Rho kinase and PAI-1 in Bartter's/Gitelman's syndromes: relationship to angiotensin II signaling.
OBJECTIVE
Angiotensin II (Ang II)-mediated activation of Rho kinase (ROK) is involved in the pathophysiology of hypertension and cardiovascular remodeling. ROK also controls plasminogen activator inhibitor-1 (PAI-1) which promotes vascular fibrosis contributing to atherogenesis. Bartter's and Gitelman's syndromes (BS/GS) are useful models to investigate abnormalities of vascular tone regulation, due to their reduced short- and long-term signaling pathways of Ang II. This study evaluated, using BS/GS as a model, ROK and PAI-1 gene and protein expression and the effect of Ang II co-incubation on ROK and PAI-1 gene and protein expression.


METHODS
We measured ROK and PAI-1 gene and protein expression [reverse transcription-polymerase chain reaction (RT-PCR) and Western blot] in mononuclear cells (PBM) from one BS and eight GS patients. The effect of Ang II on ROK and PAI-1 gene and protein expression was also evaluated and compared with 10 controls. ROK gene and protein expression was reduced in BS/GS [0.47 +/- 0.11 densitometric units (d.u.) versus 0.70 +/- 0.04 d.u., P = 0.0038 and 0.39 +/- 0.07 d.u. versus 0.55 +/- 0.07 d.u., P = 0.0026, respectively]. The basal level of PAI-1 gene and protein expression did not differ (0.40 +/- 0.03 d.u. versus 0.39 +/- 0.02 d.u. and 0.81 +/- 0.02 d.u. versus 0.83 +/- 0.02 d.u., respectively). Ang II increased ROK and PAI-1 gene and protein expression only in controls: from 0.70 +/- 0.04 to 0.90 +/- 0.06 d.u., P = 0.007 (ROK mRNA); from 0.55 +/- 0.07 to 0.86 +/- 0.07 d.u., P = 0.0005 (ROK protein); from 0.40 +/- 0.02 to 0.63 +/- 0.03 d.u., P = 0.001 (PAI-1 mRNA); and from 0.83 +/- 0.02 to 1.34 +/- 0.16 d.u., P = 0.0023 (PAI-1 protein).


CONCLUSIONS
This study confirms BS/GS as a human model to investigate interrelated systems involved in the pathophysiology of hypertension and throws more light on the cellular mechanisms of BS/GS reduced Ang II short- and long-term signaling pathways.
Pagnin
Elisa
E
Department of Clinical and Experimental Medicine, Clinica Medica 4, University of Padova, Italy.
Davis
Paul A
PA
Sartori
Michelangelo
M
Semplicini
Andrea
A
Pessina
Achille C
AC
Calò
Lorenzo A
LA
D000328:Adult; D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D001477:Bartter Syndrome / Q000378:metabolism*; D016022:Case-Control Studies; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007674:Kidney Diseases / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D013577:Syndrome; D054460:rho-Associated Kinases
D047908:Intracellular Signaling Peptides and Proteins; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D000804:Angiotensin II; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases