Digoxin reveals a functional connection between HIV-1 integration preference and T-cell activation

PLoS Pathog. 2017 Jul 20;13(7):e1006460. doi: 10.1371/journal.ppat.1006460. eCollection 2017 Jul.

Abstract

HIV-1 integrates more frequently into transcribed genes, however the biological significance of HIV-1 integration targeting has remained elusive. Using a selective high-throughput chemical screen, we discovered that the cardiac glycoside digoxin inhibits wild-type HIV-1 infection more potently than HIV-1 bearing a single point mutation (N74D) in the capsid protein. We confirmed that digoxin repressed viral gene expression by targeting the cellular Na+/K+ ATPase, but this did not explain its selectivity. Parallel RNAseq and integration mapping in infected cells demonstrated that digoxin inhibited expression of genes involved in T-cell activation and cell metabolism. Analysis of >400,000 unique integration sites showed that WT virus integrated more frequently than N74D mutant within or near genes susceptible to repression by digoxin and involved in T-cell activation and cell metabolism. Two main gene networks down-regulated by the drug were CD40L and CD38. Blocking CD40L by neutralizing antibodies selectively inhibited WT virus infection, phenocopying digoxin. Thus the selectivity of digoxin depends on a combination of integration targeting and repression of specific gene networks. The drug unmasked a functional connection between HIV-1 integration and T-cell activation. Our results suggest that HIV-1 evolved integration site selection to couple its early gene expression with the status of target CD4+ T-cells, which may affect latency and viral reactivation.

MeSH terms

  • Anti-HIV Agents / pharmacology*
  • CD4-Positive T-Lymphocytes / drug effects
  • CD4-Positive T-Lymphocytes / immunology*
  • Cells, Cultured
  • Digoxin / pharmacology*
  • HIV Infections / drug therapy
  • HIV Infections / immunology*
  • HIV Infections / virology*
  • HIV-1 / drug effects
  • HIV-1 / genetics
  • HIV-1 / physiology*
  • Humans
  • Lymphocyte Activation / drug effects
  • Virus Integration / drug effects*
  • Virus Latency / drug effects

Substances

  • Anti-HIV Agents
  • Digoxin