Fourth Military Medical University, Xi'an, China.
Xijing Hospital, Fourth Military Medical University, Xi'an, China.
Arthritis Rheumatol. 2020 Jun;72(6):943-956. doi: 10.1002/art.41205. Epub 2020 May 2.
This study was undertaken to uncover the pathophysiologic role of discoidin domain receptor 2 (DDR-2), a putative fibrillar collagen receptor, in inflammation promotion and joint destruction in rheumatoid arthritis (RA).
In synovial tissue from patients with RA and from mice with collagen antibody-induced arthritis (CAIA) (using Ddr2 and DBA/1 mice), gene and protein expression levels of DDR-2, interleukin-15 (IL-15), and Dkk-1 were measured by quantitative reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemistry. Gene knockdown of DDR2 in human RA fibroblast-like synoviocytes (FLS) was conducted via small interfering RNA. Interaction between the long noncoding RNA H19 and microRNA 103a (miR-103a) was assessed in RA FLS using RNA pulldown assays. Cellular localization of H19 was examined using fluorescence in situ hybridization assays. Chromatin immunoprecipitation and dual luciferase reporter assays were applied to verify H19 transcriptional and posttranscriptional regulation by miR-103a.
DDR2 messenger RNA (mRNA) expression was significantly associated with the levels of IL-15 and Dkk-1 mRNA in the synovial tissue of RA patients (r = 0.2022-0.3293, all P < 0.05; n = 33) and with the serum levels of IL-15 and Dkk-1 in mice with CAIA (P < 0.05). In human RA FLS, activated DDR-2 induced the expression of H19 through c-Myc. Moreover, H19 directly interacted with and promoted the degradation of miR-103a.
These results indicate a novel role for activated DDR-2 in RA FLS, showing that DDR-2 is responsible for regulating the expression of IL-15 and Dkk-1 in RA FLS and is involved in the promotion of inflammation and joint destruction during pathophysiologic development of RA. Moreover, DDR-2 inhibition, acting through the H19-miR-103a axis, leads to reductions in the inflammatory reaction and severity of joint destruction in mice with CAIA, suggesting that inhibition of DDR-2 may be a potential therapeutic strategy for RA.
本研究旨在揭示盘状结构域受体 2（DDR-2）在类风湿关节炎（RA）炎症促进和关节破坏中的病理生理作用。
在 RA 患者和胶原抗体诱导性关节炎（CAIA）小鼠的滑膜组织中，通过定量逆转录聚合酶链反应、Western 印迹和免疫组织化学检测 DDR-2、白细胞介素 15（IL-15）和 Dkk-1 的基因和蛋白表达水平。采用小干扰 RNA 对人 RA 成纤维样滑膜细胞（FLS）中的 DDR2 进行基因敲低。应用 RNA 下拉实验评估 RA FLS 中长链非编码 RNA H19 与 microRNA 103a（miR-103a）之间的相互作用。使用荧光原位杂交实验检测 H19 的细胞定位。应用染色质免疫沉淀和双荧光素酶报告基因检测验证 miR-103a 对 H19 的转录和转录后调控。
DDR2 信使 RNA（mRNA）表达与 RA 患者滑膜组织中 IL-15 和 Dkk-1 mRNA 水平显著相关（r = 0.2022-0.3293，均 P < 0.05；n = 33），与 CAIA 小鼠血清中 IL-15 和 Dkk-1 水平也显著相关（P < 0.05）。在人 RA FLS 中，激活的 DDR-2 通过 c-Myc 诱导 H19 的表达。此外，H19 直接相互作用并促进 miR-103a 的降解。
这些结果表明，在 RA FLS 中，激活的 DDR-2 发挥了新的作用，表明 DDR-2 负责调节 RA FLS 中 IL-15 和 Dkk-1 的表达，并参与 RA 病理生理发展过程中炎症和关节破坏的促进。此外，CAIA 小鼠中 DDR-2 抑制通过 H19-miR-103a 轴导致炎症反应和关节破坏严重程度降低，提示抑制 DDR-2 可能是 RA 的一种潜在治疗策略。
