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

内质网应激在原发性开角型青光眼发病机制中的作用

• 批准号: 8383990
• 负责人: Gulab Zode
• 金额: $ 8.77万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8383990
• 关键词: Advisory Committees; Apoptosis; Apoptotic; Aqueous Humor; Autophagocytosis; Autopsy; Cell Death; Cells; Chronic; Clinical; Data; Degradation Pathway; Development; Dexamethasone; Diagnosis; Disease; Educational process of instructing; Endoplasmic Reticulum; Eye; Failure; Functional disorder; GRP78 gene; GRP94; Genetic; Glaucoma; Homeostasis; Human; Individual; Knockout Mice; Laboratories; Laboratory Research; Lead; Learning; Lysosomes; Mentors; Modeling; Molecular Chaperones; Mus; Mutation; Nerve Degeneration; Ocular Hypertension; Optic Nerve; Pathogenesis; Pathway interactions; Patients; Phase; Phenotype; Phenylbutyrates; Phosphorylation; Physiologic Intraocular Pressure; Play; Primary Open Angle Glaucoma; Process; Proteins; Research Institute; Resistance; Retinal Ganglion Cells; Risk Factors; Role; Sirolimus; Sodium phenylbutyrate; Steroids; Testing; Tissues; Topical application; Trabecular meshwork structure; Training; Transgenic Mice; Transgenic Organisms; Western Blotting; career development; common treatment; endoplasmic reticulum stress; experience; genetic risk assessment; improved; induced pluripotent stem cell; inhibitor/antagonist; insight; mouse model; mutant; myocilin; novel; prevent; protein aggregate; protein degradation; protein misfolding; response; sensor; symposium

DESCRIPTION (provided by applicant): 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, intellectul, and professional training of the candidate, and assist the candidate in the establishment of an independent research laboratory at an academic research institute. PUBLIC HEALTH RELEVANCE: The successful completion of this project will lead to insight into elevated intraocular pressure, a major risk factor of the human blinding disorder, primary open angle glaucoma. The results will potentially improve diagnosis, genetic risk assessment and treatment of this common disorder.

描述(申请人提供)：原发性开角型青光眼(POAG)是最常见的青光眼形式，由于小梁网(TM)未能维持正常的房水流出水平，通常伴随高眼压(IOP)。我们最近建立了一种新的转基因小鼠模型(TG-MYOCY437H)，该模型表达突变的myoclin，这是已知的人类POAG的主要遗传原因，并复制了人类青光眼的表型。重要的是，我们发现内质网应激与TG-MYOCY437H小鼠青光眼的发病机制有关。错误折叠的肌球蛋白在内质网中积聚，诱导内质网应激，并激活保护性未折叠蛋白反应(UPR)。在UPR激活的同时，突变的myocin还诱导自噬，这是一个已知的降解蛋白质聚集体的溶酶体降解过程。然而，由于UPR不足和自噬功能受损，TM细胞不能清除myocin聚集体，从而诱导内质网应激启动的凋亡转录因子CHOP，这可能进一步恶化内质网稳态，导致TM功能障碍/丢失，升高眼压，导致POAG。目前的建议将进一步研究慢性内质网应激在霉菌素相关的POAG和非霉菌素相关性POAG的发病机制中的作用。在指导阶段，拟议的研究将确定未能激活保护性UPR(ATF-6-/-)是否会加剧青光眼表型，而干扰内质网应激诱导的细胞凋亡(CHOP-/-)则可以预防TG-MYOCY437H小鼠的青光眼。此外，我们还将调查POAG供者的临死TM组织中是否存在内质网应激。在独立阶段，我们将检验在地塞米松诱导的高眼压小鼠模型中，TM内质网应激的诱导是否与眼压升高有关。此外，我们将研究自噬在霉菌素聚集体降解中的作用，并将确定用雷帕霉素诱导自噬是否可以挽救TG-MYOCY437H小鼠的青光眼。具体地说，候选人将利用ATF6和CHOP基因敲除小鼠学习并产生新的ER应激模型，从POAG患者中产生诱导多能干细胞(IPSCs)来源的小梁网状细胞，并在Val Shefffield博士的实验室中鉴定地塞米松诱导的高眼压小鼠模型。此外，在指导阶段，候选人将通过咨询委员会的持续指导继续其专业和科学的职业发展。他将出席科学会议，并与ER压力专家Thomas Rutkowski博士和青光眼临床专家Lee Alward博士合作。他还将获得教学经验。该项目将促进候选人继续接受技术、知识和专业培训，并协助候选人在学术研究机构建立独立的研究实验室。 公共卫生相关性：该项目的成功完成将有助于深入了解眼压升高，这是人类致盲障碍--原发性开角型青光眼的主要风险因素。这一结果可能会改善这种常见疾病的诊断、遗传风险评估和治疗。