Inhibition of mevalonate pathway prevents ischemia-induced cardiac dysfunction in rats via RhoA-independent signaling pathway.

Abstract

We previously demonstrated that anoxia-mediated Ca2+ handling dysfunction could be ameliorated through inhibition of mevalonate pathway via RhoA- and Ras-related mechanisms in H9c2 cells. In this study, we further explored whether inhibition of mevalonate pathway is associated with cardiac remodeling and dysfunction in ischemic cardiomyopathy, and discussed the possible role of Ras, Rac and RhoA in cardiac dysfunction. We investigated the role of mevalonate pathway in cardiac remodeling and cardiomyocyte Ca2+ handling proteins expression in a rat model of cardiac dysfunction due to myocardial infarction (MI). After MI, adult male Sprague-Dawley rats were treated with drugs that antagonize key components in mevalonate pathway, including 3-hydroxy-3-methylglutaryl-CoA reductase, farnesyl pyrophosphate synthase, and Rho-kinase for 10weeks. The protein expression of ryanodine receptor 2 (RyR2), sarcoplasmic reticulum Ca2+ ATPase (SERCA) 2a, phospholamban (PLB), phospho-PLB at serine-16 (PSer16-PLB), FKBP12.6, and RhoA as well as RyR2 and FKBP12.6 mRNA levels was evaluated. Rosuvastatin and alendronate treatment prevented myocardial remodeling, improved cardiac function and reduced infarct size. Furthermore, rosuvastatin and alendronate promoted an increase in the protein expression of SERCA2a and PSer16-PLB/PLB ratio as well as partially restored the RyR2 and FKBP12.6 gene and protein expression. Fasudil failed to exert these beneficial effects. These findings indicate that mevalonate pathway inhibition by rosuvastatin and alendronate prevents cardiac remodeling and dysfunction possibly through RhoA-independent mechanisms.