Project description:GATA4 is expressed in the proximal 85% of small intestine where it promotes a proximal intestinal ('jejunal') identity while repressing a distal intestinal ('ileal') identity, but its molecular mechanisms are unclear. Here, we tested the hypothesis that GATA4 promotes a jejunal versus ileal identity in mouse intestine by directly activating and repressing specific subsets of absorptive enterocyte genes by modulating the acetylation of histone H3, lysine 27 (H3K27), a mark of active chromatin, at sites of GATA4 occupancy. Global analysis of mouse jejunal epithelium showed a statistically significant association of GATA4 occupancy with GATA4-regulated genes. Occupancy was equally distributed between down- and up-regulated targets, and occupancy sites showed a dichotomy of unique motif over-representation at down- versus up-regulated genes. H3K27ac enrichment at GATA4-binding loci that mapped to down-regulated genes (activation targets) was elevated, changed little upon conditional Gata4 deletion, and was similar to control ileum, whereas H3K27ac enrichment at GATA4-binding loci that mapped to up-regulated genes (repression targets) was depleted, increased upon conditional Gata4 deletion, and approached H3K27ac enrichment in wild-type control ileum. These data support the hypothesis that GATA4 both activates and represses intestinal genes, and show that GATA4 represses an ileal program of gene expression in the proximal small intestine by inhibiting the acetylation of H3K27. 2 samples were analyzed (1 ChIPseq, 1 input sample), control was done by confirming ChIP-qPCR on specific targets
Project description:To assess the role of LSD1 in mouse small intestinal epithelium, we grew small intestinal organoids in vitro from mice with an epithelial specific deletion of LSD1 (Villin-Cre+; Lsd1f/f) and from wild type (Villin-Cre-; Lsd1f/f) mice. This experiment uses a new Cre strain with 100% recombination efficiency. Similar to intestinal epithelium from mice with an intestinal epithelium specific LSD1-KO, Paneth cells are not present in LSD1-KO small intestinal organoids. We used these sequencing data to show intrinsic epithelial changes in the intestinal epithelium caused by LSD1 deletion in the absence of microbiota and surrounding in vivo cell types.
Project description:GATA4 is expressed in the proximal 85% of small intestine where it promotes a proximal intestinal ('jejunal') identity while repressing a distal intestinal ('ileal') identity, but its molecular mechanisms are unclear. Here, we tested the hypothesis that GATA4 promotes a jejunal versus ileal identity in mouse intestine by directly activating and repressing specific subsets of absorptive enterocyte genes by modulating the acetylation of histone H3, lysine 27 (H3K27), a mark of active chromatin, at sites of GATA4 occupancy. Global analysis of mouse jejunal epithelium showed a statistically significant association of GATA4 occupancy with GATA4-regulated genes. Occupancy was equally distributed between down- and up-regulated targets, and occupancy sites showed a dichotomy of unique motif over-representation at down- versus up-regulated genes. H3K27ac enrichment at GATA4-binding loci that mapped to down-regulated genes (activation targets) was elevated, changed little upon conditional Gata4 deletion, and was similar to control ileum, whereas H3K27ac enrichment at GATA4-binding loci that mapped to up-regulated genes (repression targets) was depleted, increased upon conditional Gata4 deletion, and approached H3K27ac enrichment in wild-type control ileum. These data support the hypothesis that GATA4 both activates and represses intestinal genes, and show that GATA4 represses an ileal program of gene expression in the proximal small intestine by inhibiting the acetylation of H3K27.
Project description:Cardiac hypertrophy is regulated by the zinc finger-containing DNA binding factors Gata4 and Gata6, both of which are required to mount a productive growth response of the adult heart. To determine if Gata4 and Gata6 are redundant or have non-overlapping roles, we performed cardiomyocyte-specific conditional gene deletions for Gata4 and Gata6 in conjunction with reciprocal replacement with a transgene encoding either Gata4 or Gata6, during the pressure overload response. We determined that Gata4 and Gata6 play a redundant and dosage-sensitive role in programming the hypertrophic growth response itself following pressure overload stimulation. However, non-redundant functions were identified as functional decompensation induced by either Gata4 or Gata6 deletion was not rescued by the reciprocal transgene, and only Gata4 heart-specific deletion produced a reduction in capillary density after pressure overload. Gene expression profiling from hearts of these gene-deleted mice showed both overlapping and unique transcriptional codes, with Gata4 exhibiting the strongest impact. These results indicate that Gata4 and Gata6 play a dosage-dependent and semi-redundant role in programming cardiac hypertrophy, but that each has a unique role in maintaining cardiac homeostasis and adaptation to injury that cannot be compensated by the other. Microarray-bassed gene expression profiling identified overlapping, distinct, and quantitatively/differentially regulated classes of Gata4 or Gata6 regulated genes. To determine if Gata4 and Gata6 are redundant or have non-overlapping roles in programming cardiac hypertrophic responses and adaptation to stress or injury, we performed cardiomyocyte-specific conditional gene deletions for Gata4 and Gata6 in conjunction with reciprocal replacement with a transgene encoding either Gata4 or Gata6, during the pressure overload response.
Project description:Differentiation and specialisation of epithelial cells in the small intestine is regulated in two ways. First, there is differentiation along the crypt-villus axis of the intestinal stem cells into absorptive enterocytes, Paneth, goblet, tuft, enteroendocrine or M-cells, which is mainly regulated by WNT. Second, there is specialization along the cephalocaudal axis with different absorptive and digestive functions in duodenum, jejunum and ileum that is controlled by several transcription factors such as GATA4. However, so far it is unknown whether location-specific functional properties are intrinsically programmed within stem cells or if continuous signalling from mesenchymal cells is necessary to maintain the location-specific identity of the small intestine. By using the pure epithelial organoid technique, we show that region-specific gene expression profiles are conserved throughout long-term cultures of both mouse and human intestinal stem cells and correlated with differential Gata4 expression. Furthermore, the human organoid culture system demonstrates that Gata4-regulated gene expression is only allowed in absence of WNT signalling. These data show that location-specific function is intrinsically programmed in the adult stem cells of the small intestine and that their differentiation fate is independent of location-specific extracellular signals. In light of the potential future clinical application of small intestine-derived organoids, our data imply that it is important to generate GATA4-positive and GATA4-negative cultures to regenerate all essential functions of the small intestine. RNA sequencing of intestinal crypts, villi and cultured organoids derived from mouse duodenum, jejunum and ileum
Project description:To assess the role of LSD1 in mouse small intestinal epithelium, we isolated small intestinal crypts and villus from wild type (WT) (Villin-Cre -; Lsd1f/f) and intestinal-epithelial-specific knock-out (cKO) (Villin-Cre+; Lsd1f/f) mice. This experiment uses a new Cre strain with 100% deletion efficiency. RNA was directly isolated from intestinal crypt and villus, and this was used for RNAseq. Gene expression analysis of cKO derived crypt and villus provides a spatially restricted outlook on the maturation status of the intestinal epithelium in the villi and the absence of Paneth cells in the crypt.
Project description:Cardiac hypertrophy is regulated by the zinc finger-containing DNA binding factors Gata4 and Gata6, both of which are required to mount a productive growth response of the adult heart. To determine if Gata4 and Gata6 are redundant or have non-overlapping roles, we performed cardiomyocyte-specific conditional gene deletions for Gata4 and Gata6 in conjunction with reciprocal replacement with a transgene encoding either Gata4 or Gata6, during the pressure overload response. We determined that Gata4 and Gata6 play a redundant and dosage-sensitive role in programming the hypertrophic growth response itself following pressure overload stimulation. However, non-redundant functions were identified as functional decompensation induced by either Gata4 or Gata6 deletion was not rescued by the reciprocal transgene, and only Gata4 heart-specific deletion produced a reduction in capillary density after pressure overload. Gene expression profiling from hearts of these gene-deleted mice showed both overlapping and unique transcriptional codes, with Gata4 exhibiting the strongest impact. These results indicate that Gata4 and Gata6 play a dosage-dependent and semi-redundant role in programming cardiac hypertrophy, but that each has a unique role in maintaining cardiac homeostasis and adaptation to injury that cannot be compensated by the other. Microarray-bassed gene expression profiling identified overlapping, distinct, and quantitatively/differentially regulated classes of Gata4 or Gata6 regulated genes.
Project description:To study the role of tet3 and 5-hydroxymethylation in mouse intestine homeostasis our objectives are: To determine the cell types that show a 5hmC reduction level in the absence of Tet3. Identify the role of Tet3 on transcriptional regulation in the small intestinal epithelium. Define the physiological functions impaired in Tet3 -/- small intestine epithelium.