Identification of Siglecs as molecular signatures of Disease-Associated Microglia during AD Progression

鉴定 Siglecs 作为 AD 进展过程中疾病相关小胶质细胞的分子特征

• 批准号: 10286903
• 负责人: Tong Li
• 金额: $ 45.03万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-30 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10286903
• 关键词: Age; Alzheimer' s Disease; Alzheimer' s disease model; Alzheimer' s disease pathology; Alzheimer' s disease therapy; Animal Model; Binding; Biological; Brain; Cells; Development; Disease; Disease Progression; Disease susceptibility; Family; Family member; Gene Expression; Genes; Genetic Transcription; Glycolipids; Glycoproteins; Heterogeneity; Human; Immune; Immunoglobulins; Immunosuppression; Inflammation Mediators; Integral Membrane Protein; Lead; Lectin; Ligands; Light; Link; Mediating; Microglia; Modeling; Molecular; Molecular Profiling; Mus; Neurofibrillary Tangles; Outcome; Outcome Study; Pathogenesis; Pathologic; Pathway interactions; Phagocytosis; Phenotype; Predisposition; Problem Solving; Proteins; Regulation; Regulatory Pathway; Research; Resolution; Role; Sampling; Senile Plaques; Sialic Acids; Signal Transduction; Surface; Tauopathies; Testing; Therapeutic; Wild Type Mouse; base; cerebral atrophy; genetic regulatory protein; genetic signature; genome wide association study; immunoregulation; inhibitor/antagonist; link protein; member; mouse model; neuron loss; neuronal circuitry; new therapeutic target; novel strategies; overexpression; prevent; response; sialic acid binding Ig-like lectin; single cell analysis; single-cell RNA sequencing; sugar; tau Proteins; tau aggregation; therapeutic target; transcriptome; transcriptome sequencing

PROJECT SUMMARY Microglia are implicated in the initiation and progression of Alzheimer's disease (AD), making their regulation a therapeutic target. As positive effectors, microglia phagocytose and clear toxic proteins; as negative effectors they release inflammatory mediators. Imbalance of microglial function is believed to contribute to AD progression. Among microglial regulatory proteins linked to AD susceptibility are immune inhibitory members of the Siglec family, sialic acid binding immunoglobulin-like lectins. Siglecs became a special focus of AD research when genome-wide association studies (GWAS) discovered that a Siglec family member, CD33 (Siglec-3), was associated with AD. Siglec-3 overexpression results in increased susceptibility to AD, and depletion decreases susceptibility, supporting the view that Siglec-mediated inhibition restricts microglial phagocytosis and exacerbates AD proteinopathy. As multiple inhibitory Siglecs are expressed on human (and mouse) microglia, understanding the regulation by Siglec pathways will give us opportunity to modulate the microglia function and prevent or slowdown the progression of AD. Transcriptome analyses has been widely used to revealed changes in gene expression of microglia in disease. However, since different subsets of microglia display a wide range of responses and functions, whole transcriptome analyses alone could not fully capture the context-dependent microglia variety during disease. Recent studies with single-cell analysis have provided a high-resolution view of the transcriptional landscape of microglia subtypes of the murine CNS during development and disease. Our preliminary scRNA-seq and immunocytochemical analysis demonstrated that Siglecs, especially Siglec-F, and SiglecG are associated with a specific subset of microglia that are activated at different stage of AD, which support our hypothesis that Siglec genes are specifically expressed in subsets of microglia at particular stages of AD. Here, we propose to use a combination of scRNA-seq and whole transcriptome sequencing analysis to understand the relationship between Siglecs signaling and the microglial phenotypes in AD models to elucidate the impact of microglia subtypes on AD progression. We have developed a mouse model (Tau4RΔK-AP mice) that could mimic different stages of AD development from pre-symptomatic early stage to advance stage of AD with widespread neuronal loss and brain atrophy, which is instrumental for the current proposal. In two aims, we will take advantage of Tau4RΔK-AP mice and mice expressing either only Aβ plaques (APP;PS1 mice) or only tau tangles (Tau4RΔK mice) to test the hypothesis that Siglecs regulate microglial function during AD progression in two Aims. Aim 1: To determine whether Siglecs are specifically expressed in the subset of microglia that are activated by AD pathologies at different stages of the disease. Aim 2: To determine the regulation of Siglecs as signature genes in DAMs. Successful outcome from proposed study will help define Siglecs and other microglia specific genes in AD progression, and reveal new strategies for development of new AD therapy.

项目总结 小胶质细胞与阿尔茨海默病(AD)的发生和发展有关，使它们的调节成为一种 治疗靶点。作为阳性效应细胞的小胶质细胞吞噬和透明的毒性蛋白；作为负效应蛋白 它们会释放炎症介质。小胶质细胞功能失衡被认为是导致AD进展的原因之一。 在与AD易感性相关的小胶质细胞调节蛋白中，有Siglec的免疫抑制成员 唾液酸结合免疫球蛋白样凝集素家族。当Siglecs成为AD研究的特别焦点时 全基因组关联研究发现，Siglec家族成员CD33(Siglec-3)是 与AD关联。Siglec-3过度表达导致AD易感性增加，消耗减少 易感性，支持Siglec介导的抑制限制小胶质细胞吞噬和 加重阿尔茨海默病。由于人类(和小鼠)小胶质细胞上表达多个抑制性Siglecs， 了解Siglec通路的调节将使我们有机会调节小胶质细胞的功能和 预防或减缓阿尔茨海默病的进展。转录组分析已被广泛用于揭示变化 在疾病中小胶质细胞的基因表达。然而，由于不同的小胶质细胞亚群表现出广泛的 反应和功能，单独的整个转录组分析不能完全捕捉到上下文相关的 小胶质细胞在疾病过程中的变化。最近对单细胞分析的研究提供了一个高分辨率的观点 小鼠中枢神经系统小胶质细胞亚型在发育和疾病过程中的转录图谱。我们的 初步的scRNA-seq和免疫细胞化学分析表明，Siglecs，特别是Siglec-F，和 SiglecG与在AD不同阶段被激活的小胶质细胞的特定子集相关，该子集 支持我们的假设，即Siglec基因在特定时期的小胶质细胞亚群中特异表达 公元一代的。在这里，我们建议使用scrna-seq和整个转录组测序相结合的分析来 了解Siglecs信号与AD模型小胶质细胞表型的关系以阐明 小胶质细胞亚型对AD进展的影响。我们建立了一种小鼠模型(Tau4RΔK-AP小鼠) 可以模拟AD发展的不同阶段，从症状前的早期阶段到AD的进展阶段 有广泛的神经元丢失和脑萎缩，这对目前的提议是有帮助的。在两个目标中，我们 将利用Tau4RΔK-AP小鼠和仅表达Aβ斑块的小鼠(APP；PS1小鼠)或仅表达 Tau缠结(Tau4RΔK小鼠)验证Siglecs在AD过程中调节小胶质细胞功能的假说 在两个目标中进步。目标1：确定Siglecs是否在 在疾病的不同阶段被AD病理激活的小胶质细胞。目标2：确定 Siglecs作为大坝标志性基因的调控。拟议研究的成功结果将有助于确定 Siglecs和其他小胶质细胞特异性基因在AD进展中的作用，并揭示了新的开发策略 广告疗法。

项目成果

Amyloid-beta and tau pathologies act synergistically to induce novel disease stage-specific microglia subtypes.

• DOI: 10.1186/s13024-022-00589-x
• 发表时间: 2022-12-17
• 期刊: Molecular neurodegeneration
• 影响因子: 15.1