title: Decreased transcriptional activity of calcium-sensing receptor gene promoter 1 is associated with calcium nephrolithiasis.
abstract: BACKGROUND
  CaSR gene is a candidate for calcium nephrolithiasis. Single-nucleotide polymorphisms (SNPs) encompassing its regulatory region were associated with calcium nephrolithiasis.
  
  
  OBJECTIVE
  We tested SNPs in the CaSR gene regulatory region associated with calcium nephrolithiasis and their effects in kidney.
  
  
  METHODS
  One hundred sixty-seven idiopathic calcium stone formers and 214 healthy controls were genotyped for four CaSR gene SNPs identified by bioinformatics analysis as modifying transcription factor binding sites. Strontium excretion after an oral load was tested in 55 stone formers. Transcriptional activity induced by variant alleles at CaSR gene promoters was compared by luciferase reporter gene assay in HEK-293 and HKC-8 cells. CaSR and claudin-14 mRNA levels were measured by real-time PCR in 107 normal kidney medulla samples and compared in patients with different CaSR genotype.
  
  
  RESULTS
  Only rs6776158 (A>G), located in the promoter 1, was associated with nephrolithiasis. Its minor G allele was more frequent in stone formers than controls (37.8% vs 26.4%, P = .001). A reduced strontium excretion was observed in GG homozygous stone formers. Luciferase fluorescent activity was lower in cells transfected with the promoter 1 including G allele at rs6776158 than cells transfected with the A allele. CaSR mRNA levels were lower in kidney medulla samples from homozygous carriers for the G allele at rs6776158 than carriers for the A allele. Claudin-14 mRNA levels were also lower in GG homozygous subjects.
  
  
  CONCLUSIONS
  Minor allele at rs6776158 may predispose to calcium stones by decreasing transcriptional activity of the CaSR gene promoter 1 and CaSR expression in kidney tubules.
authors.affiliation: Nephrology and Dialysis Unit, San Raffaele Hospital Instituto di Ricovero e Cura a Carattere Scientifico, 20132 Milan, Italy. vezzoli.giuseppe@hsr.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Vezzoli
authors.forename: Annalisa
authors.initials: A
authors.lastname: Terranegra
authors.forename: Andrea
authors.initials: A
authors.lastname: Aloia
authors.forename: Teresa
authors.initials: T
authors.lastname: Arcidiacono
authors.forename: Luciano
authors.initials: L
authors.lastname: Milanesi
authors.forename: Ettore
authors.initials: E
authors.lastname: Mosca
authors.forename: Alessandra
authors.initials: A
authors.lastname: Mingione
authors.forename: Donatella
authors.initials: D
authors.lastname: Spotti
authors.forename: Daniele
authors.initials: D
authors.lastname: Cusi
authors.forename: Jianghui
authors.initials: J
authors.lastname: Hou
authors.forename: Geoffrey N
authors.initials: GN
authors.lastname: Hendy
authors.forename: Laura
authors.initials: L
authors.lastname: Soldati
authors.forename: Vera
authors.initials: V
authors.lastname: Paloschi
authors.forename: Elena
authors.initials: E
authors.lastname: Dogliotti
authors.forename: Caterina
authors.initials: C
authors.lastname: Brasacchio
authors.forename: Giacomo
authors.initials: G
authors.lastname: Dell'Antonio
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
authors.forename: Roberto
authors.initials: R
authors.lastname: Bertini
authors.forename: Piera
authors.initials: P
authors.lastname: Bellinzoni
authors.forename: Giorgio
authors.initials: G
authors.lastname: Guazzoni
authors.forename: Loris
authors.initials: L
authors.lastname: Borghi
authors.forename: Angela
authors.initials: A
authors.lastname: Guerra
authors.forename: Franca
authors.initials: F
authors.lastname: Allegri
authors.forename: Andrea
authors.initials: A
authors.lastname: Ticinesi
authors.forename: Tiziana
authors.initials: T
authors.lastname: Meschi
authors.forename: Antonio
authors.initials: A
authors.lastname: Nouvenne
authors.forename: Antonio
authors.initials: A
authors.lastname: Lupo
authors.forename: Antonia
authors.initials: A
authors.lastname: Fabris
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gambaro
authors.forename: Pasquale
authors.initials: P
authors.lastname: Strazzullo
authors.forename: Domenico
authors.initials: D
authors.lastname: Rendina
authors.forename: Giampaolo
authors.initials: G
authors.lastname: De Filippo
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Brandi
authors.forename: Emanuele
authors.initials: E
authors.lastname: Croppi
authors.forename: Luisella
authors.initials: L
authors.lastname: Cianferotti
authors.forename: Alberto
authors.initials: A
authors.lastname: Trinchieri
authors.forename: Renata
authors.initials: R
authors.lastname: Caudarella
authors.forename: Adamasco
authors.initials: A
authors.lastname: Cupisti
authors.forename: Franca
authors.initials: F
authors.lastname: Anglani
authors.forename: Dorella
authors.initials: D
authors.lastname: Del Prete
mesh_terms: D000328:Adult; D000483:Alleles; D016022:Case-Control Studies; D005260:Female; D005838:Genotype; D057809:HEK293 Cells; D006801:Humans; D053565:Hypercalciuria / Q000235:genetics / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D016297:Mutagenesis, Site-Directed; D053040:Nephrolithiasis / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic / Q000235:genetics*; D044169:Receptors, Calcium-Sensing / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D044169:Receptors, Calcium-Sensing