Laboratorio de Química Medicinal, Centro de Investigaciones en Bionanociencias (CIBION), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires C1425FQD, Argentina.
Instituto de Investigaciones Biotecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de San Martín, San Martín B1650, Argentina.
ACS Infect Dis. 2021 Jun 11;7(6):1503-1518. doi: 10.1021/acsinfecdis.0c00915. Epub 2021 May 28.
The worldwide expansion of chikungunya virus (CHIKV) into tropical and subtropical areas in the last 15 years has posed a currently unmet need for vaccines and therapeutics. The E2-E1 envelope glycoprotein complex binds receptors on the host cell and promotes membrane fusion during CHIKV entry, thus constituting an attractive target for the development of antiviral drugs. In order to identify CHIKV antivirals acting through inhibition of the envelope glycoprotein complex function, our first approach was to search for amenable druggable sites within the E2-E1 heterodimer. We identified a pocket located in the interface between E2 and E1 around the fusion loop. Then, via a structure-based virtual screening approach and in vitro assay of antiviral activity, we identified compound as a specific inhibitor of CHIKV. Through a lead optimization process, we obtained compound that demonstrated increased antiviral activity and low cytotoxicity (EC 1.6 μM, CC 56.0 μM). Molecular dynamics simulations were carried out and described a possible interaction pattern of compound and the E1-E2 dimer that could be useful for further optimization. As expected from target site selection, compound inhibited virus internalization during CHIKV entry. In addition, virus populations resistant to compound included mutation E2-P173S, which mapped to the proposed binding pocket, and second site mutation E1-Y24H. Construction of recombinant viruses showed that these mutations conferred antiviral resistance in the parental background. Finally, compound presents acceptable solubility values and is chemically and enzymatically stable in different media. Altogether, these findings uncover a suitable pocket for the design of CHIKV entry inhibitors with promising antiviral activity and pharmacological profiles.
在过去的 15 年中，基孔肯雅病毒（CHIKV）在热带和亚热带地区的全球扩张，对疫苗和疗法提出了目前尚未满足的需求。包膜糖蛋白 E2-E1 复合物结合宿主细胞上的受体，并在 CHIKV 进入时促进膜融合，因此构成了开发抗病毒药物的有吸引力的靶标。为了鉴定通过抑制包膜糖蛋白复合物功能起作用的 CHIKV 抗病毒药物，我们的第一种方法是在 E2-E1 异二聚体中寻找可成药的适宜位点。我们在融合环周围 E2 和 E1 之间的界面上鉴定出一个口袋。然后，通过基于结构的虚拟筛选方法和体外抗病毒活性测定，我们鉴定出化合物 是 CHIKV 的特异性抑制剂。通过一个先导优化过程，我们得到了化合物 ，它表现出增强的抗病毒活性和低细胞毒性（EC 1.6 μM，CC 56.0 μM）。进行了分子动力学模拟，并描述了化合物 与 E1-E2 二聚体的可能相互作用模式，这可能对进一步优化有用。如预期的靶位选择，化合物 在 CHIKV 进入时抑制病毒内化。此外，对化合物 具有抗性的病毒群体包括突变 E2-P173S，该突变映射到提出的结合口袋，以及第二位点突变 E1-Y24H。重组病毒的构建表明，这些突变在亲本背景中赋予了抗病毒抗性。最后，化合物 具有可接受的溶解度值，并且在不同介质中化学和酶稳定。总之，这些发现揭示了一个适合设计具有有前景的抗病毒活性和药理学特征的 CHIKV 进入抑制剂的合适口袋。
