title: Autophagy protects against palmitate-induced apoptosis in hepatocytes.
abstract: BACKGROUND
  Non-alcoholic fatty liver disease, one of the most common liver diseases, has obtained increasing attention. Palmitate (PA)-induced liver injury is considered a risk factor for the development of non-alcoholic fatty liver disease. Autophagy, a cellular degradative pathway, is an important self-defense mechanism in response to various stresses. In this study, we investigated whether autophagy plays a protective role in the progression of PA-induced hepatocytes injury.
  
  
  RESULTS
  Annexin V-FITC/PI staining by FCM analysis, TUNEL assay and the detection of PARP and cleaved caspase3 expression levels demonstrated that PA treatment prominently induced the apoptosis of hepatocytes. Meanwhile, treatment of PA strongly induced the formation of GFP-LC3 dots, the conversion from LC3I to LC3II, the decrease of p62 protein levels and the increase of autophagosomes. These results indicated that PA also induced autophagy activation. Autophagy inhibition through chloroquine pretreatment or Atg5shRNA infection led to the increase of cell apoptosis after PA treatment. Moreover, induction of autophagy by pretreatment with rapamycin resulted in distinct decrease of PA-induced apoptosis. Therefore, autophagy can prevent hepatocytes from PA-induced apoptosis. In the further study, we explored pathway of autophagy activation in PA-treated hepatocytes. We found that PA activated PKCα in hepatocytes, and had no influence on mammalian target of rapamycin and endoplasmic reticulum stress pathways.
  
  
  CONCLUSIONS
  These results demonstrated that autophagy plays a protective role in PA-induced hepatocytes apoptosis. And PA might induce autophagy through activating PKCα pathway in hepatocytes.
authors.affiliation: Medical Sciences Research Center, Ren Ji hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Cai
authors.affiliation: Medical Sciences Research Center, Ren Ji hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Tumor Immunology and Gene Therapy Center, Eastern Hepatobiliary Surgery Hospital, The Second Military Medical University, Shanghai, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Jing
authors.affiliation: Medical Sciences Research Center, Ren Ji hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Sun
authors.affiliation: Medical Sciences Research Center, Ren Ji hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Shufan
authors.initials: S
authors.lastname: Jiao
authors.affiliation: Medical Sciences Research Center, Ren Ji hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Chen
authors.affiliation: Medical Sciences Research Center, Ren Ji hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Haozheng
authors.initials: H
authors.lastname: Yang
authors.affiliation: Medical Sciences Research Center, Ren Ji hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Medical Sciences Research Center, Ren Ji hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China ; Tumor Immunology and Gene Therapy Center, Eastern Hepatobiliary Surgery Hospital, The Second Military Medical University, Shanghai, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Wei
keywords: Apoptosis; Autophagy; Hepatocytes; Palmitate; Protector