Toll-like receptor 2 stimulation of platelets is mediated by purinergic P2X1-dependent Ca2+ mobilisation, cyclooxygenase and purinergic P2Y1 and P2Y12 receptor activation
Toll-like receptor 2 stimulation of platelets is mediated by purinergic P2X1-dependent Ca2+ mobilisation, cyclooxygenase and purinergic P2Y1 and P2Y12 receptor activation
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DOI：
10.1160/th09-07-0442
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发表时间：
2010-02-01
影响因子：
6.7
通讯作者：
Bengtsson, Torbjorn
中科院分区：
文献类型：
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作者：
Kalvegren, Hanna;Skoglund, Caroline;Bengtsson, Torbjorn
Toll样受体2(TLR2)识别并响应保守的微生物病原体相关分子模式，表达于血小板表面。此外，最近有研究表明，TLR2/1激动剂Pam(3)CSK(4)能刺激血小板活化。本研究的目的是阐明Pam(3)CSK(4)诱导的血小板聚集和分泌中的重要信号事件。通过分析聚集、ATP分泌、[Ca~(2+)](I)动员和血栓素B_2(TxB(2))的产生，研究了血小板与Pam(3)、CSK(4)和TLR2/6激动剂MALP-2的相互作用。结果表明，Pam(3)、CSK(4)而不是MALP-2可引起[Ca~(2+)](I)升高、TxB(2)生成、致密颗粒分泌和血小板聚集。MALP-2可抑制PAM(3)、CSK(4)诱导的血小板反应。Pam(3)、CSK(4)刺激的血小板的ATP分泌和聚集可被嘌呤能P2X(1)抑制剂MRS 2159、嘌呤能P2Y(1)和P2Y(12)拮抗剂MRS 2179、康瑞尔、磷脂酶C抑制剂U73122、钙离子螯合剂BAPT-AM和阿司匹林所抑制。MRS 2159、阿司匹林和U73122可降低TxB(2)的钙动员，而MRS 2159、阿司匹林和BAPT-AM可拮抗TxB(2)的产生。在研究髓系分化因子-88(MyD88)依赖途径的参与时，我们发现血小板表达MyD88和白介素1受体相关蛋白-1(IRAK-1)，这两种蛋白在TLR信号转导中起重要作用。然而，Pam(3)CSK(4)不能刺激血小板中IRAK-1的快速(10分钟内)磷酸化。结果表明，Pam(3)CSK(4)诱导的血小板聚集和分泌依赖于P2X(1)介导的钙动员、TXA(2)的产生和ADP受体的激活。这项研究的发现进一步支持了血小板在感知细菌成分方面的作用。
Toll-like receptor 2 (TLR2), which recognise and respond to conserved microbial pathogen-associated molecular patterns, is expressed on the platelet surface. Furthermore, it has recently been shown that the TLR2/1 agonist Pam(3)CSK(4) stimulates platelet activation. The aim of the present study was to clarify important signalling events in Pam(3)CSK(4)-induced platelet aggregation and secretion. Platelet interaction with Pam(3)CSK(4) and the TLR2/6 agonist MALP-2 was studied by analysing aggregation, ATP-secretion, [Ca2+](i) mobilisation and thromboxane B2 (TxB(2)) production. The results show that Pam(3)CSK(4) but not MALP-2 induces [Ca2+](i) increase, TxB(2) production, dense granule secretion and platelet aggregation. Preincubation of platelets with MALP-2 inhibited the Pam(3)CSK(4)-induced responses. The ATP-secretion and aggregation in Pam(3)CSK(4)-stimulated platelets was impeded by the purinergic P2X(1) inhibitor MRS 2159, the purinergic P2Y(1) and P2Y(12) antagonists MRS 2179 and cangrelor, the phospholipase C inhibitor U73122, the calcium chelator BAPT-AM and aspirin. The calcium mobilisation was lowered by MRS 2159, aspirin and U73122 whereas the TxB(2) production was antagonised by MRS 2159, aspirin and BAPT-AM. When investigating the involvement of the myeloid differentiation factor-88 (MyD88) -dependent pathway, we found that platelets express MyD88 and interleukin 1 receptor-associated kinase (IRAK-1), which are proteins important in TLR signalling. However, Pam(3)CSK(4) did not stimulate a rapid (within 10 minutes) phosphorylation of IRAK-1 in platelets. In conclusion, the results show that Pam(3)CSK(4)-induced platelet aggregation and secretion depends on a P2X(1)-mediated Ca2+ mobilisation, production of TxA(2) and ADP receptor activation. The findings in this study further support a role for platelets in sensing bacterial components.