NFAT1 enhances HIV-1 gene expression in primary human CD4 T cells

Clin Immunol. 2000 Mar;94(3):179-91. doi: 10.1006/clim.1999.4831.

Abstract

Cyclosporin A (CsA) is a potent inhibitor of the NFAT family of transcription factors that enhance T cell activation. The observation that human immunodeficiency virus type 1 (HIV-1)-positive transplant recipients have a reduced HIV-1 viral burden during treatment with CsA suggested that NFAT may play a direct role in enhancing transcription of the HIV-1 viral genome. Two sets of NFAT binding sites were identified in the HIV-1 long terminal repeat (LTR) promoter by in vitro footprinting with full-length recombinant NFAT protein, and gel shift analysis of nuclear protein from polyclonally activated primary CD4 T cells revealed specific binding of NFAT1 to the NFkappaB binding sites of the HIV-1 LTR. Activation of primary CD4 T cells transiently transfected with a HIV-1 LTR luciferase reporter plasmid, lacking the NFAT binding sites in the upstream putative negative regulatory element but maintaining the NFkappaB/NFAT sites, demonstrated increased HIV-1 gene expression when cotransfected with a NFAT1 expression vector. Moreover, CsA, FK506, and a dominant-negative NFAT1 protein independently inhibited HIV-1 LTR promoter activity in CD4 T cells stimulated with phorbol ester and calcium ionophore. In primary human CD4 T cells, CsA also inhibited promoter activity directed by multimers of binding sites for NFAT, while having no effect on NFkappaB multimer-driven promoter activity. Increasing NFAT1 levels in CD4 T cells transiently transfected with a HIV-1 provirus also increased p24 protein expression. Thus, NFAT may be a target for prevention of HIV-1 LTR-directed gene expression in human CD4 T cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Binding Sites
  • CD4-Positive T-Lymphocytes / metabolism*
  • CD4-Positive T-Lymphocytes / virology
  • Cyclosporine / pharmacology
  • DNA-Binding Proteins / antagonists & inhibitors
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / pharmacology*
  • Gene Expression / drug effects
  • HIV Core Protein p24 / genetics
  • HIV Long Terminal Repeat / drug effects
  • HIV-1 / genetics*
  • Humans
  • NF-kappa B / metabolism
  • NFATC Transcription Factors
  • Nuclear Proteins*
  • Transcription Factors / antagonists & inhibitors
  • Transcription Factors / metabolism
  • Transcription Factors / pharmacology*

Substances

  • DNA-Binding Proteins
  • HIV Core Protein p24
  • NF-kappa B
  • NFATC Transcription Factors
  • NFATC2 protein, human
  • Nuclear Proteins
  • Transcription Factors
  • Cyclosporine