Department of Medical Research, Taichung Veterans General Hospital, Taichung, 407, Taiwan.
Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
Sci Rep. 2021 Aug 3;11(1):15676. doi: 10.1038/s41598-021-95028-0.
Modulation of miRNAs and neutrophil extracellular traps (NETs) formation are both implicated in inflammatory disorders. Adult-onset Still's disease (AOSD) is a systemic autoinflammatory disease with neutrophilic leukocytosis and unknown etiology. Although the NETs formation is elevated in AOSD patients, the regulatory roles of miRNAs in NETs formation in AOSD remains unclear. We revealed that the circulating levels of IL-18, NETs, and miR-223 were significantly higher in active AOSD patients, compared with inactive AOSD patients or healthy controls (P < 0.005). Moreover, IL-18 increased calcium influx into neutrophils, which led to mitochondrial ROS (mROS) production and NETs formation. Elevated levels of NETs-DNA could induce miR-223 expression in neutrophils through activating Toll-like receptor 9. The upregulated miR-223 expression in neutrophils suppressed mROS production by blocking calcium influx, and subsequently inhibited IL-18-mediated NETs formation. Besides, the increased neutrophil-derived exosomal miR-223 levels were observed in active AOSD patients compared with healthy controls (P < 0.005). Our in vitro assays demonstrated that the neutrophil-derived small extracellular vesicles carried miR-223, which could repress IL-18 production in macrophages. Together, these results suggest a fine-tuned mechanism between inflammatory (IL-18 induced NETs) and anti-inflammatory (miR-223) factors in AOSD. MiR-223, mROS inhibitors, and calcium channel blockers are the potential therapeutics for autoinflammatory diseases such as AOSD.
miRNAs 的调节和中性粒细胞胞外诱捕网（NETs）的形成都与炎症性疾病有关。成人Still 病（AOSD）是一种以中性粒细胞白细胞增多和病因不明为特征的全身性自身炎症性疾病。虽然 AOSD 患者的 NETs 形成增加，但 miRNA 在 AOSD 中对 NETs 形成的调节作用尚不清楚。我们发现，与活动期 AOSD 患者相比，静止期 AOSD 患者或健康对照者的循环 IL-18、NETs 和 miR-223 水平显著升高（P<0.005）。此外，IL-18 增加了中性粒细胞内钙流入，导致线粒体 ROS（mROS）产生和 NETs 形成。升高的 NETs-DNA 可以通过激活 Toll 样受体 9 诱导中性粒细胞中 miR-223 的表达。中性粒细胞中上调的 miR-223 表达通过阻断钙流入抑制 mROS 产生，从而抑制 IL-18 介导的 NETs 形成。此外，与健康对照者相比，活动期 AOSD 患者的中性粒细胞衍生的外泌体 miR-223 水平升高（P<0.005）。我们的体外实验表明，中性粒细胞衍生的小细胞外囊泡携带 miR-223，可抑制巨噬细胞中 IL-18 的产生。综上所述，这些结果表明 AOSD 中存在炎症（IL-18 诱导的 NETs）和抗炎（miR-223）因子之间的精细调节机制。miR-223、mROS 抑制剂和钙通道阻滞剂可能是治疗 AOSD 等自身炎症性疾病的潜在疗法。
