Citreoviridin induces myocardial apoptosis through PPAR-γ-mTORC2-mediated autophagic pathway and the protective effect of thiamine and selenium

Citreoviridin (CIT), a mycotoxin and ATP synthase inhibitor, is regarded as one of aetiology factors of cardiac beriberi and Keshan disease. Thiamine (VB1) and selenium (Se) improve the recovery of these two diseases respectively. The underlying mechanisms of cardiotoxic effect of CIT and cardioprotective effect of VB1 and Se have not been fully elucidated. In this study, we found that ectopic ATP synthase was more sensitive to CIT treatment than mitochondrial ATP synthase in H9c2 cardiomyocytes. CIT inhibited the transcriptional activity of peroxisome proliferator activated receptor gamma (PPAR-gamma) in mice hearts and H9c2 cells. PPAR-gamma agonist attenuated the inhibitory effect of CIT on mechanistic target of rapamycin complex 2 (mTORC2) and stimulatory effect of CIT on autophagy in cardiomyocytes. CIT induced apoptosis through lysosomal-mitochondrial axis in cardiomyocytes. PPAR-gamma agonist and autophagy inhibitor alleviated CIT-induced apoptosis and accelerated cardiac biomarker. VB1 and Se accelerated the basal transcriptional activity of PPAR-gamma in mice hearts and H9c2 cells. Furthermore, VB1 and Se reversed the effect of CIT on PPAR-gamma, autophagy and apoptosis. Our findings defined PPAR-gamma-mTORC2-autophagy pathway as the key link between CIT cardiotoxicity and cardioprotective effect of VB1 and Se. The present study would shed new light on the pathogenesis of cardiomyopathy and the cardioprotective mechanism of micronutrients.