Role of Extracellular Matrix in Retinal Development and Disease

描述(申请人提供)：穆勒细胞(MC)在视网膜动态平衡中起关键作用。它们被极化，顶室面向视网膜下间隙，基面附着于内界膜(ILM)。任何一个隔室的破坏都会导致MC的激活和导致视力丧失的病理生物学后果。层粘连蛋白组织基底膜(BM)，如作为细胞黏附、极性和增殖的附着部位的ILM。我们制造了两个层粘连蛋白基因Lamb2和Lamc3零突变的小鼠，发现这些分子是正常视网膜发育所必需的。Lamb2/c3核的缺陷包括：ILM畸形；MC组织紊乱；光感受器发育不良；以及视网膜内的进行性病理。我们的长期目标是了解层粘连蛋白对MC组织的发展和稳定性的分子贡献，特别是因为它与功能结构有关。我们的近期目标是评估MC-层粘连蛋白相互作用对以下方面至关重要的组织假说：1)建立MC极性；2)维持MC亚细胞组织；3)稳定视网膜的结构完整性。在目标1中，我们将研究MC中层粘连蛋白介导的支架形成的分子机制。我们将回答以下三个问题。首先，我们将解决：MC Basal EndFoot的粘连复合体的分子组织是什么？接下来，我们将确定：层粘连蛋白对离子通道亚细胞定位和功能的依赖是什么？最后，我们将探讨：层粘连蛋白调节MC增殖的机制是什么？在目标2中，我们将检验与层粘连蛋白底物的粘附性丧失破坏视网膜内部正常结构/功能关系的推论假说。我们的数据显示，Lamb2/c3缺失的动物在IPL中有选择性的中断。我们将回答以下问题。首先，我们将问：在IPL中，层粘连蛋白对树突状细胞形成的依赖性是什么？接下来，我们将讨论：Lamb2/Lamc3缺陷区进行性视网膜神经节细胞丢失的机制是什么？这些实验及其揭示的分子机制将有助于我们理解胶质细胞增生症、增殖性玻璃体视网膜病变和先天性眼病(包括Walker-Warburg、Bardet-Biedl、Pierson综合征)的病理生理学。 与公共卫生相关：先天出生缺陷影响数百万美国人和世界各地的人。这些疾病包括肌肉营养不良、导致智力低下和失明的大脑和眼睛疾病。该项目调查了其中几种疾病的原因，结果将导致新的诊断和治疗方法。

DESCRIPTION (provided by applicant): The Muller cells (MCs) have a key role in retinal homeostasis. They are polarized with an apical compartment facing the subretinal space, and a basal surface adhering to the inner limiting membrane (ILM). Disruption of either compartment leads to activation of MCs and pathobiological consequences leading to vision loss. Laminins organize basement membranes (BM), such as the ILM serving as attachment sites for cell adhesion, polarity and proliferation. We produced mice with null mutations in two laminin genes, Lamb2 and Lamc3, and found that these molecules are necessary for normal retinal development. The defects in the Lamb2/c3 nulls include: ILM malformation; MC disorganization; photoreceptor dysgenesis; and progressive pathology in the inner retina. Our long-range goal is to understand the molecular contributions of laminin to the development and stability of MC organization, in particular, as it relates to the functional architecture. Our immediate goal is to assess the organizing hypothesis that MC-laminin interactions are critical for: 1) establishing MC polarity; 2) maintaining MC sub cellular organization and 3) stabilizing the structural integrity of the retina. In Aim 1, we will examine the molecular mechanisms underlying laminin- mediated scaffolding in the MC. We will answer the following three questions. First, we will address: What Is The Molecular Organization Of The Adhesion Complex Of The MC Basal Endfoot? Next, we will determine: What Is The Laminin Dependence Of Ion Channel Sub cellular Localization And Function? Finally, we will investigate: What Is The Mechanism Of Laminin Regulation Of MC Proliferation? In Aim 2, we will examine the corollary hypothesis that the loss of adhesion to laminin substrates disrupts the normal structure/function relationships in the inner retina. Our data show that the Lamb2/c3 null animals have selective disruptions in the IPL. We will answer the following questions. First, we will ask: What Is The Laminin Dependence Of Dendritogenesis In The IPL? Next, we will address: What Are The Mechanisms Of Progressive Retinal Ganglion Cell Loss in Lamb2/Lamc3 nulls? These experiments and the molecular mechanisms they reveal will contribute to our understanding of the pathophysiology of gliosis; proliferative vitreoretinopathy and congenital ocular disorders including Walker-Warburg, Bardet-Biedl, Pierson Syndrome. PUBLIC HEALTH RELEVANCE: Congenital birth defects affect millions of Americans and people world-wide. These diseases include muscular dystrophy, brain and eye disorders leading to mental retardation and blindness. This project investigates the cause of several of these diseases and the results will lead to new diagnostics and therapeutics.