Department of General Medicine, Beijing Luhe Hospital, Capital Medical University, Beijing, China.
Department of Anesthesiology, Tongzhou Maternal-Child Health Hospital of Beijing, Beijing, China,
Cells Tissues Organs. 2020;209(2-3):110-119. doi: 10.1159/000508405. Epub 2020 Aug 7.
To discuss how IRF9 affects the fibroblast-like synoviocytes (FLS) in TNF-induced rheumatoid arthritis (RA) via the SIRT-1/NF-κB signaling pathway.
RA-FLS were isolated and divided into control, sh-IRF9, TNF, TNF + sh-Ctrl, TNF + sh-IRF9, TNF + sh-SIRT1, and TNF + sh-IRF9 + sh-SIRT1 groups. Biological features of FLS were evaluated by MTT, wound healing, and Transwell assays, respectively. Cell apoptosis and cycle were assessed flow cytometrically. Inflammatory cytokines were determined through enzyme-linked immunosorbent assay (ELISA), while IRF9 expression and SIRT1/NF-κB signaling pathway activity were measured by Western blotting.
TNF increased IRF9 expression as well as NF-κB signaling activity and down-regulated SIRT1 of RA-FLS. Silencing IRF9 resulted in up-regulation of SIRT1 and blocked NF-κB signaling, with significant decreases in TNF-induced cell viability, migration, and invasion, prominent enhancement in apoptosis and the proportion of cells in G0/G1 phase, but a decrease in the proportion of cells in S and G2/M phases, and reduced levels of inflammatory cytokines. However, these changes were totally abolished after silencing SIRT1, i.e., the IRF9 shRNA-induced inhibitory effect on the growth of RA-FLS was reversed.
Silencing IRF9 curbs the activity of the NF-κB signaling pathway via up-regulating SIRT-1, to further suppress TNF-induced changes in the malignant features of RA-FLS, and the secretion of inflammatory cytokines, with the promoted apoptosis.
探讨干扰素调节因子 9（IRF9）通过 SIRT-1/NF-κB 信号通路对肿瘤坏死因子（TNF）诱导的类风湿关节炎（RA）成纤维样滑膜细胞（FLS）的影响。
分离 RA-FLS 并分为对照组、sh-IRF9 组、TNF 组、TNF+sh-Ctrl 组、TNF+sh-IRF9 组、TNF+sh-SIRT1 组和 TNF+sh-IRF9+sh-SIRT1 组。分别采用 MTT、划痕愈合和 Transwell 实验评估 FLS 的生物学特征。采用流式细胞术评估细胞凋亡和细胞周期。通过酶联免疫吸附试验（ELISA）测定炎性细胞因子，采用 Western blot 测定 IRF9 表达和 SIRT1/NF-κB 信号通路活性。
TNF 增加了 RA-FLS 中的 IRF9 表达以及 NF-κB 信号活性，并下调了 SIRT1。沉默 IRF9 导致 SIRT1 上调并阻断 NF-κB 信号，TNF 诱导的细胞活力、迁移和侵袭显著降低，细胞凋亡和 G0/G1 期细胞比例显著增加，而 S 和 G2/M 期细胞比例降低，炎性细胞因子水平降低。然而，沉默 SIRT1 后这些变化完全被消除，即 IRF9 shRNA 对 RA-FLS 生长的抑制作用被逆转。
沉默 IRF9 通过上调 SIRT-1 抑制 NF-κB 信号通路的活性，从而进一步抑制 TNF 诱导的 RA-FLS 恶性特征和炎性细胞因子的分泌，并促进细胞凋亡。
