Cholinergic Modulation of Inflammatory CNS Cytokines

描述(申请人提供)：我们正在研究神经元-神经胶质细胞相互作用的机制，在此背景下，促炎症细胞因子和尼古丁胆碱能神经递质系统如何相互作用，以确定神经炎性环境中神经元对兴奋性毒素的敏感性，这通常存在于神经疾病中。总体假设是：中枢神经系统细胞预先暴露于胆碱能激动剂尼古丁，改变了由肿瘤坏死因子α启动的信号传递，改变了神经元对兴奋性毒素的易感性，并改变了神经炎症过程中的中枢神经系统反应。这一假说源于几个关键的结果，包括：1.培养的大脑皮层神经元可以抵抗NMDA毒性的TNFpha或尼古丁的攻击，然而，当这两种药物同时存在于混合神经元和神经胶质细胞的培养中时，TNFα和尼古丁诱导的神经保护被取消；2.这些药物在丰富的神经元培养中没有拮抗作用，这表明需要其他非神经元细胞类型；3.在丰富的神经元培养中加入单核巨噬细胞/小胶质细胞(MP/MG)可以恢复尼古丁和TNFa之间的拮抗作用。4.培养的MP/MG细胞表达nAChRs，它们在功能上对尼古丁的存在有反应；5.尼古丁的加入改变了TNFpha启动的caspase8激活的动力学，caspase8是TNFpha信号的重要细胞内介质。我们将在特定目标1中确定尼古丁/肿瘤坏死因子α拮抗NMDA的神经保护作用是否需要包括神经元和MP/MG在内的中枢神经系统细胞之间的特异性细胞间相互作用，在特定目标2中，除了nAChRalpha7外，神经元表达的神经元尼古丁受体是否参与了与尼古丁/肿瘤坏死因子α拮抗神经保护相关的机制(S)，以及在特定目标3中，尼古丁预适应是否通过改变半胱氨酸酶/蛋白酶的激活和/或功能来改变其对TNFα的反应。这些研究对于理解尼古丁持续存在对中枢神经系统炎症的正常调节的影响具有直接和新颖的意义，这可能决定对许多毒素的易感性，并影响正常和病理反应。

DESCRIPTION (provided by applicant): We are examining mechanisms of neuronal-glial interactions within the context of how a proinflammatory cytokines and the nicotinic cholinergic neurotransmitter systems interact to determine neuronal susceptibility to excitotoxins in a neuroinflammatory environment, as is often present in neurological disease. The Overall Hypothesis is: Pre-exposure of CNS cells to the cholinergic agonist, nicotine, modifies signaling initiated by TNF alpha and alters neuronal vulnerability to excitotoxins and the CNS response during neuro-inflammatory processes. This hypothesis stems from several key results that include: 1. Cultured cortical neurons are protected against an NMDA-toxic challenge by TNFalpha or nicotine, however, TNF alpha and nicotine induced neuroprotection is abolished when the agents are present together cultures of mixed neurons and glia, 2. These agents are not antagonistic in enriched neuronal cultures suggesting that other non-neuronal cell types are required, 3. The addition of mononuclear phagocytes/microglial cells (MP/MG) to enriched neuronal cultures restores antagonism between nicotine and TNFalpha. 4. MP/MG in culture express nAChRs, and they respond functionally to the presence of nicotine, and 5. Nicotine administration alters the kinetics of TNFalpha-initiated caspase 8 activation, an important intracellular mediator of TNFalpha-signaling. We will determine in Specific Aim 1 if nicotine/TNFalpha antagonism of neuroprotection to NMDA requires specific cell-cell interactions between cells of the CNS including neurons and MP/MG, In Specific Aim 2 if neuronal nicotinic receptors, in addition to nAChRalpha7, and expressed by cell types other than neurons, participate in mechanism(s) related to nicotine/TNFalpha antagonism of neuroprotection and in Specific Aim 3 if nicotine preconditioning of CNS cells alters their response to TNFalpha through modifying caspase/protease activation and/or function. These studies have direct and novel implications toward understanding the consequences of sustained nicotine presence on the normal regulation of neuro-inflammation in the CNS, which may determine susceptibility to many toxins and influence normal and pathological responses.