Unknown,Transcriptomics,Genomics,Proteomics

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Transcription profiling of Schistosoma mansoni lung schistosomulum

ABSTRACT: The lung schistosomulum of Schistosoma mansoni is a validated target of protective immunity elicited in vaccinated mice. To identify genes expressed at this stage we constructed a microarray, representing 3088 contigs and singlets, with cDNA derived from in vitro cultured larvae, and used it to screen RNA from seven life cycle stages. Clustering of genes by expression profile across the life cycle revealed a number of membrane, membrane-associated and secreted proteins up-regulated at the lung stage, that may represent potential immune targets. Two promising secreted molecules have homlogy to antigens with vaccine and/or immunomodulatory potential in other helminths.

ORGANISM(S): Schistosoma mansoni

SUBMITTER: Matloob Qureshi

PROVIDER: E-SGRP-2 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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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.

Project description:Schistosoma mansoni is the major causative agent of schistosomiasis in the Americas. This parasite takes advantage from host signaling molecules such as cytokines and hormones to complete its development inside the host. TNF-Î± is the most important cytokine involved in the inflammatory response when cercaria, the infective stage, penetrates the human skin and a severe inflammatory response is started. In this work the authors describe the complete sequence of a possible TNF-Î± receptor in S. mansoni and detect that the receptor is most highly expressed in cercaria among all life cycle stages. In an attempt to mimic the situation at the site of skin penetration cercariae have been mechanically transformed in vitro into schistosomula and immediately exposed to human TNF-Î± . Exposure of these early schistosomula to the human hormone caused a large-scale change in the expression of parasite genes. Exposure of adult worms to human TNF-Î± caused gene expression changes as well, although the set of parasite altered genes was entirely different from that of schistosomula. This work increases the number of known signaling pathways of the parasite, and opens new perspectives into understanding the molecular components of TNF-Î± response as well as possibly interfering with parasite-host interaction. A 4 x 44k microarray platform was designed with the same probe set described by our group in a previous publication (PMID: 17517391). 230 ng of RNA from schistosomula treated with TNF and its control were used for the hybridization. RNA amplification and labeling kit (Agilent Technologies) were used according to manufacturerÂ´s instructions. Each sample was separately labeled with either Cy3 or Cy5 and 825 ng cRNA from each amplification were used for hybridization a control sample was combined with a treated sample and hybridized. Washing and scanning procedures were according to the manufacturerÂ´s instructions using GenePix 4000B scanner (Molecular Devices, Sunnyvale, CA, USA). Data was extracted using Feature Extraction software (Agilent Technologies). Low intensity data points were filtered out according to Feature Extraction software criteria, which essentially determine those points that are significantly below the average background signal of the array. Total intensity data from each experiment were normalized by Quantiles Normalization Method, excluding positive and negative external controls. Significance Analysis of Microarray (SAM) was used as to find differentially expressed genes. z-score transformation of normalized data was performed and SAM two class tests were applied; genes were considered as significantly differentially expressed at q-value â¤ 0.05. Hierarchical clustering of selected genes was generated using Spotfire Decision Site software (TIBCO Software Inc., Palo Alto, CA, USA). For a gene that was represented in the array by multiple probes, we picked a single representative probe by selecting the probe with the highest absolute value of the Log2 ratio between intensities of TNF-Î± Treated/Control.

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Transcription profiling of Schistosoma mansoni lung schistosomulum

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