Conservation of chromatin loops between mouse and human beta cells
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE196729 | GEO | 2024/01/31
REPOSITORIES: GEO
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Project description:Using eHi-C to map chromatin loops in mouse beta cells
| PRJNA749602 | ENA
Project description:Objective: Transcriptional complex activity drives the development and function of pancreatic islet cells to allow for proper glucose regulation. Our prior work highlighted that the LIM-homeodomain transcription factor (TF), Islet-1 (Isl1), and its interacting co-regulator, Ldb1, are vital effectors of developing and adult β-cells. We further found that a member of the Single Stranded DNA-Binding Protein (SSBP) co-regulator family, SSBP3, interacts with Isl1 and Ldb1 in β-cells and primary islets (mouse and human) to impact β-cell target genes MafA and Glp1R. Members of the SSBP family stabilize TF complexes by binding directly to Ldb1 and protecting the complex from ubiquitin-mediated turnover. In this study, we hypothesized that SSBP3 would have critical roles in pancreatic islet cell development and function in vivo, similar to the Isl1::Ldb1 complex. Methods: We first generated a novel SSBP3 LoxP allele mouse line, where Cre-mediated recombination imparts a predicted early protein termination. We bred this mouse to constitutive Cre lines (Pdx1- and Pax6-driven) to recombine of SSBP3 in the developing pancreas and islet (SSBP3DeltaPanc and SSBP3DeltaIslet), respectively. We assessed glucose tolerance and used immunofluorescence to detect changes in islet cell abundance and markers of β-cell identity and function. Using an inducible Cre system we also deleted SSBP3 in the adult β-cell, a model termed SSBP3Deltaβ-cell. We measured glucose tolerance as well as glucose-stimulated insulin secretion (GSIS), both in vivo and in isolated islets in vitro. Using islets from control and SSBP3Deltaβ-cell we conducted RNA-Seq and compared our results to published datasets for similar β-cell specific Ldb1 and Isl1 knockouts to identify commonly regulated target genes. Results: SSBP3DeltaPanc and SSBP3DeltaIslet neonates present with hyperglycemia. SSBP3DeltaIslet mice are glucose intolerant by P21 and exhibit a reduction of β-cell maturity markers MafA, Pdx1, and UCN3. We observe disruptions in islet cell architecture with an increase in glucagon+ α-cells and ghrelin+ ε-cells at P10. Inducible loss of β-cell SSBP3 in SSBP3Deltaβ-cell causes hyperglycemia, glucose intolerance, and reduced GSIS. Transcriptomic analysis of 14-week SSBP3Deltaβ-cell islets revealed a decrease in β-cell function gene expression (Ins, MafA, Ucn3), increased stress and dedifferentiation markers (Neurogenin-3, Aldh1a3, Gastrin), and shared differentially expressed genes between SSBP3, Ldb1, and Isl1 in adult β-cells. Conclusions: SSBP3 drives proper islet development and identity, where its loss causes altered islet-cell abundance and glucose regulatory function. β-cell SSBP3 is required for GSIS and glucose homeostasis, at least partially through shared regulation of Ldb1 and Isl1 target genes.
2023-08-16 | GSE232750 | GEO
Project description:Recent advances in the understanding of the genetics of type 2 diabetes (T2D) susceptibility have focused attention on the regulation of transcriptional activity within the pancreatic beta-cell. MicroRNAs (miRNAs) represent an important component of regulatory control, and have proven roles in the development of human disease and control of glucose homeostasis. We set out to establish the miRNA profile of human pancreatic islets and of enriched beta-cell populations, and to explore their potential involvement in T2D susceptibility. We used Illumina small RNA sequencing to profile the miRNA fraction in three preparations each of primary human islets and of enriched beta-cells generated by fluorescence-activated cell sorting. In total, 366 miRNAs were found to be expressed (i.e. >100 cumulative reads) in islets and 346 in beta-cells; of the total of 384 unique miRNAs, 328 were shared. A comparison of the islet-cell miRNA profile with those of 15 other human tissues identified 40 miRNAs predominantly expressed (i.e. >50% of all reads seen across the tissues) in islets. Several highly-expressed islet miRNAs, such as miR-375, have established roles in the regulation of islet function, but others (e.g. miR-27b-3p, miR-192-5p) have not previously been described in the context of islet biology. As a first step towards exploring the role of islet-expressed miRNAs and their predicted mRNA targets in T2D pathogenesis, we looked at published T2D association signals across these sites. We found evidence that predicted mRNA targets of islet-expressed miRNAs were globally enriched for signals of T2D association (p-values <0.01, q-values <0.1). At six loci with genome-wide evidence for T2D association (AP3S2, KCNK16, NOTCH2, SCL30A8, VPS26A, and WFS1) predicted mRNA target sites for islet-expressed miRNAs overlapped potentially causal variants. In conclusion, we have described the miRNA profile of human islets and beta-cells and provide evidence linking islet miRNAs to T2D pathogenesis. Examination of the miRNA profiles in 3 preparations of isolated pancreatic islets and 3 preparations of FACS-enriched pancreatic beta-cells
2013-06-07 | E-GEOD-47720 | biostudies-arrayexpress
Project description:Altered islet architecture is associated with β cell dysfunction and Type 2 Diabetes (T2D) progression, but molecular effectors of islet spatial organization remain mostly unknown. Although Notch signaling is known to regulate pancreatic development, we observed “re-activated” β cell Notch activity in obese mouse models. To test the repercussions and reversibility of Notch effects, we generated doxycycline-dependent, β cell-specific Notch gain-of-function mice. As predicted, we found that Notch activation in post-natal β cells impaired glucose stimulated insulin secretion (GSIS) and glucose intolerance, but we observed a surprising remnant glucose intolerance after doxycycline withdrawal and cessation of Notch activity, associated with a marked disruption of normal islet architecture. Transcriptomic screening of Notch-active islets revealed increased Ephrin signaling. Commensurately, exposure to Ephrin ligands increased β cell repulsion, and impaired murine and human pseudo-islet formation. Consistent with our mouse data, Notch and Ephrin signaling are increased in metabolically-inflexible β cells in patients with T2D. These studies suggest than islet architecture can be permanently altered by β cell Notch/Ephrin signaling during a morphogenetic window in early life.
2022-02-21 | GSE193888 | GEO
Project description:The remarkable differentiation capacity of pluripotent stem cells into any adult cell types have enabled researchers to model human embryonic development and disease process in dishes, as well as deriving specialized cells for replacing damaged tissues. Type 1 diabetes is a degenerative disease characterized by autoimmune destruction of the insulin-producing beta islet cells in the pancreas. Recent advances have led to the establishment of different methods to direct differentiation of human or mouse pluripotent stem cells toward beta cell lineages. However, existing strategies have not yet succeeded in generating fully functional beta cells in vitro. Thus, it remains a major challenge to identify novel regulators of beta cell differentiation and maturation, and the islet-specific genetic and epigenetic regulatory networks are logical targets. To obtain a comprehensive view of the microRNA expression pattern during in vitro directed differentiation of hPSC into pancreatic beta islet cells, we collected 16 samples of 6 stages of differentiated derivatives, 2 samples of human fetal pancreas and 5 samples of purified human beta islet cells for analysis. With these samples, we performed genome-wide microRNA expression profiling using the Illumina Human v2 MicroRNA Expression BeadChips (1,146 assays).
2012-11-07 | E-GEOD-42093 | biostudies-arrayexpress
Project description:The remarkable differentiation capacity of pluripotent stem cells into any adult cell types have enabled researchers to model human embryonic development and disease process in dishes, as well as deriving specialized cells for replacing damaged tissues. Type 1 diabetes is a degenerative disease characterized by autoimmune destruction of the insulin-producing beta islet cells in the pancreas. Recent advances have led to the establishment of different methods to direct differentiation of human or mouse pluripotent stem cells toward beta cell lineages. However, existing strategies have not yet succeeded in generating fully functional beta cells in vitro. Thus, it remains a major challenge to identify novel regulators of beta cell differentiation and maturation, and the islet-specific genetic and epigenetic regulatory networks are logical targets. To obtain a comprehensive view of the mRNA expression pattern during in vitro directed differentiation of hPSC into pancreatic beta islet cells, we collected 16 samples of 6 stages of differentiated derivatives, 2 samples of human fetal pancreas and 5 samples of purified human beta islet cells for analysis. With these samples, we performed genome-wide mRNA expression profiling using the Illumina Infinium HT-12 v4 Gene Expression BeadArray.
2012-11-07 | E-GEOD-42094 | biostudies-arrayexpress
Project description:R-loop is a naturally formed three-strand nucleic acid structure that was reported to take part in multiple biological processes. In our study, we firstly mapped R-loop genomic distribution in mammalian meiotic cells by genome-wide S9.6 CUT & Tag seq. R-loop mainly distributed at promoter-related regions, and combined with systematically transcriptome analysis showed R-loop was closely related to transcription in the meiotic process. Moreover, we verified the conclusion by constructing conditional knockout mice of Rnaseh1, which delete the R-loop endonuclease before meiosis entry. Lack of RNase H1 caused mice completely sterile with R-loop accumulation and abnormal DSB repairing in spermatocytes. Further analysis showed R-loop accumulation in leptotene/zygotene influenced transcriptional regulation in the pachytene stage. Thus, mutual regulation of R-loop and transcription plays an essential role in spermatogenesis.
2023-02-01 | GSE193401 | GEO
Project description:Endocrine enriched genes in adult islet beta cells were identified and compared with that of induced beta cells (with M3 transcription factors) in adult. The control sample is non-beta pancreatic cells. Gene expression profile comparison of 3 samples, 3 independent repeats for each sample indicate a high degree of similarity between endogenous and induced beta cells in adult mouse.
2008-07-08 | E-GEOD-12025 | biostudies-arrayexpress
Project description:Alpha TC1 (αTC1) and Beta-TC-6 (βTC6) mouse islet cell lines are cellular models of islet (dys)function and type 2 diabetes (T2D). However, genomic characteristics of these cells, and their similarities to primary islet alpha and beta cells, are undefined. Here, we report the epigenomic (ATAC-seq) and transcriptomic (RNA-seq) landscapes of αTC1 and βTC6 cells. Each cell type exhibits hallmarks of its primary islet cell counterpart including cell-specific expression of beta (e.g., Pdx1) and alpha (e.g., Arx) cell transcription factors (TFs), and enrichment of binding motifs for these TFs in αTC1/βTC6 cis-regulatory elements. αTC1/βTC6 transcriptomes overlap significantly with the transcriptomes of primary mouse/human alpha and beta cells. Our data further indicate that ATAC-seq detects cell-specific regulatory elements for cell types comprising ≥ 20% of a mixed cell population. We identified αTC1/βTC6 cis-regulatory elements orthologous to those containing type 2 diabetes (T2D)-associated SNPs in human islets for 33 loci, suggesting these cells’ utility to dissect T2D molecular genetics in these regions. Together, these maps provide important insights into the conserved regulatory architecture between αTC1/βTC6 and primary islet cells that can be leveraged in functional (epi)genomic approaches to dissect the genetic and molecular factors controlling islet cell identity and function.
2017-09-20 | GSE99954 | GEO
Project description:Pancreatic islet endocrine cell and endothelial cell (EC) interactions mediated by vascular endothelial growth factor-A (VEGF-A) signaling are important for islet endocrine cell differentiation and the formation of highly vascularized islets. To dissect how VEGF-A signaling modulates intra-islet vasculature and innervation, islet microenvironment, and β cell mass, we transiently increased VEGF-A production by β cells. VEGF-A induction dramatically increased the number of intra-islet ECs but led to β cell loss. After withdrawal of the VEGF-A stimulus, β cell mass, function, and islet structure normalized as a result of a robust, but transient, burst in proliferation of pre-existing β cells. Bone marrow-derived macrophages (MΦs) recruited to the site of β cell injury were crucial for the β cell proliferation, which was independent of pancreatic location and circulating factors such as glucose. Identification of the signals responsible for the proliferation of adult, terminally differentiated β cells will improve strategies aimed at β cell regeneration and expansion. Examination of RNA profiles from isolated whole islets from RIP-rtTA; TetO-VEGF-A mice with no doxycycline (Dox) treatment (3 samples) and after 1 week of Dox (3 sample); and islet-derived macrophages (3 samples) and endothelial cells (3 samples) isolated from dispersed purified islets from RIP-rtTA; TetO-VEGF-A mice after 1 week Dox treatment by fluorescence-activated cell sorting using antibodies against CD11b and CD31, respectively.
2015-09-01 | E-GEOD-72546 | biostudies-arrayexpress