Viral E protein neutralizes BET protein-mediated post-entry antagonism of SARS-CoV-2

Cell Rep. 2022 Jul 19;40(3):111088. doi: 10.1016/j.celrep.2022.111088. Epub 2022 Jun 27.

Abstract

Inhibitors of bromodomain and extraterminal domain (BET) proteins are possible anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prophylactics as they downregulate angiotensin-converting enzyme 2 (ACE2). Here we show that BET proteins should not be inactivated therapeutically because they are critical antiviral factors at the post-entry level. Depletion of BRD3 or BRD4 in cells overexpressing ACE2 exacerbates SARS-CoV-2 infection; the same is observed when cells with endogenous ACE2 expression are treated with BET inhibitors during infection and not before. Viral replication and mortality are also enhanced in BET inhibitor-treated mice overexpressing ACE2. BET inactivation suppresses interferon production induced by SARS-CoV-2, a process phenocopied by the envelope (E) protein previously identified as a possible "histone mimetic." E protein, in an acetylated form, directly binds the second bromodomain of BRD4. Our data support a model where SARS-CoV-2 E protein evolved to antagonize interferon responses via BET protein inhibition; this neutralization should not be further enhanced with BET inhibitor treatment.

Keywords: BET inhibitors; BET proteins; BRD2; BRD3; BRD4; COVID-19; CP: Microbiology; SARS-CoV-2; antiviral response; histone mimetic; viral replication.

Publication types

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

MeSH terms

  • Angiotensin-Converting Enzyme 2
  • Animals
  • Antiviral Agents / pharmacology
  • COVID-19*
  • Interferons
  • Mice
  • Nuclear Proteins
  • SARS-CoV-2*
  • Transcription Factors
  • Viral Proteins

Substances

  • Antiviral Agents
  • Nuclear Proteins
  • Transcription Factors
  • Viral Proteins
  • Interferons
  • Angiotensin-Converting Enzyme 2