Blood-Retinal Barrier Changes in Retinopathy

该项目旨在通过靶向治疗糖尿病视网膜病变， 尿激酶/尿激酶受体系统（uPA/uPAR）。我们以前的工作表明，糖尿病/高 葡萄糖诱导的视网膜血管损伤是由氧化应激诱导的增加介导的 在VEGF的表达，这导致破坏血视网膜屏障，由于激活的血管内皮细胞， uPA/uPAR系统。我们的初步数据将这些事件与糖尿病在降低血糖方面的作用联系起来。 抗血管生成神经营养生长因子色素上皮衍生因子的表达 （PEDF）。已知PEDF阻断VEGF的血管生成和渗透性诱导功能。 糖尿病视网膜病变和以血视网膜屏障破坏为特征的疾病的研究 和视网膜新生血管的研究表明，视网膜VEGF的增加与 PEDF下降。氧化应激通过增加基质的形成减少PEDF 金属蛋白酶2和9（MMP 2，MMP 9），其降解和降解PEDF。我们的初步 数据表明糖尿病诱导的uPAR增加与MMP 9和MMP-9的增加有关， PEDF下降。此外，uPAR基因的缺失阻止MMP 9释放，保留了MMP 9的活性。 PEDF和保护血视网膜屏障。我们也有数据显示糖尿病引起的 神经元/神经胶质细胞死亡与PEDF减少相关。根据这些数据，我们 假设糖尿病和高葡萄糖诱导血-视网膜屏障破坏， 通过引起uPA/uPAR系统的激活和减少PEDF而导致神经胶质细胞死亡。这 一个假设将通过细胞和分子生物学相结合的实验来检验 具体目的的方法来测试以下假设：1。糖尿病需要uPAR- 诱导的血视网膜屏障的破坏和神经/神经胶质细胞死亡，通过激活 uPA/uPAR。2.抑制uPA蛋白水解活性将阻断糖尿病诱导的视网膜病变的减少。 PEDF水平，并防止血液视网膜屏障和神经/神经胶质细胞死亡的破坏。 3. uPA/uPAR系统的激活导致细胞旁通透性通过uPA- 介导的蛋白水解。4. PEDF抑制VEGF或高糖诱导的细胞旁 通过阻断uPA/uPAR表达途径来降低细胞通透性。 这些研究将为开发针对神经和神经系统的治疗方法奠定基础。 糖尿病视网膜病变是导致工作中失明的主要原因， 今天美国的成年人。

This project seeks to develop new therapies for diabetic retinopathy by targeting the urokinase/urokinase receptor system (uPA/uPAR). Our previous work has shown that diabetes/high glucose-induced injury of the retinal vasculature is mediated by oxidative stress-induced increases in VEGF expression, which causes breakdown of the blood-retinal barrier due to activation of the uPA/uPAR system. Our preliminary data link these events to diabetes' action in decreasing the expression of the anti-angiogenic, neuro-trophic growth factor pigment epithelial derived factor (PEDF). PEDF is known to block the angiogenic and permeability-inducing functions of VEGF. Studies of diabetic retinopathy and diseases characterized by breakdown of the blood-retinal barrier and retinal neovascularization have shown that increases in retinal VEGF are correlated with decreases in PEDF. Oxidative stress reduces PEDF by increasing the formation of matrix metalloproteinases 2 and 9 (MMP2, MMP9), which degrade and inactivate PEDF. Our preliminary data suggest that diabetes-induced increases in uPAR are associated with increases in MMP9 and decreases in PEDF. Moreover deletion of the uPAR gene prevents MMP9 release, preserves PEDF and protects the blood-retinal barrier. We also have data showing that diabetes-induced neuronal/glial cell death is correlated with decreases in PEDF. Based on these data, we hypothesize that diabetes and high glucose induce breakdown of the blood-retinal barrier and neuro-glial cell death by causing activation of the uPA/uPAR system and decreasing PEDF. This hypothesis will be tested by experiments using a combination of cell and molecular biology approaches in specific aims to test the following hypotheses: 1. uPAR is required for diabetes- induced breakdown of the blood-retinal barrier and neual/glial cell death via activation of uPA/uPAR. 2. Inhibiting uPA proteolytic activity will block diabetes-induced decreases in retinal PEDF levels and prevent breakdown of the blood-retinal barrier and neural/glial cell death. 3. Activation of the uPA/uPAR system causes increases in paracellular permeability viauPA- mediated proteolysis. 4. PEDF inhibits VEGF or high glucose-induced increases in paracellular permeability by blocking the uPA/uPAR expression pathway. These studies will set the stage for developing therapies for targeting both neural and vascular pathology and preventing diabetic retinopathy, the leading cause of blindness in working age adults in the US today.