|Budget Amount *help
¥2,500,000 (Direct Cost : ¥2,500,000)
Fiscal Year 1999 : ¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1998 : ¥1,300,000 (Direct Cost : ¥1,300,000)
The epidermis contains very unique ceramides (Cer), in which very long-chain (C24-32) N-acyl fatty acid groups are omega hydroxylated (ω-OH) that may be esterified to linoleic acid. In the stratum corneum, theseω-hydroxylated Cer, which result from the hydrolysis ofω-OH-glucosylCer precursors, are critical components of the mammalian permeability barrier. To delineate the metabolic pathway for the generation of these unique epidermal ceramides, I determined the effects of both an inhibitor of carbon chain elongation(Minimoidin), and a Cer synthase inhibitor (Fumonisin B1) on the formation ofω-OH-Cer in cultured human keratinocytes. As expected, Minimoidin inhibited the synthesis ofω-OH-Cer. Moreover, Fumonisin B1 blocked both Cer and AcylCer formation, but increasedω-OH free fatty acid fraction, indicating the fatty acid as likely substrate forω-hydroxylation. In summary, these results indicate that the formation ofω-OH ceramides in mammalian epidermis proceeds stepwise, with hydroxylation of very-long chain fatty acids preceding Cer synthesis.
Then I measured the amount of Ceramide l(Cer 1 : acylceramide) in three-dimensional culture of mammalian keratinocyte before and after the formation of cornified cell layer. The result indicated that Cer 1 increased with the formation of cornified layer.