Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Nov 14, 2016; 22(42): 9368-9377
Published online Nov 14, 2016. doi: 10.3748/wjg.v22.i42.9368
IRF5 regulates lung macrophages M2 polarization during severe acute pancreatitis in vitro
Kang Sun, Song-Bing He, Jian-Guo Qu, Sheng-Chun Dang, Ji-Xiang Chen, Ai-Hua Gong, Rong Xie, Jian-Xin Zhang
Kang Sun, Jian-Guo Qu, Sheng-Chun Dang, Ji-Xiang Chen, Rong Xie, Jian-Xin Zhang, Department of General Surgery, The Affiliated Hospital of Jiangsu University, Zhenjiang 212001, Jiangsu Province, China
Song-Bing He, Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
Ai-Hua Gong, Medical School of Jiangsu University, Zhenjiang 212013, Jiangsu Province, China
Author contributions: Sun K and He SB contributed equally to this work; Sun K and He SB analyzed the data; Sun K and He SB wrote the paper; Sun K, He SB, Qu JG, Dang SC, Chen JX and Xie R performed the research; Sun K, He SB and Zhang JX designed the research; Sun K and Gong AH contributed new reagents or analytic tools.
Supported by Graduate Innovative Projects in Jiangsu Province, No. 1201270052; Zhenjiang Science and Technology Program, No. SH2013032; National Natural Science Foundation of China, No. 81672348; Six-Major-Peak- Talent Project of Jiangsu Province of China, No. 2015-WSW-014; and the Scientific Research Fund for the Returned Overseas Chinese Scholars, State Ministry of Education, No. the 50th batch, 2015.
Institutional review board statement: The study was reviewed and approved by Jiangsu University Institutional Review Board.
Institutional animal care and use committee statement: All animal protocols received prior approval from the Institutional Animal Care and Use Committee and all experiments were performed in accordance with guidelines and regulations of Laboratory Animal Center of Jiangsu University, Zhenjiang, China.
Conflict-of-interest statement: The authors declared that no conflict of interest exists in this study.
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: Jian-Xin Zhang, MD, Professor, Department of General Surgery, The Affiliated Hospital of Jiangsu University, No. 438 Jiefang Road, Zhenjiang 212001, Jiangsu Province, China. doctorsunkang@126.com
Telephone: + 86-511-85082208 Fax: + 86-511-85082208
Received: June 26, 2016
Peer-review started: June 27, 2016
First decision: July 29, 2016
Revised: August 13, 2016
Accepted: August 23, 2016
Article in press: August 23, 2016
Published online: November 14, 2016
Abstract
AIM

To investigate the role of interferon regulatory factor 5 (IRF5) in reversing polarization of lung macrophages during severe acute pancreatitis (SAP) in vitro.

METHODS

A mouse SAP model was established by intraperitoneal (ip) injections of 20 μg/kg body weight caerulein. Pathological changes in the lung were observed by hematoxylin and eosin staining. Lung macrophages were isolated from bronchoalveolar lavage fluid. The quantity and purity of lung macrophages were detected by fluorescence-activated cell sorting and evaluated by real-time polymerase chain reaction (RT-PCR). They were treated with IL-4/IRF5 specific siRNA (IRF5 siRNA) to reverse their polarization and were evaluated by detecting markers expression of M1/M2 using RT-PCR.

RESULTS

SAP associated acute lung injury (ALI) was induced successfully by ip injections of caerulein, which was confirmed by histopathology. Lung macrophages expressed high levels of IRF5 as M1 phenotype during the early acute pancreatitis stages. Reduction of IRF5 expression by IRF5 siRNA reversed the action of macrophages from M1 to M2 phenotype in vitro. The expressions of M1 markers, including IRF5 (S + IRF5 siRNA vs S + PBS, 0.013 ± 0.01 vs 0.054 ± 0.047, P < 0.01), TNF-α (S + IRF5 siRNA vs S + PBS, 0.0003 ± 0.0002 vs 0.019 ± 0.018, P < 0.001), iNOS (S + IRF5 siRNA vs S + PBS, 0.0003 ± 0.0002 vs 0.026 ± 0.018, P < 0.001) and IL-12 (S + IRF5 siRNA vs S + PBS, 0.000005 ± 0.00004 vs 0.024 ± 0.016, P < 0.001), were decreased. In contrast, the expressions of M2 markers, including IL-10 (S + IRF5 siRNA vs S + PBS, 0.060 ± 0.055 vs 0.0230 ± 0.018, P < 0.01) and Arg-1 (S + IRF5 siRNA vs S + PBS, 0.910 ± 0.788 vs 0.0036 ± 0.0025, P < 0.001), were increased. IRF5 siRNA could reverse the lung macrophage polarization more effectively than IL-4.

CONCLUSION

Treatment with IRF5 siRNA can reverse the pancreatitis-induced activation of lung macrophages from M1 phenotype to M2 phenotype in SAP associated with ALI.

Keywords: Interferon regulatory factor 5, Macrophage polarization, Severe acute pancreatitis, SiRNA

Core tip: We investigated the role of interferon regulatory factor 5 (IRF5) in reversing polarization of lung macrophages during severe acute pancreatitis (SAP). Treatment with IRF5 specific siRNA could reverse the pancreatitis-induced activation of lung macrophages from M1 phenotype to M2 phenotype in vitro. Reduced expression of IRF5 may lead to a new therapeutic approach for SAP associated with acute lung injury.