Tissue Specific Profiling of Females of Schistosoma japonicum by Integrated Laser Microdissection Microscopy and Microarray Analysis

Schistosomes are parasitic worms responsible for important human diseases in tropical and developing nations. There is urgent need to develop new drugs and vaccines to augment current treatments for this disease. In recent years, concerted efforts by many laboratories have led to extensive genetic sequencing of the parasites, and the publication of genome sequence for two agents of schistosomiasis appears imminent. This genetic information has revealed many molecules expressed by the schistosome parasites for which no functional information is available. This lack of information extends to ignorance of where in the complex multicellular schistosome parasites the genes are expressed. We integrated two molecular and cellular techniques to address these knowledge gaps. We used laser microdissection microscopy to dissect small but highly important tissues involved in nutrition and reproduction from sections of female Schistosoma japonicum. From these dissected tissues we then used a broad molecular biology method to identify the multiple genes active in these tissues. Our approach has allowed us to formulate the basis of a “gene atlas” for schistosome parasites, defining the expression repertoire of specific tissues. The better understanding of the roles of tissues in parasite biology, especially in development, reproduction and interactions with its human hosts, should promote future investigations into pathogenesis and control of these significant parasites

Transcriptional profiling of the oesophageal gland region of male worms of Schistosoma mansoni

The intestinal tract of schistosomes opens at the mouth and leads into the foregut or oesophageal region that is lined with syncytium continuous with the apical cytoplasm of the tegument. The oesophagus is surrounded by a specialised gland, the oesophageal gland. This gland releases materials into the lumen of the oesophagus and the region is thought to initiate the lysis of erythrocytes and neutralisation of immune effectors of the host. The oesophageal region is present in the early invasive schistosomulum, a stage potentially targetable by anti-schistosome vaccines. We used a 44k oligonucleotide microarray to identify highly up-regulated genes in microdissected frozen sections of the oesophageal gland of male worms of S. mansoni. We show that 122 genes were up-regulated 2-fold or higher in the oesophageal gland compared with a whole male worm tissue control. The enriched genes included several associated with lipid metabolism and transmembrane transport as well as some micro-exon genes. Since the oesophageal gland is important in the initiation of digestion and the fact that it develops early after invasion of the mammalian host, further study of selected highly up-regulated functionally important genes in this tissue may reveal new anti-schistosome intervention targets for schistosomiasis control. (C) 2014 Elsevier B.V. All rights reserved

Gene expression in developmental stages of Schistosoma japonicum provides further insight into the importance of the Schistosome insulin-like peptide

We showed previously that the Schistosoma japonicum insulin-like peptide (SjILP) binds the worm insulin receptors, thereby, activating the parasite's insulin pathway and emphasizing its important role in regulating uptake of glucose, a nutrient essential for parasite survival. Here we show that SjILP is differentially expressed in the schistosome life cycle and is especially highly transcribed in eggs, miracidia, and adult female worms. RNA inference was employed to knockdown SjILP in adults in vitro, with suppression confirmed by significantly reduced protein production, declined adenosine diphosphate levels, and reduction in glucose consumption. Immunolocalization showed that SjILP is located to lateral gland cells of mature intra-ovular miracidia in the schistosome egg, and is distributed on the ciliated epithelium and internal cell masses of newly transformed miracidia. In schistosomula, SjILP is present on the tegument in two antero-lateral points, indicating highly polarized expression during cercarial transformation. Analysis of serum from S. japonicum-infected mice by ELISA using a recombinant form of SjILP as an antigen revealed IgG immunoreactivity to this molecule at 7 weeks post-infection indicating it is likely secreted from mature eggs into the host circulation. These findings provide further insights on ILP function in schistosomes and its essential roles in parasite survival and growth in different development stages

Lysosome-associated membrane glycoprotein (LAMP)-preliminary study on a hidden antigen target for vaccination against schistosomiasis

Our previously reported gene atlasing of schistosome tissues revealed transcripts that were highly enriched in the digestive tract of Schistosoma mansoni. From these, we selected two candidates, Sm-LAMP and Sm-NPC2 for testing as vaccine targets. The two molecules were selected on the basis of relatively high expression in the gastrodermis, their potentially important biological function, divergence from homologous molecules of the host and possible apical membrane expression in the gastrodermis. Bacterially expressed recombinant peptides corresponding to regions excluding transmembrane domains of the selected vaccine targets were used in blinded vaccine trials in CBA mice using alum-CpG as adjuvant. Vaccine trials using the recombinant insoluble Sm-LAMP protein showed 16-25% significant reduction in total worm burden. Faecal egg count reduction was 52% and 60% in two trials, respectively, with similar results for the solubly expressed protein. Liver egg burden was reduced significantly (20% and 38%) with an insoluble recombinant Sm-LAMP in two trials, but not with the soluble recombinant form. Parasite fecundity was not affected by either Sm-LAMP protein preparations in the trials. It is concluded that Sm-LAMP may provide limited protection towards S. mansoni infections but could be used in combination with other vaccine candidates, to provide more comprehensive protection

Adult schistosomes have an epithelial bacterial population distinct from the surrounding mammalian host blood

BACKGROUND: Schistosomiasis is a neglected tropical parasitic and chronic disease affecting hundreds of millions of people. Adult schistosomes reside in the blood stream of the definitive mammalian host. These helminth parasites possess two epithelial surfaces, the tegument and the gastrodermis, both of which interact with the host during immune evasion and in nutrient uptake. METHODS: Female ARC Swiss mice (4–6 weeks old) were infected percutaneously with Schistosoma japonicum cercariae freshly shed from Oncomelania hupensis quadrasi snails (Philippines strain). Fluorescent in situ hybridisation (FISH) was performed by using fresh adult S. japonicum perfused from those infected mice. Adult S. japonicum worms were processed to isolate the tegument from the carcass containing the gastrodermis; blood and bile were collected individually from infected and uninfected mice. Total DNA extracted from all those samples were used for microbiome profiling. RESULTS: FISH and microbiome profiling showed the presence of bacterial populations on two epithelial surfaces of adult worms, suggesting they were distinct not only from the host blood but also from each other. Whereas microbial diversity was reduced overall in the parasite epithelial tissues when compared with that of host blood, specific bacterial taxa, including Anoxybacillus and Escherichia, were elevated on the tegument. Minimal differences were evident in the microbiome of host blood during an active infection, compared with that of control uninfected blood. However, sampling of bile from infected animals identified some differences compared with controls, including elevated levels of Limnohabitans, Clostridium and Curvibacter. CONCLUSIONS: Using FISH and microbial profiling, we were able to demonstrate, for the first time, that bacteria are presented on the epithelial surfaces of adult schistosomes. These schistosome surface-associated bacteria, which are distinct from the host blood microenvironment, should be considered as a new and important component of the host-schistosome interaction. The importance of individual bacterial species in relation to schistosome parasitism needs further elucidation

Use of Kinase Inhibitors against Schistosomes to Improve and Broaden Praziquantel Efficacy

Praziquantel (PZQ) is the drug of choice for schistosomiasis. The potential drug resistance necessitates the search for adjunct or alternative therapies to PZQ. Previous functional genomics has shown that RNAi inhibition of Ca2+/calmodulin-dependent protein kinase II (CaMKII) gene in Schistosoma adult worms significantly improved the effectiveness of PZQ. Here we tested the in vitro efficacy of 15 selective and nonselective CaMK inhibitors against Schistosoma mansoni and showed that PZQ efficacy was improved against refractory juvenile parasites when combined with these CaMK inhibitors. By measuring CaMK activity and the mobility of adult S. mansoni, we identified two nonselective CaMK inhibitors, Staurosporine (STSP) and 1Naphthyl PP1 (1NAPP1), as promising candidates for further study. The impact of STSP and 1NAPP1 was investigated in mice infected with S. mansoni in the presence or absence of a sub-lethal dose of PZQ against 2- and 7- day-old schistosomula and adults. Treatment with STSP/PZQ induced a significant (47-68%) liver egg burden reduction compared with mice treated with PZQ alone. The findings indicate that the combination of STSP and PZQ dosages significantly improved anti-schistosomal activity compared to PZQ alone, demonstrating the potential of selective and nonselective CaMK/ kinase inhibitors as a combination therapy with PZQ in treating schistosomiasis

Gene atlasing of digestive and reproductive tissues in Schistosoma mansoni

Background: While considerable genomic and transcriptomic data are available for Schistosoma mansoni, many of its genes lack significant annotation. A transcriptomic study of individual tissues and organs of schistosomes could play an important role in functional annotation of the unknown genes, particularly by providing rapid localisation data and thus giving insight into the potential roles of these molecules in parasite development, reproduction and homeostasis, and in the complex host-parasite interaction