Extracellular S-nitrosoglutathione, but not S-nitrosocysteine or N(2)O(3), mediates protein S-nitrosation in rat spinal cord slices.
There is evidence that protein S-nitrosothiols (PrSNOs) accumulate in inflammatory demyelinating disorders like multiple sclerosis and experimental allergic encephalomyelitis. However, very little is known regarding the mechanism by which PrSNOs are formed in target cells. The present study compares the ability of potential intercellular mediators of nitrosative damage including S-nitrosoglutathione (GSNO), S-nitrosocysteine and N(2)O(3) to induce protein S-nitros(yl)ation in the spinal cord, a CNS region that is commonly affected in multiple sclerosis and experimental allergic encephalomyelitis. The results clearly demonstrate that while all three NO-donors cause S-nitrosation of proteins in cell-free systems, only GSNO is a viable S-nitrosating agent in rat spinal cord slices. Generation of PrSNOs with GSNO occurs by S-transnitrosation as the process was not inhibited by either the NO-scavenger rutin or the N(2)O(3)-scavenger azide. Contrary to other cell types, nerve cells incorporate intact GSNO and neither functional l-amino acid transporters nor cell-surface thiols are required. We also found that there is a restricted number of proteins available for S-nitrosation, even at high, non-physiological concentrations of GSNO. These proteins are highly concentrated in mitochondria and mitochondria-rich subcellular compartments. This study is relevant to those CNS disorders characterized by excessive nitric oxide production.
Romero
Jorge M
JM
Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA.
Bizzozero
Oscar A
OA
D000818:Animals; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D045604:Extracellular Fluid / Q000378:metabolism; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology; D008297:Male; D024101:Mitochondrial Proteins / Q000378:metabolism; D009103:Multiple Sclerosis / Q000378:metabolism / Q000503:physiopathology; D009187:Myelitis / Q000378:metabolism / Q000503:physiopathology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D015538:Nitrosation; D009924:Organ Culture Techniques; D018384:Oxidative Stress / Q000502:physiology*; D051381:Rats; D026361:Reactive Nitrogen Species / Q000378:metabolism; D026422:S-Nitrosoglutathione / Q000378:metabolism* / Q000494:pharmacology; D026403:S-Nitrosothiols / Q000378:metabolism*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*; D013463:Sulfuric Acid Esters / Q000378:metabolism
D016166:Free Radical Scavengers; D024101:Mitochondrial Proteins; D009419:Nerve Tissue Proteins; D009566:Nitrates; D026361:Reactive Nitrogen Species; D026403:S-Nitrosothiols; D013463:Sulfuric Acid Esters; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; C021315:S-nitrosocysteine; D003545:Cysteine