title: EDNRA variants associate with smooth muscle mRNA levels, cell proliferation rates, and cystic fibrosis pulmonary disease severity.
abstract: Airway inflammation and pulmonary disease are heterogeneous phenotypes in cystic fibrosis (CF) patients, even among patients with the same cystic fibrosis transmembrane conductance regulator (CFTR) genotype. Endothelin, a proinflammatory peptide and smooth muscle agonist, is increased in CF airways, potentially contributing to the pulmonary phenotype. Four cohorts of CF patients were screened for variants in endothelin pathway genes to determine whether any of these variants associated with pulmonary function. An initial cohort of 808 CF patients homozygous for the common CF mutation, DeltaF508, showed significant association for polymorphisms in the endothelin receptor A gene, EDNRA (P = 0.04), but not in the related endothelin genes (EDN1, EDN2, EDN3, or EDNRB) or NOS1, NOS2A, or NOS3. Variants within EDNRA were examined in three additional cohorts of CF patients, 238 patients from Seattle, WA, 303 from Ireland and the U.K., and 228 from Cleveland, OH, for a total of 1,577 CF patients. The three additional groups each demonstrated a significant association between EDNRA 3'-untranslated region (UTR) variant rs5335 and pulmonary function (P = 0.002). At the molecular level, single nucleotide primer extension assays suggest that the effect of the variants is quantitative. EDNRA mRNA levels from cultured primary tracheal smooth muscle cells are greater for the allele that appears to be deleterious to lung function than for the protective allele, suggesting a mechanism by which increased receptor function is harmful to the CF airway. Finally, cell proliferation studies using human airway smooth muscle cells demonstrated that cells homozygous for the deleterious allele proliferate at a faster rate than those homozygous for the protective allele.
authors.affiliation: Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Darrah
authors.forename: Edward
authors.initials: E
authors.lastname: McKone
authors.forename: Clare
authors.initials: C
authors.lastname: O'Connor
authors.forename: Christine
authors.initials: C
authors.lastname: Rodgers
authors.forename: Alan
authors.initials: A
authors.lastname: Genatossio
authors.forename: Sharon
authors.initials: S
authors.lastname: McNamara
authors.forename: Ronald
authors.initials: R
authors.lastname: Gibson
authors.forename: J
authors.initials: J
authors.lastname: Stuart Elborn
authors.forename: Madeleine
authors.initials: M
authors.lastname: Ennis
authors.forename: Charles G
authors.initials: CG
authors.lastname: Gallagher
authors.forename: Noor
authors.initials: N
authors.lastname: Kalsheker
authors.forename: Moira
authors.initials: M
authors.lastname: Aitken
authors.forename: Dawn
authors.initials: D
authors.lastname: Wiese
authors.forename: John
authors.initials: J
authors.lastname: Dunn
authors.forename: Paul
authors.initials: P
authors.lastname: Smith
authors.forename: Rhonda
authors.initials: R
authors.lastname: Pace
authors.forename: Douglas
authors.initials: D
authors.lastname: Londono
authors.forename: Katrina A B
authors.initials: KA
authors.lastname: Goddard
authors.forename: Michael R
authors.initials: MR
authors.lastname: Knowles
authors.forename: Mitchell L
authors.initials: ML
authors.lastname: Drumm
mesh_terms: D000328:Adult; D000483:Alleles; D002460:Cell Line; D049109:Cell Proliferation; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000235:genetics* / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044022:Receptor, Endothelin A / Q000235:genetics* / Q000378:metabolism; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D014132:Trachea / Q000473:pathology; D055815:Young Adult
chemical_list: D012333:RNA, Messenger; D044022:Receptor, Endothelin A