CD40 ligand shedding is regulated by interaction between matrix metalloproteinase-2 and platelet integrin αIIbβ3
CD40 ligand shedding is regulated by interaction between matrix metalloproteinase-2 and platelet integrin αIIbβ3
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DOI：
10.1111/j.1538-7836.2010.03837.x
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发表时间：
2010-06-01
影响因子：
10.4
通讯作者：
Kim, D. -S.
中科院分区：
文献类型：
--
作者：
Choi, W. -S.;Jeon, O. -H.;Kim, D. -S.
背景：循环系统中的CD40配体（CD40L、CD154）主要存在于血小板中，活化血小板表面表达的CD40L随后通过蛋白水解活性裂解生成可溶性CD40L （sCD40L）。然而，在活化血小板中负责CD40L脱落的酶尚未被清楚地确定。我们最近发现基质金属蛋白酶-2 （MMP-2）与整合素α (IIb) β(3)的分子相互作用是增强血小板活化所必需的。目的：阐明mmp -2相关sCD40L释放的生化机制。方法：采用流式细胞术和荧光显微镜分析血小板中MMP-2和CD40L的定位。酶联免疫吸附法测定活化血小板中sCD40L的释放。免疫沉淀和western blotting分析MMP-2与α (IIb) β(3)的结合。利用重组血红素样结构域和MMP-2特异性抑制剂来表征MMP-2的结合性质和催化活性。结果：研究发现，活化的人血小板中sCD40L的有效生成需要MMP-2与α (IIb) β(3)的相互作用。抑制血小板来源的MMP-2活性或抑制酶与整合素的结合显著影响血小板活化和sCD40L的释放。在富含血小板的血浆中也发现MMP-2活性负责生成sCD40L。结论：本研究的结果强烈提示MMP-2与α (IIb) β(3)相互作用，调节暴露在活化的人血小板表面的CD40L的脱落。
Background: CD40 ligand (CD40L, CD154) in the circulatory system is mainly contained in platelets, and surface-expressed CD40L on activated platelets is subsequently cleaved by proteolytic activity to generate soluble CD40L (sCD40L). However, the enzyme responsible for the shedding of CD40L in activated platelets has not been clearly identified yet. We have recently found that molecular interaction of matrix metalloproteinase-2 (MMP-2) with integrin alpha(IIb)beta(3) is required for the enhancement of platelet activation. Objectives: To elucidate the biochemical mechanism of MMP-2-associated sCD40L release. Methods: Localization of MMP-2 and CD40L in platelets was analyzed by flow cytometry and fluorescence microscopy. The release of sCD40L from activated platelets was measured by enzyme-linked immunosorbent assay. MMP-2 binding to alpha(IIb)beta(3) was analyzed by immunoprecipitation and western blotting. Recombinant hemopexin-like domain and MMP-2-specific inhibitor were used to characterize the nature of MMP-2 binding and catalytic activity. Results: It was revealed that interaction of MMP-2 with alpha(IIb)beta(3) is required for effective production of sCD40L in activated human platelets. Platelet activation and release of sCD40L were significantly affected by inhibition of platelet-derived MMP-2 activity or by inhibition of binding between the enzyme and the integrin. It was also found in platelet-rich plasma that MMP-2 activity is responsible for generating sCD40L. Conclusions: The results presented here strongly suggest that MMP-2 interacts with alpha(IIb)beta(3) to regulate the shedding of CD40L exposed on the surfaces of activated human platelets.