Negative allosteric modulators for bradykinin B1 receptors

缓激肽(BK)B1受体(BKB1R)的活性与多种病理条件有关，包括 浮肿、炎症、哮喘、慢性疼痛、血管病变、神经病变、肥胖、糖尿病视网膜病变和癌症。 然而，这些受体的拮抗剂有望具有巨大的治疗作用，尽管有几种 BKB1R拮抗剂已经进入临床试验，没有一种成功地从第二阶段出现。 通常在大多数组织中不表达，除非接触炎性介质，当表达时， 高水平的结构性(非激动剂)受体活性。尽管BKB1R失败的原因 拮抗剂在临床试验中还没有报道，很可能是由于高水平的构造性活性 BKB1R是疗效失败的原因，标准拮抗剂不能减少BKB1R。减少 构成受体的活性需要具有反向激动剂活性的正构配体或负变构配体 调整器。不幸的是，唯一已知的BKB1R的正构体反向激动剂非常弱，而且有 没有降低结构性活性的变构调节剂。这个项目的前提是减少 结构性BKB1R活性是治疗有效的拮抗剂的重要组成部分。这样做的目的是 项目是寻找通过对抗BKB1R功能来降低BKB1R功能的新化合物 内源性激动剂(DES-Arg10-Kallidin)和降低结构性BKB1R活性。这种效果可以是 用正构逆激动剂或负变构调节剂(NAM)获得。在目标1a中，我们建议 筛选约170,000个小分子的文库，以识别减少激动剂激活的和 人BKB1Rs在HEK细胞中表达的构筑活性在目标1b中，我们将筛选来自目标的点击数 消除具有非特异性作用或改变BKB2R活性的化合物。在目标1c中，化合物 从Aim 1b开始，将进行严格的药理学测试(例如SChild分析实验)，以确定变构 而不是整形外科的作用机制。由于NaMS与正构体配体相比有几个优点，包括 特异性、安全性和微调受体功能的能力以及降低结构性受体活性的能力， 我们将优先考虑NAMS而不是正构体反向激动剂。最后，在Aim 1D中，我们将确认BKB1 NAMS 当BKB1R在人肺中自然表达时，反向激动剂的作用与预期一致 微血管内皮细胞。这项工作将提供所需的初步数据和候选分子 前进到支持IND的研究。虽然这个项目风险很高，但鉴定是一流的 降低人BKB1Rs构成活性的负变构调节剂是非常可取的。

Bradykinin (BK) B1 receptor (BKB1R) activity is involved in a wide range of pathological conditions including edema, inflammation, asthma, chronic pain, vasculopathy, neuropathy, obesity, diabetic retinopathy and cancer. Antagonists of these receptors would be expected to be of great therapeutic utility, however, although several BKB1R antagonists have entered clinical trials, none have emerged successfully from Phase II. BKB1Rs are generally not expressed in most tissues unless exposed to inflammatory mediators and when expressed, have a high level of constitutive (agonist-independent) receptor activity. Although the reasons for the failure of BKB1R antagonists in clinical trials have not been reported, it is likely that the high level of constitutive activity of the BKB1R, which is not reduced by standard antagonists, is responsible for efficacy failures. Reduction of constitutive receptor activity requires an orthosteric ligand with inverse agonist activity or a negative allosteric regulator. Unfortunately, the only known orthosteric inverse agonists for the BKB1R are very weak and there are no allosteric regulators that reduce constitutive activity. The premise underlying this project is that reduction of constitutive BKB1R activity is an important component of a therapeutically effective antagonist. The goal of this project is to identify novel compounds that reduce BKB1R function by both antagonizing the endogenous agonist (des-Arg10-kallidin) and reducing constitutive BKB1R activity. This effect can be obtained with an orthosteric inverse agonist or a negative allosteric modulator (NAM). In Aim 1a, we propose to screen a library of ~170,000 small molecules to identify compounds that reduce agonist-activated and constitutive activity of the human BKB1Rs expressed in HEK cells. In Aim 1b, we will screen hits from Aim 1a to eliminate compounds that have non-specific effects or that alter BKB2R activity. In Aim 1c, compounds from Aim 1b will be rigorously tested pharmacologically (e.g. Schild analysis experiments) to identify allosteric versus orthosteric mechanisms of action. As NAMs have several advantages over orthosteric ligands, including specificity, safety and the ability to fine-tune receptor function along with reducing constitutive receptor activity, we will prioritize NAMs over orthosteric inverse agonists. Finally, in Aim 1d we will confirm that the BKB1 NAMs and inverse agonists function as expected when BKB1Rs are naturally expressed using human lung microvascular endothelial cells. This work will provide the preliminary data and candidate molecules needed to move forward to IND-enabling studies. Although this project is high risk, the identification of first-in-class negative allosteric regulators that reduce constitutive activity of human BKB1Rs is highly desirable.