Viral microRNAs Target a Gene Network, Inhibit STAT Activation, and Suppress Interferon Responses

Sci Rep. 2017 Jan 19:7:40813. doi: 10.1038/srep40813.

Abstract

Kaposi's sarcoma-associated herpesvirus (KSHV) encodes 12 pre-microRNAs during latency that are processed to yield ~25 mature microRNAs (miRNAs). We were interested in identifying cellular networks that were targeted by KSHV-miRNAs and employed network building strategies using validated KSHV miRNA targets. Here, we report the identification of a gene network centering on the transcription factor- signal transducer and activator of transcription 3 (STAT3) that is targeted by KSHV miRNAs. KSHV miRNAs suppressed STAT3 and STAT5 activation and inhibited STAT3-dependent reporter activation upon IL6-treatment. KSHV miRNAs also repressed the induction of antiviral interferon-stimulated genes upon IFNα- treatment. Finally, we observed increased lytic reactivation of KSHV from latently infected cells upon STAT3 repression with siRNAs or a small molecule inhibitor. Our data suggest that treatment of infected cells with a STAT3 inhibitor and a viral replication inhibitor, ganciclovir, represents a possible strategy to eliminate latently infected cells without increasing virion production. Together, we show that KSHV miRNAs suppress a network of targets associated with STAT3, deregulate cytokine-mediated gene activation, suppress an interferon response, and influence the transition into the lytic phase of viral replication.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • 3' Untranslated Regions
  • Antagomirs
  • Base Sequence
  • Gene Regulatory Networks
  • Genetic Vectors
  • Herpesvirus 8, Human / genetics
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • Inhibitor of Apoptosis Proteins / genetics
  • Inhibitor of Apoptosis Proteins / metabolism
  • Interferons / metabolism*
  • Interleukin-6 / pharmacology
  • MicroRNAs / antagonists & inhibitors
  • MicroRNAs / genetics
  • MicroRNAs / metabolism
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Receptors, Erythropoietin / genetics
  • Receptors, Erythropoietin / metabolism
  • STAT3 Transcription Factor / antagonists & inhibitors
  • STAT3 Transcription Factor / genetics
  • STAT3 Transcription Factor / metabolism*
  • Sequence Alignment
  • Signal Transduction / drug effects
  • Survivin

Substances

  • 3' Untranslated Regions
  • Antagomirs
  • BIRC5 protein, human
  • Inhibitor of Apoptosis Proteins
  • Interleukin-6
  • MicroRNAs
  • RNA, Small Interfering
  • Receptors, Erythropoietin
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Survivin
  • Interferons