scholarly journals Evidence for a protein S receptor(s) on human vascular smooth muscle cells. Analysis of the binding characteristics and mitogenic properties of protein S on human vascular smooth muscle cells

1995 ◽  
Vol 308 (2) ◽  
pp. 481-485 ◽  
Author(s):  
O Benzakour ◽  
C Formstone ◽  
S Rahman ◽  
C Kanthou ◽  
U Dennehy ◽  
...  

The presence of specific binding sites for the coagulation factor protein S (PS) on the surface of human vascular smooth muscle cells (HVSMC) is described. The binding characteristics of 125I-PS to HVSMC were studied and found to be saturable, reversible and, as described by the Hill equation, co-operative (h 1.74; Kd 0.33 nM). Autoradiographic analysis of detergent extracts of HVSMC chemically cross-linked with 125I-PS and separated by SDS/PAGE revealed radioactivity associated with two proteins with apparent molecular masses of 220 and 230 kDa respectively. The mitogenic activity of PS on HVSMC was also investigated. Protein S was shown to stimulate DNA synthesis of growth-arrested HVSMC and to support their proliferation under low-serum conditions in a sustained and dose-dependent manner.

1991 ◽  
Vol 260 (5) ◽  
pp. H1713-H1717 ◽  
Author(s):  
U. Ikeda ◽  
M. Ikeda ◽  
T. Oohara ◽  
A. Oguchi ◽  
T. Kamitani ◽  
...  

We have investigated the effect of interleukin 6 (IL-6) on the growth of vascular smooth muscle cells (VSMC) isolated from rat aortas. Murine recombinant IL-6 significantly increased the number of VSMC and stimulated tritiated thymidine incorporation into VSMC in a dose-dependent manner. The IL-6-induced thymidine incorporation into VSMC was totally inhibited by the Ca2+ channel blocker verapamil; however, IL-6 showed no effects on the intracellular Ca2+ level ([Ca2+]i) in VSMC. Antibody against platelet-derived growth factor (PDGF) also totally inhibited the IL-6-induced thymidine uptake. PDGF caused a significant increase in the [Ca2+]i, which was totally inhibited by verapamil. IL-6 mRNA was not detected in unstimulated “quiescent” VSMC, but its expression was stimulated by exposure of VSMC to 10% fetal bovine serum. Immunohistochemical study using anti-PDGF antibody showed that IL-6 stimulated PDGF production in VSMC. These results support the premise that IL-6 is released by VSMC in an autocrine manner and promotes the growth of VSMC via induction of endogenous PDGF production.


1995 ◽  
Vol 268 (1) ◽  
pp. H404-H410 ◽  
Author(s):  
C. Serradeil-Le Gal ◽  
J. M. Herbert ◽  
C. Delisee ◽  
P. Schaeffer ◽  
D. Raufaste ◽  
...  

The effects of SR-49059, a new nonpeptide and selective arginine vasopressin (AVP) V1a antagonist, were investigated in binding and functional studies on cultured human aortic vascular smooth muscle cells (VSMC). Characterization of human vascular V1a receptors, using a specific V1a radioiodinated ligand, showed that [125I]-linear AVP antagonist binding to human VSMC membranes was time dependent, reversible, and saturable. A single population of high-affinity binding sites (apparent equilibrium dissociation constant = 15 +/- 6 pM; maximum binding density = 36 +/- 5 fmol/mg protein, i.e., approximately 3,000 sites/cell) with the expected V1a profile was identified. Exposure of these cells to AVP dose-dependently produced cytosolic free [Ca2+] increase [AVP concentration required to obtain a half-maximal response (EC50) = 23 +/- 9 nM] and proliferation (EC50 = 3.2 +/- 0.5 nM). SR-49059 strongly and stereospecifically inhibited [125I]-linear AVP antagonist binding to VSMC V1a receptors [inhibition constant (Ki) = 1.4 +/- 0.3 nM], AVP-evoked Ca2+ increase [concentration of inhibitor required to obtain 50% inhibition of specific binding (IC50) = 0.41 +/- 0.06 nM], and the mitogenic effects induced by 100 nM AVP (IC50 = 0.83 +/- 0.04 nM). OPC-21268, another nonpeptide V1a antagonist, was more than two orders of magnitude less potent than SR-49059 in these models. However, the consistent affinity (Ki = 138 +/- 21 nM) and activity found with OPC-21268 on human VSMC in comparison with the inactivity already observed for other human V1a receptors (liver, platelets, adrenals, and uterus) strongly suggested the existence of human AVP V1a-receptor subtypes.(ABSTRACT TRUNCATED AT 250 WORDS)


1991 ◽  
Vol 260 (3) ◽  
pp. C424-C432 ◽  
Author(s):  
M. L. Bea ◽  
J. C. Dussaule ◽  
M. Bens ◽  
R. Ardaillou

Because atrial natriuretic factor (ANF) has been demonstrated to decrease resistances in cortical renal vessels in vivo, we studied 125I-ANF binding and ANF-dependent guanosine 3',5'-cyclic monophosphate (cGMP) production in subcultured vascular smooth muscle cells (VSMC) prepared from the rabbit renal cortex. 125I-ANF specific binding at 4 degrees C represented 70% of total binding and reached a plateau at 30-60 min. Equilibrium saturation binding curves suggested one group of high-affinity receptor sites (KD = 78 +/- 16 pM, Bmax = 45 +/- 11 fmol/mg) but were compatible with several groups exhibiting close binding parameters. ANF, [Ala7,Ala23]ANF (a linear analogue), and C-ANF-(4-23) (a ligand of C receptors) inhibited 125I-ANF binding at 37 degrees C with nearly similar potencies. In contrast, at 4 degrees C, complete or nearly complete inhibition of binding was obtained with ANF and linear ANF, the latter exhibiting the weakest potency, whereas C-ANF-(4-23) displaced only 35% of the tracer. ANF markedly stimulated cGMP accumulation, with a threshold concentration of 10 pM and a stimulation of 115 times basal value at 0.1 microM. Linear ANF was also stimulatory with a much weaker potency. Around 25% of 125I-ANF bound to cell surface was internalized at 37 degrees C. Phenylarsine oxide partially inhibited internalization as well as the inhibitory potency of C-ANF-(4-23) on 125I-ANF binding. As shown by high-performance liquid chromatography extracellular 125I-ANF was rapidly degraded at 37 degrees C into its 125I-COOH-terminal tripeptide and 125I-Tyr.(ABSTRACT TRUNCATED AT 250 WORDS)


1997 ◽  
Vol 273 (2) ◽  
pp. H628-H633 ◽  
Author(s):  
J. W. Gu ◽  
T. H. Adair

We determined whether hypoxia-induced expression of vascular endothelial growth factor (VEGF) can be reversed by a normoxic environment. Dog myocardial vascular smooth muscle cells (MVSMCs) were exposed to hypoxia (1% O2) for 24 h and then returned to normoxia (20% O2). VEGF protein levels increased by more than fivefold after 24 h of hypoxia and returned to baseline within 24 h of the return of the cells to normoxia. Northern blot analysis showed that hypoxia caused a 5.5-fold increase in VEGF mRNA, and, again, the expression was reversed after reinstitution of normoxia. Additional measurements showed that basic fibroblast growth factor and platelet-derived growth factor protein levels were not induced by hypoxia and that hypoxia caused a fourfold decrease in transforming growth factor-beta 1 protein levels. Hypoxia conditioned media from MVSMCs caused human umbilical vein endothelial cells to increase [3H]thymidine incorporation by twofold, an effect that was blocked in a dose-dependent manner by anti-human VEGF antibody. The hypoxia conditioned media had no effect on MVSMC proliferation. These findings suggest that VEGF expression can be bidirectionally controlled by tissue oxygenation, and thus support the hypothesis that VEGF is a physiological regulator of angiogenesis.


2004 ◽  
Vol 23 (4) ◽  
pp. 233-237 ◽  
Author(s):  
Jialin Su ◽  
Jianfeng Li ◽  
Wenyan Li ◽  
Bella T. Altura ◽  
Burton M. Altura

Cocaine abuse is known to induce many adverse cardiovascular effects, including hypertension, atherosclerosis, and aortic dissection. A major physiological event leading to these pathophysiological actions of cocaine could be apoptosis. This study was designed to investigate if primary cultured rat aortic vascular smooth muscle cells (VSMCs) can undergo apoptosis when treated with cocaine. After treatment with cocaine (10−6 to 10−4 M), morphological analysis of aortic VSMCs using confocal fluoresence microscopy showed that the percentage of apoptotic aortic VSMCs increased after cocaine (10−6 to 10−4 M) treatment for 12, 24, and 48 h. These results demonstrate that aortic VSMCs can undergo rapid apoptosis in response to cocaine in a concentration-dependent manner. Cocaine-induced apoptosis may thus play a major role in cocaine abuse-induced aortic dissection, atherosclerosis, and hypertension.


2003 ◽  
Vol 81 (11) ◽  
pp. 1056-1063 ◽  
Author(s):  
Harjot K Saini ◽  
Sushil K Sharma ◽  
Peter Zahradka ◽  
Hideo Kumamoto ◽  
Nobuakira Takeda ◽  
...  

Although serotonin (5-HT) induced proliferation of vascular smooth muscle cells is considered to involve changes in intracellular Ca2+ ([Ca2+]i), the mechanism of Ca2+ mobilization by 5-HT is not well defined. In this study, we examined the effect of 5-HT on rat aortic smooth muscle cells (RASMCs) by Fura-2 microfluorometry for [Ca2+]i measurements. 5-HT was observed to increase the [Ca2+]i in a concentration- and time-dependent manner. This action of 5-HT was dependent upon the extracellular concentration of Ca2+ ([Ca2+]e) and was inhibited by both Ca2+ channel antagonists (verapamil and diltiazem) and inhibitors of sarcoplasmic reticular Ca2+ pumps (thapsigargin and cyclopia zonic acid). The 5-HT-induced increase in [Ca2+]i was blocked by sarpogrelate, a 5-HT2A-receptor antagonist, but not by different agents known to block other receptor sites. 5-HT-receptor antagonists such as ketanserin, cinanserin, and mianserin, unlike methysergide, were also found to inhibit the 5-HT-induced Ca2+ mobilization, but these agents were less effective in comparison to sarpogrelate. On the other hand, the increase in [Ca2+]i in RASMCs by ATP, angiotensin II, endothelin-1, or phorbol ester was not affected by sarpogrelate. These results indicate that Ca2+ mobilization in RASMCs by 5-HT is mediated through the activation of 5-HT2A receptors and support the view that the 5-HT-induced increase in [Ca2+]i involves both the extracellular and intracellular sources of Ca2+.Key words: sarpogrelate, serotonin, vascular smooth muscle cells, intracellular Ca2+.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiong Hu ◽  
Marco Sisignano ◽  
Roman Brecht ◽  
Natarajan Perumal ◽  
Carlo Angioni ◽  
...  

AbstractCytochrome P450 (CYP) signalling pathway has been shown to play a vital role in the vasoreactivity of wild type mouse ophthalmic artery. In this study, we determined the expression, vascular responses and potential mechanisms of the CYP-derived arachidonic acid metabolites. The expression of murine CYP (Cyp2c44) and soluble epoxide hydrolase (sEH) in the wild type ophthalmic artery was determined with immunofluorescence, which showed predominant expression of Cyp2c44 in the vascular smooth muscle cells (VSMC), while sEH was found mainly in the endothelium of the wild type ophthalmic artery. Artery of Cyp2c44−/− and sEH−/− mice were used as negative controls. Targeted mass spectrometry-based lipidomics analysis of endogenous epoxide and diols of the wild type artery detected only 14, 15-EET. Vasorelaxant responses of isolated vessels in response to selective pharmacological blockers and agonist were analysed ex vivo. Direct antagonism of epoxyeicosatrienoic acids (EETs) with a selective inhibitor caused partial vasodilation, suggesting that EETs may behave as vasoconstrictors. Exogenous administration of synthetic EET regioisomers significantly constricted the vessels in a concentration-dependent manner, with the strongest responses elicited by 11, 12- and 14, 15-EETs. Our results provide the first experimental evidence that Cyp2c44-derived EETs in the VSMC mediate vasoconstriction of the ophthalmic artery.


Blood ◽  
2000 ◽  
Vol 95 (6) ◽  
pp. 2008-2014 ◽  
Author(s):  
Omar Benzakour ◽  
Chryso Kanthou

Abstract The anticoagulant factor protein S is a secreted vitamin K-dependent γ-carboxylated protein that is mainly made in the liver. Protein S is homologous to the growth arrest specific protein, Gas6, the expression of which is up-regulated in cultured fibroblasts upon serum withdrawal. We report here the synthesis and secretion of protein S by cultured human vascular smooth muscle cells (HVSMCs). Western blot analysis revealed that similar amounts of protein S are secreted by both growing and growth-arrested HVSMCs. HVSMC-derived protein S was found to be γ-carboxylated as it was precipitated by barium citrate and was shown to possess protein C cofactor activity. Treatment with the vitamin K antagonist warfarin led to the accumulation of intracellular undercarboxylated protein S forms that were rapidly secreted upon the reintroduction of vitamin K. Northern blotting analysis showed that cultured HVSMCs express a protein S transcript. The expression of protein S messenger RNA was unaffected by either warfarin, growth arrest, or various VSMC mitogens, such as platelet-derived growth factor-BB, basic fibroblast growth factor, transforming growth factor-β, or hepatocyte growth factor. Thrombin, however, induced an up-regulation of protein S expression at both messenger RNA and protein levels. The evidence we provide for protein S secretion by cultured HVSMCs and its up-regulation by thrombin, together with earlier reports showing that protein S acts as a mitogen for these cells, suggests that, in addition to its known role in regulating blood clotting, protein S may also be an important autocrine factor in the pathophysiology of the vasculature.


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