As for skeletal-related diseases, CX3CR1 has been implicated in rheumatoid arthritis (RA), osteoarthritis (OA), intervertebral disc degeneration (IDD), and bone metastasis of cancer, primarily through its roles in adhering to fibroblast-like synoviocytes (FLSs), endothelial cells, cancer cells, enhancing osteoclastogenesis, osteogenesis, and promoting inflammatory responses (43–47). This evidence concerns the gene CX3CR1 and rheumatoid arthritis.