Sachpatzidis Aristidis, Benton Benjamin K, Manfredi John P, Wang Hua, Hamilton Andrew, Dohlman Henrik G, Lolis Elias
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
J Biol Chem. 2003 Jan 10;278(2):896-907. doi: 10.1074/jbc.M204667200. Epub 2002 Nov 3.
The chemokine receptor CXCR4 is a co-receptor for T-tropic strains of HIV-1. A number of small molecule antagonists of CXCR4 are in development but all are likely to lead to adverse effects due to the physiological function of CXCR4. To prevent these complications, allosteric agonists may be therapeutically useful as adjuvant therapy in combination with small molecule antagonists. A synthetic cDNA library coding for 160,000 different SDF-based peptides was screened for CXCR4 agonist activity in a yeast strain expressing a functional receptor. Peptides that activated CXCR4 in an autocrine manner induced colony formation. Two peptides, designated RSVM and ASLW, were identified as novel agonists that are insensitive to the CXCR4 antagonist AMD3100. In chemotaxis assays using the acute lymphoblastic leukemia cell line CCRF-CEM, RSVM behaves as a partial agonist and ASLW as a superagonist. The superagonist activity of ASLW may be related to its inability to induce receptor internalization. In CCRF-CEM cells, the two peptides are also not inhibited by another CXCR4 antagonist, T140, or the neutralizing monoclonal antibodies 12G5 and 44717.111. These results suggest that alternative agonist-binding sites are present on CXCR4 that could be screened to develop molecules for therapeutic use.
趋化因子受体CXCR4是HIV-1 T嗜性毒株的共受体。多种CXCR4小分子拮抗剂正在研发中，但由于CXCR4的生理功能，所有这些拮抗剂都可能导致不良反应。为预防这些并发症，变构激动剂作为与小分子拮抗剂联合使用的辅助治疗手段可能具有治疗价值。在表达功能性受体的酵母菌株中，对编码160,000种不同SDF基肽的合成cDNA文库进行CXCR4激动剂活性筛选。以自分泌方式激活CXCR4的肽可诱导集落形成。两种肽，命名为RSVM和ASLW，被鉴定为对CXCR4拮抗剂AMD3100不敏感的新型激动剂。在使用急性淋巴细胞白血病细胞系CCRF-CEM的趋化性分析中，RSVM表现为部分激动剂，ASLW表现为超级激动剂。ASLW的超级激动剂活性可能与其无法诱导受体内化有关。在CCRF-CEM细胞中，这两种肽也不受另一种CXCR4拮抗剂T140或中和单克隆抗体12G5和44717.111的抑制。这些结果表明，CXCR4上存在其他激动剂结合位点，可对其进行筛选以开发治疗用分子。
