Table_2_GW5074 Increases Microglial Phagocytic Activities: Potential Therapeutic Direction for Alzheimer’s Disease.XLSX

Microglia, the resident immune cells of the central nervous system (CNS), are responsible for maintaining homeostasis in the brain by clearing debris and are suggested to be inefficient in Alzheimer’s Disease (AD), a progressive neurodegenerative disorder for which there is no disease-modifying drug. Besides pathological approaches, unbiased evidence from genome-wide association studies (GWAS) and gene network analysis implicate genes expressed in microglia that reduce phagocytic ability as susceptibility genes for AD. Thus, a central feature toward AD therapy is to increase the microglial phagocytic activities while maintaining synaptic integrity. Here, we developed a robust unbiased high content screening assay to identify potential therapeutics which can reduce the amyloid-beta (Aβ1–42) load by increasing microglial uptake ability. Our screen identified the small-molecule GW5074, an inhibitor of c-RAF, a serine/threonine kinase, which significantly increased the Aβ1–42 clearance activities in human monocyte-derived microglia-like (MDMi) cells, a microglia culture model that recapitulates many genetic and phenotypic aspects of human microglia. Notably, GW5074 was previously reported to be neuroprotective for cerebellar granule cells and cortical neurons. We found that GW5074 significantly increased the expression of key AD-associated microglial molecules known to modulate phagocytosis: TYROBP, SIRPβ1, and TREM2. Our results demonstrated that GW5074 is a potential therapeutic for AD, by targeting microglia.

微胶质细胞，中枢神经系统（CNS）的固有免疫细胞，通过清除代谢废物维持大脑的稳态平衡，并被认为是阿尔茨海默病（AD）——一种尚无疾病修饰药物治疗的进行性神经退行性疾病的病理机制之一。除了病理学方法之外，来自全基因组关联研究（GWAS）和基因网络分析的无偏证据表明，在微胶质细胞中表达的降低吞噬能力的基因被认为是AD的易感基因。因此，针对AD治疗的关键特征在于提高微胶质细胞的吞噬活性，同时保持突触完整性。在本研究中，我们开发了一种稳健的无偏高内涵筛选方法，以识别能够通过增加微胶质细胞摄取能力来减少淀粉样蛋白-β（Aβ1–42）负荷的潜在治疗药物。我们的筛选发现了一种小分子化合物GW5074，它是c-RAF（丝氨酸/苏氨酸激酶）的抑制剂，显著提高了人单核细胞来源的微胶质细胞样（MDMi）细胞——一种能够重现人类微胶质细胞许多遗传和表型特征的细胞培养模型——的Aβ1–42清除活性。值得注意的是，GW5074先前已被报道对脑干颗粒细胞和皮层神经元具有神经保护作用。我们发现GW5074显著增加了已知可调节吞噬作用的AD相关微胶质细胞关键分子的表达：TYROBP、SIRPβ1和TREM2。我们的研究结果证明了GW5074通过靶向微胶质细胞，成为AD的潜在治疗药物。