Endogenous forms of ATP-ATP4-and MgATP2--orchestrate distinct pathophysiological signaling via biased activation of P2X3 receptors

• 成果类型: Article
• 署名作者: Wang, Jin; Guan, Li; Wang, Ting-Ting; Xie, Tang-Xuan; Lin, Yi-Yu; Sun, Meng-Yang; Wang, Dong-Ping; Zhang, Xue; Bian, Yu-Jing; Yue, Chen -Xi; Ding, Bei-Bei; Ma, Xue-Fei; Yu, Ye
• 署名单位: China Pharmaceutical University; China Pharmaceutical University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2504688122
• 发表日期: 2025-12-16
• 页码: e2504688122
• 关键词: ion channel; biased activation; P2X receptors; allosteric modulation; cough; EXTRACELLULAR ATP; ganglion neurons; channels; mechanism; reveals; pain

摘要

P2X receptors, a family of ATP-activated ion channels, encompass subtypes P2X1-7, which are expressed in both homo-and heterotrimeric forms across various tissues. These receptors play crucial roles in pathophysiological processes such as synaptic transmission, nociception, cough, and taste perception. Extracellular ATP exists as both MgATP2-and ATP4-, with P2X3 responding to both. The evolutionary rationale for two nearly identical ligands and their distinct signaling potential remains unclear. While previous structural studies suggest a uniform ATP recognition mechanism for two endogenous ATP forms, we propose that MgATP2-and ATP4-activate P2X3 through distinct mechanisms, leading to differential physiological and pathological outcomes. Using mutagenesis, voltage-clamp fluorometry, and small molecule interventions, we identify divergent interactions of ATP4-and MgATP2-with P2X3, despite binding to the same orthosteric pocket. In P2rx3D158A/D158A transgenic mice, which selectively impair MgATP2-activation, we find that MgATP2-modulates ammonia-induced cough frequency without affecting complete Freund's adjuvant-induced inflammatory pain or sweet taste preference. P2rx3-/- mice show deficits in all three responses. The allosteric inhibitor aurintricarboxylic acid selectively modulates ATP4-and MgATP2-effects, resulting in distinct antitussive and analgesic outcomes in vivo. These findings uncover a mechanism of P2X3 activation by its endogenous ligands, diverging from previous structural models and resembling the biased activation mechanisms observed in G-protein-coupled receptors, offering insights for P2X3-targeted therapeutics.