Groeger S, Jarzina F, Windhorst A, Meyle J
Department of Periodontology, Justus-Liebig-University of Giessen, Giessen, Germany.
Department of Medical Statistics and Informatics, Justus-Liebig-University of Giessen, Giessen, Germany.
J Periodontal Res. 2016 Dec;51(6):748-757. doi: 10.1111/jre.12351. Epub 2016 Feb 1.
The gingival epithelium plays an important role in the protection of oral tissues from microbial challenge. Oral keratinocytes form a barrier and show various cellular contacts, including tight junctions (TJ). To analyse the barrier function in vitro the transepithelial electrical resistance (TER) is commonly used. Retinoic acid (RA) is an important signalling molecule in most tissues, including epithelial differentiation. RA signalling is mediated through three RA receptors. The aim of the study was to investigate the influence of RA on human gingival barriers in vitro.
Immortalized human gingival keratinocytes were seeded on culture plate inserts. The effect of RA with and without infection with Porphyromonas gingivalis W83 on the barrier was analysed by TER measurements. The expression of TJ proteins was investigated by western blot.
During differentiation, mean TER increased from 16 (1 h), 43 (4 h) to 62 (6 h) Ohm × cm . Addition of 15 μm RA increased TER by +19 after 1 h, +25 after 4 h and +16 Ohm × cm after 6 h. The pan-RA receptor inhibitor BMS 493 resulted in TER values comparable to the control. The mean established TER of the control was approximately 110 Ohm × cm . Addition of 15 μm RA elevated TER to 127 Ohm × cm after 1 h, 150 Ohm × cm after 4 h and 189 Ohm × cm after 6 h (p ≤ 0.01). RA plus infection with P. gingivalis W83 further increased the TER increasing effect but could not prevent the destruction of TER induced by bacterial infection. The protein expression of the TJ proteins claudin 4 and occludin was enhanced while ZO-1 was downregulated after 1 h of RA incubation.
RA provides barrier-positive elements to the gingival epithelial cell model that is accompanied by altered expression of TJ proteins.
牙龈上皮在保护口腔组织免受微生物侵害方面发挥着重要作用。口腔角质形成细胞形成一道屏障，并呈现出包括紧密连接（TJ）在内的各种细胞连接。为了在体外分析屏障功能，通常使用跨上皮电阻（TER）。视黄酸（RA）是包括上皮分化在内的大多数组织中的一种重要信号分子。RA信号通过三种RA受体介导。本研究的目的是在体外研究RA对人牙龈屏障的影响。
将永生化的人牙龈角质形成细胞接种在培养板插入物上。通过TER测量分析有或无牙龈卟啉单胞菌W83感染情况下RA对屏障的影响。通过蛋白质印迹法研究TJ蛋白的表达。
在分化过程中，平均TER从16（1小时）、43（4小时）增加到62（6小时）欧姆×厘米。添加15μM RA后，1小时后TER增加19，4小时后增加25，6小时后增加16欧姆×厘米。全RA受体抑制剂BMS 493产生的TER值与对照组相当。对照组的平均稳定TER约为110欧姆×厘米。添加15μM RA后，1小时后TER升高至127欧姆×厘米，4小时后为150欧姆×厘米，6小时后为189欧姆×厘米（p≤0.01）。RA加牙龈卟啉单胞菌W83感染进一步增强了TER增加的效果，但无法阻止细菌感染诱导的TER破坏。RA孵育1小时后，TJ蛋白claudin 4和occludin的蛋白表达增强，而ZO-1下调。
RA为牙龈上皮细胞模型提供了屏障阳性成分，同时伴有TJ蛋白表达的改变。
