Formation of an F2-isoprostane in vascular smooth muscle cells by elevated glucose and growth factors

1996 ◽  
Vol 271 (1) ◽  
pp. H159-H165 ◽  
Author(s):  
R. Natarajan ◽  
L. Lanting ◽  
N. Gonzales ◽  
J. Nadler

Recently a series of non-cyclooxygenase-derived prostanoids were identified in vivo in humans and in animal models of free radical injury as products of free radical-catalyzed peroxidation of arachidonic acid. One of these, an F2-isoprostane, 8-epiprostaglandin F2 alpha (8-epi-PGF 2 alpha), is a potent renal vasoconstrictor and can increase vascular smooth muscle cell (VSMC) DNA synthesis. In the present study we have evaluated whether F2-isoprostanes play a role in diabetic vascular dysfunction by studying the formation of 8-epi-PGF2 alpha in porcine VSMC (PVSMC) cultured under hyperglycemic conditions. 8-Epi-PGF2 alpha levels were quantitated by a specific enzyme immunoassay. We also examined whether certain VSMC growth factors, such as angiotensin II, platelet-derived growth factor, and transforming growth factor-beta, could also regulate the formation of 8-epi-PGF2 alpha. We observed that PVSMC cultured under high glucose (HG) conditions produced significantly higher amounts of 8-epi-PGF2 alpha compared with normal glucose (NG) conditions (3.7 +/- 0.13 ng/10(6) cells in HG vs. 2.9 +/- 0.2 ng/10(6) cells in NG, P < 0.05). Furthermore, all three growth factors tested evoked significant dose-dependent formation of 8-epi-PGF2 alpha (ranging from 125 to 220% of control). These results suggest that 8-epi-PGF2 alpha formation, as a result of hyperglycemia or due to growth factor action, may lead to increased VSMC growth and contribute to the complications of diabetes and cardiovascular disease.

2007 ◽  
Vol 85 (5) ◽  
pp. 606-615 ◽  
Author(s):  
Dabin Pan ◽  
Junwei Yang ◽  
Fengxiang Lu ◽  
Di Xu ◽  
Lei Zhou ◽  
...  

PDGF-BB (Platelet-derived growth factor BB) and TGF-β1(transforming growth factor β1) are important growth factors in the modulation of vascular smooth muscle cell (VSMC) proliferation and PCNA (proliferating cell nuclear antigen) expression in VSMCs. PCNA expresses at a high level in proliferating cells. The present study aims to assess the effects of PDGF-BB-induced overexpression of TGF-β1 on PCNA in VSMCs. The downstream proteins of the TGF-β signalling system in VSMCs, including TGF-β type I receptor (ALK-5 in VSMCs), Smurf2, Smad2, pSmad2/3, Smad4, and Smad7, were also investigated. Our results revealed that PDGF-BB significantly increased the expressions of TGF-β1 and PCNA, and the increase in PCNA can be partially inhibited by neutralizing anti-TGF-β1 antibody. Furthermore, PDGF-BB increased the expression of ALK-5, Smurf2, pSmad2/3, and Smad4, but lowered the levels of Smad2 and Smad7; these alterations were partially restored by neutralizing anti-TGF-β1 antibody. These findings suggest that PDGF-BB promotes PCNA expression in VSMCs partially through TGF-β1 overexpression, and that the TGF-β signalling system involves the molecular mechanism of PDGF-BB in VSMCs.


Reproduction ◽  
2000 ◽  
pp. 85-91 ◽  
Author(s):  
S Hasthorpe ◽  
S Barbic ◽  
PJ Farmer ◽  
JM Hutson

At birth, the mouse gonocyte does not resume mitotic activity for several days in vivo but, in an in vitro clonogenic system, cell division commences soon after culture. Somatic testis cell underlays had potent inhibitory activity on gonocyte-derived colony formation (23 +/- 15% compared with 84 +/- 1% in controls; P = 0.0001) when added to cultures of gonocytes in vitro. A Sertoli cell line, TM4B, had an even more pronounced effect on gonocyte clonogenic capacity, with 1 +/- 1% compared with 72 +/- 17% colony formation in controls (P = 0.0003). Testis cells appeared to have a direct inhibitory effect since testis-conditioned medium did not show a significant reduction in the number of colonies. The observed reduction in colony formation with the testis cell underlay was not accounted for by decreased attachment of gonocytes as simultaneous addition of a single cell suspension of testis cells was still effective in significantly reducing colony number when compared with controls (P = 0.01). Therefore, the observed inhibition exerted by testis cells appears to be a consequence of decreased proliferation of gonocytes. Growth factors belonging to the transforming growth factor beta superfamily which are known to be expressed in testis, such as transforming growth factor beta and epidermal growth factor, did not exert any inhibitory action on gonocyte-derived colony formation when added together or alone. However, a shift to a smaller colony size occurred in the presence of transforming growth factor beta and transforming growth factor beta plus epidermal growth factor, indicating a reduction in colony cell proliferation. Evidence for the expression of the Mullerian inhibiting substance receptor on newborn gonocytes using in situ hybridization was inconclusive. This finding was in agreement with the lack of a direct action of Mullerian inhibiting substance on the formation of gonocyte-derived colonies in vitro. Leukaemia inhibitory factor, alone or in combination with forskolin, had neither an inhibitory nor an enhancing effect on gonocyte-derived colony formation. An in vitro clonogenic method to assay for the proliferation of gonocytes in the presence of specific growth factors, cell lines, testis cell underlays and cell suspensions was used to identify a somatic cell-mediated inhibitor which may be responsible for the inhibitory action on gonocyte proliferation in vivo shortly after birth.


2011 ◽  
Vol 392 (5) ◽  
Author(s):  
Johannes M. Nuessle ◽  
Klaudia Giehl ◽  
Rosa Herzog ◽  
Sylvia Stracke ◽  
Andre Menke

Abstract Neointimal formation in atheromatous blood vessels is associated with both growth factor-induced differentiation of smooth muscle cells and endothelial-to-mesenchymal transition. Transforming growth factor beta (TGFβ)-signaling is well known to play a critical role in the regulation of vessel remodeling as well as in atherosclerosis and restenosis. Here, we investigated the role of TGFβ1 and N-cadherin on the differentiation and migration of human vascular smooth muscle cells (VSMC). TGFβ1-treatment of cultured VSMC reduced their migratory activity as determined in cell migration assays. This reduced migration correlated with increased concentration of N-cadherin on mRNA and protein level. The TGFβ1-induced increase of N-cadherin was sensitive against pharmacological inhibition of the ALK5 TGFβ receptor and was accompanied by TGFβ1-induced expression of the transcription factor snail1. Activation of N-cadherin by using a HAV-containing peptide of N-cadherin also decreased the migration of VSMC. N-cadherin-mediated suppression of VSMC migration was associated with an increased activity of RhoA, which is activated by binding of the HAV peptide to N-cadherin. Our results demonstrate that TGFβ1 induces the differentiation of primary VSMC cells by Smad2/3-dependent up-regulation of the transcription factor snail1 and subsequently of N-cadherin, leading to inhibition of VSMC migration by RhoA-dependent modulation of the actin cytoskeleton.


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