Cui Guxin, Li Pengpeng, Wu Ruixue, Lin Huancai
Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China.
Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China.
AMB Express. 2022 Dec 12;12(1):154. doi: 10.1186/s13568-022-01499-3.
Streptococcus mutans, whose main virulence factor is glucosyltransferase (Gtf), has a substantial impact on the development of dental caries. S. mutans membrane vesicles (MVs), which are rich in Gtfs, have been shown to affect biofilm formation of other microorganisms. Streptococcus gordonii and Streptococcus sanguinis are initial colonizers of tooth surfaces, which provide attachment sites for subsequent microorganisms and are crucial in the development of oral biofilms. S. mutans and S. gordonii, as well as S. mutans and S. sanguinis, have a complex competitive and cooperative relationship, but it is unclear whether S. mutans MVs play a role in these interspecific interactions. Therefore, we co-cultured S. mutans MVs, having or lacking Gtfs, with S. gordonii and S. sanguinis. Our results showed that S. mutans MVs inhibited biofilm formation of S. gordonii and S. sanguinis but did not affect their planktonic growth; contrastingly, S. mutans ΔgtfBC mutant MVs had little effect on both their growth and biofilm formation. Additionally, there were fewer and more dispersed bacteria in the biofilms of the S. mutans MV-treated group than that in the control group. Furthermore, the expression levels of the biofilm-related virulence factors GtfG, GtfP, and SpxB in S. gordonii and S. sanguinis were significantly downregulated in response to S. mutans MVs. In conclusion, the results of our study showed that S. mutans MVs inhibited biofilm formation of S. gordonii and S. sanguinis, revealing an important role for MVs in interspecific interactions.
变形链球菌的主要毒力因子是葡糖基转移酶（Gtf），它对龋齿的发展有重大影响。富含Gtfs的变形链球菌膜泡（MVs）已被证明会影响其他微生物的生物膜形成。戈登链球菌和血链球菌是牙齿表面的初始定植菌，它们为后续微生物提供附着位点，在口腔生物膜的形成中至关重要。变形链球菌与戈登链球菌之间，以及变形链球菌与血链球菌之间，存在复杂的竞争与合作关系，但尚不清楚变形链球菌MVs在这些种间相互作用中是否发挥作用。因此，我们将含有或缺乏Gtfs的变形链球菌MVs与戈登链球菌和血链球菌进行了共培养。我们的结果表明，变形链球菌MVs抑制了戈登链球菌和血链球菌的生物膜形成，但不影响它们的浮游生长；相反，变形链球菌ΔgtfBC突变体MVs对它们的生长和生物膜形成几乎没有影响。此外，与对照组相比，变形链球菌MV处理组生物膜中的细菌数量更少且分布更分散。此外，戈登链球菌和血链球菌中与生物膜相关的毒力因子GtfG、GtfP和SpxB的表达水平在接触变形链球菌MVs后显著下调。总之，我们的研究结果表明，变形链球菌MVs抑制了戈登链球菌和血链球菌的生物膜形成，揭示了MVs在种间相互作用中的重要作用。
