Project description:Early postnatal overnutrition causes persistent dysregulation of endocrine pancreas function. We used genome-scale DNA methylation profiling in the suckling-period small litter (SL) mouse model to test whether this occurs via persistent epigenetic changes in pancreatic islets. Although SL islets showed DNA methylation changes directly after weaning and in adulthood, few of these were present at both ages, contrary to our hypothesis. Most interestingly, we discovered that genomic regions that are hypermethylated in exocrine relative to endocrine pancreas tend to gain methylation in islets during aging. Focusing on a subset of genes relevant to β cell function, we showed that these methylation differences are strongly correlated with expression. Together, our results provide the novel insight that DNA methylation changes that occur as islets age indicate an overall epigenetic drift toward the exocrine pancreas epigenome. These concerted shifts in the islet methylome could contribute to the age-associated decline in endocrine pancreas function. Pancreatic islets were isolated from P21/P180 SL or C mice. To ensure purity of islets, 3 rounds of manual picking were performed in each samples. Whole pancreas samples, ~98% of which is exocrine pancreas, were used as exocrine pancreas. There are 5 mice per group.
Project description:Early postnatal overnutrition causes persistent dysregulation of endocrine pancreas function. We used genome-scale DNA methylation profiling in the suckling-period small litter (SL) mouse model to test whether this occurs via persistent epigenetic changes in pancreatic islets. Although SL islets showed DNA methylation changes directly after weaning and in adulthood, few of these were present at both ages, contrary to our hypothesis. Most interestingly, we discovered that genomic regions that are hypermethylated in exocrine relative to endocrine pancreas tend to gain methylation in islets during aging. Focusing on a subset of genes relevant to β cell function, we showed that these methylation differences are strongly correlated with expression. Together, our results provide the novel insight that DNA methylation changes that occur as islets age indicate an overall epigenetic drift toward the exocrine pancreas epigenome. These concerted shifts in the islet methylome could contribute to the age-associated decline in endocrine pancreas function.
Project description:We have determined the cistrome and transcriptome for the nuclear receptor liver receptor homolog-1 (LRH-1) in the exocrine pancreas. Chromatin immunoprecipitation (ChIP)-seq and RNA-seq analyses reveal that LRH-1 directly induces expression of genes encoding digestive enzymes and secretory and mitochrondrial proteins. LRH-1 cooperates with the pancreas transcription factor 1-L complex (PTF1-L) in regulationg exocrine pancreas-specific gene expression. Elimination of LRH-1 in adult mice reduced the concentration of several lipases and proteases in pancreatic fluid and impaired pancreatic fluid secretion in response to cholecystokinin. Thus, LRH-1 is a key regulator of the exocrine pancreas-specific transcriptional network required for the production and secretion of pancreatic fluid. input and Lrh1 ChIP
Project description:We used single-cell RNA-sequencing to generate transcriptional profiles of endocrine and exocrine cell types of the human pancreas. Pancreatic tissue and islets were obtained from six healthy and four T2D cadaveric donors. Islets were cultured and dissociated into single-cell suspension. Viable individual cells were distributed via fluorescence-activated cell sorted (FACS) into 384-well plates containing lysis buffer. Single-cell cDNA libraries were generated using the Smart-seq2 protocol. Gene expression was quantified as reads per kilobase transcript and per million mapped reads (RPKM) using rpkmforgenes. Bioinformatics analysis was used to classify cells into cell types without knowledge of cell types or prior purification of cell populations. We revealed subpopulations in endocrine and exocrine cell types, identified genes with interesting correlations to body mass index (BMI) in specific cell types and found transcriptional alterations in T2D. Complementary whole-islet RNA-seq data have also been deposited at ArrayExpress under accession number E-MTAB-5060 (http://www.ebi.ac.uk/arrayexpress/experiments/E-MTAB-5060).
Project description:We have determined the cistrome and transcriptome for the nuclear receptor liver receptor homolog-1 (LRH-1) in the exocrine pancreas. Chromatin immunoprecipitation (ChIP)-seq and RNA-seq analyses reveal that LRH-1 directly induces expression of genes encoding digestive enzymes and secretory and mitochrondrial proteins. LRH-1 cooperates with the pancreas transcription factor 1-L complex (PTF1-L) in regulationg exocrine pancreas-specific gene expression. Elimination of LRH-1 in adult mice reduced the concentration of several lipases and proteases in pancreatic fluid and impaired pancreatic fluid secretion in response to cholecystokinin. Thus, LRH-1 is a key regulator of the exocrine pancreas-specific transcriptional network required for the production and secretion of pancreatic fluid.
Project description:Several miRNAs have tissue-specific patterns consistent with crucial functions in many biological processes and are candidate biomarkers of disease. Yet, there is limited knowledge about the role of pancreas-specific miRNAs in pancreatic pathologies. Here, we show that miR-216a is a conserved, pancreas-specific miRNA with important roles in pancreatic islet and acinar cells. By profiling miRNAs from human islets and subsequent systematic tissue analysis we found that miR-216a is highly enriched in endocrine and exocrine pancreas. Deletion of miR-216a in mice lead to a reduction in islet size, β-cell mass and insulin levels. RNA-sequencing indicated that cell cycle and proliferation were the most significantly regulated biological processes in miR-216 knockout pancreata. miR-216a was induced by TGF-β signalling and inhibition of miR-216a increased apoptosis and decreased cell proliferation in both β- and exocrine cells. Deletion of miR-216a in the pancreatic cancer prone mouse line Kras G12D ;Ptf1a CreER reduced the propensity of pancreatic cancer precursor lesions. Notably, circulating miR-216a levels were elevated in both mice and humans with pancreatic cancer. Collectively, our study gives insights into how β-cell mass and acinar cell growth are modulated by a pancreas-specific miRNA but also suggests miR-216a as a promising biomarker for diagnosis of pancreatic diseases.
Project description:Several miRNAs have tissue-specific patterns consistent with crucial functions in many biological processes and are candidate biomarkers of disease. Yet, there is limited knowledge about the role of pancreas-specific miRNAs in pancreatic pathologies. Here, we show that miR-216a is a conserved, pancreas-specific miRNA with important roles in pancreatic islet and acinar cells. By profiling miRNAs from human islets and subsequent systematic tissue analysis we found that miR-216a is highly enriched in endocrine and exocrine pancreas. Deletion of miR-216a in mice lead to a reduction in islet size, β-cell mass and insulin levels. RNA-sequencing indicated that cell cycle and proliferation were the most significantly regulated biological processes in miR-216 knockout pancreata. miR-216a was induced by TGF-β signalling and inhibition of miR-216a increased apoptosis and decreased cell proliferation in both β- and exocrine cells. Deletion of miR-216a in the pancreatic cancer prone mouse line Kras G12D ;Ptf1a CreER reduced the propensity of pancreatic cancer precursor lesions. Notably, circulating miR-216a levels were elevated in both mice and humans with pancreatic cancer. Collectively, our study gives insights into how β-cell mass and acinar cell growth are modulated by a pancreas-specific miRNA but also suggests miR-216a as a promising biomarker for diagnosis of pancreatic diseases.
Project description:It is known that the stresses encountered during islet isolation have deleterious effects on beta-cell physiology. The nature of these effects, however, is incompletely known, partly due to the heterogeneity of islet preparations. The objective was to assess the genome-wide effect of islet isolation and in-vitro culture on beta-cell transcriptome. Beta cells identified by their intrinsic autofluorescence, were captured from donor pancreas and isolated islets using Laser Capture Microdissection. Beta cells from donor pancreas serve as the control. Our results indicated induction of a strong inflammatory response induced by islet isolation which continues during in vitro culture manifested by upregulation of several cytokines, chemokines and their receptors. IL-8 was induced by 3.6-fold and 56-fold in fresh and 3-days cultured islets respectively. Concordantly, several pancreatic progenitor cell-specific transcription factors like were upregulated in cultured islets, suggesting progressive transformation of mature beta-cell phenotype toward an immature endocrine cell phenotype. There are three sample types in our experiment; 1) beta-cells captured from the frozen sections of donor pancreas n=8, 2) beta cells extracted from islets frozen immediately after isolation (d0 islets) n=8 and, 3) beta cells extracted from isolated islets frozen after culturing for 3 days (d3 islets) n=5. For the analysis, beta cells from pancreas were considered as the reference point.