title: Different phase behavior and packing of ceramides with long (C16) and very long (C24) acyls in model membranes: infrared spectroscopy using deuterated lipids.
abstract: Ceramides (Cer) are the central molecules in sphingolipid metabolism that participate in cellular signaling and also prevent excessive water loss by the skin. Previous studies showed that sphingosine-based Cer with a long 16C chain (CerNS16) and very long 24C-chain ceramides (CerNS24) differ in their biological actions. Increased levels of long CerNS16 at the expense of the very long CerNS24 have been found in atopic dermatitis patients, and this change correlated with the skin barrier properties. To probe the membrane behavior of the long CerNS16 and the very long chain CerNS24, we studied their interactions with fatty acids and cholesterol in model stratum corneum membranes using infrared spectroscopy. Using Cer with deuterated acyls and/or deuterated fatty acids, we showed differences in lipid mixing, packing, and thermotropic phase behavior between long and very long Cer. These differences were observed in the presence of lignoceric acid or a heterogeneous fatty acid mixture (C16-C24), in the presence or absence of cholesterol sulfate, and at 5-95% humidity. In these membranes, very long CerNS24 prefers an extended (splayed-chain) conformation in which the fatty acid is associated with the very long Cer chain. In contrast, the shorter CerNS16 and fatty acids are mostly phase separated.
authors.affiliation: Skin Barrier Research Group, Faculty of Pharmacy in Hradec Králové, Charles University in Prague , Heyrovského 1203, 50005 Hradec Králové, Czech Republic.
authors.forename: Barbora
authors.initials: B
authors.lastname: Školová
authors.forename: Klára
authors.initials: K
authors.lastname: Hudská
authors.forename: Petra
authors.initials: P
authors.lastname: Pullmannová
authors.forename: Andrej
authors.initials: A
authors.lastname: Kováčik
authors.forename: Karel
authors.initials: K
authors.lastname: Palát
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Roh
authors.forename: Jana
authors.initials: J
authors.lastname: Fleddermann
authors.forename: Irina
authors.initials: I
authors.lastname: Estrela-Lopis
authors.forename: Kateřina
authors.initials: K
authors.lastname: Vávrová
mesh_terms: D002518:Ceramides / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry*; D002788:Cholesterol Esters / Q000737:chemistry; D004817:Epidermis / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry*; D006813:Humidity; D006860:Hydrogen Bonding; D008566:Membranes / Q000737:chemistry*; D008954:Models, Biological; D008958:Models, Molecular; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D002518:Ceramides; D002788:Cholesterol Esters; D005227:Fatty Acids; D002784:Cholesterol; C007045:cholesteryl sulfate; C010210:lignoceric acid