Kinetics of membrane raft formation: fatty acid domains in stratum corneum lipid models.
Kinetics of membrane raft formation: fatty acid domains in stratum corneum lipid models.
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膜筏形成动力学：角质层脂质模型中的脂肪酸结构域。
DOI：
10.1021/jp054875h
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Mendelsohn,Richard
中科院分区：
文献类型：
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作者：
Moore,DavidJ;Snyder,RobertG;Rerek,MarkE;Mendelsohn,Richard
皮肤渗透性的主要屏障位于表皮的最外层，角质层（SC）。主要的SC脂质成分是神经酰胺、游离脂肪酸和胆固醇。含有这些成分的三元混合物被广泛用于屏障的物理化学表征。先前的X-射线衍射和红外光谱研究揭示了正交亚细胞中有序脂质链的存在。为了监测富含脂肪酸的区域的形成动力学，本研究采用了改进的方法（J. Phys. Chem.1992，96，10008），该方法被开发用于监测正烷烃混合物中的组分分层。该方法是基于（正交堆积）有序链的红外光谱中的剪切或摇摆模式轮廓的变化。在当前的研究中，神经酰胺（非羟基脂肪酸鞘氨醇神经酰胺或α-羟基脂肪酸鞘氨醇神经酰胺）与链全氘代脂肪酸（棕榈酸或硬脂酸）和胆固醇的等摩尔混合物揭示了氘代脂肪酸链在从发生随机混合的相对高温淬火后的剪切轮廓的时间演变。观察到富含脂肪酸组分的结构域的分离。偏析的动力学对淬火温度和混合物的化学组成敏感。动力学制度方便地编目与幂律的形式P =Ktα，其中P是一个（测量）属性有关的域组成。这些实验中的分层时间尺度与几项研究中观察到的时间相似，这些研究跟踪了SC完整性非热挑战后体内渗透屏障的恢复。当前测量的生理重要性的进一步证据是在本地SC这些阶段的检测。目前的工作构成了第一个直接的，基于结构的确定相关的皮肤脂质屏障模型中的屏障形成的动力学。
The major barrier to permeability in skin resides in the outermost layer of the epidermis, the stratum corneum (SC). The major SC lipid components are ceramides, free fatty acids, and cholesterol. Ternary mixtures containing these constituents are widely used for physicochemical characterization of the barrier. Prior X-ray diffraction and IR spectroscopy studies have revealed the existence of ordered lipid chains packed in orthorhombic subcells. To monitor the kinetics of formation of regions rich in fatty acids, the current study utilizes a modification of the method (J. Phys. Chem.1992,96, 10008) developed to monitor component demixing inn-alkane mixtures. The approach is based on changes in the scissoring or rocking mode contours in the IR spectra of (orthorhombically packed) ordered chains. In the current study, equimolar mixtures of ceramides (either non-hydroxy fatty acid sphingosine ceramide or α-hydroxy fatty acid sphingosine ceramide) with chain perdeuterated fatty acids (either palmitic or stearic acid) and cholesterol reveal a time evolution of the scissoring contour of the deuterated fatty acid chains following quenching from relatively high temperatures where random mixing occurs. Segregation of domains enriched in the fatty acid component is observed. The kinetics of segregation are sensitive to the quenching temperature and to the chemical composition of the mixture. The kinetic regimes are conveniently catalogued with a power law of the formP=KtαwherePis a (measured) property related to domain composition. The time scales for demixing in these experiments are similar to times observed in several studies that have tracked the restoration of the in vivo permeability barrier following nonthermal challenges to SC integrity. Further evidence for the physiological importance of the current measurements is the detection of these phases in native SC. The current work constitutes the first direct, structure-based determination of the kinetics of barrier formation in relevant skin lipid barrier models.