly exciting is the interplay between adherens junctions, activation of Rho proteins and the dynamics of microtubule, actin and intermediate filaments. This interplay has important implications for functional regulation of cell-cell adhesion, and points to a more integrated view of signalling processes. |
23397658 | Fibroblast growth factor 21 (FGF21), a metabolic hormone predominantly produced by the liver, is also expressed in adipocytes and the pancreas. It regulates glucose and lipid metabolism through pleiotropic actions in these tissues and the brain. In mice, fasting leads to increased PPAR-α mediated expression of FGF21 in the liver where it stimulates gluconeogenesis, fatty acid oxidation, and ketogenesis, as an adaptive response to fasting and starvation. In the fed state, FGF21 acts as an autocrine factor in adipocytes, regulating the activity of PPAR-γ through a feed-forward loop mechanism. Administration of recombinant FGF21 has been shown to confer multiple metabolic benefits on insulin sensitivity, blood glucose, lipid profile and body weight in obese mice and diabetic monkeys, without mitogenic or other side effects. Such findings highlight the potential role of FGF21 as a therapeutic agent for obesity-related medical conditions. However, in human studies, high circulating FGF21 levels are found in obesity and its related cardiometabolic disorders including the metabolic syndrome, type 2 diabetes, non-alcoholic fatty liver disease and coronary artery disease. These findings may indicate the presence of FGF21 resistance or compensatory responses to the underlying metabolic stress, and imply the need for supraphysiological doses of FGF21 to achieve therapeutic efficacy. On the other hand, serum FGF21 has been implicated as a potential biomarker for the early detection of these cardiometabolic disorders. This review summarizes recent developments in the understanding of FGF21, from physiological and clinical perspectives. |
23400191 | AIMS There is a fivefold increase in the frequency of intracranial aneurysm (IA) in adults with coarctation of the aorta (CoA). Current guidelines for management of adults with CoA recommend computed tomography angiography (CTA) or magnetic resonance imaging of the intracranial vessels. However, this recommendation has not been universally accepted. The purpose of our study was to prospectively perform CTA of the intracranial vessels in adults with CoA to evaluate the prevalence and identify high-risk features of this complication. METHODS AND RESULTS From January 2008 to February 2011, adults ≥18 years of age with CoA were prospectively enrolled in a screening program with CTA of the intracranial vessels. Analyses of prognostic variables were performed with both Fisher's exact and two sample t-test. Forty-three patients (58% female, 33.55 ± 10.21 years) with CoA completed CTA of the intracranial vessels. Five patients (11%) were found to have IA. Patients with IA were older than those without (45.6 ± 8.17 vs. 30.89 ± 7.89, P = 0.0003). There were no statistically significant differences detected between measurements of fasting lipid profiles, C-reactive protein, brain natriuretic peptide, and homocysteine levels among CoA patients with and without IA (P = not significant). CONCLUSION Prospective screening of adults with CoA confirmed the increased prevalence of IA but also identified increased age as the sole risk factor. These data suggested that screening is justified particularly in the fourth and fifth decades of life. Further studies are required that focus on the development, natural history, and treatment of IA. |
23403754 | In this review I summarize interrelations between bioenergetic processes and such programmed death phenomena as cell suicide (apoptosis and necrosis) and mitochondrial suicide (mitoptosis). The following conclusions are made. (I) ATP and rather often mitochondrial hyperpolarization (i.e. an increase in membrane potential, ΔΨ) are required for certain steps of apoptosis and necrosis. (II) Apoptosis, even if it is accompanied by ΔΨ and [ATP] increases at its early stage, finally results in a ΔΨ collapse and ATP decrease. (III) Moderate (about three-fold) lowering of [ATP] for short and long periods of time induces apoptosis and necrosis, respectively. In some types of apoptosis and necrosis, the cell death is mediated by a ΔΨ-dependent overproduction of ROS by the initial (Complex I) and the middle (Complex III) spans of the respiratory chain. ROS initiate mitoptosis which is postulated to rid the intracellular population of mitochondria from those that are ROS overproducing. Massive mitoptosis can result in cell death due to release to cytosol of the cell death proteins normally hidden in the mitochondrial intermembrane space. |
23420615 | Nova proteins are neuron-specific antigens targeted in paraneoplastic opsoclonus myoclonus ataxia (POMA), an autoimmune neurologic disease characterized by abnormal motor inhibition. Nova proteins regulate neuronal pre-messenger RNA splicing by directly binding to RNA. To identify Nova RNA targets, we developed a method to purify protein-RNA complexes from mouse brain with the use of ultraviolet cross-linking and immunoprecipitation (CLIP).Thirty-four transcripts were identified multiple times by Nova CLIP.Three-quarters of these encode proteins that function at the neuronal synapse, and one-third are involved in neuronal inhibition. Splicing targets confirmed in Nova-/- mice include c-Jun N-terminal kinase 2, neogenin, and gephyrin; the latter encodes a protein that clusters inhibitory gamma-aminobutyric acid and glycine receptors, two previously identified Nova splicing targets. Thus, CLIP reveals that Nova coordinately regulates a biologically coherent set of RNAs encoding multiple components of the inhibitory synapse, an observation that may relate to the cause of abnormal motor inhibition in POMA. |
23420807 | Angiogenesis, the formation of new blood vessels from an existing vasculature, is requisite for tumor growth. It entails intercellular coordination of endothelial and tumor cells through angiogenic growth factor signaling. Interruption of these events has implications in the suppression of tumor growth. PD166285, a broad-spectrum receptor tyrosine kinase (RTK) inhibitor, and PD173074, a selective FGFR1TK inhibitor, were evaluated for their anti-angiogenic activity and anti-tumor efficacy in combination with photodynamic therapy (PDT). To evaluate the anti-angiogenic and anti-tumor activities of these compounds, RTK assays, in vitro tumor cell growth and microcapillary formation assays, in vivo murine angiogenesis and anti-tumor efficacy studies utilizing RTK inhibitors in combination with photodynamic therapy were performed. PD166285 inhibited PDGFR-β-, EGFR-, and FGFR1TKs and c-src TK by 50% (IC50) at concentrations between 7−85nM. PD173074 displayed selective inhibitory activity towards FGFR1TK at 26nM. PD173074 demonstrated (>100 fold) selective growth inhibitory action towards human umbilical vein endothelial cells compared with a panel of tumor cell lines. Both PD166285 and PD173074 (at 10nM) inhibited the formation of microcapillaries on Matrigel-coated plastic. In vivo anti-angiogenesis studies in mice revealed that oral administration (p.o.) of either PD166285 (1−25 mg/kg) or PD173074 (25−100 mg/kg) generated dose dependent inhibition of angiogenesis. Against a murine mammary 16c tumor, significantly prolonged tumor regressions were achieved with daily p.o. doses of PD166285 (5−10 mg/kg) or PD173074 (30−60 mg/kg) following PDT compared with PDT alone (p<0.001). Many long-term survivors were also noted in combination treatment groups. PD166285 and PD173074 displayed potent anti-angiogenic and anti-tumor activity and prolonged the duration of anti-tumor response to PDT. Interference in membrane signal transduction by inhibitors of specific RTKs (e.g. FGFR1TK) should result in new chemotherapeutic agents having the ability to limit tumor angiogenesis and regrowth following cytoreductive treatments such as PDT. |
23471400 | GOALS We investigated whether measurement of serum levels of the microRNAs (miRNAs) miR-16, miR-195, and miR-199a, alone or in combination with conventional serum markers, can help to differentiate hepatocellular carcinoma (HCC) from chronic liver diseases (CLDs). BACKGROUND Recent reports suggest a link between aberrant expression of miRNA, and HCC. STUDY This retrospective analysis was conducted using sera from 105 HCC patients, 107 CLD patients, and 71 normal control subjects. The miRNAs were measured using real-time reverse transcription-polymerase chain reaction. The conventional HCC markers α-fetoprotein (AFP), lens culinaris agglutinin-reactive AFP (AFP-L3%), and des-γ-carboxyprothrombin (DCP) were measured with commercial kits. RESULTS Serum levels of miR-16 and miR-199a were significantly lower in HCC than in CLD patients or control subjects (P<0.01). As a single marker, miR-16 had the highest sensitivity for HCC, followed by miR-199a, AFP, DCP, AFP-L3%, and miR-195. The combination of miR-16, AFP, AFP-L3%, and DCP yielded the optimal combination of sensitivity (92.4%) and specificity (78.5%) for HCC, overall and when analysis was restricted to patients with tumors size smaller than 3 cm. As a second-line HCC marker, miR-16 yielded positive HCC predictions in 18 of the 26 (69.2%) HCC patients with negative results on all 3 conventional markers, most of whom had tumors size smaller than 3 cm; miR-16 was falsely positive in only 12 of 96 (12.5%) CLD patients. CONCLUSIONS The addition of miR-16 to conventional serum markers improved sensitivity and specificity for HCC. Use of miR-16 for second-line testing in cases considered negative on the basis of conventional HCC markers should be explored in larger, prospective studies. |
23495058 | Previous studies have detected associations between mitochondrial haplogroups and schizophrenia (SZ). However, no study has examined the relationship between major mitochondrial DNA (mtDNA) haplogroups and SZ in the Chinese population. The aim of this study was to assess the association between mtDNA haplogroups and SZ genesis in the Chinese Han population. We used a case-control study and sequenced the mtDNA hypervariable regions (HVR1, HVR2, and HVR3) in the Han population. We analyzed mtDNA haplogroups and HVR polymorphisms in 298 SZ patients and 298 controls. The haplotypes were classified into 10 major haplogroups: A, B, CZ, D, F, G, M, N, N9a, and R. Statistical analysis revealed that only N9a showed a nominally significant association with protection from SZ [1.68% vs. 6.38%, p=0.004, OR=0.251 (0.092-0.680); after adjustment for age and sex: p=0.006, OR=0.246 (0.090-0.669)]. Three HVR polymorphisms were found to be nominally significantly different between subjects with SZ and controls, and all except one (m.204T>C) are linked to the N9a haplogroup. Our results indicate that mtDNA haplogroup N9a might be a protective factor for SZ. |
23509113 | Acute inflammation in the lung is essential to health. So too is its resolution. In response to invading microbes, noxious stimuli, or tissue injury, an acute inflammatory response is mounted to protect the host. To limit inflammation and prevent collateral injury of healthy, uninvolved tissue, the lung orchestrates the formation of specialized proresolving mediators, specifically lipoxins, resolvins, protectins, and maresins. These immunoresolvents are agonists for resolution that interact with specific receptors on leukocytes and structural cells to blunt further inflammation and promote catabasis. This process appears to be defective in several common lung diseases that are characterized by excess or chronic inflammation. Here, we review the molecular and cellular effectors of resolution of acute inflammation in the lung. |
23535770 | Neural stem cells are precursors of neurons and glial cells. During brain development, these cells proliferate, migrate and differentiate into specific lineages. Recently neural stem cells within the adult central nervous system were identified. Informations are now emerging about regulation of stem cell proliferation, migration and differentiation by numerous soluble factors such as chemokines and cytokines. However, the signal transduction mechanisms downstream of these factors are less clear. Here, we review potential evidences for a novel central role of the transcription factor nuclear factor kappa B (NF-kappaB) in these crucial signal transduction processes. NF-kappaB is an inducible transcription factor detected in neurons, glia and neural stem cells. NF-kappaB was discovered by David Baltimore's laboratory as a transcription factor in lymphocytes. NF-kappaB is involved in many biological processes such as inflammation and innate immunity, development, apoptosis and anti-apoptosis. It has been recently shown that members of the NF-kappaB family are widely expressed by neurons, glia and neural stem cells. In the nervous system, NF-kappaB plays a crucial role in neuronal plasticity, learning, memory consolidation, neuroprotection and neurodegeneration. Recent data suggest an important role of NF-kappaB on proliferation, migration and differentiation of neural stem cells. NF-kappaB is composed of three subunits: two DNA-binding and one inhibitory subunit. Activation of NF-kappaB takes place in the cytoplasm and results in degradation of the inhibitory subunit, thus enabling the nuclear import of the DNA-binding subunits. Within the nucleus, several target genes could be activated. In this review, we suggest a model explaining the multiple action of NF-kappaB on neural stem cells. Furthermore, we discuss the potential role of NF-kappaB within the so-called brain cancer stem cells. |
23557241 | BACKGROUND Emerging evidence suggests an association between female prenatal experience and her subsequent risk of developing breast cancer. Potential underlying mechanisms include variation in amounts of maternal endogenous sex hormones and growth hormones, germ-cell mutations, formation of cancer stem-cells, and other genetic or epigenetic events. We reviewed and summarised quantitatively the available data on intrauterine exposures and risk of breast cancer. METHODS We systematically searched for studies that assessed association between perinatal factors and risk of breast cancer. We reviewed separately each of the perinatal factors, including birthweight, birth length, parental age at delivery, gestational age, intrauterine exposure to diethylstilbestrol, twin membership, maternal pre-eclampsia or eclampsia, and other factors. FINDINGS We identified 57 studies published between Oct 1, 1980, and June 21, 2007. Increased risk of breast cancer was noted with increased birthweight (relative risk [RR] 1.15 [95% CI 1.09-1.21]), birth length (1.28 [1.11-1.48]), higher maternal age (1.13 [1.02-1.25]), and paternal age (1.12 [1.05-1.19]). Decreased risk of breast cancer was noted for maternal pre-eclampsia and eclampsia (0.48 [0.30-0.78]) and twin membership (0.93 [0.87-1.00]). No association was noted between risk of breast cancer and gestational age at birth (0.95 [0.71-1.26]) or maternal diethylstilbestrol treatment (1.40 [0.86-2.28]). INTERPRETATION The intrauterine environment contributes to the predisposition of women to breast cancer in adulthood. The in-utero mechanisms responsible for such predisposition need to be elucidated. |
23576165 | Aerobic glycolysis, i.e., the Warburg effect, may contribute to the aggressive phenotype of hepatocellular carcinoma. However, increasing evidence highlights the limitations of the Warburg effect, such as high mitochondrial respiration and low glycolysis rates in cancer cells. To explain such contradictory phenomena with regard to the Warburg effect, a metabolic interplay between glycolytic and oxidative cells was proposed, i.e., the "reverse Warburg effect". Aerobic glycolysis may also occur in the stromal compartment that surrounds the tumor; thus, the stromal cells feed the cancer cells with lactate and this interaction prevents the creation of an acidic condition in the tumor microenvironment. This concept provides great heterogeneity in tumors, which makes the disease difficult to cure using a single agent. Understanding metabolic flexibility by lactate shuttles offers new perspectives to develop treatments that target the hypoxic tumor microenvironment and overcome the limitations of glycolytic inhibitors. |
23576726 | Increased tolerance of crops to low oxygen (hypoxia) during flooding is a key target for food security. In Arabidopsis thaliana (L.) Heynh., the N-end rule pathway of targeted proteolysis controls plant responses to hypoxia by regulating the stability of group VII ethylene response factor (ERFVII) transcription factors, controlled by the oxidation status of amino terminal (Nt)-cysteine (Cys). Here, we show that the barley (Hordeum vulgare L.) ERFVII BERF1 is a substrate of the N-end rule pathway in vitro. Furthermore, we show that Nt-Cys acts as a sensor for hypoxia in vivo, as the stability of the oxygen-sensor reporter protein MCGGAIL-GUS increased in waterlogged transgenic plants. Transgenic RNAi barley plants, with reduced expression of the N-end rule pathway N-recognin E3 ligase PROTEOLYSIS6 (HvPRT6), showed increased expression of hypoxia-associated genes and altered seed germination phenotypes. In addition, in response to waterlogging, transgenic plants showed sustained biomass, enhanced yield, retention of chlorophyll, and enhanced induction of hypoxia-related genes. HvPRT6 RNAi plants also showed reduced chlorophyll degradation in response to continued darkness, often associated with waterlogged conditions. Barley Targeting Induced Local Lesions IN Genomes (TILLING) lines, containing mutant alleles of HvPRT6, also showed increased expression of hypoxia-related genes and phenotypes similar to RNAi lines. We conclude that the N-end rule pathway represents an important target for plant breeding to enhance tolerance to waterlogging in barley and other cereals. |
23577014 | During Caenorhabditis elegans oocyte meiosis, a multi-protein ring complex (RC) localized between homologous chromosomes, promotes chromosome congression through the action of the chromokinesin KLP-19. While some RC components are known, the mechanism of RC assembly has remained obscure. We show that SUMO E3 ligase GEI-17/PIAS is required for KLP-19 recruitment to the RC, and proteomic analysis identified KLP-19 as a SUMO substrate in vivo. In vitro analysis revealed that KLP-19 is efficiently sumoylated in a GEI-17-dependent manner, while GEI-17 undergoes extensive auto-sumoylation. GEI-17 and another RC component, the kinase BUB-1, contain functional SUMO interaction motifs (SIMs), allowing them to recruit SUMO modified proteins, including KLP-19, into the RC. Thus, dynamic SUMO modification and the presence of SIMs in RC components generate a SUMO-SIM network that facilitates assembly of the RC. Our results highlight the importance of SUMO-SIM networks in regulating the assembly of dynamic protein complexes. |
23604601 | The IME1 gene of Saccharomyces cerevisiae is required for initiation of meiosis. Transcription of IME1 is detected under conditions which are known to induce initiation of meiosis, namely starvation for nitrogen and glucose, and the presence of MATa1 and MAT alpha 2 gene products. In this paper we show that IME1 is also subject to translational regulation. Translation of IME1 mRNA is achieved either upon nitrogen starvation, or upon G1 arrest. In the presence of nutrients, constitutively elevated transcription of IME1 is also sufficient for the translation of IME1 RNA. Four different conditions were found to cause expression of Ime1 protein in vegetative cultures: elevated transcription levels due to the presence of IME1 on a multicopy plasmid; elevated transcription provided by a Gal-IME1 construct; G1 arrest due to alpha-factor treatment; G1 arrest following mild heat-shock treatment of cdc28 diploids. Using these conditions, we obtained evidence that starvation is required not only for transcription and efficient translation of IME1, but also for either the activation of Ime1 protein or for the induction/activation of another factor that, either alone or in combination with Ime1, induces meiosis. |
23618826 | Construction and intracellular targeting of eukaryotic pre-ribosomal particles involve a multitude of diverse transiently associating trans-acting assembly factors, energy-consuming enzymes, and transport factors. The ability to rapidly and reliably measure co-enrichment of multiple factors with maturing pre-ribosomal particles presents a major biochemical bottleneck towards revealing their function and the precise contribution of >50 energy-consuming steps that drive ribosome assembly. Here, we devised a workflow that combines genetic trapping, affinity-capture, and selected reaction monitoring mass spectrometry (SRM-MS), to overcome this deficiency. We exploited this approach to interrogate the dynamic proteome of pre-60S particles after nuclear export. We uncovered assembly factors that travel with pre-60S particles to the cytoplasm, where they are released before initiating translation. Notably, we identified a novel shuttling factor that facilitates nuclear export of pre-60S particles. Capturing and quantitating protein interaction networks of trapped intermediates of macromolecular complexes by our workflow is a reliable discovery tool to unveil dynamic processes that contribute to their in vivo assembly and transport. |
23639838 | Brain metastases occur in up to 40% of patients with cancer. Their management has been revolutionized in the last decade by three developments: improved imaging and detection of metastases, better treatment of systemic disease with the result that metastases occur more often; and improved surgical techniques including image-guided surgery to treat metastatic lesions. Class 1 data suggest that surgery is a better treatment for metastases than whole brain radiation. Other data suggest that metastases even in eloquent cortex can be removed safely. The complication rate is low and the recurrence rate is less than 10%. In general, indications for surgery include a mass with an unknown primary; a symptomatic mass including one in eloquent areas; a mass with considerable edema requiring high dose steroids; a mass greater than 3 cm; or patient preference when radiosurgery may also be an option. The question of radiosurgery or whole brain radiation as adjunct to surgical removal requires further evaluation. |
23665162 | Global DNA hypomethylation has been associated with increased risk for cancers of the colorectum, bladder, breast, head and neck, and testicular germ cells. The aim of this study was to examine whether global hypomethylation in blood leukocyte DNA is associated with the risk of hepatocellular carcinoma (HCC). A total of 315 HCC cases and 356 age-, sex- and HBsAg status-matched controls were included. Global methylation in blood leukocyte DNA was estimated by analyzing long interspersed element-1 (LINE-1) repeats using bisulfite-polymerase chain reaction (PCR) and pyrosequencing. We observed that the median methylation level in HCC cases (percentage of 5-methylcytosine (5mC)=77.7%) was significantly lower than that in controls (79.5% 5mC) (P=0.004, Wilcoxon rank-sum test). The odds ratios (ORs) of HCC for individuals in the third, second, and first (lowest) quartiles of LINE-1 methylation were 1.1 (95% confidence interval (CI) 0.7–1.8), 1.4 (95% CI 0.8–2.2), and 2.6 (95% CI 1.7–4.1) (P for trend <0.001), respectively, compared to individuals in the fourth (highest) quartile. A 1.9-fold (95% CI 1.4–2.6) increased risk of HCC was observed among individuals with LINE-1 methylation below the median compared to individuals with higher (>median) LINE-1 methylation. Our results demonstrate for the first time that individuals with global hypomethylation measured in LINE-1 repeats in blood leukocyte DNA have an increased risk for HCC. Our data provide the evidence that global hypomethylation detected in the easily obtainable DNA source of blood leukocytes may help identify individuals at risk of HCC. |
23670644 | BACKGROUND The ketogenic diet has been widely and successfully used to treat children with drug-resistant epilepsy since the 1920s. The aim of this study was to test the efficacy of the ketogenic diet in a randomised controlled trial. METHODS 145 children aged between 2 and 16 years who had at least daily seizures (or more than seven seizures per week), had failed to respond to at least two antiepileptic drugs, and had not been treated previously with the ketogenic diet participated in a randomised controlled trial of its efficacy to control seizures. Enrolment for the trial ran between December, 2001, and July, 2006. Children were seen at one of two hospital centres or a residential centre for young people with epilepsy. Children were randomly assigned to receive a ketogenic diet, either immediately or after a 3-month delay, with no other changes to treatment (control group). Neither the family nor investigators were blinded to the group assignment. Early withdrawals were recorded, and seizure frequency on the diet was assessed after 3 months and compared with that of the controls. The primary endpoint was a reduction in seizures; analysis was intention to treat. Tolerability of the diet was assessed by questionnaire at 3 months. The trial is registered with ClinicalTrials.gov, number NCT00564915. FINDINGS 73 children were assigned to the ketogenic diet and 72 children to the control group. Data from 103 children were available for analysis: 54 on the ketogenic diet and 49 controls. Of those who did not complete the trial, 16 children did not receive their intervention, 16 did not provide adequate data, and ten withdrew from the treatment before the 3-month review, six because of intolerance. After 3 months, the mean percentage of baseline seizures was significantly lower in the diet group than in the controls (62.0%vs 136.9%, 75% decrease, 95% CI 42.4-107.4%; p<0.0001). 28 children (38%) in the diet group had greater than 50% seizure reduction compared with four (6%) controls (p<0.0001), and five children (7%) in the diet group had greater than 90% seizure reduction compared with no controls (p=0.0582). There was no significant difference in the efficacy of the treatment between symptomatic generalised or symptomatic focal syndromes. The most frequent side-effects reported at 3-month review were constipation, vomiting, lack of energy, and hunger. INTERPRETATION The results from this trial of the ketogenic diet support its use in children with treatment-intractable epilepsy. FUNDING HSA Charitable Trust; Smiths Charity; Scientific Hospital Supplies; Milk Development Council. |
23698769 | DNA polymerase μ (Pol μ) is the only template-dependent human DNA polymerase capable of repairing double-strand DNA breaks (DSBs) with unpaired 3′ ends in nonhomologous end joining (NHEJ). To probe this function, we structurally characterized Pol μ's catalytic cycle for single-nucleotide incorporation. These structures indicate that, unlike other template-dependent DNA polymerases, Pol μ shows no large-scale conformational changes in protein subdomains, amino acid side chains or DNA upon dNTP binding or catalysis. Instead, the only major conformational change is seen earlier in the catalytic cycle, when the flexible loop 1 region repositions upon DNA binding. Pol μ variants with changes in loop 1 have altered catalytic properties and are partially defective in NHEJ. The results indicate that specific loop 1 residues contribute to Pol μ's unique ability to catalyze template-dependent NHEJ of DSBs with unpaired 3′ ends. |
23700330 | Angiopoietin-1 (Ang-1), a ligand of the endothelium-specific receptor Tie-2, inhibits permeability in the mature vasculature, but the mechanism remains unknown. Here we show that Ang-1 signals Rho family GTPases to organize the cytoskeleton into a junction-fortifying arrangement that enhances the permeability barrier function of the endothelium. Ang-1 phosphorylates Tie-2 and its downstream effector phosphatidylinositol 3-kinase. This induces activation of one endogenous GTPase, Rac1, and inhibition of another, RhoA. Loss of either part of this dual effect abrogates the cytoskeletal and anti-permeability actions of Ang-1, suggesting that coordinated GTPase regulation is necessary for the vessel-sealing effects of Ang-1. p190 RhoGAP, a GTPase regulatory protein, provides this coordinating function as it is phosphorylated by Ang-1 treatment, requires Rac1 activation, and is necessary for RhoA inhibition. Ang-1 prevents the cytoskeletal and pro-permeability effects of endotoxin but requires p190 RhoGAP to do so. Treatment with p190 RhoGAP small interfering RNA completely abolishes the ability of Ang-1 to rescue endotoxemia-induced pulmonary vascular leak and inflammation in mice. We conclude that Ang-1 prevents vascular permeability by regulating the endothelial cytoskeleton through coordinated and opposite effects on the Rho GTPases Rac1 and RhoA. By linking Rac1 activation and RhoA inhibition, p190 RhoGAP is critical to the protective effects of Ang-1 against endotoxin. These results provide mechanistic evidence that targeting the endothelium through Tie-2 may offer specific therapeutic strategies in life-threatening endotoxemic conditions such as sepsis and acute respiratory distress syndrome. |
23702805 | Secreted semaphorins act as guidance cues in the developing nervous system and may have additional functions in mature neurons. How semaphorins are transported and secreted by neurons is poorly understood. We find that endogenous semaphorin 3A (Sema3A) displays a punctate distribution in axons and dendrites of cultured cortical neurons. GFP-Sema3A shows a similar distribution and co-localizes with secretory vesicle cargo proteins. Live-cell imaging reveals highly dynamic trafficking of GFP-Sema3A vesicles with distinct properties in axons and dendrites regarding directionality, velocity, mobility and pausing time. In axons, most GFP-Sema3A vesicles move fast without interruption, almost exclusively in the anterograde direction, while in dendrites many GFP-Sema3A vesicles are stationary and move equally frequent in both directions. Disruption of microtubules, but not of actin filaments, significantly impairs GFP-Sema3A transport. Interestingly, depolarization induces a reversible arrest of axonal transport of GFP-Sema3A vesicles but has little effect on dendritic transport. Conversely, action potential blockade using tetrodotoxin (TTX) accelerates axonal transport, but not dendritic transport. These data indicate that axons and dendrites regulate trafficking of Sema3A and probably other secretory vesicles in distinct ways, with axons specializing in fast, uninterrupted, anterograde transport. Furthermore, neuronal activity regulates secretory vesicle trafficking in axons by a depolarization-evoked trafficking arrest. |
23716150 | Cardiac chamber-specific gene expression is critical for the normal development and function of the heart. To investigate the genetic basis of cardiac anatomical specialization, we have undertaken a nearly genome-wide transcriptional profiling of the four heart chambers and the interventricular septum. Rigorous statistical analysis has allowed the identification of known and novel members of gene families that are felt to be important in cardiac development and function, including LIM proteins, homeobox proteins, wnt and T-box pathway proteins, as well as structural proteins like actins and myosins. In addition, these studies have allowed the identification of thousands of additional differentially expressed genes, for which there is little structural or functional information. Clustering of genes with known and unknown functions provides insights into signaling pathways that are essential for development and maintenance of chamber-specific features. To facilitate future research in this area, a searchable internet database has been constructed that allows study of the chamber-specific expression of any gene represented on this comprehensive microarray. It is anticipated that further study of genes identified through this effort will provide insights into the specialization of heart chamber tissues, and their specific roles in cardiac development, aging, and disease. |
23727313 | MicroRNAs (miRNAs) are a recently identified class of epigenetic elements consisting of small noncoding RNAs that bind to the 3' untranslated region of mRNAs and down-regulate their translation to protein. miRNAs play critical roles in many different cellular processes including metabolism, apoptosis, differentiation, and development. We found 33 miRNAs expressed in CD34+ hematopoietic stem-progenitor cells (HSPCs) from normal human bone marrow and mobilized human peripheral blood stem cell harvests. We then combined these data with human HSPC mRNA expression data and with miRNA-mRNA target predictions, into a previously undescribed miRNA:mRNA interaction database called the Transcriptome Interaction Database. The in silico predictions from the Transcriptome Interaction Database pointed to miRNA control of hematopoietic differentiation through translational control of mRNAs critical to hematopoiesis. From these predictions, we formulated a model for miRNA control of stages of hematopoiesis in which many of the genes specifying hematopoietic differentiation are expressed by HSPCs, but are held in check by miRNAs until differentiation occurs. We validated miRNA control of several of these target mRNAs by demonstrating that their translation in fact is decreased by miRNAs. Finally, we chose miRNA-155 for functional characterization in hematopoiesis, because we predicted that it would control both myelopoiesis and erythropoiesis. As predicted, miRNA-155 transduction greatly reduced both myeloid and erythroid colony formation of normal human HSPCs. |
23737024 | Two studies were performed to investigate the effects of an acute bout of physical exercise on the nuclear protein kappaB (NF-kappaB) signaling pathway in rat skeletal muscle. In Study 1, a group of rats (n=6) was run on the treadmill at 25 m/min, 5% grade, for 1 h or until exhaustion (Ex), and compared with a second group (n=6) injected with two doses of pyrrolidine dithiocarbamate (PDTC, 100 mg/kg, i.p.) 24 and 1 h prior to the acute exercise bout. Three additional groups of rats (n=6) were injected with either 8 mg/kg (i.p.) of lipopolysaccharide (LPS), 1 mmol/kg (i.p.) t-butylhydroperoxide (tBHP), or saline (C) and killed at resting condition. Ex rats showed higher levels of NF-kappaB binding and P50 protein content in muscle nuclear extracts compared with C rats. Cytosolic IkappaBalpha and IkappaB kinase (IKK) contents were decreased, whereas phospho-IkappaBalpha and phospho-IKK contents were increased, comparing Ex vs. C. The exercise-induced activation of NF-kappaB signaling cascade was partially abolished by PDTC treatment. LPS, but not tBHP, treatment mimicked and exaggerated the effects observed in Ex rats. In Study 2, the time course of exercise-induced NF-kappaB activation was examined. Highest levels of NF-kappaB binding were observed at 2 h postexercise. Decreased cytosolic IkappaBalpha and increased phosphor-IkappaBalpha content were found 0-1 h postexercise whereas P65 reached peak levels at 2-4 h. These data suggest that the NF-kappaB signaling pathway can be activated in a redox-sensitive manner during muscular contraction, presumably due to increased oxidant production. The cascade of intracellular events may be the overture to elevated gene expression of manganese superoxide dismutase reported earlier (Pfluegers Arch. 442, 426-434, 2001). |
23746313 | Staphylococcus aureus RNAIII is one of the largest regulatory RNAs, which controls several virulence genes encoding exoproteins and cell-wall-associated proteins. One of the RNAIII effects is the repression of spa gene (coding for the surface protein A) expression. Here, we show that spa repression occurs not only at the transcriptional level but also by RNAIII-mediated inhibition of translation and degradation of the stable spa mRNA by the double-strand-specific endoribonuclease III (RNase III). The 3' end domain of RNAIII, partially complementary to the 5' part of spa mRNA, efficiently anneals to spa mRNA through an initial loop-loop interaction. Although this annealing is sufficient to inhibit in vitro the formation of the translation initiation complex, the coordinated action of RNase III is essential in vivo to degrade the mRNA and irreversibly arrest translation. Our results further suggest that RNase III is recruited for targeting the paired RNAs. These findings add further complexity to the expression of the S. aureus virulon. |
23763738 | We have developed a rapid, sensitive, and inexpensive method for measuring the cellular protein content of adherent and suspension cultures in 96-well microtiter plates. The method is suitable for ordinary laboratory purposes and for very large-scale applications, such as the National Cancer Institute's disease-oriented in vitro anticancer-drug discovery screen, which requires the use of several million culture wells per year. Cultures fixed with trichloroacetic acid were stained for 30 minutes with 0.4% (wt/vol) sulforhodamine B (SRB) dissolved in 1% acetic acid. Unbound dye was removed by four washes with 1% acetic acid, and protein-bound dye was extracted with 10 mM unbuffered Tris base [tris (hydroxymethyl)aminomethane] for determination of optical density in a computer-interfaced, 96-well microtiter plate reader. The SRB assay results were linear with the number of cells and with values for cellular protein measured by both the Lowry and Bradford assays at densities ranging from sparse subconfluence to multilayered supraconfluence. The signal-to-noise ratio at 564 nm was approximately 1.5 with 1,000 cells per well. The sensitivity of the SRB assay compared favorably with sensitivities of several fluorescence assays and was superior to those of both the Lowry and Bradford assays and to those of 20 other visible dyes. The SRB assay provides a colorimetric end point that is nondestructive, indefinitely stable, and visible to the naked eye. It provides a sensitive measure of drug-induced cytotoxicity, is useful in quantitating clonogenicity, and is well suited to high-volume, automated drug screening. SRB fluoresces strongly with laser excitation at 488 nm and can be measured quantitatively at the single-cell level by static fluorescence cytometry. |
23777820 | Myeloma causes a devastating and unique form of osteolytic bone disease. Although osteoclast activation is responsible for bone destruction, the precise mechanisms by which myeloma cells increase osteoclast activity have not been defined. An animal model of human myeloma bone disease would help in clarification of these mechanisms. Multiple myeloma occurs spontaneously in aging C57 BL/KaLwRij mice and has all of the features of the disease in humans, including the characteristic bone lesions. The disease can be induced in normal C57 BL/KaLwRij mice by inoculation of fresh marrow-derived cells from mice with myeloma, but this model is difficult to study because of variability in the number of myeloma cells in marrow-derived preparations. To develop a better animal model of human myeloma bone disease, we have established and subcloned a cell line from this murine myeloma and found that it causes osteolytic bone lesions in mice characteristic of human myeloma bone disease. The cell line produces interleukin-6, but grows independent of exogenous interleukin-6. Mice inoculated intravenously with the cultured cells predictably develop an identical disease to the mice injected intravenously with fresh bone-marrow-derived myeloma cells, including monoclonal gammopathy and radiologic bone lesions. We found that some of the mice became hypercalcemic, and the bone lesions are characterized by increased osteoclast activity. We found identical results when we inoculated Nu/Bg/XID mice with cultured murine myeloma cells. Because we can inoculate mice with precise numbers of cells and predict accurately when the mice will develop bone lesions, become hypercalcemic, and die, this should be a convenient model for determining the mechanisms by which the myeloma cells cause osteoclast activation in this model of human myeloma bone disease. |
23783727 | AIMS patients with diabetes mellitus (DM) have high platelet reactivity and are at increased risk of ischaemic events and bleeding post-acute coronary syndromes (ACS). In the PLATelet inhibition and patient Outcomes (PLATO) trial, ticagrelor reduced the primary composite endpoint of cardiovascular death, myocardial infarction, or stroke, but with similar rates of major bleeding compared with clopidogrel. We aimed to investigate the outcome with ticagrelor vs. clopidogrel in patients with DM or poor glycaemic control. METHODS AND RESULTS we analysed patients with pre-existing DM (n = 4662), including 1036 patients on insulin, those without DM (n = 13 951), and subgroups based on admission levels of haemoglobin A1c (HbA1c; n = 15 150). In patients with DM, the reduction in the primary composite endpoint (HR: 0.88, 95% CI: 0.76-1.03), all-cause mortality (HR: 0.82, 95% CI: 0.66-1.01), and stent thrombosis (HR: 0.65, 95% CI: 0.36-1.17) with no increase in major bleeding (HR: 0.95, 95% CI: 0.81-1.12) with ticagrelor was consistent with the overall cohort and without significant diabetes status-by-treatment interactions. There was no heterogeneity between patients with or without ongoing insulin treatment. ticagrelor reduced the primary endpoint, all-cause mortality, and stent thrombosis in patients with HbA1c above the median (HR: 0.80, 95% CI: 0.70-0.91; HR: 0.78, 95% CI: 0.65-0.93; and HR: 0.62, 95% CI: 0.39-1.00, respectively) with similar bleeding rates (HR: 0.98, 95% CI: 0.86-1.12). CONCLUSION ticagrelor, when compared with clopidogrel, reduced ischaemic events in ACS patients irrespective of diabetic status and glycaemic control, without an increase in major bleeding events. |
23785605 | BACKGROUND Migraine, particularly with aura, is a risk factor for early-onset ischemic stroke. The underlying mechanisms are unknown, but may in part be due to migraineurs having an increased risk profile for cardiovascular disease. In this study, the authors compare the cardiovascular risk profile of adult migraineurs to that of nonmigraineurs. METHODS Participants (n = 5,755, 48% men, age 20 to 65 years) are from the Genetic Epidemiology of Migraine (GEM) study, a population-based study in the Netherlands. A total of 620 current migraineurs were identified: 31% with aura (MA), 64% without aura (MO), and 5% unclassified. Controls were 5,135 individuals without lifetime migraine. Measured cardiovascular risk factors included blood pressure (BP), serum total and high-density lipoprotein cholesterol (TC, HDL), smoking, oral contraceptive use, and the Framingham risk score for myocardial infarction or coronary heart disease (CHD) death. RESULTS Compared to controls, migraineurs were more likely to smoke (OR = 1.43 [1.1 to 1.8]), less likely to consume alcohol (OR = 0.58 [0.5 to 0.7]), and more likely to report a parental history of early myocardial infarction. Migraineurs with aura were more likely to have an unfavorable cholesterol profile (TC > or = 240 mg/dL [OR = 1.43 (0.97 to 2.1)], TC:HDL ratio > 5.0 [OR = 1.64 (1.1 to 2.4)]), have elevated BP (systolic BP > 140 mm Hg or diastolic BP > 90 mm Hg [OR = 1.76 (1.04 to 3.0)]), and report a history of early onset CHD or stroke (OR = 3.96 [1.1 to 14.3]); female migraineurs with aura were more likely to be using oral contraceptives (OR = 2.06 [1.05 to 4.0]). The odds of having an elevated Framingham risk score for CHD were approximately doubled for the migraineurs with aura. CONCLUSIONS Migraineurs, particularly with aura, have a higher cardiovascular risk profile than individuals without migraine. |
23801039 | Despite many years of study, relatively little is known about the effector mechanisms that operate against intestine-dwelling nematodes. Most of the current understanding comes from studies of laboratory model systems in rodents. It is clear that when an intestinal helminth infection takes place the immune system generates a strong Th2-mediated response, which regulates a variety of responses characteristic of helminth infections such as eosinophilia, intestinal mastocytosis and elevated IgE production. The ability to modulate the host's immune response in vivo with cytokine-specific monoclonal antibodies and recombinant cytokines, together with the use of animals with disruption of key genes involved in the immune response, have provided powerful tools with which to dissect the potential effector mechanisms operating. In the absence of a T-cell compartment the host is unable to expel the parasite. If a Th1-dominated response is generated, protective immunity is almost universally compromised. Thus, it it would appear that some aspect of a Th2-mediated response controls effector mechanisms. Although it is clear that for some infections the mast cell appears to be involved in protection, probably through the generation of a non-specific inflammatory response, how these cells become activated remains unclear. Data from infections in transgenic animals suggest that activation is not through the high-affinity receptor for IgE. Such studies also call into doubt the importance of conventional interactions between effector leucocytes and antibody. There is little evidence to support a protective role for eosinophilia in any system. New data also imply that, although interleukin 4 (IL-4) is generally important (and can exert effects independent of an adaptive immune response), it is not always sufficient to mediate protection; other Th2 cytokines (e.g. IL-13) may warrant closer investigation. It is apparent that a number of potential Th2-controlled effector mechanisms (some of which may be particularly important at mucosal surfaces) remain to be explored. Overall, it is likely that worm expulsion is the result of a combination of multiple mechanisms, some of which are more critical to some species of parasite than to others. |
23816832 | Diagnosis of multiple sclerosis (MS) requires the exclusion of other possible diagnoses. For this reason, the cerebrospinal fluid (CSF) should be routinely analysed in patients with a first clinical event suggestive of MS. CSF analysis is no longer mandatory for diagnosis of relapsing–remitting MS, as long as MRI diagnostic criteria are fulfilled. However, caution is required in diagnosing MS in patients with negative MRI findings or in the absence of CSF analysis, as CSF investigation is useful to eliminate other causes of disease. The detection of oligoclonal IgG bands in CSF has potential prognostic value and is helpful for clinical decision-making. In addition, CSF analysis is important for research into the pathogenesis of MS. Pathophysiological and neurodegenerative findings of inflammation in MS have been derived from CSF investigations. Novel CSF biomarkers, though not yet validated, have been identified for diagnosis of MS and for ascertaining disease activity, prognosis and response to treatment, and are likely to increase in number with modern detection techniques. In this Review, we summarize CSF findings that shed light on the differential diagnosis of MS, and highlight the potential of novel biomarkers for this disease that could advance understanding of its pathophysiology. |
23841828 | The extensive computerisation of Danish pharmacies has permitted the establishment of two large prescription registries: The Odense University Pharmacoepidemiological Database (OPED) and the Pharmacoepidemiological Prescription Database of North Jutland (PDNJ). The Danish prescription registries content, coverage, completeness and the quality of the data are discussed in this article. Furthermore, conditions for access to the data are presented. The two prescription registries cover a background population of approximately one million or 18% of the Danish population. The populations covered by the registries are stable and representative of the Danish population in general. The registries cover all reimbursed medicine at the level of the individual user. Registration of a unique and permanent personal identifier enables the compilation of longitudinal drug histories and allows the linking of prescription data to other population-based Danish registries. The degree of completeness of the Danish prescription registries is excellent for reimbursed prescription drugs. A small number of comparison studies also indicate high validity of the register information. The Danish prescription registries represent a useful new data source for pharmacoepidemiological studies. |
23863551 | We examined the effects of an inhibitor of PI3K, XL147, against human breast cancer cell lines with constitutive PI3K activation. Treatment with XL147 resulted in dose-dependent inhibition of cell growth and levels of pAKT and pS6, signal transducers in the PI3K/AKT/TOR pathway. In HER2-overexpressing cells, inhibition of PI3K was followed by up-regulation of expression and phosphorylation of multiple receptor tyrosine kinases, including HER3. Knockdown of FoxO1 and FoxO3a transcription factors suppressed the induction of HER3, InsR, IGF1R, and FGFR2 mRNAs upon inhibition of PI3K. In HER2(+) cells, knockdown of HER3 with siRNA or cotreatment with the HER2 inhibitors trastuzumab or lapatinib enhanced XL147-induced cell death and inhibition of pAKT and pS6. Trastuzumab and lapatinib each synergized with XL147 for inhibition of pAKT and growth of established BT474 xenografts. These data suggest that PI3K antagonists will inhibit AKT and relieve suppression of receptor tyrosine kinase expression and their activity. Relief of this feedback limits the sustained inhibition of the PI3K/AKT pathway and attenuates the response to these agents. As a result, PI3K pathway inhibitors may have limited clinical activity overall if used as single agents. In patients with HER2-overexpressing breast cancer, PI3K inhibitors should be used in combination with HER2/HER3 antagonists. |
23863576 | UNLABELLED Morphological characteristics of dendritic spines form the basis of cognitive ability. However, molecular mechanisms involved in fine-tuning of spine morphology during development are not fully understood. Moreover, it is unclear whether, and to what extent, these developmental mechanisms determine the normal adult spine morphological features. Here, we provide evidence that α2-isoform of Rac-specific GTPase-activating protein α-chimaerin (α2-chimaerin) is involved in spine morphological refinement during late postnatal period, and furthermore show that this developmental α2-chimaerin function affects adult spine morphologies. We used a series of mice with global and conditional knock-out of α-chimaerin isoforms (α1-chimaerin and α2-chimaerin). α2-Chimaerin disruption, but not α1-chimaerin disruption, in the mouse results in an increased size (and density) of spines in the hippocampus. In contrast, overexpression of α2-chimaerin in developing hippocampal neurons induces a decrease of spine size. Disruption of α2-chimaerin suppressed EphA-mediated spine morphogenesis in cultured developing hippocampal neurons. α2-Chimaerin disruption that begins during the juvenile stage results in an increased size of spines in the hippocampus. Meanwhile, spine morphologies are unaltered when α2-chimaerin is deleted only in adulthood. Consistent with these spine morphological results, disruption of α2-chimaerin beginning in the juvenile stage led to an increase in contextual fear learning in adulthood; whereas contextual learning was recently shown to be unaffected when α2-chimaerin was deleted only in adulthood. Together, these results suggest that α2-chimaerin signaling in developmental stages contributes to determination of the morphological features of adult spines and establishment of normal cognitive ability. SIGNIFICANCE STATEMENT Recent studies of neurodevelopmental disorders in humans and their animal models have led to an attractive hypothesis that spine morphogenesis during development forms the basis of adult cognition. In particular, the roles of Rac and its regulators, such as Rac-specific GTPase-activating proteins (RacGAPs) and Rac guanine nucleotide exchange factors, are a topic of focus in spine morphogenesis and cognitive ability. Using a series of mice with global and conditional knock-out (KO) of RacGAP α-chimaerin isoforms (α1-chimaerin and α2-chimaerin), we provide compelling evidence demonstrating that α2-chimaerin is involved in spine morphological refinement during late postnatal development and that this developmental α2-chimaerin function affects adult spine morphologies. Furthermore, our results clearly showed that α2-chimaerin signaling during late postnatal development contributes to normal cognitive ability in adult mice. |
23887844 | Neurons and cancer cells use glucose extensively, yet the precise advantage of this adaptation remains unclear. These two seemingly disparate cell types also show an increased regulation of the apoptotic pathway, which allows for their long-term survival. Here we show that both neurons and cancer cells strictly inhibit cytochrome c-mediated apoptosis by a mechanism dependent on glucose metabolism. We report that the pro-apoptotic activity of cytochrome c is influenced by its redox state and that increases in reactive oxygen species (ROS) following an apoptotic insult lead to the oxidation and activation of cytochrome c. In healthy neurons and cancer cells, however, cytochrome c is reduced and held inactive by intracellular glutathione (GSH), generated as a result of glucose metabolism by the pentose phosphate pathway. These results uncover a striking similarity in apoptosis regulation between neurons and cancer cells and provide insight into an adaptive advantage offered by the Warburg effect for cancer cell evasion of apoptosis and for long-term neuronal survival. |
23895668 | Mutations in cancer reprogram amino acid metabolism to drive tumor growth, but the molecular mechanisms are not well understood. Using an unbiased proteomic screen, we identified mTORC2 as a critical regulator of amino acid metabolism in cancer via phosphorylation of the cystine-glutamate antiporter xCT. mTORC2 phosphorylates serine 26 at the cytosolic N terminus of xCT, inhibiting its activity. Genetic inhibition of mTORC2, or pharmacologic inhibition of the mammalian target of rapamycin (mTOR) kinase, promotes glutamate secretion, cystine uptake, and incorporation into glutathione, linking growth factor receptor signaling with amino acid uptake and utilization. These results identify an unanticipated mechanism regulating amino acid metabolism in cancer, enabling tumor cells to adapt to changing environmental conditions. |
23901235 | Neurogenesis occurs in the hippocampus of the developing and adult brain due to the presence of multipotent stem cells and restricted precursor cells at different stages of differentiation. It has been proposed that they may be of potential benefit for use in cell transplantation approaches for neurodegenerative disorders and trauma. Prolonged release of interleukin-1β (IL-1β) from activated microglia has a deleterious effect on hippocampal neurons and is implicated in the impaired neurogenesis and cognitive dysfunction associated with aging, Alzheimer's disease and depression. This study assessed the effect of IL-1β on the proliferation and differentiation of embryonic rat hippocampal NPCs in vitro. We show that IL-1R1 is expressed on proliferating NPCs and that IL-1β treatment decreases cell proliferation and neurosphere growth. When NPCs were differentiated in the presence of IL-1β, a significant reduction in the percentages of newly-born neurons and post-mitotic neurons and a significant increase in the percentage of astrocytes was observed in these cultures. These effects were attenuated by IL-1 receptor antagonist. These data reveal that IL-1β exerts an anti-proliferative, anti-neurogenic and pro-gliogenic effect on embryonic hippocampal NPCs, which is mediated by IL-1R1. The present results emphasise the consequences of an inflammatory environment during NPC development, and indicate that strategies to inhibit IL-1β signalling may be necessary to facilitate effective cell transplantation approaches or in conditions where endogenous hippocampal neurogenesis is impaired. |
23912923 | V domain-containing Ig suppressor of T-cell activation (VISTA) is a negative checkpoint regulator that suppresses T cell-mediated immune responses. Previous studies using a VISTA-neutralizing monoclonal antibody show that VISTA blockade enhances T-cell activation. The current study describes a comprehensive characterization of mice in which the gene for VISTA has been deleted. Despite the apparent normal hematopoietic development in young mice, VISTA genetic deficiency leads to a gradual accumulation of spontaneously activated T cells, accompanied by the production of a spectrum of inflammatory cytokines and chemokines. Enhanced T-cell responsiveness was also observed upon immunization with neoantigen. Despite the presence of multiorgan chronic inflammation, aged VISTA-deficient mice did not develop systemic or organ-specific autoimmune disease. Interbreeding of the VISTA-deficient mice with 2D2 T-cell receptor transgenic mice, which are predisposed to the development of experimental autoimmune encephalomyelitis, drastically enhanced disease incidence and intensity. Disease development is correlated with the increase in the activation of encephalitogenic T cells in the periphery and enhanced infiltration into the CNS. Taken together, our data suggest that VISTA is a negative checkpoint regulator whose loss of function lowers the threshold for T-cell activation, allowing for an enhanced proinflammatory phenotype and an increase in the frequency and intensity of autoimmunity under susceptible conditions. |
23959496 | Polycomb repressive complex two (PRC2) has been implicated in embryonic stem (ES) cell pluripotency; however, the mechanistic roles of this complex are unclear. It was assumed that ES cells contain PRC2 with the same subunit composition as that identified in HeLa cells and Drosophila embryos. Here, we report that PRC2 in mouse ES cells contains at least three additional subunits: JARID2, MTF2, and a novel protein denoted esPRC2p48. JARID2, MTF2, and esPRC2p48 are highly expressed in mouse ES cells compared to differentiated cells. Importantly, knockdowns of JARID2, MTF2, or esPRC2p48 alter the level of PRC2-mediated H3K27 methylation and result in the expression of differentiation-associated genes in ES cells. Interestingly, expression of JARID2, MTF2, and esPRC2p48 together, but not individually, enhances Oct4/Sox2/Klf4-mediated reprogramming of mouse embryonic fibroblasts (MEFs) into induced pluripotent stem cells, whereas knockdown or knockout of JARID2, MTF2, or esPRC2p48 significantly inhibits reprogramming. JARID2, MTF2, and esPRC2p48 modulate H3K27 methylation and facilitate repression of lineage-associated gene expression when transduced into MEFs, and synergistically stimulate the histone methyltransferase activity of PRC2 in vitro. Therefore, these studies identify JARID2, MTF2, and esPRC2p48 as important regulatory subunits of PRC2 in ES cells and reveal critical functions of these subunits in modulating PRC2's activity and gene expression both in ES cells and during somatic cell reprogramming. |