Cardiovascular effects of a novel potent and highly selective azaindole-based inhibitor of Rho-kinase.
OBJECTIVE
Rho-kinase (ROCK) has been implicated in the pathophysiology of altered vasoregulation leading to hypertension. Here we describe the pharmacological characterization of a potent, highly selective and orally active ROCK inhibitor, the derivative of a class of azaindoles, azaindole 1 (6-chloro-N4-{3,5-difluoro-4-[(3-methyl-1H-pyrrolo[2,3-b]pyridin-4-yl)oxy]-phenyl}pyrimidine-2,4-diamine).


METHODS
Pharmacological characterization of azaindole 1 was performed with human recombinant ROCK in vitro. Vasodilator activity was determined using isolated vessels in vitro and different animal models in vivo.


RESULTS
This compound inhibited the ROCK-1 and ROCK-2 isoenzymes with IC50 s of 0.6 and 1.1 nM in an ATP-competitive manner. Although ATP-competitive, azaindole 1 was inactive against 89 kinases (IC50>10 microM) and showed only weak activity against an additional 21 different kinases (IC50=1-10 microM). Only the kinases TRK und FLT3 were inhibited by azaindole 1 in the sub-micromolar range, albeit with IC50 values of 252 and 303 nM, respectively. In vivo, azaindole 1 lowered blood pressure dose-dependently after i.v. administration in anaesthetized normotensive rats. In conscious normotensive and spontaneously hypertensive rats azaindole 1 induced a dose-dependent decrease in blood pressure after oral administration without inducing a significant reflex increase in heart rate. In anaesthetized dogs, azaindole 1 induced vasodilatation with a moderately elevated heart rate.


CONCLUSIONS
Azaindole 1 is representative of a new class of selective and potent ROCK inhibitors and is a valuable tool for the elucidation of the role of ROCK in the cardiovascular system.
Kast
R
R
Cardiovascular Research, Bayer HealthCare Pharma Research Center, Wuppertal, Germany. raimund.kast@bayerhealthcare.com
Schirok
H
H
Figueroa-Pérez
S
S
Mittendorf
J
J
Gnoth
M J
MJ
Apeler
H
H
Lenz
J
J
Franz
J K
JK
Knorr
A
A
Hütter
J
J
Lobell
M
M
Zimmermann
K
K
Münter
K
K
Augstein
K H
KH
Ehmke
H
H
Stasch
J P
JP
D000284:Administration, Oral; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002319:Cardiovascular System / Q000187:drug effects*; D002478:Cells, Cultured; D003198:Computer Simulation; D064550:Death-Associated Protein Kinases; D003959:Diamines / Q000494:pharmacology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D051379:Mice; D023421:Models, Animal; D008958:Models, Molecular; D009924:Organ Culture Techniques; D010766:Phosphorylation; D016133:Polymerase Chain Reaction / Q000379:methods; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
C526226:(6-chloro-N4-(3,5-difluoro-4-((3-methyl-1H-pyrrolo(2,3-b)pyridin-4-yl)oxy)-phenyl)pyrimidine-2,4-diamine); D051017:Apoptosis Regulatory Proteins; D003959:Diamines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D011994:Recombinant Proteins; D014665:Vasodilator Agents; D064550:Death-Associated Protein Kinases; D054460:rho-Associated Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases