Aggregatibacter actinomycetemcomitans regulates the expression of integrins and reduces cell adhesion via integrin α5 in human gingival epithelial cells
Aggregatibacter actinomycetemcomitans regulates the expression of integrins and reduces cell adhesion via integrin α5 in human gingival epithelial cells
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DOI：
10.1007/s11010-017-3076-z
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发表时间：
2017-12-01
影响因子：
4.3
通讯作者：
Takashiba, Shogo
中科院分区：
文献类型：
--
作者：
Kochi, Shinsuke;Yamashiro, Keisuke;Takashiba, Shogo
牙龈上皮细胞形成抵抗细菌入侵的生理屏障。过多的细菌侵入破坏了牙齿表面和上皮之间的附着，导致牙周炎。整合素在细胞粘附中起着重要作用，因此，我们假设细菌感染可能会降低牙龈上皮细胞中这些整合素的表达，导致细胞粘附减少。将永生化的人牙龈上皮细胞与伴放线菌聚集杆菌Y 4（Aa Y 4）共培养，并使用定量逆转录聚合酶链反应测量IL-8、增殖细胞核抗原（PCNA）和整合素（α 2、α 3、α 5、β 4和β 6）的基因表达水平。在与Aa Y 4共培养的细胞中，PCNA和整合素（除整合素α 5外）的表达显著下调，而IL-8和整合素α 5的表达显著上调。当与Aa Y 4共培养时，粘附细胞的数量显著减少，如使用细胞粘附测定所确定的。在与Aa Y 4和整合素α 5中和抗体共培养的细胞中，对IL-8和PCNA的表达没有影响，而整合素α 2、α 3、β 4和β 6的表达以及粘附细胞的数量没有减少。在抗体存在下，细胞中侵入细菌的数量减少，而在TLR 2/4抑制剂存在下，细胞中侵入细菌的数量增加。因此，整合素α 5可能参与了Aa Y 4侵入牙龈上皮细胞，并且所产生的信号转导级联通过降低整合素的表达来降低细胞粘附，而TLR 2/4信号转导级联调节IL-8的表达。
Gingival epithelial cells form a physiological barrier against bacterial invasion. Excessive bacterial invasion destroys the attachment between the tooth surface and the epithelium, resulting in periodontitis. Integrins play a significant role in cell attachment; therefore, we hypothesized that bacterial infection might decrease the expressions of these integrins in gingival epithelial cells, resulting in reduced cell adhesion. Immortalized human gingival epithelial cells were co-cultured with Aggregatibacter actinomycetemcomitans Y4 (Aa Y4), and the gene expression levels of IL-8, proliferating cell nuclear antigen (PCNA), and integrins (alpha 2, alpha 3, alpha 5, beta 4, and beta 6) were measured using quantitative reverse transcription polymerase chain reaction. Expression of PCNA and integrins, except integrin alpha 5, was significantly downregulated, while expression of IL-8 and integrin alpha 5 was significantly upregulated in the cells co-cultured with Aa Y4. The number of adherent cells significantly decreased when co-cultured with Aa Y4, as determined using cell adhesion assays. In the cells co-cultured with Aa Y4 and an integrin alpha 5 neutralizing antibody, there was no effect on the expression of IL-8 and PCNA, while the expressions of integrins alpha 2, alpha 3, beta 4, and beta 6, and the number of adherent cells did not decrease. The number of invading bacteria in the cells was reduced in the presence of the antibody and increased in the presence of TLR2/4 inhibitor. Therefore, integrin alpha 5 might be involved in Aa Y4 invasion into gingival epithelial cells, and the resulting signal transduction cascade reduces cell adhesion by decreasing the expression of integrins, while the TLR2/4 signaling cascade regulates IL-8 expression.