14,15-Epoxyeicosatrienoic acid inhibits prostaglandin E2 production in vascular smooth muscle cells

1998 ◽  
Vol 275 (6) ◽  
pp. H2113-H2121 ◽  
Author(s):  
Xiang Fang ◽  
Steven A. Moore ◽  
Lynn L. Stoll ◽  
Gretchen Rich ◽  
Terry L. Kaduce ◽  
...  

14,15-Epoxyeicosatrienoic acid (EET), a cytochrome P-450 epoxygenase product of arachidonic acid (AA), reduced PGE2 formation by 40–75% in porcine aortic and murine brain microvascular smooth muscle cells. The inhibition was reversed 6–10 h after removal of 14,15-EET from the medium and was regioisomeric specific; 8,9-EET produced a smaller effect, whereas 11,12- and 5,6-EET were ineffective. Although the cells converted 14,15-EET to 14,15-dihydroxyeicosatrienoic acid (14,15-DHET), 14,15-DHET did not inhibit PGE2formation, and the 14,15-EET-induced inhibition was potentiated by 4-phenylchalcone oxide, an epoxide hydrolase inhibitor. The inhibition occurred when substrate amounts of AA were used and was not accompanied by enhanced production of other PGs, suggesting an effect on PGH synthase; however, in murine cells, 14,15-EET did not reduce PGH synthase mRNA or protein. Moreover, the 14,15-EET-induced decrease in PGE2 production was overcome by increasing the concentration of AA, but not oleic acid (which is not a substrate for PGH synthase). These findings suggest that 14,15-EET competitively inhibits PGH synthase activity in vascular smooth muscle cells. The 14,15-EET-induced inhibition of PGE2 production resulted in potentiation of platelet-derived growth factor-induced smooth muscle cell proliferation, suggesting that the competitive inhibition of PGH synthase by 14,15-EET can affect growth responses in smooth muscle cells.

1989 ◽  
Vol 257 (6) ◽  
pp. H1755-H1765 ◽  
Author(s):  
G. K. Owens

A long-term objective of my laboratory has been to understand the mechanisms that regulate both normal and developmental growth of vascular smooth muscle as well as the accelerated growth of smooth muscle that occurs in atherosclerotic lesions or arteries of hypertensive patients and animals. Previous studies in this and other laboratories have demonstrated that smooth muscle cells are capable of two distinct growth responses in vivo, depending on the nature of the growth stimulus. Smooth muscle cell growth in large vessels of chronically hypertensive animals appears to occur primarily by enlargement of preexisting cells (i.e., cellular hypertrophy) with little or no cell proliferation (hyperplasia) and is accompanied by development of polyploidy in a large fraction of the cells. In contrast, in experimental injury models of atherogenesis, or after induction of severe acute hypertension, aortic smooth muscle cells undergo a classic proliferative response. This lecture focuses on possible control mechanisms for hypertrophy of vascular smooth muscle, with particular emphasis on examination of the possible role of contractile agonists as hypertrophic agents, exploration of how this process differs from cellular hyperplasia, discussion of the possible mechanisms for formation of polyploid cells, and examination of the role of mechanical factors in growth regulation of vascular smooth muscle cells.


1997 ◽  
Vol 131 (2) ◽  
pp. 219-228 ◽  
Author(s):  
Jun Saito ◽  
Takashi Terano ◽  
Aizan Hirai ◽  
Tatsuya Shiina ◽  
Yasushi Tamura ◽  
...  

1989 ◽  
Vol 61 (03) ◽  
pp. 517-521 ◽  
Author(s):  
Walter E Laug ◽  
Ruedi Aebersold ◽  
Ambrose Jong ◽  
Willian Rideout ◽  
Barbara L Bergman ◽  
...  

SummaryLarge arteries have a natural resistance to tumor cell invasion thought to be due to the production of protease inhibitors. Vascular smooth muscle cells (VSMC) representing the major cellular part of arteries were isolated from human aortas and grown in tissue culture. These cells were found to produce large amounts of inhibitors of plasminogen activators (PA). Fractionation of VSMC-conditioned medium by heparin-affigel chromatography separated three immunologically and functionally distinct PA inhibitors (PAI), namely PAI-1, PAI-2 and protease-nexin I. The three inhibitors were characterized by functional assays and immunoblotting. PA inhibitor 2 (PAI-2) had little affinity for heparin, whereas PA inhibitor 1 (PAI-l) bound to heparin and was eluted from the column at NaCl concentrations of 0. 1 to 0.35 M. Protease-nexin I, eluted at NaCl concentrations of 0.5 M and higher. Most of the PAI-1 was present in the latent, inactive form. PAI-1 was further purified by ion exchange chromatography on a Mono-Q column. Partial sequencing of the purified PAI-1 confirmed its nature by matching completely with the sequence deduced from the cDNA nucleotide sequence of endothelial cell PAI-1. Thus, human VSMC produce all three presently known PAI and these can be separated in a single heparin affinity purification step.


1995 ◽  
Vol 74 (03) ◽  
pp. 980-986 ◽  
Author(s):  
Valérie B Schini-Kerth ◽  
Beate Fißithaler ◽  
Thomas T Andersen ◽  
John W Fenton ◽  
Paul M Vanhoutte ◽  
...  

SummaryProteolytically active forms of thrombin (α- and γ-thrombin) and thrombin receptor peptides inhibited the release of nitrite, a stable endproduct of nitric oxide, evoked by interleukin-1 β(IL-1 β) in cultured vascular smooth muscle cells while proteolytically inactive forms [D-Phe-Pro-Arg chloromethyl ketone-α-thrombin (PPACK-α- thrombin) and diisopropylphosphoryl-α-thrombin (DIP-α-thrombin)] had either no or only minimal inhibitory effects. Under bioassay conditions, perfusates from columns containing IL-1 β-activated vascular smooth muscle cells or cells treated with IL-1βplus PPACK-α-thrombin relaxed detector blood vessels. These relaxations were abolished by the inhibitor of nitric oxide synthesis, NG-nitro-L arginine. No relaxations were obtained with untreated cells or IL-1 β-treated cells in the presence of α-thrombin. The expression of inducible nitric oxide synthase mRNA and protein in vascular smooth muscle cells by IL-1 β was impaired by α-thrombin. These results demonstrate that thrombin regulates the expression of the inducible nitric oxide synthase at a transcriptional level via the proteolytic activation of the thrombin receptor in vascular smooth muscle cells


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