| 1. |
- Ottosson-Laakso, Emilia, et al.
(författare)
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Glucose-induced Changes in Gene Expression in Human Pancreatic Islets - Causes or Consequences of Chronic Hyperglycemia
- 2017
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 66:12, s. 3013-3028
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Tidskriftsartikel (refereegranskat)abstract
- Dysregulation of gene expression in islets from type 2 diabetic patients might be causally involved in the development of hyperglycemia or it could develop as a consequence of hyperglycemia, i.e. glucotoxicity. To separate the genes potentially causally involved in pathogenesis from those likely to be secondary to the hyperglycemia we exposed islets from human donors to normal or high glucose concentrations for 24 hours and analyzed gene expression. We compared these findings with gene expression in islets from donors with normal glucose tolerance (NGT) and hyperglycemia (HG, including T2D). The genes whose expression changed in the same direction after short-term glucose exposure as in T2D were considered most likely to be a consequence of hyperglycemia. Genes whose expression changed in HG but not after short-term glucose exposure, in particular genes that also correlated with insulin secretion, were considered the strongest candidates for causal involvement in T2D. E.g. ERO1LB, DOCK10, IGSF11 and PRR14L were down-regulated in HG and correlated positively with insulin secretion suggesting a protective role while TMEM132C was up-regulated in HG and correlated negatively with insulin secretion suggesting a potential pathogenic role.This study provides a catalogue of gene expression changes in human pancreatic islets after exposure to glucose.
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| 2. |
- Viñuela, Ana, et al.
(författare)
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Genetic variant effects on gene expression in human pancreatic islets and their implications for T2D
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1, s. 4912-4912
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Tidskriftsartikel (refereegranskat)abstract
- Most signals detected by genome-wide association studies map to non-coding sequence and their tissue-specific effects influence transcriptional regulation. However, key tissues and cell-types required for functional inference are absent from large-scale resources. Here we explore the relationship between genetic variants influencing predisposition to type 2 diabetes (T2D) and related glycemic traits, and human pancreatic islet transcription using data from 420 donors. We find: (a) 7741 cis-eQTLs in islets with a replication rate across 44 GTEx tissues between 40% and 73%; (b) marked overlap between islet cis-eQTL signals and active regulatory sequences in islets, with reduced eQTL effect size observed in the stretch enhancers most strongly implicated in GWAS signal location; (c) enrichment of islet cis-eQTL signals with T2D risk variants identified in genome-wide association studies; and (d) colocalization between 47 islet cis-eQTLs and variants influencing T2D or glycemic traits, including DGKB and TCF7L2. Our findings illustrate the advantages of performing functional and regulatory studies in disease relevant tissues.
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