The impact of ceramides NP and AP on the nanostructure of stratum corneum lipid bilayer. Part I: neutron diffraction and 2H NMR studies on multilamellar models based on ceramides with symmetric alkyl chain length distribution
The impact of ceramides NP and AP on the nanostructure of stratum corneum lipid bilayer. Part I: neutron diffraction and 2H NMR studies on multilamellar models based on ceramides with symmetric alkyl chain length distribution
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DOI：
10.1039/c2sm25420d
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发表时间：
2012-01-01
期刊：
影响因子：
3.4
通讯作者：
Neubert, Reinhard H. H.
中科院分区：
文献类型：
--
作者：
Engelbrecht, Tanja N.;Schroeter, Annett;Neubert, Reinhard H. H.
我们研究了基于植物鞘苷型神经酰胺（CER） [NP]或CER[AP]的三元角质层（SC）脂质模型系统的层状结构，并以胆固醇和硬脂酸为代表的游离脂肪酸补充。对于CER[NP]基膜，中子衍射测量表明两层状相共存，其水化性能明显不同。CER[NP]形成了一个非常刚性和稳定的双层骨架，并且至少部分地隔离在与第二层状相共存的单独相中。在升高的温度下，观察到脂质的结构重组。其中一个层状相消失，而其余相的重复距离增加了约1埃。到目前为止，基于CER[AP]的SC脂质模型膜还没有描述过这种行为。此外，基于CER[NP]或CER[AP]以及胆固醇和过氘硬脂酸的两种SC脂质模型系统的H-2 NMR测量显示，两种样品中都存在高层序状态，强调了植鞘苷型神经酰胺对稳定SC双层结构的正确形成的重要性。然而，基于CER[NP]的三元模型显示出比基于CER[AP]的体系更高的层序状态。我们的研究结果表明，神经酰胺头部基团（带有3个羟基的CER[NP]与带有4个羟基的CER[AP]）的微小变化对这些脂质形成的脂质结构的形态有显著影响。
We investigated the lamellar structure of ternary stratum corneum (SC) lipid model systems based on either the phytosphingosine type ceramide (CER) [NP] or CER[AP], supplemented by cholesterol and stearic acid as representative free fatty acid species. For the CER[NP] based membrane, neutron diffraction measurements revealed the coexistence of two lamellar phases, which markedly differ in their hydration properties. CER[NP] forms an extremely rigid and stable bilayer backbone and is at least partly sequestered in a separate phase which coexists with a second lamellar phase. At increased temperature, a structural re-organization of the lipids was observed. One of the lamellar phases disappeared, while the remaining phase increased its repeat distance by about 1 angstrom. Such a behaviour has not been described for SC lipid model membranes based on CER[AP] so far. Further, H-2 NMR spectroscopic measurements on two SC lipid model systems based on either CER[NP] or CER[AP] in addition to cholesterol and perdeuterated stearic acid revealed a state of high lamellar order present in both samples, emphasizing the importance of the phytosphingosine-type ceramides for the proper formation of stable SC bilayer structures. However, the CER[NP] based ternary model showed a state of higher lamellar order than the CER[AP] based system. Our results demonstrate that slight changes in the ceramides' head groups (CER[NP] with 3 hydroxyl groups vs. CER[AP] with 4 hydroxyl groups) have a dramatic influence on the morphology of the lipid structures formed by these lipids.