Mechanisms of lens epithelium fibrosis and its relevance to posterior capsule opacification

摘要 白内障手术与后囊混浊(PCO)的高风险相关，PCO是继发性白内障的一种形式 白内障，其形成机制仍鲜为人知。然而，PCO通常被认为是一种慢性 疾病和LEC纤维化过程的后果，部分归因于上皮-间充质转化 其中转化生长因子β介导的信号转导是其中的关键环节之一。最近，我们和其他人建议 规范的Wnt/β-catenin信号转导通路在晶状体上皮细胞纤维化和后发性白内障的发病机制中也起着关键作用。至 在慢性条件下测试Wnt信号，我们进行了为期6个月的动态兔白内障手术研究和 在PCO形成过程中发现了典型的Wnt信号的深刻激活，与 氧化升高和慢性炎症。我们假设晶状体上皮细胞(LECs)经历自我 调节信号转导以适应白内障术后新的微环境，并规范 Wnt/β-catenin在这一过程中起着关键作用。我们的初步研究发现WNT3是一种高度表达的 白内障术后人和小鼠晶状体上皮细胞Wnt家族基因上调然而，WNT3的作用 信号介导的LEC纤维化和后囊混浊的形成仍不清楚；晶状体如何形成的潜在机制 上皮细胞对Wnt信号的调控仍有待解决。我们计划用一个基础来解开这些谜题 得到了我们试点研究的几个关键发现的支持，例如，我们发现LEC将WNT3打包成 Exosome是细胞外小泡的一种，以内分泌的方式进行信号转导。 重要的是，炎性细胞因子，如肿瘤坏死因子α，可以极大地促进外切体的生物发生和WNT3 分泌物。目的1将测试晶状体上皮细胞如何调节WNT3包装和外切体的生物发生。我们需要 为了了解LECs如何在一定的刺激下促进外切体的生物发生和WNT3的分泌， 例如，炎性细胞因子和氧化应激。目标2将描述WNT3在LEC增殖中的作用， 利用体外细胞培养、原代细胞培养、体外外植体培养和体内培养进行迁移和分化 老鼠模型。AIM3研究晶状体上皮细胞的生长微环境和WNT3介导的自分泌信号转导 使用有和没有白内障手术史的人体组织。人体组织研究将提供最终的 细胞培养和动物模型研究后的研究检查点。总而言之，大量试点数据表格 我们的建议的基础，将揭开一条新的LECs自我调节途径，这让人想起 白内障手术的病理和生理条件。

Abstract Cataract surgery is associated with a high risk of posterior capsule opacification (PCO), a form of secondary cataract, the formation of which is still poorly understood. However, PCO is generally considered a chronic disease and a consequence of the LEC fibrotic process, attributed in part to the epithelial-mesenchymal transition (EMT) in which TGFβ mediated signaling is one of the key players. Recently, we and others have suggested that canonical Wnt/β-catenin signaling is also a pivotal player in LEC fibrosis and the pathogenesis of PCO. To test the Wnt signaling in chronic conditions, we conducted a 6-month-kinetic rabbit cataract surgery study and found a profound activation of the canonical Wnt signaling during the course of PCO formation, associated with elevated oxidation and chronic inflammation. We postulate that lens epithelial cells (LECs) undergo self- regulatory signaling transduction to adapt to the new microenvironment after cataract surgery, and the canonical Wnt/β-catenin plays a pivotal role in this process. Our initial study identifies Wnt3 as a highly expressed and upregulated Wnt-family gene in human and mouse LECs after cataract surgery. However, the role of Wnt3 signaling mediated LEC fibrosis and PCO formation is still unclear; the underlying mechanisms of how lens epithelial cells regulate the Wnt signaling remain to be addressed. We plan to unravel these puzzles with a basis of support from several key findings of our pilot studies, e.g., our discovery that LECs package Wnt3 into exosomes, a type of extracellular vesicle (EVs), and conduct signaling transduction in an endocrine fashion. Importantly, inflammatory cytokines, such as TNFα, can drastically promote exosome biogenesis and Wnt3 secretion. Aim 1 will test how lens epithelial cells regulate Wnt3 packaging and exosome biogenesis. We need to understand how LECs manage to promote exosome biogenesis and Wnt3 secretion under the certain stimuli, e.g., inflammatory cytokines and oxidative stress. Aim 2 will delineate the role of Wnt3 in LEC proliferation, migration, and differentiation using in vitro cell culture, primary cell culture, ex vivo explant culture, and in vivo mouse models. Aim3 studies the LECs’ growth microenvironment and the Wnt3 mediated autocrine signaling by using human tissue with and without a history of cataract surgery. Human tissue studies will offer a final checkpoint of research after studies from cell culture and animal models. In summary, substantial pilot data form the basis of our proposal, one which will unravel a novel LECs self-regulatory pathway that is closely reminiscent of the pathological and physiological conditions of cataract surgery.