Modulation of Lipoteichoic Acids and Exopolysaccharides Prevents Streptococcus mutans Biofilm Accumulation

Midian C Castillo Pedraza,Jaqueline Da Silva Colin,Erick Dante De Oliveira Fratucelli,Sabrina Marcela Ribeiro,Marlise I Klein,Elkin Jahir Florez Salamanca

doi:10.3390/molecules25092232

Midian C Castillo Pedraza, Jaqueline Da Silva Colin + Show 4 more

Open Access

https://doi.org/10.3390/molecules25092232

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Journal: Molecules	Publication Date: May 9, 2020
Citations: 11	License type: CC BY 4.0

Affiliation: Universidade Estadual Paulista (Unesp)

Abstract

Dental caries is a diet–biofilm-dependent disease. Streptococcus mutans contributes to cariogenic biofilms by producing an extracellular matrix rich in exopolysaccharides and acids. The study aimed to determine the effect of topical treatments with compound 1771 (modulates lipoteichoic acid (LTA) metabolism) and myricetin (affects the synthesis of exopolysaccharides) on S. mutans biofilms. In vitro S. mutans UA159 biofilms were grown on saliva-coated hydroxyapatite discs, alternating 0.1% sucrose and 0.5% sucrose plus 1% starch. Twice-daily topical treatments were performed with both agents alone and combined with and without fluoride: compound 1771 (2.6 µg/mL), myricetin (500 µg/mL), 1771 + myricetin, fluoride (250 ppm), 1771 + fluoride, myricetin + fluoride, 1771 + myricetin + fluoride, and vehicle. Biofilms were evaluated via microbiological, biochemical, imaging, and gene expression methods. Compound 1771 alone yielded less viable counts, biomass, exopolysaccharides, and extracellular LTA. Moreover, the combination 1771 + myricetin + fluoride decreased three logs of bacterium counts, 60% biomass, >74% exopolysaccharides, and 20% LTA. The effect of treatments on extracellular DNA was not pronounced. The combination strategy affected the size of microcolonies and exopolysaccharides distribution and inhibited the expression of genes linked to insoluble exopolysaccharides synthesis. Therefore, compound 1771 prevented the accumulation of S. mutans biofilm; however, the effect was more pronounced when it was associated with fluoride and myricetin.

Highlights

Dental caries is a public health problem worldwide affecting humans without distinction of age and is the main factor related to the loss of dentition [1]
As none of the tested concentration for both agents leads to the absence of bacterial growth on agar plates, the minimum bactericidal concentration (MBC) was not determined
Approaches combining bioactive agents with fluoride for preventing cariogenic biofilm Approaches combining bioactive agents with fluoride for preventing cariogenic biofilm development development have been proposed, including compounds that affect the production of an EPS-rich have been proposed, including compounds that affect the production of an EPS-rich matrix [22,37]

Summary

Introduction

Dental caries is a public health problem worldwide affecting humans without distinction of age and is the main factor related to the loss of dentition [1]. Among several species that comprise the oral microbiota, Streptococcus mutans is considered an important etiological factor for dental caries in association with a sugar-rich diet [4,5] The uniqueness of this species is its ability to orchestrate the cariogenic biofilm build-up by producing a three-dimensional (3D) extracellular matrix rich in exopolysaccharides (EPS) that hampers diffusion and creates microenvironments where metabolites such acids accumulate within the biofilm and at the interface biofilm/teeth surface [6], leading to the demineralization of teeth enamel [7].

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