Zhang H, Nimmer PM, Tahir SK, Chen J, Fryer RM, Hahn KR, Iciek LA, Morgan SJ, Nasarre MC, Nelson R, Preusser LC, Reinhart GA, Smith ML, Rosenberg SH, Elmore SW, Tse C. Bcl-2 family proteins are essential for platelet survival.
Cell Death Differ 2007;
14:943-51. [PMID:
17205078 DOI:
10.1038/sj.cdd.4402081]
[Citation(s) in RCA: 317] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Platelets are relatively short-lived, anucleated cells that are essential for proper hemostasis. The regulation of platelet survival in the circulation remains poorly understood. The process of platelet activation and senescence in vivo is associated with processes similar to those observed during apoptosis in nucleated cells, including loss of mitochondrial membrane potential, caspase activation, phosphatidylserine (PS) externalization, and cell shrinkage. ABT-737, a potent antagonist of Bcl-2, Bcl-X(L), and Bcl-w, induces apoptosis in nucleated cells dependent on these proteins for survival. In vivo, ABT-737 induces a reduction of circulating platelets that is maintained during drug therapy, followed by recovery to normal levels within several days after treatment cessation. Whole body scintography utilizing ([111])Indium-labeled platelets in dogs shows that ABT-737-induced platelet clearance is primarily mediated by the liver. In vitro, ABT-737 treatment leads to activation of key apoptotic processes including cytochrome c release, caspase-3 activation, and PS externalization in isolated platelets. Despite these changes, ABT-737 is ineffective in promoting platelet activation as measured by granule release markers and platelet aggregation. Taken together, these data suggest that ABT-737 induces an apoptosis-like response in platelets that is distinct from platelet activation and results in enhanced clearance in vivo by the reticuloendothelial system.
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