Institute of Biomedical Sciences, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung City, 402, Taiwan (Republic of China).
Pediatric Department, Children's Hospital, Changhua Christian Hospital, No. 320, Xuguang Rd., Changhua City, Changhua County, 500, Taiwan (Republic of China).
Ann Hematol. 2020 Mar;99(3):431-441. doi: 10.1007/s00277-020-03916-8. Epub 2020 Feb 1.
Macrophages are characterized by phenotypical and functional heterogeneity. In different microenvironments, macrophages can polarize into two types: classically activated macrophages (M1) or alternatively activated macrophages (M2). M1 macrophages are a well-known bacteriostatic macrophage, and conversely, M2 macrophages may play an important role in tumor growth and tissue remodeling. M1 macrophages have been reported to have high intracellular iron stores, while M2 macrophages contain lower intracellular iron. It has been well-described that disturbances of iron homeostasis are associated with altered immune function. Thus, it is important to investigate if chronic iron overload is capable of polarizing macrophages. Human monocytic leukemia THP-1 cells were maintained in culture medium that contained 100 μM ferrous sulfate heptahydrate (FeSO) (I-THP-1) and differentiated into THP-1-derived macrophages (I-TDMs) by induction with phorbol 12-myristate 13-acetate (PMA). We characterized that I-TDMs not only enhanced the surface expression of CD163 and CD206 but also increased arginase and decreased iNOS protein expression. I-TDMs enhanced pSTAT6 expression and decreased pSTAT1 and NF-κB expressions. Furthermore, the gene expression profile of I-TDMs was comparable with M2 macrophages by performing human oligonucleotide DNA microarray analysis. Finally, functional assays demonstrated I-TDMs secreted higher levels of IL-10 but not M1 cytokines. Additionally, the conditional medium of I-TDMs had enhanced migration and increased invasion of A375 melanoma cells which was similar to the characteristics of tumor-associated macrophages. Taken together, we demonstrated that THP-1-derived macrophages polarized to a phenotype of M2-like characteristics when subjected to chronic iron overload.
巨噬细胞具有表型和功能异质性。在不同的微环境中，巨噬细胞可以极化为两种类型：经典激活的巨噬细胞（M1）或替代激活的巨噬细胞（M2）。M1 巨噬细胞是一种众所周知的抑菌巨噬细胞，相反，M2 巨噬细胞可能在肿瘤生长和组织重塑中发挥重要作用。已经报道 M1 巨噬细胞具有高细胞内铁储存，而 M2 巨噬细胞含有较低的细胞内铁。铁稳态的紊乱与免疫功能的改变有关，这已经得到了很好的描述。因此，研究慢性铁过载是否能够极化巨噬细胞是很重要的。人单核白血病 THP-1 细胞在含有 100 μM 硫酸亚铁七水合物（FeSO）的培养基中培养（I-THP-1），并通过佛波醇 12-肉豆蔻酸 13-醋酸盐（PMA）诱导分化为 THP-1 衍生的巨噬细胞（I-TDMs）。我们发现 I-TDMs 不仅增强了 CD163 和 CD206 的表面表达，还增加了精氨酸酶的表达，降低了 iNOS 的蛋白表达。I-TDMs 增强了 pSTAT6 的表达，降低了 pSTAT1 和 NF-κB 的表达。此外，通过进行人类寡核苷酸 DNA 微阵列分析，I-TDMs 的基因表达谱与 M2 巨噬细胞相似。最后，功能分析表明，I-TDMs 分泌更高水平的 IL-10，但不分泌 M1 细胞因子。此外，I-TDMs 的条件培养基增强了 A375 黑色素瘤细胞的迁移和侵袭，类似于肿瘤相关巨噬细胞的特征。总之，我们证明了 THP-1 衍生的巨噬细胞在慢性铁过载的情况下向 M2 样表型极化。
