Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, Hunan 410013, P.R. China.
Institute of Chinese Materia Medica, Hunan Academy of Chinese Medicine, Yuehua Road, Changsha, Hunan 410013, P.R. China.
Int J Biol Sci. 2021 Jan 31;17(3):712-727. doi: 10.7150/ijbs.45885. eCollection 2021.
Tight junction (TJ) is a "zippering up" junction structure located at the uppermost portion of adjacent epithelial/endothelial cells in organs and tissues. TJs maintain the relative stability of intracellular substances and functions by closing or opening intercellular pathways, coordinating the entry and exit of molecules of different sizes and charges, and regulating the permeability of paracellular barrier. TJs also prevent microbial invasion, maintain epithelial/endothelial cell polarity, and regulate cell proliferation. TJs are widely present in the skin and mucosal epithelial barriers, intestinal epithelial barrier, glomerular filtration barrier, bladder epithelial barrier, blood-brain barrier, brain-blood tumor barrier, and blood-testis barrier. TJ dysfunction in different organs can lead to a variety of diseases. In addition to signal pathways, transcription factors, DNA methylation, histone modification, TJ proteins can also be regulated by a variety of non-coding RNAs, such as micro-RNAs, long-noncoding RNAs, and circular RNAs, directly or indirectly. This review summarizes the structure of TJs and introduces the functions and regulatory mechanisms of TJs in different organs and tissues. The roles and mechanisms of non-coding RNAs in the regulation of TJs are also highlighted in this review.
紧密连接（TJ）是一种位于器官和组织中相邻上皮/内皮细胞最上部的“拉链”连接结构。TJ 通过关闭或打开细胞间途径，协调不同大小和电荷分子的进入和退出，调节细胞旁屏障的通透性，从而维持细胞内物质和功能的相对稳定。TJ 还可以防止微生物入侵，维持上皮/内皮细胞极性，并调节细胞增殖。TJ 广泛存在于皮肤和黏膜上皮屏障、肠道上皮屏障、肾小球滤过屏障、膀胱上皮屏障、血脑屏障、脑血肿瘤屏障和血睾屏障中。不同器官的 TJ 功能障碍可导致多种疾病。除了信号通路、转录因子、DNA 甲基化、组蛋白修饰外，TJ 蛋白还可以被多种非编码 RNA（如 micro-RNAs、长非编码 RNA 和环状 RNA）直接或间接调节。本文总结了 TJ 的结构，并介绍了 TJ 在不同器官和组织中的功能和调节机制。本文还强调了非编码 RNA 在调节 TJ 中的作用和机制。
