Hydrogen peroxide regulation of endothelial exocytosis by inhibition of N-ethylmaleimide sensitive factor.
Although an excess of reactive oxygen species (ROS) can damage the vasculature, low concentrations of ROS mediate intracellular signal transduction pathways. We hypothesized that hydrogen peroxide plays a beneficial role in the vasculature by inhibiting endothelial exocytosis that would otherwise induce vascular inflammation and thrombosis. We now show that endogenous H(2)O(2) inhibits thrombin-induced exocytosis of granules from endothelial cells. H(2)O(2) regulates exocytosis by inhibiting N-ethylmaleimide sensitive factor (NSF), a protein that regulates membrane fusion events necessary for exocytosis. H(2)O(2) decreases the ability of NSF to hydrolyze adenosine triphosphate and to disassemble the soluble NSF attachment protein receptor complex. Mutation of NSF cysteine residue C264T eliminates the sensitivity of NSF to H(2)O(2), suggesting that this cysteine residue is a redox sensor for NSF. Increasing endogenous H(2)O(2) levels in mice decreases exocytosis and platelet rolling on venules in vivo. By inhibiting endothelial cell exocytosis, endogenous H(2)O(2) may protect the vasculature from inflammation and thrombosis.
Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Kenji
K
Matsushita
Craig N
CN
Morrell
Rebecca J A
RJ
Mason
Munekazu
M
Yamakuchi
Firdous A
FA
Khanday
Kaikobad
K
Irani
Charles J
CJ
Lowenstein
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism*; D005089:Exocytosis / Q000502:physiology*; D025461:Feedback, Physiological / Q000502:physiology; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007249:Inflammation / Q000378:metabolism / Q000517:prevention & control; D046911:Macromolecular Substances / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation / Q000235:genetics; D052066:N-Ethylmaleimide-Sensitive Proteins; D010084:Oxidation-Reduction; D013917:Thrombin / Q000378:metabolism; D013927:Thrombosis / Q000378:metabolism / Q000517:prevention & control; D015854:Up-Regulation / Q000502:physiology; D014652:Vascular Diseases / Q000378:metabolism* / Q000503:physiopathology; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D046911:Macromolecular Substances; D033921:Vesicular Transport Proteins; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; D013917:Thrombin; D052066:N-Ethylmaleimide-Sensitive Proteins; C498733:Nsf protein, mouse; D003545:Cysteine