Escherichia coli K1-induced cytopathogenicity of human brain microvascular endothelial cells

Naveed Ahmed Khan, Junaid Iqbal, Ruqaiyyah Siddiqui

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Pathophysiology of Escherichia coli sepsis is complex involving circulating bacterial products, cytokine release, and sustained bacteremia resulting in the damage of vascular endothelium. Here, it is shown that E. coli K1 produced cytopathogenicity of human brain microvascular endothelial cells (HBMEC), that constitute the blood-brain barrier. Whole bacteria or their conditioned medium produced severe HBMEC damage suggesting E. coli K1-cytopathogenicity is a contact-independent process. Using lipopolysaccharide (LPS) inhibitor, polymyxin B, purified LPS extracted from E. coli K1 as well as LPS mutant derived from E. coli K1, we showed that LPS is not the sole determinant of E. coli K1-mediated HBMEC death. Bacterial product(s) for HBMEC cytopathogenicity was heat-labile suggesting LPS-associated proteins. Several isogenic gene-deletion mutants (Δ ompA, Δ ibeA, Δ ibeB, Δ cnf1) exhibited HBMEC cytopathogenicity similar to that produced by wild type E. coli K1. E. coli K1-mediated HBMEC death was independent of phosphatidylinositol 3-kinase (PI3K) but dependent partially on focal adhesion kinase (FAK) using HBMEC expressing dominant negative FAK and PI3K.

Original languageEnglish
Pages (from-to)269-275
Number of pages7
JournalMicrobial Pathogenesis
Issue number5-6
Publication statusPublished - Nov 2012


  • Cytopathogenicity
  • Endothelial cells
  • Lipopolysaccharide
  • Sepsis


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