IADR Abstract Archives
Royal Jelly Exosomes: a Novel Potential Strategy Against Oral Biofilms
Objectives: Honeybee Apis mellifera Royal Jelly is known to be antibacterial and pro-regenerative, and has been shown exert beneficial effects for several oral conditions (e.g. mucositis). However, the mechanisms underlying these effects remain unknown. Recently, it has been shown that royal jelly contains exosome-like vesicles (ELV) with strong antibacterial and biofilm inhibiting effects against Staphylococcus aureus. The aim of our study was to analyze the antibacterial and biofilm-inhibiting effects of royal jelly ELVs (RJ-ELVs) on relevant oral bacteria strains. Furthermore, to analyze RJ-ELV cargo potentially involved in the proposed effects.
Methods: RJ-ELVs were isolated by ultracentrifugation and analyzed concerning their size distribution using Nanoparticle Tracking Analysis (NTA). Streptococcus mutans ATCC-UA159 and Streptococcus sanguinis ATCC-SK36 were chosen to assess antibiotic and biofilm-inhibiting effects. Both strains were cultivated and adjusted to 0.5 McFarland, and subsequently incubated with different concentrations of RJ-ELVs (0.1:1, 1:1, 10:1, 100:1 RJ-ELVs per CFU) in a microplate biofilm assay. Growth behavior, MIC (minimal inhibitory concentration) and MBC (minimal bactericidal concentration) as well as biofilm inhibition were assessed. RJELV cargo was analyzed using Western Blot.
Results: Transmission Electron Microscopy confirmed the presence of ELVs. NTA revealed that the mean size of RJ-ELVs was 130nm and median 120nm. It was found that for both streptococcus strains concentrations of 1:1 RJ-ELV to CFU are sufficient to exert growth- and biofilm inhibition. Major Royal Jelly Protein 1 (MRJP1) and Defensin 1, both known antibacterial compounds, could be identified as cargo of RJ-ELVs.
Conclusions: This is the first study reporting antimicrobial effects of RJ-ELVs in oral bacteria and identifying at least two cargo proteins involved. Being protected by ELV, these proteins are less prone to degradation. With RJ-ELVs also displaying the advantages of being easily accessible and from a cost-effective source, we propose RJ-ELVs as a promising novel strategy for biofilm control in the oral cavity
Methods: RJ-ELVs were isolated by ultracentrifugation and analyzed concerning their size distribution using Nanoparticle Tracking Analysis (NTA). Streptococcus mutans ATCC-UA159 and Streptococcus sanguinis ATCC-SK36 were chosen to assess antibiotic and biofilm-inhibiting effects. Both strains were cultivated and adjusted to 0.5 McFarland, and subsequently incubated with different concentrations of RJ-ELVs (0.1:1, 1:1, 10:1, 100:1 RJ-ELVs per CFU) in a microplate biofilm assay. Growth behavior, MIC (minimal inhibitory concentration) and MBC (minimal bactericidal concentration) as well as biofilm inhibition were assessed. RJELV cargo was analyzed using Western Blot.
Results: Transmission Electron Microscopy confirmed the presence of ELVs. NTA revealed that the mean size of RJ-ELVs was 130nm and median 120nm. It was found that for both streptococcus strains concentrations of 1:1 RJ-ELV to CFU are sufficient to exert growth- and biofilm inhibition. Major Royal Jelly Protein 1 (MRJP1) and Defensin 1, both known antibacterial compounds, could be identified as cargo of RJ-ELVs.
Conclusions: This is the first study reporting antimicrobial effects of RJ-ELVs in oral bacteria and identifying at least two cargo proteins involved. Being protected by ELV, these proteins are less prone to degradation. With RJ-ELVs also displaying the advantages of being easily accessible and from a cost-effective source, we propose RJ-ELVs as a promising novel strategy for biofilm control in the oral cavity