Interestingly, our study demonstrated that exposure of AF cells to CTS at low (0.1 Hz) and high (2.0 Hz) frequencies induced a significant increase in the gene expression of Prg4. Lubricin, the protein encoded by Prg4, is a large mucinous glycoprotein that serves as the primary boundary lubricant for articular cartilage75 and its expression has been found to be protective against the development of osteoarthritis.76 Here, PRG4 is linked to osteoarthritis.