Molecular Mechanisms of Diabetic Retinal Ganglion Cell Dysfunction and Neurovascular Crosstalk in Early Diabetic Retinopathy

项目摘要/摘要 糖尿病视网膜病变(DR)是导致工作年龄成年人失明的主要原因，并导致视力丧失。 到增殖性视网膜新生血管和糖尿病黄斑水肿的后遗症。因此，它已经 传统上被认为是视网膜微血管疾病。然而，糖尿病也与 伴有视网膜神经元损害和糖尿病患者在发病前就表现出视觉功能障碍 临床--明显的视网膜病变。来自糖尿病患者和小鼠模型的越来越多的证据进一步 表现为进行性视网膜内神经元丢失，这在疾病的早期就存在， 先于临床确认的视网膜血管改变。早期糖尿病视网膜发病的分子机制 神经退行性变尚不清楚，尽管线粒体功能障碍已被认为与DR有关，主要是在 全视网膜和血管内皮细胞的研究。线粒体功能障碍也被证明是起作用的 罕见遗传性帕金森氏病(PD)神经变性发病机制中的关键作用 与吞丝分裂基因PINK1和PARKIN突变相关的帕金森病。泰德博士的实验室 道森，首席研究员的主要导师，已经确定了一种新的与parkin相互作用的底物，paris， 它通过抑制PGC1a来调节线粒体的生物发生，并证明了 帕金森病背景下的多巴胺能神经元主要是由线粒体损伤驱动的 通过Parkin/Paris/PGC1a途径的生物发生。线粒体生物发生的作用及其与生物发生的平衡 糖尿病条件下视网膜神经节细胞(RGC)的丝裂原吞噬作用尚未被探索。假说 这项研究的主要结论是：(1)糖尿病直接导致RGC功能障碍和RGC受损。 线粒体质量调节的Parkin/Paris/PGC1a通路以及(2)RGCs功能障碍 设定直接影响视网膜血管系统的分泌因子。在唐博士的额外指导下 Zack和Gerard Lutty博士，在约翰·霍普金斯大学丰富的合作环境中 这些假说将在原代培养小鼠的体外实验中得到验证 RGCs和hESC来源的RGCs，以及体内糖尿病小鼠模型(链脲佐菌素)。校长 研究人员是一名医学/博士临床医生兼科学家，她完成了玻璃体视网膜外科医生的培训，现在 定期护理因糖尿病视网膜疾病而致视力丧失的患者，尽管目前有 治疗，激励她研究疾病发病机制的新分子途径。她目前 第一年获得约翰霍普金斯大学眼科K12助学金。建立在 作为她博士研究的基础，这项K08奖将促进她需要的额外专业知识和培训 解决了她的假设，并最终过渡到视网膜独立研究员的职位 神经元代谢、视网膜神经保护和神经血管串扰。

PROJECT SUMMARY/ABSTRACT Diabetic retinopathy (DR) represents the leading cause of blindness in working-age adults, with vision loss due to sequelae of proliferative retinal neovascularization and diabetic macular edema (DME). As such, it has traditionally been considered a disease of the retinal microvasculature. However, diabetes is also associated with retinal neuronal damage and diabetic patients exhibit visual functional deficits prior to the onset of clinically-apparent retinopathy. Increasing evidence from both diabetic patients and mouse models has further demonstrated progressive inner retinal neuronal loss which is present early in the course of the disease, preceding clinically-identified retinal vascular changes. The molecular mechanisms of early diabetic retinal neurodegeneration are unknown, although mitochondrial dysfunction has been implicated in DR, primarily in studies of whole retina and vascular endothelial cells. Mitochondrial dysfunction has also been shown to play a critical role in the pathogenesis of neurodegeneration in Parkinson’s disease (PD), with rare hereditary forms of PD associated with mutations in the mitophagy genes PINK1 and parkin. The laboratory of Dr. Ted Dawson, the principal investigator’s primary mentor, has identified a novel parkin-interacting substrate, PARIS, which regulates mitochondrial biogenesis via repression of PGC1a and has demonstrated that loss of dopaminergic neurons in the setting of parkin deficiency is driven primarily by impairments in mitochondrial biogenesis via the parkin/PARIS/PGC1a pathway. The role of mitochondrial biogenesis and its balance with mitophagy in retinal ganglion cells (RGCs) under diabetic conditions has not been explored. The hypotheses of this project are that (1) diabetes directly induces RGC dysfunction and loss via perturbations in the parkin/PARIS/PGC1a pathway of mitochondrial mass regulation, and that (2) dysfunctional RGCs in this setting secrete factors that directly affect the retinal vasculature. Under the additional mentorship of Dr. Don Zack and Dr. Gerard Lutty, and within the rich collaborative environment of the Johns Hopkins University School of Medicine, these hypotheses will be tested using in vitro approaches with primary cultured murine RGCs and hESC-derived RGCs, and in an in vivo mouse model of diabetes (streptozocin). The principal investigator is an MD/PhD clinician-scientist, who completed her training as a Vitreoretinal Surgeon, and now regularly cares for patients with vision loss due to diabetic retinal disease despite currently-available treatments, motivating her to investigate novel molecular pathways of disease pathogenesis. She is currently in year one of support from the Johns Hopkins Department of Ophthalmology K12 grant. Building upon the foundation of her PhD research, this K08 award will facilitate the additional expertise and training she needs to address her hypotheses and eventually transition to a position as an independent investigator in retinal neuronal metabolism, retinal neuroprotection, and neurovascular crosstalk.