Pharmacodynamics of Biased G Protein-Coupled Receptor Agonism

偏向 G 蛋白偶联受体激动的药效学

• 批准号: 9916766
• 负责人: LOUIS M LUTTRELL
• 金额: $ 37.38万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9916766
• 关键词: Agonist; Arrestins; Behavior; Bioinformatics; Biological; Biological Assay; Biological Process; Cells; Clinical effectiveness; Data Set; Development; Engineering; Fingerprint; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; GTP-Binding Proteins; In Vitro; Laboratories; Ligands; Link; Measures; Mediating; Methods; Molecular; Molecular Conformation; Nature; Pathway interactions; Pattern; Pharmacodynamics; Physiological; Proteomics; Receptor Activation; Regulation; Signal Pathway; Signal Transduction; Specific qualifier value; Structure; System; Techniques; Therapeutic; Tissues; base; desensitization; design; drug development; experience; in vivo; insight; novel; novel therapeutics; receptor; response; screening; side effect; targeted treatment; tool; transcriptomics

While G protein-coupled receptor (GPCR) drug development has traditionally focused on conventional agonism and antagonism, the newer paradigms of `pluridimensional efficacy' and `functional selectivity' recognize that GPCRs mediate biological effects through both classical G protein-dependent and novel G protein-independent signaling networks, and that ligand structure can `bias' signaling by stabilizing active receptor states in different proportions than the native ligand. Such `biased agonists' are novel entities that possess pathway-selective efficacy, in effect creating new receptors with distinct signaling profiles driven by ligand structure. The promise of biased agonism resides with this ability to engender mixed agonist/antagonist effects in vivo and produce biological effects not attainable with conventional agonists or antagonists. Recent experience has shown, however, that biased agonist effects in vivo are often unpredictable, indicating that key gaps exist in our understanding of biased agonism that stand as barriers to the rational design of novel GPCR targeted therapeutics. Progress in our laboratory over the past five years has provided some mechanistic insights into the apparent idiosyncratic nature of ligand bias. We have shown that ligand structure can specify distinct `activation modes' in effectors, causing the same effector to perform different functions and even dissociating classically linked effector functions, e.g. arrestin-dependent GPCR desensitization and signaling. As these `unbalanced' signals propagate, we find that biased agonists can sometimes produce opposite effects on downstream signaling networks than conventional agonists. As a result, the in vivo transcriptomic `fingerprint' of biased and conventional agonists are largely non-overlapping at the level of regulated signaling pathways and biological processes. Fortunately, in the case of arrestin pathway-selective bias it appears that the arrestin-dependent signaling repertoire is sufficiently restricted that the transcriptomic effects are relatively conserved between tissues and focused on regulation only a few basic biological processes. The overall objectives of our future research are: 1) to understand the mechanisms underlying biased GPCR signaling at the molecular level so as to better predict how different forms of ligand bias will change the cellular response to GPCR activation; and, 2) to determine how biased efficacy measured in engineered `screening' cell systems relates to the biological responses they produce in physiologically relevant cells and tissues. As in the past, we will employ a full range of cell-based techniques to characterize the impact of ligand structure on receptor and effector conformation and function, as well as systems level bioinformatics analysis of proteomic and transcriptomic datasets to determine how specific patterns of efficacy impact the behavior of primary cells and the influence of cell background on the response. Completion of this project will help to develop a rational framework for relating in vitro ligand efficacy to the in vivo actions of arrestin pathway-selective biased GPCR ligands, providing information and tools that are critical to the development of novel biased therapeutics.

虽然 G 蛋白偶联受体 (GPCR) 药物开发传统上侧重于传统药物 激动和对抗，“多维功效”和“功能选择性”的新范式 认识到 GPCR 通过经典 G 蛋白依赖性和新型 G 蛋白介导生物效应 独立于蛋白质的信号网络，并且配体结构可以通过稳定活性来“偏向”信号传导 受体状态与天然配体的比例不同。这种“偏向激动剂”是新颖的实体， 具有途径选择性功效，实际上创造了具有不同信号传导特征的新受体 配体结构。偏向激动的希望在于产生混合激动剂/拮抗剂的能力 体内作用并产生常规激动剂或拮抗剂无法达到的生物效应。最近的 然而，经验表明，体内偏向激动剂效应往往是不可预测的，这表明关键 我们对偏向激动的理解存在差距，这成为合理设计新型 GPCR 的障碍 靶向治疗。我们实验室在过去五年中取得的进展提供了一些机制 深入了解配体偏差的明显特殊性质。我们已经证明配体结构可以指定 效应器中不同的“激活模式”，导致同一效应器执行不同的功能，甚至 解离经典关联的效应器功能，例如抑制蛋白依赖性 GPCR 脱敏和信号转导。 随着这些“不平衡”信号的传播，我们发现有偏差的激动剂有时会产生相反的效果 与传统激动剂相比，对下游信号网络的影响更大。因此，体内转录组 偏向激动剂和传统激动剂的“指纹”在调节信号水平上基本上不重叠 途径和生物过程。幸运的是，在抑制蛋白途径选择性偏差的情况下，似乎 抑制蛋白依赖性信号传导库受到足够的限制，因此转录组效应相对较小 组织之间保守，仅专注于调节一些基本的生物过程。整体 我们未来研究的目标是：1）了解偏向 GPCR 信号传导的潜在机制 分子水平，以便更好地预测不同形式的配体偏向将如何改变细胞的反应 GPCR 激活； 2) 确定在工程“筛选”细胞系统中如何测量有偏差的功效 与它们在生理相关细胞和组织中产生的生物反应有关。和过去一样， 我们将采用全方位的基于细胞的技术来表征配体结构对受体的影响 和效应器构象和功能，以及蛋白质组和蛋白质组的系统级生物信息学分析 转录组数据集，以确定特定的功效模式如何影响原代细胞的行为和 细胞背景对反应的影响。该项目的完成将有助于制定合理的 将体外配体功效与抑制蛋白通路选择性偏向 GPCR 的体内作用联系起来的框架 配体，提供对开发新型偏向疗法至关重要的信息和工具。