Transcriptional regulation of the human FPR2/ALX gene: evidence of a heritable genetic variant that impairs promoter activity

FASEB J. 2012 Mar;26(3):1323-33. doi: 10.1096/fj.11-198069. Epub 2011 Nov 30.

Abstract

Lipoxin (LX) A(4,) a main endogenous stop-signal of inflammation, activates the G-protein-coupled receptor FPR2/ALX, which triggers potent anti-inflammatory signaling in vivo. Thus, the regulation of FPR2/ALX expression may have pathophysiological and therapeutic relevance. Here, we mapped a nucleotide sequence with strong FPR2/ALX promoter activity. Chromatin immunoprecipitation revealed specificity protein 1 (Sp1) binding to the core promoter. Site-directed mutagenesis of the Sp1 cis-acting element and Sp1 overexpression established that this transcription factor is key for maximal promoter activity, which is instead suppressed by DNA methylation. LXA(4) enhanced FPR2/ALX promoter activity (+74%) and mRNA expression (+87.5%) in MDA-MB231 cells. A single nucleotide mutation (A/G) was detected in the core promoter of one subject with history of cardiovascular disease and of his two daughters. This mutation reduced by ∼35-90% the promoter activity in vitro. Moreover, neutrophils from individuals carrying the A/G variant displayed ∼10- and 3-fold reduction in FPR2/ALX mRNA and protein, respectively, compared with cells from their relatives or healthy volunteers expressing the wild-type allele. These results uncover FPR2/ALX transcriptional regulation and provide the first evidence of mutations that affect FPR2/ALX transcription, thus opening new opportunities for the understanding of the LXA(4)-FPR2/ALX axis in human disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Binding Sites / genetics
  • Blotting, Western
  • Cell Line
  • Cell Line, Tumor
  • DNA Methylation
  • Gene Expression Regulation*
  • Genetic Variation
  • Humans
  • Models, Genetic
  • Molecular Sequence Data
  • Polymorphism, Single Nucleotide
  • Promoter Regions, Genetic / genetics
  • Protein Binding
  • Receptors, Formyl Peptide / genetics*
  • Receptors, Formyl Peptide / metabolism
  • Receptors, Lipoxin / genetics*
  • Receptors, Lipoxin / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sp1 Transcription Factor / metabolism
  • Transcription Initiation Site
  • Transcription, Genetic / genetics*

Substances

  • FPR2 protein, human
  • Receptors, Formyl Peptide
  • Receptors, Lipoxin
  • Sp1 Transcription Factor