Retinal Microglia and Angiogenesis

描述（由申请人提供）：血管系统在发育、稳态和疾病中起着至关重要的作用。有了预定的血管退化（玻璃体血管）和小鼠出生后血管生成（视网膜）的例子，眼睛是研究血管发育的绝佳结构。在本申请中，我们提出研究视网膜小胶质细胞，一种髓样细胞，在视网膜神经细胞的调节中的作用。 血管生成基于已发表的和初步的研究，我们提出了视网膜小胶质细胞通过产生VEGF以及通过Wnts和可能的Notch，VEGF抑制剂Flt 1来调节血管模式的假设。我们提出了三个目的来研究这一假说：（1）确定小胶质细胞或Muller胶质细胞VEGF是否介导了深层视网膜血管生成的有吸引力的指导。已发表的研究表明，Muller胶质细胞产生VEGF，我们的初步研究表明，小胶质细胞也产生VEGF。这是VEGF的两个可能来源，可能作为下行血管生成芽的有吸引力的指导线索。(2)确定小胶质细胞的非经典Wnt-Flt 1反应是否为Wnt-cGMP/Ca 2+通路。我们的初步研究表明，非经典的Wnt-cGMP/Ca ~（2+）途径参与了小胶质细胞Flt 1的产生。我们将在培养试验中使用药理学抑制剂并通过评估途径组分的遗传缺失的体内后果来进一步评估这些。(3)确定小胶质细胞Notch反应是否上调Flt 1并与Wnt通路整合。已发表的工作和初步研究表明，血管内皮细胞和小胶质细胞都显示出Flt 1的Notch依赖性上调。这提出了当血管生成尖端细胞（在深血管层中表达Notch配体Dll 4）与小胶质细胞接触时，Flt 1上调的可能性。鉴于Wnt也调节Flt 1表达，这也表明Wnt和Notch途径必须整合。这些研究在揭示血管生成正常调节的基本机制方面很重要，因此，揭示了血管生长和消退可能在治疗上受到调节的新方法。特别是，这项工作对影响视力的疾病糖尿病视网膜病变，年龄相关性黄斑变性和早产儿视网膜病变有影响。

DESCRIPTION (provided by applicant): The vascular system plays a fundamentally important role in development, homeostasis and disease. With examples of scheduled vascular regression (the hyaloid vessels) and in the mouse, postnatal angiogenesis (in the retina), the eye is an excellent structure in which to study vascular development. In this application, we propose to study to role of retinal microglia, a type of myeloid cell, in the regulation of retinal angiogenesis. Based on published and preliminary studies, we propose the hypothesis that Retinal microglia regulate vascular pattern by producing VEGF and, via Wnts and possibly Notch, the VEGF inhibitor Flt1. We propose three aims to investigate this hypothesis: (1) to determine whether microglial or Muller glial VEGF mediates attractive guidance for deep layer retinal angiogenesis. Published work shows that Muller glia makes VEGF and our Preliminary Studies show that microglia also do. These are two possible sources of VEGF that might act as an attractive guidance cues for descending angiogenic sprouts. (2) To determine whether the non-canonical Wnt-Flt1 response of microglia is the Wnt-cGMP/Ca2+ pathway. Our Preliminary Studies suggest that the non-canonical Wnt-cGMP/Ca2+ pathway are involved in the production of Flt1 by microglia. We will further assess these using pharmacological inhibitors in a culture assay and by assessing the in vivo consequences of genetic deletion of pathway components. (3) To determine whether a microglial Notch response up-regulates Flt1 and integrates with the Wnt pathway. Published work and Preliminary Studies show that both VECs and microglia show Notch-dependent up-regulation of Flt1. This raises the possibility that when angiogenic tip cells (that express the Notch ligand Dll4 in the deep vascular layer), make contact with microglia, there is an up-regulation of Flt1. Given that Wnts also regulate Flt1 expression, it also suggests that the Wnt and Notch pathways must be integrated. These studies are important in uncovering basic mechanisms by which angiogenesis is normally regulated and as a result, uncovering new ways in which blood vessel growth and regression might be regulated therapeutically. In particular, this work has implications for the vision-compromising ailments diabetic retinopathy, age-related macular degeneration and retinopathy of prematurity.