title: Potentiation of nitric oxide-induced apoptosis in p53-/- vascular smooth muscle cells.
abstract: The functional role of p53 in nitric oxide (NO)-mediated vascular smooth muscle cell (VSMC) apoptosis remains unknown. In this study, VSMC from p53-/- and p53+/+ murine aortas were exposed to exogenous or endogenous sources of NO. Unexpectedly, p53-/- VSMC were much more sensitive to the proapoptotic effects of NO than were p53+/+ VSMC. Furthermore, this paradox appeared to be specific to NO, because other proapoptotic agents did not demonstrate this differential effect on p53-/- cells. NO-induced apoptosis in p53-/- VSMC occurred independently of cGMP generation. However, mitogen-activated protein kinase (MAPK) pathways appeared to play a significant role. Treatment of the p53-/- VSMC with S-nitroso-N-acetylpenicillamine resulted in a marked activation of p38 MAPK and, to a lesser extent, of c-Jun NH(2)-terminal kinase, mitogen-activated protein kinase kinase (MEK) 1/2, and p42/44 (extracellular signal-regulated kinase, ERK). Furthermore, basal activity of the MEK-p42/44 (ERK) pathway was increased in the p53+/+ VSMC. Inhibition of p38 MAPK with SB-203580 or of MEK1/2 with PD-98059 blocked NO-induced apoptosis. Therefore, p53 may protect VSMC against NO-mediated apoptosis, in part, through differential regulation of MAPK pathways.
authors.affiliation: Department of Surgery, University of Pittsburgh, 677 Scaife Hall, Pittsburgh, PA 15261, USA. kibbemr@msx.upmc.edu
authors.forename: Melina R
authors.initials: MR
authors.lastname: Kibbe
authors.forename: Jianrong
authors.initials: J
authors.lastname: Li
authors.forename: Suhua
authors.initials: S
authors.lastname: Nie
authors.forename: Byung Min
authors.initials: BM
authors.lastname: Choi
authors.forename: Imre
authors.initials: I
authors.lastname: Kovesdi
authors.forename: Alena
authors.initials: A
authors.lastname: Lizonova
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Billiar
authors.forename: Edith
authors.initials: E
authors.lastname: Tzeng
mesh_terms: D000256:Adenoviridae / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001011:Aorta; D017209:Apoptosis / Q000502:physiology*; D002469:Cell Separation; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D020287:In Situ Nick-End Labeling; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D016159:Tumor Suppressor Protein p53; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D020928:Mitogen-Activated Protein Kinases