PharmaCenter Bonn, Pharmaceutical Institute, University of Bonn, Pharmaceutical & Medicinal Chemistry, An der Immenburg 4, Bonn, 53121, Germany.
Orion Pharma, Orion Corporation, Tengströminkatu 8, FI-20360 Turku, and Orionintie 1A, Espoo, FI- 02200, Finland.
Purinergic Signal. 2024 Dec;20(6):645-656. doi: 10.1007/s11302-024-10005-2. Epub 2024 May 25.
P2X4 receptors are ATP-gated cation channels that were proposed as novel drug targets due to their role in inflammation and neuropathic pain. Only few potent and selective P2X4 receptor antagonists have been described to date. Labeled tool compounds suitable for P2X4 receptor binding studies are lacking. Here, we present a novel allosteric P2X4 receptor antagonist possessing high potency in the low nanomolar range. We describe its tritium-labeling resulting in the P2X4-selective radiotracer [H]PSB-OR-2020 with high specific activity (45 Ci/mmol; 1.67 TBq/mmol). A radioligand binding assay was developed using human embryonic kidney (HEK293) cell membranes recombinantly expressing the human P2X4 receptor. Competition binding studies with structurally diverse P2X4 receptor antagonists revealed different allosteric binding sites indicating that the new class of P2X4 receptor antagonists, to which PSB-OR-2020 belongs, interacts with an unprecedented allosteric site. [H]PSB-OR-2020 may become a useful tool for research on P2X4 receptors and for promoting drug development.
P2X4 受体是 ATP 门控阳离子通道，由于其在炎症和神经病理性疼痛中的作用，被提议作为新的药物靶点。迄今为止，仅描述了少数几种强效和选择性的 P2X4 受体拮抗剂。缺乏适合 P2X4 受体结合研究的标记工具化合物。在这里，我们提出了一种新型的变构 P2X4 受体拮抗剂，在低纳摩尔范围内具有高效力。我们描述了其氚标记，导致具有高比活度（45 Ci/mmol；1.67 TBq/mmol）的 P2X4 选择性放射性示踪剂 [H]PSB-OR-2020。使用在人胚肾（HEK293）细胞膜中重组表达人 P2X4 受体的方法开发了放射性配体结合测定法。与结构多样的 P2X4 受体拮抗剂的竞争结合研究表明存在不同的变构结合位点，表明 PSB-OR-2020 所属的新型 P2X4 受体拮抗剂与前所未有的变构结合位点相互作用。[H]PSB-OR-2020 可能成为研究 P2X4 受体和促进药物开发的有用工具。
