Abstract 674: Coupling Factor 6 Activates c-Src By Intracellular Acidosis And Enhances Calcium Signaling In Resistance Arteriole Smooth Muscle Cells

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Tomohiro Osanai ◽  
Makoto Tanaka ◽  
Hirofumi Tomita ◽  
Masahiro Yamada ◽  
Sin Saitoh ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Atp Synthase ◽  
Muscle Cells ◽  
Coupling Factor ◽  
Ang Ii ◽  
Β Subunit ◽  
Intracellular Acidosis ◽  
Coupling Factor 6 ◽  
Sustained Increase

In vascular endothelial cells, coupling factor 6 (CF6) binds to the β subunit of plasma membrane ATP synthase and attenuates prostacyclin generation by inducing intracellular acidosis. However, intracellular signaling in resistance arterioles that is directly related to vascular tonus and hypertension has not been determined yet. We investigated the direct effect of CF6 on Ca 2+ signaling, involvement of c-Src in it, and the role of CF6 in the pathogenesis of hypertension. CF6 at 10 −7 M induced a monophasic increase in intracellular free Ca 2+ concentration ([Ca 2+ ] i ) in A7r5 cells (rat vascular smooth muscle cells (VSMC) expressing voltage-gated Ca 2+ channel). When CF6 at 10 −7 M was added after pretreatment with nifedipine at 10 −5 M, the sustained increase in [Ca 2+ ] i was abolished. In cultured resistance arteriole VSMC obtained from the mesenteric artery network of spontaneously hypertensive rats (SHR, n = 8) and Wistar Kyoto rats (WKY, n = 8), angiotensin II (Ang II) at 10 −7 M caused a spike increase in [Ca 2+ ] i followed by a sustained increase. When Ang II at 10 −7 M was added after pre-administration of CF6 at 10 −7 M, the spike phase of [Ca 2+ ] i was enhanced and it was greater in SHR than in WKY (412 ± 26 vs 162 ± 14 nM, p < 0.05). Pretreatment with PP1 at 50 μM, a c-Src inhibitor, blocked not only the CF6-induced Ca 2+ influx but the CF6-induced increase in the AngII-mediated spike phase of [Ca 2+ ] i . CF6 receptor of VSMC was the β-subunit of ATP synthase, and the affinity was higher in SHR than in WKY (Kd: 3.6 ± 0.3 vs 9.6 ± 0.3 nM, p < 0.05). The increase in ATPase activity by CF6 was greater in SHR than in WKY (p < 0.05), and the decrease in intracellular pH was greater in SHR than in WKY (0.26 ± 0.03 vs 0.13 ± 0.02, p < 0.05). CF6 activated c-Src at 15 minutes by 2 folds greater in SHR than in WKY, and it was blocked by efrapeptine at 10 −5 M, an ATPase inhibitor. In mesenteric arterioles obtained from CF6-transgenic mice (2 fold over-expressed), AngII caused greater vasoconstriction by 2 folds than in those from wild mice (p < 0.05), but it was abolished by pretreatment with PP1. These suggest that CF6 activates c-Src by inducing intracellular acidosis and enhances Ca 2+ signaling in resistance arteriole VSMC. Since the c-Src activation was enhanced in SHR, CF6 might be involved in the genesis of hypertension.

Angiotensin II modulates frizzled-2 receptor expression in rat vascular 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 ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Ang Ii ◽  
Aortic Smooth Muscle

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.

Abstract 477: Diverse Actions of the EP4 Prostaglandin E2 Receptor in Blood Pressure Control

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Marcela Herrera ◽  
Matthew A Sparks ◽  
Beverky H Koller ◽  
Thomas M Coffman
Keyword(s):  
Smooth Muscle ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Smooth Muscle Cells ◽  
Prostaglandin E2 ◽  
Ductus Arteriosus ◽  
Muscle Cells ◽  
High Salt ◽  
Ang Ii ◽  
The Impact

Prostaglandin E2 (PGE2) is a major prostanoid produced by the kidney having the potential to influence renal blood flow, Na excretion, and thus mean arterial pressure (BP). PGE2 actions are mediated by four distinct E-prostanoid (EP) receptor isoforms: EP1-EP4. The EP4 receptor (EP4R) triggers macula densa stimulation of renin, induces vasodilation, and may inhibit epithelial sodium transport. Thus, the impact of EP4Rs on BP may differ with the sites of PGE2 synthesis and pattern of EP4R activation within the kidney. To examine the role of EP4R on BP regulation we generated EP4R-deficient mice. Because deletion of EP4R in utero causes peri-natal mortality due to persistent patent ductus arteriosus, we carried out conditional deletion by crossing EP4flox/flox with a transgenic line with tamoxifen-inducible Cre expression in all tissues. Resting mean arterial pressure (MAP) measured by radiotelemetry was increased by 5±1mm Hg (p<0.05) in mice with total-body EP4R-deficiency (EP4R-TBKO) vs. controls. In addition, EP4R-TBKOs had an exaggerated increase in MAP with high-salt (6% NaCl) feeding (MAP increase: 5±1 vs. 2±1mmHg for controls; p<0.05) and during angiotensin II (Ang II)-dependent hypertension (MAP increase: 37±2 vs. 24±3mmHg for controls; p<0.05). We next hypothesized that exaggerated hypertension in the EP4R-TBKOs was due to elimination of compensatory EP4R-depedent vasodilation mediated by direct actions in vascular smooth muscle cells (VSMCs). Accordingly, we generated mice lacking EP4R in VSMCs (EP4R-SMKOs) using EP4flox/flox and transgenic mice with tamoxifen-inducible expression of Cre limited to smooth muscle cells. In contrast to the EP4R-TBKOs, elimination of EP4R only from VSMC reduced resting MAP by 5±1mm Hg (p<0.04) but did not affect the BP response to high salt feeding (MAP change: 2±1 vs. 2±1 mm Hg; ns) or chronic Ang II infusion (MAP increase: 29±3 vs. 34±4 mm Hg; ns). Thus, the EP4R modulates resting MAP but its specific impact may vary between EP4R populations in different cell lineages. EP4Rs resist the development of salt- and Ang II-dependent hypertension. These anti-hypertensive actions are not mediated by direct effects of EP4R in VSMCs, but may involve EP4R in endothelium, brain, or kidney epithelia.

Fatty acid inhibition of angiotensin II-stimulated inositol phosphates in smooth muscle cells

1993 ◽  
Vol 264 (2) ◽  
pp. H595-H603
Author(s):  
M. E. Ullian
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Smooth Muscle Cells ◽  
Receptor Binding ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Muscle Cells ◽  
Ang Ii ◽  
Guanine Nucleotide Binding Protein ◽  
Cellular Incorporation

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.

scholarly journals Nox5 in Vascular Smooth Muscle Cells Mediates Ang II‐Induced Renal Fibrosis and Inflammation

2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Augusto Montezano ◽  
Francisco Rios ◽  
Livia Camargo ◽  
Roberto Palacios‐Ramirez ◽  
Antoine Tarjus ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Renal Fibrosis ◽  
Muscle Cells ◽  
Ang Ii

Abstract 361: Cyclophilin A Mediates Angiotensin II--Stimulated NADPH Oxidase Activation in Vascular Smooth Muscle Cells

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Nwe Nwe Soe ◽  
Mark Sowden ◽  
Patrizia Nigro ◽  
Bradford C Berk
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Nadph Oxidase ◽  
Smooth Muscle Cells ◽  
Fold Increase ◽  
Muscle Cells ◽  
Dependent Manner ◽  
Ang Ii ◽  
Membrane Translocation ◽  
Ppiase Activity

Objective: Cyclophilin A (CyPA) is a ubiquitously expressed cytosolic protein that possesses PPIase activity and scaffold function. CyPA regulates Angiotensin II (Ang II) induced reactive oxygen species (ROS) production in vascular smooth muscle cells. However, the mechanism of this CyPA regulation remains unclear. We hypothesized that CyPA regulates plasma membrane translocation of NADPH oxidase cytosolic subunit, p47phox, which is required for NADPH oxidase structural organization and activity. Methods and results: Immunofluorescence studies in rat aortic smooth muscle cells revealed that CyPA translocated from the cytosol to the plasma membrane in response to Ang II in a time dependent manner with a peak at 10min (46.4±5.4 fold increase). Mouse Aortic Smooth Muscle Cells (MASM) were isolated from mice lacking CyPA (CyPA-/-) and wild type controls (WT), treated with Ang II (100nM) and immunofluorescence analysis was performed. Ang II induced p47phox plasma membrane translocation at 10min in WT mice. However, p47 phox translocation was significantly inhibited in CyPA -/- MASM. CyPA and p47phox colocalized at the plasma membrane in response to Ang II. Further analysis using subcellular fractionation studies confirmed that Ang II induced p47phox plasma membrane translocation was inhibited in CyPA -/- MASM compared to WT (1.2±2.7 vs 4.3±3.4 fold increase). Coimmunoprecipitation analyses confirmed that Ang II increased CyPA association with p47phox in a time dependent manner (2.5±3.4 fold increase at 10min). Finally, pretreatment with the PPIase activity inhibitor, cyclosporine A (1uM), could not inhibit CyPA association with p47phox and CyPA mediated p47phox translocation to the plasma membrane. Conclusion: These data suggest that Ang II promotes an association between CyPA and p47phox that enhances plasma membrane translocation of p47phox. This is proposed to increase the NADPH oxidase activity thereby increasing cellular ROS production. This process is independent of the PPIase activity of CyPA. Therefore, inhibition of the CyPA and p47phox association could be a future therapeutic target for Ang II induced ROS regulated cardiovascular diseases such as atherosclerosis and abdominal aortic aneurysm formation.

PDGF-BB-induced DNA synthesis is delayed by angiotensin II in vascular smooth muscle cells

1998 ◽  
Vol 274 (5) ◽  
pp. H1742-H1748 ◽  
Author(s):  
Gunilla Dahlfors ◽  
Yun Chen ◽  
Maria Wasteson ◽  
Hans J. Arnqvist
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Smooth Muscle Cells ◽  
Dna Synthesis ◽  
Receptor Antagonist ◽  
Muscle Cells ◽  
Inhibitory Effect ◽  
Ang Ii ◽  
Β Receptor ◽  
Tgf Β1

The interaction of ANG II with platelet-derived growth factor (PDGF)-BB-induced DNA synthesis was studied in cultured rat aortic smooth muscle cells. PDGF-BB-induced DNA synthesis was delayed (∼6–8 h) by ANG II as shown by a time-course experiment. Losartan, an AT1-receptor antagonist, blocked the transient inhibitory effect of ANG II, whereas the AT2-receptor antagonist PD-123319 had no effect. Autocrine- or paracrine-acting transforming growth factor-β1 (TGF-β1), believed to be a mediator of ANG II-induced inhibitory effects, was not responsible for the delay of PDGF-BB-induced DNA synthesis, because a potent TGF-β1 neutralizing antibody could not reverse this effect of ANG II, nor was the delay of the PDGF-BB effect caused by inhibition of PDGF-β-receptor phosphorylation as shown by Western blot analysis of immunoprecipitated PDGF-β receptor. In conclusion, our results show that ANG II can exert a transient inhibitory effect on PDGF-BB-induced proliferation via the AT1 receptor.

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