Small molecule receptor agonists and antagonists of CCR3 provide insight into mechanisms of chemokine receptor activation.
Small molecule receptor agonists and antagonists of CCR3 provide insight into mechanisms of chemokine receptor activation.
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DOI：
10.1074/jbc.m703255200
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发表时间：
2007-09-21
影响因子：
4.8
通讯作者：
Pease, James E
中科院分区：
文献类型：
--
作者：
Wise, Emma L;Duchesnes, Cecile;da Fonseca, Paula C A;Allen, Rodger A;Williams, Timothy J;Pease, James E
趋化因子受体CCR3是嗜酸性粒细胞高度表达的信号，是对嗜酸性粒细胞趋化因子家族结合的反应，趋化因子家族在变态反应性疾病中上调。因此，CCR3阻断作为治疗过敏性疾病的一种可能的治疗方法是令人感兴趣的。我们以前已经描述了一种CCR1和CCR3的双特异性拮抗剂UCB35625，它被认为与CCR1的跨膜残基Y41、Y113和E287相互作用，这些残基都在CCR3中保守。在这里，我们表明表达CCR3结构Y113A和E287Q的细胞对UCB35625的拮抗不敏感，也表现出对CCL11/eoaxin反应的趋化性受损，这表明这些残基对拮抗剂结合和受体激活都是重要的。此外，Y113残基突变为丙氨酸，使拮抗剂UCB35625转变为CCR3激动剂。小分子文库筛选鉴定出一种新的CCR3特异性激动剂CH0076989。这能够激活嗜酸性粒细胞和表达野生型CCR3和缺乏CCR3氨基末端的CCR1：CCR3嵌合受体的转染体，表明CCR3的这个区域不是CH0076989结合所必需的。Y41、Y113和E287残基的突变支持了与CCR3跨膜螺旋的直接相互作用，导致CH0076989活性完全丧失，表明该化合物模拟了CCL11的激活。我们的结论是，CCR3的激动剂和拮抗剂似乎都占据了跨膜螺旋束中的重叠位置，这表明趋化因子受体的激动剂和拮抗剂之间存在细微的区别。
Chemokine receptor CCR3 is highly expressed by eosinophils and signals in response to binding of the eotaxin family of chemokines, which are upregulated in allergic disorders. Consequently, CCR3 blockade is of interest as a possible therapeutic approach for the treatment of allergic disease. We have described previously a bi-specific antagonist of CCR1 and CCR3 named UCB35625, which was proposed to interact with the transmembrane residues Y41, Y113 and E287 of CCR1, all of which are conserved in CCR3. Here, we show that cells expressing the CCR3 constructs Y113A and E287Q are insensitive to antagonism by UCB35625 and also exhibit impaired chemotaxis in response to CCL11/Eotaxin suggesting that these residues are important for antagonist binding and also receptor activation. Furthermore, mutation of the residue Y113 to alanine was found to turn the antagonist UCB35625 into a CCR3 agonist. Screens of small molecule libraries identified a novel specific agonist of CCR3 named CH0076989. This was able to activate eosinophils and transfectants expressing both wild-type CCR3 and a CCR1:CCR3 chimaeric receptor lacking the CCR3 amino-terminus, indicating that this region of CCR3 is not required for CH0076989 binding. A direct interaction with the transmembrane helices of CCR3 was supported by mutation of the residues Y41, Y113 and E287 which resulted in complete loss of CH0076989 activity, suggesting that the compound mimics activation by CCL11. We conclude that both agonists and antagonists of CCR3 appear to occupy overlapping sites within the transmembrane helical bundle, suggesting a fine line between agonism and antagonism of chemokine receptors.