Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 7, 2015; 21(17): 5250-5258
Published online May 7, 2015. doi: 10.3748/wjg.v21.i17.5250
Autophagy in anti-apoptotic effect of augmenter of liver regeneration in HepG2 cells
Hong-Bo Shi, Hai-Qing Sun, Hong-Lin Shi, Feng Ren, Yu Chen, De-Xi Chen, Jin-Li Lou, Zhong-Ping Duan
Hong-Bo Shi, Hai-Qing Sun, Hong-Lin Shi, Feng Ren, Yu Chen, De-Xi Chen, Jin-Li Lou, Zhong-Ping Duan, Beijing Youan Hospital, Capital Medical University, Beijing 100069, China
Hong-Bo Shi, Hai-Qing Sun, Hong-Lin Shi, Feng Ren, De-Xi Chen, Zhong-Ping Duan, Beijing Institute of Hepatology, Beijing 100069, China
Author contributions: Shi HB and Sun HQ contributed equally to this study; Shi HB performed the plasmid infection and fluorescence microscopy assays, analyzed the data and wrote the manuscript; Sun HQ performed cell culture, immunofluorescence, Western blotting and quantitative polymerase chain reaction assays; Shi HL performed flow cytometry assays; Ren F and Chen Y performed electron microscopy assays; Chen DX provided the LC3 plasmid; Lou JL and Duan ZP conceived and designed the study; and Duan ZP was involved in editing the manuscript.
Supported by National Natural Science Foundation of China, No. 81300349 and No. 81270532; Beijing Natural Science Foundation, No. 7144216; Beijing Nova Program, No. Z131107000413016; Project of Science and Technology Activities of Preferred Overseas Personnel of Beijing (2014); and Project of Cultivation of High Level Medical Technical Personnel in Health System of Beijing.
Ethics approval: This study was reviewed and approved by the Ethics Committee of Beijing Youan Hospital, Capital Medical University.
Institutional animal care and use committee: Not applicable: no animals were used in this study.
Conflict-of-interest: Hong-Bo Shi, Hai-Qing Sun, Hong-Lin Shi, Feng Ren, Yu Chen, De-Xi Chen, Jin-Li Lou and Zhong-Ping Duan are employees of Beijing Youan Hospital, Capital Medical University. The authors declare no conflicts of interest.
Data sharing: Technical appendices, statistical codes, and datasets are available from the corresponding author at duan2517@163.com. Participants provided informed consent for data sharing. No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Zhong-Ping Duan, MD, PhD, Professor of medicine, Beijing Youan Hospital, Capital Medical University, Beijing 100069, China. duan2517@163.com
Telephone: +86-10-63291007 Fax: +86-10-63295258
Received: October 31, 2014
Peer-review started: November 3, 2014
First decision: November 26, 2014
Revised: December 22, 2014
Accepted: February 11, 2015
Article in press: February 11, 2015
Published online: May 7, 2015
Processing time: 193 Days and 17.7 Hours
Abstract

AIM: To investigate the role of autophagy in the anti-apoptotic effect of augmenter of liver regeneration (ALR).

METHODS: Autophagy was induced through serum deprivation. An ALR-expressing plasmid was transfected into HepG2 cells, and autophagic flux was determined using fluorescence microscopy, electron microscopy, Western blot and quantitative polymerase chain reaction (qPCR) assays. After ALR-expressing plasmid transfection, an autophagy inhibitor [3-methyladenine (3-MA)] was added to HepG2 cells, and apoptosis was observed using fluorescence microscopy and flow cytometry.

RESULTS: Autophagy was activated in HepG2 cells, peaking at 24 h after serum deprivation. Microtubule-associated protein light chain three-II levels were higher in HepG2 cells treated with ALR than in control cells, fluorescence microscopy, electron microscopy and qPCR studies showed the similar trend, and p62 levels showed the opposite trend, which indicated that ALR may play an important role in increasing autophagy flux. The numbers of apoptotic cells were substantially higher in HepG2 cells treated with both ALR and 3-MA than in cells treated with ALR alone. Therefore, the protective effect of ALR was significantly attenuated or abolished when autophagy was inhibited, indicating that the anti-apoptotic effect of ALR may be related to autophagy.

CONCLUSION: ALR protects cells from apoptosis partly through increased autophagy in HepG2 cells and may be valuable as a new therapeutic treatment for liver disease.

Keywords: Autophagy; Augmenter of liver regeneration; Apoptosis; HepG2 cells

Core tip: Recent studies have found that augmenter of liver regeneration (ALR) plays an important role in suppressing hepatocyte apoptosis, although the mechanism remains unknown. Our study shows that ALR plays an important role in increasing the level of autophagy in HepG2 cells. The protective effect of ALR was significantly attenuated or abolished when autophagy was inhibited, indicating that the anti-apoptotic effect of ALR may be related to autophagy. Hence, we conclude that ALR protects cells against apoptosis partly by increasing autophagic activity in HepG2 cells and may be valuable for developing new therapeutic treatments for liver disease.