(Hypertension. 1999;34:132-137.)
© 1999 American Heart Association, Inc.
Scientific Contributions |
Genistein Inhibits Pressure-Induced Expression of c-fos in Isolated Mesenteric Arteries
From the Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Va.
Correspondence to Russell L. Prewitt, PhD, Department of Physiological Sciences, Eastern Virginia Medical School, PO Box 1980, Norfolk, VA 23501. E-mail rlp{at}borg.evms.edu
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Abstract—We have previously demonstrated that elevating intraluminal pressure from 90 to 140 mm Hg in isolated mesenteric arteries increases the expression of proto-oncogenes. These proto-oncogenes encode nuclear transcription factors that regulate the expression of target genes during various stages of the cell cycle. Thus, pressure-induced proto-oncogene expression may represent a mechanism by which pressure can induce growth and/or proliferation of vascular smooth muscle. The purpose of this study was to determine the intracellular signals that contribute to the pressure-induced increase in c-fos expression. Small mesenteric arteries were isolated from male Wistar rats and transferred to a dual-vessel chamber. The arteries were cannulated and slowly equilibrated to initial conditions (90 mm Hg, 37°C) while being continuously superfused with a HEPES-bicarbonate–buffered Krebs' solution. After the equilibration period, the intraluminal pressure in 1 artery was increased to 140 mm Hg for 1 hour. In experiments designed to determine the intracellular signals involved in the pressure-induced increase in c-fos expression, specific inhibitors were introduced to the superfusate reservoir of both arteries before the pressure increase. The arteries were then fixed in phosphate-buffered formalin and embedded in paraffin blocks. Sections of paraffin-embedded arteries were fixed on slides, and the expression of c-fos was determined by in situ hybridization with the use of 35S-labeled riboprobes. The pressure-induced expression of c-fos was not inhibited by nitrendipine (10 µmol/L), a calcium-free Krebs' solution containing EGTA (1 to 2 mmol/L), calphostin C (0.1 µmol/L), or cytochalasin D (0.4 µmol/L) but was inhibited by genistein (30 µmol/L). The results suggest that activation of a tyrosine kinase is required for pressure-induced c-fos expression, but the signaling pathway does not require extracellular calcium entry, intact actin filaments, or protein kinase C. As we have shown previously, the expression of c-fos correlated with wall stress.
Key Words: arteries • proto-oncogene • muscle, smooth, vascular • stress, wall • blood pressure • rats
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A variety of intracellular signal transduction processes in many cell types can be activated by mechanical forces. In the cardiovascular system, mechanical stresses such as pressure and flow contribute to normal and pathological adaptations. Vascular smooth muscle cells (VSMC) are exposed to constant mechanical stimuli in vivo and respond to mechanical forces by contraction, dilation, DNA synthesis, and secretion (for review, see Reference1 ). However, how mechanical forces are sensed by VSMC and the intracellular signal transduction involved in the response are not fully understood.
Human essential hypertension and animal models of hypertension are associated with hypertrophy and hyperplasia of VSMC, as well as eutrophic remodeling of existing components of the arterial wall.2 3 Although numerous factors have been implicated, these structural alterations can be attenuated by protection of the vascular bed from the rise in pressure, suggesting that pressure is a direct stimulus for hypertrophy of VSMC in the arterial wall.4 This hypothesis is supported by experiments in which isolated VSMC grown in culture on flexible plates and exposed to cyclic stretch respond by increased DNA synthesis secondary to the production of autocrine growth factors.5 Cultured VSMC grown on flexible plates have been valuable in studying the role of stretch in growth and gene expression in VSMC, but the response obtained depends on the extracellular matrix proteins on which the cells are cultured. For example, VSMC grown on fibronectin respond by synthesizing DNA, but the same cells cultured on laminin do not. The cells cultured on laminin, however, synthesize smooth muscle–specific myosin, as if changing phenotype from a proliferative to a contractile state. Additionally, the 10% to 30% stretch imposed on the cells5 6 7 8 9 10 11 12 13 is difficult to compare with blood pressure levels seen in vivo. Although this approach is excellent for identification of candidate pathways for signal transduction, their applicability must be tested in an actual artery with normal cell-matrix interactions.
Isolated arteries have been especially useful in studying mechanotransduction in differentiated VSMC while maintaining the integrity of the vascular wall with conditions comparable to those seen in vivo. It has been shown that increases in artery stretch or pressure result in numerous cellular responses, including membrane depolarization,14 calcium entry,15 phospholipase C (PLC) activation,16 17 18 and mitogen-activated protein (MAP) kinase activation.19 20 Previous work from our laboratory has shown that an increase in pressure in isolated mesenteric arteries is sufficient to induce proto-oncogene expression despite an insignificant increase in luminal diameter of only 2.9%.21 A subsequent study showed that proto-oncogene expression correlated with circumferential wall stress rather than stretch of the vascular wall.22 Proto-oncogenes such as c-fos encode nuclear transcription factors that regulate specific genes involved in growth and differentiation of VSMC.23 The purpose of this study was to examine the intracellular signal transduction processes leading to the expression of c-fos in response to increased intraluminal pressure in isolated mesenteric arteries.
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Isolated Artery Experiments
Male Wistar rats (weight, 200 to 400 g) were anesthetized by injection of thiopental (100 mg/kg IM) and killed by cervical dislocation. All experimental procedures were approved by the institutional Animal Care and Use Committee. The intestinal mesentery was exposed by an incision made in the abdominal wall and kept moist with saline solution. The mesenteric arcade was removed and placed in a cooled dissection chamber (4°C) containing dissecting buffer consisting of the following (in mmol/L): 3.0 MOPS, 145 NaCl, 5 KCl, 2.5 CaCl2, 1 MgSO4, 1 KH2PO4, 0.02 EDTA, 2 pyruvate, 5 glucose, and 1% albumin. The arteries (first branch from the superior mesenteric artery) were dissected free of surrounding adipose and connective tissue. Two arterial sections from each animal were dissected and transferred to an isolated dual-vessel chamber (Living Systems), mounted on glass pipettes, and pressurized. The chamber was filled with a HEPES-bicarbonate–buffered Krebs' solution containing the following (in mmol/L): 111 NaCl, 25.7 NaHCO3, 4.9 KCl, 2.5 CaCl2, 1.2 MgSO4, 1.2 KH2PO4, 11.5 glucose, and 10 HEPES. Intraluminal pressure was increased stepwise to 90 mm Hg over a 1-hour period, during which time the artery was slowly warmed to 37°C by controlling the temperature of HEPES-bicarbonate–buffered Krebs' solution (95% air/5% CO2, pH 7.4) continuously superfusing the artery (4 to 5 mL/min). After an additional 1-hour equilibration period, the intraluminal pressure in 1 artery was increased to 140 mm Hg while 1 was maintained at 90 mm Hg for 1 hour.
In experiments designed to elucidate the intracellular signals responsible for the pressure-induced expression of c-fos, arteries were treated as described above, with the exception that pharmacological interventions were introduced to both arteries before the increase in pressure. In experiments designed to elucidate the role of cytoplasmic calcium, a calcium-free Krebs' buffer of similar composition was used with the exception that calcium was replaced by EGTA. All drugs were diluted directly into the superfusate reservoir. The following pharmacological inhibitors were used: calphostin C (protein kinase C [PKC]), nitrendipine (voltage-gated calcium channels), cytochalasin D (actin filament formation), and genistein (tyrosine kinases). For calphostin C and cytochalasin D experiments, the arteries were pretreated for 1 hour before the elevation in pressure. For the other experiments, the arteries were pretreated for 25 minutes before the increase in pressure. Nitrendipine experiments were performed in the dark because this drug is light sensitive. In some arteries, the inhibitory effects of the drugs were verified by their ability to affect contractile response to receptor agonists or KCl, as described in Results. Arterial diameters were monitored with a video microscopy system previously described.21 Wall tension was calculated from these measurements according to the Laplace relation (transmural pressurexradius), and wall stress was derived by dividing wall tension by wall thickness. After the experimental treatment, the vessels were fixed in 10% buffered formalin, dehydrated, and embedded in paraffin.
In Situ Hybridization
Arteries were probed for c-fos mRNA with the use of
in situ hybridization.21 24 Briefly, 4 to 5
cross-sections (4 µm) of arteries were mounted on slides,
deparaffinized, rehydrated, and permeabilized with
proteinase K (5 µg/mL) at room temperature and fixed in 4%
paraformaldehyde for 15 minutes at 4°C. The slides
were covered with 200 µL of prehybridization solution for 2 hours and
then with hybridization solution (prehybridization solution containing
107 cpm per milliliter of
35S-labeled sense or antisense riboprobe for
c-fos mRNA) and incubated overnight in a humidified
hybridization box. The probes were transcribed from cDNA inserted into
the polycloning site of pBluescriptSK+ and were reduced to an average
length of 150 bases by limited alkaline hydrolysis. The slides were
washed in 2x SSC containing 1 mmol/L EDTA and 10 mmol/L
ß-mercaptoethanol and immersed in RNAse A (40 µg/mL) solution for
30 minutes at room temperature to remove unbound probe. Finally, the
slides were washed again in SSC, dehydrated in graded alcohol, and air
dried.
Sections from 1 control and 1 high pressure–treated artery were mounted on each slide to minimize differences in hybridization conditions. Control arteries (no pharmacological treatment) were run each time the procedure was performed on a group of treated arteries to correct for intrarun variation. Slides were exposed to a phosphorimager screen for 7 days, and the results were quantified by densitometric analysis with the use of a Molecular Dynamics phosphorimager and image analysis system. The mean density of as many as 5 cross sections from each artery was calculated to obtain a single value. Nonspecific binding of probe determined from sense values was subtracted from corresponding antisense values to determine specific binding. Typically, the sense values were low or undetectable.
A small number of slides were further processed through autoradiography to show the location of the c-fos expression. The slides were dipped in Kodak NTB2 emulsion, stored in the dark at 4°C, and developed 14 days later.
Materials
The cDNA for rat c-fos (2.116 kb) was kindly donated
by Tom Curran (Roche Institute of Molecular Biology). All other
chemicals were purchased from Sigma Chemical, Kodak, or GIBCO
BRL.
Statistical Analysis
Data are expressed as mean±SEM. Two-way ANOVA with repeated
measures (90 versus 140 mm Hg) was performed separately on 3 runs
of in situ hybridization comparing the untreated controls versus drug
intervention as well as drug-pressure interaction. Comparisons were
considered significant at P<0.05. The association of
c-fos expression with luminal diameter and wall stress was
performed with Pearson product moment correlation. Correlation
between variables were considered statistically significant at
P<0.05.
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Figure 1A shows the location of silver grains produced by the 35S-labeled riboprobe for c-fos mRNA. Expression can be seen throughout the media, indicating that VSMC are the source of the signals measured by phosphorimage densitometry. Figure 1B shows a representative example of a phosphorimage of the arteries as they appeared for quantitation of c-fos expression by the phosphorimager.
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The requirement for calcium influx in c-fos expression was tested with the voltage-gated calcium channel inhibitor nitrendipine (10 µmol/L) or superfusion with a calcium-free Krebs' buffer containing EGTA (Figure 2). Inhibition of voltage-gated calcium entry was verified by the inhibition of contractions after exposure to 60 mmol/L KCl or 2 µmol/L norepinephrine, both of which produced only transient contractions. Depletion of cellular calcium was accomplished by superfusing with a calcium-free Krebs' solution containing the calcium chelator EGTA at either 1 or 2 mmol/L. There was no difference in the results obtained between the 2 concentrations of EGTA, and therefore these groups were combined for statistical comparison. Increasing pressure from 90 to 140 mm Hg caused a significant increase in c-fos expression in all treatment groups, with no statistical difference between treatment groups or treatment-pressure interactions.
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The involvement of PKC and intact actin filaments was investigated with the use of the specific inhibitor of PKC calphostin C and the actin filament–disrupting agent cytochalasin D, respectively (Figure 3). Pretreatment of arteries with calphostin C (0.1 µmol/L) reduced contractions due to the PKC activator phorbol myristate acetate (1 µmol/L) to 5±2 µm compared with 82±13 to 2 µmol/L norepinephrine. Results obtained with the actin filament–disrupting agent cytochalasin D (0.4 µmol/L) almost completely inhibited contractions to 60 mmol/L KCl and 2 µmol/L norepinephrine. Increasing pressure from 90 to 140 mm Hg caused a significant increase in c-fos expression in all groups, with no significant drug treatment effect or treatment-pressure interactions.
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The tyrosine kinase inhibitor genistein (30 µmol/L) had no effect on c-fos expression at 90 mm Hg but prevented the increase in c-fos expression at 140 mm Hg, resulting in a significant treatment-pressure interaction (Figure 4).
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Figure 5 shows all of the c-fos expression data, with the exception of the data in genestein experiments, plotted as a function of wall stress (A), calculated as (vessel radiusxpressure)/wall thickness and as a function of vessel diameter (B). The correlation was very high between c-fos expression and wall stress (r=0.94) but not with diameter (r=0.33). Data from the genestein experiments were excluded because inhibition by the compound prevents c-fos expression from being a function of wall stress. The data points from the nitrendipine experiments have higher density values than the other group data, as also seen in Figure 2, but they fall directly on the regression line.
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Discussion |
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The c-fos proto-oncogene is representative of a family of immediate-early genes encoding transcription factors.23 The Fos protein forms a heterodimeric complex with Jun, the product of the c-jun proto-oncogene. Binding of this complex to the AP-1 DNA sequence regulates the transcription of cell-specific genes.25 Thus, the increased expression of c-fos in arterial smooth muscle may represent an early response to elevated pressure, leading to the coordinated expression of specific proteins involved in the hypertrophy and/or remodeling associated with hypertension. This study supports previous reports from our laboratory that increased pressure is sufficient to induce increases in proto-oncogene expression in isolated arteries,21 and the stimulus may be mediated by an increase in wall stress.22
A new finding in this study is that pressure-induced c-fos expression does not require extracellular calcium entry. Pressure can stimulate depolarization of the vascular smooth muscle and presumably regulate calcium entry through activation of voltage-gated calcium channels.26 Our data suggest that pressure-induced calcium entry is not a requirement for c-fos expression because the increase in expression of c-fos occurs despite the presence of nitrendipine and in the absence of extracellular calcium (Figure 2). The contribution of sarcoplasmic calcium stores under the calcium-free conditions in our experiments is unlikely because prolonged exposure leads to depletion of the sarcoplasmic stores, as evidenced by a weak, transient constriction after exposure to norepinephrine.
Stretch and increased intraluminal pressure can activate PLC in VSMC, which in turn produces the second messengers diacylglycerol and inositol triphosphate.9 16 17 18 Diacylglycerol activates PKC, which has been shown to be involved in numerous cellular functions in vascular smooth muscle, including contraction and proliferation.27 The activation of PKC by phorbol esters or receptor agonists has been shown to increase the expression of c-fos.13 Downregulation of PKC in cultured VSMC by prolonged exposure to phorbol esters inhibited expression of c-fos in phorbol ester and platelet-derived growth factor–stimulated cells, but it only partly inhibited c-fos expression in cyclically stretched cells.13 In cultured smooth muscle cells, pressure-induced increases in DNA synthesis were prevented by inhibitors of PLC or PKC.28 These studies suggest multiple signaling pathways, such as growth factor stimulation and PKC activation in the expression of c-fos. In our study, PKC activation is not required for the pressure-induced increase in c-fos expression (Figure 3). The use of the PKC inhibitor calphostin C offers greater selectivity by competitively binding to the diacylglycerol binding site compared with less selective inhibitors such as staurosporine and H-7, which compete with the ATP binding site of the enzyme.29 Direct measurement of PKC activity is not practical in such small amounts of tissue used in our experiments, but we took advantage of the fact that PKC activation by phorbol esters is able to elicit contractions in vascular smooth muscle to assess the level of inhibition by calphostin C. As mentioned in Results, pretreatment of the arteries for 1 hour with calphostin C (0.1 µmol/L) almost completely inhibited PKC-mediated contractions by 1 µmol/L of the phorbol ester phorbol myristate acetate. It is important to note that PKC exists as multiple isotypes, with varying requirements for activation by calcium and lipids. It is possible that these isotypes also vary in the level of inhibition by calphostin C. Alternatively, pressure-induced PLC activity activates PKC-independent pathways or does not occur in this artery and is not involved in the increase in c-fos expression. The involvement of membrane-derived phospholipid hydrolysis and the activation of PKC-independent pathways in the pressure-induced expression of proto-oncogenes deserve more investigation.
Tyrosine kinase activation has been implicated in the shear stress–induced production of nitric oxide in cultured endothelial cells,30 flow-mediated dilation of isolated arteries,31 deformation-stimulated growth in vascular smooth muscle,32 and hypotonic swelling–induced expression of c-fos in cardiac myocytes.33 These studies implicate tyrosine kinase–dependent signaling in a variety of responses to mechanical stimulation in cardiovascular tissues, including smooth muscle. Our results suggest that the signal transduction pathway involved in the pressure-induced increase in c-fos expression is dependent on tyrosine kinase–mediated pathways. Although our study does not address the tyrosine kinases involved or the potential targets for tyrosine phosphorylation in this response, transcription of c-fos is regulated in part by phosphorylation of p62TCF by MAP kinase.34 MAP kinases, also known as extracellular receptor kinases, are serine-threonine kinases activated by phosphorylation on threonine and tyrosine residues.35 They have been shown to be activated by acute hypertension in vivo, as well as increased mechanical load19 and contractile stimulation in isolated arterial ring preparations.20 Tyrosine kinase activation together with subsequent MAP kinase activation was found to be an immediate and essential step in the hypotonic swelling–induced expression of c-fos in cardiac myocytes. Similar to our results, osmotic stretch-induced c-fos expression in cardiac myocytes was not prevented by inhibitors of other signaling pathways, including PKC, calcium entry, or actin filaments.33 Genistein is a highly specific and rapid inhibitor of tyrosine kinases when used at concentrations <300 µmol/L.36 It is therefore reasonable to assume that this agent acted specifically on tyrosine kinases under our experimental conditions at a concentration of 30 µmol/L. In a similar arterial preparation, genistein has been shown to inhibit receptor-mediated and depolarization-induced contractions at this concentration.37 Additionally, genistein inhibited calcium channel currents in isolated VSMC with an apparent IC50 of 36 µmol/L.38 Thus, activation of tyrosine kinases may result in numerous cellular responses in VSMC. Our results suggest that the effect of genistein on c-fos expression was not related to its potential role in regulating calcium entry because c-fos expression increased despite the presence of nitrendipine and in the absence of extracellular calcium.
The exact nature of the mechanosensitive elements involved in proto-oncogene expression is unknown. The correlation between c-fos expression and wall stress in this study (Figure 5) is in agreement with our previous report that c-myc and 18s rRNA expression is highly correlated with wall stress in isolated arteries22 ; thus, a mechanism by which arterial wall stress is sensed may regulate pressure-mediated tyrosine kinase signaling. The correlation with wall stress explains why the nitrendipine data points appeared to be higher at both 90 and 140 mm Hg in Figure 2. The arteries in these experiments had slightly large diameters.
Mechanotransduction of wall stress into an intracellular signaling pathway is the major unanswered question. Wang et al39 suggested a model in which physical forces exerted on a cell can activate intracellular signals by transmission through actin filaments of the cytoskeleton. Support for the "tensegrity" model comes mainly from the fact that agents that disrupt the integrity of the cytoskeleton can inhibit a variety of signals due to mechanical stimuli. The inhibitor of actin filament formation, cytochalasin D, was unable to inhibit pressure-induced c-fos expression (Figure 3), suggesting that intact actin filaments are not necessary.
Much research has recently focused on the role of the extracellular matrix and integrin adhesion receptors in the response to mechanical stimuli. Integrins are a class of membrane receptors that interact with the extracellular matrix and cytoskeletal proteins and may be involved in the activation of intracellular signals, including tyrosine kinases and MAP kinases (for review, see Rosales et al40 ). Inhibition of integrin receptors with peptides containing the Arg-Gly-Asp binding sequence inhibits both VSMC-mediated contraction41 and endothelium-dependent dilation in isolated arteries.42 Inhibition of integrins in cultured smooth muscle inhibited the stretch-induced expression of platelet-derived growth factor.10 The expression of c-fos in cardiac myocytes exposed to hypotonic solutions was attenuated when cells were stimulated in suspension in the absence of extracellular matrix components.33 Mechanical strain and collagen increased the mitogenic effects of angiotensin II on cultured VSMC.12 These studies demonstrate the importance of the extracellular matrix and integrins in the cellular response to mechanical and receptor-mediated stimulation. It is possible that wall stress is sensed by VSMC contact with the extracellular matrix in our preparation. Although integrins may be capable of transducing certain mechanical stimuli, it remains to be seen if these receptors are involved in the pressure-induced increase in proto-oncogene expression.
In summary, increases in intraluminal pressure in isolated arteries from 90 to 140 mm Hg induced the expression of the proto-oncogene c-fos. The expression of c-fos was correlated with wall stress and not with luminal diameter. The data are consistent with the activation of tyrosine kinases in the pressure-induced increase in c-fos and do not support a requirement for PKC activation, intact actin filaments, or calcium influx.
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Acknowledgments |
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This study was supported by National Institutes of Health grants HL-54810 and HL-36551. Dr Allen was supported by a Fellowship from the American Heart Association, Virginia Affiliate. We would like to thank Dr Paul Kolm for his help in the statistical analysis.
Received December 28, 1998; first decision January 27, 1999; accepted March 5, 1999.
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References |
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|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Osol G. Mechanotransduction by vascular smooth muscle. J Vasc Res. 1995;32:275–292.[Medline] [Order article via Infotrieve]
2.
Hashimoto H, Prewitt RL, Efaw CW. Alterations in the
microvasculature of one-kidney, one-clip hypertensive rats.
Am J Physiol. 1987;253:H933–H940.
3.
Heagerty AM, Aalkjaer C, Bund SJ, Korsgaard N, Mulvany
MJ. Small artery structure in hypertension: dual processes of
remodeling and growth. Hypertension. 1993;21:391–397.
4.
Bund SJ, West KP, Heagerty AM. Effects of protection
from pressure on resistance artery morphology and reactivity in
spontaneously hypertensive and Wistar-Kyoto rats. Circ Res. 1991;68:1230–1240.
5.
Wilson E, Mai Q, Sudhir K, Weiss RH, Ives HE.
Mechanical strain induces growth of vascular smooth muscle cells via
autocrine action of PDGF. J Cell Biol. 1993;123:741–747.
6. Birukov KG, Shirinsky VP, Stepanova OV, Tkachuk VA, Hahn AW, Resink TJ, Smirnov VN. Stretch affects phenotype and proliferation of vascular smooth muscle cells. Mol Cell Biochem. 1995;144:131–139.[Medline] [Order article via Infotrieve]
7.
Akai Y, Homma T, Burns KD, Yasuda T, Badr KF, Harris
RC. Mechanical stretch/relaxation of cultured rat mesangial
cells induces protooncogenes and cyclooxygenase.
Am J Physiol. 1994;267:C482–C490.
8.
Cheng GC, Briggs WH, Gerson DS, Libby P, Grodzinsky
AJ, Gray ML, Lee RT. Mechanical strain tightly controls fibroblast
growth factor-2 release from cultured human vascular smooth muscle
cells. Circ Res. 1997;80:28–36.
9. Lyall F, Deehan MR, Greer IA, Boswell F, Brown WC, McInnes GT. Mechanical stretch increases proto-oncogene expression and phosphoinositide turnover in vascular smooth muscle cells. J Hypertens. 1994;12:1139–1145.[Medline] [Order article via Infotrieve]
10. Wilson E, Sudhir K, Ives HE. Mechanical strain of rat vascular smooth muscle cells is sensed by specific extracellular matrix/integrin interactions. J Clin Invest. 1995;96:2364–2372.
11.
Reusch P, Wagdy H, Reusch R, Wilson E, Ives HE.
Mechanical strain increases smooth muscle and decreases nonmuscle
myosin expression in rat vascular smooth muscle cells. Circ
Res. 1996;79:1046–1053.
12. Sudhir K, Wilson E, Chatterjee K, Ives HE. Mechanical strain and collagen potentiate mitogenic activity of angiotensin II in rat vascular smooth muscle cells. J Clin Invest. 1993;92:3003–3007.
13. Bhalla RC, Sharma RV. Induction of c-fos and elastin gene in response to mechanical stretch of vascular smooth muscle cells. J Vasc Med Biol. 1993;4:135–142.
14.
Harder DR. Pressure-dependent membrane depolarization
in cat middle cerebral artery. Circ Res. 1984;55:197–202.
15.
Zou H, Ratz PH, Hill MA. Role of myosin
phosphorylation and
[Ca2+]i in myogenic
reactivity and arteriolar tone. Am J Physiol. 1995;269:H1590–H1596.
16.
Matsumoto H, Baron CB, Coburn RF. Smooth muscle
stretch-activated phospholipase C activity. Am J
Physiol. 1995;268:C458–C465.
17.
Narayanan J, Imig M, Roman RJ, Harder DR.
Pressurization of isolated renal arteries increases inositol
trisphosphate and diacylglycerol. Am J Physiol. 1994;266:H1840–H1845.
18.
Osol G, Laher I, Kelley M. Myogenic tone is coupled to
phospholipase C and G protein activation in small cerebral arteries.
Am J Physiol. 1993;265:H415–H420.
19.
Adam LP, Franklin MT, Raff GJ, Hathaway DR. Activation
of mitogen-activated protein kinase in porcine carotid
arteries. Circ Res. 1995;76:183–190.
20.
Katoch SS, Moreland RS. Agonist and membrane
depolarization induced activation of MAP kinase in the swine carotid
artery. Am J Physiol. 1995;269:H222–H229.
21.
Allen SP, Liang HM, Hill MA, Prewitt RL. Elevated
pressure stimulates protooncogene expression in isolated mesenteric
arteries. Am J Physiol. 1996;271:H1517–H1523.
22.
Allen SP, Wade SS, Prewitt RL. Myogenic tone attenuates
pressure-induced gene expression in isolated small arteries.
Hypertension. 1997;30:203–208.
23. Gorski DH, Walsh K. Mitogen-responsive nuclear factors that mediate growth control signals in vascular myocytes. Cardiovasc Res. 1995;30:585–592.[Medline] [Order article via Infotrieve]
24. Wilcox JN. Fundamental principles of in situ hybridization. J Histochem Cytochem. 1993;41:1725–1733.[Abstract]
25. Curran T, Franza BR Jr. Fos and Jun: the AP-1 connection. Cell. 1988;55:395–397.[Medline] [Order article via Infotrieve]
26. Wesselman JP, VanBavel E, Pfaffendorf M, Spaan JA. Voltage-operated calcium channels are essential for the myogenic responsiveness of cannulated rat mesenteric small arteries. J Vasc Res. 1996;33:32–41.[Medline] [Order article via Infotrieve]
27.
Lee MW, Severson DL. Signal transduction in vascular
smooth muscle: diacylglycerol second messengers and PKC action.
Am J Physiol. 1994;267:C659–C678.
28. Hishikawa K, Nakaki T, Marumo T, Hayashi M, Suzuki H, Kato R, Saruta T. Pressure promotes DNA synthesis in rat cultured vascular smooth muscle cells. J Clin Invest. 1994;93:1975–1980.
29.
Shimamoto Y, Shimamoto H, Kwan CY, Daniel EE.
Differential effects of putative protein kinase C
inhibitors on contraction of rat aortic smooth muscle.
Am J Physiol. 1993;264:H1300–H1306.
30.
Corson MA, James NL, Latta SE, Nerem RM, Berk BC,
Harrison DG. Phosphorylation of
endothelial nitric oxide synthase in response to fluid
shear stress. Circ Res. 1996;79:984–991.
31.
Muller JM, Davis MJ, Chilian WM. Coronary
arteriolar flow-induced vasodilation signals through tyrosine kinase.
Am J Physiol. 1996;270:H1878–H1884.
32.
Davis MG, Ali S, Leikauf GD, Dorn GW II. Tyrosine
kinase inhibition prevents deformation-stimulated vascular smooth
muscle growth. Hypertension. 1994;24:706–713.
33. Sadoshima J, Qiu Z, Morgan JP, Izumo S. Tyrosine kinase activation is an immediate and essential step in hypotonic cell swelling-induced ERK activation and c-fos gene expression in cardiac myocytes. EMBO J. 1996;15:5535–5546.[Medline] [Order article via Infotrieve]
34. Gille H, Sharrocks AD, Shaw PE. Phosphorylation of transcription factor p62TCF by MAP kinase stimulates ternary complex formation at c-fos promoter. Nature. 1992;358:414–417.[Medline] [Order article via Infotrieve]
35. Ahn NG. The MAP kinase cascade. Discovery of a new signal transduction pathway. Mol Cell Biochem. 1993;127–128:201–209.
36.
Akiyama T, Ishida J, Nakagawa S, Ogawara H, Watanabe S,
Itoh N, Shibuya M, Fukami Y. Genistein, a specific
inhibitor of tyrosine-specific protein kinases.
J Biol Chem. 1987;262:5592–5595.
37. Toma C, Jensen PE, Prieto D, Hughes A, Mulvany MJ, Aalkjaer C. Effects of tyrosine kinase inhibitors on the contractility of rat mesenteric resistance arteries. Br J Pharmacol. 1995;114:1266–1272.[Medline] [Order article via Infotrieve]
38. Wijetunge S, Aalkjaer C, Schachter M, Hughes AD. Tyrosine kinase inhibitors block calcium channel currents in vascular smooth muscle cells. Biochem Biophys Res Commun. 1992;189:1620–1623.[Medline] [Order article via Infotrieve]
39.
Wang N, Butler JP, Ingber DE. Mechanotransduction
across the cell surface and through the cytoskeleton.
Science. 1993;260:1124–1127.
40. Rosales C, O'Brien V, Kornberg L, Juliano R. Signal transduction by cell adhesion receptors. Biochim Biophys Acta. 1995;1242:77–98.[Medline] [Order article via Infotrieve]
41.
Mogford JE, Davis GE, Platts SH, Meininger GA. Vascular
smooth muscle 
vß3
integrin mediates arteriolar vasodilation in response to RGD peptides.
Circ Res. 1996;79:821–826.
42.
Muller JM, Chilian WM, Davis MJ. Integrin
signaling transduces shear stress–dependent vasodilation of
coronary arterioles. Circ Res. 1997;80:320–326.
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C. M. Spofford and W. M. Chilian The elastin-laminin receptor functions as a mechanotransducer in vascular smooth muscle Am J Physiol Heart Circ Physiol, March 1, 2001; 280(3): H1354 - H1360. [Abstract] [Full Text] [PDF]
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J. P. M. Wesselman, A. D. Dobrian, S. D. Schriver, and R. L. Prewitt Src Tyrosine Kinases and Extracellular Signal-Regulated Kinase 1/2 Mitogen-Activated Protein Kinases Mediate Pressure-Induced C-Fos Expression in Cannulated Rat Mesenteric Small Arteries Hypertension, March 1, 2001; 37(3): 955 - 960. [Abstract] [Full Text] [PDF]
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