The role of queuine as a nutritional regulator of the response of Entamoeba histolyticato oxidative stress
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ABSTRACT:
PROVIDER: PRJNA596228 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR10721174.fastq.gz | Fastqsanger.gz | |||
| SRR10721175.fastq.gz | Fastqsanger.gz | |||
| SRR10721176.fastq.gz | Fastqsanger.gz | |||
| SRR10721177.fastq.gz | Fastqsanger.gz | |||
| SRR10721178.fastq.gz | Fastqsanger.gz |
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Project description:Amebiasis is an intestinal disease transmitted by the protist parasite, Entamoeba histolytica, following the ingestion of contaminated food and water. Many infected patients (90%) are asymptomatic but for unknown reasons, these trophozoites can become virulent and invasive, cause amebic dysentery, and migrate to the liver, via the portal veins, where they cause hepatocellular damage. We have recently reported that Escherichia coli can modulate E.histolytica 's virulence and resistance to oxidative stress (OS) via the production of oxaloacetate. Queuosine is a naturally occurring modified nucleoside and is found in the first position of the anticodon of the transfer RNAs for Asp, Asn, His and Tyr. Lower and higher eukaryotes are supplied with queuine (the base of queuosine) in the diet or by the intestinal flora. Here, we have tested the hypothesis that queuine being a micronutrient offers an advantage to E.histolytica during OS. Queuine which is efficiently incorporated in E.histolytica’s tRNAs leads to significant modifications of the parasite’s transcriptome, to hypermethylation of C38 in tRNAAspGTC and consequently to OS resistance. While queuine leads to the translation of proteins during OS, we found that that it inhibits protein synthesis otherwise. Localization studies with an antibody against EhTGT in queuine-treated trophozoites revealed the presence of small granular structures. We have biochemically characterized the parasite’s tRNA-guanine transglycosylase (TGT), the enzyme that catalyzes the modification of Q-tRNAs. Trophozoites silenced for TGT expression have a growth defect and they are less resistant to OS compared to control trophozoites.
2021-02-18 | GSE142211 | GEO
Project description:Enteric bacteria increase the defenses against oxidative stress in Entamoeba histolytica
| PRJNA412624 | ENA
Project description:Queuosine is a naturally occurring modified ribonucleoside found in the first position of the anticodon of the transfer RNAs for Asp, Asn, His, and Tyr. Eukaryotes lack pathways to synthesize queuine, the nucleobase precursor to queuosine, and must obtain it from diet or gut microbiota. Here, we describe the effects of queuine on the physiology of the eukaryotic parasite Entamoeba histolytica, the causative agent of amebic dysentery. Queuine is efficiently incorporated into E. histolytica tRNAs by a tRNA-guanine transglycosylase (EhTGT) and this incorporation stimulates the methylation of C38 in [Formula: see text] Queuine protects the parasite against oxidative stress (OS) and antagonizes the negative effect that oxidation has on translation by inducing the expression of genes involved in the OS response, such as heat shock protein 70 (Hsp70), antioxidant enzymes, and enzymes involved in DNA repair. On the other hand, queuine impairs E. histolytica virulence by downregulating the expression of genes previously associated with virulence, including cysteine proteases, cytoskeletal proteins, and small GTPases. Silencing of EhTGT prevents incorporation of queuine into tRNAs and strongly impairs methylation of C38 in [Formula: see text], parasite growth, resistance to OS, and cytopathic activity. Overall, our data reveal that queuine plays a dual role in promoting OS resistance and reducing parasite virulence.IMPORTANCEEntamoeba histolytica is a unicellular parasite that causes amebiasis. The parasite resides in the colon and feeds on the colonic microbiota. The gut flora is implicated in the onset of symptomatic amebiasis due to alterations in the composition of bacteria. These bacteria modulate the physiology of the parasite and affect the virulence of the parasite through unknown mechanisms. Queuine, a modified nucleobase of queuosine, is exclusively produced by the gut bacteria and leads to tRNA modification at the anticodon loops of specific tRNAs. We found that queuine induces mild oxidative stress resistance in the parasite and attenuates its virulence. Our study highlights the importance of bacterially derived products in shaping the physiology of the parasite. The fact that queuine inhibits the virulence of E. histolytica may lead to new strategies for preventing and/or treating amebiasis by providing to the host queuine directly or via probiotics.
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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
2018-06-08 | GSE104434 | GEO
Project description:Campylobacter jejuni is the leading bacterial cause of human gastroenteritis worldwide. Despite stringent microaerobic growth requirements, C. jejuni is ubiquitous in the aerobic environment. C. jejuni must possess finely tuned regulatory systems to sense and adapt to external stimuli such as oxidative and aerobic (O2) stress. Re-annotation of the C. jejuni NCTC11168 genome sequence identified Cj1556 (originally annotated as a hypothetical protein) as a MarR family transcriptional regulator and further bioinformatic analysis indicated a role in regulating the oxidative stress response. A C. jejuni 11168H Cj1556 mutant exhibited increased sensitivity to oxidative and aerobic stress, decreased ability for intracellular survival in both Caco-2 human intestinal epithelial cells and J774A.1 mouse macrophages and a reduction in virulence in the Galleria mellonella infection model. Microarray analysis of gene expression changes in the Cj1556 mutant compared to the wild-type strain indicated negative autoregulation of Cj1556 expression and down-regulation of genes associated with oxidative and aerobic stress responses, such as katA, perR and hspR. cprS, which encodes a sensor kinase involved in the regulation of biofilm formation, was also up-regulated in the Cj1556 mutant and subsequent studies showed that the Cj1556 mutant had a reduced ability to form biofilms. Protein interaction studies confirmed the binding of recombinant Cj1556 to a region upstream of Cj1556. This study has identified a novel C. jejuni transcriptional regulator Cj1556 that is involved in oxidative and aerobic stress responses and is important for the survival of C. jejuni in the natural environment and in vivo. This newly identified regulator was designated CosR (Campylobacter oxidative stress Regulator). Data is also available from <ahref=""http://bugs.sgul.ac.uk/E-BUGS-119"" target=""_blank"">BuG@Sbase</a>
2012-01-23 | E-BUGS-119 | biostudies-arrayexpress
Project description:BACH1, the master regulator of oxidative stress, modulates CFTR gene expression
| PRJNA695525 | ENA
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.
2011-05-24 | GSE23750 | GEO
Project description:Entamoeba histolytica is a protozoan parasite which causes colitis and liver abscesses. Using a genomic DNA microarray consisting of 1.6 - 2.0 kb genomic inserts we have generated a transcriptional profile of 1,971 unique parasite transcripts. The arrays in this experiment set were used to (1) estimate relative transcript abundance for Entamoeba histolytica (HM-1:IMSS) trophozoites in mid-logarithmic growth and (2) to examine changes in the transcriptional profile of Entamoeba histolytica when the parasite interacts with colonic epithelial cells (Caco-2). A time course was used such that RNA was isolated from ameba alone and ameba + Caco-2 cells at 3hrs, 6hrs and 9hrs corresponding to 10%, 50% and 90% cell monolayer destruction. At least two biological experiments and three replicates were used for each time point. Groups of assays that are related as part of a time series. Keywords: time_series_design
2005-07-22 | GSE2979 | GEO