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.
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:The goal of this study is to check if elevated level of IL-23 and/or its downstream cytokines affect the gene expression in the jejunum of newborn mice. We engineered a mice strain in which the expression of IL-23 was directed to the keratinocytes (KSR23). The KSR23 mice had normal body weight at birth and much smaller than their control littermates at day 5. KSR23 mice died prematurely (before 15 days of age), but displayed no signs of disease in the skin, intestine, or in other organs examined. To investigate if elevated level of IL-23 and/or its downstreamcytokines could affect body growth, we examined the transcriptome of the the intestine, which are critical for the processing and absorption of nutrients. Jejunum mRNA profiles of 5-day-old WT and KSR23 were generated by deep sequencing. The transcriptome of the Jejunum of KSR23 mice at P5 differed significantly from that of their control littermates (WT). Several genes were differentially expressed, including IL-22, and genes that are downstream of it such as Reg3 genes and digestive enzymes also produced by the jejunum. Kegg pathway analysis of WT and KSR23 jejunum indicated that genes involved in protein digestion and absorption such as chymotrypsinogen B1 (Ctrb1), trypsinogen (Prss1), trypsin (Tyr5 and Tyr4), caboxypeptidase a1 (Cpa1) and chymotrypsin-like elastase family member 3b (Cela3b), were downregulated in the intestine of KSR23 mice. Transcriptome analysis also showed decreased expression of several genes involved in the regulation of the very low-density lipoprotein particle pathway (VLDL). These particles regulate fat and cholesterol release into the bloodstream. Together, these results indicate that systemic expression of IL-23, and other cytokines, correlated with significant transcriptional changes in genes that regulate food processing in the intestine.
Project description:Analysis of changes in gene expression following hepatocyte specific deletion of GATA4 in adult mice. Results showed that the subset of differentially expressed genes had liver specific ontologies. Total RNA isolated from hepatocytes of AAV8-Tbg-Cre injected GATA4 fl/fl mice was compared to total RNA isolated from AAV-Tbg-GFP injected GATA4 fl/fl mice.
Project description:GATA4 regulates the liver development, but it's function and the gene transcriptional programs it regulates in the adult liver is unknown. In this study, we determined the genome-wide occupancy sites of GATA4 by performing ChIP-seq of whole livers. We have identified 4409 GATA4 enrichment peaks using two peak calling methods and irreproducible discovery rate (IDR) analysis. This corresponds to 3075 genes with GATA4 peaks within -5 kb of transcription start site (TSS) and +5 kb of transcription termination site (TTS). MEME analysis shows that approximately 90% of the peaks have the WGATAR motif, suggesting direct binding by GATA4. The peaks containing the WGATAR motif have a ChIP-seq higher tag enrichment score than peaks lacking the motif. Genome Regions Enrichment of Annotations Tool (GREAT) analysis of genes bound by GATA4 identified ontologies with liver specific functions. In summary, our study shows for the first time genome-wide occupancy profile of GATA4in the adult mouse liver. ChIP-sequencing of whole mouse livers from 2-3 month old mice
Project description:Using mice deficient in hepatic cytochrome-P450 oxidoreductase (POR), which disables the liver cytochrome P450 system, the metabolism and biological response of the anti-carcinogenic flavonoid, quercetin, was examined. Profiling circulating metabolites revealed similar profiles over 72 h in wild type (WT) and POR-null (KO) mice, showing that hepatic P450 and reduced biliary secretion do not affect quercetin metabolism. Transcriptional profiling at 24 h revealed that 2-3 fold more genes responded significantly to quercetin in WT compared to KO in the jejunum, ileum, colon, and liver, suggesting that hepatic P450s mediate many of the biological effects of quercetin, such as immune function, estrogen receptor signaling and lipid, glutathione, purine, and amino acid metabolism, even though quercetin metabolism is not modified. The functional interpretation of expression data in response to quercetin (single dose of 7 mg/animal) revealed a molecular relationship between the liver and jejunum. In WT animals, amino acid and sterol metabolism were predominantly modulated in the liver, fatty acid metabolism response was shared between the liver and jejunum, and glutathione metabolism was modulated in the small intestine. In contrast, KO animals do not regulate amino acid metabolism in the liver or small intestine, they share the control of fatty acid metabolism between the liver and jejunum, and regulation of sterol metabolism is shifted from the liver to the jejunum and that of glutathione metabolism from the jejunum to the liver. This demonstrates that the quercetin-mediated regulation of these biological functions in extrahepatic tissues is dependent on the functionality of the liver POR. In conclusion, using a systems biology approach to explore the contribution of hepatic phase I detoxification on quercetin metabolism demonstrated the resiliency and adaptive capacity of a biological organism in dealing with a bioactive nutrient when faced with a tissue-specific molecular dysfunction. Keywords: nutritional intervention, comparative genomic response, genotype variation
Project description:We investigated the effect of feeding mice a Total Western Diet formulated using the 50th percentile daily intake levels for macro and micronutrients from the National Health and Nutrition Examination Survey (NHANES) with 0, 2, 5, or 10% added raw potato starch on the cecal microbiome (16S) and cecum, proximal and distal colon gene expression by RNASeq analysis.
Project description:We have demonstrated previously that mammalian sexual differentiation requires both GATA4 and FOG2 transcription regulators to assemble the functioning testis. We have now determined that the sexual development of female mice is profoundly affected by the loss of GATA4-FOG2 interaction. We have also identified the Dkk1 gene, encoding a secreted inhibitor of canonical β-catenin signaling as a target of GATA4/FOG2 repression in the developing ovary. The tissue-specific ablation of the β-catenin gene in the gonads disrupts female development while in the Gata4ki/ki/Dkk1-/- or Fog2-/-/Dkk1-/- embryos the normal ovarian gene expression pattern is partially restored. Control of ovarian development by the GATA4/FOG2 complex presents a novel insight into the crosstalk of transcriptional regulation and extracellular signaling in ovarian development. Keywords: genetic modification