Department of Pharmacy, G. d'Annunzio" University, Chieti-Pescara, Italy.
Department of Medicine and Ageing Sciences, "G. d'Annunzio" University, Chieti-Pescara, Italy.
J Mater Sci Mater Med. 2018 Mar 19;29(4):36. doi: 10.1007/s10856-018-6040-x.
The molecular mechanisms leading to Streptococcus mitis capability of entering oral cells were investigated in a co-culture of S. mitis and Human Gingival Fibroblasts (HGFs) in the presence of saliva. An innovative colloidal solution based on silver nanoparticles (Chitlac-nAg), a promising device for daily oral care, was added to the experimental system in order to study the effects of silver on the bacterial overgrowth and ability to enter non-phagocytic eukaryotic cells. The entry of bacteria into the eukaryotic cells is mediated by a signalling pathway involving FAK, integrin β1, and the two cytoskeleton proteins vinculin and F-actin, and down-regulated by the presence of saliva both at 3 and 48 h of culture, whereas Chitlac-n Ag exposure seems to influence, by incrementing it, the number of bacteria entering the fibroblasts only at 48 h. The formation of fibrillary extrusion from HGFs and the co-localization of bacteria and silver nanoparticles within the fibroblast vacuoles were also recorded. After longer experimental times (72 and 96 h), the number of S. mitis chains inside gingival cells is reduced, mainly in presence of saliva. The results suggest an escape of bacteria from fibroblasts to restore the microbial balance of the oral cavity.
研究了在唾液存在的情况下，口腔链球菌与人类牙龈成纤维细胞（HGFs）共培养时进入口腔细胞的分子机制。为了研究银对细菌过度生长和进入非吞噬性真核细胞的能力的影响，在实验系统中添加了基于银纳米粒子的创新胶体溶液（Chitlac-nAg），这是一种有前途的日常口腔护理设备。细菌进入真核细胞是由涉及 FAK、整合素 β1 以及两个细胞骨架蛋白 vinculin 和 F-actin 的信号通路介导的，在培养 3 和 48 小时时，唾液的存在会下调该过程，而 Chitlac-nAg 暴露似乎通过增加它来影响仅在 48 小时时进入成纤维细胞的细菌数量。还记录了 HGFs 中纤维状挤出物的形成以及细菌和银纳米粒子在成纤维细胞空泡内的共定位。在更长的实验时间（72 和 96 小时）后，牙龈细胞内链球菌的数量减少，主要是在唾液存在的情况下。结果表明，细菌从成纤维细胞中逃逸以恢复口腔微生物平衡。
