Epigenetic suppression of iNOS expression in human endothelial cells: A potential role of Ezh2-mediated H3K27me3

Genomics. 2016 Apr;107(4):145-9. doi: 10.1016/j.ygeno.2016.02.002. Epub 2016 Feb 4.

Abstract

Objective: Cytokines strongly induce expression of the inducible nitric oxide synthase (iNOS) in rodent but not in human endothelial cells. We recently identified NOS2 as a potential target of the histone methyltransferase enhancer of zeste homolog 2 which mediates trimethylation of histone 3 at lysine 27 (H3K27me3).

Methods and results: Compared to an unspecific IgG control, chromatin immunoprecipitation using a H3K27me3-specific antibody followed by DNA quantification by PCR showed a strong DNA enrichment - indicating that NOS2 is associated with H3K27me3 in human umbilical vein endothelial cells (HUVEC). siRNA-mediated knock down of Ezh2 diminished NOS2 DNA enrichment - suggesting that the association of NOS2 with H3K27me3 is mediated by Ezh2. Ezh2 knock down, however, was not sufficient to increase iNOS expression after stimulation of HUVEC.

Conclusion: NOS2 is associated with Ezh2-mediated H3K27me3 in HUVEC. This might contribute to an epigenetic suppression of iNOS inducibility in human endothelial cells.

Keywords: Endothelial cells; Enhancer of zeste homolog 2; Epigenetic regulation; H3K27me3; Nitric oxide synthase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Enhancer of Zeste Homolog 2 Protein / genetics
  • Enhancer of Zeste Homolog 2 Protein / metabolism*
  • Epigenesis, Genetic*
  • Gene Knockdown Techniques
  • Histones / metabolism*
  • Human Umbilical Vein Endothelial Cells / metabolism
  • Humans
  • Nitric Oxide Synthase Type II / genetics
  • Nitric Oxide Synthase Type II / metabolism*
  • RNA, Small Interfering

Substances

  • Histones
  • RNA, Small Interfering
  • NOS2 protein, human
  • Nitric Oxide Synthase Type II
  • EZH2 protein, human
  • Enhancer of Zeste Homolog 2 Protein