1
|
Pelligra A, Mrugala J, Griess K, Kirschner P, Nortmann O, Bartosinska B, Köster A, Krupenko NI, Gebel D, Westhoff P, Steckel B, Eberhard D, Herebian D, Belgardt BF, Schrader J, Weber AP, Krupenko SA, Lammert E. Pancreatic islet protection at the expense of secretory function involves serine-linked mitochondrial one-carbon metabolism. Cell Rep 2023; 42:112703. [PMID: 37352100 PMCID: PMC10614219 DOI: 10.1016/j.celrep.2023.112703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2023] Open
|
2
|
Pelligra A, Mrugala J, Griess K, Kirschner P, Nortmann O, Bartosinska B, Köster A, Krupenko NI, Gebel D, Westhoff P, Steckel B, Eberhard D, Herebian D, Belgardt BF, Schrader J, Weber APM, Krupenko SA, Lammert E. Pancreatic islet protection at the expense of secretory function involves serine-linked mitochondrial one-carbon metabolism. Cell Rep 2023; 42:112615. [PMID: 37294632 PMCID: PMC10592470 DOI: 10.1016/j.celrep.2023.112615] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 03/30/2023] [Accepted: 05/23/2023] [Indexed: 06/11/2023] Open
Abstract
Type 2 diabetes is characterized by insulin hypersecretion followed by reduced glucose-stimulated insulin secretion (GSIS). Here we show that acute stimulation of pancreatic islets with the insulin secretagogue dextrorphan (DXO) or glibenclamide enhances GSIS, whereas chronic treatment with high concentrations of these drugs reduce GSIS but protect islets from cell death. Bulk RNA sequencing of islets shows increased expression of genes for serine-linked mitochondrial one-carbon metabolism (OCM) after chronic, but not acute, stimulation. In chronically stimulated islets, more glucose is metabolized to serine than to citrate, and the mitochondrial ATP/ADP ratio decreases, whereas the NADPH/NADP+ ratio increases. Activating transcription factor-4 (Atf4) is required and sufficient to activate serine-linked mitochondrial OCM genes in islets, with gain- and loss-of-function experiments showing that Atf4 reduces GSIS and is required, but not sufficient, for full DXO-mediated islet protection. In sum, we identify a reversible metabolic pathway that provides islet protection at the expense of secretory function.
Collapse
Affiliation(s)
- Angela Pelligra
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Jessica Mrugala
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany; Institute for Vascular and Islet Cell Biology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich Heine University, 40225 Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Kerstin Griess
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Philip Kirschner
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Oliver Nortmann
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Barbara Bartosinska
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Andrea Köster
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Natalia I Krupenko
- University of North Carolina (UNC) Nutrition Research Institute, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Dominik Gebel
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Philipp Westhoff
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Bodo Steckel
- Department of Molecular Cardiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Daniel Eberhard
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany; Institute for Vascular and Islet Cell Biology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Diran Herebian
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Bengt-Frederik Belgardt
- Institute for Vascular and Islet Cell Biology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich Heine University, 40225 Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Jürgen Schrader
- Department of Molecular Cardiology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Sergey A Krupenko
- University of North Carolina (UNC) Nutrition Research Institute, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Eckhard Lammert
- Institute of Metabolic Physiology, Heinrich Heine University, 40225 Düsseldorf, Germany; Institute for Vascular and Islet Cell Biology, German Diabetes Center (DDZ), Leibniz Center for Diabetes Research at Heinrich Heine University, 40225 Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), Helmholtz Zentrum München, 85764 Neuherberg, Germany.
| |
Collapse
|
3
|
Janssen AWF, Katiraei S, Bartosinska B, Eberhard D, Willems van Dijk K, Kersten S. Loss of angiopoietin-like 4 (ANGPTL4) in mice with diet-induced obesity uncouples visceral obesity from glucose intolerance partly via the gut microbiota. Diabetologia 2018; 61:1447-1458. [PMID: 29502266 PMCID: PMC6449003 DOI: 10.1007/s00125-018-4583-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 01/22/2018] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Angiopoietin-like 4 (ANGPTL4) is an important regulator of triacylglycerol metabolism, carrying out this role by inhibiting the enzymes lipoprotein lipase and pancreatic lipase. ANGPTL4 is a potential target for ameliorating cardiometabolic diseases. Although ANGPTL4 has been implicated in obesity, the study of the direct role of ANGPTL4 in diet-induced obesity and related metabolic dysfunction is hampered by the massive acute-phase response and development of lethal chylous ascites and peritonitis in Angptl4-/- mice fed a standard high-fat diet. The aim of this study was to better characterise the role of ANGPTL4 in glucose homeostasis and metabolic dysfunction during obesity. METHODS We chronically fed wild-type (WT) and Angptl4-/- mice a diet rich in unsaturated fatty acids and cholesterol, combined with fructose in drinking water, and studied metabolic function. The role of the gut microbiota was investigated by orally administering a mixture of antibiotics (ampicillin, neomycin, metronidazole). Glucose homeostasis was assessed via i.p. glucose and insulin tolerance tests. RESULTS Mice lacking ANGPTL4 displayed an increase in body weight gain, visceral adipose tissue mass, visceral adipose tissue lipoprotein lipase activity and visceral adipose tissue inflammation compared with WT mice. However, they also unexpectedly had markedly improved glucose tolerance, which was accompanied by elevated insulin levels. Loss of ANGPTL4 did not affect glucose-stimulated insulin secretion in isolated pancreatic islets. Since the gut microbiota have been suggested to influence insulin secretion, and because ANGPTL4 has been proposed to link the gut microbiota to host metabolism, we hypothesised a potential role of the gut microbiota. Gut microbiota composition was significantly different between Angptl4-/- mice and WT mice. Interestingly, suppression of the gut microbiota using antibiotics largely abolished the differences in glucose tolerance and insulin levels between WT and Angptl4-/- mice. CONCLUSIONS/INTERPRETATION Despite increasing visceral fat mass, inactivation of ANGPTL4 improves glucose tolerance, at least partly via a gut microbiota-dependent mechanism.
Collapse
Affiliation(s)
- Aafke W F Janssen
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, the Netherlands
| | - Saeed Katiraei
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Barbara Bartosinska
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München Neuherberg, Germany
| | - Daniel Eberhard
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München Neuherberg, Germany
| | - Ko Willems van Dijk
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
- Division of Endocrinology, Department of Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, the Netherlands.
| |
Collapse
|
4
|
Kragl M, Schubert R, Karsjens H, Otter S, Bartosinska B, Jeruschke K, Weiss J, Chen C, Alsteens D, Kuss O, Speier S, Eberhard D, Müller DJ, Lammert E. The biomechanical properties of an epithelial tissue determine the location of its vasculature. Nat Commun 2016; 7:13560. [PMID: 27995929 PMCID: PMC5187430 DOI: 10.1038/ncomms13560] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 10/14/2016] [Indexed: 01/06/2023] Open
Abstract
An important question is how growing tissues establish a blood vessel network. Here we study vascular network formation in pancreatic islets, endocrine tissues derived from pancreatic epithelium. We find that depletion of integrin-linked kinase (ILK) in the pancreatic epithelial cells of mice results in glucose intolerance due to a loss of the intra-islet vasculature. In turn, blood vessels accumulate at the islet periphery. Neither alterations in endothelial cell proliferation, apoptosis, morphology, Vegfa expression and VEGF-A secretion nor ‘empty sleeves' of vascular basement membrane are found. Instead, biophysical experiments reveal that the biomechanical properties of pancreatic islet cells, such as their actomyosin-mediated cortex tension and adhesive forces to endothelial cells, are significantly changed. These results suggest that a sorting event is driving the segregation of endothelial and epithelial cells and indicate that the epithelial biomechanical properties determine whether the blood vasculature invades or envelops a growing epithelial tissue. Vasculature is denser in soft than in stiff tissues. Kragl et al. suggest a mechanistic link between biomechanical tissue properties and vascularization by showing that integrin-linked kinase reduces the contractile forces of the cell cortex in endocrine pancreatic cells, facilitating their adhesion to blood vessels and enabling pancreatic islet vascularization.
Collapse
Affiliation(s)
- Martin Kragl
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, D-40225 Düsseldorf, Germany.,German Center for Diabetes Research (DZD e.V.), D-85764 München-Neuherberg, Germany.,Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Rajib Schubert
- Eidgenössische Technische Hochschule Zürich, Department of Biosystems Science and Engineering, CH-4058 Basel, Switzerland
| | - Haiko Karsjens
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, D-40225 Düsseldorf, Germany.,German Center for Diabetes Research (DZD e.V.), D-85764 München-Neuherberg, Germany.,Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Silke Otter
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Barbara Bartosinska
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, D-40225 Düsseldorf, Germany.,German Center for Diabetes Research (DZD e.V.), D-85764 München-Neuherberg, Germany.,Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Kay Jeruschke
- German Center for Diabetes Research (DZD e.V.), D-85764 München-Neuherberg, Germany.,Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Jürgen Weiss
- German Center for Diabetes Research (DZD e.V.), D-85764 München-Neuherberg, Germany.,Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Chunguang Chen
- German Center for Diabetes Research (DZD e.V.), D-85764 München-Neuherberg, Germany.,Paul Langerhans Institute Dresden (PLID) of Helmholtz Center Munich at the University Clinic Carl Gustav Carus of Technische Universität Dresden, Helmholtz Zentrum München, D-85764 Neuherberg, Germany.,DFG-Center for Regenerative Therapies Dresden (CRTD), Faculty of Medicine, Technische Universität Dresden, D-01307 Dresden, Germany
| | - David Alsteens
- Eidgenössische Technische Hochschule Zürich, Department of Biosystems Science and Engineering, CH-4058 Basel, Switzerland
| | - Oliver Kuss
- German Center for Diabetes Research (DZD e.V.), D-85764 München-Neuherberg, Germany.,Institute for Biometrics and Epidemiology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Stephan Speier
- German Center for Diabetes Research (DZD e.V.), D-85764 München-Neuherberg, Germany.,Paul Langerhans Institute Dresden (PLID) of Helmholtz Center Munich at the University Clinic Carl Gustav Carus of Technische Universität Dresden, Helmholtz Zentrum München, D-85764 Neuherberg, Germany.,DFG-Center for Regenerative Therapies Dresden (CRTD), Faculty of Medicine, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Daniel Eberhard
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, D-40225 Düsseldorf, Germany
| | - Daniel J Müller
- Eidgenössische Technische Hochschule Zürich, Department of Biosystems Science and Engineering, CH-4058 Basel, Switzerland
| | - Eckhard Lammert
- Institute of Metabolic Physiology, Department of Biology, Heinrich Heine University, D-40225 Düsseldorf, Germany.,German Center for Diabetes Research (DZD e.V.), D-85764 München-Neuherberg, Germany.,Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, D-40225 Düsseldorf, Germany
| |
Collapse
|
5
|
Jain D, Weber G, Eberhard D, Mehana AE, Eglinger J, Welters A, Bartosinska B, Jeruschke K, Weiss J, Päth G, Ariga H, Seufert J, Lammert E. DJ-1 Protects Pancreatic Beta Cells from Cytokine- and Streptozotocin-Mediated Cell Death. PLoS One 2015; 10:e0138535. [PMID: 26422139 PMCID: PMC4589499 DOI: 10.1371/journal.pone.0138535] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/01/2015] [Indexed: 01/07/2023] Open
Abstract
A hallmark feature of type 1 and type 2 diabetes mellitus is the progressive dysfunction and loss of insulin-producing pancreatic beta cells, and inflammatory cytokines are known to trigger beta cell death. Here we asked whether the anti-oxidant protein DJ-1 encoded by the Parkinson’s disease gene PARK7 protects islet cells from cytokine- and streptozotocin-mediated cell death. Wild type and DJ-1 knockout mice (KO) were treated with multiple low doses of streptozotocin (MLDS) to induce inflammatory beta cell stress and cell death. Subsequently, glucose tolerance tests were performed, and plasma insulin as well as fasting and random blood glucose concentrations were monitored. Mitochondrial morphology and number of insulin granules were quantified in beta cells. Moreover, islet cell damage was determined in vitro after streptozotocin and cytokine treatment of isolated wild type and DJ-1 KO islets using calcein AM/ethidium homodimer-1 staining and TUNEL staining. Compared to wild type mice, DJ-1 KO mice became diabetic following MLDS treatment. Insulin concentrations were substantially reduced, and fasting blood glucose concentrations were significantly higher in MLDS-treated DJ-1 KO mice compared to equally treated wild type mice. Rates of beta cell apoptosis upon MLDS treatment were twofold higher in DJ-1 KO mice compared to wild type mice, and in vitro inflammatory cytokines led to twice as much beta cell death in pancreatic islets from DJ-1 KO mice versus those of wild type mice. In conclusion, this study identified the anti-oxidant protein DJ-1 as being capable of protecting pancreatic islet cells from cell death induced by an inflammatory and cytotoxic setting.
Collapse
Affiliation(s)
- Deepak Jain
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany
- Institute for Beta Cell Biology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Düsseldorf Partner Institute, Düsseldorf, Germany
| | - Gesine Weber
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany
| | - Daniel Eberhard
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany
- Institute for Beta Cell Biology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
| | - Amir E. Mehana
- Division of Endocrinology and Diabetology, Department of Internal Medicine II, University Hospital of Freiburg, Freiburg, Germany
- Department of Zoology, Faculty of Science, Suez Canal University, Ismailia, Egypt
| | - Jan Eglinger
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany
- Institute for Beta Cell Biology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Düsseldorf Partner Institute, Düsseldorf, Germany
| | - Alena Welters
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany
- Institute for Beta Cell Biology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Düsseldorf Partner Institute, Düsseldorf, Germany
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children’s Hospital Düsseldorf, Düsseldorf, Germany
| | - Barbara Bartosinska
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany
| | - Kay Jeruschke
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
| | - Jürgen Weiss
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
| | - Günter Päth
- Division of Endocrinology and Diabetology, Department of Internal Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Hiroyoshi Ariga
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-Ku, N12 W6, Sapporo, Japan
| | - Jochen Seufert
- Division of Endocrinology and Diabetology, Department of Internal Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Eckhard Lammert
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany
- Institute for Beta Cell Biology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Düsseldorf Partner Institute, Düsseldorf, Germany
- * E-mail:
| |
Collapse
|
6
|
Jain R, Jain D, Liu Q, Bartosinska B, Wang J, Schumann D, Kauschke SG, Eickelmann P, Piemonti L, Gray NS, Lammert E. Pharmacological inhibition of Eph receptors enhances glucose-stimulated insulin secretion from mouse and human pancreatic islets. Diabetologia 2013; 56:1350-5. [PMID: 23475368 DOI: 10.1007/s00125-013-2877-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 02/07/2013] [Indexed: 12/22/2022]
Abstract
AIMS/HYPOTHESIS Type 2 diabetes is characterised by impaired glucose-stimulated insulin secretion (GSIS) from pancreatic islets. Since erythropoietin-producing hepatoma (Eph)-ephrin bidirectional signalling fine-tunes GSIS from pancreatic beta cells, we investigated Eph receptor tyrosine kinases (RTK) as potential drug targets for selectively increasing GSIS. METHODS Insulin secretion assays were carried out using mouse and human pancreatic islets as well as mouse insulinoma (MIN6) cells in the presence or absence of two Eph RTK inhibitors. Furthermore, the most potent inhibitor was injected into mice to evaluate its effects on glucose tolerance and plasma insulin levels. RESULTS We showed that the Eph RTK inhibitors selectively increased GSIS from MIN6 cells as well as mouse and human islets. Our results also showed that the insulin secretory effects of these compounds required Eph-ephrin signalling. Finally, pharmacological inhibition of Eph receptor signalling improved glucose tolerance in mice. CONCLUSIONS/INTERPRETATION We showed for the first time that Eph RTKs represent targets for small molecules to selectively increase GSIS and improve glucose tolerance.
Collapse
Affiliation(s)
- R Jain
- Institute of Metabolic Physiology and German Diabetes Center, Heinrich-Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|