Cone Opsin-Ligand Interactions and Photoreceptor Health

该项目的主要目标是防止锥状光感受器退化。疾病中 例如Leber先天性黑蒙（LCA），天然发色团ii-顺式视网膜的水平， 视觉色素缺失或严重减少。视力受损不仅是因为缺乏视觉 色素生成，但也因为锥光感受器丢失。在LCA小鼠模型中， 视色素蛋白（视蛋白）高度错误定位，并且视锥细胞随后死亡。损害 似乎对蓝色视锥细胞最为严重。这种模式似乎与LCA的发病机制相似。 在黑暗中用ii-顺式视黄醇治疗这些小鼠，可以保持更健康的视锥细胞，这表明 视蛋白与II-顺式视黄醛的结合是防止视锥死亡的重要步骤。11的缺点- 顺式视黄醇本身作为治疗剂的一个缺点是，一旦它与视蛋白结合就被破坏， 暴露在光下。这个建议的工作假设是，在没有本地人的情况下， 发色团，可以模拟II-顺式视黄醛对视锥细胞的作用的化合物 视蛋白也将模拟对视锥光感受器的细胞效应。这样做的主要优点是 该化合物的优点在于处理期将不需要恒定的黑暗条件。在分子水平上， 视锥细胞视蛋白是组成型活性的，而II-顺式视黄醇使视蛋白失活。化合物库 将测试它们在关闭人视锥细胞视蛋白中的有效性 这是通过它们激活转导素的能力来判断的。有效灭活视蛋白的化合物将 然后在分离的视锥光感受器细胞中进行测试，以确保它们对细胞无毒， 能够使活细胞内的视锥蛋白失活。发现符合这些标准的化合物将被 在2种LCA小鼠模型中进行测试，以确定它们是否可以防止视锥细胞的快速退化。 通过荧光显微镜和视网膜电图判断感光细胞。的能力 保护LCA患者的视锥细胞的活力将是关键的一步， 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.