Clostridioides difficile-Derived Extracellular Vesicles Induce Proinflammatory Responses in Macrophages

Area of Science:

• Microbiology
• Immunology
• Cell Biology

Background:

• Clostridioides difficile (CD) causes significant antibiotic-associated diarrhea.
• Extracellular vesicles (EVs) are implicated in pathogen-host interactions.

Purpose of the Study:

• To investigate the role of Clostridioides difficile strain 630-derived EVs (CD630-EVs) in modulating macrophage pro-inflammatory cytokine production.
• To identify key proteins within CD630-EVs responsible for immune modulation.

Main Methods:

• Proteomic analysis of CD630-EVs.
• In vitro stimulation of mouse macrophages with CD630-EVs.
• Measurement of cytokine production (IL-6, MCP-1, IL-1α, TNF-α).
• Inhibition studies using a flagellin receptor inhibitor (TH1020) and protein docking analysis.

Main Results:

• CD630-EVs contain 1064 proteins, including immune-related proteins FliC, TrxA, TrxA2, and HtpG, with FliC being highly expressed.
• CD630-EVs significantly increased pro-inflammatory cytokine production in macrophages.
• TH1020 inhibited cytokine production by disrupting the FliC-TLR5 interaction.
• FliC appears to be a key mediator of CD630-EV-induced inflammation via TLR5 activation.

Conclusions:

• CD630-EVs modulate macrophage inflammatory responses during Clostridioides difficile infection (CDI).
• FliC within CD630-EVs is a critical mediator of inflammation, potentially through TLR5 interaction.
• FliC represents a potential therapeutic target for mitigating intestinal mucosal injury in CDI.