SIK-IN-1 (Compound 53) is an inhibitor for salt-inducible kinase ( SIK ), which inhibits SKI1, SIK2 and SIK3 with IC 50 s of 0.1, 0.4 and 1.5 nM, respectively. SIK-IN-1 inhibits the release of TNFa with IC 50 of 0.5 nM, stimulates the LPS -induced IL-10 release with EC 50 of 4 nM in human macrophages.