Department of Molecular Cell Biology and Immunology, VU University Medical Center, Van der Boechhorststraat 7, BT Amsterdam, 1081, The Netherlands.
J Neuroinflammation. 2013 Mar 4;10:35. doi: 10.1186/1742-2094-10-35.
Macrophages play a dual role in multiple sclerosis (MS) pathology. They can exert neuroprotective and growth promoting effects but also contribute to tissue damage by production of inflammatory mediators. The effector function of macrophages is determined by the way they are activated. Stimulation of monocyte-derived macrophages in vitro with interferon-γ and lipopolysaccharide results in classically activated (CA/M1) macrophages, and activation with interleukin 4 induces alternatively activated (AA/M2) macrophages.
For this study, the expression of a panel of typical M1 and M2 markers on human monocyte derived M1 and M2 macrophages was analyzed using flow cytometry. This revealed that CD40 and mannose receptor (MR) were the most distinctive markers for human M1 and M2 macrophages, respectively. Using a panel of M1 and M2 markers we next examined the activation status of macrophages/microglia in MS lesions, normal appearing white matter and healthy control samples.
Our data show that M1 markers, including CD40, CD86, CD64 and CD32 were abundantly expressed by microglia in normal appearing white matter and by activated microglia and macrophages throughout active demyelinating MS lesions. M2 markers, such as MR and CD163 were expressed by myelin-laden macrophages in active lesions and perivascular macrophages. Double staining with anti-CD40 and anti-MR revealed that approximately 70% of the CD40-positive macrophages in MS lesions also expressed MR, indicating that the majority of infiltrating macrophages and activated microglial cells display an intermediate activation status.
Our findings show that, although macrophages in active MS lesions predominantly display M1 characteristics, a major subset of macrophages have an intermediate activation status.
巨噬细胞在多发性硬化症（MS）的发病机制中起双重作用。它们可以发挥神经保护和促进生长的作用，但也可以通过产生炎症介质来导致组织损伤。巨噬细胞的效应功能取决于它们的激活方式。体外用干扰素-γ和脂多糖刺激单核细胞衍生的巨噬细胞可导致经典激活（CA/M1）的巨噬细胞，而用白细胞介素 4 激活则可诱导替代激活（AA/M2）的巨噬细胞。
在这项研究中，使用流式细胞术分析了人单核细胞衍生的 M1 和 M2 巨噬细胞中一组典型的 M1 和 M2 标志物的表达。这表明 CD40 和甘露糖受体（MR）分别是人类 M1 和 M2 巨噬细胞最独特的标志物。使用一组 M1 和 M2 标志物，我们接下来检查了 MS 病变、正常表现的白质和健康对照样本中巨噬细胞/小胶质细胞的激活状态。
我们的数据表明，M1 标志物，包括 CD40、CD86、CD64 和 CD32，在正常表现的白质和活跃脱髓鞘 MS 病变中的活化小胶质细胞和巨噬细胞中大量表达。M2 标志物，如 MR 和 CD163，在活跃病变中的髓鞘载巨噬细胞和血管周巨噬细胞中表达。用抗 CD40 和抗 MR 进行双重染色显示，MS 病变中约 70%的 CD40 阳性巨噬细胞也表达 MR，这表明浸润的巨噬细胞和活化的小胶质细胞的大部分显示出中间激活状态。
我们的研究结果表明，尽管活跃 MS 病变中的巨噬细胞主要表现出 M1 特征，但巨噬细胞的一个主要亚群具有中间激活状态。
