靶向代谢型谷氨酸受体8变构调节位点的3DShapeSim药物发现与镇痛作用研究

Neuropathic pain is chronic pain conditions caused by a primary neurological damage or dysfunction that is estimated to inflence 6-8% of populations around the world. Only seven drugs are approved for treating neuropathic pain and they are associated with limited efficacy and significant side effects. It is extremely important to develop new drugs for this disease. Literatures have demonstrated group III metabotropic glutamate receptor 8 (mGluR8) plays an important role in signal transduction of pain in pathological conditions and my previous work also have identified a positive allosteric modulator.Based on these findings, this project aims to establish a multi-level screening system targeting allosteric site of mGluR8. 3DShapeSim is used first to identify the small molecule cluser with similar three-dimensional shape with known mGluR8 allosteric modulator. Mutiple computational approaches are integrated to evaluate the binding affinity and blood brain barrier permeability of these molecules. Application of this screening system will result in mGluR8 allosteric modulators with high activity and excellent drug-like properties, which then can be developed as lead compounds for the treatment of neuropathic pain. We also will investigate selectivity accross mGluR family and elucidate possible mechanisms of action for these modulators, which can be used as tool drugs to study neurological functions of mGluR8 and would show great clinical potential.

神经病理性疼痛是一种由神经系统原发损害或功能障碍引起的影响全世界约6-8%人口的慢性疼痛疾病。目前仅有7种治疗神经病理性疼痛药物被批准且疗效有限、副作用显著,因此新药开发极为重要。基于III组代谢性谷氨酸受体8(mGluR8）在病理状态下疼痛信息传导的重要作用及申请人前期工作发现的mGluR8正向变构剂，本项目提出一种靶向mGluR8变构调节位点的多层次药物发现策略，从3DShapeSim出发，着重研究具有相似活性形状的分子群，集成多种计算方法评价其与mGluR8受体结合力及血脑屏障通透性，通过体外和疾病动物模型实验平台进一步筛选活性高、类药性佳的mGluR8变构调节剂且验证其体内药效，综合运用分子生物学、药理学方法考察mGluR8变构剂的亚型选择性及镇痛机制。本项目的研究有助于发现成药性高的治疗神经病理性疼痛先导化合物，为mGluR8神经药理学研究提供新的工具药并具有着重要的临床意义。

神经病理性疼痛是一种由神经系统原发损害或功能障碍引起的影响全世界约6-8%人口的慢性疼痛疾病。目前仅有7种治疗神经病理性疼痛药物被批准且疗效有限、副作用显著,因此新药开发极为重要。基于III组代谢性谷氨酸受体8(mGluR8）在病理状态下疼痛信息传导的重要作用，本项目提出一种靶向mGluR8变构调节位点的多层次药物发现策略，从3DShapeSim出发，着重研究具有相似活性形状的分子群，集成多种计算方法评价其与mGluR8受体结合力及血脑屏障通透性。通过同源建模技术构建mGluR8蛋白立体结构分子模型，随后采用分子对接技术，评价了化合物结构库中120，000+个化合物与该模型的结合作用。对接发现的阳性化合物的血脑屏障通透性被多个机器学习模型综合评价，并开展体外验证实验，最后10个化合物进入体外药效实验。在已构建好的mGluR8单转细胞系（CHO-K1-mGluR8）上，基于[35S]GTPγS 测量，发现1个化合物（SN-1）可以影响GTP与mGluR8的结合能力，但该活性是负向调节作用，IC50约为500 nM。在考察了两种给药方式、多个给药浓度后，PNSL动物模型证实SN-1没有体内药效。后续研究发现化合物不能透过血脑屏障，从而不能发挥mGluR8变构调节作用。亚型选择性实验发现SN-1对I组mGluR也有负向调节作用，但Ic50比较高，约为3 microM。给药前后，脑内mGluR蛋白表达量没有变化。本项目的研究为成药性高的治疗神经病理性疼痛先导化合物发现提供一个技术路线，同时提示需要重视血脑屏障透过性研究，特别是靶向脑内表达靶点蛋白的药物发现。