Targeting the ADAM10-sEphrin-B2 pathway in pulmonary fibrosis

项目摘要/摘要 肺纤维化是一种致命的肺部疾病，其特征是肺部进行性破坏和疤痕形成。 最常见的形式是特发性肺纤维化(IPF)，患者患有不可逆转的和 以肺功能进行性下降为特征的最终致命的间质性肺病 阻碍呼吸的能力。瘢痕形成细胞肌成纤维细胞的激活是驱动力 进行性肺瘢痕形成、细胞外基质过度沉积和组织重塑的背后 与肺纤维化有关。相应地，分子介体的鉴定指导 肌成纤维细胞的激活，不仅将进一步提高我们对肺纤维化发病机制的认识， 也为新的抗纤维化治疗方法提供了合理的治疗靶点。我们最近确定了 ADAM10-sEPhin-B2通路是IPF患者和小鼠肌成纤维细胞激活的主要驱动因素 肺纤维化模型。我们最近的研究表明，肺损伤后，FULL-1的胞外区域- 静止期肺成纤维细胞中长度为eparin-B2的蛋白被去整合素和金属蛋白酶切割 ADAM10，导致生物活性分子可溶性EPhin-B2(sEPhin-B2)的产生。一次 通过激活EphB4受体，sEPhin-B2向静止的成纤维细胞发出促纤维化信号 以自分泌/旁分泌的方式发出信号。我们的研究表明，sEphin-B2/EphB4受体信号转导 促进静止的成纤维细胞分化为激活的肌成纤维细胞，并足以驱动组织 小鼠体内的纤维化。此外，在肺成纤维细胞中，遗传上缺乏eaffin-B2的小鼠表现出 显著预防博莱霉素性肺纤维化。因此，我们假设战略是为了 通过靶向ADAM10或直接阻断sEPhin-B2来中断sEPhin-B2的阐述，具有 有可能成为肺纤维化的新治疗策略。本申请中建议的研究包括 旨在确定ADAM10-sEPhin-B2途径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患者的这一途径。具体来说，我们建议 四个具体目标：(1)确定ADAM10在体内产生sEPhin-B2的细胞机制 并参与肺纤维化的发生发展；(2)探讨sEPhin-B2的作用机制 体外诱导肌成纤维细胞活化；(3)测定抗sE-B2的治疗效果 临床前和人类IPF模型中的中和抗体，以及(4)评估血浆sEPhin-B2水平 一种新的预测IPF预后的生物标志物。这项申请中提出的实验将描绘出新的 ADAM10-sEPhin-B2途径促进肺纤维化的机制。我们还将确定 阻断这一通路是否有可能成为一种有效的新的治疗策略 IPF，一种不治之症和致命疾病。

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.