FIG 5.

Levels of protein-bound and nonacylated ceramides in the Aldh3a2 Aldh3b2 DKO mouse epidermis. (A and B) Lipids were extracted from the epidermis of WT (n = 3), Aldh3b2 KO (n = 3), and DKO (n = 3) mice at P0, and protein-bound ceramides (A) and ceramides (B) were analyzed via LC-MS/MS. The quantities of each lipid species (according to chain length and saturation) and of total lipids are shown in the left and right panels, respectively. Values presented are means ± SD (*, P < 0.05; **, P < 0.01; Tukey’s test). The structure of each type of lipid is shown to the right of the graph. The structure of a conventional protein-bound ceramide and that of a newly proposed one (28) are shown (upper and lower structures in panel A, respectively). b2 KO, Aldh3b2 KO; n.d., not detected.