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Updated: Jun 14, 2025
Legionella pneumophila Outer Membrane Vesicles: Isolation and Analysis of Their Pro-inflammatory Potential on Macrophages
Published on: February 22, 2017
Proinflammatory Effect of Membrane Vesicles Derived from Enterococcus faecalis at Neutral and Alkaline pH
Chenguang Niu1, Jing Huang1, Lifan Wei2
1Department of Endodontics and Operative Dentistry, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, National Center for Stomatology, National Clinical Research Center for Oral Disease, Shanghai Key Laboratory of Stomatology, Shanghai Research Institute of Stomatology, Shanghai, China.
Enterococcus faecalis membrane vesicles (MVs) promote inflammation. MVs derived from alkaline conditions show a stronger proinflammatory effect in vitro and in vivo.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Enterococcus faecalis membrane vesicles (MVs) are implicated in various biological processes.
- The impact of MVs derived from different pH conditions on inflammation is not fully understood.
Purpose of the Study:
- To investigate the proinflammatory effects of Enterococcus faecalis membrane vesicles (MVs) produced at neutral (pH 7.4) and alkaline (pH 9.0) conditions.
- To characterize the protein content of E. faecalis MVs and their influence on inflammatory responses in vitro and in vivo.
Main Methods:
- E. faecalis MVs were isolated and purified.
- Proteomic analysis identified MV protein components.
- THP-1 macrophages were stimulated with MVs to assess inflammatory cytokine and protein expression.
- In vivo studies involved mouse serum cytokine analysis and spleen cell immunophenotyping following MV injection.
Main Results:
- Proteomic analysis revealed significant differences in protein composition between MVs from neutral and alkaline conditions.
- E. faecalis MVs induced concentration-dependent secretion of IL-1β, IL-6, and TNF-α.
- MV exposure increased pro-IL-1β, NF-κBp65, and TLR2 expression.
- In vivo, MVs promoted IL-1β secretion and spleen cell activation, with alkaline-derived MVs showing enhanced effects.
Conclusions:
- Enterococcus faecalis MVs contain virulence-associated proteins and can induce inflammation both in vitro and in vivo.
- MVs derived from alkaline culture conditions exhibit a more potent proinflammatory capacity.
