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Depletion and Reconstitution of Macrophages in Mice
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Extracellular vesicles of Bacteroides uniformis induce M1 macrophage polarization and aggravate gut inflammation

Wenjie Tang1, Zhixiang Ni1, Yusen Wei1

  • 1College of Animal Science, Zhejiang University, The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, China.

Mucosal Immunology
|May 22, 2024
PubMed

Insights

Weaning triggers gut inflammation. Bacteroides uniformis extracellular vesicles (BEVs) promote this by polarizing macrophages to a pro-inflammatory state, worsening gut health during weaning.

Area of Science:

  • Microbiology
  • Immunology
  • Gastroenterology

Background:

  • Weaning causes gut inflammation and microbial imbalance.
  • The role of gut bacteria and extracellular vesicles in weaning-associated gut inflammation is unclear.

Purpose of the Study:

  • To investigate the link between gut inflammation and macrophage responses during piglet weaning.
  • To explore the impact of Bacteroides uniformis-derived extracellular vesicles (BEVs) on gut inflammation and macrophage polarization.

Main Methods:

  • Single-cell transcriptomic analysis in piglets.
  • Analysis of bacterial distribution in the gastrointestinal tract.
  • Murine colitis model and in vitro macrophage assays using BEVs.

Main Results:

  • Bacteroides uniformis was found to enrich during piglet weaning.
  • BEVs exacerbated gut inflammation in mice and promoted pro-inflammatory macrophage polarization.
  • BEVs suppressed the GM-CSF/STAT5/Arg1 pathway in macrophages, driving M1-like polarization.

Conclusions:

  • BEVs contribute to gut inflammation during weaning by promoting pro-inflammatory macrophage polarization.
  • Bacteroides uniformis and its extracellular vesicles are implicated in weaning-associated gut inflammation.

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