RPE Cell Bystander Effects Contribute to AMD Pathology

RPE 细胞旁观者效应有助于 AMD 病理学

• 批准号: 9137278
• 负责人: Baerbel Rohrer
• 金额: --
• 依托单位: RALPH H JOHNSON VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9137278
• 关键词: Adult; Age; Age related macular degeneration; Aging; American; Apical; Area; Atrophic; Back; Blindness; Bruch' s basal membrane structure; Bystander Effect; Caring; Cell Aging; Cell Surface Receptors; Cells; Choroid; Chronic; Communication; Complement; Complement Activation; Complex; Data; Disease; Drusen; Event; Eye; Feeds; Gap Junctions; Generations; Genetic; Homeostasis; Incidence; Individual; Inflammation; Ligands; Lipids; Location; Mediating; Metabolic; Metabolic stress; Metalcaptase; Mitochondria; Normalcy; Oxidation-Reduction; Oxidative Stress; Pathology; Pathway interactions; Patients; Photoreceptors; Population; Predisposition; Prevalence; Process; Recording of previous events; Research; Rest; Retina; Retinal; Risk; Risk Factors; Scheme; Severities; Shapes; Signal Transduction; Site; Smoking; Source; Stress; Structure of retinal pigment epithelium; Supporting Cell; System; Therapeutic; Tissues; Veterans; Xanthine Oxidase; base; biological adaptation to stress; cell age; cobra venom factor; design; exosome; fovea centralis; genetic risk factor; geographic atrophy; induced pluripotent stem cell; macula; metabolic profile; microvesicles; monolayer; neovascularization; oxidative damage; public health relevance; research study; response; therapeutic development; therapeutic target; tool; vector

 DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is a slowly progressing multifactorial disease involving genetic ab- normalities and environmental insults. AMD is the leading cause of blindness for Americans over age 60. As the population ages, the prevalence of AMD will reach a maximum risk rate of ~30% at age 75. As smoking increases the risk of AMD and there is a 20% higher incidence of smoking in veterans than in the general US civilian population, the VA system will have to provide care for potentially ≥7 million AMD cases. The current concepts of AMD recognize that chronic oxidative stress and inflammation (including complement activation) can trigger pathological changes in RPE, Bruch's membrane (BrM) and choroid. However, what this scheme does not consider is the "regionality" of AMD. Damage does not start in one location to spread from there, but is triggered in many different locations. This suggests that damage occurs in susceptible areas, while delaying it in more resilient areas (sparing of the fovea). Our research is based on the premise that the RPE is a site of aging and disease. The RPE is an essential support cell of the retina; it is a source for the debris found in drusen and BrM; and th RPE cells form a network of cells, connected via gap junctions (GJ). Hence the RPE is a prime candidate to either spread or limit the stress-response within the posterior pole. Spreading of infor- mation, or the bystander effect, can be mediated by two different mechanisms: transfer of a secreted signal to the recipient (individual molecules or signals contained in exosomes); or the spread of information by means of communication via GJ. Here we will be guided by our overall hypothesis that exosome and GJ-mediated com- munication in RPE monolayers contribute of the bystander effect and mediate regionality of RPE damage. The susceptibility of individual cells to the bystander effects is thought to be determined by their metabolic profile. Hence we further hypothesize that the resting state of the individual cell within a network will determine is sus- ceptibility to stress. [[These questions will be investigated in RPE networks derived from ARPE-19 cells as well as induced pluripotent stem cell-derived RPE cells from AMD and control patients with low and high genetic risk factors for AMD]]. In Aim 1, we will determine the effects of messengers contained in exosomes in execut- ing the bystander effect in RPE cells. We have demonstrated that exosomes generated by oxidative stress can serve as signaling vectors for communication between donor and recipient cells in a complement-dependent manner. This mechanism will be explored further to determine the polarity of exosome formation, the activity of exosomes on global and single cell responses, and the process by which exosomes transfer information. Aim 2 is designed to determine the effects of GJ communication in executing the bystander effect. Our preliminary data has shown that local oxidative stress in a donor cell can trigger spread of information leading to changes in mitochondrial homeostasis in a limited number of connected recipient cells. This observation will be further extended to determine the signaling events in donor and recipient cells elicited by local stress as well as the metabolic baseline parameters in recipient cells that correlate with susceptibility to responding to information from a donor cell, and to examine potential messengers that mediate GJ communication.

 描述（由申请人提供）： 年龄相关性黄斑变性（AMD）是一种缓慢进展的多因素疾病，涉及遗传异常和环境损害。 AMD 是导致 60 岁以上美国人失明的主要原因。随着人口老龄化，AMD 的患病率将在 75 岁时达到最大风险率约 30%。由于吸烟会增加 AMD 的风险，而且退伍军人的吸烟率比一般美国平民高 20%，因此 VA 系统将必须为潜在的 ≥ 700 万 AMD 病例提供护理。目前AMD的概念认识到慢性氧化应激和炎症（包括补体激活）可以引发RPE、布鲁赫膜（BrM）和脉络膜的病理变化。不过，这个方案没有考虑到的是AMD的“地域性”。伤害不会从一个位置开始并从那里扩散，而是在许多不同的位置触发。这表明损伤发生在易受影响的区域，而在更有弹性的区域则延迟了损伤（不影响中央凹）。我们的研究基于这样一个前提：RPE 是衰老和疾病的部位。 RPE 是视网膜的重要支持细胞；它是玻璃疣和 BrM 中发现的碎片的来源； RPE 细胞形成细胞网络，通过间隙连接 (GJ) 连接。因此，RPE 是分散或限制后极内压力反应的主要候选者。信息的传播或旁观者效应可以通过两种不同的机制介导：将分泌的信号转移到接受者（外泌体中包含的单个分子或信号）；或通过 GJ 进行通信来传播信息。在这里，我们将以我们的总体假设为指导，即 RPE 单层中外泌体和 GJ 介导的通讯有助于旁观者效应并介导 RPE 损伤的区域性。个体细胞对旁观者效应的敏感性被认为是由它们的代谢特征决定的。因此，我们进一步假设网络内单个细胞的静息状态将决定对压力的敏感性。 [[这些问题将在来自 ARPE-19 细胞的 RPE 网络以及来自 AMD 的诱导多能干细胞衍生的 RPE 细胞以及具有低和高 AMD 遗传风险因素的对照患者中进行研究]]。在目标 1 中，我们将确定外泌体中包含的信使在 RPE 细胞中执行旁观者效应中的作用。我们已经证明，氧化应激产生的外泌体可以作为信号载体，以补体依赖性方式在供体细胞和受体细胞之间进行通讯。我们将进一步探索这一机制，以确定外泌体形成的极性、外泌体对全局和单细胞反应的活性，以及​​外泌体传递信息的过程。目标 2 旨在确定 GJ 沟通在执行旁观者效应中的效果。我们的初步数据表明，供体细胞中的局部氧化应激可以触发信息传播，导致有限数量的相连受体细胞中线粒体稳态的变化。这一观察将进一步扩展，以确定供体和受体细胞中由局部应激引起的信号事件，以及受体细胞中与对供体细胞信息作出反应的易感性相关的代谢基线参数，并检查介导 GJ 通讯的潜在信使。