MicroRNA221-3p modulates Ets-1 expression in synovial fibroblasts from patients with osteoarthritis of temporomandibular joint

Objective: This study aimed to screen differential expression of microRNAs ( miRNAs), and investigate function of the specifically selected miRNA in synovial fibroblasts from patients suffering osteoarthritis of temporomandibular joint ( TMJOA). Methods: MiRNA microarray was used to select differentially expressed miRNAs between TMJOA and normal synovial fibroblasts. The expression of screened miRNA221-3p was quantified using real-time PCR, and its specific target gene was predicted by bioinformatics. After transfection of miRNA221-3p mimics or inhibitor into synovial fibroblasts, the expression of v-Ets avian erythroblastosis virus E26 oncogene homolog 1 ( Ets-1) was detected by immunohistochemistry, real-time PCR and Western blot, respectively. Dual luciferase activity was performed to identify the direct regulation of miRNA221-3p on Ets-1. Interlukin-1 beta ( IL-1 beta) mimics an inflammatory situation. Results: In TMJOA synovial fibroblasts, eight miRNAs were up-regulated and six miRNAs were down-regulated. MiRNA221-3p was the most down-expressed. A sequence in the 3'-untranslated ( 3'-UTR) of Ets-1 complementary to the seed sequence of miRNA221-3p. Elevated expression of Ets-1 associated with attenuation of miRNA221-3p. Over-expression of miRNA221-3p suppressed the activity of a reporter construct containing the 3'-UTR of Ets-1 transcript and inhibited the expression of Ets-1 as well as its downstream molecules, matrix metalloproteinase 1 ( MMP1) and MMP9 in TMJOA synovial fibroblasts. IL-1 beta suppressed the expression of miRNA221-3p in both a dose-dependent and time-dependent manner. Conclusion: The reduction of miRNA221-3p in synovial fibroblasts, attributed from abundance of IL-1 beta in inflamed circumstance, induces Ets-1 up-regulation and then, initiates MMP1 and MMP9 secretion, thereby leading to continuously pathological development in TMJOA. (C) 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.