HNE interacts directly with JNK isoforms in human hepatic stellate cells

4-Hydroxy-2,3-nonenal (HNE) is an aldehydic end product of lipid peroxidati on which has been detected in vivo in clinical and experimental conditions of chronic Liver damage. PINE has been shown to stimulate procollagen type I gene expression and synthesis in human hepatic stellate cells (hHSC) whic h are known to play a key role in liver fibrosis. In this study we investig ated the molecular mechanisms underlying HNE actions in cultured hHSC, PINE , at doses compatible with those detected in vivo, lead to an early generat ion of nuclear HNE-protein adducts of 46, 54, and 66 kD, respectively, as r evealed by using a monoclonal antibody specific for HNE-histidine adducts. This observation is related to the lack of crucial HNE-metabolizing enzymat ic activities in hHSC, Kinetics of appearance of these nuclear adducts sugg ested translocation of cytosolic proteins. The p46 and p54 isoforms of c-Ju n amino-terminal kinase (JNKs) were identified as PINE targets and were act ivated by this aldehyde, A biphasic increase in AP-1 DNA binding activity, associated with increased mRNA levels of c-jun, was also observed in respon se to HNE. HNE did not affect the Ras/ERK pathway, c-fos expression, DNA sy nthesis, or NF-KB binding. This study identifies a novel mechanism linking oxidative stress to nuclear signaling in hHSC. This mechanism is not based on redox sensors and is stimulated by concentrations of HNE compatible with those detected in vivo, and thus may be relevant during chronic liver dise ases.