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Wolpe AG, Luse MA, Baryiames C, Schug WJ, Wolpe JB, Johnstone SR, Dunaway LS, Juśkiewicz ZJ, Loeb SA, Askew Page HR, Chen YL, Sabapathy V, Pavelec CM, Wakefield B, Cifuentes-Pagano E, Artamonov MV, Somlyo AV, Straub AC, Sharma R, Beier F, Barrett EJ, Leitinger N, Pagano PJ, Sonkusare SK, Redemann S, Columbus L, Penuela S, Isakson BE. Pannexin-3 stabilizes the transcription factor Bcl6 in a channel-independent manner to protect against vascular oxidative stress. Sci Signal 2024; 17:eadg2622. [PMID: 38289985 DOI: 10.1126/scisignal.adg2622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 01/05/2024] [Indexed: 02/01/2024]
Abstract
Targeted degradation regulates the activity of the transcriptional repressor Bcl6 and its ability to suppress oxidative stress and inflammation. Here, we report that abundance of endothelial Bcl6 is determined by its interaction with Golgi-localized pannexin 3 (Panx3) and that Bcl6 transcriptional activity protects against vascular oxidative stress. Consistent with data from obese, hypertensive humans, mice with an endothelial cell-specific deficiency in Panx3 had spontaneous systemic hypertension without obvious changes in channel function, as assessed by Ca2+ handling, ATP amounts, or Golgi luminal pH. Panx3 bound to Bcl6, and its absence reduced Bcl6 protein abundance, suggesting that the interaction with Panx3 stabilized Bcl6 by preventing its degradation. Panx3 deficiency was associated with increased expression of the gene encoding the H2O2-producing enzyme Nox4, which is normally repressed by Bcl6, resulting in H2O2-induced oxidative damage in the vasculature. Catalase rescued impaired vasodilation in mice lacking endothelial Panx3. Administration of a newly developed peptide to inhibit the Panx3-Bcl6 interaction recapitulated the increase in Nox4 expression and in blood pressure seen in mice with endothelial Panx3 deficiency. Panx3-Bcl6-Nox4 dysregulation occurred in obesity-related hypertension, but not when hypertension was induced in the absence of obesity. Our findings provide insight into a channel-independent role of Panx3 wherein its interaction with Bcl6 determines vascular oxidative state, particularly under the adverse conditions of obesity.
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Affiliation(s)
- Abigail G Wolpe
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Melissa A Luse
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | | | - Wyatt J Schug
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Jacob B Wolpe
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Scott R Johnstone
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Center for Vascular and Heart Research, Roanoke, VA 24016, USA
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24060, USA
| | - Luke S Dunaway
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Zuzanna J Juśkiewicz
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Skylar A Loeb
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Henry R Askew Page
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Yen-Lin Chen
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Vikram Sabapathy
- Center for Immunity, Inflammation, and Regenerative Medicine (CIIR), University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Caitlin M Pavelec
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Brent Wakefield
- Department of Anatomy and Cell Biology, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Eugenia Cifuentes-Pagano
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Mykhaylo V Artamonov
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Avril V Somlyo
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Adam C Straub
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Rahul Sharma
- Center for Immunity, Inflammation, and Regenerative Medicine (CIIR), University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Frank Beier
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Eugene J Barrett
- Department of Medicine, Division of Endocrinology and Metabolism, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Norbert Leitinger
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Patrick J Pagano
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Swapnil K Sonkusare
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Stefanie Redemann
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
- Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA
| | - Silvia Penuela
- Department of Anatomy and Cell Biology, University of Western Ontario, London, ON N6A 5C1, Canada
- Department of Oncology (Division of Experimental Oncology), Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5W9, Canada
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
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Behringer EJ. Impact of aging on vascular ion channels: perspectives and knowledge gaps across major organ systems. Am J Physiol Heart Circ Physiol 2023; 325:H1012-H1038. [PMID: 37624095 PMCID: PMC10908410 DOI: 10.1152/ajpheart.00288.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/21/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023]
Abstract
Individuals aged ≥65 yr will comprise ∼20% of the global population by 2030. Cardiovascular disease remains the leading cause of death in the world with age-related endothelial "dysfunction" as a key risk factor. As an organ in and of itself, vascular endothelium courses throughout the mammalian body to coordinate blood flow to all other organs and tissues (e.g., brain, heart, lung, skeletal muscle, gut, kidney, skin) in accord with metabolic demand. In turn, emerging evidence demonstrates that vascular aging and its comorbidities (e.g., neurodegeneration, diabetes, hypertension, kidney disease, heart failure, and cancer) are "channelopathies" in large part. With an emphasis on distinct functional traits and common arrangements across major organs systems, the present literature review encompasses regulation of vascular ion channels that underlie blood flow control throughout the body. The regulation of myoendothelial coupling and local versus conducted signaling are discussed with new perspectives for aging and the development of chronic diseases. Although equipped with an awareness of knowledge gaps in the vascular aging field, a section has been included to encompass general feasibility, role of biological sex, and additional conceptual and experimental considerations (e.g., cell regression and proliferation, gene profile analyses). The ultimate goal is for the reader to see and understand major points of deterioration in vascular function while gaining the ability to think of potential mechanistic and therapeutic strategies to sustain organ perfusion and whole body health with aging.
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Affiliation(s)
- Erik J Behringer
- Basic Sciences, Loma Linda University, Loma Linda, California, United States
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Hakim MA, Behringer EJ. K IR channel regulation of electrical conduction along cerebrovascular endothelium: Enhanced modulation during Alzheimer's disease. Microcirculation 2023; 30:e12797. [PMID: 36577656 PMCID: PMC9885900 DOI: 10.1111/micc.12797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 11/22/2022] [Accepted: 12/22/2022] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Endothelial cell (EC) coupling occurs through gap junctions and underlies cerebral blood flow regulation governed by inward-rectifying K+ (KIR ) channels. This study addressed effects of KIR channel activity on EC coupling before and during Alzheimer's disease (AD). METHODS Intact EC tubes (width: ~90-100 μm; length: ~0.5 mm) were freshly isolated from posterior cerebral arteries of young Pre-AD (1-3 months) and aged AD (13-18 months) male and female 3xTg-AD mice. Dual intracellular microelectrodes applied simultaneous current injections (±0.5-3 nA) and membrane potential (Vm ) recordings in ECs at distance ~400 μm. Elevated extracellular potassium ([K+ ]E ; 8-15 mmol/L; reference, 5 mmol/L) activated KIR channels. RESULTS Conducted Vm (∆Vm ) responses ranged from ~-30 to 30 mV in response to -3 to +3 nA (linear regression, R2 ≥ .99) while lacking rectification for charge polarity or axial direction of spread. Conduction slope decreased ~10%-20% during 15 mmol/L [K+ ]E in Pre-AD males and AD females. 15 mmol/L [K+ ]E decreased conduction by ~10%-20% at lower ∆Vm thresholds in AD animals (~±20 mV) versus Pre-AD (~±25 mV). AD increased conducted hyperpolarization by ~10%-15% during 8-12 mmol/L [K+ ]E . CONCLUSIONS Brain endothelial KIR channel activity modulates bidirectional spread of vasoreactive signals with enhanced regulation of EC coupling during AD pathology.
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Affiliation(s)
- Md A. Hakim
- Basic Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - Erik J. Behringer
- Basic Sciences, Loma Linda University, Loma Linda, CA 92350, USA,Corresponding Author: Erik J. Behringer, Ph.D., Department of Basic Sciences, 11041 Campus Street, Risley Hall, Loma Linda University, Loma Linda, CA 92350, , tel: (909) 651-5334, fax: (909) 558-0119
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Murrant CL, Fletcher NM. Capillary communication: the role of capillaries in sensing the tissue environment, coordinating the microvascular, and controlling blood flow. Am J Physiol Heart Circ Physiol 2022; 323:H1019-H1036. [PMID: 36149771 DOI: 10.1152/ajpheart.00088.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Historically, capillaries have been viewed as the microvascular site for flux of nutrients to cells and removal of waste products. Capillaries are the most numerous blood vessel segment within the tissue, whose vascular wall consists of only a single layer of endothelial cells and are situated within microns of each cell of the tissue, all of which optimizes capillaries for the exchange of nutrients between the blood compartment and the interstitial space of tissues. There is, however, a growing body of evidence to support that capillaries play an important role in sensing the tissue environment, coordinating microvascular network responses, and controlling blood flow. Much of our growing understanding of capillaries stems from work in skeletal muscle and more recent work in the brain, where capillaries can be stimulated by products released from cells of the tissue during increased activity and are able to communicate with upstream and downstream vascular segments, enabling capillaries to sense the activity levels of the tissue and send signals to the microvascular network to coordinate the blood flow response. This review will focus on the emerging role that capillaries play in communication between cells of the tissue and the vascular network required to direct blood flow to active cells in skeletal muscle and the brain. We will also highlight the emerging central role that disruptions in capillary communication may play in blood flow dysregulation, pathophysiology, and disease.
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Affiliation(s)
- Coral L Murrant
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Nicole M Fletcher
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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5
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Alloatti G, Penna C, Comità S, Tullio F, Aragno M, Biasi F, Pagliaro P. Aging, sex and NLRP3 inflammasome in cardiac ischaemic disease. Vascul Pharmacol 2022; 145:107001. [PMID: 35623548 DOI: 10.1016/j.vph.2022.107001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/01/2022] [Accepted: 05/20/2022] [Indexed: 10/18/2022]
Abstract
Experimentally, many strong cardioprotective treatments have been identified in different animal models of acute ischaemia/reperfusion injury (IRI) and coronary artery disease (CAD). However, the translation of these cardioprotective therapies for the benefit of the patients into the clinical scenario has been very disappointing. The reasons for this lack are certainly multiple. Indeed, many confounding factors we must deal in clinical reality, such as aging, sex and inflammatory processes are neglected in many experiments. Due to the pivotal role of aging, sex and inflammation in determining cardiac ischaemic disease, in this review, we take into account age as a modifier of tolerance to IRI in the two sexes, dissecting aging and myocardial reperfusion injury mechanisms and the sex differences in tolerance to IRI. Then we focus on the role of the gut microbiota and the NLRP3 inflammasome in myocardial IRI and on the possibility to consider NLRP3 inflammasome as a potential target in the treatment of CAD in relationship with age and sex. Finally, we consider the cardioprotective mechanisms and cardioprotective treatments during aging in the two sexes.
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Affiliation(s)
| | - Claudia Penna
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, Orbassano, 10043 Torino, TO, Italy; National Institute for Cardiovascular Research (INRC), Bologna, Italy
| | - Stefano Comità
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, Orbassano, 10043 Torino, TO, Italy
| | - Francesca Tullio
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, Orbassano, 10043 Torino, TO, Italy
| | - Manuela Aragno
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, Orbassano, 10043 Torino, TO, Italy
| | - Fiorella Biasi
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, Orbassano, 10043 Torino, TO, Italy
| | - Pasquale Pagliaro
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, Orbassano, 10043 Torino, TO, Italy; National Institute for Cardiovascular Research (INRC), Bologna, Italy.
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6
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Sabe SA, Feng J, Sellke FW, Abid MR. Mechanisms and clinical implications of endothelium-dependent vasomotor dysfunction in coronary microvasculature. Am J Physiol Heart Circ Physiol 2022; 322:H819-H841. [PMID: 35333122 PMCID: PMC9018047 DOI: 10.1152/ajpheart.00603.2021] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 03/21/2022] [Accepted: 03/21/2022] [Indexed: 12/16/2022]
Abstract
Coronary microvascular disease (CMD), which affects the arterioles and capillary endothelium that regulate myocardial perfusion, is an increasingly recognized source of morbidity and mortality, particularly in the setting of metabolic syndrome. The coronary endothelium plays a pivotal role in maintaining homeostasis, though factors such as diabetes, hypertension, hyperlipidemia, and obesity can contribute to endothelial injury and consequently arteriolar vasomotor dysfunction. These disturbances in the coronary microvasculature clinically manifest as diminished coronary flow reserve, which is a known independent risk factor for cardiac death, even in the absence of macrovascular atherosclerotic disease. Therefore, a growing body of literature has examined the molecular mechanisms by which coronary microvascular injury occurs at the level of the endothelium and the consequences on arteriolar vasomotor responses. This review will begin with an overview of normal coronary microvascular physiology, modalities of measuring coronary microvascular function, and clinical implications of CMD. These introductory topics will be followed by a discussion of recent advances in the understanding of the mechanisms by which inflammation, oxidative stress, insulin resistance, hyperlipidemia, hypertension, shear stress, endothelial cell senescence, and tissue ischemia dysregulate coronary endothelial homeostasis and arteriolar vasomotor function.
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Affiliation(s)
- Sharif A Sabe
- Cardiovascular Research Center, Rhode Island Hospital, Providence, Rhode Island
- Division of Cardiothoracic Surgery, Alpert Medical School of Brown University and Rhode Island Hospital, Providence, Rhode Island
| | - Jun Feng
- Cardiovascular Research Center, Rhode Island Hospital, Providence, Rhode Island
- Division of Cardiothoracic Surgery, Alpert Medical School of Brown University and Rhode Island Hospital, Providence, Rhode Island
| | - Frank W Sellke
- Cardiovascular Research Center, Rhode Island Hospital, Providence, Rhode Island
- Division of Cardiothoracic Surgery, Alpert Medical School of Brown University and Rhode Island Hospital, Providence, Rhode Island
| | - M Ruhul Abid
- Cardiovascular Research Center, Rhode Island Hospital, Providence, Rhode Island
- Division of Cardiothoracic Surgery, Alpert Medical School of Brown University and Rhode Island Hospital, Providence, Rhode Island
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Gorshkova OP, Sokolova IB. Changes in the Сontribution of IKCa Сhannels to Tone Maintenanсe and Dilation of Pial Arteries in Aging Rats after Ischemia-Reperfusion. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022030152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Hakim MA, Pires PW, Behringer EJ. Isolation and Functional Analysis of Arteriolar Endothelium of Mouse Brain Parenchyma. JOURNAL OF VISUALIZED EXPERIMENTS : JOVE 2022:10.3791/63463. [PMID: 35343953 PMCID: PMC9154351 DOI: 10.3791/63463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cerebral blood flow is conveyed by vascular resistance arteries and downstream parenchymal arterioles. Steady-state vascular resistance to blood flow increases with decreasing diameter from arteries to arterioles that ultimately feed into capillaries. Due to their smaller size and location in the parenchyma, arterioles have been relatively understudied and with less reproducibility in findings than surface pial arteries. Regardless, arteriolar endothelial cell structure and function-integral to the physiology and etiology of chronic degenerative diseases-requires extensive investigation. In particular, emerging evidence demonstrates that compromised endothelial function precedes and exacerbates cognitive impairment and dementia. In the parenchymal microcirculation, endothelial K+ channel function is the most robust stimulus to finely control the spread of vasodilation to promote increases in blood flow to areas of neuronal activity. This paper illustrates a refined method for freshly isolating intact and electrically coupled endothelial "tubes" (diameter, ~25 µm) from mouse brain parenchymal arterioles. Arteriolar endothelial tubes are secured during physiological conditions (37 °C, pH 7.4) to resolve experimental variables that encompass K+ channel function and their regulation, including intracellular Ca2+ dynamics, changes in membrane potential, and membrane lipid regulation. A distinct technical advantage versus arterial endothelium is the enhanced morphological resolution of cell and organelle (e.g., mitochondria) dimensions, which expands the usefulness of this technique. Healthy cerebral perfusion throughout life entails robust endothelial function in parenchymal arterioles, directly linking blood flow to the fueling of neuronal and glial activity throughout precise anatomical regions of the brain. Thus, it is expected that this method will significantly advance the general knowledge of vascular physiology and neuroscience concerning the healthy and diseased brain.
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Affiliation(s)
- Md A. Hakim
- Department of Basic Sciences, Loma Linda University
| | - Paulo W. Pires
- Departments of Physiology, Surgery and Neurosurgery and Sarver Heart Center, University of Arizona College of Medicine Tucson
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Shuvaeva VN, Gorshkova OP. Age-Related Changes in the Contribution of Nitric Oxide and Potassium Channels to Dilation of Rat Pial Arteries. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021060193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Harraz OF, Jensen LJ. Vascular calcium signalling and ageing. J Physiol 2021; 599:5361-5377. [PMID: 34705288 PMCID: PMC9002240 DOI: 10.1113/jp280950] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 10/12/2021] [Indexed: 02/05/2023] Open
Abstract
Changes in cellular Ca2+ levels have major influences on vascular function and blood pressure regulation. Vascular smooth muscle cells (SMCs) and endothelial cells (ECs) orchestrate vascular activity in distinct ways, often involving highly specific fluctuations in Ca2+ signalling. Ageing is a major risk factor for cardiovascular diseases, but the impact of ageing per se on vascular Ca2+ signalling has received insufficient attention. We reviewed the literature for age-related changes in Ca2+ signalling in relation to vascular structure and function. Vascular tone dysregulation in several vascular beds has been linked to abnormal expression or activity of SMC voltage-gated Ca2+ channels, Ca2+ -activated K+ channels or TRPC6 channels. Some of these effects were linked to altered caveolae density, microRNA expression or 20-HETE abundance. Intracellular store Ca2+ handling was suppressed in ageing mainly via reduced expression of intracellular Ca2+ release channels, and Ca2+ reuptake or efflux pumps. An increase in mitochondrial Ca2+ uptake, leading to oxidative stress, could also play a role in SMC hypercontractility and structural remodelling in ageing. In ECs, ageing entailed diverse effects on spontaneous and evoked Ca2+ transients, as well as structural changes at the EC-SMC interface. The concerted effects of altered Ca2+ signalling on myogenic tone, endothelium-dependent vasodilatation, and vascular structure are likely to contribute to blood pressure dysregulation and blood flow distribution deficits in critical organs. With the increase in the world's ageing population, future studies should be directed at solving specific ageing-induced Ca2+ signalling deficits to combat the imminent accelerated vascular ageing and increased risk of cardiovascular diseases.
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Affiliation(s)
- Osama F. Harraz
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA,Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, Vermont, USA
| | - Lars Jørn Jensen
- Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
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11
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Norton CE, Boerman EM, Segal SS. Differential hyperpolarization to substance P and calcitonin gene-related peptide in smooth muscle versus endothelium of mouse mesenteric artery. Microcirculation 2021; 28:e12733. [PMID: 34633728 PMCID: PMC9996665 DOI: 10.1111/micc.12733] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/16/2021] [Accepted: 10/06/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE We sought to define how sensory neurotransmitters substance P and calcitonin gene-related peptide (CGRP) affect membrane potential of vascular smooth muscle and endothelium. METHODS Microelectrodes recorded membrane potential of smooth muscle from pressurized mouse mesenteric arteries (diameter, ~150 µm) and in endothelial tubes. RESULTS Resting potential was similar (~ -45 mV) for each cell layer. Substance P hyperpolarized smooth muscle and endothelium ~ -15 mV; smooth muscle hyperpolarization was abolished by endothelial disruption or NO synthase inhibition. Blocking KCa channels (apamin + charybdotoxin) attenuated hyperpolarization in both cell types. CGRP hyperpolarized endothelium and smooth muscle ~ -30 mV; smooth muscle hyperpolarization was independent of endothelium. Blocking KCa channels prevented hyperpolarization to CGRP in endothelium but not smooth muscle. Inhibiting KATP channels with glibenclamide or genetic deletion of KIR 6.1 attenuated hyperpolarization in smooth muscle but not endothelium. Pinacidil (KATP channel agonist) hyperpolarized smooth muscle more than endothelium (~ -35 vs. ~ -20 mV). CONCLUSIONS Calcitonin gene-related peptide elicits greater hyperpolarization than substance P. Substance P hyperpolarizes both cell layers through KCa channels and involves endothelium-derived NO in smooth muscle. Endothelial hyperpolarization to CGRP requires KCa channels, while KATP channels mediate hyperpolarization in smooth muscle. Differential K+ channel activation in smooth muscle and endothelium through sensory neurotransmission may selectively tune mesenteric blood flow.
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Affiliation(s)
- Charles E Norton
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA.,Dalton Cardiovascular Research Center, Columbia, Missouri, USA
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12
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Tracy EP, Hughes W, Beare JE, Rowe G, Beyer A, LeBlanc AJ. Aging-Induced Impairment of Vascular Function: Mitochondrial Redox Contributions and Physiological/Clinical Implications. Antioxid Redox Signal 2021; 35:974-1015. [PMID: 34314229 PMCID: PMC8905248 DOI: 10.1089/ars.2021.0031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Significance: The vasculature responds to the respiratory needs of tissue by modulating luminal diameter through smooth muscle constriction or relaxation. Coronary perfusion, diastolic function, and coronary flow reserve are drastically reduced with aging. This loss of blood flow contributes to and exacerbates pathological processes such as angina pectoris, atherosclerosis, and coronary artery and microvascular disease. Recent Advances: Increased attention has recently been given to defining mechanisms behind aging-mediated loss of vascular function and development of therapeutic strategies to restore youthful vascular responsiveness. The ultimate goal aims at providing new avenues for symptom management, reversal of tissue damage, and preventing or delaying of aging-induced vascular damage and dysfunction in the first place. Critical Issues: Our major objective is to describe how aging-associated mitochondrial dysfunction contributes to endothelial and smooth muscle dysfunction via dysregulated reactive oxygen species production, the clinical impact of this phenomenon, and to discuss emerging therapeutic strategies. Pathological changes in regulation of mitochondrial oxidative and nitrosative balance (Section 1) and mitochondrial dynamics of fission/fusion (Section 2) have widespread effects on the mechanisms underlying the ability of the vasculature to relax, leading to hyperconstriction with aging. We will focus on flow-mediated dilation, endothelial hyperpolarizing factors (Sections 3 and 4), and adrenergic receptors (Section 5), as outlined in Figure 1. The clinical implications of these changes on major adverse cardiac events and mortality are described (Section 6). Future Directions: We discuss antioxidative therapeutic strategies currently in development to restore mitochondrial redox homeostasis and subsequently vascular function and evaluate their potential clinical impact (Section 7). Antioxid. Redox Signal. 35, 974-1015.
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Affiliation(s)
- Evan Paul Tracy
- Department of Physiology, University of Louisville, Louisville, Kentucky, USA
| | - William Hughes
- Department of Medicine and Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Jason E Beare
- Cardiovascular Innovation Institute, University of Louisville, Louisville, Kentucky, USA.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
| | - Gabrielle Rowe
- Department of Physiology, University of Louisville, Louisville, Kentucky, USA
| | - Andreas Beyer
- Department of Medicine and Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Amanda Jo LeBlanc
- Department of Physiology, University of Louisville, Louisville, Kentucky, USA.,Cardiovascular Innovation Institute, University of Louisville, Louisville, Kentucky, USA
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Mitchell R, Frederick NE, Holzman ER, Agobe F, Allaway HCM, Bagher P. Ifetroban reduces coronary artery dysfunction in a mouse model of Duchenne muscular dystrophy. Am J Physiol Heart Circ Physiol 2021; 321:H52-H58. [PMID: 34048282 DOI: 10.1152/ajpheart.00180.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dilated cardiomyopathy contributes to morbidity and mortality in Duchenne muscular dystrophy (DMD), an inheritable muscle-wasting disease caused by a mutation in the dystrophin gene. Preclinical studies in mouse models of muscular dystrophy have demonstrated reduced cardiomyopathy and improved cardiac function following oral treatment with the potent and selective thromboxane A2/prostanoid receptor (TPr) antagonist ifetroban. Furthermore, a phase 2 clinical trial (NCT03340675, Cumberland Pharmaceuticals) is currently recruiting subjects to determine whether ifetroban can improve cardiac function in patients with DMD. Although TPr is a promising therapeutic target for the treatment of dilated cardiomyopathy in DMD, little is known about TPr function in coronary arteries that perfuse blood through the cardiac tissue. In the current study, isolated coronary arteries from young (∼3-5 mo) and aged (∼9-12 mo) mdx mice, a widely used mouse model of DMD, and age-matched controls were examined using wire myography. Vasoconstriction to increasing concentrations of TPr agonist U-46619 (U4) was enhanced in young mdx mice versus controls. In addition, young mdx mice displayed a significant attenuation in endothelial cell-mediated vasodilation to increasing concentrations of the muscarinic agonist acetylcholine (ACh). Since TPr activation was enhanced in young mdx mice, U4-mediated vasoconstriction was measured in the absence and the presence of ifetroban. Ifetroban reduced U4-mediated vasoconstriction in young mdx mice and both aged mdx and control mice. Overall, our data demonstrate enhanced coronary arterial vasoconstriction to TPr activation in young mdx mice, a phenotype that could be reversed with ifetroban. These data could have important therapeutic implications for improving cardiovascular function in DMD.NEW & NOTEWORTHY This investigation revealed 1) impaired acetylcholine-mediated vasodilation, 2) increased U-46619-mediated vasoconstriction, and 3) reversal of the increase in U-46619-mediated vasoconstriction by the thromboxane A2/prostanoid receptor (TPr) antagonist ifetroban in left anterior descending coronary arteries isolated from young mdx mice, a model of Duchenne muscular dystrophy (DMD). Ifetroban has been used in preclinical studies to demonstrate improved cardiac function in mouse models of muscular dystrophy and is currently being investigated in a phase 2 clinical trial in patients with DMD. The current study supports the role of ifetroban in improving coronary artery function in preclinical DMD models, which may contribute to improved cardiovascular health.
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Affiliation(s)
- R Mitchell
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - N E Frederick
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - E R Holzman
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - F Agobe
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - H C M Allaway
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - P Bagher
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
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14
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Hakim MA, Chum PP, Buchholz JN, Behringer EJ. Aging Alters Cerebrovascular Endothelial GPCR and K+ Channel Function: Divergent Role of Biological Sex. J Gerontol A Biol Sci Med Sci 2021; 75:2064-2073. [PMID: 31760422 DOI: 10.1093/gerona/glz275] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Indexed: 12/11/2022] Open
Abstract
Age-related dementia entails impaired blood flow to and throughout the brain due, in part, to reduced endothelial nitric oxide signaling. However, it is unknown whether sex affects cerebrovascular Gq-protein-coupled receptors (GPCRs) and K+ channels underlying endothelium-derived hyperpolarization (EDH) during progressive aging. Thus, we simultaneously evaluated intracellular Ca2+ ([Ca2+]i) and membrane potential (Vm) of intact endothelial tubes freshly isolated from posterior cerebral arteries of young (4-6 mo), middle-aged (12-16 mo), and old (24-28 mo) male and female C57BL/6 mice. Purinergic receptor function (vs. muscarinic) was dominant and enhanced for [Ca2+]i increases in old females versus old males. However, Ca2+-sensitive K+ channel function as defined by NS309-evoked Vm hyperpolarization was mildly impaired in females versus males during old age. This sex-based contrast in declined function of GPCRs and K+ channels to produce EDH may support a greater ability for physiological endothelial GPCR function to maintain optimal cerebral blood flow in females versus males during old age. As reflective of the pattern of cerebral blood flow decline in human subjects, inward-rectifying K+ (KIR) channel function decreased with progressive age regardless of sex. Combined age-related analyses masked male versus female aging and, contrary to expectation, hydrogen peroxide played a minimal role. Altogether, we conclude a sex-based divergence in cerebrovascular endothelial GPCR and K+ channel function while highlighting a previously unidentified form of age-related endothelial dysfunction as reduced KIR channel function.
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Affiliation(s)
- Md A Hakim
- Basic Sciences, Loma Linda University, California
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15
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Gorshkova OP. Age-Related Changes in the Role of
Potassium Channels in Acetylcholine-Induced Dilation of Pial Arteries in Normotensive
and Spontaneously Hypertensive Rats. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021010051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Song MS, Sim HJ, Kang S, Park S, Seo K, Lee SY. Pharmacological inhibition of Kv3 on oxidative stress-induced cataract progression. Biochem Biophys Res Commun 2020; 533:1255-1261. [PMID: 33066958 DOI: 10.1016/j.bbrc.2020.09.138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 09/30/2020] [Indexed: 02/02/2023]
Abstract
Oxidative stress is one of the most important risk factors for cataractogenesis. Previous studies have indicated that BDS-II, a Kv3 channel blocker, plays pivotal roles in oxidative stress-related diseases. This study demonstrates that BDS-II exerts a protective effect on cataractogenesis. Specifically, BDS-II was observed to inhibit lens opacity induced by H2O2. BDS-II was also determined to inhibit cataract progression in a sodium selenite-induced in vivo cataract model by inhibiting reduction of the total GSH. In addition, BDS-II was demonstrated to protect human lens epithelial cells against H2O2-induced cell death. Our results suggest that BDS-II is a potential pharmacological candidate in cataract therapy.
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Affiliation(s)
- Min Seok Song
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, Republic of Korea
| | - Hun Ju Sim
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, Republic of Korea
| | - Seonmi Kang
- Department of Veterinary Clinical Sciences and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sangwan Park
- Department of Veterinary Clinical Sciences and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Kangmoon Seo
- Department of Veterinary Clinical Sciences and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, Republic of Korea.
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17
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Wilson C, Zhang X, Lee MD, MacDonald M, Heathcote HR, Alorfi NMN, Buckley C, Dolan S, McCarron JG. Disrupted endothelial cell heterogeneity and network organization impair vascular function in prediabetic obesity. Metabolism 2020; 111:154340. [PMID: 32791171 PMCID: PMC7538703 DOI: 10.1016/j.metabol.2020.154340] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/29/2020] [Accepted: 08/04/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Obesity is a major risk factor for diabetes and cardiovascular diseases such as hypertension, heart failure, and stroke. Impaired endothelial function occurs in the earliest stages of obesity and underlies vascular alterations that give rise to cardiovascular disease. However, the mechanisms that link weight gain to endothelial dysfunction are ill-defined. Increasing evidence suggests that endothelial cells are not a population of uniform cells but are highly heterogeneous and are organized as a communicating multicellular network that controls vascular function. PURPOSE To investigate the hypothesis that disrupted endothelial heterogeneity and network-level organization contribute to impaired vascular reactivity in obesity. METHODS AND RESULTS To study obesity-related vascular function without complications associated with diabetes, a state of prediabetic obesity was induced in rats. Small artery diameter recordings confirmed nitric-oxide mediated vasodilator responses were dependent on increases in endothelial calcium levels and were impaired in obese animals. Single-photon imaging revealed a linear relationship between blood vessel relaxation and population-wide calcium responses. Obesity did not alter the slope of this relationship, but impaired calcium responses in the endothelial cell network. The network comprised structural and functional components. The structural architecture, a hexagonal lattice network of connected cells, was unchanged in obesity. The functional network contained sub-populations of clustered specialized agonist-sensing cells from which signals were communicated through the network. In obesity there were fewer but larger clusters of sensory cells and communication path lengths between clusters increased. Communication between neighboring cells was unaltered in obesity. Altered network organization resulted in impaired, population-level calcium signaling and deficient endothelial control of vascular tone. CONCLUSIONS The distribution of cells in the endothelial network is critical in determining overall vascular response. Altered cell heterogeneity and arrangement in obesity decreases endothelial function and provides a novel framework for understanding compromised endothelial function in cardiovascular disease.
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Affiliation(s)
- Calum Wilson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK.
| | - Xun Zhang
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Matthew D Lee
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Margaret MacDonald
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Helen R Heathcote
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Nasser M N Alorfi
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK
| | - Charlotte Buckley
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Sharron Dolan
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK
| | - John G McCarron
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK.
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18
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Abstract
Sleep maintains the function of the entire body through homeostasis. Chronic sleep deprivation (CSD) is a prime health concern in the modern world. Previous reports have shown that CSD has profound negative effects on brain vasculature at both the cellular and molecular levels, and that this is a major cause of cognitive dysfunction and early vascular ageing. However, correlations among sleep deprivation (SD), brain vascular changes and ageing have barely been looked into. This review attempts to correlate the alterations in the levels of major neurotransmitters (acetylcholine, adrenaline, GABA and glutamate) and signalling molecules (Sirt1, PGC1α, FOXO, P66shc, PARP1) in SD and changes in brain vasculature, cognitive dysfunction and early ageing. It also aims to connect SD-induced loss in the number of dendritic spines and their effects on alterations in synaptic plasticity, cognitive disabilities and early vascular ageing based on data available in scientific literature. To the best of our knowledge, this is the first article providing a pathophysiological basis to link SD to brain vascular ageing.
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Abstract
Of the 21 members of the connexin family, 4 (Cx37, Cx40, Cx43, and Cx45) are expressed in the endothelium and/or smooth muscle of intact blood vessels to a variable and dynamically regulated degree. Full-length connexins oligomerize and form channel structures connecting the cytosol of adjacent cells (gap junctions) or the cytosol with the extracellular space (hemichannels). The different connexins vary mainly with regard to length and sequence of their cytosolic COOH-terminal tails. These COOH-terminal parts, which in the case of Cx43 are also translated as independent short isoforms, are involved in various cellular signaling cascades and regulate cell functions. This review focuses on channel-dependent and -independent effects of connexins in vascular cells. Channels play an essential role in coordinating and synchronizing endothelial and smooth muscle activity and in their interplay, in the control of vasomotor actions of blood vessels including endothelial cell reactivity to agonist stimulation, nitric oxide-dependent dilation, and endothelial-derived hyperpolarizing factor-type responses. Further channel-dependent and -independent roles of connexins in blood vessel function range from basic processes of vascular remodeling and angiogenesis to vascular permeability and interactions with leukocytes with the vessel wall. Together, these connexin functions constitute an often underestimated basis for the enormous plasticity of vascular morphology and function enabling the required dynamic adaptation of the vascular system to varying tissue demands.
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Affiliation(s)
- Ulrich Pohl
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany; Biomedical Centre, Cardiovascular Physiology, LMU Munich, Planegg-Martinsried, Germany; German Centre for Cardiovascular Research, Partner Site Munich Heart Alliance, Munich, Germany; and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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20
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Trombetta-Lima M, Krabbendam IE, Dolga AM. Calcium-activated potassium channels: implications for aging and age-related neurodegeneration. Int J Biochem Cell Biol 2020; 123:105748. [PMID: 32353429 DOI: 10.1016/j.biocel.2020.105748] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/11/2020] [Accepted: 04/14/2020] [Indexed: 12/16/2022]
Abstract
Population aging, as well as the handling of age-associated diseases, is a worldwide increasing concern. Among them, Alzheimer's disease stands out as the major cause of dementia culminating in full dependence on other people for basic functions. However, despite numerous efforts, in the last decades, there was no new approved therapeutic drug for the treatment of the disease. Calcium-activated potassium channels have emerged as a potential tool for neuronal protection by modulating intracellular calcium signaling. Their subcellular localization is determinant of their functional effects. When located on the plasma membrane of neuronal cells, they can modulate synaptic function, while their activation at the inner mitochondrial membrane has a neuroprotective potential via the attenuation of mitochondrial reactive oxygen species in conditions of oxidative stress. Here we review the dual role of these channels in the aging phenotype and Alzheimer's disease pathology and discuss their potential use as a therapeutic tool.
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Affiliation(s)
- Marina Trombetta-Lima
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV Groningen, the Netherlands; Medical School, Neurology Department, University of São Paulo (USP), 01246903 São Paulo, Brazil
| | - Inge E Krabbendam
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV Groningen, the Netherlands
| | - Amalia M Dolga
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV Groningen, the Netherlands.
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21
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Preventive Beneficial Effect of an Aqueous Extract of Phyllanthus amarus Schum. and Thonn. (Euphorbiaceae) on DOCA-Salt-Induced Hypertension, Cardiac Hypertrophy and Dysfunction, and Endothelial Dysfunction in Rats. J Cardiovasc Pharmacol 2020; 75:573-583. [PMID: 32187164 DOI: 10.1097/fjc.0000000000000825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This study investigated the preventive effect of an aqueous extract of the whole plant of Phyllanthus amarus (AEPA) on blood pressure, cardiac, and endothelial function in the deoxycorticosterone acetate (DOCA) salt-induced hypertensive rat model. Male Wistar rats were assigned into 5 groups receiving either vehicle (control and DOCA salt), DOCA salt combined with AEPA at 100 or 300 mg/kg, or AEPA (100 mg/kg) alone for 5 weeks. In addition, DOCA salt-treated rats were allowed free access to water containing 1% NaCl. Systolic blood pressure, left ventricle parameters, vascular reactivity of primary mesenteric artery rings, the vascular level of oxidative stress, and the level of target proteins were determined, using respectively tail-cuff sphygmomanometry, echocardiography, organ chambers, dihydroethidium staining, and immunofluorescence methods. After 5 weeks, AEPA treatments (100 or 300 mg/kg per day) significantly prevented the increase in systolic blood pressure in DOCA salt-treated rats, respectively, by about 24 and 21 mm Hg, improved cardiac diastolic function, and reduced significantly the increased posterior and septum diastolic wall thickness and the left ventricle mass in hypertensive rats. Moreover, the DOCA salt-induced endothelial dysfunction and the blunted nitric oxide- and endothelium-dependent hyperpolarization-mediated relaxations in primary mesenteric artery were improved after the AEPA treatments. AEPA also reduced the level of vascular oxidative stress and the expression level of target proteins (eNOS, COX-2, NADPH oxidase subunit p22) in DOCA salt rats. Altogether, AEPA prevented hypertension, improved cardiac structure and function, and improved endothelial function in DOCA salt rats. Such beneficial effects seem to be related, at least in part, to normalization of the vascular level of oxidative stress.
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22
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Farooq MA, Gaertner S, Amoura L, Niazi ZR, Park SH, Qureshi AW, Oak MH, Toti F, Schini-Kerth VB, Auger C. Intake of omega-3 formulation EPA:DHA 6:1 by old rats for 2 weeks improved endothelium-dependent relaxations and normalized the expression level of ACE/AT1R/NADPH oxidase and the formation of ROS in the mesenteric artery. Biochem Pharmacol 2019; 173:113749. [PMID: 31830469 DOI: 10.1016/j.bcp.2019.113749] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 12/06/2019] [Indexed: 01/21/2023]
Abstract
Omega-3 polyunsaturated fatty acids (PUFAs) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to protect the cardiovascular system, in part, by stimulating the endothelial formation of nitric oxide (NO). EPA:DHA 6:1 has been identified as a potent omega 3 PUFA formulation to induce endothelium-dependent vasorelaxation and activation of endothelial NO synthase (eNOS). This study examined whether intake of EPA:DHA 6:1 (500 mg/kg/day) for 2 weeks improves an established endothelial dysfunction in old rats (20 months old), and, if so, the underlying mechanism was subsequently determined. In the main mesenteric artery rings, an endothelial dysfunction characterized by a blunted NO component, an abolished endothelium-dependent hyperpolarization component, and increased endothelium-dependent contractile responses (EDCFs) are observed in old rats compared to young rats. Age-related endothelial dysfunction was associated with increased vascular formation of reactive oxygen species (ROS) and expression of eNOS, components of the local angiotensin system, senescence markers, and cyclooxygenase-2 (COX-2), and the downregulation of COX-1. The EPA:DHA 6:1 treatment improved the NO-mediated relaxation, reduced the EDCF-dependent contractile response and the vascular formation of ROS, and normalized the expression level of all target proteins in the old arterial wall. Thus, the present findings indicate that a 2-week intake of EPA:DHA 6:1 by old rats restored endothelium-dependent NO-mediated relaxations, most likely, by preventing the upregulation of the local angiotensin system and the subsequent formation of ROS.
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Affiliation(s)
- Muhammad A Farooq
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Université de Strasbourg, Faculté de Pharmacie, 67000 Strasbourg, France
| | - Sébastien Gaertner
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Hôpitaux Universitaire de Strasbourg (HUS), Service des Maladies Vasculaires - Hypertension Artérielle, 67000 Strasbourg, France
| | - Lamia Amoura
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Université de Strasbourg, Faculté de Pharmacie, 67000 Strasbourg, France
| | - Zahid R Niazi
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Université de Strasbourg, Faculté de Pharmacie, 67000 Strasbourg, France
| | - Sin-Hee Park
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Université de Strasbourg, Faculté de Pharmacie, 67000 Strasbourg, France
| | - Abdul W Qureshi
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Université de Strasbourg, Faculté de Pharmacie, 67000 Strasbourg, France
| | - Min-Ho Oak
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Université de Strasbourg, Faculté de Pharmacie, 67000 Strasbourg, France
| | - Florence Toti
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Université de Strasbourg, Faculté de Pharmacie, 67000 Strasbourg, France
| | - Valérie B Schini-Kerth
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Université de Strasbourg, Faculté de Pharmacie, 67000 Strasbourg, France; Hôpitaux Universitaire de Strasbourg (HUS), Service des Maladies Vasculaires - Hypertension Artérielle, 67000 Strasbourg, France
| | - Cyril Auger
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, 67000 Strasbourg, France; Université de Strasbourg, Faculté de Pharmacie, 67000 Strasbourg, France.
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Behringer EJ, Hakim MA. Functional Interaction among K Ca and TRP Channels for Cardiovascular Physiology: Modern Perspectives on Aging and Chronic Disease. Int J Mol Sci 2019; 20:ijms20061380. [PMID: 30893836 PMCID: PMC6471369 DOI: 10.3390/ijms20061380] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/07/2019] [Accepted: 03/15/2019] [Indexed: 12/16/2022] Open
Abstract
Effective delivery of oxygen and essential nutrients to vital organs and tissues throughout the body requires adequate blood flow supplied through resistance vessels. The intimate relationship between intracellular calcium ([Ca2+]i) and regulation of membrane potential (Vm) is indispensable for maintaining blood flow regulation. In particular, Ca2+-activated K+ (KCa) channels were ascertained as transducers of elevated [Ca2+]i signals into hyperpolarization of Vm as a pathway for decreasing vascular resistance, thereby enhancing blood flow. Recent evidence also supports the reverse role for KCa channels, in which they facilitate Ca2+ influx into the cell interior through open non-selective cation (e.g., transient receptor potential; TRP) channels in accord with robust electrical (hyperpolarization) and concentration (~20,000-fold) transmembrane gradients for Ca2+. Such an arrangement supports a feed-forward activation of Vm hyperpolarization while potentially boosting production of nitric oxide. Furthermore, in vascular types expressing TRP channels but deficient in functional KCa channels (e.g., collecting lymphatic endothelium), there are profound alterations such as downstream depolarizing ionic fluxes and the absence of dynamic hyperpolarizing events. Altogether, this review is a refined set of evidence-based perspectives focused on the role of the endothelial KCa and TRP channels throughout multiple experimental animal models and vascular types. We discuss the diverse interactions among KCa and TRP channels to integrate Ca2+, oxidative, and electrical signaling in the context of cardiovascular physiology and pathology. Building from a foundation of cellular biophysical data throughout a wide and diverse compilation of significant discoveries, a translational narrative is provided for readers toward the treatment and prevention of chronic, age-related cardiovascular disease.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, 11041 Campus Street, Risley Hall, Loma Linda University, Loma Linda, CA 92350, USA.
| | - Md A Hakim
- Department of Basic Sciences, 11041 Campus Street, Risley Hall, Loma Linda University, Loma Linda, CA 92350, USA.
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Pogoda K, Kameritsch P, Mannell H, Pohl U. Connexins in the control of vasomotor function. Acta Physiol (Oxf) 2019; 225:e13108. [PMID: 29858558 DOI: 10.1111/apha.13108] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 12/13/2022]
Abstract
Vascular endothelial cells, as well as smooth muscle cells, show heterogeneity with regard to their receptor expression and reactivity. For the vascular wall to act as a functional unit, the various cells' responses require integration. Such an integration is not only required for a homogeneous response of the vascular wall, but also for the vasomotor behaviour of consecutive segments of the microvascular arteriolar tree. As flow resistances of individual sections are connected in series, sections require synchronization and coordination to allow effective changes of conductivity and blood flow. A prerequisite for the local coordination of individual vascular cells and different sections of an arteriolar tree is intercellular communication. Connexins are involved in a dual manner in this coordination. (i) By forming gap junctions between cells, they allow an intercellular exchange of signalling molecules and electrical currents. In particular, the spread of electrical currents allows for coordination of cell responses over longer distances. (ii) Connexins are able to interact with other proteins to form signalling complexes. In this way, they can modulate and integrate individual cells' responses also in a channel-independent manner. This review outlines mechanisms allowing the vascular connexins to exert their coordinating function and to regulate the vasomotor reactions of blood vessels both locally, and in vascular networks. Wherever possible, we focus on the vasomotor behaviour of small vessels and arterioles which are the main vessels determining vascular resistance, blood pressure and local blood flow.
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Affiliation(s)
- K. Pogoda
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - P. Kameritsch
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - H. Mannell
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
| | - U. Pohl
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
- Munich Cluster for Systems Neurology (SyNergy); Munich Germany
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25
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Socha MJ, Segal SS. Microvascular mechanisms limiting skeletal muscle blood flow with advancing age. J Appl Physiol (1985) 2018; 125:1851-1859. [PMID: 30412030 PMCID: PMC6737458 DOI: 10.1152/japplphysiol.00113.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 10/22/2018] [Accepted: 11/06/2018] [Indexed: 02/08/2023] Open
Abstract
Effective oxygen delivery to active muscle fibers requires that vasodilation initiated in distal arterioles, which control flow distribution and capillary perfusion, ascends the resistance network into proximal arterioles and feed arteries, which govern total blood flow into the muscle. With exercise onset, ascending vasodilation reflects initiation and conduction of hyperpolarization along endothelium from arterioles into feed arteries. Electrical coupling of endothelial cells to smooth muscle cells evokes the rapid component of ascending vasodilation, which is sustained by ensuing release of nitric oxide during elevated luminal shear stress. Concomitant sympathetic neural activation inhibits ascending vasodilation by stimulating α-adrenoreceptors on smooth muscle cells to constrict the resistance vasculature. We hypothesized that compromised muscle blood flow in advanced age reflects impaired ascending vasodilation through actions on both cell layers of the resistance network. In the gluteus maximus muscle of old (24 mo) vs. young (4 mo) male mice (corresponding to mid-60s vs. early 20s in humans) inhibition of α-adrenoreceptors in old mice restored ascending vasodilation, whereas even minimal activation of α-adrenoreceptors in young mice attenuated ascending vasodilation in the manner seen with aging. Conduction of hyperpolarization along the endothelium is impaired in old vs. young mice because of "leaky" membranes resulting from the activation of potassium channels by hydrogen peroxide released from endothelial cells. Exposing the endothelium of young mice to hydrogen peroxide recapitulates this effect of aging. Thus enhanced α-adrenoreceptor activation of smooth muscle in concert with electrically leaky endothelium restricts muscle blood flow by impairing ascending vasodilation in advanced age.
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Affiliation(s)
- Matthew J Socha
- Biology Department, University of Scranton , Scranton, Pennsylvania
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri , Columbia, Missouri
- Dalton Cardiovascular Research Center , Columbia, Missouri
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Terwoord JD, Hearon CM, Luckasen GJ, Richards JC, Joyner MJ, Dinenno FA. Elevated extracellular potassium prior to muscle contraction reduces onset and steady-state exercise hyperemia in humans. J Appl Physiol (1985) 2018; 125:615-623. [PMID: 29722620 DOI: 10.1152/japplphysiol.00183.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The increase in interstitial potassium (K+) during muscle contractions is thought to be a vasodilatory signal that contributes to exercise hyperemia. To determine the role of extracellular K+ in exercise hyperemia, we perfused skeletal muscle with K+ before contractions, such that the effect of any endogenously-released K+ would be minimized. We tested the hypothesis that local, intra-arterial infusion of potassium chloride (KCl) at rest would impair vasodilation in response to subsequent rhythmic handgrip exercise in humans. In 11 young adults, we determined forearm blood flow (FBF) (Doppler ultrasound) and forearm vascular conductance (FVC) (FBF/mean arterial pressure) during 4 min of rhythmic handgrip exercise at 10% of maximal voluntary contraction during 1) control conditions, 2) infusion of KCl before the initiation of exercise, and 3) infusion of sodium nitroprusside (SNP) as a control vasodilator. Infusion of KCl or SNP elevated resting FVC similarly before the onset of exercise (control: 39 ± 6 vs. KCl: 81 ± 12 and SNP: 82 ± 13 ml·min-1·100 mmHg-1; both P < 0.05 vs. control). Infusion of KCl at rest diminished the hyperemic (ΔFBF) and vasodilatory (ΔFVC) response to subsequent exercise by 22 ± 5% and 30 ± 5%, respectively (both P < 0.05 vs. control), whereas SNP did not affect the change in FBF ( P = 0.74 vs. control) or FVC ( P = 0.61 vs. control) from rest to steady-state exercise. These findings implicate the K+ ion as an essential vasodilator substance contributing to exercise hyperemia in humans. NEW & NOTEWORTHY Our findings support a significant and obligatory role for potassium signaling in the local vasodilatory and hyperemic response to exercise in humans.
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Affiliation(s)
- Janée D Terwoord
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University , Fort Collins, Colorado
| | - Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University , Fort Collins, Colorado.,Institute for Exercise and Environmental Medicine, University of Texas Southwestern Medical Center , Dallas, Texas
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, Colorado
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University , Fort Collins, Colorado
| | - Michael J Joyner
- Department of Anesthesiology, Mayo Clinic , Rochester, Minnesota
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University , Fort Collins, Colorado
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Boerman EM, Sen S, Shaw RL, Joshi T, Segal SS. Gene expression profiles of ion channels and receptors in mouse resistance arteries: Effects of cell type, vascular bed, and age. Microcirculation 2018; 25:e12452. [PMID: 29577514 PMCID: PMC5949082 DOI: 10.1111/micc.12452] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 03/19/2018] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Receptors and ion channels of smooth muscle cells (SMCs) and endothelial cells (ECs) are integral to the regulation of vessel diameter and tissue blood flow. Physiological roles of ion channels and receptors in skeletal muscle and mesenteric arteries have been identified; however, their gene expression profiles are undefined. We tested the hypothesis that expression profiles for ion channels and receptors governing vascular reactivity vary with cell type, vascular bed, and age. METHODS Mesenteric and superior epigastric arteries were dissected from Old (24-26 months) and Young (3-6 months) C57BL/6J mice. ECs and SMCs were collected for analysis with custom qRT-PCR arrays to determine expression profiles of 80 ion channel and receptor genes. Bioinformatics analyses were applied to gain insight into functional interactions. RESULTS We identified 68 differences in gene expression with respect to cell type, vessel type, and age. Heat maps illustrate differential expression, and distance matrices predict patterns of coexpression. Gene networks based upon protein-protein interaction datasets and KEGG pathways illustrate biological processes affected by specific differences in gene expression. CONCLUSIONS Differences in gene expression profiles are most pronounced between microvascular ECs and SMCs with subtle variations between vascular beds and age groups.
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Affiliation(s)
- Erika M. Boerman
- Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212
| | - Sidharth Sen
- MU Informatics Institute, University of Missouri, Columbia, MO 65211
| | - Rebecca L. Shaw
- Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212
| | - Trupti Joshi
- MU Informatics Institute, University of Missouri, Columbia, MO 65211
- Health Management and Informatics and Office of Research, School of Medicine, University of Missouri, Columbia, MO 65212
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - Steven S. Segal
- Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212
- Dalton Cardiovascular Research Center, Columbia, MO 65211
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Hakim MA, Buchholz JN, Behringer EJ. Electrical dynamics of isolated cerebral and skeletal muscle endothelial tubes: Differential roles of G-protein-coupled receptors and K + channels. Pharmacol Res Perspect 2018; 6:e00391. [PMID: 29636977 PMCID: PMC5889193 DOI: 10.1002/prp2.391] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/12/2018] [Indexed: 12/13/2022] Open
Abstract
Electrical dynamics of freshly isolated cerebral endothelium have not been determined independently of perivascular nerves and smooth muscle. We tested the hypothesis that endothelium of cerebral and skeletal muscle arteries differentially utilizes purinergic and muscarinic signaling pathways to activate endothelium‐derived hyperpolarization. Changes in membrane potential (Vm) were recorded in intact endothelial tubes freshly isolated from posterior cerebral and superior epigastric arteries of male and female C57BL/6 mice (age: 3‐8 months). Vm was measured in response to activation of purinergic (P2Y) and muscarinic (M3) receptors in addition to small‐ and intermediate‐conductance Ca2+‐activated K+ (SKCa/IKCa) and inward rectifying K+ (KIR) channels using ATP (100 μmol·L−1), acetylcholine (ACh; 10 μmol·L−1), NS309 (0.01‐10 μmol·L−1), and 15 mmol·L−1 KCl, respectively. Intercellular coupling was demonstrated via transfer of propidium iodide dye and electrical current (±0.5‐3 nA) through gap junctions. With similarities observed across gender, peak hyperpolarization to ATP and ACh in skeletal muscle endothelial tubes was ~twofold and ~sevenfold higher, respectively, vs cerebral endothelial tubes, whereas responses to NS309 were similar (from resting Vm ~−30 mV to maximum ~−80 mV). Hyperpolarization (~8 mV) occurred during 15 mmol·L−1 KCl treatment in cerebral but not skeletal muscle endothelial tubes. Despite weaker hyperpolarization during endothelial GPCR stimulation in cerebral vs skeletal muscle endothelium, the capability for robust SKCa/IKCa activity is preserved across brain and skeletal muscle. As vascular reactivity decreases with aging and cardiovascular disease, endothelial K+ channel activity may be calibrated to restore blood flow to respective organs regardless of gender.
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Affiliation(s)
- Md A Hakim
- Basic Sciences Loma Linda University Loma Linda CA USA
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29
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Carvajal FJ, Mira RG, Rovegno M, Minniti AN, Cerpa W. Age-related NMDA signaling alterations in SOD2 deficient mice. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2010-2020. [PMID: 29577983 DOI: 10.1016/j.bbadis.2018.03.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 12/23/2022]
Abstract
Oxidative stress affects the survival and function of neurons. Hence, they have a complex and highly regulated machinery to handle oxidative changes. The dysregulation of this antioxidant machinery is associated with a wide range of neurodegenerative conditions. Therefore, we evaluated signaling alterations, synaptic properties and behavioral performance in 2 and 6-month-old heterozygous manganese superoxide dismutase knockout mice (SOD2+/- mice). We found that their low antioxidant capacity generated direct oxidative damage in proteins, lipids, and DNA. However, only 6-month-old heterozygous knockout mice presented behavioral impairments. On the other hand, synaptic plasticity, synaptic strength and NMDA receptor (NMDAR) dependent postsynaptic potentials were decreased in an age-dependent manner. We also analyzed the phosphorylation state of the NMDAR subunit GluN2B. We found that while the levels of GluN2B phosphorylated on tyrosine 1472 (synaptic form) remain unchanged, we detected increased levels of GluN2B phosphorylated on tyrosine 1336 (extrasynaptic form), establishing alterations in the synaptic/extrasynaptic ratio of GluN2B. Additionally, we found increased levels of two phosphatases associated with dephosphorylation of p-1472: striatal-enriched protein tyrosine phosphatase (STEP) and phosphatase and tensin homolog deleted on chromosome Ten (PTEN). Moreover, we found decreased levels of p-CREB, a master transcription factor activated by synaptic stimulation. In summary, we describe mechanisms by which glutamatergic synapses are altered under oxidative stress conditions. Our results uncovered new putative therapeutic targets for conditions where NMDAR downstream signaling is altered. This work also contributes to our understanding of processes such as synapse formation, learning, and memory in neuropathological conditions.
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Affiliation(s)
- Francisco J Carvajal
- Laboratorio de Función y Patología Neuronal, Santiago, Chile; Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Santiago, Chile; Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rodrigo G Mira
- Laboratorio de Función y Patología Neuronal, Santiago, Chile; Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Santiago, Chile; Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Maximiliano Rovegno
- Departamento de Medicina Intensiva, Facultad de Medicina, Santiago, Chile; Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alicia N Minniti
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Santiago, Chile; Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Waldo Cerpa
- Laboratorio de Función y Patología Neuronal, Santiago, Chile; Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Santiago, Chile; Pontificia Universidad Católica de Chile, Santiago, Chile.
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Behringer EJ. Calcium and electrical signaling in arterial endothelial tubes: New insights into cellular physiology and cardiovascular function. Microcirculation 2018; 24. [PMID: 27801542 DOI: 10.1111/micc.12328] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/25/2016] [Indexed: 12/23/2022]
Abstract
The integral role of the endothelium during the coordination of blood flow throughout vascular resistance networks has been recognized for several decades now. Early examination of the distinct anatomy and physiology of the endothelium as a signaling conduit along the vascular wall has prompted development and application of an intact endothelial "tube" study model isolated from rodent skeletal muscle resistance arteries. Vasodilatory signals such as increased endothelial cell (EC) Ca2+ ([Ca2+ ]i ) and hyperpolarization take place in single ECs while shared between electrically coupled ECs through gap junctions up to distances of millimeters (≥2 mm). The small- and intermediate-conductance Ca2+ activated K+ (SKCa /IKCa or KCa 2.3/KCa 3.1) channels function at the interface of Ca2+ signaling and hyperpolarization; a bidirectional relationship whereby increases in [Ca2+ ]i activate SKCa /IKCa channels to produce hyperpolarization and vice versa. Further, the spatial domain of hyperpolarization among electrically coupled ECs can be finely tuned via incremental modulation of SKCa /IKCa channels to balance the strength of local and conducted electrical signals underlying vasomotor activity. Multifunctional properties of the voltage-insensitive SKCa /IKCa channels of resistance artery endothelium may be employed for therapy during the aging process and development of vascular disease.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, Loma Linda University, Loma Linda, CA, USA
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31
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Lemmey HAL, Ye X, Ding HC, Triggle CR, Garland CJ, Dora KA. Hyperglycaemia disrupts conducted vasodilation in the resistance vasculature of db/db mice. Vascul Pharmacol 2018; 103-105:29-35. [PMID: 29339138 PMCID: PMC5906692 DOI: 10.1016/j.vph.2018.01.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 11/27/2017] [Accepted: 01/10/2018] [Indexed: 11/17/2022]
Abstract
Vascular dysfunction in small resistance arteries is observed during chronic elevations in blood glucose. Hyperglycaemia-associated effects on endothelium-dependent vasodilation have been well characterized, but effects on conducted vasodilation in the resistance vasculature are not known. Small mesenteric arteries were isolated from healthy and diabetic db/db mice, which were used as a model of chronic hyperglycaemia. Endothelium-dependent vasodilation via the Gq/11-coupled proteinase activated receptor 2 (PAR2) was stimulated with the selective agonist SLIGRL. The Ca2+-sensitive fluorescent indicator fluo-8 reported changes in endothelial cell (EC) [Ca2+]i, and triple cannulated bifurcating mesenteric arteries were used to study conducted vasodilation. Chronic hyperglycaemia did not affect either EC Ca2+ or local vasodilation to SLIGRL. However, both acute and chronic exposure to high glucose or the mannitol osmotic control attenuated conducted vasodilation to 10μM SLIGRL. This investigation demonstrates for the first time that a hypertonic solution containing glucose or mannitol can interfere with the spread of a hyperpolarizing current along the endothelium in a physiological setting. Our findings reiterate the importance of studying the effects of hyperglycaemia in the vasculature, and provide the basis for further studies regarding the modulation of junctional proteins involved in cell to cell communication by diseases such as diabetes.
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Affiliation(s)
- Hamish A L Lemmey
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
| | - Xi Ye
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
| | - Hong C Ding
- Department of Pharmacology, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar.
| | - Christopher R Triggle
- Department of Pharmacology, Weill Cornell Medicine in Qatar, P.O. Box 24144, Education City, Doha, Qatar.
| | - Christopher J Garland
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
| | - Kim A Dora
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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Mathew John C, Khaddaj Mallat R, George G, Kim T, Mishra RC, Braun AP. Pharmacologic targeting of endothelial Ca 2+-activated K + channels: A strategy to improve cardiovascular function. Channels (Austin) 2018; 12:126-136. [PMID: 29577810 PMCID: PMC5972810 DOI: 10.1080/19336950.2018.1454814] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 03/15/2018] [Indexed: 12/17/2022] Open
Abstract
Endothelial small and intermediate-conductance, Ca2+-activated K+ channels (KCa2.3 and KCa3.1, respectively) play an important role in the regulation of vascular function and systemic blood pressure. Growing evidence indicates that they are intimately involved in agonist-evoked vasodilation of small resistance arteries throughout the circulation. Small molecule activators of KCa2.x and 3.1 channels, such as SKA-31, can acutely inhibit myogenic tone in isolated resistance arteries, induce effective vasodilation in intact vascular beds, such as the coronary circulation, and acutely decrease systemic blood pressure in vivo. The blood pressure-lowering effect of SKA-31, and early indications of improvement in endothelial dysfunction suggest that endothelial KCa channel activators could eventually be developed into a new class of endothelial targeted agents to combat hypertension or atherosclerosis. This review summarises recent insights into the activation of endothelial Ca2+ activated K+ channels in various vascular beds, and how tools, such as SKA-31, may be beneficial in disease-related conditions.
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Affiliation(s)
- Cini Mathew John
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Rayan Khaddaj Mallat
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Grace George
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Taeyeob Kim
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ramesh C. Mishra
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrew P. Braun
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Behringer EJ, Segal SS. Impact of Aging on Calcium Signaling and Membrane Potential in Endothelium of Resistance Arteries: A Role for Mitochondria. J Gerontol A Biol Sci Med Sci 2017; 72:1627-1637. [PMID: 28510636 DOI: 10.1093/gerona/glx079] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/21/2017] [Indexed: 12/20/2022] Open
Abstract
Impaired blood flow to peripheral tissues during advanced age is associated with endothelial dysfunction and diminished bioavailability of nitric oxide (NO). However, it is unknown whether aging impacts coupling between intracellular calcium ([Ca2+]i) signaling and small- and intermediate K+ channel (SKCa/IKCa) activity during endothelium-derived hyperpolarization (EDH), a signaling pathway integral to dilation of the resistance vasculature. To address the potential impact of aging on EDH, Fura-2 photometry and intracellular recording were applied to evaluate [Ca2+]i and membrane potential of intact endothelial tubes (width, 60 µm; length, 1-3 mm) freshly isolated from superior epigastric arteries of young (4-6 mo) and old (24-26 mo) male C57BL/6 mice. In response to acetylcholine, intracellular release of Ca2+ from the endoplasmic reticulum (ER) was enhanced with aging. Further, treatment with the mitochondrial uncoupler FCCP evoked a significant increase of [Ca2+]i with membrane hyperpolarization in an SKCa/IKCa-dependent manner in the endothelium of old but not young mice. We conclude that the ability of resistance artery endothelium to release Ca2+ from intracellular stores (ie, ER and mitochondria) and hyperpolarize Vm via SKCa/IKCa activation is augmented as compensation for reduced NO bioavailability during advanced age.
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Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, Loma Linda University, California.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia.,Dalton Cardiovascular Research Center, Columbia, Missouri
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Sinkler SY, Segal SS. Rapid versus slow ascending vasodilatation: intercellular conduction versus flow-mediated signalling with tetanic versus rhythmic muscle contractions. J Physiol 2017; 595:7149-7165. [PMID: 28981145 DOI: 10.1113/jp275186] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 09/28/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS In response to exercise, vasodilatation ascends from downstream arterioles into upstream feed arteries (FAs). We hypothesized that the signalling events underlying ascending vasodilatation variy with the intensity and duration of skeletal muscle contraction. In the gluteus maximus muscle of C57BL/6 mice, brief tetanic contraction evoked rapid onset vasodilatation (ROV) (<1 s) throughout the resistance network. Selective damage to endothelium midway between FAs and primary arterioles eliminated ROV only in FAs. Blocking SKCa and IKCa channels attenuated ROV, implicating hyperpolarization as the underlying signal. During rhythmic twitch contractions, slow onset vasodilatation (10-15 s) in FAs remained intact following loss of ROV and was eliminated following nitric oxide synthase inhibition. Tetanic contraction initiates hyperpolarization that conducts along endothelium into FAs. Rhythmic twitch contractions stimulate FA endothelium to release nitric oxide in response to elevated shear stress secondary to metabolic dilatation of arterioles. Complementary endothelial signalling pathways for ascending vasodilatation ensure increased oxygen delivery to active skeletal muscle. ABSTRACT In response to exercise, vasodilatation initiated within the microcirculation of skeletal muscle ascends the resistance network into upstream feed arteries (FAs) located external to the tissue. Ascending vasodilatation (AVD) is essential for reducing FA resistance that otherwise restricts blood flow into the microcirculation. In the present study, we tested the hypothesis that signalling events underlying AVD vary with the intensity and duration of muscle contraction. In the gluteus maximus muscle of anaesthetized male C57BL/6 mice (aged 3-4 months), brief tetanic contraction (100 Hz for 500 ms) evoked rapid onset vasodilatation (ROV) in FAs that peaked within 4 s. By contrast, during rhythmic twitch contractions (4 Hz), slow onset vasodilatation (SOV) of FAs began after ∼10 s and plateaued within 30 s. Selectively damaging the endothelium with light-dye treatment midway between a FA and its primary arteriole eliminated ROV in the FA along with conducted vasodilatation of the FA initiated on the arteriole using ACh microiontophoresis. Superfusion of SKCa and IKCa channel blockers UCL 1684 + TRAM 34 attenuated ROV, implicating endothelial hyperpolarization as the underlying signal. Nevertheless, the SOV of FAs during rhythmic contractions persisted until inhibition of nitric oxide synthase with Nω -nitro-l-arginine methyl ester. Thus, ROV of FAs reflects hyperpolarization of downstream arterioles that conducts along the endothelium into proximal FAs. By contrast, SOV of FAs reflects the local production of nitric oxide by the endothelium in response to luminal shear stress, which increases secondary to arteriolar dilatation downstream. Thus, AVD ensures increased oxygen delivery to active muscle fibres by reducing upstream resistance via complementary signalling pathways that reflect the intensity and duration of muscle contraction.
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Affiliation(s)
- Shenghua Y Sinkler
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA.,Dalton Cardiovascular Research Center, Columbia, MO, USA
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Khaddaj Mallat R, Mathew John C, Kendrick DJ, Braun AP. The vascular endothelium: A regulator of arterial tone and interface for the immune system. Crit Rev Clin Lab Sci 2017; 54:458-470. [PMID: 29084470 DOI: 10.1080/10408363.2017.1394267] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
As the primary interface between the blood and various tissues of the body, the vascular endothelium exhibits a diverse range of roles and activities, all of which contribute to the overall health and function of the cardiovascular system. In this focused review, we discuss several key aspects of endothelial function, how this may be compromised and subsequent consequences. Specifically, we examine the dynamic regulation of arterial contractility and distribution of blood flow through the generation of chemical and electrical signaling events that impinge upon vascular smooth muscle. The endothelium can generate a diverse range of vasoactive compounds and signals, most of which act locally to adjust blood flow in a dynamic fashion to match tissue metabolism. Disruption of these vascular signaling processes (e.g. reduced nitric oxide bioavailability) is typically referred to as endothelial dysfunction, which is a recognized risk factor for cardiovascular disease in patients and occurs early in the development and progression of hypertension, atherosclerosis and tissue ischemia. Endothelial dysfunction is also associated with type-2 Diabetes and aging and increased mechanistic knowledge of the cellular changes contributing to these effects may provide important clues for interventional strategies. The endothelium also serves as the initial site of interaction for immune cells entering tissues in response to damage and acts to facilitate the actions of both the innate and acquired immune systems to interact with the vascular wall. In addition to representing the main cell type responsible for the formation of new blood vessels (i.e. angiogenesis) within the vasculature, the endothelium is also emerging as a source of extracellular vesicle or microparticles for the transport of signaling molecules and other cellular materials to nearby, or remote, sites in the body. The characteristics of released microparticles appear to change with the functional status of the endothelium; thus, these microparticles may represent novel biomarkers of endothelial health and more serious cardiovascular disease.
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Affiliation(s)
- Rayan Khaddaj Mallat
- a Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, and Libin Cardiovascular Institute of Alberta , Calgary , Canada
| | - Cini Mathew John
- a Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, and Libin Cardiovascular Institute of Alberta , Calgary , Canada
| | - Dylan J Kendrick
- a Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, and Libin Cardiovascular Institute of Alberta , Calgary , Canada
| | - Andrew P Braun
- a Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, and Libin Cardiovascular Institute of Alberta , Calgary , Canada
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Welsh DG, Tran CHT, Hald BO, Sancho M. The Conducted Vasomotor Response: Function, Biophysical Basis, and Pharmacological Control. Annu Rev Pharmacol Toxicol 2017; 58:391-410. [PMID: 28968190 DOI: 10.1146/annurev-pharmtox-010617-052623] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Arterial tone is coordinated among vessel segments to optimize nutrient transport and organ function. Coordinated vasomotor activity is remarkable to observe and depends on stimuli, sparsely generated in tissue, eliciting electrical responses that conduct lengthwise among electrically coupled vascular cells. The conducted response is the focus of this topical review, and in this regard, the authors highlight literature that advances an appreciation of functional significance, cellular mechanisms, and biophysical principles. Of particular note, this review stresses that conduction is enabled by a defined pattern of charge movement along the arterial wall as set by three key parameters (tissue structure, gap junctional resistivity, and ion channel activity). The impact of disease on conduction is carefully discussed, as are potential strategies to restore this key biological response and, along with it, the match of blood flow delivery with tissue energetic demand.
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Affiliation(s)
- Donald G Welsh
- Robarts Research Institute, Department of Physiology and Pharmacology, Schulich School of Medicine, University of Western Ontario, London, Ontario N6A 5B7, Canada;
| | - Cam Ha T Tran
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Bjorn O Hald
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Maria Sancho
- Robarts Research Institute, Department of Physiology and Pharmacology, Schulich School of Medicine, University of Western Ontario, London, Ontario N6A 5B7, Canada;
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EPA:DHA 6:1 prevents angiotensin II-induced hypertension and endothelial dysfunction in rats: role of NADPH oxidase- and COX-derived oxidative stress. Hypertens Res 2017; 40:966-975. [DOI: 10.1038/hr.2017.72] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 06/16/2017] [Accepted: 06/30/2017] [Indexed: 12/19/2022]
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Félétou M, Vanhoutte PM. Endothelium-dependent hyperpolarizations: Quo vadis? Acta Physiol (Oxf) 2017; 219:100-107. [PMID: 26820582 DOI: 10.1111/apha.12657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- M. Félétou
- Institut de Recherches Servier; Suresnes France
- Li Ka Shing Faculty of Medicine; Hong Kong China
| | - P. M. Vanhoutte
- Institut de Recherches Servier; Suresnes France
- Li Ka Shing Faculty of Medicine; Hong Kong China
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Choi S, Kim JA, Li H, Shin K, Oh GT, Lee Y, Oh S, Pewzner‐Jung Y, Futerman AH, Suh SH. KCa 3.1 upregulation preserves endothelium-dependent vasorelaxation during aging and oxidative stress. Aging Cell 2016; 15:801-10. [PMID: 27363720 PMCID: PMC5013018 DOI: 10.1111/acel.12502] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2016] [Indexed: 01/24/2023] Open
Abstract
Endothelial oxidative stress develops with aging and reactive oxygen species impair endothelium-dependent relaxation (EDR) by decreasing nitric oxide (NO) availability. Endothelial KCa 3.1, which contributes to EDR, is upregulated by H2 O2 . We investigated whether KCa 3.1 upregulation compensates for diminished EDR to NO during aging-related oxidative stress. Previous studies identified that the levels of ceramide synthase 5 (CerS5), sphingosine, and sphingosine 1-phosphate were increased in aged wild-type and CerS2 mice. In primary mouse aortic endothelial cells (MAECs) from aged wild-type and CerS2 null mice, superoxide dismutase (SOD) was upregulated, and catalase and glutathione peroxidase 1 (GPX1) were downregulated, when compared to MAECs from young and age-matched wild-type mice. Increased H2 O2 levels induced Fyn and extracellular signal-regulated kinases (ERKs) phosphorylation and KCa 3.1 upregulation. Catalase/GPX1 double knockout (catalase(-/-) /GPX1(-/-) ) upregulated KCa 3.1 in MAECs. NO production was decreased in aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) MAECs. However, KCa 3.1 activation-induced, N(G) -nitro-l-arginine-, and indomethacin-resistant EDR was increased without a change in acetylcholine-induced EDR in aortic rings from aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) mice. CerS5 transfection or exogenous application of sphingosine or sphingosine 1-phosphate induced similar changes in levels of the antioxidant enzymes and upregulated KCa 3.1. Our findings suggest that, during aging-related oxidative stress, SOD upregulation and downregulation of catalase and GPX1, which occur upon altering the sphingolipid composition or acyl chain length, generate H2 O2 and thereby upregulate KCa 3.1 expression and function via a H2 O2 /Fyn-mediated pathway. Altogether, enhanced KCa 3.1 activity may compensate for decreased NO signaling during vascular aging.
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Affiliation(s)
- Shinkyu Choi
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Ji Aee Kim
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Hai‐yan Li
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Kyong‐Oh Shin
- College of Pharmacy and MRC Chungbuk National University Chongju South Korea
| | - Goo Taeg Oh
- Department of Life Sciences Ewha Womans University Seoul South Korea
| | - Yong‐Moon Lee
- College of Pharmacy and MRC Chungbuk National University Chongju South Korea
| | - Seikwan Oh
- Department of Molecular Medicine Medical School Ewha Womans University Seoul South Korea
| | - Yael Pewzner‐Jung
- Department of Biological Chemistry Weizmann Institute of Science Rehovot Israel
| | - Anthony H. Futerman
- Department of Biological Chemistry Weizmann Institute of Science Rehovot Israel
| | - Suk Hyo Suh
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
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Sinkler SY, Fernando CA, Segal SS. Differential α-adrenergic modulation of rapid onset vasodilatation along resistance networks of skeletal muscle in old versus young mice. J Physiol 2016; 594:6987-7004. [PMID: 27501249 DOI: 10.1113/jp272409] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 07/27/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Rapid onset vasodilatation (ROV) initiates functional hyperaemia upon skeletal muscle contraction and is attenuated during ageing via α-adrenoreceptor (αAR) stimulation, but it is unknown where this effect predominates in resistance networks. In gluteus maximus muscles of young (4 months) and old (24 months) male C57BL/6 mice, tetanic contraction while observing feed arteries and arterioles initiated ROV, which increased with contraction duration, peaked later in upstream versus downstream vessel branches and was attenuated throughout networks with advanced age. With no effect on muscle force production, inhibiting αARs improved ROV in old mice while activating αARs attenuated ROV in young mice. Modulating ROV through αARs was greater in upstream feed arteries and arterioles compared to downstream arterioles, with α2 ARs more effective than α1 ARs. ROV is coordinated along resistance networks and modulated differentially between young and old mice via αARs; with advanced age, attenuated dilatation of upstream branches will restrict muscle blood flow. ABSTRACT Rapid onset vasodilatation (ROV) in skeletal muscle is attenuated during advanced age via α-adrenoreceptor (αAR) activation, but it is unknown where such effects predominate in the resistance vasculature. Studying the gluteus maximus muscle (GM) of anaesthetized young (4 months) and old (24 months) male C57BL/6 mice, we tested the hypothesis that attenuation of ROV during advanced age is most effective in proximal branches of microvascular resistance networks. Diameters of a feed artery (FA) and first- (1A), second- (2A) and third- (3A) order arterioles were studied in response to single tetanic contractions (100 Hz, 100-1000 ms). ROV began within 1 s and peaked sooner in 2A and 3A (∼3 s) than in 1A or FA (∼4 s). Relative amplitudes of dilatation increased with contraction duration and with vessel branch order (FA<1A<2A<3A). In old mice, attenuation of ROV was greater in FA and 1A compared to 2A and 3A. With no effect on muscle force production, inhibiting αARs (phentolamine; 10-6 m) improved ROV in FA and 1A of old mice while subthreshold stimulation of αARs in young mice (noradrenaline; 10-9 m) depressed ROV most effectively in FA and 1A. In young mice, stimulating α1 ARs (phenylephrine; 10-7 m) and α2 ARs (UK 14304; 10-7 m) attenuated ROV primarily in FA. In old mice, inhibiting α2 ARs (rauwolscine; 10-7 m) restored ROV more effectively in FA and 1A than did inhibiting α1 ARs (prazosin; 10-8 m). We conclude that, with temporal and spatial coordination along resistance networks, attenuation of ROV with advanced age is most effective in proximal branches via constitutive activation of α2 ARs.
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Affiliation(s)
- Shenghua Y Sinkler
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA
| | - Charmain A Fernando
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA.,Dalton Cardiovascular Research Center, Columbia, MO, 65211, USA
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Schmidt K, Windler R, de Wit C. Communication Through Gap Junctions in the Endothelium. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 77:209-40. [PMID: 27451099 DOI: 10.1016/bs.apha.2016.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A swarm of fish displays a collective behavior (swarm behavior) and moves "en masse" despite the huge number of individual animals. In analogy, organ function is supported by a huge number of cells that act in an orchestrated fashion and this applies also to vascular cells along the vessel length. It is obvious that communication is required to achieve this vital goal. Gap junctions with their modular bricks, connexins (Cxs), provide channels that interlink the cytosol of adjacent cells by a pore sealed against the extracellular space. This allows the transfer of ions and charge and thereby the travel of membrane potential changes along the vascular wall. The endothelium provides a low-resistance pathway that depends crucially on connexin40 which is required for long-distance conduction of dilator signals in the microcirculation. The experimental evidence for membrane potential changes synchronizing vascular behavior is manifold but the functional verification of a physiologic role is still open. Other molecules may also be exchanged that possibly contribute to the synchronization (eg, Ca(2+)). Recent data suggest that vascular Cxs have more functions than just facilitating communication. As pharmacological tools to modulate gap junctions are lacking, Cx-deficient mice provide currently the standard to unravel their vascular functions. These include arteriolar dilation during functional hyperemia, hypoxic pulmonary vasoconstriction, vascular collateralization after ischemia, and feedback inhibition on renin secretion in the kidney.
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Affiliation(s)
- K Schmidt
- Institut für Physiologie, Universität zu Lübeck, Lübeck, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK) e.V. (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
| | - R Windler
- Institut für Physiologie, Universität zu Lübeck, Lübeck, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK) e.V. (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
| | - C de Wit
- Institut für Physiologie, Universität zu Lübeck, Lübeck, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK) e.V. (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany.
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Sesti F. Oxidation of K(+) Channels in Aging and Neurodegeneration. Aging Dis 2016; 7:130-5. [PMID: 27114846 PMCID: PMC4809605 DOI: 10.14336/ad.2015.0901] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 09/01/2015] [Indexed: 01/26/2023] Open
Abstract
Reversible regulation of proteins by reactive oxygen species (ROS) is an important mechanism of neuronal plasticity. In particular, ROS have been shown to act as modulatory molecules of ion channels-which are key to neuronal excitability-in several physiological processes. However ROS are also fundamental contributors to aging vulnerability. When the level of excess ROS increases in the cell during aging, DNA is damaged, proteins are oxidized, lipids are degraded and more ROS are produced, all culminating in significant cell injury. From this arose the idea that oxidation of ion channels by ROS is one of the culprits for neuronal aging. Aging-dependent oxidative modification of voltage-gated potassium (K(+)) channels was initially demonstrated in the nematode Caenorhabditis elegans and more recently in the mammalian brain. Specifically, oxidation of the delayed rectifier KCNB1 (Kv2.1) and of Ca(2+)- and voltage sensitive K(+) channels have been established suggesting that their redox sensitivity contributes to altered excitability, progression of healthy aging and of neurodegenerative disease. Here I discuss the implications that oxidation of K(+) channels by ROS may have for normal aging, as well as for neurodegenerative disease.
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Affiliation(s)
- Federico Sesti
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854, USA
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Boerman EM, Everhart JE, Segal SS. Advanced age decreases local calcium signaling in endothelium of mouse mesenteric arteries in vivo. Am J Physiol Heart Circ Physiol 2016; 310:H1091-6. [PMID: 26945073 DOI: 10.1152/ajpheart.00038.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 02/29/2016] [Indexed: 11/22/2022]
Abstract
Aging is associated with vascular dysfunction that impairs tissue perfusion, physical activity, and the quality of life. Calcium signaling in endothelial cells (ECs) is integral to vasomotor control, exemplified by localized Ca(2+) signals within EC projections through holes in the internal elastic lamina (IEL). Within these microdomains, endothelium-derived hyperpolarization is integral to smooth muscle cell (SMC) relaxation via coupling through myoendothelial gap junctions. However, the effects of aging on local EC Ca(2+) signals (and thereby signaling between ECs and SMCs) remain unclear, and these events have not been investigated in vivo. Furthermore, it is unknown whether aging affects either the number or the size of IEL holes. In the present study, we tested the hypothesis that local EC Ca(2+) signaling is impaired with advanced age along with a reduction in IEL holes. In anesthetized mice expressing a Ca(2+)-sensitive fluorescent protein (GCaMP2) selectively in ECs, our findings illustrate that for mesenteric arteries controlling splanchnic blood flow the frequency of spontaneous local Ca(2+) signals in ECs was reduced by ∼85% in old (24-26 mo) vs. young (3-6 mo) animals. At the same time, the number (and total area) of holes per square millimeter of IEL was reduced by ∼40%. We suggest that diminished signaling between ECs and SMCs contributes to dysfunction of resistance arteries with advanced age.Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/aging-impairs-endothelial-ca2-signaling/.
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Affiliation(s)
- Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and
| | - Jesse E Everhart
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and Dalton Cardiovascular Research Center, Columbia, Missouri
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Patel R, Sesti F. Oxidation of ion channels in the aging nervous system. Brain Res 2016; 1639:174-85. [PMID: 26947620 DOI: 10.1016/j.brainres.2016.02.046] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 02/24/2016] [Accepted: 02/25/2016] [Indexed: 12/19/2022]
Abstract
Ion channels are integral membrane proteins that allow passive diffusion of ions across membranes. In neurons and in other excitable cells, the harmonious coordination between the numerous types of ion channels shape and propagate electrical signals. Increased accumulation of reactive oxidative species (ROS), and subsequent oxidation of proteins, including ion channels, is a hallmark feature of aging and may contribute to cell failure as a result. In this review we discuss the effects of ROS on three major types of ion channels of the central nervous system, namely the potassium (K(+)), calcium (Ca(2+)) and sodium (Na(+)) channels. We examine two general mechanisms through which ROS affect ion channels: via direct oxidation of specific residues and via indirect interference of pathways that regulate the channels. The overall status of the present studies indicates that the interaction of ion channels with ROS is multimodal and pervasive in the central nervous system and likely constitutes a general mechanism of aging susceptibility.
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Affiliation(s)
- Rahul Patel
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, 683 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Federico Sesti
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, 683 Hoes Lane West, Piscataway, NJ 08854, USA.
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Stead R, Musa MG, Bryant CL, Lanham SA, Johnston DA, Reynolds R, Torrens C, Fraser PA, Clough GF. Developmental conditioning of endothelium-derived hyperpolarizing factor-mediated vasorelaxation. J Hypertens 2016; 34:452-63; discussion 463. [PMID: 26682783 PMCID: PMC4732175 DOI: 10.1097/hjh.0000000000000833] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/26/2015] [Accepted: 11/20/2015] [Indexed: 01/13/2023]
Abstract
OBJECTIVES The endothelium maintains vascular homeostasis through the release of endothelium-derived relaxing factors (EDRF) and endothelium-derived hyperpolarization (EDH). The balance in EDH : EDRF is disturbed in cardiovascular disease and may also be susceptible to developmental conditioning through exposure to an adverse uterine environment to predispose to later risk of hypertension and vascular disease. METHODS Developmentally conditioned changes in EDH : EDRF signalling pathways were investigated in cremaster arterioles (18-32 μm diameter) and third-order mesenteric arteries of adult male mice offspring of dams fed either a fat-rich (high fat, HF, 45% energy from fat) or control (C, 10% energy from fat) diet. After weaning, offspring either continued on high fat or were placed on control diets to give four dietary groups (C/C, HF/C, C/HF, and HF/HF) and studied at 15 weeks of age. RESULTS EDH via intermediate (IKCa) and small (SKca) conductance calcium-activated potassium channels contributed less than 10% to arteriolar acetylcholine-induced relaxation in in-situ conditioned HF/C offspring compared with ∼60% in C/C (P < 0.01). The conditioned reduction in EDH signalling in HF/C offspring was reversed in offspring exposed to a high-fat diet both before and after weaning (HF/HF, 55%, P < 0.01 vs. HF/C). EDH signalling was unaffected in arterioles from C/HF offspring. The changes in EDH : EDRF were associated with altered endothelial cell expression and localization of IKCa channels. CONCLUSION This is the first evidence that EDH-mediated microvascular relaxation is susceptible to an adverse developmental environment through down-regulation of the IKCa signalling pathway. Conditioned offspring exposed to a 'second hit' (HF/HF) exhibit adaptive vascular mechanisms to preserve dilator function.
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Affiliation(s)
- Rebecca Stead
- Vascular Research Group
- Rebecca Stead and Moji G. Musa contributed equally to the writing of this article
| | - Moji G. Musa
- Vascular Research Group
- Rebecca Stead and Moji G. Musa contributed equally to the writing of this article
| | | | - Stuart A. Lanham
- Bone and Joint Research Group, Institute of Developmental Sciences
| | - David A. Johnston
- Faculty of Medicine, Biomedical Imaging Unit, University of Southampton, Southampton
| | | | | | - Paul A. Fraser
- Cardiovascular Division, BHF Centre of Research Excellence, School of Medicine, King's College London, London, United Kingdom
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Segal SS. Integration and Modulation of Intercellular Signaling Underlying Blood Flow Control. J Vasc Res 2015; 52:136-57. [PMID: 26368324 DOI: 10.1159/000439112] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 07/30/2015] [Indexed: 01/25/2023] Open
Abstract
Vascular resistance networks control tissue blood flow in concert with regulating arterial perfusion pressure. In response to increased metabolic demand, vasodilation arising in arteriolar networks ascends to encompass proximal feed arteries. By reducing resistance upstream, ascending vasodilation (AVD) increases blood flow into the microcirculation. Once initiated, e.g. through local activation of K(+) channels in endothelial cells (ECs), hyperpolarization is conducted through gap junctions along the endothelium. Via EC projections through the internal elastic lamina, hyperpolarization spreads into the surrounding smooth-muscle cells (SMCs) through myoendothelial gap junctions (MEGJs) to promote their relaxation. Intercellular signaling through electrical signal transmission (i.e. cell-to-cell conduction) can thereby coordinate vasodilation along and among the branches of microvascular resistance networks. Perivascular sympathetic nerve fibers course through the adventitia and release norepinephrine to stimulate SMCs via α-adrenoreceptors to produce contraction. In turn, SMCs can signal ECs through MEGJs to activate K(+) channels and attenuate sympathetic vasoconstriction. Activation of K(+) channels along the endothelium will dissipate electrical signal transmission and inhibit AVD, thereby restricting blood flow into the microcirculation while maintaining peripheral resistance and perfusion pressure. This review explores the origins and nature of the intercellular signaling that governs blood flow control in skeletal muscle with respect to the interplay between AVD and sympathetic innervation. Whereas these interactions are integral to daily activity and athletic performance, determining the interplay between respective signaling events provides insight into how selective interventions can improve tissue perfusion and oxygen delivery during vascular disease.
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Behringer EJ, Segal SS. Membrane potential governs calcium influx into microvascular endothelium: integral role for muscarinic receptor activation. J Physiol 2015; 593:4531-48. [PMID: 26260126 DOI: 10.1113/jp271102] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/03/2015] [Indexed: 01/12/2023] Open
Abstract
In resistance arteries, coupling a rise of intracellular calcium concentration ([Ca(2+)]i) to endothelial cell hyperpolarization underlies smooth muscle cell relaxation and vasodilatation, thereby increasing tissue blood flow and oxygen delivery. A controversy persists as to whether changes in membrane potential (V(m)) alter endothelial cell [Ca(2+)]i. We tested the hypothesis that V(m) governs [Ca(2+)]i in endothelium of resistance arteries by performing Fura-2 photometry while recording and controlling V(m) of intact endothelial tubes freshly isolated from superior epigastric arteries of C57BL/6 mice. Under resting conditions, [Ca(2+)]i did not change when V(m) shifted from baseline (∼-40 mV) via exposure to 10 μM NS309 (hyperpolarization to ∼-80 mV), via equilibration with 145 mm [K(+)]o (depolarization to ∼-5 mV), or during intracellular current injection (±0.5 to 5 nA, 20 s pulses) while V(m) changed linearly between ∼-80 mV and +10 mV. In contrast, during the plateau (i.e. Ca(2+) influx) phase of the [Ca(2+)]i response to approximately half-maximal stimulation with 100 nm ACh (∼EC50), [Ca(2+)]i increased as V(m) hyperpolarized below -40 mV and decreased as V(m) depolarized above -40 mV. The magnitude of [Ca(2+)]i reduction during depolarizing current injections correlated with the amplitude of the plateau [Ca(2+)]i response to ACh. The effect of hyperpolarization on [Ca(2+)]i was abolished following removal of extracellular Ca(2+), was enhanced subtly by raising extracellular [Ca(2+)] from 2 mm to 10 mm and was reduced by half in endothelium of TRPV4(-/-) mice. Thus, during submaximal activation of muscarinic receptors, V(m) can modulate Ca(2+) entry through the plasma membrane in accord with the electrochemical driving force.
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Affiliation(s)
- Erik J Behringer
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA.,Dalton Cardiovascular Research Center, Columbia, MO, 65211, USA
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Pries AR, Secomb TW. Making microvascular networks work: angiogenesis, remodeling, and pruning. Physiology (Bethesda) 2015; 29:446-55. [PMID: 25362638 DOI: 10.1152/physiol.00012.2014] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The adequate and efficient functioning of the microcirculation requires not only numerous vessels providing a large surface area for transport but also a structure that provides short diffusion distances from capillaries to tissue and efficient distribution of convective blood flow. Theoretical models show how a combination of angiogenesis, remodeling, and pruning in response to hemodynamic and metabolic stimuli, termed "angioadaptation," generates well organized, functional networks.
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Affiliation(s)
- Axel R Pries
- Department of Physiology and CCR, Charité, Berlin, Germany; Deutsches Herzzentrum Berlin, Berlin, Germany;
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, Arizona
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Hu Z, Ma A, Zhang Y, Xi Y, Fan L, Wang T, Zhang T. Voltage-gated potassium+ channel expression in coronary artery smooth muscle cells of SHR and WKY. Cell Biochem Biophys 2015; 70:1725-31. [PMID: 25030407 DOI: 10.1007/s12013-014-0120-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study aims to compare the expression of genes and the molecular characteristic of voltage-gated K(+) channels, which make great effort in maintaining and controlling smooth muscle contraction, cellular membrane potential, and intracellular calcium ion currents in artery smooth muscle cells of SHR and WKY. Expression of potassium ions family in coronary artery was detected through reverse transcription polymerase chain reaction quantitatively. Significant levels of voltage-gated K(+) channels α1.2, α1.5, and β1.1 expression were all proved to be significantly higher in smooth muscles of SHR than WKY. Whole-cell voltage-gated K(+) channel currents were larger in SHR artery smooth muscles than the ones of WKY. Moreover, the voltage dependence of voltage-gated potassium channel activation was more negative in artery smooth muscle of SHR than that of WKY, while voltage dependence of availability was not different. The above diversity of voltage-gated potassium channel detected in gene expression and electrical character in coronary artery smooth muscle of SHR than that of WKY might be an underling mechanism associated with the membrane potential depolarization in artery smooth muscle of SHR.
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Affiliation(s)
- Zhi Hu
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, No. 277 West Yanta Road, Xi'an, 710061, Shaanxi, China
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