[HTML][HTML] Epithelial cell apoptosis facilitates Entamoeba histolytica infection in the gut

SM Becker, KN Cho, X Guo, K Fendig… - The American journal of …, 2010 - Elsevier
SM Becker, KN Cho, X Guo, K Fendig, MN Oosman, R Whitehead, SM Cohn, ER Houpt
The American journal of pathology, 2010Elsevier
Entamoeba histolytica is the protozoan parasite that causes amebic colitis. The parasite
triggers apoptosis on contact with host cells; however, the biological significance of this
event during intestinal infection is unclear. We examined the role of apoptosis in a mouse
model of intestinal amebiasis. Histopathology revealed that abundant epithelial cell
apoptosis occurred in the vicinity of amoeba in histological specimens. Epithelial cell
apoptosis occurred rapidly on co-culture with amoeba in vitro as measured by annexin …
Entamoeba histolytica is the protozoan parasite that causes amebic colitis. The parasite triggers apoptosis on contact with host cells; however, the biological significance of this event during intestinal infection is unclear. We examined the role of apoptosis in a mouse model of intestinal amebiasis. Histopathology revealed that abundant epithelial cell apoptosis occurred in the vicinity of amoeba in histological specimens. Epithelial cell apoptosis occurred rapidly on co-culture with amoeba in vitro as measured by annexin positivity, DNA degradation, and mitochondrial dysfunction. Administration of the pan caspase inhibitor ZVAD decreased the rate and severity of amebic infection in CBA mice by all measures (cecal culture positivity, parasite enzyme-linked immunosorbent assay, and histological scores). Similarly, caspase 3 knockout mice on the resistant C57BL/6 background exhibited even lower cecal parasite antigen burden and culture positive rates than wild type mice. The permissive effect of apoptosis on infection could be tracked to the epithelium, in that transgenic mice that overexpressed Bcl-2 in epithelial cells were more resistant to infection as measured by cecal parasite enzyme-linked immunosorbent assay and histological scores. We concluded that epithelial cell apoptosis in the intestine facilitates amebic infection in this mouse model. The parasite's strategy for inducing apoptosis may point to key virulence factors, and therapeutic maneuvers to diminish epithelial apoptosis may be useful in amebic colitis.
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