Project description:Gene expression in livers of adult male mice subjected to continuous GH infusion using Alzet osmotic minipumps for 1, 4 or 7 days was assayed by RNA-seq, as part of a study of growth hormone regulation of hepatic lincRNAs (PMID:26459762) and protein-coding genes (PMID:28694329).
Project description:We have used a simple and efficient method to identify condition-specific transcriptional regulatory sites in vivo to help elucidate the molecular basis of sex-differences in transcription, which are widespread in mammalian tissues and affect normal physiology, drug response, inflammation and disease. To systematically uncover transcriptional regulators responsible for these differences, we used DNase hypersensitivity analysis coupled with high-throughput sequencing to produce condition-specific maps of regulatory sites in male and female mouse liver, and for livers of male mice feminized by continuous infusion of growth hormone (GH). We identified 71,264 hypersensitive sites, with 1,284 showing robust sex-differences. Continuous GH infusion suppressed the vast majority of male-specific sites and induced a subset of female-specific sites in male liver. We also identified broad genomic regions (up to ~100kb) showing sex-dependent hypersensitivity and similar patterns of GH response. We found a strong association of sex-specific sites with sex-specific transcription; however, a majority of sex-specific sites were >100kb from sex-specific genes. By analyzing sequence motifs within regulatory regions, we identified two known regulators of liver sexual dimorphism, and several new candidates for further investigation. This approach can readily be applied to mapping condition-specific regulatory sites in mammalian tissues under a wide variety of physiological conditions. Global DNase Hypersensitivity in male, female, and continuous growth hormone-treated male mouse liver tissue. 10 samples: Male liver (2 replicates), Female liver (2 replicates), GH-treated male liver (2 replicates), DNase digested genomic control (from male and female liver separately) and sonicated genomic control (from male and female liver separately).
Project description:Effect of continuous GH treatment on old rat liver. Male rats, 2-year-old, were treated with vehicle or human GH (0.34 microgram/gram body weight) for 3 weeks. Keywords: response of old rat liver to growth hormone
Project description:We have used a simple and efficient method to identify condition-specific transcriptional regulatory sites in vivo to help elucidate the molecular basis of sex-differences in transcription, which are widespread in mammalian tissues and affect normal physiology, drug response, inflammation and disease. To systematically uncover transcriptional regulators responsible for these differences, we used DNase hypersensitivity analysis coupled with high-throughput sequencing to produce condition-specific maps of regulatory sites in male and female mouse liver, and for livers of male mice feminized by continuous infusion of growth hormone (GH). We identified 71,264 hypersensitive sites, with 1,284 showing robust sex-differences. Continuous GH infusion suppressed the vast majority of male-specific sites and induced a subset of female-specific sites in male liver. We also identified broad genomic regions (up to ~100kb) showing sex-dependent hypersensitivity and similar patterns of GH response. We found a strong association of sex-specific sites with sex-specific transcription; however, a majority of sex-specific sites were >100kb from sex-specific genes. By analyzing sequence motifs within regulatory regions, we identified two known regulators of liver sexual dimorphism, and several new candidates for further investigation. This approach can readily be applied to mapping condition-specific regulatory sites in mammalian tissues under a wide variety of physiological conditions.
Project description:A series of dual-channel gene expression profiles obtained using MWG Rat 5K microarrays (~5535 unique rat genes) and MWG Rat Liver microarrays (~1353 unique rat genes with 999 of these genes also represented on the Rat 5K microarray) was used to examine the sex-dependent and GH-dependent differences in gene expression in adult rat liver. This series is comprised of 8 randomly chosen pairings of independent male and female rat liver cDNA samples and 8 randomly chosen pairings of independent male and continuous GH-treated male rat liver cDNA samples, totaling 16 samples. Half of the samples were hybridized to the MWG Rat 5K microarrays and the other half were hybridized to the MWG Rat Liver microarrays. Comparison of the set of sex-dependent genes with the set of GH-responsive genes shows that 90% of male-dominant genes are suppressed in male rats treated with a female pattern of GH. Approximately 73% of female-dominant genes were up-regulated in the continuous GH-treated male rats. Keywords = Growth hormone Keywords = liver sexual dimorphism Keywords = cytochrome P450 Keywords = liver gene expression Keywords = dual channel cDNA microarray Keywords: repeat sample
Project description:This SuperSeries is composed of the SubSeries listed below. This SuperSeries is part of a study entitled 'Constitutively active STAT5b feminizes mouse liver gene expression', where delivery of constitutively active STAT5 (STAT5CA) to male mouse liver was shown to induce widespread feminization of the liver, with extensive induction of female-biased genes and repression of male-biased genes, largely mimicking results obtained when male mice are given GH as a continuous infusion. Many of the STAT5CA-responding genes were associated with nearby (< 50 kb) sites of STAT5 binding to liver chromatin, supporting the proposed direct role of persistently active STAT5 in continuous GH-induced liver feminization. The feminizing effects of STAT5CA were dose-dependent; moreover, at higher levels, STAT5CA overexpression resulted in some histopathology, including hepatocyte hyperplasia, and increased karyomegaly and multinuclear hepatocytes. Together, these findings establish that the persistent activation of STAT5 by GH that characterizes female liver is by itself sufficient to account for the sex-dependent expression of a majority of hepatic sex-biased genes.
Project description:PolyA-selected total RNA isolated from livers of adult male mice administered AAV8-STAT5ca was analyzed by RNA-seq to determine the impact of constitutive STAT5 activation on the expression of sex-biased genes in male mouse liver. This is part of a study entitled 'Constitutively active STAT5b feminizes mouse liver gene expression', where delivery of constitutively active STAT5 (STAT5CA) to male mouse liver was shown to induce widespread feminization of the liver, with extensive induction of female-biased genes and repression of male-biased genes, largely mimicking results obtained when male mice are given GH as a continuous infusion. Many of the STAT5CA-responding genes were associated with nearby (< 50 kb) sites of STAT5 binding to liver chromatin, supporting the proposed direct role of persistently active STAT5 in continuous GH-induced liver feminization. The feminizing effects of STAT5CA were dose-dependent; moreover, at higher levels, STAT5CA overexpression resulted in some histopathology, including hepatocyte hyperplasia, and increased karyomegaly and multinuclear hepatocytes. Together, these findings establish that the persistent activation of STAT5 by GH that characterizes female liver is by itself sufficient to account for the sex-dependent expression of a majority of hepatic sex-biased genes.
Project description:PolyA-selected nuclear RNA isolated from livers of adult male mice administered AAV8-STAT5ca was analyzed by RNA-seq to determine the impact of constitutive STAT5 activation on the expression of sex-biased genes in male mouse liver. This is part of a study entitled 'Constitutively active STAT5b feminizes mouse liver gene expression', where delivery of constitutively active STAT5 (STAT5CA) to male mouse liver was shown to induce widespread feminization of the liver, with extensive induction of female-biased genes and repression of male-biased genes, largely mimicking results obtained when male mice are given GH as a continuous infusion. Many of the STAT5CA-responding genes were associated with nearby (< 50 kb) sites of STAT5 binding to liver chromatin, supporting the proposed direct role of persistently active STAT5 in continuous GH-induced liver feminization. The feminizing effects of STAT5CA were dose-dependent; moreover, at higher levels, STAT5CA overexpression resulted in some histopathology, including hepatocyte hyperplasia, and increased karyomegaly and multinuclear hepatocytes. Together, these findings establish that the persistent activation of STAT5 by GH that characterizes female liver is by itself sufficient to account for the sex-dependent expression of a majority of hepatic sex-biased genes.
Project description:Sex differences in liver gene expression are dictated by sex-differences in circulating growth hormone (GH) profiles. Presently, the pituitary hormone dependence of mouse liver gene expression was investigated on a global scale to discover sex-specific early GH response genes that might contribute to sex-specific regulation of downstream GH targets and to ascertain whether intrinsic sex-differences characterize hepatic responses to plasma GH stimulation. RNA expression analysis using 41,000-feature microarrays revealed two distinct classes of sex-specific mouse liver genes: genes subject to positive regulation (class-I) and genes subject to negative regulation by pituitary hormones (class-II). Genes activated or repressed in hypophysectomized (Hypox) mouse liver within 30-90min of GH pulse treatment at a physiological dose were identified as direct targets of GH action (early response genes). Intrinsic sex-differences in the GH responsiveness of a subset of these early response genes were observed. Notably, 45 male-specific genes, including five encoding transcriptional regulators that may mediate downstream sex-specific transcriptional responses, were rapidly induced by GH (within 30min) in Hypox male but not Hypox female mouse liver. The early GH response genes were enriched in 29 male-specific targets of the transcription factor Mef2, whose activation in hepatic stellate cells is associated with liver fibrosis leading to hepatocellular carcinoma, a male-predominant disease. Thus, the rapid activation by GH pulses of certain sex-specific genes is modulated by intrinsic sex-specific factors, which may be associated with prior hormone exposure (epigenetic mechanisms) or genetic factors that are pituitary-independent, and could contribute to sex-differences in predisposition to liver cancer or other hepatic pathophysiologies.
Project description:Sex-dependent pituitary growth hormone (GH) secretory patterns determine the sex-biased expression of >1,000 genes in mouse and rat liver, affecting lipid and drug metabolism, inflammation and disease. A fundamental biological question is how robust differential expression can be achieved for hundreds of sex-biased genes simply based on the GH input signal pattern: pulsatile GH stimulation in males vs. near-continuous GH exposure in females. STAT5 is an essential transcriptional mediator of the sex-dependent effects of GH in the liver, but the mechanisms that underlie its sex-dependent actions are obscure. Here we elucidate the dynamic, sex-dependent binding of STAT5 and the GH/STAT5-regulated repressor BCL6 to mouse liver chromatin, revealing the counteractive interplay between these two regulators of liver sex-specificity. Our findings establish a close correlation between sex-dependent STAT5 binding and sex-biased target gene expression. Moreover, sex-dependent STAT5 binding correlated positively with sex-biased DNase hypersensitivity and H3-K4me1 and H3-K4me3 (activating) marks, correlated negatively with sex-biased H3-K27me3 (repressive) marks, and was associated with sex-differentially enriched motifs for HNF6/CDP factors. Importantly, BCL6 binding was preferentially associated with repression of female-biased STAT5 targets in male liver. Furthermore, BCL6 and STAT5 common targets but not BCL6 unique targets showed strong enrichment for lipid and drug metabolism. These findings provide a comprehensive, genome-wide view of the mechanisms whereby these two GH-regulated transcription factors establish and maintain sex differences affecting liver physiology and disease. The approaches used here to characterize sex-dependent STAT5 and BCL6 binding can be applied to other condition-specific regulatory factors and binding sites and their interplay with co-operative chromatin-binding factors. Mouse livers were excised from individual male and female mice killed at either a peak of STAT5 binding activity, or during the growth hormone (GH) interpulse interval, when STAT5 activity is either low (females) or essentially undetectable (males). Sonicated, cross-linked liver nuclear chromatin was then used to identify STAT5 binding sites by ChIP-Seq.