Environmental influences on Streptococcus sanguinis membrane vesicle biogenesis

Area of Science:

• Microbiology
• Bacterial Physiology
• Host-Microbe Interactions

Background:

• Membrane vesicles (MVs) are crucial for bacterial cell-cell communication and host interactions.
• The environmental and community influences on MV production, especially in oral commensals like Streptococcus sanguinis, are not well understood.

Purpose of the Study:

• To investigate the impact of environmental and community factors on Streptococcus sanguinis membrane vesicle production.
• To identify molecular mechanisms and vesicle cargo involved in S. sanguinis-host cell communication.

Main Methods:

• Comparative transcriptomic and proteomic analyses of S. sanguinis under different co-culture conditions.
• Analysis of MV production (number and size) in response to various oral bacteria.
• In vitro cell culture assays using gingival epithelial cells to assess immune responses.

Main Results:

• Porphyromonas gingivalis abolished S. sanguinis MV production, while other bacteria had no significant effect.
• Differential gene expression related to the cytoplasmic membrane and peptidoglycan correlated with MV abundance.
• S. sanguinis MVs induced significant expression of pro-inflammatory cytokines (IL-8, TNF-α, IL-1β, Gro-α) in gingival epithelial cells.

Conclusions:

• S. sanguinis MV production is regulated by specific bacterial interactions and environmental cues.
• Bacterial MVs play a significant role in mediating communication between oral bacteria and host epithelial cells, potentially modulating host immune responses.