miRNA Functions in Arthritis

MicroRNAs (miRNAs) are classes of non-coding RNA that function as negative regulators of protein-coding gene expression at the post-transcription level. It has been elucidated that the miRNAs play a critical role in a variety of human disease including arthritic diseases such as Rheumatoid arthritis (RA) and Osteoarthritis (OA). RA is a chronic autoimmune disease mainly characterized by the inflammation of synovial tissue that leads to destruction of the joint tissues, bone and cartilage. OA is characterized by the progressive destruction of articular cartilage. Recent studies elucidated that several miRNAs are abnormally expressed in RA and OA, and some of these intimately involved in the pathologies. The present review summarizes the current progress of miRNA synthesis and function, their expression and function in arthritis, especially focused on the well investigated miRNAs, miR-146a and miR-155.