Induction of Angiotensinogen mRNA in Hepatocytes by Angiotensin II and Glucocorticoids

Klett, C. James; Hellmann, W.; Suzuki, Fujio; Nakanishi, Shigetada; Ohkubo, Hiroaki; Ganten, Detlev; Hackenthal, E.

doi:10.1080/07300077.1988.11878797

Cited by 18 publications

(13 citation statements)

References 20 publications

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“…Angiotensin II might contribute to the feedback regulation of renal angiotensinogen mRNA in heart failure. Local angiotensin II concentrations might be increased in this syndrome, and previous studies have shown that angiotensin II can stimulate hepatic angiotensinogen synthesis and expression (42,43). We have demonstrated recently that renal angiotensinogen expression can be increased by high plasma levels of angiotensin II (achieved by intravenous infusion) (44).…”

Section: Discussionmentioning

confidence: 99%

Evidence for tissue-specific activation of renal angiotensinogen mRNA expression in chronic stable experimental heart failure.

Schunkert¹,

Ingelfinger²,

Hirsch³

et al. 1992

J. Clin. Invest.

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The intrarenal renin-angiotension system (RAS) may contribute to the pathophysiology of heart failure by the generation of angiotensin II at local sites within the kidneys. Angiotensin II may directly influence renal hemodynamics, glomerular contractility, and tubular sodium reabsorption, thereby promoting sodium and fluid retention in this syndrome. In the present study, we examined components of the circulating RAS as well as the intrarenal expressions of renin and angiotensinogen mRNA in rats with stable compensated heart failure (HF) 12 wk after experimental myocardial infarction. Renal angiotensinogen mRNA level in vehicle-treated HF rats increased 47%, as compared with sham control rats (P = 0.001). The increase in angiotensinogen mRNA levels was more pronounced in animals with medium (46%, P < 0.05) and large (66%, P < 0.05) infarcts than in those with small infarcts (31%, P = NS). There were no differences in liver angiotensinogen mRNA, circulating angiotensinogen, angiotensin II, plasma renin concentration (PRC), kidney renin content (KRC), and renal renin mRNA level between sham and HFv. In addition, in a separate group of rats with heart failure, we demonstrated that renal angiotensin II concentration increased twofold (P < 0.05) as compared with that of age-matched sham operated controls. A parallel group of heart failure rats (HFe, n = 11) was treated with enalapril (25 mg/kg per d) in drinking water for 6 wk before these measurements. Blood pressure decreased significantly during treatment (91 vs. 103 mm Hg, P < 0.05). Enalapril treatment in HF rats increased renin mRNA level (2.5-fold, P < 0.005), KRC (5.6-fold, P = 0.005), and PRC (15.5-fold, P < 0.005). The increase in renal angiotensinogen mRNA level observed in HFv rats was markedly attenuated in enalapril treated HF rats (P < 0.001), suggesting a positive feedback of angiotensin II on renal angiotensinogen synthesis. These findings demonstrate an activation of intrarenal RAS, but no changes in the circulating counterpart in this model of experimental heart failure, and

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Section: Discussionmentioning

confidence: 99%

Evidence for tissue-specific activation of renal angiotensinogen mRNA expression in chronic stable experimental heart failure.

Schunkert¹,

Ingelfinger²,

Hirsch³

et al. 1992

J. Clin. Invest.

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“…43,44 Isoproterenol-induced accumulation of angiotensinogen mRNA in mouse hepatoma cells is mediated by cAMP response element in the promoter of the angiotensinogen gene. 45 Rat VSMC have previously been shown to produce angiotensinogen.…”

Section: Discussionmentioning

confidence: 99%

Production of Angiotensin II by Homogeneous Cultures of Vascular Smooth Muscle Cells From Spontaneously Hypertensive Rats

Fukuda

Satoh

et al. 1999

ATVB

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Abstract-Production of angiotensin II (Ang II) in spontaneously hypertensive rats (SHR)-derived vascular smooth muscle cells (VSMC) has now been investigated. A nonpeptide antagonist (CV-11974) of Ang II type 1 receptors inhibited basal DNA synthesis in VSMC from SHR, but it had no effect on cells from Wistar-Kyoto (WKY) rats. Ang II-like immunoreactivity, determined by radioimmunoassay after HPLC, was readily detected in conditioned medium and extracts of SHR-derived VSMC, whereas it was virtually undetectable in VSMC from WKY rats. Isoproterenol increased the amount of Ang II-like immunoreactivity in conditioned medium and extracts of SHR-derived VSMC, whereas the angiotensin-converting enzyme inhibitor delapril significantly reduced the amount of Ang II-like immunoreactivity in conditioned medium and extracts of these cells. Reverse transcription-polymerase chain reaction analysis revealed that the abundance of mRNAs encoding angiotensinogen, cathepsin D, and angiotensin-converting enzyme was greater in VSMC from SHR than in cells from WKY rats. The abundance of cathepsin D protein by Western blotting was greater in VSMC from SHR than in cells from WKY rats. Ang I-generating and acid protease activities were detected in VSMC from SHR, but not in cells from WKY rats. These results suggest that SHR-derived VSMC generate Ang II with increases in angiotensinogen, cathepsin D, and angiotensin-converting enzyme, which contribute to the basal growth. Production of Ang II by homogeneous cultures of VSMC is considered as a new mechanism of hypertensive vascular disease.

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“…Angiotensin II increases levels of mRNAs for the EGF receptor in WB cells (18), angiotensinogen in hepatocytes (2,45), and catecholamine-synthesizing enzymes in adrenal meduilary cells (63). Both angiotensin II (26) and [Arg8]vasopressin (25) stimulate hypertrophy of vascular smooth muscle cells.…”

Section: Discussionmentioning

confidence: 99%

Angiotensin II stimulates protein-tyrosine phosphorylation in a calcium-dependent manner.

Huckle¹,

Prokop²,

Dy³

et al. 1990

Mol. Cell. Biol.

121

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Cellular responses to epidermal growth factor (EGF) are dependent on the tyrosine-specific protein kinase activity of the cell-surface EGF receptor. Previous studies using WB rat liver epithelial cells have detected at least 10 proteins whose phosphotyrosine (P-Tyr) content is increased by EGF. In this study, we have examined alternate modes of activating tyrosine phosphorylation. Treatment of WB cells with hormones linked to Ca2+ mobilization and protein kinase C (PKC) activation, including angiotensin II, [Arg8]vasopressin, or epinephrine, stimulated rapid (<15-s) and transient increases in the P-Tyr content of several proteins (p120/125, p75/78, and p66). These proteins, detected by anti-P-Tyr immunoblotting, were similar in molecular weight to a subset of EGF-sensitive P-Tyr-containing proteins (P-Tyr-proteins all P-Tyr-proteins in response to angiotensin II, thapsigargin, or ionophores, as well as two EGF-stimulated P-Tyr-proteins. The majority of EGF-stimulated P-Tyr-proteins were not affected by BAPTA. These studies indicate that angiotensin II can alter protein-tyrosine phosphorylation in a manner that is secondary to, and apparently dependent on, Ca2+ mobilization. Thus, ligands such as EGF and angiotensin II, which act through distinct types of receptors, may activate secondary pathways involving tyrosine phosphorylation. These results also raise the possibility that certain growth-promoting effects of Ca2+-mobilizing agents such as angiotensin H may be mediated via tyrosine phosphorylation.Reversible phosphorylation of proteins is a major mechanism by which metabolic processes are regulated. Phosphorylation on serine and threonine residues, which together account for >99% of total cellular protein phosphate, are recognized as key elements in the regulation of such diverse pathways as glycogen metabolism, protein biosynthesis, and cell surface receptor signaling (19). Phosphorylation on tyrosine residues, which accounts for <0.5% of proteinbound phosphate (12), has been linked broadly with the control of cell proliferation. Receptors for several growth factors, including epidermal growth factor (EGF) and platelet-derived growth factor, contain ligand-activated, tyrosinespecific protein kinase domains essential for biological activity (76, 78). Similarly, the protein products of several oncogenes (e.g., src and ab) exhibit tyrosine kinase activities essential for oncogenic transformation (36,41).The identities of relevant substrates for tyrosine kinases remain largely obscure because of the technical challenge of monitoring transient tyrosine phosphorylation events against high backgrounds of serine/threonine phosphorylation and because of the complex and temporally protracted nature of mitogenesis. Nevertheless, several potential substrates for tyrosine kinases in intact cells have been identified, using combinations of 32p labeling, electrophoresis, phosphoami-* Corresponding author. no acid analysis, and immunoprecipitation and immunoblotting with antiphosphotyrosine (anti-P-Tyr) antibodies. One gro...

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Induction of Angiotensinogen mRNA in Hepatocytes by Angiotensin II and Glucocorticoids

Cited by 18 publications

References 20 publications

Evidence for tissue-specific activation of renal angiotensinogen mRNA expression in chronic stable experimental heart failure.

Evidence for tissue-specific activation of renal angiotensinogen mRNA expression in chronic stable experimental heart failure.

Production of Angiotensin II by Homogeneous Cultures of Vascular Smooth Muscle Cells From Spontaneously Hypertensive Rats

Angiotensin II stimulates protein-tyrosine phosphorylation in a calcium-dependent manner.

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