Acetylcholine Promotes ROS Detoxification Against Hypoxia/reoxygenation-Induced Oxidative Stress Through FoxO3a/PGC-1a 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 1α (PGC-1α) and decreased forkhead box subfamily O3a (FoxO3a) phosphorylation. Atropine (muscarinic receptor antagonist) abolished the cytoprotection afforded by ACh. PGC-1α siRNA blocked ACh-induced invigorating effects on SOD2, whereas it did not alter SOD1 and FoxO3a phosphorylation. FoxOSa siRNA drastically decreased the expressions of SOD2 and PGC-1α, while it did not affect SOD1. Conclusion: ACh activates SOD2 within mitochondria through FoxO3a/PGC-1α pathway and up-regulates SOD1 in the cytoplasm, thus protecting against oxidative injury induced by H/R. Our findings provide new insights into mechanisms underlying the cardioprotection of ACh on ROS detoxifying. © 2014 S. Karger AG, Basel

Acetylcholine ameliorates endoplasmic reticulum stress in endothelial cells after hypoxia/reoxygenation via M3 AChR-AMPK signaling

“…45 Previous studies in our lab have shown that ACh benefits to the heart and endothelium by acting on M AChR. [14][15][16]46 M3 AChR siRNA as well as 4-DAMP, significantly abolished the protective effect elicited by ACh, suggesting that the action of ACh on ER stress was mediated mainly by M3 AChR. Intriguingly, our results also showed that M3 AChR siRNA abolished ACh-elicited restoration of AMPK during H/R.…”

“…The endothelial cells were subjected to hypoxia for 8 h to induce simulated ischemia as previously described. 46 For reoxygenation, the medium was replaced with fresh serum-free F12K medium and rapidly transferred into a normoxic incubator (5% CO 2 and 95% air) for 16 h. Then the cells were divided randomly into the following groups for treatment: (1) Con: culture normally with F12K; (2) ACh: administration of ACh (10 ¡6 M) alone; (3) H/R: 8 h of hypoxia followed by reoxygenation for 16 h; (4) H/R C 4-PBA: 4-PBA (10 ¡4 M) was added at the onset of reoxygenation; (5) H/R C 4-DAMP C ACh: M3 AChR inhibitor 4-DAMP (10 ¡6 M) was used in combination with ACh (10 ¡6 M) at the onset of reoxygenation. These agents were all purchased from Sigma.…”

Resistin Regulates Fatty Acid Β Oxidation by Suppressing Expression of Peroxisome Proliferator Activator Receptor Gamma-Coactivator 1α (PGC-1α)

“…Our study showed that resistin can inhibit lipid β oxidation and explored a potential mechanism by which resistin regulates lipid metabolism. The increase of PGC-1α activity has been considered as a valid therapeutic target in the amelioration of several metabolic diseases [17]. Moreover, in vivo studies have shown that specific overexpression of PGC-1α in skeletal muscle tissue provides strong beneficial effects and protects against age-associated diseases [18].…”

The Role of PGC-1α in the Development of Insulin Resistance in Skeletal Muscle - Revisited

“…Both these aforementioned processes are tightly regulated by a set of nuclear receptors called peroxisome proliferator-activated receptors (PPARs) [9,10]. PPARγ coactivator 1-α (PGC-1α) is one of the best characterized regulatory proteins, and it interacts with numerous nuclear receptors (including PPARs) and regulates various aspects of cellular energy metabolism, mainly via the regulation of mitochondria number and functions [11,12,13,14]. Interestingly, recent data imply that PGC-1α is also involved in the uptake, storage and turnover of glucose and FFAs [15,16].…”