Pro-inflammatory mediators contained with IL-1β, TNF-α, and PGE2 can also enhance the binding activity of NF-κB with Nurr1 promoter, thereby promoting Nurr1 transcription and elevating Nurr1 mRNA and protein level in primary rheumatoid arthritis and normal synoviocytes (McEvoy et al., 2002). Here, NR4A2 is linked to rheumatoid arthritis.