doi: 10.1161/hy02t2.102808
(Hypertension. 2002;39:382.)
© 2002 American Heart Association, Inc.
Scientific Contributions |
Trophic Effects of the Cyclooxygenase-2 Product Prostaglandin E2 in Cardiac Myocytes
From the Hypertension and Vascular Research Division, Henry Ford Hospital, Detroit, Mich.
Correspondence to Margot C. LaPointe, PhD, Hypertension and Vascular Research Division, Henry Ford Hospital, 2799 West Grand Blvd, Detroit, MI 48202-2689. E-mail mclapointe{at}aol.com
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Interleukin-1ß (IL-1ß), a proinflammatory cytokine, induces cyclooxygenase-2 (COX-2) in cultured neonatal ventricular myocytes (NVMs), resulting in the preferential production of prostaglandin E2 (PGE2). To explain the preferential PGE2 release by myocytes, we studied whether its specific synthase, PGE2 synthase (PGES), is also induced by IL-1ß. Because COX-2 has been extensively associated with cell growth, we questioned whether PGE2 plays a role in cardiac cell growth. IL-1ß–treated myocytes showed induction of PGES protein and mRNA by Western blot and reverse transcription–polymerase chain reaction, respectively. Immunofluorescence studies revealed perinuclear localization of COX-2 and PGES in IL-1ß–treated myocytes. Exogenous PGE2 increased protein synthesis in NVMs, as indicated by a 1.6-fold increase in [3H]leucine incorporation, comparable to the known hypertrophic factor phenylephrine (1.6-fold). Because PGE2 exerts different effects through 4 receptor subtypes (EP1, EP2, EP3, and EP4), we investigated whether these receptors are functional in myocytes. Treatment of NVMs with the selective EP1/EP3 agonist sulprostone significantly increased protein synthesis (1.7-fold), whereas the EP1/EP2 antagonist AH6809 blocked this effect by 43%. In contrast, AH6809 had no effect on PGE2-induced protein synthesis. Regarding second messengers, sulprostone had no effect on cAMP, whereas PGE2 increased it. We concluded that (1) PGE2 production requires the induction of its specific synthase; (2) in myocytes, the inducible enzymes COX-2 and PGES are perinuclear; and (3) PGE2 and sulprostone induce cardiac myocyte growth but seem to activate a different subset of EP receptors.
Key Words: prostaglandins • hypertrophy, cardiac • receptors • myocytes
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Cyclooxygenase (COX) catalyzes the oxygenation and reduction of arachidonic acid, leading to the formation of hydroxy endoperoxide (prostaglandin H2 [PGH2]). PGH2 serves as a substrate for discrete prostaglandin (PG) synthases, which give rise to PGs such as PGE2, PGF2
, PGD2, PGI2, and thromboxane A2. There are 2 COX isoforms, COX-1 and COX-2. COX-1 is constitutively expressed in almost all cell types and plays a role in physiological homeostasis. In contrast, COX-2 is normally absent but can be induced by different stimuli, such as inflammatory cytokines, in many cells.1,2 We have previously shown that in neonatal ventricular myocytes (NVMs), the induction of COX-2 by interleukin-1ß (IL-1ß) results in the preferential production of PGE2.3 Recent reports have shown that the capacity of various cell types to produce PGE2 over other PGs depends not only on the induction of COX-2 but also on PGE2 synthase (PGES). In some cell types, COX-2 and PGES are colocalized in a perinuclear distribution.4–6
The biological actions of PGE2 are mediated through 4 specific G-coupled receptors, EP1, EP2, EP3, and EP4, which differ in structure, ligand-binding properties, activation of signal transduction pathways, and tissue distribution.7 Although activation of EP2 and EP4 (coupled to Gs) increases cAMP, EP1 receptors mediate Ca2+ mobilization.7,8 Studies in vivo and in vitro suggest that under normal conditions, the EP3 receptor couples to either Gi or Gq, decreasing cAMP.7,9 Previous reports have shown acute upregulation of EP3 receptors in the pig heart after myocardial infarction.10,11 Nevertheless, the role of EP receptors and their distribution in cardiac cells remains uncertain.
It has been suggested that prostanoids work at or near their site of production as autocrine and paracrine factors.7 PGE2 induces mitogenesis and tumor growth.12–15 Other studies have suggested that proinflammatory cytokines can induce hypertrophy in vitro and in vivo.16–20 IL-1ß is induced in the heart in response to chronic pressure overload, ß-adrenergic stimulation, and infarction.21–23 Thus, in the present study, we examined the mechanisms by which myocytes produce high levels of PGE2, concentrating on IL-1ß induction of PGES and localization of COX-2 and PGES within the cell. We also studied whether PGE2 increases myocyte growth and the receptors that mediate its response.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Cell Culture
Primary cultures of NVMs were derived from the digestion of 1- to 2-day-old neonatal Sprague-Dawley rat hearts (Charles River, Kalamazoo, Mich), as described previously.24 After 40 hours in culture with DMEM plus 10% FBS (Gibco), serum-free medium supplemented with glutamine, insulin, selenium, and transferrin (SF-DMEM) was then added for 24 hours. Neonatal cardiac fibroblasts were generated at the preplate stage of the myocyte preparation and passaged twice before use. This protocol was approved by the Henry Ford Hospital Institutional Animal Care and Use Committee.
EIA for PGE2, PGF2, and the Stable PGI2 Metabolite 6-Keto-PGF1
Cells (1x106 cells per well of a 6-well plate) were treated with or without 5 ng/mL (0.3 nmol/L) IL-1ß in 1 mL SF-DMEM for 24 hours. Aliquots of medium were diluted if necessary and assayed for specific PGs by use of enzyme immunoassay (EIA) kits from Cayman. Values from triplicate wells were averaged and normalized to protein (nanograms per milligram protein). Data from multiple experiments were expressed as mean±SE.
Isolation of Protein and Western Blot
After medium was removed for the assay of prostanoids (see above), protein was isolated from cardiac myocytes by using lysis buffer and protease inhibitors and subjected to Western blot as described previously.25 The 72-kDa COX-2 protein was detected as described previously,26 whereas the 17-kDa PGES protein was detected in membrane-enriched preparations generated by ultracentrifugation of the cell lysate through a 7-mL cushion of 6% sucrose at 230 000g for 40 minutes. The pellet was resuspended in lysis buffer containing protease inhibitors. The 17-kDa PGES was detected with an anti-rabbit polyclonal antibody (Cayman) diluted 1:500. The appropriate secondary antibody linked to horseradish peroxidase (1:2000) was used for chemiluminescent detection with ECL Western blot reagents (Amersham Pharmacia Biotech). The signal was detected by exposure to Fuji RX film and quantified by laser densitometry.
EIA for cAMP
cAMP in NVM cell lysates was determined by EIA with the use of the low pH kit from R & D Systems, according to their instructions. NVMs (0.5x106) were stimulated with vehicle, isoproterenol (ISO), sulprostone, or PGE2 for 30 minutes in the presence of 1 mmol/L 3-isobutyl-l-methylxanthine to inhibit phosphodiesterase activity. Results were expressed as picomoles cAMP per 0.5x106 cells. Triplicate values from 3 wells were averaged for each treatment in each separate experiment.
Isolation of RNA and RT-PCR
Total RNA was isolated from control and IL-1ß–treated NVMs with the use of Tri Reagent (MRC Inc) according to the manufacturer’s instructions. Reverse transcription (RT) of total RNA (2 µg) was performed in a total volume of 25 µL by using 1 µg random primer (Gibco-BRL) and 200 U MMLV reverse transcriptase (Promega). Aliquots (5 µL) of the resulting cDNA were subjected to polymerase chain reaction (PCR) for amplification of COX-2 (462 bp), PGES (473 bp), and GAPDH (554 bp). Oligonucleotide primers (5' to 3') for rat COX-2 were AGT ACG AAG ACC CTG CCT ACG (sense) and TAA GTT GGT GGG CTG TCA AT (antisense). Primers for the complete PGES cDNA were ATG ACT TCC CTG GGT TTG GTG (sense) and TCA GCT GCT GGT CAC AGA TGG (antisense). Primers for rat GAPDH were AAT GCA TCC TGC ACC ACC TGC (sense) and GGA GGC CAT GTA GGC CAT GAG GTC (antisense). A PTC-100 thermal controller (MJ Research, Inc) was used for amplification, and the program settings were denaturation for 30 seconds at 95°C, annealing for 60 seconds at 58°C, and extension for 90 seconds at 72°C for 40 cycles. PCR products were separated out on a 1.0% agarose gel, stained with ethidium bromide, and photographed.
Confocal Microscopy
Fifty thousand myocytes were plated on coverslips coated with fibronectin (10 µg/mL) and grown in 10% serum. After substitution with SF-DMEM for 24 hours and treatment of the cells with 5 ng/mL IL-1ß or vehicle for another 24 hours, they were washed twice with PBS and fixed in 4% paraformaldehyde in PBS for 15 minutes. Cells were then permeabilized in 0.1% Triton X-100 in PBS for 10 minutes and blocked for 1 hour in 1% BSA/Tris-buffered saline with 0.1% Tween (TBS-T). Cells were incubated with the primary antibody (diluted 1:100 in 1% BSA/TBS-T) for 60 minutes and then washed with TBS-T. The secondary antibody (donkey anti-goat and goat anti-rabbit Alexa fluor 488 for COX-2 and PGES, respectively) was diluted 1:2000 in 1% BSA/TBS-T and added to the cells for 45 minutes in the dark. After consecutive washes for 1 hour with TBS-T, samples were mounted in Fluoromount-G (Southern Biotechnology Associates). Coverslips were examined under oil immersion at x63 magnification. Immunofluorescence was detected after excitation at 488 nm with use of a Bio-Rad MRC 1024 confocal laser scanning microscope.
Measurement of Protein Synthesis
Protein synthesis was determined by the incorporation of [3H]leucine into trichloroacetic acid–insoluble material after 48 hours, as described previously.27 NVMs were treated with phenylephrine (Phe), PGF2, PGE2, or beraprost for the experiments in Figure 4, with sulprostone and AH6809 for the experiments in Figure 5, and with cAMP for the experiments in Figure 6B. All treatments lasted 48 hours. For each treatment in each experiment, counts per minute from triplicate filters were averaged.
|
|
|
Statistical Analysis
Values are represented as mean±SE. Differences in mean values were analyzed by 1-way ANOVA, with pairwise multiple comparisons made by the Student-Newman-Keuls method. A value of P<0.05 was considered significant.
Chemicals
PGE2, PGF2, beraprost, PGES antibody, AH6809, and sulprostone were obtained from Cayman. COX-2 antibody was obtained from Santa Cruz. L-[3,4,4-3H(N)]leucine was purchased from NEN/Dupont, and IL-1ß was purchased from Collaborative Biomedical Products. Dibutyryl cAMP was purchased from Sigma Chemical Co. For confocal microscopy, secondary antibodies were obtained from Molecular Probes. All other laboratory supplies and chemicals were obtained from Sigma, Fisher, and VWR Scientific.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Effect of IL-1ß on Myocyte and Fibroblast PG Production
Experiments were conducted to characterize the profile of PGs released by myocytes and fibroblasts in the presence and absence of 5 ng/mL IL-1ß for 24 hours. Basal production of each PG in untreated myocytes was in the range of 0.1 to 2 ng/mg protein, whereas in fibroblasts it was 1 to 5 ng/mg protein. In IL-1ß–stimulated NVMs, PGE2 production was much higher than PGI2 and PGF2
production and exceeded the total PG production by fibroblasts (Figures 1A and 1B). In confluent cultures of neonatal cardiac fibroblasts (passage 3), the pattern of PG production was different from that in myocytes, with PGI2 being the major product (Figure 1B). The robust production of PGs by myocytes and fibroblasts was accompanied by the induction of COX-2.
|
Effect of IL-1ß on PGES Expression
Because of the high level of PGE2 produced by NVMs and recent reports of PGES upregulation in response to inflammatory stimuli,5,6,28 we questioned whether IL-1ß also regulates PGES expression in cardiac myocytes. RT-PCR studies (Figure 2A) indicate that IL-1ß treatment of NVMs induced PGES mRNA (lane 6), in addition to COX-2 mRNA (lane 2), whereas untreated control NVMs did not express either gene product (lanes 1 and 5). We also amplified a signal for GAPDH mRNA from IL-1ß–treated and control NVMs (lanes 3 and 4) as a control for RNA integrity in our samples. PGES protein was detected by Western blot of a membrane-enriched fraction of IL-1ß–treated NVMs, confirming the RT-PCR results (Figure 2B). Thus, PGE2 production in NVMs requires coordinated regulation of both PGES and COX-2.
|
Subcellular Localization of COX-2 and PGES in Myocytes
Confocal microscopy was performed to determine the subcellular localization of COX-2 and PGES in NVMs. Separate coverslips were analyzed by confocal microscopy for immunofluorescence with the use of specific polyclonal antibodies for each inducible enzyme. In Figure 3, immunofluorescence micrographs (panels D and H) and their corresponding transmittance views (panels C and G) are shown. Results from the examination of multiple coverslips indicate that both COX-2 and PGES were localized in a perinuclear distribution. Untreated cells incubated with both the primary and secondary antibodies were used as controls. When controls were examined under the same conditions that produced immunofluorescence for COX-2 and PGES, only background immunofluorescence was observed (panels B and F).
|
Effect of Exogenous PGE2 on Myocyte Growth
COX-2 and/or its products have been associated with cell growth.29–31 In particular, PGE2 has been found to be mitogenic in different cell types,12–15 although its role in the heart remains unclear. Because PGE2 was produced in the greatest amount by myocytes, we questioned whether it plays a role in cell growth. Figure 4A shows that protein synthesis increased 1.6±0.1-fold when NVMs were treated with 1 µmol/L PGE2 for 48 hours. As positive controls, we used the known hypertrophic factors Phe (50 µmol/L) and PGF2 (1 µmol/L), both of which produced a significant increase in protein synthesis comparable to that of PGE2 (Phe 1.6±0.2-fold, PGF2 1.9±0.1-fold). As an additional control for nonspecific effects of PGs on growth, NVMs were treated for 48 hours with the PGI2 analogue beraprost, which had no effect on protein synthesis (Figure 4B).
Involvement of EP Receptors in Protein Synthesis
To determine whether EP1 and EP3 are linked to growth in NVMs, pharmacological approaches were used. We first tested the effect of the EP1/EP3-selective agonist sulprostone on protein synthesis. Cardiac myocytes were treated with 1 µmol/L sulprostone in the presence of [3H]leucine for 48 hours. Sulprostone increased protein synthesis 1.7±0.1-fold, indicating that the activation of EP1 and/or EP3 receptors is hypertrophic (Figure 5A). Sulprostone was also stimulatory at 10-8 mol/L (1.5±0.2-fold increase, n=6). We next tested the effect of the EP1/EP2 antagonist AH6809. Figure 5A shows that treatment with 10 µmol/L AH6809 in combination with sulprostone reduced protein synthesis by 43% (sulprostone 1.7±0.1-fold increase, sulprostone+AH6809 1.4±0.05-fold increase). Because sulprostone is specific for EP1 and EP3 receptors and because AH6809 blocks EP1/EP2,, our data clearly implicate EP1. In addition, because the effect of AH6809+sulprostone was statistically different from that of AH6809 alone, our data suggest that the remaining portion of the effect of sulprostone involves EP3.
Because PGE2 can bind to all 4 EP receptors, we next investigated the effect of AH6809 on PGE2 stimulation of protein synthesis. We reasoned that if PGE2 stimulation of protein synthesis is inhibited by AH6809, similar to the pattern seen in Figure 5A, this would verify the involvement of EP1. On the other hand, if AH6809 has no effect, then this might suggest that PGE2 preferentially acts on EP3 and/or EP4 in NVMs. Results in Figure 5B indicate that AH6809 was unable to inhibit protein synthesis in PGE2-stimulated NVMs, suggesting a role for EP3 and/or EP4.
Because the previous data suggested that sulprostone and PGE2 were acting through different receptor subtypes and, thus, through different signaling mechanisms, we tested the effect of both compounds on cAMP production. NVMs were treated with 1 µmol/L PGE2 sulprostone or with the ß-adrenergic agonist ISO (10 µmol/L) as a positive control and assayed for cAMP production after 30 minutes. Figure 6A shows that PGE2 stimulated cAMP production to the same extent as did the positive control ISO (ISO 14.8±2.2-fold, PGE2 12.3±1.5-fold). As expected, sulprostone had no effect on cAMP levels (control 0.9±0.2-fold, sulprostone 0.8±0.2-fold). Finally, we found that cAMP itself (1 mmol/L dibutyryl cAMP for 48 hours) stimulated protein synthesis in NVMs (Figure 6B). Thus, PGE2 uses a signaling mechanism that is different from that of sulprostone, and this most likely involves EP4 and cAMP production.
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
We have previously shown that the proinflammatory cytokine IL-1ß regulates the synthesis of COX-2 and generates PGE2 in NVMs.32 The present study extends our understanding of PG production and the regulation of COX-2 in the heart to the cardiac fibroblast, where COX-2 is also induced by an inflammatory stimulus, but the pattern of PG synthesis is different from that in myocytes. In fibroblasts, there is preferential release of PGI2. In contrast to fibroblasts, myocytes produce greater amounts of PGs in response to IL-1ß, and PGE2 production vastly exceeds the production of all other PGs. Because of this, we concentrated the present study on PGE2 and its effect on the cardiac myocyte.
In the present study, we demonstrate for the first time that PGES is upregulated by IL-1ß in NVMs and is localized to a membrane-enriched subcellular fraction. In agreement with our data, recent studies have shown that PGES expression is markedly upregulated by proinflammatory stimuli in various cell types.5,6 PGES has been detected in both cytosolic and microsomal fractions within various cells. Cytosolic PGES is a constitutive enzyme capable of converting COX-1–derived PGH2 to PGE2, whereas microsomal PGES is inducible.33,34 Studies have demonstrated that COX-2 and microsomal PGES are colocalized in the perinuclear envelope, suggesting coordinated biosynthetic activity between the enzymes.33 We extended this observation to cardiac myocytes by use of immunofluorescence and confocal microscopy, clearly showing a perinuclear distribution of COX-2 and PGES after IL-1ß treatment. Because COX-2 and PGES mRNA and protein are not present in untreated NVMs, we hypothesize that after IL-1ß stimulation of their expression, they are targeted to microsomes/membranes in and around the nucleus, where they interact to produce high levels of PGE2. Because PGES is critical for the production of high levels of PGE2, this enzyme seems to play a role in the inflammatory response that is as important as COX-2. Thus, molecular mechanisms that result in the induction of PGES need to be elucidated; furthermore, clarification of the protein-protein interactions may explain how these 2 enzymes are effectively regulated.
Although there are not many studies examining the role of COX-2 in cell growth in the heart, there is considerable evidence indicating that COX-2 is involved in tumorigenesis.12,35 Nonsteroidal anti-inflammatory drugs have been shown to control the size of some tumors.12,29,36 In addition, COX-2 has been implicated in the proliferation of smooth muscle cells.31 Interestingly, PGE2 has also been implicated in cell growth, in that HEK293 cells overexpressing COX-2 and PGES were found to grow rapidly.33 The present study indicates that PGE2, but not PGI2, plays an important role in cardiac myocytes by inducing protein synthesis to an extent comparable to that of the known hypertrophic factors Phe and PGF2. Studies have shown that PGF2 is a hypertrophic growth factor in vivo and in vitro, but studies of PGE2 have not yielded clear-cut results.37,38 Some indirect evidence suggests the participation of PGE2 in cardiac fibroblast growth after myocardial infarction,39,40 but these studies used nonselective COX inhibitors, so that the role of COX-2 could not be clearly ascertained. Preliminary studies from our laboratory suggest that PGE2 analogues can stimulate fibroblast proliferation in vitro (authors’ unpublished data, 2001).
Our sulprostone data indicate that EP1 and EP3 are hypertrophic in NVMs, whereas our PGE2 data implicate EP4 and possibly EP3. To definitively determine whether EP4 and EP3 play a role in PGE2-stimulated protein synthesis will require the use of pure EP subtype antagonists or studies in EP3 and EP4 knockout mice. In general, little is known about the type and role of the PG receptors in the individual cell types of the heart. The presence of mRNA for the 4 EP receptors in a variety of adult mouse tissues has been examined, and it was found that in whole heart homogenates, EP3 and EP4 were expressed, although EP4 mRNA was more abundant than EP3 mRNA.41 The fact that EP1 mRNA was not detected in the adult mouse heart may simply reflect the relative insensitivity of the Northern blot for measuring low-abundance mRNAs or differences in the regulation of EP1 in neonatal and adult rodent hearts. In fact, preliminary data from our laboratory indicate that EP1, EP3, and EP4 can be detected by Western blot of membrane-enriched preparations of NVMs (authors’ unpublished data, 2001). Although EP receptors are present in plasma membranes, perinuclear distribution has been found.42,43 Given that PGs are rapidly degraded and that COX-2 and PGES are clearly perinuclear, PGE2 may also act via intracellular EP receptors. At this point, we have not determined whether the EP receptors are localized to specific subcellular compartments.
EP receptors belong to the family of 7–transmembrane-domain receptors, which couple to large heterotrimeric G proteins. EP2 and EP4 are coupled to Gs and result in increases in cAMP, whereas EP3 couples to Gi, and EP1 is linked to increased intracellular calcium. Gi has been shown to couple to pathways involved in growth, including the activation of mitogen-activated protein kinase.44 Activation of both Gs and Gi has been linked to increased protein synthesis in cardiac myocytes in vitro.45,46 It is well known that EP1 increases intracellular calcium, and there is evidence indicating that increases in calcium are coupled to growth-promoting pathways, including activation of protein kinase C, calcium-calmodulin protein kinase, and calcineurin.47,48 Given that we have implicated EP1 and EP3 in myocyte hypertrophy in vitro, it would be interesting to determine whether there is chronic upregulation of these receptors in pathophysiological processes in the heart, such as pressure overload and infarction.
In summary, the present study has characterized molecular events underlying the very large increase in PGE2 in myocytes after IL-1ß treatment and has implicated an inducible PGES localized to a membrane-enriched fraction in this process. Moreover, COX-2 and PGES are localized in a perinuclear distribution in myocytes, which may be critical for the coupling of PGH2 with PGE2 synthesis. The present study also indicates that EP1, EP3, and EP4 are involved in the regulation of protein synthesis. Thus, we believe that in addition to COX-2, PGES and EP receptors could serve as novel therapeutic targets for inflammation, cell growth, and remodeling in the heart.
|
Acknowledgments |
|---|
This work was supported by National Institutes of Health grant P01 HL-28982 (Dr LaPointe) and American Heart Association Postdoctoral Fellowship D11533 (Dr Mendez).
Received September 22, 2001; first decision October 25, 2001; accepted November 7, 2001.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Vane JR, Bakhle YS, Botting RM. Cyclooxygenases 1 and 2. Annu Rev Pharmacol Toxicol. 1998; 38: 97–120.[CrossRef][Medline] [Order article via Infotrieve]
2. Williams CS, DuBois RN. Prostaglandin endoperoxide synthase: why two isoforms? Am J Physiol. 1996; 270: G393–G400.[Medline] [Order article via Infotrieve]
3. LaPointe MC, Isenovic E. Interleukin-1ß regulation of inducible nitric oxide synthase and cyclooxygenase-2 involves the p42/44 and p38 MAPK signaling pathways in cardiac myocytes. Hypertension. 1999; 33: 276–282.
4. Spencer AG, Woods JW, Arakawa T, Singer II, Smith WL. Subcellular localization of prostaglandin endoperoxide H synthases-1 and -2 by immunoelectron microscopy. J Biol Chem. 1998; 273: 9886–9893.
5. Matsumoto H, Naraba H, Murakami M, Kudo I, Yamaki K, Ueno A, Oh-Ishi S. Concordant induction of prostaglandin E2 synthase with cyclooxygenase-2 leads to preferred production of prostaglandin E2 over thromboxane and prostaglandin D2 in lipopolysaccharide-stimulated rat peritoneal macrophages. Biochem Biophys Res Commun. 1997; 230: 110–114.[CrossRef][Medline] [Order article via Infotrieve]
6. Jakobsson PJ, Thoren S, Morgenstern R, Samuelsson B. Identification of human prostaglandin E synthase: a microsomal, glutathione-dependent, inducible enzyme, constituting a potential novel drug target. Proc Natl Acad Sci U S A. 1999; 96: 7220–7225.
7. Narumiya S, Sugimoto Y, Ushikubi F. Prostanoid receptors: structures, properties, and functions. Physiol Rev. 1999; 79: 1193–1226.
8. Watabe A, Sugimoto Y, Honda A, Irie A, Namba T, Negishi M, Ito S, Narumiya S, Ichikawa A. Cloning and expression of cDNA for a mouse EP1 subtype of prostaglandin E receptor. J Biol Chem. 1993; 268: 20175–20178.
9. Namba T, Sugimoto Y, Negishi M, Irie A, Ushikubi F, Kakizuka A, Ito S, Ichikawa A, Narumiya S. Alternative splicing of C-terminal tail of prostaglandin E receptor subtype EP3 determines G-protein specificity. Nature. 1993; 365: 166–170.[CrossRef][Medline] [Order article via Infotrieve]
10. Hohlfeld T, Zucker TP, Meyer J, Schror K. Expression, function, and regulation of E-type prostaglandin receptors (EP3) in the nonischemic and ischemic pig heart. Circ Res. 1997; 81: 765–773.
11. Hohlfeld T. Regulation of prostaglandin receptors in myocardial ischemia. Agents Actions Suppl. 1995; 45: 33–37.[Medline] [Order article via Infotrieve]
12. Marnett LJ. Aspirin and the potential role of prostaglandins in colon cancer. Cancer Res. 1992; 52: 5575–5589.
13. Langenbach R, Loftin C, Lee C, Tiano H. Cyclooxygenase knockout mice: models for elucidating isoform-specific functions. Biochem Pharmacol. 1999; 58: 1237–1246.[CrossRef][Medline] [Order article via Infotrieve]
14. Bamba H, Ota S, Kato A, Matsuzaki F. Nonsteroidal anti-inflammatory drugs may delay the repair of gastric mucosa by suppressing prostaglandin-mediated increase of hepatocyte growth factor production. Biochem Biophys Res Commun. 1998; 245: 567–571.[CrossRef][Medline] [Order article via Infotrieve]
15. Sheng H, Shao J, Washington MK, DuBois RN. Prostaglandin E2 increases growth and motility of colorectal carcinoma cells. J Biol Chem. 2001; 276: 18075–18081.
16. Thaik CM, Calderone A, Takahashi N, Colucci WS. Interleukin-1 beta modulates the growth and phenotype of neonatal rat cardiac myocytes. J Clin Invest. 1995; 96: 1093–1099.[Medline] [Order article via Infotrieve]
17. Palmer JN, Hartogensis WE, Patten M, Fortuin FD, Long CS. Interleukin-1 beta induces cardiac myocyte growth but inhibits cardiac fibroblast proliferation in culture. J Clin Invest. 1995; 95: 2555–2564.[Medline] [Order article via Infotrieve]
18. Ng DC, Long CS, Bogoyevitch MA. A role for the extracellular signal-regulated kinase and p38 mitogen-activated protein kinases in interleukin-1 beta-stimulated delayed signal transducer and activator of transcription 3 activation, atrial natriuretic factor expression, and cardiac myocyte morphology. J Biol Chem. 2001; 276: 29490–29498.
19. Yokoyama T, Nakano M, Bednarczyk JL, McIntyre BW, Entman M, Mann DL. Tumor necrosis factor-alpha provokes a hypertrophic growth response in adult cardiac myocytes. Circulation. 1997; 95: 1247–1252.
20. Kubota T, McTiernan CF, Frye CS, Slawson SE, Lemster BH, Koretsky AP, Demetris AJ, Feldman AM. Dilated cardiomyopathy in transgenic mice with cardiac-specific overexpression of tumor necrosis factor-alpha. Circ Res. 1997; 81: 627–635.
21. Ono K, Matsumori A, Shioi T, Furukawa Y, Sasayama S. Cytokine gene expression after myocardial infarction in rat hearts: possible implication in left ventricular remodeling. Circulation. 1998; 98: 149–156.
22. Shioi T, Matsumori A, Kihara Y, Inoko M, Ono K, Iwanaga Y, Yamada T, Iwasaki A, Matsushima K, Sasayama S. Increased expression of interleukin-1 beta and monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 in the hypertrophied and failing heart with pressure overload. Circ Res. 1997; 81: 664–671.
23. Murray DR, Prabhu SD, Chandrasekar B. Chronic beta-adrenergic stimulation induces myocardial proinflammatory cytokine expression. Circulation. 2000; 101: 2338–2341.
24. LaPointe MC, Sitkins JR. Phorbol ester stimulates the synthesis and secretion of brain natriuretic peptide from neonatal rat ventricular cardiocytes: a comparison with the regulation of atrial natriuretic factor. Mol Endocrinol. 1993; 7: 1284–1296.
25. LaPointe MC, Sitkins JR. Mechanisms of interleukin-1beta regulation of nitric oxide synthase in cardiac myocytes. Hypertension. 1996; 27: 709–714.
26. Schuette R, LaPointe MC. Phorbol ester stimulates cyclooxygenase-2 expression and prostanoid production in cardiac myocytes. Am J Physiol. 2000; 279: H719–H725.
27. Harding P, Carretero OA, LaPointe MC. Effects of interleukin-1 beta and nitric oxide on cardiac myocytes. Hypertension. 1995; 25: 421–430.
28. Watanabe K, Kurihara K, Tokunaga Y, Hayaishi O. Two types of microsomal prostaglandin E synthase: glutathione-dependent and -independent prostaglandin E synthases. Biochem Biophys Res Commun. 1997; 235: 148–152.[CrossRef][Medline] [Order article via Infotrieve]
29. Sheng H, Shao J, Kirkland SC, Isakson P, Coffey RJ, Morrow J, Beauchamp RD, DuBois RN. Inhibition of human colon cancer cell growth by selective inhibition of cyclooxygenase-2. J Clin Invest. 1997; 99: 2254–2259.[Medline] [Order article via Infotrieve]
30. Ohnaka K, Numaguchi K, Yamakawa T, Inagami T. Induction of cyclooxygenase-2 by angiotensin II in cultured rat vascular smooth muscle cells. Hypertension. 2000; 35: 68–75.
31. Young W, Mahboubi K, Haider A, Li I, Ferreri NR. 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.
32. LaPointe MC, Sitkins JR. Phospholipase A2 metabolites regulate inducible nitric oxide synthase in myocytes. Hypertension. 1998; 31: 218–224.
33. Murakami M, Naraba H, Tanioka T, Semmyo N, Nakatani Y, Kojima F, Ikeda T, Fueki M, Ueno A, Oh-Ishi S, et al. Regulation of prostaglandin E2 biosynthesis by inducible membrane-associated prostaglandin E2 synthase that acts in concert with cyclooxygenase-2. J Biol Chem. 2000; 275: 32783–32792.
34. Tanioka T, Nakatani Y, Semmyo N, Murakami M, Kudo I. Molecular identification of cytosolic prostaglandin E2 synthase that is functionally coupled with cyclooxygenase-1 in immediate prostaglandin E2 biosynthesis. J Biol Chem. 2000; 275: 32775–32782.
35. Oshima M, Dinchuk JE, Kargman SL, Oshima H, Hancock B, Kwong E, Trzaskos JM, Evans JF, Taketo MM. Suppression of intestinal polyposis in Apc delta716 knockout mice by inhibition of cyclooxygenase 2 (COX-2). Cell. 1996; 87: 803–809.[CrossRef][Medline] [Order article via Infotrieve]
36. Tsujii M, Kawano S, Tsuji S, Sawaoka H, Hori M, DuBois RN. Cyclooxygenase regulates angiogenesis induced by colon cancer cells. Cell. 1998; 93: 705–716.[CrossRef][Medline] [Order article via Infotrieve]
37. Adams JW, Migita DS, Yu MK, Young R, Hellickson MS, Castro-Vargas FE, Domingo JD, Lee PH, Bui JS, Henderson SA. Prostaglandin F2 alpha stimulates hypertrophic growth of cultured neonatal rat ventricular myocytes. J Biol Chem. 1996; 271: 1179–1186.
38. Lai J, Jin H, Yang R, Winer J, Li W, Yen R, King KL, Zeigler F, Ko A, Cheng J, et al. Prostaglandin F2 alpha induces cardiac myocyte hypertrophy in vitro and cardiac growth in vivo. Am J Physiol. 1996; 271: H2197–H2208.[Medline] [Order article via Infotrieve]
39. Weber DR, Stroud ED, Prescott SM. Arachidonate metabolism in cultured fibroblasts derived from normal and infarcted canine heart. Circ Res. 1989; 65: 671–683.
40. Frimm CD, Sun Y, Weber KT. Wound healing following myocardial infarction in the rat: role for bradykinin and prostaglandins. J Mol Cell Cardiol. 1996; 28: 1279–1285.[CrossRef][Medline] [Order article via Infotrieve]
41. Sugimoto Y, Narumiya S, Ichikawa A. Distribution and function of prostanoid receptors: studies from knockout mice. Prog Lipid Res. 2000; 39: 289–314.[CrossRef][Medline] [Order article via Infotrieve]
42. Bhattacharya M, Peri K, Ribeiro-da-Silva A, Almazan G, Shichi H, Hou X, Varma DR, Chemtob S. Localization of functional prostaglandin E2 receptors EP3 and EP4 in the nuclear envelope. J Biol Chem. 1999; 274: 15719–15724.
43. Bhattacharya M, Peri KG, Almazan G, Ribeiro-da-Silva A, Shichi H, Durocher Y, Abramovitz M, Hou X, Varma DR, Chemtob S. Nuclear localization of prostaglandin E2 receptors. Proc Natl Acad Sci U S A. 1998; 95: 15792–15797.
44. Luttrell LM, Hawes BE, van Biesen T, Luttrell DK, Lansing TJ, Lefkowitz RJ. Role of c-Src tyrosine kinase in G protein-coupled receptor- and Gß
subunit-mediated activation of mitogen-activated protein kinases. J Biol Chem. 1996; 271: 19443–19450.
45. Yamazaki T, Komuro I, Zou Y, Kudoh S, Shiojima I, Hiroi Y, Mizuno T, Aikawa R, Takano H, Yazaki Y. Norepinephrine induces the raf-1 kinase/mitogen-activated protein kinase cascade through both alpha 1- and beta-adrenoceptors. Circulation. 1997; 95: 1260–1268.
46. Zou Y, Komuro I, Yamazaki T, Kudoh S, Uozumi H, Kadowaki T, Yazaki Y. Both Gs and Gi proteins are critically involved in isoproterenol-induced cardiomyocyte hypertrophy. J Biol Chem. 1999; 274: 9760–9770.
47. Molkentin JD. Calcineurin and beyond: cardiac hypertrophic signaling. Circ Res. 2000; 87: 731–738.
48. Hefti MA, Harder BA, Eppenberger HM, Schaub MC. Signaling pathways in cardiac myocyte hypertrophy. J Mol Cell Cardiol. 1997; 29: 2873–2892.[CrossRef][Medline] [Order article via Infotrieve]
This article has been cited by other articles:
 |
|
 |
|
  N. Yoshikawa, M. Nagasaki, M. Sano, S. Tokudome, K. Ueno, N. Shimizu, S. Imoto, S. Miyano, M. Suematsu, K. Fukuda, et al. Ligand-based gene expression profiling reveals novel roles of glucocorticoid receptor in cardiac metabolism Am J Physiol Endocrinol Metab, June 1, 2009; 296(6): E1363 - E1373. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Meyer-Kirchrath, M. Martin, C. Schooss, C. Jacoby, U. Flogel, A. Marzoll, J. W. Fischer, J. Schrader, K. Schror, and T. Hohlfeld Overexpression of prostaglandin EP3 receptors activates calcineurin and promotes hypertrophy in the murine heart Cardiovasc Res, February 1, 2009; 81(2): 310 - 318. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Degousee, S. Fazel, D. Angoulvant, E. Stefanski, S.-C. Pawelzik, M. Korotkova, S. Arab, P. Liu, T. F. Lindsay, S. Zhuo, et al. Microsomal Prostaglandin E2 Synthase-1 Deletion Leads to Adverse Left Ventricular Remodeling After Myocardial Infarction Circulation, April 1, 2008; 117(13): 1701 - 1710. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-Y. Qian, P. Harding, Y. Liu, E. Shesely, X.-P. Yang, and M. C. LaPointe Reduced Cardiac Remodeling and Function in Cardiac-Specific EP4 Receptor Knockout Mice With Myocardial Infarction Hypertension, February 1, 2008; 51(2): 560 - 566. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Testa, B. Rocca, L. Spath, F. O. Ranelletti, G. Petrucci, G. Ciabattoni, F. Naro, S. Schiaffino, M. Volpe, and C. Reggiani Expression and activity of cyclooxygenase isoforms in skeletal muscles and myocardium of humans and rodents J Appl Physiol, October 1, 2007; 103(4): 1412 - 1418. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. M. Bamman Take two NSAIDs and call on your satellite cells in the morning J Appl Physiol, August 1, 2007; 103(2): 415 - 416. [Full Text] [PDF]
|
|
|
|
 |
|
 N. Degousee, D. Angoulvant, S. Fazel, E. Stefanski, S. Saha, K. Iliescu, T. F. Lindsay, J. E. Fish, P. A. Marsden, R.-K. Li, et al. c-Jun N-terminal Kinase-mediated Stabilization of Microsomal Prostaglandin E2 Synthase-1 mRNA Regulates Delayed Microsomal Prostaglandin E2 Synthase-1 Expression and Prostaglandin E2 Biosynthesis by Cardiomyocytes J. Biol. Chem., June 16, 2006; 281(24): 16443 - 16452. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-Y. Qian, A. Leung, P. Harding, and M. C. LaPointe PGE2 stimulates human brain natriuretic peptide expression via EP4 and p42/44 MAPK Am J Physiol Heart Circ Physiol, May 1, 2006; 290(5): H1740 - H1746. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Shinmura, K. Tamaki, T. Sato, H. Ishida, and R. Bolli Prostacyclin attenuates oxidative damage of myocytes by opening mitochondrial ATP-sensitive K+ channels via the EP3 receptor Am J Physiol Heart Circ Physiol, May 1, 2005; 288(5): H2093 - H2101. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Mendez and M. C. LaPointe PGE2-induced hypertrophy of cardiac myocytes involves EP4 receptor-dependent activation of p42/44 MAPK and EGFR transactivation Am J Physiol Heart Circ Physiol, May 1, 2005; 288(5): H2111 - H2117. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Giannico, M. Mendez, and M. C. LaPointe Regulation of the membrane-localized prostaglandin E synthases mPGES-1 and mPGES-2 in cardiac myocytes and fibroblasts Am J Physiol Heart Circ Physiol, January 1, 2005; 288(1): H165 - H174. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. C. LaPointe, M. Mendez, A. Leung, Z. Tao, and X.-P. Yang Inhibition of cyclooxygenase-2 improves cardiac function after myocardial infarction in the mouse Am J Physiol Heart Circ Physiol, April 1, 2004; 286(4): H1416 - H1424. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Mendez and M. C. LaPointe PPAR{gamma} Inhibition of Cyclooxygenase-2, PGE2 Synthase, and Inducible Nitric Oxide Synthase in Cardiac Myocytes Hypertension, October 1, 2003; 42(4): 844 - 850. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Sadoshima Novel AT1 Receptor-Independent Functions of Losartan Circ. Res., April 19, 2002; 90(7): 754 - 756. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||