Single-Cell Transcriptomics Links Loss of Human Pancreatic β-Cell Identity to ER Stress
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE263565 | GEO | 2024/04/13
REPOSITORIES: GEO
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Project description:Generation of mature cells with stable functional identities is crucial for developing cell-based replacement therapies. Current global efforts to produce insulin-secreting beta-like cells to treat diabetes are hampered by the lack of tools to reliably assess cellular identity. We conducted a thorough single-cell transcriptomics meta-analysis to generate robust genesets defining the identity of human adult alpha-, beta-, gamma- and delta-cells. After extensive validation, we showed the efficacy of the novel genesets to define changes in islet cell identity, whether during embryonic development or in different experimental setups aimed at developing new functional glucose-responsive insulin-secreting cells, such as through pluripotent stem-cell differentiation or islet cell reprogramming protocols. Finally, we evaluated whether the perturbed metabolic conditions typical of diabetes influence islet cell identity. We observed that alpha-cells from diabetic donors exhibit an altered phenotype. In conclusion, these novel genesets represent valuable tools that robustly benchmark gain and loss in islet cell identity traits.
2021-06-26 | GSE150724 | GEO
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:Dedifferentiation of pancreatic beta cells may reduce islet function in type 2 diabetes (T2D). However, the prevalence, plasticity and functional consequences of this cellular state remain unknown. We employed single-cell RNAseq to detail the maturation program of alpha and beta cells during human ontogeny. We show that although both alpha and beta cells mature in part by repressing non-endocrine genes, alpha-cells retain hallmarks of an immature state, while beta-cells attain a full beta-cell specific gene expression program. In islets from T2D donors, both alpha- and beta-cells return to a less mature expression profile, de-repressing the juvenile genetic program and exocrine genes while increasing expression of exocytosis, inflammation and stress response signaling pathways. These changes support the increased proportion of beta-cells displaying suboptimal function observed in T2D islets. These findings provide new insights into the molecular program underlying islet cell maturation during human ontogeny and the loss of transcriptomic maturity that occurs in islets of type 2 diabetics.
2020-10-01 | GSE154126 | GEO
Project description:Generating insulin-producing β-cells from human induced pluripotent stem cells is a promising cell replacement therapy aimed at improving or curing certain forms of diabetes. Nevertheless, despite important recent advances, the efficient production of functionally mature β-cells is yet to be achieved, with most current differentiation protocols generating a heterogeneous population comprising of subpopulation of cells expressing different islet hormones, including hybrid polyhormonal entities. A solution to this issue is transplanting end-stages differentiating cells into living hosts, which was demonstrated to majorly improve β-cell maturation. Yet, to date, the cellular and molecular mechanisms underlying the transplanted cells response to the in vivo environment exposure was not yet properly characterized. Here we use global proteomics and large-scale imaging techniques aimed at demultiplexing and filtering cellular processes and molecular signatures modulated by the immediate in vivo effect. We show that in vivo exposure swiftly confines in vitro generated human pancreatic progenitors to single hormone expression. The global proteome landscape of the transplanted cells was closer to the one presented by native human islets, especially in regard to energy metabolism and redox balance. Moreover our study indicates a possible link between these processed and certain epigenetic regulators involved in maintenance and propagation of the islet cells identity. Pathway analysis predicted HNF1A and HNF4A as key regulators controlling the in vivo islet-promoting response, with experimental evidence confirming their involvement in confining islet cell identity. To our knowledge this is the first study demultiplexing the immediate response of the transplanted pancreatic progenitors to in vivo exposure.
2020-02-12 | PXD015955 | Pride
Project description:Loss of pancreatic Beta cell mass, identity, and function contribute to the development of diabetes. Here, we show that the endoplasmic reticulum (ER) calcium sensor, stromal interaction molecule 1 (STIM1), is critical for the maintenance of Beta cell function in female mice. When mice with Beta cell- specific deletion of STIM1 (STIM1-delta-Beta) were challenged with high-fat diet, Beta cell dysfunction was observed in female, but not male, mice. Impaired glucose tolerance was accompanied by reductions in Beta cell mass, a concomitant increase in alpha cell mass, and significant reductions in the expression of markers of Beta cell maturity, including MafA and UCN3. Mechanistic assays demonstrated that the sexually dimorphic phenotype observed in STIM1-Delta-Beta mice was due in part to loss of signaling through the noncanonical 17-Beta estradiol receptor, GPER1. Together, these data suggest that STIM1 orchestrates pancreatic Beta cell function and identity through GPER1- mediated estradiol signaling.
2022-07-20 | MSV000089927 | MassIVE
Project description:Objective: beta-cell dedifferentiation has been revealed as a pathological mechanism underlying pancreatic dysfunction in diabetes. However, exactly how such dedifferentiation process affects beta-cell gene expression and islet microenvironment remains incompletely understood Method: We performed single-cell RNA-Sequencing (RNA-seq) in islets obtained from beta-cell-specific miR-7a2 overexpressing mice (Tg7), a murine model of beta-cell dedifferentiation and diabetes. Results: Single-cell RNA-seq revealed that beta-cell dedifferentiation is associated with the induction of genes associated with epithelial to mesenchymal transition (EMT) specifically in beta-cells of diabetic (12-week-old) Tg7 mice. These molecular changes are associated with a weakening of beta-cell:beta-cell contacts, increased extracellular matrix (ECM) deposition and TGFb-dependent islet fibrosis. We find that the mesenchymal reprogramming of beta-cells is explained in part by the downregulation of Pdx1 and its inability to regulate a myriad of target genes preserving the epithelial cell phenotype. Notable among epithelial genes transactivated by Pdx1 is Ovol2, a transcriptional repressor of the EMT transcription factor ZEB2. Following compromised beta-cell identity, the reduction of Pdx1 mRNA levels decreases Ovol2 gene expression, which triggers mesenchymal reprogramming of beta-cells through the induction of Zeb2. Finally, we provided evidence that EMT signalling associated with the upregulation of Zeb2 expression is a molecular feature of islet of T2D subjects. Conclusions: Our study indicates that beta-cell dedifferentiation triggers a chronic response to tissue injury, which alters the pancreatic islet microenvironment and contribute to islet fibrosis. It suggests that regulators of EMT signalling may represent novel therapeutic targets for the treatment of beta-cell dysfunction and fibrosis in T2D.
2021-07-21 | GSE171252 | GEO
Project description:Type 2 diabetes (T2D) is associated with compromised identity of insulin-producing pancreatic islet beta (β) cells, characterized by inappropriate production of other islet cell-enriched hormones. Here we examined how hormone misexpression was influenced by the MAFA and MAFB transcription factors, closely related proteins that maintain islet cell function. Mice specifically lacking MafA in β cells demonstrated broad, population-wide changes in hormone gene expression with an overall gene signature closely resembling islet gastrin (Gast)-positive cells generated under conditions of chronic hyperglycemia and obesity. A human b cell line deficient in MAFB, but not one lacking MAFA, also produced a gastrin (GAST)-positive gene expression pattern. In addition, GAST was detected in human T2D β cells with low levels of MAFB. Moreover, evidence is provided that human MAFB can directly repress GAST gene transcription. These results support a novel, species-specific role for MafA and MAFB in maintaining adult mouse and human β cell identity, respectively, by repressing expression of Gast/GAST and other non-b cell hormones.
2023-05-01 | GSE230728 | GEO
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:Objective: beta-cell dedifferentiation has been revealed as a pathological mechanism underlying pancreatic dysfunction in diabetes. However, exactly how such dedifferentiation process affects beta-cell gene expression and islet microenvironment remains incompletely understood Method: We performed bulk in islets obtained from beta-cell-specific miR-7a2 overexpressing mice (Tg7), a murine model of beta-cell dedifferentiation and diabetes. Results: Bulk RNA-seq revealed that beta-cell dedifferentiation is associated with the induction of genes associated with epithelial to mesenchymal transition (EMT) in pre-diabetic (2-week-old) and diabetic (12-week-old) Tg7mice. These molecular changes are associated with a weakening of beta-cell:beta-cell contacts, increased extracellular matrix (ECM) deposition and TGFb-dependent islet fibrosis. We find that the mesenchymal reprogramming of beta-cells is explained in part by the downregulation of Pdx1 and its inability to regulate a myriad of target genes preserving the epithelial cell phenotype. Notable among epithelial genes transactivated by Pdx1 is Ovol2, a transcriptional repressor of the EMT transcription factor ZEB2. Following compromised beta-cell identity, the reduction of Pdx1 mRNA levels decreases Ovol2 gene expression, which triggers mesenchymal reprogramming of beta-cells through the induction of Zeb2. Finally, we provided evidence that EMT signalling associated with the upregulation of Zeb2 expression is a molecular feature of islet of T2D subjects. Conclusions: Our study indicates that beta-cell dedifferentiation triggers a chronic response to tissue injury, which alters the pancreatic islet microenvironment and contribute to islet fibrosis. It suggests that regulators of EMT signalling may represent novel therapeutic targets for the treatment of beta-cell dysfunction and fibrosis in T2D.
2021-07-21 | GSE171251 | GEO
Project description:Abcc8 (sulfonylurea receptor 1, SUR1) is an essential part of the ATP-sensitive potassium channel necessary for coupling energy metabolism and membrane potential. In this study we assessed the impact of eliminating Abcc8 on islet morphology, beta-cell identity, and gene expression. Beta cells were isolated by FACS from 60 day old mice based on expression of a MIP-GFP transgene.
2017-06-02 | E-MTAB-4726 | biostudies-arrayexpress