Project description:We report the presence of Onchocerca ochengi and O. volvulus derived small RNAs in bovine nodule fluids and human serum and plasma, respectively. Further comparisons with other related filarial nematodes like Litomosoides sigmodontis and Dirofilaria immitis reveal common and distictive signatures associated to the Onchocerca species.
Project description:We report the presence of Onchocerca ochengi and O. volvulus derived small RNAs in bovine nodule fluids and human serum and plasma, respectively. Further comparisons with other related filarial nematodes like Litomosoides sigmodontis and Dirofilaria immitis reveal common and distictive signatures associated to the Onchocerca species. Examination of small RNA content in bovine nodule fluids and human serum/plasma by Next Generation sequencing
Project description:In spite of 40 years of control efforts, onchocerciasis (river blindness) remains one of the most important neglected tropical diseases, with 17 million people affected. The aetiological agent, Onchocerca volvulus, is a filarial nematode with a complex lifecycle involving several distinct stages in the definitive host and blackfly vector. The challenges of obtaining sufficient material have prevented high-throughput studies and the development of novel strategies for disease control and diagnosis. Here, we utilise the closest relative of O. volvulus, the bovine parasite Onchocerca ochengi, to compare stage-specific proteomes and host-parasite interactions within the secretome. We identified a total of 4,260 unique O. ochengi proteins from adult males and females, infective larvae, intrauterine microfilariae, and fluid from intradermal nodules. In addition, 135 proteins were detected from the obligate Wolbachia symbiont. Observed protein families that were enriched in all whole body extracts relative to the complete search database included immunoglobulin-domain proteins, whereas redox and detoxification enzymes and proteins involved in intracellular transport displayed stage-specific overrepresentation. Unexpectedly, the larval stages exhibited enrichment for several mitochondrial-related protein families, including members of peptidase family M16 and proteins which mediate mitochondrial fission and fusion. Quantification of proteins across the lifecycle using the Hi 3 approach supported these qualitative analyses. In nodule fluid, we identified 94 O. ochengi secreted proteins, including two homologs of transforming growth factor and a second member of a novel 6 ShK toxin domain family, which was originally identified from a model filarial nematode (Litomosoides sigmodontis). Strikingly, the 498 bovine proteins identified in nodule fluid were strongly dominated by antimicrobial proteins, especially cathelicidins. This first high-throughput analysis of an Onchocerca spp. proteome highlights its profound complexity and emphasises the extremely close relationship between O. ochengi and O. volvulus. The insights provided here provide new candidates for vaccine development, drug targeting and diagnostic biomarkers.
Project description:Filarial nematodes possess glutathione transferases (GSTs), ubiquitous enzymes with potential to detoxify xenobiotic and endogenous substrates, and modulate the host immune system, which may aid worm infection establishment, maintenance and survival in the host. Here we have identified and characterised a sigma class glycosylated GST (OoGST1), from the cattle-infective filarial nematode Onchocerca ochengi, which is homologous (99% amino acid identity) with an immunodominant GST and potential vaccine candidate from the human parasite, O. volvulus, (OvGST1b). O. ochengi native GSTs were purified using a two-step affinity chromatography approach, resolved by 2D and 1D SDS-PAGE and subjected to enzymic deglycosylation revealing the existence of at least four glycoforms. A combination of lectin-blotting and mass spectrometry (MS) analyses of the released N-glycans indicated that OoGST1 contained mainly oligomannose Man5GlcNAc2 structure, but also hybrid- and larger oligommanose-type glycans in a lower proportion. Furthermore, purified OoGST1 showed prostaglandin synthase activity as confirmed by Liquid Chromatography (LC)/MS following a coupled-enzyme assay. This is only the second reported and characterised glycosylated GST and our study highlights its potential role in host-parasite interactions and use in the study of human onchocerciasis.
Project description:Genomic assembly of nematode Onchocerca ochengi, as part of the 50 Helminth Genomes Initiative sequencing of the parasitic worms that have the greatest impact on human, agricultural and veterinary disease and cause significant global health issues particularly in the developing world, or those used as model organisms.