title: Ceramides in the skin lipid membranes: length matters.
abstract: Ceramides are essential constituents of the skin barrier that allow humans to live on dry land. Reduced levels of ceramides have been associated with skin diseases, e.g., atopic dermatitis. However, the structural requirements and mechanisms of action of ceramides are not fully understood. Here, we report the effects of ceramide acyl chain length on the permeabilities and biophysics of lipid membranes composed of ceramides (or free sphingosine), fatty acids, cholesterol, and cholesterol sulfate. Short-chain ceramides increased the permeability of the lipid membranes compared to a long-chain ceramide with maxima at 4-6 carbons in the acyl. By a combination of differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, Langmuir monolayers, and atomic force microscopy, we found that the reason for this effect in short ceramides was a lower proportion of tight orthorhombic packing and phase separation of continuous short ceramide-enriched domains with shorter lamellar periodicity compared to native long ceramides. Thus, long acyl chains in ceramides are essential for the formation of tightly packed impermeable lipid lamellae. Moreover, the model skin lipid membranes are a valuable tool to study the relationships between the lipid structure and composition, lipid organization, and the membrane permeability.
authors.affiliation: Charles University in Prague , Faculty of Pharmacy, Heyrovského 1203, 50005 Hradec Králové, Czech Republic.
authors.forename: Barbora
authors.initials: B
authors.lastname: Skolová
authors.forename: Barbora
authors.initials: B
authors.lastname: Janůšová
authors.forename: Jarmila
authors.initials: J
authors.lastname: Zbytovská
authors.forename: Gert
authors.initials: G
authors.lastname: Gooris
authors.forename: Joke
authors.initials: J
authors.lastname: Bouwstra
authors.forename: Petr
authors.initials: P
authors.lastname: Slepička
authors.forename: Pavel
authors.initials: P
authors.lastname: Berka
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Roh
authors.forename: Karel
authors.initials: K
authors.lastname: Palát
authors.forename: Alexandr
authors.initials: A
authors.lastname: Hrabálek
authors.forename: Kateřina
authors.initials: K
authors.lastname: Vávrová
mesh_terms: D000818:Animals; D002518:Ceramides / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry; D006801:Humans; D008563:Membrane Lipids / Q000737:chemistry; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force; D012867:Skin / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002518:Ceramides; D005227:Fatty Acids; D008563:Membrane Lipids; D008567:Membranes, Artificial