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High-throughput Assay to Phenotype Salmonella enterica Typhimurium Association, Invasion, and Replication in Macrophages
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JAK-ing into M1/M2 Polarization SteErs Salmonella-Containing Macrophages Away from Immune Attack to Promote Bacterial

Igor E Brodsky1

  • 1University of Pennsylvania School of Veterinary Medicine, Department of Pathobiology, Philadelphia, PA 19104, USA; University of Pennsylvania Perelman School of Medicine, Institute for Immunology, Philadelphia, PA 19104, USA.

Cell Host & Microbe
|January 18, 2020
PubMed

Insights

Salmonella infection rewires macrophage polarization to resist TNF-mediated clearance. This research clarifies granuloma formation mechanisms, offering insights into chronic pathogen restriction strategies.

Area of Science:

  • Immunology
  • Microbiology
  • Cell Biology

Background:

  • Granuloma formation is crucial for restricting chronic pathogens, but its molecular underpinnings are not fully understood.
  • Macrophages play a central role in granulomas, with distinct M1 and M2 subtypes influencing disease outcomes.
  • Tumor necrosis factor (TNF) is a key mediator of anti-pathogen immunity, yet some pathogens resist TNF-mediated clearance.

Purpose of the Study:

  • To elucidate the molecular mechanisms by which Salmonella manipulates macrophage polarization during infection.
  • To investigate how Salmonella influences the balance between M1 and M2 macrophages within granulomas.
  • To understand how Salmonella evades TNF-mediated clearance.

Main Methods:

  • Macrophage polarization assays
  • In vivo Salmonella infection models
  • Genetic manipulation of Salmonella and host factors
  • Analysis of cytokine profiles and cell surface markers

Main Results:

  • Salmonella actively rewires macrophage polarization, shifting the balance towards M2-like phenotypes.
  • This reprogramming enhances Salmonella's ability to resist TNF-mediated killing.
  • Specific Salmonella factors were identified that mediate this macrophage polarization shift.

Conclusions:

  • Salmonella's manipulation of macrophage polarization is a key survival strategy.
  • Understanding these mechanisms provides insights into host-pathogen interactions and granuloma dynamics.
  • Targeting macrophage polarization could offer new therapeutic avenues for chronic Salmonella infections.

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