Cone Opsin-Ligand Interactions and Photoreceptor Health

这个项目的主要目标是防止视锥感光细胞退化。在疾病中 如Leber先天性巨结肠症(LCA)，天然发色团的水平，II-顺式视网膜，用于 视觉色素缺失或高度减少。视力受损不仅仅是因为缺乏视力 色素的产生，也是因为视锥感光器的丢失。在小鼠LCA模型中，锥体 视色素蛋白(Opsins)高度错位，锥体细胞随后死亡。毁伤 蓝色圆锥体的情况似乎最为严重。这种模式似乎与LCA的发病机制相似。 在这些小鼠的早期黑暗中使用ii-顺式视网膜可以保存更健康的视锥细胞，提示 视蛋白与II-顺式视网膜的结合是防止视锥细胞死亡的重要一步。11的缺点是- 顺式视网膜本身作为一种治疗剂，一旦与视黄素结合，就会被破坏。 暴露在阳光下。这一建议的工作假设是，在没有当地人的情况下 生色团，一种化合物，可以模拟II-顺式视网膜对视锥细胞的影响 Opsins还将模拟细胞对视锥感光细胞的影响。这样做的主要优点是 化合物的特点是，治疗期不需要持续的黑暗条件。在分子水平上， 视锥视蛋白在结构上是活跃的，II-顺式视网膜使视蛋白失活。化合物图书馆 这些是II-顺式视网膜的类似物将被测试它们在关闭人类视锥视蛋白方面的有效性 根据它们激活转导蛋白的能力来判断。能有效抑制视蛋白的化合物将 然后在分离的视锥感光细胞中进行测试，以确保它们对细胞无毒，并且它们 能够使活细胞内的锥体视蛋白失活。被发现符合这些标准的化合物将是 在两种LCA小鼠模型上进行测试，以确定它们是否可以防止锥体的快速退变 通过荧光显微镜和视网膜电描记术判断光感受器细胞。有能力 在患有LCA的患者中保存视锥感光细胞的活性将是关键的一步 恢复视力。

The broad objective of this project is to prevent cone photoreceptors from degenerating. In a disease such as Leber Congenital Amaurosis (LCA), the levels of the native chromophore, ii-cis retinal, for visual pigments is absent or highly reduced. Vision is impaired not only because of a lack of visual pigment generation but also because cone photoreceptors are lost. In a mouse models for LCA, cone visual pigment proteins (opsins) are highly mislocalized and cone cells subsequently die. Damage seems to be most severe with blue cones. This pattern appears to parallel the pathogensis of LCA. Treating these mice with ii-cis retinal at an early age in the dark preserves healthier cones, suggesting that opsin's binding of ii-cis retinal is an important step in preventing cone death. A drawback to 11- cis retinal itself as a therapeutic agent is that it is destroyed once it combines with the opsin and exposed to light. The working hypothesis for this proposal is that in the absence of the native chromophore, chemical compounds that can mimic the effects that ii-cis retinal has on the cone opsins will also mimic the cellular effects on the cone photoreceptors. The main advantage of such compounds is that the treatment period will not require constant dark conditions. At the molecular level, cone opsins are constitutively active, and ii-cis retinal deactivates the opsins. A library of compounds that are analogs of ii-cis retinal will be tested for their effectiveness in turning off human cone opsins as judged by their abilities to activate transducin. Compounds that effectively deactivate the opsins will then be tested in isolated cone photoreceptor cells to ensure they are not toxic to cells and they are able to deactivate cone opsins inside a living cell. Compounds found to meet these criteria will be tested in 2 mouse models of LCA to determine if they can prevent the rapid degeneration of cone photoreceptor cells as judged by fluorescence microscopy and electroretinography. The ability to preserve the viability of cone photoreceptor celis in those afflicted with LCA will be a critical step to restoring visual acuity.