The role of TREM2 in Alzheimer's disease pathogenesis

TREM2在阿尔茨海默病发病机制中的作用

• 批准号: 8936326
• 负责人: Taylor Reagan Jay
• 金额: $ 2.92万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8936326
• 关键词: Affect; Alzheimer' s Disease; Alzheimer' s disease model; Alzheimer' s disease risk; Amyloid Protein AA; Amyloid beta-Protein; Anti-Inflammatory Agents; Anti-inflammatory; Area; Binding; Biological Assay; Biological Response Modifiers; Brain; Cell Line; Cellular Stress; Chaperonin 60; Coupled; Data; Deposition; Development; Disease; Equilibrium; Fellowship; Flow Cytometry; Health; Heat shock proteins; Hippocampus (Brain); Human; Immune; Immune response; Immunohistochemistry; Immunoprecipitation; Impaired cognition; Impairment; In Vitro; Inflammation; Inflammatory; Inflammatory Response; Late Onset Alzheimer Disease; Lead; Ligands; Location; MAPT gene; Memory; Microglia; Microspheres; Mus; Mutation; Myeloid Cells; Neurons; Pathogenesis; Pathology; Patients; Performance; Phagocytosis; Phenotype; Play; Prevalence; Production; Proteins; Published Comment; Radial; Risk; Role; Signal Transduction; Slice; Specificity; Staining method; Stains; Stress; Surface; Testing; Therapeutic Intervention; Time; Transgenic Mice; Up-Regulation; Water; Western Blotting; amyloid pathology; arm; behavior test; cognitive change; conditioned fear; cytokine; early onset; extracellular; high risk; immune function; loss of function mutation; mouse model; nervous system disorder; neuroinflammation; neuron loss; novel; object recognition; prevent; receptor; response; spatiotemporal; theories; therapeutic development; uptake

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is a devastating neurological disease that affects millions of people across the globe. The pathology of this disease is characterized by the accumulation of the beta amyloid (Aβ) protein into extracellular plaques and the intracellular accumulation of the microtubule associated protein tau. Inflammation has also been shown to play an important role in pathology, a theory supported by the recent discovery of mutations in the immune regulating protein TREM2 in AD patients. While it is known that TREM2 is important in suppressing inflammation and promoting phagocytosis, its exact role in AD is unclear. Our preliminary data suggests that TREM2 binds to Hsp60, a pro-inflammatory immune regulator that is increased in response to cellular stress. Because of their opposing actions on inflammation, we predict that Hsp60 biases TREM2 to interact with downstream components that block its anti-inflammatory function. We also show that Hsp60 levels are increased in neurons containing elevated levels of intraneuronal Aβ in a mouse model of AD. We predict that Hsp60 downregulates TREM2 activity in areas where cellular stress is high, thereby promoting inflammation at the specific time and in the specific location where cellular stress is occurring. Without TREM2, we predict that the balance in inflammation will tip toward proinflammatory responses and that inflammation will no longer be localized to areas of cellular stress. In order to determine the role of TREM2 in AD, we will first examine the role of Hsp60-TREM2 signaling in vitro. Using microglia cultured from WT or transgenic mice lacking TREM2, we will be able to determine the TREM2-dependent effects of Hsp60 treatment on cytokine production using qRT-PCR and phagocytosis, using a fluorescent microsphere uptake assay coupled with flow cytometry. We also aim to determine the changes in TREM2 and Hsp60 expression and localization during the progression of pathology in the 5xFAD AD mouse model using immunohistochemistry, Western blotting, and flow cytometry. We expect that expression of Hsp60 will increase in neurons early in pathology, and that TREM2 will be upregulated globally to re-set the balance of inflammation. Finally, we will look at the effect of the constitutive loss of TREM2 on pathology in AD mice. We expect that these mice will have increased production of pro- inflammatory cytokines and decreased phagocytic capacity. Consequently, when pathology in these mice is determined using ThioS staining for plaque number, and NeuN staining to assay neuronal loss, TREM2-/- 5xFAD mice will show earlier and more severe changes. We also predict earlier cognitive decline in AD mice which lack TREM2 in tests such as novel object recognition, radial arm water maze and fear conditioning. Through these studies, we hope to gain a better understanding of the role of TREM2 in AD and provide a novel avenue for the development of therapeutic interventions for AD patients.

描述（由适用提供）：阿尔茨海默氏病（AD）是一种毁灭性的神经系统疾病，影响了全球数百万人。该疾病的病理特征是β-淀粉样蛋白（Aβ）蛋白在细胞外斑块中的积累和微管相关蛋白TAU的细胞内积累。炎症还被证明在病理学中起重要作用，这一理论是由最近在AD患者中发现免疫调节蛋白TREM2突变支持的理论。尽管众所周知，TREM2在抑制注射和促进吞噬作用方面很重要，但其在AD中的确切作用尚不清楚。我们的初步数据表明，TREM2与HSP60结合，HSP60是一种促炎性免疫调节剂，随着细胞应激的响应而增加。由于它们对炎症的反对作用，我们预测HSP60会偏向TREM2与阻断其抗炎功能的下游成分相互作用。我们还表明，在AD小鼠模型中含有含有升高水平的神经元Aβ水平的神经元中HSP60水平升高。我们预测，HSP60在细胞应激较高的地区下调了TREM2活性，从而在特定时间和发生细胞应激的特定位置促进感染。没有TREM2，我们预测炎症的平衡将朝着促炎反应倾斜，并且炎症将不再定位于细胞应激区域。为了确定TREM2在AD中的作用，我们将首先检查体外Hsp60-Trem2信号传导的作用。使用从WT或缺乏Trem2的转基因小鼠培养的小胶质细胞，我们将能够使用荧光微粒摄取测定法与流式细胞仪相结合，确定使用QRT-PCR和吞噬作用，使用QRT-PCR和吞噬作用来确定Hsp60处理对细胞因子产生的Trem2依赖性作用。我们还旨在通过免疫组织化学，蛋白质印迹和流式细胞术来确定5xFAD AD小鼠模型中病理学过程中TREM2和HSP60表达和定位的变化。我们预计，HSP60早期神经元的表达将在病理学早期增加，并且TREM2将在全球范围内上调以重新设置炎症的平衡。最后，我们将研究构成型损失TREM2对AD小鼠病理学的影响。我们预计这些小鼠将增加促炎性细胞因子的产生并增加吞噬能力。因此，当这些小鼠的病理使用菌斑数量的蒂奥斯染色确定，而Neun染色以断言神经元丧失时，TREM2 - / - 5XFAD小鼠将显示早期和更严重的变化。我们还预测了AD小鼠的早期认知下降，这些认知能力在新的对象识别，径向臂迷宫和恐惧条件等测试中缺乏TREM2。通过这些研究，我们希望更好地了解TREM2在AD中的作用，并为AD患者开发治疗干预措施提供新的途径。