PDE4-IN-1 is a PDE4 inhibitor with high potency (IC50 : 8.6 nM) and selectivity over other PDE subtypes. PDE4-IN-1 inhibits the release of inflammatory cytokines and chemokines. PDE4-IN-1 greatly restores impaired cAMP-CREB signaling pathway. PDE4-IN-1 inhibits proliferation and promotes differentiation to reverse the formation of psoriasis[1].