Effects of sphingomyelin/ceramide ratio on the permeability and microstructure of model stratum corneum lipid membranes.
The conversion of sphingomyelin (SM) to a ceramide (Cer) by acid sphingomyelinase (aSMase) is an important event in skin barrier development. A deficiency in aSMase in diseases such as Niemann-Pick disease and atopic dermatitis coincides with impaired skin barrier recovery after disruption. We studied how an increased SM/Cer ratio influences the barrier function and microstructure of model stratum corneum (SC) lipid membranes. In the membranes composed of isolated human SC Cer (hCer)/cholesterol/free fatty acids/cholesteryl sulfate, partial or full replacement of hCer by SM increased water loss. Partial replacement of 25% and 50% of hCer by SM also increased the membrane permeability to theophylline and alternating electric current, while a higher SM content either did not alter or even decreased the membrane permeability. In contrast, in a simple membrane model with only one type of Cer (nonhydroxyacyl sphingosine, CerNS), an increased SM/Cer ratio provided a similar or better barrier against the permeation of various markers. X-ray powder diffraction revealed that the replacement of hCer by SM interferes with the formation of the long periodicity lamellar phase with a repeat distance of d=12.7nm. Our results suggest that SM-to-Cer processing in the human epidermis is essential for preventing excessive water loss, while the permeability barrier to exogenous compounds is less sensitive to the presence of sphingomyelin.
Skin Barrier Research Group, Charles University in Prague, Faculty of Pharmacy, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic. Electronic address: pullmanp@faf.cuni.cz.
Petra
P
Pullmannová
Skin Barrier Research Group, Charles University in Prague, Faculty of Pharmacy, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
Klára
K
Staňková
Skin Barrier Research Group, Charles University in Prague, Faculty of Pharmacy, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
Markéta
M
Pospíšilová
Skin Barrier Research Group, Charles University in Prague, Faculty of Pharmacy, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
Barbora
B
Skolová
Institute of Chemical Technology Prague, Technická 5, 166 28 Prague, Czech Republic.
Jarmila
J
Zbytovská
Skin Barrier Research Group, Charles University in Prague, Faculty of Pharmacy, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
Kateřina
K
Vávrová
D002463:Cell Membrane Permeability; D002518:Ceramides / Q000378:metabolism*; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004817:Epidermis / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000737:chemistry / Q000378:metabolism; D005260:Female; D006801:Humans; D008051:Lipid Bilayers / Q000378:metabolism*; D008563:Membrane Lipids / Q000737:chemistry*; D012867:Skin / Q000737:chemistry / Q000378:metabolism; D013109:Sphingomyelins / Q000378:metabolism*; D014961:X-Ray Diffraction
D002518:Ceramides; D005230:Fatty Acids, Nonesterified; D008051:Lipid Bilayers; D008563:Membrane Lipids; D013109:Sphingomyelins; D002784:Cholesterol
Ceramide; Lipid membrane; Permeability; Sphingomyelin; Stratum corneum model; X-ray diffraction