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Guo J, Zhang C, Zhao H, Yan Y, Liu Z. The key mediator of diabetic kidney disease: Potassium channel dysfunction. Genes Dis 2024; 11:101119. [PMID: 38523672 PMCID: PMC10958065 DOI: 10.1016/j.gendis.2023.101119] [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: 09/14/2021] [Revised: 06/11/2022] [Accepted: 06/04/2023] [Indexed: 03/26/2024] Open
Abstract
Diabetic kidney disease is a leading cause of end-stage renal disease, making it a global public health concern. The molecular mechanisms underlying diabetic kidney disease have not been elucidated due to its complex pathogenesis. Thus, exploring these mechanisms from new perspectives is the current focus of research concerning diabetic kidney disease. Ion channels are important proteins that maintain the physiological functions of cells and organs. Among ion channels, potassium channels stand out, because they are the most common and important channels on eukaryotic cell surfaces and function as the basis for cell excitability. Certain potassium channel abnormalities have been found to be closely related to diabetic kidney disease progression and genetic susceptibility, such as KATP, KCa, Kir, and KV. In this review, we summarized the roles of different types of potassium channels in the occurrence and development of diabetic kidney disease to discuss whether the development of DKD is due to potassium channel dysfunction and present new ideas for the treatment of DKD.
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Affiliation(s)
- Jia Guo
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Chaojie Zhang
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Hui Zhao
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Yufan Yan
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
| | - Zhangsuo Liu
- Nephrology Research Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, Henan 450052, China
- Research Center for Kidney Disease, Zhengzhou, Henan 450052, China
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2
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Echeverría F, Gonzalez-Sanabria N, Alvarado-Sanchez R, Fernández M, Castillo K, Latorre R. Large conductance voltage-and calcium-activated K + (BK) channel in health and disease. Front Pharmacol 2024; 15:1373507. [PMID: 38584598 PMCID: PMC10995336 DOI: 10.3389/fphar.2024.1373507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/12/2024] [Indexed: 04/09/2024] Open
Abstract
Large Conductance Voltage- and Calcium-activated K+ (BK) channels are transmembrane pore-forming proteins that regulate cell excitability and are also expressed in non-excitable cells. They play a role in regulating vascular tone, neuronal excitability, neurotransmitter release, and muscle contraction. Dysfunction of the BK channel can lead to arterial hypertension, hearing disorders, epilepsy, and ataxia. Here, we provide an overview of BK channel functioning and the implications of its abnormal functioning in various diseases. Understanding the function of BK channels is crucial for comprehending the mechanisms involved in regulating vital physiological processes, both in normal and pathological conditions, controlled by BK. This understanding may lead to the development of therapeutic interventions to address BK channelopathies.
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Affiliation(s)
- Felipe Echeverría
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Naileth Gonzalez-Sanabria
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Rosangelina Alvarado-Sanchez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Miguel Fernández
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Karen Castillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Investigación de Estudios Avanzados del Maule, Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca, Chile
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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3
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Van NTH, Kim WK, Nam JH. Challenges in the Therapeutic Targeting of KCa Channels: From Basic Physiology to Clinical Applications. Int J Mol Sci 2024; 25:2965. [PMID: 38474212 PMCID: PMC10932353 DOI: 10.3390/ijms25052965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 03/14/2024] Open
Abstract
Calcium-activated potassium (KCa) channels are ubiquitously expressed throughout the body and are able to regulate membrane potential and intracellular calcium concentrations, thereby playing key roles in cellular physiology and signal transmission. Consequently, it is unsurprising that KCa channels have been implicated in various diseases, making them potential targets for pharmaceutical interventions. Over the past two decades, numerous studies have been conducted to develop KCa channel-targeting drugs, including those for disorders of the central and peripheral nervous, cardiovascular, and urinary systems and for cancer. In this review, we synthesize recent findings regarding the structure and activating mechanisms of KCa channels. We also discuss the role of KCa channel modulators in therapeutic medicine. Finally, we identify the major reasons behind the delay in bringing these modulators to the pharmaceutical market and propose new strategies to promote their application.
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Affiliation(s)
- Nhung Thi Hong Van
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
| | - Woo Kyung Kim
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
- Department of Internal Medicine, Graduate School of Medicine, Dongguk University, Goyang 10326, Republic of Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
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4
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Staruschenko A, Ma R, Palygin O, Dryer SE. Ion channels and channelopathies in glomeruli. Physiol Rev 2023; 103:787-854. [PMID: 36007181 PMCID: PMC9662803 DOI: 10.1152/physrev.00013.2022] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/15/2022] [Accepted: 08/21/2022] [Indexed: 11/22/2022] Open
Abstract
An essential step in renal function entails the formation of an ultrafiltrate that is delivered to the renal tubules for subsequent processing. This process, known as glomerular filtration, is controlled by intrinsic regulatory systems and by paracrine, neuronal, and endocrine signals that converge onto glomerular cells. In addition, the characteristics of glomerular fluid flow, such as the glomerular filtration rate and the glomerular filtration fraction, play an important role in determining blood flow to the rest of the kidney. Consequently, disease processes that initially affect glomeruli are the most likely to lead to end-stage kidney failure. The cells that comprise the glomerular filter, especially podocytes and mesangial cells, express many different types of ion channels that regulate intrinsic aspects of cell function and cellular responses to the local environment, such as changes in glomerular capillary pressure. Dysregulation of glomerular ion channels, such as changes in TRPC6, can lead to devastating glomerular diseases, and a number of channels, including TRPC6, TRPC5, and various ionotropic receptors, are promising targets for drug development. This review discusses glomerular structure and glomerular disease processes. It also describes the types of plasma membrane ion channels that have been identified in glomerular cells, the physiological and pathophysiological contexts in which they operate, and the pathways by which they are regulated and dysregulated. The contributions of these channels to glomerular disease processes, such as focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy, as well as the development of drugs that target these channels are also discussed.
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Affiliation(s)
- Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida
- Hypertension and Kidney Research Center, University of South Florida, Tampa, Florida
- James A. Haley Veterans Hospital, Tampa, Florida
| | - Rong Ma
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Oleg Palygin
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Stuart E Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, Texas
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Liu XY, Qian LL, Wang RX. Hydrogen Sulfide-Induced Vasodilation: The Involvement of Vascular Potassium Channels. Front Pharmacol 2022; 13:911704. [PMID: 35721210 PMCID: PMC9198332 DOI: 10.3389/fphar.2022.911704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 05/02/2022] [Indexed: 12/21/2022] Open
Abstract
Hydrogen sulfide (H2S) has been highlighted as an important gasotransmitter in mammals. A growing number of studies have indicated that H2S plays a key role in the pathophysiology of vascular diseases and physiological vascular homeostasis. Alteration in H2S biogenesis has been reported in a variety of vascular diseases and H2S supplementation exerts effects of vasodilation. Accumulating evidence has shown vascular potassium channels activation is involved in H2S-induced vasodilation. This review aimed to summarize and discuss the role of H2S in the regulation of vascular tone, especially by interaction with different vascular potassium channels and the underlying mechanisms.
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Affiliation(s)
- Xiao-Yu Liu
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, China
| | - Ling-Ling Qian
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, China
| | - Ru-Xing Wang
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, China
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6
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Metabolic regulation and dysregulation of endothelial small conductance calcium activated potassium channels. Eur J Cell Biol 2022; 101:151208. [DOI: 10.1016/j.ejcb.2022.151208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/13/2022] Open
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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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8
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Neonatal Diabetes in Patients Affected by Liang-Wang Syndrome Carrying KCNMA1 Variant p.(Gly375Arg) Suggest a Potential Role of Ca 2+ and Voltage-Activated K + Channel Activity in Human Insulin Secretion. Curr Issues Mol Biol 2021; 43:1036-1042. [PMID: 34563042 PMCID: PMC8928946 DOI: 10.3390/cimb43020073] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/21/2021] [Accepted: 08/23/2021] [Indexed: 12/22/2022] Open
Abstract
Liang-Wang syndrome (LIWAS) is a polymalformative syndrome first described in 2019 caused by heterozygous mutation of the KCNMA1 gene encoding the Ca2+ and voltage-activated K+ channel (BKC). The KCNMA1 variant p.(Gly356Arg) abolishes the function of BKC and blocks the generation of K+ current. The phenotype of this variant includes developmental delay, and visceral and connective tissue malformations. So far, only three cases of LWAS have been described, one of which also had neonatal diabetes (ND). We present the case of a newborn affected by LIWAS carrying the p.(Gly375Arg) variant who manifested diabetes in the first week of life. The description of our case strongly increases the frequency of ND in LIWAS patients and suggests a role of BK inactivation in human insulin secretion. The knowledge on the role of BKC in insulin secretion is very poor. Analyzing the possible mechanisms that could explain the association of LIWAS with ND, we speculate that BK inactivation might impair insulin secretion through the alteration of ion-dependent membrane activities and mitochondrial functions in β-cells, as well as the impaired intra-islet vessel reactivity.
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9
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Minor Allele Frequencies and Molecular Pathways Differences for SNPs Associated with Amyotrophic Lateral Sclerosis in Subjects Participating in the UKBB and 1000 Genomes Project. J Clin Med 2021; 10:jcm10153394. [PMID: 34362180 PMCID: PMC8348602 DOI: 10.3390/jcm10153394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/12/2021] [Accepted: 07/28/2021] [Indexed: 12/25/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a complex disease with a late onset and is characterized by the progressive loss of muscular and respiratory functions. Although recent studies have partially elucidated ALS's mechanisms, many questions remain such as what the most important molecular pathways involved in ALS are and why there is such a large difference in ALS onset among different populations. In this study, we addressed this issue with a bioinformatics approach, using the United Kingdom Biobank (UKBB) and the European 1000 Genomes Project (1KG) in order to analyze the most ALS-representative single nucleotide polymorphisms (SNPs) that differ for minor allele frequency (MAF) between the United Kingdom population and some European populations including Finnish in Finland, Iberian population in Spain, and Tuscans in Italy. We found 84 SNPs associated with 46 genes that are involved in different pathways including: "Ca2+ activated K+ channels", "cGMP effects", "Nitric oxide stimulates guanylate cyclase", "Proton/oligopeptide cotransporters", and "Signaling by MAPK mutants". In addition, we revealed that 83% of the 84 SNPs can alter transcription factor-motives binding sites of 224 genes implicated in "Regulation of beta-cell development", "Transcription-al regulation by RUNX3", "Transcriptional regulation of pluripotent stem cells", and "FOXO-mediated transcription of cell death genes". In conclusion, the genes and pathways analyzed could explain the cause of the difference of ALS onset.
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He C, Li X, Wang M, Zhang S, Liu H. Deletion of BK channels decreased skeletal and cardiac muscle function but increased smooth muscle contraction in rats. Biochem Biophys Res Commun 2021; 570:8-14. [PMID: 34271438 DOI: 10.1016/j.bbrc.2021.07.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/07/2021] [Indexed: 12/28/2022]
Abstract
Large conductance calcium-activated potassium channel (BK channel) is widely expressed in skeletal muscle, myocardium, smooth muscle and other muscle tissues. Mutation, abnormal expression and altered activity of BK channel are linked to muscle-related diseases such as dyskinesia, epilepsy and erectile dysfunction. In order to compare the effects of BK channel on different muscle tissues, we constructed BK channel gene knockout rats (BK-/- rats). HE staining, open field and grip strength tests, ultrasound, blood pressure measurement and vascular tension test were utilized to explore the effects of BK channel deletion on the structure and function changes in skeletal muscle, myocardium, and vascular smooth muscle (VSM). It was found that compared with wild-type rats, the BK-/- rats showed decreased skeletal muscle fiber area, grip, movement distance and speed at 2 and 12 months of ages. At heart, the muscle fiber area, cardiac systolic/diastolic function and heart rate decreased in BK-/- rats. The wall of the left ventricle became thin. However, the vascular wall of BK-/- rats thickened, the pulse wave velocity was increased, and the VSM contraction was enhanced. Unexpectedly, both systolic and diastolic blood pressure were reduced in BK-/- rats, while pulse pressure difference was increased. These results suggest that BK channel may have different effects on different types of muscle tissue, and it should be noted that different parts of muscle tissue may have different effects when BK channel-related drugs are used.
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Affiliation(s)
- Chunyu He
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Beijing, 100069, China
| | - Xiaoyue Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Beijing, 100069, China
| | - Meili Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Beijing, 100069, China
| | - Suli Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Beijing, 100069, China.
| | - Huirong Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Disease, Beijing, 100069, China.
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11
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Granados ST, Latorre R, Torres YP. The Membrane Cholesterol Modulates the Interaction Between 17-βEstradiol and the BK Channel. Front Pharmacol 2021; 12:687360. [PMID: 34177597 PMCID: PMC8226216 DOI: 10.3389/fphar.2021.687360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/24/2021] [Indexed: 11/13/2022] Open
Abstract
BK channels are composed by the pore forming α subunit and, in some tissues, is associated with different accessory β subunits. These proteins modify the biophysical properties of the channel, amplifying the range of BK channel activation according to the physiological context. In the vascular cells, the pore forming BKα subunit is expressed with the β1 subunit, where they play an essential role in the modulation of arterial tone and blood pressure. In eukaryotes, cholesterol is a structural lipid of the cellular membrane. Changes in the ratio of cholesterol content in the plasma membrane (PM) regulates the BK channel activation altering its open probability, and hence, vascular contraction. It has been shown that the estrogen 17β-Estradiol (E2) causes a vasodilator effect in vascular cells, inducing a leftward shift in the V0.5 of the GV curve. Here, we evaluate whether changes in the membrane cholesterol concentration modify the effect that E2 induces on the BKα/β1 channel activity. Using binding and electrophysiology assays after cholesterol depletion or enrichment, we show that the cholesterol enrichment significantly decreases the expression of the α subunit, while cholesterol depletion increased the expression of that α subunit. Additionally, we demonstrated that changes in the membrane cholesterol cause the loss of the modulatory effect of E2 on the BKα/β1 channel activity, without affecting the E2 binding to the complex. Our data suggest that changes in membrane cholesterol content could affect channel properties related to the E2 effect on BKα/β1 channel activity. Finally, the results suggest that an optimal membrane cholesterol content is essential for the activation of BK channels through the β1 subunit.
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Affiliation(s)
- Sara T Granados
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia.,Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Yolima P Torres
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia
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Lee N, Lim BH, Lee KS, Shin J, Pagire HS, Pagire SH, Ahn JH, Lee SW, Kang TM, Park CS. Identification and Characterization of a Novel Large-Conductance Calcium-Activated Potassium Channel Activator, CTIBD, and Its Relaxation Effect on Urinary Bladder Smooth Muscle. Mol Pharmacol 2020; 99:114-124. [PMID: 33268552 DOI: 10.1124/molpharm.120.000106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 11/11/2020] [Indexed: 12/14/2022] Open
Abstract
The large-conductance calcium-activated potassium channel (BKCa channel) is expressed on various tissues and is involved in smooth muscle relaxation. The channel is highly expressed on urinary bladder smooth muscle cells and regulates the repolarization phase of the spontaneous action potentials that control muscle contraction. To discover novel chemical activators of the BKCa channel, we screened a chemical library containing 8364 chemical compounds using a cell-based fluorescence assay. A chemical compound containing an isoxazolyl benzene skeleton (compound 1) was identified as a potent activator of the BKCa channel and was structurally optimized through a structure-activity relationship study to obtain 4-(4-(4-chlorophenyl)-3-(trifluoromethyl)isoxazol-5-yl)benzene-1,3-diol (CTIBD). When CTIBD was applied to the treated extracellular side of the channel, the conductance-voltage relationship of the channel shifted toward a negative value, and the maximum conductance increased in a concentration-dependent manner. CTIBD altered the gating kinetics of the channel by dramatically slowing channel closing without effecting channel opening. The effects of CTIBD on bladder muscle relaxation and micturition function were tested in rat tissue and in vivo. CTIBD concentration-dependently reduced acetylcholine-induced contraction of urinary bladder smooth muscle strips. In an acetic acid-induced overactive bladder (OAB) model, intraperitoneal injection of 20 mg/kg CTIBD effectively restored frequent voiding contraction and lowered voiding volume without affecting other bladder function parameters. Thus, our results indicate that CTIBD and its derivatives are novel chemical activators of the bladder BKCa channel and potential candidates for OAB therapeutics. SIGNIFICANCE STATEMENT: The novel BKCa channel activator CTIBD was identified and characterized in this study. CTIBD directly activates the BKCa channel and relaxes urinary bladder smooth muscle of rat, so CTIBD can be a potential candidate for overactive bladder therapeutics.
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Affiliation(s)
- Narasaem Lee
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Bong Hee Lim
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Kyu-Sung Lee
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Jimin Shin
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Haushabhau S Pagire
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Suvarna H Pagire
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Jin Hee Ahn
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Sung Won Lee
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Tong Mook Kang
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Chul-Seung Park
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
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13
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Abstract
Ca2+- and voltage-gated K+ channels of large conductance (BK channels) are expressed in a diverse variety of both excitable and inexcitable cells, with functional properties presumably uniquely calibrated for the cells in which they are found. Although some diversity in BK channel function, localization, and regulation apparently arises from cell-specific alternative splice variants of the single pore-forming α subunit ( KCa1.1, Kcnma1, Slo1) gene, two families of regulatory subunits, β and γ, define BK channels that span a diverse range of functional properties. We are just beginning to unravel the cell-specific, physiological roles served by BK channels of different subunit composition.
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Affiliation(s)
- Vivian Gonzalez-Perez
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA;
| | - Christopher J Lingle
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA;
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14
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Perkins LA, Bruchez MP. Fluorogen activating protein toolset for protein trafficking measurements. Traffic 2020; 21:333-348. [PMID: 32080949 PMCID: PMC7462100 DOI: 10.1111/tra.12722] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/11/2022]
Abstract
Throughout the past decade the use of fluorogen activating proteins (FAPs) has expanded with several unique reporter dyes that support a variety of methods to specifically quantify protein trafficking events. The platform's capabilities have been demonstrated in several systems and shared for widespread use. This review will highlight the current FAP labeling techniques for protein traffic measurements and focus on the use of the different designed fluorogenic dyes for selective and specific labeling applications.
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Affiliation(s)
- Lydia A. Perkins
- School of MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Marcel P. Bruchez
- The Department of Biological SciencesCarnegie MellonPittsburghPennsylvaniaUSA
- Department of ChemistryCarnegie MellonPittsburghPennsylvaniaUSA
- Molecular and Biosensor Imaging CenterCarnegie MellonPittsburghPennsylvaniaUSA
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15
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Lan SH, Lai WT, Zheng SY, Yang L, Fang LC, Zhou L, Tang B, Duan J, Hong T. Upregulation of Connexin 40 Mediated by Nitric Oxide Attenuates Cerebral Vasospasm After Subarachnoid Hemorrhage via the Nitric Oxide-Cyclic Guanosine Monophosphate-Protein Kinase G Pathway. World Neurosurg 2020; 136:e476-e486. [PMID: 31953101 DOI: 10.1016/j.wneu.2020.01.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 01/07/2023]
Abstract
OBJECTIVE The present study was performed to elucidate the role of nitric oxide (NO) and connexin 40 (Cx40) in the induction of cerebral vasospasm after subarachnoid hemorrhage (SAH) in vivo. METHODS A SAH rat model was established using the double-bleed method. A total of 108 Sprague-Dawley rats weighing 250-300 g were randomly divided into 6 groups: SAH; SAH plus diethylenetriamine (DETA)/NO (exogenous NO donor); SAH plus 8-bromoadenosine (8-Br)-cyclic guanosine monophosphate (cGMP; protein kinase G [PKG] activator); SAH plus DETA/NO plus KT5823 (PKG inhibitor); SAH plus DETA/NO plus 40Gap27 (Cx40 inhibitor); and sham. The changes in the diameter of the branch microvessels in the middle cerebral artery were recorded. The neurological score was evaluated using the Garcia scoring system. Basilar artery (BA) tension was measured using the Danish Myo Technology myograph system. Cx40 protein expression was analyzed using immunofluorescence and Western blotting. Endothelial NO synthase, soluble guanylate cyclase, and PKG protein expression were measured by Western blotting. RESULTS A considerable narrowing of the cerebral vessels was detected in the SAH group compared with that in the sham group. Moreover, compared with the sham group, the SAH group showed a marked decrease in Cx40, endothelial NO synthase, soluble guanylate cyclase, and PKG expression. The expression of Cx40 and PKG were obviously higher in the SAH plus DETA/NO and SAH plus 8-Br-cGMP groups than in the SAH group. However, Cx40 was lower in the SAH plus DETA/NO plus KT5823 and SAH plus DETA/NO plus 40Gap27 groups than in the SAH plus ETA/NO group. The BAs showed significant vasodilation in the SAH plus DETA/NO and SAH plus 8-Br-cGMP groups. However, the vasodilation response of BAs was inhibited in the SAH plus DETA/NO plus KT5823 and SAH plus DETA-NO plus 40Gap27 groups. CONCLUSIONS The NO-cGMP-PKG pathway alleviated cerebral vasospasm via Cx40 upregulation.
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Affiliation(s)
- Shi Hai Lan
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Wen Tao Lai
- Department of Neurosurgery, Affiliated Ganzhou Hospital of Nanchang University, Ganzhou, China
| | - Su Yue Zheng
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Le Yang
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Lin Chun Fang
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Lin Zhou
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Bin Tang
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jian Duan
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Tao Hong
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China.
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16
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Manoury B, Idres S, Leblais V, Fischmeister R. Ion channels as effectors of cyclic nucleotide pathways: Functional relevance for arterial tone regulation. Pharmacol Ther 2020; 209:107499. [PMID: 32068004 DOI: 10.1016/j.pharmthera.2020.107499] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 02/05/2020] [Indexed: 02/07/2023]
Abstract
Numerous mediators and drugs regulate blood flow or arterial pressure by acting on vascular tone, involving cyclic nucleotide intracellular pathways. These signals lead to regulation of several cellular effectors, including ion channels that tune cell membrane potential, Ca2+ influx and vascular tone. The characterization of these vasocontrictive or vasodilating mechanisms has grown in complexity due to i) the variety of ion channels that are expressed in both vascular endothelial and smooth muscle cells, ii) the heterogeneity of responses among the various vascular beds, and iii) the number of molecular mechanisms involved in cyclic nucleotide signalling in health and disease. This review synthesizes key data from literature that highlight ion channels as physiologically relevant effectors of cyclic nucleotide pathways in the vasculature, including the characterization of the molecular mechanisms involved. In smooth muscle cells, cation influx or chloride efflux through ion channels are associated with vasoconstriction, whereas K+ efflux repolarizes the cell membrane potential and mediates vasodilatation. Both categories of ion currents are under the influence of cAMP and cGMP pathways. Evidence that some ion channels are influenced by CN signalling in endothelial cells will also be presented. Emphasis will also be put on recent data touching a variety of determinants such as phosphodiesterases, EPAC and kinase anchoring, that complicate or even challenge former paradigms.
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Affiliation(s)
- Boris Manoury
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France.
| | - Sarah Idres
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
| | - Véronique Leblais
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
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17
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Tao X, MacKinnon R. Molecular structures of the human Slo1 K + channel in complex with β4. eLife 2019; 8:51409. [PMID: 31815672 PMCID: PMC6934384 DOI: 10.7554/elife.51409] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/06/2019] [Indexed: 12/16/2022] Open
Abstract
Slo1 is a Ca2+- and voltage-activated K+ channel that underlies skeletal and smooth muscle contraction, audition, hormone secretion and neurotransmitter release. In mammals, Slo1 is regulated by auxiliary proteins that confer tissue-specific gating and pharmacological properties. This study presents cryo-EM structures of Slo1 in complex with the auxiliary protein, β4. Four β4, each containing two transmembrane helices, encircle Slo1, contacting it through helical interactions inside the membrane. On the extracellular side, β4 forms a tetrameric crown over the pore. Structures with high and low Ca2+ concentrations show that identical gating conformations occur in the absence and presence of β4, implying that β4 serves to modulate the relative stabilities of 'pre-existing' conformations rather than creating new ones. The effects of β4 on scorpion toxin inhibition kinetics are explained by the crown, which constrains access but does not prevent binding.
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Affiliation(s)
- Xiao Tao
- Laboratory of Molecular Neurobiology and Biophysics, The Rockefeller University, Howard Hughes Medical Institute, New York, United States
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, The Rockefeller University, Howard Hughes Medical Institute, New York, United States
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18
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Galíndez-Cerón JD, Jorge RJB, Chavez-Acosta MH, Jorge ARC, Alves NTQ, Prata MMG, Rodrigues FADP, Havt A, Sampaio TL, Martins AMC, Guerrero-Vargas JA, Monteiro HSA, Beltrán-Vidal JT. Renal Alterations Induced by the Venom of Colombian Scorpion Centruroides Margaritatus. Curr Top Med Chem 2019; 19:2049-2057. [PMID: 31364515 DOI: 10.2174/1568026619666190731143523] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/21/2019] [Accepted: 06/05/2019] [Indexed: 12/25/2022]
Abstract
BACKGROUND Scorpion venom causes renal injury and affects vascular ion-channels function. Centruroides margaritatus scorpion is found in Colombia and is frequently the cause of envenomation accidents; however, its renal impact has never been investigated. OBJECTIVE To evaluate the effects of C. margaritatus venom (CmV) on renal parameters using isolated rat kidney and renal cell culture models. METHODS Wistar rats (n = 5, weighing 240-300 g) were first perfused with Krebs-Henseleit solution containing 6 g 100 mL-1 bovine serum albumin. After 30 minutes, the kidneys were perfused with CmV to a final concentration of 10 μgmL-1; evaluation was performed by measuring Perfusion Pressure (PP), Renal Vascular Resistance (RVR), Urinary Flow (UF), Glomerular Filtration Rate (GFR), and percentage of electrolyte tubular transport. Moreover, kidney histological analyses and cell cytotoxicity in renal tubule epithelial cells (MDCK) and proximal tubular cells (LLC-MK2) were assessed. RESULTS CmV increased PP and RVR 60 min after perfusion. On the other hand, UF, GFR, and the percentages of sodium, potassium and chloride tubular transport decreased after experimental envenomation. UF dropped after 120 min, while GFR and percentage of electrolyte tubular transport diminished after 60, 90 and 120 min. CmV was not toxic to MDCK cell line but reduced the viability of LLC-MK2 cells at concentrations ranging from 6.25 to 200 μgmL-1. Histological analyses disclosed hydropic degeneration, edema, and protein deposits. Flow cytometry disclosed that cell death occurred predominantly by necrosis. CONCLUSION Our results suggest that C. margaritatus venom can trigger renal impairment, mainly in the proximal kidney tubule.
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Affiliation(s)
- J D Galíndez-Cerón
- Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Grupo de Investigaciones Herpetológicas y Toxinológicas, Universidad del Cauca, Popayán, Colombia
| | - R J B Jorge
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - M H Chavez-Acosta
- Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Grupo de Investigaciones Herpetológicas y Toxinológicas, Universidad del Cauca, Popayán, Colombia
| | - A R C Jorge
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - N T Q Alves
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - M M G Prata
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - F A de Paulo Rodrigues
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - A Havt
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - T L Sampaio
- Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - A M C Martins
- Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - J A Guerrero-Vargas
- Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Grupo de Investigaciones Herpetológicas y Toxinológicas, Universidad del Cauca, Popayán, Colombia
| | - H S A Monteiro
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - J T Beltrán-Vidal
- Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Grupo de Investigaciones Herpetológicas y Toxinológicas, Universidad del Cauca, Popayán, Colombia
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19
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Iguchi N, Dönmez Mİ, Carrasco A, Wilcox DT, Pineda RH, Malykhina AP, Cost NG. Doxorubicin induces detrusor smooth muscle impairments through myosin dysregulation, leading to a risk of lower urinary tract dysfunction. Am J Physiol Renal Physiol 2019; 317:F197-F206. [PMID: 31066574 DOI: 10.1152/ajprenal.00090.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cytotoxic chemotherapy is the foundation for the treatment of the wide variety of childhood malignancies; however, these therapies are known to have a variety of deleterious side effects. One common chemotherapy used in children, doxorubicin (DOX), is well known to cause cardiotoxicity and cardiomyopathy. Recent studies have revealed that DOX impairs skeletal and smooth muscle function and contributes to fatigue and abnormal intestinal motility in patients. In this study, we tested the hypothesis that systemic DOX administration also affects detrusor smooth muscle (DSM) function in the urinary bladder, especially when administered at a young age. The effects on the DSM and bladder function were assessed in BALB/cJ mice that received six weekly intravenous injections of DOX (3 mg·kg-1·wk-1) or saline for the control group. Systemic DOX administration resulted in DSM hypertrophy, increased voiding frequency, and a significant attenuation of DSM contractility, followed by a slower relaxation compared with the control group. Gene expression analyses revealed that unlike DOX-induced cardiotoxicity, the bladders from DOX-administered animals showed no changes in oxidative stress markers; instead, downregulation of large-conductance Ca2+-activated K+ channels and altered expression of myosin light-chain kinase coincided with reduced myosin light-chain phosphorylation. These results indicate that in vivo DOX exposure caused DSM dysfunction by dysregulation of molecules involved in the detrusor contractile-relaxation mechanisms. Collectively, our findings suggest that survivors of childhood cancer treated with DOX may be at increased risk of bladder dysfunction and benefit from followup surveillance of bladder function.
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Affiliation(s)
- Nao Iguchi
- Division of Urology, Department of Surgery, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - M İrfan Dönmez
- Division of Urology, Department of Surgery, University of Colorado Denver School of Medicine , Aurora, Colorado.,Children's Hospital Colorado , Aurora, Colorado
| | - Alonso Carrasco
- Children's Hospital Colorado , Aurora, Colorado.,Children's Mercy Kansas City, Kansas City, Missouri
| | - Duncan T Wilcox
- Division of Urology, Department of Surgery, University of Colorado Denver School of Medicine , Aurora, Colorado.,Children's Hospital Colorado , Aurora, Colorado
| | - Ricardo H Pineda
- Division of Urology, Department of Surgery, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Anna P Malykhina
- Division of Urology, Department of Surgery, University of Colorado Denver School of Medicine , Aurora, Colorado
| | - Nicholas G Cost
- Division of Urology, Department of Surgery, University of Colorado Denver School of Medicine , Aurora, Colorado.,Children's Hospital Colorado , Aurora, Colorado
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20
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Tettey CO, Yang IJ, Shin HM. Vasodilatory effect of kaempferol-7-O-α-L-rhamnopyranoside via NO-cGMP-PKG signaling. Arch Biochem Biophys 2019; 667:1-5. [PMID: 30981710 DOI: 10.1016/j.abb.2019.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/19/2019] [Accepted: 04/10/2019] [Indexed: 01/18/2023]
Abstract
Hypertension is one of the major causes of mortality. Though a host of drugs are available for the treatment of hypertension, majority have been linked to adverse side effects, necessitating the need for research into natural compounds with fewer side effects. Kaempferol-7-O-α-L-rhamnopyroside (KR) is a glycosylated flavone with neuroprotective and anti-inflammatory effects. However, no available literature exists on its vasodilatory effect. This study examined the pharmacological effect of KR on vasodilation/vasorelaxation and its mechanism of action in endothelial cells and rat thoracic aorta. Treatment of phenylephrine (PE; 2 × 10-6 M)-pre-contracted aortic rings with KR induced endothelium-dependent relaxation, which was suppressed by NG-nitro-l-arginine methyl ester (L-NAME; 10-4 M), (nitric oxide synthase (NOS) inhibitor). Phosphorylation of eNOS in human umbilical vein endothelial cells (HUVECs) was increased after exposure to KR. Pre-treatment of aortic rings with the cyclic GMP (cGMP) inhibitors; methylene blue (MB; 10-5 M) and 1-H-[1,2,4]-oxadiazolole-[4,3-α]-quinoxalin-10-one, (ODQ; 10-6 M) suppressed the KR-induced vasodilation. Furthermore, KR also increased protein kinase G (PKG) levels whereas it suppressed levels of phosphorylated myosin light chain (MLC) and protein kinase C (PKC) in aortic rings. These results suggest that KR induces endothelium-dependent vasorelaxation via the NO-cGMP-PKG pathway.
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Affiliation(s)
- Clement O Tettey
- Department of Biomedical Sciences, University of Health and Allied Sciences, PMB 31, Ho, Ghana; Department of Physiology, College of Korean Medicine, Dongguk University, Gyeongju, South Korea
| | - In-Jun Yang
- Department of Physiology, College of Korean Medicine, Dongguk University, Gyeongju, South Korea
| | - Heung-Mook Shin
- Department of Physiology, College of Korean Medicine, Dongguk University, Gyeongju, South Korea; National Development Institute of Korean Medicine, Gyeongsan, Gyeongbuk, 712-210, South Korea.
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21
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Abstract
Ca2+- and voltage-gated K+ channels of large conductance (BK channels) are expressed in a diverse variety of both excitable and inexcitable cells, with functional properties presumably uniquely calibrated for the cells in which they are found. Although some diversity in BK channel function, localization, and regulation apparently arises from cell-specific alternative splice variants of the single pore-forming α subunit ( KCa1.1, Kcnma1, Slo1) gene, two families of regulatory subunits, β and γ, define BK channels that span a diverse range of functional properties. We are just beginning to unravel the cell-specific, physiological roles served by BK channels of different subunit composition.
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Affiliation(s)
- Vivian Gonzalez-Perez
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA;
| | - Christopher J Lingle
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA;
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22
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Idres S, Perrin G, Domergue V, Lefebvre F, Gomez S, Varin A, Fischmeister R, Leblais V, Manoury B. Contribution of BKCa channels to vascular tone regulation by PDE3 and PDE4 is lost in heart failure. Cardiovasc Res 2018; 115:130-144. [DOI: 10.1093/cvr/cvy161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 06/21/2018] [Indexed: 12/23/2022] Open
Abstract
Abstract
Aims
Regulation of vascular tone by 3′,5′-cyclic adenosine monophosphate (cAMP) involves many effectors including the large conductance, Ca2+-activated, K+ (BKCa) channels. In arteries, cAMP is mainly hydrolyzed by type 3 and 4 phosphodiesterases (PDE3, PDE4). Here, we examined the specific contribution of BKCa channels to tone regulation by these PDEs in rat coronary arteries, and how this is altered in heart failure (HF).
Methods and results
Concomitant application of PDE3 (cilostamide) and PDE4 (Ro-20-1724) inhibitors increased BKCa unitary channel activity in isolated myocytes from rat coronary arteries. Myography was conducted in isolated, U46619-contracted coronary arteries. Cilostamide (Cil) or Ro-20-1724 induced a vasorelaxation that was greatly reduced by iberiotoxin (IBTX), a BKCa channel blocker. Ro-20-1724 and Cil potentiated the relaxation induced by the β-adrenergic agonist isoprenaline (ISO) or the adenylyl cyclase activator L-858051 (L85). IBTX abolished the effect of PDE inhibitors on ISO but did not on L85. In coronary arteries from rats with HF induced by aortic stenosis, contractility and response to acetylcholine were dramatically reduced compared with arteries from sham rats, but relaxation to PDE inhibitors was retained. Interestingly, however, IBTX had no effect on Ro-20-1724- and Cil-induced vasorelaxations in HF. Expression of the BKCa channel α-subunit, of a 98 kDa PDE3A and of a 80 kDa PDE4D were lower in HF compared with sham coronary arteries, while that of a 70 kDa PDE4B was increased. Proximity ligation assays demonstrated that PDE3 and PDE4 were localized in the vicinity of the channel.
Conclusion
BKCa channels mediate the relaxation of coronary artery induced by PDE3 and PDE4 inhibition. This is achieved by co-localization of both PDEs with BKCa channels, enabling tight control of cAMP available for channel opening. Contribution of the channel is prominent at rest and on β-adrenergic stimulation. This coupling is lost in HF.
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Affiliation(s)
- Sarah Idres
- Signalling and Cardiovascular Pathophysiology—UMR-S 1180, Université Paris-Sud, INSERM, Université Paris-Saclay, 5 rue J-B Clément, Châtenay-Malabry, France
| | - Germain Perrin
- Signalling and Cardiovascular Pathophysiology—UMR-S 1180, Université Paris-Sud, INSERM, Université Paris-Saclay, 5 rue J-B Clément, Châtenay-Malabry, France
| | - Valérie Domergue
- UMS IPSIT, Université Paris-Sud, Université Paris-Saclay, 5 rue J-B Clément, Châtenay-Malabry, France
| | - Florence Lefebvre
- Signalling and Cardiovascular Pathophysiology—UMR-S 1180, Université Paris-Sud, INSERM, Université Paris-Saclay, 5 rue J-B Clément, Châtenay-Malabry, France
| | - Susana Gomez
- Signalling and Cardiovascular Pathophysiology—UMR-S 1180, Université Paris-Sud, INSERM, Université Paris-Saclay, 5 rue J-B Clément, Châtenay-Malabry, France
| | - Audrey Varin
- Signalling and Cardiovascular Pathophysiology—UMR-S 1180, Université Paris-Sud, INSERM, Université Paris-Saclay, 5 rue J-B Clément, Châtenay-Malabry, France
| | - Rodolphe Fischmeister
- Signalling and Cardiovascular Pathophysiology—UMR-S 1180, Université Paris-Sud, INSERM, Université Paris-Saclay, 5 rue J-B Clément, Châtenay-Malabry, France
| | - Véronique Leblais
- Signalling and Cardiovascular Pathophysiology—UMR-S 1180, Université Paris-Sud, INSERM, Université Paris-Saclay, 5 rue J-B Clément, Châtenay-Malabry, France
| | - Boris Manoury
- Signalling and Cardiovascular Pathophysiology—UMR-S 1180, Université Paris-Sud, INSERM, Université Paris-Saclay, 5 rue J-B Clément, Châtenay-Malabry, France
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23
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Sterea AM, Almasi S, El Hiani Y. The hidden potential of lysosomal ion channels: A new era of oncogenes. Cell Calcium 2018; 72:91-103. [PMID: 29748137 DOI: 10.1016/j.ceca.2018.02.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/28/2018] [Accepted: 02/28/2018] [Indexed: 01/14/2023]
Abstract
Lysosomes serve as the control centre for cellular clearance. These membrane-bound organelles receive biomolecules destined for degradation from intracellular and extracellular pathways; thus, facilitating the production of energy and shaping the fate of the cell. At the base of their functionality are the lysosomal ion channels which mediate the function of the lysosome through the modulation of ion influx and efflux. Ion channels form pores in the membrane of lysosomes and allow the passage of ions, a seemingly simple task which harbours the potential of overthrowing the cell's stability. Considered the master regulators of ion homeostasis, these integral membrane proteins enable the proper operation of the lysosome. Defects in the structure or function of these ion channels lead to the development of lysosomal storage diseases, neurodegenerative diseases and cancer. Although more than 50 years have passed since their discovery, lysosomes are not yet fully understood, with their ion channels being even less well characterized. However, significant improvements have been made in the development of drugs targeted against these ion channels as a means of combating diseases. In this review, we will examine how Ca2+, K+, Na+ and Cl- ion channels affect the function of the lysosome, their involvement in hereditary and spontaneous diseases, and current ion channel-based therapies.
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Affiliation(s)
- Andra M Sterea
- Departments of Physiology & Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Shekoufeh Almasi
- Departments of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Yassine El Hiani
- Departments of Physiology & Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.
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BKCa channel activity and vascular contractility alterations with hypertension and aging via β1 subunit promoter methylation in mesenteric arteries. Hypertens Res 2017; 41:96-103. [DOI: 10.1038/hr.2017.96] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/12/2017] [Accepted: 07/28/2017] [Indexed: 01/14/2023]
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25
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Wang L, He J, Xia A, Cheng M, Yang Q, Du C, Wei H, Huang X, Zhou Q. Toxic effects of environmental rare earth elements on delayed outward potassium channels and their mechanisms from a microscopic perspective. CHEMOSPHERE 2017; 181:690-698. [PMID: 28476009 DOI: 10.1016/j.chemosphere.2017.04.141] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 04/25/2017] [Accepted: 04/27/2017] [Indexed: 06/07/2023]
Abstract
The wide applications cause a large amount of rare earth elements (REEs) to be released into the environment, and ultimately into the human body through food chain. Toxic effects of REEs on humans have been extensively studied, but their toxic effects and binding targets in cells are not understood. Delayed outward potassium channels (K+ channels) are good targets for exogenous substances or clinical drugs. To evaluate cellular toxicities of REEs and clarify toxic mechanisms, the toxicities of REEs on the K+ channel and their structural basis were investigated. The results showed that delayed outward potassium channels on the plasma membrane are the targets of REEs acting on living organisms, and the changes in the thermodynamic and kinetic characteristics of the K+ channel are the reasons of diseases induced by REEs. Two types of REEs, a light REE La3+ and a heavy REE Tb3+, displayed different intensity of toxicities on the K+ channel, in which the toxicity of Tb3+ was stronger than that of La3+. More interestingly, in comparison with that of heavy metal Cd2+, the cytotoxicities of the light and heavy REEs showed discriminative differences, and the cytotoxicity of Tb3+ was higher than that of Cd2+, while the cytotoxicity of La3+ was lower than that of Cd2+. These different cytotoxicities of La3+, Tb3+ and Cd2+ on human resulted from the varying binding abilities of the metals to this channel protein.
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Affiliation(s)
- Lihong Wang
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China; State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Jingfang He
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China
| | - Ao Xia
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China
| | - Mengzhu Cheng
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China
| | - Qing Yang
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China
| | - Chunlei Du
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China
| | - Haiyan Wei
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China
| | - Xiaohua Huang
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China.
| | - Qing Zhou
- State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China.
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Zhai X, Leo MD, Jaggar JH. Endothelin-1 Stimulates Vasoconstriction Through Rab11A Serine 177 Phosphorylation. Circ Res 2017; 121:650-661. [PMID: 28696251 DOI: 10.1161/circresaha.117.311102] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 01/18/2023]
Abstract
RATIONALE Large-conductance calcium-activated potassium channels (BK) are composed of pore-forming BKα and auxiliary β1 subunits in arterial smooth muscle cells (myocytes). Vasoconstrictors, including endothelin-1 (ET-1), inhibit myocyte BK channels, leading to contraction, but mechanisms involved are unclear. Recent evidence indicates that BKα is primarily plasma membrane localized, whereas the cellular location of β1 can be rapidly altered by Rab11A-positive recycling endosomes. Whether vasoconstrictors regulate the multisubunit composition of surface BK channels to stimulate contraction is unclear. OBJECTIVE Test the hypothesis that ET-1 inhibits BK channels by altering BKα and β1 surface trafficking in myocytes, identify mechanisms involved, and determine functional significance in myocytes of small cerebral arteries. METHODS AND RESULTS ET-1, through activation of PKC (protein kinase C), reduced surface β1 abundance and the proximity of β1 to surface BKα in myocytes. In contrast, ET-1 did not alter surface BKα, total β1, or total BKα proteins. ET-1 stimulated Rab11A phosphorylation, which reduced Rab11A activity. Rab11A serine 177 was identified as a high-probability PKC phosphorylation site. Expression of a phosphorylation-incapable Rab11A construct (Rab11A S177A) blocked the ET-1-induced Rab11A phosphorylation, reduction in Rab11A activity, and decrease in surface β1 protein. ET-1 inhibited single BK channels and transient BK currents in myocytes and stimulated vasoconstriction via a PKC-dependent mechanism that required Rab11A S177. In contrast, NO-induced Rab11A activation, surface trafficking of β1 subunits, BK channel and transient BK current activation, and vasodilation did not involve Rab11A S177. CONCLUSIONS ET-1 stimulates PKC-mediated phosphorylation of Rab11A at serine 177, which inhibits Rab11A and Rab11A-dependent surface trafficking of β1 subunits. The decrease in surface β1 subunits leads to a reduction in BK channel calcium-sensitivity, inhibition of transient BK currents, and vasoconstriction. We describe a unique mechanism by which a vasoconstrictor inhibits BK channels and identify Rab11A serine 177 as a modulator of arterial contractility.
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Affiliation(s)
- Xue Zhai
- From the Department of Physiology, University of Tennessee Health Science Center, Memphis
| | - M Dennis Leo
- From the Department of Physiology, University of Tennessee Health Science Center, Memphis
| | - Jonathan H Jaggar
- From the Department of Physiology, University of Tennessee Health Science Center, Memphis.
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Leo MD, Zhai X, Muralidharan P, Kuruvilla KP, Bulley S, Boop FA, Jaggar JH. Membrane depolarization activates BK channels through ROCK-mediated β1 subunit surface trafficking to limit vasoconstriction. Sci Signal 2017; 10:10/478/eaah5417. [PMID: 28487419 DOI: 10.1126/scisignal.aah5417] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Membrane depolarization of smooth muscle cells (myocytes) in the small arteries that regulate regional organ blood flow leads to vasoconstriction. Membrane depolarization also activates large-conductance calcium (Ca2+)-activated potassium (BK) channels, which limits Ca2+ channel activity that promotes vasoconstriction, thus leading to vasodilation. We showed that in human and rat arterial myocytes, membrane depolarization rapidly increased the cell surface abundance of auxiliary BK β1 subunits but not that of the pore-forming BKα channels. Membrane depolarization stimulated voltage-dependent Ca2+ channels, leading to Ca2+ influx and the activation of Rho kinase (ROCK) 1 and 2. ROCK1/2-mediated activation of Rab11A promoted the delivery of β1 subunits to the plasma membrane by Rab11A-positive recycling endosomes. These additional β1 subunits associated with BKα channels already at the plasma membrane, leading to an increase in apparent Ca2+ sensitivity and activation of the channels in pressurized arterial myocytes and vasodilation. Thus, membrane depolarization activates BK channels through stimulation of ROCK- and Rab11A-dependent trafficking of β1 subunits to the surface of arterial myocytes.
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Affiliation(s)
- M Dennis Leo
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Xue Zhai
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Padmapriya Muralidharan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Korah P Kuruvilla
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Simon Bulley
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Frederick A Boop
- Department of Neurosurgery, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Jonathan H Jaggar
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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28
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Katsumata Y, Nelson PT, Ellingson SR, Fardo DW. Gene-based association study of genes linked to hippocampal sclerosis of aging neuropathology: GRN, TMEM106B, ABCC9, and KCNMB2. Neurobiol Aging 2017; 53:193.e17-193.e25. [PMID: 28131462 PMCID: PMC5385271 DOI: 10.1016/j.neurobiolaging.2017.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/29/2016] [Accepted: 01/03/2017] [Indexed: 12/12/2022]
Abstract
Hippocampal sclerosis of aging (HS-Aging) is a common neurodegenerative condition associated with dementia. To learn more about genetic risk of HS-Aging pathology, we tested gene-based associations of the GRN, TMEM106B, ABCC9, and KCNMB2 genes, which were reported to be associated with HS-Aging pathology in previous studies. Genetic data were obtained from the Alzheimer's Disease Genetics Consortium, linked to autopsy-derived neuropathological outcomes from the National Alzheimer's Coordinating Center. Of the 3251 subjects included in the study, 271 (8.3%) were identified as an HS-Aging case. The significant gene-based association between the ABCC9 gene and HS-Aging appeared to be driven by a region in which a significant haplotype-based association was found. We tested this haplotype as an expression quantitative trait locus using 2 different public-access brain gene expression databases. The HS-Aging pathology protective ABCC9 haplotype was associated with decreased ABCC9 expression, indicating a possible toxic gain of function.
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Affiliation(s)
- Yuriko Katsumata
- Department of Biostatistics, University of Kentucky, Lexington, KY, USA
| | - Peter T Nelson
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Pathology, University of Kentucky, Lexington, KY, USA
| | - Sally R Ellingson
- Division of Biomedical Informatics, University of Kentucky, Lexington, KY, USA
| | - David W Fardo
- Department of Biostatistics, University of Kentucky, Lexington, KY, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
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29
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Latorre R, Castillo K, Carrasquel-Ursulaez W, Sepulveda RV, Gonzalez-Nilo F, Gonzalez C, Alvarez O. Molecular Determinants of BK Channel Functional Diversity and Functioning. Physiol Rev 2017; 97:39-87. [DOI: 10.1152/physrev.00001.2016] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Large-conductance Ca2+- and voltage-activated K+ (BK) channels play many physiological roles ranging from the maintenance of smooth muscle tone to hearing and neurosecretion. BK channels are tetramers in which the pore-forming α subunit is coded by a single gene ( Slowpoke, KCNMA1). In this review, we first highlight the physiological importance of this ubiquitous channel, emphasizing the role that BK channels play in different channelopathies. We next discuss the modular nature of BK channel-forming protein, in which the different modules (the voltage sensor and the Ca2+ binding sites) communicate with the pore gates allosterically. In this regard, we review in detail the allosteric models proposed to explain channel activation and how the models are related to channel structure. Considering their extremely large conductance and unique selectivity to K+, we also offer an account of how these two apparently paradoxical characteristics can be understood consistently in unison, and what we have learned about the conduction system and the activation gates using ions, blockers, and toxins. Attention is paid here to the molecular nature of the voltage sensor and the Ca2+ binding sites that are located in a gating ring of known crystal structure and constituted by four COOH termini. Despite the fact that BK channels are coded by a single gene, diversity is obtained by means of alternative splicing and modulatory β and γ subunits. We finish this review by describing how the association of the α subunit with β or with γ subunits can change the BK channel phenotype and pharmacology.
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Affiliation(s)
- Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Karen Castillo
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Willy Carrasquel-Ursulaez
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Romina V. Sepulveda
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Fernando Gonzalez-Nilo
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Carlos Gonzalez
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Osvaldo Alvarez
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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Moreno C, de la Cruz A, Valenzuela C. In-Depth Study of the Interaction, Sensitivity, and Gating Modulation by PUFAs on K + Channels; Interaction and New Targets. Front Physiol 2016; 7:578. [PMID: 27933000 PMCID: PMC5121229 DOI: 10.3389/fphys.2016.00578] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/11/2016] [Indexed: 02/05/2023] Open
Abstract
Voltage gated potassium channels (KV) are membrane proteins that allow selective flow of K+ ions in a voltage-dependent manner. These channels play an important role in several excitable cells as neurons, cardiomyocytes, and vascular smooth muscle. Over the last 20 years, it has been shown that omega-3 polyunsaturated fatty acids (PUFAs) enhance or decrease the activity of several cardiac KV channels. PUFAs-dependent modulation of potassium ion channels has been reported to be cardioprotective. However, the precise cellular mechanism underlying the cardiovascular benefits remained unclear in part because new PUFAs targets and signaling pathways continue being discovered. In this review, we will focus on recent data available concerning the following aspects of the KV channel modulation by PUFAs: (i) the exact residues involved in PUFAs-KV channels interaction; (ii) the structural PUFAs determinants important for their effects on KV channels; (iii) the mechanism of the gating modulation of KV channels and, finally, (iv) the PUFAs modulation of a few new targets present in smooth muscle cells (SMC), KCa1.1, K2P, and KATP channels, involved in vascular relaxation.
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Affiliation(s)
- Cristina Moreno
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre Maastricht, Netherlands
| | - Alicia de la Cruz
- Departamento de Modelos Experimentales de Enfermedades Humanas, Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC - Universidad Autónoma de Madrid Madrid, Spain
| | - Carmen Valenzuela
- Departamento de Modelos Experimentales de Enfermedades Humanas, Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC - Universidad Autónoma de Madrid Madrid, Spain
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31
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Hei H, Gao J, Dong J, Tao J, Tian L, Pan W, Wang H, Zhang X. BK Knockout by TALEN-Mediated Gene Targeting in Osteoblasts: KCNMA1 Determines the Proliferation and Differentiation of Osteoblasts. Mol Cells 2016; 39:530-5. [PMID: 27329042 PMCID: PMC4959017 DOI: 10.14348/molcells.2016.0033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 05/21/2016] [Accepted: 05/23/2016] [Indexed: 11/27/2022] Open
Abstract
Large conductance calcium-activated potassium (BK) channels participate in many important physiological functions in excitable tissues such as neurons, cardiac and smooth muscles, whereas the knowledge of BK channels in bone tissues and osteoblasts remains elusive. To investigate the role of BK channels in osteoblasts, we used transcription activator-like effector nuclease (TALEN) to establish a BK knockout cell line on rat ROS17/2.8 osteoblast, and detected the proliferation and mineralization of the BK-knockout cells. Our study found that the BK-knockout cells significantly decreased the ability of proliferation and mineralization as osteoblasts, compared to the wild type cells. The overall expression of osteoblast differentiation marker genes in the BK-knockout cells was significantly lower than that in wild type osteoblast cells. The BK-knockout osteoblast cell line in our study displays a phenotype decrease in osteoblast function which can mimic the pathological state of osteoblast and thus provide a working cell line as a tool for study of osteoblast function and bone related diseases.
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Affiliation(s)
- Hongya Hei
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
| | - Jianjun Gao
- Department of Bone Metabolism, Institute of Radiation Medicine, Fudan University, Shanghai, 200032,
China
| | - Jibin Dong
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
| | - Jie Tao
- Department of Nephrology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062,
China
| | - Lulu Tian
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
| | - Wanma Pan
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
| | - Hongyu Wang
- Department of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016,
China
| | - Xuemei Zhang
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
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32
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Hoshi T, Heinemann SH. Modulation of BK Channels by Small Endogenous Molecules and Pharmaceutical Channel Openers. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 128:193-237. [PMID: 27238265 DOI: 10.1016/bs.irn.2016.03.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Voltage- and Ca(2+)-activated K(+) channels of big conductance (BK channels) are abundantly found in various organs and their relevance for smooth muscle tone and neuronal signaling is well documented. Dysfunction of BK channels is implicated in an array of human diseases involving many organs including the nervous, pulmonary, cardiovascular, renal, and urinary systems. In humans a single gene (KCNMA1) encodes the pore-forming α subunit (Slo1) of BK channels, but the channel properties are variable because of alternative splicing, tissue- and subcellular-specific auxiliary subunits (β, γ), posttranslational modifications, and a multitude of endogenous signaling molecules directly affecting the channel function. Initiatives to develop drugs capable of activating BK channels (channel openers) therefore need to consider the tissue-specific variability of BK channel structure and the potential interference with endogenously produced regulatory factors. The atomic structural basis of BK channel function is only beginning to be revealed. However, building on detailed knowledge of BK channel function, including its single-channel characteristics, voltage- and Ca(2+) dependence of channel gating, and modulation by diffusible messengers, a multi-tier allosteric model of BK channel gating (Horrigan and Aldrich (HA) model) has become a valuable tool in studying modulation of the channel. Using the conceptual framework of the HA model, we here review the functional impact of endogenous modulatory factors and select small synthetic compounds that regulate BK channel activity. Furthermore, we devise experimental approaches for studying BK channel-drug interactions with the aim to classify BK-modulating substances according to their molecular mode of action.
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Affiliation(s)
- T Hoshi
- University of Pennsylvania, Philadelphia, PA, United States.
| | - S H Heinemann
- Friedrich Schiller University Jena & Jena University Hospital, Jena, Germany
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Abstract
BK channels are universal regulators of cell excitability, given their exceptional unitary conductance selective for K(+), joint activation mechanism by membrane depolarization and intracellular [Ca(2+)] elevation, and broad expression pattern. In this chapter, we discuss the structural basis and operational principles of their activation, or gating, by membrane potential and calcium. We also discuss how the two activation mechanisms interact to culminate in channel opening. As members of the voltage-gated potassium channel superfamily, BK channels are discussed in the context of archetypal family members, in terms of similarities that help us understand their function, but also seminal structural and biophysical differences that confer unique functional properties.
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Affiliation(s)
- A Pantazis
- David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, United States
| | - R Olcese
- David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, United States.
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Yu M, Liu SL, Sun PB, Pan H, Tian CL, Zhang LH. Peptide toxins and small-molecule blockers of BK channels. Acta Pharmacol Sin 2016; 37:56-66. [PMID: 26725735 DOI: 10.1038/aps.2015.139] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 10/13/2015] [Indexed: 12/21/2022] Open
Abstract
Large conductance, Ca(2+)-activated potassium (BK) channels play important roles in the regulation of neuronal excitability and the control of smooth muscle contractions. BK channels can be activated by changes in both the membrane potential and intracellular Ca(2+) concentrations. Here, we provide an overview of the structural and pharmacological properties of BK channel blockers. First, the properties of different venom peptide toxins from scorpions and snakes are described, with a focus on their characteristic structural motifs, including their disulfide bond formation pattern, the binding interface between the toxin and BK channel, and the functional consequence of the blockage of BK channels by these toxins. Then, some representative non-peptide blockers of BK channels are also described, including their molecular formula and pharmacological effects on BK channels. The detailed categorization and descriptions of these BK channel blockers will provide mechanistic insights into the blockade of BK channels. The structures of peptide toxins and non-peptide compounds could provide templates for the design of new channel blockers, and facilitate the optimization of lead compounds for further therapeutic applications in neurological disorders or cardiovascular diseases.
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35
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Morera FJ, Saravia J, Pontigo JP, Vargas-Chacoff L, Contreras GF, Pupo A, Lorenzo Y, Castillo K, Tilegenova C, Cuello LG, Gonzalez C. Voltage-dependent BK and Hv1 channels expressed in non-excitable tissues: New therapeutics opportunities as targets in human diseases. Pharmacol Res 2015; 101:56-64. [PMID: 26305431 DOI: 10.1016/j.phrs.2015.08.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/14/2015] [Accepted: 08/14/2015] [Indexed: 11/28/2022]
Abstract
Voltage-gated ion channels are the molecular determinants of cellular excitability. This group of ion channels is one of the most important pharmacological targets in excitable tissues such as nervous system, cardiac and skeletal muscle. Moreover, voltage-gated ion channels are expressed in non-excitable cells, where they mediate key cellular functions through intracellular biochemical mechanisms rather than rapid electrical signaling. This review aims at illustrating the pharmacological impact of these ion channels, highlighting in particular the structural details and physiological functions of two of them - the high conductance voltage- and Ca(2+)-gated K(+) (BK) channels and voltage-gated proton (Hv1) channels- in non-excitable cells. BK channels have been implicated in a variety of physiological processes ranging from regulation of smooth muscle tone to modulation of hormone and neurotransmitter release. Interestingly, BK channels are also involved in modulating K(+) transport in the mammalian kidney and colon epithelium with a potential role in the hyperkalemic phenotype observed in patients with familial hyperkalemic hypertension type 2, and in the pathophysiology of hypertension. In addition, BK channels are responsible for resting and stimulated Ca(2+)-activated K(+) secretion in the distal colon. Hv1 channels have been detected in many cell types, including macrophages, blood cells, lung epithelia, skeletal muscle and microglia. These channels have a central role in the phagocytic system. In macrophages, Hv1 channels participate in the generation of reactive oxygen species in the respiratory burst during the process of phagocytosis.
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Affiliation(s)
- Francisco J Morera
- Institute of Pharmacology and Morphophysiology, Faculty of Veterinary Sciences, Universidad Austral de Chile, Valdivia, Chile.
| | - Julia Saravia
- Institute of Pharmacology and Morphophysiology, Faculty of Veterinary Sciences, Universidad Austral de Chile, Valdivia, Chile
| | - Juan Pablo Pontigo
- Institute of Marine Sciences and Limnology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile
| | - Luis Vargas-Chacoff
- Institute of Marine Sciences and Limnology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile
| | - Gustavo F Contreras
- Interdisciplinary Center for Neuroscience of Valparaiso, Faculty of Sciences, Universidad de Valparaiso, Valparaiso, Chile
| | - Amaury Pupo
- Interdisciplinary Center for Neuroscience of Valparaiso, Faculty of Sciences, Universidad de Valparaiso, Valparaiso, Chile
| | - Yenisleidy Lorenzo
- Interdisciplinary Center for Neuroscience of Valparaiso, Faculty of Sciences, Universidad de Valparaiso, Valparaiso, Chile
| | - Karen Castillo
- Interdisciplinary Center for Neuroscience of Valparaiso, Faculty of Sciences, Universidad de Valparaiso, Valparaiso, Chile
| | - Cholpon Tilegenova
- Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubcock, TX, USA
| | - Luis G Cuello
- Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubcock, TX, USA.
| | - Carlos Gonzalez
- Interdisciplinary Center for Neuroscience of Valparaiso, Faculty of Sciences, Universidad de Valparaiso, Valparaiso, Chile.
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Leo MD, Bulley S, Bannister JP, Kuruvilla KP, Narayanan D, Jaggar JH. Angiotensin II stimulates internalization and degradation of arterial myocyte plasma membrane BK channels to induce vasoconstriction. Am J Physiol Cell Physiol 2015; 309:C392-402. [PMID: 26179602 DOI: 10.1152/ajpcell.00127.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 06/29/2015] [Indexed: 11/22/2022]
Abstract
Arterial smooth muscle cells (myocytes) express large-conductance Ca(2+)-activated K(+) (BK) channel α and auxiliary β1 subunits that modulate arterial contractility. In arterial myocytes, β1 subunits are stored within highly mobile rab11A-positive recycling endosomes. In contrast, BKα subunits are primarily plasma membrane-localized. Trafficking pathways for BKα and whether physiological stimuli that regulate arterial contractility alter BKα localization in arterial myocytes are unclear. Here, using biotinylation, immunofluorescence resonance energy transfer (immunoFRET) microscopy, and RNAi-mediated knockdown, we demonstrate that rab4A-positive early endosomes traffic BKα to the plasma membrane in myocytes of resistance-size cerebral arteries. Angiotensin II (ANG II), a vasoconstrictor, reduced both surface and total BKα, an effect blocked by bisindolylmaleimide-II, concanavalin A, and dynasore, protein kinase C (PKC), internalization, and endocytosis inhibitors, respectively. In contrast, ANG II did not reduce BKα mRNA, and sodium nitroprusside, a nitric oxide donor, did not alter surface BKα protein over the same time course. MG132 and bafilomycin A, proteasomal and lysosomal inhibitors, respectively, also inhibited the ANG II-induced reduction in surface and total BKα, resulting in intracellular BKα accumulation. ANG II-mediated BK channel degradation reduced BK currents in isolated myocytes and functional responses to iberiotoxin, a BK channel blocker, and NS1619, a BK activator, in pressurized (60 mmHg) cerebral arteries. These data indicate that rab4A-positive early endosomes traffic BKα to the plasma membrane in arterial myocytes. We also show that ANG II stimulates PKC-dependent BKα internalization and degradation. These data describe a unique mechanism by which ANG II inhibits arterial myocyte BK currents, by reducing surface channel number, to induce vasoconstriction.
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Affiliation(s)
- M Dennis Leo
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Simon Bulley
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - John P Bannister
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Korah P Kuruvilla
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Damodaran Narayanan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Jonathan H Jaggar
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
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Koulouridis E, Koulouridis I. Molecular pathophysiology of Bartter's and Gitelman's syndromes. World J Pediatr 2015; 11:113-25. [PMID: 25754753 DOI: 10.1007/s12519-015-0016-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 10/23/2014] [Indexed: 12/17/2022]
Abstract
BACKGROUND In the last two decades, progress in cytogenetic and genome research has enabled investigators to unravel the underlying molecular mechanisms of inherited tubulopathies such as Bartter's and Gitelman's syndromes and helped physicians to better understand not only these two pathologic entities but also renal pathophysiology and salt sensitive hypertension. DATA SOURCES Articles collected from PubMed and open access journals included original articles, research articles, and comprehensive reviews. They were evaluated by the authors with an special emphasis on originality and up to date information about molecular pathophysiology. RESULTS Bartter's and Gitelman's syndromes are two different inherited salt loosing tubulopathies. They are characterized by various inability of distal nephron to reabsorb sodium chloride with resultant extarcellular volume contraction and increased activity of the renin angiotensin aldosterone system. Hypokalemic metabolic alkalosis is a common feature of these two forms of tubulopathies. Hypercalciuria characterizes the majority of Bartter's syndrome, and hypomagnesemia with hypocalciuria characterizes Gitelman's syndrome. Low blood pressure is a common feature among patients who suffered from these tubulopathies. Bartter's syndromes encompass a heterogeneous group of ion channels defects localized at the thick ascending limp of Henle's loop with resultant loss of function of sodium-potassium-2 chloride cotransporter. These defects result in the impairment of the countercurrent multiplication system of the kidney as well as calcium, potassium and acid base disturbances which in the majority of cases are proved lethal especially in the antenatal and/or immediate postnatal life period. The underlying pathology in Gitelman's syndrome is defined to the distal convoluted tubule and is related to loss of function of the sodium-chloride cotransporter. The results of this defect encompass the inability of extracellular volume homeostasis, magnesium and potassium conservation, and acid base disturbances which are generally mild and in the majority of cases are not life-threatening. CONCLUSIONS Recent advances in molecular pathophysiology of Bartter's and Gitelman's syndromes have helped physicians to better understand the underlying mechanisms of these pathologic entities which remain obscure. Data collected from experiments among genetically manipulated animals enable us to better understand the pathophysiology of mammalian kidney and the underlying mechanisms of salt sensitive hypertension and to lay a foundation for the future development of new drugs, especially diuretics and antihypertensive drugs.
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Penton D, Czogalla J, Loffing J. Dietary potassium and the renal control of salt balance and blood pressure. Pflugers Arch 2015; 467:513-30. [PMID: 25559844 DOI: 10.1007/s00424-014-1673-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 01/09/2023]
Abstract
Dietary potassium (K(+)) intake has antihypertensive effects, prevents strokes, and improves cardiovascular outcomes. The underlying mechanism for these beneficial effects of high K(+) diets may include vasodilation, enhanced urine flow, reduced renal renin release, and negative sodium (Na(+)) balance. Indeed, several studies demonstrate that dietary K(+) intake induces renal Na(+) loss despite elevated plasma aldosterone. This review briefly highlights the epidemiological and experimental evidences for the effects of dietary K(+) on arterial blood pressure. It discusses the pivotal role of the renal distal tubule for the regulation of urinary K(+) and Na(+) excretion and blood pressure and highlights that it depends on the coordinated interaction of different nephron portions, epithelial cell types, and various ion channels, transporters, and ATPases. Moreover, we discuss the relevance of aldosterone and aldosterone-independent factors in mediating the effects of an altered K(+) intake on renal K(+) and Na(+) handling. Particular focus is given to findings suggesting that an aldosterone-independent downregulation of the thiazide-sensitive NaCl cotransporter significantly contributes to the natriuretic and antihypertensive effect of a K(+)-rich diet. Last but not least, we refer to the complex signaling pathways enabling the kidney to adapt its function to the homeostatic needs in response to an altered K(+) intake. Future work will have to further address the underlying cellular and molecular mechanism and to elucidate, among others, how an altered dietary K(+) intake is sensed and how this signal is transmitted to the different epithelial cells lining the distal tubule.
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Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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Torres YP, Granados ST, Latorre R. Pharmacological consequences of the coexpression of BK channel α and auxiliary β subunits. Front Physiol 2014; 5:383. [PMID: 25346693 PMCID: PMC4193333 DOI: 10.3389/fphys.2014.00383] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 09/16/2014] [Indexed: 01/03/2023] Open
Abstract
Coded by a single gene (Slo1, KCM) and activated by depolarizing potentials and by a rise in intracellular Ca(2+) concentration, the large conductance voltage- and Ca(2+)-activated K(+) channel (BK) is unique among the superfamily of K(+) channels. BK channels are tetramers characterized by a pore-forming α subunit containing seven transmembrane segments (instead of the six found in voltage-dependent K(+) channels) and a large C terminus composed of two regulators of K(+) conductance domains (RCK domains), where the Ca(2+)-binding sites reside. BK channels can be associated with accessory β subunits and, although different BK modulatory mechanisms have been described, greater interest has recently been placed on the role that the β subunits may play in the modulation of BK channel gating due to its physiological importance. Four β subunits have currently been identified (i.e., β1, β2, β3, and β4) and despite the fact that they all share the same topology, it has been shown that every β subunit has a specific tissue distribution and that they modify channel kinetics as well as their pharmacological properties and the apparent Ca(2+) sensitivity of the α subunit in different ways. Additionally, different studies have shown that natural, endogenous, and synthetic compounds can modulate BK channels through β subunits. Considering the importance of these channels in different pathological conditions, such as hypertension and neurological disorders, this review focuses on the mechanisms by which these compounds modulate the biophysical properties of BK channels through the regulation of β subunits, as well as their potential therapeutic uses for diseases such as those mentioned above.
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Affiliation(s)
- Yolima P Torres
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana Bogotá, Colombia
| | - Sara T Granados
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana Bogotá, Colombia ; Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
| | - Ramón Latorre
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso Valparaíso, Chile
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40
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Gao N, Wang H, Zhang X, Yang Z. The inhibitory effect of angiotensin II on BKCa channels in podocytes via oxidative stress. Mol Cell Biochem 2014; 398:217-22. [PMID: 25234195 DOI: 10.1007/s11010-014-2221-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/13/2014] [Indexed: 01/11/2023]
Abstract
Angiotensin II (Ang II) is an important active substance of the renin-angiotensin system (RAS). The present study has confirmed that abnormalities of Ang II may be related with cerebrovascular diseases, endocrine diseases, cardiovascular diseases, liver diseases, such as: cerebral hypoxia, diabetes, obesity, atrial fibrillation, and liver cirrhosis. However, understanding effects of Ang II on podocytes is not enough. This study was to investigate the effects of oxidative stress on the large conductance, Ca(2+)-activated K(+) channels (BKCa). Results from the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay showed that Ang II induced podocyte death in a concentration-dependent manner. The measurement of superoxide dismutase (SOD) generation demonstrated that Ang II decreased the total SOD of cellular levels. Meaningfully, pretreatment of a type of ROS scavenger formulations named N-(mercaptopropionyl)-glycine (N-MPG) could inhibit podocyte apoptosis induced by Ang II. Meanwhile, patch-clamp technique was used in this study to detect the effects of Ang II on currents of BKCa channel in podocytes. The results indicated that Ang II inhibited the current amplitude of BKCa channel and decreased the slope of I-V curve. Ang II also made the activation curves of BKCa channel shift to the left. These results may provide a theoretical basis for potential treatment of chronic glomerular disease in the future.
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Affiliation(s)
- Na Gao
- School of Medicine, State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Nankai University, Tianjin, 300071, China
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Dormanns K, van Disseldorp EMJ, Brown RG, David T. Neurovascular coupling and the influence of luminal agonists via the endothelium. J Theor Biol 2014; 364:49-70. [PMID: 25167790 DOI: 10.1016/j.jtbi.2014.08.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 08/15/2014] [Accepted: 08/18/2014] [Indexed: 11/18/2022]
Abstract
A numerical model of neurovascular coupling (NVC) is presented based on neuronal activity coupled to vasodilation/contraction models via the astrocytic mediated perivascular K(+) and the smooth muscle cell Ca(2+) pathway. Luminal agonists acting on P2Y receptors on the endothelial cell surface provide a flux of IP3 into the endothelial cytosol. This concentration of IP3 is transported via gap junctions between endothelial and smooth muscle cells providing a source of sacroplasmic derived Ca(2+) in the smooth muscle cell. The model is able to relate a neuronal input signal to the corresponding vessel reaction. Results indicate that blood flow mediated IP3 production via the agonist ATP has a substantial effect on the contraction/dilation dynamics of the SMC. The resulting variation in cytosolic Ca(2+) can enhance and inhibit the flow of blood to the cortical tissue. IP3 coupling between endothelial and smooth muscle cells seems to be important in the dynamics of the smooth muscle cell. The VOCC channels are, due to the hyperpolarisation from K(+) SMC efflux, almost entirely closed and do not seem to play a significant role during neuronal activity. The current model shows that astrocytic Ca(2+) is not necessary for neurovascular coupling to occur in contrast to a number of experiments outlining the importance of astrocytic Ca(2+) in NVC, however this Ca(2+) pathway is not the only one mediating NVC. Importantly agonists in flowing blood have a significant influence on the endothelial and smooth muscle cell dynamics.
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Affiliation(s)
- K Dormanns
- Bluefern Supercomputing Unit, University of Canterbury, Christchurch, New Zealand
| | - E M J van Disseldorp
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - R G Brown
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - T David
- Bluefern Supercomputing Unit, University of Canterbury, Christchurch, New Zealand.
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Large conductance Ca2+-activated K+ channel (BKCa) α-subunit splice variants in resistance arteries from rat cerebral and skeletal muscle vasculature. PLoS One 2014; 9:e98863. [PMID: 24921651 PMCID: PMC4055454 DOI: 10.1371/journal.pone.0098863] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 05/07/2014] [Indexed: 11/19/2022] Open
Abstract
Previous studies report functional differences in large conductance Ca2+ activated-K+ channels (BKCa) of smooth muscle cells (VSMC) from rat cerebral and cremaster muscle resistance arteries. The present studies aimed to determine if this complexity in BKCa activity may, in part, be due to splice variants in the pore-forming α-subunit. BKCa variants in the intracellular C terminus of the α-subunit, and their relative expression to total α-subunit, were examined by qPCR. Sequencing of RT-PCR products showed two α-subunit variants, ZERO and STREX, to be identical in cremaster and cerebral arteries. Levels of STREX mRNA expression were, however, significantly higher in cremaster VSMCs (28.9±4.2% of total α-BKCa) compared with cerebral vessels (16.5±0.9%). Further, a low level of BKCa SS4 α-subunit variant was seen in cerebral arteries, while undetectable in cremaster arteries. Protein biotinylation assays, in expression systems and arterial preparations, were used to determine whether differences in splice variant mRNA expression affect surface membrane/cytosolic location of the channel. In AD-293 and CHO-K1 cells, rat STREX was more likely to be located at the plasma membrane compared to ZERO, although the great majority of channel protein was in the membrane in both cases. Co-expression of β1-BKCa subunit with STREX or ZERO did not influence the dominant membrane expression of α-BKCa subunits, whereas in the absence of α-BKCa, a significant proportion of β1-subunit remained cytosolic. Biotinylation assays of cremaster and cerebral arteries showed that differences in STREX/ZERO expression do not alter membrane/cytosolic distribution of the channel under basal conditions. These data, however, revealed that the amount of α-BKCa in cerebral arteries is approximately 20X higher than in cremaster vessels. Thus, the data support the major functional differences in BKCa activity in cremaster, as compared to cerebral VSMCs, being related to total α-BKCa expression, regardless of differences in splice variant expression.
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43
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Evanson KW, Bannister JP, Leo MD, Jaggar JH. LRRC26 is a functional BK channel auxiliary γ subunit in arterial smooth muscle cells. Circ Res 2014; 115:423-31. [PMID: 24906643 DOI: 10.1161/circresaha.115.303407] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RATIONALE Smooth muscle cell (myocyte) large-conductance calcium (Ca)(2+)-activated potassium (BK) channels are functionally significant modulators of arterial contractility. Arterial myocytes express both pore-forming BKα and auxiliary β1 subunits, which increase channel Ca(2+) sensitivity. Recently, several leucine-rich repeat containing (LRRC) proteins have been identified as auxiliary γ subunits that elevate the voltage sensitivity of recombinant and prostate adenocarcinoma BK channels. LRRC expression and physiological functions in native cell types are unclear. OBJECTIVE Investigate the expression and physiological functions of leucine-rich repeat containing protein 26 (LRRC26) in arterial myocytes. METHODS AND RESULTS Reverse transcription polymerase chain reaction and Western blotting detected LRRC26 mRNA and protein in cerebral artery myocytes. Biotinylation, immunofluorescence resonance energy transfer microscopy, and coimmunoprecipitation indicated that LRRC26 was located in close spatial proximity to, and associated with, plasma membrane BKα subunits. LRRC26 knockdown (RNAi) reduced total and surface LRRC26, but did not alter BKα or β1, proteins in arteries. LRRC26 knockdown did not alter Ca(2+) sparks but reduced BK channel voltage sensitivity, which decreased channel apparent Ca(2+) sensitivity and transient BK current frequency and amplitude in myocytes. LRRC26 knockdown also increased myogenic tone over a range (40-100 mm Hg) of intravascular pressures, and reduced vasoconstriction to iberiotoxin and vasodilation to NS1619, BK channel inhibitors and activators, respectively. In contrast, LRRC26 knockdown did not alter depolarization (60 mmol/L K(+))-induced vasoconstriction. CONCLUSIONS LRRC26 is expressed, associates with BKα subunits, and elevates channel voltage- and apparent Ca(2+) sensitivity in arterial myocytes to induce vasodilation. This study indicates that arterial myocytes express a functional BK channel γ subunit.
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Affiliation(s)
- Kirk W Evanson
- From the Department of Physiology, University of Tennessee Health Science Center, Memphis
| | - John P Bannister
- From the Department of Physiology, University of Tennessee Health Science Center, Memphis
| | - M Dennis Leo
- From the Department of Physiology, University of Tennessee Health Science Center, Memphis
| | - Jonathan H Jaggar
- From the Department of Physiology, University of Tennessee Health Science Center, Memphis.
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Shelton EL, Ector G, Galindo CL, Hooper CW, Brown N, Wilkerson I, Pfaltzgraff ER, Paria BC, Cotton RB, Stoller JZ, Reese J. Transcriptional profiling reveals ductus arteriosus-specific genes that regulate vascular tone. Physiol Genomics 2014; 46:457-66. [PMID: 24790087 DOI: 10.1152/physiolgenomics.00171.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Failure of the ductus arteriosus (DA) to close at birth can lead to serious complications. Conversely, certain profound congenital cardiac malformations require the DA to be patent until corrective surgery can be performed. In each instance, clinicians have a very limited repertoire of therapeutic options at their disposal - indomethacin or ibuprofen to close a patent DA (PDA) and prostaglandin E1 to maintain patency of the DA. Neither treatment is specific to the DA and both may have deleterious off-target effects. Therefore, more therapeutic options specifically targeted to the DA should be considered. We hypothesized the DA possesses a unique genetic signature that would set it apart from other vessels. A microarray was used to compare the genetic profiles of the murine DA and ascending aorta (AO). Over 4,000 genes were differentially expressed between these vessels including a subset of ion channel-related genes. Specifically, the alpha and beta subunits of large-conductance calcium-activated potassium (BKCa) channels are enriched in the DA. Gain- and loss-of-function studies showed inhibition of BKCa channels caused the DA to constrict, while activation caused DA relaxation even in the presence of O2. This study identifies subsets of genes that are enriched in the DA that may be used to develop DA-specific drugs. Ion channels that regulate DA tone, including BKCa channels, are promising targets. Specifically, BKCa channel agonists like NS1619 maintain DA patency even in the presence of O2 and may be clinically useful.
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Affiliation(s)
- Elaine L Shelton
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee;
| | - Gerren Ector
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Cristi L Galindo
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - Christopher W Hooper
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Naoko Brown
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Irene Wilkerson
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Elise R Pfaltzgraff
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Bibhash C Paria
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Robert B Cotton
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Jason Z Stoller
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Jeff Reese
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
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Sachse G, Faulhaber J, Seniuk A, Ehmke H, Pongs O. Smooth muscle BK channel activity influences blood pressure independent of vascular tone in mice. J Physiol 2014; 592:2563-74. [PMID: 24687584 DOI: 10.1113/jphysiol.2014.272880] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The large conductance voltage- and Ca(2+)-activated K(+) (BK) channel is an important determinant of vascular tone and contributes to blood pressure regulation. Both activities depend on the ancillary BKβ1 subunit. To determine the significance of smooth muscle BK channel activity for blood pressure regulation, we investigated the potential link between changes in arterial tone and altered blood pressure in BKβ1 knockout (BKβ1(-/-)) mice from three different genetically defined strains. While vascular tone was consistently increased in all BKβ1(-/-) mice independent of genetic background, BKβ1(-/-) strains exhibited increased (strain A), unaltered (strain B) or decreased (strain C) mean arterial blood pressures compared to their corresponding BKβ1(+/+) controls. In agreement with previous data on aldosterone regulation by renal/adrenal BK channel function, BKβ1(-/-) strain A mice have increased plasma aldosterone and increased blood pressure. Consistently, blockade of mineralocorticoid receptors by spironolactone treatment reversibly restored the elevated blood pressure to the BKβ1(+/+) strain A level. In contrast, loss of BKβ1 did not affect plasma aldosterone in strain C mice. Smooth muscle-restricted restoration of BKβ1 expression increased blood pressure in BKβ1(-/-) strain C mice, implying that impaired smooth muscle BK channel activity lowers blood pressure in these animals. We conclude that BK channel activity directly affects vascular tone but influences blood pressure independent of this effect via different pathways.
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Affiliation(s)
- Gregor Sachse
- Institut für Neurale Signalverarbeitung, Zentrum für Molekulare Neurobiologie, Falkenried 94, D-20251, Hamburg, Germany Department of Physiology, Anatomy and Genetics, South Parks Road, Oxford, OX1 3QX, UK
| | - Jörg Faulhaber
- Institut für Zelluläre und Integrative Physiologie, UKE, Martinistr. 52, D-20246, Hamburg, Germany
| | - Anika Seniuk
- Institut für Zelluläre und Integrative Physiologie, UKE, Martinistr. 52, D-20246, Hamburg, Germany
| | - Heimo Ehmke
- Institut für Zelluläre und Integrative Physiologie, UKE, Martinistr. 52, D-20246, Hamburg, Germany
| | - Olaf Pongs
- Institut für Neurale Signalverarbeitung, Zentrum für Molekulare Neurobiologie, Falkenried 94, D-20251, Hamburg, Germany Institut für Physiologie (Geb 56), Universität des Saarlandes, 66421, Homburg/Saar, Germany
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Dynamic regulation of β1 subunit trafficking controls vascular contractility. Proc Natl Acad Sci U S A 2014; 111:2361-6. [PMID: 24464482 DOI: 10.1073/pnas.1317527111] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Ion channels composed of pore-forming and auxiliary subunits control physiological functions in virtually all cell types. A conventional view is that channels assemble with their auxiliary subunits before anterograde plasma membrane trafficking of the protein complex. Whether the multisubunit composition of surface channels is fixed following protein synthesis or flexible and open to acute and, potentially, rapid modulation to control activity and cellular excitability is unclear. Arterial smooth muscle cells (myocytes) express large-conductance Ca(2+)-activated potassium (BK) channel α and auxiliary β1 subunits that are functionally significant modulators of arterial contractility. Here, we show that native BKα subunits are primarily (∼95%) plasma membrane-localized in human and rat arterial myocytes. In contrast, only a small fraction (∼10%) of total β1 subunits are located at the cell surface. Immunofluorescence resonance energy transfer microscopy demonstrated that intracellular β1 subunits are stored within Rab11A-postive recycling endosomes. Nitric oxide (NO), acting via cGMP-dependent protein kinase, and cAMP-dependent pathways stimulated rapid (≤1 min) anterograde trafficking of β1 subunit-containing recycling endosomes, which increased surface β1 almost threefold. These β1 subunits associated with surface-resident BKα proteins, elevating channel Ca(2+) sensitivity and activity. Our data also show that rapid β1 subunit anterograde trafficking is the primary mechanism by which NO activates myocyte BK channels and induces vasodilation. In summary, we show that rapid β1 subunit surface trafficking controls functional BK channel activity in arterial myocytes and vascular contractility. Conceivably, regulated auxiliary subunit trafficking may control ion channel activity in a wide variety of cell types.
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González C, Baez-Nieto D, Valencia I, Oyarzún I, Rojas P, Naranjo D, Latorre R. K(+) channels: function-structural overview. Compr Physiol 2013; 2:2087-149. [PMID: 23723034 DOI: 10.1002/cphy.c110047] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Potassium channels are particularly important in determining the shape and duration of the action potential, controlling the membrane potential, modulating hormone secretion, epithelial function and, in the case of those K(+) channels activated by Ca(2+), damping excitatory signals. The multiplicity of roles played by K(+) channels is only possible to their mammoth diversity that includes at present 70 K(+) channels encoding genes in mammals. Today, thanks to the use of cloning, mutagenesis, and the more recent structural studies using x-ray crystallography, we are in a unique position to understand the origins of the enormous diversity of this superfamily of ion channels, the roles they play in different cell types, and the relations that exist between structure and function. With the exception of two-pore K(+) channels that are dimers, voltage-dependent K(+) channels are tetrameric assemblies and share an extremely well conserved pore region, in which the ion-selectivity filter resides. In the present overview, we discuss in the function, localization, and the relations between function and structure of the five different subfamilies of K(+) channels: (a) inward rectifiers, Kir; (b) four transmembrane segments-2 pores, K2P; (c) voltage-gated, Kv; (d) the Slo family; and (e) Ca(2+)-activated SK family, SKCa.
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Affiliation(s)
- Carlos González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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Hoshi T, Pantazis A, Olcese R. Transduction of voltage and Ca2+ signals by Slo1 BK channels. Physiology (Bethesda) 2013; 28:172-89. [PMID: 23636263 DOI: 10.1152/physiol.00055.2012] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Large-conductance Ca2+ -and voltage-gated K+ channels are activated by an increase in intracellular Ca2+ concentration and/or depolarization. The channel activation mechanism is well described by an allosteric model encompassing the gate, voltage sensors, and Ca2+ sensors, and the model is an excellent framework to understand the influences of auxiliary β and γ subunits and regulatory factors such as Mg2+. Recent advances permit elucidation of structural correlates of the biophysical mechanism.
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Affiliation(s)
- T Hoshi
- Department of Physiology, The University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Latorre R, Contreras G. Keeping you healthy: BK channel activation by omega-3 fatty acids. ACTA ACUST UNITED AC 2013; 142:487-91. [PMID: 24127527 PMCID: PMC3813380 DOI: 10.1085/jgp.201311100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2366103, Chile
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Angsanakul J, Sitprija V. Scorpion venoms, kidney and potassium. Toxicon 2013; 73:81-7. [DOI: 10.1016/j.toxicon.2013.06.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 05/23/2013] [Accepted: 06/27/2013] [Indexed: 01/28/2023]
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