TNF-alpha in cell death & neuroprotection in glaucoma

TNF-α在细胞死亡中的作用

• 批准号: 6616471
• 负责人: Gulgun TEZEL
• 金额: $ 30.56万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6616471
• 关键词: BCL2 gene /protein; apoptosis; cysteine endopeptidases; cytokine receptors; enzyme activity; glaucoma; glia; intraocular pressure; laboratory rat; mitochondria; mixed tissue /cell culture; neuroprotectants; nuclear factor kappa beta; protein kinase; retinal ganglion; tumor necrosis factor alpha

DESCRIPTION (provided by applicant): Although glaucoma is a leading cause of worldwide blindness, neither the precise pathogenic mechanisms, which lead to retinal ganglion cell death in glaucoma, nor effective strategies for neuroprotection are known. Tumor necrosis factor-alpha (TNF-alpha) has recently been identified to be a mediator of retinal ganglion cell death in glaucoma. In vitro evidence demonstrates that TNF-alpha secreted by activated glial cells in response to glaucomatous stressors, such as elevated intraocular pressure and ischemia, can induce apoptotic death of retinal ganglion cells. Glial production of TNF-alpha is increased, and TNF receptor-1, a death receptor, is upregulated in retinal ganglion cells and their axons in glaucomatous human eyes. There is also compelling in vivo evidence obtained from a rat model of high-pressure glaucoma, which demonstrates the pathogenic role of TNF-a in these eyes. (1) Similar to glaucomatous human eyes, the expression of TNF-alpha and TNF receptor-1 are increased in rat eyes following intraocular pressure elevation; (2) TNF-alpha signaling is involved in cell death in these eyes, as evidenced by the activation of retinal caspase-8 -a proximal effector protein in the TNF receptor family cell death pathway; (3) anti-TNF-alpha treatment in ocular hypertensive rat eyes can provide neuroprotection. Additional in vivo evidence comes from studies using the optic nerve crush injury model in mice deficient for TNF receptor-1. Although this is not a model for glaucoma, findings of these studies provide evidence that TNF-alpha signaling is involved in the death of retinal ganglion cells following optic nerve injury. Thus, current evidence presented in this application collectively provides a strong rationale for further evaluation of the TNF-alpha mediated cell death in glaucoma. The proposed experiments aim to identify the precise mechanisms of TNF-alpha-mediated cell death and neuroprotection in retinal ganglion cells and glial cells, using in vitro and in vivo models. Using primary co-cultures, activation of caspases and mitochondrial events, and activation of native protection mechanisms and selected kinase pathways will be separately studied in retinal ganglion cells and glial cells exposed to exogenous TNF-alpha. Using a rat glaucoma model, the relationship between the induction of endogenous TNF-alpha and cell death will be studied, in vivo. In addition, the effectiveness of a specific anti-TNF-alpha treatment to provide neuroprotection will be further determined in this in vivo model using both the functional and the anatomical outcomes. An improved understanding of the precise mechanisms of cell death and protection in studies proposed in this application should facilitate efforts to effectively manipulate the survival of retinal ganglion cells in glaucoma.

描述（由申请人提供）：尽管青光眼是全球失明的主要原因，但既不是导致青光眼中视网膜神经节细胞死亡的精确致病机制，也不知道有效的神经保护策略。肿瘤坏死因子-Alpha（TNF-Alpha）最近被确定为青光眼中视网膜神经节细胞死亡的介体。体外证据表明，激活的神经胶质细胞分泌的TNF-α响应青光眼应激源（例如升高的眼压和缺血）会诱导视网膜神经节细胞的凋亡死亡。 TNF-α的神经胶质产生增加，而死亡受体TNF受体-1在视网膜神经节细胞及其轴突中上调，在青光眼的人眼中。从高压青光眼的大鼠模型中获得的体内证据也令人信服，这证明了TNF-A在这些眼中的致病作用。 （1）与青光眼的人眼类似，在眼内压升高后，大鼠眼中TNF-Alpha和TNF受体1的表达增加了。 （2）TNF-Alpha信号在这些眼睛中与细胞死亡有关，这是由视网膜caspase-8 -a -a近端效应蛋白激活在TNF受体家族细胞死亡途径中的激活所证明的； （3）眼部高血压大鼠眼睛中的抗TNF-Alpha治疗可以提供神经保护作用。在缺乏TNF受体1的小鼠中，使用视神经挤压损伤模型的研究提出了其他体内证据。尽管这不是青光眼的模型，但这些研究的发现提供了证据表明TNF-Alpha信号传导与视神经损伤后视网膜神经节细胞死亡有关。因此，本应用中提出的当前证据共同提供了强大的理由，以进一步评估青光眼中TNF-Alpha介导的细胞死亡。提出的实验旨在使用体外和体内模型来确定视网膜神经节细胞和神经胶质细胞中TNF-Alpha介导的细胞死亡和神经保护的精确机制。使用初级共培养，将在视网膜神经节细胞和暴露于外源性TNF-Alpha的视网膜神经节细胞和神经胶质细胞中分别研究胱天蛋白酶和线粒体事件的激活以及天然保护机制和所选激酶途径的激活。使用大鼠青光眼模型，将研究内源性TNF-α与细胞死亡的诱导之间的关系。此外，使用功能和解剖结局，将在该体内模型中进一步确定特定抗TNF-Alpha治疗提供神经保护作用的有效性。在本应用中提出的研究中，对细胞死亡和保护的确切机制的确切机制有了改进的理解，应促进有效地操纵视网膜神经节细胞在青光眼中的存活率的努力。