Nitric oxide mediates the survival action of IGF-1 and insulin in pancreatic beta cells.
Generation of low levels of nitric oxide (NO) contributes to beta cell survival in vitro. The purpose of this study was to explore the link between NO and the survival pathway triggered by insulin-like growth factor-1 (IGF-1) and insulin in insulin producing RINm5F cells and in pancreatic islets. Results show that exposure of cells to IGF-1/insulin protects against serum deprivation-induced apoptosis. This action is prevented with inhibitors of NO generation, PI3K and Akt. Moreover, transfection with the negative dominant form of the tyrosine kinase c-Src abrogates the effect of IGF-1 and insulin on DNA fragmentation. An increase in the expression level of NOS3 protein and in the enzyme activity is observed following exposure of serum-deprived RINm5F cells to IGF-1 and insulin. Phosphorylation of IRS-1, IRS-2 and to less extent IRS-3 takes place when serum-deprived RINm5F cells and rat pancreatic islets are exposed to either IGF-1, insulin, or diethylenetriamine nitric oxide adduct (DETA/NO). In human islets, IRS-1 and IRS-2 proteins are present and tyrosine phosphorylated upon exposure to IGF-1, insulin and DETA/NO. Both rat and human pancreatic islets undergo DNA fragmentation when cultured in serum-free medium and IGF-1, insulin and DETA/NO protect efficiently from this damage. We then conclude that generation of NO participates in the activation of survival pathways by IGF-1 and insulin in beta cells.
Cahuana
Gladys M
GM
Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER)-University Pablo de Olavide, Sevilla, Spain.
Tejedo
Juan R
JR
Hmadcha
Abdelkrim
A
Ramírez
Remedios
R
Cuesta
Antonio L
AL
Soria
Bernat
B
Martin
Franz
F
Bedoya
Francisco J
FJ
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000328:Adult; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003671:DEET / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D055504:Insulin Receptor Substrate Proteins; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D050417:Insulin-Secreting Cells / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D009569:Nitric Oxide / Q000494:pharmacology*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D044967:Serum
D048868:Adaptor Proteins, Signal Transducing; C526297:IRS2 protein, human; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; C526299:Irs2 protein, rat; C491584:Irs3 protein, rat; D010750:Phosphoproteins; D003671:DEET; D009569:Nitric Oxide; D007334:Insulin-Like Growth Factor I; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D019869:Phosphatidylinositol 3-Kinases; D016392:Proto-Oncogene Proteins pp60(c-src); D051057:Proto-Oncogene Proteins c-akt