Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
Division of Nephrology and Hypertension, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA.
Int J Mol Sci. 2019 Jul 17;20(14):3513. doi: 10.3390/ijms20143513.
Epithelia act as a barrier to the external environment. The extracellular environment constantly changes, and the epithelia are required to regulate their function in accordance with the changes in the environment. It has been reported that a difference of the environment between the apical and basal sides of epithelia such as osmolality and hydrostatic pressure affects various epithelial functions including transepithelial transport, cytoskeleton, and cell proliferation. In this paper, we review the regulation of epithelial functions by the gradients of osmolality and hydrostatic pressure. We also examine the significance of this regulation in pathological conditions especially focusing on the role of the hydrostatic pressure gradient in the pathogenesis of carcinomas. Furthermore, we discuss the mechanism by which epithelia sense the osmotic and hydrostatic pressure gradients and the possible role of the tight junction as a sensor of the extracellular environment to regulate epithelial functions.
上皮组织作为对外界环境的屏障。细胞外环境不断变化，上皮组织需要根据环境变化来调节其功能。据报道，上皮组织的顶端和基底侧之间的环境差异，如渗透压和静水压力，会影响各种上皮功能，包括跨上皮转运、细胞骨架和细胞增殖。本文综述了渗透压和静水压力梯度对上皮功能的调节作用。我们还研究了这种调节在病理条件下的意义，特别是聚焦于静水压力梯度在癌发病机制中的作用。此外，我们讨论了上皮组织感知渗透和静水压力梯度的机制，以及紧密连接作为细胞外环境传感器调节上皮功能的可能作用。
