Compartmentalizing intestinal epithelial cell toll-like receptors for immune surveillance

Cell Mol Life Sci. 2015 Sep;72(17):3343-53. doi: 10.1007/s00018-015-1931-1. Epub 2015 May 23.

Abstract

Toll-like receptors (TLRs) are membrane-bound microbial sensors that mediate important host-to-microbe responses. Cell biology aspects of TLR function have been intensively studied in professional immune cells, in particular the macrophages and dendritic cells, but not well explored in other specialized epithelial cell types. The adult intestinal epithelial cells are in close contact with trillions of enteric microbes and engage in lifelong immune surveillance. Mature intestinal epithelial cells, in contrast to immune cells, are highly polarized. Recent studies suggest that distinct mechanisms may govern TLR traffic and compartmentalization in these specialized epithelial cells to establish and maintain precise signaling of individual TLRs. We, using immune cells as references, discuss here the shared and/or unique molecular machineries used by intestinal epithelial cells to control TLR transport, localization, processing, activation, and signaling. A better understanding of these mechanisms will certainly generate important insights into both the mechanism and potential intervention of leading digestive disorders, in particular inflammatory bowel diseases.

Publication types

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

MeSH terms

  • Epithelial Cells / metabolism*
  • Humans
  • Immunologic Surveillance / physiology*
  • Inflammatory Bowel Diseases / genetics
  • Inflammatory Bowel Diseases / metabolism
  • Intestinal Mucosa / cytology*
  • Intestinal Mucosa / metabolism
  • Lipopolysaccharide Receptors / metabolism
  • Lymphocyte Antigen 96 / metabolism
  • Membrane Transport Proteins / metabolism
  • Models, Biological*
  • Protein Transport / physiology
  • Toll-Like Receptors / metabolism*
  • Vesicular Transport Proteins / metabolism

Substances

  • LY96 protein, human
  • Lipopolysaccharide Receptors
  • Lymphocyte Antigen 96
  • Membrane Transport Proteins
  • TMED7 protein, human
  • Toll-Like Receptors
  • UNC93B1 protein, human
  • Vesicular Transport Proteins