Pasteurella multocida enters polarized epithelial cells by interacting with host F-actin

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M J Rabier1, N K Tyler, N J Walker

  • 1Department of Anatomy, School of Veterinary Medicine, University of California at Davis 95616, USA.

Veterinary Microbiology
|March 1, 1997
PubMed

Insights

Avian Pasteurella multocida invades host cells and reorganizes the actin cytoskeleton. Disrupting actin filaments with cytochalasin D inhibits bacterial entry, highlighting the cytoskeleton's role in infection.

Area of Science:

  • Microbiology
  • Cell Biology
  • Pathogen-Host Interactions

Background:

  • Polarized epithelial cells, such as Madin-Darby Canine Kidney (MDCK) cells grown on collagen, serve as models for studying host-pathogen interactions.
  • The cytoskeleton, particularly filamentous (F) actin, plays a crucial role in cellular processes including pathogen entry.
  • Pasteurella multocida is an avian pathogen that can cause significant disease.

Purpose of the Study:

  • To investigate the interaction between an avian strain of Pasteurella multocida and the cytoskeleton of MDCK cells.
  • To determine the temporal dynamics of bacterial entry and its association with the actin cytoskeleton.
  • To elucidate the role of the actin cytoskeleton in Pasteurella multocida infection.

Main Methods:

  • MDCK cells grown on collagen-coated filters were infected with Pasteurella multocida for varying durations (30 min to 6 hours).
  • Double-label immunofluorescence confocal microscopy was used to visualize bacteria and F-actin distribution.
  • Electron microscopy was employed to examine the ultrastructural association between bacteria and cytoskeletal filaments.
  • Cytochalasin D was used to disrupt the actin cytoskeleton and assess its effect on bacterial entry.

Main Results:

  • Pasteurella multocida entered MDCK cells within 30 minutes of incubation.
  • By 6 hours post-infection, the actin cytoskeleton showed significant reorganization, with long filaments replaced by discrete foci containing bacteria.
  • Electron microscopy revealed bacteria associated with short 5-6 nm filaments within 2 hours.
  • Pre-treatment with cytochalasin D disrupted the actin cytoskeleton and significantly inhibited Pasteurella multocida entry.

Conclusions:

  • Avian Pasteurella multocida interacts with and alters the actin cytoskeleton of MDCK cells during infection.
  • Bacterial entry is dependent on an intact actin cytoskeleton.
  • The findings provide insights into the mechanism of Pasteurella multocida pathogenesis at the cellular level.

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