Shi Yumeng, Li Rongqiang, Yang Jin, Li Xinbo
Eye Institute, Eye and Ear, Nose, and Throat Hospital of Fudan University 83 Fenyang Road, Shanghai 200031, People's Republic of China.
Department of Urology, Weihaiwei Hospital Weihai, Shandong, China.
Int J Physiol Pathophysiol Pharmacol. 2020 Apr 15;12(2):70-78. eCollection 2020.
Tight junctions are important structures that form the barrier of cells and tissues, and they play key roles in maintaining homeostasis of our body. The backbone of the tight junction proteins are claudins, which composed more than twenty members. The tight junction protein 1 (TJP1), also called ZO-1 (Zonula Occludens-1), is one of the tight junction related proteins, and it is widely used in literature to label tight junctions. Here we showed that TJP1 (ZO-1) is highly expressed in cancerous HeLa cells, fibroblast cells, HUVEC as well as MDCK cells, while claudin-1 is highly expressed in HUVEC and MDCK cells, but not expressed in HeLa and fibroblast cells. We aimed to investigate whether tight junction is present in HeLa and fibroblast cells. We used transepithelial/transendothelial electrical resistance (TEER) to measure tight junction dynamics in these cells. The results showed that there is no TEERs in HeLa and fibroblast cells, while there is relatively high TEER in HUVEC and MDCK cells. Importantly, the TEER in MDCK cells is dramatically reduced after knockdown of TJP1 (ZO-1). These results suggest that TJP1 (ZO-1) cannot be used as a marker of tight junctions in a variety of cells, while TJP1 (ZO-1) may play an important role in regulation of tight junctions in MDCK cells.
紧密连接是形成细胞和组织屏障的重要结构，它们在维持我们身体的内环境稳定中发挥关键作用。紧密连接蛋白的核心是claudins，其由二十多个成员组成。紧密连接蛋白1（TJP1），也称为ZO-1（闭锁小带-1），是一种紧密连接相关蛋白，在文献中广泛用于标记紧密连接。在这里我们表明，TJP1（ZO-1）在癌性HeLa细胞、成纤维细胞、人脐静脉内皮细胞（HUVEC）以及犬肾上皮细胞（MDCK）中高表达，而claudin-1在HUVEC和MDCK细胞中高表达，但在HeLa细胞和成纤维细胞中不表达。我们旨在研究HeLa细胞和成纤维细胞中是否存在紧密连接。我们使用跨上皮/跨内皮电阻（TEER）来测量这些细胞中的紧密连接动态。结果表明，HeLa细胞和成纤维细胞中没有TEER，而HUVEC和MDCK细胞中有相对较高的TEER。重要的是，TJP1（ZO-1）敲低后MDCK细胞中的TEER显著降低。这些结果表明，TJP1（ZO-1）不能用作多种细胞中紧密连接的标志物，而TJP1（ZO-1）可能在MDCK细胞中紧密连接调节中发挥重要作用。
