The Pathogenic Role of Cystathionine γ-Lyase/Hydrogen Sulfide in Streptozotocin-Induced Diabetes in Mice

Reduced β-cell mass and increased activities of ATP-sensitive K+ channels in pancreatic β cells are associated with the pathogenesis of diabetes. Cystathionine γ-lyase (CSE) is a major hydrogen sulfide (H2S)-producing enzyme in pancreatic β cells. Herein, we examine the effects of genetic and pharmacologic ablation of CSE on β-cell functions and their correlation with streptozotocin (STZ)-induced diabetes. Compared with wild-type mice, CSE knockout (CSE KO) mice that received STZ injections exhibited a delayed onset of diabetic status. The application of dl-propargylglycine (PPG) to inhibit CSE activity protected wild-type mice from STZ-induced hyperglycemia and hypoinsulinemia. STZ significantly increased pancreatic H2S production in wild-type mice but not in CSE KO mice. STZ induced more apoptotic β-cell death in wild-type mice than in CSE KO mice. STZ exposure decreased the viability of cultured INS-1E cells, which was partly reversed by PPG co-treatment. STZ also significantly stimulated H2S production in cultured INS-1E cells. In addition, STZ stimulated ATP-sensitive K+ currents in pancreatic β cells from wild-type mice but not in the presence of PPG or in β cells from CSE KO mice. Sodium hydrosulfide injection instantly increased blood glucose, decreased plasma insulin, and deteriorated glucose tolerance in mice. Take together, these results provide evidence that the CSE/H2S system plays a critical role in regulating β-cell functions.