Project description:GATA4 is a transcription factor known for its crucial role in the development of many tissues, including liver; however, its role in adult liver metabolism is unknown. Here, using high-throughput sequencing technologies, including assay for transposase-accessible chromatin with sequencing (ATAC-Seq), we identified GATA4 as a transcriptional regulator of metabolism in liver. GATA4 expression is elevated in response to refeeding, and its occupancy is increased at enhancers of genes linked to fatty acid and lipoprotein metabolism. Knocking out GATA4 in adult liver (Gata4LKO) decreased transcriptional activity at GATA4 binding sites especially during feeding. Gata4LKO mice have reduced plasma HDL cholesterol and increased liver triglyceride levels. The expression of a panel of genes involved in cholesterol export and triglyceride hydrolysis was downregulated and the expression of those involved in lipid uptake were upregulated in Gata4LKO liver, We further demonstrate that GATA4 collaborates with LXR liver. GATA4 shares a number of binding sites and direct transcriptional targets with LXRs, and loss of GATA4 impairs the hepatic transcriptional response to LXR agonist. Collectively, these results show that hepatic GATA4 contributes to the transcriptional control of hepatic and systemic lipid homeostasis.
Project description:GATA4 is a transcription factor known for its crucial role in the development of many tissues, including liver; however, its role in adult liver metabolism is unknown. Here, using high-throughput sequencing technologies, including assay for transposase-accessible chromatin with sequencing (ATAC-Seq), we identified GATA4 as a transcriptional regulator of metabolism in liver. GATA4 expression is elevated in response to refeeding, and its occupancy is increased at enhancers of genes linked to fatty acid and lipoprotein metabolism. Knocking out GATA4 in adult liver (Gata4LKO) decreased transcriptional activity at GATA4 binding sites especially during feeding. Gata4LKO mice have reduced plasma HDL cholesterol and increased liver triglyceride levels. The expression of a panel of genes involved in cholesterol export and triglyceride hydrolysis was downregulated and the expression of those involved in lipid uptake were upregulated in Gata4LKO liver, We further demonstrate that GATA4 collaborates with LXR liver. GATA4 shares a number of binding sites and direct transcriptional targets with LXRs, and loss of GATA4 impairs the hepatic transcriptional response to LXR agonist. Collectively, these results show that hepatic GATA4 contributes to the transcriptional control of hepatic and systemic lipid homeostasis.
Project description:GATA4 is a transcription factor known for its crucial role in the development of many tissues, including liver; however, its role in adult liver metabolism is unknown. Here, using high-throughput sequencing technologies, including assay for transposase-accessible chromatin with sequencing (ATAC-Seq), we identified GATA4 as a transcriptional regulator of metabolism in liver. GATA4 expression is elevated in response to refeeding, and its occupancy is increased at enhancers of genes linked to fatty acid and lipoprotein metabolism. Knocking out GATA4 in adult liver (Gata4LKO) decreased transcriptional activity at GATA4 binding sites especially during feeding. Gata4LKO mice have reduced plasma HDL cholesterol and increased liver triglyceride levels. The expression of a panel of genes involved in cholesterol export and triglyceride hydrolysis was downregulated and the expression of those involved in lipid uptake were upregulated in Gata4LKO liver, We further demonstrate that GATA4 collaborates with LXR liver. GATA4 shares a number of binding sites and direct transcriptional targets with LXRs, and loss of GATA4 impairs the hepatic transcriptional response to LXR agonist. Collectively, these results show that hepatic GATA4 contributes to the transcriptional control of hepatic and systemic lipid homeostasis.
Project description:GATA4 is a transcription factor known for its crucial role in the development of many tissues, including liver; however, its role in adult liver metabolism is unknown. Here, using high-throughput sequencing technologies, including assay for transposase-accessible chromatin with sequencing (ATAC-Seq), we identified GATA4 as a transcriptional regulator of metabolism in liver. GATA4 expression is elevated in response to refeeding, and its occupancy is increased at enhancers of genes linked to fatty acid and lipoprotein metabolism. Knocking out GATA4 in adult liver (Gata4LKO) decreased transcriptional activity at GATA4 binding sites especially during feeding. Gata4LKO mice have reduced plasma HDL cholesterol and increased liver triglyceride levels. The expression of a panel of genes involved in cholesterol export and triglyceride hydrolysis was downregulated and the expression of those involved in lipid uptake were upregulated in Gata4LKO liver, We further demonstrate that GATA4 collaborates with LXR liver. GATA4 shares a number of binding sites and direct transcriptional targets with LXRs, and loss of GATA4 impairs the hepatic transcriptional response to LXR agonist. Collectively, these results show that hepatic GATA4 contributes to the transcriptional control of hepatic and systemic lipid homeostasis.
Project description:GATA4 is a transcription factor known for its crucial role in the development of many tissues, including liver; however, its role in adult liver metabolism is unknown. Here, using high-throughput sequencing technologies, including assay for transposase-accessible chromatin with sequencing (ATAC-Seq), we identified GATA4 as a transcriptional regulator of metabolism in liver. GATA4 expression is elevated in response to refeeding, and its occupancy is increased at enhancers of genes linked to fatty acid and lipoprotein metabolism. Knocking out GATA4 in adult liver (Gata4LKO) decreased transcriptional activity at GATA4 binding sites especially during feeding. Gata4LKO mice have reduced plasma HDL cholesterol and increased liver triglyceride levels. The expression of a panel of genes involved in cholesterol export and triglyceride hydrolysis was downregulated and the expression of those involved in lipid uptake were upregulated in Gata4LKO liver, We further demonstrate that GATA4 collaborates with LXR liver. GATA4 shares a number of binding sites and direct transcriptional targets with LXRs, and loss of GATA4 impairs the hepatic transcriptional response to LXR agonist. Collectively, these results show that hepatic GATA4 contributes to the transcriptional control of hepatic and systemic lipid homeostasis.
Project description:GATA4 is a transcription factor known for its crucial role in the development of many tissues, including liver; however, its role in adult liver metabolism is unknown. Here, using high-throughput sequencing technologies, including assay for transposase-accessible chromatin with sequencing (ATAC-Seq), we identified GATA4 as a transcriptional regulator of metabolism in liver. GATA4 expression is elevated in response to refeeding, and its occupancy is increased at enhancers of genes linked to fatty acid and lipoprotein metabolism. Knocking out GATA4 in adult liver (Gata4LKO) decreased transcriptional activity at GATA4 binding sites especially during feeding. Gata4LKO mice have reduced plasma HDL cholesterol and increased liver triglyceride levels. The expression of a panel of genes involved in cholesterol export and triglyceride hydrolysis was downregulated and the expression of those involved in lipid uptake were upregulated in Gata4LKO liver, We further demonstrate that GATA4 collaborates with LXR liver. GATA4 shares a number of binding sites and direct transcriptional targets with LXRs, and loss of GATA4 impairs the hepatic transcriptional response to LXR agonist. Collectively, these results show that hepatic GATA4 contributes to the transcriptional control of hepatic and systemic lipid homeostasis.
Project description:GATA4 is a transcription factor known for its crucial role in the development of many tissues, including liver; however, its role in adult liver metabolism is unknown. Here, using high-throughput sequencing technologies, including assay for transposase-accessible chromatin with sequencing (ATAC-Seq), we identified GATA4 as a transcriptional regulator of metabolism in liver. GATA4 expression is elevated in response to refeeding, and its occupancy is increased at enhancers of genes linked to fatty acid and lipoprotein metabolism. Knocking out GATA4 in adult liver (Gata4LKO) decreased transcriptional activity at GATA4 binding sites especially during feeding. Gata4LKO mice have reduced plasma HDL cholesterol and increased liver triglyceride levels. The expression of a panel of genes involved in cholesterol export and triglyceride hydrolysis was downregulated and the expression of those involved in lipid uptake were upregulated in Gata4LKO liver, We further demonstrate that GATA4 collaborates with LXR liver. GATA4 shares a number of binding sites and direct transcriptional targets with LXRs, and loss of GATA4 impairs the hepatic transcriptional response to LXR agonist. Collectively, these results show that hepatic GATA4 contributes to the transcriptional control of hepatic and systemic lipid homeostasis.
Project description:Background and Aims: Although the zinc finger transcription factor GATA4 has been implicated in regulating jejunal gene expression, the contribution of GATA4 in controlling jejunal physiology has not been addressed. Methods: We generated mice in which the Gata4 gene was specifically deleted in the small intestinal epithelium. Measurements of plasma cholesterol and phospholipids, intestinal absorption of dietary fat and cholesterol, and gene expression were performed on these animals. Results: Mice lacking GATA4 in the intestine displayed a dramatic block in their ability to absorb cholesterol and dietary fat. Comparison of the global gene expression profiles of control jejunum, control ileum, and GATA4 null jejunum by gene array analysis demonstrated that GATA4 null jejunum lost expression of 53% of the jejunal-specific gene set and gained expression of 47% of the set of genes unique to the ileum. These alterations in gene expression included a decrease in mRNAs encoding lipid and cholesterol transporters as well as an increase in mRNAs encoding proteins involved in bile acid absorption. Conclusion: Our data demonstrate that GATA4 is essential for jejunal function including fat and cholesterol absorption and confirm that GATA4 plays a pivotal role in determining jejunal versus ileal identity. Keywords: genetic modification
Project description:Metabolic-associated steatohepatitis is a progressive fatty liver disease caused, in part, by hepatocyte stress linked to cholesterol overload. Counteracting this stress may be beneficial but there is insufficient understanding of underlying stress defenses to develop a therapeutic strategy. Here, we aimed to elucidate how stress-adaptive transcription factors, nuclear factor erythroid 2 related factor-1 (NRF1) and -2 (NRF2), counteract hepatic cholesterol overload and determine whether they function cooperatively. C57bl/6 mice were fed high fat, fructose, and cholesterol diet (HFFC). Expression profiling and phenotypic analyses were done on liver of mice with adult-onset and hepatocyte-specific deficiency of NRF1, NRF2, or both, and results compared to control. Chromatin immunoprecipitation (ChIP) sequencing was done and combined with expression profiles to identify genes that NRF1 and NRF2 interact with and regulate in vivo. Three weeks HFFC diet feeding to mice with NRF1 and NRF2 deficiency caused severe steatohepatitis and increased hepatic cholesterol storage. These outcomes did not occur in single gene-deficient mice or control. Expression profiling at a time preceding hepatic cholesterol overload and ChIP sequencing profiling revealed complementary gene regulation by NRF1 and NRF2 to promote cholesterol excretion and mitigate hazardous metabolic biproducts generated from converting cholesterol to bile acid. Consequently, combined gene deficiency, and not single-gene deficiency, increased liver oxidized protein level, decreased cholesterol in bile, and increased unconjugated bile acid in liver and bile. We discover, for the first time, that NRF1 and NRF2 work together to protect liver against damaging effects of excess cholesterol. Targeting these combined actions may prove an effective therapeutic strategy
Project description:Background and Aims: Although the zinc finger transcription factor GATA4 has been implicated in regulating jejunal gene expression, the contribution of GATA4 in controlling jejunal physiology has not been addressed. Methods: We generated mice in which the Gata4 gene was specifically deleted in the small intestinal epithelium. Measurements of plasma cholesterol and phospholipids, intestinal absorption of dietary fat and cholesterol, and gene expression were performed on these animals. Results: Mice lacking GATA4 in the intestine displayed a dramatic block in their ability to absorb cholesterol and dietary fat. Comparison of the global gene expression profiles of control jejunum, control ileum, and GATA4 null jejunum by gene array analysis demonstrated that GATA4 null jejunum lost expression of 53% of the jejunal-specific gene set and gained expression of 47% of the set of genes unique to the ileum. These alterations in gene expression included a decrease in mRNAs encoding lipid and cholesterol transporters as well as an increase in mRNAs encoding proteins involved in bile acid absorption. Conclusion: Our data demonstrate that GATA4 is essential for jejunal function including fat and cholesterol absorption and confirm that GATA4 plays a pivotal role in determining jejunal versus ileal identity. Experiment Overall Design: Total RNA was harvested from the following sources and used to Affymetrix array analysis following manufacturer defined protocols: Experiment Overall Design: control jejunum (Gata4loxP/+VilCre), 3 male mice, adult (6-8 wk) Experiment Overall Design: mutant jejunum (Gata4loxP/-VilCre), 3 male mice, adult (6-8 wk) Experiment Overall Design: control ileum (Gata4loxP/+VilCre), 3 male mice, adult (6-8 wk). Experiment Overall Design: A total of nine Mouse Genome 430_2.0 arrays were hybridized for this study. Experiment Overall Design: Jejunum was defined as 10 cm from the pyloric sphincter, and ileum was defined as 1 cm from the cecum. The animals used to harvest control jejunum and ileum were independent of each other.