Glucosylceramide fed mice skin before SDS treatment (0d), after SDS treatment (2d)

Dietary glucosylceramide (GC) improves skin barrier function. To elucidate the molecular mechanisms involved, we used a microarray system to analyze mRNA expression in SDS-treated dorsal skin of hairless mouse. Transepidermal water loss of mouse skin was increased by SDS treatment and the increase was significantly reduced by prior oral administration of glucosylceramides. Microarray-evaluated mRNA expression ratios showed statistically significant increase of expression of genes related to cornified envelope and tight junction formation versus all genes in glucosylceramide-fed/SDS-treated mouse skin. We then examined the contribution of glucosylceramide metabolites to tight junction formation of cultured keratinocytes. SDS treatment of cultured keratinocytes significantly decreased the transepidermal electrical resistance, and the decrease was significantly ameliorated in the presence of sphingosine or phytosphingosine, the major metabolites of glucosylceramide. These results suggest that oral administration of glucosylceramide improves skin barrier function by upregulating genes associated with both cornified envelope and tight junction formation. Two-condition experiment, effect of oral intake of GC on mice skin before SDS treatment (0d), and after SDS treatment(2d), Biological replicates: 3 replicates for 0d, 4 replicates for 2d.