716 Leptin Promotes the Osteoblast Differentiation and Mineralization of Primary Cultures of Vascular Smooth Muscle Cells by Regulating GSK-3β

2012 ◽  
Vol 28 (5) ◽  
pp. S373-S374
Author(s):  
M.G. Zeadin ◽  
M.K. Butcher ◽  
G.H. Werstuck
2013 ◽  
Vol 91 (3) ◽  
pp. 241-247 ◽  
Author(s):  
Viktoria Youreva ◽  
Georgia Kapakos ◽  
Ashok K. Srivastava

Insulin-like growth factor 1 (IGF-1) is a mitogenic factor that stimulates the signaling pathways responsible for inducing hypertrophic and proliferative responses in vascular smooth muscle cells (VSMC). We have previously demonstrated that IGF-1 receptor (IGF-1R) plays a key role in transducing the hypertrophic and proliferative responses of angiotensin II (Ang-II) and endothelin-1 (ET-1). Curcumin, a polyphenolic compound derived from the spice turmeric is known to possess antiproliferative properties and exerts vasculoprotective effects. However, the ability of curcumin to modulate IGF-1-induced signaling responses in VSMC remains to be investigated. In this study, we determined the effect of curcumin on IGF-1-induced phosphorylation of protein kinase B (PKB), glycogen synthase kinase-3β (GSK-3β), and IGF-1R in VSMC. Curcumin inhibited IGF-1-induced phosphorylation of PKB and GSK-3β as well as the IGF-1R β subunit in a dose-dependent fashion. In addition, IGF-1-induced expression of early growth response protein 1 (Egr-1) which plays a pathogenic role in vascular dysfunctions, was also attenuated by curcumin. In conclusion, these results indicate that curcumin is a potent inhibitor of key components of the IGF-1-induced mitogenic and proliferative signaling system in VSMC, and suggest that curcumin-induced attenuation of these signaling components may constitute a potential mechanism for its vasculoprotective effects.


1992 ◽  
Vol 262 (1) ◽  
pp. C148-C155 ◽  
Author(s):  
J. P. Gardner ◽  
G. Tokudome ◽  
H. Tomonari ◽  
E. Maher ◽  
D. Hollander ◽  
...  

The effects of endothelin-1 (ET) on the cytosolic free Ca (Cai) and cytosolic pH (pHi) were examined in primary cultures of human umbilical artery (HUA) vascular smooth muscle cells (VSMCs), respectively, loaded with fura-2 and 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. In 1 mM Ca, ET produced a dose-dependent, biphasic increase in the signal with a maximal effect at 400 nM ET. At this concentration, ET produced a Cai transient (mean +/- SE; a rise from basal Cai of 86 +/- 16 to 216 +/- 33 nM) that lasted for approximately 50-60 s. The Cai transient was followed by a slow but sustained increase in Cai. Both ET-induced Cai transient and posttransient Cai were attenuated in Ca deficient medium or by verapamil and nicardipine. In contrast to ET, thrombin elicited only a monophasic Cai response in HUA VSMCs. This response was also partially sensitive to Ca removal or verapamil. KCl (45 mM) depolarization did not elicit a Cai response. However, the presence of voltage sensitive Ca channels in HUA VSMCs was demonstrated by enhanced Mn uptake in cells depolarized with KCl. Both ET and thrombin treatment did not alter pHi. HUA VSMCs demonstrated a single class of ET receptors (approximately 13,000 sites/cell) with an equilibrium dissociation constant of 0.34 nM. Nicardipine did not alter ET binding. These observations suggest a dual effect of ET on the Cai profile in HUA VSMCs that is mediated by Ca mobilization and Ca entry through Ca channels. The Ca entry could include influx through receptor-operated Ca channels, voltage-sensitive Ca channels, or both, but without a direct interaction between ET and these channels.


1998 ◽  
Vol 274 (2) ◽  
pp. H448-H455 ◽  
Author(s):  
Todd A. Wyatt ◽  
Allen J. Naftilan ◽  
Sharron H. Francis ◽  
Jackie D. Corbin

Guanosine 3′,5′-cyclic monophosphate (cGMP)-binding, cGMP-specific phosphodiesterase (PDE5) is abundant in vascular smooth muscle, and this enzyme is a potent substrate for cGMP-dependent protein kinase (PKG) in vitro. Binding of cGMP to the allosteric sites of PDE5 is required for this phosphorylation to occur. Vascular smooth muscle cells (VSMC) were used to determine if PDE5 is phosphorylated in intact cells when cGMP is increased. With the use of anti-PDE5 antibodies, a phosphorylated 93-kDa protein band was immunoprecipitated from early passaged primary cultures of VSMC that had been preincubated with32Pito label cellular ATP and then treated with atrial natriuretic factor (ANF). In the absence of ANF, there was no detectable incorporation of radiolabeled phosphate into this band. Phosphorylation of the 93-kDa protein was augmented by pretreating cells with 8-bromoguanosine 3′,5′-cyclic monophosphate (8-BrcGMP) to activate PKG before addition of ANF. 8-BrcGMP, which interacts poorly with the allosteric sites of PDE5, had no effect on PDE5 phosphorylation in the absence of ANF. Phosphorylation of PDE5 in response to treatment of cells with ANF was associated with a two- to fourfold increase in PDE activity in immunoprecipitates. Multiple-passaged VSMC, which are deficient in PKG but retain PDE5, demonstrated no ANF-dependent increase in phosphorylation or catalytic activity of PDE5. However, incubation of immunoprecipitated PDE5 from these cells with purified PKG, cGMP, and a phosphorylation mixture containing [γ-32P]ATP resulted in32Piincorporation into PDE5 that was correlated with increased catalytic activity. These studies are the first to demonstrate phosphorylation of PDE5 in intact cells, thus suggesting a physiological role for this enzyme in smooth muscle regulation.


2014 ◽  
Vol 306 (6) ◽  
pp. F608-F618 ◽  
Author(s):  
Kayoko Miyata ◽  
Ryousuke Satou ◽  
Weijian Shao ◽  
Minolfa C. Prieto ◽  
Maki Urushihara ◽  
...  

In angiotensin II (ANG II)-dependent hypertension, the augmented intrarenal ANG II constricts the renal microvasculature and stimulates Rho kinase (ROCK), which modulates vascular contractile responses. Rho may also stimulate angiotensinogen (AGT) expression in preglomerular vascular smooth muscle cells (VSMCs), but this has not been established. Therefore, the aims of this study were to determine the direct interactions between Rho and ANG II in regulating AGT and other renin-angiotensin system (RAS) components and to elucidate the roles of the ROCK/NF-κB axis in the ANG II-induced AGT augmentation in primary cultures of preglomerular VSMCs. We first demonstrated that these preglomerular VSMCs express renin, AGT, angiotensin-converting enzyme, and ANG II type 1 (AT1) receptors. Furthermore, incubation with ANG II (100 pmol/l for 24 h) increased AGT mRNA (1.42 ± 0.03, ratio to control) and protein (1.68 ± 0.05, ratio to control) expression levels, intracellular ANG II levels, and NF-κB activity. In contrast, the ANG II treatment did not alter AT1a and AT1b mRNA levels in the cells. Treatment with H-1152 (ROCK inhibitor, 10 nmol/l) and ROCK1 small interfering (si) RNA suppressed the ANG II-induced AGT augmentation and the upregulation and translocalization of p65 into nuclei. Functional studies showed that ROCK exerted a greater influence on afferent arteriole responses to ANG II in rats subjected to chronic ANG II infusions. These results indicate that ROCK is involved in NF-κB activation and the ROCK/NF-κB axis contributes to ANG II-induced AGT upregulation, leading to intracellular ANG II augmentation.


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