title: High glucose and free fatty acids induce beta cell apoptosis via autocrine effects of ADP acting on the P2Y(13) receptor.
abstract: While high levels of glucose and saturated fatty acids are known to have detrimental effects on beta cell function and survival, the signalling pathways mediating these effects are not entirely known. In a previous study, we found that ADP regulates beta cell insulin secretion and beta cell apoptosis. Using MIN6c4 cells as a model system, we investigated if autocrine/paracrine mechanisms of ADP and purinergic receptors are involved in this process. High glucose (16.7 mmol/l) and palmitate (100 μmol/l) rapidly and potently elevated the extracellular ATP levels, while mannitol was without effect. Both tolbutamide and diazoxide were without effect, while the calcium channel blocker nifedipine, the volume-regulated anion channels (VRAC) inhibitor NPPB, and the pannexin inhibitor carbenoxolone could inhibit both effects. Similarly, silencing the MDR1 gene also blocked nutrient-generated ATP release. These results indicate that calcium channels and VRAC might be involved in the ATP release mechanism. Furthermore, high glucose and palmitate inhibited cAMP production, reduced cell proliferation in MIN6c4 and increased activated Caspase-3 cells in mouse islets and in MIN6c4 cells. The P2Y(13)-specific antagonist MRS2211 antagonized all these effects. Further studies showed that blocking the P2Y(13) receptor resulted in enhanced CREB, Bad and IRS-1 phosphorylation, which are known to be involved in beta cell survival and insulin secretion. These findings provide further support for the concept that P2Y(13) plays an important role in beta cell apoptosis and suggest that autocrine/paracrine mechanisms, related to ADP and P2Y(13) receptors, contribute to glucolipotoxicity.
authors.affiliation: Department of Cardiology, Lund University, 22185, Lund, Sweden.
authors.forename: Chanyuan
authors.initials: C
authors.lastname: Tan
authors.forename: Ulrikke
authors.initials: U
authors.lastname: Voss
authors.forename: Siv
authors.initials: S
authors.lastname: Svensson
authors.forename: David
authors.initials: D
authors.lastname: Erlinge
authors.forename: Björn
authors.initials: B
authors.lastname: Olde
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D019898:Autocrine Communication / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D002469:Cell Separation; D005230:Fatty Acids, Nonesterified / Q000494:pharmacology*; D005260:Female; D005947:Glucose / Q000494:pharmacology*; D007150:Immunohistochemistry; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects*; D016086:Lentivirus / Q000235:genetics; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D018048:Receptors, Purinergic P2 / Q000187:drug effects*; D014161:Transduction, Genetic
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D005230:Fatty Acids, Nonesterified; D007328:Insulin; C486689:P2ry13 protein, mouse; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D008156:Luciferases; D053148:Caspase 3; D005947:Glucose