Ochratoxin A (OTA) could cause a variety of toxicological effects especially nephrotoxicity in animals and humans. Autophagy is a highly conserved metabolic process that plays an important role in the maintenance of cellular homeostasis under stress. However, the role of autophagy in OTA-induced nephrotoxicity is unknown. In the present study, we demonstrated that OTA treatment at 2.0–8.0 μM could increase cytotoxicity of PK-15 cells by inducing apoptosis as shown by the increased Annexin V/PI staining, increased caspase-3 and PARP cleavage and increased apoptotic nuclei. Meantime, autophagy was triggered when OTA was administrated, as indicated by markedly increased expressions of LC3-II, ATG5 and Beclin-1, accumulation of GFP-LC3 dots and increased double- or single-membrane vesicles. OTA treatment decreased p-AKT and p-mTOR activities, and OTA-induced autophagy was inhibited when insulin was applied. Furthermore, OTA treatments with autophagy inhibitors (3-methyladenine or chloroquine) or knockdown of autophagy-related genes (ATG5 or Beclin-1) resulted in significantly reduced autophagy level and enhanced cytotoxicity. In conclusion, OTA induces cytoprotective autophagy against its cytotoxicity and inactivation of AKT/mTOR axis plays a critical role in autophagy induction.

ch曲霉毒素A（OTA）可能引起多种毒理作用，尤其是对动物和人类的肾毒性。自噬是高度保守的代谢过程，在应激状态下维持细胞稳态方面起着重要作用。但是，自噬在OTA诱导的肾毒性中的作用尚不清楚。在本研究中，我们证明了2.0-8.0μM的OTA处理可以通过诱导凋亡来增加PK-15细胞的细胞毒性，这表现为膜联蛋白V / PI染色增加，caspase-3和PARP裂解增加以及凋亡核增加。同时，如通过显着增加LC3-II，ATG5和Beclin-1的表达，GFP-LC3点的积累以及增加双膜或单膜囊泡的显示，当施用OTA时会触发自噬。OTA处理可降低p-AKT和p-mTOR活性，当使用胰岛素时，OTA诱导的自噬被抑制。此外，用自噬抑制剂（3-甲基腺嘌呤或氯喹）进行OTA处理或敲除自噬相关基因（ATG5或Beclin-1）可导致自噬水平显着降低，并增强细胞毒性。总之，OTA诱导针对其细胞毒性的细胞保护性自噬，而AKT / mTOR轴的失活在自噬诱导中起关键作用。