Interferon-gamma increases hPepT1-mediated uptake of di-tripeptides including the bacterial tripeptide fMLP in polarized intestinal epithelia

Am J Pathol. 2003 Nov;163(5):1969-77. doi: 10.1016/s0002-9440(10)63555-9.

Abstract

Interferon-gamma causes a global phenotypic switch in intestinal epithelial function, in which enterocytes become immune accessory cells. The phenotypic switch is characterized by a down-regulation of membrane transporters and up-regulation of immune accessory molecules in intestinal epithelial cells. However, the effect of interferon-gamma on the intestinal epithelia di-tripeptide hPepT1 transporter has not been investigated. In this study we demonstrate that 1) interferon-gamma increases di-tripeptide uptake in dose- and time-dependent manner in model intestinal epithelia (Caco-2 BBE cell monolayers), 2) the increase in di-tripeptides induced by interferon-gamma is hPepT1 mediated, 3) interferon-gamma does not affect the hPept1 expression at the mRNA and protein levels 4) interferon-gamma increases the intracellular pH and consequently enhances the H+-electrochemical gradient across apical plasma membrane in model intestinal epithelia (Caco2-BBE monolayers). We suggest that interferon-gamma could increase the hPepT1 mediated di-tripeptides uptake in inflamed epithelial cells. Under these conditions, interferon-gamma will increase the intracellular amount of such diverse prokaryotic and eucaryotic small di-tripeptides in inflamed epithelial cells. The intracellular accumulation of such di-tripeptides may be important in enterocytes becoming immune accessory cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antiviral Agents / metabolism
  • Antiviral Agents / pharmacology*
  • Bacterial Proteins / metabolism*
  • Biological Transport / drug effects
  • Blotting, Northern
  • Blotting, Western
  • Caco-2 Cells
  • Carrier Proteins / drug effects
  • Carrier Proteins / metabolism*
  • Cell Polarity / drug effects
  • Cytoplasm / chemistry
  • Cytoplasm / drug effects
  • Dipeptides / metabolism
  • Dose-Response Relationship, Drug
  • Humans
  • Hydrogen-Ion Concentration / drug effects
  • Interferon-gamma / metabolism
  • Interferon-gamma / pharmacology*
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / metabolism
  • Microscopy, Confocal
  • Peptide Transporter 1
  • Symporters*
  • Time Factors

Substances

  • Antiviral Agents
  • Bacterial Proteins
  • Carrier Proteins
  • Dipeptides
  • Peptide Transporter 1
  • SLC15A1 protein, human
  • Symporters
  • Interferon-gamma