title: Reduced expression of regulator of G-protein signaling 2 (RGS2) in hypertensive patients increases calcium mobilization and ERK1/2 phosphorylation induced by angiotensin II.
abstract: BACKGROUND
  RGS2 (regulators of G-protein signaling) is a negative regulator of Galphaq protein signaling, which mediates the action of several vasoconstrictors. RGS2-deficient mouse line exhibits a hypertensive phenotype and a prolonged response to vasoconstrictors.
  
  
  OBJECTIVE
  To compare RGS2 expression in peripheral blood mononuclear cells (PBMs) and cultured fibroblasts from normotensive subjects and hypertensive patients.
  
  
  METHODS
  PBMs were isolated from 100 controls and 150 essential hypertensives. Additionally, fibroblasts were isolated from skin biopsy of 11 normotensives and 12 hypertensives and cultured up to the third passage. Quantitative mRNA and protein RGS2 expression were performed by real-time quantitative reverse transcriptase-polymerase chain reaction and by immunoblotting, respectively. Free Ca measurement was performed in monolayers of 24-h serum-deprived cells, using FURA-2 AM. Phosphorylation of the extracellular signal-regulated kinases ERK1/2 was measured by immunoblotting. Polymorphism (C1114G) in the 3' untranslated region of the RGS2 gene was investigated by direct sequencing and real-time polymerase chain reaction (PCR).
  
  
  RESULTS
  RGS2 mRNA expression was significantly lower in PBM and in fibroblasts from hypertensives, in comparison to normotensives. C1114G polymorphism was associated with RGS2 expression, with the lowest values in GG hypertensives. The 1114G allele frequency was increased in hypertensives compared with normotensives. Angiotensin II-stimulated intracellular Ca increase and ERK1/2 phosphorylation were higher in fibroblasts from hypertensive patients compared with control subjects, and in those with the G allele, independently of the blood pressure status. The angiotensin II-stimulated Ca mobilization and ERK1/2 phosphorylation were negatively correlated with RGS2 mRNA expression.
  
  
  CONCLUSIONS
  Low expression of RGS2 contributes to increased G-protein-coupled signaling in hypertensive patients. The allele G is associated with low RGS2 expression and blood pressure increase in humans.
authors: Department of Clinical and Experimental Medicine, University of Padova, Italy. andrea.semplicini@unipd.it
authors: Andrea
authors: A
authors: Semplicini
authors: Livia
authors: L
authors: Lenzini
authors: Michelangelo
authors: M
authors: Sartori
authors: Italia
authors: I
authors: Papparella
authors: Lorenzo A
authors: LA
authors: Calò
authors: Elisa
authors: E
authors: Pagnin
authors: Giacomo
authors: G
authors: Strapazzon
authors: Clara
authors: C
authors: Benna
authors: Rodolfo
authors: R
authors: Costa
authors: Angelo
authors: A
authors: Avogaro
authors: Giulio
authors: G
authors: Ceolotto
authors: Achille C
authors: AC
authors: Pessina