Photic and Circadian Regulation of Retinal Melatonin

哺乳动物的视网膜含有调节视网膜多方面功能的生物钟。 通过驱动基因表达的昼夜节律，光感受器外节段膜 周转率和视觉敏感度。先前的研究表明，褪黑素通过g蛋白发挥作用。 褪黑素偶联受体(MTRs)在多种视网膜细胞的调节中起着关键作用。 昼夜节律和褪黑素参与了视网膜细胞活性的调节 衰老。在本申请中，我们将进一步调查地铁拆除对 通过使用褪黑激素熟练的小鼠(C3H-f/)小鼠视网膜，在其中两种不同类型的g- 蛋白质偶联褪黑素受体(MTR)已被移除。这些新的动物模型 我们实验室开发的工具提供了一个独特而强大的工具来研究 褪黑素和MTRs在视网膜中的作用。我们的初步数据表明，褪黑素的作用 在一些视网膜细胞内，可能是通过形成褪黑素受体1来调节的 和2个异构体(MTRh)。本申请包括三个具体目标。具体而言 目的1，我们将确定褪黑素受体1型和2型是否形成 视网膜细胞中的异构体。在特定的目标2中，我们将研究褪黑素及其 褪黑素脱盘中相关受体对昼夜节律的调节 熟练小鼠和褪黑激素受体基因敲除小鼠。最后，在具体目标3中，我们将 确定外源性褪黑素是否会增加视网膜的敏感性 通过激活MTRs来诱导光损伤，我们将剖析信号转导途径 在光感受器和RPE细胞中被褪黑素激活。在我们的研究中，我们将使用广泛的 一系列新的和技术先进的技术，如定量实时Q-RT- 聚合酶链式反应、生物荧光共振能量转移、激光捕获解剖 显微镜和微阵列分析。 意义重大。褪黑素及其相关受体的作用特征可能 为褪黑素在眼部和眼部的作用机制提供新的重要见解 更普遍的是，身体的其他部分。在我们的申请中提出的实验将 产生可能导致开发新的治疗工具以治疗或预防的数据 与褪黑激素能系统功能障碍相关的疾病状态。

The mammalian retina contains circadian clocks that regulate multiple aspects of retinal function by driving circadian rhythms of gene expression, photoreceptor outer segment membrane turnover, and visual sensitivity. Previous work has shown that melatonin acting via g protein- coupled melatonin receptors (MTRs) plays a key role in the regulation of a wide variety of retinal circadian rhythms and melatonin is involved in the modulation of retinal cell viability during aging. In the present application we will further investigate the effect of MTR removal on the retina by using melatonin proficient mice (C3H-f+/+) mouse in which the two different types of g- protein coupled melatonin receptors (MTRs) have been removed. These new animal models developed in our laboratory provides a unique and powerful tool with which to investigate the role of melatonin and MTRs in the retina. Our preliminary data suggest that melatonin action within the some retinal cells is likely to be mediated via the formation of melatonin receptor 1 and 2 heteromers (MTRh). The present application comprises three specific aims. In specific aim 1, we will determine whether melatonin receptor type 1 and melatonin receptor type 2 form heteromers in retinal cells. In Specific aim 2, we will investigate the role of melatonin and its associated receptors in the regulation of the daily rhythms in disc shedding in melatonin proficient mice and melatonin receptor knock-out mice. Finally, in specific aim 3 we will determine whether administration of exogenous melatonin increase the sensitivity of the retina to light-induced damage via activation of MTRs and we will dissect the signaling pathways activate by melatonin in the photoreceptor and RPE cells. In our research, we will use a wide array of new and technologically advanced techniques, such as quantitative real time Q-RT- PCR, Bioluminescence Resonance Energy Transfert (BRET), laser capture dissecting microscopy, and microarray analysis. Significance. The characterization of the action of melatonin and its associated receptors may provide new and important insights on the mechanisms of action of melatonin in the eye and more in general in the rest of the body. The experiments proposed in our application will generate data that may lead to the development of new therapeutic tools to treat or prevent disease states associated with dysfunction of the melatonergic system.