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

• Published in: The FASEB journal Vol. 26; no. 3; p. 1323
• Main Authors: Simiele, Felice, Recchiuti, Antonio, Mattoscio, Domenico, De Luca, Antonella, Cianci, Eleonora, Franchi, Sara, Gatta, Valentina, Parolari, Alessandro, Werba, Josè Pablo, Camera, Marina, Favaloro, Bartolo, Romano, Mario
• Format: Journal Article
• Language: English
• Published: United States 01.03.2012
• Subjects: 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
• ISSN: 1530-6860
• DOI: 10.1096/fj.11-198069

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.