Transcription factor EB (TFEB)-mediated autophagy protects bovine mammary epithelial cells against H2O2-induced oxidative damage in vitro
Xudong Sun, Renxu Chang, Yan Tang, Shengbin Luo, Chunhui Jiang, Hongdou Jia, Qiushi Xu, Zhihao Dong, Yusheng Liang, Juan J. Loor, Chuang Xu
Abstract
Abstract Background Bovine mammary epithelial cells after calving undergo serious metabolic challenges and oxidative stress both of which could compromise autophagy. Transcription factor EB (TFEB)-mediated autophagy is an important cytoprotective mechanism against oxidative stress. However, effects of TFEB-mediated autophagy on the oxidative stress of bovine mammary epithelial cells remain unknown. Therefore, the main aim of the study was to investigate the role of TFEB-mediated autophagy in bovine mammary epithelial cells experiencing oxidative stress. Results H 2 O 2 challenge of the bovine mammary epithelial cell MAC-T increased protein abundance of LC3-II, increased number of autophagosomes and autolysosomes while decreased protein abundance of p62. Inhibition of autophagy via bafilomycin A1 aggravated H 2 O 2 -induced reactive oxygen species (ROS) accumulation and apoptosis in MAC-T cells. Furthermore, H 2 O 2 treatment triggered the translocation of TFEB into the nucleus. Knockdown of TFEB by siRNA reversed the effect of H 2 O 2 on protein abundance of LC3-II and p62 as well as the number of autophagosomes and autolysosomes. Overexpression of TFEB activated autophagy and attenuated H 2 O 2 -induced ROS accumulation. Furthermore, TFEB overexpression attenuated H 2 O 2 -induced apoptosis by downregulating the caspase apoptotic pathway. Conclusions Our results indicate that activation of TFEB mediated autophagy alleviates H 2 O 2 -induced oxidative damage by reducing ROS accumulation and inhibiting caspase-dependent apoptosis.