IADR Abstract Archives
Biogenesis and Characterization of Extracellular Membrane Vesicles From Streptococcus Sanguinis
Objectives: Streptococcus sanguinis is highly prevalent in the oral cavity and characterized for its ability to inhibit colonization of oral pathogens. Like many other cell types, streptococci produce extracellular membrane vesicles, which contain specific molecular cargo and facilitate interactions with host cells. Our aim is to establish the environmental and community effects that play a role in S. sanguinis vesicle production, and to characterize the effects of vesicles on eukaryotic cells.
Methods: We used differential centrifugation methods with image analysis to isolate and quantify S. sanguinis vesicles. Transcriptomic analyses combined differential expression and correlation of count data with vesicle quantity to examine gene expression changes underlying vesicle production. Proteomic characterization of the vesicle cargo was done via mass spectrometry. To test the immunostimulatory effects, S.sanguinis vesicles were inoculated onto gingival epithelial cells, followed by gene expression analysis.
Results: Vesicle production is dependent on both environmental and community factors; carbohydrates differentially affect vesicle production with about an 80% reduction in vesicle number in cultures supplemented with sucrose as compared to glucose. Co-culture with interacting commensal Cornyebacterium durum, as well as with pathobiont Filifactor alocis had no effect on S. sanguinis vesicle number, whereas pathobiont Porphyromonas gingivalis greatly reduced S. sanguinis vesicle number. Expression of genes encoding proteins localized to the cytoplasmic membrane correlate with the abundance of vesicles. Proteomic characterization of the vesicle cargo identified several proteins predicted to influence host immune responses. Studies of gingival epithelial cells demonstrated that vesicles induced the expression of IL-8, TNF-α, and Gro-α without causing cell death.
Conclusions: S.sanguinis vesicle production is influenced by community and environmental factors, and plays a role in communication with host cells. The immunostimulatory effects of S. sanguinis vesicles highlight an important role in commensalism; in which a microbe induces an immune response but avoids damage to host cells, thus discouraging infection by pathobionts.
Methods: We used differential centrifugation methods with image analysis to isolate and quantify S. sanguinis vesicles. Transcriptomic analyses combined differential expression and correlation of count data with vesicle quantity to examine gene expression changes underlying vesicle production. Proteomic characterization of the vesicle cargo was done via mass spectrometry. To test the immunostimulatory effects, S.sanguinis vesicles were inoculated onto gingival epithelial cells, followed by gene expression analysis.
Results: Vesicle production is dependent on both environmental and community factors; carbohydrates differentially affect vesicle production with about an 80% reduction in vesicle number in cultures supplemented with sucrose as compared to glucose. Co-culture with interacting commensal Cornyebacterium durum, as well as with pathobiont Filifactor alocis had no effect on S. sanguinis vesicle number, whereas pathobiont Porphyromonas gingivalis greatly reduced S. sanguinis vesicle number. Expression of genes encoding proteins localized to the cytoplasmic membrane correlate with the abundance of vesicles. Proteomic characterization of the vesicle cargo identified several proteins predicted to influence host immune responses. Studies of gingival epithelial cells demonstrated that vesicles induced the expression of IL-8, TNF-α, and Gro-α without causing cell death.
Conclusions: S.sanguinis vesicle production is influenced by community and environmental factors, and plays a role in communication with host cells. The immunostimulatory effects of S. sanguinis vesicles highlight an important role in commensalism; in which a microbe induces an immune response but avoids damage to host cells, thus discouraging infection by pathobionts.