Project description:We sequenced total RNA from Dirofilaria immitis in order to generate the first tissue-specific gene expression profile of a filarial nematode and its Wolbachia endosymbiont.
Project description:We sequenced total RNA from Dirofilaria immitis in order to generate the first tissue-specific gene expression profile of a filarial nematode and its Wolbachia endosymbiont. Examination of transcript levels in 7 different Dirofilaria immitis tissues, in duplicate, using Illumina GAIIx.
Project description:Lymphatic filarial nematodes maintain a mutualistic association with the intracellular bacterium Wolbachia. Wolbachia populations expand following infection of the mammalian host, to support larval growth and development. Utilizing transcriptomic data from Brugia malayi over the first two weeks post-infection, we present an analysis of the biochemical pathways that are involved in Wolbachia population growth and regulation in support of larval development. In Wolbachia, we observe coordinated regulation of carbon metabolism with an alternating pattern of glycolysis and TCA cycle pathways reminiscent of the ‘Warburg effect’. Wolbachia's purine, pyrimidine and haem biosynthesis and Type IV secretion pathways are also upregulated and correlate with the upregulation of the nematode’s DNA replication pathway. In the nematode we observe up-regulation of the autophagy pathway, a key regulator of Wolbachia populations. These findings support a key role for nucleotide and haem provisioning from Wolbachia in support of the larval growth and development of its nematode host.
Project description:Brugia malayi is a parasitic nematode that causes lymphatic filariasis in humans. A total of 178 novel microRNA were identified from short read transcriptional data, which when combined with known Brugia microRNAs yielded a total of 284 microRNA. Of these, 123 microRNA sequences (43%) are differentially expressed over the mammalian life stages of B. malayi that we examined. Putative targets of these microRNA were identified from inversely expressed target clusters that contain valid seed sequences for the corresponding microRNAs. The largest identified cluster is downregulated in adult females and enriched in zinc finger domains, helicase domains, and DNA binding domains suggesting this microRNA cluster may have regulatory control over a large proportion of adult female specific mRNA genes. MicroRNA-like molecules are identified as produced by the Wolbachia endosymbiont, providing evidence for direct nucleic acid-based interdomain communication between filarial nematodes and their bacterial obligate endosymbiont.
Project description:The filarial nematodes Brugia malayi, Wuchereria bancrofti and Onchocerca volvulus cause elephantiasis, dermatitis and blindness, resulting in severe morbidity in developing countries. 1.3 billion people are at risk of infection. Targeting the essential Wolbachia endobacteria of filarial nematodes with doxycycline has proven to be an effective therapy, resulting in a block in embryogenesis and worm development, and macrofilaricidal effects. However, doxycycline is contraindicated for a large portion of the at-risk population. To identify new targets for anti-wolbachial therapy, understanding the molecular basis of the Wolbachia-filaria symbiosis is required. We performed cross-species hybridization by using the Brugia malayi microarray to identify differentially expressed genes in the rodent filaria Litomosoides sigmodontis after depletion of Wolbachia which therefore might have a role in symbiosis.
Project description:Filarial nematodes (superfamily Filarioidea) are responsible for an annual global health burden of approximately 6.3 million disability-adjusted life-years, which represents the greatest single component of morbidity attributable to helminths affecting humans. No vaccine exists for the major filarial diseases, lymphatic filariasis and onchocerciasis; in part because research on protective immunity against filariae has been constrained because the human-parasitic species cannot complete their lifecycles in laboratory mice. However, the rodent filaria Litomosoides sigmodontis has become a popular experimental model, as BALB/c mice are fully permissive for its development and reproduction. Here, we provide a comprehensive analysis of excretory-secretory products from L. sigmodontis across five lifecycle stages. Applying intensity-based quantification, we determined the abundance of 302 unique excretory-secretory proteins, of which 64.6% were present in quantifiable amounts only from gravid adult female nematodes. This lifecycle stage, together with immature first-stage larvae (microfilariae), released four proteins that have not previously been evaluated as vaccine candidates: a predicted 28.5 kDa filaria-specific protein, a zonadhesin and SCO-spondin-like protein, a vitellogenin, and a protein containing six metridin-like ShK toxin domains. Female nematodes also released two proteins derived from the obligate Wolbachia symbiont. Notably, excretory-secretory products from all parasite stages contained several uncharacterised members of the transthyretin-like protein family. Furthermore, biotin labelling revealed that redox proteins and enzymes involved in purinergic signalling were enriched on the adult nematode cuticle. Comparison of the L. sigmodontis adult secretome with that of the human–infective filarial nematode Brugia malayi (reported previously in three independent published studies) identified differences that suggest a considerable underlying diversity of potential immunomodulators. The molecules identified in L. sigmodontis excretory-secretory products show promise not only for vaccination against filarial infections, but for the amelioration of allergy and autoimmune diseases.
Project description:The filarial nematodes Brugia malayi, Wuchereria bancrofti and Onchocerca volvulus cause elephantiasis, dermatitis and blindness, resulting in severe morbidity in developing countries. 1.3 billion people are at risk of infection. Targeting the essential Wolbachia endobacteria of filarial nematodes with doxycycline has proven to be an effective therapy, resulting in a block in embryogenesis and worm development, and macrofilaricidal effects. However, doxycycline is contraindicated for a large portion of the at-risk population. To identify new targets for anti-wolbachial therapy, understanding the molecular basis of the Wolbachia-filaria symbiosis is required. We performed cross-species hybridization by using the Brugia malayi microarray to identify differentially expressed genes in the rodent filaria Litomosoides sigmodontis after depletion of Wolbachia which therefore might have a role in symbiosis. Female adult Litomosoides sigmodontis from patent infections were treated with tetracycline to deplete endosymbiotic Wolbachia bacteria. RNA from tetracycline-treated Litomosoides sigmodontis was compared to untreated age-matched control worms. This experiment was performed for three different timepoints: day 6, 15 and 36 of tetracycline treatment. One biological replicate was performed each with two technical replicates (dye-flip replicates).
Project description:Intracellular bacteria have been observed in various species of filarial nematodes (family Onchocercidae). The intracellular bacterium of the canine filaria Dirofilaria immitis has been shown to be closely related to Wolbachia, a rickettsia-like micro-organism that is widespread among arthropods. However, the relationships between endosymbionts of different filariae, and between these and the arthropod wolbachiae, appear not to have been studied. To address these issues we have examined ten species of filarial nematodes for the presence of Wolbachia. For nine species, all samples examined were PCR positive using primers specific for the ftsZ gene of Wolbachia. For one species, the examined samples were PCR negative. Sequences of the amplified ftsZ gene fragments of filarial wolbachiae fall into two clusters (C and D), which are distinct from the A and B clusters recognized for arthropod wolbachiae. These four lineages (A-D) are related in a star-like phylogeny, with higher nucleotide divergence observed between C and D wolbachiae than that observed between A and B wolbachiae. In addition, within each of the two lineages of filarial wolbachiae, the phylogeny of the symbionts is consistent with the host phylogeny. Thus, there is no evidence for recent Wolbachia transmission between arthropods and nematodes. Endosymbiont 16S ribosomal DNA sequences from a subset of filarial species support these findings.
Project description:The helminth Acanthocheilonema viteae serves as model organism for research on parasitic filarial nematodes. Total RNA secreted or excreted by 1500 adult female and male A. viteae over 3 weeks was isolated from culture media previously processed by differential ultracentrifugation, and subjected to miRNA sequencing.
Project description:Wolbachia, an endosymbiotic bacterium, is being investigated as a vector control agent in several insect species. Along with the well known classical reproductive parasitism Wolbachia employs against its host to spread within the population, it is emerging that the bacteria can protect the host against pathogens and reduced pathogen transmission. Anopheles mosquitoes, which transmit malaria, have never been found to harbour Wolbachia in nature, and despite numerous transinfection attempts, no stable line has been developed. However recently, two strains of Wolbachia, wAlbB from Aedes albopictus, and wRi from Drosophila simulans were cultured in Anopheles gambiae Sua5B cells. These cell lines provides an amenable system to study Wolbachia-Anopheles interaction in the absence of a stable transinfected line. It has been proposed that the compromised vector competence of Wolbachia infected insects is due to an up regulation of the basal immune state. We therefore completed a genome wide expression profile of Wolbachia infected Anopheles, assessing both wAlbB and wRi infected cells in parallel against uninfected Sua5B cells.