Effect of amino sugars metabolism on the extracellular matrix of in vitro oral mixed-species biofilms

Abstract

It is unknown how the amino sugars N-Acetylglucosamine (GlcNAc) and glucosamine (GlcN) influence the extracellular matrix build-up in dental biofilm. It is unknown whether the presence of GlcNAc and GlcN in a sucrose-rich diet (with starch) can minimize the diet's cariogenicity. Sucrose is the main substrate for exoenzymes glucosyltransferases to synthesize exopolysaccharides (glucans), among which the water-insoluble ones are virulence determinants. Aminosugars interfere in the antagonistic properties of Streptococcus gordonii against Streptococcus mutans (hydrogen peroxide production and increase in the arginolític activity - alkali production). S. gordonii metabolizes these substrates better than S. mutans. However, the aminosugars can also promote mutacin production in vitro (that inhibits S. gordonii growth). Thus, there is no consensus on whether these aminosugars could act as prebiotics and prevent the formation of cariogenic biofilms. Therefore, the aim is to evaluate how the presence of aminosugars GlcNAc and GlcN affect the extracellular matrix build-up in a mixed-species dental biofilm grown under a cariogenic diet. To achieve this aim, in vitro mixed-species biofilms of S. mutans, S. gordonii, Actinomyces naeslundii, Streptococcus sanguinis, and Veillonella parvula will be grown on saliva-coated hydroxyapatite discs. Three groups will be evaluated: 1) a control without aminosugar, 2) test with GlcNAc, and 3) test with GlcN. These biofilms will be examined to quantify the microbial population, biomass, extracellular matrix biochemical composition (DNA, lipoteichoic acids, polysaccharides, proteins), the 3D structure, and the creation of microniches. The quantitative data will be analyzed using descriptive and inferential statistics (±=0.05). The changes in the parameters evaluated may explain whether the aminosugars contribute to the prevention of the extracellular matrix construction and, consequently, of the biofilm.