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Development and Assessment of Intracellular Infection Models for Staphylococcus aureus
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Development and Assessment of Intracellular Infection Models for Staphylococcus aureus

Published on: January 17, 2025

Staphylococcus aureus subvert autophagy for induction of caspase-independent host cell death

Annabelle Schnaith1, Hamid Kashkar, Sonja A Leggio

  • 1Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, 50935 Cologne, Germany.

The Journal of Biological Chemistry
|December 1, 2006
PubMed

Insights

Staphylococcus aureus (S. aureus) invasion triggers host cell autophagy, but the bacteria escape to cause cell death. Autophagy is essential for S. aureus replication and killing, requiring agr-regulated factors.

Area of Science:

  • Microbiology
  • Cell Biology
  • Immunology

Background:

  • Staphylococcus aureus is a significant cause of bacterial infections.
  • S. aureus invades host cells, leading to cell death.
  • The role of autophagy in S. aureus pathogenesis is not fully understood.

Purpose of the Study:

  • To investigate the interaction between S. aureus and host cell autophagy.
  • To determine the role of autophagy in S. aureus replication and host cell death.
  • To identify bacterial factors regulating this interaction.

Main Methods:

  • Invasion assays using HeLa cells and autophagy-deficient mouse embryonic fibroblasts (atg5-/-).
  • Microscopy to observe S. aureus localization within autophagosomes (LC3 co-localization).
  • Analysis of autophagosome maturation (acidification, LAMP-2 acquisition) and bacterial replication.
  • Assessment of host cell death pathways (caspase-independent).
  • Use of S. aureus strains deficient for the agr virulence regulator and treatment with rapamycin.

Main Results:

  • S. aureus rapidly traffics to autophagosomes in HeLa cells.
  • Autophagy-deficient cells prevent S. aureus replication and cell death.
  • S. aureus inhibits autophagosome maturation and lysosome fusion.
  • Bacteria escape autophagosomes to induce caspase-independent cell death.
  • agr-deficient S. aureus strains evade autophagy and are non-cytotoxic.
  • Rapamycin treatment restores replication and cytotoxicity of agr-deficient strains.

Conclusions:

  • Autophagy induction is crucial for S. aureus replication and host cell killing.
  • S. aureus actively manipulates autophagy for its own benefit, including escape and replication.
  • Bacterial factors regulated by agr are essential for autophagy-mediated cytotoxicity.

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