(A) Potential target genes for miR-181a-5p and miR-4454 were identified using mirDIP version 2, focusing only on middle third, top third, and top 1% of targets. The microRNA (miRNA) gene network was visualized using NAViGaTOR version 2.3 and highlights shared targets (central nodes in the network) and individual target predictions (left and right lists). Thick red edge signifies the top 1% of prediction (corresponding genes are highlighted with red and named); purple edge signifies top-third predictions; all other edges correspond to middle third predictions. Shared targets predicted with top-third hits are highlighted. (B) RT-PCR analysis of zinc finger 440 (ZNF440) expression in facet joint osteoarthritis (FJ OA) chondrocytes treated with miR-181a-5p or miR-4454 mimic compared with control mimic (n = 6/treatment). *P < 0.05, comparing control mimic vs. miR-181a-5p or miR-4454 mimic, as determined by 2-tailed Student’s t tests. (C) RT-PCR analysis ZNF440 expression of FJ chondrocytes treated with (+) or without (–) IL-1β and miR-181a-5p, miR-4454, or control inhibitors (n = 7/treatment). **P < 0.01, control inhibitor with IL-1β vs. control inhibitor without IL-1β treatment; †P < 0.05, ††P < 0.01, control inhibitor vs. miR-181a-5p or miR-4454 inhibitor in the presence of IL-1β, as determined by 1-way analysis of variance followed by Tukey’s post-hoc tests. (D) The most significantly enriched pathways for miR-181a-5p and miR-4454 targets using randomization test include NF-κB pathways, as identified by pathDIP version 1.0. (E) Immunoblot analysis of phosphorylation of Ser536 on NF-κB-p65 (p-p65) in FJ chondrocytes treated with or without IL-1β. (F) Immunoblot analysis of p-p65 and IκBα in FJ chondrocytes treated with miR-181a-5p, miR-4454, or control mimics. (E and F) Representative blots from n = 4 separate blots. Full uncut blots are shown in the supplemental figure. *P < 0.05, **P < 0.01, compared with untreated or control mimic, as determined by 2-tailed Student’s t test. (G) Immunoblot analysis of p-p65 in response to miR-181a-5p mimic or miR-4454 mimic and/or ZNF440 siRNA. Representative blot from n = 4 separate blots. Full uncut blots are shown in the supplemental figure. *P < 0.05, control mimic/control siRNA vs. miR-181a-5p mimic/control siRNA or miR-4454 mimic/control siRNA, †P < 0.05, miR-181a-5p mimic/control siRNA vs. miR-181a-5p/ZNF440 siRNA treatment. ^¶P < 0.05, miR-4454 mimic/control siRNA vs. miR-4454 mimic/ZNF siRNA treatment, as determined by 1-way analysis of variance followed by Tukey’s post-hoc tests. For data presented as box-and-whiskers plots, horizontal lines and cross marks indicate the medians and the means, boxes indicate 25th to 75th percentiles, and whiskers indicate minimum and maximum values of the data set. See also Supplemental Figure 2 and Supplemental Table 4 and 5.