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Aubin Vega M, Girault A, Meunier É, Chebli J, Privé A, Robichaud A, Adam D, Brochiero E. Function of KvLQT1 potassium channels in a mouse model of bleomycin-induced acute lung injury. Front Physiol 2024; 15:1345488. [PMID: 38444763 PMCID: PMC10912346 DOI: 10.3389/fphys.2024.1345488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/30/2024] [Indexed: 03/07/2024] Open
Abstract
Acute respiratory distress syndrome (ARDS) is characterized by an exacerbated inflammatory response, severe damage to the alveolar-capillary barrier and a secondary infiltration of protein-rich fluid into the airspaces, ultimately leading to respiratory failure. Resolution of ARDS depends on the ability of the alveolar epithelium to reabsorb lung fluid through active transepithelial ion transport, to control the inflammatory response, and to restore a cohesive and functional epithelium through effective repair processes. Interestingly, several lines of evidence have demonstrated the important role of potassium (K+) channels in the regulation of epithelial repair processes. Furthermore, these channels have previously been shown to be involved in sodium/fluid absorption across alveolar epithelial cells, and we have recently demonstrated the contribution of KvLQT1 channels to the resolution of thiourea-induced pulmonary edema in vivo. The aim of our study was to investigate the role of the KCNQ1 pore-forming subunit of KvLQT1 channels in the outcome of ARDS parameters in a model of acute lung injury (ALI). We used a molecular approach with KvLQT1-KO mice challenged with bleomycin, a well-established ALI model that mimics the key features of the exudative phase of ARDS on day 7. Our data showed that KvLQT1 deletion exacerbated the negative outcome of bleomycin on lung function (resistance, elastance and compliance). An alteration in the profile of infiltrating immune cells was also observed in KvLQT1-KO mice while histological analysis showed less interstitial and/or alveolar inflammatory response induced by bleomycin in KvLQT1-KO mice. Finally, a reduced repair rate of KvLQT1-KO alveolar cells after injury was observed. This work highlights the complex contribution of KvLQT1 in the development and resolution of ARDS parameters in a model of ALI.
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Affiliation(s)
- Mélissa Aubin Vega
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Alban Girault
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
- Laboratoire de Physiologie Cellulaire et Moléculaire (LPCM UR UPJV 4667), Amiens, France
| | - Émilie Meunier
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Jasmine Chebli
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Anik Privé
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
| | | | - Damien Adam
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Emmanuelle Brochiero
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
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2
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Sytha SP, Self TS, Heaps CL. K + channels in the coronary microvasculature of the ischemic heart. CURRENT TOPICS IN MEMBRANES 2022; 90:141-166. [PMID: 36368873 PMCID: PMC10494550 DOI: 10.1016/bs.ctm.2022.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ischemic heart disease is the leading cause of death and a major public health and economic burden worldwide with expectations of predicted growth in the foreseeable future. It is now recognized clinically that flow-limiting stenosis of the large coronary conduit arteries as well as microvascular dysfunction in the absence of severe stenosis can each contribute to the etiology of ischemic heart disease. The primary site of coronary vascular resistance, and control of subsequent coronary blood flow, is found in the coronary microvasculature, where small changes in radius can have profound impacts on myocardial perfusion. Basal active tone and responses to vasodilators and vasoconstrictors are paramount in the regulation of coronary blood flow and adaptations in signaling associated with ion channels are a major factor in determining alterations in vascular resistance and thereby myocardial blood flow. K+ channels are of particular importance as contributors to all aspects of the regulation of arteriole resistance and control of perfusion into the myocardium because these channels dictate membrane potential, the resultant activity of voltage-gated calcium channels, and thereby, the contractile state of smooth muscle. Evidence also suggests that K+ channels play a significant role in adaptations with cardiovascular disease states. In this review, we highlight our research examining the role of K+ channels in ischemic heart disease and adaptations with exercise training as treatment, as well as how our findings have contributed to this area of study.
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Affiliation(s)
- Sharanee P Sytha
- Department of Physiology and Pharmacology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Trevor S Self
- Department of Physiology and Pharmacology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Cristine L Heaps
- Department of Physiology and Pharmacology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States; Michael E. DeBakey Institute for Comparative Cardiovascular Science and Biomedical Devices, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States.
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3
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Peixoto-Neves D, Kanthakumar P, Afolabi JM, Soni H, Buddington RK, Adebiyi A. K V7.1 channel blockade inhibits neonatal renal autoregulation triggered by a step decrease in arterial pressure. Am J Physiol Renal Physiol 2022; 322:F197-F207. [PMID: 35001664 PMCID: PMC8816635 DOI: 10.1152/ajprenal.00568.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
KV7 channels, the voltage-gated K+ channels encoded by KCNQ genes, mediate heterogeneous vascular responses in rodents. Postnatal changes in the functional expression of KV7 channels have been reported in rodent saphenous arteries, but their physiological function in the neonatal renal vascular bed is unclear. Here, we report that, unlike adult pigs, only KCNQ1 (KV7.1) out of the five members of KCNQ genes was detected in neonatal pig renal microvessels. KCNQ1 is present in fetal pig kidneys as early as day 50 of gestation, and the level of expression remains the same up to postnatal day 21. Activation of renal vascular smooth muscle cell (SMC) KV7.1 stimulated whole cell currents, inhibited by HMR1556 (HMR), a selective KV7.1 blocker. HMR did not change the steady-state diameter of isolated renal microvessels. Similarly, intrarenal artery infusion of HMR did not alter mean arterial pressure, renal blood flow, and renal vascular resistance in the pigs. An ∼20 mmHg reduction in mean arterial pressure evoked effective autoregulation of renal blood flow, which HMR inhibited. We conclude that 1) the expression of KCNQ isoforms in porcine renal microvessels is dependent on kidney maturation, 2) KV7.1 is functionally expressed in neonatal pig renal vascular SMCs, 3) a decrease in arterial pressure up to 20 mmHg induces renal autoregulation in neonatal pigs, and 4) SMC KV7.1 does not control basal renal vascular tone but contributes to neonatal renal autoregulation triggered by a step decrease in arterial pressure.NEW & NOTEWORTHY KV7.1 is present in fetal pig kidneys as early as day 50 of gestation, and the level of expression remains the same up to postnatal day 21. KV7.1 is functionally expressed in neonatal pig renal vascular smooth muscle cells (SMCs). A decrease in arterial pressure up to 20 mmHg induces renal autoregulation in neonatal pigs. Although SMC KV7.1 does not control basal renal vascular resistance, its inhibition blunts neonatal renal autoregulation engendered by a step decrease in arterial pressure.
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Affiliation(s)
- Dieniffer Peixoto-Neves
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Jeremiah M. Afolabi
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Hitesh Soni
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Adebowale Adebiyi
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
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4
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Beck L, Pinilla E, Arcanjo DDR, Hernanz R, Prat-Duran J, Petersen AG, Köhler R, Sheykhzade M, Comerma-Steffensen S, Simonsen U. Pirfenidone Is a Vasodilator: Involvement of K V7 Channels in the Effect on Endothelium-Dependent Vasodilatation in Type-2 Diabetic Mice. Front Pharmacol 2021; 11:619152. [PMID: 33643042 PMCID: PMC7906977 DOI: 10.3389/fphar.2020.619152] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/30/2020] [Indexed: 12/27/2022] Open
Abstract
Endothelial cell dysfunction and fibrosis are associated with worsening of the prognosis in patients with cardiovascular disease. Pirfenidone has a direct antifibrotic effect, but vasodilatation may also contribute to the effects of pirfenidone. Therefore, in a first study we investigated the mechanisms involved in the relaxant effect of pirfenidone in rat intrapulmonary arteries and coronary arteries from normal mice. Then in a second study, we investigated whether pirfenidone restores endothelial function in the aorta and mesenteric arteries from diabetic animals. From 16–18-week old normal male C57BL/6 mice and normoglycemic (db/db+), and type 2 diabetic (db/db) male and female mice, arteries were mounted in microvascular isometric myographs for functional studies, and immunoblotting was performed. In rat pulmonary arteries and mouse coronary arteries, pirfenidone induced relaxations, which were inhibited in preparations without endothelium. In mouse coronary arteries, pirfenidone relaxation was inhibited in the presence of a nitric oxide (NO) synthase inhibitor, NG-nitro-l-arginine (L-NOARG), a blocker of large-conductance calcium-activated potassium channels (BKCa), iberiotoxin, and a blocker of KV7 channels, XE991. Patch clamp studies in vascular smooth muscle revealed pirfenidone increased iberiotoxin-sensitive current. In the aorta and mesenteric small arteries from diabetic db/db mice relaxations induced by the endothelium-dependent vasodilator, acetylcholine, were markedly reduced compared to db/db + mice. Pirfenidone enhanced the relaxations induced by acetylcholine in the aorta from diabetic male and female db/db mice. An opener of KV7 channels, flupirtine, had the same effect as pirfenidone. XE991 reduced the effect of pirfenidone and flupirtine and further reduced acetylcholine relaxations in the aorta. In the presence of iberiotoxin, pirfenidone still increased acetylcholine relaxation in aorta from db/db mice. Immunoblotting for KV7.4, KV7.5, and BKCa channel subunits were unaltered in aorta from db/db mice. Pirfenidone failed to improve acetylcholine relaxation in mesenteric arteries, and neither changed acetylcholine-induced transient decreases in blood pressure in db/db+ and db/db mice. In conclusion, pirfenidone vasodilates pulmonary and coronary arteries. In coronary arteries from normal mice, pirfenidone induces NO-dependent vasodilatation involving BKCa and KV7 channels. Pirfenidone improves endothelium-dependent vasodilatation in aorta from diabetic animals by a mechanism involving voltage-gated KV7 channels, a mechanism that may contribute to the antifibrotic effect of pirfenidone.
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Affiliation(s)
- Lilliana Beck
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark
| | - Estéfano Pinilla
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark.,Department of Physiology, Faculty of Pharmacy, Universidad Complutense, Madrid, Spain
| | - Daniel Dias Rufino Arcanjo
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark.,Department of Biophysics and Physiology, Laboratory of Functional and Molecular Studies in Physiopharmacology, Federal University of Piauí, Teresina, Brazil
| | - Raquel Hernanz
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark.,Departamento de Ciencias Básicas de la Salud, Universidad Rey Juan Carlos, Alcorcón, Spain
| | - Judit Prat-Duran
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark
| | - Asbjørn Graver Petersen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark
| | - Ralf Köhler
- Aragón Agency for Research and Development (ARAID), Zaragoza, Spain
| | - Majid Sheykhzade
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Simon Comerma-Steffensen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark.,Department of Biomedical Sciences/Animal Physiology, Faculty of Veterinary, Central University of Venezuela, Maracay, Venezuela
| | - Ulf Simonsen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark
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5
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Hung TY, Huang CW, Wu SN. High ability of zileuton ((±)-1-(1-benzo[b]thien-2-ylethyl)-1-hydroxyurea) to stimulate I K(Ca) but suppress I K(DR) and I K(M) independently of 5-lipoxygenase inhibition. Eur J Pharmacol 2020; 887:173482. [PMID: 32795513 DOI: 10.1016/j.ejphar.2020.173482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 08/07/2020] [Accepted: 08/08/2020] [Indexed: 12/16/2022]
Abstract
Zileuton (Zyflo®) is regarded to be an inhibitor of 5-lipoxygenase. Although its effect on Ca2+-activated K+ currents has been reported, its overall ionic effects on neurons are uncertain. In whole-cell current recordings, zileuton increased the amplitude of Ca2+-activated K+ currents with an EC50 of 3.2 μM in pituitary GH3 lactotrophs. Furthermore, zileuton decreased the amplitudes of both delayed-rectifier K+ current (IK(DR)) and M-type K+ current (IK(M)). Conversely, no modification of hyperpolarization-activated cation current (Ih) was demonstrated in its presence of zileuton, although the subsequent addition of cilobradine effectively suppressed the current. In inside-out current recordings, the addition of zileuton to the bath increased the probability of large-conductance Ca2+-activated K+ (BKCa) channels; however, the subsequent addition of GAL-021 effectively reversed the stimulation of channel activity. The kinetic analyses showed an evident shortening in the slow component of mean closed time of BKCa channels in the presence of zileuton, with minimal change in mean open time or that in the fast component of mean closed time. The elevation of BKCa channels caused by zileuton was also observed in hippocampal mHippoE-14 neurons, without any modification of single-channel amplitude. In conclusion, except for its suppression of 5-lipoxygenase, our results indicate that zileuton does not exclusively act on BKCa channels, and its inhibitory effects on IK(DR) and IK(M) may combine to exert strong influence on the functional activities of electrically excitable cells in vivo.
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Affiliation(s)
- Te-Yu Hung
- Department of Pediatrics, Chi-Mei Medical Center, Tainan, Taiwan
| | - Chin-Wei Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan; Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung City, Taiwan.
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6
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Mondejar-Parreño G, Perez-Vizcaino F, Cogolludo A. Kv7 Channels in Lung Diseases. Front Physiol 2020; 11:634. [PMID: 32676036 PMCID: PMC7333540 DOI: 10.3389/fphys.2020.00634] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/18/2020] [Indexed: 12/23/2022] Open
Abstract
Lung diseases constitute a global health concern causing disability. According to WHO in 2016, respiratory diseases accounted for 24% of world population mortality, the second cause of death after cardiovascular diseases. The Kv7 channels family is a group of voltage-dependent K+ channels (Kv) encoded by KCNQ genes that are involved in various physiological functions in numerous cell types, especially, cardiac myocytes, smooth muscle cells, neurons, and epithelial cells. Kv7 channel α-subunits are regulated by KCNE1–5 ancillary β-subunits, which modulate several characteristics of Kv7 channels such as biophysical properties, cell-location, channel trafficking, and pharmacological sensitivity. Kv7 channels are mainly expressed in two large groups of lung tissues: pulmonary arteries (PAs) and bronchial tubes. In PA, Kv7 channels are expressed in pulmonary artery smooth muscle cells (PASMCs); while in the airway (trachea, bronchus, and bronchioles), Kv7 channels are expressed in airway smooth muscle cells (ASMCs), airway epithelial cells (AEPs), and vagal airway C-fibers (VACFs). The functional role of Kv7 channels may vary depending on the cell type. Several studies have demonstrated that the impairment of Kv7 channel has a strong impact on pulmonary physiology contributing to the pathophysiology of different respiratory diseases such as cystic fibrosis, asthma, chronic obstructive pulmonary disease, chronic coughing, lung cancer, and pulmonary hypertension. Kv7 channels are now recognized as playing relevant physiological roles in many tissues, which have encouraged the search for Kv7 channel modulators with potential therapeutic use in many diseases including those affecting the lung. Modulation of Kv7 channels has been proposed to provide beneficial effects in a number of lung conditions. Therefore, Kv7 channel openers/enhancers or drugs acting partly through these channels have been proposed as bronchodilators, expectorants, antitussives, chemotherapeutics and pulmonary vasodilators.
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Affiliation(s)
- Gema Mondejar-Parreño
- Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.,Ciber Enfermedades Respiratorias (Ciberes), Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain
| | - Francisco Perez-Vizcaino
- Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.,Ciber Enfermedades Respiratorias (Ciberes), Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain
| | - Angel Cogolludo
- Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.,Ciber Enfermedades Respiratorias (Ciberes), Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain
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7
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Kim JO, Lee KO, Kim HW, Park HS, Kim J, Sung JH, Oh D, Kim OJ, Kim NK. Association between KCNQ2, TCF4 and RGS18 polymorphisms and silent brain infarction based on whole‑exome sequencing. Mol Med Rep 2020; 21:1973-1983. [PMID: 32319632 DOI: 10.3892/mmr.2020.10975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/20/2020] [Indexed: 11/05/2022] Open
Abstract
Silent brain infarction (SBI) is a cerebral infarction identified through brain imaging. In particular, studies have shown that the presence of SBI in elderly patients increases their risk of cognitive dysfunction, impairment and dementia. However, little research has been published on the relevance of SBI to these risks for the Korean population. The association between potassium voltage‑gated channel subfamily Q member 2 (KCNQ2), transcription factor 4 (TCF4) and regulator of G‑protein signaling 18 (RGS18) genotypes and SBI were investigated using whole‑exome sequencing and PCR restriction fragment length polymorphism (RFLP) analysis. The study population included 407 patients with SBI (171 males) and 401 control subjects (172 males). Genotyping was performed using PCR RFLP. Interestingly, TCF4 rs9957668T>C polymorphisms were associated with SBI prevalence [TT vs. CC: adjusted odds ratio (AOR), 1.815, 95% confidence intervals (CI), 1.202‑2.740; TT vs. TC+CC: AOR, 1.492, 95% CI, 1.066‑2.088; TT+TC vs. CC: AOR, 1.454, 95% CI, 1.045‑2.203]. The combination of KCNQ2 rs73146513A>G and TCF4 rs9957668T>C genotypes was associated with increasing SBI prevalence (AG/CC: AOR, 3.719, 95% CI, 1.766‑7.833; AA/CC: AOR, 3.201, 95% CI, 1.387‑7.387). The present study showed that TCF4 rs9957668T>C polymorphisms may be risk factors for SBI. Therefore, the TCF4 rs9957668T>C polymorphism may serve as a biomarker for increased risk of SBI in the Korean population.
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Affiliation(s)
- Jung Oh Kim
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Republic of Korea
| | - Kee Ook Lee
- Department of Neurology, CHA Bundang Medical Center, School of Medicine, CHA University, Seongnam, Gyeonggi 13496, Republic of Korea
| | - Hyun Woo Kim
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Republic of Korea
| | - Han Sung Park
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Republic of Korea
| | - Jinkwon Kim
- Department of Neurology, CHA Bundang Medical Center, School of Medicine, CHA University, Seongnam, Gyeonggi 13496, Republic of Korea
| | - Jung Hoon Sung
- Department of Cardiology, CHA Bundang Medical Center, School of Medicine, CHA University, Seongnam, Gyeonggi 13496, Republic of Korea
| | - Doyeun Oh
- Department of Internal Medicine, CHA Bundang Medical Center, School of Medicine, CHA University, Seongnam, Gyeonggi 13496, Republic of Korea
| | - Ok Joon Kim
- Department of Neurology, CHA Bundang Medical Center, School of Medicine, CHA University, Seongnam, Gyeonggi 13496, Republic of Korea
| | - Nam Keun Kim
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Republic of Korea
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8
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Fu L, Jiang G, Weng H, Dick GM, Chang Y, Kassab GS. Cerebrovascular miRNAs correlate with the clearance of Aβ through perivascular route in younger 3xTg-AD mice. Brain Pathol 2019; 30:92-105. [PMID: 31206909 DOI: 10.1111/bpa.12759] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 06/04/2019] [Indexed: 12/14/2022] Open
Abstract
The "two-hit vascular hypothesis for Alzheimer's disease (AD)" and amyloid-β (Aβ) oligomer hypothesis suggest that impaired soluble Aβ oligomers clearance through the cerebral vasculature may be an initial step of the AD process. Soluble Aβ oligomers are driven into perivascular spaces from the brain parenchyma and toward peripheral blood flow. The underlying vascular-based mechanism, however, has not been defined. Given that microRNAs (miRNAs), emerging as novel modulators, are involved in numerous physiological and pathological processes, we hypothesized that cerebrovascular miRNAs may regulate the activities of brain blood vessels, which further affects the concentration of Aβ in the AD brain. In this study, perivascular Aβ deposits, higher vascular activation, increased pericyte coverage and up-regulated capillaries miRNAs at 6 months old (6 mo) were found to correlate with the lower Aβ levels of middle AD stage (9 mo) in 3xTg-AD (3xTg) mice. It is implicated that at the early stage of AD when intracellular Aβ appeared, higher expression of vessel-specific miRNAs, elevated pericyte coverage, and activated endothelium facilitate Aβ oligomer clearance through the perivascular route, resulting in a transient reduction of Aβ oligomers at 9 mo. Additionally, ghrelin-induced upregulation of capillary miRNAs and increased pericyte coverage attenuated Aβ burden at 9 mo, in further support of the relationship between vascular miRNAs and Aβ clearance. This work suggests a cerebral microvessel miRNA may boost endothelial highly activated phenotypes to promote elimination of Aβ oligomers through the perivascular drainage pathway and contribute to AD progression. The targeting of brain vessel-specific miRNAs may provide a new rationale for the development of innovative therapeutic strategies for AD treatment.
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Affiliation(s)
- Lijuan Fu
- California Medical Innovations Institute, San Diego, USA
| | - Ge Jiang
- California Medical Innovations Institute, San Diego, USA
| | - Hope Weng
- California Medical Innovations Institute, San Diego, USA
| | - Gregory M Dick
- California Medical Innovations Institute, San Diego, USA
| | - Yanzhong Chang
- Laboratory of Molecular Iron Metabolism, College of Life Science, Hebei Normal University, Shijiazhuang, China
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9
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Lawson K. Pharmacology and clinical applications of flupirtine: Current and future options. World J Pharmacol 2019; 8:1-13. [DOI: 10.5497/wjp.v8.i1.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/17/2018] [Accepted: 01/05/2019] [Indexed: 02/06/2023] Open
Abstract
Flupirtine is the first representative in a class of triaminopyridines that exhibits pharmacological properties leading to the suppression of over-excitability of neuronal and non-neuronal cells. Consequently, this drug has been used as a centrally acting analgesic in patients with a range of acute and persistent pain conditions without the adverse effects characteristic of opioids and non-steroidal anti-inflammatory drug and is well tolerated. The pharmacological profile exhibited involves actions on several cellular targets, including Kv7 channels, G-protein-regulated inwardly rectifying K channels and γ-aminobutyric acid type A receptors, but also there is evidence of additional as yet unidentified mechanisms of action involved in the effects of flupirtine. Flupirtine has exhibited effects in a range of cells and tissues related to the locations of these targets. In additional to analgesia, flupirtine has demonstrated pharmacological properties consistent with use as an anticonvulsant, a neuroprotectant, skeletal and smooth muscle relaxant, in treatment of auditory and visual disorders, and treatment of memory and cognitive impairment. Flupirtine is providing important information and clues regarding novel mechanistic approaches to the treatment of a range of clinical conditions involving hyper-excitability of cells. Identification of molecules exhibiting specificity for the pharmacological targets (e.g., Kv7 isoforms) involved in the actions of flupirtine will provide further insight into clinical applications. Whether the broad-spectrum pharmacology of flupirtine or target-specific actions is preferential to gain benefit, especially in complex clinical conditions, requires further investigation. This review will consider recent advancement in understanding of the pharmacological profile and related clinical applications of flupirtine.
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Affiliation(s)
- Kim Lawson
- Department of Biosciences and Chemistry, Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield S1 1WB, United Kingdom
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10
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Gollasch M, Welsh DG, Schubert R. Perivascular adipose tissue and the dynamic regulation of K v 7 and K ir channels: Implications for resistant hypertension. Microcirculation 2018; 25. [PMID: 29211322 DOI: 10.1111/micc.12434] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/30/2017] [Indexed: 12/20/2022]
Abstract
Resistant hypertension is defined as high blood pressure that remains uncontrolled despite treatment with at least three antihypertensive drugs at adequate doses. Resistant hypertension is an increasingly common clinical problem in older age, obesity, diabetes, sleep apnea, and chronic kidney disease. Although the direct vasodilator minoxidil was introduced in the early 1970s, only recently has this drug been shown to be particularly effective in a subgroup of patients with treatment-resistant or uncontrolled hypertension. This pharmacological approach is interesting from a mechanistic perspective as minoxidil is the only clinically used K+ channel opener today, which targets a subclass of K+ channels, namely KATP channels in VSMCs. Beside KATP channels, two other classes of VSMC K+ channels could represent novel effective targets for treatment of resistant hypertension, namely Kv 7 (KCNQ) and inward rectifier potassium (Kir 2.1) channels. Interestingly, these channels are unique among VSMC potassium channels. First, both have been implicated in the control of microvascular tone by perivascular adipose tissue. Second, they exhibit biophysical properties strongly controlled and regulated by membrane voltage, but not intracellular calcium. This review focuses on Kv 7 (Kv 7.1-5) and Kir (Kir 2.1) channels in VSMCs as potential novel drug targets for treatment of resistant hypertension, particularly in comorbid conditions such as obesity and metabolic syndrome.
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Affiliation(s)
- Maik Gollasch
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum, Experimental and Clinical Research Center (ECRC) - a joint cooperation between the Charité - University Medicine Berlin and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Donald G Welsh
- Department of Physiology and Pharmacology, Western University, London, ON, Canada
| | - Rudolf Schubert
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
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11
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Nassoiy SP, Babu FS, LaPorte HM, Byron KL, Majetschak M. Effects of the Kv7 voltage-activated potassium channel inhibitor linopirdine in rat models of haemorrhagic shock. Clin Exp Pharmacol Physiol 2018; 45:10.1111/1440-1681.12958. [PMID: 29702725 PMCID: PMC6204121 DOI: 10.1111/1440-1681.12958] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/13/2018] [Accepted: 04/20/2018] [Indexed: 12/12/2022]
Abstract
Recently, we demonstrated that Kv7 voltage-activated potassium channel inhibitors reduce fluid resuscitation requirements in short-term rat models of haemorrhagic shock. The aim of the present study was to further delineate the therapeutic potential and side effect profile of the Kv7 channel blocker linopirdine in various rat models of severe haemorrhagic shock over clinically relevant time periods. Intravenous administration of linopirdine, either before (1 or 3 mg/kg) or after (3 mg/kg) a 40% blood volume haemorrhage, did not affect blood pressure and survival in lethal haemorrhage models without fluid resuscitation. A single bolus of linopirdine (3 mg/kg) at the beginning of fluid resuscitation after haemorrhagic shock transiently reduced early fluid requirements in spontaneously breathing animals that were resuscitated for 3.5 hours. When mechanically ventilated rats were resuscitated after haemorrhagic shock with normal saline (NS) or with linopirdine-supplemented (10, 25 or 50 μg/mL) NS for 4.5 hours, linopirdine significantly and dose-dependently reduced fluid requirements by 14%, 45% and 55%, respectively. Lung and colon wet/dry weight ratios were reduced with linopirdine (25/50 μg/mL). There was no evidence for toxicity or adverse effects based on measurements of routine laboratory parameters and inflammation markers in plasma and tissue homogenates. Our findings support the concept that linopirdine-supplementation of resuscitation fluids is a safe and effective approach to reduce fluid requirements and tissue oedema formation during resuscitation from haemorrhagic shock.
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Affiliation(s)
- Sean P. Nassoiy
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago, Stritch School of Medicine
| | - Favin S. Babu
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago, Stritch School of Medicine
| | - Heather M. LaPorte
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago, Stritch School of Medicine
| | - Kenneth L. Byron
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Stritch School of Medicine
| | - Matthias Majetschak
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago, Stritch School of Medicine
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Stritch School of Medicine
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12
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Kiel AM, Goodwill AG, Noblet JN, Barnard AL, Sassoon DJ, Tune JD. Regulation of myocardial oxygen delivery in response to graded reductions in hematocrit: role of K + channels. Basic Res Cardiol 2017; 112:65. [PMID: 28965130 DOI: 10.1007/s00395-017-0654-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/25/2017] [Indexed: 01/10/2023]
Abstract
This study was designed to identify mechanisms responsible for coronary vasodilation in response to progressive decreases in hematocrit. Isovolemic hemodilution was produced in open-chest, anesthetized swine via concurrent removal of 500 ml of arterial blood and the addition of 500 ml of 37 °C saline or synthetic plasma expander (Hespan, 6% hetastarch in 0.9% sodium chloride). Progressive hemodilution with Hespan resulted in an increase in coronary flow from 0.39 ± 0.05 to 1.63 ± 0.16 ml/min/g (P < 0.001) as hematocrit was reduced from 32 ± 1 to 10 ± 1% (P < 0.001). Overall, coronary flow corresponded with the level of myocardial oxygen consumption, was dependent on arterial pressures ≥ ~ 60 mmHg, and occurred with little/no change in coronary venous PO2. Anemic coronary vasodilation was unaffected by the inhibition of nitric oxide synthase (L-NAME: 25 mg/kg iv; P = 0.92) or voltage-dependent K+ (K V) channels (4-aminopyridine: 0.3 mg/kg iv; P = 0.52). However, administration of the K ATP channel antagonist (glibenclamide: 3.6 mg/kg iv) resulted in an ~ 40% decrease in coronary blood flow (P < 0.001) as hematocrit was reduced to ~ 10%. These reductions in coronary blood flow corresponded with significant reductions in myocardial oxygen delivery at baseline and throughout isovolemic anemia (P < 0.001). These data indicate that vasodilator factors produced in response to isovolemic hemodilution converge on vascular smooth muscle glibenclamide-sensitive (K ATP) channels to maintain myocardial oxygen delivery and that this response is not dependent on endothelial-derived nitric oxide production or pathways that mediate dilation via K V channels.
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Affiliation(s)
- Alexander M Kiel
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Adam G Goodwill
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Jillian N Noblet
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - April L Barnard
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Daniel J Sassoon
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Johnathan D Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA.
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13
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Abstract
The heart is uniquely responsible for providing its own blood supply through the coronary circulation. Regulation of coronary blood flow is quite complex and, after over 100 years of dedicated research, is understood to be dictated through multiple mechanisms that include extravascular compressive forces (tissue pressure), coronary perfusion pressure, myogenic, local metabolic, endothelial as well as neural and hormonal influences. While each of these determinants can have profound influence over myocardial perfusion, largely through effects on end-effector ion channels, these mechanisms collectively modulate coronary vascular resistance and act to ensure that the myocardial requirements for oxygen and substrates are adequately provided by the coronary circulation. The purpose of this series of Comprehensive Physiology is to highlight current knowledge regarding the physiologic regulation of coronary blood flow, with emphasis on functional anatomy and the interplay between the physical and biological determinants of myocardial oxygen delivery. © 2017 American Physiological Society. Compr Physiol 7:321-382, 2017.
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Affiliation(s)
- Adam G Goodwill
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Gregory M Dick
- California Medical Innovations Institute, 872 Towne Center Drive, Pomona, CA
| | - Alexander M Kiel
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Drive, Lafayette, IN
| | - Johnathan D Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
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14
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 212] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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15
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Nishijima Y, Cao S, Chabowski DS, Korishettar A, Ge A, Zheng X, Sparapani R, Gutterman DD, Zhang DX. Contribution of K V1.5 Channel to Hydrogen Peroxide-Induced Human Arteriolar Dilation and Its Modulation by Coronary Artery Disease. Circ Res 2016; 120:658-669. [PMID: 27872049 DOI: 10.1161/circresaha.116.309491] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 11/11/2016] [Accepted: 11/21/2016] [Indexed: 02/06/2023]
Abstract
RATIONALE Hydrogen peroxide (H2O2) regulates vascular tone in the human microcirculation under physiological and pathophysiological conditions. It dilates arterioles by activating large-conductance Ca2+-activated K+ channels in subjects with coronary artery disease (CAD), but its mechanisms of action in subjects without CAD (non-CAD) when compared with those with CAD remain unknown. OBJECTIVE We hypothesize that H2O2-elicited dilation involves different K+ channels in non-CAD versus CAD, resulting in an altered capacity for vasodilation during disease. METHODS AND RESULTS H2O2 induced endothelium-independent vasodilation in non-CAD adipose arterioles, which was reduced by paxilline, a large-conductance Ca2+-activated K+ channel blocker, and by 4-aminopyridine, a voltage-gated K+ (KV) channel blocker. Assays of mRNA transcripts, protein expression, and subcellular localization revealed that KV1.5 is the major KV1 channel expressed in vascular smooth muscle cells and is abundantly localized on the plasma membrane. The selective KV1.5 blocker diphenylphosphine oxide-1 and the KV1.3/1.5 blocker 5-(4-phenylbutoxy)psoralen reduced H2O2-elicited dilation to a similar extent as 4-aminopyridine, but the selective KV1.3 blocker phenoxyalkoxypsoralen-1 was without effect. In arterioles from CAD subjects, H2O2-induced dilation was significantly reduced, and this dilation was inhibited by paxilline but not by 4-aminopyridine, diphenylphosphine oxide-1, or 5-(4-phenylbutoxy)psoralen. KV1.5 cell membrane localization and diphenylphosphine oxide-1-sensitive K+ currents were markedly reduced in isolated vascular smooth muscle cells from CAD arterioles, although mRNA or total cellular protein expression was largely unchanged. CONCLUSIONS In human arterioles, H2O2-induced dilation is impaired in CAD, which is associated with a transition from a combined large-conductance Ca2+-activated K+- and KV (KV1.5)-mediated vasodilation toward a large-conductance Ca2+-activated K+-predominant mechanism of dilation. Loss of KV1.5 vasomotor function may play an important role in microvascular dysfunction in CAD or other vascular diseases.
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Affiliation(s)
- Yoshinori Nishijima
- From the Department of Medicine (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Cardiovascular Center (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Department of Pharmacology and Toxicology (D.S.C., A.K.), Division of Biostatistics (R.S.), Medical College of Wisconsin, and Zablocki Veterans Affairs Medical Center (D.D.G.), Milwaukee, WI
| | - Sheng Cao
- From the Department of Medicine (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Cardiovascular Center (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Department of Pharmacology and Toxicology (D.S.C., A.K.), Division of Biostatistics (R.S.), Medical College of Wisconsin, and Zablocki Veterans Affairs Medical Center (D.D.G.), Milwaukee, WI
| | - Dawid S Chabowski
- From the Department of Medicine (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Cardiovascular Center (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Department of Pharmacology and Toxicology (D.S.C., A.K.), Division of Biostatistics (R.S.), Medical College of Wisconsin, and Zablocki Veterans Affairs Medical Center (D.D.G.), Milwaukee, WI
| | - Ankush Korishettar
- From the Department of Medicine (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Cardiovascular Center (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Department of Pharmacology and Toxicology (D.S.C., A.K.), Division of Biostatistics (R.S.), Medical College of Wisconsin, and Zablocki Veterans Affairs Medical Center (D.D.G.), Milwaukee, WI
| | - Alyce Ge
- From the Department of Medicine (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Cardiovascular Center (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Department of Pharmacology and Toxicology (D.S.C., A.K.), Division of Biostatistics (R.S.), Medical College of Wisconsin, and Zablocki Veterans Affairs Medical Center (D.D.G.), Milwaukee, WI
| | - Xiaodong Zheng
- From the Department of Medicine (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Cardiovascular Center (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Department of Pharmacology and Toxicology (D.S.C., A.K.), Division of Biostatistics (R.S.), Medical College of Wisconsin, and Zablocki Veterans Affairs Medical Center (D.D.G.), Milwaukee, WI
| | - Rodney Sparapani
- From the Department of Medicine (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Cardiovascular Center (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Department of Pharmacology and Toxicology (D.S.C., A.K.), Division of Biostatistics (R.S.), Medical College of Wisconsin, and Zablocki Veterans Affairs Medical Center (D.D.G.), Milwaukee, WI
| | - David D Gutterman
- From the Department of Medicine (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Cardiovascular Center (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Department of Pharmacology and Toxicology (D.S.C., A.K.), Division of Biostatistics (R.S.), Medical College of Wisconsin, and Zablocki Veterans Affairs Medical Center (D.D.G.), Milwaukee, WI
| | - David X Zhang
- From the Department of Medicine (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Cardiovascular Center (Y.N., S.C., D.S.C., A.K., A.G., X.Z., D.D.G., D.X.Z.), Department of Pharmacology and Toxicology (D.S.C., A.K.), Division of Biostatistics (R.S.), Medical College of Wisconsin, and Zablocki Veterans Affairs Medical Center (D.D.G.), Milwaukee, WI.
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16
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Stott JB, Barrese V, Greenwood IA. Kv7 Channel Activation Underpins EPAC-Dependent Relaxations of Rat Arteries. Arterioscler Thromb Vasc Biol 2016; 36:2404-2411. [PMID: 27789473 DOI: 10.1161/atvbaha.116.308517] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/11/2016] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To establish the role of Kv7 channels in EPAC (exchange protein directly activated by cAMP)-dependent relaxations of the rat vasculature and to investigate whether this contributes to β-adrenoceptor-mediated vasorelaxations. APPROACH AND RESULTS Isolated rat renal and mesenteric arteries (RA and MA, respectively) were used for isometric tension recording to study the relaxant effects of a specific EPAC activator and the β-adrenoceptor agonist isoproterenol in the presence of potassium channel inhibitors and cell signaling modulators. Isolated myocytes were used in proximity ligation assay studies to detect localization of signaling intermediaries with Kv7.4 before and after cell stimulation. Our studies showed that the EPAC activator (8-pCPT-2Me-cAMP-AM) produced relaxations and enhanced currents of MA and RA that were sensitive to linopirdine (Kv7 inhibitor). Linopirdine also inhibited isoproterenol-mediated relaxations in both RA and MA. In the MA, isoproterenol relaxations were sensitive to EPAC inhibition, but not protein kinase A inhibition. In contrast, isoproterenol relaxations in RA were attenuated by protein kinase A but not by EPAC inhibition. Proximity ligation assay showed a localization of Kv7.4 with A-kinase anchoring protein in both vessels in the basal state, which increased only in the RA with isoproterenol stimulation. In the MA, but not the RA, a localization of Kv7.4 with both Rap1a and Rap2 (downstream of EPAC) increased with isoproterenol stimulation. CONCLUSIONS EPAC-dependent vasorelaxations occur in part via activation of Kv7 channels. This contributes to the isoproterenol-mediated relaxation in mesenteric, but not renal, arteries.
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Affiliation(s)
- Jennifer B Stott
- From the Vascular Biology Research Group, Institute for Cardiovascular and Cell Sciences, St George's University of London, UK
| | - Vincenzo Barrese
- From the Vascular Biology Research Group, Institute for Cardiovascular and Cell Sciences, St George's University of London, UK
| | - Iain A Greenwood
- From the Vascular Biology Research Group, Institute for Cardiovascular and Cell Sciences, St George's University of London, UK.
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17
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Critical contribution of KV1 channels to the regulation of coronary blood flow. Basic Res Cardiol 2016; 111:56. [PMID: 27496159 DOI: 10.1007/s00395-016-0575-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 07/08/2016] [Accepted: 08/02/2016] [Indexed: 12/11/2022]
Abstract
Ion channels in smooth muscle control coronary vascular tone, but the identity of the potassium channels involved requires further investigation. The purpose of this study was to evaluate the functional role of KV1 channels on porcine coronary blood flow using the selective antagonist correolide. KV1 channel gene transcripts were found in porcine coronary arteries, with KCNA5 (encoding KV1.5) being most abundant (P < 0.001). Immunohistochemical staining demonstrated KV1.5 protein in the vascular smooth muscle layer of both porcine and human coronary arteries, including microvessels. Whole-cell patch-clamp experiments demonstrated significant correolide-sensitive (1-10 µM) current in coronary smooth muscle. In vivo studies included direct intracoronary infusion of vehicle or correolide into a pressure-clamped left anterior descending artery of healthy swine (n = 5 in each group) with simultaneous measurement of coronary blood flow. Intracoronary correolide (~0.3-3 µM targeted plasma concentration) had no effect on heart rate or systemic pressure, but reduced coronary blood flow in a dose-dependent manner (P < 0.05). Dobutamine (0.3-10 µg/kg/min) elicited coronary metabolic vasodilation and intracoronary correolide (3 µM) significantly reduced coronary blood flow at any given level of myocardial oxygen consumption (P < 0.001). Coronary artery occlusions (15 s) elicited reactive hyperemia and correolide (3 µM) reduced the flow volume repayment by approximately 30 % (P < 0.05). Taken together, these data support a major role for KV1 channels in modulating baseline coronary vascular tone and, perhaps, vasodilation in response to increased metabolism and transient ischemia.
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