title: Mechanisms of cytokine induced NO-mediated cardiac fibroblast apoptosis.
abstract: This study examined the role of nitric oxide (NO) in cytokine-induced apoptosis in adult cardiac fibroblasts (CFbs). In cultured adult rat CFbs, IL-1beta (5 ng/ml), but not interferon-gamma (10 ng/ml) or tumor necrosis factor-alpha (10 ng/ml), induced inducible NO synthase (iNOS) expression and NO production that was associated with an increase in caspase-3 activity and apoptotic cell death. Apoptotic frequency was reduced by the iNOS inhibitor S-methylisothiourea (3 x 10(-5) M). Apoptosis in response to IL-1beta was attenuated by the caspase-3 inhibitor [Z-Asp-Glu-Val-Asp-fluoromethyl ketone (Z-DVED-FMK)] but not by inhibition of guanylyl cyclase with 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). IL-1beta-induced CFb apoptosis was associated with an increase in p53 and Bax protein expression with no changes in Bcl-2 or Bcl-x(L). Nuclear condensation and fragmentation occurred when isolated nuclei were exposed to an NO donor [Z-1[N-(2-aminoethyl)-N-(2-ammonoethyl)amino]diazen-1-ium-1,2-dioate (DETA-NONOate) 10(-5) M], an effect that was not blocked by the peroxynitrite scavenger Mn(III)tetrakis(4-benzoic acid) porphyrin chloride. Moreover, Mn(III)tetrakis(4-benzoic acid) porphyrin chloride attenuated but did not eliminate IL-1beta-induced CFb apoptosis, indicating that the proapoptotic effect of NO can occur independently of its conversion to peroxynitrite. Our results demonstrate that IL-1beta-induced iNOS expression can trigger NO-dependent apoptosis in adult CFbs, which appears to result from DNA damage and may be mediated by a p53-dependent apoptotic pathway.
authors.affiliation: Division of Cardiology, Department of Medicine, University of Minnesota Health Science Center, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Tian
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Peter B
authors.initials: PB
authors.lastname: Bitterman
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Bache
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006834:Hydrazines / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009603:Nitroso Compounds; D030421:Peroxynitrous Acid / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D006834:Hydrazines; D007375:Interleukin-1; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D016159:Tumor Suppressor Protein p53; C094210:2,2'-(hydroxynitrosohydrazono)bis-ethanamine; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases