Published online before print August 11, 2003, doi: 10.1161/01.CIR.0000085211.97972.2C
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
(Circulation. 2003;108:1015.)
© 2003 American Heart Association, Inc.
Basic Science Reports |
Dual Functionality of Cyclooxygenase-2 as a Regulator of Tumor Necrosis Factor–Mediated G1 Shortening and Nitric Oxide–Mediated Inhibition of Vascular Smooth Muscle Cell Proliferation
From the Department of Pharmacology, New York Medical College, Valhalla, NY.
Correspondence to Dr Nicholas R. Ferreri, New York Medical College, Department of Pharmacology, Valhalla, NY 10595. E-mail nick_ferreri{at}nymc.edu
Received November 11, 2002; revision received April 22, 2003; accepted May 5, 2003.
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Background— Cyclooxygenase (COX)-2 contributes to vascular smooth muscle cell (VSMC) proliferation induced by tumor necrosis factor (TNF) and angiotensin II. The present study demonstrates, however, that depending on prevailing conditions, COX-2–derived prostanoids may also inhibit VSMC proliferation.
Methods and Results— TNF-
stimulated proliferation of VSMCs by shortening the G1 phase of the cell cycle. This effect was abolished by NS-398, a selective COX-2 inhibitor. Addition of TNF did not affect the protein-to-DNA ratio, measured by flow cytometry, suggesting that TNF does not induce VSMC hypertrophy. Inhibition of nitric oxide synthase (NOS) activity attenuated TNF-mediated increases in prostaglandin (PG) I2 synthesis, whereas thromboxane (TX) A2 production and COX-2 protein expression were unaffected. Moreover, inhibition of NOS activity increased TNF-mediated proliferation by 
23%. Thus, NO preferentially stimulates PGI2 production, suggesting that production of NO by VSMCs challenged with TNF limits the ability of the cytokine to increase proliferation. NO donors increased COX-2 protein expression and PGI2 synthesis, had no effect on TXA2 production, and decreased cell numbers by 50%, indicating that expression of COX-2 per se might not be sufficient to support proliferation. The effects of NO donors were prevented when COX-2 activity was inhibited with NS-398.
Conclusions— The COX-2–dependent proliferative response of VSMCs to TNF was modulated in an NO-dependent manner, and PGI2 derived from COX-2 might contribute to the antiproliferative effect of NO donors.
Key Words: prostaglandins • muscle, smooth • nitric oxide • thromboxane
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
We recently demonstrated that a cyclooxygenase (COX)–2-dependent mechanism was required for vascular smooth muscle cell (VSMC) proliferation in response to either tumor necrosis factor (TNF) or angiotensin II (Ang II).1 This mechanism might contribute to VSMC hyperplasia associated with vascular injury or pathophysiological conditions in which elevated levels of either TNF or Ang II are evident. VSMCs respond to growth factors by several different mechanisms, including hyperplasia, hypertrophy, and apoptosis. Hyperplasia is an important component of hypertension, atherosclerosis, and restenosis. For instance, significant increases in proliferation were observed in the media of blood vessels obtained from animals with chronic hypertension.2 TNF has been detected in restenotic lesions, intimal VSMCs and plaques of atherosclerotic arteries, and models of transplantation-associated atherosclerosis, and has been associated with VSMC proliferation in a rabbit balloon-injury model.3,4
TNF is produced by VSMCs and increases expression of COX-2 and inducible nitric oxide synthase (NOS).1,4,5 COX-2 is the predominant isoform utilized for the synthesis of prostaglandin (PG) I2 and thromboxane (TX) A2 in VSMCs challenged with either TNF or Ang II.1 Increased levels of NO inhibit VSMC proliferation.6 In macrophages, however, activation of COX-2 by cytokines downregulated NO-mediated apoptosis.7 In the present study, we demonstrate for the first time that TNF increases VSMC hyperplasia in a COX-2–dependent manner by shortening the G1 phase of the cell cycle. We also establish the antiproliferative effects of COX-2 activation in the presence of NO, a reflection of the stimulus-dependent dual functionality of COX-2 on VSMC growth.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Animals
Male Sprague-Dawley rats (Charles River Laboratory, Wilmington, Mass) weighing 100 to 115 g were maintained on standard rat chow (Ralston-Purina Co) and given tap water ad libitum.
Reagents
TNF was purchased from Pepro Tech Inc. NS-398 was purchased from Biomol Research Laboratory. Aminoguanidine (AG), propidium iodide, detanonoate (DN), sodium nitroprusside (SNP), sulforhodamine 101, RNase A, the DNA fluorochrome 4',6-diamidino-2-phenylindole (DAPI), and monoclonal anti–ß-actin (clone AC-15) were purchased from Sigma. Papanonoate, monoclonal anti–COX-1 (No. 160110), and polyclonal anti–COX-2 (No. 160126) were purchased from Cayman. 2,3-Diaminonaphthalene was purchased from Molecular Probes, and anti-p27kip1 (sc-1641) and anti-cyclin D1 (HD11) were purchased from Santa Cruz.
VSMCs From Thoracic Aortas
Cultures of VSMCs were established as previously described.1
Western Blot Analysis of COX-2, COX-1, p27kip, Cyclin D1, and ß-Actin Proteins
Expression of COX proteins was determined as previously described.1 Analyses of cyclin D1 and p27kip1 were done after cells were lysed in ice-cold RIPA buffer. Lysates were centrifuged at 14 000g and 4°C for 15 minutes, and the supernatant was separated on a sodium dodecyl sulfate–10% polyacrylamide gel.
Enzyme-Linked Immunosorbent Assay
Analysis of 6-keto-PGF1 and TXB2 levels was performed on cell-free supernatants with commercially available kits (Neogen) as previously described.1
Nitrite Assay
Quantification of nitrite/nitrate levels was determined by a fluorometric method based on the reaction of nitrite with 2,3-diaminonaphthalene to form the fluorescent product 1-(H)-naphthotriazole.8
Analysis of Cell Numbers
Cells were seeded at 20 000 per well in 96-well plates, left quiescent for 24 hours in Dulbecco’s modified Eagle’s medium/Ham’s F12 medium containing 0.5% fetal bovine serum, and then challenged. Cell number was determined with a proliferation assay (CellTiter), and absorbance was recorded at 490 nm (Promega).
Analysis of Cell Cycle
Cell cycle distribution was determined by staining cellular DNA with propidium iodide and measuring the fluorescence intensity by laser scanning cytometry (CompuCyte).9 In brief, cells were fixed, permeabilized with ethanol, and stained with a solution of propidium iodide (5 µg/mL) containing 0.1% RNase A. Cells were illuminated with a 488-nm argon-ion laser; green (530±20 nm) and red (>590 nm) fluorescence was measured by separate photomultipliers. At least 2000 cells were measured per sample, and the relative proportion of cells in the G1, S, or G2/M phases was estimated by deconvolution of the cellular DNA content-frequency histograms. For normalization of cell cycle data, the percentages of cells in the S and G2/M phases in the control cells were combined and considered to be 100%; the changes in S and G2/M phases in the treated cells were then analyzed as the percent difference compared with control.
Analysis of Cellular Protein-to-DNA Ratio
Cellular DNA and protein contents were determined after the samples were stained with DAPI (1 µg/mL) and sulforhodamine 101 (20 µg/mL), respectively. Cellular blue (490±20 nm) and red (>590 nm) fluorescence was measured with a flow cytometer (EPICS Elite ESP, Beckman-Coulter). Cells (10 000) were measured, and the ratio of intensity of the red fluorescence of sulforhodamine 101 to that of the blue fluorescence of DAPI was calculated to represent the protein-to-DNA ratio.
Statistical Analysis
The differences between control and treated VSMCs were compared by Student’s t test and, in instances where multiple comparisons were made, a 1-way ANOVA, followed by a Bonferroni post hoc test; probability values 
0.05 were considered statistically significant.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
TNF Shortens G1 Phase Duration
TNF increases VSMC proliferation in a COX-2–dependent manner.1 The effect of TNF on cell cycle distribution was measured by laser scanning cytometry. Treatment of VSMCs for 20 hours with TNF, in the absence of serum, shortened the G1 phase, which was correlated with a 50% increase in the percentage of cells in the S and G2/M phases (Figure 1). Addition of NS-398 did not affect the percentage of unstimulated cells (control) in the S and G2/M phases but prevented the effects of TNF on cell cycle progression. The increased percentage of cells in the S and G2/M phases preceded TNF-mediated increases in cell number, consistent with the notion that COX-2 induction by TNF contributes to a hyperplastic growth response of VSMCs. Indeed, significant increases in cell numbers were observed 48 hours after VSMCs were exposed to TNF in the absence of serum (Figure 2). It is important to note that TNF increased cell numbers in the absence of serum, suggesting that TNF increases VSMC hyperplasia even in the absence of growth factors that are present in serum (Figure 2). Moreover, proliferation was facilitated by the combination of serum and TNF (Figure 2). Because the growth response of VSMCs to autacoids might include hyperplasia or hypertrophy, the protein-to-DNA ratio was assessed to establish whether there was a hypertrophic response to TNF. The protein-to-DNA ratio did not change after exposure to TNF, suggesting that this cytokine did not induce VSMC hypertrophy (Figure 2, insert). Collectively, these data indicate that TNF increases VSMC hyperplasia by shortening the G1 phase in a COX-2–dependent manner.
|
|
Effects of TNF on p27kip1 and Cyclin D1 Expression
Proteins involved in cell cycle regulation might contribute to a COX-2–dependent growth mechanism. An increase in cyclin D1 and a concomitant decrease in p27kip1 were observed when VSMCs were exposed to TNF for 8 and 24 hours (Figure 3). These data support the observations regarding cell cycle progression and raise the possibility that COX-2 increases VSMC hyperplasia by way of a mechanism that involves cyclin D1, which promotes cell cycle progression in a p27kip1-dependent manner.
|
Regulation of COX-2–Derived Prostanoid Production by TNF-Mediated NO Synthesis
Increases in VSMC PGI2 and TXA2 synthesis are COX-2 dependent.1 Nitrite levels increased 3.5-fold (control, 5.26±0.37 versus TNF, 18.33±0.66 pmol/µg protein; P<0.001) after treatment with TNF for 24 hours and were abolished by addition of AG (data not shown). Inhibition of NO production had a differential effect on COX-2–derived prostanoid production. The levels of 6-keto-PGF1 increased 4-fold when VSMCs were challenged with TNF for 24 hours (Figure 4). Basal levels of 6-keto-PGF1 were not affected by treatment with AG; however, NOS inhibition at 24 hours was associated with significantly attenuated levels of 6-keto-PGF1 induced by TNF (Figure 4). Challenge with TNF for 24 hours also increased TXB2 levels; however, pretreatment with AG had no effect on TNF-induced TXB2 levels (Figure 4). Expression of COX-1 and COX-2 proteins was not affected when NO synthesis was inhibited (Figure 5), suggesting that the differential effects of NO might be related to an effect on COX-2 activity and/or terminal prostanoid synthases present in VSMCs. Thus, TNF-mediated increases in COX-2 expression and TXA2 synthesis occur via an NO-independent mechanism, whereas COX-2–dependent PGI2 synthesis is NO dependent.
|
|
Effects of NO Donors on Prostanoid Production
Addition of papanonoate for 24 hours increased PGI2 synthesis 5-fold but had no effect on TXA2 synthesis (Figure 6). Similar results were obtained when levels were measured after addition of SNP (50 µmol/L) for 8 hours, because 6-keto-PGF1 levels increased 1.7-fold (control, 217±31 vs 50 µmol/L SNP, 387±83 pg 6-keto PGF1/µg protein; P<0.01). In contrast, SNP had no effect on TXA2 synthesis (control, 13.5±1.7 vs 50 µmol/L SNP, 13±2.3 pg TXB2/µg protein; P>0.05). These data are in accord with those obtained with TNF and demonstrate that NO donors selectively increase VSMC PGI2 synthesis.
|
Functional Implications of COX-2–NO Interactions on VSMC Proliferation
Because AG attenuated TNF-mediated PGI2 synthesis, we tested the hypothesis that a reduction in the levels of an antiproliferative prostanoid (ie, PGI2) might affect TNF-mediated VSMC proliferation. Indeed, the proliferative response to TNF increased by an additional 23% when VSMCs were treated for 48 hours with TNF in the presence of AG (Figure 7). These data suggest that NO, produced in response to challenge with TNF, opposes TNF-mediated, COX-2–dependent proliferation of VSMCs. Addition of DN (1 mmol/L) or SNP (50 µmol/L) increased COX-2 protein expression and decreased cell number (Figure 8). COX-1 protein expression was not affected, supporting a COX-2–dependent regulation of proliferation by NO donors. Moreover, the data are consistent with an antiproliferative effect of NO on VSMCs that is mediated by PGI2 derived from COX-2. The data also suggest that increased COX-2 expression after challenge with an NO donor is not sufficient to support a proliferative response of VSMCs in the absence of a mitogenic stimulus and/or an increase in TXA2 synthesis.
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
We demonstrate that TNF induces VSMC hyperplasia by shortening the G1 phase of the cell cycle in a COX-2–dependent manner. The increased percentage of TNF-treated cells in the S and G2/M phases was abolished when COX-2 activity was inhibited. Treatment with TNF increased cyclin D1 and decreased p27kip1expression, regulators of cell cycle progression. Furthermore, a decreased duration of G1 preceded the increase in cell numbers observed after treatment with TNF. Thus, progression through the G1 phase in VSMCs is dependent on TNF-dependent signals, presumably before commitment to entrance into the S phase can be achieved. Although G1 shortening is COX-2 dependent, elevation of COX-2 expression per se is not sufficient to support VSMC proliferation, because NO donors, which also increase COX-2, caused a decrease in cell number. Because TNF-mediated increases in PGI2 and TXA2 synthesis are COX-2 dependent,1 the combination of COX-2-derived TXA2 synthesis and a TNF-dependent signal might be required for cell cycle progression. In the absence of these signals, vis-à-vis an increase in COX-2 expression and PGI2 synthesis, a COX-2–dependent decrease in VSMC cell number was observed (Figure 9). COX-2–dependent increases in PGI2 synthesis in response to TNF were NO dependent, whereas COX-2–dependent increases in TXA2 synthesis were NO independent. In addition, NO donors increased COX-2, but not COX-1, protein expression and increased PGI2 synthesis without affecting TXA2 production. COX-2–dependent proliferation of VSMCs in response to TNF was increased further when NO-mediated increases in PGI2 synthesis were attenuated after inhibition of NOS activity. These data suggest that the high levels of PGI2 produced when VSMCs were exposed to TNF act to antagonize the ability of TNF to drive cells through the cell cycle.
|
TNF-mediated proliferation and migration of VSMCs might contribute importantly to the development and progression of vascular disease. For instance, plasma TNF concentrations have been associated with early atherosclerosis and are correlated with metabolic and cellular changes considered important for vascular remodeling.10 The presence of TNF also was detected in models of transplantation-associated atherosclerosis and associated with VSMC proliferation.4 Moreover, inhibition of TNF with a soluble TNF receptor reagent inhibited acute coronary neointimal formation in a model of coronary-graft atherosclerosis.11 In VSMCs, Ang II is known to induce hypertrophy in the absence of serum and to induce hyperplasia in the presence of serum. We demonstrate that TNF does not induce VSMC hypertrophy in the absence or presence of serum.
The mechanisms by which TNF increases VSMC proliferation are not well understood; however, recent studies indicate that TNF increases expression of early growth-response factor-1 and extracellular signal–regulated kinases 1 and 2, pathways known to participate in growth.12,13 We previously demonstrated that mitogen-activated protein kinase inhibition prevented TNF-mediated COX-2 mRNA accumulation and protein expression in VSMCs.1 Although the exact contribution between proximal (early growth-response factor-1 and extracellular signal–regulated kinases 1 and 2) and distal (COX-2) products of TNF-mediated gene transcription on VSMC proliferation is not clear, these pathways might complement each other.
Previous studies demonstrated that NO modulates the catalytic activities of the ferriheme enzymes prostacyclin synthase and thromboxane synthase.14 Moreover, NO might favor a molecular process that activates prostacyclin synthase or protects it from "suicide" inactivation.15,16 The present study demonstrates that PGI2 production in VSMCs was partially NO dependent. In addition, NO donors selectively increased PGI2 synthesis without affecting TXA2 production. Previous studies have identified PGI2 as a prostanoid with antiproliferative properties17 and TXA2 as a comitogen for VSMCs.18,19 Thus, the increased proliferation of VSMCs after NOS inhibition might reflect removal of the antiproliferative effects of PGI2. Furthermore, the preferential inhibition of PGI2 synthesis by AG might have shifted the balance between PGI2 and TXA2 toward the growth-promoting actions of TXA2. Thus, a balance of PGI2 and TXA2 might be critical to VSMC hyperplasia. These data support the finding that the proliferative response of VSMCs to TNF increased when NOS activity was blocked and suggest that NO might be downregulating TNF-mediated VSMC proliferation via a PGI2-dependent mechanism. Although most TXA2 is generated by platelet-derived COX-1 in in vivo balloon-injury models,20 for example, significant amounts of TXA2 are produced by VSMCs after appropriate activation of COX-2.1 Thus, COX-2–derived TXA2 synthesis in the microenvironment of VSMCs might have effects on cell growth that are independent of TXA2 present in plasma, which is derived from platelet COX-1. Stimulation of COX-2–mediated TXA2 or PGI2 synthesis might promote or inhibit VSMC proliferation, respectively. These opposing actions suggest that coinduction of the COX and NOS systems might limit the extent of cell proliferation or death. For instance, our data indicate that when both systems are activated, inhibition of cytokine-induced NO production attenuates the antiproliferative response of NO in VSMCs.
NO has been shown to affect VSMC growth and apoptosis by several different mechanisms. NO induces apoptosis in several different cell types by increasing expression of p53, Bcl-2, and other proteins,21 and upregulation of CPP32, a member of the caspase/interleukin-1ß converting enzyme protease family, has been linked to NO-mediated apoptosis in VSMCs.22 The significance of these observations is accentuated by the finding that generation of NO, which leads to apoptosis in VSMCs, contributes to the process of vascular remodeling.23 The interactions of COX and NO pathways in VSMCs might modulate these events. For instance, NO donors have been shown to attenuate cell cycle progression through the S phase by targeting ribonucleotide reductase.6 Moreover, inhibition of VSMC proliferation in the G1 phase by cytokine-induced NOS has been shown to be dependent on cGMP-mediated activation of cAMP-dependent protein kinase A.24 This suggests that there is cGMP/cAMP-independent and -dependent regulation of VSMC proliferation in response to NO. PGI2 has been shown to increase cAMP production in human VSMCs and accordingly, might inhibit cell cycle progression.25 Such an interaction suggests that in the absence of TNF, COX-2 induction by NO donors increases cAMP levels by a preferential effect on PGI2 synthesis. However, in the presence of TNF, a COX-2–dependent shortening of G1 results in VSMC proliferation.
VSMC growth might be a pathophysiological response to diseases like hypertension and arteriosclerosis,26,27 and NO can influence net effects on proliferation.28 The role of COX-2 in the dysregulated proliferation of several tumor cell types has recently been demonstrated.29,30 Moreover, interactions between COX-2 and NO that affect growth have been noted in chondrocyte cell death leading to osteoarthritis, because selective inhibition of COX-2 by NS-398 blocked SNP-induced chondrocyte apoptosis.31 Similar interactions might influence the proliferation of VSMCs because inhibition of COX-2 activity prevented NO-mediated cell death. Furthermore, inhibition of NOS activity in the present study enhanced the COX-2–dependent proliferative response to TNF. Such a mechanism might be relevant to the regulation of hyperplasia and apoptosis in diseases such as atherosclerosis and hypertension.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Young W, Mahboubi K, Haider A, et al. Cyclooxygenase-2 is required for tumor necrosis factor-alpha- and angiotensin II–mediated proliferation of vascular smooth muscle cells. Circ Res. 2000; 86: 906–914.
2. Kato H, Hou J, Chobanian AV, et al. Effects of angiotensin II infusion and inhibition of nitric oxide synthase on the rat aorta. Hypertension. 1996; 28: 153–158.
3. Jovinge S, Hultgardh-Nilsson A, Regnstrom J, et al. Tumor necrosis factor-alpha activates smooth muscle cell migration in culture and is expressed in the balloon-injured rat aorta. Arterioscler Thromb Vasc Biol. 1997; 17: 490–497.
4. Tanaka H, Swanson SJ, Sukhova G, et al. Smooth muscle cells of the coronary arterial tunica media express tumor necrosis factor-alpha and proliferate during acute rejection of rabbit cardiac allografts. Am J Pathol. 1995; 147: 617–626.[Abstract]
5. Newman WH, Zhang LM, Leeper-Woodford SK, et al. Human blood vessels release tumor necrosis factor-alpha from a smooth muscle cell source. Crit Care Med. 1996; 24: 294–297.[CrossRef][Medline] [Order article via Infotrieve]
6. Sarkar R, Gordon D, Stanley JC, et al. Dual cell cycle–specific mechanisms mediate the antimitogenic effects of nitric oxide in vascular smooth muscle cells. J Hypertens. 1997; 15: 275–283.[CrossRef][Medline] [Order article via Infotrieve]
7. von Knethen A, Callsen D, Brune B. NF-kappaB and AP-1 activation by nitric oxide attenuated apoptotic cell death in RAW 264.7 macrophages. Mol Biol Cell. 1999; 10: 361–372.
8. Misko TP, Schilling RJ, Salvemini D, et al. A fluorometric assay for the measurement of nitrite in biological samples. Anal Biochem. 1993; 214: 11–16.[CrossRef][Medline] [Order article via Infotrieve]
9. Darzynkiewicz Z, Bedner E, Li X, et al. Laser-scanning cytometry: a new instrumentation with many applications. Exp Cell Res. 1999; 249: 1–12.[CrossRef][Medline] [Order article via Infotrieve]
10. Skoog T, Dichtl W, Boquist S, et al. Plasma tumour necrosis factor-alpha and early carotid atherosclerosis in healthy middle-aged men. Eur Heart J. 2002; 23: 376–383.
11. Rayment NB, Moss E, Faulkner L, et al. Synthesis of TNF-alpha and TGF-beta mRNA in the different micro-environments within atheromatous plaques. Cardiovasc Res. 1996; 32: 1123–1130.
12. Fu M, Zhang J, Lin Y, et al. Early growth response factor-1 is a critical transcriptional mediator of peroxisome proliferator–activated receptor-gamma 1 gene expression in human aortic smooth muscle cells. J Biol Chem. 2002; 277: 26808–26814.
13. Silverman ES, Collins T. Pathways of Egr-1–mediated gene transcription in vascular biology. Am J Pathol. 1999; 154: 665–670.
14. Wade ML, Fitzpatrick FA. Nitric oxide modulates the activity of the hemoproteins prostaglandin I2 synthase and thromboxane A2 synthase. Arch Biochem Biophys. 1997; 347: 174–180.[CrossRef][Medline] [Order article via Infotrieve]
15. Smith WL, Dewitt DL, Allen ML. Bimodal distribution of the prostaglandin I2 synthase antigen in smooth muscle cells. J Biol Chem. 1983; 258: 5922–5926.
16. Wade ML, Voelkel NF, Fitzpatrick FA. "Suicide" inactivation of prostaglandin I2 synthase: characterization of mechanism-based inactivation with isolated enzyme and endothelial cells. Arch Biochem Biophys. 1995; 321: 453–458.[CrossRef][Medline] [Order article via Infotrieve]
17. Numaguchi Y, Naruse K, Harada M, et al. Prostacyclin synthase gene transfer accelerates reendothelialization and inhibits neointimal formation in rat carotid arteries after balloon injury. Arterioscler Thromb Vasc Biol. 1999; 19: 727–733.
18. Craven PA, Studer RK, DeRubertis FR. Thromboxane/prostaglandin endoperoxide–induced hypertrophy of rat vascular smooth muscle cells is signaled by protein kinase C–dependent increases in transforming growth factor-beta. Hypertension. 1996; 28: 169–176.
19. Zucker TP, Bonisch D, Muck S, et al. Thrombin-induced mitogenesis in coronary artery smooth muscle cells is potentiated by thromboxane A2 and involves upregulation of thromboxane receptor mRNA. Circulation. 1998; 97: 589–595.
20. Connolly E, Bouchier-Hayes DJ, Kaye E, et al. Cyclooxygenase isozyme expression and intimal hyperplasia in a rat model of balloon angioplasty. J Pharmacol Exp Ther. 2002; 300: 393–398.
21. Iwashina M, Shichiri M, Marumo F, et al. Transfection of inducible nitric oxide synthase gene causes apoptosis in vascular smooth muscle cells. Circulation. 1998; 98: 1212–1218.
22. Wang H, Keiser JA. Molecular characterization of rabbit CPP32 and its function in vascular smooth muscle cell apoptosis. Am J Physiol. 1998; 274 (pt 2): H1132–H1140.[Medline] [Order article via Infotrieve]
23. Desmouliere A, Badid C, Bochaton-Piallat ML, et al. Apoptosis during wound healing, fibrocontractive diseases and vascular wall injury. Int J Biochem Cell Biol. 1997; 29: 19–30.[CrossRef][Medline] [Order article via Infotrieve]
24. Cornwell TL, Arnold E, Boerth NJ, et al. Inhibition of smooth muscle cell growth by nitric oxide and activation of cAMP-dependent protein kinase by cGMP. Am J Physiol. 1994; 267 (pt 1): C1405–C1413.[Medline] [Order article via Infotrieve]
25. Beasley D, McGuiggin ME. Interleukin 1 induces prostacyclin-dependent increases in cyclic AMP production and does not affect cyclic GMP production in human vascular smooth muscle cells. Cytokine. 1995; 7: 417–426.[CrossRef][Medline] [Order article via Infotrieve]
26. Sachinidis A, Flesch M, Ko Y, et al. Thromboxane A2 and vascular smooth muscle cell proliferation. Hypertension. 1995; 26: 771–780.
27. Catella-Lawson F, McAdam B, Morrison BW, et al. Effects of specific inhibition of cyclooxygenase-2 on sodium balance, hemodynamics, and vasoactive eicosanoids. J Pharmacol Exp Ther. 1999; 289: 735–741.
28. Yan Z, Hansson GK. Overexpression of inducible nitric oxide synthase by neointimal smooth muscle cells. Circ Res. 1998; 82: 21–29.
29. Forfia PR, Zhang X, Ochoa F, et al. Relationship between plasma NOx and cardiac and vascular dysfunction after LPS injection in anesthetized dogs. Am J Physiol. 1998; 274 (pt 2): H193–H201.[Medline] [Order article via Infotrieve]
30. Kutchera W, Jones DA, Matsunami, N et al. Prostaglandin H synthase 2 is expressed abnormally in human colon cancer: evidence for a transcriptional effect. Proc Natl Acad Sci U S A. 1996; 93: 4816–4820.
31. Notoya K, Jovanovic DV, Reboul P, et al. The induction of cell death in human osteoarthritis chondrocytes by nitric oxide is related to the production of prostaglandin E2 via the induction of cyclooxygenase-2. J Immunol. 2000; 165: 3402–3410.
This article has been cited by other articles:
 |
|
 |
|
  J. Kawagoe, M. Ohmichi, S. Tsutsumi, T. Ohta, K. Takahashi, and H. Kurachi Mechanism of the Divergent Effects of Estrogen on the Cell Proliferation of Human Umbilical Endothelial Versus Aortic Smooth Muscle Cells Endocrinology, December 1, 2007; 148(12): 6092 - 6099. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Li, Y.-H. Song, J. Mohler, and P. Delafontaine ANG II induces apoptosis of human vascular smooth muscle via extrinsic pathway involving inhibition of Akt phosphorylation and increased FasL expression Am J Physiol Heart Circ Physiol, May 1, 2006; 290(5): H2116 - H2123. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. M. Antman, D. DeMets, and J. Loscalzo Cyclooxygenase Inhibition and Cardiovascular Risk Circulation, August 2, 2005; 112(5): 759 - 770. [Full Text] [PDF]
|
|
|
|
 |
|
 J.-S. Huang, L.-Y. Chuang, J.-Y. Guh, C.-J. Chen, Y.-L. Yang, T.-A. Chiang, M.-Y. Hung, and T.-N. Liao Effect of Nitric Oxide-cGMP-Dependent Protein Kinase Activation on Advanced Glycation End-Product-Induced Proliferation in Renal Fibroblasts J. Am. Soc. Nephrol., August 1, 2005; 16(8): 2318 - 2329. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||