scholarly journals Rapid desensitization of vasopressin-stimulated phosphatidylinositol 4,5-bisphosphate and phosphatidylcholine hydrolysis questions the role of these pathways in sustained diacylglycerol formation in A10 vascular-smooth-muscle cells

1992 ◽  
Vol 285 (3) ◽  
pp. 759-766 ◽  
Author(s):  
R Plevin ◽  
M J O Wakelam
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Receptor Antagonist ◽  
Vascular Smooth Muscle Cells ◽  
Inositol Phosphates ◽  
Muscle Cells ◽  
Receptor Activation ◽  
V1a Receptor ◽  
In Cells

The kinetics of vasopressin-stimulated PtdIns(4,5)P2 and phosphatidylcholine (PtdCho) hydrolysis in relation to sustained diacylglycerol (DAG) formation was investigated in A10 vascular-smooth-muscle cells in culture. Vasopressin stimulated a transient increase in Ins(1,4,5)P3 mass formation, which was mirrored by a decrease in PtdIns(4,5)P2 mass levels. Vasopressin stimulated sustained accumulation of total [3H]inositol phosphates ([3H]IP) in the presence of Li+; however, this was significantly decreased by adding a vasopressin-receptor antagonist at different times after initial stimulation. Vasopressin-stimulated phospholipase D (PLD) activity was found to be a transient phenomenon lasting approx. 2 min. Experiments involving agonist preincubation with subsequent addition of butanol confirmed that vasopressin-stimulated PLD activity was desensitized. Vasopressin stimulated an increase in formation of choline, but not of phosphocholine, suggesting that PLD was the major catalytic route of PtdCho hydrolysis in this cell line. The roles of choline and inositol phospholipid hydrolysis in the prolonged phase of DAG formation was examined by comparing vasopressin-stimulated changes in DAG levels in the presence of butanol, the protein kinase C inhibitor Ro-31-8220 or a V1a-receptor antagonist. Vasopressin-stimulated DAG formation was decreased by 40-50% in the presence of butanol between 1 and 10 min; however, during more prolonged stimulation butanol was without significant effect. In cells pretreated with Ro-31-8220, vasopressin-stimulated DAG formation was decreased by approx. 30% at 2 min, but was significantly potentiated at later times. This coincided with an enhancement of vasopressin-stimulated [3H]IP accumulation. In cells exposed to the V1a-receptor antagonist 5 min after addition of vasopressin, subsequent DAG formation was significantly decreased, indicating that sustained formation of DAG, like [3H]IP accumulation, was dependent on continual agonist receptor activation. The results are discussed in terms of different phospholipid-hydrolytic pathways providing DAG generation.

Cyclooxygenase-2 induction by bradykinin in aortic vascular smooth muscle cells

2006 ◽  
Vol 290 (1) ◽  
pp. H30-H36 ◽  
Author(s):  
Jorge A. Rodriguez ◽  
Paula De la Cerda ◽  
Eileen Collyer ◽  
Valerie Decap ◽  
Carlos P. Vio ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Receptor Antagonist ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Receptor Activation ◽  
Atheromatous Plaque ◽  
Protein Levels ◽  
Cox 2

Vascular smooth muscle cell proliferation and migration play an important role in the pathophysiology of several vascular diseases, including atherosclerosis. Prostaglandins that have been implicated in this process are synthesized by two isoforms of cyclooxygenase (COX), with the expression of the regulated COX-2 isoform increased in atherosclerotic plaques. Bradykinin (BK), a vasoactive peptide increased in inflammation, induces the formation of prostaglandins through specific receptor activation. We hypothesized that BK plays an important role in the regulation of COX-2, contributing to the increase in production of prostaglandins in vascular smooth muscle cells. Herein we examined the signaling pathways that participate in the BK regulation of COX-2 protein levels in primary cultured aortic vascular smooth muscle cells. We observed an increase in COX-2 protein levels induced by BK that was maximal at 24 h. This increase was blocked by a B2 kinin receptor antagonist but not a B1 receptor antagonist, suggesting that the B2 receptor is involved in this pathway. In addition, we conclude that the activation of mitogen-activated protein kinases p42/p44, protein kinase C, and nitric oxide synthase is necessary for the increase in COX-2 levels induced by BK because either of the specific inhibitors for these enzymes blocked the effect of BK. Using a similar approach, we further demonstrated that reactive oxygen species and cAMP were not mediators on this pathway. These results suggest that BK activates several intracellular pathways that act in combination to increase COX-2 protein levels. This study suggests a role for BK on the evolution of the atheromatous plaque by virtue of controlling the levels of COX-2.

Abstract 465: The CB2 Cannabinoid Receptor Mediates the Anti-Proliferative Actions of Angiotensin-(1-7) in Vascular Smooth Muscle Cells

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
E. Ann Tallant ◽  
Allyn Howlett ◽  
Megan Grabenauer ◽  
Brian F Thomas ◽  
Patricia E Gallagher
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Receptor Antagonist ◽  
Vascular Smooth Muscle Cells ◽  
Vascular Injury ◽  
Muscle Cells ◽  
Receptor Activation ◽  
Cb2 Receptor ◽  
Vascular Proliferation

Therapeutic interventions to reduce vascular proliferation are critical for the effective treatment of hypertension-induced end-organ damage, restenosis and atherosclerosis. We showed that angiotensin-(1-7) [Ang-(1-7)] reduces neointimal formation following vascular injury and inhibits vascular growth, through activation of the AT7 receptor mas and production of arachidonic acid derivatives. Endocannaboids (ECs) derived from membrane phospholipids also inhibit vascular proliferation and reduce growth following vascular injury, by stimulation of the CB2 receptor. The impact of CB2 receptor blockade on the anti-proliferative actions of Ang-(1-7) was investigated to assess a potential interaction between the EC and Ang-(1-7)/mas receptor systems. Rat thoracic aortic vascular smooth muscle cells (VSMCs) were treated with platelet-derived growth factor (PDGF) to stimulate growth and incubated with Ang-(1-7), the AT7 receptor antagonist [D-alanine7]-angiotensin-(1-7) [Dala], the CB2 receptor agonist HU308 and/or the CB2 receptor antagonist AM630. PDGF-stimulated VSMC growth was markedly reduced by Ang-(1-7) (74 ± 6% of control, n = 10, p<0.0001) and this effect was blocked by Dala (116 ± 14% of control, n = 4; n.s.). The Ang-(1-7)-mediated reduction in growth was abolished by the CB2 receptor antagonist AM630 (136 ± 16% of control, n = 4; n.s.); AM630 alone had no effect. In contrast, the CB1 receptor antagonist AM281 did not prevent the inhibitory actions of Ang-(1-7) on VSMC growth. CB2 receptor activation by the agonist HU308 also reduced PDGF-stimulated VSMC proliferation to a similar extent as Ang-(1-7) (67 ± 4% of control, n = 5, p<0.001); Dala did not influence the response to HU308 (50 ± 10% of control, n = 5, p<0.005). Ang-(1-7) significantly increased the endogenous cannabinoid 2-arachidonoylglycerol (2-AG) by 48% in VSMC by 24 h (p<0.05, n = 4). We conclude that the growth inhibitory properties of Ang-(1-7) involve a novel pathway culminating in the downstream formation of 2-AG and subsequent activation of the CB2 receptor in VSMC. Thus, Ang-(1-7) and/or CB2 receptor activation may constitute a new and beneficial therapeutic strategy for the prevention of vascular proliferation that is prevalent in cardiovascular disease.

scholarly journals Angiotensin II type 2 receptor activation induces RhoA inhibition through Phosphorylation of its Serine 188 in Vascular Smooth Muscle Cells

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Malvyne Rolli‐Derkinderen ◽  
Christophe Guilluy ◽  
Laurent Loufrani ◽  
Daniel Henrion ◽  
Gervaise Loirand ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Receptor Activation

The Apoptotic Effect of Angiotensin II in Human Vascular Smooth Muscle Cells

2000 ◽  
Vol 6 (S2) ◽  
pp. 636-637
Author(s):  
E. Ou ◽  
C. Wei
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Receptor Antagonist ◽  
Vascular Smooth Muscle Cells ◽  
Artery Bypass ◽  
Muscle Cells ◽  
Tunel Staining ◽  
Apoptotic Effect

Angiotensin II is a potent vasoconstrictor and mitogenic factor. However, the effects of angiotensin II on human vascular smooth muscle cells apoptosis remain controversial. Therefore, the current study was designed to investigate the actions of angiotensin II on human vascular smooth muscle cells apoptosis.Human saphenous vein was obtained from coronary artery bypass surgery (n=6) and was minced and incubated in the special tissue culture system in the absence or presence of angiotensin II (10-6 to 10-12M) for 1, 2, 4, 8, 16, & 24 hours. These studies were repeated with losartan (10-6M, AT- 1 receptor antagonist) and PD-123319 (10-6M, AT-2 receptor antagonist). To detect the DNA fragmentation, in situ terminal deoxymucleotidyl transferase dUTP nick end labeling (TUNEL) and DNA agarose gel analyses were performed. An average of 1000 nuclei was analyzed for TUNEL studies.TUNEL staining and DNA gel analysis demonstrated that angiotensin II increased apoptosis in human vascular smooth muscle cells.

scholarly journals Upregulation of vasopressin V1A receptor mRNA and protein in vascular smooth muscle cells following cyclosporin A treatment

2001 ◽  
Vol 132 (4) ◽  
pp. 909-917 ◽  
Author(s):  
Florence Cottet-Maire ◽  
Pavel V Avdonin ◽  
Emmanuelle Roulet ◽  
Timo M Buetler ◽  
Nicolas Mermod ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Cyclosporin A ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Receptor Mrna ◽  
V1a Receptor ◽  
Vasopressin V1a Receptor

Regulation of endothelin-mediated calcium mobilization in vascular smooth muscle cells by isoproterenol

1991 ◽  
Vol 260 (3) ◽  
pp. C492-C502 ◽  
Author(s):  
Y. T. Xuan ◽  
W. D. Watkins ◽  
A. R. Whorton
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Inositol Phosphates ◽  
Fold Increase ◽  
Muscle Cells ◽  
Beta Agonist ◽  
Intracellular Camp ◽  
Permeabilized Cells

We have investigated the effect of isoproterenol on endothelin-induced Ca2+ mobilization in A10 vascular smooth muscle cells. Endothelin (ET) stimulates a rapid and sustained elevation of intracellular Ca2+ mediated by production of inositol phosphates, release of intracellular Ca2+, and activation of a plasmalemmal Ca2+ influx pathway. This influx pathway appears to be a L-type channel because it is inhibited by nicardipine and activated by BAY K 8644. Depolarization of the cells, by elevating extracellular K+, activated a pharmacologically similar channel and produced a similar change in intracellular Ca2+ concentration. Preincubation of cells with isoproterenol reduced the peak Ca2+ response to endothelin and blocked the sustained elevation. However, isoproterenol did not alter K(+)-induced Ca2+ entry. Thus it appears that ET-induced entry is mediated by intracellular signals and not by depolarization. With the use of cells incubated in Ca2(+)-free medium containing 1 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, isoproterenol was shown to inhibit Ca2+ release from intracellular pools by 36 +/- 3%. Furthermore, isoproterenol pretreatment or addition of adenosine 3',5'-cyclic monophosphate (cAMP) to saponin-permeabilized cells inhibited inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]-induced Ca2+ release from intracellular sites. Similar effects were seen with forskolin. Propranolol reversed the inhibitory effects of isoproterenol. Isoproterenol pretreatment also inhibited the rapid formation of Ins(1,4,5)P3 and [2-3H]inositol 1,3,4,5-tetrakisphosphate stimulated by endothelin and reduced the sustained formation of these compounds. Finally, isoproterenol and forskolin led to a greater than 10-fold increase in intracellular cAMP levels. This stimulation of adenylate cyclase by isoproterenol was completely blocked by propranolol. It appears then that the beta-agonist isoproterenol interacts with a beta-adrenergic receptor, elevates cAMP, and thereby alters endothelin-induced Ca2+ mobilization. Inhibition of Ins(1,4,5)P3 formation, reduction in the responsiveness of the Ins(1,4,5)P3 intracellular receptor, and perhaps inhibition of ET-induced Ca2+ entry appear to be involved.

scholarly journals Glucocorticoids stimulate collagen and noncollagen protein synthesis in cultured vascular smooth muscle cells.

1984 ◽  
Vol 98 (2) ◽  
pp. 541-549 ◽  
Author(s):  
D C Leitman ◽  
S C Benson ◽  
L K Johnson
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Specific Activity ◽  
Fold Increase ◽  
Muscle Cells ◽  
Type I ◽  
Twofold Increase ◽  
In Cells

The effect of glucocorticoids on collagen synthesis was examined in cultured bovine aortic smooth muscle (BASM) cells. BASM cells treated with 0.1 microM dexamethasone during their proliferative phase (11 d) were labeled with [3H]proline for 24 h, and the acid-precipitable material was incubated with bacterial collagenase. Dexamethasone produced an approximate twofold increase in the incorporation of proline into collagenase-digestible protein (CDP) and noncollagen protein (NCP) in the cell layer and medium. The stimulation was present in both primary mass cultures and cloned BASM. An increase in CDP and NCP was detected at 0.1 nM, while maximal stimulation occurred at 0.1 microM. Only cells exposed to dexamethasone during their log phase of growth (1-6 d after plating) showed the increase in CDP and NCP when labeled 11 d after plating. The stimulatory effect was observed in BASM cells treated with the natural bovine glucocorticoid, cortisol, dexamethasone, and testosterone, but was absent in cells treated with aldosterone, corticosterone, cholesterol, 17 beta-estradiol, and progesterone. The increase in CDP and NCP was absent in cells treated with the inactive glucocorticoid, epicortisol, and totally abolished by the antagonist, 17 alpha-hydroxyprogesterone, suggesting that the response was mediated by specific cytoplasmic glucocorticoid receptors. Dexamethasone-treated BASM cells showed a 4.5-fold increase in the specific activity of intracellular proline, which was the result of a twofold increase in the uptake of proline and depletion of the total proline pool. After normalizing for specific activity, dexamethasone produced a 2.4- and 2.8-fold increase in the rate of collagen and NCP synthesis, respectively. Cells treated with dexamethasone secreted 1.7-fold more collagen protein in 24 h compared to control cultures. The BASM cells secreted 70% Type I and 30% Type III collagen into the media as assessed by two-dimensional gel electrophoresis. The ratio of these two types was not altered by dexamethasone. The results of the present study demonstrate that glucocorticoids can act directly on vascular smooth muscle cells to increase the synthesis and secretion of collagen and NCP.

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