Altered expression of microRNAs targeting Dkk-1 in peripheral blood mononuclear cells of patients with ankylosing spondylitis

Introduction: Ankylosing spondylitis (AS) is a chronic inflammatory disease characterised by new bone formation, and Dickkopf homologue 1 (Dkk-1) may contribute to the ankylosis of the sacroiliac joint as a main regulator of the Wingless (Wnt) pathway. Increasing evidence shows that microRNAs targeting Dkk-1 might play a critical role in the pathogenesis of rheumatic diseases. We aim to investigate alterations in expression of miRNAs targeting Dkk-1 in AS patients in this study. Material and methods: The peripheral blood mononuclear cells (PBMCs) of 20 AS patients and 20 normal controls were collected in our study. Three miRNAs targeting DKK1 including miR-29a, miR-335, and miR-363 were selected and quantitative real-time PCR was used to identify the expression of the three miRNAs in these samples. Correlation analysis was conducted between altered miRNA expression and erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Function Index (BASFI), and mSASSS (modified Stoke Ankylosing Spondylitis Spinal Score). Results: The expression of miR-29a was significantly higher in AS patients than in healthy controls (p < 0.01), while no significance was observed in the expression of miR-335 and miR-363 between AS patients and healthy controls (p > 0.05). No correlation was observed between miR-29a and ESR, CRP, BASDAI, and BASFI (p > 0.05). The elevated miR-29a expression was correlated with disease duration and mSASSS (p < 0.05). Conclusions: MiR-29a might be a useful marker in AS new bone formation and contributes to the regulation of Dkk-1 in Wnt signalling.