S-propranolol protected H9C2 cells from ischemia/reperfusion-induced apoptosis via downregultion of RACK1 Gene.

Ischemia-reperfusion (I/R) injury can lead to apoptotic death of heart cells and subsequently heart failure. Propranolol is widely used in the management of cardiovascular disorders, but the mechanism is still unclear. Our previous studies showed that activated protein kinase C1 (RACK1) was significantly down-regulated in human umbilical vein endothelial cells by S-propranolol. RACK1 may be a target protein of S-propranolol during I/R. At present, we constructed a lentiviral expression vector for RNA interference (RNAi) of RACK1. The interference efficiency of the lentivirus was confirmed by RT-PCR and western blot. H9C2 cells infected with Lv-RACK1-shRNA or control were subjected to simulate I/R in the presence and absence of S-propranolol. The release of cytokines and chemokines was determined by ELISA assay. Flow cytometry was employed to determine mitochondrial membrane potential (MMP), Ca(2+) concentration, reactive oxygen species (ROS) production, and cell apoptosis. We found that RACK1 RNAi and S-propranolol treatment remarkably protected I/R injured cells from apoptosis via attenuating the release of cytokines and chemokines, Ca(2+) overload, ROS concentration, and MMP. Furthermore, RACK1 RNAi and S-propranolol, separately and in combination, significantly reduced caspase-3 activity, cytochrome c release and JNK activation. RACK 1 can be considered as a target for drug development.