Different Phase Behavior and Packing of Ceramides with Long (C16) and Very Long (C24) Acyls in Model Membranes: Infrared Spectroscopy Using Deuterated Lipids

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• 作者：Barbora 艩kolov谩 ; Kl谩ra Hudsk谩 ; Petra Pullmannov谩 ; Andrej Kov谩膷ik ; Karel Pal谩t ; Jaroslav Roh ; Jana Fleddermann ; Irina Estrela-Lopis ; Kate艡ina V谩vrov谩
• 刊名：Journal of Physical Chemistry B
• 出版年：2014
• 出版时间：September 4, 2014
• 年：2014
• 卷：118
• 期：35
• 页码：10460-10470
• 全文大小：549K
• ISSN：1520-5207

文摘

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鈥揅24), in the presence or absence of cholesterol sulfate, and at 5鈥?5% 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.