Expression and activity of soluble guanylate cyclase in injury and repair of anti-thy1 glomerulonephritis.
BACKGROUND
Activation of soluble guanylate cyclase and generation of cyclic 3',5'-guanosine monophosphate (cGMP) is the main signal transducing event of the L-arginine-nitric oxide pathway. The present study analyzes the expression and activity of the nitric oxide-cGMP signaling cascade in and the effect of the specific soluble guanylate cyclase stimulator Bay 41-2272 on the early injury and subsequent repair phase of acute anti-thy1 glomerulonephritis.


METHODS
Anti-thy1 glomerulonephritis was induced by OX-7 antibody injection in rats. In protocol 1 (injury), Bay 41-2272 was given starting 6 days before antibody injection. One day after disease induction, parameters of mesangial cell injury (glomerular cell number and inducible nitric oxide synthesis) were analyzed. In protocol 2 (repair), Bay 41-2272 treatment was started one day after antibody injection. On day 7, parameters of glomerular repair [glomerular matrix score, expression of transforming growth factor (TGF)-beta1, fibronectin, and plasminogen-activator-inhibitor (PAI)-1, infiltration with macrophages and fibrinogen deposition (indicating platelet localization)] were determined. In both protocols, tail bleeding time, systolic blood pressure, plasma cGMP levels, glomerular mRNA expression of endothelial nitric oxide synthase (eNOS), alpha1 and beta1 soluble guanylate cyclase, and basal and nitric oxide-stimulated glomerular cGMP production were analyzed.


RESULTS
Bay 41-2272 prolonged bleeding time, reduced blood pressure, and increased plasma cGMP levels in both protocols. In the injury experiment, disease induction increased inducible nitric oxide synthesis and reduced glomerular cell number, while expression and activity of soluble guanylate cyclase was almost completely diminished. Bay 41-2272 did not affect parameters of mesangial cell injury and glomerular soluble guanylate cyclase expression and activity. In the repair protocol, expression and activity of soluble guanylate cyclase was markedly increased by disease. Bay 41-2272 further enhanced soluble guanylate cyclase expression and activity. This went along with significant reductions in proteinuria, glomerular matrix accumulation, expression of TGF-beta1, fibronectin, and PAI-1, macrophage infiltration and fibrinogen deposition as compared to the untreated anti-thy1 animals.


CONCLUSIONS
Glomerular nitric oxide signaling via cGMP is markedly impaired during injury of anti-thy1 glomerulonephritis, while it is highly up-regulated during subsequent repair. Further pharmacologic soluble guanylate cyclase stimulation limits glomerular TGF-beta overexpression and matrix expansion, suggesting that the soluble guanylate cyclase enzyme represents an important antifibrotic pathway in glomerular disease.
Peters
Harm
H
Department of Nephrology and Center of Cardiovascular Research, Charité Medicine Berlin, Charité Campus Mitte, Humboldt University, Berlin, Germany. Harm.Peters@charite.de
Wang
Yingrui
Y
Loof
Tanja
T
Martini
Sebastian
S
Kron
Susanne
S
Krämer
Stephanie
S
Neumayer
Hans-H
HH
D000818:Animals; D001760:Bleeding Time; D001794:Blood Pressure; D001835:Body Weight; D006152:Cyclic GMP / Q000097:blood; D005921:Glomerulonephritis / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D006162:Guanylate Cyclase; D066298:In Vitro Techniques; D007518:Isoantibodies / Q000494:pharmacology*; D007678:Kidney Glomerulus / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D008297:Male; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D011720:Pyrazoles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D000071756:Soluble Guanylyl Cyclase; D016212:Transforming Growth Factor beta / Q000378:metabolism; D053773:Transforming Growth Factor beta1
C423582:3-(4-Amino-5-cyclopropylpyrimidine-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo(3,4-b)pyridine; D007518:Isoantibodies; D011720:Pyrazoles; D011725:Pyridines; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C035678:anti-Thy antibody; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP