Molecular mechanism underlying the subtype-selectivity of competitive inhibitor NF110 and its distinct potencies in human and rat P2X3 receptors  

作　　者：Bin Li Jin Wang Xiaoyang Cheng Yan Liu Yang Yang Xiaona Yang Changrun Guod Youya Niu Peng Cao Xiangyang Lu Michael X.Zhu Yun Tian Ye Yu 

机构地区：[1]College of Biosdence and Biotechnology.Hunan Agricultural University,Changsha 410128,China [2]State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources,School of Chemistry and Pharmaceutical Science,Guangxi Normal University,Guilin 541004,China [3]Department of Pharmacology and Chemical Biology,Institute of Medical Sciences,Shanghai Jiao Tong University School of Medicine,Shanghai 200025,China [4]School of Basic Medicine and Clinical Pharmacy,China Pharmaceutical University,Nanjing 210009,China [5]Department of Cell Biology and Genetics,Hunan University of Medicine,Huaihua 418000,China [6]Hospital of Integrated Traditional Chinese and Western Medicine,Nanjing University of Chinese Medicine,Nanjing 210023,China

出　　处：《Science Bulletin》2018年第24期1616-1625,共10页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(31570832);the National Program on Key Basic Research Project of China(2014CB9103000/02);Science and Technology Department of Hunan Province(2018RS3086);National Postdoctoral Program for Innovative Talents(BX201700306);China Postdoctoral Science Foundation(2018M632127);the Hunan Provincial Natural Science Foundation(2017JJ2198,2018JJ1012);Guangxi Funds for Distinguished Experts

摘　　要：P2X receptors are a family of extracellular ATP-gated trimeric cation channels that is widely distributed in human tissues. Quite some drug candidates targeting P2X receptors have entered into preclinical or main phases of clinical trials, but many of them failed due to low subtype-selectivity or species differences in pharmacological activities between human and experimental animals. Here, we identified the distinct inhibitory efficacies of NF110, a competitive inhibitor, between the rat(rP2X3) and human(hP2X3) P2X3 receptors. We demonstrated that this difference is determined by two amino acids located in the dorsal fin(DF) domain of P2X3 receptors. As revealed by mutagenesis, metadynamics, and covalent modification, NF110-mediated rP2X3 inhibition may be through a filling in the cavity formed by the DF,left flipper(LF) and lower body(LB) to partially, rather than fully, occupy the ATP-binding pocket.Moreover, substitution of residues located in the DF and/or LF domains of the rP2X2 receptor, a NF110-insensitive subtype, with the equivalent amino acids of rP2X3, bestowed the sensitivity of rP2X2 to NF110. The critical roles of the DF and LF domains in channel gating of P2X and low conservativity in residue sequences of those two domains raise the possibility that small molecules differentially interacting with the residues of the DF and LF domains of different P2X receptors may modulate channel's activity in a subtype-selective manner. However, the possible species-specificity of P2X inhibitors/modulators makes it more complex when interpreting the preclinical data into clinical researches.Nevertheless, our data provide new insights into the subtype-selectivity of competitive inhibitors and their distinct potencies in the human and experimental animals, both of which are extremely important in the drug discovery of P2X receptors.P2X receptors are a family of extracellular ATP-gated trimeric cation channels that is widely distributed in human tissues. Quite some drug candidates targeting P2X receptors have entered into preclinical or main phases of clinical trials, but many of them failed due to low subtype-selectivity or species differences in pharmacological activities between human and experimental animals. Here, we identified the distinct inhibitory efficacies of NF110, a competitive inhibitor, between the rat(rP2X3) and human(hP2X3) P2X3 receptors. We demonstrated that this difference is determined by two amino acids located in the dorsal fin(DF) domain of P2X3 receptors. As revealed by mutagenesis, metadynamics, and covalent modification, NF110-mediated rP2X3 inhibition may be through a filling in the cavity formed by the DF,left flipper(LF) and lower body(LB) to partially, rather than fully, occupy the ATP-binding pocket.Moreover, substitution of residues located in the DF and/or LF domains of the rP2X2 receptor, a NF110-insensitive subtype, with the equivalent amino acids of rP2X3, bestowed the sensitivity of rP2X2 to NF110. The critical roles of the DF and LF domains in channel gating of P2X and low conservativity in residue sequences of those two domains raise the possibility that small molecules differentially interacting with the residues of the DF and LF domains of different P2X receptors may modulate channel's activity in a subtype-selective manner. However, the possible species-specificity of P2X inhibitors/modulators makes it more complex when interpreting the preclinical data into clinical researches.Nevertheless, our data provide new insights into the subtype-selectivity of competitive inhibitors and their distinct potencies in the human and experimental animals, both of which are extremely important in the drug discovery of P2X receptors.

关 键 词：P2X RECEPTORS COMPETITIVE inhibitors NF110 Species-specificity Subtype-selectivity 

分 类 号：N[自然科学总论]