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Interleukin-4-inducing principle from Schistosoma mansoni eggs contains a functional C-terminal nuclear localization signal necessary for nuclear translocation in mammalian cells but not for its uptake.

ABSTRACT: Interleukin-4-inducing principle from schistosome eggs (IPSE/alpha-1) is a protein produced exclusively by the eggs of the trematode Schistosoma mansoni. IPSE/alpha-1 is a secretory glycoprotein which activates human basophils via an IgE-dependent but non-antigen-specific mechanism. Sequence analyses revealed a potential nuclear localization signal (NLS) at the C terminus of IPSE/alpha-1. Here we show that this sequence (125-PKRRRTY-131) is both necessary and sufficient for nuclear localization of IPSE or IPSE-enhanced green fluorescent protein (EGFP) fusions. While transiently expressed EGFP-IPSE/alpha-1 was exclusively nuclear in the Huh7 and U-2 OS cell lines, a mutant lacking amino acids 125 to 134 showed both nuclear and cytoplasmic staining. Moreover, insertion of the IPSE/alpha-1 NLS into a tetra-EGFP construct rendered the protein nuclear. Alanine scanning mutagenesis revealed a requirement for the KRRR residues. Fluorescence microscopy depicted, and Western blotting further confirmed, that recombinant IPSE/alpha-1 protein added exogenously is rapidly internalized by CHO cells and accumulates in nuclei in an NLS-dependent manner. A mutant protein in which the NLS motif was disrupted by triple mutation (RRR to AAA) was able to penetrate CHO cells but did not translocate to the nucleus. Furthermore, the uptake of native glycosylated IPSE/alpha-1 was confirmed in human primary monocyte-derived dendritic cells and was found to be a calcium- and temperature-dependent process. Live-cell imaging showed that IPSE/alpha-1 is not targeted to lysosomes. In contrast, peripheral blood basophils do not take up IPSE/alpha-1 and do not require the presence of an intact NLS for activation. Taken together, our results suggest that IPSE/alpha-1 may have additional nuclear functions in host cells.

SUBMITTER: Kaur I

PROVIDER: S-EPMC3067533 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature

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Interleukin-4-inducing principle from Schistosoma mansoni eggs contains a functional C-terminal nuclear localization signal necessary for nuclear translocation in mammalian cells but not for its uptake.

Kaur Ishwinder I Schramm Gabriele G Everts Bart B Scholzen Thomas T Kindle Karin B KB Beetz Christian C Montiel-Duarte Cristina C Blindow Silke S Jones Arwyn T AT Haas Helmut H Stolnik Snjezana S Heery David M DM Falcone Franco H FH

Infection and immunity 20110110 4

Interleukin-4-inducing principle from schistosome eggs (IPSE/alpha-1) is a protein produced exclusively by the eggs of the trematode Schistosoma mansoni. IPSE/alpha-1 is a secretory glycoprotein which activates human basophils via an IgE-dependent but non-antigen-specific mechanism. Sequence analyses revealed a potential nuclear localization signal (NLS) at the C terminus of IPSE/alpha-1. Here we show that this sequence (125-PKRRRTY-131) is both necessary and sufficient for nuclear localization ...[more]

PMID: 21220486

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Project description:Background & aimsSchistosomiasis is a parasitic infection which affects more than 200 million people globally. Schistosome eggs, but not the adult worms, are mainly responsible for schistosomiasis-specific morbidity in the liver. It is unclear if S. mansoni eggs consume host metabolites, and how this compromises the host parenchyma.MethodsMetabolic reprogramming was analyzed by matrix-assisted laser desorption/ionization mass spectrometry imaging, liquid chromatography with high-resolution mass spectrometry, metabolite quantification, confocal laser scanning microscopy, live cell imaging, quantitative real-time PCR, western blotting, assessment of DNA damage, and immunohistology in hamster models and functional experiments in human cell lines. Major results were validated in human biopsies.ResultsThe infection with S. mansoni provokes hepatic exhaustion of neutral lipids and glycogen. Furthermore, the distribution of distinct lipid species and the regulation of rate-limiting metabolic enzymes is disrupted in the liver of S. mansoni infected animals. Notably, eggs mobilize, incorporate, and store host lipids, while the associated metabolic reprogramming causes oxidative stress-induced DNA damage in hepatocytes. Administration of reactive oxygen species scavengers ameliorates these deleterious effects.ConclusionsOur findings indicate that S. mansoni eggs completely reprogram lipid and carbohydrate metabolism via soluble factors, which results in oxidative stress-induced cell damage in the host parenchyma.Impact and implicationsThe authors demonstrate that soluble egg products of the parasite S. mansoni induce hepatocellular reprogramming, causing metabolic exhaustion and a strong redox imbalance. Notably, eggs mobilize, incorporate, and store host lipids, while the metabolic reprogramming causes oxidative stress-induced DNA damage in hepatocytes, independent of the host's immune response. S. mansoni eggs take advantage of the host environment through metabolic reprogramming of hepatocytes and enterocytes. By inducing DNA damage, this neglected tropical disease might promote hepatocellular damage and thus influence international health efforts.

Project description:Protein variation in blood-dwelling schistosome worms generated by differential splicing of micro-exon gene transcripts. The infective schistosome cercaria develops from an undifferentiated germ ball within the daughter sporocyst in the molluscan host, during which considerable morphological development and synthesis of proteins essential for infection occurs. The free-living, non-feeding cercaria is notable for its swimming and host location behaviour. On contact with host skin it rapidly penetrates, replaces its tegument surface membranes, and begins body remodelling, before crossing the dermis to exit the skin via a blood vessel. Such a ‘violent’ transition from snail to fresh water to mammalian host should be accompanied by remarkable changes in the patterns of gene expression. All gene models from version E of the S. mansoni genome (www.GeneDB.org) were incorporated into a 350K feature Roche-NimbleGen, high-density oligonucleotide array. From a map-ordered list, every 13th 50mer was chosen as a probe. Double-stranded cDNA from three biological replicates each of germ balls, cercariae, and day 3 schistosomula was hybridised to the array without amplification. Statistical analysis was carried out using programmes from the Bioconductor suite (Gentleman et al. 2004 Genome Biol 5(10):R80). More than 1000 loci were shown to be differentially expressed in each of the comparisons between the three life cycle stages. Gene ontology (GO) analysis was then carried out to discover the categories enriched in each stage. In addition custom categories based on biological function (e.g. stress response) or parasite tissue (e.g. tegument) were analysed. Three biological replicates each of germ balls, cercariae, day 3 in vitro cultured schistosomula, and eggs were used. No technical replicates were included. This is the first genome-wide microarray platform for S. mansoni. It was used to investigate the gene expression patterns of the above lifecycle stages. The first three are the stages before, during and after penetration of mammalian host skin.

Dataset Information

Interleukin-4-inducing principle from Schistosoma mansoni eggs contains a functional C-terminal nuclear localization signal necessary for nuclear translocation in mammalian cells but not for its uptake.

Publications

Interleukin-4-inducing principle from Schistosoma mansoni eggs contains a functional C-terminal nuclear localization signal necessary for nuclear translocation in mammalian cells but not for its uptake.

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