权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Norrin/Frizzled4 Signaling in Retinal Angiogenesis: The Role of TSPAN12

Norrin/Frizzled4 信号在视网膜血管生成中的作用：TSPAN12 的作用

基本信息

批准号：
9042369
负责人：
Harald Junge
金额：
$ 36.92万
依托单位：
UNIVERSITY OF COLORADO
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-04-01 至 2019-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9042369
关键词：
Affect Binding Biological Assay Biological Models Biology Blindness Blood Blood Vessels Blood capillaries Bypass Cells Chimera organism Complex Cre-LoxP Defect Development Dimerization Disease Distant Endothelial Cells Exudative age-related macular degeneration Eye Development Family Genes Genetic Genetic study Goals Health Homo Human Genetics Immunoprecipitation In Vitro Inherited Integral Membrane Protein Investigation Lead Ligands Ligation Lipoprotein Receptor Luciferases Mediating Mediator of activation protein Membrane Proteins Modeling Molecular Molecular Genetics Morphogenesis Muller&apos s cell Mus Mutant Strains Mice Mutation Neurons Norrie&apos s disease Pathway interactions Patients Pattern Pericytes Phenocopy Phenotype Play Point Mutation Proteins Reporter Reporting Retina Retinal Retinal Diseases Role Signal Pathway Signal Transduction System Tacrolimus Binding Proteins Testing Therapeutic Intervention Vascular Diseases Vascular Endothelial Cell Vascularization Vision Visual impairment base capillary cell type in vivo loss of function member neovascular novel programs proliferative diabetic retinopathy receptor receptor binding research study response retina blood vessel structure retinal angiogenesis retinal progenitor cell targeted treatment trafficking

项目摘要

DESCRIPTION (provided by applicant): Our overall objective is to understand retinal angiogenesis in a context of development and ocular disease, using mice as a model system. Retinal vascular diseases, including proliferative diabetic retinopathy and neovascular age related macular degeneration, are major causes of impaired vision and blindness. One of the central angiogenic signaling pathways in the retina is Norrin/Frizzled4 signaling. Norrin signals via its receptor Frizzled4 and the co-receptor LRP5 on vascular endothelial cells to activate ß-catenin signaling and transcriptional programs. The pathway plays a critical role in instructing retinal vascular morphogenesis and blood-retina barrier formation. Impaired Norrin/Frizzled4 signaling causes familial exudative vitreoretinopathy, an inherited disease that can cause blindness. The focus of this application is on the membrane protein TSPAN12, a novel and essential component of Norrin/Frizzled4 signaling. Tspan12 gene disrupted mice phenocopy norrin and frizzled4 mutant mice, and TSPAN12 is a strong facilitator of Norrin/Frizzled4 signaling in cell-based assays. We have three objectives: i) We hypothesize that TSPAN12 is functionally required in retinal endothelial cells and that restricted TSPAN12 expression modulates the spatio-temporal pattern of pathway activation. This model predicts that conditional disruption of the tspan12 gene in endothelial cells, but not in other cell types, recapitulates the loss-of-function phenotypes, e.g., lack of intraretinal capillaries and impaired blood-retina barrier integrity. We will use the Cre-Lox system to test this model. ii) TSPAN12 is required only in Norrin-induced but not in Wnt-induced Frizzled4 signaling. This is an intriguing and unexplained feature of Norrin/Frizzled4 signaling. We hypothesize that Norrin cannot efficiently induce protein interactions in the Norrin receptor complex and therefore operates together with TSPAN12. In contrast, Wnts may induce the required protein interactions autonomously (e.g., Norrin and Wnts differ in their ability to bind receptor and co-receptor simultaneously). We will test this hypothesis by characterizing protein interactions in the Norrin receptor complex, by determining which interactions are promoted by Norrin, Wnt3a, and TSPAN12, and by determining the consequences of abolishing or forcing relevant protein interactions in cell-based reporter assays. iii) Several recent human genetic studies independently reported mutations in tspan12 in patients with familial exudative vitreoretinopathy. We will determine if the reported mutations impair the function of TSPAN12 in Norrin/Frizzled4 signaling. Building on our investigation of TSPAN12 protein interactions, we will ask if one or several of the mutations impair critical protein interactions of TSPAN12. We will also determine if one or several of the mutations impair the folding or trafficking of TSPAN12. Conclusion: Norrin/Frizzled4 signaling is under investigation as a target for therapeutic intervention. A refined mechanistic model of TSPAN12 function in Norrin/Frizzled4 signaling should aid efforts to target this pathway in neovascular diseases of the retina.

描述（由申请人提供）：我们的总体目标是使用小鼠作为模型系统来了解发育和眼部疾病背景下的视网膜血管生成。视网膜血管疾病，包括增殖性糖尿病视网膜病变和新生血管性年龄相关性黄斑变性，是视力受损和失明的主要原因。视网膜中的中央血管生成信号通路之一是 Norrin/Frizzled4 信号通路。 Norrin 通过其受体 Frizzled4 和血管内皮细胞上的辅助受体 LRP5 发出信号，激活 ß-catenin 信号传导和转录程序。该通路在指导视网膜血管形态发生和血视网膜屏障形成中发挥着关键作用。 Norrin/Frizzled4 信号传导受损会导致家族性渗出性玻璃体视网膜病变，这是一种可导致失明的遗传性疾病。该应用的重点是膜蛋白 TSPAN12，它是 Norrin/Frizzled4 信号传导的新型重要组成部分。 Tspan12 基因破坏了 Norrin 和 frizzled4 突变小鼠的表型，并且 TSPAN12 是基于细胞的检测中 Norrin/Frizzled4 信号传导的强促进剂。我们有三个目标：i) 我们假设 TSPAN12 在视网膜内皮细胞中是功能所必需的，并且限制 TSPAN12 表达可调节通路激活的时空模式。该模型预测，内皮细胞（而非其他细胞类型）中 tspan12 基因的条件性破坏会重现功能丧失的表型，例如视网膜内毛细血管的缺乏和血视网膜屏障完整性受损。我们将使用 Cre-Lox 系统来测试该模型。 ii) TSPAN12 仅在 Norrin 诱导的信号传导中需要，但在 Wnt 诱导的 Frizzled4 信号传导中不需要。这是 Norrin/Frizzled4 信号传导的一个有趣且无法解释的特征。我们假设 Norrin 不能有效诱导 Norrin 受体复合物中的蛋白质相互作用，因此与 TSPAN12 一起发挥作用。相反，Wnts 可以自主诱导所需的蛋白质相互作用（例如，Norrin 和 Wnts 同时结合受体和共受体的能力不同）。我们将通过表征 Norrin 受体复合物中的蛋白质相互作用，确定 Norrin、Wnt3a 和 TSPAN12 促进哪些相互作用，以及确定在基于细胞的报告基因测定中废除或强制相关蛋白质相互作用的后果来检验这一假设。 iii) 最近的几项人类遗传学研究独立报告了家族性渗出性玻璃体视网膜病变患者的 tspan12 突变。我们将确定报告的突变是否会损害 TSPAN12 在 Norrin/Frizzled4 信号传导中的功能。基于我们对 TSPAN12 蛋白质相互作用的研究，我们将询问一个或多个突变是否会损害 TSPAN12 的关键蛋白质相互作用。我们还将确定一个或多个突变是否会损害 TSPAN12 的折叠或运输。结论：Norrin/Frizzled4 信号传导正在作为治疗干预的目标进行研究。 Norrin/Frizzled4 信号传导中 TSPAN12 功能的精细机制模型应有助于针对视网膜新生血管疾病中的这一通路。