Comparison of two genetically related Entamoeba histolytica cell lines derived from the same isolate with different pathogenic properties

Abstract

Entamoeba histolytica is known for its extraordinary capacity to destroy human tissues, leading to invasive diseases such as ulcerative colitis or extra-intestinal abscesses. In order to identify the virulence factors of this parasite phenotypes and proteomes of two recently identified genetically related cell lines (A and B), derived from the laboratory E. histolytica isolate HM-1:IMSS, were compared. Both cell lines are indistinguishable on the basis of highly polymorphic tandem repeat DNA sequences. However, cell line A is incapable to induce liver abscesses in experimentally infected rodents, whereas cell line B provokes considerable abscesses. Phenotypic analyses revealed increased hemolytic activity, lower growth rate, smaller cell size, reduced cysteine peptidase activity and lower resistance to nitric oxide stress for cell line A. In contrast, no differences between the two cell lines were found for cytopathic activity, erythrophagocytosis, digestion of erythrocytes or resistance to complement, hydrogen peroxide and superoxide radical anions. Proteomic comparison by 2-D DIGE followed by MS, identified a total of 21 proteins with higher abundance in cell line A and ten proteins with higher abundance in cell line B. Remarkably, three differentially up-regulated antioxidants were exclusively found in the pathogenic cell line B. Notably, only for two differentially regulated proteins, namely a Fe-hydrogenase and a C2 domain protein, a similar type was found at the level of transcription. Summarized, a defined set of different proteins could be identified between cell lines A and B. These molecules may have an important role in amoeba pathogenicity.

Overexpression of Differentially Expressed Genes Identified in Non-pathogenic and Pathogenic Entamoeba histolytica Clones Allow Identification of New Pathogenicity Factors Involved in Amoebic Liver Abscess Formation

“…Recently, it was shown that CP activity of the pathogenic cell line HM-1:IMSS-B is approximately ten times greater (110 ± 25 mU/mg) than in the non-pathogenic cell line HM-1:IMSS-A (15 ± 5 mU/mg) [11]. A similar difference has been measured for the non-pathogenic clone A1 np (15 ± 10 mU/mg) and the pathogenic clone B2 p (123 ± 60 mU/mg) [3].…”

“…Whereas cell line HM-1:IMSS-A completely lost its ability to induce ALAs in gerbils ( Meriones unguiculatus ) and mice ( Mus musculus ), cell line HM-1:IMSS-B is highly aggressive and induces large ALAs. Comparative transcriptomic and proteomic studies of these cell lines have already been performed [11]. The studies revealed 31 differentially (≥3-fold) expressed genes [12] and 31 proteins with differential abundances in HM-1:IMSS-A and HM-1:IMSS-B [11].…”

“…Comparative transcriptomic and proteomic studies of these cell lines have already been performed [11]. The studies revealed 31 differentially (≥3-fold) expressed genes [12] and 31 proteins with differential abundances in HM-1:IMSS-A and HM-1:IMSS-B [11]. However, an overlap of only two molecules was found between the proteomic and transcriptomic approaches.…”

The tRNA Gene-Linked STRs and Other Genetic Typing Methods

“…Two cell lines with identical patterns at six STRs derived from the most widely used E. histolytica HM-1:IMSS isolate showed two different virulence phenotypes: one was highly virulent in experimental animals while the other was not [ 42 ]. In a recent study in China, Feng et al [ 43 ] identifi ed two patients with different outcome of infections who were infected with the same genotype of E. histolytica .…”

TheMAK16 Gene ofEntamoeba histolytica and Its Identification in Isolates from Patients

“…There are characteristic molecules involved in the virulence of the parasite, such as cysteine proteases, pore-forming proteins and lectins, which allow various activities, such as phagocytosis and tissue invasion [3,4]. It has been demonstrated that the inhibition of gene expression using antisense sequences blocks the production of molecules that can decrease virulence-altering cytopathic or cytotoxic events or phagocytosis [5,6,7,8]. However, blocking these cellular factors does not completely inhibit the pathogenicity of the protozoan.…”