Induction of apoptosis and autophagy via mitochondria- and PI3K/Akt/mTOR-mediated pathways by E. adenophorum in hepatocytes of saanen goat

Abstract

E. adenophorum has reported to cause hepatotoxicity. But, the precise effects of E. adenophorum on hepatocytes is unclear. Saanen goats were fed on E. adenophorum to detect the cytotoxicity effects of E. adenophorum on hepatocytes. Our study has shown that the typical apoptotic features, the increasing apoptotic hepatocytes and activated caspase-9, -3 and the subsequent cleavage of PARP indicated the potent pro-apoptotic effects of E. adenophorum. Moreover, the translocation of Bax and Cyt c between mitochondria and cytosol triggering the forming of apoptosome proved that the mitochondria-mediated apoptosis was triggered by E. adenophorum. Furthermore, E. adenophorum increased the MDC-positive autophagic vacuoles and the subcellular localization of punctate LC3, the ratio of LC3-II/LC3-I and the protein levels of Beclin 1, but decreased that of P62, indicating the potent pro-autophagic effects of E. adenophorum. In addition, E. adenophorum significantly inhibited the protein leves of p-PI3K, p-Akt and p-mTORC1, but increased PTEN and p-AMPK. Also, the p-mTORC2 and p-Akt Ser473 were inhibited, indicating that the supression of mTORC2/Akt pathway could induce the autophagy of hepatocytes. The autophagy-realted results indicated that the inhibition of PI3K/Akt/mTORC1- and mTORC2/Akt-mediated pathways contributed to the pro-autophagic activity of E. adenophorum. These findings provide new insights to understand the mechanisms involved in E. adenophorum-caused hepatotoxicity of Saanen goat.