基于mHNTX-III-Nav1.7相互作用复合物的Nav1.7多肽抑制剂优化改造

The voltage-gated sodium channel Nav1.7 is currently one of the most promising analgesic targets, and has received close attention from biological, medical and pharmaceutical industries. Due to the large sequence similarity with other sodium channel subtypes, the existing Nav1.7 inhibitors are not selective and have side effects, which limits their further application. In view of this, it is still a hot concept and difficult point in improving the selectivity of Nav1.7 inhibitors. In our previous study, we obtained a Nav1.7 inhibitor mHNTX-III with weak affinify to other subtypes except for Nav1.6 channel, and the mechanism research showed that differences exist in the interaction sites of mHNTX-III on Nav1.6 and Nav1.7. This project uses mHNTX-III as a template to design and chemically synthesize a series of mutants based on the interaction complex of HNTX-III docking with Nav1.7 or Nav1.6 by computer-assisted design in order to obtain highly active and specific inhibitor. Animal pain models were used to evaluate analgesic activity. This study lays a foundation for obtaining high-efficiency and low-toxic lead molecules for novel analgesics.

电压门控钠通道Nav1.7是目前最具潜力的镇痛药物靶点之一，受生物、医学和制药行业密切关注。由于与其他钠通道亚型的序列相似度较大，现有抑制剂选择性不强，副作用较大，限制了其进一步应用开发。鉴于此，提高Nav1.7抑制剂的选择性仍是当前研究热点和难点。我们前期研究得到了一个Nav1.7抑制剂mHNTX-III, 除Nav1.6以外，对其他钠通道亚型活性较弱，机制研究显示mHNTX-III在Nav1.6和Nav1.7上的作用位点存在差异性。本课题以mHNTX-III为模板，借助计算机辅助设计，基于mHNTX-III与Nav1.7和Nav1.6通道的docking复合物，设计和化学合成一系列突变体，以期获得高活性和专一性的改造分子，并利用疼痛动物模型验证其镇痛活性，为获得高效低毒的新型镇痛药物先导分子奠定基础。

Nav1.7是疼痛治疗的一个绝佳靶点，其专一性抑制剂具有很好的镇痛药物开发前景。由于与其他钠通道亚型的序列相似度较大，现有抑制剂选择性不强，副作用较大，限制了其进一步应用开发。本项目以mHNTX-III为模板，构建了mHNTX-III/hNav1.7 VSD-II复合物分子对接模型，该模型表明mHNTX-III可能是通过静电相互作用和疏水相互作用与hNav1.7相互作用的两亲性分子；基于分子对接模型，选择两者相互作用面及其附近的氨基酸残基进行突变，并将活力提升的突变体进行组合，最终获得活性增强最大突变体H4（K0G1-P18K-A21L-V, IC50 0.007 ± 0.001 uM）,其效价提高了30倍，并且对Nav1.4和Nav1.5的选择性提升1000倍以上；构建H4/hNav1.7 VSD-II复合物分子对接模型，该模型表明H4与hNav1.7亲和力和结合力的提升可能是通过增强的静电相互作用和疏水相互作用的结果。H4在急性、慢性炎症性疼痛模型和神经性疼痛模型中也表现出强大的镇痛作用。综上所述，本项目成功的获得改造分子H4，该分子可作为新型镇痛药物先导分子应用于临床前研究。