scholarly journals Beta-type transforming growth factor specifies organizational behavior in vascular smooth muscle cell cultures.

1987 ◽  
Vol 105 (1) ◽  
pp. 465-471 ◽  
Author(s):  
R A Majack
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Organizational Behavior ◽  
Transforming Growth Factor ◽  
Cell Types ◽  
Cell Contact ◽  
Dependent Manner ◽  
Tgf Beta ◽  
The Hill

In culture, vascular smooth muscle cells (SMC) grow in a "hill-and-valley" (multilayered) pattern of organization. We have studied the growth, behavioral organization, and biosynthetic phenotype of rat aortic SMC exposed to purified platelet-derived growth regulatory molecules. We show that multilayered growth is not a constitutive feature of cultured SMC, and that beta-type transforming growth factor (TGF-beta) is the primary determinant of multilayered growth and the hill-and-valley pattern of organization diagnostic for SMC in culture. TGF-beta inhibited, in a dose-dependent manner, the serum- or platelet-derived growth factor-mediated proliferation of these cells in two-dimensional culture, but only when cells were plated at subconfluent densities. The ability of TGF-beta to inhibit SMC growth was inversely correlated to plating cell density. When SMC were plated at monolayer density (5 X 10(4) cells/cm2) to allow maximal cell-to-cell contact, TGF-beta potentiated cell growth. This differential response of SMC to TGF-beta may contribute to the hill-and-valley pattern of organization. Unlike its effect on other cell types, TGF-beta did not enhance the synthesis of fibronectin or its incorporation into the extracellular matrix. However, the synthesis of a number of other secreted proteins was altered by TGF-beta treatment. SMC treated with TGF-beta for 4 or 8 h secreted markedly enhanced amounts of an Mr 38,000-D protein doublet whose synthesis is known to be increased by heparin (another inhibitor of SMC growth), suggesting metabolic similarities between heparin- and TGF-beta-mediated SMC growth inhibition. The data suggest that TGF-beta may play an important and complex regulatory role in SMC proliferation and organization during development and after vascular injury.

EGF and TGF-beta regulate neutral endopeptidase expression in renal vascular smooth muscle cells

1997 ◽  
Vol 272 (6) ◽  
pp. C1836-C1843 ◽  
Author(s):  
P. L. Tharaux ◽  
A. Stefanski ◽  
S. Ledoux ◽  
J. M. Soleilhac ◽  
R. Ardaillou ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Transforming Growth Factor ◽  
Muscle Cells ◽  
Neutral Endopeptidase ◽  
Tgf Beta ◽  
Renal Vascular

We recently reported that neutral endopeptidase (NEP) expression on renal vascular smooth muscle cells (VSMC) was downregulated in the presence of serum. Here we examine the role of epidermal growth factor (EGF) and transforming growth factor-beta 1 (TGF-beta) in this downregulation and the consequences of the changes in NEP activity on their mitogenic effects. EGF inhibited NEP activity, whereas TGF-beta was stimulatory. Expression of the enzyme was studied by measuring the binding of [125I]RB-104, a specific NEP inhibitor, and the fluorescence intensity of NEP-labeled cells. Both parameters were decreased by EGF and were increased by TGF-beta. NEP mRNA expression in EGF-treated cells was reduced after 48 h. In contrast, it was increased in TGF-beta-treated cells. Interestingly, NEP inhibition influenced the mitogenic effect of EGF. Indeed, thiorphan, an NEP inhibitor, and an anti-NEP antibody decreased EGF-dependent [3H]thymidine incorporation and cell proliferation by approximately 50%. TGF-beta had no effect on VSMC growth. These results indicate that EGF but not TGF-beta participates in the downregulatory potency of serum on NEP expression in VSMC. They also demonstrate that the full effect of EGF on VSMC proliferation depends on intact NEP activity.

scholarly journals Role of the latent TGF-beta binding protein in the activation of latent TGF-beta by co-cultures of endothelial and smooth muscle cells.

1993 ◽  
Vol 120 (4) ◽  
pp. 995-1002 ◽  
Author(s):  
R Flaumenhaft ◽  
M Abe ◽  
Y Sato ◽  
K Miyazono ◽  
J Harpel ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Smooth Muscle Cells ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Binding Protein ◽  
Muscle Cells ◽  
Beta Activity ◽  
Dependent Manner ◽  
Tgf Beta

Transforming growth factor beta (TGF-beta) is released from cells in a latent form consisting of the mature growth factor associated with an aminoterminal propeptide and latent TGF-beta binding protein (LTBP). The endogenous activation of latent TGF-beta has been described in co-cultures of endothelial and smooth muscle cells. However, the mechanism of this activation remains unknown. Antibodies to native platelet LTBP and to a peptide fragment of LTBP inhibit in a dose-dependent manner the activation of latent TGF-beta normally observed when endothelial cells are cocultured with smooth muscle cells. Inhibition of latent TGF-beta activation was also observed when cells were co-cultured in the presence of an excess of free LTBP. These data represent the first demonstration of a function for the LTBP in the extracellular regulation of TGF-beta activity and indicate that LTBP participates in the activation of latent TGF-beta, perhaps by concentrating the latent growth factor on the cell surface where activation occurs.

scholarly journals Role of PDGF-A expression in the control of vascular smooth muscle cell growth by transforming growth factor-beta.

1990 ◽  
Vol 111 (1) ◽  
pp. 239-247 ◽  
Author(s):  
R A Majack ◽  
M W Majesky ◽  
L V Goodman
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Transforming Growth Factor Beta ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
De Novo ◽  
Tgf Beta ◽  
Gene And Protein Expression ◽  
Growth Factor Beta

Transforming growth factor-beta (TGF-beta) is a multifunctional regulatory peptide that can inhibit or promote the proliferation of cultured vascular smooth muscle cells (SMCs), depending on cell density (Majack, R. A. 1987. J. Cell Biol. 105:465-471). In this study, we have examined the mechanisms underlying the growth-promoting effects of TGF-beta in confluent SMC cultures. In mitogenesis assays using confluent cells, TGF-beta was found to potentiate the stimulatory effects of serum, PDGF, and basic fibroblast growth factor (bFGF), and was shown to act individually as a mitogen for SMC. In gene and protein expression experiments, TGF-beta was found to regulate the expression of PDGF-A and thrombospondin, two potential mediators of SMC proliferative events. The induction of thrombospondin protein and mRNA was density-dependent, delayed relative to its induction by PDGF and, based on cycloheximide experiments, appeared to depend on the de novo synthesis of an intermediary protein (probably PDGF-A). The relationship between PDGF-A expression and TGF-beta-mediated mitogenesis was investigated, and it was determined that a PDGF-like activity (probably PDGF-A) was the biological mediator of the growth-stimulatory effects of TGF-beta on confluent SMC. The effects of purified homodimers of PDGF-A on SMC replication were investigated, and it was determined that PDGF-AA was mitogenic for cultured SMC, particularly when used in combination with other growth factors such as bFGF and PDGF-BB. The data suggest several molecular mechanisms that may account for the ability of TGF-beta to promote the growth of confluent SMC in culture.

scholarly journals Tamoxifen decreases the rate of proliferation of rat vascular smooth-muscle cells in culture by inducing production of transforming growth factor β

1993 ◽  
Vol 294 (1) ◽  
pp. 109-112 ◽  
Author(s):  
D J Grainger ◽  
P L Weissberg ◽  
J C Metcalfe
Keyword(s):  
Cell Cycle ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Transforming Growth Factor ◽  
Beta Activity ◽  
Tgf Beta ◽  
M Phase

Tamoxifen selectively and reversibly decreased the rate of proliferation of adult rat aortic vascular smooth-muscle cells (VSMCs). Half-maximal inhibition of proliferation occurred at 2-5 microM tamoxifen for VSMCs and at > 50 microM for adventitial fibroblasts. The cell cycle time for all the VSMCs in the population was increased from 35 +/- 2 h to 54 +/- 4 h in the presence of 33 microM tamoxifen. Tamoxifen did not affect the time of entry into DNA synthesis, but delayed arrival at mitosis by > 24 h. It therefore extended the duration of the G2-to-M phase of the cell cycle. However, the rate of proliferation of VSMCs was not decreased by tamoxifen (at concentrations up to 50 microM) in the presence of neutralizing antibody to transforming growth factor beta (TGF-beta). The level of mRNA for TGF-beta 1 in VSMCs was strongly induced by 10 microM tamoxifen, and TGF-beta activity in conditioned medium from tamoxifen-treated cells was more than 50-fold higher than from control cells. Tamoxifen therefore extended the G2-to-M phase of the cell cycle in VSMCs by increasing TGF-beta activity in the culture.

Abstract 297: Cyclic GMP Reduces Vascular Smooth Muscle Migration through Inhibition of TGF-ß1/Smad Signaling

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Jackson R Vuncannon ◽  
Joshua D Stone ◽  
Danielle N Martin ◽  
Chintamani N Joshi ◽  
Shaquria P Adderley ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Cyclic Gmp ◽  
Transforming Growth Factor ◽  
Soluble Guanylate Cyclase ◽  
Sandwich Elisa ◽  
Cell Lysates ◽  
Tgf Β1

Abnormal vascular smooth muscle (VSM) growth remains an elemental foundation of vasculoproliferative disorders including atherosclerosis and restenosis. Many second messenger, cytokine, and growth factor signals mediate control of VSM growth, and among these is transforming growth factor (TGF)-β1, a pluripotent cytokine with wide-ranging yet often opposite effects in VSM. Cyclic nucleotide signaling also exerts powerful growth control of VSM, and our previous work has helped establish a biological link between cyclic GMP and TGF-β1 in injured carotid arteries. The current study characterized the influence of cyclic GMP on TGF-β1 and its receptor-activated Smad3 in rat primary VSM cells. The heme-dependent soluble guanylate cyclase (sGC) stimulator BAY 41-2272 (BAY41) significantly increased cyclic GMP and site-specific phosphorylation of vasodilator-activated serum phosphoprotein (VASP) in manner indicative of active protein kinase G (PKG) and PKA signaling. Recombinant TGF-β1 (10 ng/ml) significantly stimulated phospho-Smad3 (Ser 423/425 ) and decreased inhibitory Smad7 in VSM cell homogenates, and using flow cytometry significantly increased cells in G 2 /M and expression of cyclins D and E and Cdk2 and Cdk4 while decreasing expression of inhibitory p21 and p27 after 24 hours compared to vehicle controls. TGF-β1 also significantly increased cell numbers compared to controls after 48 hours, thus confirming growth promoting capacities of TGF-β1 in VSM. In cell lysates double-sandwich ELISA revealed that BAY41 significantly reduces total and active TGF-β1, and Western analyses showed it significantly decreases total and phospho-Smad3 Ser423/425 expression and reduces MMP-2 and MMP-9 expression and activity (via column zymography) in both cell lysates and conditioned media after 1 and 48 hours. BAY41 also significantly reduced serum- and PDGF-stimulated cell migration between 6 and 18 hours using an in vitro scrape injury and a transwell assay. In comparison, inclusive effects of BAY41 were replicated by its prototype YC-1 and by the heme-independent sGC activator BAY 60-2770. These data clearly support growth protective capacities of cGMP in VSM and propose it operates through attenuation of TGF-β1/Smad3 signaling.

scholarly journals TGF-β suppresses the upregulation of MMP-2 by vascular smooth muscle cells in response to PDGF-BB

2010 ◽  
Vol 298 (1) ◽  
pp. C191-C201 ◽  
Author(s):  
George M. Risinger ◽  
Dawn L. Updike ◽  
Elizabeth C. Bullen ◽  
James J. Tomasek ◽  
Eric W. Howard
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Transforming Growth Factor ◽  
Focal Adhesions ◽  
Muscle Cells ◽  
Threshold Level ◽  
Inhibitory Signaling

During platelet-derived growth factor (PDGF)-BB-mediated recruitment to neovascular sprouts, vascular smooth muscle cells (VSMCs) dedifferentiate from a contractile to a migratory phenotype. This involves the downregulation of contractile markers such as smooth muscle (SM) α-actin and the upregulation of promigration genes such as matrix metalloproteinase (MMP)-2. The regulation of MMP-2 in response to PDGF-BB is complex and involves both stimulatory and inhibitory signaling pathways, resulting in a significant delay in upregulation. Here, we provide evidence that the delay in MMP-2 upregulation may be due to the autocrine expression and activation of transforming growth factor (TGF)-β, which is known to promote the contractile phenotype in VSMCs. Whereas PDGF-BB could induce the loss of stress fibers and focal adhesions, TGF-β was able to block or reverse this transition to a noncontractile state. TGF-β did not, however, suppress early signaling events stimulated by PDGF-BB. Over time, though PDGF-BB induced increased TGF-β1 levels, it suppressed TGF-β2 and TGF-β3 expression, leading to a net decrease in the total TGF-β pool, resulting in the upregulation of MMP-2. Together, these findings indicate that MMP-2 expression is suppressed by a threshold level of active TGF-β, which in turn promotes a contractile VSMC phenotype that prevents the upregulation of MMP-2.

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