Project description:The zoonotic mosquito-borne filarial nematode Dirofilaria repens causes subcutaneous and ocular infections in dogs, cats and humans. Microfilariae (mf) are taken up by mosquitoes from infected vertebrate hosts which develop in the mosquito to the infectious third stage larvae (L3). These are transmitted to new vertebrate hosts and develop over two further moults to adult worms. The aims of the project were 1) the de novo sequencing and annotation of the D. repens genome and 2) comparative transcriptome analyses of the developmental stages mf and L3 as we hypothesized remarkable differences in gene expression between the different developmental stages. Genomic DNA was obtained from adult male D. repens. RNA was extracted from microfilariae from naturally infected dogs and from L3 produced in Aedes aegypti mosquitoes fed on blood spiked with microfi-lariae. The 99.59 MB genome was around 17% larger than that of the related species D. immitis (dog heartworm) and contained 8.9% fewer predicted genes (10,357). Around 1.8% of identified proteins (206/11,262) could not be mapped to D. immitis. Out of these, 6 (2.9 %) presented an ortholog in all other considered filarial nematodes (e.g. Loa loa) and Caenorhabditis elegans. A sig-nificantly higher number of D. repens proteins as compared to D. immitis mapped to the filarial nem-atode L. loa, reflecting the similarity in biology of D. repens and L. loa. A total of 876 genes were differentially expressed, of which 591 could be annotated in UniProtKB/Swiss-Prot. In particular, 155 genes with a UniProtKB/Swiss-Prot annotation to C. elegans and filarial nematodes were upregulat-ed in the L3 and 57 in the mf stage, respectively. Fifteen GO BP (Gene Ontology Biological Pro-cesses) were significantly enriched for the L3 group and 12 for the mf. These data provide first in-sight into the differential gene expression profiles of this filarial nematode and can serve for future investigations of metabolic processes and stage-specific diagnostics.
Project description:We report the presence of circulating miRNAs released by the filarial nematode Dirofilaria immitis into the host (Canis familiaris) bloodstream.
