Caco-2/HT29-MTX co-cultured cells as a model for studying physiological properties and toxin-induced effects on intestinal cells

PLoS One. 2021 Oct 7;16(10):e0257824. doi: 10.1371/journal.pone.0257824. eCollection 2021.

Abstract

Infectious gastrointestinal diseases are frequently caused by toxins secreted by pathogens which may impair physiological functions of the intestines, for instance by cholera toxin or by heat-labile enterotoxin. To obtain a functional model of the human intestinal epithelium for studying toxin-induced disease mechanisms, differentiated enterocyte-like Caco-2 cells were co-cultured with goblet cell-like HT29-MTX cells. These co-cultures formed a functional epithelial barrier, as characterized by a high electrical resistance and the presence of physiological intestinal properties such as glucose transport and chloride secretion which could be demonstrated electrophysiologically and by measuring protein expression. When the tissues were exposed to cholera toxin or heat-labile enterotoxin in the Ussing chamber, cholera toxin incubation resulted in an increase in short-circuit currents, indicating an increase in apical chloride secretion. This is in line with typical cholera toxin-induced secretory diarrhea in humans, while heat-labile enterotoxin only showed an increase in short-circuit-current in Caco-2 cells. This study characterizes for the first time the simultaneous measurement of physiological properties on a functional and structural level combined with the epithelial responses to bacterial toxins. In conclusion, using this model, physiological responses of the intestine to bacterial toxins can be investigated and characterized. Therefore, this model can serve as an alternative to the use of laboratory animals for characterizing pathophysiological mechanisms of enterotoxins at the intestinal level.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Toxins / chemistry
  • Bacterial Toxins / metabolism*
  • Caco-2 Cells
  • Chlorides / metabolism
  • Cholera Toxin / chemistry
  • Cholera Toxin / metabolism*
  • Coculture Techniques
  • Communicable Diseases / microbiology*
  • Communicable Diseases / pathology
  • Enterotoxins / chemistry
  • Enterotoxins / metabolism
  • Escherichia coli / genetics
  • Escherichia coli Proteins / genetics
  • Gastrointestinal Diseases / microbiology*
  • Gastrointestinal Diseases / pathology
  • Glucose / metabolism
  • HT29 Cells
  • Humans
  • Intestinal Mucosa / drug effects

Substances

  • Bacterial Toxins
  • Chlorides
  • Enterotoxins
  • Escherichia coli Proteins
  • Cholera Toxin
  • Glucose

Grants and funding

This project was funded by the Federal State of Lower Saxony in the joint project R2N – “Replace” and “Reduce” in Niedersachsen (Lower Saxony) – Alternative methods to replace or reduce animal models in biomedical research. No specific person was funded but the project itself. Additionally, this publication was supported by open access funds from Deutsche Forschungsgemeinschaft and University of Veterinary Medicine Hannover, Foundation. The funding is not specific to one of the authors but to the publication itself. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.