Although the severity of arthritis was assessed by the clinical score and ankle joint thickness, and these factors were not affected by CGP57380 treatment (Fig. 6k, l), treatment with an MNK1/2 inhibitor decreased the number of osteoclasts and attenuated bone erosion in the K/BXN serum-induced arthritis model (Fig. 6m, n). Here, MKNK1 is linked to arthritic joint disease.