Background: Rheumatoid arthritis (RA) is a systematic autoimmune disease which may lead to joint dysfunction and disability. Aberrant migration and invasion of fibroblast-like synoviocytes (FLSs) is one of the most predominant etiopathogenesis of RA. Quercetin is a bioflavonoid which is implicated in the development of RA, yet its role in regulating the migration and invasion of FLSs is still elusive. The aim of this study is to investigate the impact of quercetin treatment on migration and invasion of FLSs and the underlying mechanism.Methods: Capacity of migration and invasion of FLSs were assessed using transwell assay. Immunofluorescence assay was used to determine the expression of F-actin. The RNA levels of miR-146a and GATA transcription factor 6 (GATA6) were measured using quantitative real-time PCR. Western blot was used to examine the protein level of GATA6. The correlation between miR-146a and GATA6 was validated using luciferase reporter assay.Results: Transwell assay revealed that the migration and invasion of FLSs were significantly inhibited after quercetin treatment, which was also proved by decreased expression of F-actin. The RNA level of miR-146a was decreased in RA tissues and was negatively related to the expression of GATA transcription factor 6 (GATA6). Quercetin treatment elevated the RNA level of miR-146a, but suppressed the expression of GATA6 in FLSs. Further luciferase reporter assay validated that GATA6 is a downstream target of miR-146a. Besides, miR-146a inhibited the migration and invasion of FLSs, and further GATA6 over-expression abrogated the miR-146a-induced inhibition. In addition, specific anti-miR-146a inhibitor abolished quercetin-mediated suppression of migration and invasion of FLSs.Conclusion: Our study suggested that quercetin suppresses the migration and invasion of FLSs via regulating the miR-146a/GATA6 axis.

中文翻译：

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槲皮素通过靶向类风湿关节炎成纤维样滑膜细胞中的miR-146a / GATA6轴来抑制迁移和侵袭。

背景：类风湿关节炎（RA）是一种系统性自身免疫性疾病，可能导致关节功能障碍和残疾。成纤维样滑膜细胞（FLSs）的异常迁移和侵袭是RA最主要的病因之一。槲皮素是一种生物类黄酮，与RA的发展有关，但在调节FLS迁移和侵袭中的作用仍然难以捉摸。本研究旨在探讨槲皮素治疗对FLSs迁移和侵袭的影响及其潜在机制。方法：采用transwell法评估FLSs迁移和侵袭能力。免疫荧光测定用于确定F-肌动蛋白的表达。使用定量实时PCR测量miR-146a和GATA转录因子6（GATA6）的RNA水平。蛋白质印迹用于检查GATA6的蛋白水平。结果：Transwell分析显示，槲皮素处理后FLSs的迁移和侵袭被显着抑制，F-肌动蛋白的表达降低也证明了miR-146a与GATA6之间的相关性。在RA组织中，miR-146a的RNA水平降低，并且与GATA转录因子6（GATA6）的表达负相关。槲皮素处理提高了miR-146a的RNA水平，但抑制了FLS中GATA6的表达。进一步的荧光素酶报告基因测定证实了GATA6是miR-146a的下游靶标。此外，miR-146a抑制了FLS的迁移和侵袭，进一步的GATA6过表达消除了miR-146a诱导的抑制作用。此外，