TY - JOUR
T1 - The transcription factor interferon regulatory factor-1 mediates liver damage during ischemia-reperfusion injury
AU - Tsung, Allan
AU - Stang, Michael T.
AU - Ikeda, Atsushi
AU - Critchlow, Nathan D.
AU - Izuishi, Kunihiko
AU - Nakao, Atsunori
AU - Chan, Meagan H.
AU - Jeyabalan, Geetha
AU - Yim, John H.
AU - Geller, David A.
PY - 2006/6
Y1 - 2006/6
N2 - Hepatic ischemia occurs in the settings of trauma, transplantation, and elective liver resections. The initiating events that account for local organ damage are only partially understood. Interferon (IFN) regulatory factor-1 (IRF-1) is a transcription factor that regulates the expression of a number of genes involved in both innate and acquired immunity; however, its function in liver injury is unknown. Therefore, the purpose of this study was to investigate the role of IRF-1 in hepatic ischemia-reperfusion (I/R) injury. In C57BL/6 mice undergoing 60 min of hepatic ischemia, IRF-1 protein expression increased as early as 1 h after reperfusion. IRF-1 knockout mice were significantly protected from hepatic I/R-induced damage compared with their wild-type controls. Hepatic I/R injury resulted in marked activation of the MAP kinase c-Jun NH 2-terminal kinase (JNK) in wild-type mice but not IRF-1 knockout mice. IRF-1 knockout mice also exhibited significantly lower hepatic expression of TNF-α, IL-6, ICAM-1, and inducible nitric oxide synthase (iNOS) mRNA. Adenoviral delivery of IRF-1 into C57BL/6 mice resulted in increased liver damage even without an ischemic insult. This injury was associated with increased JNK activation and hepatic iNOS expression. Because IRF-1 contributed to liver injury, we also examined for inflammatory signals that regulated IRF-1 gene expression in cultured hepatocytes. Whereas IFN-γ and IFN-β were strong inducers of IRF-1 mRNA (>10-fold) in a time- and dose-dependent manner, TNF-α and IL-1β also induced IRF-1 mRNA to a lesser extent (2- to 3-fold). IL-6 and lipopolysaccharide had no effect on IRF-1 expression. This study demonstrates that IRF-1 exerts a harmful role in hepatic I/R injury by modulating the expression of multiple inflammatory mediators. We further show that IRF-1-mediated injury involves the activation of JNK and that hepatocellular IRF-1 expression itself is regulated by specific cytokines.
AB - Hepatic ischemia occurs in the settings of trauma, transplantation, and elective liver resections. The initiating events that account for local organ damage are only partially understood. Interferon (IFN) regulatory factor-1 (IRF-1) is a transcription factor that regulates the expression of a number of genes involved in both innate and acquired immunity; however, its function in liver injury is unknown. Therefore, the purpose of this study was to investigate the role of IRF-1 in hepatic ischemia-reperfusion (I/R) injury. In C57BL/6 mice undergoing 60 min of hepatic ischemia, IRF-1 protein expression increased as early as 1 h after reperfusion. IRF-1 knockout mice were significantly protected from hepatic I/R-induced damage compared with their wild-type controls. Hepatic I/R injury resulted in marked activation of the MAP kinase c-Jun NH 2-terminal kinase (JNK) in wild-type mice but not IRF-1 knockout mice. IRF-1 knockout mice also exhibited significantly lower hepatic expression of TNF-α, IL-6, ICAM-1, and inducible nitric oxide synthase (iNOS) mRNA. Adenoviral delivery of IRF-1 into C57BL/6 mice resulted in increased liver damage even without an ischemic insult. This injury was associated with increased JNK activation and hepatic iNOS expression. Because IRF-1 contributed to liver injury, we also examined for inflammatory signals that regulated IRF-1 gene expression in cultured hepatocytes. Whereas IFN-γ and IFN-β were strong inducers of IRF-1 mRNA (>10-fold) in a time- and dose-dependent manner, TNF-α and IL-1β also induced IRF-1 mRNA to a lesser extent (2- to 3-fold). IL-6 and lipopolysaccharide had no effect on IRF-1 expression. This study demonstrates that IRF-1 exerts a harmful role in hepatic I/R injury by modulating the expression of multiple inflammatory mediators. We further show that IRF-1-mediated injury involves the activation of JNK and that hepatocellular IRF-1 expression itself is regulated by specific cytokines.
KW - Cytokines
KW - Hepatic ischemia
KW - Inducible nitric oxide synthase
KW - Liver injury
KW - c-Jun NH-terminal kinase
UR - http://www.scopus.com/inward/record.url?scp=33646886598&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33646886598&partnerID=8YFLogxK
U2 - 10.1152/ajpgi.00460.2005
DO - 10.1152/ajpgi.00460.2005
M3 - Article
C2 - 16410367
AN - SCOPUS:33646886598
SN - 0193-1857
VL - 290
SP - G1261-G1268
JO - American Journal of Physiology - Gastrointestinal and Liver Physiology
JF - American Journal of Physiology - Gastrointestinal and Liver Physiology
IS - 6
ER -