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Jøns C, Porta-Sánchez A, Lai PFH, Wauchop M, Massé S, Azam MA, Asta J, Rose RA, Nanthakumar K. Mechanism of and strategy to mitigate liraglutide-mediated positive chronotropy. Life Sci 2021; 282:119815. [PMID: 34256040 DOI: 10.1016/j.lfs.2021.119815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/25/2021] [Accepted: 07/05/2021] [Indexed: 11/18/2022]
Abstract
AIM An adverse side-effect of Liraglutide (LG), a Glucagon-Like Peptide 1 (GLP1)-analog commonly used in treatments for diabetes, is positive chronotropy. The goal of this study is to investigate on the mechanism of this drug-induced chronotropy and explore potential means to mitigate this side-effect so as to maximize the therapeutic benefits from LG. MAIN METHODS Experiments were conducted with: 1) Isolated rabbit hearts in a Langendorff set-up to assess for direct effects of drug actions and 2) Murine cardiomyocytes isolated from the sino-atrial node (SAN) to assess the effects of LG on spontaneous action potential (AP) firing and the hyperpolarization-activated current If. KEY FINDINGS LG induced a dose-dependent increase in heart rate. Its effects on sinus node automaticity, which were not suppressed during β-blockade with Propranolol, were abolished by If blockade with Ivabradine. In isolated murine SAN myocytes, LG increased spontaneous AP firing frequency by an increase in diastolic depolarization slope without changing other electrophysiological parameters. SIGNIFICANCE LG-induced positive chronotropy is partly due to a direct effect on the SAN and is independent of the adrenergic cascade and extrinsic autonomic reflex mechanisms. The direct LG-associated increase in heart rate should be mitigated with If blockers rather than β-blockade.
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Affiliation(s)
- Christian Jøns
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada; Department of Cardiology, The Heart Centre, Rigshospitalet, Copenhagen, Denmark
| | - Andreu Porta-Sánchez
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada; Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain and Hospital Universitario Quirónsalud, Madrid, Spain
| | - Patrick F H Lai
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | | | - Stéphane Massé
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | - Mohammed Ali Azam
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | - John Asta
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.
| | - Kumaraswamy Nanthakumar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada.
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Longo J, Pandyra AA, Stachura P, Minden MD, Schimmer AD, Penn LZ. Cyclic AMP-hydrolyzing phosphodiesterase inhibitors potentiate statin-induced cancer cell death. Mol Oncol 2020; 14:2533-2545. [PMID: 32749766 PMCID: PMC7530792 DOI: 10.1002/1878-0261.12775] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 07/13/2020] [Accepted: 07/30/2020] [Indexed: 01/06/2023] Open
Abstract
Dipyridamole, an antiplatelet drug, has been shown to synergize with statins to induce cancer cell-specific apoptosis. However, given the polypharmacology of dipyridamole, the mechanism by which it potentiates statin-induced apoptosis remains unclear. Here, we applied a pharmacological approach to identify the activity of dipyridamole specific to its synergistic anticancer interaction with statins. We evaluated compounds that phenocopy the individual activities of dipyridamole and assessed whether they could potentiate statin-induced cell death. Notably, we identified that a phosphodiesterase (PDE) inhibitor, cilostazol, and other compounds that increase intracellular cyclic adenosine monophosphate (cAMP) levels potentiate statin-induced apoptosis in acute myeloid leukemia and multiple myeloma cells. Additionally, we demonstrated that both dipyridamole and cilostazol further inhibit statin-induced activation of sterol regulatory element-binding protein 2, a known modulator of statin sensitivity, in a cAMP-independent manner. Taken together, our data support that PDE inhibitors such as dipyridamole and cilostazol can potentiate statin-induced apoptosis via a dual mechanism. Given that several PDE inhibitors are clinically approved for various indications, they are immediately available for testing in combination with statins for the treatment of hematological malignancies.
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Affiliation(s)
- Joseph Longo
- Princess Margaret Cancer CentreUniversity Health NetworkTorontoCanada
- Department of Medical BiophysicsUniversity of TorontoTorontoCanada
| | - Aleksandra A. Pandyra
- Princess Margaret Cancer CentreUniversity Health NetworkTorontoCanada
- Department of Medical BiophysicsUniversity of TorontoTorontoCanada
- Department of Molecular Medicine IIMedical FacultyHeinrich Heine UniversityDüsseldorfGermany
- Department of Gastroenterology, Hepatology, and Infectious DiseasesHeinrich Heine UniversityDüsseldorfGermany
| | - Paweł Stachura
- Department of Molecular Medicine IIMedical FacultyHeinrich Heine UniversityDüsseldorfGermany
| | - Mark D. Minden
- Princess Margaret Cancer CentreUniversity Health NetworkTorontoCanada
- Department of Medical BiophysicsUniversity of TorontoTorontoCanada
| | - Aaron D. Schimmer
- Princess Margaret Cancer CentreUniversity Health NetworkTorontoCanada
- Department of Medical BiophysicsUniversity of TorontoTorontoCanada
| | - Linda Z. Penn
- Princess Margaret Cancer CentreUniversity Health NetworkTorontoCanada
- Department of Medical BiophysicsUniversity of TorontoTorontoCanada
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Cooperation of G12/13 and Gi proteins via lysophosphatidic acid receptor-2 (LPA 2) signaling enhances cancer cell survival to cisplatin. Biochem Biophys Res Commun 2020; 532:427-432. [PMID: 32883524 DOI: 10.1016/j.bbrc.2020.08.087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 08/22/2020] [Indexed: 11/22/2022]
Abstract
Lysophosphatidic acid (LPA) through six subtypes of G protein-coupled LPA receptors (LPA1 to LPA6) mediates a variety of cancer cell functions. The aim of this study was to evaluate the cooperative effects of G12/13 and Gi proteins through LPA2 on cancer cell survival to cisplatin (CDDP). In cell survival assay, cells were treated with CDDP every 24 h for 2 days. The long-term CDDP treated (HT-CDDP) cells established from fibrosarcoma HT1080 cells were pretreated with an LPA2 agonist, GRI-977143. The cell survival rate to CDDP of HT-CDDP cells was significantly increased by GRI-977143. The elevated cell survival to CDDP was suppressed by LPA2 knockdown. Since G12/13 protein stimulates Rho-mediated signaling, RhoA and RhoC knockdown cells were generated from HT1080 cells (HT1080-RhoA and HT1080-RhoC cells, respectively). In the presence of GRI-977143, HT1080-RhoA and HT1080-RhoC cells showed the low cell survival rates to CDDP. On the other hand, Gi protein inhibits adenylyl cyclase (AC) activity. Before cell survival assay, cells were treated with a Gi protein inhibitor, pertussis toxin (PTX) for 24 h. The cell survival rate to CDDP of HT1080 cells was significantly reduced by PTX. Furthermore, when HT1080-RhoA and HT1080-RhoC cells were pretreated with PTX, the cell survival rates to CDDP of both cells were markedly inhibited by PTX. The present results suggest that cooperation of G12/13 and Gi proteins activated by LPA2 enhances the cell survival of HT1080 cells treated with CDDP.
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Ishimoto K, Minami A, Minami K, Ueda N, Tsujiuchi T. Different effects of lysophosphatidic acid receptor-2 (LPA 2) and LPA 5 on the regulation of chemoresistance in colon cancer cells. J Recept Signal Transduct Res 2020; 41:93-98. [PMID: 32672083 DOI: 10.1080/10799893.2020.1794002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Lysophosphatidic acid (LPA) is a simple physiological lipid and exhibits several biological functions by binding to G-protein-coupled LPA receptors (LPA receptor-1 (LPA1) to LPA6). The present study aimed to evaluate whether LPA signaling via LPA2 and LPA5 is involved in the chemoresistance to anticancer drugs in colon cancer DLD1 cells. In cell survival assay, cells were treated with fluorouracil (5-FU) every 24 h for 2 days. The cell survival rate to 5-FU of DLD1 cells was significantly decreased by LPA treatment. In the presence of LPA, the cell survival rate to 5-FU was significantly elevated by LPA5 knockdown. Before initiation of the cell survival assay, cells were pretreated with an LPA2 agonist, GRI-977143. The cell survival rate to 5-FU was markedly increased in DLD1 cells treated with GRI-977143. In the presence of GRI-977143, the elevated cell survival rate of DLD1 cells was reduced by LPA2 knockdown. To assess the effects of LPA2 and LPA5 on the enhancement of chemoresistance, long-term 5-FU treated (DLD-5FU) cells were generated from DLD1 cells. The cell survival rate to 5-FU of DLD-5FU cells were significantly elevated by LPA5 knockdown. GRI-977143 treatment increased the cell survival rate to 5-FU of DLD-5FU cells. These results suggest that LPA2 promotes and LPA5 suppresses the acquisition of chemoresistance in colon cancer cells treated with anticancer drugs.
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Affiliation(s)
- Kaichi Ishimoto
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, Higashiosaka, Osaka, Japan
| | - Akito Minami
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, Higashiosaka, Osaka, Japan
| | - Kanako Minami
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, Higashiosaka, Osaka, Japan
| | - Nanami Ueda
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, Higashiosaka, Osaka, Japan
| | - Toshifumi Tsujiuchi
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, Higashiosaka, Osaka, Japan
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Minami K, Ueda N, Ishimoto K, Tsujiuchi T. Lysophosphatidic acid receptor-2 (LPA 2)-mediated signaling enhances chemoresistance in melanoma cells treated with anticancer drugs. Mol Cell Biochem 2020; 469:89-95. [PMID: 32301060 DOI: 10.1007/s11010-020-03730-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 04/07/2020] [Indexed: 10/24/2022]
Abstract
Lysophosphatidic acid (LPA) signaling through LPA receptors (LPA1 to LPA6) regulates a variety of malignant properties in cancer cells. Recently, we show that LPA2 expression is elevated by long-term cisplatin (CDDP) treatment in melanoma A375 cells. In the present study, we investigated whether LPA2-mediated signaling is involved in the modulation of chemoresistance in A375 cells. In cell survival assay, cells were treated with CDDP and dacarbazine (DTIC) every 24 h for 2 days. The cell survival rates to CDDP and DTIC were markedly increased by an LPA2 agonist, GRI-977143. To validate the effects of LPA2 on cell survival, LPA2 knockdown cells were generated from A375 cells. The cell survival rates elevated by GRI-977143 were suppressed by LPA2 knockdown. To evaluate the roles of LPA2-mediated signaling in cell survival, cells were pretreated with a Gi protein inhibitor, pertussis toxin (PTX). In the presence of GRI-977143, the cell survival rates to CDDP and DTIC were significantly lower in PTX-treated cells than in untreated cells. In addition, pretreatment of an adenylyl cyclase inhibitor, SQ22536, increased the cell survival of A375 cells treated with CDDP and DTIC. These results suggest that LPA2-mediated signaling plays an important role in the enhancement of chemoresistance of A375 cells treated with anticancer drugs.
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Affiliation(s)
- Kanako Minami
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka, 577-8502, Japan
| | - Nanami Ueda
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka, 577-8502, Japan
| | - Kaichi Ishimoto
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka, 577-8502, Japan
| | - Toshifumi Tsujiuchi
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka, 577-8502, Japan.
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Ueda N, Minami K, Ishimoto K, Tsujiuchi T. Effects of lysophosphatidic acid (LPA) receptor-2 (LPA 2) and LPA 3 on the regulation of chemoresistance to anticancer drug in lung cancer cells. Cell Signal 2020; 69:109551. [PMID: 32006610 DOI: 10.1016/j.cellsig.2020.109551] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 12/17/2022]
Abstract
Lysophosphatidic acid (LPA) mediates a variety of biological functions via the binding of G protein-coupled LPA receptors (LPA receptor-1 (LPA1) to LPA6). This study aimed to investigate the roles of LPA2 and LPA3 in the modulation of chemoresistance to anticancer drug in lung cancer A549 cells. In cell survival assay, cells were treated with cisplatin (CDDP) every 24 h for 2 days. The cell survival rate to CDDP of A549 cells was significantly elevated by an LPA2 agonist, GRI-977143. To evaluate the roles of LPA2-mediated signaling in cell survival during tumor progression, highly migratory (A549-R10) cells were generated from A549 cells. In the presence of GRI-977143, the cell survival rate to CDDP of A549-R10 cells were markedly higher than that of A549 cells, correlating with LPAR2 expression level. Moreover, to assess the effects of long-term anticancer drug treatment on cell survival, the long-term CDDP treated (A549-CDDP) cells were established from A549 cells. The cell survival rate to CDDP of A549-CDDP cells was elevated by GRI-977143. Since LPAR3 expression level was significantly higher in A549-CDDP cells than in A549 cells, we investigated the roles of LPA3 in the cell survival to CDDP of A549 cells, using an LPA3 agonist, 1-oleoyl-2-methyl-sn-glycero-3-phosphothionate ((2S)-OMPT). The cell survival rate to CDDP of A549 cells was significantly reduced by (2S)-OMPT treatment. In the presence of (2S)-OMPT, the cell survival rate to CDDP of A549 cells was elevated by LPA3 knockdown. These results suggest that LPA signaling via LPA2 and LPA3 is involved in the regulation of chemoresistance in A549 cells treated with CDDP.
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Affiliation(s)
- Nanami Ueda
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Kanako Minami
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Kaichi Ishimoto
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Toshifumi Tsujiuchi
- Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502, Japan.
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Rieg AD, Suleiman S, Anker C, Verjans E, Rossaint R, Uhlig S, Martin C. PDGF-BB regulates the pulmonary vascular tone: impact of prostaglandins, calcium, MAPK- and PI3K/AKT/mTOR signalling and actin polymerisation in pulmonary veins of guinea pigs. Respir Res 2018; 19:120. [PMID: 29921306 PMCID: PMC6009037 DOI: 10.1186/s12931-018-0829-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 06/13/2018] [Indexed: 12/15/2022] Open
Abstract
Background Platelet-derived growth factor (PDGF)-BB and its receptor PDGFR are highly expressed in pulmonary hypertension (PH) and mediate proliferation. Recently, we showed that PDGF-BB contracts pulmonary veins (PVs) and that this contraction is prevented by inhibition of PDGFR-β (imatinib/SU6668). Here, we studied PDGF-BB-induced contraction and downstream-signalling in isolated perfused lungs (IPL) and precision-cut lung slices (PCLS) of guinea pigs (GPs). Methods In IPLs, PDGF-BB was perfused after or without pre-treatment with imatinib (perfused/nebulised), the effects on the pulmonary arterial pressure (PPA), the left atrial pressure (PLA) and the capillary pressure (Pcap) were studied and the precapillary (Rpre) and postcapillary resistance (Rpost) were calculated. Perfusate samples were analysed (ELISA) to detect the PDGF-BB-induced release of prostaglandin metabolites (TXA2/PGI2). In PCLS, the contractile effect of PDGF-BB was evaluated in pulmonary arteries (PAs) and PVs. In PVs, PDGF-BB-induced contraction was studied after inhibition of PDGFR-α/β, L-Type Ca2+-channels, ROCK/PKC, prostaglandin receptors, MAP2K, p38-MAPK, PI3K-α/γ, AKT/PKB, actin polymerisation, adenyl cyclase and NO. Changes of the vascular tone were measured by videomicroscopy. In PVs, intracellular cAMP was measured by ELISA. Results In IPLs, PDGF-BB increased PPA, Pcap and Rpost. In contrast, PDGF-BB had no effect if lungs were pre-treated with imatinib (perfused/nebulised). In PCLS, PDGF-BB significantly contracted PVs/PAs which was blocked by the PDGFR-β antagonist SU6668. In PVs, inhibition of actin polymerisation and inhibition of L-Type Ca2+-channels reduced PDGF-BB-induced contraction, whereas inhibition of ROCK/PKC had no effect. Blocking of EP1/3- and TP-receptors or inhibition of MAP2K-, p38-MAPK-, PI3K-α/γ- and AKT/PKB-signalling prevented PDGF-BB-induced contraction, whereas inhibition of EP4 only slightly reduced it. Accordingly, PDGF-BB increased TXA2 in the perfusate, whereas PGI2 was increased in all groups after 120 min and inhibition of IP-receptors did not enhance PDGF-BB-induced contraction. Moreover, PDGF-BB increased cAMP in PVs and inhibition of adenyl cyclase enhanced PDGF-BB-induced contraction, whereas inhibition of NO-formation only slightly increased it. Conclusions PDGF-BB/PDGFR regulates the pulmonary vascular tone by the generation of prostaglandins, the increase of calcium, the activation of MAPK- or PI3K/AKT/mTOR signalling and actin remodelling. More insights in PDGF-BB downstream-signalling may contribute to develop new therapeutics for PH.
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Affiliation(s)
- Annette D Rieg
- Department of Anaesthesiology, Medical Faculty RWTH-Aachen, Aachen, Germany.
| | - Said Suleiman
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Carolin Anker
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Eva Verjans
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Rolf Rossaint
- Department of Anaesthesiology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Stefan Uhlig
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Christian Martin
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
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Maihöfer NA, Suleiman S, Dreymüller D, Manley PW, Rossaint R, Uhlig S, Martin C, Rieg AD. Imatinib relaxes the pulmonary venous bed of guinea pigs. Respir Res 2017; 18:32. [PMID: 28178968 PMCID: PMC5299687 DOI: 10.1186/s12931-017-0514-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/19/2017] [Indexed: 12/15/2022] Open
Abstract
Background Recently, the IMPRES study revealed that systemic imatinib improves exercise capacity in patients with advanced pulmonary arterial hypertension. Imatinib blocks the tyrosine kinase activity of the platelet-derived growth factor (PDGF)-receptor (PDGFR), acts antiproliferative and relaxes pulmonary arteries. However so far, the relaxant effects of imatinib on pulmonary veins (PVs) and on the postcapillary resistance are unknown, although pulmonary hypertension (PH) due to left heart disease (LHD) is most common and primarily affects PVs. Next, it is unknown whether activation of PDGFR alters the pulmonary venous tone. Due to the reported adverse effects of systemic imatinib, we evaluated the effects of nebulized imatinib on the postcapillary resistance. Methods Precision-cut lung slices (PCLS) were prepared from guinea pigs. PVs were pre-constricted with Endothelin-1 (ET-1) and the imatinib-induced relaxation was studied by videomicroscopy; PDGF-BB-related vascular properties were evaluated as well. The effects of perfused/nebulized imatinib on the postcapillary resistance were studied in cavine isolated perfused lungs (IPL). Intracellular cAMP/cGMP was measured by ELISA in PVs. Results In PCLS, imatinib (100 μM) relaxed pre-constricted PVs (126%). In PVs, imatinib increased cAMP, but not cGMP and inhibition of adenyl cyclase or protein kinase A reduced the imatinib-induced relaxation. Further, inhibition of KATP-channels, \documentclass[12pt]{minimal}
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\begin{document}$$ {\mathrm{BK}}_{\mathrm{Ca}}^{2+} $$\end{document}BKCa2+-channels or Kv-channels diminished the imatinib-induced relaxation, whereas inhibition of NO-signaling was without effect. In the IPL, perfusion or nebulization of imatinib reduced the ET-1-induced increase of the postcapillary resistance. In PCLS, PDGF-BB contracted PVs, which was blocked by imatinib and by the PDGFR-β kinase inhibitor SU6668, whereas inhibition of PDGFR-α (ponatinib) had no significant effect. Conversely, PDGFR-β kinase inhibitors (SU6668/DMPQ) relaxed PVs pre-constricted with ET-1 comparable to imatinib, whereas the PDGFR-α kinase inhibitor ponatinib did not. Conclusions Imatinib-induced relaxation depends on cAMP and on the activation of K+-channels. Perfused or nebulized imatinib significantly reduces the postcapillary resistance in the pre-constricted (ET-1) pulmonary venous bed. Hence, nebulization of imatinib is feasible and might reduce systemic side effects. Conversely, PDGF-BB contracts PVs by activation of PDGFR-β suggesting that imatinib-induced relaxation depends on PDGFR-β-antagonism. Imatinib combines short-term relaxant and long-term antiproliferative effects. Thus, imatinib might be a promising therapy for PH due to LHD.
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Affiliation(s)
- Nina A Maihöfer
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, RWTH-Aachen, Aachen, Germany
| | - Said Suleiman
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, RWTH-Aachen, Aachen, Germany
| | - Daniela Dreymüller
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, RWTH-Aachen, Aachen, Germany
| | | | - Rolf Rossaint
- Department of Anesthesiology, Medical Faculty Aachen, RWTH-Aachen, Aachen, Germany
| | - Stefan Uhlig
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, RWTH-Aachen, Aachen, Germany
| | - Christian Martin
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, RWTH-Aachen, Aachen, Germany
| | - Annette D Rieg
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, RWTH-Aachen, Aachen, Germany. .,Department of Anesthesiology, Medical Faculty Aachen, RWTH-Aachen, Aachen, Germany.
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Rieg AD, Suleiman S, Perez-Bouza A, Braunschweig T, Spillner JW, Schröder T, Verjans E, Schälte G, Rossaint R, Uhlig S, Martin C. Milrinone relaxes pulmonary veins in guinea pigs and humans. PLoS One 2014; 9:e87685. [PMID: 24498166 PMCID: PMC3909212 DOI: 10.1371/journal.pone.0087685] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 01/01/2014] [Indexed: 12/14/2022] Open
Abstract
Introduction The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH). However, its action on pulmonary veins (PVs) is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs) and humans. Material and Methods Precision-cut lung slices (PCLS) were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL). Results In the IPL (GP), milrinone (10 µM) lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP), milrinone relaxed naïve and pre-constricted PVs (120%) and this relaxation was attenuated by inhibition of protein kinase G (KT 5823), adenyl cyclase (SQ 22536) and protein kinase A (KT 5720), but not by inhibition of NO-synthesis (L-NAME). In addition, milrinone-induced relaxation was dependent on the activation of KATP-, BKCa2+- and Kv-channels. Human PVs also relaxed to milrinone (121%), however only if pre-constricted. Discussion Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on KATP-, BKCa2+- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.
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Affiliation(s)
- Annette D. Rieg
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
- Department of Anesthesiology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
- * E-mail:
| | - Said Suleiman
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Alberto Perez-Bouza
- Institute of Pathology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
- Institute of Pathology, Medical Faculty of Rhenish Friedrich-Wilhelms University Bonn, Bonn, Germany
| | - Till Braunschweig
- Institute of Pathology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Jan W. Spillner
- Department of Cardiac and Thorax Surgery, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Thomas Schröder
- Department of Surgery, Luisenhospital Aachen, Aachen, Germany
| | - Eva Verjans
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
- Department of Pediatrics, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Gereon Schälte
- Department of Anesthesiology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Rolf Rossaint
- Department of Anesthesiology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Stefan Uhlig
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Christian Martin
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
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Rieg AD, Rossaint R, Verjans E, Maihöfer NA, Uhlig S, Martin C. Levosimendan Relaxes Pulmonary Arteries and Veins in Precision-Cut Lung Slices - The Role of KATP-Channels, cAMP and cGMP. PLoS One 2013; 8:e66195. [PMID: 23824760 PMCID: PMC3688856 DOI: 10.1371/journal.pone.0066195] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 05/05/2013] [Indexed: 12/22/2022] Open
Abstract
INTRODUCTION Levosimendan is approved for left heart failure and is also used in right heart failure to reduce right ventricular afterload. Despite the fact that pulmonary arteries (PAs) and pulmonary veins (PVs) contribute to cardiac load, their responses to levosimendan are largely unknown. MATERIALS AND METHODS Levosimendan-induced vasorelaxation of PAs and PVs was studied in precision-cut lung slices from guinea pigs by videomicroscopy; baseline luminal area was defined as 100%. Intracellular cAMP- and cGMP-levels were measured by ELISA and NO end products were determined by the Griess reaction. RESULTS Levosimendan relaxed control PVs (116%) and those pre-constricted with an endothelinA-receptor agonist (119%). PAs were only relaxed if pre-constricted (115%). Inhibition of KATP-channels (glibenclamide), adenyl cyclase (SQ 22536) and protein kinase G (KT 5823) largely attenuated the levosimendan-induced relaxation in control PVs, as well as in pre-constricted PAs and PVs. Inhibition of BKCa (2+)-channels (iberiotoxin) and Kv-channels (4-aminopyridine) only contributed to the relaxant effect of levosimendan in pre-constricted PAs. In both PAs and PVs, levosimendan increased intracellular cAMP- and cGMP-levels, whereas NO end products remained unchanged. Notably, basal NO-levels were higher in PVs. The KATP-channel activator levcromakalim relaxed PAs dependent on cAMP/PKA/PKG and increased cAMP-levels in PAs. DISCUSSION Levosimendan initiates complex and divergent signaling pathways in PAs and PVs. Levosimendan relaxes PAs and PVs primarily via KATP-channels and cAMP/cGMP; in PAs, BKCa (2+)- and Kv-channels are also involved. Our findings with levcromakalim do further suggest that in PAs the activation of KATP-channels leads to the production of cAMP/PKA/PKG. In conclusion, these results suggest that levosimendan might reduce right ventricular afterload by relaxation of PAs as well as pulmonary hydrostatic pressure and pulmonary edema by relaxation of PVs.
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Affiliation(s)
- Annette D. Rieg
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, Rhenish Westphalian Technical University, Aachen, Germany
- Department of Anesthesiology, Medical Faculty Aachen, Rhenish Westphalian Technical University, Aachen, Germany
- * E-mail:
| | - Rolf Rossaint
- Department of Anesthesiology, Medical Faculty Aachen, Rhenish Westphalian Technical University, Aachen, Germany
| | - Eva Verjans
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, Rhenish Westphalian Technical University, Aachen, Germany
- Department of Pediatrics, Medical Faculty Aachen, Rhenish Westphalian Technical University, Aachen, Germany
| | - Nina A. Maihöfer
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, Rhenish Westphalian Technical University, Aachen, Germany
| | - Stefan Uhlig
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, Rhenish Westphalian Technical University, Aachen, Germany
| | - Christian Martin
- Institute of Pharmacology and Toxicology, Medical Faculty Aachen, Rhenish Westphalian Technical University, Aachen, Germany
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Brunskole Hummel I, Reinartz MT, Kälble S, Burhenne H, Schwede F, Buschauer A, Seifert R. Dissociations in the effects of β2-adrenergic receptor agonists on cAMP formation and superoxide production in human neutrophils: support for the concept of functional selectivity. PLoS One 2013; 8:e64556. [PMID: 23741338 PMCID: PMC3669315 DOI: 10.1371/journal.pone.0064556] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 04/15/2013] [Indexed: 12/02/2022] Open
Abstract
In neutrophils, activation of the β2-adrenergic receptor (β2AR), a Gs-coupled receptor, inhibits inflammatory responses, which could be therapeutically exploited. The aim of this study was to evaluate the effects of various β2AR ligands on adenosine-3',5'-cyclic monophosphate (cAMP) accumulation and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-induced superoxide anion (O2(•-)) production in human neutrophils and to probe the concept of ligand-specific receptor conformations (also referred to as functional selectivity or biased signaling) in a native cell system. This is an important question because so far, evidence for functional selectivity has been predominantly obtained with recombinant systems, due to the inherent difficulties to genetically manipulate human native cells. cAMP concentration was determined by HPLC/tandem mass spectrometry, and O2(•-) formation was assessed by superoxide dismutase-inhibitable reduction of ferricytochrome c. β2AR agonists were generally more potent in inhibiting fMLP-induced O2(•-) production than in stimulating cAMP accumulation. (-)-Ephedrine and dichloroisoproterenol were devoid of any agonistic activity in the cAMP assay, but partially inhibited fMLP-induced O2(•-) production. Moreover, (-)-adrenaline was equi-efficacious in both assays whereas the efficacy of salbutamol was more than two-fold higher in the O2(•-) assay. Functional selectivity was visualized by deviations of ligand potencies and efficacies from linear correlations for various parameters. We obtained no evidence for involvement of protein kinase A in the inhibition of fMLP-induced O2(•-) production after β2AR-stimulation although cAMP-increasing substances inhibited O2(•-) production. Taken together, our data corroborate the concept of ligand-specific receptor conformations with unique signaling capabilities in native human cells and suggest that the β2AR inhibits O2(•-) production in a cAMP-independent manner.
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Affiliation(s)
- Irena Brunskole Hummel
- Institute of Pharmacology, Medical School of Hannover, Hannover, Germany
- Department of Pharmaceutical and Medicinal Chemistry II, University of Regensburg, Regensburg, Germany
| | | | - Solveig Kälble
- Institute of Pharmacology, Medical School of Hannover, Hannover, Germany
| | - Heike Burhenne
- Institute of Pharmacology, Medical School of Hannover, Hannover, Germany
| | | | - Armin Buschauer
- Department of Pharmaceutical and Medicinal Chemistry II, University of Regensburg, Regensburg, Germany
| | - Roland Seifert
- Institute of Pharmacology, Medical School of Hannover, Hannover, Germany
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12
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Leeya Y, Mulvany MJ, Queiroz EF, Marston A, Hostettmann K, Jansakul C. Hypotensive activity of an n-butanol extract and their purified compounds from leaves of Phyllanthus acidus (L.) Skeels in rats. Eur J Pharmacol 2010; 649:301-13. [PMID: 20868659 DOI: 10.1016/j.ejphar.2010.09.038] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 07/26/2010] [Accepted: 09/14/2010] [Indexed: 10/19/2022]
Abstract
We aimed to investigate the effects, identify the active substances and establish the mechanisms involved in the hypotensive activity of an n-butanol extract from leaves of Phyllanthus acidus (PA extract). PA extract caused a decrease in blood pressure of anesthetized rats that was not modified by atropine or propranolol. PA extract caused a persistent dilatation of thoracic aortic rings preconstricted with either phenylephrine or KCl, and these effects were not modified by LNA or removal of the vascular endothelium. For phenylephrine-preconstricted aortic rings, the dilatory activity of the PA extract was not modified by atropine, propranolol or indomethacin. TEA, glybenclamide or ODQ significantly inhibited the dilatory activity of the PA extract on endothelium-denuded aortic rings. Nifedipine or a Ca(2+)-free medium depressed the aortic rings constrictor response to phenylephrine, and that was further augmented by the PA extract. Adenosine, 4-hydroxybenzoic acid, caffeic acid, hypogallic acid, and kaempferol were isolated from the PA extract. Each caused a decrease in blood pressure and dilatation of the aortic rings. LNA or removal of the endothelium reduced this activity. ODQ and TEA attenuated the vasodilatory activity of adenosine whereas glybenclamide and ODQ attenuated the effect of hypogallic acid. These results suggest that the hypotensive activities of the PA extract is likely the result of the direct action of these five compounds on the blood vessels by stimulating release of nitric oxide from the vascular endothelium, in part through stimulation of soluble guanylate cyclase, and opening of K(ATP) and K(Ca) channels in the vascular smooth muscle.
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Affiliation(s)
- Yuttapong Leeya
- Department of Physiology, Faculty of Science, Prince of Songkla University, Hat-Yai, 90112, Thailand
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13
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Functional and molecular characterization of prostaglandin E2 dilatory receptors in the rat craniovascular system in relevance to migraine. Cephalalgia 2010; 30:1110-22. [DOI: 10.1177/0333102409357957] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Introduction: Migraine pain is thought to involve an increase in trigeminal nerve terminal activity around large cerebral and meningeal arteries, leading to vasodilatation. Because prostaglandin E2 (PGE2) is elevated in cephalic venous blood during migraine attacks, and is also capable of inducing headache in healthy volunteers, we hypothesize that PGE2 dilatory receptors, EP2 and EP4, mediate the response. Materials and methods: By the use of specific agonists and antagonists, the dilatory effect of PGE2 was characterized in rat cranial arteries by use of in vivo and in vitro methods. Furthermore, EP2 and EP4 quantitative messenger RNA (mRNA) receptor expression was studied in the rat craniovascular system. Results: Our results suggest that EP4, and to a lesser degree EP2, receptors mediate the dilatory effect of PGE2 in the craniovascular system in rats. Thus, antagonism of these receptors might be of therapeutic relevance in migraine.
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Kellogg R, Mackie K, Straiker A. Cannabinoid CB1 receptor-dependent long-term depression in autaptic excitatory neurons. J Neurophysiol 2009; 102:1160-71. [PMID: 19494194 DOI: 10.1152/jn.00266.2009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Long-term depression (LTD) of synaptic signaling-lasting from tens of minutes to hours or longer-is a widespread form of synaptic plasticity in the brain. Neurons express diverse forms of LTD, including autaptic LTD (autLTD) observed in cultured hippocampal neurons, the mechanism of which remains unknown. We have recently reported that autaptic neurons express both endocannabinoid-mediated depolarization-induced suppression of excitation (DSE) and metabotropic suppression of excitation (MSE). We now report that activating cannabinoid CB(1) receptors is necessary for the induction of autLTD. Most surprisingly, CB(1) does not induce autLTD via the G(i/o) proteins typically activated by this receptor nor with G(s). Rather, the requirements of presynaptic phospholipase C and filled calcium stores suggest G(q). In autLTD, a 3- to 4-min activation of the receptor by the endocannabinoid 2-arachidonoyl glycerol leads to prolonged inhibition while leaving short-term inhibition (e.g., DSE) intact. autLTD requires activation of both metabo- and ionotropic glutamate receptors. autLTD also requires MEK/ERK activation. Under certain conditions, one or more DSE stimuli will elicit autLTD. It is becoming evident that cannabinoids mediate multiple forms of plasticity at a single synapse, stretching temporally from tens of seconds (DSE/MSE) to tens of minutes (autLTD) to hours (CB(1) desensitization). Our findings imply a remarkable flexibility for the cannabinoid signaling system whereby discrete mechanisms of CB(1) activation within a single neuron yield temporally and mechanistically distinct forms of plasticity.
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Affiliation(s)
- Ryan Kellogg
- Department of Anesthesiology, University of Washington, Seattle, Washington, USA
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15
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Ye Y, Wei J, Dai X, Gao Q. Computational studies of the binding modes of A 2A adenosine receptor antagonists. Amino Acids 2008; 35:389-96. [PMID: 17978889 PMCID: PMC7087644 DOI: 10.1007/s00726-007-0604-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 09/12/2007] [Indexed: 11/25/2022]
Abstract
A molecular docking study was performed on several structurally diverse A(2A) AR antagonists, including xanthines, and non-xanthine type antagonists to investigate their binding modes with A(2A) adenosine receptor (AR), one of the four subtypes of AR, which is currently of great interest as a target for therapeutic intervention, in particular for Parkinson's disease. The high-affinity binding site was found to be a hydrophobic pocket with the involvement of hydrogen bonding interactions as well as pi-pi stacking interactions with the ligands. The detailed binding modes for both xanthine and non-xanthine type A(2A) antagonists were compared and the essential features were extracted and converted to database searchable queries for virtual screening study of novel A(2A) AR antagonists. Findings from this study are helpful for elucidating the binding pattern of A(2A) AR antagonists and for the design of novel active ligands.
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Affiliation(s)
- Y. Ye
- />School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - J. Wei
- />School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - X. Dai
- />Chemistry Department, XenoPort Inc., Santa Clara, CA U.S.A
| | - Q. Gao
- />Chemistry Department, XenoPort Inc., Santa Clara, CA U.S.A
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16
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Wei J, Wang S, Gao S, Dai X, Gao Q. 3D-Pharmacophore Models for Selective A2A and A2B Adenosine Receptor Antagonists. J Chem Inf Model 2007; 47:613-25. [PMID: 17330954 DOI: 10.1021/ci600410m] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Three-dimensional pharmacophore models were generated for A2A and A2B adenosine receptors (ARs) based on highly selective A2A and A2B antagonists using the Catalyst program. The best pharmacophore model for selective A2A antagonists (Hypo-A2A) was obtained through a careful validation process. Four features contained in Hypo-A2A (one ring aromatic feature (R), one positively ionizable feature (P), one hydrogen bond acceptor lipid feature (L), and one hydrophobic feature (H)) seem to be essential for antagonists in terms of binding activity and A2A AR selectivity. The best pharmacophore model for selective A2B antagonists (Hypo-A2B) was elaborated by modifying the Catalyst common features (HipHop) hypotheses generated from the selective A2B antagonists training set. Hypo-A2B also consists of four features: one ring aromatic feature (R), one hydrophobic aliphatic feature (Z), and two hydrogen bond acceptor lipid features (L). All features play an important role in A2B AR binding affinity and are essential for A2B selectivity. Both A2A and A2B pharmacophore models have been validated toward a wide set of test molecules containing structurally diverse selective antagonists of all AR subtypes. They are capable of identifying correspondingly high potent antagonists and differentiating antagonists between subtypes. The results of our study will act as a valuable tool for retrieving structurally diverse compounds with desired biological activities and designing novel selective adenosine receptor ligands.
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Affiliation(s)
- Jing Wei
- School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, P.R. China
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17
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Abebe W, Maddux WF. Roles of nitric oxide and prostacyclin in triethyleneglycol dimethacrylate (TEGDMA)-induced vasorelaxation. Dent Mater 2006; 22:37-44. [PMID: 16040116 DOI: 10.1016/j.dental.2005.02.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Revised: 12/15/2004] [Accepted: 02/08/2005] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Most dental resinous materials contain the diluent monomer triethyleneglycol dimethacrylate (TEGDMA), which has been reported to be bioactive. Previously, it was demonstrated that TEGDMA induces vasorelaxation. The present study examines the mechanism(s) of the TEGDMA-induced vasorelaxation by measuring vascular nitrite and prostacyclin levels. METHODS Nitrite and prostacyclin levels were assayed in rat aortic tissues in response to TEGDMA. The involvement of guanylyl and adenylyl cyclases in TEGDMA-induced aortic vasorelaxation was determined using the enzyme inhibitors 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (SQ22536), respectively. RESULTS TEGDMA enhanced the levels of nitrites in endothelium-intact and that of protacyclin in both endothelium-intact and denuded rat aortas. The increase in nitrites was associated with endothelium-dependent aortic relaxation mediated via the activation of guanylyl cyclase, while the increase in prostacyclin was associated with both endothelium-dependent and independent relaxation linked to adenylyl cyclase stimulation. SIGNIFICANCE Data from the present investigation can be relevant to dental practice employing materials containing TEGDMA by providing insights into the vasorelaxant effect of the monomer following placement of the materials in the oral cavity. Additional studies that are more relevant to the clinical situation are required to confirm these initial results and further explore their implications.
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Affiliation(s)
- Worku Abebe
- Department of Oral Biology and Maxillofacial Pathology, School of Dentistry, CL-2130, Medical College of Georgia, Augusta, GA 30912-1128, USA.
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Mallem MY, Toumaniantz G, Serpillon S, Gautier F, Gogny M, Desfontis JC, Gauthier C. Impairment of the low-affinity state beta1-adrenoceptor-induced relaxation in spontaneously hypertensive rats. Br J Pharmacol 2004; 143:599-605. [PMID: 15466443 PMCID: PMC1575435 DOI: 10.1038/sj.bjp.0705990] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1 In hypertension, a decrease of the vascular beta-adrenergic relaxation has been described. However, the specific involvement of each beta-adrenoceptor (beta-AR) subtype, in particular the low-affinity state of beta1-AR, has not yet been evaluated. We investigated whether the low-affinity state of beta1-AR-induced relaxation was impaired in Spontaneously Hypertensive Rats (SHR). 2 The relaxant responses to CGP 12177 and cyanopindolol, low-affinity state beta1-AR agonists (with beta1-/beta2-AR antagonistic and partial beta3-AR agonistic properties) were evaluated on thoracic aortic rings isolated from 12-weeks-old Wistar Kyoto rats (WKY) and SHR. 3 In WKY, CGP 12177 and cyanopindolol produced an endothelium and nitric oxide (NO)-independent relaxation. CGP 12177-induced endothelium-independent relaxation was not modified either by beta1-, beta2-AR (nadolol) or beta3-AR (L-748337 or SR 59230A) antagonists but was significantly reduced by high concentrations of CGP 20712A (P<0.05). This relaxation was also reduced by adenylyl cyclase inhibitors, SQ 22536 or MDL 12330A. 4 In SHR, CGP 12177 produced mainly an endothelium and NO-dependent relaxation. This effect was not modified by nadolol, but was strongly reduced by beta3-AR blockade. Endothelium-independent relaxation to CGP 12177 was not altered by adenylyl cyclase inhibition, but was amplified in preparations from pertussis toxin-pretreated SHR. 5 The immunohistochemical analysis revealed an upregulation of beta3-AR in the endothelial layer of SHR aorta, whereas the beta3-AR-induced relaxation was not modified. 6 In conclusion, we demonstrated an impaired low-affinity state of the beta1-AR-induced relaxation and an upregulation of the beta3-AR in hypertension. Some clinical implications of those findings are discussed.
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MESH Headings
- Adrenergic beta-Antagonists/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Dose-Response Relationship, Drug
- Enzyme Inhibitors/pharmacology
- Hypertension/physiopathology
- Immunohistochemistry
- In Vitro Techniques
- Male
- Muscle Relaxation/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiopathology
- Nitric Oxide Synthase/antagonists & inhibitors
- Nitric Oxide Synthase Type III
- Pindolol/analogs & derivatives
- Pindolol/pharmacology
- Propanolamines/pharmacology
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Receptors, Adrenergic, beta-1/drug effects
- omega-N-Methylarginine/pharmacology
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Affiliation(s)
- Mohamed Yassine Mallem
- UPSP 5304 de Physiopathologie Animale et de Pharmacologie Fonctionnelle, Ecole Nationale Vétérinaire, Nantes, France
| | | | - Sabrina Serpillon
- UPSP 5304 de Physiopathologie Animale et de Pharmacologie Fonctionnelle, Ecole Nationale Vétérinaire, Nantes, France
- Institut du Thorax, Inserm U533, Nantes, France
| | - Freddy Gautier
- UPSP 5304 de Physiopathologie Animale et de Pharmacologie Fonctionnelle, Ecole Nationale Vétérinaire, Nantes, France
| | - Marc Gogny
- UPSP 5304 de Physiopathologie Animale et de Pharmacologie Fonctionnelle, Ecole Nationale Vétérinaire, Nantes, France
| | - Jean-Claude Desfontis
- UPSP 5304 de Physiopathologie Animale et de Pharmacologie Fonctionnelle, Ecole Nationale Vétérinaire, Nantes, France
- Author for correspondence:
| | - Chantal Gauthier
- Institut du Thorax, Inserm U533, Nantes, France
- Faculté des Sciences et Techniques, Nantes, France
- Author for correspondence:
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Abebe W, Mozaffari MS. Effect of taurine deficiency on adenosine receptor-mediated relaxation of the rat aorta. Vascul Pharmacol 2003; 40:219-28. [PMID: 14746829 DOI: 10.1016/j.vph.2003.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We recently demonstrated that chronic taurine supplementation or deficiency causes alterations in reactivity of the rat aorta to several vasoactive agents. In the present investigation, we examined the effects beta-alanine-induced endogenous taurine deficiency on the mechanical responsiveness of the isolated rat aorta to adenosine receptor stimulation with 2-chloroadenosine (CAD), 5'-N-ethylcarboxyamidoadenosine (NECA), and N(6)-cyclopentyladenosine (CPA). The adenosine analogs produced concentration-dependent (1 x 10(-9)-3 x 10(-3) M) relaxations of aortas from both control and beta-alanine-treated rats with the rank order of potencies NECA>CAD>CPA, which was consistent with A(2) receptor identification. CAD and NECA induced both endothelium-dependent and -independent relaxations of the aortas. The endothelium-dependent responses to both agents and the independent responses to CAD were significantly attenuated by beta-alanine treatment. The relaxation responses of the aortas from control and taurine-deficient rats to CAD and NECA were markedly antagonized by ZM241385 (10(-5) M), suggesting the involvement of A(2A) adenosine receptors. Further, N-nitro-L-arginine methyl ester (L-NAME; 10(-5) M) significantly attenuated the endothelium-mediated relaxation produced by CAD and NECA in both groups. However, the inhibitory effect of L-NAME was less on the beta-alanine-treated tissues, providing evidence that the effect of taurine deficiency was linked to a reduction in nitric oxide generation. As in the aorta, CAD produced both endothelium-dependent and -independent relaxation responses in the rat superior mesenteric artery, and both responses were inhibited by chronic beta-alanine treatment, suggesting that not only similar responses can be generated by a given adenosine agonist in different vascular beds, but also beta-alanine treatment modulates these responses. On the other hand, while CPA elicited only endothelium-independent aortic relaxation, this response was not altered by taurine deficiency. The results indicate that endogenous taurine deficiency causes differential inhibitory effects on adenosine receptor-mediated vasorelaxation, depending upon the agonists used. Given the recognized role of adenosine in the vasculature, these alterations suggest taurine-mediated modulation of blood flow regulation.
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Affiliation(s)
- Worku Abebe
- Department of Oral Biology and Maxillofacial Pathology, School of Dentistry, CB 3710, Medical College of Georgia, Augusta, GA 30912-1128, USA.
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20
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Grbović L, Radenković M. Analysis of adenosine vascular effect in isolated rat aorta: possible role of Na+/K+-ATPase. PHARMACOLOGY & TOXICOLOGY 2003; 92:265-71. [PMID: 12787258 DOI: 10.1034/j.1600-0773.2003.920603.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The present experiments were undertaken in order to examine the effect of adenosine in isolated rat aorta, to investigate the possible role of intact endothelium and endothelial relaxing factors in this action and to determine which population of adenosine receptors is involved in rat aorta response to adenosine. Adenosine (0.1-300 microM) produced concentration-dependent (intact rings: pD2=4.39+/-0.09) and endothelium-independent (denuded rings: pD2=4.52+/-0.12) relaxation of isolated rat aorta. In the presence of high concentration of K+ (100 mM) adenosine-evoked relaxation was significantly reduced (maximal relaxation in denuded rings: control - 92.1+/-9.8 versus K+- 54.4+/-5.0). Similar results were obtained after incubation of ouabain (100 microM) or glibenclamide (1 microM). In K+-free solution, K+ (1-10 mM)-induced rat aorta relaxant response was significantly inhibited by ouabain (100 microM). Application of indomethacin (10 microM), NG-nitro-L-arginine (10 microM) or tetraethylammonium (500 microM) did not alter the adenosine-elicited effect in rat aorta. 8-(3-Chlorostyril)-caffeine (0.3-3 microM), a selective A2A-receptor antagonist, significantly reduced adenosine-induced relaxation of rat aorta in a concentration-dependent manner (pKB=6.57). Conversely, 1,3-dipropyl-8-cyclopentylxanthine (10 nM), an A1-receptor antagonist, did not affect adenosine-evoked dilatation. These results indicate that in isolated rat aorta, adenosine produces endothelium-independent relaxation, which is most probably dependent upon activation of smooth muscle Na+/K+-ATPase, and opening of ATP-sensitive K+ channels, to a smaller extent. According to receptor analysis, vasorelaxant action of adenosine in rat aorta is partly induced by activation of smooth muscle adenosine A2A receptors.
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MESH Headings
- Adenosine/pharmacology
- Adenosine/physiology
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- In Vitro Techniques
- Male
- Muscle Relaxation/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Purinergic P1 Receptor Agonists
- Purinergic P1 Receptor Antagonists
- Rats
- Rats, Wistar
- Receptor, Adenosine A2A
- Receptors, Purinergic P1/physiology
- Sodium-Potassium-Exchanging ATPase/metabolism
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Leposava Grbović
- Department of Clinical Pharmacology, Pharmacology and Toxicology, Medical Faculty, University of Belgrade, P.O. Box 840, 11000 Belgrade, Yugoslavia.
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Nicholls J, Hourani SMO, Hall JM. Characterization of adenosine receptors mediating the vasodilator effects of adenosine receptor agonists in the microvasculature of the hamster cheek pouch in vivo. AUTONOMIC & AUTACOID PHARMACOLOGY 2002; 22:209-14. [PMID: 12656946 DOI: 10.1046/j.1474-8673.2002.00259.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1 The aim of this study was to characterize the adenosine receptor mediating vasodilation in the microvasculature of the hamster cheek pouch in vivo. A range of adenosine agonists was used including N6-cyclopentyladenosine (CPA) (A1 agonist), 5'-N-ethylcarboxamidoadenosine (NECA) (non-selective), 2-chloroadenosine (2CADO) (non-selective), 2-p-(2-carboxyethyl)-phenethylamino-5'-N-ethylcarboxamidoadenosine (CGS 21680) (A2A agonist), N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (IBMECA) (A3 agonist) and adenosine, as well as the adenosine antagonists 8-sulphophenyltheophylline (8-SPT) (A1/A2 antagonist), 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) (A1 antagonist) and 4-(2-[7-amino-2-(2-furyl)[1,2,4]-triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM 241385) (A2A antagonist). 2 All the adenosine analogues used induced vasodilation at concentrations between 10 nm and 1 microm, and the potency order was NECA > CGS 21680 > 2CADO > CPA=IBMECA >> adenosine, indicating an action at A2A receptors. 8-SPT (50 microm) antagonized vasodilator responses to NECA with an apparent pKB of 5.4, consistent with an action at A1 or A2 receptors and confirming that A3 receptors are not involved in this response. 3 DPCPX (10 nm) had no effect on vasodilation evoked by NECA, suggesting that this response was not mediated via A1 receptors, while ZM 241385 (10 nm) antagonized dilator responses to NECA with an apparent pKB of 8.9 consistent with an action via A2A receptors. 4 Overall these results suggest that adenosine A2A receptors mediate vasodilation in the hamster cheek pouch in vivo.
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Affiliation(s)
- J Nicholls
- School of Biomedical and Life Sciences, University of Surrey, Guildford, Surrey, UK
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Abstract
Snake envenomation employs three well integrated strategies: prey immobilization via hypotension, prey immobilization via paralysis, and prey digestion. Purines (adenosine, guanosine and inosine) evidently play a central role in the envenomation strategies of most advanced snakes. Purines constitute the perfect multifunctional toxins, participating simultaneously in all three envenomation strategies. Because they are endogenous regulatory compounds in all vertebrates, it is impossible for any prey organism to develop resistance to them. Purine generation from endogenous precursors in the prey explains the presence of many hitherto unexplained enzyme activities in snake venoms: 5'-nucleotidase, endonucleases (including ribonuclease), phosphodiesterase, ATPase, ADPase, phosphomonoesterase, and NADase. Phospholipases A(2), cytotoxins, myotoxins, and heparinase also participate in purine liberation, in addition to their better known functions. Adenosine contributes to prey immobilization by activation of neuronal adenosine A(1) receptors, suppressing acetylcholine release from motor neurons and excitatory neurotransmitters from central sites. It also exacerbates venom-induced hypotension by activating A(2) receptors in the vasculature. Adenosine and inosine both activate mast cell A(3) receptors, liberating vasoactive substances and increasing vascular permeability. Guanosine probably contributes to hypotension, by augmenting vascular endothelial cGMP levels via an unknown mechanism. Novel functions are suggested for toxins that act upon blood coagulation factors, including nitric oxide production, using the prey's carboxypeptidases. Leucine aminopeptidase may link venom hemorrhagic metalloproteases and endogenous chymotrypsin-like proteases with venom L-amino acid oxidase (LAO), accelerating the latter. The primary function of LAO is probably to promote prey hypotension by activating soluble guanylate cyclase in the presence of superoxide dismutase. LAO's apoptotic activity, too slow to be relevant to prey capture, is undoubtedly secondary and probably serves principally a digestive function. It is concluded that the principal function of L-type Ca(2+) channel antagonists and muscarinic toxins, in Dendroaspis venoms, and acetylcholinesterase in other elapid venoms, is to promote hypotension. Venom dipeptidyl peptidase IV-like enzymes probably also contribute to hypotension by destroying vasoconstrictive peptides such as Peptide YY, neuropeptide Y and substance P. Purines apparently bind to other toxins which then serve as molecular chaperones to deposit the bound purines at specific subsets of purine receptors. The assignment of pharmacological activities such as transient neurotransmitter suppression, histamine release and antinociception, to a variety of proteinaceous toxins, is probably erroneous. Such effects are probably due instead to purines bound to these toxins, and/or to free venom purines.
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Affiliation(s)
- Steven D Aird
- Laboratório de Toxinas Naturais, Universidade Estadual do Ceará, Avenida Paranjana, 1700, Itaperí, 60740-000, Fortaleza, CE, Brazil.
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