Inhibition of S1P1/3 has been shown to reduce the proliferation, migration, invasion, and pro-inflammatory cytokine release in MH7A cells, a human RA synovial cell line, whereas S1P2 suppression primarily affects cell invasion and the release of pro-inflammatory IL-1β and prostaglandin E2 [28]. Here, S1PR2 is linked to rheumatoid arthritis.