title: Overexpression of specific cysteine peptidases confers pathogenicity to a nonpathogenic Entamoeba histolytica clone.
abstract: Cysteine peptidases (CPs) of Entamoeba histolytica are considered to be important pathogenicity factors. Previous studies have found that under standard axenic culture conditions, only four (ehcp-a1, ehcp-a2, ehcp-a5, and ehcp-a7) out of 35 papain-like ehcp genes present in the E. histolytica genome are expressed at high levels. Little is known about the expression of CPs in E. histolytica during amoebic liver abscess (ALA) formation. In the current study, a quantitative real-time PCR assay was developed to determine the expression of the various ehcp genes during ALA formation in animal models. Increased expression of four ehcp genes (ehcp-a3, -a4, -a10, and -c13) was detected in the gerbil and mouse models. Increased expression of another three ehcp genes (ehcp-a5, -a6, and -a7) was detected in the mouse model only, and two other ehcp genes (ehcp-b8 and -b9) showed increased expression in the gerbil model only. Trophozoites of the nonpathogenic E. histolytica HM-1:IMSS clone A1, which was unable to induce ALAs, were transfected with vectors enabling overexpression of those CPs that are expressed at high levels under culture conditions or during ALA formation. Interestingly, overexpression of ehcp-b8, -b9, and -c13 restored the pathogenic phenotype of the nonpathogenic clone A1 whereas overexpression of various other peptidase genes had no effect on the pathogenicity of this clone.
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
authors.forename: Jenny
authors.initials: J
authors.lastname: Matthiesen
authors.forename: Ann-Katrein
authors.initials: AK
authors.lastname: Bär
authors.forename: Anne-Kathrin
authors.initials: AK
authors.lastname: Bartels
authors.forename: Dennis
authors.initials: D
authors.lastname: Marien
authors.forename: Susann
authors.initials: S
authors.lastname: Ofori
authors.forename: Laura
authors.initials: L
authors.lastname: Biller
authors.forename: Egbert
authors.initials: E
authors.lastname: Tannich
authors.forename: Hannelore
authors.initials: H
authors.lastname: Lotter
authors.forename: Iris
authors.initials: I
authors.lastname: Bruchhaus
mesh_terms: D000818:Animals; D057056:Cysteine Proteases / Q000096:biosynthesis*; D004195:Disease Models, Animal; D004748:Entamoeba histolytica / Q000201:enzymology* / Q000472:pathogenicity*; D015870:Gene Expression; D020869:Gene Expression Profiling; D005849:Gerbillinae; D008101:Liver Abscess, Amebic / Q000469:parasitology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D060888:Real-Time Polymerase Chain Reaction; D015854:Up-Regulation; D037521:Virulence Factors / Q000096:biosynthesis*
chemical_list: D037521:Virulence Factors; D057056:Cysteine Proteases