A transcriptionally permissive epigenetic landscape at the vasoactive intestinal peptide receptor-1 promoter suggests a euchromatin nuclear position in murine CD4 T cells

Regul Pept. 2009 Nov 27;158(1-3):68-76. doi: 10.1016/j.regpep.2009.08.010. Epub 2009 Sep 1.

Abstract

T cells express receptors for neuropeptides that mediate immunological activities. Vasoactive intestinal peptide receptor-1 (VPAC1), the prototypical group II G protein coupled receptor, binds two neuropeptides with high-affinity, called vasoactive intestinal peptide and pituitary adenylate cyclase activating polypeptide. During T cell signaling, VPAC1 mRNA expression levels are significantly downregulated through a Src kinase dependent mechanism, thus altering the sensitivity for these neuropeptides during an immune reaction. Presently, it is unknown whether the mechanism that regulates VPAC1 during T cell signaling involves epigenetic changes. Therefore, we hypothesized that the epigenetic landscape consisting of diacetylation at H3K9/14 and trimethylation at H3K4, two transcriptionally permissive histone modifications, would parallel VPAC1 expression showing high enrichment in untreated T cells, but lower enrichment in alpha-CD3 treated T cells. To this end, quantitative chromatin immunoprecipitation (ChIP) analysis of H3K9/14ac and H3K4me3 was conducted using purified CD4(+) T cells, with CD45R(+) B cells as a negative control. Our data revealed that these histone modifications at the VPAC1 promoter did indeed parallel its mRNA levels between T and B lymphocytes, but did not decrease during T cell signaling. Collectively, these data strongly imply a euchromatin nuclear position for the VPAC1 locus irrespective of the activation status of T cells.

Publication types

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

MeSH terms

  • Acetylation
  • Animals
  • Base Sequence
  • CD4-Positive T-Lymphocytes / metabolism*
  • Cell Nucleus / metabolism*
  • Chromatin Immunoprecipitation
  • DNA Primers
  • Down-Regulation
  • Epigenesis, Genetic*
  • Euchromatin / metabolism*
  • Methylation
  • Mice
  • Polymerase Chain Reaction
  • RNA, Messenger / genetics
  • Receptors, Vasoactive Intestinal Polypeptide, Type I / genetics*
  • Signal Transduction
  • Transcription, Genetic

Substances

  • DNA Primers
  • Euchromatin
  • RNA, Messenger
  • Receptors, Vasoactive Intestinal Polypeptide, Type I