Rapid, transient phosphatidylserine externalization induced in host cells by infection with Chlamydia spp

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S R Goth1, R S Stephens

  • 1Division of Infectious Diseases, School of Public Health, University of California, Berkeley, California 94720, USA.

Infection and Immunity
|February 13, 2001
PubMed

Insights

Chlamydia bacterial infections cause cells to expose phosphatidylserine, a lipid molecule. This externalization accelerates blood clotting and enhances macrophage engulfment of infected cells, impacting chlamydial disease.

Area of Science:

  • Microbiology
  • Cell Biology
  • Immunology

Background:

  • Chlamydia are obligate intracellular bacteria causing human diseases like ocular scarring and atherosclerosis.
  • Understanding Chlamydia pathogenesis is crucial for developing effective treatments.

Purpose of the Study:

  • To investigate the effect of Chlamydia trachomatis and Chlamydia pneumoniae infection on host cell membranes.
  • To determine the role of phosphatidylserine externalization in Chlamydia pathogenesis.

Main Methods:

  • In vitro infection of human epithelial, endothelial, granulocytic, and monocytic cells with Chlamydia.
  • Analysis of phosphatidylserine externalization using flow cytometry and microscopy.
  • Assays to measure plasma clotting time and macrophage phagocytosis.

Main Results:

  • Chlamydia infection rapidly induced phosphatidylserine externalization in various human cell types.
  • This process was calcium-dependent, transient, and infectious dose-dependent.
  • Infected cells accelerated plasma clotting and enhanced macrophage phagocytosis in a phosphatidylserine-dependent manner.
  • Caspase inhibition did not affect infection-induced phosphatidylserine externalization.

Conclusions:

  • Chlamydia infection triggers phosphatidylserine externalization on host cells.
  • This lipid exposure plays a significant role in Chlamydia pathogenesis by influencing coagulation and immune cell interactions.
  • Targeting phosphatidylserine externalization may offer novel therapeutic strategies against chlamydial infections.

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