title: Increased level of p63RhoGEF and RhoA/Rho kinase activity in hypertensive patients.
abstract: OBJECTIVE
  p63RhoGEF, a guanine nucleotide exchange factor, has been reported 'in vitro' as key mediator of the angiotensin II-induced RhoA/Rho kinase activation leading to vasoconstriction and cardiovascular remodeling. We assessed p63RhoGEF gene and protein expression and RhoA/Rho kinase activity in essential hypertensive and Bartter's and Gitelman's syndrome patients, a human model opposite to hypertension; the latter have, in fact, increased plasma angiotensin II, activation of the renin-angiotensin system, yet normotension/hypotension, reduced peripheral resistance and lack of cardiovascular remodeling due to an endogenously blunted angiotensin II type 1 receptor signaling.
  
  
  METHODS
  Mononuclear cell p63RhoGEF gene and protein expression and the phosphorylation status of the myosin phosphatase target protein-1 (MYPT-1), marker of Rho kinase activity, were assessed in essential hypertensive patients, Bartter's/Gitelman's patients and healthy individuals by quantitative real-time PCR and western blot.
  
  
  RESULTS
  p63RhoGEF mRNA and protein level and MYPT-1 phosphorylation status were higher in hypertensive patients and lower in Bartter's/Gitelman's patients compared with healthy individuals: p63RhoGEF mRNA level: 0.59 ± 0.17 ΔΔCt vs. 0.37 ± 0.17 vs. 0.20 ± 0.19, analysis of variance (ANOVA): P <0.016; p63RhoGEF protein level 1.35 ± 0.14 vs. 1.09 ± 0.05 vs. 0.90 ± 0.09 densitometric units, ANOVA: P <0.0001; MYPT-1: 1.39 ± 0.34 vs. 1.01 ± 0.12 vs. 0.81 ± 0.06, ANOVA: P < 0.0001. p63RhoGEF mRNA was significantly correlated with both SBP and DBP in both hypertensive patients (R = 0.79, P < 0.02 and R = 0.78, P < 0.02) and in Bartter's syndrome/Gitelman's syndrome patients (R = 0.87, P < 0.001 and R = 0.86, P < 0.001), respectively.
  
  
  CONCLUSIONS
  Increased p63RhoGEF mRNA and protein level and Rho kinase activity are shown for the first time in essential hypertensive patients, whereas the opposite was found in Bartter's/Gitelman's patients, a human model opposite to hypertension. These results combined with other 'in-vitro' studies strongly support the crucial importance of p63RhoGEF in Ang II-mediated signaling involved in the regulation of blood pressure and its long-term complications in humans.
authors.affiliation: aDepartment of Medicine, University of Padova, Padova, Italy bDepartment of Nutrition, University of California, Davis, California, USA.
authors.forename: Lorenzo A
authors.initials: LA
authors.lastname: Calò
authors.forename: Paul A
authors.initials: PA
authors.lastname: Davis
authors.forename: Elisa
authors.initials: E
authors.lastname: Pagnin
authors.forename: Lucia
authors.initials: L
authors.lastname: Dal Maso
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maiolino
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Seccia
authors.forename: Achille C
authors.initials: AC
authors.lastname: Pessina
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Rossi
mesh_terms: D000328:Adult; D000804:Angiotensin II / Q000502:physiology; D001477:Bartter Syndrome / Q000097:blood / Q000235:genetics / Q000503:physiopathology; D001794:Blood Pressure; D016022:Case-Control Studies; D005260:Female; D053579:Gitelman Syndrome / Q000097:blood / Q000235:genetics / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000235:genetics / Q000503:physiopathology; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D043263:Myosin-Light-Chain Phosphatase / Q000097:blood / Q000737:chemistry; D010766:Phosphorylation; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics; D064067:Rho Guanine Nucleotide Exchange Factors / Q000097:blood* / Q000235:genetics; D015398:Signal Transduction; D064486:Solute Carrier Family 12, Member 3 / Q000235:genetics; D054460:rho-Associated Kinases / Q000097:blood*; D020742:rhoA GTP-Binding Protein / Q000097:blood*
chemical_list: C475063:ARHGEF25 protein, human; D012333:RNA, Messenger; D064067:Rho Guanine Nucleotide Exchange Factors; C578874:SLC12A3 protein, human; D064486:Solute Carrier Family 12, Member 3; D000804:Angiotensin II; C066737:RHOA protein, human; D054460:rho-Associated Kinases; D043263:Myosin-Light-Chain Phosphatase; C490372:PPP1R12A protein, human; D020742:rhoA GTP-Binding Protein