The transcriptional landscape of Venezuelan equine encephalitis virus (TC-83) infection

PLoS Negl Trop Dis. 2021 Mar 31;15(3):e0009306. doi: 10.1371/journal.pntd.0009306. eCollection 2021 Mar.

Abstract

Venezuelan Equine Encephalitis Virus (VEEV) is a major biothreat agent that naturally causes outbreaks in humans and horses particularly in tropical areas of the western hemisphere, for which no antiviral therapy is currently available. The host response to VEEV and the cellular factors this alphavirus hijacks to support its effective replication or evade cellular immune responses are largely uncharacterized. We have previously demonstrated tremendous cell-to-cell heterogeneity in viral RNA (vRNA) and cellular transcript levels during flaviviral infection using a novel virus-inclusive single-cell RNA-Seq approach. Here, we used this unbiased, genome-wide approach to simultaneously profile the host transcriptome and vRNA in thousands of single cells during infection of human astrocytes with the live-attenuated vaccine strain of VEEV (TC-83). Host transcription was profoundly suppressed, yet "superproducer cells" with extremely high vRNA abundance emerged during the first viral life cycle and demonstrated an altered transcriptome relative to both uninfected cells and cells with high vRNA abundance harvested at later time points. Additionally, cells with increased structural-to-nonstructural transcript ratio exhibited upregulation of intracellular membrane trafficking genes at later time points. Loss- and gain-of-function experiments confirmed pro- and antiviral activities in both vaccine and virulent VEEV infections among the products of transcripts that positively or negatively correlated with vRNA abundance, respectively. Lastly, comparison with single cell transcriptomic data from other viruses highlighted common and unique pathways perturbed by infection across evolutionary scales. This study provides a high-resolution characterization of the VEEV (TC-83)-host interplay, identifies candidate targets for antivirals, and establishes a comparative single-cell approach to study the evolution of virus-host interactions.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antibodies, Viral / immunology
  • Astrocytes / virology
  • Biological Transport / genetics*
  • Cell Line
  • Chlorocebus aethiops
  • Cricetinae
  • Encephalitis Virus, Venezuelan Equine / genetics*
  • Encephalitis Virus, Venezuelan Equine / immunology
  • Encephalomyelitis, Venezuelan Equine / pathology*
  • Gene Expression Regulation, Viral / genetics
  • Horses
  • Host-Pathogen Interactions / genetics*
  • Humans
  • RNA, Viral / genetics
  • Single-Cell Analysis
  • Transcription, Genetic / genetics*
  • Vaccines, Attenuated / immunology
  • Vero Cells
  • Virus Internalization*
  • Virus Replication / physiology

Substances

  • Antibodies, Viral
  • RNA, Viral
  • Vaccines, Attenuated

Grants and funding

This work was supported by HDTRA11810039 from the Defense Threat Reduction Agency (DTRA)/Fundamental Research to Counter Weapons of Mass Destruction to SE and AN, by the Chan Zuckerberg Biohub to SQ, and by a Stanford Bio-X Interdisciplinary Initiative Program Award to SE. ZY was supported by the Maternal and Child Health Research Institute, Lucile Packard Foundation for Children’s Health). NP was supported by the University of Washington School of Medicine Guy Tribble and Susan Barnes Graduate Discovery Fellowship. We thank investigators who have provided plasmids (see Methods). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.