Effect of Osteopontin on the Initial Adhesion of Dental Bacteria

Abstract

Bacterial biofilms are involved in numerous infections of the human body, including dental caries. While conventional therapy of biofilm diseases aims at eradication and mechanical removal of the biofilms, recent therapeutic approaches target the mechanisms of biofilm formation and bacterial adhesion in particular. The effect of bovine milk osteopontin, a highly phosphorylated whey protein, on adhesion of Streptococcus mitis, Streptococcus sanguinis, and Actinomyces naeslundii, three prominent colonizers in dental biofilms, to saliva-coated surfaces was investigated. While adhesion of A. naeslundii was not affected by osteopontin, a strong, dose-dependent reduction in the number of adhering S. mitis was shown. No difference in bacterial adhesion was observed for caseinoglycomacropeptide, another phosphorylated milk protein. Osteopontin did not affect bacterial viability, but changed bacterial surface hydrophobicity, and may be suggested to prevent the adhesins of S. mitis from interacting with their salivary receptors. The antiadhesive effect of osteopontin may be useful for caries prevention.

Osteopontin adsorption to Gram-positive cells reduces adhesion forces and attachment to surfaces under flow

“…Adhesion of streptococci (S. oralis and S. mitis) was most severely affected, and effects of OPN on these species could be measured at concentrations down to 4.6 µM. This finding corroborates results from a previous study where A. naeslundii was less affected by 26.5 µM of OPN than S. mitis, albeit in a different flow cell system [7]. The difference between the bacterial species can either reflect differences in their affinity for OPN adsorption or differences in how OPN intercepts their specific mode of attachment.…”

“…Previous studies have shown that OPN binds to the cell surface of S. mitis [7], a pioneer colonizer of dental enamel, which is also associated with the development of caries lesions [37][38][39][40][41]. The presence of OPN hampers adhesion of S. mitis to saliva-coated surfaces and diminishes biofilm formation in a multi-species in vitro oral biofilm model dominated by S. mitis [8].…”

“…It was found that the phosphoprotein osteopontin (OPN) from bovine milk interferes with the adhesion of the early dental colonizer Streptococcus mitis to saliva-coated surfaces [7], and that it reduces biofilm formation in a multi-species model biofilm dominated by S. mitis [8]. Milk OPN is an intrinsically disordered protein, with little secondary structure and a high degree of phosphorylation [9].…”

Calcium-Phosphate-Osteopontin Particles Reduce Biofilm Formation and pH Drops in in situ Grown Dental Biofilms

“…Hence, there is a large spectrum of physico-chemical properties and adhesive molecules involved during in vivo biofilm formation, and calciumphosphate-osteopontin particles might only interfere with some of these. We have previously shown that low concentrations of osteopontin (about 1/10 of the concentration in calcium-phosphate-osteopontin particles) efficiently reduce the adhesion of S. mitis to saliva-coated surfaces, but not that of Actinomyces naeslundii [Schlafer et al, 2012a]. Differences in biofilm species composition might therefore account for the observed inter-individual differences, which may limit the use of calcium-phosphate-osteopontin particles as a universal biofilm controlling agent.…”

“…While the main proposed mechanism of CPP-ACP is the provision of calcium and phosphate in solution, which in turn enhances remineralization [Reynolds, 1997], casein, as well as other milk proteins, have been reported to affect bacterial adhesion and retard dental biofilm formation [Guggenheim et al, 1999;Arslan et al, 2009;Danielsson Niemi et al, 2009;Wakabayashi et al, 2009]. To this end, we have previously shown that bovine milk osteopontin, a highly phosphorylated whey protein, reduces bacterial adhesion to salivary-coated surfaces and biofilm formation in a 5-species laboratory model mimicking dental biofilm [Schlafer et al, 2012a, b]. Moreover, we could demonstrate that osteopontin-containing calcium phosphate particles both reduce biofilm formation and increase biofilm pH in the model .…”