Logo image
JunD Protects the Liver from Ischemia/Reperfusion Injury by Dampening AP-1 Transcriptional Activation
Journal article   Open access   Peer reviewed

JunD Protects the Liver from Ischemia/Reperfusion Injury by Dampening AP-1 Transcriptional Activation

Jennifer J Marden, Yulong Zhang, Fredrick D Oakley, Weihong Zhou, Meihui Luo, Hong Peng Jia, Paul B McCray, Moshe Yaniv, Jonathan B Weitzman and John F Engelhardt
The Journal of biological chemistry, Vol.283(11), pp.6687-6695
03/14/2008
DOI: 10.1074/jbc.M705606200
PMCID: PMC3593645
PMID: 18182393
url
https://doi.org/10.1074/jbc.M705606200View
Published (Version of record) Open Access

Abstract

The AP-1 transcription factor modulates a wide range of cellular processes, including cellular proliferation, programmed cell death, and survival. JunD is a major component of the AP-1 complex following liver ischemia/reperfusion (I/R) injury; however, its precise function in this setting remains unclear. We investigated the functional significance of JunD in regulating AP-1 transcription following partial lobar I/R injury to the liver, as well as the downstream consequences for hepatocellular remodeling. Our findings demonstrate that JunD plays a protective role, reducing I/R injury to the liver by suppressing acute transcriptional activation of AP-1. In the absence of JunD, c-Jun phosphorylation and AP-1 activation in response to I/R injury were elevated, and this correlated with increased caspase activation, injury, and alterations in hepatocyte proliferation. The expression of dominant negative JNK1 inhibited c-Jun phosphorylation, AP-1 activation, and hepatic injury following I/R in JunD −/− mice but, paradoxically, led to an enhancement of AP-1 activation and liver injury in JunD +/− littermates. Enhanced JunD/JNK1-dependent liver injury correlated with the acute induction of diphenylene iodonium-sensitive NADPH-dependent superoxide production by the liver following I/R. In this context, dominant negative JNK1 expression elevated both Nox2 and Nox4 mRNA levels in the liver in a JunD-dependent manner. These findings suggest that JunD counterbalances JNK1 activation and the downstream redox-dependent hepatic injury that results from I/R, and may do so by regulating NADPH oxidases.

Details

Metrics

Logo image