Expression of virulent and non-virulent E.histolytica in contact with the human colon
Ontology highlight
ABSTRACT:
ORGANISM(S): Entamoeba histolytica
SUBMITTER: Christian Weber
PROVIDER: E-MTAB-1201 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:The main goal of this study was to analyse gene expression change of virulent amoebic strain (i.e. HM1:IMSS) in different environmental contexts, including isolation from animal liver, contact with the human colon and short prolonged in vitro culture.
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Project description:Amoebiasis is a disease caused by the protozoan parasite, Entamoeba histolytica, with or without clinical symptoms . It has been suggested that pathogenic amoebae use three major virulence factors: Gal/GalNAc lectin, cysteine proteinases and amoebapores. However, these molecules cannot exclusively be responsible for amoebic virulence, because most of them are found in pathogenic E. histolytica as well as in non-pathogenic E. dispar, a not close correlation has been found in amoebic strains with different virulence phenotype. Due to the high genetic variability of E. histolytica isolates and strains, differential gene expression might simply reflect inter-isolate genetic variation rather than specific differences linked to virulence. In the current study, we obtained a non-virulent UG10 mutant derived from E. histolytica HM-1:IMSS. Comparing the transcriptome of both strains, no differences in gene expression of the classical virulence factors were observed. RAB family GTPase and AIG1 family members showed higher transcriptional levels in the virulent strain than in the non-virulent mutant. Our study suggests a number of novel gene products in E. histolytica with a role yet to determine in cell physiology and involvement in the pathogenesis process.
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Project description:The ability of Entamoeba histolytica to phagocytose host cells correlates to observed virulence in vivo. To better understand the mechanism of phagocytosis we used paramagnetic beads coated with host ligand and sorted trophozoites based on phagocytic ability. Gene expression was then measured in both the sorted phagocytic and non-phagocytic populations using a custom Affymetrix chip for E. histolytica. Feed forward regulation of phagocytosis by Entamoeba histolytica. Infection and Immunity. PMID 23045476 M280 Streptavidin Dynabeads (Invitrogen) were labeled with 20ug/mL biotinylated Human C1q (Quidel). Entamoeba histolytica (strain HM1) were washed twice with PBS then resuspended with the labeled beads at a 10:1 ratio of beads to trophozoites. Samples were incubated at 37°C for 45 minutes, washed twice with agitation to remove adherent beads, then resuspended in MACS buffer. Samples were loaded into magnetic columns (Miltenyi Biotec) and trophozoites were seperated according to manufacturer's protocols. phagocytic vs. non-phagocytic Entamoeba histolytica populations
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Project description:Entamoeba histolytica is the parasite causing amoebiasis, an infectious disease targeting the intestine and liver of humans. The molecules involved in amoeba adaptation to different iron conditions during the invasive process are unknown. To investigate the effects of iron availability on gene expression in E. histolytica, we determined by microarray experiments the gene expression profile of parasites grown in the presence of different iron concentrations. Conditions included low amounts of iron, iron starvation and iron starvation supplemented with hemoglobin (Hb). Genes encoding important proteins involved in iron metabolism, reported in other organism such as bacteria, were identified for the first time in E. histolytica. The influence of iron on the amount of these transcripts was confirmed by quantitative real-time PCR and their protein products were analyzed by Western blots
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Project description:Entamoeba histolytica contains a large and novel family of transmembrane kinases (TMK) with proposed roles that include both amebic response to the environment and immune evasion. In the later case, the process requires several elements --these include a large gene family encoding antigenically distinct surface proteins and the expression of one variant antigen at a time by a single pathogen. Laser-capture microdissection was used in conjunction with microarray analysis to demonstrate that single trophozoites express more than one TMK gene. Overall, our data indicates that multiple members of the novel E. histolytica TMK family are utilized for non-redundant functions by the parasite. For laser capture microdissection analysis, harvested trophozoites were allowed to adhere to metal framed PEN membrane slides (Molecular Devices, Sunnyvale, CA) for 15 mins at 37°C in TYI-S-33 media. Subsequently, single cells were captured from the PEN slides using a Pix Cell II laser capture microdissection system equipped with an Olympus microscope (Arcturus Engineering, Mountain View, CA).
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2015-03-02 | E-MTAB-1207 | biostudies-arrayexpress
Project description:We previously showed that epigenetic transcriptional silencing of the amoebapore gene (Ehap-a) in E. histolytica G3 trophozoites was accompanied by the down-regulation of two other members of the saposin-like gene family (Ehap-b, and EhSaplip1). Comparison of the transcriptomes of G3 trophozoites with those of the parent HM-1:IMSS strain revealed 72 additional transcripts that were either down- or up-regulated at least 7 fold. One of the polyA+, up-regulated (>200) transcripts (459.m00030), had the potential to encode a 66 amino acid protein. Antibodies raised against a synthetic N-terminal peptide of the gene did not recognize any such protein in trophozoite lysates. Trophozoite cultures grown with the proteasome inhibitor MG-132 to prevent protein degradation, also did not have any detectable protein. Transfections with a plasmid in which the Ehactin gene promoter elements were used to flank the 459.m gene, significantly increased their level transcript but again, no protein was detected. Transfectants in which the 459.m ORF was placed downstream to the GST gene, expressed a fused protein which reacted with the antibody against the m.459 peptide. Constructs with the CAT reporter gene placed under the 459.m gene promoter element or fused to the C-terminal sequence of the 459.m ORF were prepared to determine if the higher levels of 459.m transcript found in the G3 trophozoites were due to changes in the stability of the transcript or increased transcription. No difference was observed in the very weak expressions seen in both G3 and HM-1:IMSS transfectants. Similarly, transfectants with a plasmid construct in which the 459.m gene was placed under its regulatory elements, did not induce an increase in the transcript levels. Our conclusions are that the transcript of the 459.m gene is an mRNA-like ncRNA and that modulations of transcript levels, especially of hypothetical genes, may not correlate with changes in the proteome. Samples include two replicates of the HM-1:IMSS strain and the amoebapore a silenced G3 strain (G3(A))
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Project description:Resistance to amebiasis is associated with a polymorphism in the leptin receptor. Previous studies demonstrated that humans with the ancestral Q223 leptin receptor allele were nearly four times less likely to be infected with Entamoeba histolytica than those carrying the mutant R223 allele. We hypothesized that the Q223 allele protected against E. histolytica via STAT3-mediated transcription of genes required for mucosal immunity. To test this, mice containing the humanized LEPR Q or R allele at codon 223 were intracecally infected with E. histolytica. Susceptibility to amebiasis was assessed, and cecal tissues analyzed for changes in gene expression. By 72 h post-challenge all Q223 mice had cleared E. histolytica, whereas 39% of 223R mice were infected. 37 genes were differentially expressed in response to infection at 72 h, including pro-inflammatory genes (CXCL2, calprotectin (S100A8/9), Pla2g7, Itbg2, and MMP9) and functions pertaining to the movement and activity of immune cells. A comparison at 12 h post-challenge of infected Q223 vs. R223 mice identified a subset of differentially-expressed genes, many of which were closely linked to leptin signaling. Further analyses indicated that the Q223 gene expression pattern was consistent with a suppressed apoptotic response to infection, while 223R showed increased cellular proliferation and recruitment. These studies are the first to illuminate the downstream effects of leptin receptor polymorphisms on intestinal infection by E. histolytica. As such, they are important for the insight that they provide to this previously uncharacterized mechanism of mucosal immunity. Resistance to amebiasis is associated with a polymorphism in the leptin receptor. Previous studies demonstrated that humans with the ancestral Q223 leptin receptor allele were nearly four times less likely to be infected with Entamoeba histolytica than those carrying the mutant R223 allele. We hypothesized that the Q223 allele protected against E. histolytica via STAT3-mediated transcription of genes required for mucosal immunity. To test this, mice containing the humanized LEPR Q or R allele at codon 223 were intracecally infected with E. histolytica. Susceptibility to amebiasis was assessed, and cecal tissues analyzed for changes in gene expression. By 72 h post-challenge all Q223 mice had cleared E. histolytica, whereas 39% of 223R mice were infected. 37 genes were differentially expressed in response to infection at 72 h, including pro-inflammatory genes (CXCL2, calprotectin (S100A8/9), Pla2g7, Itbg2, and MMP9) and functions pertaining to the movement and activity of immune cells. A comparison at 12 h post-challenge of infected Q223 vs. R223 mice identified a subset of differentially-expressed genes, many of which were closely linked to leptin signaling. Further analyses indicated that the Q223 gene expression pattern was consistent with a suppressed apoptotic response to infection, while 223R showed increased cellular proliferation and recruitment. These studies are the first to illuminate the downstream effects of leptin receptor polymorphisms on intestinal infection by E. histolytica. As such, they are important for the insight that they provide to this previously uncharacterized mechanism of mucosal immunity. Control (non-infected QQ or RR) vs. infected with E. histolytica at two time points (12hour and 72 hour)
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