Extracellular non-coding RNA signatures of the metacestode stage of Echinococcus multilocularis

ANCAROLA E; LICHTENSTEIN, G.; HERBIS, J.; HOLROYD,N.; MARICONTI, M.; BRUNETTI, E.; BERRIMAN, M.; ALBRECHT, K.; MARCILLA, A.; ROSENZVIT, M.; KAMENETZKY, L.; BREHM, K.; CUCHER, M.

PLOS NEGLECTED TROPICAL DISEASES

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2020

1935-2735

Extracellular RNAs (ex-RNAs) are secreted by cells through different means that mayinvolve association with proteins, lipoproteins or extracellular vesicles (EV). In thecontext of parasitism, ex-RNAs represent new and exciting communicationintermediaries with promising potential as novel biomarkers. In the last years, it wasshown that helminth parasites secrete ex-RNAs, however, most work mainly focusedon RNA secretion mediated by EV. Ex-RNA study is of special interest in thosehelminth infections that still lack biomarkers for early and/or follow-up diagnosis, suchas echinococcosis, a neglected zoonotic disease caused by cestodes of the genusEchinococcus . In this work, we have characterised the ex-RNA profile secreted by invitro grown metacestodes of Echinococcus multilocularis , the casuative agent of alveolar echinococcosis.Methodology/Principal findingsWe have used high throughput RNA-sequencing together with RT-qPCR tocharacterise the ex-RNA profile secreted towards the extra- and intra-parasite milieusin EV-enriched and EV-depleted fractions. We show that a polarized secretion of smallRNAs takes place, with microRNAs mainly secreted to the extra-parasite milieu andrRNA- and tRNA-derived sequences mostly secreted to the intra-parasite milieu. Inaddition, we show by nanoparticle tracking analyses that viable metacestodes secreteEV mainly into the metacestode inner vesicular fluid (MVF); however, the number ofnanoparticles in culture medium and MVF increases > 10-fold when metacestodesshow signs of tegument impairment. Interestingly, we confirm the presence of hostmiRNAs in the intra-parasite milieu, implying their internalization and transport throughthe tegument towards the MVF. Finally, our assessment of the detection ofEchinococcus miRNAs in patient samples by RT-qPCR yielded negative resultssuggesting the tested miRNAs may not be good biomarkers for this disease.Conclusions/SignificanceA comprehensive study of the secretion mechanisms throughout the life cycle of theseparasites will help to understand parasite interaction with the host and also, improvecurrent diagnostic tools.