C-Phycocyanin, a Very Potent and Novel Platelet Aggregation Inhibitor from Spirulina platensis
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- 作者：George Hsiao ; Po-Hsiu Chou ; Ming-Yi Shen ; Duen-Suey Chou ; Chien-Huang Lin ; and Joen-Rong Sheu
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：October 5, 2005
- 年：2005
- 卷：53
- 期：20
- 页码：7734 - 7740
- 全文大小：162K
- 年卷期：v.53,no.20(October 5, 2005)
- ISSN：1520-5118
文摘
The aim of this study was to systematically examine the inhibitory mechanisms of C-phycocyanin(C-PC), one of the major phycobiliproteins of Spirulina platensis (a blue-green alga), in plateletactivation. In this study, C-PC concentration-dependently (0.5-10 nM) inhibited platelet aggregationstimulated by agonists. C-PC (4 and 8 nM) inhibited intracellular Ca2+ mobilization and thromboxaneA2 formation but not phosphoinositide breakdown stimulated by collagen (1 
g/mL) in human platelets.In addition, C-PC (4 and 8 nM) markedly increased levels of cyclic GMP and cyclic GMP-inducedvasodilator-stimulated phosphoprotein (VASP) Ser157 phosphorylation. Rapid phosphorylation of aplatelet protein of Mw 47 000 (P47), a marker of protein kinase C activation, was triggered by phorbol-12,13-dibutyrate (150 nM). This phosphorylation was markedly inhibited by C-PC (4 and 8 nM). Inaddition, C-PC (4 and 8 nM) markedly reduced the electron spin resonance (ESR) signal intensity ofhydroxyl radicals in collagen (1 g/mL)-activated platelets. The present study reports on a novel andvery potent (in nanomolar concentrations) antiplatelet agent, C-PC, which is involved in the followinginhibitory pathways: (1) C-phycocyanin increases cyclic GMP/VASP Ser157 phosphorylation andsubsequently inhibits protein kinase C activity, resulting in inhibition of both P47 phosphorylationand intracellular Ca2+ mobilization, and (2) C-PC may inhibit free radicals (such as hydroxyl radicals)released from activated platelets, which ultimately inhibits platelet aggregation. These results stronglyindicate that C-PC appears to represent a novel and potential antiplatelet agent for treatment of arterialthromboembolism.Keywords: Blue-green alga; C-phycocyanin; thromboxane A2; protein kinase C; cyclic GMP; vasodilator-stimulated phosphoprotein; hydroxyl radical
g/mL) in human platelets.In addition, C-PC (4 and 8 nM) markedly increased levels of cyclic GMP and cyclic GMP-inducedvasodilator-stimulated phosphoprotein (VASP) Ser157 phosphorylation. Rapid phosphorylation of aplatelet protein of Mw 47 000 (P47), a marker of protein kinase C activation, was triggered by phorbol-12,13-dibutyrate (150 nM). This phosphorylation was markedly inhibited by C-PC (4 and 8 nM). Inaddition, C-PC (4 and 8 nM) markedly reduced the electron spin resonance (ESR) signal intensity ofhydroxyl radicals in collagen (1 g/mL)-activated platelets. The present study reports on a novel andvery potent (in nanomolar concentrations) antiplatelet agent, C-PC, which is involved in the followinginhibitory pathways: (1) C-phycocyanin increases cyclic GMP/VASP Ser157 phosphorylation andsubsequently inhibits protein kinase C activity, resulting in inhibition of both P47 phosphorylationand intracellular Ca2+ mobilization, and (2) C-PC may inhibit free radicals (such as hydroxyl radicals)released from activated platelets, which ultimately inhibits platelet aggregation. These results stronglyindicate that C-PC appears to represent a novel and potential antiplatelet agent for treatment of arterialthromboembolism.Keywords: Blue-green alga; C-phycocyanin; thromboxane A2; protein kinase C; cyclic GMP; vasodilator-stimulated phosphoprotein; hydroxyl radical