Abstract
As one of the most important cariogenic pathogens, Streptococcus mutans has strong abilities to form biofilms, produce acid and tolerate acid. In present study, we found that theaflavin-3,3′-digallate (TF3) had an inhibitory effect on S. mutans UA159 in vitro. Visualized by field emission-scanning electron microscopy, the suppressed formation of S. mutans biofilms grown with TF3 at sub-inhibitory concentrations could be attributed to the reduced biofilm matrix, which was proven to contain glucans and extracellular DNA (eDNA). Glucan-reduced effect of TF3 was achieved by down-regulating expression levels of gtfB, gtfC, and gtfD encoding glucosyltransferases. Besides, TF3 reduced eDNA formation of S. mutans by negatively regulating lrgA, lrgB, and srtA, which govern cell autolysis and membrane vesicle components. Furthermore, TF3 also played vital roles in antagonizing preformed biofilms of S. mutans. Bactericidal effects of TF3 became significant when its concentrations increased more than twofold of minimum inhibitory concentration (MIC). Moreover, the capacities of S. mutans biofilms to produce acid and tolerate acid were significantly weakened by TF3 at MIC. Based on real-time PCR (RT-PCR) analysis, the mechanistic effects of TF3 were speculated to comprise the inhibition of enolase, lactate dehydrogenase, F-type ATPase and the agmatine deiminase system. Moreover, TF3 has been found to downregulate LytST, VicRK, and ComDE two component systems in S. mutans, which play critical roles in the regulatory network of virulence factors. Our present study found that TF3 could suppress the formation and cariogenic capacities of S. mutans biofilms, which will provide new strategies for anti-caries in the future.
Highlights
Dental caries, a deleterious disease, affects more than 35% of people at all ages globally (Pitts et al, 2017), but effective strategies to prevent and manage this disease are still needed
We found that TF3 strongly protects against the formation and cariogenic ability of S. mutans biofilms
TF3 Exerts the Strongest Antibacterial Effects Among Four Theaflavins To clarify which component of theaflavins drives the antibacterial effects against S. mutans, four main theaflavins (TF1/TF2a/TF2b/TF3) were investigated and minimum inhibitory concentration (MIC) were determined (Supplementary Figure 2)
Summary
A deleterious disease, affects more than 35% of people at all ages globally (Pitts et al, 2017), but effective strategies to prevent and manage this disease are still needed. During the process of biofilm formation, Gtfs secreted by S. mutans bind to the acquired pellicle and surfaces of non-Gtfs producers, which enables glucan production in situ (Schilling and Bowen, 1992; Bowen and Koo, 2011). As another crucial component of EPSs, eDNA interacts with polysaccharides and reinforces biofilms (Klein et al, 2015); it is produced by bacterial cell autolysis and membrane vesicles (MVs) in S. mutans (Perry et al, 2009; Liao et al, 2014). Sortase A (SrtA), a transpeptidase, affects the protein profile of MVs and control eDNA production (Liao et al, 2014)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
