Role of ER Stress in the Pathogenesis of Primary Open Angle Glaucoma

摘要 原发性开角型青光眼（POAG）是最常见的青光眼形式，通常伴有 由于小梁网（TM）无法维持正常水平的眼压（IOP）升高， 房水流出我们最近建立了一种新的转基因小鼠模型（Tg-MYOCY 437 H）， 表达突变型肌球蛋白，一种已知的人类POAG的主要遗传原因， 青光眼表型重要的是，我们已经将内质网（ER）应激与 在Tg-MYOCY 437 H小鼠中的青光眼发病机制。错误折叠的myocilin在ER中积累，诱导ER 应激并激活保护性未折叠蛋白反应（UPR）。沿着UPR的激活， 还诱导自噬，这是一种已知降解蛋白质聚集体的溶酶体降解过程。然而，在这方面， 可能由于UPR不足和自噬受损而无法消除肌球蛋白聚集体，TM细胞 诱导ER应激启动的凋亡转录因子Chop，这可能进一步恶化ER稳态 并引起TM功能障碍/丧失，升高IOP并导致POAG。目前的建议将进一步 探讨慢性内质网应激在肌钙蛋白以及非肌钙蛋白相关的 POAG。在辅导阶段，拟议的研究将确定是否未能启动 保护性UPR（Atf-6 <$-/-）加重青光眼表型，而干扰ER应激诱导的 细胞凋亡（Chop-/-）预防Tg-MYOCY 437 H小鼠的青光眼。此外，我们还将调查ER是否 应激在POAG供体的port-mortem TM组织中被激活。在独立阶段，我们将 检查TM中ER应激的诱导是否与小鼠模型中IOP的升高相关。 地塞米松诱导的高眼压此外，我们将研究自噬在降解中的作用， 并将决定雷帕霉素诱导自噬是否能挽救青光眼 Tg-MYOCY 437 H小鼠的免疫反应。具体来说，候选人将学习和生成ER压力的新模型， Atf 6和Chop基因敲除小鼠，产生诱导多能干细胞（iPSC）衍生的小梁网， 从POAG患者的细胞，并表征地塞米松诱导的高眼压小鼠模型 在瓦尔谢菲尔德博士的实验室里此外，在辅导阶段，候选人将继续他的 通过咨询委员会的持续指导，促进专业和科学职业发展。他 我将参加科学会议，并与急诊室压力专家，托马斯Rutkowski博士和青光眼合作 临床专家李·阿尔沃德医生他还将获得教学经验。该项目将继续促进 对候选人进行技术、智力和专业培训，并协助候选人建立 一个学术研究机构的独立研究实验室。

Abstract Primary open angle glaucoma (POAG), the most common form of glaucoma, is usually accompanied by elevated intraocular pressure (IOP) due to failure of the trabecular meshwork (TM) to maintain normal levels of aqueous humor outflow. We recently generated a novel transgenic murine model (Tg-MYOCY437H) that expresses mutant myocilin, a known leading genetic cause of POAG in humans and replicates human glaucoma phenotypes. Importantly, we have associated endoplasmic reticulum (ER) stress to the pathogenesis of glaucoma in Tg-MYOCY437H mice. Misfolded myocilin accumulates in the ER, induces ER stress and activates a protective unfolded protein response (UPR). Along with UPR activation, mutant myocilin also induces autophagy, a process of lysosomal degradation known to degrade protein aggregates. However, failure to eliminate myocilin aggregates possibly due to insufficient UPR and impaired autophagy, TM cells induce the ER stress-initiated apoptotic transcriptional factor, Chop, which may further worsen ER homeostasis and cause TM dysfunction/loss, elevating IOP and resulting in POAG. The current proposal will further investigate the role of chronic ER stress in the pathogenesis of myocilin as well as non-myocilin associated POAG. During the mentored phase, the proposed studies will determine whether failure to activate the protective UPR (Atf-6¿-/-) exacerbates glaucoma phenotypes, whereas interference with ER stress-induced apoptosis (Chop-/-) prevents glaucoma in Tg-MYOCY437H mice. In addition, we will investigate whether ER stress is activated in port-mortem TM tissues from POAG donors. During the independent phase, we will examine whether induction of ER stress in the TM is associated with elevation of IOP in a mouse model of dexamethasone-induced ocular hypertension. In addition, we will examine the role of autophagy in degradation of myocilin aggregates and will determine whether inducing autophagy by rapamycin will rescue the glaucoma of Tg-MYOCY437H mice. Specifically, the candidate will learn and generate new models of ER stress using Atf6¿ and Chop knockout mice, generate induced pluripotent stem cells (iPSCs)-derived trabecular meshwork- like cells from POAG patients, and characterize a dexamethasone-induced ocular hypertension mouse model in the laboratory of Dr. Val Sheffield. Additionally, during the mentored phase, the candidate will continue his professional and scientific career development through continual guidance from the advisory committee. He will attend scientific conferences, and collaborate with ER stress expert, Dr. Thomas Rutkowski and glaucoma clinical expert, Dr. Lee Alward. He will also acquire teaching experience. This project will facilitate continued technical, intellectual, and professional training of the candidate, and assist the candidate in the establishment of an independent research laboratory at an academic research institute.