Regulation of Na-K-ATPase gene expression by angiotensin II in vascular smooth muscle cells.
Na-K-adenosinetriphosphatase (Na-K-ATPase) activity profoundly influences vascular cell excitability, contractility, and volume regulation. We investigated the effect of angiotensin II on Na-K-ATPase gene expression in cultured rat vascular smooth muscle cells (VSMC). Na-K-ATPase alpha 1- and beta 1-isoform mRNAs, but not alpha 2- and alpha 3-isoform mRNAs, were expressed in cultured rat VSMC. Angiotensin II (1 microgram/ml) caused a threefold increase in alpha 1-mRNA accumulation and a fourfold increase in beta 1-mRNA accumulation; the peak increases for both alpha 1- and beta 1-mRNA were observed at 6 h. Angiotensin II induced alpha 1- and beta 1-mRNA expression in a dose-dependent manner. Pretreatment of VSMC with cycloheximide (20 micrograms/ml) or actinomycin D (5 micrograms/ml) completely inhibited angiotensin II-induced alpha 1-mRNA accumulation. Even after protein kinase C (PKC) activity was functionally depleted by treating VSMC with phorbol 12-myristate 13-acetate (10(-6) M) for 24 h, angiotensin II increased alpha 1-mRNA accumulation. The angiotensin II-induced increase in alpha 1-mRNA accumulation was associated with an increase in alpha 1-subunit protein accumulation. These results indicate that angiotensin II stimulates Na-K-ATPase alpha 1- and beta 1-isoform gene expression in VSMC and that the effect is mediated not via activation of PKC but needs synthesis of intermediate regulatory protein(s).
Ikeda
U
U
Department of Cardiology, Jichi Medical School, Tochigi, Japan.
Takahashi
M
M
Okada
K
K
Saito
T
T
Shimada
K
K
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000201:enzymology*; D015152:Blotting, Northern; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction; D004797:Enzyme-Linked Immunosorbent Assay; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D007527:Isoenzymes / Q000032:analysis / Q000096:biosynthesis / Q000302:isolation & purification; D007700:Kinetics; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis / Q000096:biosynthesis* / Q000302:isolation & purification; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007527:Isoenzymes; D012333:RNA, Messenger; D000804:Angiotensin II; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D000254:Sodium-Potassium-Exchanging ATPase; D013755:Tetradecanoylphorbol Acetate