Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 7, 2015; 21(25): 7764-7776
Published online Jul 7, 2015. doi: 10.3748/wjg.v21.i25.7764
Overexpression of HMGB1 A-box reduced lipopolysaccharide-induced intestinal inflammation via HMGB1/TLR4 signaling in vitro
Fu-Cai Wang, Jing-Xuan Pei, Jun Zhu, Nan-Jin Zhou, Dong-Sheng Liu, Hui-Fang Xiong, Xiao-Qun Liu, Dong-Jia Lin, Yong Xie
Fu-Cai Wang, Jing-Xuan Pei, Dong-Sheng Liu, Hui-Fang Xiong, Xiao-Qun Liu, Yong Xie, Department of Gastroenterology, the First Affiliated Hospital of Nanchang University, Gastroenterology Institute of Jiangxi Province, Key Laboratory of Digestive Diseases of Jiangxi Province, Nanchang 330006, Jiangxi Province, China
Fu-Cai Wang, Dong-Jia Lin, Department of Immunology, Medical College of Nanchang University, Nanchang 330006, Jiangxi Province, China
Jun Zhu, Department of Pathophysiology, Medical College of Nanchang University, 461 Bayi Road, Nanchang 330006, Jiangxi Province, China
Nan-Jin Zhou, Institute of Immunology and Biological Therapy, Jiangxi Academy of Medical Sciences, Nanchang 330006, Jiangxi Province, China
Author contributions: Wang FC, Pei JX and Zhu J contributed equally to this work; Zhou NJ and Xie Y designed and coordinated the research; Wang FC and Pei JX performed the majority of the experiments; Wang FC, Pei JX and Xie Y analyzed the data; Liu DS and Xiong HF contributed reagents/materials/analysis tools; Wang FC, Pei JX, Zhu J, Liu XQ, Lin DJ and Xie Y wrote the paper.
Supported by National Natural Science Foundation of China, No. 81160056; and the Youth Science Foundation of Jiangxi Provincial, China, No. 20132BAB215017.
Conflict-of-interest statement: The authors declare that there are no conflicts of interest related to the publication of this paper.
Data sharing statement: No additional unpublished data are available.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: Yong Xie, PhD, Professor, Chief Physician, Department of Gastroenterology, the First Affiliated Hospital of Nanchang University, Gastroenterology Institute of Jiangxi Province, Key Laboratory of Digestive Diseases of Jiangxi Province, No. 17 Yongwaizheng Street, Nanchang 330006, Jiangxi Province, China. xieyong_med@163.com
Telephone: +86-791-88692507 Fax: +86-791-88692507
Received: December 5, 2014
Peer-review started: December 6, 2014
First decision: December 22, 2014
Revised: January 12, 2015
Accepted: March 19, 2015
Article in press: March 19, 2015
Published online: July 7, 2015
Processing time: 215 Days and 11.9 Hours
Abstract

AIM: To investigate the inhibitory effects and mechanism of high mobility group box (HMGB)1 A-box in lipopolysaccharide (LPS)-induced intestinal inflammation.

METHODS: Overexpression of HMGB1 A-box in human intestinal epithelial cell lines (SW480 cells) was achieved using the plasmid pEGFP-N1. HMGB1 A-box-overexpressing SW480 cells were stimulated with LPS and co-culturing with human monocyte-like cell lines (THP-1 cells) using a Transwell system, compared with another HMGB1 inhibitor ethyl pyruvate (EP). The mRNA and protein levels of HMGB1/toll-like receptor (TLR) 4 signaling pathways [including HMGB1, TLR4, myeloid differentiation factor88 (MYD88), Phosphorylated Nuclear Factor κB (pNF-κB) p65] in the stimulated cells were determined by real-time polymerase chain reaction and Western blotting. The levels of the proinflammatory mediators [including HMGB1, interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α] in the supernatants of the stimulated cells were determined by ELISA.

RESULTS: EP downregulated the mRNA and protein levels of HMGB1, inhibited the TLR4 signaling pathways (TLR4, MYD88 and pNF-κB p65) and reduced the secretion of proinflammatory mediators (HMGB1, IL-1β, IL-6 and TNF-α) in the SW480 and THP-1 cells activated by LPS but not in the unstimulated cells. Activated by LPS, the overexpression of HMGB1 A-box in the SW480 cells also inhibited the HMGB1/TLR4 signaling pathways and reduced the secretion of these proinflammatory mediators in the THP-1 cells but not in the transfected and unstimulated cells.

CONCLUSION: HMGB1 A-box, not only EP, can reduce LPS-induced intestinal inflammation through inhibition of the HMGB1/TLR4 signaling pathways.

Keywords: High mobility group box 1; Toll-like receptor 4; HMGB1 A-box; Ethyl pyruvate; Inflammatory bowel disease

Core tip: We have provided the first report that high mobility group box (HMGB)1 A-box, not only ethyl pyruvate, can specifically inhibit HMGB1/toll-like receptor 4 signaling pathways and reduce lipopolysaccharide-induced intestinal inflammation. Our findings indicate the potential of the HMGB1 A-box as a novel approach in the treatment of inflammatory bowel disease.