Caspase-dependent apoptosis of the HCT-8 epithelial cell line induced by the parasite Giardia intestinalis.
Giardia intestinalis is a flagellated protozoan which causes enteric disease worldwide. Giardia trophozoites infect epithelial cells of the proximal small intestine and can cause acute or chronic diarrhea. The mechanism of epithelial injury in giardiasis remains unknown. A number of enteric pathogens, including protozoan parasites, are able to induce enterocyte apoptosis. The aim of this work was to assess whether G. intestinalis strain WB clone C6 is able to induce apoptosis in the human intestinal epithelial cell line HCT-8, and to investigate the role of caspases in this process. Results demonstrated that the parasite induces cell apoptosis, as confirmed by DNA fragmentation analysis, detection of active caspase-3 and degradation of the caspase-3 substrate PARP [poly(ADP-ribose) polymerase]. Furthermore, G. intestinalis infection induces activation of both the intrinsic and the extrinsic apoptotic pathways, down-regulation of the antiapoptotic protein Bcl-2 and up-regulation of the proapoptotic Bax, suggesting a possible role for caspase-dependent apoptosis in the pathogenesis of giardiasis.
Panaro
Maria Antonietta
MA
Department of Human Anatomy and Histology, University of Bari, Bari, Italy. ma.panaro@anatomia.uniba.it
Cianciulli
Antonia
A
Mitolo
Vincenzo
V
Mitolo
Carlo Ivan
CI
Acquafredda
Angela
A
Brandonisio
Olga
O
Cavallo
Pasqua
P
D000818:Animals; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism*; D045744:Cell Line, Tumor; D053938:DNA Fragmentation; D004847:Epithelial Cells / Q000469:parasitology*; D005786:Gene Expression Regulation; D016829:Giardia lamblia / Q000502:physiology*; D006801:Humans; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis
D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D011065:Poly(ADP-ribose) Polymerases; D053148:Caspase 3