Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
J Neuroinflammation. 2013 Jul 17;10:85. doi: 10.1186/1742-2094-10-85.
Microglia are the primary immune cells of the brain whose phenotype largely depends on their surrounding micro-environment. Microglia respond to a multitude of soluble molecules produced by a variety of brain cells. Macrophage colony-stimulating factor (M-CSF) is a cytokine found in the brain whose receptor is expressed by microglia. Previous studies suggest a critical role for M-CSF in brain development and normal functioning as well as in several disease processes involving neuroinflammation.
Using biopsy tissue from patients with intractable temporal epilepsy and autopsy tissue, we cultured primary adult human microglia to investigate their response to M-CSF. Mixed glial cultures were treated with 25 ng/ml M-CSF for 96 hours. Proliferation and phagocytosis assays, and high through-put immunocytochemistry, microscopy and image analysis were performed to investigate microglial phenotype and function.
We found that the phenotype of primary adult human microglia was markedly changed following exposure to M-CSF. A greater number of microglia were present in the M-CSF- treated cultures as the percentage of proliferating (BrdU and Ki67-positive) microglia was greatly increased. A number of changes in protein expression occurred following M-CSF treatment, including increased transcription factors PU.1 and C/EBPβ, increased DAP12 adaptor protein, increased M-CSF receptor (CSF-1R) and IGF-1 receptor, and reduced HLA-DP, DQ, DR antigen presentation protein. Furthermore, a distinct morphological change was observed with elongation of microglial processes. These changes in phenotype were accompanied by a functional increase in phagocytosis of Aβ1-42 peptide.
We show here that the cytokine M-CSF dramatically influences the phenotype of adult human microglia. These results pave the way for future investigation of M-CSF-related targets for human therapeutic benefit.
小胶质细胞是大脑的主要免疫细胞，其表型在很大程度上取决于其周围的微环境。小胶质细胞对多种由各种脑细胞产生的可溶性分子作出反应。巨噬细胞集落刺激因子（M-CSF）是一种存在于大脑中的细胞因子，其受体由小胶质细胞表达。先前的研究表明，M-CSF 在大脑发育和正常功能中以及在涉及神经炎症的几种疾病过程中都起着关键作用。
我们使用来自难治性颞叶癫痫患者的活检组织和尸检组织，培养原代成人人类小胶质细胞，以研究它们对 M-CSF 的反应。用 25ng/ml 的 M-CSF 处理混合神经胶质细胞 96 小时。进行增殖和吞噬作用测定，以及高通量免疫细胞化学、显微镜和图像分析，以研究小胶质细胞的表型和功能。
我们发现，暴露于 M-CSF 后，原代成人人类小胶质细胞的表型发生了显著变化。在 M-CSF 处理的培养物中存在更多的小胶质细胞，因为增殖（BrdU 和 Ki67 阳性）小胶质细胞的比例大大增加。M-CSF 处理后发生了许多蛋白质表达的变化，包括转录因子 PU.1 和 C/EBPβ 的增加、DAP12 衔接蛋白的增加、M-CSF 受体（CSF-1R）和 IGF-1 受体的增加，以及 HLA-DP、DQ、DR 抗原呈递蛋白的减少。此外，还观察到小胶质细胞突起的伸长，表现出明显的形态变化。这些表型变化伴随着 Aβ1-42 肽吞噬作用的功能增加。
我们在这里表明，细胞因子 M-CSF 显著影响成人人类小胶质细胞的表型。这些结果为未来研究 M-CSF 相关靶点以造福人类治疗铺平了道路。
