Identification of differentially expressed microRNAs in knee anterior cruciate ligament tissues surgically removed from patients with osteoarthritis

The degradation of cruciate ligaments is frequently observed in degenerative joint diseases, such as osteoarthritis (OA). The present study aimed to identify the differentially expressed microRNAs (miRNAs or miRs) in knee anterior cruciate ligament (ACL) tissues derived from patients with OA and in health subjects (non-OA). By using Affymetrix miRNA 4.0 microarrays, a total of 22 miRNAs (including let-7f-5p, miR-26b-5p and miR-146a-5p) were found to be upregulated, while 17 (including miR-18a-3p, miR-138-5p and miR-485-3p) were downregulated in the osteoarthritic ACL tissues (fold change ≥2, P-value <0.05). The expression levels of 12 miRNAs were validated by quantitative PCR, and the corresponding results revealed an excellent correlation with the microarray data (R(2)=0.889). Genes (such as a disintegrin and metalloproteinase domain with thrombospondin type-1 motifs, bone morphogenetic protein-2, runt related transcription factor-2, collagen-1A1 and 2, interleukin-6 and transforming growth factor-β) involved in cartilage development and remodeling, collagen biosynthesis and degradation, inflammatory response and extracellular matrix homeostasis were predicted as potential targets of the dysregulated miRNAs. Moreover, a large set of putative genes were enriched in OA pathogenesis-associated pathways (such as mitogen-activated protein kinase and vascular endothelial growth factor signaling pathway). Collectively, the data from our study provides novel insight into the ligament injury-related miRNA dysregulation in patients with OA.