Role of AT1 and AT2 receptors in regulation of MAPKs and MKP-1 by ANG II in adult cardiac myocytes

1998 ◽  
Vol 275 (3) ◽  
pp. H906-H916 ◽  
Author(s):  
Thomas A. Fischer ◽  
Krishna Singh ◽  
Donald S. O’Hara ◽  
David M. Kaye ◽  
Ralph A. Kelly
Keyword(s):  
Endothelial Cells ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Ventricular Myocytes ◽  
Mrna Levels ◽  
Ang Ii ◽  
Terminal Protein ◽  
Erk Activity ◽  
Angiotensin Type

ANG II has been implicated in the hypertrophic response in ventricular myocytes by acting at the angiotensin type 1 (AT1) receptor. However, the role of the angiotensin type 2 (AT2) receptor in the adult heart is not as clearly understood. In adult rat ventricular myocytes (ARVM) and cardiac microvascular endothelial cells (CMEC), we examined the role of ANG II signaling, via AT1 and AT2 receptors, on the activation of the extracellular signal-regulated protein kinases (ERKs) and on the expression of the mitogen-activated protein kinase (MAPK) phosphatase MKP-1. ANG II caused no detectable increase in ERK activity or in c- fos mRNA abundance in ARVM but increased ERK activity within 5 min in CMEC and increased c- fos mRNA levels. However, in the presence of the selective phosphoprotein phosphatase (PP-2A/PP-1) inhibitor okadaic acid (OA), a sustained increase in ERK activity, as well as in c- junNH2-terminal protein kinase activity, in ARVM was observed. ANG II increased MKP-1 mRNA levels within 15 min in ARVM and CMEC. In contrast to the response in endothelial cells, however, ANG II activation of MKP-1 in ARVM was mediated by AT2-receptor activation. Thus there is constitutive as well as inducible suppression of ERKs and c- junNH2-terminal protein kinases by MKP and PP-2A/PP-1 in the adult cardiac myocyte phenotype.

scholarly journals Novel protein kinase C-epsilon inhibits human CYP11B2 gene expression through ERK1/2 signalling pathway and JunB

2006 ◽  
Vol 36 (1) ◽  
pp. 51-64 ◽  
Author(s):  
Jean-Guy LeHoux ◽  
Andrée Lefebvre
Keyword(s):  
Protein Kinase ◽  
Mapk Pathway ◽  
Dominant Negative ◽  
Mrna Levels ◽  
Ang Ii ◽  
Protein Levels ◽  
Protein Kinase C Epsilon ◽  
Dependent Protein ◽  
H295r Cells

We previously reported that H295R cells co-express three diacylglycerol (DAG)-dependent protein kinase Cs (PKCs), namely conventional (c) PKCα and novel (n) PKCε and PKCϑ. The aim of the present work was to evaluate the implication of DAG-dependent PKCs in the activation of p44/42 MAP kinase (MAPK) by angiotensin II (Ang II) and to define the role of this pathway towards CYP11B2 regulation in H295R cells. The PKC inhibitor bisindolylmaleimide 1 (Bis) inhibited Ang II-induced p44/42 MAPK phosphorylation whereas the cPKC inhibitor Gö6976 failed to do so, thus ruling out the participation of PKCα. Ang II activated nPKCε and did not affect nPKCϑ, pinpointing PKCε as the mediator of Ang II in p44/42 MAPK activation. Overexpression of wild-type ERK1 and ERK2 significantly reduced basal as well as Ang II-stimulated human -2023CYP11B2-CAT activity; conversely, the two dominant negative mutants increased them. Overexpression of constitutively active (ca) PKCsuppressed Ang II-induced -2023CYP11B2-CAT activity. Infection of H295R cells with adenoviruses (Adv) expressing caPKCε activated endogenous MEK1/2 and p44/42 MAPK. Adv-caPKCε inhibited Ang II-stimulated aldosterone synthase mRNA levels and this action was reversed by the MEK1 inhibitor, PD98059. Also, Ang II increased JunB protein levels and this effect was inhibited by PD98059 and Bis. Adv-caPKCε enhanced JunB protein levels and PD98059 attenuated the increase. JunB overexpression abolished the Ang II-induced promoter activity within -138 bp of the 5′-flanking region of CYP11B2. Collectively, these results demonstrate that PKCε inhibits CYP11B2 transcription through the p44/42 MAPK pathway and JunB in H295R cells.

scholarly journals Ca2+ Microdomains, Calcineurin and the Regulation of Gene Transcription

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 875
Author(s):  
Gerald Thiel ◽  
Tobias Schmidt ◽  
Oliver G. Rössler
Keyword(s):  
Transcription Factors ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Gene Transcription ◽  
Intracellular Signaling ◽  
Second Messengers ◽  
Major Function ◽  
Surface Receptors ◽  
Dependent Protein

Ca2+ ions function as second messengers regulating many intracellular events, including neurotransmitter release, exocytosis, muscle contraction, metabolism and gene transcription. Cells of a multicellular organism express a variety of cell-surface receptors and channels that trigger an increase of the intracellular Ca2+ concentration upon stimulation. The elevated Ca2+ concentration is not uniformly distributed within the cytoplasm but is organized in subcellular microdomains with high and low concentrations of Ca2+ at different locations in the cell. Ca2+ ions are stored and released by intracellular organelles that change the concentration and distribution of Ca2+ ions. A major function of the rise in intracellular Ca2+ is the change of the genetic expression pattern of the cell via the activation of Ca2+-responsive transcription factors. It has been proposed that Ca2+-responsive transcription factors are differently affected by a rise in cytoplasmic versus nuclear Ca2+. Moreover, it has been suggested that the mode of entry determines whether an influx of Ca2+ leads to the stimulation of gene transcription. A rise in cytoplasmic Ca2+ induces an intracellular signaling cascade, involving the activation of the Ca2+/calmodulin-dependent protein phosphatase calcineurin and various protein kinases (protein kinase C, extracellular signal-regulated protein kinase, Ca2+/calmodulin-dependent protein kinases). In this review article, we discuss the concept of gene regulation via elevated Ca2+ concentration in the cytoplasm and the nucleus, the role of Ca2+ entry and the role of enzymes as signal transducers. We give particular emphasis to the regulation of gene transcription by calcineurin, linking protein dephosphorylation with Ca2+ signaling and gene expression.

α1-Adrenoceptor subtype activation increases proto-oncogene mRNA levels. Role of protein kinase C

1998 ◽  
Vol 342 (2-3) ◽  
pp. 311-317 ◽  
Author(s):  
J.Adolfo Garcı́a-Sáinz ◽  
Rocı́o Alcántara-Hernández ◽  
José Vázquez-Prado
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Mrna Levels ◽  
Kinase C

Abstract 261: Endothelial Cells Contribute to RAS Activation in Microvascular Smooth Muscle Cells

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Kayoko Miyata ◽  
Ryousuke Satou ◽  
L Gabriel Navar
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Mrna Expression ◽  
Culture Medium ◽  
Primary Cultures ◽  
Mrna Levels ◽  
Ang Ii ◽  
Relative Ratio ◽  
Renin Mrna ◽  
Afferent Arterioles

Introduction: We have demonstrated that Ang II augments angiotensinogen (AGT) expression in rat preglomerular vascular smooth muscle cells (VSMCs). However, it is unclear if endothelial cells (ECs) are involved in augmentation of AGT in renal afferent arterioles. Hypothesis: We assessed the hypothesis that the ECs respond to paracrine signals that Ang II contribute to AGT augmentation in VSMCs. Objective: We established primary cultures of preglomerular ECs and examined the effects of Ang II and/or culture medium from ECs on AGT expression in preglomerular VSMCs. Methods and Results: We established primary cultures of preglomerular ECs, isolated from afferent arterioles of Sprague-Dawley rats. The cells were identified as ECs by being positive for a marker, CD34 and endothelial NOS and negative for alpha-SMA (a marker for VSMCs) and P4H-b (a marker for Fibroblasts) by immnostaining. The expression levels of AGT mRNA and renin mRNA in preglomerular ECs were examined by real-time RT-PCR. Ang II (100 pmol/L) increased AGT mRNA levels (1.34 +/- 0.16, by 100 pmol/L, N=4) and Renin mRNA levels (6.16 +/- 0.96, by 100 nmol/L, N=4) in ECs. On the other hand, the same dose of Ang II suppressed Renin mRNA expression in isolated Juxtaglomerular cells (JGs). These results indicate that preglomerular ECs are respond to Ang II and exclude the possible contamination of JGs into ECs. 100 pmol/L of Ang II increased AGT mRNA expression levels (1.37 +/- 0.03, relative ratio, N=4) in preglomerular VSMCs and the culture medium of ECs without Ang II treatment also more increased AGT mRNA expression (1.62 +/- 0.13, relative ratio, N=4) in preglomerular VSMCs. The AGT mRNA expression augmentation was enhanced when preglomerular VSMCs were treated with culture medium of Ang II-treated preglomerular ECs (2.39 +/- 0.41, relative ratio, N=4). The synergistic effects of Ang II and preglomerular ECs were also observed in PAI-1 expression in preglomerular VSMCs. Conclusion: These data demonstrate that preglomerular ECs contribute to Ang II-upregulation of AGT in renal afferent arterioles leading to further Ang II augmentation, which leads to increases in inflammatory and sclerotic factors in preglomerular VSMCs.

scholarly journals Rate of calcium entry determines the rapid changes in protein kinase C activity in angiotensin II-stimulated adrenal glomerulosa cells

1994 ◽  
Vol 297 (3) ◽  
pp. 523-528 ◽  
Author(s):  
I Kojima ◽  
N Kawamura ◽  
H Shibata
Keyword(s):  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Specific Substrate ◽  
Ang Ii ◽  
Kinase C ◽  
Aldosterone Production ◽  
Glomerulosa Cells ◽  
Peptide Phosphorylation

The present study was conducted to monitor precisely the activity of protein kinase C (PKC) in adrenal glomerulosa cells stimulated by angiotensin II (ANG II). PKC activity in cells was monitored by measuring phosphorylation of a synthetic KRTLRR peptide, a specific substrate for PKC, immediately after the permeabilization of the cells with digitonin [Heasley and Johnson J. Biol. Chem. (1989) 264, 8646-8652]. Addition of 1 nM ANG II induced a gradual increase in KRTLRR peptide phosphorylation, which reached a peak at 30 min, and phosphorylation was sustained thereafter. When the action of ANG II was terminated by adding [Sar1,Ala8]ANG II, a competitive antagonist, both Ca2+ entry and KRTLRR phosphorylation ceased rapidly, whereas diacylglyercol (DAG) content was not changed significantly within 10 min. Similarly, when blockade of Ca2+ entry was achieved by decreasing extracellular Ca2+ to 1 microM or by adding 1 microM nitrendipine, KRTLRR peptide phosphorylation was decreased within 5 min. In addition, restoration of Ca2+ entry was accompanied by an immediate increase in KRTLRR peptide phosphorylation. Under the same condition, DAG content did not change significantly. We then examined the role of the PKC pathway in ANG II-induced aldosterone production. Ro 31-8220 inhibited ANG II-induced KRTLRR phosphorylation without affecting the activity of calmodulin-dependent protein kinase II. In the presence of Ro 31-8220, ANG II-mediated aldosterone production was decreased to approx. 50%. Likewise, intracellular administration of PKC19-36, a sequence corresponding to residues 19-36 of the regulatory domain of PKC known to inhibit PKC activity, attenuated ANG II-mediated activation of PKC and aldosterone output. These results indicate a critical role of Ca2+ entry in the regulation of PKC activity by ANG II.

Protein kinase Cε and the antiadrenergic action of adenosine in rat ventricular myocytes

2004 ◽  
Vol 287 (4) ◽  
pp. H1721-H1729 ◽  
Author(s):  
Koji Miyazaki ◽  
Satoshi Komatsu ◽  
Mitsuo Ikebe ◽  
Richard A. Fenton ◽  
James G. Dobson
Keyword(s):  
Electrical Stimulation ◽  
Protein Kinase ◽  
Ventricular Myocytes ◽  
Adrenergic Agonist ◽  
Inhibitory Peptide ◽  
Rat Ventricular Myocytes ◽  
Adult Rat ◽  
Tubular System ◽  
Stimulation Of

Adenosine-induced antiadrenergic effects in the heart are mediated by adenosine A1 receptors (A1R). The role of PKCε in the antiadrenergic action of adenosine was explored with adult rat ventricular myocytes in which PKCε was overexpressed. Myocytes were transfected with a pEGFP-N1 vector in the presence or absence of a PKCε construct and compared with normal myocytes. The extent of myocyte shortening elicited by electrical stimulation of quiescent normal and transfected myocytes was recorded with video imaging. PKCε was found localized primarily in transverse tubules. The A1R agonist chlorocyclopentyladenosine (CCPA) at 1 μM rendered an enhanced localization of PKCε in the t-tubular system. The β-adrenergic agonist isoproterenol (Iso; 0.4 μM) elicited a 29–36% increase in myocyte shortening in all three groups. Although CCPA significantly reduced the Iso-produced increase in shortening in all three groups, the reduction caused by CCPA was greatest with PKCε overexpression. The CCPA reduction of the Iso-elicited shortening was eliminated in the presence of a PKCε inhibitory peptide. These results suggest that the translocation of PKCε to the t-tubular system plays an important role in A1R-mediated antiadrenergic actions in the heart.

Cytochrome P-450 metabolites in endothelin-stimulated cardiac hormone secretion

2004 ◽  
Vol 286 (5) ◽  
pp. R888-R893 ◽  
Author(s):  
Sook Jeong Lee ◽  
Carol S. Landon ◽  
Stanley J. Nazian ◽  
John R. Dietz
Keyword(s):  
Protein Kinase ◽  
Inhibitory Action ◽  
Ventricular Myocytes ◽  
Hormone Secretion ◽  
Neonatal Rat ◽  
Kinase C ◽  
Neonatal Rat Ventricular Myocytes ◽  
Cytochrome P 450 ◽  
Kinase A

We examined the role of cytochrome P-450-arachidonate (CYP450-AA) metabolites in endothelin-1 (ET-1)-stimulated atrial natriuretic peptide (ANP) and pro-ANP-(1-30) secretion from the heart. 17-Octadecynoic acid (17-ODYA, 10-5 M) significantly inhibited ANP secretion stimulated by ET-1 (10-8 M) in the isolated perfused rat atria and inhibited pro-ANP-(1-30) secretion stimulated by ET-1 (10-8 M) or 20-hydroxyeicosatetraenoic acid in cultured neonatal rat ventricular myocytes (NRVM). In NRVM, 17-ODYA significantly ( P < 0.05) increased secretion of cAMP but had no significant effect on the secretion of cGMP from NRVM. Staurosporine, an inhibitor of protein kinase C, completely blocked the inhibitory action of 17-ODYA, whereas a protein kinase A inhibitor, H-89 (5 × 10-5 M), did not significantly attenuate the effects of 17-ODYA. The results show that the inhibitory action of 17-ODYA on ET-1-augmented ANP secretion is mediated through cAMP and suggest that CYP450-AA may play an important role in ET-1-induced cardiac hormone secretion.

Abstract P288: Systemic Administration of an Angiotensin Type-2 Receptor Agonist Decreases Renal Regulatory T Cells

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Ellen E Gillis ◽  
Jennifer C Sullivan
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Critical Role ◽  
High Dose ◽  
Ang Ii ◽  
Osmotic Minipump ◽  
Angiotensin Type 2 Receptor ◽  
Angiotensin Type

There is increasing evidence supporting a critical role of the immune system in the development of hypertension. Our lab has previously reported sex differences in the renal T cell profile in both Spontaneously Hypertensive Rats (SHR) and Angiotensin II (Ang II) models of hypertension, with females having more anti-inflammatory regulatory T cells (Tregs) than males. Ang II has a well-defined role in the activation of pro-inflammatory T cells in hypertension via the angiotensin type-1 receptor (AT1R). Less is known about the role of the angiotensin type-2 receptor (AT2R) in the regulation of immune cells, although the AT2R has been shown to be cardioprotective and AT2R expression is greater in females than males. Based on the potential anti-hypertensive role of AT2Rs, we hypothesized that administration of an AT2R agonist, Compound 21 (C21), would increase renal Tregs, and this increase would be greater in females due to greater AT2R expression. Male and female SHR (10 weeks of age, n=3-4) were implanted with telemetry units for continuous monitoring of mean arterial pressure (MAP). Following 10 days of recovery, baseline MAP was recorded for 5 days. Rats were then divided into the following treatment groups: surgical controls, low dose C21 (150 ng/kg/min, sc by osmotic minipump), high dose C21 (300 ng/kg/min, sc by osmotic minipump). Kidneys were harvested after 2 weeks of treatment and flow cytometry was performed on whole kidney homogenates. MAP was not altered by C21 treatment in males (137±4 vs 134±4 vs 134±4 mmHg; n.s.) or females (128±2 vs 136±5 vs 134±4 mmHg; n.s.). Interestingly, despite having no effect on MAP, there was a significant decrease in renal CD3 + CD4 + FoxP3 + Tregs in females following both low and high doses of C21 (data expressed as % CD3 + CD4 + cells: 6±0.6 vs 3±0.6 vs 3.5±1.3 %, respectively; p=0.02). Tregs decrease in males following the high dose of C21 only (data expressed as % CD3 + CD4 + cells: 3.3±0.3 vs 3.3±0.5 vs 1.7±0.7 %, respectively; p=0.05). Total CD3 + T cells, CD3 + CD4 + T cells, and Th17 cells were not altered by C21 treatment. In conclusion, AT2R activation suppresses renal Tregs, and females are more sensitive than males. These data suggest a novel role for AT2R regulation in the kidney in hypertension.

Sign in / Sign up

Export Citation Format

Share Document