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.

项目概要/摘要 阿尔茨海默病协会将阿尔茨海默病 (AD) 描述为“最常见的类型” 痴呆症”，这个术语通常描述记忆力丧失和某些形式的认知技能的丧失 与日常活动。 AD 是美国老年人的三大死因之一。它 1906 年，阿洛伊斯·阿尔茨海默 (Alois Albert) 首次将其描述为细胞外淀粉样斑块的积累， 细胞内神经原纤维tau蛋白缠结；然而，一个多世纪过去了，仍然没有有效的治疗或治愈方法 对疾病。尽管大量研究都集中在理解 AD 上，但仍有许多研究 疾病发病机制尚不清楚。 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 大脑中广泛而复杂的功能，包括神经毒性和炎症细胞因子的释放， 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/迁移以及吞噬作用。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 作为静息（稳态）小胶质细胞与其激活状态之间转变的重要调节因子。最近的 我们小组和其他人的研究结果表明，TYROBP 依赖性且 TREM2 独立的分子 表明参与从稳态小胶质细胞到疾病相关细胞的早期过渡步骤的特征 小胶质细胞（DAM）。有趣的是，DAM 激活的顺序步骤是 TREM2 依赖性的。然而， TREM2 或 TYROBP 如何调节这些下游细胞表型的潜在机制很大程度上是 未知。 在本提案中，我们的目标是系统地测试 AD 相关刺激是否以及在多大程度上，例如 β 淀粉样蛋白 (A) 寡聚物或生理载脂蛋白 E 3 或 4 亚型能够激活小胶质细胞， TYROBP 或 TREM2 缺失或 AD 相关 Trem2 R47H 敲入突变存在。 在这里，我们将利用彻底的方法不仅研究信号转导和各种细胞激活 途径，而且我们还将使用最先进的基于质谱的磷酸蛋白质组学来公正地 检查磷酸肽的整体变化，以具体阐明小胶质细胞的差异 我们模型中的稳态和激活状态。该研究的总体目标是了解差异 TREM2 和 TYROBP 在疾病样背景下小胶质细胞激活机制中的作用 刺激，并最终确定专门针对小胶质细胞激活的潜在治疗靶点 表型，这可能有助于延迟或治疗 AD 病理。