Application of high-throughput screening to identify a novel αIIb-specific small-molecule inhibitor of αIIbβ3-mediated platelet interaction with fibrinogen
Application of high-throughput screening to identify a novel αIIb-specific small-molecule inhibitor of αIIbβ3-mediated platelet interaction with fibrinogen
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DOI：
10.1182/blood-2007-08-105544
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发表时间：
2008-02-01
期刊：
影响因子：
20.3
通讯作者：
Coller, Barry S.
中科院分区：
文献类型：
--
作者：
Blue, Robert;Murcia, Marta;Coller, Barry S.
小分子α IIb β 3拮抗剂通过跨越α IIb中的D224和β 3中的MIDAS金属离子竞争性阻断配体结合。它们不可避免地诱导受体的构象变化，这可能具有不期望的后果。为了鉴定具有新结构的α IIb β 3拮抗剂，我们测试了33264种小分子在16 μ M下抑制洗涤血小板与固定化纤维蛋白原粘附的能力。总共有102种化合物表现出50%或更高的抑制作用，其中一种（化合物1，265 g/mol）抑制ADP诱导的血小板聚集（IC 50：13 +/- 5 μ M）、可溶性纤维蛋白原与mAb AP 5诱导的血小板的结合以及可溶性纤维蛋白原和环状RGD肽与纯化的α IIb β 3的结合。化合物1不影响GPIb、α 2 β 1或其它β 3家族受体α V β 3的功能。分子对接模拟表明，化合物1与α IIb相互作用，而不是β 3。化合物1诱导α IIb配体诱导的结合位点（LIBS）的部分暴露，但不诱导203 LIBS的暴露。将纯化的α IIb β 3短暂暴露于依替巴肽而不是化合物1，增强了纤维蛋白原结合（“引发”）。化合物1提供了通过靶向α IIb而无需受体引发的小分子选择性抑制α IIb β 3的原型。
Small-molecule alpha IIb beta 3 antagonists competitively block ligand binding by spanning between the D224 in alpha IIb and the MIDAS metal ion in beta 3. They variably induce conformational changes in the receptor, which may have undesirable consequences. To identify alpha IIb beta 3 antagonists with novel structures, we tested 33 264 small molecules for their ability to inhibit the adhesion of washed platelets to immobilized fibrinogen at 16 mu M. A total of 102 compounds demonstrated 50% or more inhibition, and one of these (compound 1, 265 g/mol) inhibited ADP-induced platelet aggregation (IC50: 13 +/- 5 mu M), the binding of soluble fibrinogen to platelets induced by mAb AP5, and the binding of soluble fibrinogen and a cyclic RGD peptide to purified alpha IIb beta 3. Compound 1 did not affect the function of GPIb, alpha 2 beta 1, or the other beta 3 family receptor alpha V beta 3. Molecular docking simulations suggest that compound 1 interacts with alpha IIb but not beta 3. Compound 1 induced partial exposure of an alpha IIb ligand-induced binding site (LIBS), but did not induce exposure of 2 03 LIBS. Transient exposure of purified alpha IIb beta 3 to eptifibatide, but not compound 1, enhanced fibrinogen binding ("priming"). Compound 1 provides a prototype for small molecule selective inhibition of alpha IIb beta 3, without receptor priming, via targeting alpha IIb.