Involvement of the electrophile responsive element and p53 in the activation of hepatic stellate cells as a response to electrophile menadione.
The cytotoxic effects of menadione and hydrogen peroxide were examined in two hepatic stellate cell lines derived from normal or cirrhotic rat liver. The cirrhotic fat-storing cells (CFSC) were found more resistant than the normal fat-storing cells (NFSC) to menadione cytotoxicity. No significant differences were observed in hydrogen peroxide toxicity in these two cell lines. Although protein levels and enzymatic activities of catalase, Cu,Zn-SOD, Mn-SOD, and NADPH cytochrome c reductase were similar in these cell lines, 20-fold increases of NAD(P)H:quinone oxidoreductase 1 (NQO1) enzymatic activity and protein levels were detected in CFSC compared to those of NFSC. Gel mobility shift assays and functional analysis using transient transfection experiments indicated the involvement of the electrophile responsive element (EPRE) in the up-regulation of the NQO1 expression. Antibody supershift analysis revealed that, although Nrf2 is a member of the EPRE-binding complex in both NFSC and CFSC, Nrf1 was identified as a part of the protein/DNA complex only in CFSC. Expression of p53 tumor suppressor gene was found in higher levels in CFSC than in NFSC. We conclude that activation of the EPRE-signaling pathway, which up-regulates several phase II genes and affects p53 stabilization, may offer resistance to hepatic stellate cells against oxidative damage during hepatic injury. This resistance may be a part of the activation process of the hepatic stellate cells and could contribute to their increased proliferation and production of extracellular matrix.
Molecular Toxicology and Environmental Health Sciences Program, Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, P.O. Box C238, Denver, CO 80262, USA. vasilis.vasiliou@uchsc.edu
Vasilis
V
Vasiliou
Lubna
L
Qamar
Aglaia
A
Pappa
Nickolas A
NA
Sophos
Dennis R
DR
Petersen
D000818:Animals; D000838:Anions; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D003600:Cytosol / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005355:Fibrosis / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism*; D008156:Luciferases / Q000378:metabolism; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism; D051265:NF-E2-Related Factor 1; D051267:NF-E2-Related Factor 2; D051266:Nuclear Respiratory Factor 1; D051264:Nuclear Respiratory Factors; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011808:Quinone Reductases / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D013347:Subcellular Fractions; D013481:Superoxides / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D015854:Up-Regulation; D024483:Vitamin K 3 / Q000494:pharmacology*
D000838:Anions; D004268:DNA-Binding Proteins; D051265:NF-E2-Related Factor 1; D051267:NF-E2-Related Factor 2; C495632:Nfe2l1 protein, rat; C495637:Nfe2l2 protein, rat; D051266:Nuclear Respiratory Factor 1; D051264:Nuclear Respiratory Factors; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53; D013481:Superoxides; D024483:Vitamin K 3; D008156:Luciferases; C041831:NADH dehydrogenase (quinone); D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; D011808:Quinone Reductases