COBRE: UND: TNF-ALPHA/GLUTAMATE INDUCED CELL DEATH IN ALZHEIMER'S DISEASE

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。小胶质细胞依赖性炎症对于从阿尔茨海默病（AD）到多发性硬化症和帕金森病的神经退行性疾病至关重要。因此，有毒的小胶质细胞促炎产物以及它们的神经元毒性的特定机制可能在许多病理情况下是共同的。确定这些毒素的性质以及它们的作用模式将为预防许多神经退行性疾病中的炎症变化提供分子靶点。虽然在AD脑中发现了与β-淀粉样蛋白斑块相关的丰富的反应性小胶质细胞，但它们对细胞损失的确切贡献仍然是推测性的。在体外，原纤维刺激小胶质细胞分泌神经毒性产物，表明小胶质细胞炎症直接导致AD中的细胞死亡。初步证据表明，淀粉样蛋白β原纤维刺激培养的小鼠小胶质细胞分泌兴奋性神经递质谷氨酸和促炎细胞因子TNF α。这些促炎分泌物直接诱导小鼠皮层神经元培养物的死亡，在一个氧化损伤依赖的方式，需要增加诱导型一氧化氮合酶和随后的过氧亚硝酸盐生产的神经元表达。TNF受体（p55）和NMDA受体的同时刺激导致神经元死亡，因为单独的两种因子都不足以引发细胞死亡。因此，我们将测试AD脑为TNF α和谷氨酸提供适当的小胶质细胞介导的炎症环境以协同刺激TNF α和谷氨酸受体信号传导途径并导致细胞死亡的假设。以下具体目标将解决这一假设：1）确定是否坏死或凋亡细胞死亡是由TNF α和谷氨酸受体激动剂，NMDA的神经元皮层培养物的协同刺激诱导的。2)确定神经元中无毒TNF α单独和无毒NMDA单独介导的信号应答的机制。3)确定协同TNF α + NMDA介导的信号传导串扰导致氧化损伤依赖性神经元死亡的机制。

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. Microglial-dependent inflammation is critical for neurodegenerative conditions ranging from Alzheimer¿s disease (AD) to multiple sclerosis and Parkinson¿s disease. Therefore,toxic microglial proinflammatory products as well as their specific mechanisms of neuronal toxicity are likely common to numerous pathological situations. Identifying the nature of these toxins as well as their modes of action will provide molecular targets for preventing the inflammatory changes in numerous neurodegenerative conditions. Although abundant reactive microglia are found associated with beta-amyloid plaques in AD brains, their precise contribution to cell loss remains speculative. In vitro, fibrils stimulate microglia to secrete neurotoxic products suggesting that microglial inflammation directly contributes to cell death in AD. Preliminary evidence demonstrates that amyloid beta fibrils stimulate cultured mouse microglia to secrete the excitatory neurotransmitter, glutamate, and the pro-inflammatory cytokine, TNF alpha. These proinflammatory secretions directly induce death of mouse cortical neuron cultures in an oxidative damage-dependent fashion requiring increased neuronal expression of inducible nitric oxide synthase and subsequent peroxynitrite production. Neuron death results from coincident stimulation of the TNF receptor (p55) and NMDA receptors, as neither factor, alone, is sufficient to initiate cell death. Accordingly, we will test the hypothesis that AD brains provide the appropriate microglial-mediated inflammatory environment for TNF alpha and glutamate to synergistically stimulate TNF alpha and glutamate receptor signaling pathways and cause cell death. The following specific aims will address this hypothesis: 1) Determine whether necrotic or apoptotic cell death is induced by synergistic stimulation of neuronal cortical cultures with TNF alpha and the glutamate receptor agonist, NMDA. 2) Identify the mechanisms of nontoxic TNF alpha alone and nontoxic NMDA alone-mediated signaling responses in neurons. 3) Determine the mechanisms of the synergistic TNF alpha + NMDA mediated signaling cross-talk responsible for oxidative damage-dependent neuron death.