Immune basis for hippocampal cholinerginc deficits in pyridostigmine-treated rats

描述（由申请人提供）： 从海湾战争（GW）返回后，退伍军人表现出一系列症状-指定的海湾战争疾病（GWI）-不能与单一疾病相关。GW退伍军人还显示出心理症状和精神障碍的发生率增加，沿着下丘脑-垂体-肾上腺（HPA）轴功能和神经解剖学变化的改变。这些症状的确切原因尚不清楚。 乙酰胆碱酯酶（AChE）抑制剂溴化吡啶斯的明（PB）被用来预防神经毒剂的有害影响，在GW。当结合士兵所经历的操作压力时，这种PB暴露被认为是GWI晚期认知功能障碍的原因之一。其他研究确定PB是GW退伍军人免疫细胞功能受损的一个致病因素，这可能导致GWI中观察到的记忆缺陷。由于迷走神经胆碱能传入和传出控制调节炎症的反射回路，我们建议调查的假设，即压力和PB暴露的综合影响导致免疫功能改变，然后导致修改胆碱能反应的关键脑区，导致认知缺陷。使用临床前模型相结合的反复心理应激和PB暴露，我们将测试我们的总体假设，即GWI的神经认知缺陷与PB和反复应激对免疫功能的综合影响有关，从而改变海马中乙酰胆碱的功能。将在以下目的中检验该假设：“目的1将检查PB +重复应激的组合是否诱导HPA轴功能障碍、增加细胞因子水平、降低向海马的胆碱能投射的活性并调节迷走神经延髓中心。目的2将检查海马突触重组、神经元和小胶质细胞树突结构和神经元变性，这些分析将为在RRS + PB大鼠中观察到的认知缺陷提供功能解剖学基础。目标3将直接评估PB和应激暴露对海马体中乙酰胆碱释放的综合影响。在体内微透析将被用来检查基础和行为诱导的海马乙酰胆碱水平的变化，在一个依赖于海马的任务的性能，并在暴露于急性应激源。目标4将通过在血浆、脾脏和淋巴结以及从海马分离的小胶质细胞中进行免疫学分析，更直接地评估在早期和延迟时间点暴露于PB +/-重复应激后，应激和PB如何影响免疫功能。这些研究的成功完成将证明PB +重复应激暴露的组合会引起外周介导的促炎细胞因子/趋化因子的变化，这些细胞因子/趋化因子在机制上导致海马胆碱能活性缺陷，从而为行为缺陷提供神经化学和解剖学基础暴露于PB和应激事件。最重要的是，成功完成拟议的研究将确定位点的治疗干预，可以迅速实施的治疗GWI在我们的退伍军人。

DESCRIPTION (provided by applicant): Following return from the Gulf War (GW), Veterans have exhibited of a constellation of symptoms - designated Gulf War Illness (GWI) - that cannot be associated with a single disease. GW Veterans also show increased rates of developing psychological symptoms and psychiatric disorders, along with alterations in hypothalamic-pituitary-adrenal (HPA) axis function and neuroanatomical changes. The precise cause for these symptoms remains unknown. The acetylcholinesterase (AChE) inhibitor pyridostigmine bromide (PB) was used as prophylaxis against the deleterious effects of nerve agents during the GW. When combined with the operational stress experienced by soldiers, this PB exposure has been proposed as one of the causes of the late cognitive dysfunction in GWI. Other studies determined that PB is a causative factor in the development of impaired immune cell function in GW Veterans, which may contribute to the memory deficits observed in GWI. Since vagal cholinergic afferents and efferents control a reflex circuit that regulates inflammation, we propose to investigate the hypothesis that the combined effects of stress and PB exposure result in altered immune function, which then leads to modifications in cholinergic responses in key brain areas that lead to cognitive deficits. Using a preclinical model of combined repeated psychological stress and PB exposure, we will test our overarching hypothesis that the neurocognitive deficits in GWI are related to combined effects of PB and repeated stress on immune function that alters acetylcholine function in hippocampus. This hypothesis will be tested in the following Aims: "Aim 1 will examine whether the combination of PB + repeated stress induces HPA axis dysfunction, increases cytokine levels, reduces the activity of cholinergic projections to the hippocampus and modulates vagal medullary centers." "Aim 2 will examine hippocampal synaptic re-organization, neuronal and microglia dendritic architecture and neuronal degeneration, analyses which would provide a functional anatomical basis for cognitive deficits observed in RRS + PB rats." "Aim 3 will directly assess the combined effects of PB and stress exposure on acetylcholine release in the hippocampus. In vivo microdialysis will be used to examine basal and behaviorally-induced changes in hippocampal acetylcholine levels during the performance of a hippocampal-dependent task and during an exposure to an acute stressor." "Aim 4 will more directly assess how stress and PB affect immune function via immunological analyses performed in plasma, spleen, and lymph nodes, as well as microglia isolated from the hippocampus, after exposure to PB +/- repeated stress at early and delayed time points. Successful completion of these studies will demonstrate that the combination of PB + repeated stress exposure elicits peripherally-mediated changes in pro-inflammatory cytokines/chemokines that are mechanistically responsible for deficits in hippocampal cholinergic activity, thereby providing a neurochemical and anatomical basis for behavioral deficits following exposure to PB and stressful events. Most importantly, successful completion of the proposed studies will identify loci for therapeutic intervention that can be quickly implemented for the treatment of GWI in our Veterans.