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Jiang S, Han S, Wang DW. The involvement of soluble epoxide hydrolase in the development of cardiovascular diseases through epoxyeicosatrienoic acids. Front Pharmacol 2024; 15:1358256. [PMID: 38628644 PMCID: PMC11019020 DOI: 10.3389/fphar.2024.1358256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 03/12/2024] [Indexed: 04/19/2024] Open
Abstract
Arachidonic acid (AA) has three main metabolic pathways: the cycloxygenases (COXs) pathway, the lipoxygenases (LOXs) pathway, and the cytochrome P450s (CYPs) pathway. AA produces epoxyeicosatrienoic acids (EETs) through the CYPs pathway. EETs are very unstable in vivo and can be degraded in seconds to minutes. EETs have multiple degradation pathways, but are mainly degraded in the presence of soluble epoxide hydrolase (sEH). sEH is an enzyme of bifunctional nature, and current research focuses on the activity of its C-terminal epoxide hydrolase (sEH-H), which hydrolyzes the EETs to the corresponding inactive or low activity diol. Previous studies have reported that EETs have cardiovascular protective effects, and the activity of sEH-H plays a role by degrading EETs and inhibiting their protective effects. The activity of sEH-H plays a different role in different cells, such as inhibiting endothelial cell proliferation and migration, but promoting vascular smooth muscle cell proliferation and migration. Therefore, it is of interest whether the activity of sEH-H is involved in the initiation and progression of cardiovascular diseases by affecting the function of different cells through EETs.
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Affiliation(s)
- Shan Jiang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, China
| | - Siyi Han
- Department of Anesthesiology and Pain Medicine, Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dao Wen Wang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, China
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2
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McClenaghan C, Nichols CG. Kir6.1 and SUR2B in Cantú syndrome. Am J Physiol Cell Physiol 2022; 323:C920-C935. [PMID: 35876283 PMCID: PMC9467476 DOI: 10.1152/ajpcell.00154.2022] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 12/25/2022]
Abstract
Kir6.1 and SUR2 are subunits of ATP-sensitive potassium (KATP) channels expressed in a wide range of tissues. Extensive study has implicated roles of these channel subunits in diverse physiological functions. Together they generate the predominant KATP conductance in vascular smooth muscle and are the target of vasodilatory drugs. Roles for Kir6.1/SUR2 dysfunction in disease have been suggested based on studies of animal models and human genetic discoveries. In recent years, it has become clear that gain-of-function (GoF) mutations in both genes result in Cantú syndrome (CS)-a complex, multisystem disorder. There is currently no targeted therapy for CS, but studies of mouse models of the disease reveal that pharmacological reversibility of cardiovascular and gastrointestinal pathologies can be achieved by administration of the KATP channel inhibitor, glibenclamide. Here we review the function, structure, and physiological and pathological roles of Kir6.1/SUR2B channels, with a focus on CS. Recent studies have led to much improved understanding of the underlying pathologies and the potential for treatment, but important questions remain: Can the study of genetically defined CS reveal new insights into Kir6.1/SUR2 function? Do these reveal new pathophysiological mechanisms that may be important in more common diseases? And is our pharmacological armory adequately stocked?
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Affiliation(s)
- Conor McClenaghan
- Department of Cell Biology and Physiology, Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St. Louis, Missouri
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St. Louis, Missouri
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3
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Fan F, Tian H, Geng J, Deng J, Liu Y, Chen C, Zhang S, Zhang Y, Li J, Tian H, Dart AM, Zou Y. Mechanism of Beraprost Effects on Pulmonary Hypertension: Contribution of Cross-Binding to PGE2 Receptor 4 and Modulation of O 2 Sensitive Voltage-Gated K + Channels. Front Pharmacol 2019; 9:1518. [PMID: 30713496 PMCID: PMC6346678 DOI: 10.3389/fphar.2018.01518] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/11/2018] [Indexed: 01/23/2023] Open
Abstract
Background: The purpose of this study is to elucidate mechanism(s) by which the orally active PGI2 analog, Beraprost (BPS), ameliorates pulmonary hypertension (PH). Prostaglandins are an important treatment for PH. Mechanisms of their action are not fully elucidated in relation to receptor subtype and effects on O2 sensitive Kv channels. Methods: Distal (3rd order and beyond) pulmonary arteries from chronically hypoxic rats and from humans with established PH were studied. Measurements included pulmonary haemodynamics and histology, vascular reactivity, prostanoid receptor expression and activity of the O2 sensitive Kv channels. Results: Prostacyclin receptor (IP), prostaglandin receptor E3 (EP3) and prostaglandin receptor E4 (EP4) are the main pulmonary artery receptor subtypes in both rat and human pulmonary arteries. Circulating levels of PGI2 and PGE2 were reduced in PH. PH was also associated with reduced receptor expression of IP but not of EP4. The effects on IP expression were overcome with BPS. Dilatory responses in PH to BPS were reduced in the presence of EP4 blockade. Expression and activity of oxygen sensitive Kv channels were reduced in pulmonary artery smooth muscle cell from rats with PH and humans with PAH and were also overcome by administration of BPS. Effects of BPS on oxygen sensitive Kv channels were reduced in the presence of EP4 blockade implicating the EP4 receptor, as well as the IP receptor, in mediating BPS effects. Conclusion: Reduced expression of pulmonary IP receptors and reduced activity of O2 sensitive Kv channels are found in PH in both humans and rats. The orally active prostacyclin analogue, BPS, is able to reverse these changes, partly through binding to the EP4 receptor.
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Affiliation(s)
- Fenling Fan
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Hua Tian
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Jie Geng
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Jizhao Deng
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Ya Liu
- Department of Respiratory, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Chunyan Chen
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Songlin Zhang
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Yushun Zhang
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Jie Li
- Department of Gynecology and Obstetrics, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Hongyan Tian
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Anthony M. Dart
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Cardiovascular Medicine, The Alfred Hospital, Melbourne, VIC, Australia
| | - Yuliang Zou
- Department of Gynecology and Obstetrics, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
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Alterations of ATP-sensitive K + channels in human umbilical arterial smooth muscle during gestational diabetes mellitus. Pflugers Arch 2018; 470:1325-1333. [PMID: 29855712 DOI: 10.1007/s00424-018-2154-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/11/2018] [Accepted: 05/09/2018] [Indexed: 12/20/2022]
Abstract
We investigated the alterations of ATP-sensitive K+ (KATP) channels in human umbilical arterial smooth muscle cells during gestational diabetes mellitus (GDM). The amplitude of the KATP current induced by application of the KATP channel opener pinacidil (10 μM) was reduced in the GDM group than in the control group. Pinacidil-induced vasorelaxation was also predominant in the normal group compared with the GDM group. Reverse transcription polymerase chain reaction and Western blot analysis suggested that the expression of KATP channel subunits such as Kir6.1, Kir6.2, and SUR2B were decreased in the GDM group relative to the normal group. The application of forskolin and adenosine, which activates protein kinase A (PKA) and thereby KATP channels, elicited KATP current in both the normal and GDM groups. However, the current amplitudes were not different between the normal and GDM groups. In addition, the expression levels of PKA subunits were not altered between the two groups. These results suggest that the reduction of KATP current and KATP channel-induced vasorelaxation are due to the decreased expression of KATP channels, not to the impairment of KATP-related signaling pathways.
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Lee CH, Dai ZK, Yen CT, Hsieh SL, Wu BN. KMUP-1 protects against streptozotocin-induced mesenteric artery dysfunction via activation of ATP-sensitive potassium channels. Pharmacol Rep 2018; 70:746-752. [PMID: 29936361 DOI: 10.1016/j.pharep.2018.02.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 01/11/2018] [Accepted: 02/19/2018] [Indexed: 01/16/2023]
Abstract
BACKGROUND Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia accompanied by impaired vascular and endothelial function. Activation of ATP-sensitive potassium (KATP) channels can protect endothelial function against hypertension and hyperglycemia. KMUP-1, a xanthine derivative, has been demonstrated to modulate K+-channel activity in smooth muscles. This study investigated protective mechanisms of KMUP-1 in impaired mesenteric artery (MA) reactivity in streptozotocin (STZ)-induced diabetic rats. METHODS Rats were divided into three groups: control, STZ (65 mg/kg, ip) and STZ + KMUP-1 (5 or 10 mg/kg/day, ip). MA reactivity was measured by dual wire myograph. MA smooth muscle cells (MASMCs) were enzymatically dissociated and the KATP currents recorded by a whole-cell patch-clamp technique. RESULTS STZ decreased MA KATP currents in a time-course dependent manner and achieved steady inhibition at day 14. In the MASMCs of STZ-treated rats, KMUP-1 partially recovered the KATP currents, suggesting that vascular KATP channels were activated by KMUP-1. K+ (80 mM KCl)-induced MA contractions in STZ-treated rats were higher than those of control rats. KMUP-1 significantly attenuated STZ-stimulated MA contractions in response to high K+, suggesting that KMUP-1 may partly restore the vascular reactivity of MAs. In addition, STZ decreased the expression of endothelial nitric oxide synthase (eNOS) and this effect was reversed by KMUP-1, suggesting that KMUP-1 could improve STZ-induced vascular endothelial dysfunction. CONCLUSION KMUP-1 prevents STZ impairment of MA reactivity, eNOS levels and KATP channels, and accordingly protects against vascular dysfunction in diabetic rats.
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Affiliation(s)
- Chien-Hsing Lee
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Zen-Kong Dai
- Department of Pediatrics, Division of Pediatric Cardiology and Pulmonology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Department of Pediatrics, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Cheng-Ting Yen
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Su-Ling Hsieh
- Department of Pharmacy, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Bin-Nan Wu
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
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Li H, Shin SE, Seo MS, An JR, Choi IW, Jung WK, Firth AL, Lee DS, Yim MJ, Choi G, Lee JM, Na SH, Park WS. The anti-diabetic drug dapagliflozin induces vasodilation via activation of PKG and Kv channels. Life Sci 2018; 197:46-55. [PMID: 29409796 DOI: 10.1016/j.lfs.2018.01.032] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/22/2018] [Accepted: 01/31/2018] [Indexed: 12/20/2022]
Abstract
AIM Considering the clinical efficacy of dapagliflozin in patients with type 2 DM and the pathophysiological relevance of Kv channels for vascular reactivity. We investigate the vasodilatory effect of dapagliflozin and related mechanisms using phenylephrine (Phe)-induced contracted aortic rings. MATERIAL AND METHODS Arterial tone measurement was performed in aortic smooth muscle. KEY FINDINGS Application of dapagliflozin induced vasodilation in a concentration-dependent manner. Pre-treatment with the BKCa channel inhibitor paxilline, the KATP channel inhibitor glibenclamide, and the Kir channel inhibitor Ba2+ did not change dapagliflozin-induced vasodilation. However, application of the Kv channels inhibitor 4-AP effectively inhibited dapagliflozin-induced vasodilation. Application of the Ca2+ channel inhibitor nifedipine and the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) pump inhibitor thapsigargin did not alter the vasodilatory effect of dapagliflozin. Moreover, the adenylyl cyclase inhibitor SQ 22536 and the protein kinase A (PKA) inhibitor KT 5720 had no effect on dapagliflozin-induced vasodilation. Although guanylyl cyclase inhibitors, NS 2028 and ODQ, did not reduce the vasodilatory effect of dapagliflozin, the protein kinase G (PKG) inhibitor KT 5823 effectively inhibited dapagliflozin-induced vasodilation. The vasodilatory effect of dapagliflozin was not affected by elimination of the endothelium. Furthermore, pretreatment with the nitric oxide synthase inhibitor L-NAME or the small-conductance Ca2+-activated K (SKCa) channel inhibitor apamin did not change the vasodilatory effect of dapagliflozin. SIGNIFICANCE We concluded that dapagliflozin induced vasodilation via the activation of Kv channels and PKG, and was independent of other K+ channels, Ca2+ channels, intracellular Ca2+, and the endothelium.
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Affiliation(s)
- Hongliang Li
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Sung Eun Shin
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Mi Seon Seo
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Jin Ryeol An
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Il-Whan Choi
- Department of Microbiology, Inje University College of Medicine, Busan 48516, South Korea
| | - Won-Kyo Jung
- Department of Biomedical Engineering, and Center for Marine-Integrated Biomedical Technology (BK21 Plus) Pukyong National University, Busan 608-737, South Korea
| | - Amy L Firth
- Department of Pulmonary, Critical Care and Sleep Medicine, University of Southern California, Keck School of Medicine, Los Angeles CA90033, USA
| | - Dae-Sung Lee
- Department of Applied Research, National Marine Biodiversity Institute of Korea, Seocheon 33662, South Korea
| | - Mi-Jin Yim
- Department of Applied Research, National Marine Biodiversity Institute of Korea, Seocheon 33662, South Korea
| | - Grace Choi
- Department of Applied Research, National Marine Biodiversity Institute of Korea, Seocheon 33662, South Korea
| | - Jeong Min Lee
- Department of Applied Research, National Marine Biodiversity Institute of Korea, Seocheon 33662, South Korea
| | - Sung Hun Na
- Institute of Medical Sciences, Department of Obstetrics and Gynecology, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon 24341, South Korea.
| | - Won Sun Park
- Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea.
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Jamieson KL, Endo T, Darwesh AM, Samokhvalov V, Seubert JM. Cytochrome P450-derived eicosanoids and heart function. Pharmacol Ther 2017; 179:47-83. [DOI: 10.1016/j.pharmthera.2017.05.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Khayat MT, Nayeem MA. The Role of Adenosine A 2A Receptor, CYP450s, and PPARs in the Regulation of Vascular Tone. BIOMED RESEARCH INTERNATIONAL 2017; 2017:1720920. [PMID: 28884118 PMCID: PMC5572598 DOI: 10.1155/2017/1720920] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/22/2017] [Accepted: 07/12/2017] [Indexed: 01/06/2023]
Abstract
Adenosine is an endogenous mediator involved in a myriad of physiologic functions, including vascular tone regulation. It is also implicated in some pathologic conditions. Four distinct receptor subtypes mediate the effects of adenosine, such as its role in the regulation of the vascular tone. Vascular tone regulation is a complex and continuous process which involves many mechanisms and mediators that are not fully disclosed. The vascular endothelium plays a pivotal role in regulating blood flow to and from all body organs. Also, the vascular endothelium is not merely a physical barrier; it is a complex tissue with numerous functions. Among adenosine receptors, A2A receptor subtype (A2AAR) stands out as the primary receptor responsible for the vasodilatory effects of adenosine. This review focuses on important effectors of the vascular endothelium, including adenosine, adenosine receptors, EETs (epoxyeicosatrienoic acids), HETEs (hydroxyeicosatetraenoic acids), PPARs (peroxisome proliferator-activated receptors), and KATP channels. Given the impact of vascular tone regulation in cardiovascular physiology and pathophysiology, better understanding of the mechanisms affecting it could have a significant potential for developing therapeutic agents for cardiovascular diseases.
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Affiliation(s)
- Maan T. Khayat
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV 26506, USA
- Department of Pharmaceutical Chemistry, School of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammed A. Nayeem
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV 26506, USA
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Fleming I. The factor in EDHF: Cytochrome P450 derived lipid mediators and vascular signaling. Vascul Pharmacol 2016; 86:31-40. [DOI: 10.1016/j.vph.2016.03.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/20/2016] [Accepted: 03/06/2016] [Indexed: 12/31/2022]
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10
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Brunt VE, Fujii N, Minson CT. Endothelial-derived hyperpolarization contributes to acetylcholine-mediated vasodilation in human skin in a dose-dependent manner. J Appl Physiol (1985) 2015; 119:1015-22. [PMID: 26384409 DOI: 10.1152/japplphysiol.00201.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 09/16/2015] [Indexed: 11/22/2022] Open
Abstract
Cutaneous acetylcholine (ACh)-mediated dilation is commonly used to assess microvascular function, but the mechanisms of dilation are poorly understood. Depending on dose and method of administration, nitric oxide (NO) and prostanoids are involved to varying extents and the roles of endothelial-derived hyperpolarizing factors (EDHFs) are unclear. In the present study, five incremental doses of ACh (0.01-100 mM) were delivered either as a 1-min bolus (protocol 1, n = 12) or as a ≥20-min continuous infusion (protocol 2, n = 10) via microdialysis fibers infused with 1) lactated Ringer, 2) tetraethylammonium (TEA) [a calcium-activated potassium channel (KCa) and EDHF inhibitor], 3) L-NNA+ketorolac [NO synthase (NOS) and cyclooxygenase (COX) inhibitors], and 4) TEA+L-NNA+Ketorolac. The hyperemic response was characterized as peak and area under the curve (AUC) cutaneous vascular conductance (CVC) for bolus infusions or plateau CVC for continuous infusions, and reported as %maximal CVC. In protocol 1, TEA, alone and combined with NOS+COX inhibition, attenuated peak CVC (100 mM Ringer 59 ± 6% vs. TEA 43 ± 5%, P < 0.05; L-NNA+ketorolac 35 ± 4% vs. TEA+L-NNA+ketorolac 25 ± 4%, P < 0.05) and AUC (Ringer 25,414 ± 3,528 vs. TEA 21,403 ± 3,416%·s, P < 0.05; L-NNA+ketorolac 25,628 ± 3,828%(.)s vs. TEA+L-NNA+ketorolac 20,772 ± 3,711%·s, P < 0.05), although these effects were only significant at the highest dose of ACh. At lower doses, TEA lengthened the total time of the hyperemic response (10 mM Ringer 609 ± 78 s vs. TEA 860 ± 67 s, P < 0.05). In protocol 2, TEA alone did not affect plateau CVC, but attenuated plateau in combination with NOS+COX inhibition (100 mM 50.4 ± 6.6% vs. 30.9 ± 6.3%, P < 0.05). Therefore, EDHFs contribute to cutaneous ACh-mediated dilation, but their relative contribution is altered by the dose and infusion procedure.
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Affiliation(s)
- Vienna E Brunt
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and
| | - Naoto Fujii
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
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Yang L, Mäki-Petäjä K, Cheriyan J, McEniery C, Wilkinson IB. The role of epoxyeicosatrienoic acids in the cardiovascular system. Br J Clin Pharmacol 2015; 80:28-44. [PMID: 25655310 PMCID: PMC4500322 DOI: 10.1111/bcp.12603] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/19/2015] [Accepted: 01/23/2015] [Indexed: 12/29/2022] Open
Abstract
There is increasing evidence suggesting that epoxyeicosatrienoic acids (EETs) play an important role in cardioprotective mechanisms. These include regulating vascular tone, modulating inflammatory responses, improving cardiomyocyte function and reducing ischaemic damage, resulting in attenuation of animal models of cardiovascular risk factors. This review discusses the current knowledge on the role of EETs in endothelium-dependent control of vascular tone in the healthy and in subjects with cardiovascular risk factors, and considers the pharmacological potential of targeting this pathway.
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Affiliation(s)
- L Yang
- Experimental Medicine and Immunotherapeutics, Department of Medicine, Box 110, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - K Mäki-Petäjä
- Experimental Medicine and Immunotherapeutics, Department of Medicine, Box 110, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - J Cheriyan
- Experimental Medicine and Immunotherapeutics, Department of Medicine, Box 110, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - C McEniery
- Experimental Medicine and Immunotherapeutics, Department of Medicine, Box 110, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - I B Wilkinson
- Experimental Medicine and Immunotherapeutics, Department of Medicine, Box 110, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
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12
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Frömel T, Fleming I. Whatever happened to the epoxyeicosatrienoic Acid-like endothelium-derived hyperpolarizing factor? The identification of novel classes of lipid mediators and their role in vascular homeostasis. Antioxid Redox Signal 2015; 22:1273-92. [PMID: 25330284 DOI: 10.1089/ars.2014.6150] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Cytochrome P450 (CYP) epoxygenases metabolize arachidonic acid (AA) to generate epoxyeicosatrienoic acids (EETs). The latter are biologically active and reported to act as an endothelium-derived hyperpolarizing factor as well as to affect angiogenic and inflammatory signaling pathways. RECENT ADVANCES In addition to AA, the CYP enzymes also metabolize the ω-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid and docosahexaenoic acid to generate bioactive lipid epoxide mediators. The latter can be more potent than the EETs, but their actions are under investigated. The ω3-epoxides, like the EETs, are metabolized by the soluble epoxide hydrolase (sEH) to corresponding diols, and epoxide hydrolase inhibition increases epoxide levels and demonstrates anti-hypertensive as well as anti-inflammatory effects. CRITICAL ISSUES It seems that the overall consequences of CYP activation largely depend on enzyme substrate preference and the endogenous ω-3/ω-6 PUFA ratio. FUTURE DIRECTIONS More studies combining PUFA profiling with cell signaling and disease studies are required to determine the spectrum of molecular pathways affected by the different ω-6 and ω-3 PUFA epoxides and diols. Such information may help improve dietary studies aimed at promoting health via ω-3 PUFA supplementation and/or sEH inhibition.
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Affiliation(s)
- Timo Frömel
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University , Frankfurt am Main, Frankfurt, Germany
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13
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Fleming I. The Pharmacology of the Cytochrome P450 Epoxygenase/Soluble Epoxide Hydrolase Axis in the Vasculature and Cardiovascular Disease. Pharmacol Rev 2014; 66:1106-40. [DOI: 10.1124/pr.113.007781] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Shahabi P, Siest G, Visvikis-siest S. Influence of inflammation on cardiovascular protective effects of cytochrome P450 epoxygenase-derived epoxyeicosatrienoic acids. Drug Metab Rev 2013; 46:33-56. [DOI: 10.3109/03602532.2013.837916] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Brunt VE, Fujii N, Minson CT. No independent, but an interactive, role of calcium-activated potassium channels in human cutaneous active vasodilation. J Appl Physiol (1985) 2013; 115:1290-6. [PMID: 23970531 DOI: 10.1152/japplphysiol.00358.2013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In human cutaneous microvasculature, endothelium-derived hyperpolarizing factors (EDHFs) account for a large portion of vasodilation associated with local stimuli. Thus we sought to determine the role of EDHFs in active vasodilation (AVD) to passive heating in two protocols. Whole body heating was achieved using water-perfused suits (core temperature increase of 0.8-1.0°C), and skin blood flow was measured using laser-Doppler flowmetry. In the first protocol, four sites were perfused continuously via microdialysis with: 1) control; 2) tetraethylammonium (TEA) to block calcium-activated potassium (KCa) channels, and thus the actions of EDHFs; 3) N-nitro-l-arginine methyl ester (l-NAME) to inhibit nitric oxide synthase (NOS); and 4) TEA + l-NAME (n = 8). Data are presented as percent maximal cutaneous vascular conductance (CVC). TEA had no effect on AVD (CVC during heated plateau: control 57.4 ± 4.9% vs. TEA 63.2 ± 5.2%, P = 0.27), indicating EDHFs are not obligatory. l-NAME attenuated plateau CVC to 33.7 ± 5.4% (P < 0.01 vs. control); while TEA + l-NAME augmented plateau CVC compared with l-NAME alone (49.7 ± 5.3%, P = 0.02). From these data, it appears combined blockade of EDHFs and NOS necessitates dilation through other means, possibly through inward rectifier (KIR) and/or ATP-sensitive (KATP) potassium channels. To test this second hypothesis, we measured AVD at the following sites (n = 8): 1) control, 2) l-NAME, 3) l-NAME + TEA, and 4) l-NAME + TEA + barium chloride (BaCl2; KIR and KATP blocker). The addition of BaCl2 to l-NAME + TEA reduced plateau CVC to 32.7 ± 6.6% (P = 0.02 vs. l-NAME + TEA), which did not differ from the l-NAME site. These data combined demonstrate a complex interplay between vasodilatory pathways, with cross-talk between NO, KCa channels, and KIR and/or KATP channels.
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Affiliation(s)
- Vienna E Brunt
- Department of Human Physiology, University of Oregon, Eugene, Oregon
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Ponnoth DS, Nayeem MA, Tilley SL, Ledent C, Jamal Mustafa S. CYP-epoxygenases contribute to A2A receptor-mediated aortic relaxation via sarcolemmal KATP channels. Am J Physiol Regul Integr Comp Physiol 2012; 303:R1003-10. [PMID: 23019210 DOI: 10.1152/ajpregu.00335.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Previously, we have shown that A(2A) adenosine receptor (A(2A)AR) mediates aortic relaxation via cytochrome P-450 (CYP)-epoxygenases. However, the signaling mechanism is not understood properly. We hypothesized that ATP-sensitive K(+) (K(ATP)) channels play an important role in A(2A)AR-mediated relaxation. Organ bath and Western blot experiments were done using isolated aorta from A(2A)KO and corresponding wild-type (WT) mice. Aortic rings from WT and A(2A) knockout (KO) mice were precontracted with submaximal dose of phenylephrine (PE, 10(-6) M), and concentration-response curves for pinacidil, cromakalim (nonselective K(ATP) openers), and diazoxide (mitochondrial K(ATP) opener) were obtained. Diazoxide did not have any relaxation effect on PE-precontracted tissues, whereas relaxation to pinacidil (48.09 ± 5.23% in WT vs. 25.41 ± 2.73% in A(2A)KO; P < 0.05) and cromakalim (51.19 ± 2.05% in WT vs. 38.50 ± 2.26% in A(2A)KO; P < 0.05) was higher in WT than A(2A)KO aorta. This suggested the involvement of sarcolemmal rather than mitochondrial K(ATP) channels. Endothelium removal, treatment with SCH 58651 (A(2A)AR antagonist; 10(-6) M), N(G)-nitro-l-arginine methyl ester (l-NAME, nitric oxide synthase inhibitor) and methylsulfonyl-propargyloxyphenylhexanamide (MS-PPOH, CYP-epoxygenases inhibitor; 10(-5) M) significantly reduced pinacidil-induced relaxation in WT compared with controls, whereas these treatments did not have any effect in A(2A)KO aorta. Glibenclamide (K(ATP) channel inhibitor, 10(-5) M) blocked 2-p-(2-carboxyethyl)phenethylamino-5'N-ethylcarboxamido adenosine hydrochloride (CGS 21680, A(2A)AR agonist)-induced relaxation in WT and changed 5'-N-ethylcarboxamide (NECA) (nonselective adenosine analog)-induced response to higher contraction in WT and A(2A)KO. 5-Hydroxydecanoate (5-HD, mitochondrial K(ATP) channel inhibitor, 10(-4) M) had no effect on CGS 21680-mediated response in WT aorta. Our data suggest that A(2A)AR-mediated vasorelaxation occurs through opening of sarcolemmal K(ATP) channels via CYP-epoxygenases and possibly, nitric oxide, contributing to pinacidil-induced responses.
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Affiliation(s)
- Dovenia S Ponnoth
- Dept of Physiology and Pharmacology, Center for Cardiovascular and Respiratory Sciences, West Virginia Univ., Morgantown, WV 26506, USA
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17
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Brunt VE, Minson CT. KCa channels and epoxyeicosatrienoic acids: major contributors to thermal hyperaemia in human skin. J Physiol 2012; 590:3523-34. [PMID: 22674719 DOI: 10.1113/jphysiol.2012.236398] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
While it is accepted that NO is responsible for ∼60% of the plateau in cutaneous thermal hyperaemia, a large portion of the response remains unknown. We sought to determine whether the remaining ∼40% could be attributed to EDHF-mediated activation of KCa channels, and whether the epoxyeicosatrienoic acids (EETs), derived via cytochrome P450, were the predominant EDHF active in the response. Four microdialysis fibres were placed in the forearm skin of 20 subjects. In Protocol 1 (n = 10): (1) Control, (2) N(G)-nitro-l-arginine methyl ester (l-NAME), (3) a KCa channel inhibitor, tetraethylammonium (TEA), and (4) TEA + l-NAME. In Protocol 2 (n = 10): (1) Control, (2) l-NAME, (3) a cytochrome P450 inhibitor, sulfaphenazole, and (4) sulfaphenazole + l-NAME. Local heating to 42°C was performed and skin blood flow was measured with laser Doppler flowmetry. Data are presented as the percentage of maximal cutaneous vascular conductance (CVC). All drug sites attenuated plateau CVC from the control site (86 ± 1%) to 79 ± 3% with sulfaphenazole (P = 0.02 from control), 71 ± 3% with TEA (P = 0.01 from control), and further to 38 ± 2% with l-NAME (P < 0.001 from control, P < 0.001 from TEA). Plateau was largely attenuated with sulfaphenazole + l-NAME (24 ± 2%; P = 0.002 from l-NAME), and nearly abolished with l-NAME + TEA (13 ± 2%; P = 0.001 from sulfaphenazole + l-NAME), which was not different from baseline (P = 0.14). Furthermore, the initial peak was just 17 ± 2% with TEA + l-NAME (P < 0.001 from l-NAME). These data suggest EDHFs are responsible for a large portion of initial peak and the remaining 40% of the plateau phase, as administration of TEA in combination with l-NAME abolished the majority of hyperaemia. These data also suggest EETs contribute to about half of the EDHF response.
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Affiliation(s)
- Vienna E Brunt
- Department of Human Physiology, University of Oregon, Eugene, OR 97403-1240, USA
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18
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Imig JD. Epoxides and soluble epoxide hydrolase in cardiovascular physiology. Physiol Rev 2012; 92:101-30. [PMID: 22298653 DOI: 10.1152/physrev.00021.2011] [Citation(s) in RCA: 272] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Epoxyeicosatrienoic acids (EETs) are arachidonic acid metabolites that importantly contribute to vascular and cardiac physiology. The contribution of EETs to vascular and cardiac function is further influenced by soluble epoxide hydrolase (sEH) that degrades EETs to diols. Vascular actions of EETs include dilation and angiogenesis. EETs also decrease inflammation and platelet aggregation and in general act to maintain vascular homeostasis. Myocyte contraction and increased coronary blood flow are the two primary EET actions in the heart. EET cell signaling mechanisms are tissue and organ specific and provide significant evidence for the existence of EET receptors. Additionally, pharmacological and genetic manipulations of EETs and sEH have demonstrated a contribution for this metabolic pathway to cardiovascular diseases. Given the impact of EETs to cardiovascular physiology, there is emerging evidence that development of EET-based therapeutics will be beneficial for cardiovascular diseases.
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Affiliation(s)
- John D Imig
- Department of Pharmacology and Toxicology, Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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Capra V, Bäck M, Barbieri SS, Camera M, Tremoli E, Rovati GE. Eicosanoids and Their Drugs in Cardiovascular Diseases: Focus on Atherosclerosis and Stroke. Med Res Rev 2012; 33:364-438. [DOI: 10.1002/med.21251] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Valérie Capra
- Department of Pharmacological Sciences; University of Milan; Via Balzaretti 9 20133 Milan Italy
| | - Magnus Bäck
- Department of Cardiology and Center for Molecular Medicine; Karolinska University Hospital; Stockholm Sweden
| | | | - Marina Camera
- Department of Pharmacological Sciences; University of Milan; Via Balzaretti 9 20133 Milan Italy
- Centro Cardiologico Monzino; I.R.C.C.S Milan Italy
| | - Elena Tremoli
- Department of Pharmacological Sciences; University of Milan; Via Balzaretti 9 20133 Milan Italy
- Centro Cardiologico Monzino; I.R.C.C.S Milan Italy
| | - G. Enrico Rovati
- Department of Pharmacological Sciences; University of Milan; Via Balzaretti 9 20133 Milan Italy
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20
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Liu Y, Zhang J, Yu L, Cao F, Rao J, Li J, Jiang C, Falck JR, Jacobs ER, Zhu D. A soluble epoxide hydrolase inhibitor--8-HUDE increases pulmonary vasoconstriction through inhibition of K(ATP) channels. Pulm Pharmacol Ther 2011; 25:69-76. [PMID: 22155000 DOI: 10.1016/j.pupt.2011.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 11/07/2011] [Accepted: 11/26/2011] [Indexed: 11/17/2022]
Abstract
Epoxyeicosatrienoic acids (EETs), cytochrome P450-derived metabolites of arachidonic acid, are endogenously produced epoxides that act as substrates for the soluble epoxide hydrolase (sEH). Recent studies indicate that EETs increase the tension of rat pulmonary arteries (PAs), and inhibition of sEH augments hypoxic pulmonary vasoconstriction. However, the mechanisms underlying the proconstrictive effects of sEH inhibitors in pulmonary artery smooth muscle cells (PASMCs) are unclear. In the present study, we used a sEH inhibitor, 12-(3-hexylureido) dodec-8-enoic acid (8-HUDE), to examine the ionic mechanisms underlying the constriction of PAs. 8-HUDE increased the tension of rat PAs to 145% baseline in a manner which was effectively eliminated by 10 μmol/L glibenclamide, an inhibitor of ATP-sensitive K(+) (K(ATP)) channels. Whole cell currents of HEK cells transfected with Kir6.1 or SUR2B were activated by K(ATP) channel opener pinacidil, inhibited by K(ATP) channel inhibitor glibenclamide or inhibited by 8-HUDE in a concentration-dependent manner with an IC50 value of 40 uM. In addition, 8-HUDE inhibited the expression of Kir6.1 and SUR2B at both mRNA and protein level in rat PASMCs. These observations suggest that 8-HUDE exerts acute effects on K(ATP) channel activity as well as subacute effects through decreased channel expression, and these effects are, at least in part, via the Kir6.1/SUR2B channel.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/pharmacology
- ATP-Binding Cassette Transporters/antagonists & inhibitors
- ATP-Binding Cassette Transporters/biosynthesis
- Animals
- Blotting, Western
- Cells, Cultured
- Enzyme Inhibitors/pharmacology
- Epoxide Hydrolases/antagonists & inhibitors
- Fatty Acids, Monounsaturated/pharmacology
- Female
- HEK293 Cells
- Humans
- KATP Channels/antagonists & inhibitors
- KATP Channels/biosynthesis
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Myocytes, Smooth Muscle/drug effects
- Patch-Clamp Techniques
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Inwardly Rectifying/antagonists & inhibitors
- Potassium Channels, Inwardly Rectifying/biosynthesis
- Pulmonary Artery/drug effects
- Pulmonary Circulation/drug effects
- Rats
- Rats, Wistar
- Real-Time Polymerase Chain Reaction
- Receptors, Drug/antagonists & inhibitors
- Receptors, Drug/biosynthesis
- Sulfonylurea Receptors
- Vasoconstriction/drug effects
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Yun Liu
- Department of Biopharmaceutical Key Laboratory of Heilongjiang Province, College of Pharmacy, Harbin Medical University, 157 Baojian Road, Nangang District, Harbin, Heilongjiang 150081, PR China
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21
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Wagner K, Inceoglu B, Hammock BD. Soluble epoxide hydrolase inhibition, epoxygenated fatty acids and nociception. Prostaglandins Other Lipid Mediat 2011; 96:76-83. [PMID: 21854866 DOI: 10.1016/j.prostaglandins.2011.08.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/28/2011] [Accepted: 08/02/2011] [Indexed: 01/17/2023]
Abstract
The soluble epoxide hydrolase (sEH) enzyme regulates the levels of endogenous epoxygenated fatty acid (EFA) lipid metabolites by rapidly degrading these molecules. The EFAs have pleiotropic biological activities including the modulation of nociceptive signaling. Recent findings indicate that the EFAs, in particular the arachidonic acid (AA) derived epoxyeicosatrienoic acids (EETs), the docosahexaenoic acid (DHA) derived epoxydocosapentaenoic acids (EpDPEs) and eicosapentaenoic acid (EPA) derived epoxyeicosatetraenoic acids (EpETEs) are natural signaling molecules. The tight regulation of these metabolites speaks to their importance in regulating biological functions. In the past several years work on EFAs in regard to their activities in the nervous system evolved to demonstrate that these molecules are anti-inflammatory and anti-nociceptive. Here we focus on the recent advances in understanding the effects of sEH inhibition and increased EFAs on the nociceptive system and their ability to reduce pain. Evidence of their role in modulating pain signaling is given by their direct application and by inhibiting their degradation in various models of pain. Moreover, there is mounting evidence of EFAs role in the crosstalk between major nociceptive and anti-nociceptive systems which is reviewed herein. Overall the fundamental knowledge generated within the past decade indicates that orally bioavailable small molecule inhibitors of sEH may find a place in the treatment of a number of diverse painful conditions including inflammatory and neuropathic pain.
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Affiliation(s)
- Karen Wagner
- Department of Entomology and UC Davis Cancer Center, University of California Davis, Davis, CA 95616, USA
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22
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Félétou M. The Endothelium, Part I: Multiple Functions of the Endothelial Cells -- Focus on Endothelium-Derived Vasoactive Mediators. ACTA ACUST UNITED AC 2011. [DOI: 10.4199/c00031ed1v01y201105isp019] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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23
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Pavlov TS, Ilatovskaya DV, Levchenko V, Mattson DL, Roman RJ, Staruschenko A. Effects of cytochrome P-450 metabolites of arachidonic acid on the epithelial sodium channel (ENaC). Am J Physiol Renal Physiol 2011; 301:F672-81. [PMID: 21697242 DOI: 10.1152/ajprenal.00597.2010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sodium reabsorption via the epithelial Na(+) channel (ENaC) in the aldosterone-sensitive distal nephron plays a central role in the regulation of body fluid volume. Previous studies have indicated that arachidonic acid (AA) and its metabolite 11,12-EET but not other regioisomers of EETs inhibit ENaC activity in the collecting duct. The goal of this study was to investigate the endogenous metabolism of AA in cultured mpkCCD(c14) principal cells and the effects of these metabolites on ENaC activity. Liquid chromatography/mass spectrometry analysis of the mpkCCD(c14) cells indicated that these cells produce prostaglandins, 8,9-EET, 11,12-EET, 14,15-EET, 5-HETE, 12/8-HETE, and 15-HETE, but not 20-HETE. Single-channel patch-clamp experiments revealed that 8,9-EET, 14,15-EET, and 11,12-EET all decrease ENaC activity. Neither 5-, 12-, nor 15-HETE had any effect on ENaC activity. Diclofenac and ibuprofen, inhibitors of cyclooxygenase, decreased transepithelial Na(+) transport in the mpkCCD(c14) cells. Inhibition of cytochrome P-450 (CYP450) with MS-PPOH activated ENaC-mediated sodium transport when cells were pretreated with AA and diclofenac. Coexpression of CYP2C8, but not CYP4A10, with ENaC in Chinese hamster ovary cells significantly decreased ENaC activity in whole-cell experiments, whereas 11,12-EET mimicked this effect. Thus both endogenously formed EETs and their exogenous application decrease ENaC activity. Downregulation of ENaC activity by overexpression of CYP2C8 was PKA dependent and was prevented by myristoylated PKI treatment. Biotinylation experiments and single-channel analysis revealed that long-term treatment with 11,12-EET and overexpression of CYP2C8 decreased the number of channels in the membrane. In contrast, the acute inhibitory effects are mediated by a decrease in the open probability of the ENaC. We conclude that 11,12-EET, 8,9-EET, and 14,15-EET are endogenously formed eicosanoids that modulate ENaC activity in the collecting duct.
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Affiliation(s)
- Tengis S Pavlov
- Dept. of Physiology, Medical College of Wisconsin, Milwaukee, 53226, USA
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25
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Nayeem MA, Zeldin DC, Boegehold MA, Morisseau C, Marowsky A, Ponnoth DS, Roush KP, Falck JR. Modulation by salt intake of the vascular response mediated through adenosine A(2A) receptor: role of CYP epoxygenase and soluble epoxide hydrolase. Am J Physiol Regul Integr Comp Physiol 2010; 299:R325-33. [PMID: 20427718 DOI: 10.1152/ajpregu.00823.2009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High-salt intake can change the effect of adenosine on arterial tone in mice. The aim of this study was to clarify the mechanism by which this occurs. Using aortas from mice fed a 4% NaCl (HS) or 0.45% NaCl (NS) diet for 4-5 wks, concentration-response curves for ACh, 5'-N-ethylcarboxamidoadenosine (NECA; adenosine analog) and 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride hydrate [CGS-21680; A(2A) adenosine receptor (A(2A) AR) agonist] were obtained with N(omega)-nitro-L-arginine methyl ester (L-NAME; nitric oxide inhibitor, 10(-4) M), methylsulfonyl-propargyloxyphenylhexanamide [MS-PPOH; a CYP (cytochrome P-450) epoxygenase blocker, 10(-5) M including CYP2J2], 12-(3-adamantan-1-yl-ureido)dodecanoic acid [AUDA; soluble epoxide hydrolase (sEH) blocker, 10(-5) M], dibromo-dodecenyl-methylsulfimide [DDMS; CYP omega-hydroxylase (CYP4A blocker), 10(-5) M], glibenclamide (K(ATP) channel blocker; 10(-5) M) and 5-hydroxydecanoate (5-HD; mitochondrial-K(ATP) channel blocker, 10(-4) M). HS dose response to ACh (10(-7) - 10(-5) M) was not different from NS (P > 0.05). Relaxation to 10(-6) M NECA was greater in the HS group (28.4 +/- 3.9%) than in the NS group (4.1 +/- 2.3%). Relaxation to 10(-6) M CGS-21680 was also greater in HS (27.9 +/- 4.5%) than in NS (4.9 +/- 2.2%). L-NAME was able to block the dose response of ACh (10(-7) - 10(-5) M) equally in both HS and NS (P > 0.05), whereas L-NAME did not block CGS-21680-induced response in HS. In HS the CGS-21680 response was greatly reduced by MS-PPOH (to 4.7 +/- 2.0%) and 5-HD (to 8.9 +/- 2.2%), and also abolished by glibenclamide (-1.0 +/- 5.9%). In NS, the CGS-21680 response was increased by AUDA (to 26.3 +/- 3.4%) and DDMS (to 27.2 +/- 3.0%). Compared with NS, HS vessels showed increased CYP2J2 and A(2A) AR expression (46 and 74% higher, respectively) but decreased sEH, CYP4A, and A(1) AR expression (75, 30, and 55% lower, respectively). These data suggest that in mice fed NS-containing diet, upregulation of arterial A(1) receptor causes vasoconstriction via increased sEH and CYP4A proteins. However, in mice fed HS-containing diet, upregulation of A(2A) receptor protein triggers vascular relaxation through ATP-sensitive (K(+)) channels via upregulation of CYP2J2 enzyme.
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Affiliation(s)
- Mohammed A Nayeem
- Department of Physiology and Pharmacology, Center for Cardiovascular and Respiratory Sciences, West Virginia University, Morgantown, West Virginia 26506, USA.
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26
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Campbell WB, Fleming I. Epoxyeicosatrienoic acids and endothelium-dependent responses. Pflugers Arch 2010; 459:881-95. [PMID: 20224870 DOI: 10.1007/s00424-010-0804-6] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 02/08/2010] [Accepted: 02/12/2010] [Indexed: 12/28/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are cytochrome P450 metabolites of arachidonic acid that are produced by the vascular endothelium in response to agonists such as bradykinin and acetylcholine or physical stimuli such as shear stress or cyclic stretch. In the vasculature, the EETs have biological actions that are involved in the regulation of vascular tone, hemostasis, and inflammation. In preconstricted arteries in vitro, EETs activate calcium-activated potassium channels on vascular smooth muscle and the endothelium causing membrane hyperpolarization and relaxation. These effects are observed in a variety of arteries from experimental animals and humans; however, this is not a universal finding in all arteries. The mechanism of EET action may vary. In some arteries, EETs are released from the endothelium and are transferred to the smooth muscle where they cause potassium channel activation, hyperpolarization, and relaxation through a guanine nucleotide binding protein-coupled mechanism or transient receptor potential (TRP) channel activation. In other arteries, EETs activate TRP channels on the endothelium to cause endothelial hyperpolarization that is transferred to the smooth muscle by gap junctions or potassium ion. Some arteries use a combination of mechanisms. Acetylcholine and bradykinin increase blood flow in dogs and humans that is inhibited by potassium channel blockers and cytochrome P450 inhibitors. Thus, the EETs are endothelium-derived hyperpolarizing factors mediating a portion of the relaxations to acetylcholine, bradykinin, shear stress, and cyclic stretch and regulate vascular tone in vitro and in vivo.
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Affiliation(s)
- William B Campbell
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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27
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Shi W, Cui N, Wu Z, Yang Y, Zhang S, Gai H, Zhu D, Jiang C. Lipopolysaccharides up-regulate Kir6.1/SUR2B channel expression and enhance vascular KATP channel activity via NF-kappaB-dependent signaling. J Biol Chem 2010; 285:3021-9. [PMID: 19959479 PMCID: PMC2823456 DOI: 10.1074/jbc.m109.058313] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 12/01/2009] [Indexed: 12/31/2022] Open
Abstract
Sepsis is a severe medical condition causing a large number of deaths worldwide. Recent studies indicate that the septic susceptibility is attributable to the vascular ATP-sensitive K(+) (K(ATP)) channel. However, the mechanisms underlying the channel modulation in sepsis are still unclear. Here we show evidence for the modulation of vascular K(ATP) channel by septic pathogen lipopolysaccharides (LPS). In isolated mesenteric arterial rings, phenylephrine (PE) produced concentration-dependent vasoconstriction that was relaxed by pinacidil, a selective K(ATP) channel opener. The PE response was disrupted with a LPS treatment. In acutely dissociated aortic smooth myocytes the LPS treatment augmented K(ATP) channel activity, and hyperpolarized the cells. Quantitative PCR analysis showed that LPS raised Kir6.1 and SUR2B transcripts in a concentration-dependent manner, which was suppressed by transcriptional inhibition. Consistently, the same LPS treatment did not affect Kir6.1/SUR2B channels in a heterologous expression system. The LPS effect on Kir6.1 and SUR2B expression was abolished in the presence of NF-kappaB inhibitors. Several other Toll-like receptor ligands also stimulated Kir6.1 and SUR2B expression to a similar degree as LPS. Thus, the effect of LPS on vasodilation involves up-regulation of K(ATP) channel expression, in which the NF-kappaB-dependent signaling plays an important role.
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Affiliation(s)
- Weiwei Shi
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Ningren Cui
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Zhongying Wu
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Yang Yang
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Shuang Zhang
- the School of Pharmacy, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Hongyu Gai
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
| | - Daling Zhu
- the School of Pharmacy, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Chun Jiang
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303 and
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Fan F, Ma A, Guan Y, Huo J, Hu Z, Tian H, Chen L, Zhu S, Fan L. Effect of PGE2 on DA tone by EP4 modulating Kv channels with different oxygen tension between preterm and term. Int J Cardiol 2009; 147:58-65. [PMID: 19729212 DOI: 10.1016/j.ijcard.2009.07.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Accepted: 07/24/2009] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To investigate common downstream mechanism of PGE2 and O2-sensitive voltage-dependent potassium (Kv) channels in preterm and term DA tone regulations, for suggesting respective prescriptions for preterm and term PDA. STUDY DESIGN The expressions of Kv1.2, 1.5 and 2.1 were compared between preterm and term in rabbit and human DAs at mRNA and protein levels; DA contracting responses caused by O2, Kv channels blocker 4-AP, EP4 antagonist GW627368X, and PGE2 reduce using vessels rings and Whole-Cell Patch-Clamp were explored. RESULTS Kv 1.2 and 2.1 expressions were developed with pregnant age in preterm DA and decreased after birth with oxygen stimulation in term DA. GW627368X led significant DA constriction and DASMC IK current decrease in preterm, which was slimier to 4-AP effects, but just slightly influenced on DA tension and DASMC IK current at term. In addition, PGE2 led great DA dilation and IK current increase of DASMC in preterm but not in term. These DA tension and IK current changes were in line with Kv channel expressions. CONCLUSION Higher levels of PGE2 binds with GPCR EP4, which activates G-protein to couple with O2-sensitive Kv channels and to open them, leading to DA vasorelaxation in the fetus. It indicates that EP4 inhibitors, instead of PGE2 or its analogue PGE1, may be a selectable strategy for preterm PDA.
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Affiliation(s)
- Fenling Fan
- The Cardiovascular Department of the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
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29
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Bodiga S, Zhang R, Jacobs DE, Larsen BT, Tampo A, Manthati VL, Kwok WM, Zeldin DC, Falck JR, Gutterman DD, Jacobs ER, Medhora MM. Protective actions of epoxyeicosatrienoic acid: dual targeting of cardiovascular PI3K and KATP channels. J Mol Cell Cardiol 2009; 46:978-88. [PMID: 19336274 DOI: 10.1016/j.yjmcc.2009.01.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 12/30/2008] [Accepted: 01/15/2009] [Indexed: 01/25/2023]
Abstract
Epoxyeicosatrienoic acid(s) (EETs) have been shown to protect cardiovascular tissue against apoptosis dependent on activation of targets such as ATP-sensitive K+ (KATP) channels (sarcolemmal and mitochondrial), calcium-activated K+ channels, extracellular signal-regulated kinase or phosphoinositide 3-kinase (PI3K). We tested if EETs protect human atrial tissue ex vivo from hypoxia/reoxygenation (H/R) injury, and compared our results with myocardium from two rodent species, rats and mice. EETs reduced myocardial caspase 3 activity in all three species and protected against loss of mitochondrial membrane potential in primary cultures of neonatal rat ventricular myocytes submitted to H/R. In addition, EETs protected mouse pulmonary arteries ex vivo exposed to H/R. Myocardium and pulmonary arteries from genetically engineered mice having elevated plasma levels of EETs (Ephx2-/-) exhibited protection from H/R-induced injury over that of wild type controls, suggesting that endogenously produced EETs may have pro-survival effects. Electrophysiological studies in myocytes demonstrated that EETs can stimulate KATP currents even when PI3K is inhibited. Similarly, activation of PI3K/Akt occurred in the presence of the KATP channel blocker glibenclamide. Based upon loss of protection with EETs in the presence of either wortmannin (a PI3K inhibitor) or glibenclamide, simultaneous activation of at least 2 pathways, PI3K and KATP channels respectively, appears to be required for protection. In conclusion, we demonstrate that exogenous and endogenous EETs have powerful pro-survival effects in cardiovascular tissues including diseased human myocardium, mediated by activation of not only one but at least two pathways, PI3K and KATP channels.
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Affiliation(s)
- Sreedhar Bodiga
- Pulmonary and Critical Care Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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30
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Fan LH, Tian HY, Wang J, Huo JH, Hu Z, Ma AQ, Cao YX. Downregulation of Kir6.1/SUR2B channels in the obese rat aorta. Nutrition 2008; 25:359-63. [PMID: 19056241 DOI: 10.1016/j.nut.2008.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 08/10/2008] [Accepted: 09/02/2008] [Indexed: 11/29/2022]
Abstract
OBJECTIVE This study was designed to evaluate the contribution of adenosine triphosphate-dependent potassium channels to the increase in blood pressure observed in obese rats. METHODS The experiment was performed in male Sprague-Dawley rats. Glibenclamide-sensitive currents were measured in vascular smooth muscle cells by patch-clamp. Expressions of Kir6.1 and SUR2B were examined by reverse transcription polymerase chain reaction and western blot techniques, respectively. RESULTS In the aortic vascular smooth muscle cells, pinacidil induced glibenclamide-sensitive currents. The current from obese rats was significantly lower (-10.55 +/- 1.63 pA/pF) compared with that from the control rats (-20.18 +/- 2.79 pA/pF). Expressions of Kir6.1 and SUR2B were downregulated in vascular smooth muscle cells of aortas from the obese rats. CONCLUSION These findings suggest that the adenosine triphosphate-dependent potassium channel is downregulated in smooth muscle cells from the aortas of obese rats, which may contribute to the increase in blood pressure in these rats.
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Affiliation(s)
- Li-Hong Fan
- Department of Cardiology, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
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31
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Fan LH, Tian HY, Ma AQ, Hu Z, Huo JH, Cao YX. Altered ATP-sensitive potassium channels may underscore obesity-triggered increase in blood pressure. Acta Pharmacol Sin 2008; 29:1167-74. [PMID: 18817620 DOI: 10.1111/j.1745-7254.2008.00810.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
AIM To determine whether ATP-sensitive potassium channels are altered in VSMC from arotas and mesenteric arteries of obese rat, and their association with obesity-triggered increase in blood pressure. METHODS Obesity was induced by 24 weeks of high-fat diet feeding in male Sprague-Dawley rats. Control rats were fed with standard laboratory rat chow. Blood pressure and body weight of these rats were measured every 4 weeks. At the end of 24 weeks, K(ATP) channelmediated relaxation responses in the aortas and mesenteric arteries, K(ATP) channel current, and gene expression were examined, respectively. RESULTS Blood pressure and body weight were increased in rats fed with high-fat diet. K(ATP) channelmediated relaxation responses, currents, and K(ATP) expression in VSMC of both aortas and mesenteric arteries were inhibited in these rats. CONCLUSION Altered ATP-sensitive potassium channels in obese rats may underscore obesity-triggered increase in blood pressure.
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Affiliation(s)
- Li-hong Fan
- Department of Cardiology, The First Affiliated Hospital of Xi-an Jiaotong University School of Medicine, Xi-an 710061, China
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32
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Roles of epoxyeicosatrienoic acids in vascular regulation and cardiac preconditioning. J Cardiovasc Pharmacol 2008; 50:601-8. [PMID: 18091575 DOI: 10.1097/fjc.0b013e318159cbe3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Continuing investigations of the roles of cytochrome P450 (CYP) arachidonic acid epoxygenase metabolites in the regulation of cardiovascular physiology and pathophysiology have revealed their complex and diverse biological effects. Often these metabolites demonstrate protective properties that are revealed during cardiovascular disease. In this regard, the epoxyeicosatrienoic acids (EETs) are an emerging target for pharmacological manipulation aimed at enhancing their cardiac and vascular protective mechanisms. This review will focus on the role of EETs in the regulation of vascular tone, with emphasis on the coronary circulation, their role in limiting platelet aggregation, vascular inflammation and EET contribution to preconditioning of the ischemic myocardium. Production and metabolism of EETs as well as their specific cellular signaling mechanisms are discussed.
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33
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Fan LH, Tian HY, Yang ML, Ma AQ, Hu Z, Bai XJ, Cao YX. High-fat diet may impair K(ATP) channels in vascular smooth muscle cells. Biomed Pharmacother 2008; 63:165-70. [PMID: 18339514 DOI: 10.1016/j.biopha.2008.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 01/09/2008] [Indexed: 11/25/2022] Open
Abstract
K(ATP) channel in vascular smooth muscle cell (VSMC) is closely linked to the etiology of hypertension. The aim of this study was to investigate effect of the high-fat diet-induced obesity on K(ATP) channel and blood pressure. Obesity was induced by a 24-week high-fat diet feeding in rats. Function and expression of K(ATP) channel in mesenteric arteries were examined using myography system, patch clamp and Western blotting. We show that high-fat diet increased blood pressure, decreased K(ATP) channel-mediated relaxation responses and currents, and down-regulated K(ATP) expression in VSMC. In conclusion, diet-induced obesity impairs K(ATP) channels in VSMC, which may underscore obesity-triggered increase in blood pressure.
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Affiliation(s)
- Li-Hong Fan
- Department of Cardiology, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710061, PR China
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34
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Hercule HC, Salanova B, Essin K, Honeck H, Falck JR, Sausbier M, Ruth P, Schunck WH, Luft FC, Gollasch M. The vasodilator 17,18-epoxyeicosatetraenoic acid targets the pore-forming BK alpha channel subunit in rodents. Exp Physiol 2007; 92:1067-76. [PMID: 17675416 DOI: 10.1113/expphysiol.2007.038166] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
17,18-Epoxyeicosatetraenoic acid (17,18-EETeTr) stimulates vascular large-conductance K(+) (BK) channels. BK channels are composed of the pore-forming BK alpha and auxiliary BK beta1 subunits that confer an increased sensitivity for changes in membrane potential and calcium to BK channels. Ryanodine-sensitive calcium-release channels (RyR3) in the sarcoplasmic reticulum (SR) control the process. To elucidate the mechanism of BK channel activation, we performed whole-cell and perforated-patch clamp experiments in freshly isolated cerebral and mesenteric artery vascular smooth muscle cells (VSMC) from Sprague-Dawley rats, BK beta1 gene-deficient (-/-), BK alpha (-/-), RyR3 (-/-) and wild-type mice. The 17,18-EETeTr (100 nm) increased tetraethylammonium (1 mm)-sensitive outward K(+) currents in VSMC from wild-type rats and wild-type mice. The effects were not inhibited by the epoxyeicosatrienoic acid (EET) antagonist 14,15-epoxyeicosa-5(Z)-enoic acid (10 mum). BK channel currents were increased 3.5-fold in VSMC from BK beta1 (-/-) mice, whereas a 2.9-fold stimulation was observed in VSMC from RyR3 (-/-) mice (at membrane voltage 60 mV). The effects were similar compared with those observed in cells from wild-type mice. The BK current increase was neither influenced by strong internal calcium buffering (Ca(2)(+), 100 nm), nor by external calcium influx. The 17,18-EETeTr did not induce outward currents in VSMC BK alpha (-/-) cells. We next tested the vasodilator effects of 17,18-EETeTr on isolated arteries of BK alpha-deficient mice. Vasodilatation was largely inhibited in cerebral and mesenteric arteries isolated from BK alpha (-/-) mice compared with that observed in wild-type and BK beta1 (-/-) arteries. We conclude that 17,18-EETeTr represents an endogenous BK channel agonist and vasodilator. Since 17,18-EETeTr is active in small arteries lacking BK beta1, the data further suggest that BK alpha represents the molecular target for the principal action of 17,18-EETeTr. Finally, the action of 17,18-EETeTr is not mediated by changes of the internal global calcium concentration or local SR calcium release events.
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Affiliation(s)
- Hantz C Hercule
- Nephrology/Hypertension Division, Franz Volhard Clinic, HELIOS Klinikum-Berlin, Campus Buch, Berlin, Germany
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35
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Shi Y, Wu Z, Cui N, Shi W, Yang Y, Zhang X, Rojas A, Ha BT, Jiang C. PKA phosphorylation of SUR2B subunit underscores vascular KATP channel activation by beta-adrenergic receptors. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1205-14. [PMID: 17596331 PMCID: PMC2258221 DOI: 10.1152/ajpregu.00337.2007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ATP-sensitive K(+) (K(ATP)) channels are activated by several vasodilating hormones and neurotransmitters through the PKA pathway. Here, we show that phosphorylation at Ser1387 of the SUR2B subunit is critical for the channel activation. Experiments were performed in human embryonic kidney (HEK) 293 cells expressing the cloned Kir6.1/SUR2B channel. In whole cell patch, the Kir6.1/SUR2B channel activity was stimulated by isoproterenol via activation of beta(2) receptors. This effect was blocked in the presence of inhibitors for adenylyl cyclase or PKA. Similar channel activation was seen by exposing inside-out patches to the catalytic subunit of PKA. Because none of the previously suggested PKA phosphorylation sites accounted for the channel activation, we performed systematic mutational analysis on Kir6.1 and SUR2B. Two serine residues (Ser1351, Ser1387) located in the NBD2 of SUR2B were critical for the channel activation. In vitro phosphorylation experiments showed that Ser1387 but not Ser1351 was phosphorylated by PKA. The PKA-dependent activation of cell-endogenous K(ATP) channels was observed in acutely dissociated mesenteric smooth myocytes and isolated mesenteric artery rings, where activation of these channels contributed significantly to the isoproterenol-induced vasodilation. Taken together, these results indicate that the Kir6.1/SUR2B channel is a target of beta(2) receptors and that the channel activation relies on PKA phosphorylation of SUR2B at Ser1387.
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MESH Headings
- ATP-Binding Cassette Transporters/metabolism
- Adrenergic beta-Agonists/pharmacology
- Amino Acid Sequence
- Animals
- Blood Vessels/drug effects
- Blood Vessels/metabolism
- Cell Line
- Colforsin/pharmacology
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Humans
- In Vitro Techniques
- Isoproterenol/pharmacology
- Molecular Sequence Data
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Patch-Clamp Techniques
- Phosphorylation
- Potassium Channels/metabolism
- Potassium Channels, Inwardly Rectifying/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/physiology
- Receptors, Drug/metabolism
- Sulfonylurea Receptors
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Affiliation(s)
- Yun Shi
- Department of Biology, Georgia State University, 24 Peachtree Center Ave., Atlanta, GA 30302, USA
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36
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Dimitropoulou C, West L, Field MB, White RE, Reddy LM, Falck JR, Imig JD. Protein phosphatase 2A and Ca2+-activated K+ channels contribute to 11,12-epoxyeicosatrienoic acid analog mediated mesenteric arterial relaxation. Prostaglandins Other Lipid Mediat 2006; 83:50-61. [PMID: 17259072 DOI: 10.1016/j.prostaglandins.2006.09.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 09/22/2006] [Accepted: 09/28/2006] [Indexed: 11/16/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are considered to be endothelium-derived hyperpolarizing factors, and are potent activators of the large-conductance, Ca(2+)-activated K(+) (BK(Ca)) channel in vascular smooth muscle. Here, we investigate the signal transduction pathway involved in the activation of BK(Ca) channels by 11,12-EET and 11,12-EET stable analogs in rat mesenteric vascular smooth muscle cells. 11,12-EET and the 11,12-EET analogs, 11-nonyloxy-undec-8(Z)-enoic acid (11,12-ether-EET-8-ZE), 11-(9-hydroxy-nonyloxy)-undec-8(Z)-enoic acid (11,12-ether-EET-8-ZE-OH) and 11,12-trans-oxidoeicosa-8(Z)-enoic acid (11,12-tetra-EET-8-ZE), caused vasorelaxation of mesenteric resistance arteries. Mesenteric myocyte whole-cell (perforated-patch) currents were substantially (approximately 150%) increased by 11,12-EET and 11,12-EET analogs. Single-channel recordings were conducted to identify the target for 11,12-EET. 11,12-EET and 11,12-EET analogs also increased mesenteric myocyte BK(Ca) channel activity in cell-attached patches. Similar results were obtained in cell-free patches. Baseline mesenteric myocyte BK(Ca) channel activity (NPo) in cell-free patches averaged less than 0.001 at +50 mV and 11,12-EET (1 micromol/L) increased NPo to 0.03+/-0.02 and 11,12-EET analogs (1 micromol/L) increased NPo to 0.09+/-0.006. Inhibition of protein phosphatase 2A (PP2A) activity with okadaic acid (10 nmol/L) completely reversed 11,12-EET stimulated BK(Ca) channel activity and greatly attenuated 11,12-ether-EET-8-ZE mesenteric resistance artery vasorelaxation. 11,12-EET and 11,12-EET analogs increased mesenteric myocyte PP2A activity by 3.5-fold. Okadaic acid and the EET inhibitor, 14,15-epoxyeicosa-5(Z)-enoic acid (14,15-EEZE) inhibited the 11,12-EET mediated increase in PP2A activity. These findings provide initial evidence that PP2A activity contributes to 11,12-EET and 11,12-EET analog activation of mesenteric resistant artery BK(Ca) channels and vasorelaxation.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/chemistry
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Animals
- Cells, Cultured
- Charybdotoxin/pharmacology
- Ion Channel Gating/drug effects
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
- Male
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/enzymology
- Muscle Cells/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Okadaic Acid/pharmacology
- Phosphoprotein Phosphatases/metabolism
- Potassium Channels/metabolism
- Potassium Channels, Calcium-Activated/metabolism
- Protein Phosphatase 2
- Rats
- Rats, Sprague-Dawley
- Vascular Resistance/drug effects
- Vasodilation/drug effects
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37
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McSherry IN, Sandow SL, Campbell WB, Falck JR, Hill MA, Dora KA. A role for heterocellular coupling and EETs in dilation of rat cremaster arteries. Microcirculation 2006; 13:119-30. [PMID: 16459325 DOI: 10.1080/10739680500466400] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVE The authors probed endothelium-dependent dilation and endothelial cell Ca2+ handling in myogenically active resistance arteries. METHODS First-order arteries were removed from rat cremaster muscles, cannulated, and pressurized (75 mmHg). Vessel diameter and endothelial cell Ca2+ were monitored using confocal microscopy, and arterial ultrastructure was determined using electron microscopy. RESULTS Acetylcholine (ACh) stimulated elevations and oscillations in endothelial cell Ca2+, and concentration-dependently dilated arteries with myogenic tone. NO-independent dilation was blocked by 35 mM K+. Combined IK(Ca) (1 microM TRAM-34) and SK(Ca) (100 nM apamin) blockade partially inhibited NO-independent relaxations, with residual relaxations sensitive to BK(Ca) or cytochrome P-450 inhibition (100 nM iberiotoxin, and 20 microM 17-ODYA or 10 microM MS-PPOH). 11,12-EET stimulated iberiotoxin-sensitive dilation, but did not affect endothelial cell Ca2+. 15 mM K+ evoked dilation sensitive to inhibition of K(IR) (30 microM Ba2+) and Na+/K+-ATPase (10 microM ouabain), whereas these blockers did not affect ACh-mediated dilations. Homo- and heterocellular gap junctions were identified in radial sections through arteries. CONCLUSION These data suggest that rises in endothelial cell Ca2+ stimulate SK(Ca) and IK(Ca) channels, leading to hyperpolarization and dilation, likely due to electrical coupling. In addition, a component was unmasked following SK(Ca) and IK(Ca) blockade, attributable to activation of BK(Ca) channels by cytochrome P-450 metabolites.
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MESH Headings
- Acetylcholine/pharmacology
- Animals
- Arteries/physiology
- Arteries/ultrastructure
- Calcium/metabolism
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Dose-Response Relationship, Drug
- Endothelium, Vascular/physiology
- Endothelium, Vascular/ultrastructure
- Enzyme Inhibitors/pharmacology
- Gap Junctions/metabolism
- Gap Junctions/ultrastructure
- Male
- Muscle, Smooth, Vascular/physiology
- Muscle, Smooth, Vascular/ultrastructure
- Potassium Channels, Calcium-Activated/antagonists & inhibitors
- Potassium Channels, Calcium-Activated/metabolism
- Rats
- Rats, Wistar
- Sodium-Potassium-Exchanging ATPase/antagonists & inhibitors
- Sodium-Potassium-Exchanging ATPase/metabolism
- Vasodilation/drug effects
- Vasodilation/physiology
- Vasodilator Agents/pharmacology
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38
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Lu T, Ye D, Wang X, Seubert JM, Graves JP, Bradbury JA, Zeldin DC, Lee HC. Cardiac and vascular KATP channels in rats are activated by endogenous epoxyeicosatrienoic acids through different mechanisms. J Physiol 2006; 575:627-44. [PMID: 16793897 PMCID: PMC1819457 DOI: 10.1113/jphysiol.2006.113985] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We have reported that epoxyeicosatrienoic acids (EETs), the cytochrome P450 (CYP) epoxygenase metabolites of arachidonic acid (AA), are potent sarcolemmal ATP-sensitive K+ (KATP) channel activators. However, activation of cardiac and vascular KATP channels by endogenously produced EETs under physiological intracellular conditions has not been demonstrated and direct comparison of the mechanisms whereby EETs activate the KATP channels in cardiac myocytes versus vascular smooth muscle cells has not been made. In this study, we examined the effects of AA on KATP channels in freshly isolated cardiac myocytes from rats, wild-type (WT) and transgenic mice overexpressing CYP2J2 cDNA, and mesenteric arterial smooth muscle cells from rats. We also compared the activation of cardiac and vascular KATP channels by extracellularly and intracellularly applied 11,12-EET. We found that 1 microm AA enhanced KATP channel activities in both cardiac and vascular smooth muscle cells, and the AA effects were inhibited by preincubation with CYP epoxygenase inhibitors. Baseline cardiac KATP current densities in CYP2J2 transgenic mice were 190% higher than those of WT mice, and both were reduced to similar levels by CYP epoxygenase inhibition. Western blot analysis showed that expression of Kir6.2 and SUR2A was similar between WT and CYP2J2 transgenic hearts. 11,12-EET (5 microm) applied intracellularly enhanced the KATP currents by 850% in cardiac myocytes, but had no effect in vascular smooth muscle cells. In contrast, 11,12-EET (5 microm) applied extracellularly increased KATP currents by 520% in mesenteric arterial smooth muscle cells, but by only 209% in cardiac myocytes. Preincubation with 100 microm m-iodobenzylguanidine or 5 microm myristoylated PKI amide did not alter the activation of cardiac KATP channels by 5 microm 11,12-EET, but significantly inhibited activation of vascular KATP channels. Moreover, EET only enhanced the inward component of cardiac KATP currents, but activated both the inward and outward components of vascular KATP currents. Our results indicate that endogenously derived CYP metabolites of AA potently activate cardiac and vascular KATP channels. EETs regulate cardiac electrophysiology and vascular tone by KATP channel activation, albeit through different mechanisms: the cardiac KATP channels are directly activated by EETs, whereas activation of the vascular KATP channels by EETs is protein kinase A dependent.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/metabolism
- Animals
- Arachidonic Acid/metabolism
- Arachidonic Acid/pharmacology
- Arteries/cytology
- Arteries/drug effects
- Arteries/metabolism
- Cyclic AMP-Dependent Protein Kinases/physiology
- Cytochrome P-450 CYP2J2
- Cytochrome P-450 Enzyme System/genetics
- Cytochrome P-450 Enzyme System/metabolism
- Gene Expression Regulation, Enzymologic/genetics
- Male
- Mice
- Mice, Transgenic
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Oxygenases/genetics
- Oxygenases/metabolism
- Potassium Channels/drug effects
- Potassium Channels/metabolism
- Rats
- Rats, Sprague-Dawley
- Vasodilator Agents/metabolism
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Affiliation(s)
- Tong Lu
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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39
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Rifkind AB. CYP1A in TCDD toxicity and in physiology-with particular reference to CYP dependent arachidonic acid metabolism and other endogenous substrates. Drug Metab Rev 2006; 38:291-335. [PMID: 16684662 DOI: 10.1080/03602530600570107] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Toxicologic and physiologic roles of CYP1A enzyme induction, the major biochemical effect of aryl hydrocarbon receptor activation by TCDD and other receptor ligands, are unknown. Evidence is presented that CYP1A exerts biologic effects via metabolism of endogenous substrates (i.e., arachidonic acid, other eicosanoids, estrogens, bilirubin, and melatonin), production of reactive oxygen, and effects on K(+) and Ca(2+) channels. These interrelated pathways may connect CYP1A induction to TCDD toxicities, including cardiotoxicity, vascular dysfunction, and wasting. They may also underlie homeostatic roles for CYP1A, especially when transiently induced by common chemical exposures and environmental conditions (i.e., tryptophan photoproducts, dietary indoles, and changes in oxygen tension).
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Affiliation(s)
- Arleen B Rifkind
- Department of Pharmacology, Weill Medical College of Cornell University, New York, NY 10021, USA.
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40
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Ye D, Zhou W, Lu T, Jagadeesh SG, Falck JR, Lee HC. Mechanism of rat mesenteric arterial KATP channel activation by 14,15-epoxyeicosatrienoic acid. Am J Physiol Heart Circ Physiol 2006; 290:H1326-36. [PMID: 16537788 DOI: 10.1152/ajpheart.00318.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recently, we reported that 11,12-epoxyeicosatrienoic acid (11,12-EET) potently activates rat mesenteric arterial ATP-sensitive K+ (KATP) channels and produces significant vasodilation through protein kinase A-dependent mechanisms. In this study, we tried to further delineate the signaling steps involved in the activation of vascular KATP channels by EETs. Whole cell patch-clamp recordings [0.1 mM ATP in the pipette, holding potential (HP) = 0 mV and testing potential (TP) = −100 mV] in freshly isolated rat mesenteric smooth muscle cells showed small glibenclamide-sensitive KATP currents (19.0 ± 7.9 pA, n = 5) that increased 6.9-fold on exposure to 5 μM 14,15-EET (132.0 ± 29.0 pA, n = 7, P < 0.05 vs. control). With 1 mM ATP in the pipette solution, KATP currents (HP = 0 mV and TP = −100 mV) were increased 3.5-fold on exposure to 1 μM 14,15-EET (57.5 ± 14.3 pA, n = 9, P < 0.05 vs. baseline). In the presence of 100 nM iberiotoxin, 1 μM 14,15-EET hyperpolarized the membrane potential from −20.5 ± 0.9 mV at baseline to −27.1 ± 3.0 mV ( n = 6 for both, P < 0.05 vs. baseline), and the EET effects were significantly reversed by 10 μM glibenclamide (−21.8 ± 1.4 mV, n = 6, P < 0.05 vs. EET). Incubation with 5 μM 14,15-epoxyeicosa-5( Z)-enoic acid (14,15-EEZE), a 14,15-EET antagonist, abolished the 14,15-EET effects (31.0 ± 11.8 pA, n = 5, P < 0.05 vs. 14,15-EET, P = not significant vs. control). The 14,15-EET effects were inhibited by inclusion of anti-Gsα antibody (1:500 dilution) but not by control IgG in the pipette solution. The effects of 14,15-EET were mimicked by cholera toxin (100 ng/ml), an exogenous ADP-ribosyltransferase. Treatment with the ADP-ribosyltransferase inhibitors 3-aminobenzamide (1 mM) or m-iodobenzylguanidine (100 μM) abrogated the effects of 14,15-EET on KATP currents. These results were corroborated by vasodilation studies. 14,15-EET dose-dependently dilated isolated small mesenteric arteries, and this was significantly attenuated by treatment with 14,15-EEZE or 3-aminobenzamide. These results suggest that 14,15-EET activates vascular KATP channels through ADP-ribosylation of Gsα.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Animals
- Cells, Cultured
- Ion Channel Gating/drug effects
- Ion Channel Gating/physiology
- Male
- Mesenteric Arteries/cytology
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Potassium Channels/drug effects
- Potassium Channels/metabolism
- Rats
- Rats, Sprague-Dawley
- Vasodilation/drug effects
- Vasodilation/physiology
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Dan Ye
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA
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Earley S, Heppner TJ, Nelson MT, Brayden JE. TRPV4 Forms a Novel Ca
2+
Signaling Complex With Ryanodine Receptors and BK
Ca
Channels. Circ Res 2005; 97:1270-9. [PMID: 16269659 DOI: 10.1161/01.res.0000194321.60300.d6] [Citation(s) in RCA: 362] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vasodilatory factors produced by the endothelium are critical for the maintenance of normal blood pressure and flow. We hypothesized that endothelial signals are transduced to underlying vascular smooth muscle by vanilloid transient receptor potential (TRPV) channels. TRPV4 message was detected in RNA from cerebral artery smooth muscle cells. In patch-clamp experiments using freshly isolated cerebral myocytes, outwardly rectifying whole-cell currents with properties consistent with those of expressed TRPV4 channels were evoked by the TRPV4 agonist 4alpha-phorbol 12,13-didecanoate (4alpha-PDD) (5 micromol/L) and the endothelium-derived arachidonic acid metabolite 11,12 epoxyeicosatrienoic acid (11,12 EET) (300 nmol/L). Using high-speed laser-scanning confocal microscopy, we found that 11,12 EET increased the frequency of unitary Ca2+ release events (Ca2+ sparks) via ryanodine receptors located on the sarcoplasmic reticulum of cerebral artery smooth muscle cells. EET-induced Ca2+ sparks activated nearby sarcolemmal large-conductance Ca2+-activated K+ (BKCa) channels, measured as an increase in the frequency of transient K+ currents (referred to as "spontaneous transient outward currents" [STOCs]). 11,12 EET-induced increases in Ca2+ spark and STOC frequency were inhibited by lowering external Ca2+ from 2 mmol/L to 10 micromol/L but not by voltage-dependent Ca2+ channel inhibitors, suggesting that these responses require extracellular Ca2+ influx via channels other than voltage-dependent Ca2+ channels. Antisense-mediated suppression of TRPV4 expression in intact cerebral arteries prevented 11,12 EET-induced smooth muscle hyperpolarization and vasodilation. Thus, we conclude that TRPV4 forms a novel Ca2+ signaling complex with ryanodine receptors and BKCa channels that elicits smooth muscle hyperpolarization and arterial dilation via Ca2+-induced Ca2+ release in response to an endothelial-derived factor.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Animals
- Calcium/metabolism
- Calcium Signaling
- Cerebral Arteries/chemistry
- Large-Conductance Calcium-Activated Potassium Channels/physiology
- Male
- Muscle, Smooth, Vascular/chemistry
- Muscle, Smooth, Vascular/physiology
- Myocytes, Smooth Muscle/physiology
- Rats
- Rats, Sprague-Dawley
- Ryanodine Receptor Calcium Release Channel/physiology
- TRPV Cation Channels/analysis
- TRPV Cation Channels/physiology
- Vasodilation/drug effects
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Affiliation(s)
- Scott Earley
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, VT 05405, USA.
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42
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Affiliation(s)
- W A Cupples
- Centre for Biomedical Research, Department of Biology, University of Victoria, PO Box 3020, STN CSC Victoria, British Columbia, Canada V8W 3N5.
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