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- Amisten, Stefan, et al.
(författare)
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A comparative analysis of human and mouse islet G-protein coupled receptor expression
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- G-protein coupled receptors (GPCRs) are essential for islet function, but most studies use rodent islets due to limited human islet availability. We have systematically compared the GPCR mRNA expression in human and mouse islets to determine to what extent mouse islets can be used as surrogates for human islets to study islet GPCR function, and we have identified species-specific expression of several GPCRs. The A 3 receptor (ADORA3) was expressed only in mouse islets and the A 3 agonist MRS 5698 inhibited glucose-induced insulin secretion from mouse islets, with no effect on human islets. Similarly, mRNAs encoding the galanin receptors GAL 1 (GALR1), GAL 2 (GALR2) and GAL 3 GALR3) were abundantly expressed in mouse islets but present only at low levels in human islets, so that it reads (GALR3) and galanin inhibited insulin secretion only from mouse islets. Conversely, the sst1 receptor (SSTR1) was abundant only in human islets and its selective activation by CH 275 inhibited insulin secretion from human islets, with no effect on mouse islets. Our comprehensive human and mouse islet GPCR atlas has demonstrated that species differences do exist in islet GPCR expression and function, which are likely to impact on the translatability of mouse studies to the human context.
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| 5. |
- Amisten, Stefan, et al.
(författare)
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ADP mediates inhibition of insulin secretion by activation of P2Y13 receptors in mice.
- 2010
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; Jul 1, s. 1927-1934
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Tidskriftsartikel (refereegranskat)abstract
- AIMS/HYPOTHESES: To investigate the effects of extracellular purines on insulin secretion from mouse pancreatic islets. METHODS: Mouse islets and beta cells were isolated and examined with mRNA real-time quantification, cAMP quantification and insulin and glucagon secretion. ATP release was measured in MIN6c4 cells. Insulin and glucagon secretion were measured in vivo after glucose injection. RESULTS: Enzymatic removal of extracellular ATP at low glucose levels increased the secretion of both insulin and glucagon, while at high glucose levels insulin secretion was reduced and glucagon secretion was stimulated, indicating an autocrine effect of purines. In MIN6c4 cells it was shown that glucose does induce release of ATP into the extracellular space. Quantitative real-time PCR demonstrated the expression of the ADP receptors P2Y(1) and P2Y(13) in both intact mouse pancreatic islets and isolated beta cells. The stable ADP analogue 2-MeSADP had no effect on insulin secretion. However, co-incubation with the P2Y(1) antagonist MRS2179 inhibited insulin secretion, while co-incubation with the P2Y(13) antagonist MRS2211 stimulated insulin secretion, indicating that ADP acting via P2Y(1) stimulates insulin secretion, while signalling via P2Y(13) inhibits the secretion of insulin. P2Y(13) antagonism through MRS2211 per se increased the secretion of both insulin and glucagon at intermediate (8.3 mmol/l) and high (20 mmol/l) glucose levels, confirming an autocrine role for ADP. Administration of MRS2211 during glucose injection in vivo resulted in both increased secretion of insulin and reduced glucose levels. CONCLUSIONS/INTERPRETATION: In conclusion, ADP acting on the P2Y(13) receptors inhibits insulin release. An antagonist to P2Y(13) increases insulin release and could be evaluated for the treatment of diabetes.
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| 6. |
- Amisten, Stefan, et al.
(författare)
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An atlas and functional analysis of G-protein coupled receptors in human islets of Langerhans
- 2013
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Ingår i: Pharmacology and Therapeutics. - : Elsevier BV. - 0163-7258. ; 139:3, s. 359-391
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Forskningsöversikt (refereegranskat)abstract
- G-protein coupled receptors (GPCRs) regulate hormone secretion from islets of Langerhans, and recently developed therapies for type-2 diabetes target islet GLP-1 receptors. However, the total number of GPCRs expressed by human islets, as well as their function and interactions with drugs, is poorly understood. In this review we have constructed an atlas of all GPCRs expressed by human islets: the 'islet GPCRome'. We have used this atlas to describe how islet GPCRs interact with their endogenous ligands, regulate islet hormone secretion, and interact with drugs known to target GPCRs, with a focus on drug/receptor interactions that may affect insulin secretion. The islet GPCRome consists of 293 GPCRs, a majority of which have unknown effects on insulin, glucagon and somatostatin secretion. The islet GPCRs are activated by 271 different endogenous ligands, at least 131 of which are present in islet cells. A large signalling redundancy was also found, with 119 ligands activating more than one islet receptor. Islet GPCRs are also the targets of a large number of clinically used drugs, and based on their coupling characteristics and effects on receptor signalling we identified 107 drugs predicted to stimulate and 184 drugs predicted to inhibit insulin secretion. The islet GPCRome highlights knowledge gaps in the current understanding of islet GPCR function, and identifies GPCR/ligand/drug interactions that might affect insulin secretion, which are important for understanding the metabolic side effects of drugs. This approach may aid in the design of new safer therapeutic agents with fewer detrimental effects on islet hormone secretion. (C) 2013 Elsevier Inc. All rights reserved.
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| 7. |
- Amisten, Stefan, et al.
(författare)
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An atlas of G-protein coupled receptor expression and function in human subcutaneous adipose tissue.
- 2015
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Ingår i: Pharmacology and Therapeutics. - : Elsevier BV. - 0163-7258. ; 146:Sep 19, s. 61-93
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Forskningsöversikt (refereegranskat)abstract
- G-protein coupled receptors (GPCRs) are involved in the regulation of adipose tissue function, but the total number of GPCRs expressed by human subcutaneous adipose tissue, as well as their function and interactions with drugs, is poorly understood. We have constructed an atlas of all GPCRs expressed by human subcutaneous adipose tissue: the 'adipose tissue GPCRome', to support the exploration of novel control nodes in metabolic and endocrine functions. This atlas describes how adipose tissue GPCRs regulate lipolysis, insulin resistance and adiponectin and leptin secretion. We also discuss how adipose tissue GPCRs interact with their endogenous ligands and with GPCR-targeting drugs, with a focus on how drug/receptor interactions may affect lipolysis, and present a model predicting how GPCRs with unknown effects on lipolysis might modulate cAMP-regulated lipolysis. Subcutaneous adipose tissue expresses 163 GPCRs, a majority of which have unknown effects on lipolysis, insulin resistance and adiponectin and leptin secretion. These GPCRs are activated by 180 different endogenous ligands, and are the targets of a large number of clinically used drugs. We identified 119 drugs, acting on 23 GPCRs, that are predicted to stimulate lipolysis and 173 drugs, acting on 25 GPCRs, that are predicted to inhibit lipolysis. This atlas highlights knowledge gaps in the current understanding of adipose tissue GPCR function, and identifies GPCR/ligand/drug interactions that might affect lipolysis, which is important for understanding and predicting metabolic side effects of drugs. This approach may aid in the design of new, safer therapeutic agents, with fewer undesired effects on lipid homeostasis.
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| 8. |
- Amisten, Stefan, et al.
(författare)
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Anti-diabetic action of all- trans retinoic acid and the orphan G protein coupled receptor GPRC5C in pancreatic beta-cells
- 2017
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Ingår i: Endocrine Journal. - 0918-8959. ; 64:3, s. 325-338
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Tidskriftsartikel (refereegranskat)abstract
- Pancreatic islets express high levels of the orphan G-protein coupled receptor C5C (GPRC5C), the function of which remains to be established. Here we have examined the role of GPRC5C in the regulation of insulin secretion and beta-cell survival and proliferation using human and mouse pancreatic islets. The expression of GPRC5C was analysed by RNA-sequencing, qPCR, western blotting and confocal microscopy. Insulin secretion and cell viability were determined by RIA and MTS assays, respectively. GPRC5C mRNA expression and protein level were reduced in the islets from type-2 diabetic donors. RNA sequencing in human islets revealed GPRC5C expression correlated with the expression of genes controlling apoptosis, cell survival and proliferation. A reduction in Gprc5c mRNA and protein expression was observed in islets isolated from old mice (>46 weeks of age) compared to that in islets from newborn (<3 weeks) mice. Down-regulation of Gprc5c led to both moderately reduced glucose-stimulated insulin release and also reduced cAMP content in mouse islets. Potentiation of glucose-stimulated insulin secretion concomitant with enhanced islet cAMP level by all-trans retinoic acid (ATRA) was attenuated upon Gprc5c-KD. ATRA also increased [Ca+2](i) in Huh7-cells. Gprc5c over expression in Huh7 cells was associated with increased ERK1/2 activity. Gprc5c-KD in clonal MIN6c4 cells reduced cell proliferation and in murine islets increased apoptosis and the sensitivity of primary islet cells to a cocktail of pro-apoptotic cytokines. Our results demonstrate that agents activating GPRC5C represent a novel modality for the treatment and/or prevention of diabetes by restoring and/or maintaining functional beta-cell mass.
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| 9. |
- Balhuizen, Alexander, et al.
(författare)
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Activation of G protein-coupled receptor 30 modulates hormone secretion and counteracts cytokine-induced apoptosis in pancreatic islets of female mice.
- 2010
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 1872-8057 .- 0303-7207. ; 320, s. 16-24
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Tidskriftsartikel (refereegranskat)abstract
- The role of the newly discovered estrogen receptor GPR30 in islet physiology and pathophysiology is unclear. We examined GPR30 expression in relation to hormone secretion and possible anti-apoptotic effects in isolated mouse islets using the synthetic GPR30 ligand G-1. The mRNA and protein expression of GPR30 was analyzed by qPCR, Western blot and confocal microscopy. Hormone secretion and cAMP content were determined with RIA and apoptosis in islet cells with the Annexin-V method. GPR30 mRNA and protein expression was markedly higher in islets from females compared to male. This gender difference was not found for the genomic estrogen receptors ERalpha and ERbeta, the ERalpha expression being 10-fold higher than ERbeta in both genders. Confocal microscopy revealed abounden GPR30 expression in insulin, glucagon and somatostatin cells. Dose-response studies of G-1 vs 17beta-estradiol in isolated islets at 1 or 12mM glucose showed an almost identical pattern in that both compounds increased insulin and inhibited glucagon and somatostatin secretion. ICI-182,780 and EM-652, potent antagonists of the 17beta-estradiol receptors (ERalpha and ERbeta) did not influence the amplifying effect of G-1 or 17beta-estradiol on cAMP content or insulin secretion from isolated islets. Cytokine-induced (IL-1beta+TNFalpha+INFgamma) apoptosis in islets, cultured for 24h at 5mM glucose, was almost abolished by G-1 or 17beta-estradiol treatment. Addition of ICI-182,780 or EM-652 did not affect this beneficial effect of G-1 or 17beta-estradiol. Taken together, our findings show that GPR30 is expressed in most islet endocrine cells. The synthetic GPR30 ligand G-1 mimics the non-genomic effects of 17beta-estradiol on islet hormone secretion, cAMP content in islets and its anti-apoptotic effects. G-1 or analogs thereof might be new potential candidates in the therapeutic strategy for type 2 diabetes in women.
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