Role of oxidative stress in angiotensin II-induced enhanced expression of Giα proteins and adenylyl cyclase signaling in A10 vascular smooth muscle cells

2007 ◽  
Vol 292 (4) ◽  
pp. H1922-H1930 ◽  
Author(s):  
Yuan Li ◽  
Georgios Lappas ◽  
Madhu B. Anand-Srivastava
Keyword(s):  
Oxidative Stress ◽  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Adenylyl Cyclase ◽  
Vascular Smooth Muscle Cells ◽  
Ang Ii ◽  
Enhanced Expression

We have previously reported that angiotensin II (ANG II) treatment of A10 vascular smooth muscle cells (VSMCs) increased inhibitory G proteins (Gi protein) expression and associated adenylyl cyclase signaling which was attributed to the enhanced MAP kinase activity. Since ANG II has been shown to increase oxidative stress, we investigated the role of oxidative stress in ANG II-induced enhanced expression of Giα proteins and examined the effects of antioxidants on ANG II-induced enhanced expression of Giα proteins and associated adenylyl cyclase signaling in A10 VSMCs. ANG II treatment of A10 VSMCs enhanced the production of O2− and the expression of Nox4 and P47phox, different subunits of NADPH oxidase, which were attenuated toward control levels by diphenyleneiodonium (DPI). In addition, ANG II augmented the expression of Giα-2 and Giα-3 proteins in a concentration- and time-dependent manner; the maximal increase in the expression of Giα was observed at 1 to 2 h and at 0.1–1.0 μM. The enhanced expression of Giα-2 and Giα-3 proteins was restored to control levels by antioxidants such as N-acetyl-l-cysteine, α-tocopherol, DPI, and apocynin. In addition, ANG II also enhanced the ERK1/2 phosphorylation that was restored to control levels by DPI. Furthermore, the inhibition of forskolin-stimulated adenylyl cyclase activity by low concentrations of 5′- O-(3-triotriphosphate) (receptor-independent Gi functions) and ANG II-, des(Glu18,Ser19,Glu20,Leu21,Gly22)atrial natriuretic peptide4-23-NH2 (natriuretic peptide receptor-C agonist), and oxotremorine-mediated inhibitions of adenylyl cyclase (receptor-dependent functions) that were augmented in ANG II-treated VSMCs was also restored to control levels by antioxidant treatments. In addition, Gsα-mediated diminished stimulation of adenylyl cyclase by stimulatory hormones in ANG II-treated cells was also restored to control levels by DPI. These results suggest that ANG II-induced enhanced levels of Giα proteins and associated functions in VSMCs may be attributed to the ANG II-induced enhanced oxidative stress, which exerts its effects through mitogen-activated protein kinase signaling pathway.

Kinin B1 receptor upregulation by angiotensin II and endothelin-1 in rat vascular smooth muscle cells: receptors and mechanisms

2010 ◽  
Vol 299 (5) ◽  
pp. H1625-H1632 ◽  
Author(s):  
Marielle Morand-Contant ◽  
Madhu B. Anand-Srivastava ◽  
Réjean Couture
Keyword(s):  
Oxidative Stress ◽  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Protein Expression ◽  
Smooth Muscle Cells ◽  
Receptor Antagonist ◽  
Vascular Smooth Muscle Cells ◽  
Ang Ii ◽  
Phosphatidylinositol 3 Kinase

Oxidative stress upregulates the kinin B1 receptor (B1R) in diabetes and hypertension. Since angiotensin II (ANG II) and endothelin-1 (ET-1) are increased in these disorders, this study aims at determining the role of these two prooxidative peptides in B1R expression in rat vascular smooth muscle cells (VSMC). In the A10 cell line and aortic VSMC, ANG II enhanced B1R protein expression in a concentration- and time-dependent manner (maximal at 1 μM and 6 h). In A10 cells, ANG II (1 μM) also increased B1R mRNA expression at 3 h and the activation of induced B1R with the agonist [Sar-d-Phe8]-des-Arg9-BK (10 nM, 5 min) significantly enhanced mitogen -activated protein kinase (MAPK1/2) phosphorylation. The enhancing effect of ANG II on B1R protein expression in A10 cells was normalized by the AT1 (losartan) but not by the AT2 (PD123319) receptor antagonist. Furthermore, it was inhibited by inhibitors of phosphatidylinositol 3-kinase (wortmannin) and NF-κB (MG132) but not of MAPK (PD098059). Whereas the ETB receptor antagonist (BQ788) had no effect, the ETA receptor antagonist (BQ123) blocked the effect of ANG II at 6–8 h but not at an early time point. BQ123 and BQ788 also blocked the increasing effect of ET-1 on B1R protein expression. Antioxidants ( N-acetyl-l-cysteine and diphenyleneiodonium) abolished ANG II- and ET-1-increased B1R protein expression. In conclusion, B1R induction is linked to oxidative stress and activation of phosphatidylinositol 3-kinase and NF-κB. The newly synthesized B1R is functional and can activate MAPK signaling in VSMC. The effect of ANG II is mediated by the AT1 receptor and the subsequent activation of ETA through ET-1 release.

scholarly journals Protein Arginine Methyltransferase 2 Inhibits Angiotensin II-Induced Proliferation and Inflammation in Vascular Smooth Muscle Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Si-yu Zeng ◽  
Jing-fei Luo ◽  
Hai-yan Quan ◽  
Yun-bin Xiao ◽  
Yu-huan Liu ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Ang Ii ◽  
Arginine Methyltransferase ◽  
Vsmcs Proliferation

Objectives. Protein arginine methyltransferase 2 (PRMT2) protects against vascular injury-induced intimal hyperplasia; however, little is known about the role of PRMT2 in angiotensin II (Ang II)-induced VSMCs proliferation and inflammation. This research aims to determine whether PRMT2 inhibits Ang II-induced proliferation and inflammation of vascular smooth muscle cells (VSMCs). Materials and Methods. PRMT2 overexpression was used to elucidate the role of PRMT2 in Ang II-induced VSMCs proliferation and inflammation. Western blotting and reverse transcriptional PCR were adopted to detect protein and mRNA expression severally. Cell viability was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay and cell cycle distribution by flow cytometry. Results. Ang II significantly reduced mRNA and protein levels of PRMT2 in VSMCs in time-dependent and dose-dependent manner. Results of PRMT2 overexpression indicated that PRMT2 inhibited proliferation of VSMCs stimulated with 100 nmol/L Ang II for 24 hours. Furthermore, overexpression of PRMT2 reduced Ang II-induced production of proinflammatory cytokines such as interleukin 6 (IL-6) and interleukin 1β (IL-1β) in VSMCs. Conclusions. These findings suggest that PRMT2 alleviates Ang II-induced VSMCs proliferation and inflammation, providing a new mechanism about how Ang II mediated VSMCs proliferation and inflammation.

Angiotensin II -induced overexpression of Sirtuin-1 contributes to enhanced expression of Giα proteins and hyperproliferation of vascular smooth muscle cells.

2021 ◽  
Author(s):  
Ekhtear Hossain ◽  
Yuan Li ◽  
Madhu B. Anand-Srivastava
Keyword(s):  
Cell Cycle ◽  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Ang Ii ◽  
Cell Cycle Proteins ◽  
Enhanced Expression

Angiotensin II (Ang II) plays an important role in the regulation of various physiological functions including proliferation, hypertrophy of vascular smooth muscle cells (VSMC) through the overexpression of Giα proteins. Sirtuin1 (Sirt1), a class III histone deacetylase and epigenetic regulator is implicated in a wide range of cellular functions, including migration and growth of VSMC as well as in Ang II-induced hypertension. The present study was undertaken to examine the role of Sirt1 in Ang II-induced overexpression of Giα proteins and hyperproliferation of aortic VSMC. We show that Ang II treatment of VSMC increased the expression of Sirt1 which was attenuated by AT1 and AT2 receptor antagonists, losartan and PD123319 respectively. In addition, knockdown of Sirt1 by siRNA attenuated Ang II-induced overexpression of Giα-2 and Giα-3 proteins, hyperproliferation of VSMC as well as the overexpression of cell cycle proteins, cyclin D1, Cdk4 and phosphorylated retinoblastoma proteins. Furthermore, Ang II-induced increased levels of superoxide anion (O2-) and NADPH oxidase activity and increased phosphorylation of ERK1/2 and AKT that are implicated in enhanced expression of Giα proteins and hyperproliferation of VSMC were also attenuated to control levels by silencing of Sirt1. In addition, depletion of Sirt1 by siRNA also attenuated Ang II-induced enhanced phosphorylation of PDGFR, EGFR and IGFR in VSMC. In summary, our results demonstrate that Ang II increased the expression of Sirt1 which through oxidative stress, growth factor receptor-mediated MAP kinase/AKT signaling pathway enhances the expression of Giα proteins and cell cycle proteins and results in the hyperproliferation of VSMC.

Role of cyclic AMP response element binding protein (CREB) in angiotensin II-induced responses in vascular smooth muscle cells

2020 ◽  
Author(s):  
Vanessa Truong ◽  
Madhu B Anand-Srivastava ◽  
Ashok K Srivastava
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Ang Ii ◽  
Response Element ◽  
And Migration

Cyclic adenosine monophosphate response element (CRE) binding protein (CREB) is a nuclear transcription factor that regulates the transcription of several genes containing the CRE sites in their promoters. CREB is activated by phosphorylation on a key serine residue, Ser 311, in response to a wide variety of extracellular stimuli including angiotensin II (Ang II). Ang II is an important vasoactive peptide and mitogen for vascular smooth muscle cells (VSMC) that in addition to regulating the contractile response in VSMC also plays an important role in phenotypic switch of vascular smooth muscle cells (VSMC) from contractile to a synthetic state. The synthetic VSMC are known to exhibit proliferative and migratory properties due to hyperactivation of Ang II-induced signaling events. Ang II has been shown to induce CREB phosphorylation/activation and transcription of genes implicated in proliferation, growth and migration. Here, we have highlighted some key studies that have demonstrated an important role of CREB in Ang II-mediated gene transcription, proliferation, hypertrophy and migration of VSMC.

Implication of multiple signaling pathways in the regulation of angiotensin II induced enhanced expression of Giα proteins in vascular smooth muscle cells

2012 ◽  
Vol 90 (8) ◽  
pp. 1105-1116 ◽  
Author(s):  
Yuan Li ◽  
Madhu B. Anand-Srivastava
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Receptor Antagonist ◽  
Signaling Pathways ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Ang Ii ◽  
Enhanced Expression

We have previously shown that A10 vascular smooth muscle cells (VSMC) exposed to angiotensin II (Ang II) exhibited overexpression of Giα proteins. In the present study, we examined the involvement of different signaling pathways in regulating Ang II induced enhanced expression of Giα proteins in VSMC by using pharmacological inhibitors. Ang II induced increased expression of Giα proteins in A10 VSMC was markedly attenuated by actinomycin D, losartan (an AT1 receptor antagonist), dibutyryl cAMP, phospholipase C (PLC) inhibitor U73122, protein kinase C (PKC) inhibitors staurosporine and GP109203X, but not by PD123319 (an AT2 receptor antagonist). In addition, BAPTA-AM and TMB-8 (chelators of intracellular Ca2+); and nifedipine (a blocker of L-type Ca2+ channels) significantly inhibited Ang II induced enhanced expression of Giα proteins. On the other hand, extracellular Ca2+ chelation using EGTA did not affect the Ang II evoked enhanced levels of Giα proteins. Furthermore, pretreatment of A10 VSMC with calmidazolium (an inhibitor of calmodulin), or KN93 (an inhibitor of CaM kinase), or genistein (an inhibitor of protein tyrosine kinase, PTK), also attenuated the increased levels of Giα proteins induced by Ang II. These results suggest that Ang II induced enhanced expression of Giα proteins may be regulated by different signaling pathways through AT1 receptors in A10 VSMC.

Angiotensin-II-induced enhanced expression of Gi proteins is attenuated by losartan in A10 vascular smooth muscle cells: role of AT1 receptors

2003 ◽  
Vol 81 (2) ◽  
pp. 150-158 ◽  
Author(s):  
Madhu B Anand-Srivastava ◽  
Anuradha Palaparti
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Smooth Muscle Cells ◽  
Adenylyl Cyclase ◽  
Muscle Cells ◽  
Ang Ii ◽  
Enhanced Expression ◽  
Losartan Treatment ◽  
Gi Proteins

We have previously shown that treatment of A10 vascular smooth muscle cells (VSMCs) with angiotensin II (Ang II) enhanced the expression of inhibitory guanine nucleotide regulatory proteins (Giα2 and Giα3). In the present studies, we have investigated the role of type 1 angiotensin receptors (AT1) in the Ang-II-induced enhanced expression of Giα proteins and their functions in A10 SMCs. Ang II enhanced the levels of Giα2 and Giα3 proteins and their mRNA, as determined by Western and Northern blot analysis, respectively; losartan treatment attenuated the enhanced expression of Giα2 and Giα3 proteins and their mRNA in a concentration-dependent manner. In addition, the inhibition of adenylyl cyclase induced by Ang II and des(Glu18,Ser19,Glu20,Leu21,Gly22)ANP4–23-NH2 (C-ANP4–23), which was attenuated by Ang-II treatment, was partially restored by losartan treatment. Similarly, losartan was also able to restore the Ang-II-induced stimulatory responses of isoproterenol and N-ethylcarboxamide adenosine (NECA) on adenylyl cyclase activity. These results suggest a role for AT1 receptors in Ang-II-evoked increases in Giα protein expression and Gs-mediated stimulation in VSMCs.Key words: angiotensin II, AT1 receptor, Gi proteins, adenylyl cyclase, losartan, A10 smooth muscle cells.

cAMP attenuates the enhanced expression of Gi proteins and hyperproliferation of vascular smooth muscle cells from SHR: role of ROS and ROS-mediated signaling

2013 ◽  
Vol 304 (12) ◽  
pp. C1198-C1209 ◽  
Author(s):  
Svetlana Gusan ◽  
Madhu B. Anand-Srivastava
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Adenylyl Cyclase ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Mapk Signaling ◽  
Ang Ii ◽  
Hypertensive Rats ◽  
Enhanced Expression

We previously showed that angiotensin II (ANG II)-induced overexpression of inhibitory G proteins (Gi) was attenuated by dibutyryl-cAMP (db-cAMP) in A10 vascular smooth muscle cells (VSMC). Since enhanced levels of endogenous ANG II contributed to the overexpression of Gi protein and hyperproliferation of VSMC from spontaneously hypertensive rats (SHR), the present study was therefore undertaken to examine if cAMP could also attenuate the overexpression of Gi proteins and hyperproliferation of VSMC from SHR and to explore the underlying molecular mechanisms responsible for this response. The enhanced expression of Giα proteins in VSMC from SHR and Nω-nitro-l-arginine methyl ester hypertensive rats was decreased by db-cAMP. In addition, enhanced inhibition of adenylyl cyclase by inhibitory hormones and forskolin-stimulated adenylyl cyclase activity by low concentration of GTPγS in VSMC from SHR was also restored to Wistar-Kyoto (WKY) levels by db-cAMP. Furthermore, db-cAMP also attenuated the hyperproliferation and the increased production of superoxide anion, NAD(P)H oxidase activity, overexpression of Nox1/Nox2/Nox4 and p47phox proteins, increased phosphorylation of PDGF-receptor (R), EGF-R, c-Src, and ERK1/2 to control levels. In addition, the protein kinase A (PKA) inhibitor reversed the effects of db-cAMP on the expression of Nox4 and Giα proteins and hyperproliferation of VSMC from SHR to WKY levels, while stimulation of the exchange protein directly activated by cAMP did not have any effect on these parameters. These results suggest that cAMP via PKA pathway attenuates the overexpression of Gi proteins and hyperproliferation of VSMC from SHR through the inhibition of ROS and ROS-mediated transactivation of EGF-R/PDGF-R and MAPK signaling pathways.

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