Dual specificity phosphatase 1 has a protective role in osteoarthritis fibroblast‑like synoviocytes via inhibition of the MAPK signaling pathway.

Increasing evidence indicates the important role of inflammation in the pathogenesis and progression of osteoarthritis (OA). Dual specificity phosphatase 1 (DUSP1), a negative regulator of the mitogen‑activated protein kinase (MAPK) signaling pathway, has anti‑inflammatory properties. In the present study, the expression of DUSP1 was investigated in human OA fibroblast‑like synoviocytes (FLSs), human normal FLSs and OA FLSs pretreated with dexamethasone at the mRNA and protein levels. Then, the activation of MAPK pathway proteins and the expression of matrix metalloproteinase‑13 (MMP‑13) and cyclooxygenase‑2 (COX‑2) were measured by western blot analysis in the three groups of cells. Dexamethasone induced the expression of DUSP1 and inhibited the activation of the MAPK pathway and reduced the expression of MMP‑13 and COX‑2 in OA FLSs. However, the role of DUSP1 remained unclear. To clarify this, the effects of overexpression of DUSP1 in OA FLSs were determined using a DUSP1‑overexpressing lentivirus. The results demonstrated that overexpression of DUSP1 in OA FLSs inhibited the activation of the MAPK pathway and expression of OA‑associated mediators. The findings of the present study indicate that DUSP1 has a protective role in OA FLSs and may be a potential target in the treatment of OA.