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Infection by microsporidia disrupts the host cell cycle

M Scanlon1, A P Shaw, C J Zhou

  • 1Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia 30310, USA. scanlon@msm.edu

The Journal of Eukaryotic Microbiology
|December 29, 2000
PubMed

Insights

Encephalitozoon microsporidia infection halts host cell division, preventing parasite spread. Studies show infected cells are blocked at multiple cell cycle stages, ensuring parasite survival and development.

Area of Science:

  • Cell Biology
  • Parasitology
  • Immunology

Background:

  • Microsporidia of the genus Encephalitozoon are opportunistic pathogens causing disease in immunocompromised individuals.
  • These parasites develop within host cells, residing in enlarged parasitophorous vacuoles that occupy significant cellular volume.
  • Parasite-induced manipulation of host cell processes is crucial for its growth and survival.

Purpose of the Study:

  • To investigate the hypothesis that Encephalitozoon microsporidia infection induces host cell cycle arrest.
  • To understand how parasites ensure optimal conditions for development by preventing host cell division.

Main Methods:

  • Comparative analysis of infected versus uninfected mammalian cells.
  • Assessment of mitotic index and DNA duplication rates.
  • Flow cytometry to analyze cell cycle distribution (G1, S, G2/M phases).
  • Western blot analysis to determine levels of key cell cycle regulatory proteins (cyclin D1, cyclin B1).

Main Results:

  • Reduced mitotic index and DNA duplication in infected cells.
  • Increased proportion of host cells in the S phase.
  • Decreased levels of cyclin D1 and reduced percentage of cells in G1 phase.
  • Elevated levels of cyclin B1 despite a decreased percentage of cells in G2/M phase.
  • Evidence of cell cycle arrest at multiple checkpoints.

Conclusions:

  • Encephalitozoon microsporidia infection triggers host cell cycle arrest.
  • This arrest occurs at multiple points within the cell cycle, including G1 and G2/M phases.
  • Cell cycle arrest is a key mechanism by which these parasites ensure their own replication and survival within the host.

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