| 1. |
- Akerman, Ildem, et al.
(författare)
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Human Pancreatic β Cell lncRNAs Control Cell-Specific Regulatory Networks
- 2017
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Ingår i: Cell Metabolism. - : Elsevier BV. - 1550-4131. ; 25:2, s. 400-411
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have uncovered thousands of long non-coding RNAs (lncRNAs) in human pancreatic β cells. β cell lncRNAs are often cell type specific and exhibit dynamic regulation during differentiation or upon changing glucose concentrations. Although these features hint at a role of lncRNAs in β cell gene regulation and diabetes, the function of β cell lncRNAs remains largely unknown. In this study, we investigated the function of β cell-specific lncRNAs and transcription factors using transcript knockdowns and co-expression network analysis. This revealed lncRNAs that function in concert with transcription factors to regulate β cell-specific transcriptional networks. We further demonstrate that the lncRNA PLUTO affects local 3D chromatin structure and transcription of PDX1, encoding a key β cell transcription factor, and that both PLUTO and PDX1 are downregulated in islets from donors with type 2 diabetes or impaired glucose tolerance. These results implicate lncRNAs in the regulation of β cell-specific transcription factor networks.
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| 2. |
- Atla, Goutham, et al.
(författare)
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Genetic regulation of RNA splicing in human pancreatic islets
- 2022
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Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1474-760X. ; 23, s. 1-28
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundNon-coding genetic variants that influence gene transcription in pancreatic islets play a major role in the susceptibility to type 2 diabetes (T2D), and likely also contribute to type 1 diabetes (T1D) risk. For many loci, however, the mechanisms through which non-coding variants influence diabetes susceptibility are unknown.ResultsWe examine splicing QTLs (sQTLs) in pancreatic islets from 399 human donors and observe that common genetic variation has a widespread influence on the splicing of genes with established roles in islet biology and diabetes. In parallel, we profile expression QTLs (eQTLs) and use transcriptome-wide association as well as genetic co-localization studies to assign islet sQTLs or eQTLs to T2D and T1D susceptibility signals, many of which lack candidate effector genes. This analysis reveals biologically plausible mechanisms, including the association of T2D with an sQTL that creates a nonsense isoform in ERO1B, a regulator of ER-stress and proinsulin biosynthesis. The expanded list of T2D risk effector genes reveals overrepresented pathways, including regulators of G-protein-mediated cAMP production. The analysis of sQTLs also reveals candidate effector genes for T1D susceptibility such as DCLRE1B, a senescence regulator, and lncRNA MEG3.ConclusionsThese data expose widespread effects of common genetic variants on RNA splicing in pancreatic islets. The results support a role for splicing variation in diabetes susceptibility, and offer a new set of genetic targets with potential therapeutic benefit.
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| 3. |
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| 4. |
- Latreille, Mathieu, et al.
(författare)
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MicroRNA-7a regulates pancreatic beta cell function
- 2014
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Ingår i: Journal of Clinical Investigation. - 0021-9738. ; 124:6, s. 2722-2735
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Tidskriftsartikel (refereegranskat)abstract
- Dysfunctional microRNA (miRNA) networks contribute to inappropriate responses following pathological stress and are the underlying cause of several disease conditions. In pancreatic beta cells, miRNAs have been largely unstudied and little is known about how specific miRNAs regulate glucose-stimulated insulin secretion (GSIS) or impact the adaptation of beta cell function to metabolic stress. In this study, we determined that miR-7 is a negative regulator of GSIS in beta cells. Using Mir7a2 deficient mice, we revealed that miR-7a2 regulates beta cell function by directly regulating genes that control late stages of insulin granule fusion with the plasma membrane and ternary SNARE complex activity. Transgenic mice overexpressing miR-7a in beta cells developed diabetes due to impaired insulin secretion and beta cell dedifferentiation. Interestingly, perturbation of miR-7a expression in beta cells did not affect proliferation and apoptosis, indicating that miR-7 is dispensable for the maintenance of endocrine beta cell mass. Furthermore, we found that miR-7a levels are decreased in obese/ diabetic mouse models and human islets from obese and moderately diabetic individuals with compensated beta cell function. Our results reveal an interconnecting miR-7 genomic circuit that regulates insulin granule exocytosis in pancreatic beta cells and support a role for miR-7 in the adaptation of pancreatic p cell function in obesity and type 2 diabetes.
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| 5. |
- Miguel-Escalada, Irene, et al.
(författare)
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Human pancreatic islet three-dimensional chromatin architecture provides insights into the genetics of type 2 diabetes
- 2019
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 51:7, s. 1137-1148
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Tidskriftsartikel (refereegranskat)abstract
- Genetic studies promise to provide insight into the molecular mechanisms underlying type 2 diabetes (T2D). Variants associated with T2D are often located in tissue-specific enhancer clusters or super-enhancers. So far, such domains have been defined through clustering of enhancers in linear genome maps rather than in three-dimensional (3D) space. Furthermore, their target genes are often unknown. We have created promoter capture Hi-C maps in human pancreatic islets. This linked diabetes-associated enhancers to their target genes, often located hundreds of kilobases away. It also revealed >1,300 groups of islet enhancers, super-enhancers and active promoters that form 3D hubs, some of which show coordinated glucose-dependent activity. We demonstrate that genetic variation in hubs impacts insulin secretion heritability, and show that hub annotations can be used for polygenic scores that predict T2D risk driven by islet regulatory variants. Human islet 3D chromatin architecture, therefore, provides a framework for interpretation of T2D genome-wide association study (GWAS) signals.
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| 6. |
- Nano, Rita, et al.
(författare)
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Heterogeneity of Human Pancreatic Islet Isolation Around Europe : Results of a Survey Study
- 2020
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Ingår i: Transplantation. - : LIPPINCOTT WILLIAMS & WILKINS. - 0041-1337 .- 1534-6080. ; 104:1, s. 190-196
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Tidskriftsartikel (refereegranskat)abstract
- Background: Europe is currently the most active region in the field of pancreatic islet transplantation, and many of the leading groups are actually achieving similar good outcomes. Further collaborative advances in the field require the standardization of islet cell product isolation processes, and this work aimed to identify differences in the human pancreatic islet isolation processes within European countries.Methods: A web-based questionnaire about critical steps, including donor selection, pancreas processing, pancreas perfusion and digestion, islet counting and culture, islet quality evaluation, microbiological evaluation, and release criteria of the product, was completed by isolation facilities participating at the Ninth International European Pancreas and Islet Transplant Association (EPITA) Workshop on Islet-Beta Cell Replacement in Milan.Results: Eleven islet isolation facilities completed the questionnaire. The facilities reported 445 and 53 islet isolations per year over the last 3 years from deceased organ donors and pancreatectomized patients, respectively. This activity resulted in 120 and 40 infusions per year in allograft and autograft recipients, respectively. Differences among facilities emerged in donor selection (age, cold ischemia time, intensive care unit length, amylase concentration), pancreas procurement, isolation procedures (brand and concentration of collagenase, additive, maximum acceptable digestion time), quality evaluation, and release criteria for transplantation (glucose-stimulated insulin secretion tests, islet numbers, and purity). Moreover, even when a high concordance about the relevance of one parameter was evident, thresholds for the acceptance were different among facilities.Conclusions: The result highlighted the presence of a heterogeneity in the islet cell product process and product release criteria.
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| 7. |
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| 8. |
- Nano, Rita, et al.
(författare)
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Islets for Research : Nothing Is Perfect, but We Can Do Better
- 2019
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Ingår i: Diabetes. - : AMER DIABETES ASSOC. - 0012-1797 .- 1939-327X. ; 68:8, s. 1541-1543
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Tidskriftsartikel (refereegranskat)abstract
- In December 2018, Diabetes and Diabetologia began requiring authors of papers reporting data obtained from studies on human islets to report critical characteristics of the human islets used for research. The islet community was asked to provide feedback on it. Here is the contribution by the European Consortium for Islet Transplantation.
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| 9. |
- Piemonti, Lorenzo, et al.
(författare)
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US food and drug administration (FDA) panel endorses islet cell treatment for type 1 diabetes : A pyrrhic victory?
- 2021
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Ingår i: Transplant International. - : John Wiley & Sons. - 0934-0874 .- 1432-2277. ; 34:7, s. 1182-1186
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Allogeneic islet transplantation is a standard of care treatment for patients with labile type 1 diabetes in many countries around the world, including Japan, the United Kingdom, Australia, much of continental Europe, and parts of Canada. The United States is now endorsing islet cell treatment for type 1 diabetes, but the FDA has chosen to consider islets as a biologic that requires licensure, making the universal implementation of the procedure in the clinic very challenging and opening the manufacture of islet grafts to private companies. The commercialization of human tissues raises significant legal and ethical issues and ironically leads to a situation where treatments developed as a result of the scientific and economic efforts of academia over several decades become exploited exclusively by for-profit entities.
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