Regulation of platelet granule exocytosis by S-nitrosylation

doi:10.1073/pnas.0408310102

Regulation of platelet granule exocytosis by S-nitrosylation

Departments of ^*Comparative Medicine, ^†Pathology, ^‡Medicine, and ^§Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; and ^¶Center for Blood Research and Department of Pathology, Harvard Medical School, Boston, MA 02115

Edited by Louis J. Ignarro, University of California School of Medicine, Los Angeles, CA (received for review November 8, 2004)

Abstract

Nitric oxide (NO) regulates platelet activation by cGMP-dependent mechanisms and by mechanisms that are not completely defined. Platelet activation includes exocytosis of platelet granules, releasing mediators that regulate interactions between platelets, leukocytes, and endothelial cells. Exocytosis is mediated in part by N-ethylmaleimide-sensitive factor (NSF), an ATPase that disassembles complexes of soluble NSF attachment protein receptors. We now demonstrate that NO inhibits exocytosis of dense granules, lysosomal granules, and α-granules from human platelets by S-nitrosylation of NSF. Platelets lacking endothelial NO synthase show increased rolling on venules, increased thrombosis in arterioles, and increased exocytosis in vivo. Regulation of exocytosis is thus a mechanism by which NO regulates thrombosis.

Footnotes

↵ ∥ To whom correspondence should be addressed at: The Johns Hopkins University School of Medicine, 950 Ross Building, 720 Rutland Avenue, Baltimore, MD 21205. E-mail: clowenst{at}jhmi.edu.
Author contributions: C.N.M., R.B.S., W.M.B., and C.J.L. designed research; C.N.M., K.M., K.C., M.Y., and W.B. performed research; C.N.M., J.L.M., W.M.B., and N.F. contributed new reagents/analytic tools; C.N.M., R.J.A.M., and C.J.L. analyzed data; and C.N.M. and C.J.L. wrote the paper.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations: NSF, N-ethylmaleimide-sensitive factor; SNARE, soluble NSF attachment receptor; DEA-NONOate, diethylamine NONOate; VAMP, vesicle-associated membrane protein; SNAP, soluble NSF-attachment protein; PRP, platelet-rich plasma; l-NAME, l-nitroarginine methyl ester; NAC, N-acetylcysteine; ODQ, 1-H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one; eNOS, endothelial NO synthase; TRAP, thrombin receptor-activating peptide.