Hydrogen sulfide is an endogenous stimulator of angiogenesis

Abstract

The goal of the current study was to investigate the role of exogenous and endogenous hydrogen sulfide (H 2 S) on neovascularization and wound healing in vitro and in vivo. Incubation of endothelial cells (ECs) with H 2 S enhanced their angiogenic potential, evidenced by accelerated cell growth, migration, and capillary morphogenesis on Matrigel. Treatment of chicken chorioallantoic membranes (CAMS) with H 2 S increased vascular length. Exposure of ECs to H 2 S resulted in increased phosphorylation of Akt, ERK, and p38. The K ATP channel blocker glibenclamide or the p38 inhibitor SB203580 abolished H 2 S-induced EC motility. Since glibenclamide inhibited H 2 S-triggered p38 phosphorylation, we propose that K ATP channels lay upstream of p38 in this process. When CAMs were treated with H 2 S biosynthesis inhibitors dl-propylargylglycine or beta-cyano-L-alanine, a reduction in vessel length and branching was observed, indicating that H 2 S serves as an endogenous stimulator of the angiogenic response. Stimulation of ECs with vascular endothelial growth factor (VEGF) increased H 2 S release, while pharmacological inhibition of H 2 S production or K ATP channels or silencing of cystathionine gamma-lyase (CSE) attenuated VEGF signaling and migration of ECs. These results implicate endothelial H 2 S synthesis in the pro-angiogenic action of VEGF. Aortic rings isolated from CSE knockout mice exhibited markedly reduced microvessel formation in response to VEGF when compared to wild-type littermates. Finally, in vivo, topical administration of H 2 S enhanced wound healing in a rat model, while wound healing was delayed in CSE −/− mice. We conclude that endogenous and exogenous H 2 S stimulates EC-related angiogenic properties through a K ATP channel/MAPK pathway.