Molecular Analysis of Retinal Ganglion Cell Death

描述（由申请人提供）：青光眼是一种以视网膜神经节细胞死亡导致视野丧失为特征的疾病。虽然眼压升高仍然是青光眼最明确的危险因素，但越来越清楚的是，许多其他因素也可导致神经节细胞损失。药物或手术调节眼压可以稳定许多患者，但对一些患者仍有进行性视力丧失。因此，迫切需要制定新的合理策略来减缓或预防青光眼中发生的神经元丢失。有大量证据表明，眼睛，像中枢神经系统的其他区域一样，含有内源性神经营养/神经保护因子，其功能是限制细胞损伤。这一建议的基本前提是，这些神经保护机制可以用来预防许多与青光眼等疾病相关的细胞死亡。这一建议的重点是一种神经保护分子CNTF，这种因子已经被证明在包括视网膜在内的许多中枢神经系统区域具有强大的神经保护作用，并且是减缓神经节细胞损失进展的主要候选因子。在我们的初步数据中，我们提供了证据，证明CNTF支持纯化的大鼠RGCs在低密度培养中存活，其下游效应物STAT3可防止缺血-再灌注损伤中的RGCs变性。我们现在提出了一系列的实验来测试是否可以通过CNTF阻止rgc在谷氨酸中毒水平下死亡。在第一个目标中，我们将定义CNTF用于发挥其保护作用的途径。其次，我们将研究Muller胶质细胞是否能够通过分泌额外的神经保护因子或一系列其他反应对CNTF作出反应，并为rgc提供协同保护。最后，我们将测试CNTF激活的保护途径是否通过激活线粒体解偶联蛋白导致线粒体产生活性氧的减少。

DESCRIPTION (provided by applicant): Glaucoma is a disease characterized by visual field loss as a result of the death of retinal ganglion cells. Although increased intraocular pressure remains the most clearly defined risk factor for glaucoma, it is becoming clear that a wide range of other factors can also lead to ganglion cell loss. Pharmacological or surgical regulation of intraocular pressure can stabilize many patients but for some there is still a progressive loss of vision. Thus, there is an urgent need to develop new rational strategies to slow or prevent neuronal loss occurring in glaucoma. There is abundant evidence that the eye, like other regions of the CNS, contains endogenous neurotrophic/neuroprotective factors that function to limit cell injury. It is the basic premise of this proposal that these neuroprotective mechanisms can be exploited to prevent much of the cell death associated with diseases such as glaucoma. This proposal focuses on one neuroprotective molecule, CNTF, a factor that has already been shown to have potent neuroprotective effects in a number of CNS regions including the retina and is a leading candidate for slowing the progression of ganglion cell loss. In our preliminary data we present evidence that CNTF supports the survival of purified rat RGCs in low density cultures and that its downstream effector STAT3 prevents RGCs from degenerating in ischemia- reperfusion injury. We now propose a series of experiments to test if RGCs can be prevented from dying in the presence of toxic levels of glutamate by CNTF. In a first aim we will define the pathways used by CNTF to exert its protective action. Second, we will examine whether Muller glia can respond to CNTF and provide synergistic protection to RGCs by the secretion of additional neuroprotective factors or a range of other responses. Finally we will test whether the protective pathways activated by CNTF lead to a reduction in reactive oxygen species generation by mitochondria through the activation of mitochondrial uncoupling proteins. PUBLIC HEALTH RELEVANCE: Glaucoma is a blinding disease that affects over 65 million people worldwide. There is still not a good understanding of the basic biochemical mechanisms which cause the death of retinal cells and subsequent loss of vision. This research will identify some of these biochemical pathways. The results of this research will lead to the identification of target molecules for which new therapeutic drugs can be designed.