OKHSC COBRE: OXIDATIVE STRESS AND INFLAMMATION IN DIABETIC RETINOPATHY

这个子项目是许多利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 糖尿病视网膜病变（DR）是美国失明的主要原因。DR的早期病理特征包括视网膜血管细胞功能障碍、血-视网膜屏障（blood-retinal barrier，BRB）破坏、血管渗漏和神经变性。尽管其发病机制尚不清楚，但最近的研究表明，氧化应激和炎症在DR的发病机制中起着关键作用。 内源性血管生成抑制剂。越来越多的证据表明PEDF在DR中的有益作用，即抑制视网膜新生血管形成和减少血管渗漏;然而，其机制尚未完全阐明。我们最近的新研究表明，PEDF是一种有效的抗炎因子， 抑制DR中的血管渗漏。此外，PEDF减少糖尿病诱导的超氧化物（O2.-）以及视网膜周细胞和糖尿病视网膜中过氧亚硝酸盐（ONOO-）的产生。基于这些重要发现，我们推测PEDF通过减少氧化应激改善糖尿病视网膜并发症 和炎症。在目标1中，我们将集中于通过确定PEDF对O2的影响来确定PEDF作为内源性抗氧化因子的活性。在培养的视网膜内皮细胞和视网膜神经元中ONOO-生成、促炎因子表达、内皮紧密连接和神经元变性。我们还将确定视网膜中PEDF的过度表达或下调是否会改善或增加视网膜中PEDF的表达。 通过比较糖尿病和正常年龄匹配的PEDF转基因小鼠、PEDF缺陷小鼠和野生型小鼠的这些参数，研究DR中的氧化应激和炎症。在目标2中，我们将探索PEDF抑制O2的机制。ONOO-编队。我们假设PEDF抑制糖尿病诱导的O2。通过抗氧化酶的上调和/或线粒体功能的保护而产生。如果我们的 假设被证明，我们将继续探索信号通路，以探索PEDF如何调节抗氧化酶和/或PEDF如何保护线粒体功能。如果结果表明其他机制也可能有助于PEDF的抗氧化作用，我们将确定替代PEDF是否和如何 通过抑制主要的氧化还原酶，即NADPH氧化酶、黄嘌呤氧化酶和eNOS，减少超氧化物的产生。该项目的成功不仅将确定DR的新致病机制，还将有助于开发使用内源性血管生成抑制剂的新疗法。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Diabetic retinopathy (DR) is a leading cause of blindness in the US. The early pathologic hallmarks of DR nclude retinal vascular cellular dysfunction, blood-retinal barrier (BRB) breakdown, vascular leakage and neural degeneration. Although the mechanisms largely unknown, recent studies suggest that oxidative stress and inflammation plays a critical role in the pathogenesis of DR. Pigment epithelium-derived factor (PEDF) is an endogenous angiogenic inhibitor. Accumulating evidence suggests beneficial effects of PEDF in DR, i.e. nhibition of retinal neovascularization and reduction of vascular leakage; however, the mechanisms are not fully elucidated. Our recent novel studies demonstrated that PEDF is a potent anti-inflammatory factor and inhibits vascular leakage in DR. Moreover, PEDF reduces diabetes-induced superoxide (O2.-) and peroxynitrite (ONOO-) production in retinal pericytes and in diabetic retina. Based on these important findings, we hypothesize that PEDF ameliorates diabetic retinal complications by reducing oxidative stress and inflammation. In Aim 1, we will focus on establishing the activity of PEDF as an endogenous anti-oxidant factor by determining the effects of PEDF on O2.-/ONOO- generation, pro-inflammatory factor expression, endothelial tight junction and neuron degeneration in cultured retinal endothelial cells and retinal neurons. We will also determine if over-expressing or down-regulating PEDF in the retina will ameliorate or augment oxidative stress and inflammation in DR by comparing these parameters in diabetic and normal age-matched PEDF transgenic mice, PEDF deficient mice and wildtype mice. In Aim 2, we will explore the mechanisms by which PEDF inhibits O2.-/ONOO- formation. We hypothesize that PEDF suppresses diabetes-induced O2.- generation via up-regulation of anti-oxidant enzymes and / or protection of mitochondrial function. If our hypothesis is proved, we will pursue the signaling pathway to explore how PEDF regulates anti-oxidant enzymes and / or how PEDF protects mitochondrial function. If the results indicate that other mechanisms may also contribute to the PEDF effects on anti-oxidation, we will determine alternatively if and how PEDF reduces superoxide generation by inhibiting the major redox enzymes, i.e. NADPH oxidase, xanthine oxidase and eNOS. The success of this project will not only identify a novel pathogenic mechanism for DR, but also contribute to the development of new therapies using endogenous angiogenic inhibitors.