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Barenco-Marins TS, Seara FAC, Ponte CG, Nascimento JHM. Pulmonary Circulation Under Pressure: Pathophysiological and Therapeutic Implications of BK Channel. Cardiovasc Drugs Ther 2023:10.1007/s10557-023-07503-7. [PMID: 37624526 DOI: 10.1007/s10557-023-07503-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/10/2023] [Indexed: 08/26/2023]
Abstract
The large-conductance Ca2+-activated K+ (BK) channel is widely expressed in the pulmonary blood vessels and plays a significant role in regulating pulmonary vascular tonus. It opens under membrane depolarization, increased intracellular Ca+2 concentration, and chronic hypoxia, resulting in massive K+ efflux, membrane hyperpolarization, decreased L-type Ca+2 channel opening, and smooth muscle relaxation. Several reports have demonstrated an association between BK channel dysfunction and pulmonary hypertension (PH) development. Decreased BK channel subunit expression and impaired regulation by paracrine hormones result in decreased BK channel opening, increased pulmonary vascular resistance, and pulmonary arterial pressure being the cornerstone of PH. The resulting right ventricular pressure overload ultimately leads to ventricular remodeling and failure. Therefore, it is unsurprising that the BK channel has arisen as a potential target for treating PH. Recently, a series of selective, synthetic BK channel agonists have proven effective in attenuating the pathophysiological progression of PH without adverse effects in animal models.
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Affiliation(s)
- Thais S Barenco-Marins
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Programa de Pós-Graduação Em Cardiologia, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Fernando A C Seara
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
- Instituto de Ciências Biológicas E da Saúde, Universidade Federal Rural Do Rio de Janeiro, Seropédica, RJ, Brazil.
- Programa de Pós-Graduação Multicêntrico Em Ciências Fisiológicas, Sociedade Brasileira de Fisiologia, São Paulo, Brazil.
| | - Cristiano G Ponte
- Instituto Federal de Educação, Ciências e Tecnologia do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Jose H M Nascimento
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Programa de Pós-Graduação Em Cardiologia, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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2
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Yang Q, Hori M. Characterization of Contractile Machinery of Vascular Smooth Muscles in Hypertension. Life (Basel) 2021; 11:life11070702. [PMID: 34357074 PMCID: PMC8304034 DOI: 10.3390/life11070702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 12/12/2022] Open
Abstract
Hypertension is a key risk factor for cardiovascular disease and it is a growing public health problem worldwide. The pathophysiological mechanisms of vascular smooth muscle (VSM) contraction contribute to the development of hypertension. Calcium (Ca2+)-dependent and -independent signaling mechanisms regulate the balance of the myosin light chain kinase and myosin light chain phosphatase to induce myosin phosphorylation, which activates VSM contraction to control blood pressure (BP). Here, we discuss the mechanism of the contractile machinery in VSM, especially RhoA/Rho kinase and PKC/CPI-17 of Ca2+ sensitization pathway in hypertension. The two signaling pathways affect BP in physiological and pathophysiological conditions and are highlighted in pulmonary, pregnancy, and salt-sensitive hypertension.
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Affiliation(s)
- Qunhui Yang
- Correspondence: ; Tel.: +81-3-5841-7940; Fax: +81-3-5841-8183
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The Novel Inodilator ORM-3819 Relaxes Isolated Porcine Coronary Arteries: Role of Voltage-Gated Potassium Channel Activation. J Cardiovasc Pharmacol 2020; 74:218-224. [PMID: 31356552 DOI: 10.1097/fjc.0000000000000700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Relaxation and changes in the transmembrane potential of vascular smooth muscle induced by ORM-3819, a novel inodilating compound, were investigated in isolated porcine coronary arteries. Isometric tone was studied on arterial rings precontracted by KCl (30 mM), and resting membrane potential was investigated by a conventional microelectrode technique. ORM-3819 in the concentration range 0.38-230.6 µM evoked concentration-dependent relaxation with a maximum value of 58.1% and an effective concentration of the relaxing substance that caused 50% of maximum relaxation of 72.2 µM. The maximum hyperpolarization produced by ORM-3819 at a concentration of 120 µM (-2.6 ± 0.81 mV, N = 10) did not differ significantly from that induced by C-type natriuretic peptide (CNP), an endogenous hyperpolarizing mediator, at a concentration of 1.4 µM (-3.6 ± 0.38 mV, N = 17). The same effect elicited by the known inodilator levosimendan was less pronounced at a concentration of 3.7 µM: -1.82 ± 0.44 mV, N = 22 (P < 0.05 vs. CNP). The voltage-gated potassium channel inhibitor 4-aminopyridine, at a concentration of 5 mM, attenuated the relaxation induced by ORM-3819 at concentrations of 41.6 or 117.2 µM. These results suggest that ORM-3819 is a potent vasodilating agent able to relieve coronary artery vasospasm by causing hyperpolarization of vascular smooth muscle cells through processes involving activation of voltage-gated potassium channels.
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Babicheva A, Ayon RJ, Zhao T, Ek Vitorin JF, Pohl NM, Yamamura A, Yamamura H, Quinton BA, Ba M, Wu L, Ravellette KS, Rahimi S, Balistrieri F, Harrington A, Vanderpool RR, Thistlethwaite PA, Makino A, Yuan JXJ. MicroRNA-mediated downregulation of K + channels in pulmonary arterial hypertension. Am J Physiol Lung Cell Mol Physiol 2020; 318:L10-L26. [PMID: 31553627 PMCID: PMC6985878 DOI: 10.1152/ajplung.00010.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 08/19/2019] [Accepted: 09/06/2019] [Indexed: 12/22/2022] Open
Abstract
Downregulated expression of K+ channels and decreased K+ currents in pulmonary artery smooth muscle cells (PASMC) have been implicated in the development of sustained pulmonary vasoconstriction and vascular remodeling in patients with idiopathic pulmonary arterial hypertension (IPAH). However, it is unclear exactly how K+ channels are downregulated in IPAH-PASMC. MicroRNAs (miRNAs) are small non-coding RNAs that are capable of posttranscriptionally regulating gene expression by binding to the 3'-untranslated regions of their targeted mRNAs. Here, we report that specific miRNAs are responsible for the decreased K+ channel expression and function in IPAH-PASMC. We identified 3 miRNAs (miR-29b, miR-138, and miR-222) that were highly expressed in IPAH-PASMC in comparison to normal PASMC (>2.5-fold difference). Selectively upregulated miRNAs are correlated with the decreased expression and attenuated activity of K+ channels. Overexpression of miR-29b, miR-138, or miR-222 in normal PASMC significantly decreased whole cell K+ currents and downregulated voltage-gated K+ channel 1.5 (KV1.5/KCNA5) in normal PASMC. Inhibition of miR-29b in IPAH-PASMC completely recovered K+ channel function and KV1.5 expression, while miR-138 and miR-222 had a partial or no effect. Luciferase assays further revealed that KV1.5 is a direct target of miR-29b. Additionally, overexpression of miR-29b in normal PASMC decreased large-conductance Ca2+-activated K+ (BKCa) channel currents and downregulated BKCa channel β1 subunit (BKCaβ1 or KCNMB1) expression, while inhibition of miR-29b in IPAH-PASMC increased BKCa channel activity and BKCaβ1 levels. These data indicate upregulated miR-29b contributes at least partially to the attenuated function and expression of KV and BKCa channels in PASMC from patients with IPAH.
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Affiliation(s)
- Aleksandra Babicheva
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | - Ramon J Ayon
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | - Tengteng Zhao
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | - Jose F Ek Vitorin
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | - Nicole M Pohl
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Aya Yamamura
- Kinjo Gakuin University School of Pharmacy, Nagoya, Japan
| | - Hisao Yamamura
- Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Brooke A Quinton
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | - Manqing Ba
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | - Linda Wu
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | - Keeley S Ravellette
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | - Shamin Rahimi
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
| | - Francesca Balistrieri
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
| | - Angela Harrington
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
| | - Rebecca R Vanderpool
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | | | - Ayako Makino
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, California
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
| | - Jason X-J Yuan
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
- Departments of Medicine and Physiology, The University of Arizona, Tucson, Arizona
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
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Liu Z, Khalil RA. Evolving mechanisms of vascular smooth muscle contraction highlight key targets in vascular disease. Biochem Pharmacol 2018; 153:91-122. [PMID: 29452094 PMCID: PMC5959760 DOI: 10.1016/j.bcp.2018.02.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/12/2018] [Indexed: 12/11/2022]
Abstract
Vascular smooth muscle (VSM) plays an important role in the regulation of vascular function. Identifying the mechanisms of VSM contraction has been a major research goal in order to determine the causes of vascular dysfunction and exaggerated vasoconstriction in vascular disease. Major discoveries over several decades have helped to better understand the mechanisms of VSM contraction. Ca2+ has been established as a major regulator of VSM contraction, and its sources, cytosolic levels, homeostatic mechanisms and subcellular distribution have been defined. Biochemical studies have also suggested that stimulation of Gq protein-coupled membrane receptors activates phospholipase C and promotes the hydrolysis of membrane phospholipids into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). IP3 stimulates initial Ca2+ release from the sarcoplasmic reticulum, and is buttressed by Ca2+ influx through voltage-dependent, receptor-operated, transient receptor potential and store-operated channels. In order to prevent large increases in cytosolic Ca2+ concentration ([Ca2+]c), Ca2+ removal mechanisms promote Ca2+ extrusion via the plasmalemmal Ca2+ pump and Na+/Ca2+ exchanger, and Ca2+ uptake by the sarcoplasmic reticulum and mitochondria, and the coordinated activities of these Ca2+ handling mechanisms help to create subplasmalemmal Ca2+ domains. Threshold increases in [Ca2+]c form a Ca2+-calmodulin complex, which activates myosin light chain (MLC) kinase, and causes MLC phosphorylation, actin-myosin interaction, and VSM contraction. Dissociations in the relationships between [Ca2+]c, MLC phosphorylation, and force have suggested additional Ca2+ sensitization mechanisms. DAG activates protein kinase C (PKC) isoforms, which directly or indirectly via mitogen-activated protein kinase phosphorylate the actin-binding proteins calponin and caldesmon and thereby enhance the myofilaments force sensitivity to Ca2+. PKC-mediated phosphorylation of PKC-potentiated phosphatase inhibitor protein-17 (CPI-17), and RhoA-mediated activation of Rho-kinase (ROCK) inhibit MLC phosphatase and in turn increase MLC phosphorylation and VSM contraction. Abnormalities in the Ca2+ handling mechanisms and PKC and ROCK activity have been associated with vascular dysfunction in multiple vascular disorders. Modulators of [Ca2+]c, PKC and ROCK activity could be useful in mitigating the increased vasoconstriction associated with vascular disease.
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Affiliation(s)
- Zhongwei Liu
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Raouf A Khalil
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA.
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Abstract
Following its initial description over a century ago, pulmonary arterial hypertension (PAH) continues to challenge researchers committed to understanding its pathobiology and finding a cure. The last two decades have seen major developments in our understanding of the genetics and molecular basis of PAH that drive cells within the pulmonary vascular wall to produce obstructive vascular lesions; presently, the field of PAH research has taken numerous approaches to dissect the complex amalgam of genetic, molecular and inflammatory pathways that interact to initiate and drive disease progression. In this review, we discuss the current understanding of PAH pathology and the role that genetic factors and environmental influences share in the development of vascular lesions and abnormal cell function. We also discuss how animal models can assist in elucidating gene function and the study of novel therapeutics, while at the same time addressing the limitations of the most commonly used rodent models. Novel experimental approaches based on application of next generation sequencing, bioinformatics and epigenetics research are also discussed as these are now being actively used to facilitate the discovery of novel gene mutations and mechanisms that regulate gene expression in PAH. Finally, we touch on recent discoveries concerning the role of inflammation and immunity in PAH pathobiology and how they are being targeted with immunomodulatory agents. We conclude that the field of PAH research is actively expanding and the major challenge in the coming years is to develop a unified theory that incorporates genetic and mechanistic data to address viable areas for disease modifying drugs that can target key processes that regulate the evolution of vascular pathology of PAH.
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Affiliation(s)
- Jochen Steppan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD
| | - Dan E Berkowitz
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD
| | - Daniel Nyhan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD
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Ringvold HC, Khalil RA. Protein Kinase C as Regulator of Vascular Smooth Muscle Function and Potential Target in Vascular Disorders. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:203-301. [PMID: 28212798 PMCID: PMC5319769 DOI: 10.1016/bs.apha.2016.06.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Vascular smooth muscle (VSM) plays an important role in maintaining vascular tone. In addition to Ca2+-dependent myosin light chain (MLC) phosphorylation, protein kinase C (PKC) is a major regulator of VSM function. PKC is a family of conventional Ca2+-dependent α, β, and γ, novel Ca2+-independent δ, ɛ, θ, and η, and atypical ξ, and ι/λ isoforms. Inactive PKC is mainly cytosolic, and upon activation it undergoes phosphorylation, maturation, and translocation to the surface membrane, the nucleus, endoplasmic reticulum, and other cell organelles; a process facilitated by scaffold proteins such as RACKs. Activated PKC phosphorylates different substrates including ion channels, pumps, and nuclear proteins. PKC also phosphorylates CPI-17 leading to inhibition of MLC phosphatase, increased MLC phosphorylation, and enhanced VSM contraction. PKC could also initiate a cascade of protein kinases leading to phosphorylation of the actin-binding proteins calponin and caldesmon, increased actin-myosin interaction, and VSM contraction. Increased PKC activity has been associated with vascular disorders including ischemia-reperfusion injury, coronary artery disease, hypertension, and diabetic vasculopathy. PKC inhibitors could test the role of PKC in different systems and could reduce PKC hyperactivity in vascular disorders. First-generation PKC inhibitors such as staurosporine and chelerythrine are not very specific. Isoform-specific PKC inhibitors such as ruboxistaurin have been tested in clinical trials. Target delivery of PKC pseudosubstrate inhibitory peptides and PKC siRNA may be useful in localized vascular disease. Further studies of PKC and its role in VSM should help design isoform-specific PKC modulators that are experimentally potent and clinically safe to target PKC in vascular disease.
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Affiliation(s)
- H C Ringvold
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - R A Khalil
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
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9
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Jernigan NL, Resta TC. Calcium Homeostasis and Sensitization in Pulmonary Arterial Smooth Muscle. Microcirculation 2014; 21:259-71. [DOI: 10.1111/micc.12096] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 09/25/2013] [Indexed: 01/10/2023]
Affiliation(s)
- Nikki L. Jernigan
- Vascular Physiology Group; Department of Cell Biology and Physiology; University of New Mexico Health Sciences Center; Albuquerque New Mexico USA
| | - Thomas C. Resta
- Vascular Physiology Group; Department of Cell Biology and Physiology; University of New Mexico Health Sciences Center; Albuquerque New Mexico USA
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Rieg AD, Suleiman S, Perez-Bouza A, Braunschweig T, Spillner JW, Schröder T, Verjans E, Schälte G, Rossaint R, Uhlig S, Martin C. Milrinone relaxes pulmonary veins in guinea pigs and humans. PLoS One 2014; 9:e87685. [PMID: 24498166 PMCID: PMC3909212 DOI: 10.1371/journal.pone.0087685] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 01/01/2014] [Indexed: 12/14/2022] Open
Abstract
Introduction The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH). However, its action on pulmonary veins (PVs) is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs) and humans. Material and Methods Precision-cut lung slices (PCLS) were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL). Results In the IPL (GP), milrinone (10 µM) lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP), milrinone relaxed naïve and pre-constricted PVs (120%) and this relaxation was attenuated by inhibition of protein kinase G (KT 5823), adenyl cyclase (SQ 22536) and protein kinase A (KT 5720), but not by inhibition of NO-synthesis (L-NAME). In addition, milrinone-induced relaxation was dependent on the activation of KATP-, BKCa2+- and Kv-channels. Human PVs also relaxed to milrinone (121%), however only if pre-constricted. Discussion Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on KATP-, BKCa2+- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.
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Affiliation(s)
- Annette D. Rieg
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
- Department of Anesthesiology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
- * E-mail:
| | - Said Suleiman
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Alberto Perez-Bouza
- Institute of Pathology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
- Institute of Pathology, Medical Faculty of Rhenish Friedrich-Wilhelms University Bonn, Bonn, Germany
| | - Till Braunschweig
- Institute of Pathology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Jan W. Spillner
- Department of Cardiac and Thorax Surgery, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Thomas Schröder
- Department of Surgery, Luisenhospital Aachen, Aachen, Germany
| | - Eva Verjans
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
- Department of Pediatrics, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Gereon Schälte
- Department of Anesthesiology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Rolf Rossaint
- Department of Anesthesiology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Stefan Uhlig
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
| | - Christian Martin
- Institute of Pharmacology and Toxicology, Medical Faculty of Rhenish-Westphalian Technical University Aachen, Aachen, Germany
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Yan J, Chen R, Liu P, Gu Y. Docosahexaenoic acid attenuates hypoxic pulmonary vasoconstriction by activating the large conductance Ca2+-activated K+ currents in pulmonary artery smooth muscle cells. Pulm Pharmacol Ther 2013; 28:9-16. [PMID: 24269522 DOI: 10.1016/j.pupt.2013.11.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 10/14/2013] [Accepted: 11/11/2013] [Indexed: 01/31/2023]
Abstract
BACKGROUND The inhibition of potassium (K(+)) channels plays an important role in pulmonary circulation for its close relationship with hypoxic pulmonary vasoconstriction (HPV). Docosahexaenoic acid (DHA), a n-3 polyunsaturated fatty acid, is well known for its prevention and treatment of cardiovascular diseases. However the role which DHA plays in HPV remains unclear. Here, we tested the hypothesis that DHA contributes to pulmonary vascular tone by activating the large conductance Ca(2+)-activated K(+) (BKCa) channels via calcium sparks. METHODS AND RESULTS Isolated resistance pulmonary artery preparation was used to study the vasomotor response to DHA. Pulmonary artery smooth muscle cells (PASMCs) were isolated from third- to fourth order branches of pulmonary arteries by collagenase digestion method. BKCa and the voltage-dependent potassium channel (Kv) currents in PASMCs were measured by the whole-cell patch-clamp technique. Fluo-8 was used as a fluorescence indicator for the real-time measurement of calcium dynamics in PASMCs. DHA dilated resistance pulmonary arteries in a dose-dependent manner in hypoxic or normoxic solution, and the effects of DHA were abolished after pre-treatment with heparin (100 μg/ml), a 1,4,5-triphosphate (IP3) receptor (IP3R) inhibitor or iberiotoxin (100 nmol/L), a specific inhibitor of BKCa channel. DHA activated BKCa channels in a dose-dependent manner, however, the activation induced by DHA was not seen in PASMCs pre-incubated with heparin. While the Kv currents decreased from 102.6 ± 5.4 to 36.5 ± 6.7 pA/pF by addition of 10 μmol/L DHA. DHA also caused calcium sparks in PASMCs. Moreover, hypoxia inhibited BKCa currents in PASMCs, but this inhibition was reversed by DHA. CONCLUSION Our findings suggest that DHA is a novel BKCa opener in PASMCs, which may indicate a potential therapeutic role in HPV.
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Affiliation(s)
- Jinchuan Yan
- Department of Cardiology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu Province 212001, China.
| | - Rui Chen
- Department of Cardiology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu Province 212001, China
| | - Peijing Liu
- Department of Cardiology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu Province 212001, China.
| | - Yuchun Gu
- Institute of Molecular Medicine, Peking University, Beijing 100871, China
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Murray F, Maclean MR, Insel PA. Role of phosphodiesterases in adult-onset pulmonary arterial hypertension. Handb Exp Pharmacol 2011:279-305. [PMID: 21695645 DOI: 10.1007/978-3-642-17969-3_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Pulmonary arterial hypertension (PAH) is characterized by increased mean pulmonary artery pressure (mPAP) due to vasoconstriction and structural changes in the small pulmonary arteries (PAs); proliferation of pulmonary artery smooth muscle cells (PASMCs) contributes to the remodeling. The abnormal pathophysiology in the pulmonary vasculature relates to decreased cyclic nucleotide levels in PASMCs. Phosphodiesterases (PDEs) catalyze the hydrolysis of cAMP and cGMP, thereby PDE inhibitors are effective in vasodilating the PA and decreasing PASMC proliferation. Experimental studies support the use of PDE3, PDE5, and PDE1 inhibitors in PAH. PDE5 inhibitors such as sildenafil are clinically approved to treat different forms of PAH and lower mPAP, increase functional capacity, and decrease right ventricular hypertrophy, without decreasing systemic arterial pressure. New evidence suggests that the combination of PDE inhibitors with other therapies for PAH may be beneficial in treating the disease. Furthermore, inhibiting PDEs in the heart and the inflammatory cells that infiltrate the PA may offer new targets to reduce right ventricular hypertrophy and inhibit inflammation that is associated with and contributes to the development of PAH. This chapter summarizes the advances in the area and the future of PDEs in PAH.
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Affiliation(s)
- F Murray
- Department of Pharmacology and Department of Medicine, BSB 3073, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093-0636, USA.
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