Structure-Guided Analysis of Mechanisms of AT1R Functions

 描述（由申请人提供）：众所周知，AngII 1型受体（AT 1 R）是正常心血管生理学的主要调节因子。在多种疾病中，由于AngII诱导细胞中的异常生长、粘附、迁移和炎性基因表达，AT 1 R的慢性刺激导致器官损伤。AT 1 R阻滞剂（ARB）可有效控制高血压，但由于机制不明，其预防器官损害的疗效差异很大。许多实验室致力于阐明多效性AT 1 R信号转导过程的分子基础。我们的研究重点是AT 1 R的结构、构象和药理学机制。我们是第一个在AT 1 R中显示配体非依赖性和有偏信号传导的人，导致了AT 1 R功能子集的配体调节的概念。我们最近阐明了ARB结合的人AT 1 R的第一个3D结构，这是开始这种抗高血压药物靶点的基于结构的研究的重要一步。有了这些新的知识，我们将解决尚未解决的问题，包括：（i）如何临床使用的药物靶向AT 1 R的功能性疗效是由不同的配体亚口袋内的受体？(ii)一个假定的细丝蛋白-A结合基序嵌入AT 1 R如何调节细胞骨架动力学和细胞粘附特性？(iii)AT 1 R天然存在的结构变异改变了AT 1 R功能激活和调节的哪些方面？我们的初步研究提供了关于以下方面的见解：（i）影响ARB不同疗效的AT 1 R-配体亚口袋;（ii）血管紧张素II诱导的细丝蛋白与AT 1 R的结合，这可能是导致粘附依赖性细胞功能的新途径;以及（iii）人群中天然存在的人AT 1 R变体的可能结构效应。本申请的具体目标是：（目的1）检验以下假设：临床实践中结构不同的ARB的疗效由AT 1 R 3D结构中发现的不同配体子口袋决定。(Aim 2）验证AngII诱导的AT 1 R与细丝蛋白的相互作用受新的蛋白质-蛋白质相互作用机制调节的假设。(Aim 3）检验在人群研究中报道的AT 1 R变体改变功能结构域之间的偶联的假设。我们将在临床前研究中使用最先进的分子，生物物理，细胞生物学和体内技术，以促进我们对AT 1 R生物学长期未解决问题的理解。我们的发现很容易转化为临床，并可能促进新疗法的发展。

 DESCRIPTION (provided by applicant): The AngII type 1 receptor (AT1R) is widely known to be the master regulator of normal cardiovascular physiology. In a variety of diseases chronic stimulation of AT1R causes organ damage due to AngII-induced abnormal growth, adhesion, migration and inflammatory gene expression in cells. AT1R blockers (ARBs) effectively control hypertension but their efficacy in preventing organ damage varies widely due to unknown mechanism. Efforts have been made in several laboratories to elucidate the molecular basis of pleotropic AT1R signaling process. We have focused our research on structure, conformation and pharmacological mechanisms governing AT1R. We were the first to show ligand-independent and biased signaling in AT1R, leading to the concept of ligand modulation of subset of AT1R functions. We have recently elucidated first 3D-structure of an ARB-bound human AT1R, as an important step for beginning structure-based studies of this antihypertensive drug-target. With this new knowledge, we will address unresolved questions including: (i) how functional efficacy of clinically used drugs targeting AT1R is determined by different ligand sub-pockets within the receptor? (ii) How does a putative filamin-A binding motif embedded in AT1R operates in regulating cytoskeletal dynamics and cell adhesion properties? (iii) What aspect of activation and regulation of AT1R functions is altered by naturally occurring structural variations in AT1R? Our preliminary studies provide insight regarding (i) AT1R-ligand sub-pockets influencing differential efficacies of ARBs; (ii) AngII-induced engagement of filamin by AT1R which may be a novel pathway leading to adhesion- dependent cell functions; and (iii) possible structural effects of human AT1R variants naturally occurring in population. Our specific goals for this application are: (Aim 1) to test the hypothesis that efficacy of structuraly different ARBs in clinical practice is determined by different ligand sub-pockets found in the AT1R 3D-structure. (Aim 2) to test the hypothesis that AngII-induced AT1R interaction with filamin is regulated by a novel protein- protein interaction mechanism. (Aim 3) to test the hypothesis that AT1R variants reported in human population studies alter coupling between functional domains. We will use state-of-the-art molecular, biophysical, cell biology and in vivo techniques in our preclinical studies to advance our understanding of long unresolved issues in AT1R biology. Our findings are easily translatable to the clinic and may facilitate the development of novel therapeutics.