Protein kinase C and protein kinase A regulate the expression of angiotensin II receptor mRNA in smooth muscle cells.
Using reverse transcription polymerase chain reaction and fura-2 microfluorometry of intracellular Ca2+ concentrations, we investigated the effects of angiotensin II and cyclic AMP on the expression of angiotensin II type 1 receptor mRNA and the relationship between angiotensin II receptor mRNA level and physiological responsiveness in rat aortic smooth muscle cells in primary culture. Angiotensin II (1 microM) induced a time- and dose-dependent transient decrease in the level of angiotensin II receptor mRNA. The maximal decrease (50 +/- 13% of control) occurred at 6 h, followed by a gradual return to the control level within 24 h. H-7 (30 microM), a relatively specific protein kinase C inhibitor, inhibited decrease in the expression of angiotensin II receptor mRNA induced by 6 h angiotensin II treatment, while 6 h stimulation by 0.3 microM phorbol 12-myristate 13-acetate also induced a decrease (35 +/- 8% of control) in the expression of angiotensin II receptor mRNA. An increase in cellular cyclic AMP induced by 10 microM forskolin plus 10 microM 3-isobutyl-1-methyl-xanthine, decreased the angiotensin II receptor mRNA level to 50 +/- 13% of the control at 6 h and increased it to 219 +/- 39% of the control at 48 h of treatment. Angiotensin II-induced decrease and cyclic AMP-induced increase in the expression of angiotensin II receptor mRNA were accompanied by a reduction and enhancement in [Ca2+]i transients induced by angiotensin II, respectively. In contrast with angiotensin II receptor mRNA level (102 +/- 8% of control), the [Ca2+]i transients were markedly decreased in angiotensin II plus H-7 treated cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Chen
X
X
Division of Molecular Cardiology, Faculty of Medicine, Kyushu University, Higashi-ku, Japan.
Nishimura
J
J
Hasna
J
J
Kobayashi
S
S
Shikasho
T
T
Kanaide
H
H
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D015536:Down-Regulation / Q000187:drug effects; D016257:Fura-2; D008297:Male; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011493:Protein Kinase C / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D011945:Receptors, Angiotensin / Q000096:biosynthesis*
D012333:RNA, Messenger; D011945:Receptors, Angiotensin; D000804:Angiotensin II; D005576:Colforsin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D015056:1-Methyl-3-isobutylxanthine; D016257:Fura-2