Project description:The human oral cavity harbors a diverse microbial community, with oral streptococci, particularly the Streptococcus mitis group, playing a pivotal role in biofilm formation and oral health. Among these, Streptococcus oralis is a key early colonizer that stabilizes oral biofilms. Here, we identify two mucin-degrading proteases, MdpS and MdpS2, that enable S. oralis to degrade MUC5B, the sole gel-forming mucin in saliva. Despite low sequence similarity, these enzymes share a high degree of tertiary structural resemblance and exhibits complementary biological functions. Their activity leads to extensive MUC5B degradation influencing biofilm dynamics by promoting biofilm dispersal and altering MUC5B and/or MUC5AC BCi mucus gels properties, with MdpS2 displaying specificity for MUC5B gels. Our findings reveal a specialized role in biofilm structural remodeling, offering potential avenues for clinical applications in biofilm modulation and mucus degradation.
Project description:To combat dental implant-associated infections, there is a need for novel materials which effectively inhibit bacterial biofilm formation. In the present study, a titanium surface functionalization based on the “slippery liquid-infused porous surfaces” (SLIPS) principle was analyzed in an oral flow chamber system. The immobilized liquid layer was stable over 13 days of continuous flow. With increasing flow rates, the surface exhibited a significant reduction in attached biofilm of both the oral initial colonizer Streptococcus oralis and an oral multi-species biofilm composed of S. oralis, Actinomyces naeslundii, Veillonella dispar and Porphyromonas gingivalis. Using single cell force spectroscopy, reduced bacterial adhesion forces on the lubricant layer could be measured. Gene expression patterns in biofilms on SLIPS, on control surfaces and planktonic cultures were also compared. For this purpose, the genome of S. oralis strain ATCC® 9811TM was sequenced using PacBio Sequel technology. Even though biofilm cells showed clear changes in gene expression compared to planktonic cells, no differences could be detected between bacteria on SLIPS and on control surfaces. Therefore, it can be concluded that the ability of liquid-infused titanium to repel biofilms is solely due to weakened bacterial adhesion to the underlying liquid interface.
Project description:Oral biofilms, comprising hundreds of bacteria and other microorganisms on oral mucosal and dental surfaces, play a central role in oral health and disease dynamics. Streptococcus oralis, a key constituent of these biofilms, contribute significantly to their formation, serving as an early colonizer and microcolony scaffold. The interaction between S. oralis and the orally predominant mucin, MUC5B, is pivotal in biofilm development, yet the mechanism underlying MUC5B degradation remains poorly understood. This study introduces MdpS (Mucin Degrading Protease from Streptococcus oralis), a protease that extensively hydrolyses MUC5B and offers an insight into its sequence homology, physicochemical properties, and substrate- and amino acid specificity. MdpS exhibits high sequence conservation within the species and also explicitly among early biofilm colonizing streptococci. It is characterized as a calcium or magnesium dependent serine protease with strict physicochemical preferences, including narrow pH and temperature tolerance, and high sensitivity to increased sodium chloride and reducing agent concentrations. Furthermore, MdpS primarily hydrolyze proteins with O-glycans, but also show activity towards immunoglobulins IgA1/2 and IgM, suggesting potential immunomodulatory effects. Significantly, MdpS extensively degrades MUC5B in the N- and C-terminal domains, emphasizing its role in mucin degradation with implications in carbon and nitrogen sequestration for S. oralis with a potential function by cross-feeding the oral biofilm. Moreover, the enzyme displays amino acid preferences of serine, threonine or cysteine depending on substrate glycosylation. Understanding the interplay between S. oralis and MUC5B, facilitated by MdpS, has significant implications for the management of a healthy eubiotic oral microenvironment, offering potential targets for interventions aimed at modulating oral biofilm composition and succession. Additionally, the MdpS data challenges the presently acknowledged model of MUC5B degradation, because contrarily MdpS does not necessitate O-glycan removal prior to extensive peptide backbone hydrolysis. These findings emphasize the necessity for further research in this field.
Project description:Oral biofilms, comprising hundreds of bacteria and other microorganisms on oral mucosal and dental surfaces, play a central role in oral health and disease dynamics. Streptococcus oralis, a key constituent of these biofilms, contribute significantly to their formation, serving as an early colonizer and microcolony scaffold. The interaction between S. oralis and the orally predominant mucin, MUC5B, is pivotal in biofilm development, yet the mechanism underlying MUC5B degradation remains poorly understood. This study introduces MdpS (Mucin Degrading Protease from Streptococcus oralis), a protease that extensively hydrolyses MUC5B and offers an insight into its sequence homology, physicochemical properties, and substrate- and amino acid specificity. MdpS exhibits high sequence conservation within the species and also explicitly among early biofilm colonizing streptococci. It is characterized as a calcium or magnesium dependent serine protease with strict physicochemical preferences, including narrow pH and temperature tolerance, and high sensitivity to increased sodium chloride and reducing agent concentrations. Furthermore, MdpS primarily hydrolyze proteins with O-glycans, but also show activity towards immunoglobulins IgA1/2 and IgM, suggesting potential immunomodulatory effects. Significantly, MdpS extensively degrades MUC5B in the N- and C-terminal domains, emphasizing its role in mucin degradation with implications in carbon and nitrogen sequestration for S. oralis with a potential function by cross-feeding the oral biofilm. Moreover, the enzyme displays amino acid preferences of serine, threonine or cysteine depending on substrate glycosylation. Understanding the interplay between S. oralis and MUC5B, facilitated by MdpS, has significant implications for the management of a healthy eubiotic oral microenvironment, offering potential targets for interventions aimed at modulating oral biofilm composition and succession. Additionally, the MdpS data challenges the presently acknowledged model of MUC5B degradation, because contrarily MdpS does not necessitate O-glycan removal prior to extensive peptide backbone hydrolysis. These findings emphasize the necessity for further research in this field.
2024-02-14 | PXD046954 | Pride
Project description:In vitro biofilm growth of human oral biofilm
| PRJNA1021815 | ENA
Project description:Lectin staining of oral biofilm
| PRJNA833942 | ENA
Project description:Transcriptomic analysis of oral biofilm
Project description:<p>Bacterial metabolism in oral biofilms is comprised of complex networks of nutritional chains and biochemical regulations. These processes involve both intraspecies and interspecies networks as well as interactions with components from host saliva, gingival crevicular fluid, and dietary intake. In a previous paper, a large salivary glycoprotein, mucin MUC5B, was suggested to promote a dental health-related phenotype in the oral type strain of <em>Streptococcus gordonii</em> DL1, by regulating bacterial adhesion and protein expression. In this study, nuclear magnetic resonance-based metabolomics was used to examine the effects on the metabolic output of monospecies compared to dual species early biofilms of two clinical strains of oral commensal bacteria, <em>S. gordonii</em> and <em>Actinomyces naeslundii</em>, in the presence of MUC5B. The presence of <em>S. gordonii</em> increased colonization of <em>A. naeslundii</em> on salivary MUC5B, and both commensals were able to utilize MUC5B as a sole nutrient source during early biofilm formation. The metabolomes suggested that the bacteria were able to release mucin carbohydrates from oligosaccharide side chains as well as amino acids from the protein core. Synergistic effects were also seen in the dual species biofilm metabolome compared to the monospecies, indicating that <em>A. naeslundii</em> and <em>S. gordonii</em> cooperated in the degradation of salivary MUC5B. A better understanding of bacterial interactions and salivary-mediated regulation of early dental biofilm activity is meaningful for understanding oral biofilm physiology and may contribute to the development of future prevention strategies for biofilm-induced oral disease.</p>
Project description:The oral cavity is considered an extra-gastric reservoir for Helicobacter pylori (H. pylori) and oral H. pylori can contribute to the gastric eradication inability and recurrence. However, the oral environment is not ideal for H. pylori survival, and the factors promoting oral colonization and survival of H. pylori have not been elucidated. In this study, we explored the effects of extracellular polysaccharides (EPS), the fundamental building blocks of dental Streptococcus mutans (S. mutans) biofilm, on H. pylori colonization and drug resistance in the oral cavity, as well as stomach. In the co-culture system of H. pylori Sydney strain (SS1) and three S. mutans biofilms with different EPS contents (UA159 wild-type, UA159ΔgtfB, UA159ΔgtfBC), it was found that the adhesive force between SS1 and biofilms increased correspondingly with the increase in EPS content. Moreover, with the increase in EPS content of biofilms, the number of colonized SS1 increased. Proteome analysis revealed that SS1 co-cultured with UA159 biofilm exhibited 149 differentially expressed proteins compared to that co-cultured with UA159ΔgtfB biofilm, with significant enrichment in β-lactamase activity pathway. SS1 co-cultured with UA159 biofilm exhibited 154 differentially expressed proteins compared to that co-cultured with UA159ΔgtfBC biofilm, with significant enrichment in β-lactamase activity, aminoglycoside nucleotidyltransferase activity and antioxidant activity pathways. Both in vivo and in vitro, EPS synthesized by glucosyltransferases (Gtfs) surrounding SS1 was verified to protect SS1 against β-lactam and aminoglycoside antibiotics. These findings demonstrated that S. mutans biofilms mediate oral adhesion, colonization, and antibiotic resistance of H. pylori through a Gtfs-driven EPS biosynthesis mechanism.