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Strain-dependent induction of enterocyte apoptosis by Giardia lamblia disrupts epithelial barrier function in a caspase-3-dependent manner.
- Source :
-
Infection and immunity [Infect Immun] 2002 Jul; Vol. 70 (7), pp. 3673-80. - Publication Year :
- 2002
-
Abstract
- We recently demonstrated that Giardia lamblia rearranges cytoskeletal proteins and reduces transepithelial electrical resistance. The effect of G. lamblia on enterocyte apoptosis is unknown, and a possible link between microbially induced enterocyte apoptosis and altered epithelial permeability has yet to be established. The aim of this study was to assess whether G. lamblia induces enterocyte apoptosis in duodenal epithelial monolayers and whether this effect increases epithelial permeability. Monolayers of nontransformed human duodenal epithelial cells were incubated with sonicated or live G. lamblia trophozoites (NF, S2, WB, or PB strains) for 8, 24, and 48 h. Cell cultures were assessed for apoptosis by Hoechst fluorescence staining, enzyme-linked immunosorbent assay for apoptotic nucleosomes, and electron microscopy. In separate experiments, monolayers were pretreated with or without 120 microM caspase-3 inhibitor (Z-DEVD-FMK) for 1 h and were assessed for production of apoptotic nucleosomes, tight junctional integrity (with fluorescent ZO-1 staining followed by confocal laser microscopy), and transepithelial permeability for fluorescein isothiocyanate-dextran. G. lamblia strains NF and S2, but not strains WB or PB, induced enterocyte apoptosis within the monolayers, and this effect was inhibited by Z-DEVD-FMK pretreatment. Using the G. lamblia NF isolate, additional experiments investigated the possible link between enterocyte apoptosis and altered epithelial permeability. G. lamblia NF disrupted tight junctional ZO-1 and increased epithelial permeability, but these effects were also prevented by pretreatment with the caspase-3 inhibitor. These findings indicate that strain-dependent induction of enterocyte apoptosis may contribute to the pathogenesis of giardiasis. This effect is responsible for a loss of epithelial barrier function by disrupting tight junctional ZO-1 and increasing permeability in a caspase-3-dependent manner.
- Subjects :
- Animals
Caspase 3
Cell Membrane Permeability drug effects
Cells, Cultured
Cysteine Proteinase Inhibitors pharmacology
Duodenum cytology
Enterocytes drug effects
Enterocytes enzymology
Enterocytes parasitology
Epithelial Cells cytology
Epithelial Cells drug effects
Epithelial Cells parasitology
Humans
Intestinal Mucosa cytology
Membrane Proteins metabolism
Oligopeptides pharmacology
Phosphoproteins metabolism
Tight Junctions metabolism
Zonula Occludens-1 Protein
Apoptosis
Caspases metabolism
Cell Membrane Permeability physiology
Enterocytes cytology
Giardia lamblia physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0019-9567
- Volume :
- 70
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Infection and immunity
- Publication Type :
- Academic Journal
- Accession number :
- 12065509
- Full Text :
- https://doi.org/10.1128/IAI.70.7.3673-3680.2002