靶向EcR新型广谱蜕皮激动剂的设计、合成与活性研究

The hormonal action of 20E is exerted through activation of the ecdysone receptor (EcR), an invertebrate nuclear receptor responsible for transcriptional regulation of molting. Based on this mode of action, ecdysone agonists targeting EcR have been developed as insect growth regulators (IGRs), which are pesticides for control of harmful arthropods. The applicant has identified several promising EcR agonists with broader spectrum of insecticidal activity and novel chemical structures by virtual screening and biological assays. In order to take the influences of protein flexibility for EcR on the virtual screening into a full consideration, the project plans to develop a virtual screening strategy based on multiple receptor conformations by integrating the predictions from molecular docking and MM/GBSA binding free energy decomposition through machine-learning approaches. The well-validated integrated screening strategy is employed to screen large compound libraries. The candidate compounds are submitted to molecular dynamics simulations and binding free energy calculations. According to the results of binding free energy calculations and structural clustering, some potential EcR agonists will be chosen for biological testing. The goal of the project is to identify promising EcR agonists with good activity, broad spectrum and novel scaffolds, aiming at the development of new pesticides for combating pest.

蜕皮激素受体EcR（ecdysone receptor）通过与内源蜕皮激素结合调控昆虫的蜕皮、变态和繁殖。蜕皮激动剂竞争性结合EcR，持续存在诱导产生致死性蜕皮，并且EcR仅存在于无脊椎动物体内，对哺乳动物安全，是设计和开发新型绿色杀虫剂的重要靶标。申请人利用虚拟筛选结合活性评价已成功发现了多个结构新颖且具有较好结合活性和广谱杀虫活性的蜕皮激动剂。本研究项目拟在申请人前期研究的基础上，充分考虑EcR蛋白柔性对虚拟筛选结果的影响，采用机器学习方法构建基于靶标多构象及MM/GBSA结合自由能分解的整合虚拟筛选模型，并利用构建的模型进行多层级高精度的虚拟筛选，结合有机合成、离体及活体杀虫活性测试发现活性好、作用谱广、结构新颖的蜕皮激动剂先导，为新型绿色杀虫剂的开发奠定坚实的基础。

蜕皮激素受体（ecdysone receptor，EcR）是核受体家族的一员，与其他核受体相似，都具有N端转录激活域、DNA结合域、铰链区和配体结合域。蜕皮激动剂通过与EcR配体结合域结合，调控基因表达，诱导产生致死性蜕皮，并且EcR仅存在于无脊椎动物体内，对哺乳动物安全，是设计和开发新型绿色杀虫剂的重要靶标。本项目在前期工作的基础上，首先发展针对EcR的高精度MIEC-SVM个性化虚拟筛选模型及自由能预测方法；然后采用发展的模型和方法，并结合离体及活体杀虫活性测试对申请人前期发现的一个具有全新骨架结构的蜕皮激动剂（VS14）进行结构优化，并总结其定量构效关系。在本项目的资助下，共发表SCI研究论文7篇。本项目将为先导化合物的发现以及新型绿色杀虫剂的开发奠定坚实的基础。