Activation of matrix metalloproteinases by peroxynitrite-induced protein S-glutathiolation via disulfide S-oxide formation

Oxidative stress may cause tissue injury through activation of the precurso rs of matrix metalloproteinase (proMMPs). In this study, we observed glutat hione (GSH)-dependent proMMP activation induced by peroxynitrite, a potent oxidizing agent formed during inflammatory processes. Peroxynitrite strongl y activated all three types of purified human proMMPs (proMMP-1, -8, and -9 ) in the presence of similar concentrations of GSH. Of the potential reacti on products between peroxynitrite and GSH, only S-nitroglutathione (GSNO(2) ) caused proMMP activation. Extensive S-glutathiolation of the proMMP prote in occurred during activation of proMMP by peroxynitrite and GSH, as shown by radiolabeling studies with [S-35]GSH or [H-3]GSH. Evidence of appreciabl e S-glutathiolation persisted even after dithiothreitol and protein-denatur ing treatment, however, suggesting that some S-glutathiolation did not occu r through formation of simple mixed disulfide. Matrix-assisted laser-desorp tion ionization-time-of-flight mass spectrometry indicated that not only pe roxynitrite plus GSH but also synthetic GSNO(2) produced dithiothreitol-res istant S-glutathiolation of the synthetic peptide PRCGVPD, which is a well conserved Cys-containing sequence of the propeptide autoinhibitory domain o f proMMPs. PRCGVPD S-glutathiolation is presumed to be formed through gluta thione disulfide S-oxide (GS(O)SR), based on the m/z 1064. Our results illu strate a unique mechanism of oxidative proMMP activation and oxidative tiss ue injury during inflammation.