Selective increase of the permeability of polarized epithelial cell monolayers by Helicobacter pylori vacuolating toxin.
The effects of the vacuolating toxin (VacA) released by pathogenic strains of Helicobacter pylori on several polarized epithelial monolayers were investigated. Trans-epithelial electric resistance (TER) of monolayers formed by canine kidney MDCK I, human gut T84, and murine mammary gland epH4, was lowered by acid-activated VacA. Independent of the cell type and of the starting TER value, VacA reduced it to a minimal value of 1,000-1,300 Omega x cm2. TER decrease was paralleled by a three- to fourfold increase of [14C]-mannitol (molecular weight 182.2) and a twofold increase of [14C]-sucrose (molecular weight 342.3) transmonolayer flux. On the contrary, transmembrane flux of the proinflammatory model tripeptide [14C]-N-formyl-Met-Leu-Phe (molecular weight 437.6), of [3H]-inuline (molecular weight 5,000) and of HRP (molecular weight 47,000) did not change. These data indicate that VacA increases paracellular epithelial permeability to molecules with molecular weight < 350-440. Accordingly, the epithelial permeability of Fe3+ and Ni2+ ions, essential for H. pylori survival in vivo, was also increased by VacA. High-resolution immunofluorescence and SDS-PAGE analysis failed to reveal alterations of junctional proteins ZO-1, occludin, cingulin, and E-cadherin. It is proposed that induction by VacA of a selective permeabilization of the epithelial paracellular route to low molecular weight molecules and ions may serve to supply nutrients, which favor H. pylori growth in vivo.
Centro CNR Biomembrane and Dipartimento di Scienze, Biomediche, Università di Padova, 35121 Padova, Italy. papinie@civ.bio.unipd.it
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E
Papini
B
B
Satin
N
N
Norais
M
M
de Bernard
J L
JL
Telford
R
R
Rappuoli
C
C
Montecucco
D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D018938:Caco-2 Cells; D015820:Cadherins / Q000302:isolation & purification; D002412:Cations / Q000378:metabolism; D016764:Cell Polarity; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects*; D006367:HeLa Cells; D016480:Helicobacter pylori; D006735:Horseradish Peroxidase / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007365:Intercellular Junctions / Q000187:drug effects; D007444:Inulin / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D008353:Mannitol / Q000378:metabolism; D008565:Membrane Proteins / Q000302:isolation & purification; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism; D009532:Nickel / Q000378:metabolism; D010539:Permeability / Q000187:drug effects; D013276:Stomach Ulcer / Q000209:etiology; D013395:Sucrose / Q000378:metabolism
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D015820:Cadherins; D002412:Cations; D008565:Membrane Proteins; C074689:VacA protein, Helicobacter pylori; D008353:Mannitol; D013395:Sucrose; D009240:N-Formylmethionine Leucyl-Phenylalanine; D009532:Nickel; D007444:Inulin; D007501:Iron; D006735:Horseradish Peroxidase