Abstract：
Microglia, the main resident immune cells in the central nervous system, are implicated in the pathogenesis of various neurological disorders. Much of our knowledge on microglial biology was obtained using rodent microglial cultures. To understand the role of microglia in human disease, reliable in vitro models of human microglia are necessary. Monocyte-derived microglia-like cells (MDMi) are a promising approach. This study aimed to characterize MDMi cells generated from adult human monocytes using granulocyte-macrophage colony-stimulating factor and interleukin-34. To this end, 49 independent cultures of MDMI were prepared, and various methodological and functional studies were performed. We show that with this protocol, adult human monocytes develop into microglia-like cells, a coating is unnecessary, and high cell density seeding is preferable. When compared to monocytes, MDMi upregulate the expression of many, but not all, microglial markers, indicating that, although these cells display a microglia-like phenotype, they cannot be considered bona fide human microglia. At the functional level, MDMi phagocytose α-synuclein aggregates and responds to lipopolysaccharide (LPS) by nuclear translocation of the transcription factor nuclear factor-kappaB (NFkappaB) and the upregulation of proinflammatory genes. Finally, a long-lasting silencing of the transcription factor CCAAT/enhancer protein β (C/EBPβ) was achieved by small interfering RNA, resulting in the subsequent downregulation of proinflammatory genes. This supports the hypothesis that C/EBPβ plays a key role in proinflammatory gene program activation in human microglia. Altogether, this study sheds new light on the properties of MDMi cells and supports these cells as a promising in vitro model for studying adult human microglia-like cells.
摘要：
小胶质细胞,中枢神经系统中主要的免疫细胞，与各种神经系统疾病的发病机理有关。我们对小胶质细胞生物学的大部分知识是使用啮齿动物小胶质细胞培养物获得的。了解小胶质细胞在人类疾病中的作用,可靠的人小胶质细胞体外模型是必要的。单核细胞衍生的小胶质细胞样细胞（MDMi）是一种有前途的方法。这项研究旨在表征使用粒细胞-巨噬细胞集落刺激因子和白介素-34从成人单核细胞产生的MDMi细胞。为此,制备了49个独立的MDMI培养物，并进行了各种方法和功能研究。我们证明有了这个协议，成人单核细胞发育成小胶质细胞，涂层是不必要的，和高细胞密度接种是优选的。与单核细胞相比，MDMi上调了许多表达，但不是全部,小胶质细胞标志物，表明,尽管这些细胞表现出小胶质细胞样表型，它们不能被认为是真正的人类小胶质细胞。在功能层面,MDMi吞噬α-突触核蛋白聚集并通过转录因子核因子κB（NFkappaB）的核易位和促炎基因的上调对脂多糖（LPS）作出反应。最后,通过小干扰RNA实现了转录因子CCAAT/增强子蛋白β（C/EBPβ）的持久沉默，导致随后的促炎基因下调。这支持以下假设：C/EBPβ在人类小胶质细胞的促炎基因程序激活中起关键作用。总之,这项研究揭示了MDMi细胞的特性，并支持这些细胞作为研究成人小胶质细胞样细胞的有前途的体外模型。
