Mitochondria generated nitric oxide protects against permeability transition via formation of membrane protein S-nitrosothiols.
Mitochondria generated nitric oxide (NO) regulates several cell functions including energy metabolism, cell cycling, and cell death. Here we report that the NO synthase inhibitors (L-NAME, L-NNA and L-NMMA) administered either in vitro or in vivo induce Ca2+-dependent mitochondrial permeability transition (MPT) in rat liver mitochondria via a mechanism independent on changes in the energy state of the organelle. MPT was determined by the occurrence of cyclosporin A sensitive mitochondrial membrane potential disruption followed by mitochondrial swelling and Ca2+ release. In in vitro experiments, the effect of NOS inhibitors was dose-dependent (1 to 50 microM). In addition to cyclosporin A, L-NAME-induced MPT was sensitive to Mg2+ plus ATP, EGTA, and to a lower degree, to catalase and dithiothreitol. In contrast to L-NAME, its isomer D-NAME did not induce MPT. L-NAME-induced MPT was associated with a significant decrease in both the rate of NO generation and the content of mitochondrial S-nitrosothiol. Acute and chronic in vivo treatment with L-NAME also promoted MPT and decreased the content of mitochondrial S-nitrosothiol. SNAP (a NO donor) prevented L-NAME mediated MPT and reversed the decrease in the rate of NO generation and in the content of S-nitrosothiol. We propose that S-nitrosylation of critical membrane protein thiols by NO protects against MPT.
Departamento de Fisiologia e Biofísica, Universidade Estadual de Campinas, UNICAMP, Campinas, SP, Brazil.
Ana Catarina R
AC
Leite
Helena C F
HC
Oliveira
Fabiane L
FL
Utino
Rafael
R
Garcia
Luciane C
LC
Alberici
Mariana P
MP
Fernandes
Roger F
RF
Castilho
Aníbal E
AE
Vercesi
D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000187:drug effects / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D008933:Mitochondrial Swelling / Q000187:drug effects; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D026403:S-Nitrosothiols / Q000378:metabolism*
D004791:Enzyme Inhibitors; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D020030:Nitric Oxide Donors; D026403:S-Nitrosothiols; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester