TANK 结合激酶 1 (TBK1) 是一种重要的激酶,参与先天免疫和肿瘤发展。巨噬细胞集落刺激因子 (M-CSF) 调节巨噬细胞在多形性胶质母细胞瘤微环境中向免疫抑制性 M2 表型的分化和功能。TBK1 在巨噬细胞中的作用,特别是在响应 M-CSF 刺激的调节巨噬细胞极化中的作用,仍不清楚。在这里,我们发现 TBK1 在人神经胶质瘤浸润的骨髓细胞中高表达,磷酸化的 TBK1 在 M-CSF 刺激的巨噬细胞中高表达,但在粒细胞-巨噬细胞 CSF 诱导的巨噬细胞中不高表达(粒细胞-巨噬细胞-CSF 参与 M1 巨噬细胞的极化)。髓系细胞中 TBK1 的条件性缺失诱导 M-CSF 刺激的骨髓来源的巨噬细胞表现出促炎性 M1 样表型,CD86、白细胞介素-1β 和肿瘤坏死因子-α 的蛋白表达增加,以及精氨酸酶 1 的表达降低。从机制上讲,amlexanox 或 GSK8612 的 TBK1 缺失或抑制降低了转录因子干扰素调节因子 (IRF)4 的表达,并增加了 M-CSF 刺激的巨噬细胞中 IRF5 的激活水平,导致具有高度促炎因子的 M1 样特征。IRF5 缺失逆转了 TBK1 抑制对 M-CSF 介导的巨噬细胞极化的影响。我们的研究结果表明,TBK1 部分通过 IRF5/IRF4 轴响应 M-CSF 刺激,有助于巨噬细胞极化的调节。
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TBK1 is involved in M‐CSF‐induced macrophage polarization through mediating the IRF5/IRF4 axis
TANK binding kinase 1 (TBK1) is an important kinase that is involved in innate immunity and tumor development. Macrophage colony‐stimulating factor (M‐CSF) regulates the differentiation and function of macrophages towards the immunosuppressive M2 phenotype in the glioblastoma multiforme microenvironment. The role of TBK1 in macrophages, especially in regulating macrophage polarization in response to M‐CSF stimulation, remains unclear. Here, we found high TBK1 expression in human glioma‐infiltrating myeloid cells and that phosphorylated TBK1 was highly expressed in M‐CSF‐stimulated macrophages but not in granulocyte‐macrophage CSF‐induced macrophages (granulocyte‐macrophage‐CSF is involved in the polarization of M1 macrophages). Conditional deletion of TBK1 in myeloid cells induced M‐CSF‐stimulated bone marrow‐derived macrophages to exhibit a proinflammatory M1‐like phenotype with increased protein expression of CD86, interleukin‐1β and tumor necrosis factor‐α, as well as decreased expression of arginase 1. Mechanistically, TBK1 deletion or inhibition by amlexanox or GSK8612 reduced the expression of the transcription factor interferon‐regulatory factor (IRF)4 and increased the level of IRF5 activation in macrophages stimulated with M‐CSF, leading to an M1‐like profile with highly proinflammatory factors. IRF5 deletion reversed the effect of TBK1 inhibition on M‐CSF‐mediated macrophage polarization. Our findings suggest that TBK1 contributes to the regulation of macrophage polarization in response to M‐CSF stimulation partly through the IRF5/IRF4 axis.