Glucosylated cholesterol in skin: synthetic role of extracellular glucocerebrosidase.

The existence of glucosylated cholesterol (GIcChol) in tissue has recently been recognized. GlcChol is generated from glucosylceramide (GlcCer) and cholesterol through transglucosylation by two retaining beta-glucosidases, GBA and GBA2. Given the abundance of GBA, GlcCer and cholesterol in the skin's stratum corneum (SC), we studied the occurrence of GlcChol. A significant amount of GlcChol was detected in SC (6 pmol/mg weight). The ratio GlcChol/GlcCer is higher in SC than epidermis, 0.083 and 0.011, respectively. Examination of GlcChol in patients with Netherton syndrome revealed comparable levels (11 pmol/mg). Concluding, GlcChol was identified as a novel component in SC and is likely locally metabolized by GBA. The physiological function of GlcChol in the SC warrants future investigation.