title: iNOS/NO signaling regulates apoptosis induced by glycochenodeoxycholate in hepatocytes.
abstract: Inducible nitric oxide synthase (iNOS) and nitric oxide (NO) can ameliorate apoptosis induced by toxic glycochenodeoxycholate (GCDC) in hepatocytes. However, the underlying molecular mechanisms are not yet understood in detail. This study is to clarify the function of iNOS/NO and its mechanisms during the apoptotic process. The apoptosis was brought about by GCDC in rat primary hepatocytes. iNOS/NO signaling was then investigated. iNOS inhibitor 1400W enhanced the GCDC-induced apoptosis as reflected by caspase-3 activity and TUNEL assay. Exogenous NO regulated the apoptosis subsequent to NO donor S-nitroso-N-acetyl-penicillamine (SNAP) or sodium nitroprusside (SNP). The GCDC-induced apoptosis was decreased with 0.1mM SNAP or 0.15mM SNP, while it was increased with 0.8mM SNAP or 1.2mM SNP. The endogenous iNOS inhibited apoptosis, but the exogenous NO played a dual role during the GCDC-induced apoptosis. There was a potential iNOS/Akt/survivin axis that inhibited the hepatocyte apoptosis in low doses of NO donors. In contrast, high doses of NO donors activated CHOP through p38MAP-kinase (p38MAPK), upregulated TRAIL receptor DR5, and suppressed survivin. Consequently the high doses of NO donors promoted the apoptosis in hepatocytes. Our data suggest that the iNOS/NO signaling can modulate Akt/survivin and p38MAPK/CHOP pathways to mediate the GCDC-induced the apoptosis in hepatocytes. These signaling pathways may serve as targets for therapeutic intervention in cholestatic liver disease.
authors.affiliation: Department of Pediatrics, Rush University Medical Center, Chicago, IL 60612, United States. kewei_wang@rush.edu
authors.forename: Kewei
authors.initials: K
authors.lastname: Wang
authors.forename: John J
authors.initials: JJ
authors.lastname: Brems
authors.forename: Richard L
authors.initials: RL
authors.lastname: Gamelli
authors.forename: Ai-Xuan
authors.initials: AX
authors.lastname: Holterman
mesh_terms: D000578:Amidines / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D001596:Benzylamines / Q000494:pharmacology; D015153:Blotting, Western; D002478:Cells, Cultured; D024202:Electrophoretic Mobility Shift Assay; D004791:Enzyme Inhibitors / Q000378:metabolism; D005999:Glycochenodeoxycholic Acid / Q000494:pharmacology*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009569:Nitric Oxide / Q000494:pharmacology*; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009599:Nitroprusside / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D015398:Signal Transduction; D000077022:Survivin; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000578:Amidines; D001596:Benzylamines; C516989:Birc5 protein, rat; D004791:Enzyme Inhibitors; D007093:Imidazoles; D008869:Microtubule-Associated Proteins; C104820:N-(3-(aminomethyl)benzyl)acetamidine; D011725:Pyridines; D000077022:Survivin; D009599:Nitroprusside; D009569:Nitric Oxide; D005999:Glycochenodeoxycholic Acid; D026423:S-Nitroso-N-Acetylpenicillamine; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D051057:Proto-Oncogene Proteins c-akt; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580