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

项目摘要 我们最近发表了关于光诱导的本地生物钟在 视网膜依赖于视蛋白5（Opn 5），并且Opn 5在视网膜神经元的亚群中表达。 神经节细胞（RGCs）。在初步分析中，我们还表明，（1）小鼠 Opn 5突变或时钟基因（Per 2和Bmal 1）具有血管发育 视网膜和玻璃体血管的缺陷，以及（2）使用ChIP-seq分析， 血管调节因子Flt 1和EphrinB 2直接受时钟转录调控 因子BMAL 1。基于这些数据，我们提出了一个模型来解释的机制， OPN 5调节血管发育。在这个模型中，我们认为光 视网膜神经节细胞中OPN 5的刺激首先在内部神经元中产生昼夜节律钟， 视网膜。我们认为，反过来，时钟转录因子BMAL 1直接调节 Flt 1和EphrinB 2的节律性表达。由于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， 调节视网膜血管生成和玻璃体血管消退。我们的核心假设 依赖OPN 5的局部视网膜时钟调节Flt 1的表达， EphrinB 2，反过来，眼睛的光依赖性血管发育。到 研究这个假设，我们提出三个目标。我们将决定何时在 在发育过程中，依赖于OPN 5的视网膜时钟首先活跃（Aim 1），无论视网膜时钟是否活跃， 时钟功能是正常血管发育所必需的（目标2）， EphrinB 2和其他血管介质受OPN 5依赖性视网膜神经元调节。 时钟OPN 5依赖性通路调节血管反应的存在 这是一个不寻常的发现，可能对人类有重要意义。 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.