Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 14, 2017; 23(2): 242-255
Published online Jan 14, 2017. doi: 10.3748/wjg.v23.i2.242
Recombinant adeno-associated virus carrying thymosin β4 suppresses experimental colitis in mice
Xiao-Yan Zheng, Yi-Fei Lv, Shuang Li, Qian Li, Qian-Nan Zhang, Xue-Ting Zhang, Zhi-Ming Hao
Xiao-Yan Zheng, Qian Li, Zhi-Ming Hao, Department of Rheumatology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
Yi-Fei Lv, Department of Gastroenterology, Shaanxi Provincial People’s Hospital, Xi’an 710061, Shaanxi Province, China
Shuang Li, Qian-Nan Zhang, Xue-Ting Zhang, Department of Gastroenterology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
Author contributions: Zheng XY and Hao ZM designed and coordinated the research; Li S and Zhang XT prepared the recombinant AAVs; Zheng XY, Lv YF and Zhang QN performed the animal experiments; Zheng XY, Lv YF, Li Q and Zhang QN performed the immunohistochemistry, TUNEL, ELISA and Western blot; Zheng XY and Li Q analyzed the data; Zheng XY and Hao ZM wrote the manuscript.
Supported by National Foundation of Natural Sciences, China, No. 81300293.
Institutional review board statement: The study was reviewed and approved by the Institutional Animal Ethics Committee of Xi’an Jiaotong University, Xi’an, Shaanxi Province, China (Permit No. XJTULAC2016-404).
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of Xi’an Jiaotong University, Xi’an, Shaanxi Province, China.
Conflict-of-interest statement: The authors declare that they have no conflict of interest to disclose concerning this manuscript.
Data sharing statement: 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: Zhi-Ming Hao, MD, PhD, Professor, Department of Rheumatology, The First Affiliated Hospital of Xi’an Jiaotong University, 277 Yantaxilu, Xi’an 710061, Shaanxi Province, China. haozhm66@126.com
Telephone: +86-18991232223
Received: June 25, 2016
Peer-review started: June 28, 2016
First decision: September 6, 2016
Revised: October 4, 2016
Accepted: November 13, 2016
Article in press: November 13, 2016
Published online: January 14, 2017
Abstract
AIM

To investigate the protective effect of a recombinant adeno-associated virus carrying thymosin β4 (AAV-Tβ4) on murine colitis via intracolonic administration.

METHODS

AAV-Tβ4 was prepared and intracolonically used to mediate the secretory expression of Tβ4 in mouse colons. Dextran sulfate sodium (DSS) was applied to induce the murine ulcerative colitis, and 2,4,6-trinitrobenzene sulfonic acid (TNBS) was used to establish a mouse colitis model resembling Crohn’s disease. The disease severity and colon injuries were observed and graded to reveal the effects of AAV-Tβ4 on colitis. The activities of myeloperoxidase (MPO) and superoxide dismutase (SOD) and the content of malondialdehyde (MDA) were determined using biochemical assays. Colonic levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-10 were measured using ELISA, and mucosal epithelial cell apoptosis and proliferation were detected by TUNEL assay and immunochemistry, respectively.

RESULTS

Recombinant AAVs efficiently delivered LacZ and Tβ4 into the colonic tissues of the mice, and AAV-Tβ4 led to a strong expression of Tβ4 in mouse colons. In both the DSS and TNBS colitis models, AAV-Tβ4-treated mice displayed distinctly attenuated colon injuries and reduced apoptosis rate of colonic mucosal epithelia. AAV-Tβ4 significantly reduced inflammatory cell infiltrations and relieved oxidative stress in the inflamed colons of the mice, as evidenced by decreases in MPO activity and MDA content and increases in SOD activity. AAV-Tβ4 also modulated colonic TNF-α, IL-1β and IL-10 levels and suppressed the compensatory proliferation of colonic epithelial cells in DSS- and TNBS-treated mice.

CONCLUSION

Tβ4 exerts a protective effect on murine colitis, indicating that AAV-Tβ4 could potentially be developed into a promising agent for the therapy of inflammatory bowel diseases.

Keywords: Thymosin β4, Mice, Colitis, Dextran sulfate sodium, 2,4,6-trinitrobenzene sulfonic acid

Core tip: We confirmed that intracolonically administered recombinant adeno-associated virus (AAVs) efficiently mediated the ectopic expression of LacZ and thymosin β4 (Tβ4) in mouse colonic mucosa. The current study first indicated that AAV-Tβ4 could improve murine colitis induced either by dextran sulfate sodium or 2,4,6-trinitrobenzene sulfonic acid by suppressing inflammatory cell infiltration, alleviating oxidative stress and epithelial apoptosis, and modulating the production of inflammatory mediators in the inflamed colon. Furthermore, locally overexpressed Tβ4 could attenuate the proliferation of colonic mucosal epithelia. In summary, these results suggest a protective role of Tβ4 in inflammatory bowel diseases (IBD) and indicate that AAV-Tβ4 has therapeutic potential for IBD patients.