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Chlamydia pneumoniae infection promotes the transmigration of monocytes through human brain endothelial cells

A MacIntyre1, R Abramov, C J Hammond

  • 1Department of Biomedical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, USA.

Journal of Neuroscience Research
|February 14, 2003
PubMed

Insights

Chlamydia pneumoniae infection promotes the entry of monocytes into the brain by affecting human brain endothelial cells (HBMECs). This vascular infection may initiate neuroinflammation in Alzheimer's disease (AD).

Area of Science:

  • Neuroscience
  • Infectious Disease
  • Cell Biology

Background:

  • Alzheimer's disease (AD) pathogenesis involves neuroinflammation and potential breaches in the blood-brain barrier (BBB).
  • Chlamydia pneumoniae (C. pneumoniae) is a pathogen implicated in various inflammatory conditions, with potential links to neurological disorders.

Purpose of the Study:

  • To investigate the role of C. pneumoniae in breaching the BBB by examining its effects on human brain endothelial cells (HBMECs) and human monocytes.
  • To understand the cellular mechanisms by which C. pneumoniae may facilitate entry into the central nervous system (CNS).

Main Methods:

  • In vitro studies using HBMECs and THP-1 monocytes exposed to C. pneumoniae.
  • Analysis of cell surface marker expression (VCAM-1, ICAM-1, LFA-1, VLA-4, MAC-1).
  • Assessment of monocyte transmigration across an endothelial cell monolayer.

Main Results:

  • C. pneumoniae was found to infect HBMECs and monocytes in AD brain tissues more than in normal brain tissues.
  • Infection by C. pneumoniae stimulated monocyte transendothelial migration through HBMECs.
  • Upregulation of specific adhesion molecules (VCAM-1, ICAM-1, LFA-1, VLA-4, MAC-1) was observed, facilitating monocyte transmigration.
  • C. pneumoniae infection increased monocyte transmigration threefold in an in vitro model.

Conclusions:

  • C. pneumoniae infection of vasculature and monocytes may facilitate their entry into the brain, contributing to neuroinflammation in AD.
  • Vascular infection by C. pneumoniae could be a key initiating factor in the pathogenesis of neurodegenerative diseases like sporadic AD.

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