In early RA, pro-inflammatory cytokines, such as IL-1, IL-6, IL-8, and TNF-α, actively induce osteoclastogenesis through both canonical RANK/RANKL/OPG signaling and alternative pathways, including the Wnt/DKK1/sclerostin-mediated suppression of osteoblast activity. Here, DKK1 is linked to rheumatoid arthritis.