Inhibition of the arthritis score of CIA mice, reduction of paw swelling and restored mouse body weightSuppression of FLS proliferation, secretion inhibition of IL-1β, IL-6 and IL-8 and reduction of the expression of β-catenin, fibronectin and MMP-3 in vitroInhibition of the Wnt/β-catenin pathway by binding to FZD4 and blocking the circPTN/miR-145-5p/FZD4 signal axis. Here, FN1 is linked to arthritic joint disease.