title: Analyses of RANK and RANKL in the post-GWAS context: functional evidence of vitamin D stimulation through a RANKL distal region.
abstract: Over the past decade, many genome-wide association studies (GWAs) and meta-analyses have identified genes and regions involved in osteoporotic phenotypes. Nevertheless, the large majority of these results were not tested at any functional level. GWA-associated single-nucleotide polymorphisms (SNPs) near candidate genes such as RANK and RANKL suggest that these SNPs and/or other variants nearby may be involved in bone phenotype determination. This study focuses on SNPs along these two genes, which encode proteins with a well-established role in the bone remodeling equilibrium. Thirty-three SNPs, chosen for their location in evolutionary conserved regions or replicated from previous studies, were genotyped in the BARCOS cohort of 1061 postmenopausal women and tested for association with osteoporotic phenotypes. SNP rs9594738, which lies 184 kb upstream of the RANKL gene, was the only SNP found to be associated with a bone phenotype (dominant model: beta coefficient = -0.034, p = 1.5 × 10(-4) , for lumbar spine bone mineral density). Functional experiments exploring a distal region (DR) of 831 bp that harbors this SNP in a centered position (nt 470) demonstrated its capacity to inhibit the RANKL promoter in reporter gene assays. Remarkably, this DR inhibition was significantly reduced in the presence of vitamin D. In conclusion, the GWA-associated SNP rs9594738 lies in a region involved in transcription regulation through which vitamin D could be regulating RANKL expression and bone mineral density.
authors.affiliation: URFOA, IMIM (Institut Hospital del Mar d'Investigacions Mèdiques), Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), Barcelona, Spain.
authors.forename: Guy
authors.initials: G
authors.lastname: Yoskovitz
authors.forename: Natalia
authors.initials: N
authors.lastname: Garcia-Giralt
authors.forename: Maria
authors.initials: M
authors.lastname: Rodriguez-Sanz
authors.forename: Roser
authors.initials: R
authors.lastname: Urreizti
authors.forename: Robert
authors.initials: R
authors.lastname: Guerri
authors.forename: Sergi
authors.initials: S
authors.lastname: Ariño-Ballester
authors.forename: Daniel
authors.initials: D
authors.lastname: Prieto-Alhambra
authors.forename: Leonardo
authors.initials: L
authors.lastname: Mellibovsky
authors.forename: Daniel
authors.initials: D
authors.lastname: Grinberg
authors.forename: Xavier
authors.initials: X
authors.lastname: Nogues
authors.forename: Susana
authors.initials: S
authors.lastname: Balcells
authors.forename: Adolfo
authors.initials: A
authors.lastname: Diez-Perez
mesh_terms: D001483:Base Sequence; D015519:Bone Density / Q000187:drug effects / Q000235:genetics; D003198:Computer Simulation; D021901:DNA, Intergenic / Q000235:genetics; D005260:Female; D050723:Fractures, Bone / Q000235:genetics; D005787:Gene Frequency / Q000235:genetics; D017930:Genes, Reporter; D020022:Genetic Predisposition to Disease; D015894:Genome, Human / Q000235:genetics; D055106:Genome-Wide Association Study; D006801:Humans; D008875:Middle Aged; D008957:Models, Genetic; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D053245:RANK Ligand / Q000235:genetics*; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000235:genetics*; D014807:Vitamin D / Q000494:pharmacology*
chemical_list: D021901:DNA, Intergenic; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505686:TNFRSF11A protein, human; C505688:TNFSF11 protein, human; D014807:Vitamin D
keywords: BONE MINERAL DENSITY; OSTEOPOROSIS; RANK; RANKL; VITAMIN D