Dissecting the differential role of TREM2 and TYROBP in microglial homeostasis, activation, and disease

剖析 TREM2 和 TYROBP 在小胶质细胞稳态、激活和疾病中的不同作用

• 批准号: 10640102
• 负责人: Gabriela Farias Quipildor
• 金额: $ 7.59万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10640102
• 关键词: Alzheimer' s Disease; Alzheimer' s disease pathology; Amyloid beta-Protein; Amyloidosis; Anti-Inflammatory Agents; Apolipoprotein E; Binding Proteins; Biological Assay; Brain; Cause of Death; Cell Survival; Cells; Complex; Coupling; Cytoplasmic Tail; Data; Dementia; Disease; Disease associated microglia; Evaluation; Event; Exhibits; Exposure to; Gene Expression Regulation; Global Change; Goals; Homeostasis; Human; ITAM; Immune; Immunologic Surveillance; Individual; Inflammation; Inflammatory; Inflammatory Response; Knock-in; Knockout Mice; Late Onset Alzheimer Disease; Ligand Binding; Lipids; Lipopolysaccharides; Mass Spectrum Analysis; Memory Loss; Microglia; Missense Mutation; Mitogen-Activated Protein Kinases; Modeling; Molecular; Molecular Profiling; Morphology; Mutation; Natural regeneration; Nerve Degeneration; Neurodegenerative Disorders; Neurons; PIK3CG gene; Pathogenesis; Pathway interactions; Peptides; Phagocytes; Phagocytosis; Phase; Phenotype; Phosphopeptides; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphoserine; Phosphotyrosine; Physiological; Point Mutation; Proliferating; Proline; Protein Isoforms; Protein Kinase; Protein Phosphatase 2A Regulatory Subunit PR53; Protein phosphatase; Proteins; Proto-Oncogene Proteins c-akt; Receptor Protein-Tyrosine Kinases; Research; Rest; Risk; Role; SYK gene; Senile Plaques; Signal Pathway; Signal Transduction; Signaling Protein; Stimulus; Synaptic plasticity; TREM2 gene; TYROBP gene; Testing; Threonine; United States; Up-Regulation; Variant; abeta oligomer; aged; chemokine; cognitive skill; cytokine; effective therapy; extracellular; glial activation; immunoregulation; inhibitor; insight; loss of function; migration; neuroprotection; neurotoxicity; normal aging; pathogen; pharmacologic; phosphatase inhibitor; phosphoproteomics; protein aggregation; recruit; repaired; response; stoichiometry; synaptic pruning; tau aggregation; therapeutic target

PROJECT SUMMARY/ABSTRACT The Alzheimer’s Association describes Alzheimer’s disease (AD) as “the most common type of dementia”, a term that generally describes the loss of memory and some forms of cognitive skills that interfere with everyday activities. AD is one of the top three causes of death in aged individuals in the United States. It was first described by Alois Alzheimer in 1906 as an accumulation of extracellular amyloid plaques and intracellular neurofibrillary tau tangles; yet, more than a century later, there is still no effective treatment or cure to the disease. Although an abundance of research has focused on understanding AD, there are still many unknowns to the mechanisms of disease pathogenesis. Microglia, the primary immune cell in the brain, have multiple activation phenotypes that are involved in broad and complex functions in the brain, including in neurotoxicity and release of inflammatory cytokines, in repair and regeneration, in immune regulation, in neuroprotection and release of anti-inflammatory cytokines, in cell survival/proliferation/migration, and in phagocytosis. TREM2 and TYROBP are known to form a complex in microglia that can lead to complex intracellular signaling networks, and these proteins have recently emerged as important regulators of the transition between resting (homeostatic) microglia and its activation states. Recent findings from our group and others have shown a TYROBP-dependent and TREM2-independent molecular signature that exhibits involvement in the early transition step from homeostatic microglia to disease-associated microglia (DAM). Interestingly, the sequential step of DAM activation is TREM2-dependent. However, the underlying mechanisms of how TREM2 or TYROBP regulate these downstream cellular phenotypes are largely unknown. In this proposal, we aim to systematically test whether, and to what extent, AD-relevant stimuli, such as amyloid beta (A) oligomers or physiological Apolipoprotein E 3 or 4 isoforms are able to activate microglia, in the absence of TYROBP or TREM2 or in the presence of the AD-associated Trem2 R47H knockin mutation. Here, we will utilize a thorough approach to investigate not only signal transduction and various cellular activation pathways, but also we will use state-of-the-art mass spectrometry-based phosphoproteomics to unbiasedly examine global changes in phosphopeptides, in order to specifically elucidate differences in microglial homeostasis and activation states in our models. The overall goal of the study is to understand the differential roles of TREM2 and TYROBP in the mechanisms underlying microglial activation in the context of disease-like stimuli, and to ultimately identify potential therapeutic targets that specifically focus on microglia activation phenotypes, and that could contribute to the delay or treatment of AD pathology.

项目总结/摘要 阿尔茨海默氏症协会将阿尔茨海默氏症（AD）描述为"最常见的类型， 痴呆症”，这个术语通常描述记忆丧失和某些形式的认知技能的干扰 与日常活动。AD是美国老年人死亡的三大原因之一。它 Alois Alzheimer于1906年首次描述为细胞外淀粉样斑块的积累， 细胞内神经元tau蛋白缠结;然而，世纪之后，仍然没有有效的治疗或治愈方法 对疾病的影响尽管大量的研究集中在了解AD上，但仍然有许多 疾病发病机制的未知数。 小胶质细胞是大脑中的主要免疫细胞，具有多种激活表型，参与了 脑中广泛而复杂的功能，包括神经毒性和炎性细胞因子的释放， 修复和再生，免疫调节，神经保护和抗炎细胞因子的释放， 细胞存活/增殖/迁移和吞噬作用。已知TREM2和TYROBP形成复合物， 小胶质细胞，可以导致复杂的细胞内信号网络，这些蛋白质最近出现 作为休息（稳态）小胶质细胞和其激活状态之间的过渡的重要调节器。最近 我们小组和其他人的研究结果表明，TYROBP依赖性和TREM2独立性的分子 参与从稳态小胶质细胞到疾病相关的早期过渡步骤的信号 小胶质细胞（DAM）。有趣的是，DAM激活的顺序步骤是TREM2依赖性的。但 TREM 2或TYROBP如何调节这些下游细胞表型的潜在机制在很大程度上是 未知 在这个建议中，我们的目标是系统地测试是否，以及在多大程度上，AD相关的刺激，如 淀粉样蛋白β（A β）寡聚体或生理性载脂蛋白E β 3或β 4同种型能够激活小胶质细胞， 不存在TYROBP或TREM2或存在AD相关的Trem2 R47H敲入突变。 在这里，我们将利用一个彻底的方法来调查不仅信号转导和各种细胞活化 途径，但我们也将使用最先进的质谱为基础的磷酸蛋白质组学， 检查磷酸肽的整体变化，以具体阐明小胶质细胞中的差异， 稳态和激活状态。本研究的总体目标是了解 TREM2和TYROBP在类疾病背景下小胶质细胞活化机制中的作用 刺激，并最终确定潜在的治疗靶点，特别是集中在小胶质细胞激活 表型，并可能有助于延迟或治疗AD病理。