IL-1 activates the extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), apetala (AP)-1, and NF-B activating pathways, which stimulate MMP production and leukocyte adhesion to RA FLS [61], whereas oridonin (2–10 M for 24–72 h) suppress RA FLS proliferation in RA [62]. Here, MAPK8 is linked to rheumatoid arthritis.