Avoiding death by autophagy: interactions of Listeria monocytogenes with the macrophage autophagy system

Autophagy. 2008 Apr;4(3):368-71. doi: 10.4161/auto.5594. Epub 2008 Jan 17.

Abstract

Autophagy restricts the growth of a variety of intracellular pathogens. However, cytosol-adapted pathogens have evolved ways to evade restriction by this innate immune mechanism. Listeria monocytogenes is a Gram-positive bacterial pathogen that utilizes a cholesterol-dependent pore-forming toxin, listeriolysin O (LLO), to escape from the phagosome. Autophagy targets L. monocytogenes in LLO-damaged phagosomes and also in the cytosol under some experimental conditions. However, this bacterium has evolved multiple mechanisms to evade restriction by autophagy, including actin-based motility in the cytosol and an as yet undefined mechanism mediated by bacterial phospholipases C (PLCs). A population of L. monocytogenes with inefficient LLO activity forms Spacious Listeria-containing Phagosomes (SLAPs), which are autophagosome-like compartments that do not mature, allowing slow bacterial growth within enlarged vesicles. SLAPs may represent a stalemate between bacterial LLO action and the host autophagy system, resulting in persistent infection.

MeSH terms

  • Actins / physiology
  • Animals
  • Autophagy / physiology*
  • Bacterial Proteins / physiology
  • Bacterial Toxins
  • Cytosol / physiology
  • Heat-Shock Proteins / physiology
  • Hemolysin Proteins / physiology
  • Listeria monocytogenes / physiology*
  • Listeriosis / metabolism
  • Listeriosis / microbiology
  • Macrophages / microbiology*
  • Macrophages / physiology
  • Phagosomes / physiology
  • Type C Phospholipases / physiology

Substances

  • Actins
  • Bacterial Proteins
  • Bacterial Toxins
  • Heat-Shock Proteins
  • Hemolysin Proteins
  • Type C Phospholipases
  • hlyA protein, Listeria monocytogenes