Disease-Modifying Effects of Filgastrim in a Mouse Model of AD

摘要/摘要 粒细胞集落刺激因子(G-CSF)是一种多途径的造血生长因子 通常用于血液学/肿瘤学，但有关其对脑部疾病的益处的报道如下 出现在文学作品中。阿尔茨海默病(AD)小鼠模型的初步研究 实验室表明，它既有促进认知的作用，也有改善疾病的作用。其作用机制 对这些深刻影响的责任尚不清楚，G-CSF作为一种治疗剂的发展 对阿尔茨海默病患者进行临床前研究。 目的：拟议的研究旨在阐明细胞和分子机制，通过 哪种G-CSF降低淀粉样蛋白沉积/水平，刺激海马神经再生和修复 阿尔茨海默病小鼠模型的突触功能活动。目标1：假设增加了贩运 骨髓来源的细胞从血液到脑和/或小胶质细胞和吞噬细胞活性增加是 导致β-淀粉样蛋白(A-？)沉积减少的原因将在嵌合的TG AD小鼠中进行测试 其中骨髓来源的细胞表达绿色荧光蛋白(GFP)。目标2：测试 假设G-CSF的前认知效应是通过对神经前体的直接作用来实现的 细胞和神经元，G-CSF促进神经发生和/或促进恢复的程度 海马顶突触的功能和结构将通过神经解剖学和 电生理技术。目标3：在细胞内的水平上，机制研究将阐明 由G-CSF触发的新信号通路涉及切换到选择性剪接变异体 蛋白激酶C(PKC-delta2)刺激海马神经发生并抑制多聚 Tau的磷酸化，两者都被认为是改善海马突触的基础 功能。方法：细胞和分子生物学技术、免疫组织化学、海马区 将采用脑片电生理学和行为分析。嵌合Tg AD小鼠移植 将生成绿色荧光蛋白表达(GFP+)的骨髓细胞以确定 外周来源的小胶质细胞和其他骨髓来源的细胞对 淀粉样蛋白减少和/或神经再生。 迄今为止的研究结果：给予认知受损的TG AD小鼠(APP+PS1)G-CSF可逆转 认知能力受损，海马区A？沉积显著减少 内嗅皮层。G-CSF治疗的TGAD小鼠也显示出总的小胶质细胞明显增加和 海马区CA1和CA3区突触素免疫染色面积增加。其他内容 G-CSF给Tg AD小鼠的初步结果包括刺激 海马片的神经发生和电生理功能的改善。 临床意义：G-CSF常规且安全地用于治疗中性粒细胞减少症和刺激 健康骨髓捐献者的造血干细胞生成。增强认知能力和 G-CSF对阿尔茨海默病小鼠模型的潜在疾病修饰作用 逆转或阻止AD患者痴呆进展的临床试验。 与退伍军人事务部相关：AD是一种不治之症，与年龄相关，患病率为5% 在美国有100万人。随着退伍军人人口的老龄化，AD的患病率将会增加，导致 对退伍军人管理局医疗保健系统的巨大需求。从人道主义和社会经济两方面 观点，迫切需要能够延缓或逆转疾病的药物。 进行性阿尔茨海默病。

Abstract/Summary Filgastrim (granulocyte colony stimulating factor or G-CSF) is a multi-modal hematopoietic growth factor used routinely in the hematology/oncology setting but reports of its benefits for brain diseases are appearing in the literature. Preliminary studies in a mouse model of Alzheimer's disease (AD) in our laboratory suggests it has both pro-cognitive and disease-modifying effects. The mechanisms responsible for these profound effects are not clear and development of G-CSF as a therapeutic agent for patients with AD warrants pre-clinical research. Objectives: The proposed studies are designed to elucidate the cellular and molecular mechanisms by which G-CSF reduces amyloid deposition/levels, stimulates hippocampal neurogenesis and restores synaptic functional activity in a mouse model of AD. Aim 1: The hypothesis that enhanced trafficking of bone-marrow derived cells from blood to brain and/or increased microglial and phagocytic activity is responsible for the decrease in beta-amyloid (A-¿) deposition will be tested in a chimeric tg AD mouse in which bone marrow derived cells express green fluorescent protein (GFP). Aim 2: To test the hypothesis that the pro-cognitive effects of G-CSF are mediated by direct actions on neural progenitor cells and neurons, the extent to which G-CSF promotes neurogenesis and/or promotes recovery of hippocamapal synaptic function and structure will be tested with neuroanatomical and electrophysiological techniques. Aim 3: At an intracellular level, mechanistic studies will elucidate a novel signaling pathway triggered by G-CSF that involves switching to an alternatively spliced variant of protein kinase C (PKC-delta2) that stimulates hippocampal neurogenesis and inhibits poly- phosphorylation of Tau, both which are postulated to underlie improved hippocampal synaptic function. Methods: Cellular and molecular biology techniques, immunohistochemistry, hippocampal slice electrophysiology and behavioral analysis will be employed. Chimeric tg AD mice engrafted with green fluorescent protein expressing (GFP+) bone marrow cells will be generated to determine the extent to which peripherally derived microglia and other bone marrow-derived cells contribute to amyloid reduction and/or neurogenesis. Findings to date: Administration of G-CSF to cognitively-impaired tg AD mice (APP+PS1) reversed the impaired cognitive performance and significantly decreased A¿ deposition in hippocampus and entorhinal cortex. G-CSF-treated tg AD mice also revealed a significant increase in total microgliosis and increased areas of synaptophysin immunostaining in hippocamal CA1 and CA3 regions. Additional preliminary results obtained from G-CSF administration to tg AD mice include stimulation of hippocampal neurogenesis and improvement of electrophysiological function in hippocampal slices. Clinical relevance: G-CSF is routinely and safely used to treat neutropenia and to stimulate hematopoietic stem cell generation in healthy bone marrow donors. The cognitive-enhancing and potential disease-modifying effects of G-CSF in a mouse model of AD provides a strong impetus for clinical trials to reverse or forestall progression of dementia in AD patients. Relevance to VA Mission: AD is an incurable, age-dependent dementing disease with a prevalence of 5 million in the US. As the veteran population ages, the prevalence of AD will increase, resulting in overwhelming demands on the VA health care system. From both humanitarian and socio-economic perspectives, there is an urgent need for disease-modifying medications that delay or reverse the progressive dementia of AD.