| 11. |
- Asplund, Olof, et al.
(författare)
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Islet Gene View-a tool to facilitate islet research
- 2022
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Ingår i: Life Science Alliance. - : Life Science Alliance, LLC. - 2575-1077. ; 5:12
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Tidskriftsartikel (refereegranskat)abstract
- Characterization of gene expression in pancreatic islets and its alteration in type 2 diabetes (T2D) are vital in understanding islet function and T2D pathogenesis. We leveraged RNA sequencing and genome-wide genotyping in islets from 188 donors to create the Islet Gene View (IGW) platform to make this information easily accessible to the scientific community. Expression data were related to islet phenotypes, diabetes status, other islet-expressed genes, islet hormone-encoding genes and for expression in insulin target tissues. The IGW web application produces output graphs for a particular gene of interest. In IGW, 284 differentially expressed genes (DEGs) were identified in T2D donor islets compared with controls. Forty percent of DEGs showed cell-type enrichment and a large proportion significantly co-expressed with islet hormone-encoding genes; glucagon (GCG, 56%), amylin (IAPP, 52%), insulin (INS, 44%), and somatostatin (SST, 24%). Inhibition of two DEGs, UNC5D and SERPINE2, impaired glucose-stimulated insulin secretion and impacted cell survival in a human beta-cell model. The exploratory use of IGW could help designing more comprehensive functional follow-up studies and serve to identify therapeutic targets in T2D.
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| 12. |
- Axelsson, Annika S., et al.
(författare)
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Sulforaphane reduces hepatic glucose production and improves glucose control in patients with type 2 diabetes
- 2017
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Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 9:394
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Tidskriftsartikel (refereegranskat)abstract
- A potentially useful approach for drug discovery is to connect gene expression profiles of disease-affected tissues ("disease signatures") to drug signatures, but it remains to be shown whether it can be used to identify clinically relevant treatment options. We analyzed coexpression networks and genetic data to identify a disease signature for type 2 diabetes in liver tissue. By interrogating a library of 3800 drug signatures, we identified sulforaphane as a compound that may reverse the disease signature. Sulforaphane suppressed glucose production from hepatic cells by nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2) and decreased expression of key enzymes in gluconeogenesis. Moreover, sulforaphane reversed the disease signature in the livers from diabetic animals and attenuated exaggerated glucose production and glucose intolerance by a magnitude similar to that of metformin. Finally, sulforaphane, provided as concentrated broccoli sprout extract, reduced fasting blood glucose and glycated hemoglobin (HbA1c) in obese patients with dysregulated type 2 diabetes.
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| 13. |
- Axling, Ulrika, et al.
(författare)
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A low glycaemic diet improves oral glucose tolerance but has no effect on β-cell function in C57BL/6J mice.
- 2010
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Ingår i: Diabetes, Obesity and Metabolism. - : Wiley. - 1462-8902. ; 12:11, s. 976-982
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Tidskriftsartikel (refereegranskat)abstract
- AIM: Clinical studies have suggested a role for dietary glycaemic index (GI) in body weight regulation and diabetes risk. Here, we investigated the long-term metabolic effects of low and high glycaemic diets using the C57BL/6J mouse model. METHODS: Female C57BL/6J mice were fed low or high glycaemic starch in either low-fat or medium-fat diets for 22 weeks. Oral and intravenous glucose tolerance tests were performed to investigate the effect of the experimental diets on glucose tolerance and insulin resistance. RESULTS: In this study, a high glycaemic diet resulted in impaired oral glucose tolerance compared to a low glycaemic diet. This effect was more pronounced in the group fed a medium-fat diet, suggesting that a lower dietary fat content ameliorates the negative effect of a high glycaemic diet. No effect on body weight or body fat content was observed in either a low-fat diet or a medium-fat diet. Static incubation of isolated islets did not show any differences in basal (3.3 mM glucose) or glucose-stimulated (8.6 and 16.7 mM glucose) insulin secretion between mice fed a low or high glycaemic diet. CONCLUSION: Together, our data suggest that the impaired glucose tolerance seen after a high glycaemic diet is not explained by altered β-cell function.
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| 14. |
- Axling, Ulrika, et al.
(författare)
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Metabolic effects of whole grain wheat and whole grain rye in the C57BL/6J mouse.
- 2010
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Ingår i: Nutrition. - : Elsevier BV. - 1873-1244 .- 0899-9007. ; 26, s. 230-239
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: A diet rich in whole grain cereals is suggested to protect against type 2 diabetes and facilitate body weight regulation. However, little is known about the impact of different cereals and the underlying mechanisms. The objective of this study was to compare the long-term metabolic effects of diets supplemented with whole grain wheat or whole grain rye in the C57BL/6J mouse. METHODS: Mice were fed the whole grain supplements in a low-fat background diet for 22 wk. Oral and intravenous glucose tolerance tests were performed during the study and in vitro insulin secretion assays were performed at the end of the study. Body weight, energy intake, body fat content, and plasma parameters were measured during the study. RESULTS: A dietary supplement of whole grain rye suppressed body weight gain and resulted in significantly decreased adiposity, plasma leptin, total plasma cholesterol, and triacylglycerols compared with a supplement of whole grain wheat. Also, a slight improvement in insulin sensitivity was observed in the rye group compared with the wheat group. The decreases in body weight and adiposity were observed in the absence of differences in energy intake. CONCLUSION: Long-term administration of whole grain rye evokes a different metabolic profile compared with whole grain wheat in the C57BL/6J mouse, the primary difference being that whole grain rye reduces body weight and adiposity compared with whole grain wheat. In addition, whole grain rye slightly improves insulin sensitivity and lowers total plasma cholesterol.
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| 15. |
- Bacos, Karl, et al.
(författare)
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Islet beta-cell area and hormone expression are unaltered in Huntington's disease.
- 2008
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 1432-119X .- 0948-6143. ; 129, s. 623-629
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Tidskriftsartikel (refereegranskat)abstract
- Neurodegenerative disorders are often associated with metabolic alterations. This has received little attention, but might be clinically important because it can contribute to symptoms and influence the course of the disease. Patients with Huntington's disease (HD) exhibit increased incidence of diabetes mellitus (DM). This is replicated in mouse models of HD, e.g., the R6/2 mouse, in which DM is primarily caused by a deficiency of beta-cells with impaired insulin secretion. Pancreatic tissue from HD patients has previously not been studied and, thus, the pathogenesis of DM in HD is unclear. To address this issue, we examined pancreatic tissue sections from HD patients at different disease stages. We found that the pattern of insulin immunostaining, levels of insulin transcripts and islet beta-cell area were similar in HD patients and controls. Further, there was no sign of amyloid deposition in islets from HD patients. Thus, our data show that pancreatic islets in HD patients appear histologically normal. Functional studies of HD patients with respect to insulin secretion and islet function are required to elucidate the pathogenesis of DM in HD. This may lead to a better understanding of HD and provide novel therapeutic targets for symptomatic treatment in HD.
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| 16. |
- Bacos, Karl, et al.
(författare)
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Type 2 diabetes candidate genes, including PAX5, cause impaired insulin secretion in human pancreatic islets
- 2023
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Ingår i: The Journal of clinical investigation. - 0021-9738 .- 1558-8238. ; 133:4
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Tidskriftsartikel (refereegranskat)abstract
- Type 2 diabetes (T2D) is caused by insufficient insulin secretion from pancreatic β-cells. To identify candidates contributing to T2D pathophysiology, we studied human pancreatic islets from ~300 individuals. We found 395 differentially expressed genes (DEGs) in islets from individuals with T2D, including, to our knowledge, novel (OPRD1, PAX5, TET1) and previously identified (CHL1, GLRA1, IAPP) candidates. A third of the identified islet expression changes may predispose to diabetes, as they associated with HbA1c in individuals not previously diagnosed with T2D. Most DEGs were expressed in human β-cells based on single-cell RNA-sequencing data. Additionally, DEGs displayed alterations in open chromatin and associated with T2D-SNPs. Mouse knock-out strains demonstrated that T2D-associated candidates regulate glucose homeostasis and body composition in vivo. Functional validation showed that mimicking T2D-associated changes for OPRD1, PAX5, and SLC2A2 impaired insulin secretion. Impairments in Pax5-overexpressing β-cells were due to severe mitochondrial dysfunction. Finally, we discovered PAX5 as a potential transcriptional regulator of many T2D-associated DEGs in human islets. Overall, we identified molecular alterations in human pancreatic islets contributing to β-cell dysfunction in T2D pathophysiology.
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| 17. |
- Banke, Elin, et al.
(författare)
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Cocaine- and amphetamine-regulated transcript is expressed in adipocytes and regulate lipid- and glucose homeostasis.
- 2013
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Ingår i: Regulatory Peptides. - : Elsevier BV. - 1873-1686 .- 0167-0115. ; 182:Jan.,11, s. 35-40
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Tidskriftsartikel (refereegranskat)abstract
- Cocaine- and amphetamine-regulated transcript (CART) is a regulatory peptide expressed in the nervous system and in endocrine cells, e.g. in pancreatic islets. CART deficient mice exhibit islet dysfunction, impaired insulin secretion and increased body weight. A mutation in the CART gene in humans is associated with reduced metabolic rate, obesity and diabetes. Furthermore, CART is upregulated in islets of type-2 diabetic rats and regulates islet hormone secretion in vitro. While the function of CART in the nervous system has been extensively studied, there is no information on its expression or function in white adipose tissue. CART mRNA and protein were found to be expressed in both subcutaneous and visceral white adipose tissues from rat and man. Stimulating rat primary adipocytes with CART significantly potentiated isoprenaline-induced lipolysis, and hormone sensitive lipase activation (phosphorylation of Ser 563). On the other hand, CART significantly potentiated the inhibitory effect of insulin on isoprenaline-induced lipolysis. CART inhibited insulin-induced glucose uptake, which was associated with inhibition of PKB phosphorylation. In conclusion, CART is a novel constituent of human and rat adipocytes and affects several biological processes central in both lipid- and glucose homeostasis. Depending on the surrounding conditions, the effects of CART are insulin-like or insulin-antagonistic.
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| 18. |
- Bennet, Hedvig, et al.
(författare)
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Altered serotonin (5-HT) 1D and 2A receptor expression may contribute to defective insulin and glucagon secretion in human type 2 diabetes.
- 2015
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Ingår i: Peptides. - : Elsevier BV. - 1873-5169 .- 0196-9781. ; 71, s. 113-120
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Tidskriftsartikel (refereegranskat)abstract
- Islet produced 5-hydroxy tryptamine (5-HT) is suggested to regulate islet hormone secretion in a paracrine and autocrine manner in rodents. Hitherto, no studies demonstrate a role for this amine in human islet function, nor is it known if 5-HT signaling is involved in the development of beta cell dysfunction in type 2 diabetes (T2D). To clarify this, we performed a complete transcriptional mapping of 5-HT receptors and processing enzymes in human islets and investigated differential expression of these genes in non-diabetic and T2D human islet donors. We show the expression of fourteen 5-HT receptors as well as processing enzymes involved in the biosynthesis of 5-HT at the mRNA level in human islets. Two 5-HT receptors (HTR1D and HTR2A) were over-expressed in T2D islet donors. Both receptors (5-HT1d and 5-HT2a) were localized to human alpha, beta and delta cells. 5-HT inhibited both insulin and glucagon secretion in non-diabetic islet donors. In islets isolated from T2D donors the amine significantly increased release of insulin in response to glucose. Our results suggest that 5-HT signaling participates in regulation of overall islet hormone secretion in non- diabetic individuals and over-expression of HTR1D and HTR2A may either contribute to islet dysfunction in T2D or arise as a consequence of an already dysfunctional islet.
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| 19. |
- Bennet, Hedvig, et al.
(författare)
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Serotonin (5-HT) receptor 2b activation augments glucose-stimulated insulin secretion in human and mouse islets of Langerhans.
- 2016
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 59:4, s. 744-754
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Tidskriftsartikel (refereegranskat)abstract
- The Gq-coupled 5-hydroxytryptamine 2B (5-HT2B) receptor is known to regulate the proliferation of islet beta cells during pregnancy. However, the role of serotonin in the control of insulin release is still controversial. The aim of the present study was to explore the role of the 5-HT2B receptor in the regulation of insulin secretion in mouse and human islets, as well as in clonal INS-1(832/13) cells.
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| 20. |
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