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

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