title: Functional variation in the arginine vasopressin 2 receptor as a modifier of human plasma von Willebrand factor levels.
abstract: OBJECTIVE
  Stimulation of arginine vasopressin 2 receptor (V2R) with arginine vasopressin (AVP) results in a rise in von Willebrand factor (VWF) and factor VIII plasma levels. We hypothesized that gain-of-function variations in the V2R gene (AVPR2) would lead to higher plasma levels of VWF and FVIII.
  
  
  RESULTS
  We genotyped the control populations of two population-based studies for four AVPR2 variations: a-245c, G12E, L309L, and S331S. Rare alleles of a-245c, G12E, and S331S, which were in linkage disequilibrium, were associated with higher VWF propeptide, VWF and FVIII levels. The functionality of the G12E variant was studied in stably transfected MDCKII cells, expressing constructs of either 12G-V2R or 12E-V2R. Both V2R variants were fully glycosylated and expressed on the basolateral membrane. The binding affinity of V2R for AVP was increased three-fold in 12E-V2R-green fluorescent protein (GFP) cells, which is in accordance with increased levels of VWF propeptide associated with the 12E variant. The dissociation constant (K(D)) was 4.5 nm [95% confidence interval (CI) 3.6-5.4] for 12E-V2R-GFP and 16.5 nm (95% CI 10.1-22.9) for 12G-V2R-GFP. AVP-induced cAMP generation was enhanced in 12E-V2R-GFP cells.
  
  
  CONCLUSIONS
  The 12E-V2R variant has increased binding affinity for AVP, resulting in increased signal transduction, and is associated with increased levels of VWF propeptide, VWF, and FVIII.
authors.affiliation: Einthoven Laboratory for Experimental Vascular Medicine, Department of Thrombosis and Hemostasis, Leiden University Medical Center, RC Leiden, the Netherlands.
authors.forename: A Y
authors.initials: AY
authors.lastname: Nossent
authors.forename: J H
authors.initials: JH
authors.lastname: Robben
authors.forename: P M T
authors.initials: PM
authors.lastname: Deen
authors.forename: H L
authors.initials: HL
authors.lastname: Vos
authors.forename: F R
authors.initials: FR
authors.lastname: Rosendaal
authors.forename: C J M
authors.initials: CJ
authors.lastname: Doggen
authors.forename: J L
authors.initials: JL
authors.lastname: Hansen
authors.forename: S P
authors.initials: SP
authors.lastname: Sheikh
authors.forename: R M
authors.initials: RM
authors.lastname: Bertina
authors.forename: J C J
authors.initials: JC
authors.lastname: Eikenboom
mesh_terms: D000483:Alleles; D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism; D004285:Dogs; D005169:Factor VIII / Q000032:analysis*; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium; D011485:Protein Binding / Q000235:genetics; D017483:Receptors, Vasopressin / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D014841:von Willebrand Factor / Q000032:analysis*
chemical_list: D017483:Receptors, Vasopressin; D014841:von Willebrand Factor; D001127:Arginine Vasopressin; D005169:Factor VIII