Transcriptome profiling of human pancreatic cell lineage specification reveals functional signaling pathways and lncRNAs for cell fate determination
ABSTRACT: To guide the beta cell differentiation process in vitro, a complete understanding of the transcriptome and their regulatory network during the differentiation process is essential. Using RNA-seq, we have performed the transcriptome profiling of human embryonic stem cells (ESCs), purified ESC-derivate definitive endoderm (DE), pancreatic progenitors (PP), as well as sorted human primary pancreatic alpha cells, beta cells and exocrine cells.
Project description:Insulin-secreting β cells and glucagon-secreting α cells maintain physiological blood glucose levels, and their malfunction drives diabetes development. Using ChIP sequencing and RNA sequencing analysis, we determined the epigenetic and transcriptional landscape of human pancreatic α, β, and exocrine cells. We found that, compared with exocrine and β cells, differentiated α cells exhibited many more genes bivalently marked by the activating H3K4me3 and repressing H3K27me3 histone modifications. This was particularly true for β cell signature genes involved in transcriptional regulation. Remarkably, thousands of these genes were in a monovalent state in β cells, carrying only the activating or repressing mark. Our epigenomic findings suggested that α to β cell reprogramming could be promoted by manipulating the histone methylation signature of human pancreatic islets. Indeed, we show that treatment of cultured pancreatic islets with a histone methyltransferase inhibitor leads to colocalization of both glucagon and insulin and glucagon and insulin promoter factor 1 (PDX1) in human islets and colocalization of both glucagon and insulin in mouse islets. Thus, mammalian pancreatic islet cells display cell-type–specific epigenomic plasticity, suggesting that epigenomic manipulation could provide a path to cell reprogramming and novel cell replacement-based therapies for diabetes. Pancreatic islets were collected post-mortem from 6 human donors and subjected to FACS to separate populations of alpha, beta, and exocrine cells. Depending on the availability of resulting material, sorted islet cell populations were used for H3K4me3, H3K27me3 ChIP-seq, or RNA-seq analysis. All ChIP-seq samples have a corresponding input from the same sample.
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:Type 1 diabetes is an autoimmune disease in which insulin-secreting β cells of the pancreatic islets are selectively destroyed. CD8 T cells are regarded as critical players in mediating β cell destruction and as a result, considerable effort has been expended to define CD8 T cell behaviour in this disease. The overarching aim of the experiment is to characterize a recently identified autoreactive CD57-positive CD8 T cell subset which is associated with loss of function of islet beta cells in type 1 diabetes, to compare the phenotype of the CD57-positive effector memory CD8 T cells versus the CD57-negative compartment, and provide an insight into the function of these cells in the disease process. To that aim, HLA-A*24 positive patients with T1D -within 2 years of diagnosis- were asked to provide a blood, and following consent, and PBMC were isolated. CD57-positive and CD57-negative CD8 T cell populations were sorted by FACS, and finally, RNA was extracted. Amplified cDNA was obtained and used for the library preparation.
Project description:Aims: establishment of reference samples to investigate gene expression selective for endocrine or ductal-exocrine cells within the adult human pancreas. To this end, human islet endocrine cells, FACS-enriched in insulin+ cells, (n=3) and human exocrine ductal cells (n=2) are compared on Affymetrix HG133A platform with duplicate hybridizations of a panel of other primary human tissues. The microarray analysis was performed on 3 pools of human beta cell-enriched cell fractions, isolated from 10 non-selected donor organs, and 2 pools of duct cell-enriched fractions obtained from 6 non-selected donor pancreases. The cells were suspension-cultured for 2-3 weeks along standard procedures and with no specific treatment prior to FACS-sorting and RNA extraction. The average composition of human beta cell-preparations was 55 ± 13% insulin+ cells, 13±8% glucagon+ cells and 21 ±7% non-granulated cells. Pancreatic duct cells-enriched preparations contained 85 ±7% cytokeratin 19+ cells with 4 ± 1% insulin+ cells and 6 ±4% glucagon+ cells and were isolated as described by Heimberg H. et al.( Diabetes 2001,49: 571-579 ). Pancreatic cell mRNA profiles were compared to those of a panel of other human primary tissues (n=2 biological replicates).
Project description:Intensive efforts are focused on identifying regulators of human pancreatic islet cell growth and maturation to accelerate development of therapies for diabetes. After birth, islet cell growth and function are dynamically regulated; however, establishing these age-dependent changes in humans has been challenging. Here we describe a multimodal strategy for isolating pancreatic endocrine and exocrine cells from children and adults to identify age-dependent gene expression and chromatin changes on a genomic scale. These profiles revealed distinct proliferative and functional states of islet alpha-cells or beta-cells, and histone modifications underlying age-dependent gene expression changes. Expression of SIX2 and SIX3, transcription factors without prior known functions in the pancreas and linked to fasting hyperglycemia risk, increased with age specifically in human islet beta-cells. SIX2 and SIX3 were sufficient to enhance insulin content or secretion in immature beta-cells. Our work provides a unique resource to study human-specific regulators of islet cell maturation and function. Overall design: For this study we purified primary human pancreatic cells from juvenile and adult donors and analyzed the chromatin landscape using ChIP-Seq assays.
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:Pancreatitis is more frequent in type 2 diabetes (T2DM) although the underlying cause is unknown. We tested the hypothesis that ongoing beta-cell stress and apoptosis in T2DM induces ductal tree proliferation, particularly the pancreatic duct gland (PDG) compartment, and thus potentially obstructs exocrine outflow. PDG replication was increased two-fold in human pancreas from individuals with T2DM (P<0.01), and was associated with increased pancreatic intraepithelial neoplasia (PanINs) (P<0.05), lesions associated with pancreatic inflammation and with the potential to obstruct pancreatic outflow. Increased PDG replication (p<0.05) in the prediabetic HIP rat model of T2DM was concordant with increased beta-cell stress but preceding metabolic derangement. Moreover, the most abundantly expressed chemokines released by the islets in response to beta-cell stress in T2DM, CXCL1, 4 and 10, induced proliferation in human pancreatic ductal epithelium (p<0.05). Also, the diabetes medications that are reported as potential modifiers for the risk of pancreatitis in T2DM modulated PDG proliferation accordingly. We conclude that chronic stimulation and proliferation of the PDG compartment of the pancreas in response to islet inflammation in T2DM is a novel mechanism that serves as a link to the increased risk for pancreatitis in T2DM and may potentially be modified by currently available diabetes therapy. Overall design: HIP rats vs nondiabetic WT rats ( 4 samples total [2 HIP and 2 WT], so 2 replicates)
Project description:Islet β-cells from newborn mammals need a maturation process to become mature functional beta cells. The detailed molecular mechanisms were not completely understood. This study was designed to reveal the dynamic gene expression changes during pancreatic beta-cell maturation in postnatal mice. We also want to understand how genetic mutations that impair beta-cell function change the genetic networks involved in the beta-cell maturation process. For these aims, pancreatic beta cells were isolated at P1 islets based on the expression of a MipeGFP transgene in a genetic background with pancreatic specific inactivation of Myt1, Myt1L, and St18 (denoted as MytDelpanc; MipeGFP).
Project description:AIMS/HYPOTHESIS: Manoeuvres aimed at increasing beta cell mass have been proposed as regenerative medicine strategies for diabetes treatment. Raf-1 kinase inhibitor protein 1 (RKIP1) is a common regulatory node of the mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) pathways and therefore may be involved in regulation of beta cell homeostasis. The aim of this study was to investigate the involvement of RKIP1 in the control of beta cell mass and function. METHODS: Rkip1 (also known as Pebp1) knockout (Rkip1 (-/-)) mice were characterised in terms of pancreatic and glucose homeostasis, including morphological and functional analysis. Glucose tolerance and insulin sensitivity were examined, followed by assessment of glucose-induced insulin secretion in isolated islets and beta cell mass quantification through morphometry. Further characterisation included determination of endocrine and exocrine proliferation, apoptosis, MAPK activation and whole genome gene expression assays. Capacity to reverse a diabetic phenotype was assessed in adult Rkip1 (-/-) mice after streptozotocin treatment. RESULTS: Rkip1 (-/-) mice exhibit a moderately larger pancreas and increased beta cell mass and pancreatic insulin content, which correlate with an overall improvement in whole body glucose tolerance. This phenotype is established in young postnatal stages and involves enhanced cellular proliferation without significant alterations in cell death. Importantly, adult Rkip1 (-/-) mice exhibit rapid reversal of streptozotocin-induced diabetes compared with control mice. CONCLUSIONS/INTERPRETATION: These data implicate RKIP1 in the regulation of pancreatic growth and beta cell expansion, thus revealing RKIP1 as a potential pharmacological target to promote beta cell regeneration. Pancreatic gene expression of Rkip-1 (Raf kinase inhibitor 1) knockout (KO) and wild type (WT) mice, including three biological replicates in each group.