Inhibition of Rho-kinase leads to rapid activation of phosphatidylinositol 3-kinase/protein kinase Akt and cardiovascular protection.
OBJECTIVE
Rho-kinase activity is increased in cardiovascular diseases and in patients with cardiovascular risk factors. However, it is not known whether inhibition of Rho-kinase could lead to cardiovascular protection and, if so, by what mechanism.


RESULTS
In human endothelial cells, the Rho-kinase inhibitor, hydroxyfasudil (HF) (1 to 100 micromol/L), increased Akt serine-473 phosphorylation within 15 minutes, leading to a 2.2-fold and 4.0-fold increase in Akt kinase activity and nitric oxide (NO) release, respectively. Activation of Akt and eNOS by HF was completely blocked by the phosphatidylinositol 3-kinase (PI3-kinase) inhibitor, LY294002 (10 micromol/L). To determine the physiological relevance of this pathway, we used 2 models of ischemia-reperfusion (I/R) injury. Acute administration of fasudil (10 mg/kg, intraperitoneal, 1 hour before ischemia) decreased leukocyte recruitment and adhesion to the mesenteric endothelium after I/R injury in wild-type but not eNOS-/- mice. Similarly, treatment with fasudil decreased myocardial infarct size by 38% in rats subjected to transient coronary artery occlusion. Cotreatment with 2 PI3-kinase inhibitors, wortmannin and LY294002, or the eNOS inhibitor, L-NAME, blocked the cardiovascular protective effects of fasudil.


CONCLUSIONS
Inhibition of Rho-kinase leads to the activation of the PI3-kinase/Akt/eNOS pathway and cardiovascular protection. These findings suggest that Rho-kinase may play an important role in mediating the inflammatory response to I/R injury.
Vascular Medicine Research Unit, Brigham & Women's Hospital and Harvard Medical School, Cambridge, Mass 02139, USA.
Sebastian
S
Wolfrum
Andreas
A
Dendorfer
Yoshiyuki
Y
Rikitake
Timothy J
TJ
Stalker
Yulan
Y
Gong
Rosario
R
Scalia
Peter
P
Dominiak
James K
JK
Liao
D000818:Animals; D002319:Cardiovascular System / Q000201:enzymology*; D004789:Enzyme Activation / Q000502:physiology; D006331:Heart Diseases / Q000517:prevention & control; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017208:Rats, Wistar; D014652:Vascular Diseases / Q000517:prevention & control; D054460:rho-Associated Kinases
D047908:Intracellular Signaling Peptides and Proteins; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D054460:rho-Associated Kinases; C496314:NOS3 protein, human; C496315:Nos3 protein, mouse; C496316:Nos3 protein, rat; C494918:AKT1 protein, human; C494920:Akt1 protein, rat