Alanyl-glutamine Protects Against Damage Induced by Enteroaggregative Escherichia coli Strains in Intestinal Cells

J Pediatr Gastroenterol Nutr. 2019 Feb;68(2):190-198. doi: 10.1097/MPG.0000000000002152.

Abstract

Background: Enteroaggregative Escherichia coli (EAEC) is an important pathogen causing enteric infections worldwide. This pathotype is linked to malnutrition in children from developing countries. Alanyl-glutamine (Ala-Gln) is an immune modulator nutrient that acts during intestinal damage and/or inflammation. This study investigated the effect of EAEC infection and Ala-Gln on cell viability, cell death, and inflammation of intestinal epithelium cells (IEC-6).

Methods: Cells were infected with an EAEC prototype 042 strain, an EAEC wild-type strain isolated from a Brazilian malnourished child, and a commensal E coli HS. Gene transcription and protein levels of caspases-3, -8, and -9 and cytokine-induced neutrophil chemoattractant 1 (CINC-1/CXCL1) were evaluated using RT-qPCR, western blot analysis, and ELISA.

Results: Infections with both EAEC strains decreased cell viability and induced apoptosis and necrosis after 24 hours. Ala-Gln supplementation increased cell proliferation and reduced cell death in infected cells. Likewise, EAEC strain 042 significantly increased the transcript levels of caspases-3, -8, and -9 when compared to the control group, and Ala-Gln treatment reversed this effect. Furthermore, EAEC induced CXCL1 protein levels, which were also reduced by Ala-Gln supplementation.

Conclusion: These findings suggest that EAEC infection promotes apoptosis, necrosis, and intestinal inflammation with involvement of caspases. Supplementation of Ala-Gln inhibits cell death, increases cell proliferation, attenuates mediators associated with cell death, and inflammatory pathways in infected cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Survival / drug effects*
  • Chemokine CXCL1 / metabolism
  • Child
  • Dietary Supplements
  • Dipeptides / pharmacology*
  • Epithelial Cells / metabolism
  • Epithelial Cells / microbiology
  • Escherichia coli / metabolism*
  • Escherichia coli Infections / metabolism
  • Escherichia coli Infections / microbiology
  • Escherichia coli Infections / therapy*
  • Humans
  • Intestinal Mucosa / cytology
  • Intestinal Mucosa / microbiology
  • Protective Agents / pharmacology*

Substances

  • CXCL1 protein, human
  • Chemokine CXCL1
  • Dipeptides
  • Protective Agents
  • alanylglutamine