Transcription factor EB (TFEB)-mediated autophagy protects bovine mammary epithelial cells against H₂O₂-induced oxidative damage in vitro

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: H₂O₂ 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 H₂O₂-induced reactive oxygen species (ROS) accumulation and apoptosis in MAC-T cells. Furthermore, H₂O₂ treatment triggered the translocation of TFEB into the nucleus. Knockdown of TFEB by siRNA reversed the effect of H₂O₂ on protein abundance of LC3-II and p62 as well as the number of autophagosomes and autolysosomes. Overexpression of TFEB activated autophagy and attenuated H₂O₂-induced ROS accumulation. Furthermore, TFEB overexpression attenuated H₂O₂-induced apoptosis by downregulating the caspase apoptotic pathway. Conclusions: Our results indicate that activation of TFEB mediated autophagy alleviates H₂O₂-induced oxidative damage by reducing ROS accumulation and inhibiting caspase-dependent apoptosis.