TNF-alpha in cell death & neuroprotection in glaucoma

TNF-α在细胞死亡中的作用

• 批准号: 7100119
• 负责人: Gulgun TEZEL
• 金额: $ 25.12万
• 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/7100119
• 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(申请人提供)：虽然青光眼是世界范围内导致失明的主要原因，但导致青光眼视网膜神经节细胞死亡的确切致病机制和有效的神经保护策略都尚不清楚。肿瘤坏死因子-α(TNF-α)是青光眼视网膜神经节细胞死亡的介质。体外实验表明，在青光眼高眼压和缺血等应激源作用下，激活的胶质细胞分泌的肿瘤坏死因子-α可诱导视网膜神经节细胞的凋亡性死亡。青光眼患者视网膜神经节细胞及其轴突中肿瘤坏死因子-α的表达增加，死亡受体-1表达上调。也有令人信服的体内证据从高压青光眼的大鼠模型中获得，这表明了肿瘤坏死因子-a在这些眼睛中的致病作用。(1)与青光眼相似，高眼压后大鼠眼内肿瘤坏死因子-α及其受体-1的表达增加；(2)肿瘤坏死因子-α信号参与了青光眼细胞死亡过程中的细胞死亡，表现为视网膜caspase-8的激活，这是肿瘤坏死因子受体家族细胞死亡途径中的一个近端效应蛋白；(3)抗肿瘤坏死因子-α治疗对高眼压大鼠眼具有神经保护作用。其他体内证据来自使用缺乏肿瘤坏死因子受体-1的小鼠的视神经挤压损伤模型的研究。虽然这不是青光眼的模型，但这些研究的结果提供了证据，表明肿瘤坏死因子-α信号与视神经损伤后视网膜神经节细胞的死亡有关。因此，目前在本申请中提出的证据共同为进一步评估肿瘤坏死因子-α介导的青光眼细胞死亡提供了强有力的理论基础。这些实验旨在利用体外和体内模型，确定视网膜神经节细胞和神经胶质细胞中肿瘤坏死因子-α介导的细胞死亡和神经保护的确切机制。利用原代共培养技术，我们将分别研究外源性肿瘤坏死因子-α对视网膜神经节细胞和神经胶质细胞半胱氨酸天冬氨酸氨基转移酶和线粒体事件的激活，以及对天然保护机制和选定的激酶通路的激活。利用大鼠青光眼模型，将在活体内研究内源性肿瘤坏死因子-α的诱导与细胞死亡之间的关系。此外，特定的抗肿瘤坏死因子-α治疗提供神经保护的有效性将在这个体内模型中根据功能和解剖学结果进一步确定。在这项申请中提出的研究中，对细胞死亡和保护的精确机制的更好的理解应该有助于有效地操纵青光眼视网膜神经节细胞的生存。