TGFB signaling as a therapeutic target in cataract and PCO

描述（由申请人提供）：国家眼科研究所透镜和白内障项目的核心目标是预防和治疗白内障。眼生长因子TGF 2参与前囊下白内障（ASC）和后囊膜混浊（PCO）的发展，这是一种视力损害状况，其中透镜细胞的纤维分化和上皮细胞向间充质细胞转化（EMT）均病理性上调。尽管TGF-2在体内和体外诱导透镜细胞EMT已被证实，但其在与PCO和ASC相关的纤维样变化中的作用尚不清楚。我们已经开发了一种创新的模型系统来研究生长因子介导的信号转导在透镜中，原代鸡胚透镜细胞（DCDMLs）的解离细胞衍生的单层培养物。在本申请中，我们表明DCDMLs是第一个培养系统，其中TGF 2诱导EMT以及纤维分化的能力可以进行研究，提供了一个前所未有的机会，以确定管理这两个细胞命运的分子机制和一个新的系统，以发现潜在的抗PCO/ASC药物。小分子酪氨酸激酶抑制剂作为靶向治疗剂的使用已经彻底改变了某些癌症的治疗。我们已经发现，在临床使用的浓度下，一种这样的抑制剂阻断DCDMLs中TGF 2下游的EMT样和纤维样变化，即使在单次1小时治疗后也是如此。这些发现首次提出了一种耐受性良好的小分子激酶抑制剂可用于对抗引起ASC和PCO的透镜细胞的两种病理结局的可能性。拟定研究的目的是了解该化合物作用的机制基础，使用新型小分子激酶抑制剂筛选发现其他潜在的抗PCO/ASC治疗剂，并在已建立的人透镜细胞纤维化离体模型中测试这些化合物。本研究将阐明TGF-2促进透镜细胞EMT和纤维分化的信号转导途径，为PCO和ASC的防治开辟新途径。此外，它还可能为已经或正在获得FDA批准用于人类的药物提供新的应用。 公共卫生相关性：据估计，美国每年进行300万例白内障手术，随着人口老龄化，这一比率预计将急剧上升。我们研究的目标是在新的治疗方法中靶向TGF 2介导的信号转导级联，以预防白内障和白内障手术最常见的并发症，后囊膜混浊。我们已经发现了阻断TGF-2在培养的透镜细胞中的有害作用的药物，并希望了解它们的作用机制以及如何使用这些药物来保护人类的视力。

DESCRIPTION (provided by applicant): A core goal of the Lens and Cataract Program of the National Eye Institute is the prevention and treatment of cataract. The ocular growth factor TGF2 is involved in the development of anterior subcapsular cataracts (ASC) and of posterior capsule opacification (PCO), vision-impairing conditions in which both fiber differentiation and epithelial-to- mesenchymal transition (EMT) of lens cells are pathologically upregulated. Although it is well established that TGF2 induces EMT in lens cells in vitro and in vivo, its role in the fiber-like changes associated with PCO and ASC are unknown. We have developed an innovative model system to study growth factor-mediated signal transduction in the lens, dissociated cell- derived monolayer cultures of primary embryonic chick lens cells (DCDMLs). In this application, we show that DCDMLs are the first culture system in which the ability of TGF2 to induce EMT as well as fiber differentiation can be studied, providing an unprecedented opportunity to identify the molecular mechanisms that govern these two cell fates and a novel system to discover potential anti-PCO/ASC drugs. The use of small molecule tyrosine kinase inhibitors as targeted therapeutics has revolutionized the treatment of certain cancers. We have discovered that at clinically used concentrations, one such inhibitor blocks both the EMT- and fiber-like changes downstream of TGF2 in DCDMLs, even after a single, 1 hour treatment. These findings raise, for the first time, the possibility that a well-tolerated small molecule kinase inhibitor could be used to combat both of the pathological fates of lens cells that cause ASC and PCO. The aims of the proposed studies are to understand the mechanistic basis of the effects of this compound, discover other potential anti-PCO/ASC therapeutics using a novel small molecule kinase inhibitor screen, and test these compounds in established ex vivo models of human lens cell fibrosis. This work will elucidate the signal transduction pathways by which TGF2 enhances EMT and fiber differentiation in lens cells, and open up a novel approach for the prevention of PCO and ASC. Moreover, it will potentially provide new applications for drugs that have, or are in the process of acquiring, FDA approval for human use. PUBLIC HEALTH RELEVANCE: An estimated 3 million cataract surgeries are conducted in the US annually, a rate projected to rise sharply as the population ages. The goal of our research is to target TGF2-mediated signal transduction cascades in new therapies to prevent cataract and the most common complication of cataract surgery, posterior capsule opacification. We have discovered drugs that block the deleterious effects of TGF2 in cultured lens cells, and want to understand the mechanisms of their effects and how these drugs can be used to preserve vision in humans.