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Liu T, Dogan I, Rothe M, Kunz JV, Knauf F, Gollasch M, Luft FC, Gollasch B. Hemodialysis and biotransformation of erythrocyte epoxy fatty acids in peripheral tissue. Prostaglandins Leukot Essent Fatty Acids 2022; 181:102453. [PMID: 35633593 DOI: 10.1016/j.plefa.2022.102453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 05/05/2022] [Accepted: 05/19/2022] [Indexed: 11/28/2022]
Abstract
Cardiovascular disease is the leading cause of mortality in patients with renal failure. Red blood cells (RBCs) are potential reservoirs for epoxy fatty acids (oxylipins) that regulate cardiovascular function. Hemoglobin exhibits pseudo-lipoxygenase activity in vitro. We previously assessed the impact of single hemodialysis (HD) treatment on RBC epoxy fatty acids status in circulating arterial blood and found that eicosanoids in oxygenated RBCs could be particularly vulnerable in chronic kidney disease and hemodialysis. The purpose of the present study was to evaluate the differences of RBC epoxy fatty acids profiles in arterial and venous blood in vivo (AV differences) from patients treated by HD treatment. We collected arterial and venous blood samples in upper limbs from 12 end-stage renal disease (ESRD) patients (age 72±12 years) before and after HD treatment. We measured oxylipins derived from cytochrome P450 (CYP) monooxygenase and lipoxygenase (LOX)/CYP ω/(ω-1)-hydroxylase pathways in RBCs by LC-MS/MS tandem mass spectrometry. Our data demonstrate arteriovenous differences in LOX pathway metabolites in RBCs after dialysis, including numerous hydroxyeicosatetraenoic acids (HETEs), hydroxydocosahexaenoic acids (HDHAs) and hydroxyeicosapentaenoic acids (HEPEs). We detected more pronounced changes in free metabolites in RBCs after HD, as compared with the total RBC compartment. Hemodialysis treatment did not affect the majority of CYP and CYP ω/(ω-1)-hydroxylase products in RBCs. Our data indicate that erythro-metabolites of the LOX pathway are influenced by renal-replacement therapies, which could have deleterious effects in the circulation.
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Affiliation(s)
- Tong Liu
- Experimental and Clinical Research Center (ECRC), a joint institution of the Charité Medical Faculty and Max Delbrück Center (MDC) for Molecular Medicine, Berlin 13125, Germany
| | - Inci Dogan
- LIPIDOMIX GmbH, Robert-Rössle-Str. 10, Berlin 13125, Germany
| | - Michael Rothe
- LIPIDOMIX GmbH, Robert-Rössle-Str. 10, Berlin 13125, Germany
| | - Julius V Kunz
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin 13353
| | - Felix Knauf
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin 13353
| | - Maik Gollasch
- Department of Internal Medicine and Geriatrics, University Medicine Greifswald, Greifswald 17475, Germany
| | - Friedrich C Luft
- Experimental and Clinical Research Center (ECRC), a joint institution of the Charité Medical Faculty and Max Delbrück Center (MDC) for Molecular Medicine, Berlin 13125, Germany
| | - Benjamin Gollasch
- Experimental and Clinical Research Center (ECRC), a joint institution of the Charité Medical Faculty and Max Delbrück Center (MDC) for Molecular Medicine, Berlin 13125, Germany; Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin 13353; HELIOS Klinikum Berlin-Buch, Schwanebecker Chaussee 50, Berlin 13125, Germany.
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Abstract
Supplemental Digital Content is available in the text. This is the largest study describing the role of P450 epoxygenase metabolites in septic shock in humans and suggests a novel therapeutic target.
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Liu T, Dogan I, Rothe M, Kunz JV, Knauf F, Gollasch M, Luft FC, Gollasch B. Hemodialysis and Plasma Oxylipin Biotransformation in Peripheral Tissue. Metabolites 2022; 12:metabo12010034. [PMID: 35050156 PMCID: PMC8781597 DOI: 10.3390/metabo12010034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 02/04/2023] Open
Abstract
Factors causing the increased cardiovascular morbidity and mortality in hemodialysis (HD) patients are largely unknown. Oxylipins are a superclass of lipid mediators with potent bioactivities produced from oxygenation of polyunsaturated fatty acids. We previously assessed the impact of HD on oxylipins in arterial blood plasma and found that HD increases several oxylipins. To study the phenomenon further, we now evaluated the differences in arterial and venous blood oxylipins from patients undergoing HD. We collected arterial and venous blood samples in upper extremities from 12 end-stage renal disease (ESRD) patients before and after HD and measured oxylipins in plasma by LC-MS/MS tandem mass spectrometry. Comparison between cytochrome P450 (CYP), lipoxygenase (LOX), and LOX/CYP ω/(ω-1)-hydroxylase metabolites levels from arterial and venous blood showed no arteriovenous differences before HD but revealed arteriovenous differences in several CYP metabolites immediately after HD. These changes were explained by metabolites in the venous blood stream of the upper limb. Decreased soluble epoxide hydrolase (sEH) activity contributed to the release and accumulation of the CYP metabolites. However, HD did not affect arteriovenous differences of the majority of LOX and LOX/CYP ω/(ω-1)-hydroxylase metabolites. The HD treatment itself causes changes in CYP epoxy metabolites that could have deleterious effects in the circulation.
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Affiliation(s)
- Tong Liu
- Experimental and Clinical Research Center (ECRC), Charité Medical Faculty and Max Delbrück Center (MDC) for Molecular Medicine, 13125 Berlin, Germany; (T.L.); (M.G.); (F.C.L.)
| | - Inci Dogan
- LIPIDOMIX GmbH, Robert-Rössle-Str. 10, 13125 Berlin, Germany; (I.D.); (M.R.)
| | - Michael Rothe
- LIPIDOMIX GmbH, Robert-Rössle-Str. 10, 13125 Berlin, Germany; (I.D.); (M.R.)
| | - Julius V. Kunz
- Department of Nephrology and Medical Intensive Care, Charité—Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany; (J.V.K.); (F.K.)
| | - Felix Knauf
- Department of Nephrology and Medical Intensive Care, Charité—Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany; (J.V.K.); (F.K.)
| | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC), Charité Medical Faculty and Max Delbrück Center (MDC) for Molecular Medicine, 13125 Berlin, Germany; (T.L.); (M.G.); (F.C.L.)
- Department of Internal Medicine and Geriatrics, University Medicine Greifswald, 17475 Greifswald, Germany
| | - Friedrich C. Luft
- Experimental and Clinical Research Center (ECRC), Charité Medical Faculty and Max Delbrück Center (MDC) for Molecular Medicine, 13125 Berlin, Germany; (T.L.); (M.G.); (F.C.L.)
| | - Benjamin Gollasch
- Experimental and Clinical Research Center (ECRC), Charité Medical Faculty and Max Delbrück Center (MDC) for Molecular Medicine, 13125 Berlin, Germany; (T.L.); (M.G.); (F.C.L.)
- HELIOS Klinikum Berlin-Buch, Schwanebecker Chaussee 50, 13125 Berlin, Germany
- Correspondence: ; Tel.: +49-30-450-540-249
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4
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Lu T, Lee HC. Coronary Large Conductance Ca 2+-Activated K + Channel Dysfunction in Diabetes Mellitus. Front Physiol 2021; 12:750618. [PMID: 34744789 PMCID: PMC8567020 DOI: 10.3389/fphys.2021.750618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/14/2021] [Indexed: 11/24/2022] Open
Abstract
Diabetes mellitus (DM) is an independent risk of macrovascular and microvascular complications, while cardiovascular diseases remain a leading cause of death in both men and women with diabetes. Large conductance Ca2+-activated K+ (BK) channels are abundantly expressed in arteries and are the key ionic determinant of vascular tone and organ perfusion. It is well established that the downregulation of vascular BK channel function with reduced BK channel protein expression and altered intrinsic BK channel biophysical properties is associated with diabetic vasculopathy. Recent efforts also showed that diabetes-associated changes in signaling pathways and transcriptional factors contribute to the downregulation of BK channel expression. This manuscript will review our current understandings on the molecular, physiological, and biophysical mechanisms that underlie coronary BK channelopathy in diabetes mellitus.
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Affiliation(s)
- Tong Lu
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, United States
| | - Hon-Chi Lee
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, United States
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Liang N, Hennebelle M, Gaul S, Johnson CD, Zhang Z, Kirpich IA, McClain CJ, Feldstein AE, Ramsden CE, Taha AY. Feeding mice a diet high in oxidized linoleic acid metabolites does not alter liver oxylipin concentrations. Prostaglandins Leukot Essent Fatty Acids 2021; 172:102316. [PMID: 34403987 PMCID: PMC9157566 DOI: 10.1016/j.plefa.2021.102316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 06/11/2021] [Accepted: 06/17/2021] [Indexed: 11/19/2022]
Abstract
The oxidation of dietary linoleic acid (LA) produces oxidized LA metabolites (OXLAMs) known to regulate multiple signaling pathways in vivo. Recently, we reported that feeding OXLAMs to mice resulted in liver inflammation and apoptosis. However, it is not known whether this is due to a direct effect of OXLAMs accumulating in the liver, or to their degradation into bioactive shorter chain molecules (e.g. aldehydes) that can provoke inflammation and related cascades. To address this question, mice were fed a low or high LA diet low in OXLAMs, or a low LA diet supplemented with OXLAMs from heated corn oil (high OXLAM diet). Unesterified oxidized fatty acids (i.e. oxylipins), including OXLAMs, were measured in liver after 8 weeks of dietary intervention using ultra-high pressure liquid chromatography coupled to tandem mass-spectrometry. The high OXLAM diet did not alter liver oxylipin concentrations compared to the low LA diet low in OXLAMs. Significant increases in several omega-6 derived oxylipins and reductions in omega-3 derived oxylipins were observed in the high LA dietary group compared to the low LA group. Our findings suggest that dietary OXLAMs do not accumulate in liver, and likely exert pro-inflammatory and pro-apoptotic effects via downstream secondary metabolites.
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Affiliation(s)
- Nuanyi Liang
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California Davis, Davis, CA, Unites States
| | - Marie Hennebelle
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California Davis, Davis, CA, Unites States
| | - Susanne Gaul
- Department of Pediatrics, University of California San Diego, La Jolla, CA, Unites States; Klinik und Poliklinik für Kardiologie, University Hospital Leipzig, Leipzig University, Germany
| | - Casey D Johnson
- Department of Pediatrics, University of California San Diego, La Jolla, CA, Unites States
| | - Zhichao Zhang
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California Davis, Davis, CA, Unites States
| | - Irina A Kirpich
- Division of Gastroenterology, Hepatology, and Nutrition, University of Louisville, Louisville, KY; Hepatobiology and Toxicology Program, University of Louisville, Louisville, KY; Department of Pharmacology and Toxicology and University of Louisville Alcohol Center
| | - Craig J McClain
- Division of Gastroenterology, Hepatology, and Nutrition, University of Louisville, Louisville, KY; Hepatobiology and Toxicology Program, University of Louisville, Louisville, KY; Department of Pharmacology and Toxicology and University of Louisville Alcohol Center; Veterans Affairs San Diego Healthcare System, San Diego, CA; and Robley Rex Veterans Medical Center, Louisville, KY
| | - Ariel E Feldstein
- Department of Pediatrics, University of California San Diego, La Jolla, CA, Unites States
| | - Christopher E Ramsden
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, Unites States; National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
| | - Ameer Y Taha
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California Davis, Davis, CA, Unites States.
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Kato Y, Senda A, Mukai Y, Yamashita M, Sasaoka Y, Hanada M, Hongo F, Hirokami M, Rane A, Inotsume N, Toda T. Effects of angiotensin II receptor blockers on serum levels of epoxyeicosatrienoic acids and dihydroxyeicosatrienoic acids in patients admitted to a cardiovascular center. Eur J Clin Pharmacol 2021; 77:887-894. [PMID: 33409683 PMCID: PMC8128744 DOI: 10.1007/s00228-020-03061-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 12/02/2020] [Indexed: 11/19/2022]
Abstract
Purpose Several clinical studies have demonstrated that angiotensin-converting enzyme inhibitors, but not angiotensin II receptor blockers (ARBs), reduce the risk of non-fatal myocardial infarction and cardiovascular mortality. We found that ARBs inhibited the activity of various cytochrome enzymes in arachidonic acid metabolism, resulting in decreased in vitro production of epoxyeicosatrienoic acids (EETs), which exhibit vasodilation and anti-inflammatory effects, and their subsequent metabolites, dihydroxyeicosatrienoic acids (DHETs). The present study examined the effects of ARBs on serum levels of EETs and DHETs in patients admitted to a cardiovascular center. Methods A total of 223 patients were enrolled, of which 107 were exposed to ARBs in this study. ARB-free individuals were defined as the control group (n = 116). Serum levels of EETs and DHETs were measured by liquid chromatography–tandem mass spectrometry. Multiple linear regression analyses were carried out to identify covariates for total serum levels of EETs and DHETs. Results A significant negative association was observed between ARB use and serum EET and DHET levels (p = 0.034), whereas a significant positive association was observed between the estimated glomerular filtration rate (eGFR) and serum EET and DHET levels (p = 0.007). The median serum total EET and DHET level in the ARB group tended to become lower than that in the control group, although the difference was not significant. Conclusion ARB use and eGFR were significantly associated with total serum levels of EETs and DHETs. Our results suggest that ARBs could affect the concentration of EETs in vivo. Supplementary Information The online version contains supplementary material available at 10.1007/s00228-020-03061-1.
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Affiliation(s)
- Yuka Kato
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Hokkaido University of Science, Sapporo, Japan
| | - Asuna Senda
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Hokkaido University of Science, Sapporo, Japan
| | - Yuji Mukai
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Hokkaido University of Science, Sapporo, Japan
| | - Miki Yamashita
- Department of Clinical Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University of Science, Sapporo, Japan
| | - Yuki Sasaoka
- Department of Pharmacy, Teine Keijinkai Hospital, Sapporo, Japan.,Department of Pharmacy, Sapporo Keijinkai Rehabilitation Hospital, Sapporo, Japan
| | - Minayo Hanada
- Department of Pharmacy, Teine Keijinkai Hospital, Sapporo, Japan
| | - Fuminori Hongo
- Department of Pharmacy, Teine Keijinkai Hospital, Sapporo, Japan
| | | | - Anders Rane
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Nobuo Inotsume
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Hokkaido University of Science, Sapporo, Japan.,Nihon Pharmaceutical University, Saitama, Japan
| | - Takaki Toda
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Hokkaido University of Science, Sapporo, Japan.
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O'Connell TD, Mason RP, Budoff MJ, Navar AM, Shearer GC. Mechanistic insights into cardiovascular protection for omega-3 fatty acids and their bioactive lipid metabolites. Eur Heart J Suppl 2020; 22:J3-J20. [PMID: 33061864 PMCID: PMC7537803 DOI: 10.1093/eurheartj/suaa115] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Patients with well-controlled low-density lipoprotein cholesterol levels, but persistent high triglycerides, remain at increased risk for cardiovascular events as evidenced by multiple genetic and epidemiologic studies, as well as recent clinical outcome trials. While many trials of low-dose ω3-polyunsaturated fatty acids (ω3-PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) have shown mixed results to reduce cardiovascular events, recent trials with high-dose ω3-PUFAs have reignited interest in ω3-PUFAs, particularly EPA, in cardiovascular disease (CVD). REDUCE-IT demonstrated that high-dose EPA (4 g/day icosapent-ethyl) reduced a composite of clinical events by 25% in statin-treated patients with established CVD or diabetes and other cardiovascular risk factors. Outcome trials in similar statin-treated patients using DHA-containing high-dose ω3 formulations have not yet shown the benefits of EPA alone. However, there are data to show that high-dose ω3-PUFAs in patients with acute myocardial infarction had reduced left ventricular remodelling, non-infarct myocardial fibrosis, and systemic inflammation. ω3-polyunsaturated fatty acids, along with their metabolites, such as oxylipins and other lipid mediators, have complex effects on the cardiovascular system. Together they target free fatty acid receptors and peroxisome proliferator-activated receptors in various tissues to modulate inflammation and lipid metabolism. Here, we review these multifactorial mechanisms of ω3-PUFAs in view of recent clinical findings. These findings indicate physico-chemical and biological diversity among ω3-PUFAs that influence tissue distributions as well as disparate effects on membrane organization, rates of lipid oxidation, as well as various receptor-mediated signal transduction pathways and effects on gene expression.
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Affiliation(s)
- Timothy D O'Connell
- Department of Integrative Biology and Physiology, University of Minnesota, 3-141 CCRB, 2231 6th Street SE, Minneapolis, MN 55414, USA
| | - Richard Preston Mason
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Matthew J Budoff
- Cardiovascular Division, Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Ann Marie Navar
- Cardiovascular Division, Duke Clinical Research Institute, Duke University, Durham, NC, USA
| | - Gregory C Shearer
- Department of Nutritional Sciences, The Pennsylvania State University, 110 Chandlee Laboratory, University Park, PA 16802, USA
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Gollasch B, Wu G, Liu T, Dogan I, Rothe M, Gollasch M, Luft FC. Hemodialysis and erythrocyte epoxy fatty acids. Physiol Rep 2020; 8:e14601. [PMID: 33112511 PMCID: PMC7592498 DOI: 10.14814/phy2.14601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/13/2020] [Accepted: 09/14/2020] [Indexed: 12/24/2022] Open
Abstract
Fatty acid products derived from cytochromes P450 (CYP) monooxygenase and lipoxygenase (LOX)/CYP ω/(ω-1)-hydroxylase pathways are a superclass of lipid mediators with potent bioactivities. Whether or not the chronic kidney disease (CKD) and hemodialysis treatments performed on end-stage renal disease (ESRD) patients affect RBC epoxy fatty acids profiles remains unknown. Measuring the products solely in plasma is suboptimal. Since such determinations invariably ignore red blood cells (RBCs) that make up 3 kg of the circulating blood. RBCs are potential reservoirs for epoxy fatty acids that regulate cardiovascular function. We studied 15 healthy persons and 15 ESRD patients undergoing regular hemodialysis treatments. We measured epoxides derived from CYP monooxygenase and metabolites derived from LOX/CYP ω/(ω-1)-hydroxylase pathways in RBCs by LC-MS/MS tandem mass spectrometry. Our data demonstrate that various CYP epoxides and LOX/CYP ω/(ω-1)-hydroxylase products are increased in RBCs of ESRD patients, compared to control subjects, including dihydroxyeicosatrienoic acids (DHETs), epoxyeicosatetraenoic acids (EEQs), dihydroxydocosapentaenoic acids (DiHDPAs), and hydroxyeicosatetraenoic acids (HETEs). Hemodialysis treatment did not affect the majority of those metabolites. Nevertheless, we detected more pronounced changes in free metabolite levels in RBCs after dialysis, as compared with the total RBC compartment. These findings indicate that free RBC eicosanoids should be considered more dynamic or vulnerable in CKD.
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Affiliation(s)
- Benjamin Gollasch
- Experimental and Clinical Research Center (ECRC)A Joint Institution Between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular MedicineBerlin‐BuchGermany
- HELIOS Klinikum Berlin‐BuchBerlinGermany
| | - Guanlin Wu
- Experimental and Clinical Research Center (ECRC)A Joint Institution Between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular MedicineBerlin‐BuchGermany
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz AssociationBerlinGermany
| | - Tong Liu
- Experimental and Clinical Research Center (ECRC)A Joint Institution Between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular MedicineBerlin‐BuchGermany
| | | | | | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC)A Joint Institution Between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular MedicineBerlin‐BuchGermany
- Nephrology/Intensive Care SectionCharité Campus VirchowBerlinGermany
- Department of Internal and Geriatric MedicineUniversity Medicine GreifswaldGreifswaldGermany
| | - Friedrich C. Luft
- Nephrology/Intensive Care SectionCharité Campus VirchowBerlinGermany
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9
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Gollasch B, Dogan I, Rothe M, Gollasch M, Luft FC. Maximal exercise and plasma cytochrome P450 and lipoxygenase mediators: a lipidomics study. Physiol Rep 2020; 7:e14165. [PMID: 31304687 PMCID: PMC6640589 DOI: 10.14814/phy2.14165] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/16/2019] [Accepted: 06/18/2019] [Indexed: 01/15/2023] Open
Abstract
Epoxides derived from arachidonic acid (AA) are released during exercise and may contribute to vasodilation. However, exercise may also affect circulating levels of other epoxides derived from cytochromes P450 (CYP) monooxygenase and lipoxygenase (LOX) pathways, many of whose exhibit cardiovascular activity in vitro. The effects of exercise on their levels have not been documented. We tested the hypothesis that acute, maximal exercise would influence the plasma concentrations of these vasoactive substances. We measured plasma CYP and LOX mediators derived from both the n − 3 and n − 6 fatty acid (FA) classes in healthy volunteers before, during and after short‐term exhaustive exercise. Lipid mediators were profiled by means of LC–MS/MS tandem mass spectrometry. A maximal Bruce treadmill test was performed to voluntary exhaustion. Exhaustive exercise increased the circulating levels of epoxyoctadecenoic (12,13‐EpOME), dihydroxyeicosatrienoic (5,6‐DHET), dihydroxyeicosatetraenoic acids (5,6‐DiHETE, 17,18‐DiHETE), but had no effect on the majority of CYP and LOX metabolites. Although our calculations of diol/epoxide ratios revealed preferred hydrolysis of epoxyeicosatrienoic acids (EEQs) into their diols (DiHETEs), this hydrolysis was resistant to maximal exercise. Our study is the first documentation that bioactive endogenous n − 3 and n − 6 CYP lipid mediators are released by short‐term exhaustive exercise in humans. In particular, the CYP epoxy‐metabolite status, 12,13‐EpOME/DiHOME, 5,6‐EET/DHET, 5,6‐EEQ/DiHETE and 17,18‐EEQ/DiHETE may contribute to the cardiovascular response during maximal exercise.
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Affiliation(s)
- Benjamin Gollasch
- Experimental and Clinical Research Center (ECRC), a Joint Institution between the Charité University Medicine, Max Delbrück Center (MDC) for Molecular Medicine, Berlin-Buch, Germany.,HELIOS Klinikum Berlin-Buch, Berlin, Germany
| | | | | | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC), a Joint Institution between the Charité University Medicine, Max Delbrück Center (MDC) for Molecular Medicine, Berlin-Buch, Germany
| | - Friedrich C Luft
- Experimental and Clinical Research Center (ECRC), a Joint Institution between the Charité University Medicine, Max Delbrück Center (MDC) for Molecular Medicine, Berlin-Buch, Germany.,Max-Delbrück Center (MDC) for Molecular Medicine in the Helmholtz Association, Berlin, Germany
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10
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Gollasch B, Wu G, Dogan I, Rothe M, Gollasch M, Luft FC. Effects of hemodialysis on plasma oxylipins. Physiol Rep 2020; 8:e14447. [PMID: 32562348 PMCID: PMC7305238 DOI: 10.14814/phy2.14447] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/04/2020] [Accepted: 04/24/2020] [Indexed: 12/17/2022] Open
Abstract
Chronic kidney disease (CKD) is an important risk factor for cardiovascular and all‐cause mortality. Survival rates among end‐stage renal disease (ESRD) hemodialysis patients are poor and most deaths are related to cardiovascular disease. Oxylipins constitute a family of oxygenated natural products, formed from fatty acid by pathways involving at least one step of dioxygen‐dependent oxidation. They are derived from polyunsaturated fatty acids (PUFAs) by cyclooxygenase (COX) enzymes, by lipoxygenases (LOX) enzymes, or by cytochrome P450 epoxygenase. Oxylipins have physiological significance and some could be of regulatory importance. The effects of decreased renal function and dialysis treatment on oxylipin metabolism are unknown. We studied 15 healthy persons and 15 CKD patients undergoing regular hemodialysis treatments and measured oxylipins (HPLC‐MS lipidomics) derived from cytochrome P450 (CYP) monooxygenase and lipoxygenase (LOX)/CYP ω/(ω‐1)‐hydroxylase pathways in circulating blood. We found that all four subclasses of CYP epoxy metabolites were increased after the dialysis treatment. Rather than resulting from altered soluble epoxide hydrolase (sEH) activity, the oxylipins were released and accumulated in the circulation. Furthermore, hemodialysis did not change the majority of LOX/CYP ω/(ω‐1)‐hydroxylase metabolites. Our data support the idea that oxylipin profiles discriminate ESRD patients from normal controls and are influenced by renal replacement therapies.
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Affiliation(s)
- Benjamin Gollasch
- Experimental and Clinical Research Center (ECRC), a joint institution between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular Medicine, Berlin-Buch, Germany.,HELIOS Klinikum Berlin-Buch, Berlin, Germany
| | - Guanlin Wu
- Experimental and Clinical Research Center (ECRC), a joint institution between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular Medicine, Berlin-Buch, Germany.,Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany
| | | | | | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC), a joint institution between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular Medicine, Berlin-Buch, Germany.,Department of Geriatrics, University of Greifswald, University District Hospital Wolgast, Greifswald, Germany
| | - Friedrich C Luft
- Experimental and Clinical Research Center (ECRC), a joint institution between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular Medicine, Berlin-Buch, Germany
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11
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Lu T, Chai Q, Jiao G, Wang XL, Sun X, Furuseth JD, Stulak JM, Daly RC, Greason KL, Cha YM, Lee HC. Downregulation of BK channel function and protein expression in coronary arteriolar smooth muscle cells of type 2 diabetic patients. Cardiovasc Res 2020; 115:145-153. [PMID: 29850792 DOI: 10.1093/cvr/cvy137] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 05/22/2018] [Indexed: 12/20/2022] Open
Abstract
Aims Type 2 diabetes (T2D) is strongly associated with cardiovascular morbidity and mortality in patients. Vascular large conductance Ca2+-activated potassium (BK) channels, composed of four pore-forming α subunits (BK-α), and four regulatory β1 subunits (BK-β1), are densely expressed in coronary arterial smooth muscle cells (SMCs) and play an important role in regulating vascular tone and myocardial perfusion. However, the role of BK channels in coronary microvascular dysfunction of human subjects with diabetes is unclear. In this study, we examined BK channel function and protein expression, and BK channel-mediated vasodilation in freshly isolated coronary arterioles from T2D patients. Methods and results Atrial tissues were obtained from 16 patients with T2D and 25 matched non-diabetic subjects during cardiopulmonary bypass procedure. Microvessel videomicroscopy and immunoblot analysis were performed in freshly dissected coronary arterioles and inside-out single BK channel currents was recorded in enzymatically isolated coronary arteriolar SMCs. We found that BK channel sensitivity to physiological Ca2+ concentration and voltage was downregulated in the coronary arteriolar SMCs of diabetic patients, compared with non-diabetic controls. BK channel kinetics analysis revealed that there was significant shortening of the mean open time and prolongation of the mean closed time in diabetic patients, resulting in a remarkable reduction of the channel open probability. Functional studies showed that BK channel activation by dehydrosoyasaponin-1 was diminished and that BK channel-mediated vasodilation in response to shear stress was impaired in diabetic coronary arterioles. Immunoblot experiments confirmed that the protein expressions of BK-α and BK-β1 subunits were significantly downregulated, but the ratio of BK-α/BK-β1 was unchanged in the coronary arterioles of T2D patients. Conclusions Our results demonstrated for the first time that BK channel function and BK channel-mediated vasodilation were abnormal in the coronary microvasculature of diabetic patients, due to decreased protein expression and altered intrinsic properties of BK channels.
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Affiliation(s)
- Tong Lu
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - Qiang Chai
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA.,Department of Physiology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, 89 Jingshi Road, Jinan, Shandong, PR China
| | - Guoqing Jiao
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA.,Department of Cardiovascular Surgery, Wuxi People's Hospital Affiliated to Nanjing Medical University, 299 Qingyang Road, Wuxi, Jiangsu, PR China
| | - Xiao-Li Wang
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - Xiaojing Sun
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - Jonathan D Furuseth
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - John M Stulak
- Department of Cardiovascular Surgery, Mayo Clinic, 200 First Street, SW., Rochester, Minnesota, USA
| | - Richard C Daly
- Department of Cardiovascular Surgery, Mayo Clinic, 200 First Street, SW., Rochester, Minnesota, USA
| | - Kevin L Greason
- Department of Cardiovascular Surgery, Mayo Clinic, 200 First Street, SW., Rochester, Minnesota, USA
| | - Yong-Mei Cha
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
| | - Hon-Chi Lee
- Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW., Rochester, Minnesota, USA
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12
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Grimes D, Watson D. Epoxyeicosatrienoic acids protect pancreatic beta cells against pro-inflammatory cytokine toxicity. Biochem Biophys Res Commun 2019; 520:231-236. [PMID: 31590920 DOI: 10.1016/j.bbrc.2019.09.124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 09/27/2019] [Indexed: 11/19/2022]
Abstract
Pro-inflammatory cytokines contribute to pancreatic beta cell death in the pathogenesis of type 1 diabetes mellitus (DM). Cytochrome P450-derived epoxyeicosatrienoic acids (EETs), produced by selective epoxidation of arachidonic acid, display anti-inflammatory activity in numerous disease models, in part through inhibition of NFκB activity. No studies have directly assessed their roles in cellular models of pancreatic beta cell death and therefore we aimed to investigate the cytoprotective effects of the EET isomers 8(9)-, 11(12)- and 14(15)-EET and their corresponding vicinal diols (dihydroxyeicosatrienoic acids, DHETs) in a model of pro-inflammatory cytokine-toxicity using the rat pancreatic beta cell line BRIN-BD11. Co-treatment of cells with a cocktail of pro-inflammatory cytokines (IL-1β, IFNγ and TNFα) caused a marked increase in caspase activation and a reduction in cell viability, effects attenuated by inclusion of each EET; this was also associated with a reduction in cytokine-induced NFκB activation and nitrite accumulation. Surprisingly, of the DHET derivatives of EETs, 8(9)-DHET conferred similar protective effects against cytokine-induced caspase activation. This data therefore highlights a novel role of EETs and a surprising activity of 8(9)-DHET in attenuating cytokine-toxicity in pancreatic beta cells.
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Affiliation(s)
- Daniel Grimes
- School of Life Sciences, Keele University, Staffordshire, UK
| | - David Watson
- School of Life Sciences, Keele University, Staffordshire, UK.
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13
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Gollasch B, Wu G, Dogan I, Rothe M, Gollasch M, Luft FC. Maximal exercise and erythrocyte epoxy fatty acids: a lipidomics study. Physiol Rep 2019; 7:e14275. [PMID: 31782268 PMCID: PMC6882955 DOI: 10.14814/phy2.14275] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 01/02/2023] Open
Abstract
Fatty acid (FA)-derived lipid products generated by cytochrome P450 (CYP), lipoxygenase (LOX), and cyclo-oxygenase (COX) influence cardiovascular function. However, plasma measurements invariably ignore 40% of the blood specimen, namely the erythrocytes. These red blood cells (RBCs) represent a cell mass of about 3 kg. RBCs are a potential reservoir for epoxy fatty acids, which on release could regulate vascular capacity. We tested the hypothesis that maximal physical activity would influence the epoxy fatty acid status in RBCs. We used a standardized maximal treadmill exercise according to Bruce to ensure a robust hemodynamic and metabolic response. Central hemodynamic monitoring was performed using blood pressure and heart rate measurements and maximal workload was assessed in metabolic equivalents (METs). We used tandem mass spectrometry (LC-MS/MS) to measure epoxides derived from CYP monooxygenase, as well as metabolites derived from LOX, COX, and CYP hydroxylase pathways. Venous blood was obtained for RBC lipidomics. With the incremental exercise test, increases in the levels of various CYP epoxy-mediators in RBCs, including epoxyoctadecenoic acids (9,10-EpOME, 12,13-EpOME), epoxyeicosatrienoic acids (5,6-EET, 11,12-EET, 14,15-EET), and epoxydocosapentaenoic acids (16,17-EDP, 19,20-EDP) occurred, as heart rate, systolic blood pressure, and plasma lactate concentrations increased. Maximal (13.5 METs) exercise intensity had no effect on diols and various LOX, COX, and hydroxylase mediators. Our findings suggest that CYP epoxy-metabolites could contribute to the cardiovascular response to maximal exercise.
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Affiliation(s)
- Benjamin Gollasch
- Experimental and Clinical Research Center (ECRC), a joint institution between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular MedicineBerlin‐BuchGermany
- HELIOS Klinikum Berlin‐BuchBerlinGermany
| | - Guanlin Wu
- Experimental and Clinical Research Center (ECRC), a joint institution between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular MedicineBerlin‐BuchGermany
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz AssociationBerlinGermany
| | | | | | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC), a joint institution between the Charité University Medicine and Max Delbrück Center (MDC) for Molecular MedicineBerlin‐BuchGermany
- Nephrology/Intensive Care SectionCharité Campus VirchowBerlinGermany
| | - Friedrich C. Luft
- Nephrology/Intensive Care SectionCharité Campus VirchowBerlinGermany
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14
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Dopico AM, Bukiya AN, Jaggar JH. Calcium- and voltage-gated BK channels in vascular smooth muscle. Pflugers Arch 2018; 470:1271-1289. [PMID: 29748711 DOI: 10.1007/s00424-018-2151-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 04/27/2018] [Indexed: 02/04/2023]
Abstract
Ion channels in vascular smooth muscle regulate myogenic tone and vessel contractility. In particular, activation of calcium- and voltage-gated potassium channels of large conductance (BK channels) results in outward current that shifts the membrane potential toward more negative values, triggering a negative feed-back loop on depolarization-induced calcium influx and SM contraction. In this short review, we first present the molecular basis of vascular smooth muscle BK channels and the role of subunit composition and trafficking in the regulation of myogenic tone and vascular contractility. BK channel modulation by endogenous signaling molecules, and paracrine and endocrine mediators follows. Lastly, we describe the functional changes in smooth muscle BK channels that contribute to, or are triggered by, common physiological conditions and pathologies, including obesity, diabetes, and systemic hypertension.
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Affiliation(s)
- Alex M Dopico
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St., Memphis, TN, 38163, USA.
| | - Anna N Bukiya
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, 71 South Manassas St., Memphis, TN, 38163, USA
| | - Jonathan H Jaggar
- Department of Physiology, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, USA
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15
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Kato Y, Mukai Y, Rane A, Inotsume N, Toda T. Combined effect of telmisartan and fluvastatin on arachidonic acid metabolism in human liver microsomes. Xenobiotica 2017; 48:898-903. [PMID: 28933256 DOI: 10.1080/00498254.2017.1384079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
1. Epoxyeicosatrienoic acids (EETs), metabolites of arachidonic acid (AA) via cytochrome P450s, have a protective effect on the cardiovascular system involving vasodilation. We have previously demonstrated that telmisartan (TEL) inhibits EETs production from AA in vitro. 2. The objectives of the study were to examine the inhibitory effect of fluvastatin (FLU), an inhibitor of CYP2C9, and the combined effect of TEL and FLU on the production of EETs using human liver microsomes. The combined effect of TEL and FLU was evaluated using two methods, the fixed concentration method and the fixed ratio method. 3. FLU significantly reduced total eicosanoids (sum of EETs and their subsequent metabolites dihydroxyeicosatrienoic acids) production at > 0.25 µM. The results of the fixed concentration method indicated that the addition of the other inhibitor resulted in significant reduction of the production of total eicosanoids in a concentration-dependent manner. In the fixed ratio method, the combination of TEL and FLU over all concentration ratios tested did not produce a horizontal shift in the dose response curves. 4. Our results showing an additive combined effect of TEL and FLU on AA metabolism, suggest that concomitant treatment with TEL and FLU would theoretically affect the vascular tone mediated by EETs from AA.
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Affiliation(s)
- Yuka Kato
- a Division of Clinical Pharmacology, Hokkaido Pharmaceutical University School of Pharmacy , Sapporo , Japan and
| | - Yuji Mukai
- a Division of Clinical Pharmacology, Hokkaido Pharmaceutical University School of Pharmacy , Sapporo , Japan and
| | - Anders Rane
- b Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska University Hospital, Karolinska Institutet , Stockholm , Sweden
| | - Nobuo Inotsume
- a Division of Clinical Pharmacology, Hokkaido Pharmaceutical University School of Pharmacy , Sapporo , Japan and
| | - Takaki Toda
- a Division of Clinical Pharmacology, Hokkaido Pharmaceutical University School of Pharmacy , Sapporo , Japan and
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16
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Dai H, Wang M, Patel PN, Kalogeris T, Liu Y, Durante W, Korthuis RJ. Preconditioning with the BK Ca channel activator NS-1619 prevents ischemia-reperfusion-induced inflammation and mucosal barrier dysfunction: roles for ROS and heme oxygenase-1. Am J Physiol Heart Circ Physiol 2017; 313:H988-H999. [PMID: 28822969 DOI: 10.1152/ajpheart.00620.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 07/25/2017] [Accepted: 08/07/2017] [Indexed: 12/12/2022]
Abstract
Activation of large-conductance Ca2+-activated K+ (BKCa) channels evokes cell survival programs that mitigate intestinal ischemia and reperfusion (I/R) inflammation and injury 24 h later. The goal of the present study was to determine the roles of reactive oxygen species (ROS) and heme oxygenase (HO)-1 in delayed acquisition of tolerance to I/R induced by pretreatment with the BKCa channel opener NS-1619. Superior mesentery arteries were occluded for 45 min followed by reperfusion for 70 min in wild-type (WT) or HO-1-null (HO-1-/-) mice that were pretreated with NS-1619 or saline vehicle 24 h earlier. Intravital microscopy was used to quantify the numbers of rolling and adherent leukocytes. Mucosal permeability, tumor necrosis factor-α (TNF-α) levels, and HO-1 activity and expression in jejunum were also determined. I/R induced leukocyte rolling and adhesion, increased intestinal TNF-α levels, and enhanced mucosal permeability in WT mice, effects that were largely abolished by pretreatment with NS-1619. The anti-inflammatory and mucosal permeability-sparing effects of NS-1619 were prevented by coincident treatment with the HO-1 inhibitor tin protoporphyrin-IX or a cell-permeant SOD mimetic, Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP), in WT mice. NS-1619 also increased jejunal HO-1 activity in WT animals, an effect that was attenuated by treatment with the BKCa channel antagonist paxilline or MnTBAP. I/R also increased postischemic leukocyte rolling and adhesion and intestinal TNF-α levels in HO-1-/- mice to levels comparable to those noted in WT animals. However, NS-1619 was ineffective in preventing these effects in HO-1-deficient mice. In summary, our data indicate that NS-1619 induces the development of an anti-inflammatory phenotype and mitigates postischemic mucosal barrier disruption in the small intestine by a mechanism that may involve ROS-dependent HO-1 activity.NEW & NOTEWORTHY Antecedent treatment with the large-conductance Ca2+-activated K+ channel opener NS-1619 24 h before ischemia-reperfusion limits postischemic tissue injury by an oxidant-dependent mechanism. The present study shows that NS-1619-induced oxidant production prevents ischemia-reperfusion-induced inflammation and mucosal barrier disruption in the small intestine by provoking increases in heme oxygenase-1 activity.
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Affiliation(s)
- Hongyan Dai
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Meifang Wang
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Parag N Patel
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Theodore Kalogeris
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Yajun Liu
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - William Durante
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Ronald J Korthuis
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
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17
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Elinder F, Liin SI. Actions and Mechanisms of Polyunsaturated Fatty Acids on Voltage-Gated Ion Channels. Front Physiol 2017; 8:43. [PMID: 28220076 PMCID: PMC5292575 DOI: 10.3389/fphys.2017.00043] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 01/16/2017] [Indexed: 01/29/2023] Open
Abstract
Polyunsaturated fatty acids (PUFAs) act on most ion channels, thereby having significant physiological and pharmacological effects. In this review we summarize data from numerous PUFAs on voltage-gated ion channels containing one or several voltage-sensor domains, such as voltage-gated sodium (NaV), potassium (KV), calcium (CaV), and proton (HV) channels, as well as calcium-activated potassium (KCa), and transient receptor potential (TRP) channels. Some effects of fatty acids appear to be channel specific, whereas others seem to be more general. Common features for the fatty acids to act on the ion channels are at least two double bonds in cis geometry and a charged carboxyl group. In total we identify and label five different sites for the PUFAs. PUFA site 1: The intracellular cavity. Binding of PUFA reduces the current, sometimes as a time-dependent block, inducing an apparent inactivation. PUFA site 2: The extracellular entrance to the pore. Binding leads to a block of the channel. PUFA site 3: The intracellular gate. Binding to this site can bend the gate open and increase the current. PUFA site 4: The interface between the extracellular leaflet of the lipid bilayer and the voltage-sensor domain. Binding to this site leads to an opening of the channel via an electrostatic attraction between the negatively charged PUFA and the positively charged voltage sensor. PUFA site 5: The interface between the extracellular leaflet of the lipid bilayer and the pore domain. Binding to this site affects slow inactivation. This mapping of functional PUFA sites can form the basis for physiological and pharmacological modifications of voltage-gated ion channels.
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Affiliation(s)
- Fredrik Elinder
- Department of Clinical and Experimental Medicine, Linköping University Linköping, Sweden
| | - Sara I Liin
- Department of Clinical and Experimental Medicine, Linköping University Linköping, Sweden
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18
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Titz B, Luettich K, Leroy P, Boue S, Vuillaume G, Vihervaara T, Ekroos K, Martin F, Peitsch MC, Hoeng J. Alterations in Serum Polyunsaturated Fatty Acids and Eicosanoids in Patients with Mild to Moderate Chronic Obstructive Pulmonary Disease (COPD). Int J Mol Sci 2016; 17:E1583. [PMID: 27657052 PMCID: PMC5037848 DOI: 10.3390/ijms17091583] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 09/06/2016] [Accepted: 09/13/2016] [Indexed: 01/08/2023] Open
Abstract
Smoking is a major risk factor for several diseases including chronic obstructive pulmonary disease (COPD). To better understand the systemic effects of cigarette smoke exposure and mild to moderate COPD-and to support future biomarker development-we profiled the serum lipidomes of healthy smokers, smokers with mild to moderate COPD (GOLD stages 1 and 2), former smokers, and never-smokers (n = 40 per group) (ClinicalTrials.gov registration: NCT01780298). Serum lipidome profiling was conducted with untargeted and targeted mass spectrometry-based lipidomics. Guided by weighted lipid co-expression network analysis, we identified three main trends comparing smokers, especially those with COPD, with non-smokers: a general increase in glycero(phospho)lipids, including triglycerols; changes in fatty acid desaturation (decrease in ω-3 polyunsaturated fatty acids, and an increase in monounsaturated fatty acids); and an imbalance in eicosanoids (increase in 11,12- and 14,15-DHETs (dihydroxyeicosatrienoic acids), and a decrease in 9- and 13-HODEs (hydroxyoctadecadienoic acids)). The lipidome profiles supported classification of study subjects as smokers or non-smokers, but were not sufficient to distinguish between smokers with and without COPD. Overall, our study yielded further insights into the complex interplay between smoke exposure, lung disease, and systemic alterations in serum lipid profiles.
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Affiliation(s)
- Bjoern Titz
- Philip Morris International Research and Development, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
| | - Karsta Luettich
- Philip Morris International Research and Development, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
| | - Patrice Leroy
- Philip Morris International Research and Development, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
| | - Stephanie Boue
- Philip Morris International Research and Development, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
| | - Gregory Vuillaume
- Philip Morris International Research and Development, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
| | | | - Kim Ekroos
- Zora Biosciences Oy, 02150 Espoo, Finland.
| | - Florian Martin
- Philip Morris International Research and Development, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
| | - Manuel C Peitsch
- Philip Morris International Research and Development, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
| | - Julia Hoeng
- Philip Morris International Research and Development, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
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Krishnamoorthy-Natarajan G, Koide M. BK Channels in the Vascular System. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 128:401-38. [PMID: 27238270 DOI: 10.1016/bs.irn.2016.03.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Autoregulation of blood flow is essential for the preservation of organ function to ensure continuous supply of oxygen and essential nutrients and removal of metabolic waste. This is achieved by controlling the diameter of muscular arteries and arterioles that exhibit a myogenic response to changes in arterial blood pressure, nerve activity and tissue metabolism. Large-conductance voltage and Ca(2+)-dependent K(+) channels (BK channels), expressed exclusively in smooth muscle cells (SMCs) in the vascular wall of healthy arteries, play a critical role in regulating the myogenic response. Activation of BK channels by intracellular, local, and transient ryanodine receptor-mediated "Ca(2+) sparks," provides a hyperpolarizing influence on the SMC membrane potential thereby decreasing the activity of voltage-dependent Ca(2+) channels and limiting Ca(2+) influx to promote SMC relaxation and vasodilation. The BK channel α subunit, a large tetrameric protein with each monomer consisting of seven-transmembrane domains, a long intracellular C-terminal tail and an extracellular N-terminus, associates with the β1 and γ subunits in vascular SMCs. The BK channel is regulated by factors originating within the SMC or from the endothelium, perivascular nerves and circulating blood, that significantly alter channel gating properties, Ca(2+) sensitivity and expression of the α and/or β1 subunit. The BK channel thus serves as a central receiving dock that relays the effects of the changes in several such concomitant autocrine and paracrine factors and influences cardiovascular health. This chapter describes the primary mechanism of regulation of myogenic response by BK channels and the alterations to this mechanism wrought by different vasoactive mediators.
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Affiliation(s)
| | - M Koide
- University of Vermont, Burlington, VT, United States
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20
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Gabbs M, Leng S, Devassy JG, Monirujjaman M, Aukema HM. Advances in Our Understanding of Oxylipins Derived from Dietary PUFAs. Adv Nutr 2015; 6:513-40. [PMID: 26374175 PMCID: PMC4561827 DOI: 10.3945/an.114.007732] [Citation(s) in RCA: 472] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Oxylipins formed from polyunsaturated fatty acids (PUFAs) are the main mediators of PUFA effects in the body. They are formed via cyclooxygenase, lipoxygenase, and cytochrome P450 pathways, resulting in the formation of prostaglandins, thromboxanes, mono-, di-, and tri-hydroxy fatty acids (FAs), epoxy FAs, lipoxins, eoxins, hepoxilins, resolvins, protectins (also called neuroprotectins in the brain), and maresins. In addition to the well-known eicosanoids derived from arachidonic acid, recent developments in lipidomic methodologies have raised awareness of and interest in the large number of oxylipins formed from other PUFAs, including those from the essential FAs and the longer-chain n-3 (ω-3) PUFAs. Oxylipins have essential roles in normal physiology and function, but can also have detrimental effects. Compared with the oxylipins derived from n-3 PUFAs, oxylipins from n-6 PUFAs generally have greater activity and more inflammatory, vasoconstrictory, and proliferative effects, although there are notable exceptions. Because PUFA composition does not necessarily reflect oxylipin composition, comprehensive analysis of the oxylipin profile is necessary to understand the overall physiologic effects of PUFAs mediated through their oxylipins. These analyses should include oxylipins derived from linoleic and α-linolenic acids, because these largely unexplored bioactive oxylipins constitute more than one-half of oxylipins present in tissues. Because collated information on oxylipins formed from different PUFAs is currently unavailable, this review provides a detailed compilation of the main oxylipins formed from PUFAs and describes their functions. Much remains to be elucidated in this emerging field, including the discovery of more oxylipins, and the understanding of the differing biological potencies, kinetics, and isomer-specific activities of these novel PUFA metabolites.
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Affiliation(s)
| | | | | | | | - Harold M Aukema
- Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada; and Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, Canada
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21
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Role of phosphatase activity of soluble epoxide hydrolase in regulating simvastatin-activated endothelial nitric oxide synthase. Sci Rep 2015; 5:13524. [PMID: 26304753 PMCID: PMC4548251 DOI: 10.1038/srep13524] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 07/28/2015] [Indexed: 01/10/2023] Open
Abstract
Soluble epoxide hydrolase (sEH) has C-terminal epoxide hydrolase and N-terminal lipid phosphatase activity. Its hydrolase activity is associated with endothelial nitric oxide synthase (eNOS) dysfunction. However, little is known about the role of sEH phosphatase in regulating eNOS activity. Simvastatin, a clinical lipid-lowering drug, also has a pleiotropic effect on eNOS activation. However, whether sEH phosphatase is involved in simvastatin-activated eNOS activity remains elusive. We investigated the role of sEH phosphatase activity in simvastatin-mediated activation of eNOS in endothelial cells (ECs). Simvastain increased the phosphatase activity of sEH, which was diminished by pharmacological inhibitors of sEH phosphatase. In addition, pharmacological inhibition of sEH phosphatase or overexpressing the inactive phosphatase domain of sEH enhanced simvastatin-induced NO bioavailability, tube formation and phosphorylation of eNOS, Akt, and AMP-activated protein kinase (AMPK). In contrast, overexpressing the phosphatase domain of sEH limited the simvastatin-increased NO biosynthesis and eNOS phosphorylation at Ser1179. Simvastatin evoked epidermal growth factor receptor–c-Src–increased Tyr phosphorylation of sEH and formation of an sEH–Akt–AMPK–eNOS complex, which was abolished by the c-Src kinase inhibitor PP1 or c-Src dominant-negative mutant K298M. These findings suggest that sEH phosphatase activity negatively regulates simvastatin-activated eNOS by impeding the Akt–AMPK–eNOS signaling cascade.
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22
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Chai Q, Lu T, Wang XL, Lee HC. Hydrogen sulfide impairs shear stress-induced vasodilation in mouse coronary arteries. Pflugers Arch 2015; 467:329-40. [PMID: 24793048 DOI: 10.1007/s00424-014-1526-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Revised: 04/15/2014] [Accepted: 04/16/2014] [Indexed: 01/01/2023]
Abstract
Hydrogen sulfide has emerged as an important endothelium-dependent vasodilator, but its role in shear stress-mediated dilation of coronary arteries is unclear. We examined the role of H2S on shear stress-mediated dilation of isolated mouse coronary arteries. In these vessels, Na2S produced concentration-dependent dilation, which was significantly inhibited by iberiotoxin and by 4-aminopyridine. In addition, BK and Kv currents in mouse coronary smooth muscle cells were directly activated by Na2S, suggesting that H2S produced vasodilation through BK and Kv channel activation. Using a pressure servo controller system, freshly isolated mouse coronary arteries were subjected to physiological levels of shear stress (1 to 25 dynes/cm(2)) and produced graded dilatory responses, but such effects were diminished in the presence of 100 μM Na2S. Pre-incubation with the cystathionine γ-lyase inhibitor, D,L-propargylglycine (PPG), resulted in a paradoxical augmentation of shear stress-mediated vasodilation. However, in the presence of L-NAME or in coronary arteries from eNOS knockout mice, PPG inhibited shear stress-mediated vasodilation, suggesting an interaction between NO and H2S signaling. Na2S inhibited eNOS activity in cultured mouse aortic endothelial cells and reduced the level of phospho-eNOS(serine 1177). These results suggest that both NO and H2S are important shear stress-mediated vasodilators in mouse coronary arteries but there is a complex interaction between these two signaling pathways that results in paradoxical vasoconstrictive effects of H2S through inhibition of NO generation.
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Affiliation(s)
- Qiang Chai
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN, 55905, USA,
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Dopico AM, Bukiya AN. Lipid regulation of BK channel function. Front Physiol 2014; 5:312. [PMID: 25202277 PMCID: PMC4141547 DOI: 10.3389/fphys.2014.00312] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/31/2014] [Indexed: 01/11/2023] Open
Abstract
This mini-review focuses on lipid modulation of BK (MaxiK, BKCa) current by a direct interaction between lipid and the BK subunits and/or their immediate lipid environment. Direct lipid-BK protein interactions have been proposed for fatty and epoxyeicosatrienoic acids, phosphoinositides and cholesterol, evidence for such action being less clear for other lipids. BK α (slo1) subunits are sufficient to support current perturbation by fatty and epoxyeicosatrienoic acids, glycerophospholipids and cholesterol, while distinct BK β subunits seem necessary for current modulation by most steroids. Subunit domains or amino acids that participate in lipid action have been identified in a few cases: hslo1 Y318, cerebral artery smooth muscle (cbv1) R334,K335,K336, cbv1 seven cytosolic CRAC domains, slo1 STREX and β1 T169,L172,L173 for docosahexaenoic acid, PIP2, cholesterol, sulfatides, and cholane steroids, respectively. Whether these protein motifs directly bind lipids or rather transmit the energy of lipid binding to other areas and trigger protein conformation change remains unresolved. The impact of direct lipid-BK interaction on physiology is briefly discussed.
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Affiliation(s)
- Alex M Dopico
- Department of Pharmacology, The University of Tennessee Health Science Center Memphis, TN, USA
| | - Anna N Bukiya
- Department of Pharmacology, The University of Tennessee Health Science Center Memphis, TN, USA
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Spector AA, Kim HY. Cytochrome P450 epoxygenase pathway of polyunsaturated fatty acid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:356-65. [PMID: 25093613 DOI: 10.1016/j.bbalip.2014.07.020] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/22/2014] [Accepted: 07/25/2014] [Indexed: 12/19/2022]
Abstract
Polyunsaturated fatty acids (PUFA) are oxidized by cytochrome P450 epoxygenases to PUFA epoxides which function as potent lipid mediators. The major metabolic pathways of PUFA epoxides are incorporation into phospholipids and hydrolysis to the corresponding PUFA diols by soluble epoxide hydrolase. Inhibitors of soluble epoxide hydrolase stabilize PUFA epoxides and potentiate their functional effects. The epoxyeicosatrienoic acids (EETs) synthesized from arachidonic acid produce vasodilation, stimulate angiogenesis, have anti-inflammatory actions, and protect the heart against ischemia-reperfusion injury. EETs produce these functional effects by activating receptor-mediated signaling pathways and ion channels. The epoxyeicosatetraenoic acids synthesized from eicosapentaenoic acid and epoxydocosapentaenoic acids synthesized from docosahexaenoic acid are potent inhibitors of cardiac arrhythmias. Epoxydocosapentaenoic acids also inhibit angiogenesis, decrease inflammatory and neuropathic pain, and reduce tumor metastasis. These findings indicate that a number of the beneficial functions of PUFA may be due to their conversion to PUFA epoxides. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".
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Affiliation(s)
- Arthur A Spector
- Laboratory of Molecular Signaling, National Institute of Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.
| | - Hee-Yong Kim
- Laboratory of Molecular Signaling, National Institute of Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
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Yi F, Wang H, Chai Q, Wang X, Shen WK, Willis MS, Lee HC, Lu T. Regulation of large conductance Ca2+-activated K+ (BK) channel β1 subunit expression by muscle RING finger protein 1 in diabetic vessels. J Biol Chem 2014; 289:10853-10864. [PMID: 24570002 DOI: 10.1074/jbc.m113.520940] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The large conductance Ca(2+)-activated K(+) (BK) channel, expressed abundantly in vascular smooth muscle cells (SMCs), is a key determinant of vascular tone. BK channel activity is tightly regulated by its accessory β1 subunit (BK-β1). However, BK channel function is impaired in diabetic vessels by increased ubiquitin/proteasome-dependent BK-β1 protein degradation. Muscle RING finger protein 1 (MuRF1), a muscle-specific ubiquitin ligase, is implicated in many cardiac and skeletal muscle diseases. However, the role of MuRF1 in the regulation of vascular BK channel and coronary function has not been examined. In this study, we hypothesized that MuRF1 participated in BK-β1 proteolysis, leading to the down-regulation of BK channel activation and impaired coronary function in diabetes. Combining patch clamp and molecular biological approaches, we found that MuRF1 expression was enhanced, accompanied by reduced BK-β1 expression, in high glucose-cultured human coronary SMCs and in diabetic vessels. Knockdown of MuRF1 by siRNA in cultured human SMCs attenuated BK-β1 ubiquitination and increased BK-β1 expression, whereas adenoviral expression of MuRF1 in mouse coronary arteries reduced BK-β1 expression and diminished BK channel-mediated vasodilation. Physical interaction between the N terminus of BK-β1 and the coiled-coil domain of MuRF1 was demonstrated by pulldown assay. Moreover, MuRF1 expression was regulated by NF-κB. Most importantly, pharmacological inhibition of proteasome and NF-κB activities preserved BK-β1 expression and BK-channel-mediated coronary vasodilation in diabetic mice. Hence, our results provide the first evidence that the up-regulation of NF-κB-dependent MuRF1 expression is a novel mechanism that leads to BK channelopathy and vasculopathy in diabetes.
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Affiliation(s)
- Fu Yi
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905; Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xian 710032, China
| | - Huan Wang
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Qiang Chai
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Xiaoli Wang
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Win-Kuang Shen
- Department of Internal Medicine, Mayo Clinic, Scottsdale, Arizona 85259
| | - Monte S Willis
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Hon-Chi Lee
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Tong Lu
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905.
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Aspromonte N, Monitillo F, Puzzovivo A, Valle R, Caldarola P, Iacoviello M. Modulation of cardiac cytochrome P450 in patients with heart failure. Expert Opin Drug Metab Toxicol 2014; 10:327-39. [DOI: 10.1517/17425255.2014.872240] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Kundu S, Roome T, Bhattacharjee A, Carnevale KA, Yakubenko VP, Zhang R, Hwang SH, Hammock BD, Cathcart MK. Metabolic products of soluble epoxide hydrolase are essential for monocyte chemotaxis to MCP-1 in vitro and in vivo. J Lipid Res 2012; 54:436-47. [PMID: 23160182 DOI: 10.1194/jlr.m031914] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monocyte chemoattractant protein-1 (MCP-1)-induced monocyte chemotaxis is a major event in inflammatory disease. Our prior studies have demonstrated that MCP-1-dependent chemotaxis requires release of arachidonic acid (AA) by activated cytosolic phospholipase A(2) (cPLA(2)). Here we investigated the involvement of AA metabolites in chemotaxis. Neither cyclooxygenase nor lipoxygenase pathways were required, whereas pharmacologic inhibitors of both the cytochrome-P450 (CYP) and the soluble epoxide hydrolase (sEH) pathways blocked monocyte chemotaxis to MCP-1. To verify specificity, we demonstrated that the CYP and sEH products epoxyeiscosatrienoic acids (EETs) and dihydroxyeicosatrienoic acids (DHETs), respectively, restored chemotaxis in the presence of the inhibitors, indicating that sEH-derived products are essential for MCP-1-driven chemotaxis. Importantly, DHETs also rescued chemotaxis in cPLA(2)-deficient monocytes and monocytes with blocked Erk1/2 activity, because Erk controls cPLA(2) activation. The in vitro findings regarding the involvement of CYP/sEH pathways were further validated in vivo using two complementary approaches measuring MCP-1-dependent chemotaxis in mice. These observations reveal the importance of sEH in MCP-1-regulated monocyte chemotaxis and may explain the observed therapeutic value of sEH inhibitors in treatment of inflammatory diseases, cardiovascular diseases, pain, and even carcinogenesis. Their effectiveness, often attributed to increasing EET levels, is probably influenced by the impairment of DHET formation and inhibition of chemotaxis.
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Affiliation(s)
- Suman Kundu
- Department of Cell Biology, and Research Core Services, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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Farr H, David T. Models of neurovascular coupling via potassium and EET signalling. J Theor Biol 2011; 286:13-23. [PMID: 21781976 DOI: 10.1016/j.jtbi.2011.07.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 07/08/2011] [Accepted: 07/11/2011] [Indexed: 11/30/2022]
Abstract
Functional hyperemia is an important metabolic autoregulation mechanism by which increased neuronal activity is matched by a rapid and regional increase in blood supply. This mechanism is facilitated by a process known as "neurovascular coupling"--the orchestrated communication system involving neurons, astrocytes and arterioles. Important steps in this process are the production of EETs in the astrocyte and the release of potassium, via two potassium channels (BK and KIR), into the perivascular space. We provide a model which successfully accounts for several observations seen in experiment. The model is capable of simulating the approximate 15% arteriolar dilation caused by a 60-s neuronal activation (modelled as a release of potassium and glutamate into the synaptic cleft). This model also successfully emulates the paradoxical experimental finding that vasoconstriction follows vasodilation when the astrocytic calcium concentration (or perivascular potassium concentration) is increased further. We suggest that the interaction of the changing smooth muscle cell membrane potential and the changing potassium-dependent resting potential of the KIR channel are responsible for this effect. Finally, we demonstrate that a well-controlled mechanism of potassium buffering is potentially important for successful neurovascular coupling.
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Affiliation(s)
- Hannah Farr
- Centre for Bioengineering, University of Canterbury, New Zealand; Van der Veer Institute for Parkinson's and Brain Research, Christchurch, New Zealand
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Regulation of forskolin-induced cAMP production by cytochrome P450 epoxygenase metabolites of arachidonic acid in HEK293 cells. Cell Biol Toxicol 2011; 27:321-32. [PMID: 21519968 DOI: 10.1007/s10565-011-9190-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 04/07/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Cytochrome P450 epoxygenases metabolize arachidonic acid to epoxyeicosatrienoic acids (EETs), which in turn are converted to dihydroxyeicosatrienoic acids (DHETs) by soluble epoxide hydrolase (sEH). EETs are known to modulate a number of vascular and renal functions, but the exact signaling mechanism(s) of these EET-mediated effects remains unknown. PURPOSE The purpose of this study is to investigate the role of EETs and DHETs in regulating cyclic adenosine monophosphate (cAMP) production via adenylyl cyclase in a human embryonic kidney cell line (HEK293). METHOD HEK293 cells were treated with vehicle, forskolin, epinephrine, 11,12-EET, 11,12-DHET, as well as potential pathway and G-protein inhibitors to assess changes in cAMP production. RESULTS Co-administering 11,12-EET with forskolin effectively eliminated the increased cAMP levels observed in cells treated with forskolin alone. The inhibitory effect of EETs on forskolin-mediated cAMP production was abolished when cells were treated with a sEH inhibitor (tAUCB). 11,12-DHET also negated the effects of forskolin, suggesting that the inhibitory effect observed in EET-treated cells could be attributed to the downstream metabolites, DHETs. In contrast, inhibition of phosphodiesterase IV (PDE4) with rolipram eliminated the effects of EETs or DHETs, and inhibition of Gαi with pertussis toxin also resulted in enhanced cAMP production. CONCLUSION Our data suggest that DHETs regulate cAMP production via PDE4 and Gαi protein. Moreover, they provide novel evidence as to how EET-mediated signaling may alter G-protein coupling in HEK293 cells.
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Wang RX, Chai Q, Lu T, Lee HC. Activation of vascular BK channels by docosahexaenoic acid is dependent on cytochrome P450 epoxygenase activity. Cardiovasc Res 2010; 91:9-15. [PMID: 21187320 DOI: 10.1093/cvr/cvq412] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
AIMS n-3 Polyunsaturated fatty acids (PUFAs) are known to protect the cardiovascular system and improve blood pressure control. These important dietary constituents are converted into bioactive metabolites, but their role in regulation of the cardiovascular system is unclear. In particular, the functions of the cytochrome P450 (CYP) metabolites of n-3 PUFAs remain virtually unexplored. In this study, we examined the effects of docosahexaenoic acid (DHA) on the regulation of large-conductance calcium-activated potassium (BK) channel activities in coronary arterial smooth muscle cells. METHODS AND RESULTS Using whole-cell patch-clamp techniques, we found that DHA is a potent activator of BK currents in rat coronary arterial smooth muscle cells with an EC(50) of 0.23 ± 0.03 µM. This effect was abolished by pre-incubation with the CYP epoxygenase inhibitor, SKF525A (10 µM). The effects of DHA on the BK channels were reproduced by 16,17-epoxydocosapentaenoic acid (16,17-EpDPE) with an EC(50) of 19.7 ± 2.8 nM. The physiological role of the CYP metabolites of DHA was confirmed by measuring DHA-mediated vasodilatation in isolated rat coronary arteries. DHA dilated pressurized isolated coronary arteries in a dose-dependent manner, and the DHA effects were abolished after pre-treatment with SKF525A (10 µM) or with iberiotoxin (100 nM). In addition, 16,17-EpDPE directly produced coronary vasodilatation that was iberiotoxin sensitive. CONCLUSION These results suggest that DHA-mediated vasodilatation is mediated through CYP epoxygenase metabolites by activation of vascular BK channels.
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Affiliation(s)
- Ru-xing Wang
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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31
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Wang RX, Chai Q, Lu T, Lee HC. Activation of vascular BK channels by docosahexaenoic acid is dependent on cytochrome P450 epoxygenase activity. Cardiovasc Res 2010; 90:344-52. [PMID: 21187320 DOI: 10.1093/cvr/cvq411] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIMS n-3 Polyunsaturated fatty acids (PUFAs) are known to protect the cardiovascular system and improve blood pressure control. These important dietary constituents are converted into bioactive metabolites, but their role in regulation of the cardiovascular system is unclear. In particular, the functions of the cytochrome P450 (CYP) metabolites of n-3 PUFAs remain virtually unexplored. In this study, we examined the effects of docosahexaenoic acid (DHA) on the regulation of large-conductance calcium-activated potassium (BK) channel activities in coronary arterial smooth muscle cells. METHODS AND RESULTS Using whole-cell patch-clamp techniques, we found that DHA is a potent activator of BK currents in rat coronary arterial smooth muscle cells with an EC(50) of 0.23 ± 0.03 µM. This effect was abolished by pre-incubation with the CYP epoxygenase inhibitor, SKF525A (10 µM). The effects of DHA on the BK channels were reproduced by 16,17-epoxydocosapentaenoic acid (16,17-EpDPE) with an EC(50) of 19.7 ± 2.8 nM. The physiological role of the CYP metabolites of DHA was confirmed by measuring DHA-mediated vasodilatation in isolated rat coronary arteries. DHA dilated pressurized isolated coronary arteries in a dose-dependent manner, and the DHA effects were abolished after pre-treatment with SKF525A (10 µM) or with iberiotoxin (100 nM). In addition, 16,17-EpDPE directly produced coronary vasodilatation that was iberiotoxin sensitive. CONCLUSION These results suggest that DHA-mediated vasodilatation is mediated through CYP epoxygenase metabolites by activation of vascular BK channels.
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Affiliation(s)
- Ru-xing Wang
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Townsley MI, Morisseau C, Hammock B, King JA. Impact of epoxyeicosatrienoic acids in lung ischemia-reperfusion injury. Microcirculation 2010; 17:137-46. [PMID: 20163540 DOI: 10.1111/j.1549-8719.2009.00013.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Epoxyeicosatrienoic acids (EETs) are protective in both myocardial and brain ischemia, variously attributed to activation of K(ATP) channels or blockade of adhesion molecule upregulation. In this study, we tested whether EETs would be protective in lung ischemia-reperfusion injury. METHODS The filtration coefficient (K(f)), a measure of endothelial permeability, and expression of the adhesion molecules vascular cell adhesion molecule (VCAM) and intercellular adhesion molecule (ICAM) were measured after 45 minutes ischemia and 30 minutes reperfusion in isolated rat lungs. RESULTS K(f) increased significantly after ischemia-reperfusion alone vs time controls, an effect dependent upon extracellular Ca(2+) although not on the EET-regulated channel TRPV4. Inhibition of endogenous EET degradation or administration of exogenous 11,12- or 14,-15-EET at reperfusion significantly limited the permeability response to ischemia-reperfusion. The beneficial effect of 11,12-EET was not prevented by blockade of K(ATP) channels nor by blockade of TRPV4. Finally, 11,12-EET-dependent alteration in adhesion molecules expression is unlikely to explain its beneficial effect, since the expression of the adhesion molecules VCAM and ICAM in lung after ischemia-reperfusion was similar to that in controls. CONCLUSION EETs are beneficial in the setting of lung ischemia-reperfusion, when administered at reperfusion. However, further study will be needed to elucidate the mechanism of action.
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Affiliation(s)
- Mary I Townsley
- Department of Physiology, Center for Lung Biology, University of South Alabama, Mobile, AL 36688, USA.
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Dick GM, Tune JD. Role of potassium channels in coronary vasodilation. Exp Biol Med (Maywood) 2010; 235:10-22. [DOI: 10.1258/ebm.2009.009201] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
K+ channels in coronary arterial smooth muscle cells (CASMC) determine the resting membrane potential ( Em) and serve as targets of endogenous and therapeutic vasodilators. Em in CASMC is in the voltage range for activation of L-type Ca2+ channels; therefore, when K+ channel activity changes, Ca2+ influx and arterial tone change. This is why both Ca2+ channel blockers and K+ channel openers have such profound effects on coronary blood flow; the former directly inhibits Ca2+ influx through L-type Ca2+ channels, while the latter indirectly inhibits Ca2+ influx by hyperpolarizing Em and reducing Ca2+ channel activity. K+ channels in CASMC play important roles in vasodilation to endothelial, ischemic and metabolic stimuli. The purpose of this article is to review the types of K+ channels expressed in CASMC, discuss the regulation of their activity by physiological mechanisms and examine impairments related to cardiovascular disease.
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Affiliation(s)
- Gregory M Dick
- Department of Exercise Physiology and Center for Cardiovascular & Respiratory Sciences, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Johnathan D Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Miller TM, Donnelly MK, Crago EA, Roman DM, Sherwood PR, Horowitz MB, Poloyac SM. Rapid, simultaneous quantitation of mono and dioxygenated metabolites of arachidonic acid in human CSF and rat brain. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:3991-4000. [PMID: 19892608 DOI: 10.1016/j.jchromb.2009.10.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 08/31/2009] [Accepted: 10/07/2009] [Indexed: 11/16/2022]
Abstract
Currently, there are few biomarkers to predict the risk of symptomatic cerebral vasospasm (SV) in subarachnoid hemorrhage (SAH) patients. Mono and dioxygenated arachidonic acid metabolites, involved in the pathogenesis of ischemic injury, may serve as indicators of SV. This study developed a quantitative UPLC-MS/MS method to simultaneously measure hydroxyeicosatetraenoic acid (HETE), dihydroxyeicosatrienoic acid (DiHETrE), and epoxyeicosatrienoic acid (EET) metabolites of arachidonic acid in cerebrospinal fluid (CSF) samples of SAH patients. Additionally, we determined the recovery of these metabolites from polyvinylchloride (PVC) bags used for CSF collection. Linear calibration curves ranging from 0.208 to 33.3 ng/ml were validated. The inter-day and intra-day variance was less than 15% at most concentrations with extraction efficiency greater than 73%. The matrix did not affect the reproducibility and reliability of the assay. In CSF samples, peak concentrations of 8,9-DiHETrE, 20-HETE, 15-HETE, and 12-HETE ranged from 0.293 to 24.9 ng/ml. In rat brain cortical tissue samples, concentrations of 20-, 15-, 12-HETE, 8,9-EET, and 14,15-, 11,12-DiHETrE ranged from 0.57 to 23.99 pmol/g wet tissue. In rat cortical microsomal incubates, all 10 metabolites were measured with formation rates ranging from 0.03 to 7.77 pmol/mg/min. Furthermore, 12-HETE and EET metabolites were significantly altered by contact with PVC bags at all time points evaluated. These data demonstrate that the simultaneous measurement of these compounds in human CSF and rat brain can be achieved with a UPLC-MS/MS system and that this method is necessary for evaluation of these metabolites as potential quantitative biomarkers in future clinical trials.
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Affiliation(s)
- Tricia M Miller
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Buczynski MW, Dumlao DS, Dennis EA. Thematic Review Series: Proteomics. An integrated omics analysis of eicosanoid biology. J Lipid Res 2009; 50:1015-38. [PMID: 19244215 PMCID: PMC2681385 DOI: 10.1194/jlr.r900004-jlr200] [Citation(s) in RCA: 400] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 02/23/2009] [Indexed: 11/20/2022] Open
Abstract
Eicosanoids have been implicated in a vast number of devastating inflammatory conditions, including arthritis, atherosclerosis, pain, and cancer. Currently, over a hundred different eicosanoids have been identified, with many having potent bioactive signaling capacity. These lipid metabolites are synthesized de novo by at least 50 unique enzymes, many of which have been cloned and characterized. Due to the extensive characterization of eicosanoid biosynthetic pathways, this field provides a unique framework for integrating genomics, proteomics, and metabolomics toward the investigation of disease pathology. To facilitate a concerted systems biology approach, this review outlines the proteins implicated in eicosanoid biosynthesis and signaling in human, mouse, and rat. Applications of the extensive genomic and lipidomic research to date illustrate the questions in eicosanoid signaling that could be uniquely addressed by a thorough analysis of the entire eicosanoid proteome.
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Affiliation(s)
| | | | - Edward A. Dennis
- Department of Chemistry and Biochemistry, Department of Pharmacology, and School of Medicine, University of California, San Diego, La Jolla, CA 92093
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Grgic I, Kaistha BP, Hoyer J, Köhler R. Endothelial Ca+-activated K+ channels in normal and impaired EDHF-dilator responses--relevance to cardiovascular pathologies and drug discovery. Br J Pharmacol 2009; 157:509-26. [PMID: 19302590 DOI: 10.1111/j.1476-5381.2009.00132.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The arterial endothelium critically contributes to blood pressure control by releasing vasodilating autacoids such as nitric oxide, prostacyclin and a third factor or pathway termed 'endothelium-derived hyperpolarizing factor' (EDHF). The nature of EDHF and EDHF-signalling pathways is not fully understood yet. However, endothelial hyperpolarization mediated by the Ca(2+)-activated K(+) channels (K(Ca)) has been suggested to play a critical role in initializing EDHF-dilator responses in conduit and resistance-sized arteries of many species including humans. Endothelial K(Ca) currents are mediated by the two K(Ca) subtypes, intermediate-conductance K(Ca) (KCa3.1) (also known as, a.k.a. IK(Ca)) and small-conductance K(Ca) type 3 (KCa2.3) (a.k.a. SK(Ca)). In this review, we summarize current knowledge about endothelial KCa3.1 and KCa2.3 channels, their molecular and pharmacological properties and their specific roles in endothelial function and, particularly, in the EDHF-dilator response. In addition we focus on recent experimental evidences derived from KCa3.1- and/or KCa2.3-deficient mice that exhibit severe defects in EDHF signalling and elevated blood pressures, thus highlighting the importance of the KCa3.1/KCa2.3-EDHF-dilator system for blood pressure control. Moreover, we outline differential and overlapping roles of KCa3.1 and KCa2.3 for EDHF signalling as well as for nitric oxide synthesis and discuss recent evidence for a heterogeneous (sub) cellular distribution of KCa3.1 (at endothelial projections towards the smooth muscle) and KCa2.3 (at inter-endothelial borders and caveolae), which may explain their distinct roles for endothelial function. Finally, we summarize the interrelations of altered KCa3.1/KCa2.3 and EDHF system impairments with cardiovascular disease states such as hypertension, diabetes, dyslipidemia and atherosclerosis and discuss the therapeutic potential of KCa3.1/KCa2.3 openers as novel types of blood pressure-lowering drugs.
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Affiliation(s)
- Ivica Grgic
- Department of Internal Medicine-Nephrology, Philipps-University, Marburg, Germany
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Abstract
Cytochrome P450 (CYP) epoxygenases convert arachidonic acid to four epoxyeicosatrienoic acid (EET) regioisomers, 5,6-, 8,9-, 11,12-, and 14,15-EET, that function as autacrine and paracrine mediators. EETs produce vascular relaxation by activating smooth muscle large-conductance Ca2+-activated K+ channels (BKCa). In addition, they have anti-inflammatory effects on blood vessels and in the kidney, promote angiogenesis, and protect ischemic myocardium and brain. CYP epoxygenases also convert eicosapentaenoic acid to vasoactive epoxy-derivatives, and endocannabinoids containing 11,12- and 14,15-EET are formed. Many EET actions appear to be initiated by EET binding to a membrane receptor that activates ion channels and intracellular signal transduction pathways. However, EETs also are taken up by cells, are incorporated into phospholipids, and bind to cytosolic proteins and nuclear receptors, suggesting that some functions may occur through direct interaction of the EET with intracellular effector systems. Soluble epoxide hydrolase (sEH) converts EETs to dihydroxyeicosatrienoic acids (DHETs). Because this attenuates many of the functional effects of EETs, sEH inhibition is being evaluated as a mechanism for increasing and prolonging the beneficial actions of EETs.
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Affiliation(s)
- Arthur A Spector
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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38
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Impaired Ca2+-dependent activation of large-conductance Ca2+-activated K+ channels in the coronary artery smooth muscle cells of Zucker Diabetic Fatty rats. Biophys J 2008; 95:5165-77. [PMID: 18790848 DOI: 10.1529/biophysj.108.138339] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The large-conductance Ca(2+)-activated K(+) (BK) channels play an important role in the regulation of cellular excitability in response to changes in intracellular metabolic state and Ca(2+) homeostasis. In vascular smooth muscle, BK channels are key determinants of vasoreactivity and vital-organ perfusion. Vascular BK channel functions are impaired in diabetes mellitus, but the mechanisms underlying such changes have not been examined in detail. We examined and compared the activities and kinetics of BK channels in coronary arterial smooth muscle cells from Lean control and Zucker Diabetic Fatty (ZDF) rats, using single-channel recording techniques. We found that BK channels in ZDF rats have impaired Ca(2+) sensitivity, including an increased free Ca(2+) concentration at half-maximal effect on channel activation, a reduced steepness of Ca(2+) dose-dependent curve, altered Ca(2+)-dependent gating properties with decreased maximal open probability, and a shortened mean open-time and prolonged mean closed-time durations. In addition, the BK channel beta-subunit-mediated activation by dehydrosoyasaponin-1 (DHS-1) was lost in cells from ZDF rats. Immunoblotting analysis confirmed a 2.1-fold decrease in BK channel beta(1)-subunit expression in ZDF rats, compared with that of Lean rats. These abnormalities in BK channel gating lead to an increase in the energy barrier for channel activation, and may contribute to the development of vascular dysfunction and complications in type 2 diabetes mellitus.
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39
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He T, Lu T, d'Uscio LV, Lam CF, Lee HC, Katusic ZS. Angiogenic function of prostacyclin biosynthesis in human endothelial progenitor cells. Circ Res 2008; 103:80-8. [PMID: 18511850 DOI: 10.1161/circresaha.108.176057] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The role of prostaglandin production in the control of regenerative function of endothelial progenitor cells (EPCs) has not been studied. We hypothesized that activation of cyclooxygenase (COX) enzymatic activity and the subsequent production of prostacyclin (PGI(2)) is an important mechanism responsible for the regenerative function of EPCs. In the present study, we detected high levels of COX-1 protein expression and PGI(2) biosynthesis in human EPCs outgrown from blood mononuclear cells. Expression of COX-2 protein was almost undetectable under basal conditions but significantly elevated after treatment with tumor necrosis factor-alpha. Condition medium derived from EPCs hyperpolarized human coronary artery smooth muscle cells, similar to the effect of the PGI(2) analog iloprost. The proliferation and in vitro tube formation by EPCs were inhibited by the COX inhibitor indomethacin or by genetic inactivation of COX-1 or PGI(2) synthase with small interfering (si)RNA. Impaired tube formation and cell proliferation induced by inactivation of COX-1 were rescued by the treatment with iloprost or the selective peroxisome proliferator-activated receptor (PPAR)delta agonist GW501516 but not by the selective PGI(2) receptor agonist cicaprost. Downregulation of PPARdelta by siRNA also reduced angiogenic capacity of EPCs. Iloprost failed to reverse PPARdelta siRNA-induced impairment of angiogenesis. Furthermore, transfection of PGI(2) synthase siRNA, COX-1 siRNA, or PPARdelta siRNA into EPCs decreased the capillary formation in vivo after transplantation of human EPCs into the nude mice. These results suggest that activation of COX-1/PGI(2)/PPARdelta pathway is an important mechanism underlying proangiogenic function of EPCs.
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Affiliation(s)
- Tongrong He
- Department of Anesthesiology and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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40
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Labitzke EM, Diani-Moore S, Rifkind AB. Mitochondrial P450-dependent arachidonic acid metabolism by TCDD-induced hepatic CYP1A5; conversion of EETs to DHETs by mitochondrial soluble epoxide hydrolase. Arch Biochem Biophys 2007; 468:70-81. [PMID: 17959137 PMCID: PMC2868376 DOI: 10.1016/j.abb.2007.08.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 08/06/2007] [Accepted: 08/13/2007] [Indexed: 01/18/2023]
Abstract
Several P450 enzymes localized in the endoplasmic reticulum and thought to be involved primarily in xenobiotic metabolism, including mouse and rat CYP1A1 and mouse CYP1A2, have also been found to translocate to mitochondria. We report here that the environmental toxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces enzymatically active CYP1A4/1A5, the avian orthologs of mammalian CYP1A1/1A2, in chick embryo liver mitochondria as well as in microsomes. P450 proteins and activity levels (CYP1A4-dependent 7-ethoxyresorufin-O-deethylase and CYP1A5-dependent arachidonic acid epoxygenation) in mitochondria were 23-40% of those in microsomes. DHET formation by mitochondria was twice that of microsomes and was attributable to a mitochondrial soluble epoxide hydrolase as confirmed by Western blotting with antiEPHX2, conversion by mitochondria of pure 11,12 and 14,15-EET to the corresponding DHETs and inhibition of DHET formation by the soluble epoxide hydrolase inhibitor, 12(-3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA). TCDD also suppressed formation of mitochondrial and microsomal 20-HETE. The findings newly identify mitochondria as a site of P450-dependent arachidonic acid metabolism and as a potential target for TCDD effects. They also demonstrate that mitochondria contain soluble epoxide hydrolase and underscore a role for CYP1A in endobiotic metabolism.
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Affiliation(s)
- Erin M Labitzke
- Weill Medical College of Cornell University, Department of Pharmacology, 1300 York Avenue, Room LC-401, New York, NY 10021, USA
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41
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Calderone V, Martelli A, Testai L, Martinotti E, Breschi MC. Functional contribution of the endothelial component to the vasorelaxing effect of resveratrol and NS 1619, activators of the large-conductance calcium-activated potassium channels. Naunyn Schmiedebergs Arch Pharmacol 2007; 375:73-80. [PMID: 17203288 DOI: 10.1007/s00210-006-0129-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Accepted: 11/29/2006] [Indexed: 11/26/2022]
Abstract
Large-conductance calcium-activated potassium channels (BK) of smooth muscle play a role in the relevant modulation of vascular tone, due to their calcium- and voltage-dependent mechanisms of activation. A potential role of endothelial BK channels has also been suggested by approaches on endothelial cell cultures. However, no functional study, aimed at evaluating the contribution of endothelial BK channels to the effect of BK-openers, has been reported. Resveratrol and NS 1619, BK-openers, have been tested on endothelium-intact and -denuded aortic rings. Furthermore, the effects of high depolarisation of potassium channel blockers TEA (Tetraethylammonium), 4-AP ( 4-Aminopyridine) and IbTX (Iberiotoxin) and of inhibitors of NO-pathway (L-NAME and ODQ) have been evaluated. The presence of endothelium increased the vasorelaxing potency of BK-openers. This potentiation was eliminated by L-NAME and ODQ. TEA, 4-AP, IbTX and high depolarisation had modest or no antagonist influence on resveratrol in endothelium-denuded aortic rings. The effects of NS 1619 on endothelium-denuded aortic rings were not affected by IbTX, and were modestly antagonised by TEA, 4-AP and high depolarisation. In intact endothelium vessels, TEA, IbTX and 4-AP antagonised the vasorelaxing effect of the two BK-activators. A BK-mediated release of endothelial NO seems a very important factor, determining a strong influence on vasodilator profile of BK-openers. Therefore, an eventual therapy with a BK-opener could promote a series of cardiovascular impacts not confined to the only direct vasorelaxing effects, but also due to a significant contribution of endothelial NO.
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Affiliation(s)
- Vincenzo Calderone
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126, Pisa, Italy.
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42
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Jiang JG, Chen RJ, Xiao B, Yang S, Wang JN, Wang Y, Cowart LA, Xiao X, Wang DW, Xia Y. Regulation of endothelial nitric-oxide synthase activity through phosphorylation in response to epoxyeicosatrienoic acids. Prostaglandins Other Lipid Mediat 2007; 82:162-74. [PMID: 17164144 DOI: 10.1016/j.prostaglandins.2006.08.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 08/25/2006] [Accepted: 08/29/2006] [Indexed: 11/29/2022]
Abstract
Endothelial nitric oxide synthase (eNOS) is a key enzyme in NO-mediated cardiovascular homeostasis and its activity is modulated by a variety of hormonal and mechanical stimuli via phosphorylation modification. Our previous study has demonstrated that epoxyeicosatrienoic acids (EETs), the cytochrome P450 (CYP)-dependent metabolites of arachidonic acid, could robustly up-regulate eNOS expression. However, the molecular mechanism underlying the effects of EETs on eNOS remains elusive. Particularly, whether and how EETs affect eNOS phosphorylation is unknown. In the present study, we investigated the effects of EETs on eNOS phosphorylation with cultured bovine aortic endothelial cells (BAECs). BAECs were either treated with exogenous EETs or infected with recombinant adeno-associated virus (rAAV) carrying CYP2C11-CYPOR, CYP102 F87V mutant and CYP2J2, respectively, to increase endogenous EETs. Both addition of EETs and CYP epoxygenase transfection markedly increased eNOS phosphorylation at its Ser1179 and Thr497 residues. Inhibition of phosphatidylinositol 3-kinase (PI3K) with LY294002 prevented EETs-induced increases of eNOS-Ser(P)1179 but had no effect on the phosphorylation status of Thr497. However, inhibitors of protein kinase B (Akt), mitogen-activated protein kinase (MAPK) and MAPK kinase could block phosphorylation of eNOS at both sites. Inhibition of these kinases also attenuated the up-regulation of eNOS expression by EETs. Finally, administration of viral CYP epoxygenases expression vectors into rats enhanced eNOS phosphorylation and function in vivo. Thus, in addition to up-regulating eNOS expression, EETs also augment eNOS function by enhancing eNOS phosphorylation. EETs-induced up-regulation of eNOS phosphorylation and expression appears to involve in both PI3K/Akt and MAPK pathways.
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Affiliation(s)
- Jian Gang Jiang
- The Institute of Hypertension and Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430030, China
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43
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Elbekai RH, El-Kadi AOS. Cytochrome P450 enzymes: Central players in cardiovascular health and disease. Pharmacol Ther 2006; 112:564-87. [PMID: 16824612 DOI: 10.1016/j.pharmthera.2005.05.011] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Accepted: 05/17/2005] [Indexed: 02/02/2023]
Abstract
Cardiovascular disease (CVD) is a human health crisis that remains the leading cause of death worldwide. The cytochrome P450 (CYP) class of enzymes are key metabolizers of both xenobiotics and endobiotics. Many CYP enzyme families have been identified in the heart, endothelium and smooth muscle of blood vessels. Furthermore, mounting evidence points to the role of endogenous CYP metabolites, such as epoxyeicosatrienoic acids (EETs), hydroxyeicosatetraenoic acids (HETEs), prostacyclin (PGI(2)), aldosterone, and sex hormones, in the maintenance of cardiovascular health. Emerging science and the development of genetic screening have provided us with information on the differences in CYP expression among populations and groups of individuals. With this information, a link between CYP expression and activity and CVD, such as hypertension, coronary artery disease (CAD), myocardial infarction, heart failure, stroke, and cardiomyopathy and arrhythmias, has been established. In fact many currently used therapeutic modalities in CVD owe their therapeutic efficacy to their effect on CYP metabolites. Thus, the evidence for the involvement of CYP in CVD is numerous. Concentrating on treatment modalities that target the CYP pathway makes ethical sense for the affected individuals and decreases the socioeconomic burden of this disease. However, more research is needed to allow the integration of this information into a clinical setting.
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Affiliation(s)
- Reem H Elbekai
- Faculty of Pharmacy and Pharmaceutical Sciences, 3126 Dentistry/Pharmacy Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2N8
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44
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Spector AA, Norris AW. Action of epoxyeicosatrienoic acids on cellular function. Am J Physiol Cell Physiol 2006; 292:C996-1012. [PMID: 16987999 DOI: 10.1152/ajpcell.00402.2006] [Citation(s) in RCA: 352] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Epoxyeicosatrienoic acids (EETs), which function primarily as autocrine and paracrine mediators in the cardiovascular and renal systems, are synthesized from arachidonic acid by cytochrome P-450 epoxygenases. They activate smooth muscle large-conductance Ca(2+)-activated K(+) channels, producing hyperpolarization and vasorelaxation. EETs also have anti-inflammatory effects in the vasculature and kidney, stimulate angiogenesis, and have mitogenic effects in the kidney. Many of the functional effects of EETs occur through activation of signal transduction pathways and modulation of gene expression, events probably initiated by binding to a putative cell surface EET receptor. However, EETs are rapidly taken up by cells and are incorporated into and released from phospholipids, suggesting that some functional effects may occur through a direct interaction between the EET and an intracellular effector system. In this regard, EETs and several of their metabolites activate peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma, suggesting that some functional effects may result from PPAR activation. EETs are metabolized primarily by conversion to dihydroxyeicosatrienoic acids (DHETs), a reaction catalyzed by soluble epoxide hydrolase (sEH). Many potentially beneficial actions of EETs are attenuated upon conversion to DHETs, which do not appear to be essential under routine conditions. Therefore, sEH is considered a potential therapeutic target for enhancing the beneficial functions of EETs.
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Affiliation(s)
- Arthur A Spector
- Dept. of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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45
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Lu T, He T, Katusic ZS, Lee HC. Molecular Mechanisms Mediating Inhibition of Human Large Conductance Ca
2+
-Activated K
+
Channels by High Glucose. Circ Res 2006; 99:607-16. [PMID: 16931797 DOI: 10.1161/01.res.0000243147.41792.93] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Diabetic vascular dysfunction is associated with an increase in reactive oxygen species (ROS). In this study, we hypothesized that hyperglycemia-induced ROS generation would impair the function of large conductance Ca
2+
-activated K
+
(BK) channels, which are major determinants in vasorelaxation. We found that when cultured in high glucose (HG) (22 mmol/L), HEK293 cells showed a reduction in expressed hSlo current densities, as well as slowed activation and deactivation kinetics. When human coronary smooth muscle cells were cultured in HG, similar findings were observed for the BK currents. HG enhanced superoxide dismutase and suppressed catalase (CAT) expression in HEK293 cells, leading to a significant increase in intracellular ROS. The effects of HG were mimicked by hydrogen peroxide (H
2
O
2
), and hSlo functions were restored by CAT gene transfer. Peroxynitrite inhibited hSlo current density but did not change channel kinetics. The hSloC911A mutant was insensitive to the effects of HG and H
2
O
2
. Hence, imbalance of antioxidant enzymes plays a critical role in ROS generation in HG, impairing hSlo functions through H
2
O
2
-dependent oxidation at cysteine 911. This may represent an important fundamental mechanism that contributes to the impairment of vasodilation in diabetes.
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Affiliation(s)
- Tong Lu
- Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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46
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Oz M. Receptor-independent actions of cannabinoids on cell membranes: Focus on endocannabinoids. Pharmacol Ther 2006; 111:114-44. [PMID: 16584786 DOI: 10.1016/j.pharmthera.2005.09.009] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Accepted: 09/30/2005] [Indexed: 01/08/2023]
Abstract
Cannabinoids are a structurally diverse group of mostly lipophilic molecules that bind to cannabinoid receptors. In fact, endogenous cannabinoids (endocannabinoids) are a class of signaling lipids consisting of amides and esters of long-chain polyunsaturated fatty acids. They are synthesized from lipid precursors in plasma membranes via Ca(2+) or G-protein-dependent processes and exhibit cannabinoid-like actions by binding to cannabinoid receptors. However, endocannabinoids can produce effects that are not mediated by these receptors. In pharmacologically relevant concentrations, endocannabinoids modulate the functional properties of voltage-gated ion channels including Ca(2+) channels, Na(+) channels, various types of K(+) channels, and ligand-gated ion channels such as serotonin type 3, nicotinic acetylcholine, and glycine receptors. In addition, modulatory effects of endocannabinoids on other ion-transporting membrane proteins such as transient potential receptor-class channels, gap junctions and transporters for neurotransmitters have also been demonstrated. Furthermore, functional properties of G-protein-coupled receptors for different types of neurotransmitters and neuropeptides are altered by direct actions of endocannabinoids. Although the mechanisms of these effects are currently not clear, it is likely that these direct actions of endocannabinoids are due to their lipophilic structures. These findings indicate that additional molecular targets for endocannabinoids exist and that these targets may represent novel sites for cannabinoids to alter either the excitability of the neurons or the response of the neuronal systems. This review focuses on the results of recent studies indicating that beyond their receptor-mediated effects, endocannabinoids alter the functions of ion channels and other integral membrane proteins directly.
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Affiliation(s)
- Murat Oz
- National Institute on Drug Abuse, NIH/DHHS, Intramural Research Program, Cellular Neurobiology Branch, 5500 Nathan Shock Drive, Baltimore MD, 21224, USA.
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47
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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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48
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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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49
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Sade H, Muraki K, Ohya S, Hatano N, Imaizumi Y. Activation of large-conductance, Ca2+-activated K+channels by cannabinoids. Am J Physiol Cell Physiol 2006; 290:C77-86. [PMID: 16107501 DOI: 10.1152/ajpcell.00482.2004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We have examined the effects of the cannabinoid anandamide (AEA) and its stable analog, methanandamide (methAEA), on large-conductance, Ca2+-activated K+(BK) channels using human embryonic kidney (HEK)-293 cells, in which the α-subunit of the BK channel (BK-α), both α- and β1-subunits (BK-αβ1), or both α- and β4-subunits (BK-αβ4) were heterologously expressed. In a whole cell voltage-clamp configuration, each cannabinoid activated BK-αβ1within a similar concentration range. Because methAEA could potentiate BK-α, BK-αβ1, and BK-αβ4with similar efficacy, the β-subunits may not be involved at the site of action for cannabinoids. Under cell-attached patch-clamp conditions, application of methAEA to the bathing solution increased BK channel activity; however, methAEA did not alter channel activity in the excised inside-out patch mode even when ATP was present on the cytoplasmic side of the membrane. Application of methAEA to HEK-BK-α and HEK-BK-αβ1did not change intracellular Ca2+concentration. Moreover, methAEA-induced potentiation of BK channel currents was not affected by pretreatment with a CB1antagonist (AM251), modulators of G proteins (cholera and pertussis toxins) or by application of a selective CB2agonist (JWH133). Inhibitors of CaM, PKG, and MAPKs (W7, KT5823, and PD-98059) did not affect the potentiation. Application of methAEA to mouse aortic myocytes significantly increased BK channel currents. This study provides the first direct evidence that unknown factors in the cytoplasm mediate the ability of endogenous cannabinoids to activate BK channel currents. Cannabinoids may be hyperpolarizing factors in cells, such as arterial myocytes, in which BK channels are highly expressed.
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Affiliation(s)
- Hiroko Sade
- Dept. of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City Univ., 3-1 Tanabedori, Mizuhoku, Nagoya 467-8603, Japan
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Vriens J, Owsianik G, Fisslthaler B, Suzuki M, Janssens A, Voets T, Morisseau C, Hammock BD, Fleming I, Busse R, Nilius B. Modulation of the Ca2 permeable cation channel TRPV4 by cytochrome P450 epoxygenases in vascular endothelium. Circ Res 2005; 97:908-15. [PMID: 16179585 DOI: 10.1161/01.res.0000187474.47805.30] [Citation(s) in RCA: 291] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
TRPV4 is a broadly expressed Ca2+-permeable cation channel in the vanilloid subfamily of transient receptor potential channels. TRPV4 gates in response to a large variety of stimuli, including cell swelling, warm temperatures, the synthetic phorbol ester 4alpha-phorbol 12,13-didecanoate (4alpha-PDD), and the endogenous lipid arachidonic acid (AA). Activation by cell swelling and AA requires cytochrome P450 (CYP) epoxygenase activity to convert AA to epoxyeicosatrienoic acids (EETs) such as 5,6-EET, 8,9-EET, which both act as direct TRPV4 agonists. To evaluate the role of TRPV4 and its modulation by the CYP pathway in vascular endothelial cells, we performed Ca2+ imaging and patch-clamp measurements on mouse aortic endothelial cells (MAECs) isolated from wild-type and TRPV4(-/-) mice. All TRPV4-activating stimuli induced robust Ca2+ responses in wild-type MAECs but not in MAECs isolated from TRPV4(-/-) mice. Upregulation of CYP2C expression by preincubation with nifedipine enhanced the responses to AA and cell swelling in wild-type MAECs, whereas responses to other stimuli remained unaffected. Conversely, inhibition of CYP2C9 activity with sulfaphenazole abolished the responses to AA and hypotonic solution (HTS). Moreover, suppression of EET hydrolysis using 1-adamantyl-3-cyclo-hexylurea or indomethacin, inhibitors of soluble epoxide hydrolases (sEHs), and cyclooxygenases, respectively, enhanced the TRPV4-dependent responses to AA, HTS, and EETs but not those to 4alpha-PDD or heat. Together, our data establish that CYP-derived EETs modulate the activity of TRPV4 channels in endothelial cells and shows the unraveling of novel modulatory pathways via CYP2C modulation and sEH inhibition.
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Affiliation(s)
- J Vriens
- Department of Physiology, Campus Gasthuisberg, KU Leuven, Belgium
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