The small non-coding RNA response to virus infection in the Leishmania vector Lutzomyia longipalpis

PLoS Negl Trop Dis. 2018 Jun 4;12(6):e0006569. doi: 10.1371/journal.pntd.0006569. eCollection 2018 Jun.

Abstract

Sandflies are well known vectors for Leishmania but also transmit a number of arthropod-borne viruses (arboviruses). Few studies have addressed the interaction between sandflies and arboviruses. RNA interference (RNAi) mechanisms utilize small non-coding RNAs to regulate different aspects of host-pathogen interactions. The small interfering RNA (siRNA) pathway is a broad antiviral mechanism in insects. In addition, at least in mosquitoes, another RNAi mechanism mediated by PIWI interacting RNAs (piRNAs) is activated by viral infection. Finally, endogenous microRNAs (miRNA) may also regulate host immune responses. Here, we analyzed the small non-coding RNA response to Vesicular stomatitis virus (VSV) infection in the sandfly Lutzoymia longipalpis. We detected abundant production of virus-derived siRNAs after VSV infection in adult sandflies. However, there was no production of virus-derived piRNAs and only mild changes in the expression of vector miRNAs in response to infection. We also observed abundant production of virus-derived siRNAs against two other viruses in Lutzomyia Lulo cells. Together, our results suggest that the siRNA but not the piRNA pathway mediates an antiviral response in sandflies. In agreement with this hypothesis, pre-treatment of cells with dsRNA against VSV was able to inhibit viral replication while knock-down of the central siRNA component, Argonaute-2, led to increased virus levels. Our work begins to elucidate the role of RNAi mechanisms in the interaction between L. longipalpis and viruses and should also open the way for studies with other sandfly-borne pathogens.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Host-Pathogen Interactions*
  • Insect Vectors / parasitology
  • Insect Vectors / virology*
  • Leishmania / physiology
  • MicroRNAs / genetics
  • Psychodidae / genetics*
  • Psychodidae / immunology
  • Psychodidae / physiology
  • Psychodidae / virology*
  • RNA Interference
  • RNA, Small Interfering / genetics
  • RNA, Untranslated*
  • RNA, Viral / genetics
  • Vesicular stomatitis Indiana virus / genetics
  • Vesicular stomatitis Indiana virus / physiology*
  • Virus Replication

Substances

  • MicroRNAs
  • RNA, Small Interfering
  • RNA, Untranslated
  • RNA, Viral

Grants and funding

This work was supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (http://www.cnpq.br), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (http://www.capes.gov.br/) and Fundação de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG) (http://www.fapemig.br) to JTM and EGK; and Agence Nationale de la Recherche (http://www.agence-nationale-recherche.fr/)(ANR-11-ASV3-002), Investissement d’AvenirPrograms (ANR-10-LABX-36; ANR-11-EQPX-0022) to JLI. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.