Inhibition of mTOR suppresses IFNα production and the STING pathway in monocytes from systemic lupus erythematosus patients
Inhibition of mTOR suppresses IFNα production and the STING pathway in monocytes from systemic lupus erythematosus patients
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DOI：
10.1093/rheumatology/keaa060
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发表时间：
2020-10-01
期刊：
影响因子：
5.5
通讯作者：
Miyake, Sachiko
中科院分区：
文献类型：
--
作者：
Murayama, Goh;Chiba, Asako;Miyake, Sachiko
Objective. IFN α的增加在SLE的发病机制中是重要的。浆细胞样树突状细胞被认为是Toll样受体途径激活后IFN α的主要产生者。然而，在SLE中，哪些细胞在用环GMP-AMP合酶（cGAS）和IFN基因的刺激物（STING）刺激后产生IFN α仍是未知的。我们研究了在cGAS-STING途径刺激下骨髓细胞产生IFN α的能力。通过细胞内细胞因子染色和流式细胞术测量用cGAS-STING的刺激剂2 '3'c-GAMP刺激的来自SLE患者和健康对照的外周血单核细胞中的IFN α水平。通过流式细胞术或共聚焦显微镜检查STING表达及其与TBK 1的共定位。检测体外暴露于IFN α对IFN α产生和STING表达的影响，以及体外雷帕霉素处理对IFN α产生和STING、pTBK 1和IRF 3表达的影响。在cGAS-STING途径活化后，由单核细胞、常规树突状细胞和浆细胞样树突状细胞产生IFN α。IFN α产生单核细胞的频率与SLE疾病活动性呈正相关。STING表达及其与TBK 1的共定位在狼疮单核细胞中增加。预先暴露于IFN α可增强单核细胞产生IFN α的能力。抑制雷帕霉素（mTOR）通路的机制靶点可抑制单核细胞产生IFN α，并下调STING及其下游分子的表达。STING途径激活增强诱导的狼疮单核细胞IFN α增强与SLE发病机制相关mTOR通路的抑制下调了单核细胞增强的STING表达和随后的IFN α产生。
Objective. Increased IFN alpha is important in the pathogenesis of SLE. Plasmacytoid dendritic cells are considered the main producer of IFN alpha upon Toll-like receptor pathway activation. However, which cells produce IFN alpha following stimulation with cyclic GMP-AMP synthase (cGAS) and stimulator of IFN genes (STING) in SLE remains unknown. We investigated the IFN alpha producing capacity of myeloid cells under cGAS-STING pathway stimulation.Methods. IFN alpha levels in peripheral blood mononuclear cells from SLE patients and healthy controls stimulated with 2'3'c-GAMP, a stimulator of cGAS-STING, were measured by intracellular cytokine staining and flow cytometry. STING expression and its co-localization with TBK1 were examined by flow cytometry or confocal microscopy. The effects of in vitro exposure to IFN alpha on IFN alpha production and STING expression, and in vitro rapamycin treatment on IFN alpha production and STING, pTBK1 and IRF3 expression were examined.Results. IFN alpha was produced by monocytes, conventional dendritic cells and plasmacytoid dendritic cells upon cGAS-STING pathway activation. The frequency of IFN alpha-producing monocytes positively correlated with SLE disease activity. STING expression and its co-localization with TBK1 were increased in lupus monocytes. Prior exposure to IFN alpha enhanced the IFN alpha-producing capacity of monocytes. Inhibition of the mechanistic target of the rapamycin (mTOR) pathway suppressed IFN alpha production from monocytes and downregulated enhanced STING expression and its downstream molecules.Conclusion. Enhanced IFN alpha from lupus monocytes induced by augmented STING pathway activation is associated with SLE pathogenesis. Suppression of the mTOR pathway downregulated the enhanced STING expression and the subsequent IFN alpha production by monocytes.