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Nitric oxide (NO) preconditioning protects endothelial cells against SNP‐induced apoptosis via the hsp90‐sGC pathway.
Author(s) -
Antonova Galina,
Snead Connie,
Antonov Alexander,
Venema Richard C,
Catravas John D
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a230-b
Subject(s) - apoptosis , sodium nitroprusside , nitric oxide , chemistry , poly adp ribose polymerase , blot , tunel assay , pharmacology , cell , microbiology and biotechnology , biology , biochemistry , polymerase , dna , organic chemistry , gene
Large (pathological) amounts of NO induce cell injury, whereas low (physiological) NO concentrations often ameliorate cell injury. We tested the hypotheses that pretreatment of endothelial cells with low concentrations of NO would prevent the apoptosis induced by high NO concentrations ( preconditioning ) and that the mechanisms of this protective effect may involve sGC activation and hsp90/sGC complex formation. Apoptosis, induced in bovine aortic endothelial cells exposed to 4mM sodium nitroprusside (SNP) for 8 hours, was abolished by 24 hour pretreatment with either 0.1 mM SNP or 0.1mÌ 8‐Br‐cGMP. In controls, the ratio of apoptotic cells/total cells (% ± SE, estimated from the presence of chromatin condensation) was 4.3 ± 0.6%; after exposure to 4 mM SNP the apoptotic cell ratio increased to 28 ± 4.9%, but preconditioned cells maintained an apoptotic cell ration of 3.3 ± 0.55. Similar results were obtained by Western blotting analysis of cleaved poly ADP‐ribose polymerase (PARP). The protective effect of NO preconditioning ‐ but not the injurious effect of 4mM SNP ‐ was abolished by the sGC activity inhibitor, (0.3μM) and was mimicked by the cGMP analog, 8‐Br‐cGMP (0.1mM). Increased assoication and expression of sGC and hsp90 after NO preconditioning were observed by confocal microscopy and western blotting. We conclude that preconditioning with a low dose of NO donor prevents apoptosis via the hsp90/sGC pathway. These mechanisms may play a role in the protective effects of NO‐generating drugs from injurious stimuli. (Supported by HL070214 and HL66993)