Characterizing function of a trait-associated 3′-UTR variant with transfectedCHGA3′-UTR/luciferase reporter plasmids

Characterizing function of a trait-associated 3′-UTR variant with transfectedCHGA3′-UTR/luciferase reporter plasmids. == Results == CHGA was overexpressed in patients with hypertension, especially hypertensive men, and CHGA predicted catecholamines. cell-transfectedCHGA3′-UTR/luciferase reporter plasmid, the +87T allele associated with lower BP also decreased reporter expression by ~30%. In cultured chromaffin cells, reducing endogenousChgaexpression by si-RNA caused ~2/3 depletion of catecholamine storage vesicles. == Conclusions == Common variant C+87T in theCHGA3′-UTR is a functional polymorphism causally associated with hypertension especially in men of the population, and propose steps (“intermediate phenotypes”) whereby in sex-dependent fashion this genetic variant influences the ultimate disease trait. These observations suggest new molecular strategies to probe the pathophysiology, risk, and rational treatment of hypertension. Keywords:hypertension, chromaffin, catecholamine, adrenal, sympathetic == INTRODUCTION == Chromogranin A (CHGA), a 48-kDa acidic polypeptide (1,2), is the major protein co-stored and co-released with catecholamines from secretory vesicles in adrenal medulla and postganglionic sympathetic axons (3). Catecholamine storage vesicles (or chromaffin granules) of the adrenal medulla contain remarkably high concentrations ofCHGA, catecholamines, ATP, and Ca2+, andCHGAseems GNE-0439 to bind and store both catecholamines and Ca2+(4).CHGAalso binds to the vesicle membrane, where it may influence the release of calcium from secretory granules to the cytosolic exocytotic machinery through the IL3RA inositol 1, 4, 5-trisphosphate receptor/Ca2+channel (5).CHGAis required for formation of catecholamine secretory vesicles in chromaffin cells and its expression may be sufficient to induce a regulated secretory system in nonsecretory cells (6).CHGAis also a pro-hormone that gives rise to biologically active peptides such as the dysglycemic peptide pancreastatin (7,8); the antimicrobial peptide chromacin (9); the vasodilator vasostatin (10); and catestatin that GNE-0439 acts to inhibit catecholamine release (11,12). Essential hypertension is complex trait (13), with contributions from multiple factors: cardiovascular, neuronal, renal, and adrenal. Over the past ~20 years, phenotypic links betweenCHGAand essential (idiopathic, genetic) human (1417) and rodent (18) hypertension have been repeatedly observed. Plasma CHGA concentration correlates with catecholamine release rates (19), and increases in blood pressure caused by the action of catecholamines are likely to be coupled to the formation of dense-core secretory granules, whose biogenesis is regulatedin GNE-0439 vivoby CHGA (20). Recently we systematically identified common genetic variation in humanCHGAby resequencing the gene in several human populations (21); here we explored whether common genetic variation at theCHGAlocus is associated with to blood pressure, beginning with a large population-based sample of extreme blood pressures, in which we found that a 3-UTR polymorphism (C+87T) is associated with substantially to both DBP and SBP. We then established its influence on an earlier pathogenic phenotype (environmental stress-evoked change in BP), and finally documented its effect on gene expression in a transfected reporter program. == Components AND Strategies == == Topics and scientific characterization == == Hypertension == == Medical diagnosis of hypertension == Since hypertension is normally part of a more substantial syndrome, all people of different ancestries had been phenotyped for not merely blood pressure, but associated traits also, both metabolic and renal (on-line Desk Iandon-line Desk II). == Phenotype (CHGA, catecholamine) and BP research == In the initial (solely phenotypic) study, the plasma was assessed by us concentrations of CHGA, norepinephrine, lipids, and creatinine (find below) in n=724 people with regular renal function (serum creatinine 1.5 mg/dl), stratified by blood circulation pressure status: regular blood circulation pressure (documented at <135/<85 mmHg, on no medications), pitched against a medical diagnosis of necessary hypertension (documented at DBP 90 mmHg). Of these with hypertension, 75% had been treated with antihypertensive medicines. Blood pressures had been driven in triplicate (and averaged) in sitting topics with an oscillometric gadget (DynaPulse; PulseMetric, Vista, CA), validated and calibrated as defined previously (22). Through the same go to, the same topics underwent extended (5-minute also,.