title: Prevention of platelet glycoprotein IIb/IIIa activation by 3,4-methylenedioxy-beta-nitrostyrene, a novel tyrosine kinase inhibitor.
abstract: Binding fibrinogen to activated glycoprotein (GP)IIb/IIIa is the final common pathway of platelet aggregation and has become a successful target for antiplatelet therapy. In the present study, we found that a small chemical compound, 3,4-methyl-enedioxy-beta-nitrostyrene (MNS), exhibited potent and broad-spectrum inhibitory effects on human platelet aggregation caused by various stimulators. Moreover, addition of MNS to human platelets that had been aggregated by ADP caused a rapid disaggregation. We demonstrated that the antiaggregatory activity of MNS is due to inhibition of GPIIb/IIIa activation by measuring the binding amount of PAC-1 in platelets. In contrast, MNS is not a direct antagonist of GPIIb/IIIa, because MNS did not affect fibrinogen binding to fixed ADP-stimulated platelets. By investigating how MNS inhibits GPIIb/IIIa activation, we found that MNS potently inhibited the activity of tyrosine kinases (Src and Syk) and prevented protein tyrosine phosphorylation and cytoskeletal association of GPIIb/IIIa and talin, but it had no direct effects on protein kinase C, Ca2+ mobilization, Ca2+-dependent enzymes (myosin light chain kinase and calpain), and arachidonic acid metabolism, and it did not affect the cellular levels of cyclic nucleotides. Therefore, MNS represents a new class of tyrosine kinase inhibitor that potently prevents GPIIb/IIIa activation and platelet aggregation without directly affecting other signaling pathways required for platelet activation. Because MNS inhibits GPIIb/IIIa functions in a manner different from GPIIb/IIIa antagonists, this feature may provide a new strategy for treatment of platelet-dependent thrombosis.
authors.affiliation: Graduate Institute of Natural Products, Kaohsiung Medical University, 100 Shih-Chuan 1st Rd., Kaohsiung, 807, Taiwan.
authors.forename: Wei-Ya
authors.initials: WY
authors.lastname: Wang
authors.forename: Yang-Chang
authors.initials: YC
authors.lastname: Wu
authors.forename: Chin-Chung
authors.initials: CC
authors.lastname: Wu
mesh_terms: D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000378:metabolism; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism; D004148:Dioxolanes / Q000494:pharmacology; D004341:Drug Evaluation; D006801:Humans; D015394:Molecular Structure; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D009712:Nucleotides, Cyclic / Q000378:metabolism; D019007:P-Selectin / Q000378:metabolism; D051966:Phospholipase C gamma / Q000378:metabolism; D010974:Platelet Aggregation / Q000187:drug effects*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D015398:Signal Transduction; D016608:Talin / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology; D013931:Thromboxanes / Q000378:metabolism
chemical_list: C514815:3,4-methylenedioxy-beta-nitrostyrene; D004148:Dioxolanes; D009712:Nucleotides, Cyclic; D019007:P-Selectin; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D016608:Talin; D013931:Thromboxanes; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D009219:Myosin-Light-Chain Kinase; D051966:Phospholipase C gamma; D013917:Thrombin; D002154:Calpain; D002118:Calcium