Published online before print January 22, 2008, doi: 10.1161/HYPERTENSIONAHA.107.091181
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(Hypertension. 2008;51:689.)
© 2008 American Heart Association, Inc.
Original Articles |
ACE Activity Is Modulated by Kinin B2 Receptor
From the Department of Biophysics (R.A.S., P.B.G., L.F., F.C.G.R., P.A.B., M.A.M., A.N., A.M.H., E.L.S., A.K.C., J.B.P.), Nephrology Division, Department of Medicine (M.C.C.A., D.E.C.), and Department of Psychobiology (J.R.C.), Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil; the Department of Physiology and Biophysics (J.L.P.), Federal University of Minas Gerais, Belo Horizonte, Brazil; and the Molecular Biology of Peptide Hormones Group (M.B.), Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Correspondence to João B. Pesquero, Department of Biophysics, Escola Paulista de Medicina, Federal University of São Paulo, 04023-062 São Paulo, Brazil. E-mail jbpesq{at}biofis.epm.br
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Abstract |
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Angiotensin-converting enzyme (ACE) is an ectoprotein able to modulate the activity of a plethora of compounds, among them angiotensin I and bradykinin. Despite several decades of research, new aspects of the mechanism of action of ACE have been elucidated, expanding our understanding of its role not only in cardiovascular regulation but also in different areas. Recent findings have ascribed an important role for ACE/kinin B2 receptor heterodimerization in the pharmacological properties of the receptor. In this work, we tested the hypothesis that this interaction also affects ACE enzymatic activity. ACE catalytic activity was analyzed in Chinese hamster ovary cell monolayers coexpressing the somatic form of the enzyme and the receptor coding region using as substrate the fluorescence resonance energy transfer peptide Abz-FRK(Dnp)P-OH. Results show that the coexpression of the kinin B2 receptor leads to an augmentation in ACE activity. In addition, this effect could be blocked by the B2 receptor antagonist icatibant. The hypothesis was also tested in endothelial cells, a more physiological system, where both proteins are naturally expressed. Endothelial cells from genetically ablated kinin B2 receptor mice showed a decreased ACE activity when compared with wild-type mice cells. In summary, this is the first report showing that the ACE/kinin B2 receptor interaction modulates ACE activity. Taking into account the interplay among ACE, ACE inhibitors, and kinin receptors, we believe that these results will shed new light into the arena of the controversial search for the mechanism controlling these interactions.
Key Words: ACE • kinin B2 receptor • dimerization • enzyme activity • ACE inhibitors • icatibant
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Introduction |
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Angiotensin-converting enzyme (ACE) is a transmembrane zinc metallopeptidase that cleaves carboxy-terminal dipeptides from several substrates and is abundant in vascular endothelial cells.1,2 An ACE soluble form found in plasma is derived from the membrane-bound form by shedding.3,4 ACE plays a major role in regulating cardiovascular functions, because it converts the decapeptide angiotensin (Ang) I into the vasoconstrictor and proliferative octapeptide Ang II and inactivates the vasodilatory nonapeptide bradykinin (BK).5 The enzyme also hydrolyzes other substrates like angiotensin 1-7, Ac-SDKP, substance P, cholecystokinin, hemopressin, and amyloid β-protein (reviewed by Reference 6). ACE inhibition is a valuable therapy for the management of hypertension and cardiac failure. Several data support the proposal that many effects of ACE inhibitors are because of the inhibition of Ang II generation.7 However, accumulating evidence indicates that several antihypertensive and cardioprotective effects of ACE inhibitors may be because of reduced BK degradation, with resultant increased endogenous BK levels.8,9 Numerous studies suggest that these compounds not only facilitate the accumulation of locally formed BK but also directly affect kinin B2 receptor signaling, resulting in an enhanced response to BK. For instance, ACE inhibitors enhance BK-mediated effects in the presence of subthreshold kinin concentrations and amplify the BK-induced response in the presence of an ACE-resistant B2 receptor agonist.10,11 In addition, ACE inhibitors are believed to stabilize the B2 receptor in a high-affinity state,12 thereby preventing and/or reversing the BK-induced sequestration to caveolae before internalization.13 Minshall et al12 have suggested that ACE inhibitors augment the BK effects on the receptor by inducing a cross-talk between ACE and the kinin B2 receptor at the membrane; however, this is still controversial. In addition, it has been proposed that this indirect activation might depend on the steric relationship of the enzyme to the receptor, because ACE has to be in the immediate vicinity of the receptor for the activation to occur, possibly because of heterodimer formation.14,15
Despite the large number of studies describing the potentiation of BK effects by ACE inhibitors, information about a possible modulation of ACE activity by kinin receptors was never in focus, according to our knowledge. Therefore, the present study was addressed to investigate a possible role of kinin receptor expression on ACE catalytic activity. We have explored this possibility in transfected Chinese hamster ovary (CHO) cells expressing ACE or ACE and kinin B2 receptors using the fluorescence resonance energy transfer peptide Abz-FRK(Dnp)P-OH.16 In addition, native endothelial cells from wild-type (WT) and kinin B2 receptor knockout mice were also analyzed to evaluate the influence of kinin receptors on ACE activity in a physiological system. Our findings show for the first time that kinin B2 receptor expression positively modulated ACE activity, showing further evidence of an interaction among kinin B2 receptor and ACE molecules.
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Materials and Methods |
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Materials
If not otherwise indicated, all of the reagents were purchased from Sigma, and cell culture media and supplements were purchased from Gibco-BRL.
Animals
Experiments were carried out with kinin B2 receptor knockout mice (B2–/–),17 and C57Bl/6 animals (Taconic) were used as controls. Animals were obtained from the Centro de Desenvolvimento de Modelos Experimentais para a Medicina e Biologia at the Federal University of São Paulo. All of the experiments reported were conducted as stated in the National Institutes of Health Guide for the Care and Use of Laboratory Animals and approved by a local animal care and use committee. Animals were maintained on standard mouse chow at 22°C on a 12-hour light-dark cycle and allowed ad libitum access to food and tap water.
Expression of B2 Receptor in Transfected CHO Cells
CHO cells were cultured according to Sabatini et al.18 Briefly, cells were previously transfected with a plasmid carrying the somatic form of the rat ACE coding region (using neomycin resistance gene for selection), and individual clones were screened for ACE activity. Clones were then stably transfected either with the empty pcDNA3 plasmid (mock-transfected cells) or with the plasmid containing the rat B2 receptor coding region using LipofectAMINE 2000. After transfection, cells were selected in Ham’s F-12 medium containing 0.5 mg/mL of hygromycin B, and resistant clones were propagated. Clones with high expression levels of B2 receptors mRNA were selected by real-time PCR. Total RNA (750 ng) was reverse-transcribed using Moloney murine leukemia virus (Invitrogen) to cDNA according to the manufacturer’s instructions. The reaction product was amplified by real-time PCR on the 7000 Sequence Detection System (ABI Prism, Applied Biosystems) using the TaqMan Universal PCR Master Mix (Applied Biosystems). The thermal cycling conditions were composed by an initial denaturation step of 95°C for 10 minutes, 50 cycles at 95°C for 15 seconds, and 60°C for 1 minute. Experiments were performed in triplicate for each data point. B2 receptor mRNA abundance was quantified as a relative value compared with an internal reference, β-actin, of which the abundance was assumed not to change between the varying experimental conditions. Primers used for real-time PCR were as follows: murine B2 receptor (GenBank accession No. NM009747), forward primer 5'-CCCTTCCTCTGGGTCCTCTT-3' and reverse primer 5'-GAAGAACACGCTGAGGACAAAGA-3'; 6-carboxyfluorescein probe, 5'-CCGCACTGGAGAAC-3'; murine β-actin (GenBank accession No. NM007393), forward primer 5'-CTGGCCTCACTGTCCACCTT-3' and reverse primer 5'-CGGACTCATCGTACTCCTGCTT-3'; and 6-carboxyfluorescein probe, 5'-CTGATCCACATCTGCT-3'. B2 receptor and β-actin mRNA expression were obtained from the cycle threshold (Ct) associated with the exponential growth of the PCR products. Quantitative values for B2 receptor mRNA expression were obtained by the parameter 2–
Ct, in which Ct represents the subtraction of the β-actin Ct values from the B2 values.
Expression of ACE mRNA in B2–/– Endothelial Cells
ACE and β-actin mRNA expression in WT and B2–/– endothelial cells were assessed by SYBR Green real-time PCR using 25 ng of total cDNA, SYBR Green Universal Master Mix (Applied Biosystems), and the following set of primers independently: ACE (5'-CTCAGCCTGGGACTTCTACAAC-3'; 5'-CTCCATGTTCACAGAGGTACACT-3'; GenBank accession No. NM_207624.2) and β-actin (5'-CTGGCCTCACTGTCCACCTT-3', 5'-CGGACTCATCGTACTCCTGCTT-3'; GenBank accession No. NM_007393.1). The thermal cycling conditions and the data analysis were performed as described by the TaqMan real-time PCR. Standard and melting curves were performed in parallel to check reaction efficiency and specificity, respectively.
Binding Assay
Binding assays in CHO cells expressing B2 receptors or coexpressing ACE and B2 receptors were performed according to Santos et al,19 at 4°C in a 1-mL assay volume and initiated by the addition of 50 pM of 125I-Tyr0-BK and increasing concentrations (10–12 to 10–6 mol/L) of nonradioactive BK as a competitor. BK measurements were done in duplicate. The competition binding profiles were analyzed by nonlinear regression analysis using Prism 3.02 (GraphPad Software), and Bmax values were calculated according to DeBlasi et al.20
Functional Assays
The Cytosensor microphysiometer (Molecular Devices) was used to measure the acidification rate in the extracellular microenvironment because of cellular metabolic activity.19,21 CHO cells expressing the receptor and coexpressing ACE/B2 were plated into capsule polycarbonate cups at a density of 5x105 cells per cup in DMEM, 
12 to 16 hours before the experiment, according to Santos et al.19 To assess shifts in the extracellular acidification rate, cells were stimulated (over a period of 30 seconds) with BK (10–12 to 10–5 mol/L) in the presence or absence of 2.5 µmol/L of lisinopril. Measurements were done in quadruplicate, and the generated concentration-response curves were analyzed by nonlinear regression analysis using GraphPad Software (GraphPad).
Primary Endothelial Cell Culture
Microvascular endothelial cells from pulmonary vascular beds were cultured as described by Chen et al22 WT and B2–/– mice were euthanized by cervical dislocation and exsanguinated by cutting the bilateral carotid arteries. The lungs were isolated, and the blood remaining in the pulmonary vessels was washed with PBS. The tissues of the lung surface were cut into small pieces separately. Pieces were placed into cell culture dishes (35 mm) and cultured in DMEM supplemented with 20% FBS containing 40 mg/L of gentamicin. After a 48-hour culture, the tissues were discarded. The medium was changed every 48 hours, and cells were subcultured between the days 6 and 8 by harvesting with trypsin-EDTA. Semiconfluent (80–90%) cells were used until the fifth passage.
Measurement of ACE Activity in Transfected CHO and Endothelial Cells
ACE activity in CHO cells was performed according to Sabatini et al.18 The endothelial cells were plated in 6-well plates (Corning) at 1.5x105 cells per well, washed with Hanks’ balanced salt solution buffer containing 10 µmol/L of ZnCl2 (pH 7.4) and incubated in the same buffer with 10 µmol/L of Abz-FRK(Dnp)P-OH. Aliquots of culture supernatant were collected in different times (0 to 40 minutes), the reaction stopped at 0°C, and the fluorescence produced by the hydrolysis of the substrate by ACE determined as described above. The arbitrary fluorescence units were converted into micromoles of substrate hydrolyzed based on a calibration curve obtained using a standard solution of complete hydrolyzed substrate.18,23 ACE activity was inhibited by 2.5 µmol/L of the specific ACE inhibitor lisinopril used as a control in the assays. ACE shedding was not observed in the time period of our assays.18 The protein content of each well was determined by the method of Lowry et al24 using BSA as standard. Measurements were performed in triplicate, and ACE activity values were reported as micromoles of substrate hydrolyzed per minute per milligram of protein (µmol · min–1 · mg–1), represented as 1 unit.
ACE Protein Expression in Transfected CHO Cells
Protein expression was determined by Western blotting analysis. Subcellular fractionation was performed according to Bogan et al.25 Cell extracts were separated by SDS-PAGE (10%) and transferred to a polyvinylidene fluoride membrane. The membranes were blocked for 60 minutes in Tris-buffered saline Tween containing 5% nonfat milk. The immunoblot was performed with an anti–ACE-specific primary antibody (anti-ACE, clone 3C5, Chemicon, Millipore Corporation) 1:1000 dilution, overnight at 4°C, followed by the membrane incubation for 2 hours at room temperature with a secondary antibody (Stabilized goat anti-mouse horseradish peroxidase–conjugated, Pierce, Thermo Fisher Scientific Inc). The internal control was measured by membrane incubation with GAPDH antibody (anti-GAPDH rabbit monoclonal antibody, Cell Signaling) 1:2000 at 4°C overnight, followed by the incubation with the secondary antibody (stabilized goat anti-rabbit horseradish peroxidase–conjugated, Pierce, Thermo Fisher Scientific Inc) for 2 hours at room temperature. The immunoreactive bands were visualized with the chemiluminescence reagent Super Signal West Dura for the chemiluminescent detection of horseradish peroxidase on Western blotting (Pierce), according to the procedure described by the supplier.
Statistics
Differences of data among groups in individual experiments were analyzed for statistical significance by 1-way ANOVA, followed by the Bonferroni test. A value of P<0.05 was considered significant.
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Results |
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ACE and Kinin B2 Receptor Expression in Transfected CHO Cells
CHO cells were permanently transfected initially with the plasmid containing the coding region for the somatic ACE. ACE expression was evaluated by RT-PCR and Western blot,18 and one clone expressing the enzyme in high amounts was selected and transfected either with an empty plasmid (mock-transfected cells) or with the same plasmid containing the kinin B2 receptor coding region. The expression of the kinin B2 receptor gene in these cells was evaluated by real-time PCR, by radioligand binding studies, and by a functional assay in the microphysiometer cytosensor using the kinin B2 agonist BK (Figure 1). In the binding study, cells expressing only the B2 receptor or both ACE/B2 receptor in the presence of lisinopril were able to bind specifically the B2 agonist with high affinity (Figure 1B), whereas cells expressing only ACE or ACE/B2 receptor in the absence of lisinopril displayed no binding for the B2 agonist (Figure 1B). Furthermore, BK was able to elicit a concentration-response effect on the extracellular acidification rate in CHO cells expressing the B2 receptor or ACE/B2 receptor in the presence of lisinopril (Figure 1C). This effect was blocked by the specific B2 antagonist icatibant, showing the presence of a functional receptor at the membrane in both cases (data not shown). The coexpression of the receptor and the enzyme did not change the affinity of the B2 agonist BK to the receptor (Table).
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ACE Activity in CHO Cells Transfected With the Kinin B2 Receptor
By using a selective fluorescence substrate assay for ACE activity determination,23 we could evaluate ACE activity in CHO cell monolayers expressing both ACE and ACE with the B2 receptor (Figure 2). Unexpectedly, the results show that the coexpression of the kinin B2 receptor in these cells increased significantly ACE activity. Cells expressing the receptor presented ACE activity 41% higher (P<0.05) when compared with the cells expressing only ACE. The specificity of the assay was demonstrated by the complete inhibition of the catalytic activity in the presence of 2.5 µmol/L of lisinopril (data not shown). Furthermore, the antagonist icatibant could lower the increase in ACE activity induced by coexpression of the kinin B2 receptor (Figure 2). On the other hand, the B1 antagonist DesArg9-Leu8-BK used at a high concentration (10–6 mol/L) did not change ACE activity, and the B2 antagonist had no effect in CHO cells expressing only the enzyme (Figure 2). Because the level of ACE expression could vary in transfected cells, and this level would evidently interfere with the enzyme activity, we evaluated the levels of ACE by Western blot. Western blot analysis showed that the coexpression of the B2 receptor with ACE did not significantly alter the amount of ACE expressed in the cells, taking into account total protein (Figure 3A) or membrane fraction protein (Figure 3B), when compared with the mock-transfected cells.
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Influence of B2 Receptor on ACE Activity in Endothelial Cells
To prove the hypothesis that the kinin B2 receptor could directly interact with ACE and modulate the enzyme activity in a more physiological environment, endothelial cells obtained from lungs of WT and kinin B2 receptor knockout mice were cultured and analyzed for ACE activity. Results show that cells from WT mice, expressing both ACE and the B2 receptor, possess higher ACE activity (Figure 4A) without ACE mRNA (Figure 4B) or ACE protein (Figure 4C) alterations, when compared with the activity obtained in cells from the B2 knockout mice. In addition, icatibant could partially inhibit ACE activity significantly in endothelial cells obtained from WT but not in the ones obtained from the B2 knockout animals (Figure 4A).
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Discussion |
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ACE is a multisubstrate peptidyl-dipeptidase known to interfere with different systems involved in cardiovascular regulation, inflammation, pain, glucose homeostasis, and angiogenesis, among others. Ang I and BK, classic substrates for ACE, are converted to Ang II and hydrolyzed to inactive peptides, respectively, and have opposing effects in most systems. These agonists promote their effects by activation of specific G protein–coupled receptors (Ang II type 1 and Ang II type 2 for Ang II and B1 and B2 for BK). The interaction of ACE with Ang I and kinin B2 receptors has been extensively described in the literature.11,14,26–30 These studies also show that this interaction is able to alter the pharmacological profile of these receptors. In addition, it is known that ACE inhibitors can directly bind and activate kinin B1 receptors.31,32 Despite the long-held view that G protein–coupled receptors function as monomeric signaling units (ie, a single receptor couples to a G protein on ligand binding), a growing body of evidence suggests that these receptors form higher oligomeric structures through direct interactions among either identical or nonidentical family members.33,34 Recently, Chen et al35 have successfully shown heterodimer formation between the ACE and B2 receptor and colocalization of both proteins at the plasma membrane. However, the underlying mechanisms involved in receptor oligomerization and the exact role of this phenomenon in G protein–coupled receptor function remain largely unknown. In the present article we investigated the occurrence of ACE/B2 receptor interaction from a completely different aspect: we reasoned that this interaction between both proteins could lead to an alteration in ACE catalytic activity. Therefore, this hypothesis that takes into account the cross-talk between ACE and the kinin B2 receptor was analyzed basically by 2 different approaches: one using an artificial system, where CHO cells were transfected with both ACE and the B2 receptor and another one where a natural system expressing both proteins, like lung endothelial cells, was used. Our results using both systems show that the presence of the kinin B2 receptor can significantly increase ACE activity toward Abz-FRK(Dnp)P-OH and that the specific blockade of the receptor is sufficient to cause inhibition of the enzyme, demonstrating that antagonist occupancy of the B2 receptor negatively affects ACE catalytic activity toward this substrate. In accordance with this hypothesis, previous data from our laboratory36 show that deletion of the kinin B1 receptor in mice leads to an inhibition of ACE activity in stomach fundus. This finding was evidenced by the lack of the potentiating effect of captopril on the contractile responses to BK in this preparation, indicating a potential modulation of ACE activity by kinin B1 receptors. However, quantitative analysis of enzymatic activity in transfected cells is a difficult task. This analysis should take into account the level of protein expression, which can vary in transfected cells depending on transfection efficiency, and this level can evidently interfere with the enzyme activity. Therefore, to avoid transfection efficiency bias, we cotransfected the kinin B2 receptor on primarily ACE-transfected CHO cells.18 In addition, the levels of ACE in the cotransfected cells were also evaluated by Western blot and were shown not to differ significantly from the levels from those cells expressing only ACE. Therefore, we could rule out an alteration on ACE activity exclusively based on expression levels. Furthermore, we also evaluated the density of B2 receptors in the membrane of transfected CHO cells by binding assays. Although the initial amount of DNA used in the transfection assays was similar, we could observe a higher number of binding sites of B2 receptors in cells expressing only the kinin receptors (420 fmol/mg of protein) when compared with that coexpressing ACE and B2 receptors (26 fmol/mg of protein). Higher values of B2 receptor binding sites were also shown by Minshall et al12 in CHO cells similarly transfected with the B2 receptor (900 to 1250 fmol/mg of protein) in comparison with cells transfected with both ACE and the B2 receptor (303 to 753 fmol/mg of protein). However, despite this variation in receptor density, the affinity of the agonist for the receptor was not altered, as shown by radioligand binding. Furthermore, the functionality of the B2 receptor in the transfected cells was evaluated by the Cytosensor microphysiometer, evidencing the correct expression and functionality of these receptors at the cellular membrane.
A complex formation between ACE and the B2 receptor is thought to be a bimolecular reaction, with the kinetics dependent on the reagents concentration. However, despite the low concentration of the B2 receptor in our cells, determined by the binding assay, the effect of icatibant on ACE activity shows that B2 receptor concentration in our system is enough for the complex to be mounted and functional. Thus, our data bring new evidence to support a functional interaction between ACE and the B2 receptor. One striking result shown in the present work was the inhibitory effect of the kinin B2–specific antagonist icatibant on ACE activity. According to our findings, it can be inferred that binding of this molecule to the kinin B2 receptor suggests the communication between ACE and B2 receptor. This assumption is corroborated by the fact that the incubation of the cells only expressing ACE with icatibant did not result in alteration in the activity of the enzyme. In addition, incubation of icatibant with the soluble ACE present in plasma was not able to interfere with the enzyme activity.37 Furthermore, it is described that icatibant is highly stable against enzymatic degradation, not being a competitive substrate for ACE type kininase II.38,39
Although the molecular mechanism by which the B2 receptor regulates the activity of ACE is not fully elucidated, some possibilities may be suggested. Because icatibant, a selective kinin B2 receptor antagonist, is able to interfere in ACE activity, one possible mechanism by which B2 receptor could regulate this activity is by dimerization between both proteins. This hypothesis is corroborated by the fact that both proteins colocalize and generate functional heterodimers.14,35
The physiological relevance of our findings is still not evident but could be related to the control of BK and Ang II levels, 2 potent and antagonizing peptides, where both ACE an the kinin B2 receptor proteins are expressed. Thus, interaction between these proteins may contribute to the potentiation of angiotensin II effects in some tissues. Furthermore, this mechanism may act as a negative feedback to reduce BK formation after B2 receptor stimulation. Despite the fact that the specificity of the assay has been confirmed by the complete inhibition of the hydrolysis of Abz-FRK(Dnp)P-OH by the specific ACE inhibitor lisinopril, the modulation in ACE activity by the B2 receptor should be further studied with the physiological agonists Ang I and BK.
Perspectives
Thus, considering the physiological relevance of ACE and the role of its inhibitors in the clinic, we believe that these results will highlight the interplay between these molecules and kinin receptors and will help us to understand the mechanism controlling these interactions.
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Acknowledgments |
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Sources of Funding
This work was supported by grants from the São Paulo State Research Foundation (FAPESP, 02/00807-7) and from the Brazilian National Research Council (CNPq, 520012/02-0). R.A.S., M.A.M., and E.L.S. were supported by postdoctoral fellowships from Probral CAPES/DAAD (239/06).
Disclosures
None.
Received March 20, 2007; first decision April 12, 2007; accepted December 19, 2007.
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References |
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1. Gohlke P, Bunning P, Unger T. Distribution and metabolism of angiotensin I and II in the blood vessel wall. Hypertension. 1992; 20: 151–157.
2. Arnal JF, Battle T, Rasetti C, Challah M, Costerousse O, Vicaut E, Michel JB, Alhenc-Gelas F. ACE in three tunicae of rat aorta: expression in smooth muscle and effect of renovascular hypertension. Am J Physiol. 1994; 267: H1777–H1784.[Medline] [Order article via Infotrieve]
3. Erdos EG, Skidgel RA. Renal metabolism of angiotensin I and II. Kidney Int. 1990; 30 (suppl): S24–S27.
4. Woodman ZL, Schwager SL, Redelinghuys P, Chubb AJ, van der Merwe EL, Ehlers MR, Sturrock ED. Homologous substitution of ACE C-domain regions with N-domain sequences: effect on processing, shedding, and catalytic properties. Biol Chem. 2006; 387: 1043–1051.[CrossRef][Medline] [Order article via Infotrieve]
5. Yang HY, Erdos EG, Levin Y. Characterization of a dipeptide hydrolase (kininase II: angiotensin I converting enzyme). J Pharmacol Exp Ther. 1971; 177: 291–300.
6. Fleming I. Signaling by the angiotensin-converting enzyme. Circ Res. 2006; 98: 887–896.
7. Unger T, Gohlke P, Gruber M-G. Converting enzyme inhibitors. In: Ganten D, Mulrow PJ, eds. Pharmacology of Antihypertensive Therapeutics. Handbook of Experimental Pharmacology. Berlin, Germany: Springer-Verlag; 1990: 377–481.
8. Linz W, Wiemer G, Gohlke P, Unger T, Scholkens BA. Contribution of kinins to the cardiovascular actions of angiotensin-converting enzyme inhibitors. Pharmacol Rev. 1995; 47: 25–49.[Abstract]
9. Dendorfer A, Wolfrum S, Dominiak P. Pharmacology and cardiovascular implications of the kinin-kallikrein system. J Pharmacol. 1999; 79: 403–426.
10. Hecker M, Porsti I, Bara AT, Busse R. Potentiation by ACE inhibitors of the dilator response to bradykinin in the coronary microcirculation: interaction at the receptor level. Br J Pharmacol. 1994; 111: 238–244.[Medline] [Order article via Infotrieve]
11. Minshall RD, Erdos EG, Vogel SM. Angiotensin I-converting enzyme inhibitors potentiate bradykinin’s inotropic effects independently of blocking its inactivation. Am J Cardiol. 1997; 80: 132A–136A.[CrossRef][Medline] [Order article via Infotrieve]
12. Minshall RD, Tan F, Nakamura F, Rabito SF, Becker RP, Marcic B, Erdos EG. Potentiation of the actions of bradykinin by angiotensin I-converting enzyme inhibitors. The role of expressed human bradykinin B2 receptors and angiotensin I-converting enzyme in CHO cells. Circ Res. 1997; 81: 848–856.
13. Haasemann M, Cartaud J, Muller-Esterl W, Dunia I. Agonist-induced redistribution of bradykinin B2 receptor in caveolae. J Cell Sci. 1998; 111: 917–928.[Abstract]
14. Marcic B, Deddish PA, Skidgel RA, Erdos EG, Minshall RD, Tan F. Replacement of the transmembrane anchor in angiotensin I-converting enzyme (ACE) with a glycosylphosphatidylinositol tail affects activation of the B2 bradykinin receptor by ACE inhibitors. J Biol Chem. 2000; 275: 16110–16118.
15. Marcic B, Deddish PA, Jackman HL, Erdos EG, Tan F. Effects of the N-terminal sequence of ACE on the properties of its C-domain. Hypertension. 2000; 36: 116–121.[Medline] [Order article via Infotrieve]
16. Araujo MC, Melo RL, Cesari MH, Juliano MA, Juliano L, Carmona AK. Peptidase specificity characterization of C- and N-terminal catalytic sites of angiotensin I-converting enzyme. Biochemistry. 2000; 39: 8519–8525.[CrossRef][Medline] [Order article via Infotrieve]
17. Borkowski JA, Ransom RW, Seabrook GR, Trumbauer M, Chen H, Hill RG, Strader CD, Hess JF. Targeted disruption of a B2 bradykinin receptor gene in mice eliminates bradykinin action in smooth muscle and neurons. J Biol Chem. 1995; 270: 13706–13710.
18. Sabatini RA, Bersanetti PA, Farias SL, Juliano L, Juliano MA, Casarini DE, Carmona AK, Paiva AC, Pesquero JB. Determination of angiotensin I-converting enzyme activity in cell culture using fluorescence resonance energy transfer peptides. Anal Biochem. 2007; 15: 255–262.
19. Santos EL, Pesquero JB, Oliveira L, Paiva AC, Costa-Neto CM. Mutagenesis of the AT1 receptor reveals different binding modes of angiotensin II and [Sar1]-angiotensin II. Regul Pept. 2004; 119: 183–188.[CrossRef][Medline] [Order article via Infotrieve]
20. DeBlasi A, O’Reilly K, Motulsky HJ. Calculating receptor number from binding experiments using same compound as radioligand and competitor. Trends Pharmacol Sci. 1989; 10: 227–229.[CrossRef][Medline] [Order article via Infotrieve]
21. Santos EL, Reis RI, Silva RG, Shimuta SI, Pecher C, Bascands JL, Schanstra JP, Oliveira L, Bader M, Paiva AC, Costa-Neto CM, Pesquero JB. Functional rescue of a defective angiotensin II AT(1) receptor mutant by the Mas protooncogene. Regul Pept. 2007; 141: 159–167.[CrossRef][Medline] [Order article via Infotrieve]
22. Chen SF, Fei X, Li SH. A new simple method for isolation of microvascular endothelial cells avoiding both chemical and mechanical injuries. Microvasc Res. 1995; 50: 119–128.[CrossRef][Medline] [Order article via Infotrieve]
23. Carmona AK, Schwager SL, Juliano MP, Juliano L, Sturrock ED. A continous fluorescence resonance energy transfer (FRET) angiotensin I-converting enzyme assay. Nature Protocols. 2006; 1: 1971–1976.[CrossRef][Medline] [Order article via Infotrieve]
24. Lowry OH, Rosebrough NJ, Farr AI, Randall RJ. Protein measurement with the Folin phenol reagent. Biol Chem. 1951; 193: 265–275.
25. Bogan JS, McKee AE, Lodish HF. Insulin-responsive compartments containing GLUT4 in 3T3-L1 and CHO cells: regulation by amino acid concentrations. Mol Cell Biol. 2001; 21: 4785–4806.
26. Erdos EG, Deddish PA, Marcic BM. Potentiation of bradykinin actions by ACE inhibitors. Trends Endocrinol Metab. 1999; 10: 223–229.[CrossRef][Medline] [Order article via Infotrieve]
27. Erdos EG, Jackman HL, Brovkovych V, Tan F, Deddish PA. Products of angiotensin I hydrolysis by human cardiac enzymes potentiate bradykinin. J Mol Cell Cardiol. 2002; 34: 1569–1576.[CrossRef][Medline] [Order article via Infotrieve]
28. Tom B, Dendorfer A, de Vries R, Saxena PR, Jan Danser AH. Bradykinin potentiation by ACE inhibitors: a matter of metabolism. Br J Pharmacol. 2002; 137: 276–284.[CrossRef][Medline] [Order article via Infotrieve]
29. Marcic B, Deddish PA, Jackman HL, Erdos EG. Enhancement of bradykinin and resensitization of its B2 receptor. Hypertension. 1999; 33: 835–843.
30. Minshall RD, Nedumgottil SJ, Igic R, Erdos EG, Rabito SF. Potentiation of the effects of bradykinin on its receptor in the isolated guinea pig ileum. Peptides. 2000; 21: 1257–1264.[CrossRef][Medline] [Order article via Infotrieve]
31. Ignjatovic T, Tan F, Brovkovych V, Skidgel RA, Erdos EG. Novel mode of action of angiotensin I converting enzyme inhibitors: direct activation of bradykinin B1 receptor. J Biol Chem. 2002; 277: 16847–16852.
32. Ignjatovic T, Tan F, Brovkovych V, Skidgel RA, Erdos EG. Activation of bradykinin B1 receptor by ACE inhibitors. Int Immunopharmacol. 2002; 2: 1787–1793.[CrossRef][Medline] [Order article via Infotrieve]
33. Bouvier M. Oligomerization of G-protein-coupled transmitter receptors. Nat Rev Neurosci. 2001; 2: 274–286.[CrossRef][Medline] [Order article via Infotrieve]
34. Jordan BA, Devi LA. G-protein-coupled receptor heterodimerization modulates receptor function. Nature. 1999; 399: 697–700.[CrossRef][Medline] [Order article via Infotrieve]
35. Chen Z, Deddish PA, Minshall RD, Becker RP, Erdos EG, Tan F. Human ACE and bradykinin B2 receptors form a complex at the plasma membrane. FASEB J. 2006; 20: 2261–2270.
36. Barbosa AM, Felipe SA, Pesquero JB, Paiva AC, Shimuta SI. Disruption of the kinin B1 receptor gene affects potentiating effect of captopril on BK-induced contraction in mice stomach fundus. Peptides. 2006; 27: 3377–3382.[CrossRef][Medline] [Order article via Infotrieve]
37. Keidar S, Attias J, Coleman R, Wirth K, Scholkens B, Hayek T. Attenuation of atherosclerosis in apolipoprotein E-deficient mice by ramipril is dissociated from its antihypertensive effect and from potentiation of bradykinin. J Cardiovasc Pharmacol. 2000; 35: 64–72.[CrossRef][Medline] [Order article via Infotrieve]
38. Hock FJ, Wirth K, Albus U, Linz W, Gerhards HJ, Wiemer G, Henke S, Breipohl G, Konig W, Knolle J. Hoe 140 a new potent and long acting bradykinin-antagonist: in vitro studies. Br J Pharmacol. 1991; 102: 769–773.[Medline] [Order article via Infotrieve]
39. Wirth K, Hock FJ, Albus U, Linz W, Alpermann HG, Anagnostopoulos H, Henk S, Breipohl G, Konig W, Knolle J. Hoe 140 a new potent and long acting bradykinin-antagonist: in vivo studies. Br J Pharmacol. 1991; 102: 774–777.[Medline] [Order article via Infotrieve]
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