During development of the mammalian central nervous system (CNS), neurons and glial cells (astrocytes and oligodendrocytes) are generated from common neural precursor cells (NPCs). However, neurogenesis precedes gliogenesis, which normally commences at later stages of fetal telencephalic development. Astrocyte differentiation of mouse NPCs at embryonic day (E) 14.5 (relatively late gestation) is induced by activation of the transcription factor STAT3, whereas at E11.5 (mid-gestation) NPCs do not differentiate into astrocytes even when stimulated by STAT3-activating cytokines such as leukemia inhibitory factor (LIF). This can be explained in part by the fact that astrocyte-specific gene promoters are highly methylated in NPCs at E11.5, but other mechanisms are also likely to play a role. We therefore sought to identify genes involved in the inhibition of astrocyte differentiation of NPCs at midgestation. We first examined gene expression profiles in E11.5 and E14.5 NPCs, using Affymetrix GeneChip analysis, applying the Percellome method to normalize gene expression level. We then conducted in situ hybridization analysis for selected genes found to be highly expressed in NPCs at midgestation. Among these genes, we found that N-myc and high mobility group AT-hook 2 (Hmga2) were highly expressed in the E11.5 but not the E14.5 ventricular zone of mouse brain, where NPCs reside. Transduction of N-myc and Hmga2 by retroviruses into E14.5 NPCs, which normally differentiate into astrocytes in response to LIF, resulted in suppression of astrocyte differentiation. However, sustained expression of N-myc and Hmga2 in E11.5 NPCs failed to maintain the hypermethylated status of an astrocyte-specific gene promoter. Taken together, our data suggest that astrocyte differentiation of NPCs is regulated not only by DNA methylation but also by genes whose expression is controlled spatio-temporally during brain development.
Identification of genes that restrict astrocyte differentiation of midgestational neural precursor cells.
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View SamplesBisphenol A (BPA), an endocrine-disrupting chemical (EDC), is a well-known, ubiquitous estrogenic chemical. To investigate the effects of fetal exposure to low-dose BPA on the development of the prostate, we first examined the alterations of in situ sex steroid hormonal environment in the mouse urogenital sinus (UGS).
Endocrine disrupter bisphenol A increases in situ estrogen production in the mouse urogenital sinus.
Specimen part
View SamplesSTAT3, an essential transcription factor with pleiotropic functions, plays critical roles in the pathogenesis of autoimmunity. Despite recent data linking STAT3 with inflammatory bowel disease, exactly how it contributes to chronic intestinal inflammation is not known. Using a T cell transfer model of colitis we found that STAT3 expression in T cells was essential for the induction of both colitis and systemic inflammation. STAT3 was critical in modulating the balance of T helper 17 (Th17) and regulatory T (Treg) cells, as well as in promoting CD4+ T cell proliferation. We used chromatin immunoprecipitation and massive parallel sequencing (ChIP-Seq) to define the genome-wide targets of STAT3 in CD4+ T cells. We found that STAT3 bound to multiple genes involved in Th17 cell differentiation, cell activation, proliferation and survival, regulating both expression and epigenetic modifications. Thus, STAT3 orchestrates multiple critical aspects of T cell function in inflammation and homeostasis.
Diverse targets of the transcription factor STAT3 contribute to T cell pathogenicity and homeostasis.
Specimen part
View SamplesSTAT3, an essential transcription factor with pleiotropic functions, plays critical roles in the pathogenesis of autoimmunity. Despite recent data linking STAT3 with inflammatory bowel disease, exactly how it contributes to chronic intestinal inflammation is not known. Using a T cell transfer model of colitis we found that STAT3 expression in T cells was essential for the induction of both colitis and systemic inflammation. STAT3 was critical in modulating the balance of T helper 17 (Th17) and regulatory T (Treg) cells, as well as in promoting CD4+ T cell proliferation. We used chromatin immunoprecipitation and massive parallel sequencing (ChIP-Seq) to define the genome-wide targets of STAT3 in CD4+ T cells. We found that STAT3 bound to multiple genes involved in Th17 cell differentiation, cell activation, proliferation and survival, regulating both expression and epigenetic modifications. Thus, STAT3 orchestrates multiple critical aspects of T cell function in inflammation and homeostasis.
Diverse targets of the transcription factor STAT3 contribute to T cell pathogenicity and homeostasis.
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View SamplesInterleukin 2 (IL-2), a cytokine linked to human autoimmune diseases, limits IL-17 production. We show that deletion of Stat3 in T cells abrogates IL-17 production and attenuates autoimmunity associated with IL-2 deficiency. While STAT3 induces IL-17 and RORt and inhibits Foxp3, IL-2 inhibited IL-17 independently of Foxp3 and RORt. We found that STAT3 and STAT5 bound to multiple common sites across the Il17 genetic locus. The induction of STAT5 binding by IL-2 was associated with a reduction in STAT3 binding at these sites and the inhibition of associated active epigenetic marks. Titrating the relative activation of STAT3 and STAT5 modulated TH17 cell specification. Thus, the balance rather than the absolute magnitude of these signals determines the propensity of cells to make a key inflammatory cytokine.
Opposing regulation of the locus encoding IL-17 through direct, reciprocal actions of STAT3 and STAT5.
Specimen part
View SamplesOur previous study revealed that the basic helix-loop-helix transcription factor Hand2 is a downstream target of progesterone signaling in mouse uterine stroma at the time of implantation. Further, conditional deletion of Hand2 in mouse uterus leads to implantation failure due to impaired uterine epithelial receptivity.
The antiproliferative action of progesterone in uterine epithelium is mediated by Hand2.
Specimen part, Disease
View SamplesCD4+ T cells that selectively produce interleukin (IL)-17, are critical for host defense and autoimmunity1-4. Crucial for T helper17 (Th17) cells in vivo5,6, IL-23 has been thought to be incapable of driving initial differentiation. Rather, IL-6 and transforming growth factor (TGF)-1 have been argued to be the factors responsible for initiating specification7-10. Herein, we show that Th17 differentiation occurs in the absence of TGF- signaling. Neither IL-6 nor IL-23 alone efficiently generated Th17 cells; however, these cytokines in combination with IL-1 effectively induced IL-17 production in nave precursors, independently of TGF-. Epigenetic modification of the Il17a/Il17f and Rorc promoters proceeded without TGF-1, allowing the generation of cells that co-expressed Rort and T-bet. T-bet+Rort+ Th17 cells are generated in vivo during experimental allergic encephalomyelitis (EAE), and adoptively transferred Th17 cells generated with IL-23 in the absence of TGF-1 were more pathogenic in this experimental disease. These data suggest a new model for Th17 differentiation. Consistent with genetic data linking the IL23R with autoimmunity, our findings re-emphasize the role of IL-23 and therefore have important implications for the development of new therapies.
Generation of pathogenic T(H)17 cells in the absence of TGF-β signalling.
Treatment
View SamplesThe onset of the liver inflamentation in the Sox17+/- embryos.
Sox17 haploinsufficiency results in perinatal biliary atresia and hepatitis in C57BL/6 background mice.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Sirt1 Regulates DNA Methylation and Differentiation Potential of Embryonic Stem Cells by Antagonizing Dnmt3l.
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View SamplesStem-cells and transformed cancer cells specifically express a polycomb repressive complex subtype, PRC4 which characteristically contains Sirt1 (Sirtuin-1), a NAD+ dependent class III histone deacetylase (HDAC) and Eed2 isoform as specific members. Analyzing the transcriptiome and methylome analysis of Sirt1 deficient murine ESCs (Sirt1-/- ESC), we demonstrate that these cells repressed specifically on some genomic imprinted and germ-line related genes.
Sirt1 Regulates DNA Methylation and Differentiation Potential of Embryonic Stem Cells by Antagonizing Dnmt3l.
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