Upregulated MicroRNA-155 Expression in Peripheral Blood Mononuclear Cells and Fibroblast-Like Synoviocytes in Rheumatoid Arthritis

• Main Authors: Li Long, Ping Yu, Yanying Liu, Shiyao Wang, Ru Li, Jinxia Shi, Xiaoping Zhang, Yanmei Li, Xiaolin Sun, Bin Zhou, Liufu Cui, Zhanguo Li
• Format: Article
• Language: English
• Published: Hindawi Limited 2013-01-01
• Series: Clinical and Developmental Immunology
• Online Access: http://dx.doi.org/10.1155/2013/296139

Objective. This study was to screen for the miRNAs differently expressed in peripheral blood mononuclear cells (PBMC) of RA, to further identify the expression of miR-155 in RA PBMC and fibroblast-like synoviocytes (FLS), and to evaluate the function of miR-155 in RA-FLS. Methods. Microarray was used to screen for differentially expressed miRNAs in RA PBMC. miR-155 expression in PBMC and FLS of RA were identified by real-time PCR. Enforced overexpression and downexpression of miR-155 were used to investigate the function of miR-155 in RA-FLS. Expression of IKBKE which was previously identified as the actual target of miR-155 was examined by Western blot and real-time PCR in RA-FLS. Results. miR-155 levels were increased in both PBMC and FLS of RA and could be induced by TNF-α. Upregulation of miR-155 decreased MMP-3 levels and suppressed proliferation and invasion of RA-FLS. Inverse relationship between the expressions of miR-155 and the MMPs production-related protein IKBKE was found. Conclusion. An inflammatory milieu may alter miRNA expression profiles in rheumatoid arthritis. miR-155 is upregulated in RA-FLS, and it may be a protective factor against the inflammatory effect in part by attenuating expression of IKBKE.