title: PGE1-induced NO reduces apoptosis by D-galactosamine through attenuation of NF-kappaB and NOS-2 expression in rat hepatocytes.
abstract: Prostaglandin E1 (PGE1) reduces cell death in experimental and clinical liver dysfunction. We have previously shown that PGE1 preadministration protects against NO-dependent cell death induced by D-galactosamine (D-GalN) through a rapid increase of nuclear factor kappaB (NF-kappaB) activity, inducible NO synthase (NOS-2) expression, and NO production. The present study investigates whether PGE1-induced NO was able to abolish NF-kappaB activation, NOS-2 expression, and apoptosis elicited by D-GalN. Rat hepatocytes were isolated following the classical method of collagenase perfusion of liver. PGE1 (1 micromol/L) was administered 2 hours before D-GalN (5 mmol/L) in primary culture rat hepatocytes. PGE1 reduced inhibitor kappaBalpha degradation, NF-kappaB activation, NOS-2 expression, and apoptosis induced by D-GalN. The administration of an inhibitor of NOS-2 abolished the inhibitory effect of PGE1 on NF-kappaB activation and NOS-2 expression in D-GalN-treated hepatocytes. Transfection studies using different plasmids corresponding to the NOS-2 promoter region showed that D-GalN and PGE1 regulate NOS-2 expression through NF-kappaB during the initial stage of hepatocyte treatment. PGE1 was able to reduce the promoter activity induced by D-GalN. In addition, a NO donor reduced NOS-2 promoter activity in transfected hepatocytes. In conclusion, administration of PGE1 to hepatocytes produces low levels of NO, which inhibits its own formation during D-GalN-induced cell death through the attenuation of NF-kappaB-dependent NOS-2 expression. Therefore, a dual role for NO in PGE1-treated D-GalN-induced toxicity in hepatocytes is characterized by a rapid NO release that attenuates the late and proapoptotic NOS-2 expression.
authors.affiliation: Unidad de Investigación, Unidad Clínica Aparato Digestivo, Hospital Universitario Reina Sofía, Córdoba, Spain. emilio.siendones.exts@juntadeandalucia.es
authors.forename: Emilio
authors.initials: E
authors.lastname: Siendones
authors.forename: Dalia
authors.initials: D
authors.lastname: Fouad
authors.forename: María José M
authors.initials: MJ
authors.lastname: Díaz-Guerra
authors.forename: Manuel
authors.initials: M
authors.lastname: de la Mata
authors.forename: Lisardo
authors.initials: L
authors.lastname: Boscá
authors.forename: Jordi
authors.initials: J
authors.lastname: Muntané
mesh_terms: D000527:Alprostadil / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology; D025461:Feedback, Physiological / Q000187:drug effects / Q000502:physiology; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D005688:Galactosamine / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D022781:Hepatocytes / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D020672:I-kappa B Proteins / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D011401:Promoter Regions, Genetic; D051381:Rats; D017208:Rats, Wistar
chemical_list: D016207:Cytokines; D005343:Fibrinolytic Agents; D020672:I-kappa B Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606206:Nfkbia protein, rat; D000072000:NF-KappaB Inhibitor alpha; D009569:Nitric Oxide; D005688:Galactosamine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D000527:Alprostadil