Entamoeba histolytica contains an occludin-like protein that can alter colonic epithelial barrier function.
The exact mechanism by which Entamoeba histolytica disrupts the human colonic epithelium and invades the mucosa has yet to be clearly elucidated. E. histolytica produces a diverse array of putative virulent factors such as glycosidase, cysteine proteinases and amebapore that can modulate and/or disrupt epithelial barrier functions. However, it is currently thought that E. histolytica produces numerous other molecules and strategies to disrupt colonic mucosal defenses. In this study, we document a putative mechanism whereby the parasite alters the integrity of human epithelium by expressing a cognate tight junction protein of the host. We detected this protein as "occludin-like" as revealed by immunoblotting and immunoprecipitation studies and visualization by confocal microscopy using antibodies highly specific for human occludin. We propose that E. histolytica occludin-like protein might displace mucosal epithelial occludin-occludin tight junction interactions resulting in epithelial disruption analogous to sub mucosal human dendritic cells sampling luminal contents. These results indicate that E. histolytica occludin is a putative virulent component that can play a role in the pathogenesis of intestinal amebiasis.
Gastrointestinal Research Group, Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
Michael
M
Goplen
Manigandan
M
Lejeune
Steve
S
Cornick
France
F
Moreau
Kris
K
Chadee
D015153:Blotting, Western; D002460:Cell Line; D003106:Colon / Q000378:metabolism / Q000469:parasitology / Q000473:pathology; D004748:Entamoeba histolytica / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D004847:Epithelial Cells / Q000378:metabolism / Q000469:parasitology* / Q000473:pathology; D005786:Gene Expression Regulation; D006790:Host-Parasite Interactions; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000469:parasitology / Q000473:pathology; D018613:Microscopy, Confocal; D062793:Occludin / Q000235:genetics* / Q000378:metabolism; D010539:Permeability; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D013045:Species Specificity; D019108:Tight Junctions / Q000378:metabolism / Q000469:parasitology* / Q000473:pathology; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
D062793:Occludin; D015800:Protozoan Proteins; D037521:Virulence Factors