REGENERATION OF CONE PIGMENTS & TREATMENT OF STARGARDT'S

锥体颜料的再生

• 批准号: 6436654
• 负责人: GABRIEL H TRAVIS
• 金额: $ 38.17万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-03-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6436654
• 关键词: all trans retinol; animal genetic material tag; cone cell; enzyme activity; enzyme therapy; eye disorder chemotherapy; gene mutation; gene targeting; genetically modified animals; immunocytochemistry; laboratory mouse; lipofuscin; macular degeneration; messenger RNA; molecular cloning; molecular pathology; phosphorylation; polymerase chain reaction; protein structure function; regeneration; retinal pigment epithelium; rod cell; tissue /cell culture; visual pathways; visual photoreceptor; visual pigments; yeast two hybrid system

DESCRIPTION (provided by applicant): Vision in civilized man is mediated largely by cone photoreceptors. Despite the importance of cones, much more is known about the biology of rods. The first step in visual perception is absorption of a photon by a visual pigment molecule, which induces 11-cis to all-trans isomerization of the retinaldehyde chromophore. Before light-sensitivity can be restored, all-trans-retinaldehyde must be re-isomerized to 11-cis-retinaldehyde. This involves a multi-step process called the visual cycle, which has been worked out mainly in rod-dominant species. Several lines of published evidence suggest that cone photoreceptors regenerate visual pigment by an alternate pathway. Nothing is known, however, about the biochemistry of this alternate pathway. We have recently identified three new catalytic activities in cone-dominant ground squirrel and chicken retinas that mediate regeneration of 11-cis-retinaldehyde from all-trans-retinol. The first aim of this application will be to purify and clone the mRNA for: (1) a new 11-cis-retinol dehydrogenase distinct from the 11-cis-retinol dehydrogenase type-5 in retinal pigment epithelial cells; (2) an all-trans-retinol isomerase that catalyzes the direct conversion of all-trans-retinol to 11-cis-retinol utilizing fatty-acyl-CoAs as an energy source; and (3) an 11-cis-retinyl-ester synthase that acts by a mechanism clearly distinct from that of lecithin-retinol acyl transferase (LRAT). We plan to characterize these proteins functionally, using in vitro biochemical, cell culture expression, and mouse transgenic/knockout systems. Recessive Stargardt's disease is an inherited form of macular degeneration caused by mutations in the ABCR gene. During the previous funding period, we generated mice with a knockout mutation in abcr. The phenotype in these animals is strikingly similar to the clinical phenotype in patients with recessive Stargardt's disease, including accumulation of lipofuscin in the retinal pigment epithelium. Lipofuscin accumulation appears to be a critical event in the development of retinal pathology. The second aim of this application is to test a promising strategy for inhibiting lipofuscin deposition and photoreceptor degeneration in abcr-/- mice. If successful, this strategy should lead to the initiation of clinical trials on patients with active Stargardt's disease.

描述（由申请人提供）：文明人的视觉是介导的 主要是通过视锥细胞。尽管视锥细胞很重要， 了解杆状生物学。视觉感知的第一步是 视觉色素分子吸收光子，诱导11-顺式， 视黄醛发色团的全反式异构化。之前 光敏感性可以恢复，全反式视黄醇必须 再异构化为11-顺式-视黄醇。这涉及一个多步骤的过程 称为视觉周期，这主要是在杆优势， 物种一些已发表的证据表明，锥状光感受器 通过另一条途径再生视觉色素。然而，目前还不清楚， 关于这种替代途径的生物化学。我们最近发现 三个新的催化活性在锥优势地松鼠和鸡 视网膜介导11-顺式-视网膜醛的再生 全反式视黄醇本申请的第一个目的是纯化和 克隆mRNA：（1）一种新的11-顺式-视黄醇脱氢酶， 视网膜色素上皮细胞11-顺式视黄醇脱氢酶5型; 全反式视黄醇异构酶，催化 利用脂肪酰辅酶A作为能量的全反式视黄醇到11-顺式视黄醇 来源;和（3）11-顺式-视黄基酯合酶，其通过一种机制起作用 与卵磷脂-视黄醇酰基转移酶（LRAT）明显不同。我们计划 为了表征这些蛋白质的功能，使用体外生物化学，细胞 培养表达和小鼠转基因/敲除系统。 隐性Stargardt病是一种遗传性黄斑变性 是由ABCR基因突变引起的在上一个财政年度，我们 产生了abcr基因敲除突变的小鼠。这些动物的表型 与隐性遗传患者的临床表型惊人相似， Stargardt病，包括视网膜中脂褐素的积聚 色素上皮脂褐素积累似乎是一个关键事件， 视网膜病理学的发展。本申请的第二个目的是 测试抑制脂褐质沉积的有希望的策略， abcr-/-小鼠的光感受器变性。如果成功，这一战略将 导致对活跃的Stargardt患者进行临床试验 疾病