Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK.
Medicines Discovery Institute, Cardiff University, Cardiff, UK.
Neuropharmacology. 2019 Oct;157:107674. doi: 10.1016/j.neuropharm.2019.107674. Epub 2019 Jun 24.
Identifying novel small-molecule P2X1 and P2X4 ligands with sub-type specificity and high-affinity remains a pharmacological challenge. Here we use computational methods, electrophysiology and fluorescent microplate assays to screen for ligand candidates acting at these receptors. Modelling and docking identified 80 compounds for testing at P2X4 receptors, and 20 of these showed >50% inhibition in fluorescence-based assays, making them appealing for further SAR studies. Confirmation of activity by two-electrode voltage clamp, followed by their elaboration resulted in only minor improvements in potency, with the highest IC being 295 μM. Testing on P2X1 receptors, resulted in a series of biguanide compounds that yielded a maximum IC of 100 μM, but no consistent SAR could be found. Potencies of established antagonists gave expected results, although the measured potencies varied between techniques and no antagonism could be found for compounds such as paroxetine, carbamazepine, 9(10H)-acridanone, acridinol and phenoxazine-type heterocycles. This study highlights the challenge of identifying P2X4 and P2X1 ligands and suggests that a combination of complimentary approaches is needed if we are to be confident of ligand activities at these receptors.
鉴定具有亚型特异性和高亲和力的新型小分子 P2X1 和 P2X4 配体仍然是一个药理学挑战。在这里，我们使用计算方法、电生理学和荧光微孔板测定法来筛选作用于这些受体的配体候选物。建模和对接确定了 80 种用于测试 P2X4 受体的化合物，其中 20 种在基于荧光的测定中显示出 >50%的抑制作用，这使它们成为进一步 SAR 研究的诱人目标。通过双电极电压钳对活性进行确认，然后对其进行阐述，结果仅使效力略有提高，最高 IC 为 295 μM。在 P2X1 受体上进行测试，得到了一系列双胍化合物，其最大 IC 为 100 μM，但未发现一致的 SAR。已建立的拮抗剂的效力给出了预期的结果，尽管在技术之间测量的效力有所不同，并且无法发现某些化合物（如帕罗西汀、卡马西平、9(10H)-吖啶酮、吖啶醇和吩嗪型杂环）具有拮抗作用。本研究强调了鉴定 P2X4 和 P2X1 配体的挑战，并表明如果我们要对这些受体的配体活性有信心，需要结合互补的方法。
