Department of Periodontology, Showa University School of Dentistry, Ohta-ku, Tokyo, Japan.
J Periodontal Res. 2013 Apr;48(2):235-42. doi: 10.1111/jre.12000. Epub 2012 Sep 7.
Gingival epithelium protects against bacterial infection by producing antimicrobial peptides such as calprotectin. Calprotectin consists of proteins S100A8 and S100A9. Although in vitro assay has shown that neutrophils and gingival epithelial cells express calprotectin, the expression of S100A8 and S100A9 and colocalization of both S100 proteins in gingival tissue in vivo are not fully understood. The aim of this study was to investigate the distribution of S100A8 and S100A9 expression in gingival epithelium of mice in the presence and absence of infection.
A quantitative analysis of S100A8 and S100A9 mRNA in junctional epithelium (JE) and oral gingival epithelium (OGE) of both germ-free mice and conventional mice was performed using laser microdissection and real-time polymerase chain reaction (PCR). Confirmation of S100A8 and S100A9 mRNA expression in the JE was conducted by fluorescent immunohistochemistry.
Real-time PCR analysis indicated that S100A8 and S100A9 expressions were mainly detected in JE and only slightly or not detected in OGE. Levels of both S100A8 and S100A9 mRNA expression in JE of conventional mice were significantly higher than those in JE of germ-free mice. Additionally, fluorescent immunohistochemistry showed that S100A8 expression was observed in the JE of both conventional and germ-free mice, whereas S100A9 was expressed in the JE of conventional but not germ-free mice.
S100A8 protein is expressed in JE cells of mice in the presence and in the absence of infection with oral bacteria. S100A9 expression in JE cells in the presence of microflora is significantly increased compared with the absence of microflora, which suggests that S100A9 expression may be induced by infection of microflora. The production of calprotectin in gingival epithelial cells may be mediated through S100A9 induction by bacterial infection.
牙龈上皮通过产生抗菌肽（如钙卫蛋白）来抵御细菌感染。钙卫蛋白由 S100A8 和 S100A9 蛋白组成。虽然体外试验表明中性粒细胞和牙龈上皮细胞表达钙卫蛋白，但体内牙龈组织中 S100A8 和 S100A9 的表达及其两者的共定位尚不完全清楚。本研究旨在探讨在感染存在或不存在的情况下，小鼠牙龈上皮中 S100A8 和 S100A9 表达的分布。
使用激光微切割和实时聚合酶链反应（PCR）对无菌和常规小鼠的结合上皮（JE）和口腔牙龈上皮（OGE）中 S100A8 和 S100A9 mRNA 的定量分析。通过荧光免疫组织化学法对 JE 中 S100A8 和 S100A9 mRNA 的表达进行了确认。
实时 PCR 分析表明，S100A8 和 S100A9 表达主要在 JE 中检测到，在 OGE 中仅少量或未检测到。常规小鼠 JE 中 S100A8 和 S100A9 mRNA 的表达水平明显高于无菌小鼠 JE 中的表达水平。此外，荧光免疫组织化学显示，常规和无菌小鼠的 JE 中均有 S100A8 的表达，而 S100A9 仅在常规小鼠的 JE 中表达，而在无菌小鼠中则不表达。
在存在和不存在口腔细菌感染的情况下，S100A8 蛋白均在小鼠的 JE 细胞中表达。在有微生物存在的情况下，JE 细胞中 S100A9 的表达明显高于无微生物存在的情况下，这表明 S100A9 的表达可能是由微生物感染诱导的。牙龈上皮细胞中钙卫蛋白的产生可能是通过细菌感染诱导 S100A9 表达来介导的。
