TLR4-mediated expulsion of bacteria from infected bladder epithelial cells

Proc Natl Acad Sci U S A. 2009 Sep 1;106(35):14966-71. doi: 10.1073/pnas.0900527106. Epub 2009 Aug 17.

Abstract

Uropathogenic Escherichia coli invade bladder epithelial cells (BECs) by direct entry into specialized cAMP regulated exocytic compartments. Remarkably, a significant number of these intracellular bacteria are subsequently expelled in a nonlytic and piecemeal fashion by infected BECs. Here, we report that expulsion of intracellular E. coli by infected BECs is initiated by the pattern recognition receptor, Toll-like receptor (TLR)4, after activation by LPS. Also, we reveal that caveolin-1, Rab27b, PKA, and MyRIP are components of the exocytic compartment, and that they form a complex involved in the exocytosis of bacteria. This capacity of TLR4 to mediate the expulsion of intracellular bacteria from infected cells represents a previously unrecognized function for this innate immune receptor.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Caveolin 1 / metabolism
  • Cells, Cultured
  • Cyclic AMP / metabolism
  • Epithelial Cells / drug effects
  • Epithelial Cells / immunology*
  • Epithelial Cells / metabolism
  • Escherichia coli / immunology*
  • Exocytosis*
  • Humans
  • Lipopolysaccharides / immunology
  • Toll-Like Receptor 4 / immunology*
  • Toll-Like Receptor 4 / metabolism
  • Urinary Bladder / drug effects
  • Urinary Bladder / immunology*
  • Urinary Bladder / metabolism
  • Vesicular Transport Proteins / metabolism
  • rab GTP-Binding Proteins / metabolism

Substances

  • Caveolin 1
  • Lipopolysaccharides
  • MYRIP protein, human
  • TLR4 protein, human
  • Toll-Like Receptor 4
  • Vesicular Transport Proteins
  • Cyclic AMP
  • Rab27B protein, human
  • rab GTP-Binding Proteins