Shiotsu Noriko, Kawamoto Tadafumi, Kawai Mariko, Ikegame Mika, Torii Yasuhiro, Sasaki Hiroyuki, Yamamoto Toshio
Department of Oral Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Comprehensive Dental Clinic, Okayama University Hospital, Okayama, Japan.
Acta Histochem Cytochem. 2017 Aug 25;50(4):119-125. doi: 10.1267/ahc.17006. Epub 2017 Aug 10.
Tight junction (TJ) is one of the cell-cell junctions and known to have the barrier and fence functions between adjacent cells in both simple and stratified epithelia. We examined the distribution pattern, constitutive proteins, and permeability of TJ in the stratified squamous epithelium of the palatal mucosa of mice. Ultrastructural observations based on the ultrathin section and freeze-fracture methods revealed that poorly developed TJs are located at the upper layer of the stratum granulosum. The positive immunofluorescence of occludin (OCD), claudin (CLD)-1 and -4 were localized among the upper layer of the stratum granulosum showing a dot-like distribution pattern. And CLD-1 and -4 were localized among the stratum spinosum and the lower part of stratum granulosum additionally showed a positive reaction along the cell profiles. Western blotting of TJ constitutive proteins showed OCD, CLD-1, -2, -4, and -5 bands. The permeability test using biotin as a tracer revealed both the areas where biotin passed through beyond OCD positive points and the areas where biotin stopped at OCD positive points. These results show that poor TJs localize at the upper layer of the stratum granulosum of the palatal epithelium, and the TJs are leaky and include at least CLD-1 and -4.
紧密连接（TJ）是细胞间连接之一，已知在单层和复层上皮中相邻细胞之间具有屏障和围栏功能。我们研究了小鼠腭黏膜复层鳞状上皮中TJ的分布模式、组成蛋白和通透性。基于超薄切片和冷冻断裂方法的超微结构观察显示，发育不良的TJ位于颗粒层上层。闭合蛋白（OCD）、紧密连接蛋白（CLD）-1和-4的阳性免疫荧光定位于颗粒层上层，呈点状分布模式。此外，CLD-1和-4定位于棘层，颗粒层下部沿细胞轮廓也呈阳性反应。TJ组成蛋白的蛋白质印迹显示有OCD、CLD-1、-2、-4和-5条带。以生物素作为示踪剂的通透性测试显示，生物素通过OCD阳性点以外的区域以及生物素在OCD阳性点处停止的区域。这些结果表明，发育不良的TJ定位于腭上皮颗粒层上层，且TJ有渗漏现象，至少包括CLD-1和-4。
