The Role of the Nicotinic Cholinergic Pathway in Retinopathy of Prematurity

早产儿视网膜病变（ROP）是世界上儿童视力损害和失明的主要原因。 美国，由于病理性视网膜新生血管。我们发现了一种新的血管生成途径 与病理性新生血管形成有关。该途径由内皮烟碱受体介导。 乙酰胆碱受体（nAChR）。内皮nAChR是一种配体门控阳离子通道， 内源性信号分子乙酰胆碱（ACh）。该受体的激活诱导内皮细胞 有丝分裂、迁移和管形成并促进血管生成。该途径被以下物质上调： 缺氧和其他血管生成因子如血管内皮生长因子（VEGF）。因此，委员会认为， 我们提出以下具体目标来开发用于ROP的新疗法： 1.表征发育中视网膜的内皮烟碱胆碱能通路，并确定其 在正常血管形成中的作用。我们假设视网膜的正常发育不会对 受EC nAChR的药理学拮抗作用的影响。这一假设部分是基于正常的 7-nAChR缺陷小鼠的表型。我们将开始确定，在正常的发展， nAChR途径关键元件的表达和定位水平，包括高亲和力胆碱 转运蛋白、胆碱乙酰转移酶和nAChR亚单位。我们将研究正常视网膜血管的EC 采用激光捕获显微切割和真实的实时RT-PCR、原位杂交和免疫组化技术。 我们将仔细评估血管和神经元的发展在视网膜的<$7-nAChR缺陷小鼠。 最后，我们将确定眼睛中nAChR的药理学拮抗作用（与非选择性的 相对于7-nAChR选择性拮抗剂）将不利地影响正常神经元或血管发育。 2.确定是否该途径的过度激活有助于视网膜新生血管形成， ROP的鼠模型，使用EC nAChR的药理学和遗传敲低。使用 通过上述方法，我们将确定视网膜新生血管形成是否与视网膜新生血管增加有关。 nAChR通路的任何组分的表达。我们将决定是否管理非选择性 （美加明）或<$7-优先（甲基利卡尼汀）nAChR拮抗剂抑制视网膜 新生血管形成将通过ERG评估nAChR拮抗剂对视网膜神经元功能的影响。 将在<$7- nAChR敲除小鼠和同窝对照中诱导ROP，以确定是否通过<$7-nAChR的信号传导。 nAChR有助于视网膜新生血管形成。我们将进行生化研究，以评估 血浆和视网膜ACh水平之间的关系，并将这些水平与视网膜ACh水平的变化相关联。 血管内皮生长因子（VEGF），视网膜血管和渗透性。

Retinopathy of prematurity (ROP), is a leading cause of vision impairment and blindness in children in the United States, due to pathological retinal neovascularization. We have discovered a novel angiogenic pathway that is involved in pathological neovascularization. This pathway is mediated by an endothelial nicotinic acetylcholine receptor (nAChR). The endothelial nAChR is a ligand-gated cationic channel that is activated by the endogenous signaling molecule, acetylcholine (ACh). Activation of this receptor induces endothelial cell mitogenesis, migration and tube formation and promotes angiogenesis. The pathway is upregulated by hypoxia, and by other angiogenic factors such as the vascular endothelial growth factor (VEGF). Accordingly, we propose the following Specific Aims to develop a novel therapy for ROP: 1. Characterize the endothelial nicotinic cholinergic pathway in the developing retina, and determine its role in normal vascularization. We hypothesize that normal development of the retina will not be adversely affected by pharmacological antagonism of the EC nAChRs. This hypothesis is based in part on the normal phenotype of the ¿7-nAChR deficient mouse. We will begin by determining, during normal development, the level of expression and localization of key elements of the nAChR pathway including the high affinity choline transporter, choline acetyltransferase, and the nAChR subunits. We will study EC from normal retinal vessels using laser capture microdissection and real time RT-PCR, in situ hybridization and immunohistochemistry. We will carefully assess vascular and neuronal development in the retina of the ¿7-nAChR deficient mouse. Finally, we will determine if pharmacological antagonism of nAChRs in the eye (comparing non-selective versus ¿7-nAChR selective antagonists) will adversely effect normal neuronal or vascular development. 2. Determine if excessive activation of this pathway contributes to retinal neovascularization in a murine model of ROP, using pharmacological and genetic knockdown of EC nAChRs. Using the methods described above, we will determine if retinal neovascularization is associated with increased retinal expression of any components of the nAChR pathway. We will determine if administration of the non-selective (mecamylamine) or ¿7-preferential (methyllycaconitine) nAChR antagonists suppress retinal neovascularization. The effect of nAChR antagonists on retinal neuronal function will be assessed by ERGs. ROP will be induced in ¿7- nAChR knockout mice and littermate controls to determine if signaling through ¿7- nAChRs contributes to retinal neovascularization. We will perform biochemical studies to assess the relationship between plasma and retinal levels of ACh, and correlate these levels to changes in retinal levels of vascular endothelial growth factor (VEGF), retinal vascularity and permeability.