THE ROLE OF CALCIUM (CA2+) IN MODULATION OF SMOOTH MUSCLE CELLS REACTIVITY TO ANGIOTENSIN II (ANG II) DURING ISCHEMIA/REPERFUSION (I/R).

2008 ◽  
Vol 86 (Supplement) ◽  
pp. 736
Author(s):  
M Slupski ◽  
K Szadujkis-Szadurska ◽  
R Szadujkis-Szadurski ◽  
M Jasinski ◽  
G Grzesk
2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Si-yu Zeng ◽  
Jing-fei Luo ◽  
Hai-yan Quan ◽  
Yun-bin Xiao ◽  
Yu-huan Liu ◽  
...  

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.


Author(s):  
Vanessa Truong ◽  
Madhu B Anand-Srivastava ◽  
Ashok K Srivastava

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.


2003 ◽  
Vol 81 (2) ◽  
pp. 150-158 ◽  
Author(s):  
Madhu B Anand-Srivastava ◽  
Anuradha Palaparti

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.


2005 ◽  
Vol 108 (6) ◽  
pp. 523-530 ◽  
Author(s):  
Giovanna CASTOLDI ◽  
Serena REDAELLI ◽  
Willy M. M. van de GREEF ◽  
Cira R. T. di GIOIA ◽  
Giuseppe BUSCA ◽  
...  

Ang II (angiotensin II) has multiple effects on vascular smooth muscle cells through the modulation of different classes of genes. Using the mRNA differential-display method to investigate gene expression in rat aortic smooth muscle cells in culture in response to 3 h of Ang II stimulation, we observed that Ang II down-regulated the expression of a member of the family of transmembrane receptors for Wnt proteins that was identified as Fzd2 [Fzd (frizzled)-2 receptor]. Fzds are a class of highly conserved genes playing a fundamental role in the developmental processes. In vitro, time course experiments demonstrated that Ang II induced a significant increase (P<0.05) in Fzd2 expression after 30 min, whereas it caused a significant decrease (P<0.05) in Fzd2 expression at 3 h. A similar rapid up-regulation after Ang II stimulation for 30 min was evident for TGFβ1 (transforming growth factor β1; P<0.05). To investigate whether Ang II also modulated Fzd2 expression in vivo, exogenous Ang II was administered to Sprague–Dawley rats (200 ng·kg−1 of body weight·min−1; subcutaneously) for 1 and 4 weeks. Control rats received normal saline. After treatment, systolic blood pressure was significantly higher (P<0.01), whereas plasma renin activity was suppressed (P<0.01) in Ang II- compared with the saline-treated rats. Ang II administration for 1 week did not modify Fzd2 expression in aorta of Ang II-treated rats, whereas Ang II administration for 4 weeks increased Fzd2 mRNA expression (P<0.05) in the tunica media of the aorta, resulting in a positive immunostaining for fibronectin at this time point. In conclusion, our data demonstrate that Ang II modulates Fzd2 expression in aortic smooth muscle cells both in vitro and in vivo.


1993 ◽  
Vol 264 (2) ◽  
pp. H595-H603
Author(s):  
M. E. Ullian

Inositol phosphate (InsP) responses to angiotensin II (ANG II) stimulation were measured in cultured rat vascular smooth muscle cells (VSMC) incubated with and without fatty acids (FA). VSMC were washed after 24 h of FA incubation to achieve cellular incorporation of FA yet eliminate ambient FA. Incubation with eicosapentaenoic acid (EPA)-supplemented medium resulted in concentration-dependent incorporation of EPA and depletion of arachidonic acid in VSMC membranes. Incubation with EPA, but not other FA, resulted in inhibition of ANG II-stimulated InsP formation (29% inhibition with 100 microM EPA). In contrast, InsP formation in response to guanine nucleotide-binding protein stimulation was not affected by EPA. ANG II receptor binding to membranes prepared from EPA-loaded VSMC was 18% lower than binding in membranes from sham-loaded cells. In other studies, VSMC were exposed acutely to FA to avoid cellular incorporation. Exposure to all FA resulted in concentration-dependent reductions in ANG II binding and ANG II-stimulated InsP formation; binding affinity was reduced without changes in receptor density. We conclude that ANG II-stimulated InsP formation is modestly and selectively inhibited by EPA incorporation and more profoundly inhibited by acute exposure to many FA via interference with ANG II receptor binding.


1990 ◽  
Vol 258 (5) ◽  
pp. C849-C854 ◽  
Author(s):  
S. L. Linas ◽  
R. Marzec-Calvert ◽  
M. E. Ullian

Dietary K depletion (KD) results in increases in the number of angiotensin II (ANG II) receptors and prevents ANG II-induced downregulation of ANG II receptors in membrane preparations of vessels from KD animals. Because dietary KD results in changes in factors other than K, we K depleted vascular smooth muscle cells (VSMC) in culture to determine the specific effects of KD on ANG II receptor expression and processing. Scatchard analysis of ANG II uptake at 4 degrees C revealed that the number of surface receptors was increased by 37% in cells in which K had been reduced by 45%. This increase also occurred in the presence of cycloheximide. To determine the effect of KD on receptor processing, we measured the number of surface receptors after exposure to ANG II in concentrations sufficient to cause down-regulation. After 30-min exposure to ANG II, the number of surface receptors was reduced by 63% in control cells but only 33% in KD cells. Thirty minutes after withdrawing ANG II, surface binding returned to basal levels in control cells but was still reduced by 20% in KD cells. To determine the functional significance of impaired receptor processing, we measured ANG II uptake at 21 degrees C. Uptake at 21 degrees C depends on the functional number of receptors, i.e., the absolute number of surface receptors and the rate at which receptors are recycled to the surface after ANG II binding. ANG II uptake at 21 degrees C was reduced by 50% in KD cells.(ABSTRACT TRUNCATED AT 250 WORDS)


1997 ◽  
Vol 136 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Junji Shinoda ◽  
Osamu Kozawa ◽  
Atsushi Suzuki ◽  
Yasuko Watanabe-Tomita ◽  
Yutaka Oiso ◽  
...  

Abstract In a previous study, we have shown that angiotensin II (Ang II) activates phosphatidylcholinehydrolyzing phospholipase D due to Ang II-induced Ca2+ influx from extracellular space in subcultured rat aortic smooth muscle cells. In the present study, we have investigated the role of phospholipase D in Ang II-induced arachidonic acid (AA) metabolite release and prostacyclin synthesis in subcultured rat aortic smooth muscle cells. Ang II significantly stimulated AA metabolite release in a concentration-dependent manner in the range between 1 nmol/l and 0·1 μmol/l. d,l-Propranolol hydrochloride (propranolol), an inhibitor of phosphatidic acid phosphohydrolase, significantly inhibited the Ang II-induced release of AA metabolites. The Ang II-induced AA metabolite release was reduced by chelating extracellular Ca2+ with EGTA. Genistein, an inhibitor of protein tyrosine kinases, significantly suppressed the Ang II-induced AA metabolite release. 1,6-Bis-(cyclohexyloximinocarbonylamino)-hexane (RHC-80267), a potent and selective inhibitor of diacylglycerol lipase, significantly inhibited the Ang II-induced AA metabolite release. Both propranolol and RHC-80267 inhibited the Ang II-induced synthesis of 6-keto-prostaglandin F1α, a stable metabolite of prostacyclin. The synthesis was suppressed by genistein. These results strongly suggest that the AA metabolite release induced by Ang II is mediated, at least in part, through phosphatidylcholine hydrolysis by phospholipase D activation in aortic smooth muscle cells. European Journal of Endocrinology 136 207–212


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