title: Comprehensive biochemical analysis of rare prostacyclin receptor variants: study of association of signaling with coronary artery obstruction.
abstract: Currently, pharmacogenetic studies are at an impasse as the low prevalence (<2%) of most variants hinder their pharmacogenetic analysis with population sizes often inadequate for sufficiently powered studies. Grouping rare mutations by functional phenotype rather than mutation site can potentially increase sample size. Using human population-based studies (n = 1,761) to search for dysfunctional human prostacyclin receptor (hIP) variants, we recently discovered 18 non-synonymous mutations, all with frequencies less than 2% in our study cohort. Eight of the 18 had defects in binding, activation, and/or protein stability/folding. Mutations (M113T, L104R, and R279C) in three highly conserved positions demonstrated severe misfolding manifested by impaired binding and activation of cell surface receptors. To assess for association with coronary artery disease, we performed a case-control study comparing coronary angiographic results from patients with reduced cAMP production arising from the non-synonymous mutations (n = 23) with patients with non-synonymous mutations that had no reduction in cAMP (n = 17). Major coronary artery obstruction was significantly increased in the dysfunctional mutation group in comparison with the silent mutations. We then compared the 23 dysfunctional receptor patients with 69 age- and risk factor-matched controls (1:3). This verified the significantly increased coronary disease in the non-synonymous dysfunctional variant cohort. This study demonstrates the potential utility of in vitro functional characterization in predicting clinical phenotypes and represents the most comprehensive characterization of human prostacyclin receptor genetic variants to date.
authors.affiliation: Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Stitham
authors.forename: Eric
authors.initials: E
authors.lastname: Arehart
authors.forename: Larkin
authors.initials: L
authors.lastname: Elderon
authors.forename: Scott R
authors.initials: SR
authors.lastname: Gleim
authors.forename: Karen
authors.initials: K
authors.lastname: Douville
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Kasza
authors.forename: Kristina
authors.initials: K
authors.lastname: Fetalvero
authors.forename: Todd
authors.initials: T
authors.lastname: MacKenzie
authors.forename: John
authors.initials: J
authors.lastname: Robb
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Martin
authors.forename: John
authors.initials: J
authors.lastname: Hwa
mesh_terms: D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D016022:Case-Control Studies; D002522:Chlorocebus aethiops; D017124:Conserved Sequence; D023921:Coronary Stenosis / Q000453:epidemiology / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D014644:Genetic Variation; D006801:Humans; D016285:Iloprost / Q000494:pharmacology; D008297:Male; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D017434:Protein Structure, Tertiary; D044006:Receptors, Epoprostenol; D011982:Receptors, Prostaglandin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012307:Risk Factors; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013329:Structure-Activity Relationship; D014665:Vasodilator Agents / Q000494:pharmacology; D055815:Young Adult
chemical_list: C113936:PTGIR protein, human; D044006:Receptors, Epoprostenol; D011982:Receptors, Prostaglandin; D014665:Vasodilator Agents; D016285:Iloprost