We report that Dnmt1 is crucial during perinatal intestinal development. Loss of Dnmt1 in intervillus progenitor cells causes global hypomethylation, DNA damage, premature differentiation, and apoptosis, and consequently, loss of nascent villi. We further confirm the critical role for Dnmt1 during crypt development using the in vitro organoid culture system, and illustrate a clear differential requirement for Dnmt1 in immature versus mature organoids. These results demonstrate an essential role for Dnmt1 in maintaining genomic stability during intestinal development and the establishment of intestinal crypts. Overall design: We performed RNA-Seq of control and Dnmt1-ablated intestinal progenitor cells isolated from parrafin embedded tissues by laser capture microdissection (LCM).
Dnmt1 is essential to maintain progenitors in the perinatal intestinal epithelium.
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View SamplesBackground and Aims: HNF4a is a nuclear hormone receptor transcription factor that has been shown to be required for hepatocyte differentiation and development of the liver. It has also been implicated in regulating expression of genes that act in the epithelium of the lower gastrointestinal tract. This implied that HNF4a might be required for development of the gut. Methods: We generated mouse embryos in which HNF4a was ablated in the epithelial cells of the fetal colon using Cre-loxP technology. Embryos were examined using a combination of histology, immunohistochemistry, gene array and RT-PCR, and chromatin immunoprecipitation analyses to define the consequence of loss of HNF4a on colon development. Results: Embryos could be generated until E18.5 that lacked HNF4a in their colon. Although, early stages of colonic development occurred, HNF4a null colons failed to form normal crypts. In addition, goblet cell maturation was perturbed and expression of an array of genes that encode proteins with diverse roles in colon function was disrupted. Several genes whose expression in the colon was dependent on HNF4a contained HNF4abinding sites sequences within putative transcriptional regulatory regions and a subset of these sites were occupied by HNF4a in vivo. Conclusion: HNF4a is a transcription factor that is essential for development of the mammalian colon, regulates goblet cell maturation and is required for expression of genes that control normal colon function and epithelial cell differentiation.
Hepatocyte nuclear factor 4alpha is essential for embryonic development of the mouse colon.
Specimen part
View SamplesMicroRNAs fine-tune the activity of hundreds of protein-coding genes. The identification of tissue-specific microRNAs and their promoters has been constrained by the limited sensitivity of prior microRNA quantification methods. Here we determine the entire microRNAome of three endoderm-derived tissues, liver, small intestine, and pancreas, using ultra-high throughput sequencing. Although many microRNA genes are expressed at comparable levels, 162 microRNAs exhibited striking tissue-specificity. After mapping the promoters for these microRNA genes using H3K4me3 histone occupancy, we analyzed the regulatory modules of 63 microRNAs differentially expressed between liver and small intestine or pancreas. We determined that the same transcriptional regulatory mechanisms govern tissue-specific gene expression of both mRNA and microRNA encoding genes in mammals.
Tissue-specific regulation of mouse microRNA genes in endoderm-derived tissues.
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View SamplesWe successfully sequenced and annotated more than 400 cells from child, adult control, type 1 diabetes and type 2 diabetes donors. We detect donor-type specific transcript variation. We also report that cells from child donors have less defined gene signature. Cells from type 2 diabetes donors resemble juvenile cells in gene expression. Overall design: Cells from three adult controls (56, 74, 92), one donor with type 1 diabetes (91), two donors with type 2 diabetes (75, 143), and two child donors (40, 72) were sequenced. Numbers in parathesis indicates number of cells sequenced.
Single-Cell Transcriptomics of the Human Endocrine Pancreas.
Specimen part, Subject
View SamplesThe mammalian liver, the largest solid organ in the body, accomplishes multiple critical roles necessary to preserve homeostasis. Human liver diseases are debilitating, costly and very often result in death. Uncovering developmental mechanisms that establish the complex architecture of the liver or generate the cellular diversity of this organ is necessary to develop more adequate methods to prevent, diagnose and cure liver diseases. This study investigated the role of the homeobox gene Prox1 during mouse hepatogenesis.
Prox1 ablation in hepatic progenitors causes defective hepatocyte specification and increases biliary cell commitment.
Specimen part
View SamplesAging at the cellular level is driven by changes in gene activity and epigenetic state that are only partially understood. We performed a comprehensive epigenomic analysis of the pancreatic ß cell, key player in glucose homeostasis and diabetes, in adolescent and very old mice. Globally, we observe a general methylation drift resulting in an overall more leveled methylome, suggesting that the maintenance of highly differential methylation patterns becomes compromised with advanced age. Importantly, we discover targeted changes in the methylation status of ß cell proliferation and function genes that go against the global methylation drift, are specific to ß cells, and correlate with repression of the proliferation program and activation of metabolic regulators. These targeted alterations frequently occur at distal cis-regulator elements, and are associated with specific chromatin marks and transcription factor occupancy in young ß cells. Strikingly, we find the insulin secretory response to glucose much improved in mature ß cells in mice, as predicted by the changes in methylome and transcriptome and in contrast to the decline in function observed in aged human ß cells. Thus, aging of terminally differentiated cells in mammals is not always coupled to functional decline. Overall design: RNA-seq was done on 3 biological replicas from old and three from young beta cells. each sample originated from a pool of 5-10 mic.e H3K27me3 ChIP-seq was done with two replicas for old mice (pool of 4-7 mice) and the rest of the ChIPseq (H3K4me1, H3K27ac and young H3K27me3) was sone with one sample (pool of few mice). BIS-seq was done on one sample from a pool of 10 young mice and one sample of a pool of old mice (18-22 months old)
Aging-Dependent Demethylation of Regulatory Elements Correlates with Chromatin State and Improved β Cell Function.
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View SamplesBackground & Aims: Perturbations in pancreatic ductal bicarbonate secretion often result in chronic pancreatitis. Although the physiological mechanism of ductal secretion is known, its transcriptional control is not well characterized. Here, we investigate the role of the transcription factor Hematopoietically-expressed homeobox protein (Hhex) in pancreatic secretion and pancreatitis. Methods: We derived mice with pancreas-specific, Cre-mediated Hhex gene ablation to determine the requirement of Hhex in the pancreatic duct in early life and in adult stages. Histological and immunostaining analyses were used to detect the presence of pathology. Pancreatic primary ductal cells (PDCs) were isolated to discover differentially expressed transcripts upon acute Hhex ablation. Results: Hhex protein was detected throughout the embryonic and adult ductal trees. Ablation of Hhex in pancreatic progenitors resulted in postnatal ductal ectasia associated with acinar-to-ductal metaplasia, a progressive phenotype that ultimately resulted in chronic pancreatitis. Hhex ablation in adult mice, however, did not cause any detectable pathology. Ductal ectasia did not result from perturbations in primary cilia, but was consistent with the effects of primary ductal hypertension. RNA-seq analysis of Hhex-ablated PDCs indicated the G-protein coupled receptor Natriuretic peptide receptor 3, implicated in paracrine signaling, was upregulated 4.70-fold. Conclusions: Although Hhex is dispensable for adult pancreatic function, ablation of Hhex in pancreatic progenitors results in profound pancreatitis that is consistent with primary ductal hypertension. Our data highlight the critical role of paracrine signaling in maintaining ductal homeostasis, especially in early life, and support ductal hypersecretion as a novel etiology of pediatric chronic pancreatitis. Overall design: Pancreatic primary ductal cells (PDCs) were isolated from uninduced adult HhexL/L;Sox9CreERT2 (n=2) and littermate control HhexL/L (n=2) mice. PDCs were treated with 500nM 4-hydroxytamoxifen in vitro for 4 days, and then RNA was collected for transcriptome analysis.
Spontaneous Pancreatitis Caused by Tissue-Specific Gene Ablation of <i>Hhex</i> in Mice.
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View SamplesProfound changes in cancer cell identity can alter malignant potential and therapeutic response. Loss of the pulmonary lineage specifier NKX2-1 augments the growth of KRAS-driven lung adenocarcinoma and causes pulmonary to gastric transdifferentiation. Here we show that the transcription factors FoxA1 and FoxA2 are required for initiation of mucinous NKX2-1-negative lung adenocarcinomas in the mouse and for activation of their gastric differentiation program. Foxa1/2 deletion severely impairs tumor initiation and causes a proximal shift in cellular identity, yielding tumors expressing markers of the squamocolumnar junction of the gastrointestinal tract. In contrast, stochastic loss of FoxA1/2 expression in NKX2-1-negative tumors is associated with keratinizing squamous differentiation. Using sequential in vivo recombination, we find that FoxA1/2 loss in established KRAS-driven neoplasia is sufficient for direct induction of keratinizing squamous cell carcinomas in the lung. Thus, NKX2-1, FoxA1 and FoxA2 coordinately regulate the growth and identity of lung adenocarcinoma in a context-specific manner. Overall design: Murine lung tumor cells of differing genotypes were isolated by FACS and subjected to single cell analysis using the Fluidigm C1 platform.
FoxA1 and FoxA2 drive gastric differentiation and suppress squamous identity in NKX2-1-negative lung cancer.
Specimen part, Cell line, Subject
View SamplesThe transcriptomes of four subpopulations of beta cells isolated by FACS from five healthy human donors. Populations were defined using cell surface-labeling antibodies, avoiding the need for fixation. Overall design: There are 5 biological replicates of 4 different cell types. Each donor yielded all 4 subtypes.
Human islets contain four distinct subtypes of β cells.
Specimen part, Subject
View SamplesProfound changes in cancer cell identity can alter malignant potential and therapeutic response. Loss of the pulmonary lineage specifier NKX2-1 augments the growth of KRAS-driven lung adenocarcinoma and causes pulmonary to gastric transdifferentiation. Here we show that the transcription factors FoxA1 and FoxA2 are required for initiation of mucinous NKX2-1-negative lung adenocarcinomas in the mouse and for activation of their gastric differentiation program. Foxa1/2 deletion severely impairs tumor initiation and causes a proximal shift in cellular identity, yielding tumors expressing markers of the squamocolumnar junction of the gastrointestinal tract. In contrast, stochastic loss of FoxA1/2 expression in NKX2-1-negative tumors is associated with keratinizing squamous differentiation. Using sequential in vivo recombination, we find that FoxA1/2 loss in established KRAS-driven neoplasia is sufficient for direct induction of keratinizing squamous cell carcinomas in the lung. Thus, NKX2-1, FoxA1 and FoxA2 coordinately regulate the growth and identity of lung adenocarcinoma in a context-specific manner. Overall design: Murine lung tumor cells of differing genotypes were isolated by FACS and subjected to total RNA-Seq.
FoxA1 and FoxA2 drive gastric differentiation and suppress squamous identity in NKX2-1-negative lung cancer.
Specimen part, Cell line, Subject
View Samples