title: cAMP-dependent regulation of RhoA/Rho-kinase attenuates detrusor overactivity in a novel mouse experimental model.
abstract: To investigate detrusor function and cAMP activation as a possible target for detrusor overactivity in an experimental model lacking a key denitrosylation enzyme, S-nitrosoglutathione reductase (GSNOR).
  
  
  
  GSNOR-deficient (GSNOR-/-) (n = 30) and wild-type (WT) mice (n = 26) were treated for 7 days with the cAMP activator, colforsin (1 mg/kg), or vehicle intraperitoneally. Cystometric studies or molecular analyses of bladder specimens were performed. Bladder function indices and expression levels of proteins that regulate detrusor relaxation (nitric oxide synthase pathway) or contraction (RhoA/Rho-kinase pathway) and oxidative stress were assessed. For statistical analysis the Student's t-test and one-way analysis of variance were used.
  
  
  
  GSNOR-/-mice had significantly higher (P < 0.05) voiding and non-voiding contraction frequencies compared to WT mice (Cohen's effect size values d = 1.82 and 2.52, respectively). Colforsin normalised these abnormalities (Cohen's effect size values d = 1.85 and 1.28, respectively). Western blot analyses showed an up-regulation of the RhoA/Rho-kinase pathway reflected by significantly higher (P < 0.05) phosphorylated myosin phosphatase target subunit 1 (P-MYPT-1) expression in GSNOR-/-mouse bladders, which was reversed by colforsin treatment. There was a higher level (P < 0.05) of gp91phoxexpression in the bladders of GSNOR-/-mice without significant change after colforsin treatment. Neuronal and endothelial nitric oxide synthase phosphorylation on Ser-1412 and Ser-1177, respectively, did not differ between GSNOR-/-and WT mouse bladders irrespective of colforsin treatment.
  
  
  
  Impaired denitrosylation is associated with detrusor overactivity, which is linked with upregulated RhoA/Rho-kinase signalling. Colforsin reverses physiological and molecular abnormalities. This study describes a novel model of detrusor overactivity and suggests a possible basis for its treatment.
authors.affiliation: The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, MD, USA.
authors.forename: William
authors.identifier: 0000-0003-1683-0079
authors.initials: W
authors.lastname: Akakpo
authors.affiliation: The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, MD, USA.
authors.forename: Biljana
authors.initials: B
authors.lastname: Musicki
authors.affiliation: The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, MD, USA.
authors.forename: Arthur L
authors.initials: AL
authors.lastname: Burnett
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D010413:Penis / Q000294:innervation / Q000473:pathology*; D015398:Signal Transduction; D015854:Up-Regulation; D053201:Urinary Bladder, Overactive / Q000473:pathology*; D020741:rho GTP-Binding Proteins / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein
chemical_list: D009569:Nitric Oxide; D054460:rho-Associated Kinases; C526380:RhoA protein, mouse; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein
keywords: animal model; cystometry; nitric oxide; overactive bladder; transnitrosylation