Boury-Jamot M, Sougrat R, Tailhardat M, Le Varlet B, Bonté F, Dumas M, Verbavatz J-M
Service de Biophysique des fonctions membranaires, DBJC/SBFM, Bâtiment 532, CEA/Saclay, F-91191 Gif-sur-Yvette, Cedex, France.
Biochim Biophys Acta. 2006 Aug;1758(8):1034-42. doi: 10.1016/j.bbamem.2006.06.013. Epub 2006 Jun 18.
The aquaporins (AQPs) are a family of transmembrane proteins forming water channels. In mammals, water transport through AQPs is important in kidney and other tissues involved in water transport. Some AQPs (aquaglyceroporins) also exhibit glycerol and urea permeability. Skin is the limiting tissue of the body and within skin, the stratum corneum (SC) of the epidermis is the limiting barrier to water loss by evaporation. The aquaglyceroporin AQP3 is abundantly expressed in keratinocytes of mammalian skin epidermis. Mice lacking AQP3 have dry skin and reduced SC hydration. Interestingly, however, results suggested that impaired glycerol, rather than water transport was responsible for this phenotype. In the present work, we examined the overall expression of AQPs in cells from human skin and we reviewed data on the functional role of AQPs in skin, particularly in the epidermis. By RT-PCR on primary cell cultures, we found that up to 6 different AQPs (AQP1, 3, 5, 7, 9 and 10) may be selectively expressed in various cells from human skin. AQP1, 5 are strictly water channels. But in keratinocytes, the major cell type of the epidermis, only the aquaglyceroporins AQP3, 10 were found. To understand the role of aquaglyceroporins in skin, we examined the relevance to human skin of the conclusion, from studies on mice, that skin AQP3 is only important for glycerol transport. In particular, we find a correlation between the absence of AQP3 and intercellular edema in the epidermis in two different experimental models: eczema and hyperplastic epidermis. In conclusion, we suggest that in addition to glycerol, AQP3 may be important for water transport and hydration in human skin epidermis.
水通道蛋白（AQPs）是一类形成水通道的跨膜蛋白家族。在哺乳动物中，通过AQPs进行的水运输在肾脏和其他参与水运输的组织中很重要。一些AQPs（水甘油通道蛋白）也表现出对甘油和尿素的通透性。皮肤是身体的屏障组织，在皮肤内部，表皮的角质层（SC）是防止水分通过蒸发流失的主要屏障。水甘油通道蛋白AQP3在哺乳动物皮肤表皮的角质形成细胞中大量表达。缺乏AQP3的小鼠皮肤干燥，SC水合作用降低。然而，有趣的是，结果表明这种表型是由甘油运输受损而非水运输受损导致的。在本研究中，我们检测了人皮肤细胞中AQPs的整体表达情况，并回顾了AQPs在皮肤，特别是表皮中的功能作用的数据。通过对原代细胞培养物进行逆转录聚合酶链反应（RT-PCR），我们发现多达六种不同的AQPs（AQP1、3、5、7、9和10）可能在人皮肤的各种细胞中选择性表达。AQP1、5是严格的水通道。但在表皮的主要细胞类型角质形成细胞中，仅发现了水甘油通道蛋白AQP3、10。为了了解水甘油通道蛋白在皮肤中的作用，我们研究了从小鼠研究得出的结论与人类皮肤的相关性，即皮肤AQP3仅对甘油运输重要。特别是，我们在两种不同的实验模型：湿疹和增生性表皮中发现，AQP3缺失与表皮细胞间水肿之间存在相关性。总之，我们认为除了甘油外，AQP3可能对人皮肤表皮的水运输和水合作用也很重要。
