Epstein-Barr virus microRNAs regulate B cell receptor signal transduction and lytic reactivation

PLoS Pathog. 2019 Jan 7;15(1):e1007535. doi: 10.1371/journal.ppat.1007535. eCollection 2019 Jan.

Abstract

MicroRNAs (miRNAs) are post-transcriptional regulatory RNAs that can modulate cell signaling and play key roles in cell state transitions. Epstein-Barr virus (EBV) expresses >40 viral miRNAs that manipulate both viral and cellular gene expression patterns and contribute to reprogramming of the host environment during infection. Here, we identified a subset of EBV miRNAs that desensitize cells to B cell receptor (BCR) stimuli, and attenuate the downstream activation of NF-kappaB or AP1-dependent transcription. Bioinformatics and pathway analysis of Ago PAR-CLIP datasets identified multiple EBV miRNA targets related to BCR signal transduction, including GRB2, SOS1, MALT1, RAC1, and INPP5D, which we validated in reporter assays. BCR signaling is critical for B cell activation, proliferation, and differentiation, and for EBV, is linked to reactivation. In functional assays, we demonstrate that EBV miR-BHRF1-2-5p contributes to the growth of latently infected B cells through GRB2 regulation. We further determined that activities of EBV miR-BHRF1-2-5p, EBV miR-BART2-5p, and a cellular miRNA, miR-17-5p, directly regulate virus reactivation triggered by BCR engagement. Our findings provide mechanistic insight into some of the key miRNA interactions impacting the proliferation of latently infected B cells and importantly, governing the latent to lytic switch.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • B-Lymphocytes / virology
  • Cell Line
  • Epstein-Barr Virus Infections / virology
  • GRB2 Adaptor Protein / metabolism*
  • GRB2 Adaptor Protein / physiology
  • Gene Expression Regulation, Viral / genetics
  • HEK293 Cells
  • Herpesvirus 4, Human / genetics*
  • Herpesvirus 4, Human / immunology
  • Humans
  • MicroRNAs / genetics
  • NF-kappa B / metabolism
  • Receptors, Antigen, B-Cell / genetics
  • Receptors, Antigen, B-Cell / physiology*
  • Signal Transduction
  • Viral Proteins / metabolism
  • Virus Latency / genetics

Substances

  • GRB2 Adaptor Protein
  • GRB2 protein, human
  • MicroRNAs
  • NF-kappa B
  • Receptors, Antigen, B-Cell
  • Viral Proteins