3-MST/H 2 S protects cerebral endothelial cells against OGD/R-induced injury via mitoprotection and inhibition of the RhoA/ROCK pathway.

3-mercaptopyruvate sulfurtransferase (3-MST) is the major source of hydrogen sulfide (H2 S) production in the brain and participates in many physiological and pathological processes. The present study was designed to investigate the role of 3-MST-derived H2 S (3-MST/H2 S) on oxygen-glucose deprivation/reoxygenation (OGD/R) injury in cerebrovascular endothelial cells (ECs). Using cerebrovascular specimens from patients with acute massive cerebral infarction (MCI), we found abnormal morphology of the endothelium and mitochondria, as well as decreases in H2 S and 3-MST levels. In an OGD/R model of ECs, 3-mercaptopyruvate (3-MP) and L-aspartic acid (L-Asp) were used to stimulate or inhibit the production of 3-MST/H2 S. The results showed that OGD/R induced significant decreases in H2 S and 3-MST levels in both ECs and mitochondria, as well as increases in oxidative stress and mitochondrial energy imbalance. Cellular oxidative stress, destruction of mitochondrial ultrastructure, accumulation of mitochondrial reactive oxygen species (ROS), reduction of mitochondrial adenosine triphosphate (ATP) synthase activity and ATP production, and decreased mitochondrial membrane potential were all significantly ameliorated by 3-MP, whereas they were exacerbated by L-Asp pretreatment. Contrary to the effects of L-Asp, the increase in RhoA activity and expression of ROCK1 and ROCK2 induced by OGD/R were markedly inhibited by 3-MP pretreatment in subcellular fractions without mitochondria and mitochondrial fractions. In addition, 3-MST-/- rat ECs displayed greater oxidative stress than 3-MST+/+ rat ECs after OGD/R injury.These findings suggest that 3-MST/H2 S protects ECs against OGD/R-induced injury, which may be related to preservation of mitochondrial function and inhibition of the RhoA/ROCK pathway.