Soluble TREM2 regulation of microglial function in Alzheimer disease

可溶性 TREM2 对阿尔茨海默病小胶质细胞功能的调节

• 批准号: 10432584
• 负责人: MARCO COLONNA
• 金额: $ 43.06万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-05 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10432584
• 关键词: Affect; Age; Alzheimer' s Disease; American; Amyloid beta-Protein; Apoptotic; Binding; Binding Proteins; Brain; CRISPR/Cas technology; Candidate Disease Gene; Cause of Death; Cells; Chimeric Proteins; Dementia; Deposition; Development; Disease; Engineering; Functional disorder; Genetic; Human; Immunologic Receptors; Integral Membrane Protein; Intrathecal Injections; Knockout Mice; Lipoproteins; Membrane; Microglia; Modeling; Mus; Pathology; Phagocytosis; Phospholipids; Prevention; Proteins; Regulation; Risk; Risk Factors; Senile Plaques; Signal Transduction; Slice; TREM2 gene; TYROBP gene; Time; United States; Variant; beta amyloid pathology; brain cell; cognitive function; cost estimate; efficacy evaluation; experimental study; genetic variant; genome wide association study; improved; mouse model; novel strategies; novel therapeutics; protein aggregation; receptor; receptor binding; therapy development; tool; whole genome

PROJECT SUMMARY Alzheimer's Disease (AD) is the 6th leading cause of death in the United States and more than 5.8 million Americans suffer from this disease. This year the estimated cost of AD and other dementias is $305 billion, and could rise to $1.1 trillion by 2050. The cause of AD remains elusive and is likely multifactorial. The greatest risk factors are known to be age, genetics, and inheritance. Genome-wide association studies have shown that variants of TREM2 are associated with two to four times the risk of developing AD. TREM2 is an innate immune receptor expressed in microglia that has been shown to interact with phospholipids, apoptotic cells, lipoproteins, and oligomeric forms of amyloid-β (Aβ). This protein has been shown to be required for microglial proliferation, survival, and phagocytosis of Aβ. TREM2 is a transmembrane protein with no intracellular signaling domains; signal transduction requires binding to DAP12. Upon microglial activation and clustering, TREM2 is cleaved from the membrane generating soluble TREM2 (sTREM2). Since both membrane-bound TREM2 and sTREM2 coexist during different stages of AD, it has been difficult to differentiate the extent of which each form independently contributes to disease pathology. It was recently shown that after intrathecal administration, sTREM2 binds to microglia, transmitting intracellular signals, promoting survival, improving cognitive function, and mitigating Aβ pathology; it has been postulated that sTREM2 acts through a putative yet unknown receptor. In this proposal we will utilize a CRISPR/Cas9 whole genome screen to identify the receptor that binds sTREM2 on microglia and promotes signal transduction. Identified candidate genes will be validated in human microglial cells and knockout mouse models will be generated to further explore the importance of each in the development of AD and its pathophysiology. These models will serve as tools that will permit us to identify how sTREM2 modulates microglia independently from membrane-bound TREM2. Such discovery will serve as the basis for novel therapeutics aimed at modulation of the sTREM2 receptor. sTREM2 has also been shown to bind Aβ plaques. We will exploit this observation and develop sTREM2-fraction crystallizable(sTREM2-Fc) fusion proteins that bind Aβ plaques and promote activation of microglia and phagocytosis. The sTREM2-Fc fusion proteins will be validated using slices of brains from 5XFAD mice that accumulate A plaques typical of AD. We will also perform intrathecal injections, which will allow us to evaluate the efficacy of sTREM2-Fc in eliminating plaques and activating microglia. Taken together, these are novel approaches that may help to develop therapies that enhance clearance and prevention of amyloid-β plaque formation for the treatment of AD.

项目概要 阿尔茨海默氏病 (AD) 是美国第六大死因，超过 580 万人患有此病 今年，美国人因 AD 和其他痴呆症造成的损失估计为 3050 亿美元。 到 2050 年，这一数字可能会增加到 1.1 万亿美元。AD 的病因仍然难以捉摸，而且可能是多因素造成的。 已知的因素包括年龄、遗传学和遗传，全基因组关联研究表明。 TREM2 的变异与患 AD 的风险是先天免疫的两到四倍相关。 小胶质细胞中表达的受体已被证明与磷脂、凋亡细胞、脂蛋白相互作用， β 淀粉样蛋白 (Aβ) 的寡聚形式已被证明是小胶质细胞增殖所必需的， TREM2 是一种没有细胞内信号传导结构域的跨膜蛋白； 信号转导需要与 DAP12 结合，小胶质细胞激活和聚集后，TREM2 就会被裂解。 由于膜结合 TREM2 和 sTREM2，膜产生可溶性 TREM2 (sTREM2)。 AD 的不同阶段共存，很难区分每种形式的程度 最近表明，鞘内给药后， sTREM2 与小胶质细胞结合，传递细胞内信号，促进生存，改善认知功能， 并减轻 Aβ 病理；据推测 sTREM2 通过假定的但未知的受体发挥作用。 在本提案中，我们将利用 CRISPR/Cas9 全基因组筛选来鉴定结合 sTREM2 的受体 确定的候选基因将在人类小胶质细胞中得到验证。 将生成细胞和基因敲除小鼠模型，以进一步探索每种细胞在开发中的重要性 这些模型将作为工具帮助我们确定 sTREM2 的作用机制。 独立于膜结合的 TREM2 调节小胶质细胞，这一发现将作为研究的基础。 旨在调节 sTREM2 受体的新型疗法也被证明可以结合 Aβ。 我们将利用这一观察结果并开发 sTREM2 分数结晶 (sTREM2-Fc) 融合体。 结合 Aβ 斑块并促进小胶质细胞激活和吞噬作用的蛋白质 sTREM2-Fc 融合。 将使用 5XFAD 小鼠的大脑切片来验证蛋白质，这些小鼠积累了 AD 典型的 A 斑块。 还将进行鞘内注射，这将使我们能够评估 sTREM2-Fc 在消除 总的来说，这些都是可能有助于开发治疗方法的新方法。 增强β淀粉样蛋白斑块的清除和预防，从而治疗 AD。