Effects of protein kinase inhibitors on angiotensin II-stimulated cell growth in cultured rat aortic smooth muscle cells

The respective roles of protein kinase C (PKC) and of cytosolic free Ca2+ concentration ([Ca2+]i) in prostacyclin synthesis were investigated in aortic smooth muscle cells by using A23187 and phorbol 12-myristate 13-acetate (PMA) to bypass the hormonal receptor. Exposure of the cells to A23187 markedly increased prostacyclin production, which was not affected by the PKC inhibitor staurosporine or by PKC depletion after prolonged incubation (48 h) of cells with PMA. The increase in [Ca2+]i induced by A23187 did not affect membranous or cytosolic PKC activity in control and PMA-stimulated cells. Activation of PKC by PMA, a weak stimulant of prostacyclin production by itself, strongly potentiated A23187-induced prostacyclin production, as well as that induced by the calcium-mobilizing hormone arginine vasopressin (AVP). The potentiating effect persisted for 30 min after the removal of PMA. However, this "memory" effect was not due to sustained levels of membranous PKC activity but probably to the prolonged influence of PKC-induced phosphorylation(s). Taken together, our results suggest that, although an increase in [Ca2+]i is sufficient for inducing prostacyclin production in rat aortic smooth muscle cells, activation of PKC is necessary for AVP-induced prostacyclin production in this same tissue.

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Protein kinase C is involved in the cyclooxygenase-2 expression in rat aortic smooth muscle cells

The Japanese Journal of Pharmacology ◽

10.1016/s0021-5198(19)40978-5 ◽

1998 ◽

Vol 76 ◽

pp. 217

Author(s):

Kenji Manabe ◽

Hideya Sato ◽

Seiji Mizutari ◽

Tetsuhiro Hisayama ◽

Hideki Moritoki

Keyword(s):

Smooth Muscle ◽

Protein Kinase C ◽

Protein Kinase ◽

Smooth Muscle Cells ◽

Muscle Cells ◽

Cyclooxygenase 2 ◽

Aortic Smooth Muscle Cells ◽

Aortic Smooth Muscle ◽

Kinase C

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Mechanism of angiotensin II-induced arachidonic acid metabolite release in aortic smooth muscle cells: involvement of phospholipase D

Acta Endocrinologica ◽

10.1530/eje.0.1360207 ◽

1997 ◽

Vol 136 (2) ◽

pp. 207-212 ◽

Cited By ~ 6

Author(s):

Junji Shinoda ◽

Osamu Kozawa ◽

Atsushi Suzuki ◽

Yasuko Watanabe-Tomita ◽

Yutaka Oiso ◽

...

Keyword(s):

Arachidonic Acid ◽

Smooth Muscle ◽

Angiotensin Ii ◽

Smooth Muscle Cells ◽

Phospholipase D ◽

Muscle Cells ◽

Dependent Manner ◽

Ang Ii ◽

Aortic Smooth Muscle Cells ◽

Aortic Smooth Muscle

Abstract In a previous study, we have shown that angiotensin II (Ang II) activates phosphatidylcholinehydrolyzing phospholipase D due to Ang II-induced Ca2+ influx from extracellular space in subcultured rat aortic smooth muscle cells. In the present study, we have investigated the role of phospholipase D in Ang II-induced arachidonic acid (AA) metabolite release and prostacyclin synthesis in subcultured rat aortic smooth muscle cells. Ang II significantly stimulated AA metabolite release in a concentration-dependent manner in the range between 1 nmol/l and 0·1 μmol/l. d,l-Propranolol hydrochloride (propranolol), an inhibitor of phosphatidic acid phosphohydrolase, significantly inhibited the Ang II-induced release of AA metabolites. The Ang II-induced AA metabolite release was reduced by chelating extracellular Ca2+ with EGTA. Genistein, an inhibitor of protein tyrosine kinases, significantly suppressed the Ang II-induced AA metabolite release. 1,6-Bis-(cyclohexyloximinocarbonylamino)-hexane (RHC-80267), a potent and selective inhibitor of diacylglycerol lipase, significantly inhibited the Ang II-induced AA metabolite release. Both propranolol and RHC-80267 inhibited the Ang II-induced synthesis of 6-keto-prostaglandin F1α, a stable metabolite of prostacyclin. The synthesis was suppressed by genistein. These results strongly suggest that the AA metabolite release induced by Ang II is mediated, at least in part, through phosphatidylcholine hydrolysis by phospholipase D activation in aortic smooth muscle cells. European Journal of Endocrinology 136 207–212

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