MMP1 and rheumatoid arthritis: IL20 encodes a proinflammatory cytokine involved in the pathogenesis of inflammatory diseases, such as psoriasis, rheumatoid arthritis, and atherosclerosis, by inducing factors such as TNF-α, IL-1β, MMP-1/13, and MCP-1, and plays important roles in regulating angiogenesis, osteoblastogenesis, and osteoclastogenesis [82, 83].