Acetylcholine promotes ROS detoxification against hypoxia/reoxygenation-induced oxidative stress through FoxO3a/PGC-1α dependent superoxide dismutase

Abstract

Background/Aims: Acetylcholine (ACh) is known to modulate the cardiac redox environment and thereby suppress reactive oxygen species (ROS) generation during oxidative stress. However, there is little information about its regulation on ROS clearance. Here we investigate the beneficial effects of ACh on superoxide dismutase (SOD) as key ROS-detoxifying enzyme system in cultured rat cardiomyoblasts. Methods: H9c2 cells were subjected to hypoxia/reoxygenation (H/R) to mimic oxidative stress. Western blot was used to detect the expression of SOD and related signaling molecules. Specific protein knockdown was performed with siRNA transfection. Results: ACh treatment on the beginning of reoxygenation decreased ROS and apoptosis. ACh increased ATP synthesis and mitochondrial DNA. Furthermore, ACh significantly reversed H/R-induced reduction in protein expressions and activities of SOD. ACh stimulated peroxisome proliferator activated receptor γ co-activator la (PGC-lα) and decreased forkhead box subfamily O3a (FoxO3a) phosphorylation. Atropine (muscarinic receptor antagonist) abolished the cytoprotection afforded by ACh. PGC-la siRNA blocked ACh-induced invigorating effects on SOD2, whereas it did not alter SOD1 and FoxO3a phosphorylation. FoxO3a siRNA drastically decreased the expressions of S0D2 and PGC-la, while it did not affect SOD1. Conclusion: ACh activates SOD2 within mitochondria through Fox03a/PGC-la pathway and up-regulates S0D1 in the cytoplasm, thus protecting against oxidative injury induced by H/R. Ourfindings provide newinsights into mechanisms underlying the cardioprotection of ACh on ROS detoxifying.