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.
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
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
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).
Project description:Entamoeba histolytica is a protozoan parasite that causes colitis and liver abscesses. Several Entamoeba species and strains with differing levels of virulence have been identified. E. histolytica HM-1:IMSS is a virulent strain, E. histolytica Rahman is a nonvirulent strain, and Entamoeba dispar is a nonvirulent species. We used an E. histolytica DNA microarray consisting of 2,110 genes to assess the transcriptional differences between these species/strains with the goal of identifying genes whose expression correlated with a virulence phenotype. We found 415 genes expressed at lower levels in E. dispar and 32 genes with lower expression in E. histolytica Rahman than in E. histolytica HM-1:IMSS. Overall, 29 genes had decreased expression in both the nonvirulent species/strains than the virulent E. histolytica HM-1:IMSS. Interestingly, a number of genes with potential roles in stress response and virulence had decreased expression in either one or both nonvirulent Entamoeba species/strains. These included genes encoding Fe hydrogenase (9.m00419), peroxiredoxin (176.m00112), type A flavoprotein (6.m00467), lysozyme (6.m00454), sphingomyelinase C (29.m00231), and a hypothetical protein with homology to both a Plasmodium sporozoite threonine-asparagine-rich protein (STARP) and a streptococcal hemagglutinin (238.m00054). The function of these genes in Entamoeba and their specific roles in parasite virulence need to be determined. We also found that a number of the non-long-terminal-repeat retrotransposons (EhLINEs and EhSINEs), which have been shown to modulate gene expression and genomic evolution, had lower expression in the nonvirulent species/strains than in E. histolytica HM-1:IMSS. Our results, identifying expression profiles and patterns indicative of a virulence phenotype, may be useful in characterizing the transcriptional framework of virulence.
Project description:Amebiasis is a parasitic infection of the human intestines, primarily caused by Entamoeba histolytica. Its pathogenesis relies on the environmental sensing-induced cytoskeletal remodeling as the basic mechanism for motility and tissue invasion. We identified and characterized a G protein-coupled receptor-like protein, EhGPCR (CL6EHI_096680), predicted to contain a Venus Fly-Trap (VFT) extracellular domain with an Atrial Natriuretic Factor (ANF) receptor domain, as commonly found in the class C GPCR family protein. This protein is uniquely lacking a transmembrane domain. Instead, the glycosylphosphatidylinositol (GPI) anchor is responsible for its cell membrane localization. Removal of the GPI signal led to unexpected mitosomal localization, highlighting the importance of GPI modification in subcellular targeting. Functional studies revealed that EhGPCR knockdown reduced parasite motility and phagocytosis following the reduction of expression of actin cytoskeleton-related genes, including myosin II, villidin, and gelsolin. Our findings suggest that EhGPCR (CL6EHI_096680) plays a role in regulating downstream signaling linked to Entamoeba motility and phagocytosis. This study provides novel insights into GPCR-like signaling in E. histolytica, an area previously understudied.
Project description:The enteric protozoan parasite Entamoeba histolytica have high phagocytic ability. Phagocytosis is also important for the pathogenicity of this parasite; molecular mechanisms of phagocytosis and phagosome maturation is focused. Atg8 is well studied autophagy marker protein. We previously shown that E. histolytica Atg8 translocate to nascent trogosomes and expression silencing of the Atg8 caused retardation of phagosome acidification. To investigate how Atg8 regulates phagosome maturation, here we conducted proteome analysis of phagosomes isolated from an E. histolytica strain in which atg8 gene expression are silenced (atg8 gene silenced, atg8-gs) and its mock control strain (transfected with psAP2-Gunma).