Targeting the ADAM10-sEphrin-B2 pathway in pulmonary fibrosis

项目总结/摘要 肺纤维化是一种致命的肺部疾病，其特征在于肺部的进行性破坏和瘢痕形成。 患有最常见形式特发性肺纤维化（IPF）的患者患有不可逆的和严重的肺纤维化。 最终致死性间质性肺病，其特征为肺功能进行性下降，最终 阻碍呼吸的能力。激活的疤痕形成细胞命名肌成纤维细胞是驱动力 在进行性肺瘢痕形成、过度细胞外基质（ECM）沉积和组织重塑的背后， 与肺纤维化有关。因此，分子介导物的鉴定 肌成纤维细胞活化，不仅将进一步增强我们对肺纤维化发病机制的理解， 也为新型抗纤维化治疗提供了合理的治疗靶点。我们最近发现， ADAM 10-sEphrin-B2通路作为IPF患者和小鼠中肌成纤维细胞活化的主要驱动因素 肺纤维化模型。我们最近的研究表明，肺损伤后，全- 静止肺成纤维细胞中的长度肝配蛋白-B2被去整合素和金属蛋白酶蛋白水解切割 ADAM 10，导致生物活性分子可溶性Ephrin-B2（sEphrin-B2）的产生。一旦 脱落，sEphrin-B2通过激活EphB 4受体向静止成纤维细胞产生促纤维化信号传导 以自分泌/旁分泌方式进行信号传导。我们的研究表明sEphrin-B2/EphB 4受体信号转导 促进静止的成纤维细胞分化为活化的肌成纤维细胞， 在小鼠体内的纤维化。此外，在肺成纤维细胞中特异性遗传缺乏肝配蛋白-B2的小鼠表现出 对博来霉素诱导的肺纤维化具有显著的保护作用。因此，我们假设， 通过靶向ADAM 10或直接阻断sEphrin-B2， 有可能作为肺纤维化的新治疗策略。本申请中提出的研究是 旨在定义ADAM 10-sEphrin-B2通路驱动肺纤维化的生物学机制 并开发新的治疗策略来抑制IPF患者的这一通路。具体来说，我们建议 具体目的有四个：（1）确定ADAM 10在体内产生sEphrin-B2的细胞机制 （2）探讨sEphrin-B2在肺纤维化中的作用机制 （3）确定抗sEphrin-B2抗体的治疗效果 临床前和人IPF模型中的中和抗体，和（4）评价血浆sEphrin-B2水平， 一种新的IPF预后生物标志物。本申请中提出的实验将描绘新颖的 ADAM 10-sEphrin-B2途径促进肺纤维化的机制。我们还将确定 该途径的治疗性阻断是否有可能成为一种有效的新治疗策略， IPF是一种无法治愈的致命疾病。

Project Summary/Abstract Pulmonary fibrosis is a fatal lung disease characterized by progressive destruction and scarring of the lungs. Patients with the most common form, Idiopathic Pulmonary Fibrosis (IPF), suffer from irreversible and ultimately fatal interstitial lung disease characterized by progressive decline in lung function, ultimately impeding the ability to breathe. Activation of scar-forming cells named myofibroblasts is the driving force behind progressive lung scarring, excessive extracellular matrix (ECM) deposition and tissue remodeling associated with pulmonary fibrosis. Accordingly, the identification of the molecular mediators directing myofibroblast activation, will not only further enhance our understanding of the pathogenesis of lung fibrosis, but also provide rational therapeutic targets for novel anti-fibrotic therapies. We have recently identified the ADAM10-sEphrin-B2 pathway as a major driver of myofibroblast activation in patients with IPF and in mouse models of lung fibrosis. Our recent studies have demonstrated that following lung injury the ectodomain of full- length ephrin-B2 in quiescent lung fibroblasts is proteolytically cleaved by the disintegrin and metalloproteinase ADAM10, resulting in the generation of the biologically active molecule soluble Ephrin-B2 (sEphrin-B2). Once shed, sEphrin-B2 generates pro-fibrotic signaling to quiescent fibroblasts by activating EphB4 receptor signaling in an autocrine/paracrine manner. Our studies demonstrate that sEphrin-B2/EphB4 receptor signaling promotes differentiation of quiescent fibroblasts into activated myofibroblasts and is sufficient to drive tissue fibrosis in mice in vivo. Further, mice genetically lacking ephrin-B2 specifically in lung fibroblasts exhibit significant protection from bleomycin-induced lung fibrosis. Consequently, we hypothesize that strategies to interrupt the elaboration of sEphrin-B2, by targeting ADAM10, or blocking sEphrin-B2 directly, have the potential to serve as novel therapeutic strategies for lung fibrosis. The studies proposed in this application are designed to define the biological mechanisms by which the ADAM10-sEphrin-B2 pathway drives lung fibrosis and to develop novel therapeutic strategies to inhibit this pathway in patients with IPF. Specifically, we propose four specific aims: (1) To determine the cellular mechanisms by which ADAM10 generates sEphrin-B2 in vivo and contributes to the development of lung fibrosis, (2) To investigate the mechanisms by which sEphrin-B2 induces myofibroblast activation in vitro, (3) To determine the therapeutic efficacy of anti-sEphrin-B2 neutralizing antibodies in preclinical and human IPF models, and (4) To evaluate plasma sEphrin-B2 levels as a novel prognostic biomarker in IPF. The experiments proposed in this application will delineate novel mechanisms whereby the ADAM10-sEphrin-B2 pathway promotes lung fibrosis. We will also determine whether therapeutic blockade of this pathway has the potential to be an effective new therapeutic strategy for IPF, an incurable and deadly disease.