MicroRNA expression in osteoarthritis: a meta-analysis.

Osteoarthritis (OA) is one of the most prevalent musculoskeletal diseases globally, leading to chronic disability and poor prognosis. One of the approaches for optimizing OA treatment is to find early effective diagnostic biomarkers. The contribution of microRNAs (miRNAs) in OA progression is now being increasingly recognized. This review provides a comprehensive summary on studies reporting the expression profiling of miRNAs in OA and associated signaling pathways. We performed a systematic search of the Embase, Web of Science, PubMed, and Cochrane library databases. This systematic review is reported according to the PRISMA checklist. Studies which identified miRNAs with aberrant expression compared to controls during OA progression were included, and a meta-analysis was performed. Results from the random effects model were provided as log10 odds ratios (logORs) and 95% confidence intervals. Sensitivity analysis was conducted to confirm the accuracy of the results. Subgroup analysis was conducted based on tissue source. The target genes of miRNAs identified in this study were extracted from the MiRWalk database, and these target genes were enriched in Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. A total of 191 studies reporting 162 miRNAs were included in our meta-analysis. Among them, 36 miRNAs distributed across 96 studies were expressed in the same direction in at least two studies (13 up-regulated and 23 down-regulated). Subgroup analysis of tissue source revealed that the highest number of studies was conducted using articular cartilage, where the most up-regulated miRNAs were miR-146a-5p (logOR 7.355; P < 0.001) and miR-34a-5p (logOR 6.955; P < 0.001), and the most down-regulated miRNAs were miR-127-5p (logOR 6.586; P < 0.001) and miR-140-5p (logOR 6.373; P < 0.001). Enrichment analysis of 752 downstream target genes of all identified miRNAs was performed, and the regulatory relationships among them were displayed. Mesenchymal stem cells and transforming growth factor-β were found to be the most important downstream effectors regulated by miRNA in OA. This study highlighted the importance of miRNA signaling in OA progression and identified a number of prominent miRNAs including miR-146a-5p, miR-34a-5p, miR-127-5p, and miR-140-5p which might be considered as potential biomarkers for OA.