Zonula occludens-1 demonstrates a unique appearance in buccal mucosa over several layers
Zonula occludens-1 demonstrates a unique appearance in buccal mucosa over several layers
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DOI：
10.1007/s00441-021-03425-8
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发表时间：
2021-02-26
影响因子：
3.6
通讯作者：
Iwata, Hiroaki
中科院分区：
文献类型：
--
作者：
Imafuku, Keisuke;Kamaguchi, Mayumi;Iwata, Hiroaki
紧密连接 (TJ) 牢固地密封上皮细胞，是上皮屏障的关键角色。 TJ 由多种蛋白质组成，包括跨膜紧密蛋白家族和支架闭合小带 (ZO) 家族的蛋白质。上皮组织暴露在不同的条件下：皮肤复层上皮中的空气和肠道单层中的液体。口腔粘膜复层上皮中的 TJ 对于正常颊粘膜中 TJ 蛋白的分布、外观和屏障功能尚未得到充分阐明。我们对这些进行了研究，发现 ZO-1 和 Claudin-1 在粘膜上皮的顶部三分之一和底部四分之三中表达。发现颊粘膜中的ZO-1具有不规则的线性外观。 ZO-1在颊粘膜中连续存在数层。电子显微镜显示颊粘膜有接吻点。在旨在研究内外屏障功能的生物素渗透测定中，生物素示踪剂渗透了几个 ZO-1 层，但并未穿过所有 ZO-1 层。我们发现口腔粘膜细胞敲低 TJP1 或 CLDN1 导致 TER 减少，但 FITC-葡聚糖渗漏没有显着变化。我们的结果表明，ZO-1 在颊粘膜中的分布和外观与皮肤中的不同。我们无法在本研究中证明屏障功能，但我们确实显示了体内针对小分子和体外针对离子的屏障功能。
Tight junctions (TJs) firmly seal epithelial cells and are key players in the epithelial barrier. TJs consist of several proteins, including those of the transmembrane claudin family and the scaffold zonula occludens (ZO) family. Epithelial tissues are exposed to different conditions: to air in the stratified epithelium of the skin and to liquids in the monolayer of the intestine. The TJs in stratified oral mucosal epithelium have remained insufficiently elucidated in terms of distributions, appearances and barrier functions of TJ proteins in normal buccal mucosa. We investigated these and ZO-1 and claudin-1 were found to be expressed in the top third and in the bottom three quarters of the mucosal epithelium. ZO-1 in the buccal mucosa was found to have an irregular linear appearance. ZO-1 in the buccal mucosa continuously existed in several layers. Electron microscopy revealed the buccal mucosa to have kissing points. In a biotin permeation assay that sought to investigate inside-outside barrier function, the biotin tracer penetrated several ZO-1 layers but did not pass through all the ZO-1 layers. We found that the oral mucosal cell knockdown of TJP1 or CLDN1 resulted in decreases of TER but no significant change in FITC-dextran leakage. Our results suggest that the distribution and appearance of ZO-1 in the buccal mucosa differ from those in the skin. We were unable to prove barrier function in this study but we did show barrier function against small molecules in vivo and against ions in vitro.