Favored T helper 1 response in a mouse model of... : Hepatology (original) (raw)
Liver Biology and Pathobiology: Pathobiology
Favored T helper 1 response in a mouse model of hepatosteatosis is associated with enhanced T cell–mediated hepatitis
Kremer, Michael1,*; Hines, Ian Neil1; Milton, Richard Jameson1; Wheeler, Michael Daryl1,2
1_Center for Alcohol Studies, The University of North Carolina at Chapel Hill, NC_
2_Department of Nutrition, The University of North Carolina at Chapel Hill, NC_
*Skipper Bowles Center for Alcohol Studies, CB# 7178, 3011 Thurston-Bowles Building, University of North Carolina, Chapel Hill, NC 27599
Email:[email protected]
Received 5 August 2005; Accepted 17 March 2006
Published online in Wiley InterScience (www.interscience.wiley.com).
Grant sponsor: NIH; Grant Number: AA014243.
Potential conflict of interest: Nothing to report.
fax: 919-966-1893
Abstract
Steatohepatitis enhances the severity of liver injury caused by acute inflammation. The purpose of this study was to test the hypothesis that fatty liver due to chronic choline-deficient diet exacerbates concanavalin A (ConA)-induced liver hepatitis, which is predominantly facilitated by T cells. Male C57BL/6 mice were fed either control choline-sufficient diet (CSD) or choline-deficient diet (CDD) for 6 weeks before ConA administration. Mice were sacrificed 3, 9, and 24 hours after ConA injection. Liver injury measured by aspartate aminotransferase (AST), alanine aminotransferase (ALT), pathology, and terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) staining was minimal in mice fed either diet before ConA exposure. However, ConA-induced liver injury was significantly greater in CDD-fed mice compared with control-fed mice. Liver cytokines were assessed by quantitative real-time polymerase chain reaction (PCR). The expression of T helper (Th) 1 cytokines tumor necrosis factor alpha (TNF-α), interleukin 12 (IL-12), and interferon gamma (IFN-γ) were dramatically elevated after ConA in CDD-fed mice compared with control-fed mice. CDD also enhanced ConA-induced STAT4 activation, but not STAT6. Notably, regulators of T-cell differentiation were strongly shifted toward a predominant Th1 profile. T-bet, regulator of the Th1 response, was up-regulated in CDD-fed mice, whereas Th2 regulator GATA-3 was significantly suppressed in CDD-fed mice after ConA. Moreover, the expression of suppressor of cytokine signaling (SOCS)-1, SOCS-3, and repressor of GATA-3 (ROG) favored a predominant Th1 cytokine response in CDD-fed mice. In conclusion , these data support the hypothesis that hepatosteatosis caused by CDD is associated with more severe ConA-induced hepatitis due to a predominant shift toward Th1 response.
Copyright © 2006 American Association for the Study of Liver Diseases.