Regulation by mitochondrial superoxide and NADPH oxidase of cellular formation of nitrated cyclic GMP: potential implications for ROS signalling

• Published in: Biochemical journal Vol. 441; no. 2; p. 719
• Main Authors: Ahmed, Khandaker Ahtesham, Sawa, Tomohiro, Ihara, Hideshi, Kasamatsu, Shingo, Yoshitake, Jun, Rahaman, Md Mizanur, Okamoto, Tatsuya, Fujii, Shigemoto, Akaike, Takaaki
• Format: Journal Article
• Language: English
• Published: England 15.01.2012
• Subjects: 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt - pharmacology; Animals; Cell Line, Tumor; Cyclic GMP - analogs & derivatives; Cyclic GMP - pharmacology; Hydrogen Peroxide - metabolism; Lipopolysaccharides - pharmacology; Mitochondria - drug effects; Mitochondria - metabolism; NADPH Oxidases - metabolism; Nitrogen Oxides - metabolism; Peroxynitrous Acid - metabolism; Rats; Reactive Nitrogen Species - metabolism; Reactive Oxygen Species - metabolism; Rotenone - pharmacology; Signal Transduction - physiology; Superoxides - metabolism
• ISSN: 1470-8728
• DOI: 10.1042/BJ20111130

8-Nitro-cGMP (8-nitroguanosine 3',5'-cyclic monophosphate) is a nitrated derivative of cGMP, which can function as a unique electrophilic second messenger involved in regulation of an antioxidant adaptive response in cells. In the present study, we investigated chemical and biochemical regulatory mechanisms involved in 8-nitro-cGMP formation, with particular focus on the roles of ROS (reactive oxygen species). Chemical analyses demonstrated that peroxynitrite-dependent oxidation and myeloperoxidase-dependent oxidation of nitrite in the presence of H2O2 were two major pathways for guanine nucleotide nitration. Among the guanine nucleotides examined, GTP was the most sensitive to peroxynitrite-mediated nitration. Immunocytochemical and tandem mass spectrometric analyses revealed that formation of 8-nitro-cGMP in rat C6 glioma cells stimulated with lipopolysaccharide plus pro-inflammatory cytokines depended on production of both superoxide and H2O2. Using the mitochondria-targeted chemical probe MitoSOX Red, we found that mitochondria-derived superoxide can act as a direct determinant of 8-nitro-cGMP formation. Furthermore, we demonstrated that Nox2 (NADPH oxidase 2)-generated H2O2 regulated mitochondria-derived superoxide production, which suggests the importance of cross-talk between Nox2-dependent H2O2 production and mitochondrial superoxide production. The results of the present study suggest that 8-nitro-cGMP can serve as a unique second messenger that may be implicated in regulating ROS signalling in the presence of NO.