Figure 6.

N-palmitoyl serinol (PS) particularly stimulates production of ceramides with long-chain fatty acids (FA) through a CB1-dependent mechanism. HaCaT KC were pretreated with IL-4 (50 ng/mL) for 20 h, followed by incubation with exogenous PS (25 μM) with or without CB1 inhibitor (AM-251, 10 μM) for 4 h. Ceramides with different carbon lengths (C22–C26, (A–E), respectively) were assessed by the LC-MS/MS system. Statistical significance was calculated using the unpaired Student’s t-test, and significance was defined as * p < 0.01 vs. vehicle control (or untreated control).