title: A variant in a cis-regulatory element enhances claudin-14 expression and is associated with pediatric-onset hypercalciuria and kidney stones.
abstract: The greatest risk factor for kidney stones is hypercalciuria, the etiology of which is largely unknown. A recent genome-wide association study (GWAS) linked hypercalciuria and kidney stones to a claudin-14 (CLDN14) risk haplotype. However, the underlying molecular mechanism was not delineated. Recently, renal CLDN14 expression was found to increase in response to increased plasma calcium, thereby inducing calciuria. We hypothesized therefore that some children with hypercalciuria and kidney stones harbor a CLDN14 variant that inappropriately increases gene expression. To test this hypothesis, we sequenced the CLDN14 risk haplotype in a cohort of children with idiopathic hypercalciuria and kidney stones. An intronic SNP was more frequent in affected children. Dual luciferase and cell-based assays demonstrated increased reporter or CLDN14 expression when this polymorphism was introduced. In silico studies predicted the SNP introduced a novel insulinoma-associated 1 (INSM1) transcription factor binding site. Consistent with this, repeating the dual luciferase assay in the presence of INSM1 further increased reporter expression. Our data suggest that children with the INSM1 binding site within the CLDN14 risk haplotype have a higher likelihood of hypercalciuria and kidney stones. Enhanced CLDN14 expression may play a role in the pathophysiology of their hypercalciuria.
authors.affiliation: Department of Pediatrics, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: Megan E
authors.initials: ME
authors.lastname: Ure
authors.affiliation: Department of Pediatrics, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: Emma
authors.initials: E
authors.lastname: Heydari
authors.affiliation: Department of Physiology, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: Wanling
authors.initials: W
authors.lastname: Pan
authors.affiliation: Depratment of Cell Biology, University of Kaiserslautern, Kaiserslautern, 67663, Germany.
authors.forename: Ajay
authors.initials: A
authors.lastname: Ramesh
authors.affiliation: Department of Pediatrics, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: Sabah
authors.initials: S
authors.lastname: Rehman
authors.affiliation: Department of Pediatrics, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Morgan
authors.affiliation: Department of Pediatrics, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: Maury
authors.initials: M
authors.lastname: Pinsk
authors.affiliation: Department of Pediatrics, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 0W8, Canada.
authors.forename: Robin
authors.initials: R
authors.lastname: Erickson
authors.affiliation: Depratment of Cell Biology, University of Kaiserslautern, Kaiserslautern, 67663, Germany.
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Herrmann
authors.affiliation: Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, 5000, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Dimke
authors.affiliation: Department of Pediatrics, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Cordat
authors.affiliation: The Hospital for Sick Children, Toronto, Ontario, M5G 1×8, Canada.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Lemaire
authors.affiliation: Department of Medical Genetics, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Walter
authors.affiliation: Department of Pediatrics, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.|Department of Physiology, The University of Alberta, Edmonton, Alberta, T6G 2R7, Canada.
authors.forename: R Todd
authors.initials: RT
authors.lastname: Alexander
mesh_terms: D000293:Adolescent; D001665:Binding Sites / Q000235:genetics; D002118:Calcium / Q000097:blood; D002648:Child; D002675:Child, Preschool; D057167:Claudins / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006801:Humans; D053565:Hypercalciuria / Q000150:complications / Q000235:genetics* / Q000473:pathology; D007223:Infant; D007669:Kidney Calculi / Q000150:complications / Q000235:genetics* / Q000473:pathology; D008297:Male; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*
chemical_list: D057167:Claudins; D012097:Repressor Proteins; C087342:INSM1 protein, human; D002118:Calcium; C422064:claudin 14
keywords: claudin-14; hypercalciuria; pediatric kidney stones