Haftek M, Simon M, Kanitakis J, Maréchal S, Claudy A, Serre G, Schmitt D
INSERM U346/CNRS Human Skin and Immunity, Lyon, France.
Br J Dermatol. 1997 Dec;137(6):864-73.
The stratum corneum (SC) has long been considered as a sort of inert membrane destined to be shed at the surface of the epidermis. During the last two decades, however, several lines of evidence have been reported, suggesting that active physical and chemical changes take place in the horny layer despite the absence of intracytoplasmic organelles. In particular, processing of filaggrin, replacement of the plasma membrane by a ceramide envelope and constant, progressive modification of extracellular lipid multilayers have been put forward. Recently, attention has focused on the intercellular junctions, which may be involved in the regulation of SC desquamation. Corneodesmosin, a newly discovered protein of s.c. desmosomes (corneodesmosomes), is synthesized at the latest stages of keratinocyte differentiation and persists between the horny cells until desquamation occurs. In the present study, we performed immunohistochemical and immuno-ultrastructural investigations on corneodesmosin expression in various skin lesions characterized by abnormal production and/or retention of the horny layer. Our results suggest that corneodesmosin expression is independent from profilaggrin synthesis. We found corneodesmosin in almost all morphologically recognizable corneodesmosomal structures and specifically those which persisted up to the SC surface. Hyperkeratotic lesions which are characterized by an increased number of junctions showed intense immunoreactivity with anticorneodesmosin antibody. A complete absence of corneodesmosin was not observed in any disease. This finding, together with our previous biochemical studies, suggests that corneodesmosin may exert a protective function against proteolytic degradation of corneodesmosomes both in normal skin and in the pathological horny layer.
长期以来，角质层（SC）一直被视为一种注定要在表皮表面脱落的惰性膜。然而，在过去二十年中，有多项证据表明，尽管角质层缺乏胞浆内细胞器，但仍会发生活跃的物理和化学变化。特别是，提出了丝聚合蛋白的加工、由神经酰胺包膜替代质膜以及细胞外脂质多层膜的持续渐进修饰。最近，人们的注意力集中在细胞间连接上，其可能参与角质层脱屑的调节。角桥粒芯蛋白是一种新发现的表皮角质形成细胞桥粒（角桥粒）蛋白，在角质形成细胞分化的最后阶段合成，并在角质形成细胞之间持续存在直至脱屑发生。在本研究中，我们对角桥粒芯蛋白在各种以角质层产生异常和/或滞留为特征的皮肤病变中的表达进行了免疫组织化学和免疫超微结构研究。我们的结果表明，角桥粒芯蛋白的表达与前丝聚合蛋白的合成无关。我们在几乎所有形态上可识别的角桥粒结构中发现了角桥粒芯蛋白，特别是那些一直持续到角质层表面的结构。以连接数量增加为特征的角化过度性病变与抗角桥粒芯蛋白抗体呈强烈免疫反应。在任何疾病中均未观察到角桥粒芯蛋白完全缺失。这一发现与我们之前的生化研究一起表明，角桥粒芯蛋白可能在正常皮肤和病理性角质层中对角桥粒的蛋白水解降解发挥保护作用。
