Structural mechanism of integrin-mediated TGF-b activation

整合素介导的TGF-b激活的结构机制

• 批准号: 10407522
• 负责人: Yifan Cheng
• 金额: $ 73.79万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-04 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10407522
• 关键词: Adaptor Signaling Protein; Address; Airway Fibrosis; Anabolism; Architecture; Binding; Biochemical; Biological Assay; Cell surface; Cells; Chronic; Chronic Obstructive Pulmonary Disease; Clinical; Complex; Cryoelectron Microscopy; Crystallization; Data; Diffuse; Diffusion; Epithelial; Event; Exposure to; Fibrosis; Funding; Goals; Human; Immune; Inflammation; Inflammatory; Integrins; Lead; Location; Lung; Lung diseases; Mediating; Mediator of activation protein; Mesenchymal; Methods; Modeling; Molecular Conformation; Mutation; Pathologic; Pathology; Peptides; Primates; Process; Pulmonary Fibrosis; Regulation; Risk; Rodent; Sentinel; Series; Signal Transduction; Structure; Toxic effect; Transforming Growth Factor beta; Transforming Growth Factor beta Receptors; airway inflammation; arm; base; chronic inflammatory lung disease; clinical development; cytokine; design; effective therapy; flexibility; improved; in vivo; inflammatory lung disease; integrin alphavbeta8; particle; receptor; receptor binding; therapeutic target

Summary/Abstract: TGF-Beta drives the fibroinflammatory processes that leads to lung and airway fibrosis. The long-term goal of this project is to acquire a deep understanding of the regulation of TGF-Beta activity to develop new strategies and treatments for fibrosing lung disease. There are few effective therapies to treat chronic fibrosing and inflammatory diseases of the lung. The cytokine TGF-Beta is a central mediator of fibrosis and pathologic inflammation and is a potential therapeutic target in fibrosing lung disease. However, the practical utility of targeting TGF-Beta itself or its receptors is limited by risk of toxicities seen in rodents, primates and humans. More specific methods to target the fibroinflammatory effects of TGF-Beta are highly desirable. A promising method to more specifically target local effects of TGF-Beta is to target its “activation” since it is always produced in a latent form (L-TGF-Beta) that must be activated in order to function. Another feature of L-TGF-Beta that could facilitate more specific targeting is that it is covalently bound to specific cell surfaces by GARP. L-TGF-Beta binding to the integrin alphavBeta8 is essential for TGF-Beta activation in vivo. For the alphavBeta8 activation mechanism, as well as all others, it has long been assumed that TGF-Beta must be released from LAP so that free TGF-Beta can diffuse and bind its receptors on target cells. Based on recent structural data obtained using single particle electron cryomicroscopy (cryo-EM), we have recently proposed a new model whereby alphavBeta8 can bind to L-TGF-Beta on cells presenting the L-TGF-Beta/GARP complex and induce signaling without release and diffusion of TGF-Beta. Here in three aims, we address three critical questions concerning this new model of L-TGF-Beta activation. (1) Which flexible domains of L-TGF-Beta of the alphavBeta8/L-TGF-Beta/GARP ternary complex shield TGF-Beta from its receptors? (2) Is flexibility of L-TGF-Beta induced by binding to alphavBeta8 necessary to mediate TGF-Beta activation? (3) Do TGF-Beta receptors (TGF-BetaRs) bind to TGF-Beta within the alphavBeta8/L-TGF-Beta/GARP complex? To answer these questions, we will use cryo-EM to determine the structure of the alphavBeta8/L-TGF-Beta/GARP complex to determine how flexibility of L-TGF-Beta contributes to TGF-Beta activation, and finally we will capture the multimeric complex of TGF-BetaRs with alphavBeta8/LTGF-Beta/GARP. These studies will improve mechanistic understanding of TGF-Beta activation and therapeutic targeting strategies to inhibit it.

摘要/摘要：TGF-β 驱动导致肺和气道纤维化的纤维炎症过程。 该项目的长期目标是深入了解 TGF-Beta 活性的调节，以开发 治疗慢性纤维化肺病的新策略和治疗方法很少。 细胞因子 TGF-β 是肺部纤维化和炎症性疾病的主要介质。 病理性炎症，是纤维化肺病的潜在治疗靶点。 靶向 TGF-β 本身或其受体的效用受到啮齿类动物、灵长类动物和 人类非常需要针对 TGF-β 的纤维炎症作用的更具体的方法。 更具体地针对 TGF-β 的局部有希望作用的方法是针对其“激活”，因为它总是 以潜在形式（L-TGF-Beta）产生，必须被激活才能发挥作用。 能够促进更具体的靶向的是它通过 GARP 共价结合到特定的细胞表面。 与整合素 alphavBeta8 的结合对于体内 TGF-Beta 激活至关重要。对于 alphavBeta8 激活机制，如 与所有其他物质一样，长期以来人们一直认为 TGF-Beta 必须从 LAP 中释放出来，这样游离的 TGF-Beta 才能 根据最近使用单颗粒获得的结构数据，将其受体扩散并结合在靶细胞上。 电子冷冻显微镜（cryo-EM），我们最近提出了一种新模型，其中 alphavBeta8 可以与呈递 L-TGF-Beta/GARP 复合物的细胞上的 L-TGF-Beta 结合，并诱导信号传导，而无需释放和扩散 TGF-Beta。在这里，我们通过三个目标解决有关这种新 L-TGF-Beta 模型的三个关键问题。 (1) alphavBeta8/L-TGF-Beta/GARP三元复合物屏蔽TGF-Beta的L-TGF-Beta的哪些柔性结构域 (2) L-TGF-Beta 的灵活性是否需要通过与 alphavBeta8 结合来介导 TGF-Beta (3) TGF-Beta 受体 (TGF-BetaR) 是否与 alphavBeta8/L-TGF-Beta/GARP 复合物中的 TGF-Beta 结合？ 回答这些问题，我们将使用冷冻电镜来确定 alphavBeta8/L-TGF-Beta/GARP 复合物的结构 以确定 L-TGF-Beta 的灵活性如何促进 TGF-Beta 激活，最后我们将捕获 TGF-BetaR 与 alphavBeta8/LTGF-Beta/GARP 的多聚复合物这些研究将改善机制。 了解 TGF-β 激活和抑制它的治疗靶向策略。