APOLIPOPROTEIN ISOFORMS AND RETINAL DEGENERATION

描述（由申请人提供）：本研究的长期目标是了解视网膜中载脂蛋白的生物学，特别是特定apoE亚型可能发挥（或缺乏）神经保护作用的机制。这个为期2年的探索性项目的近期目标是开发和表征所需的基因改变小鼠品系，以实现长期目标。ApoE是参与胆固醇代谢和转运的蛋白质。在脑中，apoES同种型被认为是神经保护性的，并在CNS损伤后的恢复中发挥重要作用。相比之下，apoE 4亚型是痴呆症（如阿尔茨海默病）的危险因素。奇怪的是，在年龄相关性黄斑变性（AMD）中似乎存在完全相反的趋势，其中apoE 4与疾病发生率降低相关。这个悖论的原因仍然是一个谜，需要适当的新模型系统来阐明所涉及的分子机制。作为实现这一目标的第一步，我们将开发新的小鼠品系，并评估apoE是否可以以同种型特异性方式调节遗传性视网膜变性的严重程度和时间进程。携带rds（视网膜变性缓慢）突变且缺乏apoE基因的突变小鼠将与选择性表达人apoES或apoE 4同种型的小鼠杂交。将通过PCR确认基因型。使用Western印迹分析和免疫细胞化学，与年龄匹配的rds和非转基因（野生型）对照小鼠相比，将ApoE表达作为年龄的函数进行评估。将通过光学和电子显微镜评估视网膜变性;将通过视网膜电图（ERG）评估视网膜功能。本研究的临床相关性在于调节视网膜中apoE的神经保护性同种型的表达作为延缓或改善各种起源的人视网膜变性的新疗法的潜力。因此，该项目有可能影响NEI的使命的几个方面：帮助预防和治疗眼疾和其他视力障碍;减少视力障碍和失明;提高所有年龄段人群的生活质量;并提高我们对视觉系统如何在健康和疾病中发挥作用的认识。

DESCRIPTION (provided by applicant): The long-range goal of this study is to understand the biology of apolipoproteins in the retina, particularly the mechanism by which specific apoE isoforms may exert (or lack) neuroprotective effects. The immediate goal of this 2-year exploratory project is to develop and characterize the requisite genetically altered mouse strains to pursue the long-range goal. ApoE is a protein involved in cholesterol metabolism and transport. In the brain, the apoES isoform is thought to be neuroprotective and to play an important role in recovery following CNS injury. In contrast, the apoE4 isoform is a risk factor for dementias, such as Alzheimer's disease. Paradoxically, the exact opposite trend seems to prevail in age-related macular degeneration (AMD), where apoE4 correlates with reduced incidence of disease. The reason for this paradox remains a mystery, and will require appropriate new model systems to elucidate the molecular mechanisms involved. As a first step toward that goal, we will develop novel mouse strains and assess whether apoE can modulate the severity and time course of hereditary retinal degeneration in an isoform-specific manner. Mutant mice harboring the rds (retinal degeneration slow) mutation and lacking the apoE gene will be cross-bred with mice that selectively express either the human apoES or apoE4 isoform. Genotype will be confirmed by PCR. ApoE expression will be assessed as a function of age using Western blot analysis and immunocytochemistry, in comparison with age-matched rds and non-transgenic (wild-type) control mice. Retinal degeneration will be assessed by light and electron microscopy; retinal function will be assessed by electroretinography (ERG). The clinical relevance of this study lies in the potential to modulate the expression of neuroprotective isoforms of apoE in the retina as a novel therapy to retard or ameliorate human retinal degenerations of various origins. As such, this project has the potential to impact several aspects of the NEI's mission: to help prevent and treat eye diseases and other disorders of vision; reduce visual impairment and blindness; improve the quality of life for people of all ages; and advance our knowledge of how the visual system functions in health and disease.