MicroRNA-125b regulates the expression of aggrecanase-1 (ADAMTS-4) in human osteoarthritic chondrocytes
1 Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
2 Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
3 Department of System Biomedicine, Tokyo Medical and Dental University, 1-5-45 Tsushima, Bunkyo-ku, Tokyo 113-8510, Japan
4 Department of System Biomedicine, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan
Arthritis Research & Therapy 2013, 15:R28 doi:10.1186/ar4164Published: 13 February 2013
Increased expression of aggrecanase-1 (ADAMTS-4) has emerged as an important factor in osteoarthritis (OA) and other joint diseases. This study aimed to determine whether the expression of ADAMTS-4 in human chondrocytes is regulated by miRNA.
MiRNA targets were identified using bioinformatics. Chondrocytes were isolated from knee cartilage and treated with interleukin-1 beta (IL-1β). Gene expression was quantified using TaqMan assays and protein production was determined by immunoblotting. Luciferase reporter assay was used to verify interaction between miRNA and target messenger RNA (mRNA).
In silico analysis predicted putative target sequence of miR-125b on ADAMTS-4. MiR-125b was expressed in both normal and OA chondrocytes, with significantly lower expression in OA chondrocytes than in normal chondrocytes. Furthermore, IL-1β-induced upregulation of ADAMTS-4 was suppressed by overexpression of miR-125b in human OA chondrocytes. In the luciferase reporter assay, mutation of the putative miR-125b binding site in the ADAMTS-4 3'UTR abrogated the suppressive effect of miR125.
Our results indicate that miR-125b plays an important role in regulating the expression of ADAMTS-4 in human chondrocytes and this identifies miR-125b as a novel therapeutic target in OA.