SPHINGOLIPID METABOLISM IN ORGANOTYPIC MOUSE KERATINOCYTE CULTURES
SPHINGOLIPID METABOLISM IN ORGANOTYPIC MOUSE KERATINOCYTE CULTURES
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DOI：
10.1111/1523-1747.ep12514333
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发表时间：
1990-12-01
影响因子：
6.5
通讯作者：
DOWNING, DT
中科院分区：
文献类型：
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作者：
MADISON, KC;SWARTZENDRUBER, DC;DOWNING, DT
神经酰胺是角膜层间脂质层状层的主要成分，构成表皮渗透性屏障。 只有猪和人类表皮神经酰胺已被广泛表征，并且先前尚未研究过培养的角质形成细胞的神经酰胺的结构。 在目前的研究中，我们首次通过器官抬起的小鼠角质形成细胞培养物合成的神经酰胺，并将其与完整小鼠表皮的神经酰胺进行了比较。 小鼠表皮和培养物均包含五个神经酰胺，神经酰胺1是极性最小的，而神经酰胺5是极性的。 神经酰胺1是一组酰基酰胺，即具有酯连接的非羟基脂肪酸的非常长的链欧米茄 - 羟基甲酰胺。 神经酰胺2包含中长长饱和的非羟基脂肪酸。 （在培养中，神经酰胺2条带分为两个部分，其稍微更高的极性神经酰胺2'包含短链饱和的非羟基脂肪酸。）神经酰胺5含有短链α-羟基脂肪酸。 神经酰胺1、2和5的结构与猪和人类表皮的结构相似。 小鼠表皮神经酰胺3非常不寻常，含有β-羟基脂肪酸，这种结构以前在哺乳动物的神经酰胺中未鉴定。相反，培养神经酰胺3由欧米茄羟基脂肪酸组成，其链长分布与Ceramide 1相似。小鼠神经酰胺4由具有色谱迁移率的脂肪酸组成，类似于羟基脂肪酸，但具有不同的化学反应性；它只是部分表征。 培养神经酰胺4的数量太小而无法进行分析。 小鼠表皮中的所有神经酰胺和培养基中仅包含鞘氨醇碱，而猪和人类神经酰胺也含有植物磷酸化合物。 这些结果表明，哺乳动物物种之间发生了相当多的神经酰胺结构，并且培养的角质形成细胞只能部分再现体内神经酰胺的体内补体。 使用角质形成细胞培养物中标记的丝氨酸，我们还证明了神经酰胺的从头合成以及在升起培养物的末端分化期间，标记从葡萄糖基酶转移到神经酰胺。 最近在猪和人表皮中表征的共价结合的角膜细胞脂质包膜也存在于小鼠表皮中，并由升起的培养物复制。 非常长的链欧米茄 - 羟基甲酰胺是培养中的主要结合脂质和标记研究，表明它们源自可行表皮中合成的神经酰胺。
Ceramides are the dominant component of the stratum corneum intercellular lipid lamellae, which constitute the epidermal permeability barrier. Only pig and human epidermal ceramides have been extensively characterized and the structures of the ceramides of cultured keratinocytes have not been previously investigated. In the present studies, we have characterized the ceramides synthesized by organotypic lifted mouse keratinocyte cultures for the first time and compared them to the ceramides of intact mouse epidermis. Both mouse epidermis and cultures contained five ceramides, ceramide 1 being the least polar and ceramide 5 the most polar. Ceramide 1 was a group of acylceramides, i.e., very-long-chain omega-hydroxyceramides with an ester-linked nonhydroxy fatty acid. Ceramide 2 contained medium-length saturated nonhydroxy fatty acids. (In culture, the ceramide 2 band was split into two parts with the slightly more polar ceramide 2' containing short-chain saturated nonhydroxy fatty acids.) Ceramide 5 contained short-chain alpha-hydroxy fatty acids. The structures of ceramides 1, 2, and 5 were analagous to those of pig and human epidermis. Mouse epidermal ceramide 3 was quite unusual, containing beta-hydroxy fatty acids, a structure not previously identified among mammalian ceramides. In contrast, culture ceramide 3 was composed of omega-hydroxy fatty acids with a chain-length distribution similar to that of ceramide 1. Mouse ceramide 4 was composed of fatty acids with chromatographic mobility similar to hydroxy fatty acids but with different chemical reactivity; it remains only partially characterized. Culture ceramide 4 was present in quantities too small for analysis. All ceramides in mouse epidermis and cultures contained only sphingosine bases, whereas pig and human ceramides also contain phytosphingosine. These results indicate that considerable diversity of ceramide structures occurs among mammalian species and that cultured keratinocytes may only partially reproduce the in vivo complement of ceramides. Using labeled serine in keratinocyte cultures, we have also demonstrated the de novo synthesis of ceramides and the transfer of label from glucosylceramides to ceramides during terminal differentiation of lifted cultures. The covalently bound corneocyte lipid envelope, which has recently been characterized in pig and human epidermis, was also present in mouse epidermis and was reproduced by the lifted cultures. Very-long-chain omega-hydroxyceramides were the dominant bound lipid and labeling studies in culture indicated that they were derived from ceramides synthesized in the viable epidermis.