Department of Orthopaedics of the First Affiliated Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China.
Department of Joint Surgery, Xi'an Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, 710054, China.
Arthritis Res Ther. 2019 Jun 3;21(1):134. doi: 10.1186/s13075-019-1920-0.
We previously found that high-mobility group box protein 1 (HMGB1) promoted cell proliferation, migration, invasion, and autophagy in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), but little is known about its regulatory mechanism. The aim of this study was to investigate the regulatory mechanism of HMGB1 at the posttranscription level.
Real-time qPCR, CCK-8 cell proliferation assay, transwell cell migration assay, enzyme-linked immunosorbent assay (ELISA), and western blotting were used in this study. The targeting relationship between miRNA and mRNA was presented by the luciferase reporter assay.
MiR-449a was downregulated in RA synovial tissue and inhibited RA-FLS proliferation, migration, and IL-6 production. MiR-449a directly targeted HMGB1 and inhibited its expression. Yin Yang 1(YY1) negatively regulated miR-449a expression and formed a mutual inhibition loop in RA-FLS. MiR-449a inhibited TNFα-mediated HMGB1 and YY1 overexpression and IL-6 production.
Our results reveal the regulatory mechanism of HMGB1 in RA and demonstrate that miR-449a is a crucial molecule in RA pathogenesis and a suitable candidate for miRNA replacement therapies in RA.
我们之前发现高迁移率族蛋白 B1（HMGB1）可促进类风湿关节炎成纤维样滑膜细胞（RA-FLS）的增殖、迁移、侵袭和自噬，但对其调控机制知之甚少。本研究旨在探讨 HMGB1 在转录后水平的调控机制。
本研究采用实时 qPCR、CCK-8 细胞增殖实验、Transwell 细胞迁移实验、酶联免疫吸附实验（ELISA）和 Western blot 等方法。miRNA 与 mRNA 的靶向关系通过荧光素酶报告基因实验进行验证。
miR-449a 在 RA 滑膜组织中表达下调，可抑制 RA-FLS 的增殖、迁移和 IL-6 的产生。miR-449a 可直接靶向 HMGB1 并抑制其表达。Yin Yang 1（YY1）负调控 miR-449a 的表达，并在 RA-FLS 中形成相互抑制的环路。miR-449a 可抑制 TNFα 介导的 HMGB1 和 YY1 过表达及 IL-6 的产生。
本研究揭示了 HMGB1 在 RA 中的调控机制，并表明 miR-449a 是 RA 发病机制中的关键分子，是 RA 中 miRNA 替代治疗的合适候选物。
