SIRT1 protects cardiac cells against apoptosis induced by zearalenone or its metabolites α- and β-zearalenol through an autophagy-dependent pathway

(\)Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium in cereals and agricultural products. The major ZEN metabolites are alpha-zearalenol (alpha-ZOL) and beta-zearalenol (beta-zoL). In the present study, we investigated the underlying mechanism of the toxicity induced by ZEN, alpha-ZOL and beta-ZOL in cardiac cells (H9c2). We show that treatment with ZEN or its metabolites induces the activation of the mitochondria! pathway of apoptosis as characterized by an increase in ROS generation, a loss of mitochondria( trans membrane potential (Delta Psi m) and an activation of caspases. Besides, we demonstrate that these mycotoxins promote the activation of autophagy before the onset of apoptosis. Indeed, we observed that a short-time (6 h) treatment with ZEN, alpha-ZOL or beta-ZOL, increased the level of Beclin-1 and LC3-II and induced the accumulation of the CytolD (R) autophagy detection probe. Moreover, the inhibition of autophagy by Chloroquine significantly increased cell death induced by ZEN, alpha-ZOL or beta-ZOL, suggesting that the activation of autophagy serves as a cardioprotective mechanism against these mycotoxins. In addition, we found that the inhibition (EX527) or the knockdown of SIRT1 (siRNA) significantly increased apoptosis induced by ZEN or its derivatives, whereas SIRT1 activation with RSV greatly prevents the cytotoxic effects of these mycotoxins. By contrast, when autophagy was inhibited by CQ the activation of SIRT1 by RSV had no protection against the cardiotoxicity of ZEN or its metabolites, suggesting that SIRT1 protects cardiac cells by an autophagy-dependent pathway. (C) 2016 Elsevier Inc. All rights reserved.