Negative allosteric modulators for bradykinin B1 receptors

缓激肽（BK）B1受体（BKB 1 R）活性涉及广泛的病理状况，包括 水肿、炎症、哮喘、慢性疼痛、血管病变、神经病变、肥胖症、糖尿病性视网膜病变和癌症。 然而，这些受体的拮抗剂将预期具有很大的治疗效用，尽管几种拮抗剂都是有效的。 BKB 1 R拮抗剂已进入临床试验，但没有一种药物成功进入II期。BKB 1 R是 通常在大多数组织中不表达，除非暴露于炎症介质，并且当表达时， 高水平的组成型（激动剂非依赖性）受体活性。虽然BKB 1 R失败的原因 在临床试验中的拮抗剂尚未报道，很可能是高水平的组成活性的拮抗剂， BKB 1 R不能被标准拮抗剂降低，是导致疗效失败的原因。减少 组成型受体活性需要具有反向激动剂活性的正构配体或负变构配体 调节器不幸的是，仅有的已知BKB 1 R的正构反向激动剂非常弱， 没有减少组成性活性的变构调节剂。这一项目的前提是， 组成型BKB 1 R活性是治疗有效拮抗剂的重要组分。这个目标 该项目旨在鉴定通过拮抗BKB 1 R功能来降低BKB 1 R功能的新型化合物， 内源性激动剂（des-Arg 10-胰激肽）和降低组成型BKB 1 R活性。这种效应可 用正构反向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，以鉴定减少激动剂激活的化合物， 在HEK细胞中表达的人BKB 1 R的组成型活性。在目标1b中，我们将筛选来自目标的命中 1a以消除具有非特异性作用或改变BKB 2 R活性的化合物。在目标1c中，化合物 目标1b中的化合物将进行严格的化学测试（例如Schild分析实验），以确定变构 与正构作用机制的对比。由于NAM具有优于正构配体的几个优点，包括 特异性、安全性和微调受体功能的能力沿着降低组成型受体活性， 我们将优先考虑NAM而不是正构反向激动剂。最后，在目标1d中，我们将确认BKB 1 NAM 当BKB 1 R使用人肺天然表达时， 微血管内皮细胞这项工作将提供初步数据和候选分子， 推进IND赋能研究。虽然这个项目是高风险的， 降低人BKB 1 R的组成型活性的负变构调节剂是非常需要的。

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.