TGFB signaling as a therapeutic target in cataract and PCO

描述(申请人提供)：国家眼科研究所晶状体与白内障项目的一个核心目标是白内障的预防和治疗。眼生长因子TGF2参与了前囊下白内障(ASC)和后囊混浊(PCO)的发生发展，在这种视力损害的情况下，晶状体细胞的纤维分化和上皮向间充质转化(EMT)都发生了病理上的上调。尽管TGF2在体外和体内诱导晶状体上皮细胞发生EMT已被证实，但它在与PCO和ASC相关的纤维样改变中的作用尚不清楚。我们开发了一个创新的模型系统来研究生长因子介导的晶状体信号转导，分离的细胞来源的原代胚胎鸡晶状体细胞(DCDMLs)的单层培养。在这一应用中，我们发现DCDMLs是第一个可以研究TGF2诱导EMT和纤维分化能力的培养系统，这为确定这两种细胞命运的分子机制提供了前所未有的机会，并为发现潜在的抗PCO/ASC药物提供了一个新的系统。小分子酪氨酸激酶抑制剂作为靶向治疗药物的使用使某些癌症的治疗发生了革命性的变化。我们发现，在临床使用的浓度下，即使在单一的1小时治疗后，一种这样的抑制剂也可以阻止DCDML中TGF2下游的EMT和纤维样变化。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以用于对抗引起ASC和PCO的晶状体细胞的两种病理命运的可能性。拟议研究的目的是了解该化合物作用的机制基础，通过一种新的小分子激酶抑制剂筛选发现其他潜在的抗PCO/ASC治疗药物，并在已建立的人晶状体细胞纤维化的体外模型中测试这些化合物。这项工作将阐明TGF2促进晶状体细胞EMT和纤维分化的信号转导途径，并为预防PCO和ASC开辟新的途径。此外，它还可能为已经或正在获得FDA批准用于人类使用的药物提供新的申请。 与公共健康相关：据估计，美国每年有300万例白内障手术，随着人口老龄化，这一比例预计将急剧上升。我们研究的目标是在预防白内障和白内障手术中最常见的并发症--后囊混浊的新疗法中针对TGF2介导的信号转导级联反应。我们已经发现了在培养的晶状体细胞中阻断TGF2有害影响的药物，并希望了解它们的作用机制以及这些药物如何用于保护人类的视力。

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.