Poly(ADP-ribose) polymerase 1 is necessary for coactivating hypoxia-inducible factor-1-dependent gene expression by Epstein-Barr virus latent membrane protein 1

PLoS Pathog. 2018 Nov 5;14(11):e1007394. doi: 10.1371/journal.ppat.1007394. eCollection 2018 Nov.

Abstract

Latent membrane protein 1 (LMP1) is the major transforming protein of Epstein-Barr virus (EBV) and is critical for EBV-induced B-cell transformation in vitro. Poly(ADP-ribose) polymerase 1 (PARP1) regulates accessibility of chromatin, alters functions of transcriptional activators and repressors, and has been directly implicated in transcriptional activation. Previously we showed that LMP1 activates PARP1 and increases Poly(ADP-ribos)ylation (PARylation) through PARP1. Therefore, to identify targets of LMP1 that are regulated through PARP1, LMP1 was ectopically expressed in an EBV-negative Burkitt's lymphoma cell line. These LMP1-expressing cells were then treated with the PARP inhibitor olaparib and prepared for RNA sequencing. The LMP1/PARP targets identified through this RNA-seq experiment are largely involved in metabolism and signaling. Interestingly, Ingenuity Pathway Analysis of RNA-seq data suggests that hypoxia-inducible factor 1-alpha (HIF-1α) is an LMP1 target mediated through PARP1. PARP1 is acting as a coactivator of HIF-1α-dependent gene expression in B cells, and this co-activation is enhanced by LMP1-mediated activation of PARP1. HIF-1α forms a PARylated complex with PARP1 and both HIF-1α and PARP1 are present at promoter regions of HIF-1α downstream targets, leading to accumulation of positive histone marks at these regions. Complex formation, PARylation and binding of PARP1 and HIF-1α at promoter regions of HIF-1α downstream targets can all be attenuated by PARP1 inhibition, subsequently leading to a buildup of repressive histone marks and loss of positive histone marks. In addition, LMP1 switches cells to a glycolytic 'Warburg' metabolism, preferentially using aerobic glycolysis over mitochondrial respiration. Finally, LMP1+ cells are more sensitive to PARP1 inhibition and, therefore, targeting PARP1 activity may be an effective treatment for LMP1+ EBV-associated malignancies.

Publication types

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

MeSH terms

  • B-Lymphocytes / virology
  • Cell Line, Tumor
  • Gene Expression Regulation, Viral
  • Herpesvirus 4, Human / genetics*
  • Herpesvirus 4, Human / metabolism*
  • Host-Pathogen Interactions
  • Humans
  • Hypoxia-Inducible Factor 1 / genetics
  • Hypoxia-Inducible Factor 1 / metabolism*
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Phthalazines / pharmacology
  • Piperazines / pharmacology
  • Poly (ADP-Ribose) Polymerase-1 / antagonists & inhibitors
  • Poly (ADP-Ribose) Polymerase-1 / metabolism*
  • Signal Transduction
  • Transcriptional Activation
  • Viral Matrix Proteins / genetics
  • Viral Matrix Proteins / metabolism*

Substances

  • EBV-associated membrane antigen, Epstein-Barr virus
  • Hypoxia-Inducible Factor 1
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Phthalazines
  • Piperazines
  • Viral Matrix Proteins
  • PARP1 protein, human
  • Poly (ADP-Ribose) Polymerase-1
  • olaparib

Grant support

Research reported in this publication was supported by the National Institute Of Allergy And Infectious Diseases of the National Institutes of Health under Award Number R01AI130209. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.