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