Escherichia coli DraE adhesin-associated bacterial internalization by epithelial cells is promoted independently by decay-accelerating factor and carcinoembryonic antigen-related cell adhesion molecule binding and does not require the DraD invasin

Infect Immun. 2008 Sep;76(9):3869-80. doi: 10.1128/IAI.00427-08. Epub 2008 Jun 16.

Abstract

The Dr family of Escherichia coli adhesins are virulence factors associated with diarrhea and urinary tract infections. Dr fimbriae are comprised of two subunits. DraE/AfaE represents the major structural, antigenic, and adhesive subunit, which recognizes decay-accelerating factor (DAF) and carcinoembryonic antigen (CEA)-related cell adhesion molecules (CEACAMs) CEA, CEACAM1, CEACAM3, and CEACAM6 as binding receptors. The DraD/AfaD subunit caps fimbriae and has been implicated in the entry of Dr-fimbriated E. coli into host cells. In this study, we demonstrate that DAF or CEACAM receptors independently promote DraE-mediated internalization of E. coli by CHO cell transfectants expressing these receptors. We also found that DraE-positive recombinant bacteria adhere to and are internalized by primary human bladder epithelial cells which express DAF and CEACAMs. DraE-mediated bacterial internalization by bladder cells was inhibited by agents which disrupt lipid rafts, microtubules, and phosphatidylinositol 3-kinase (PI3K) activity. Immunofluorescence confocal microscopic examination of epithelial cells detected considerable recruitment of caveolin, beta(1) integrin, phosphorylated ezrin, phosphorylated PI3K, and tubulin, but not F-actin, by cell-associated bacteria. Finally, we demonstrate that the DraD subunit, previously implicated as an "invasin," is not required for beta(1) integrin recruitment or bacterial internalization.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / physiology*
  • Animals
  • Bacterial Adhesion*
  • CD55 Antigens / metabolism*
  • CHO Cells
  • Caco-2 Cells
  • Cell Adhesion Molecules / metabolism*
  • Cricetinae
  • Cricetulus
  • Epithelial Cells / microbiology*
  • Escherichia coli / physiology*
  • Escherichia coli Proteins / physiology*
  • Fimbriae Proteins / physiology*
  • Humans
  • Protein Binding

Substances

  • Adhesins, Bacterial
  • CD55 Antigens
  • Cell Adhesion Molecules
  • DraD invasin, E coli
  • DraE protein, E coli
  • Escherichia coli Proteins
  • Fimbriae Proteins