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Anaplasma phagocytophilum infection induces apoptosis in HL-60 cells

Pratap Karki1, Jacob W Ijdo

  • 1Inflammation Program and Division of Rheumatology, Department of Internal Medicine, University of Iowa and Veterans Administration Medical Center, 2501 Crosspark Road, MTF E104, Coralville, Iowa City, IA 52241, USA.

World Journal of Microbiology & Biotechnology
|October 18, 2011
PubMed

Insights

Anaplasma phagocytophilum infection promotes apoptosis in human leukemia cells (HL-60), unlike its anti-apoptotic effect in neutrophils. This finding impacts understanding of anaplasmosis pathogenesis.

Area of Science:

  • Microbiology
  • Cell Biology
  • Pathogenesis

Background:

  • Anaplasma phagocytophilum causes human granulocytic anaplasmosis.
  • This obligate intracellular bacterium delays neutrophil apoptosis for survival.
  • The HL-60 cell line is commonly used for in vitro Anaplasma culture.

Purpose of the Study:

  • To investigate the effects of Anaplasma phagocytophilum infection on drug-induced apoptosis in HL-60 cells.
  • To compare the apoptotic response in infected HL-60 cells versus neutrophils.

Main Methods:

  • Culturing Anaplasma phagocytophilum in HL-60 cells.
  • Inducing apoptosis using staurosporine and etoposide.
  • Assessing cell viability and apoptosis markers.

Main Results:

  • Anaplasma infection reduced HL-60 cell viability.
  • Infection increased spontaneous and drug-induced apoptosis in HL-60 cells.
  • Apoptosis was significantly exacerbated by Anaplasma in staurosporine/etoposide-treated cells.

Conclusions:

  • Anaplasma phagocytophilum infection exhibits a pro-apoptotic effect in HL-60 cells.
  • This contrasts with the known anti-apoptotic role of the bacterium in neutrophils.
  • Findings suggest differential apoptotic regulation by Anaplasma in distinct host cell types.

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