RUNX1 and osteoarthritis: This idea is based on our previous study to prevent cartilage degeneration in the joints of osteoarthritis model mice, where the chondrocytes in the joint cartilage were modified by introducing a cartilage-anabolic factor, runt-related transcription factor-1 (RUNX1), via intraarticular administration of RUNX1-encoding mRNA.10, 11 The modified chondrocytes showed an increase in the expression of cartilage-anabolic markers and proliferation, resulting in the augmentation of the net resistance of the articular cartilage to the mechanical loading.