ENDOTHELIN EFFECTS ON RETINAL CELLS AND BLOOD FLOW

描述（改编自申请人摘要）： 建议是了解ET及其受体在调节 视网膜血流动力学在正常和糖尿病状态下在体内和 培养的视网膜血管细胞。 自从第一份报告显示 视网膜周细胞中ETA受体的存在及其调控 胰岛素、ET-1和ET-3的ET-1表达已经显示出具有许多 在视网膜血管细胞中的作用。 调查结果显示， 证实了ET-1通过ETA受体是一个主要的调节因子， 正常稳态和高氧时视网膜血管张力， 糖尿病视网膜病变的早期症状 增加的血管收缩 在这些状态中观察到的是由于ET-1的过度表达或 内皮素转化酶（ECE）在其加工过程中的增加， 视网膜。 最近，申请人已经表明胰岛素可以降低ET-1 周细胞和平滑肌细胞中的基因表达， 解释胰岛素的体内血管舒张作用。 在信号 在信号转导水平，ET-1和血管紧张素可影响磷脂酶C （PLC）-蛋白激酶C（PKC）激活和酪氨酸激酶级联 涉及周细胞和平滑肌细胞中的MAP激酶。 研究者 最近发现血管紧张素和ET-1也可以激活G蛋白 相关的磷脂酰肌醇3-激酶（PI 3-激酶），从而鉴定 一种全新的ET-1信号转导途径 最后，发现， 高血糖可减弱ET-1对PLC激活的影响 平滑肌细胞和系膜细胞也是如此。 研究者 目的：（1）研究ET-1的表达和加工， 视网膜血管细胞受胰岛素、氧张力、血管紧张素 和高血糖;（2）识别各种信号传导途径 ET-1在视网膜周细胞和平滑肌细胞中使用， G蛋白相关PI 3-激酶的激活和 这些生物作用的途径，如钙流，NO的产生， DNA合成;（3）测定ET-1的表达及作用 和ET-3及其受体对正常视网膜血流动力学的影响， 糖尿病

DESCRIPTION (Adapted from applicant's abstract): The purpose of the proposal is to understand the role of ET and its receptors in modulating retinal hemodynamics in the normal and diabetic state in vivo and in cultured retinal vascular cells. Since the first report showing the existence of ETA receptors in the retinal pericytes and the regulation of ET-1 expression by insulin, ET-1 and ET-3 have been shown to have many actions in retinal vascular cells. The investigator's results have established the fact that ET-1 via ETA receptor is a major regulator of vascular tone in the retina during normal homeostasis and hyperoxia and in the early stages of diabetic retinopathy. The increased vasoconstriction observed in these states are due to either overexpression of ET-1 or increase in its processing by endothelin converting enzyme (ECE) in the retina. Recently, the applicant has shown that insulin can decrease ET-1 gene expression in pericytes and smooth muscle cells which could partially explain the in vivo vasodilatory effect of insulin. At the signal transduction level, ET-1 and angiotensin can affect phospholipase C (PLC)-protein kinase C (PKC) activation and the tyrosine kinase cascade involving MAP kinase in pericytes and smooth muscle cells. The investigator has recently found that angiotensin and ET-1 can also activate a G-protein associated phosphatidylinositol 3-kinase (PI 3-kinase), thereby identifying a whole new signal transduction pathway for ET-1. Lastly, the finding that hyperglycemia can blunt ET-1's effect on PLC activation has been confirmed by smooth muscle cells and mesangial cells as well. The investigator proposes: (1) to characterize the expression and processing of ET-1 in retinal vascular cells as regulated by insulin, oxygen tension, angiotensin and hyperglycemia; (2) to identify the various signal transduction pathways used by ET-1 in retinal pericytes and in smooth muscle cells specifically on the activation of G-protein-associated PI 3-kinase and the association of these pathways to biological actions such as calcium flux, NO production and DNA synthesis; and (3) to determine the expression and the effect of ET-1 and ET-3 and their receptors in vivo on normal retinal hemodynamics and in diabetes.