Omega-hydroxyceramides are required for corneocyte lipid envelope (CLE) formation and normal epidermal permeability barrier function
Omega-hydroxyceramides are required for corneocyte lipid envelope (CLE) formation and normal epidermal permeability barrier function
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DOI：
10.1046/j.1523-1747.2000.00846.x
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发表时间：
2000-01-01
影响因子：
6.5
通讯作者：
Holleran, WM
中科院分区：
文献类型：
--
作者：
Behne, M;Uchida, Y;Holleran, WM
欧米茄-羟基神经酰胺（欧米茄- ohcer）是表皮角质层中主要的脂质种类。此外，它们的omega-酯化衍生物（酰基）是角质层细胞外片的主要成分，调节皮肤通透性屏障功能。由于表皮omega-OH - Cer似乎是由细胞色素p450依赖的过程产生的，我们确定了一种基于机制的omega-OH -羟基化抑制剂氨基苯并三唑（ABT）对表皮omega-OH - Cer形成和屏障功能的影响。我们首先确定ABT，而不是羟基苯并三唑（OHBT），一种没有P450抑制活性的化学亲缘关系，在培养的人角质形成细胞中抑制[C-14]-乙酸纳入含有ω - oh的Cer物种（与载体处理的对照组相比，抑制率为68.1% +/- 6.9%,p < 0.001），而不改变其他Cer和脂肪酸物种的合成。此外，ABT显著抑制培养的人角质形成细胞中长链脂肪酸的ω -羟基化。局部应用ABT，而不是OHBT，当将ABT应用于无毛小鼠皮肤时，在胶带剥离急性屏障破坏后，导致屏障恢复明显延迟（例如，6小时延迟38.3%），评估为经皮失水增加。abt诱导的屏障异常与：(i)在未结合和共价结合的Cer池中omega-OHCer的数量显著减少；（ii）层状体结构和内容有明显变化；(3)角质层细胞外板层膜结构异常，无细胞毒性迹象。此外，吡啶提取的ABT与载体处理的皮肤，去除所有的细胞外薄片，留下共价附着的脂质，在ABT与载体处理的角质层中显示了许多缺失角质细胞脂质包膜的灶。这些结果为omega-OHCer对表皮通透性功能的重要性提供了第一个直接证据，并进一步表明酰基cer和/或角质细胞脂质包膜是通透性屏障稳态所必需的元素。
Omega-hydroxyceramides (omega-OHCer) are the predominant lipid species of the corneocyte lipid envelope in the epidermis. Moreover, their omega-esterified-derivatives (acylCer) are major components of the stratum corneum extracellular lamellae, which regulate cutaneous permeability barrier function. Because epidermal omega-OHCer appear to be generated by a cytochrome P450-dependent process, we determined the effects of a mechanism-based inhibitor of omega-hydroxylation, aminobenzotriazole (ABT), on epidermal omega-OH Cer formation and barrier function. We first ascertained that ABT, but not hydroxybenzotriazole (OHBT), a chemical relative with no P450 inhibitory activity, inhibited the incorporation of [C-14]-acetate into the omega-OH-containing Cer species in cultured human keratinocytes (68.1% +/- 6.9% inhibition versus vehicle-treated controls; p < 0.001), without altering the synthesis of other Cer and fatty acid species. In addition, ABT significantly inhibited the omega-hydroxylation of very long-chain fatty acids in cultured human keratinocytes. Topical application of ABT, but not OHBT, when applied to the skin of hairless mice following acute barrier disruption by tape-stripping, resulted in a significant delay in barrier recovery (e.g., 38.3% delay at 6 h versus vehicle-treated animals), assessed as increased transepidermal water loss. The ABT-induced barrier abnormality was associated with: (i) a significant decrease in the quantities of omega-OHCer in both the unbound and the covalently bound Cer pools; (ii) marked alterations of lamellar body structure and contents; and (iii) abnormal stratum corneum extracellular lamellar membrane structures, with no signs of cellular toxicity. Furthermore, pyridine-extraction of ABT- versus vehicle-treated skin, which removes all of the extracellular lamellae, leaving the covalently attached lipids, showed numerous foci with absent corneocyte lipid envelope in ABT- versus vehicle-treated stratum corneum. These results provide the first direct evidence for the importance of omega-OHCer for epidermal permeability function, and suggest further that acylCer and/or corneocyte lipid envelope are required elements in permeability barrier homeostasis.