The osmolyte strategy of ageing skin

皮肤提供了整个身体和外界之间的屏障，防止失控的水分流失。没有皮肤，陆地生物的生命就不可能存在，因为水会不断地把皮肤留给外界环境。虽然皮肤内调节水分流失的结构成分已经被很好地表征，但表皮皮肤细胞（角质形成细胞）内调节水分稳态的细胞机制尚未被充分探索。皮肤细胞控制自身稳态的一种机制是将有机渗透物运输到细胞质中以应对水分胁迫。除了保存水分外，渗透物还有其他功能，包括稳定蛋白质结构和抗氧化作用，这些都是整体细胞健康的基础。皮肤脱水在衰老过程中很常见，会导致干燥和炎症。我们的假设是，在衰老的过程中，皮肤失去了合成或运输渗透物的能力。这可能也适用于其他不易接近的器官，因为调节细胞含水量的能力是所有器官系统的基础。在这个项目中，我们将描述渗透转运蛋白在老年人和年轻人皮肤中的表达和分布，并研究特定渗透转运蛋白对老年人和年轻人培养的角质形成细胞中细胞体积控制、氧化还原平衡和蛋白质稳定性的影响。这个项目可能会揭示衰老的一个方面的一些机制，即水合作用的丧失。参考文献：El Chami et al . (2011) Experimental Dermatology 23(8) 534-7

Skin provides a barrier between the entire body and the outside world that prevents uncontrolled water loss. Without skin, life as a terrestrial organism would be impossible because water would continually leave the skin to the outside environment. Although the structural components within skin regulating water loss are well characterised, the cellular mechanisms regulating water homeostasis within epidermal skin cells - keratinocytes - have yet to be fully explored.One mechanism by which skin cells control their homeostasis is the transport of organic osmolytes into the cytoplasm in response to water stress. Osmolytes also have other functions besides preservation of water including stabilisation of protein structure and antioxidant effects which are all fundamental to overall cellular health.Dehydration of the skin is common in ageing, leading to xerosis and inflammation. Our hypothesis is that during the process of ageing, the skin loses the ability to either synthesise or transport osmolytes. This may also be true for other less accessible organs as the ability to regulate cell water content is fundamental to all organ systems. In this project, we will characterise the expression and distribution of osmolyte transporters in aged versus young human skin and investigate the effects of specific osmolytes on cell volume control, redox balance and protein stability within keratinocytes cultured from aged and young individuals. This project may shed light on some of the mechanisms underlying one aspect of ageing, i.e. loss of hydration.Reference: El Chami et al (2011) Experimental Dermatology 23(8) 534-7