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（由申请人提供）：阿尔茨海默病（AD）是一种毁灭性的神经系统疾病，影响地球仪数百万人。这种疾病的病理学特征是β淀粉样蛋白（Aβ）在细胞外斑块中的积累和微管相关蛋白tau在细胞内的积累。炎症也被证明在病理学中起重要作用，这一理论得到了最近发现的AD患者免疫调节蛋白TREM 2突变的支持。虽然已知TREM 2在抑制炎症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，TREM 2与Hsp 60结合，Hsp 60是一种促炎免疫调节剂，在细胞应激反应中增加。由于它们对炎症的相反作用，我们预测Hsp 60使TREM 2偏向于与下游组分相互作用，从而阻断其抗炎功能。我们还发现，在AD小鼠模型中，神经元内Aβ水平升高的神经元中Hsp 60水平增加。我们预测Hsp 60在细胞应激高的区域下调TREM 2活性，从而在细胞应激发生的特定时间和特定位置促进炎症。如果没有TREM 2，我们预测炎症的平衡将倾向于促炎反应，炎症将不再局限于细胞应激区域。 为了确定TREM 2在AD中的作用，我们将首先在体外检查Hsp 60-TREM 2信号传导的作用。使用从WT或缺乏TREM 2的转基因小鼠培养的小胶质细胞，我们将能够使用qRT-PCR和吞噬作用，使用与流式细胞术偶联的荧光微球摄取测定来确定Hsp 60处理对细胞因子产生的TREM 2依赖性作用。我们还旨在使用免疫组织化学、蛋白质印迹和流式细胞术确定5xFAD AD小鼠模型中病理进展期间TREM 2和Hsp 60表达和定位的变化。我们预计，Hsp 60的表达将在病理学早期的神经元中增加，并且TREM 2将在整体上上调以重新设定炎症的平衡。最后，我们将研究TREM 2的组成性缺失对AD小鼠病理学的影响。我们预计这些小鼠将增加促炎细胞因子的产生，并降低吞噬能力。因此，当使用用于斑块数量的ThioS染色和用于测定神经元损失的NeuN染色来确定这些小鼠中的病理学时，TREM 2-/-5xFAD小鼠将显示更早和更严重的变化。我们还预测了缺乏TREM 2的AD小鼠在诸如新物体识别、径向臂水迷宫和恐惧条件反射等测试中的早期认知下降。通过这些研究，我们希望能够更好地了解TREM 2在AD中的作用，并为AD患者的治疗干预提供新的途径。