Clostridium difficile toxin A induces intestinal epithelial cell apoptosis and damage: role of Gln and Ala-Gln in toxin A effects

Dig Dis Sci. 2005 Jul;50(7):1271-8. doi: 10.1007/s10620-005-2771-x.


The aim of this study was to investigate the effect of Clostridium difficile toxin A (TxA) on intestinal epithelial cell migration, apoptosis, and transepithelial resistance and to evaluate the effect of glutamine (Gln) and its stable derivative, alanyl-glutamine (Ala-Gln), on TxA-induced damage. Migration was measured in rat intestinal epithelial cells (IEC-6) 6 and 24 hr after a razor scrape of the cell monolayer. Cell proliferation was indirectly measured utilizing the tetrazolium salt WST-1. The cells were incubated with TxA (1-100 ng/ml) in medium without Gln or medium containing Gln or Ala-Gln (1-30 mM). Apoptosis was quantified in IEC-6 cells using annexin V assay. Transepithelial resistance was measured using an epithelial voltohmmeter across T84 cells seeded on a transwell filter. TxA-induced a dose-dependent reduction of migration and also caused dose and time-dependent apoptosis in IEC-6 cells. Gln and Aln-Gln significantly enhanced IEC-6 cell migration and proliferation. Gln and Ala-Gln also prevented the inhibition of migration, apoptosis, and the initial drop in transepithelial resistance induced by TxA. In conclusion, both peptides reduced toxin-induced epithelial damage and thus might play an adjunctive role in C. difficile-induced colitis therapy.

Publication types

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

MeSH terms

  • Animals
  • Apoptosis*
  • Bacterial Toxins / administration & dosage
  • Bacterial Toxins / pharmacology*
  • Cell Line
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Dipeptides / metabolism*
  • Dipeptides / pharmacology
  • Dose-Response Relationship, Drug
  • Electric Impedance
  • Enterotoxins / administration & dosage
  • Enterotoxins / pharmacology*
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Epithelial Cells / pathology
  • Glutamine / metabolism*
  • Glutamine / pharmacology
  • Intestines / drug effects
  • Intestines / pathology*
  • Intestines / physiopathology*
  • Necrosis
  • Rats
  • Time Factors


  • Bacterial Toxins
  • Dipeptides
  • Enterotoxins
  • tcdA protein, Clostridium difficile
  • Glutamine
  • alanylglutamine