MOLECULAR BIOLOGY OF DIABETIC CATARACT FORMATION

糖尿病性白内障形成的分子生物学

• 批准号: 6518340
• 负责人: Patrick Ross Cammarata
• 金额: $ 25.41万
• 依托单位: UNIVERSITY OF NORTH TEXAS HLTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 2005-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6518340
• 关键词: aldehyde reductase; chloride channels; diabetic cataract; diacylglycerols; disease /disorder model; gene expression; genetically modified animals; immunoelectron microscopy; laboratory mouse; lens; membrane transport proteins; model design /development; northern blottings; osmotic pressure; pathologic process; polymerase chain reaction; sodium; taurine; tissue /cell culture

DESCRIPTION (Adapted from applicant's abstract): Diabetic cataract is a significant and costly worldwide health problem. Intracellular osmotic stress has been implicated in the etiology of diabetic cataract. The definition of the sequence of basic molecular and cellular processes leading to the complications of diabetic cataract have yet to be established. The accumulation of organic osmolytes (sorbitol, myo-inositol, taurine) normally protects the lens against osmotic imbalance by maintaining intracellular osmotic homoeostasis. In the course of maintaining lens homeostasis, the lens epithelial layer preserves itself by utilizing several osmotic compensatory mechanisms, whereas the subjacent fiber cells, likely because of a diminished capacity to osmoregulate, swell and bleb. To obtain a realistic view of the pathophysiological impact of osmotic stress on diabetic cataract formation, a novel transgenic animal model has been developed useful to exploring the pathogenesis and therapy of osmotic cataractogenesis. We have successfully introduced the bovine sodium/myo-inositol cotransporter gene (bSMIT) in several mouse lines and have shown the transgene is functionally expressed in developing lens fibers. Lens fiber swelling and consequent cataractous formation provide a physiological surrogate that simulates the progression of human diabetic cataract. Careful scrutiny of mouse lens regional development and early-onset swelling allows for verification of the hypothesis that the lens fibers are incapable of osmoregulation. The molecular biology and the pathophysiology of the transgenic mouse model exhibiting diabetic cataract will be linked by correlating the level of bSMIT gene expression via in situ hybridization and coupled reverse transcription/polymerase chain reaction with the intralenticular content of free myo-inositol. Lens morphology will be followed by light and electron microscopic evaluation of transgenic and nontransgenic littermates using embryonic lenses up through lenses from six month-old mice. Low transgene-expressing mice, which do not form lens opacities with normal rearing and diet, will be made to do so with a myo-inositol supplemented diet. The determination of the sequence of events in the pathophysiology of diabetic cataract formation will identify sites of intervention and allow for the development of innovative pharmacological agents to prevent or halt the progression of diabetic cataract. One such intervention is to activate chloride channels, which enhances both chloride exit and myo-inositol efflux. This study proposes to test the potential usefulness of enhancing myo-inositol efflux through chloride channels as a means for drug therapy to relieve intrafiber osmotic stress.

描述（改编自申请人的摘要）：糖尿病性白内障是一种 重大且昂贵的全球健康问题。细胞内渗透应激 与糖尿病性白内障的病因有关。定义 基本分子和细胞过程的顺序导致并发症 糖尿病性白内障尚未确定。有机的积累 Osmolytes（山梨糖醇，肌醇，牛磺酸）通常会保护镜头免受 通过维持细胞内渗透常恒性，渗透失衡。在 维持镜头稳态的过程，镜头上皮层保留 通过利用几种渗透补偿机制，而 纤维细胞的次级纤维细胞，可能是由于osgoregulate的能力降低， 膨胀和泡沫。为了获得对病理生理影响的现实看法 糖尿病性白内障形成的渗透压，一种新型的转基因动物模型 已经开发用于探索渗透的发病机理和治疗 白内生生成。我们已经成功介绍了牛 钠/肌醇 - 肌醇共转运蛋白基因（BSMIT）在几种小鼠系中，具有 显示转基因在发育中的晶状体纤维中表达。镜片 纤维肿胀和随之而来的白内障形成提供生理 替代人模拟人类糖尿病性白内障的进展。小心 仔细检查鼠标镜头区域发展和早发肿胀允许 验证镜头纤维无能的假设 渗透调节。转基因的分子生物学和病理生理学 表现出糖尿病性白内障的小鼠模型将通过关联 Bsmit基因表达水平通过原位杂交和反向耦合 转录/聚合酶链链反应与内内含量 免费的肌醇。镜头形态之后将是光和电子 使用转基因和非转基因同窝仔的微观评估 通过六个月大的小鼠的镜头向上胚胎镜头。低的 表达转基因的小鼠，它们不会形成正常饲养的镜头不透明 和饮食将通过补充肌醇的饮食来做到这一点。这 确定糖尿病病理生理学中事件序列 白内障形成将确定干预部位，并允许 开发创新的药理学剂，以防止或停止 糖尿病性白内障的进展。一种这样的干预是激活氯化物 通道，可以增强氯化物出口和肌醇外排。这项研究 提议测试增强肌醇外排的潜在实用性 通过氯化物通道作为药物治疗的一种缓解次临床的手段 渗透压。