P053 is a potent, non-competitive and selective ceramide synthase 1 (CerS1) inhibitor wirh an IC50 of 0.5?μM. P053 acts as an endogenous inhibitor of mitochondrial fatty acid oxidation in muscle. Whole-body adiposity regulator.IC50 & Target:IC50: 0.54±0.06 μM (hCerS1), 0.46±0.08 μM (mCerS1), 28.6±0.15 μM (hCerS2), 18.5±0.12 μM (mCerS2), 17.2±0.09 μM (hCerS4), 7.2±0.10 μM (mCerS5), 11.4±0.17 μM (hCerS6)In Vitro: P053 is the first isoform-specific ceramide synthase inhibitor. P053 inhibits CerS1 with nanomolar potency. P053 inhibits different human (h) or murine (m) CerS isoforms hCerS1, mCerS1, hCerS2, mCerS2, hCerS4, mCerS5, and hCerS6 with IC50s of 0.54±0.06, 0.46±0.08, 28.6±0.15, 18.5±0.12, 17.2±0.09, 7.2±0.10, and 11.4±0.17 μM, respectively.In Vivo: P053 (5?mg/kg; administered daily by oral gavage; 7 days, in male C57BL6/J mice ) reduces C18 ceramide levels in skeletal muscle (SkM) .
Daily P053 administration to mice fed a high-fat diet (HFD) increases fatty acid oxidation in skeletal muscle and impedes increases in muscle triglycerides and adiposity, but does not protect against HFD-induced insulin resistance.