Project description:Urogenital schistosomiasis (caused by Schistosoma haematobium) remains a major public health concern worldwide. In response to parasite egg deposition, the host bladder undergoes gross and molecular morphological changes relevant for disease manifestation. However, limited mechanistic studies to date imply that the molecular mechanisms underlying pathology have not been well-defined. We leveraged a mouse model of urogenital schistosomiasis to perform for the first time, proteome profiling of the early molecular events that occur in the bladder after exposure to S. haematobium eggs, and to elucidate the protein pathways involved in urogenital schistosomiasis-induced pathology. Purified S. haematobium eggs or control vehicle were microinjected into the bladder walls of mice. Mice were sacrificed seven days post-injection and bladder proteins isolated and processed for proteome profiling using mass spectrometry.
Project description:Despite the clear role of adult secreted and tegumental proteins as well as egg proteins in host-parasite interactions, there has not been any in-depth proteomic analysis of these or other Schistosoma haematobium proteomes. In the current project we have carried out the first comprehensive proteomic analysis of S. haematobium. The characterisation of the molecules playing a key role at the interphase between the host and the parasite is crucial for (i) a better understanding of the parasite’s biology and, (ii) for the development of new control and diagnostic approaches to tackle parasitic infections.
Project description:Schistosome worms infect over 200 million people worldwide. They live in the host’s bloodstream and alter host immunity. Epidemiological data suggest that males and females have different responses to schistosome infection, but the effect of sex on systemic response is undetermined. Our objective was to characterize differences in peripheral blood transcriptional profiles in people with or without active Schistosoma haematobium infection and to determine whether this signature differs between males and females. mRNA was isolated using poly(A) selection and sequenced on an Illumina Hi-Seq4000 platform. Transcripts were aligned to the human hg19 reference genome and counted with the HTSeq package. Genes were compared for differential expression using DESeq2. Ingenuity Pathway Analysis (IPA) was used to identify gene networks altered in the presence of S. haematobium. We enrolled 33 participants from villages in rural Tanzania where S. haematobium is endemic. After correction for multiple comparisons, we observed 383 differentially expressed genes between those with or without S. haematobium infection when sex was included as a covariate. Heat-mapping of the genes with 1.5-fold differences in gene expression revealed clustering by S. haematobium infection status. The top networks included development, cell death and survival, cell signaling, and immunologic disease pathways. We observed a distinct whole blood transcriptional profile, as well as differences in men and women, with S. haematobium infection. Additional studies are needed to determine the clinical effects of these divergent responses. Attention to sex-based differences should be included in studies of schistosome infection.
Project description:Schistosomiasis increases the risk of HIV acquisition in women, by mechanisms that are incompletely defined. Our objective was to determine how the cervical environment is impacted by Schistosoma haematobium or S. mansoni infection using mucosal gene expression and cervicovaginal lavage cytokine levels. We recruited women with/without S. haematobium and with/without S. mansoni infections from separate villages in rural Tanzania, as determined by urine and stool microscopy and serum circulating anodic antigen. RNA was extracted from cervical cytobrush samples for transcriptome analysis. Cytokine levels were measured by magnetic bead immunoassay. In the S. haematobium village, 110 genes were differentially expressed in the cervical mucosa of women with (n=18) versus without (n=39) S. haematobium. Among the 27 cytokines analyzed in cervicovaginal lavage fluids, interleukin 15 (IL-15) was lower in women with S. haematobium (62.8 versus 102.9 pg/mL, adjusted p=0.0013). Differences were not observed in the S. mansoni setting between women with (n=11) or without (n=29) S. mansoni. We demonstrate altered cervical mucosal gene expression and lower IL-15 levels in women with S. haematobium but not S. mansoni, which may impact HIV acquisition and cancer risks. Studies to determine effects of anti-schistosome treatment on these mucosal alterations are needed.
Project description:Oxamniquine resistance evolved in the human blood fluke (Schistosoma mansoni) in Brazil in the 1970s. We crossed parental parasites differing ~500-fold in drug response, determined drug sensitivity and marker segregation in clonally-derived F2s, and identified a single QTL (LOD=31) on chromosome 6. A sulfotransferase was identified as the causative gene using RNAi knockdown and biochemical complementation assays and we subsequently demonstrated independent origins of loss-of-function mutations in field-derived and laboratory-selected resistant parasites. These results demonstrate the utility of linkage mapping in a human helminth parasite, while crystallographic analyses of protein-drug interactions illuminate the mode of drug action and provide a framework for rational design of oxamniquine derivatives that kill both S. mansoni and S. haematobium, the two species responsible for >99% of schistosomiasis cases worldwide. mRNA profiles from adult worms resistant (HR, 3 replicates) and susceptible (LE, 2 replicates) to the oxamniquine drug were compared to identify differential expression in genes related to drug resistance