LAUSR

Ankylosing spondylitis (AS) is a chronic and progressive immuno-inflammatory disease, which mainly affects the spine and sacroiliac joints and shows a high rate of late disability. Inflammation, bone destruction, and new bone formation are typical pathological changes of AS. AS is dominated byinflammation at the early stage. Whilebone destructionand heterotopic ossification,the two contradictory manifestations of AS, occur at the late stage and reflect the imbalance between osteogenesis and osteoclastogenesis in AS patients. Till now, the pathogenesis of ASremains unclear. MicroRNAs (miRNAs) are a class of highly conserved single-stranded non-coding RNAs (ncRNAs) with a length of about 22 basescharacterized by temporal sequenceand tissue specificity. MiRNAs are key modulators in bone formation, resorption, remodelingand regeneration by regulating the immune responses andthe differentiation and functions of osteoblasts, osteoclasts and chondrocytes. Thepresent review summarizes the roles and potential mechanisms of miRNAs' involvement in AS by regulating immuno-inflammatory responses, bone destruction, heterotopic ossification, cell death and autophagy, and the involving signaling including Wnt/β-catenin and BMP/Smads pathways. In addition, the feasibility of miRNAs as diagnostic biomarkers and therapeutic targets for AS are also discussed.