title: Restoration of autophagy by puerarin in ethanol-treated hepatocytes via the activation of AMP-activated protein kinase.
abstract: We investigated the effects of puerarin, the major isoflavone in Kudzu roots, on the regulation of autophagy in ethanol-treated hepatocytes. Incubation in ethanol (100 mM) for 24 h reduced cell viability by 20% and increased the cellular concentrations of cholesterol and triglycerides by 40% and 20%, respectively. Puerarin stimulation significantly recovered cell viability and reduced cellular lipid accumulation to a level comparable to that in untreated control cells. Ethanol incubation reduced autophagy significantly as assessed by microtubule-associated protein1 light chain 3 (LC3) expression using immunohistochemistry and immunoblot analysis. The reduced expression of LC3 was restored by puerarin in a dose-dependent manner in ethanol-treated cells. The effect of puerarin on mammalian targets of rapamycin (mTOR), a key regulator of autophagy, was examined in ethanol-treated hepatocytes. Immunoblotting revealed that puerarin significantly induced the phosphorylation of 5'AMP-activated protein kinase (AMPK), thereby suppressing the mTOR target proteins S6 ribosomal protein and 4E-binding protein 1. These data suggest that puerarin restored the viability of cells and reduced lipid accumulation in ethanol-treated hepatocytes by activating autophagy via AMPK/mTOR-mediated signaling.
authors.affiliation: Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea. ropang@korea.ac.kr
authors.forename: Byung-Kyu
authors.initials: BK
authors.lastname: Noh
authors.forename: Jung Kyu
authors.initials: JK
authors.lastname: Lee
authors.forename: Hee-jin
authors.initials: HJ
authors.lastname: Jun
authors.forename: Ji Hae
authors.initials: JH
authors.lastname: Lee
authors.forename: Yaoyao
authors.initials: Y
authors.lastname: Jia
authors.forename: Minh-Hien
authors.initials: MH
authors.lastname: Hoang
authors.forename: Jung-Wan
authors.initials: JW
authors.lastname: Kim
authors.forename: Kwan-Hwa
authors.initials: KH
authors.lastname: Park
authors.forename: Sung-Joon
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000096:biosynthesis*; D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D045744:Cell Line, Tumor; D004789:Enzyme Activation; D000431:Ethanol / Q000494:pharmacology*; D022781:Hepatocytes / Q000187:drug effects* / Q000201:enzymology; D007529:Isoflavones / Q000494:pharmacology*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D051381:Rats
chemical_list: D055372:AMP-Activated Protein Kinases; D000431:Ethanol; D007529:Isoflavones; D008869:Microtubule-Associated Proteins; C526109:Anxa3 protein, rat; C033607:puerarin