c-Jun NH2-terminal kinase mediation of angiotensin II-induced proliferation of human mesangial cells

2005 ◽  
Vol 288 (6) ◽  
pp. F1118-F1124 ◽  
Author(s):  
Aihua Zhang ◽  
Guixia Ding ◽  
Songming Huang ◽  
Yuanjun Wu ◽  
Xiaoqing Pan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Angiotensin Ii ◽  
Map Kinases ◽  
Mesangial Cells ◽  
Cell Number ◽  
Renal Diseases ◽  
Steady Increase ◽  
Dependent Manner ◽  
Ang Ii ◽  
Human Mesangial Cells

Angiotensin II (ANG II) has been shown to activate c-Jun NH2-terminal kinase (JNK) in cultured mesangial cells, but the functional implication of this phenomenon remains to be determined, largely due to the lack of an effective approach to block JNK. Therefore, the present study was carried out to examine whether JNK is involved in ANG II-induced cell proliferation in cultured human mesangial cells (HMCs) with the use of a newly developed JNK-selective blocker, SP-600125. Within minutes, treatment with 100 nM ANG II activated all three members of MAP kinase family, including extracellular signal-regulated protein kinase (Erk) 1/2, JNK, and p38 in cultured HMCs, as assessed by immunoblotting detection of phosphorylation of MAP kinases. ANG II-dependent activation of JNK was further confirmed by detection of increased phosphorylation and transcription activity of c-Jun after the ANG II treatment. SP-600125 ranging from 5 to 10 μM almost completely abolished the activation of JNK by ANG II without affecting the activities of Erk1/2 and p38. After treatment with 100 ng ANG II, there was a steady increase in [3H]thymidine incorporation that was blocked by SP-60025 in a dose- and time-dependent manner. Similarly, SP-600125 dose dependently reduced the ANG II-induced increase in cell number. The antiproliferative effect of SP-60025 was further determined by cell-cycle analysis with flow cytometry. Twenty-four hours after ANG II treatment, 50% of the quiescent HMCs (G0/G1) progressed into the S phase, and the cell cycle progression was almost completely prevented in the presence of SP-60025. Our data suggest that JNK mediates the proliferative effect of ANG II in cultured HMCs and thus represents a novel therapeutic target for treatment of chronic renal diseases.

scholarly journals Carvedilol Inhibits Angiotensin II-Induced Proliferation and Contraction in Hepatic Stellate Cells through the RhoA/Rho-Kinase Pathway

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Ying Wu ◽  
Zhen Li ◽  
Sining Wang ◽  
Aiyuan Xiu ◽  
Chunqing Zhang
Keyword(s):  
Cell Cycle ◽  
Angiotensin Ii ◽  
Liver Fibrosis ◽  
Cell Cycle Progression ◽  
Rho Kinase ◽  
Cell Counting ◽  
Type I ◽  
Dependent Manner ◽  
Ang Ii ◽  
Cycle Progression

Aim. Carvedilol is a nonselective beta-blocker used to reduce portal hypertension. This study investigated the effects and potential mechanisms of carvedilol in angiotensin II- (Ang II-) induced hepatic stellate cell (HSC) proliferation and contraction. Methods. The effect of carvedilol on HSC proliferation was measured by Cell Counting Kit-8 (CCK-8). Cell cycle progression and apoptosis in HSCs were determined by flow cytometry. A collagen gel assay was used to confirm HSC contraction. The extent of liver fibrosis in mice was evaluated by hematoxylin-eosin (H&E) and Sirius Red staining. Western blot analyses were performed to detect the expression of collagen I, collagen III, α-smooth muscle actin (α-SMA), Ang II type I receptor (AT1R), RhoA, Rho-kinase 2 (ROCK2), and others. Results. The results showed that carvedilol inhibited HSC proliferation and arrested the cell cycle at the G0/G1 phase in a dose-dependent manner. Carvedilol also modulated Bcl-2 family proteins and increased apoptosis in Ang II-treated HSCs. Furthermore, carvedilol inhibited HSC contraction induced by Ang II, an effect that was associated with AT1R-mediated RhoA/ROCK2 pathway interference. In addition, carvedilol reduced α-SMA expression and collagen deposition and attenuated liver fibrosis in carbon tetrachloride (CCl4)-treated mice. The in vivo data further confirmed that carvedilol inhibited the expression of angiotensin-converting enzyme (ACE), AT1R, RhoA, and ROCK2. Conclusions. The results indicated that carvedilol dose-dependently inhibited Ang II-induced HSC proliferation by impeding cell cycle progression, thus alleviating hepatic fibrosis. Furthermore, carvedilol could inhibit Ang II-induced HSC contraction by interfering with the AT1R-mediated RhoA/ROCK2 pathway.

Molecular mechanism of ADP-ribosyl cyclase activation in angiotensin II signaling in murine mesangial cells

2008 ◽  
Vol 294 (4) ◽  
pp. F982-F989 ◽  
Author(s):  
Seon-Young Kim ◽  
Rukhsana Gul ◽  
So-Young Rah ◽  
Suhn Hee Kim ◽  
Sung Kwang Park ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Protein Tyrosine Kinase ◽  
Nuclear Translocation ◽  
Mesangial Cells ◽  
Dependent Manner ◽  
Ang Ii ◽  
Akt Phosphorylation ◽  
Cyclase Activation ◽  
Adp Ribosyl Cyclase ◽  
Phosphoinositide 3 Kinase

ADP-ribosyl cyclase (ADPR-cyclase) produces a Ca2+-mobilizing second messenger cyclic ADP-ribose (cADPR) from NAD+. In this study, we investigated the molecular basis of ADPR-cyclase activation and the following cellular events in angiotensin II (ANG II) signaling in mouse mesangial cells (MMCs). Treatment of MMCs with ANG II induced an increase in intracellular Ca2+ concentrations through a transient Ca2+ release via an inositol 1,4,5-trisphosphate receptor and a sustained Ca2+ influx via L-type Ca2+ channels. The sustained Ca2+ signal, but not the transient Ca2+ signal, was blocked by a cADPR antagonistic analog, 8-bromo-cADPR (8-Br-cADPR), and an ADPR-cyclase inhibitor, 4,4′-dihydroxyazobenzene (DHAB). In support of the results, ANG II stimulated cADPR production in a time-dependent manner, and DHAB inhibited ANG II-induced cADPR production. Application of pharmacological inhibitors revealed that activation of ADPR-cyclase by ANG II involved ANG II type 1 receptor, phosphoinositide 3-kinase, protein tyrosine kinase, and phospolipase C-γ1. Moreover, DHAB as well as 8-Br-cADPR abrogated ANG II-mediated Akt phosphorylation, nuclear translocation of nuclear factor of activated T cell, and uptake of [3H]thymidine and [3H]leucine in MMCs. These results demonstrate that ADPR-cyclase in MMCs plays a pivotal role in ANG II signaling for cell proliferation and protein synthesis.

Involvement of endogenous nitric oxide in angiotensin II-induced activation of vascular mitogen-activated protein kinases

2007 ◽  
Vol 293 (4) ◽  
pp. H2403-H2408 ◽  
Author(s):  
Guo-Xing Zhang ◽  
Yukiko Nagai ◽  
Toshitaka Nakagawa ◽  
Hiroshi Miyanaka ◽  
Yoshihide Fujisawa ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Map Kinase ◽  
Map Kinases ◽  
No Synthase ◽  
Dependent Manner ◽  
Ang Ii ◽  
No Donor ◽  
Mitogen Activated Protein ◽  
Kinase Phosphorylation

Angiotensin II (ANG II) is a powerful activator of mitogen-activated protein (MAP) kinase cascades in cardiovascular tissues through a redox-sensitive mechanism. Nitric oxide (NO) is considered to antagonize the vasoconstrictive and proarteriosclerotic actions of ANG II. However, the role of endogenous NO in ANG II-induced redox-sensitive signal transduction is not yet clear. In this study using catheterized, conscious rats, we found that acute intravenous administration of NG-nitro-l-arginine methyl ester (l-NAME; 5 mg/kg) enhanced phosphorylation of aortic MAP kinases extracellular signal regulated kinase (ERK) 1/2 and p38, which were suppressed only partially by a superoxide dismutase mimetic (Tempol), whereas ANG II-induced MAP kinase phosphorylation was markedly suppressed by Tempol. FK409, a NO donor, had little effect on vascular MAP kinase phosphorylation. On the other hand, acute exposure to a vasoconstrictor dose of ANG II (200 ng·kg−1·min−1 iv) failed to enhance phosphorylation of aortic MAP kinases in the chronically l-NAME-treated rats, whereas the vasoconstrictor effect of ANG II was not affected by l-NAME treatment. Furthermore, three different inhibitors of NO synthase suppressed, in a dose-dependent manner, ANG II-induced MAP kinase phosphorylation in rat vascular smooth muscle cells, which was closely linked to superoxide generation in cells. These results indicate the involvement of endogenous NO synthase in ANG II-induced signaling pathways, leading to activation of MAP kinase, and that NO may have dual effects on the vascular MAP kinase activation associated with redox sensitivity.

scholarly journals Angiotensin II type 1 receptor blocker attenuates the activation of ERK and NADPH oxidase by mechanical strain in mesangial cells in the absence of angiotensin II

2009 ◽  
Vol 296 (5) ◽  
pp. F1052-F1060 ◽  
Author(s):  
Junichi Yatabe ◽  
Hironobu Sanada ◽  
Midori Sasaki Yatabe ◽  
Shigeatsu Hashimoto ◽  
Minoru Yoneda ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Nadph Oxidase ◽  
Mesangial Cells ◽  
Mechanical Strain ◽  
Dependent Manner ◽  
Ang Ii ◽  
Erk Phosphorylation ◽  
Extracellular Signal

It has been reported that mechanical strain activates extracellular signal-regulated protein kinases (ERK) without the involvement of angiotensin II (Ang II) in cardiomyocytes. We examined the effects of mechanical strain on ERK phosphorylation levels in the absence of Ang II using rat mesangial cells. The ratio of phosphorylated ERK (p-ERK) to total ERK expression was increased by cyclic mechanical strain in a time- and elongation strength-dependent manner. With olmesartan [Ang II type 1 receptor (AT1R) antagonist] pretreatment, p-ERK plateau levels decreased in a dose-dependent manner (EC50 = 1.3 × 10−8 M, maximal inhibition 50.6 ± 11.0% at 10−5 M); a similar effect was observed with RNA interference against Ang II type 1A receptor (AT1AR) and Tempol, a superoxide dismutase mimetic. In addition to the inhibition of p-ERK levels, olmesartan blocked the increase in cell surface and phosphorylated p47phox induced by mechanical strain and also lowered the mRNA expression levels of NADPH oxidase subunits. These results demonstrate that mechanical strain stimulates AT1R to phosphorylate ERK in mesangial cells in the absence of Ang II. This mechanotransduction mechanism is involved in the oxidative stress caused by NADPH oxidase and is blocked by olmesartan. The inverse agonistic activity of this AT1R blocker may be useful for the prevention of mesangial proliferation and renal damage caused by mechanical strain/oxidative stress regardless of circulating or tissue Ang II levels.

scholarly journals AT1 receptor-mediated uptake of angiotensin II and NHE-3 expression in proximal tubule cells through a microtubule-dependent endocytic pathway

2009 ◽  
Vol 297 (5) ◽  
pp. F1342-F1352 ◽  
Author(s):  
Xiao C. Li ◽  
Ulrich Hopfer ◽  
Jia L. Zhuo
Keyword(s):  
Angiotensin Ii ◽  
Proximal Tubule ◽  
Map Kinases ◽  
Endocytic Pathway ◽  
Dependent Manner ◽  
Ang Ii ◽  
Cellular Mechanisms ◽  
Proximal Tubule Cells ◽  
Associated Proteins ◽  
Transferrin Uptake

Angiotensin II (ANG II) is taken up by proximal tubule (PT) cells via AT1 (AT1a) receptor-mediated endocytosis, but the underlying cellular mechanisms remain poorly understood. The present study tested the hypothesis that the microtubule- rather than the clathrin-dependent endocytic pathway regulates AT1-mediated uptake of ANG II and ANG II-induced sodium and hydrogen exchanger-3 (NHE-3) expression in PT cells. The expression of AT1 receptors, clathrin light (LC) and heavy chain (HC) proteins, and type 1 microtubule-associated proteins (MAPs; MAP-1A and MAP-1B) in PT cells were knocked down by their respective small interfering (si) RNAs before AT1-mediated FITC-ANG II uptake and ANG II-induced NHE-3 expression were studied. AT1 siRNAs inhibited AT1 expression and blocked ANG II-induced NHE-3 expression in PT cells, as expected ( P < 0.01). Clathrin LC or HC siRNAs knocked down their respective proteins by ∼90% with a peak response at 24 h, and blocked the clathrin-dependent uptake of Alexa Fluor 594-transferrin ( P < 0.01). However, neither LC nor HC siRNAs inhibited AT1-mediated uptake of FITC-ANG II or affected ANG II-induced NHE-3 expression. MAP-1A or MAP-1B siRNAs markedly knocked down MAP-1A or MAP-1B proteins in a time-dependent manner with peak inhibitions at 48 h (>76.8%, P < 0.01). MAP protein knockdown resulted in ∼52% decreases in AT1-mediated FITC-ANG II uptake and ∼66% decreases in ANG II-induced NHE-3 expression ( P < 0.01). These effects were associated with threefold decreases in ANG II-induced MAP kinases ERK 1/2 activation ( P < 0.01), but not with altered AT1 expression or clathrin-dependent transferrin uptake. Both losartan and AT1a receptor deletion in mouse PT cells completely abolished the effects of MAP-1A knockdown on ANG II-induced NHE-3 expression and activation of MAP kinases ERK1/2. Our findings suggest that the alternative microtubule-dependent endocytic pathway, rather than the canonical clathrin-dependent pathway, plays an important role in AT1 (AT1a)-mediated uptake of extracellular ANG II and ANG II-induced NHE-3 expression in PT cells.

Endothelin modulates angiotensin II-induced mitogenesis of human mesangial cells

1993 ◽  
Vol 264 (6) ◽  
pp. F937-F942 ◽  
Author(s):  
G. L. Bakris ◽  
R. N. Re
Keyword(s):  
Angiotensin Ii ◽  
Mesangial Cell ◽  
Thymidine Incorporation ◽  
Mesangial Cells ◽  
Culture Conditions ◽  
Ang Ii ◽  
Mitogenic Effect ◽  
Mitogenic Response ◽  
Human Mesangial Cells ◽  
Cell Counts

Angiotensin II (ANG II) elicits either a hypertrophic or hyperplastic response depending on culture conditions. Human mesangial cell (HMC)-generated endothelin (ET) plays a role in mediating the hyperplastic effects of arginine vasopressin. The interaction between ANG II and ET is not described in HMC. The present study evaluates the possible effect of ANG II on HMC production of ET, its relationship to mitogenesis, and the effect of insulin. ANG II (10(-8) M) increased [3H]thymidine incorporation in proliferative HMC at 48 h (13 +/- 1 vs. 24 +/- 1 x 10(3) counts.min-1.well-1, for control vs. ANG II; P < 0.05). Cell counts showed parallel increases [12 +/- 1 (control) vs. 18 +/- 1 x 10(3) counts/well; P < 0.05]. This mitogenic effect was attenuated by a monoclonal antibody to ET-1 or the ANG II-receptor antagonist, DuP 753. Insulin potentiated the mitogenic response of ANG II through increases in HMC ET production (69 +/- 7 vs. 189 +/- 13 pg/ml, for insulin alone vs. insulin+ANG II; P < 0.05). This study supports the concept that ANG II may act as a mitogen under certain culture conditions and its effect is, in part, mediated through ET.

Ca2+/calmodulin-dependent and cAMP-dependent kinases in induction of c-fos in human mesangial cells

2002 ◽  
Vol 283 (5) ◽  
pp. F888-F894 ◽  
Author(s):  
Hong Zeng ◽  
Ying Liu ◽  
Douglas M. Templeton
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Mesangial Cells ◽  
Camp Response Element Binding ◽  
Renal Diseases ◽  
Serum Starvation ◽  
Early Event ◽  
Rapid Decline ◽  
Subsequent Increase ◽  
Human Mesangial Cells

Mesangial cell proliferation is an early event in several progressive renal diseases. When mesangial cells in culture are rendered quiescent by serum starvation and subsequently stimulated to proliferate, induction of c- fos is an early indicator of entry into the cell cycle. Several heparin-sensitive signals transduce these events. We have examined the potential roles of CaMK and PKA. Selective stimulation of CaMK with Ca2+ ionophores and of PKA with forskolin or dibutyryl cAMP both result in induction of c- fos mRNA. CaMK but not PKA signaling is suppressed by low concentrations of heparin. Cross talk between the pathways has been demonstrated in some cells, with evidence of CaMK phosphorylating cAMP response element binding protein (CREB) at an inhibitory site and PKA suppressing CaMK-dependent signaling. However, in the present study, both pathways phosphorylated CREB on Ser133 and induced c- fosin an additive manner. Serum, ionomycin, and forskolin all caused a rapid decline in cyclin D1 levels, but only serum effected a subsequent increase, indicative of cell cycle progression. We conclude that, in human mesangial cells, CaMK and PKA can both contribute to cell cycle entry, and, although induction of c- fos by CaMK requires active PKA, neither pathway antagonizes or synergizes c- fosinduction by the other.

Differential regulation of angiotensin II and losartan binding sites in glomeruli and mesangial cells

1994 ◽  
Vol 266 (3) ◽  
pp. F384-F393 ◽  
Author(s):  
D. Chansel ◽  
T. Bizet ◽  
S. Vandermeersch ◽  
P. Pham ◽  
B. Levy ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Binding Sites ◽  
Mesangial Cells ◽  
Present Report ◽  
Mrna Levels ◽  
Ang Ii ◽  
Experimental Conditions ◽  
Human Mesangial Cells

The aim of the present report was to examine the effect of several agents on angiotensin II (ANG II) and losartan receptors using 125I-[Sar1,Ala8]ANG II and [3H]losartan as radiolabeled ligand, respectively. ANG II receptors were downregulated in glomeruli from rats infused with ANG II during 3 wk or rats receiving losartan orally during 1 wk. The number of sites (Bmax) was reduced, but the dissociation constant (Kd) value was unchanged. Losartan receptors were downregulated in glomeruli from rats receiving losartan, but remained unchanged in glomeruli from rats infused with ANG II. Since in vivo administration of losartan results in increase of plasma ANG II and formation of metabolites, in vitro studies using human mesangial cells were performed to better analyze the present findings. Treatment of mesangial cells during 4 days by ANG II, losartan, or its metabolite, EXP-3174, also produced downregulation of 125I-[Sar1,Ala8]ANG II binding sites with a decreased Bmax and unchanged Kd value. Only treatment of mesangial cells by ANG II or EXP-3174 produced downregulation of [3H]losartan binding sites. In contrast, exposure of these cells to losartan resulted in upregulation of [3H]losartan binding sites. Under all conditions, only Bmax was modified. Whereas internalization of [3H]losartan in mesangial cells was negligible under all experimental conditions, there was an increase of the percentage of internalized 125I-[Sar1,Ala8]ANG II after exposure of the cells to ANG II or AT1 antagonists. No change was observed in mesangial cell AT1 receptor mRNA levels. This study demonstrates that 1) AT1 mRNA is expressed in human mesangial cells; 2) the characteristics of 125I-[Sar1,Ala8]ANG II and [3H]losartan binding sites in rat glomeruli and human mesangial cells are different, with Kd and Bmax values greater in both preparations when [3H]losartan was utilized; 3) both types of binding sites obey different regulations, and the effects of losartan in vivo are due in part to the associated increase in plasma ANG II levels and the transformation of the drug into its metabolite, EXP-3174; 4) downregulation of AT1 receptors does not depend on changes in mRNA expression but is associated with increased relative internalization.

scholarly journals Melanoma Differentiation-Associated Gene 5 Regulates the Expression of a Chemokine CXCL10 in Human Mesangial Cells: Implications for Chronic Inflammatory Renal Diseases

2012 ◽  
Vol 228 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Tadaatsu Imaizumi ◽  
Tomomi Aizawa-Yashiro ◽  
Kazushi Tsuruga ◽  
Hiroshi Tanaka ◽  
Tomoh Matsumiya ◽  
...  
Keyword(s):  
Mesangial Cells ◽  
Renal Diseases ◽  
Human Mesangial Cells

Modulation of Ca2+ transients in neonatal and adult rat cardiomyocytes by angiotensin II and endothelin-1

1996 ◽  
Vol 270 (3) ◽  
pp. H857-H868 ◽  
Author(s):  
R. M. Touyz ◽  
J. Fareh ◽  
G. Thibault ◽  
B. Tolloczko ◽  
R. Lariviere ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Receptor Agonist ◽  
Dependent Manner ◽  
Induced Responses ◽  
Ang Ii ◽  
Binding Studies ◽  
Vasoactive Peptides ◽  
Adult Cardiomyocytes ◽  
Etb Receptor ◽  
Dose Dependent

Vasoactive peptides may exert inotropic and chronotropic effects in cardiac muscle by modulating intracellular calcium. This study assesses effects of angiotensin II (ANG II) and endothelin-1 (ET-1) on intracellular free calcium concentration ([Ca2+]i) in cultured cardiomyocytes from neonatal and adult rats. [Ca2+]i was measured microphotometrically and by digital imaging using fura 2 methodology. Receptor subtypes through which these agonists induce responses were determined pharmacologically and by radioligand binding studies. ANG II and ET-1 increased neonatal atrial and ventricular cell [Ca2+]i transients in a dose-dependent manner. ANG II (10(-11) to 10(-7) M) failed to elicit [Ca2+]i responses in adult cardiomyocytes, whereas ET-1 increased [Ca2+]i in a dose-dependent manner. The ETA receptor antagonist BQ-123 significantly reduced (P 7< 0.05) ET-1 induced responses, and the ETB receptor agonist IRL-1620 (10(-7) to 10(-5) M) significantly increased (P < 0.05) [Ca2+]i in neonatal and adult cardiomyocytes. ET-1 binding studies demonstrated 85% displacement by BQ-123 and approximately 15% by the ETB receptor agonist sarafotoxin S6c, suggesting a predominance of ETA receptors. Competition binding studies for ANG II failed to demonstrate significant binding on adult ventricular myocytes, indicating the absence or presence of very few ANG II receptors. These data demonstrate that ANG II and ET-1 have stimulatory [Ca2+]i effects on neonatal cardiomyocytes, whereas in adult cardiomyocytes, ANG II-induced effects are insignificant, and only ET-1-induced responses, which are mediated predominantly via ETA receptors, are preserved. Cardiomyocyte responses to vasoactive peptides may thus vary with cardiac development.

Sign in / Sign up

Export Citation Format

Share Document