Structure-based strategy for developing inhibitors of the kidney chloride channel CLC-Ka

ClC(氯离子通道家族)是一种阴离子选择性转运体和通道，广泛存在于 所有的有机体。其中，ClC-KA和ClC-KB是氯离子和水处理所必需的。 肾脏。CLC-KA定位于细长的上升肢，在那里它有助于建立陡峭的溶质 内髓间质中的梯度，驱动肾水重吸收。因此，CLC-KA 是治疗病理性水留(低钠血症)的潜在药物靶点 使高血压、心力衰竭或肝硬变患者的管理复杂化。一种特定的 CLC-KA抑制剂对于验证CLC-KA作为操纵肾脏的药物靶点是非常有价值的 水的排泄。在这个项目中，我们利用最近的突破来开发选择性的CLC-KA 抑制剂。第一个突破是我们发现了BIM1，一种取代的苯并咪唑， 显示对CLC-KA的选择性比其最接近的同系物CLC-Kb高20倍。合成材料 BIM衍生品的可获得性使其非常适合进一步开发。第二 突破是低温电子显微镜的革命，它使高分辨率 具有挑战性的目标的结构确定，包括离子通道。一种分子结构 BIM/ClC-K复合体将识别BIM分子的哪些区域必须保留 效力/选择性，并且可以被修改以改善药代动力学特性。指导原则 这些信息，我们将使用药物化学的方法来开发BIM衍生物 优化的效力、选择性和药代动力学特性。优化的BIM衍生品将是 经体内药效测试。

CLCs (the “Chloride Channel” family) are anion-selective transporters and channels ubiquitous in all organisms. Among them, CLC-Ka and CLC-Kb are essential for Cl– and water handling in the kidney. CLC-Ka is localized to the thin ascending limb, where it helps to establish the steep solute gradient in the inner medullary interstitium that drives renal water reabsorption. As such, CLC-Ka is a potential drug target for treating pathologic water retention (hyponatremia) that frequently complicates the management of patients with hypertension, heart failure, or cirrhosis. A specific CLC-Ka inhibitor would be invaluable for validating CLC-Ka as a drug target for manipulating renal water excretion. In this project, we leverage recent breakthroughs to develop selective CLC-Ka inhibitors. The first breakthrough is our discovery of BIM1, a substituted benzimidazole that displays >20-fold selectivity for CLC-Ka over its closest homolog CLC-Kb. The synthetic accessibility of BIM derivatives makes them well suited for further development. The second breakthrough is the revolution in cryo-electron microscopy, which enables high-resolution structure determination of challenging targets, including ion channels. A molecular structure of the BIM/CLC-K complex will identify which regions of the BIM molecule must be retained for potency/selectivity and which may be modified to improve pharmacokinetic properties. Guided by this information, we will use a medicinal chemistry approach to develop BIM derivatives with optimized potency, selectivity, and pharmacokinetic properties. Optimized BIM derivatives will be tested for in vivo efficacy.