한빛사논문
Abstract
Adam C. Labonte1,2, Sun-Sang J. Sung1,3, Lucas T. Jennelle1,2, Aditya P. Dandekar1 and Young S. Hahn1,2,*
1 Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, VA
2 Department of Microbiology, University of Virginia, Charlottesville, VA
3 Department of Medicine & Center for Inflammation and Regeneration, University of Virginia, Charlottesville, VA
*Corresponding author: Young S. Hahn, PhD, Carter Immunology Center, University of Virginia School of Medicine, P.O. Box 801386, Charlottesville, VA, USA 22908,
Abstract
The liver maintains an immunologically tolerant environment as a result of continuous exposure to food and bacterial constituents from the digestive tract. Hepatotropic pathogens can take advantage of this niche and establish lifelong chronic infections causing hepatic fibrosis and hepatocellular carcinoma. Macrophages (Mϕ) play a critical role in regulation of immune responses to hepatic infection and regeneration of tissue. However, the factors crucial for Mϕ in limiting hepatic inflammation or resolving liver damage have not been fully understood. In this report, we demonstrate that the expression of C-type lectin receptor scavenger receptor-AI (SR-AI) is crucial for promoting M2-like Mϕ activation and polarization during hepatic inflammation. Liver Mϕ uniquely upregulated SR-AI during hepatotropic viral infection and displayed increased expression of alternative Mϕ activation markers such as YM-1, arginase-1, and IL-10 via the activation of Mertk associated with inhibition of mTOR. The expression of these molecules was reduced on Mϕ obtained from the livers of infected mice deficient for the gene encoding SR-AI (msr1). Furthermore, in vitro studies using an SR-AI-deficient Mϕ cell line revealed impeded M2 polarization and decreased phagocytic capacity. Direct stimulation with virus was sufficient to activate M2 gene expression in the wild type (WT) cell line but not in the knockdown cell line. Importantly, tissue damage and fibrosis were exacerbated in SR-AI-/- mice following hepatic infection and adoptive transfer of WT bone marrow derived Mϕ conferred protection against fibrosis in these mice.
Conclusion: SR-AI expression on liver Mϕ promotes recovery from infection-induced tissue damage by mediating
a switch to a pro-resolving Mϕ polarization state. This article is protected by copyright. All rights reserved.
Keywords : SR-AI; M1; M2; polarization; fibrosis
논문정보
관련 링크