Chromatin maturation of the HIV-1 provirus in primary resting CD4+ T cells

PLoS Pathog. 2020 Jan 30;16(1):e1008264. doi: 10.1371/journal.ppat.1008264. eCollection 2020 Jan.

Abstract

Human immunodeficiency virus type 1 (HIV-1) infection is a chronic condition, where viral DNA integrates into the genome. Latently infected cells form a persistent, heterogeneous reservoir that at any time can reactivate the integrated HIV-1. Here we confirmed that latently infected cells from HIV-1 positive study participants exhibited active HIV-1 transcription but without production of mature spliced mRNAs. To elucidate the mechanisms behind this we employed primary HIV-1 latency models to study latency establishment and maintenance. We characterized proviral transcription and chromatin development in cultures of resting primary CD4+ T-cells for four months after ex vivo HIV-1 infection. As heterochromatin (marked with H3K9me3 or H3K27me3) gradually stabilized, the provirus became less accessible with reduced activation potential. In a subset of infected cells, active marks (e.g. H3K27ac) and elongating RNAPII remained detectable at the latent provirus, despite prolonged proviral silencing. In many aspects, latent HIV-1 resembled an active enhancer in a subset of resting cells. The enhancer chromatin actively promoted latency and the enhancer-specific CBP/P300-inhibitor GNE049 was identified as a new latency reversal agent. The division of the latent reservoir according to distinct chromatin compositions with different reactivation potential enforces the notion that even though a relatively large set of cells contains the HIV-1 provirus, only a discrete subset is readily able to reactivate the provirus and spread the infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD4-Positive T-Lymphocytes / immunology*
  • CD4-Positive T-Lymphocytes / virology
  • Chromatin / virology*
  • HIV Infections / immunology
  • HIV Infections / virology*
  • HIV-1 / genetics
  • HIV-1 / physiology*
  • Humans
  • Proviruses / genetics
  • Proviruses / physiology*
  • Virus Activation
  • Virus Assembly
  • Virus Latency

Substances

  • Chromatin

Grants and funding

Vetenskapsrådet-M (2015-02312, 2019-00991, https://vr.se), Cancerfonden (2016/576, 19 0412 Pj, https://www.cancerfonden.se), Åke Wibergs Stiftelse (M14-0205, M15-0044, M16- 0022, http://ake-wiberg.se), Clas Groschinskys Minnesfond (M1662, M1790, http://www.groschinsky.org), and Läkare mot AIDS Forskningsfond (FOb2017-0001 http://www.aidsfond.se), awarded to J.P.S.; and Vetenskapsrådet-M (2016-01675, https://vr.se) and Karolinska Institutet (KID-grant 2-1930/2016, http://ki.se) awarded to A.S.; and from CIMED and Region Stockholm (Project 20190092, http://cimed.ki.se), awarded to A.S. and J.P.S. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.