Toll-Interacting Protein Suppresses HIV-1 Long-Terminal-Repeat-Driven Gene Expression and Silences the Post-Integrational Transcription of Viral Proviral DNA

PLoS One. 2015 Apr 27;10(4):e0125563. doi: 10.1371/journal.pone.0125563. eCollection 2015.

Abstract

Toll-interacting protein (Tollip) is a host adaptor protein for negatively regulating Toll-like receptor 2-, 4-, and IL-1R (interleukin-1 receptor)-mediated signaling. We found that Tollip expression could be induced in MDDCs (monocyte-derived dendritic cells) by HIV-1 particles and recombinant gp120 glycoprotein. Hence, we investigated the role of Tollip in modulating HIV-1 infection. We found that Tollip expression suppressed NF-κB-dependent HIV-1 long terminal repeat (LTR)-driven transcription and thus inhibited HIV-1 infection. Our protein truncation experiments proved that the intact C-terminus of Tollip was required for inhibition of both NF-κB activity and HIV-1 LTR-driven gene expression. Intriguingly, Tollip silenced the post-integrational transcription of HIV-1 proviral DNA, indicating the potential role of Tollip in maintaining viral persistence. Our results reveal the novel role of host factor Tollip in modulating HIV-1 infection, and may suggest the hijacking of Tollip as the negative regulator of the TLR pathway and even the downstream signaling, by HIV-1 for maintaining persistent infection. Further elucidation of the mechanisms by which HIV-1 induces Tollip expression and identification of the role of Tollip in modulating HIV-1 latency will facilitate the understanding of host regulation in viral replication and benefit the exploration of novel strategies for combating HIV-1 infection.

MeSH terms

  • Cells, Cultured
  • DNA, Viral / genetics*
  • Dendritic Cells / cytology
  • Dendritic Cells / metabolism
  • HEK293 Cells
  • HIV Envelope Protein gp120 / genetics
  • HIV Envelope Protein gp120 / immunology
  • HIV Envelope Protein gp120 / metabolism
  • HIV Infections / genetics
  • HIV Infections / immunology
  • HIV Infections / virology*
  • HIV Long Terminal Repeat*
  • HIV-1 / genetics*
  • HIV-1 / immunology
  • HIV-1 / metabolism
  • HeLa Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins / chemistry
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Monocytes / cytology
  • Monocytes / immunology
  • Monocytes / virology
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • Transcription, Genetic
  • Virus Integration

Substances

  • DNA, Viral
  • HIV Envelope Protein gp120
  • Intracellular Signaling Peptides and Proteins
  • NF-kappa B
  • TOLLIP protein, human
  • gp120 protein, Human immunodeficiency virus 1

Grants and funding

The authors have no support or funding to report.