Unknown,Transcriptomics,Genomics,Proteomics

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Towards an understanding of the mechanism of action of praziquantel

ABSTRACT: Although praziquantel (PZQ) has been used to treat schistosomiasis for over 20 years its mechanism of action remains unknown. We have developed an assay based on the transcriptional response of S. mansoni PR-1 to heat shock to confirm that while 6 week post infection (p.i.) schistosomes are sensitive to PZQ, 4 week p.i. schistosomes are not. Further, we have used this assay to demonstrate that this sensitivity develops between days 37 and 40 p.i. PZQ linked to the fluorophore BODIPY appears to easily enter the cells of intact 4 and 6 week p.i. schistosomes as well as mammalian NIH 3T3 cells and together, these data suggest that the differential effects of PZQ is not based on cell exclusion but probably due the differential expression of a target molecule at 6 weeks p.i. A transcriptomal analysis of gene expression between 4 and 6 weeks p.i. revealed 607 candidate genes whose products are potential PZQ targets. A comparison of this gene list with that of genes expressed by PZQ sensitive miracidia reduced this target list to 247 genes, including a number involved in aerobic metabolism and cytosolic calcium regulation. Finally, we also report the effect of an in vitro sub-lethal exposure of PZQ on the transcriptome of S. mansoni PR-1. Annotation of genes differentially regulated by PZQ exposure suggests that schistosomes may undergo a transcriptomic response similar to that observed during oxidative stress. Keywords: cell type comparison, time course Cell type comparison: Four biologial replactes of schistosomes harvasted 4 and 6 week post-infection were performed. Time course: Four samples performed in duplicate for exposure to a sub-lethal dose of PZQ (50 M-BM-5g/ml) at time points 0, 30, 60, and 240 min over a common reference sample.

ORGANISM(S): Schistosoma mansoni

SUBMITTER: Anthony Aragon

PROVIDER: E-GEOD-12850 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Towards an understanding of the mechanism of action of praziquantel.

Aragon Anthony D AD Imani Reza A RA Blackburn Vint R VR Cupit Pauline M PM Melman Sandra D SD Goronga Tinopiwa T Webb Thomas T Loker Eric S ES Cunningham Charles C

Molecular and biochemical parasitology 20081128 1

Although praziquantel (PZQ) has been used to treat schistosomiasis for over 20 years its mechanism of action remains unknown. We have developed an assay based on the transcriptional response of Schistosoma mansoni PR-1 to heat shock to confirm that while 6-week post-infection (p.i.) schistosomes are sensitive to PZQ, 4-week p.i. schistosomes are not. Further, we have used this assay to demonstrate that in mice this sensitivity develops between days 37 and 40 p.i. When PZQ is linked to the fluoro ...[more]

PMID: 19100294

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Project description:Schistosoma mansoni is one of the most common etiological agents responsible for the disease schistosomiasis. More than 200 million people suffer from this disease making it the most severe tropical disease after malaria in terms of morbidity. Praziquantel (PZQ) is the treatment of choice for schistosomiasis and has been used almost exclusively to treat the disease since the 1970s. However, while the drug is lethal for sexually mature schistosomes, it is ineffective against juveniles. Thus, while morbidity can be eased, a cure is difficult to achieve. As a result there is an urgent need to develop a new generation of anti-schistosomal drugs, a task that will be made easier by understanding the mechanism of action of PZQ. As yet, neither the molecule to which PZQ binds nor the means by which it kills mature schistosomes is known. The overarching aim of this study was to understand the molecular basis of PZQ sensitivity in S. mansoni. We believe that juvenile worms survive PZQ treatment in vivo due to the induction of, as yet, unidentified protective molecular pathways. To address this hypothesis juvenile and adult PR1 S. mansoni were treated in vitro with sub-lethal concentrations of PZQ. mRNA was extracted from replicate samples, cRNA prepagreen and labeled with cyanine dyes for analysis using a 44K S. mansoni microarray. The data was then analyzed using Genespring. Our findings suggest that a number of genes associated with drug transport, iron homeostasis and apoptosis are induced in juvenile but not adult schistosomes and that this allows the juvenile worms to protect themselves against the lethal effects of PZQ long enough for the drug to be metabolized by the human host. 42 days post exposure (DPE) male schistosomes were exposed to 0 and 1 µg/mL praziquantel (PZQ) for 1 or 20 h and 10 µg/mL PZQ for 1 h. 42 DPE female schistosomes were exposed to 0, 1 and 10 µg/mL PZQ for 20 h. 28 DPE mixed-sex schistosomes were exposed to 0, 1 and 10 µg/mL PZQ for 1 and 20 h. All experiments were performed in biological triplicates. The 0 µg/mL PZQ exposures were used as controls to the appropriate groups and a universal reference was used in all experiments that was comprised of RNA derived from 100 mixed sex, unexposed 42 DPE schistosomes spiked with 0.5 % (v/v) RNA isolated from 42 DPE mixed sex worms exposed to 10 µg/mL PZQ, 0.5 % (v/v) RNA isolated from 28 DPE worms exposed to 10 µg/mL PZQ and 0.5 % (v/v) RNA isolated from 28 DPE worms unexposed to PZQ. Transcriptional response to praziquantel exposure by time and concentration

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 platform previously designed by our group (PMID: 17517391) was used. 300 ng of RNA from adult schistosomes 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. 825 ng cRNA from each amplification were used for hybridization; self-self experiments were performed. 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). We calculated a virtual Log2 ratio between intensities of TNF-Î± Treated/Control, for each gene. With these ratios, we used two different approaches for SAM statistical analyses. SAM one-class approach was used to identify genes with sustained changes in their expression levels along the entire time period of observation (1 and 24 h); SAM two-class approach was used to identify genes with transient changes in their expression levels. In both cases, genes were considered 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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Towards an understanding of the mechanism of action of praziquantel

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Towards an understanding of the mechanism of action of praziquantel.

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