HTRA1 and Age-Related Macular Degeneration

HTRA1 和年龄相关性黄斑变性

• 批准号: 8440650
• 负责人: KANG ZHANG
• 金额: --
• 依托单位: VA SAN DIEGO HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-10-01 至 2017-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8440650
• 关键词: Affinity; Age related macular degeneration; Antibodies; Atrophic; Binding; Blood Vessels; Bruch' s basal membrane structure; Cells; Choroidal Neovascularization; Chromosomes; Complement Factor H; Complex; Data; Development; Diagnostic; Disease; Down-Regulation; ERG gene; Early Intervention; Elderly; Environmental Risk Factor; Evolution; Extracellular Matrix; Family; Funding; Gene Expression; Generations; Genes; Genetic; Genetic Predisposition to Disease; Genetic Risk; Genotype; Haplotypes; High temperature of physical object; Histology; Human; Immunoglobulin Variable Region; Immunohistochemistry; In Vitro; Knock-out; Knockout Mice; Lasers; Lead; Link; Modeling; Molecular; Molecular Profiling; Monoclonal Antibodies; Mus; Ophthalmoscopy; Pathogenesis; Pathology; Pathway interactions; Play; Predisposition; Proteins; Public Health; Regulation; Retina; Retinal; Risk; Role; Scanning; Signal Pathway; Signal Transduction; Single Nucleotide Polymorphism; Social Impacts; Specificity; Structure of retinal pigment epithelium; TGFBR1 gene; Technology; Testing; Therapeutic; Tissues; Transforming Growth Factor beta; Transforming Growth Factor beta Receptors; Transgenic Mice; Transgenic Organisms; United States; Up-Regulation; VEGFA gene; Vascular Endothelial Growth Factors; Visual impairment; Western Blotting; angiogenesis; gene therapy; genetic association; genetic variant; growth differentiation factor 6; insight; loss of function; member; novel; photoreceptor degeneration; public health relevance; receptor; research study; risk variant

DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is the most common cause of visual impairment of the elderly in the United States. We have previously identified a genetic variant in the chromosome region of HTRA1/ARMS2 was associated with major susceptibility to AMD. This disease genotype results in increased expression of high temperature requirement factor A1 (HTRA1). In our previous funding period, we systematically scanned all single nucleotide polymorphisms (SNPs) related to AMD and investigated their regulation of expression of HTRA1 and ARMS2. Our functional study reveals loss of HTRA1 leads to decreased retinal vascular development and significant down-regulation of vascular endothelial growth factor (VEGF) gene expression in HTRA1 knockout (htra1-/-) mice. Conversely, we show Increased expression of HTRA1 in RPE leads to Bruch's membrane pathology and elevated VEGF expression. We further revealed that the up-regulation of VEGF by HTRA1 is inversely correlated to the down-regulation of a member of the TGF-b family, the growth differentiation factor 6 (GDF6). The long term objectives of this proposal are to characterize the normal function of HTRA1, elucidate molecular mechanism by which HTRA1 contributes increased risk of AMD, and development potential therapies. Our central hypothesis is that HTRA1 contributes to AMD risk by regulation of vascular development, angiogenesis, TGF-b signaling, and extracellular matrix modeling. Guided by this hypothesis, we propose to conduct the following specific aims. Specific Aim 1: Generation of monoclonal antibodies to HTRA1 and investigating their therapeutic potential by tissue specific delivery into the RPE cells. Increased HTRA1 expression induced PCV and retinal pigment epithelium atrophy and photoreceptor degeneration. We will generate monoclonal antibodies specifically bind to HTRA1. The selected antibody strains with the high affinity to HTRA1 will be converted into a single chain format (scFv), which will be further "evolved" to maximize binding specificity and affinity using a state-of-the-art novel protein in vitro evolution technology. We will use a gene therapy strategy to deliver such optimized HTRA1 antibodies into RPE and test its effect on inhibition in HTRA1 transgenic mice and a laser-CNV model. Specific Aim 2: To determine the role of TGF-b signal pathway in retinal development and pathology. We show that GDF6 significantly associated with AMD and demonstrated that the GDF6 AMD risk allele is associated with decreased expression of the GDF6 and increased expression of HTRA1. We also showed that TGF-b receptor 1 (TGF-b R1) is associated with AMD. We will generate conditional knockout mice which delete GDF6 and TGF-b R1 in either retina or RPE to examine the role of TGF-b signal pathway in retinal development and pathogenic changes, including ophthalmoscopy, histology, ERG, and expression profile, immunohistochemistry and choroidal neovascularization (CNV) formation. PUBLIC HEALTH RELEVANCE: AMD represents a major public health burden with economical and social impacts. Identification and functional studies of genes that have substantial impact on the risk of AMD may define key molecular pathways involved in its pathogenesis. The experiments we propose will yield novel mechanistic insight relevant to the pathogenesis of both early and late AMD, which may lead to therapies directed at the underlying cause and pre-symptomatic diagnostics to allow for earlier intervention with those therapies.

描述(由申请人提供)： 老年性黄斑变性(AMD)是美国老年人视力受损的最常见原因。我们以前已经发现HTRA1/ARMS2染色体区域的一个遗传变异与AMD的主要易感性有关。这种疾病的基因型导致高温需要因子A1(HTRA1)的表达增加。在我们之前的资助期间，我们系统地扫描了所有与AMD相关的单核苷酸多态(SNPs)，并研究了它们对HTRA1和ARMS2表达的调节。我们的功能研究显示，在HTRA1基因敲除(HTRA1-/-)小鼠中，HTRA1基因缺失导致视网膜血管发育减少，血管内皮生长因子(VEGF)基因表达显著下调。相反，我们发现HTRA1在RPE中的表达增加导致Bruch‘s膜病理和VEGF的表达增加。我们进一步发现，HTRA1上调血管内皮生长因子与下调生长分化因子6(GDF6)的表达呈负相关。这项建议的长期目标是描述HTRA1的正常功能，阐明HTRA1导致AMD风险增加的分子机制，并开发潜在的治疗方法。我们的中心假设是，HTRA1通过调节血管发育、血管生成、转化生长因子-b信号和细胞外基质建模而导致AMD风险。在这一假设的指导下，我们建议进行以下具体目标。具体目的1：制备抗hTRA1的单抗，并通过组织特异性导入RPE细胞来研究其治疗潜力。HTRA1表达增加导致PCV和视网膜色素上皮萎缩，感光细胞变性。我们将产生与HTRA1特异结合的单抗。对HTRA1具有高亲和力的选定抗体株将被转化为单链形式(ScFv)，并将利用最先进的新型蛋白质体外进化技术进一步“进化”，以最大限度地提高结合特异性和亲和力。我们将使用基因治疗策略将这种优化的HTRA1抗体导入RPE，并在HTRA1转基因小鼠和激光-CNV模型中测试其抑制作用。具体目的2：探讨转化生长因子-β信号通路在视网膜发育和病理中的作用。我们发现GDF6与AMD显著相关，并证明GDF6 AMD风险等位基因与GDF6表达降低和HTRA1表达增加相关。我们还发现转化生长因子-β受体1(转化生长因子-β受体1)与AMD有关。我们将建立条件性基因敲除小鼠，删除视网膜或RPE中的GDF6和转化生长因子-b R1，以检测转化生长因子-b信号通路在视网膜发育和病因性变化中的作用，包括眼底镜、组织学、ERG、表达谱、免疫组织化学和脉络膜新生血管(CNV)的形成。 公共卫生相关性： AMD是一个具有经济和社会影响的主要公共卫生负担。对AMD风险有重大影响的基因的鉴定和功能研究可能确定其发病机制中的关键分子途径。我们提出的实验将产生与早期和晚期AMD的发病机制相关的新的机制洞察力，这可能导致针对潜在原因的治疗和症状前诊断，以允许使用这些治疗的早期干预。