Regulation of vascular development in the eye by an opsin 5-dependent clock

项目摘要 我们最近发表了当地生物钟的光夹带现象。 视网膜依赖于视蛋白5(OPN5)，OPN5在视网膜的一个亚群中表达 神经节细胞(RGC)。在初步分析中，我们还表明，(1)小鼠 突变为OPN5或时钟基因(PER2和BMal1)有血管发育 视网膜和玻璃体血管的缺陷，以及(2)使用芯片序列分析， 血管调节因子Flt1和EPhinB2受时钟转录的直接调控 因子BMAL1。基于这些数据，我们提出了一个模型来解释这一机制 哪种OPN5调节血管发育。在这个模型中，我们认为光 刺激视网膜节细胞中的OPN5首先将生物钟带入内侧神经元 视网膜。我们认为，时钟转录因子BMAL1反过来直接调节 Flt1和EPhinB2的节律性表达。因为这些是关键的监管机构 VEGFA(血管内皮生长因子A)反应，这提供了一个直接的联系 视网膜血管生成和玻璃体血管退行性变的调控。我们的中心假设 依赖于OPN5的局部视网膜时钟调节Flt1和Flt1的表达 EPhinB2和，反过来，眼睛的光依赖血管的发育。至 考察这一假说，我们提出了三个目标。我们将确定何时在 发展OPN5依赖的视网膜时钟是第一个活跃的(目标1)，是否视网膜 时钟功能是正常血管发育所必需的(目标2)，以及Flt1， EwitinB2和其他血管介质受依赖于OPN5的视网膜调节 钟。调节血管反应的OPN5依赖通路的存在 眼睛里有一项不同寻常的发现，这可能对人类有重要的影响 血管性视网膜病变。

Project Summary We have recently published that light entrainment of the local circadian clock in the retina is dependent on Opsin 5 (OPN5) and that Opn5 is expressed in a subset of retinal ganglion cells (RGCs). In preliminary analysis we have also shown, (1) that mice mutated for Opn5 or in clock genes (Per2 and Bmal1) have vascular development defects in both the retina and hyaloid vessels, and (2) using ChIP-seq analysis, that the vascular modulators Flt1 and EphrinB2 are directly regulated by the clock transcription factor BMAL1. Based on these data, we propose a model to explain the mechanism by which OPN5 regulates vascular development. In this model we suggest that light stimulation of OPN5 in RGCs first entrains a circadian clock in the neurons of the inner retina. We suggest that in turn, the clock transcription factor BMAL1 directly regulates rhythmic expression of Flt1 and EphrinB2. Since these are crucial regulators of the VEGFA (vascular endothelial growth factor A) response, this provides a direct link to the regulation of retinal angiogenesis and hyaloid vessel regression. Our central hypothesis is that an OPN5-dependent, local retinal clock regulates expression of Flt1 and EphrinB2 and, in turn, light-dependent vascular development of the eye. To investigate this hypothesis, we propose three aims. We will determine when during development the OPN5-dependent retinal clock is first active (Aim 1), whether retinal clock function is required for normal vascular development (Aim 2) and whether Flt1, EphrinB2 and other vascular mediators are regulated by an OPN5-dependent retinal clock. The existence of an OPN5-dependent pathway that regulates vascular responses in the eye is an unusual finding that may have important implications for the human vascular retinopathies.