Evidence for protein kinase C-mediated activation of Rho-kinase in a porcine model of coronary artery spasm.
OBJECTIVE
We have recently demonstrated that protein kinase C (PKC) and Rho-kinase play important roles in coronary vasospasm in a porcine model. However, it remains to be examined whether there is an interaction between the two molecules to cause the spasm.


RESULTS
A segment of left porcine coronary artery was chronically treated with IL-1beta-bound microbeads in vivo. Two weeks after the operation, phorbol ester caused coronary spasm in vivo and coronary hypercontractions in vitro at the IL-1beta-treated segment; both were significantly inhibited by hydroxyfasudil, a specific Rho-kinase inhibitor. Guanosine 5'-[gamma-thio]triphosphate (GTPgammaS), which activates Rho with a resultant activation of Rho-kinase, enhanced Ca2+ sensitization of permeabilized vascular smooth muscle cells, which were resistant to the blockade of PKC by calphostin C. The GTPgammaS-induced Ca2+ sensitization was greater in the spastic segment than in the control segment. Western blot analysis revealed that only PKCdelta isoform was activated during the hypercontraction.


CONCLUSIONS
These results demonstrate that PKC and Rho-kinase coexist on the same intracellular signaling pathway, with PKC located upstream on Rho-kinase, and that among the PKC isoforms, only PKCdelta may be involved. Thus, the strategy to inhibit Rho-kinase rather than PKC may be a more specific and useful treatment for coronary spasm.
Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku Fukuoka 812-8582, Japan.
Tadashi
T
Kandabashi
Hiroaki
H
Shimokawa
Kenji
K
Miyata
Ikuko
I
Kunihiro
Yasuhiro
Y
Eto
Kunio
K
Morishige
Yasuharu
Y
Matsumoto
Kazuo
K
Obara
Koichi
K
Nakayama
Shosuke
S
Takahashi
Akira
A
Takeshita
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects; D003329:Coronary Vasospasm / Q000201:enzymology* / Q000378:metabolism; D003331:Coronary Vessels / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D004195:Disease Models, Animal; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000737:chemistry / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D013552:Swine; D054460:rho-Associated Kinases
D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; C431085:hydroxyfasudil; D015240:Phorbol 12,13-Dibutyrate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D011493:Protein Kinase C; D020559:Monomeric GTP-Binding Proteins; D002118:Calcium