Helicobacter pylori vacuolating toxin accumulates within the endosomal- vacuolar compartment of cultured gastric cells and potentiates the vacuolating activity of ammonia

V. Ricci, P. Sommi, R. Fiocca, M. Romano, E. Solcia, U. Ventura

Research output: Contribution to journalArticlepeer-review

Abstract

This study explored the relationship between vacuolating toxin and ammonia in the genesis of Helicobacter pylori-induced vacuolation in cultured human gastric cells and investigated the intracellular sites of toxin accumulation. Neutral red dye uptake and electron microscopy were used in the investigation of the respective roles of, and of the reciprocal interaction between, toxin and ammonia in cell vacuolation and ultrastructural immunocytochemistry was used for the identification of the intracellular sites of internalized toxin. Toxin was found to cause an expansion of the endosomal compartment, where it accumulates after cellular internalization. However, toxin does not form large, neutral red-positive vacuoles unless combined with ammonia, whose moderate vacuolating activity is markedly potentiated by the toxin. It is concluded that the toxin accumulated within the endosomal compartment alters the morphology and function of this organelle and plays a permissive role towards cell vacuolation, possibly by increasing the accumulation of protonated ammonia within endosomes. In turn, ammonia induces excessive dilatation of the endosomes with reciprocal fusion of their membranes, thus causing cytoplasmic vacuolation.

Original languageEnglish
Pages (from-to)453-459
Number of pages7
JournalJournal of Pathology
Volume183
Issue number4
DOIs
Publication statusPublished - Dec 1997

Keywords

  • Ammonia
  • Cell vacuolation
  • Endosomes
  • Helicobacter pylori
  • Toxin internalization
  • Ultrastructural immunocytochemistry
  • Vacuolating toxin

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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