Dietary Glucosylceramide Enhances Tight Junction Function in Skin Epidermis via Induction of Claudin-1

Dietary glucosylceramide increased the expression of claudin-1 in UVB-irradiated mouse epidermis. Sphingosine and phytosphingosine, metabolites of glucosylceramide, increased trans-epithelial electrical resistance, and phytosphingosine increased claudin-1 mRNA expression in cultured keratinocytes. Our results indicate that the skin barrier improvement induced by dietary glucosylceramide might be due to enhancement of tight junction function, mediated by increased expression of claudin-1 induced by sphingoid metabolites.