Cholera toxin disrupts barrier function by inhibiting exocyst-mediated trafficking of host proteins to intestinal cell junctions

Cell Host Microbe. 2013 Sep 11;14(3):294-305. doi: 10.1016/j.chom.2013.08.001.

Abstract

Cholera toxin (CT), a virulence factor elaborated by Vibrio cholerae, is sufficient to induce the severe diarrhea characteristic of cholera. The enzymatic moiety of CT (CtxA) increases cAMP synthesis in intestinal epithelial cells, leading to chloride ion (Cl(-)) efflux through the CFTR Cl(-) channel. To preserve electroneutrality and osmotic balance, sodium ions and water also flow into the intestinal lumen via a paracellular route. We find that CtxA-driven cAMP increase also inhibits Rab11/exocyst-mediated trafficking of host proteins including E-cadherin and Notch signaling components to cell-cell junctions in Drosophila, human intestinal epithelial cells, and ligated mouse ileal loops, thereby disrupting barrier function. Additionally, CtxA induces junctional damage, weight loss, and dye leakage in the Drosophila gut, contributing to lethality from live V. cholerae infection, all of which can be rescued by Rab11 overexpression. These barrier-disrupting effects of CtxA may act in parallel with Cl(-) secretion to drive the pathophysiology of cholera.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Line
  • Chlorine / metabolism
  • Cholera Toxin / metabolism*
  • Cyclic AMP / metabolism
  • Disease Models, Animal
  • Drosophila
  • Epithelial Cells / drug effects
  • Epithelial Cells / physiology*
  • Exosomes / drug effects*
  • GTP-Binding Proteins / metabolism
  • Host-Pathogen Interactions*
  • Humans
  • Mice
  • Models, Biological
  • Sodium / metabolism
  • Survival Analysis
  • Tight Junction Proteins / antagonists & inhibitors*
  • Tight Junctions / drug effects
  • Tight Junctions / physiology*
  • Vibrio cholerae / physiology*
  • Water / metabolism

Substances

  • Tight Junction Proteins
  • Water
  • Chlorine
  • Cholera Toxin
  • Sodium
  • Cyclic AMP
  • GTP-Binding Proteins