Schistosoma mansoni Tegument Protein Sm29 Is Able to Induce a Th1-Type of Immune Response and Protection against Parasite Infection

Schistosomiasis is the most important human helminth infection in terms of morbidity and mortality. Although the efforts to develop a vaccine against this disease have experienced failures, a new generation of surface antigens revealed by proteomic studies changed this scenario. Our group has characterized the protein Sm29 described previously as one of the most exposed and expressed antigens in the outer tegument of Schistosoma mansoni. Studies in patients living in endemic areas for schistosomiasis revealed high levels of IgG1 and IgG3 anti-Sm29 in resistant individuals. In this study, confocal microscope analysis showed Sm29 present in the surface of lung-stage schistosoluma and adult worms. Recombinant Sm29, when used as vaccine candidate, induced high levels of protection in mice. This protection was associated with a typical Th1 immune response and reduction of worm burden, liver granulomas and in intestinal eggs. Further, microarray analysis of worms recovered from vaccinated mice showed significant down-regulation of several genes encoding previously characterized vaccine candidates and/or molecules exposed on the surface, suggesting an immune evasion strategy of schistosomes under immune attack. These results demonstrated that Sm29 as one of the important antigens with potential to compose a vaccine against schistosomiasis

Interference with Hemozoin Formation Represents an Important Mechanism of Schistosomicidal Action of Antimalarial Quinoline Methanols

Heme is an essential molecule to most living organisms, but once in a free state it exerts toxic effects. Blood-feeding organisms evolved efficient ways to detoxify free heme derived from hemoglobin digestion. A key mechanism present in some hematophagous organisms consists of the crystallization of heme into a pigment named hemozoin. Schistosoma mansoni is one of the etiologic agents of human schistosomiasis, a parasitic disease that affects over 200 million people in tropical and subtropical areas. Hemozoin formation represents the main heme detoxification pathway in S. mansoni. Here, we report that the antimalarial quinoline methanols quinine and quinidine exert schistosomicidal effects notably due to their capacity to interfere with hemozoin formation. When quinine or quinidine were administered intraperitoneally during seven days to S. mansoni-infected mice (75 mg/kg/day), both worm and eggs burden were significantly reduced. Interestingly, hemozoin content in female worms was drastically affected after treatment with either compound. We also found that quinine caused important changes in the cellular organization of worm gastrodermis and increased expression of genes related to musculature, protein synthesis and repair mechanisms. Together, our results indicate that interference with hemozoin formation is a valid chemotherapeutic target for development of new schistosomicidal agents

Analysis of <it>Schistosoma mansoni </it>genes shared with Deuterostomia and with possible roles in host interactions

<p>Abstract</p> <p>Background:</p> <p><it>Schistosoma mansoni </it>is a blood helminth parasite that causes schistosomiasis, a disease that affects 200 million people in the world. Many orthologs of known mammalian genes have been discovered in this parasite and evidence is accumulating that some of these genes encode proteins linked to signaling pathways in the parasite that appear to be involved with growth or development, suggesting a complex co-evolutionary process.</p> <p>Results:</p> <p>In this work we found 427 genes conserved in the Deuterostomia group that have orthologs in <it>S. mansoni </it>and no members in any nematodes and insects so far sequenced. Among these genes we have identified Insulin Induced Gene (INSIG), Interferon Regulatory Factor (IRF) and vasohibin orthologs, known to be involved in mammals in mevalonate metabolism, immune response and angiogenesis control, respectively. We have chosen these three genes for a more detailed characterization, which included extension of their cloned messages to obtain full-length sequences. Interestingly, SmINSIG showed a 10-fold higher expression in adult females as opposed to males, in accordance with its possible role in regulating egg production. SmIRF has a DNA binding domain, a tryptophan-rich N-terminal region and several predicted phosphorylation sites, usually important for IRF activity. Fourteen different alternatively spliced forms of the <it>S. mansoni </it>vasohibin (SmVASL) gene were detected that encode seven different protein isoforms including one with a complete C-terminal end, and other isoforms with shorter C-terminal portions. Using <it>S. mansoni </it>homologs, we have employed a parsimonious rationale to compute the total gene losses/gains in nematodes, arthropods and deuterostomes under either the Coelomata or the Ecdysozoa evolutionary hypotheses; our results show a lower losses/gains number under the latter hypothesis.</p> <p>Conclusion:</p> <p>The genes discussed which are conserved between <it>S. mansoni </it>and deuterostomes, probably have an ancient origin and were lost in Ecdysozoa, being still present in Lophotrochozoa. Given their known functions in Deuterostomia, it is possible that some of them have been co-opted to perform functions related (directly or indirectly) to host adaptation or interaction with host signaling processes.</p

Analysis of genes shared with Deuterostomia and with possible roles in host interactions-2

<p><b>Copyright information:</b></p><p>Taken from "Analysis of genes shared with Deuterostomia and with possible roles in host interactions"</p><p>http://www.biomedcentral.com/1471-2164/8/407</p><p>BMC Genomics 2007;8():407-407.</p><p>Published online 8 Nov 2007</p><p>PMCID:PMC2194728.</p><p></p>ck gray bar at the top represents the genomic sequence of Supercontig_0000046. Coding sequences, UTRs and introns are represented by thick, thin and dashed lines, respectively. We have colored and numbered the different exons consecutively in an arbitrary way, in the order that each new exon splicing form appears in Figure 4A. Primers that were used for the RT-PCR amplification and RACE experiments of SmVASL alternatively spliced forms are represented by green and blue arrows, respectively. Deduced protein-coding ORFs of SmVASL message are represented by thick colored lines, and the lengths of the deduced encoded proteins are displayed at the right side of each splice variant. The asterisks next to SmVASLv6, SmVASLv6a and SmVASLv6b indicate that the latter two are the result of a 3'-RACE-PCR experiment (3'-RACE primers represented by blue arrows); : Local alignment (BLAST) showing the conserved region of SmVASLv6a and human vasohibin 2; : Agarose gel electrophoresis of RT-PCR products from a reaction performed with primers indicated in panel A with green arrows. indicates that cDNA was synthesized by Reverse Transcriptase with poly-dT priming using RNA as template, and PCR was subsequently performed. indicates a negative control where PCR was performed with an RNA sample incubated with poly-dT but no reverse transcriptase, to control for the absence of genomic DNA contamination

Analysis of genes shared with Deuterostomia and with possible roles in host interactions-5

<p><b>Copyright information:</b></p><p>Taken from "Analysis of genes shared with Deuterostomia and with possible roles in host interactions"</p><p>http://www.biomedcentral.com/1471-2164/8/407</p><p>BMC Genomics 2007;8():407-407.</p><p>Published online 8 Nov 2007</p><p>PMCID:PMC2194728.</p><p></p>ed yeast INSIG homologs were included in the MSA. SmINSIG transmembrane regions predicted by TMHMM and MINNOU are indicated by red and green bars, respectively. A consensus sequence and conservation bars are also represented; : Maximum Likelihood tree constructed from the alignment of SmINSIG and several INSIGs found in public databases. The branch is represented in red. Numbers next to the branches represent bootstrap values (in 1000 samplings)

Analysis of genes shared with Deuterostomia and with possible roles in host interactions-3

<p><b>Copyright information:</b></p><p>Taken from "Analysis of genes shared with Deuterostomia and with possible roles in host interactions"</p><p>http://www.biomedcentral.com/1471-2164/8/407</p><p>BMC Genomics 2007;8():407-407.</p><p>Published online 8 Nov 2007</p><p>PMCID:PMC2194728.</p><p></p>Maximum Likelihood tree constructed from the alignment of SmVASLv6a and other vasohibins found in public databases. The branch is represented in red. Numbers next to the branches represent bootstrap values (in 1000 samplings). : Real time RT-PCR using total RNA samples from egg, miracidium, cercaria, schistosomulum or adult and primers for SmVASL. Relative fold change was calculated by comparing the Ct value for each sample to Ct values for alpha-tubulin (internal standard)

Analysis of genes shared with Deuterostomia and with possible roles in host interactions-4

<p><b>Copyright information:</b></p><p>Taken from "Analysis of genes shared with Deuterostomia and with possible roles in host interactions"</p><p>http://www.biomedcentral.com/1471-2164/8/407</p><p>BMC Genomics 2007;8():407-407.</p><p>Published online 8 Nov 2007</p><p>PMCID:PMC2194728.</p><p></p>ly the conserved region is represented; : Maximum Likelihood tree constructed from the alignment of SmIRF and several IRFs found in public databases. The branch is represented in red. Numbers next to the branches represent bootstrap values (in 1000 samplings)

Analysis of genes shared with Deuterostomia and with possible roles in host interactions-0

<p><b>Copyright information:</b></p><p>Taken from "Analysis of genes shared with Deuterostomia and with possible roles in host interactions"</p><p>http://www.biomedcentral.com/1471-2164/8/407</p><p>BMC Genomics 2007;8():407-407.</p><p>Published online 8 Nov 2007</p><p>PMCID:PMC2194728.</p><p></p>ed yeast INSIG homologs were included in the MSA. SmINSIG transmembrane regions predicted by TMHMM and MINNOU are indicated by red and green bars, respectively. A consensus sequence and conservation bars are also represented; : Maximum Likelihood tree constructed from the alignment of SmINSIG and several INSIGs found in public databases. The branch is represented in red. Numbers next to the branches represent bootstrap values (in 1000 samplings)

Synergy of Omeprazole and Praziquantel <i>In Vitro</i> Treatment against <i>Schistosoma mansoni</i> Adult Worms

<div><p>Background</p><p>Treatment and morbidity control of schistosomiasis relies on a single drug, praziquantel (PZQ), and the selection of resistant worms under repeated treatment is a concern. Therefore, there is a pressing need to understand the molecular effects of PZQ on schistosomes and to investigate alternative or synergistic drugs against schistosomiasis.</p><p>Methodology</p><p>We used a custom-designed <i>Schistosoma mansoni</i> expression microarray to explore the effects of sublethal doses of PZQ on large-scale gene expression of adult paired males and females and unpaired mature females. We also assessed the efficacy of PZQ, omeprazole (OMP) or their combination against <i>S</i>. <i>mansoni</i> adult worms with a survival <i>in vitro</i> assay.</p><p>Principal Findings</p><p>We identified sets of genes that were affected by PZQ in paired and unpaired mature females, however with opposite gene expression patterns (up-regulated in paired and down-regulated in unpaired mature females), indicating that PZQ effects are heavily influenced by the mating status. We also identified genes that were similarly affected by PZQ in males and females. Functional analyses of gene interaction networks were performed with parasite genes that were differentially expressed upon PZQ treatment, searching for proteins encoded by these genes whose human homologs are targets of different drugs used for other diseases. Based on these results, OMP, a widely prescribed proton pump inhibitor known to target the ATP1A2 gene product, was chosen and tested. Sublethal doses of PZQ combined with OMP significantly increased worm mortality <i>in vitro</i> when compared with PZQ or OMP alone, thus evidencing a synergistic effect.</p><p>Conclusions</p><p>Functional analysis of gene interaction networks is an important approach that can point to possible novel synergistic drug candidates. We demonstrated the potential of this strategy by showing that PZQ in combination with OMP displayed increased efficiency against <i>S</i>. <i>mansoni</i> adult worms <i>in vitro</i> when compared with either drug alone.</p></div