Project description:Small RNA pyrosequencing in the protozoan parasite Entamoeba histolytica reveals strain-specific small RNAs that target virulence genes
Project description:Differential expression was used to access gene differences after Entamoeba histolytica infection. Entamoeba histolytica is an important diarrheal pathogen worldwide, and induces apoptosis of the intestinal epithelium as part of its disease process. Regenerating (REG) 1 protein is anti-apoptotic. We investigated the involvement of REG 1 in E. histolytica colitis. Colonic biopsy samples were obtained from 8 subjects with acute E. histolytica colitis, and again 60 day later during convalescence. Gene expression in the human colon during acute and convalescent E. histolytica disease was evaluated using microarray and confirmed by polymerase chain reaction (PCR). REG 1 protein expression was evaluated with immunohistochemistry. The mechanism of REG 1 involvement in E. histolytica disease was subsequently investigated with a mouse model. REG 1A and REG 1B were the most upregulated genes in the human intestine in acute versus convalescent E. histolytica disease (p=0.003 and p=0.006 respectively). PCR confirmed the microarray results (p=<0.001 and p=0.001 respectively). Increased REG 1A and REG 1B protein expression was similarly observed by immunohistochemistry. REG 1 -/-mice were found to be significantly more susceptible to E. histolytica infection than wild type mice.
Project description:We provided a full spectrum analysis for E. histolytica AGO2-2 associated 27nt small RNAs. Additionally, comparative analysis of small RNA populations from virulent and non-virulent amebic strains indicates that small RNA populations may regulate virulence genes.
Project description:Characterization of the human microbiota is providing new insightsinto the complexity of host–parasite–bacterium relationships. Amoebiasis (an intestinal infection affecting a large proportion of the population in many countries worldwide) is caused by the amoebic parasite Entamoeba histolytica. During amoebiasis, the parasite encounters several types of stress as a result of the host’s response to infection. Given that E. histolytica phagocytises bacteria in the intestinal lumen, we hypothesized that enteric bacteria can influence the course of an amoebic infection. Hence, we used live Escherichia coli O55 as a pertinent model of the bacterial community’s contribution to amoebic responses during host- induced stress. By measuring amoebic survival, we found that live E. coli protected E. histolytica against oxidative stress (OS) but not against nitrosative stress. E. coli– associated protection is correlated with massive transcriptionalchanges in amoebic genes acquired through lateral transfer from the bacterial kingdom, including genes coding for proteinscontaining leucine-rich repeat (LRR) motifs. The transcriptome profile triggered by OS and E. coli was also observed with other enteric bacteria, including pathogens and non-pathogens. In contrast, exposure to a probiotic resulted in a different transcriptome profile. The present study shows that OS and live bacteria together modulate 84 of E. histolytica’s 137 LRR protein genes. The LRR proteins are involvedin protein-ligand and protein-protein interactions – especially in proteins that interact with bacteria as part of the innate immune response in mammals and plants, such as Toll-like receptors. The structural and functional homology of LRRs and TLRs identified here suggest that despite its old age in evolutionary terms, the protozoan E. histolytica displays key characteristics of higher eukaryotes’ innate immune systems. We conclude that components of innate immunity existed in the common ancestor of plants and animals
Project description:We provided a full spectrum analysis for E. histolytica AGO2-2 associated 27nt small RNAs. Additionally, comparative analysis of small RNA populations from virulent and non-virulent amebic strains indicates that small RNA populations may regulate virulence genes. AGO2-2 bound small RNAs from E. histolytica strain HM-1:IMSS were immunoprecipitated and sequenced using 454 technology. Three independant sequencing runs were perfomed using the same RNA sample. In addition, size selected small RNAs from E. histolytica strain Rahman were sequenced with the same technology. One sequencing run was performed on this sample.
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:Entamoeba histolytica is a human pathogen, responsible for amoebic dysentery and invasive extraintestinal disease. The parasite faces several types of stress within the host, and to establish a successful infection it must generate a robust adaptive response against host defense mechanisms. In order to obtain comprehensive information of gene expression changes in E. histolytica under growth stress, we have (1) optimized the proteomics protocol to increase the protein coverage in E. histolytica, and (2) integrated proteomic data with transcriptomic analysis under the same conditions. We have applied this approach to better understand the cellular response during serum-starvation. Label-free quantitative proteomics was performed, and compared with mRNA levels based on RNA-seq data to decipher regulation at translational and transcriptional levels. Across all samples, 2344 proteins were identified, which is an improvement over the maximum recorded number in E. histolytica proteomic studies so far. A total of 127 proteins were found to be differentially expressed and associated with functions including antioxidant activity, cytoskeleton, translation, catalysis, and transport, which revealed proteomic signatures to distinguish serum-starved from normal trophozoites. Gal/GalNAc-inhibitable lectin, Lgls, Hgl3 and Igl were repeatedly identified as significantly altered in serum-stress condition. Further, integration of transcriptomic and proteomic data revealed instances of post-transcriptional regulation. Six highly expressed transcripts had low corresponding protein expression, indicating translational repression. Conversely, eleven transcripts showed much greater downregulation compared with their corresponding proteins, indicating translational induction, or increased stability of these proteins during serum stress in E. histolytica. This multi-omics approach enables more refined gene expression analysis that would not be possible at the mRNA or protein levels alone. Our study provides important data to further understand the adaptive response of E. histolytica to growth stress.