IADR Abstract Archives

Effects of Small Molecule on Streptococcus Mutans Biofilm Formation and Virulence Gene Expression

Objectives: Streptococcus mutans is a causative agent of dental caries. Small molecules targeting S. mutans biofilms would benefit in the treatment of dental caries. Thus, the aim of this study is to identify small molecules that inhibit S. mutans biofilm formation.
Methods: Computational technology was utilized for screening compounds. Biomass of S. mutans biofilms were measured with selected compound added by crystal staining violet. Two most potent compound were then compared for their inhibitory effects on biofilm formation, bactericidal effects on planktonic organisms and cytotoxicity to human gingival epithelial cells, herein, more effective compound was applied for further investigation. Then the morphological changes of S. mutans biofilms in the presence or absence of small molecule were recorded by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Finally, quantitative reverse transcriptase PCR (qRT-PCR) was used to evaluate the expression of virulence related genes.
Results: D20 and D25 were selected from the preliminary screening as the two most potent compounds. D25 had stronger inhibitory effects and lower cytotoxicity than D20. Besides, D25 were not bactericidal against S. mutans cells. Thus, D25 were used for further experiments. Based on CLSM images, we could find the decrease of S. mutans biofilm when treated with D25. For SEM images, cluster-like architecture was obvious in D25 group, in addition, the inner structure of big clusters were the same as it shown in control group. The morphology of single cell was recorded by AFM, and no destructive structure were found with D25 added. For expression level of virulence related genes, srtA, pacR, liaR, comDE, vicR, atpD and brpA gene was upregulated while ldh and relA gene was downregulated.
Conclusions: In summary, our study demonstrated that D25 would be a promising small molecule as anti-biofilm agents. Possible mechanism still need further investigation.

2021 South East Asian Division Meeting (Hong Kong)
Hong Kong
2021
086
Cariology Research-Microbiological Studies/Biofilm
  • Chen, Yuanyuan  ( Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University , Guangzhou , China )
  • Lin, Huan-cai  ( Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University , Guangzhou , China )
  • none
    National Natural Science Foundation of China (81570967)
    Poster Session
    Oral microbiome, microbiology and immunology II
    Thursday, 12/09/2021 , 12:00PM - 01:00PM