1
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Leslie E, Lopez V, Anti NAO, Alvarez R, Kafeero I, Welsh DG, Romero M, Kaushal S, Johnson CM, Bosviel R, Blaženović I, Song R, Brito A, Frano MRL, Zhang L, Newman JW, Fiehn O, Wilson SM. Gestational long-term hypoxia induces metabolomic reprogramming and phenotypic transformations in fetal sheep pulmonary arteries. Am J Physiol Lung Cell Mol Physiol 2021; 320:L770-L784. [PMID: 33624555 DOI: 10.1152/ajplung.00469.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Gestational long-term hypoxia increases the risk of myriad diseases in infants including persistent pulmonary hypertension. Similar to humans, fetal lamb lung development is susceptible to long-term intrauterine hypoxia, with structural and functional changes associated with the development of pulmonary hypertension including pulmonary arterial medial wall thickening and dysregulation of arterial reactivity, which culminates in decreased right ventricular output. To further explore the mechanisms associated with hypoxia-induced aberrations in the fetal sheep lung, we examined the premise that metabolomic changes and functional phenotypic transformations occur due to intrauterine, long-term hypoxia. To address this, we performed electron microscopy, Western immunoblotting, calcium imaging, and metabolomic analyses on pulmonary arteries isolated from near-term fetal lambs that had been exposed to low- or high-altitude (3,801 m) hypoxia for the latter 110+ days of gestation. Our results demonstrate that the sarcoplasmic reticulum was swollen with high luminal width and distances to the plasma membrane in the hypoxic group. Hypoxic animals were presented with higher endoplasmic reticulum stress and suppressed calcium storage. Metabolically, hypoxia was associated with lower levels of multiple omega-3 polyunsaturated fatty acids and derived lipid mediators (e.g., eicosapentaenoic acid, docosahexaenoic acid, α-linolenic acid, 5-hydroxyeicosapentaenoic acid (5-HEPE), 12-HEPE, 15-HEPE, prostaglandin E3, and 19(20)-epoxy docosapentaenoic acid) and higher levels of some omega-6 metabolites (P < 0.02) including 15-keto prostaglandin E2 and linoleoylglycerol. Collectively, the results reveal broad evidence for long-term hypoxia-induced metabolic reprogramming and phenotypic transformations in the pulmonary arteries of fetal sheep, conditions that likely contribute to the development of persistent pulmonary hypertension.
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Affiliation(s)
- Eric Leslie
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico
| | - Vanessa Lopez
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Nana A O Anti
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Rafael Alvarez
- Center for Health Disparities and Molecular Mechanisms, Loma Linda University School of Medicine, Loma Linda, California
| | - Isaac Kafeero
- Center for Health Disparities and Molecular Mechanisms, Loma Linda University School of Medicine, Loma Linda, California
| | - Donald G Welsh
- Robarts Research Institute, Western University, London, Ontario, Canada
| | - Monica Romero
- Advanced Imaging and Microscopy Core, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Shawn Kaushal
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Catherine M Johnson
- Department of Food Science and Nutrition, California Polytechnic State University, San Luis Obispo, California
| | - Remy Bosviel
- NIH West Coast Metabolomics Center, Genome Center, University of California, Davis, California
| | - Ivana Blaženović
- NIH West Coast Metabolomics Center, Genome Center, University of California, Davis, California
| | - Rui Song
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Alex Brito
- Laboratory of Pharmacokinetics and Metabolomic Analysis, Institute of Translational Medicine and Biotechnology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia.,World-Class Research Center "Digital biodesign and personalized healthcare," I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Michael R La Frano
- Department of Food Science and Nutrition, California Polytechnic State University, San Luis Obispo, California.,Center for Health Research, California Polytechnic State University, San Luis Obispo, California.,Cal Poly Metabolomics Service Center, California Polytechnic State University, San Luis Obispo, California
| | - Lubo Zhang
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - John W Newman
- NIH West Coast Metabolomics Center, Genome Center, University of California, Davis, California.,Department of Nutrition, University of California, Davis, California.,USDA-ARS Western Human Nutrition Research Center, Davis, California
| | - Oliver Fiehn
- NIH West Coast Metabolomics Center, Genome Center, University of California, Davis, California.,West Coast Metabolomics Center, University of California, Davis, California
| | - Sean M Wilson
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California.,Advanced Imaging and Microscopy Core, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
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2
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Bisen S, Simakova MN, Dopico AM, Bukiya AN. Large conductance voltage- and calcium-gated potassium channels (BK) in cerebral artery myocytes of perinatal fetal primates share several major characteristics with the adult phenotype. PLoS One 2018; 13:e0203199. [PMID: 30212531 PMCID: PMC6136719 DOI: 10.1371/journal.pone.0203199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 06/19/2018] [Indexed: 12/30/2022] Open
Abstract
Large conductance voltage- and calcium-gated channels (BK) control fundamental processes, including smooth muscle contractility and artery diameter. We used a baboon (Papio spp) model of pregnancy that is similar to that of humans to characterize BK channels in the middle cerebral artery and its branches in near-term (165 dGa) primate fetuses and corresponding pregnant mothers. In cell-attached patches (K+pipette = 135 mM) on freshly isolated fetal cerebral artery myocytes, BK currents were identified by large conductance, and voltage- and paxilline-sensitive effects. Their calcium sensitivity was confirmed by a lower Vhalf (transmembrane voltage needed to reach half-maximal current) in inside-out patches at 30 versus 3 μM [Ca2+]free. Immunostaining against the BK channel-forming alpha subunit revealed qualitatively similar levels of BK alpha protein-corresponding fluorescence in fetal and maternal myocytes. Fetal and maternal BK currents recorded at 3 μM [Ca2+]free from excised membrane patches had similar unitary current amplitude, and Vhalf. However, subtle differences between fetal and maternal BK channel phenotypes were detected in macroscopic current activation kinetics. To assess BK function at the organ level, fetal and maternal artery branches were pressurized in vitro at 30 mmHg and probed with the selective BK channel blocker paxilline (1 μM). The degree of paxilline-induced constriction was similar in fetal and maternal arteries, yet the constriction of maternal arteries was achieved sooner. In conclusion, we present a first identification and characterization of fetal cerebral artery BK channels in myocytes from primates. Although differences in BK channels between fetal and maternal arteries exist, the similarities reported herein advance the idea that vascular myocyte BK channels are functional near-term, and thus may serve as pharmacological targets during the perinatal-neonatal period.
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Affiliation(s)
- Shivantika Bisen
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Maria N. Simakova
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Alex M. Dopico
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Anna N. Bukiya
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
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3
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Barnes EA, Lee L, Barnes SL, Brenner R, Alvira CM, Cornfield DN. β1-Subunit of the calcium-sensitive potassium channel modulates the pulmonary vascular smooth muscle cell response to hypoxia. Am J Physiol Lung Cell Mol Physiol 2018; 315:L265-L275. [PMID: 29644895 PMCID: PMC6139656 DOI: 10.1152/ajplung.00060.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 11/22/2022] Open
Abstract
Accessory subunits associated with the calcium-sensitive potassium channel (BKCa), a major determinant of vascular tone, confer functional and anatomical diversity. The β1 subunit increases Ca2+ and voltagesensitivity of the BKCa channel and is expressed exclusively in smooth muscle cells. Evidence supporting the physiological significance of the β1 subunit includes the observations that murine models with deletion of the β1 subunit are hypertensive and that humans with a gain-of-function β1 mutation are at a decreased risk of diastolic hypertension. However, whether the β1 subunit of the BKCa channel contributes to the low tone that characterizes the normal pulmonary circulation or modulates the pulmonary vascular response to hypoxia remains unknown. To determine the role of the BKCa channel β1 subunit in the regulation of pulmonary vascular tone and the response to acute and chronic hypoxia, mice with deletion of the Kcnmb1 gene that encodes for the β1 subunit ( Kcnmb1-/-) were placed in chronic hypoxia (10% O2) for 21-24 days. In normoxia, right ventricular systolic pressure (RVSP) did not differ between Kcnmb1+/+ (controls) and Kcnmb1-/- mice. After exposure to either acute or chronic hypoxia, RVSP was higher in Kcnmb1-/- mice compared with Kcnmb1+/+ mice, without increased vascular remodeling. β1 subunit expression was predominantly confined to pulmonary artery smooth muscle cells (PASMCs) from vessels ≤ 150 µm. Peripheral PASMCs contracted collagen gels irrespective of β1 expression. Focal adhesion expression and Rho kinase activity were greater in Kcnmb1-/- compared with Kcnmb1+/+ PASMCs. Compromised PASMC β1 function may contribute to the heightened microvascular vasoconstriction that characterizes pulmonary hypertension.
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MESH Headings
- Acute Disease
- Animals
- Chronic Disease
- Focal Adhesions/genetics
- Focal Adhesions/metabolism
- Focal Adhesions/pathology
- Gene Deletion
- Hypertension, Pulmonary/genetics
- Hypertension, Pulmonary/metabolism
- Hypertension, Pulmonary/pathology
- Hypoxia/genetics
- Hypoxia/metabolism
- Hypoxia/pathology
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/genetics
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/metabolism
- Lung/blood supply
- Lung/metabolism
- Lung/pathology
- Mice
- Mice, Knockout
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Pulmonary Artery/metabolism
- Pulmonary Artery/pathology
- Vasoconstriction
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Affiliation(s)
- Elizabeth A Barnes
- Division of Pulmonary Medicine, Department of Pediatrics, Stanford University School of Medicine , Stanford, California
| | - Lori Lee
- Division of Pulmonary Medicine, Department of Pediatrics, Stanford University School of Medicine , Stanford, California
| | - Shayna L Barnes
- Division of Pulmonary Medicine, Department of Pediatrics, Stanford University School of Medicine , Stanford, California
| | - Robert Brenner
- Department of Cellular and Integrative Physiology, School of Medicine, University of Texas Health Sciences Center , San Antonio, Texas
| | - Cristina M Alvira
- Division of Pulmonary Medicine, Department of Pediatrics, Stanford University School of Medicine , Stanford, California
- Division of Critical Care Medicine, Department of Pediatrics, Stanford University School of Medicine , Stanford, California
| | - David N Cornfield
- Division of Pulmonary Medicine, Department of Pediatrics, Stanford University School of Medicine , Stanford, California
- Division of Critical Care Medicine, Department of Pediatrics, Stanford University School of Medicine , Stanford, California
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4
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Papamatheakis DG, Chundu M, Blood AB, Wilson SM. Prenatal programming of pulmonary hypertension induced by chronic hypoxia or ductal ligation in sheep. Pulm Circ 2014; 3:757-80. [PMID: 25006393 DOI: 10.1086/674767] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 07/28/2013] [Indexed: 11/03/2022] Open
Abstract
Pulmonary hypertension of the newborn is caused by a spectrum of functional and structural abnormalities of the cardiopulmonary circuit. The existence of multiple etiologies and an incomplete understanding of the mechanisms of disease progression have hindered the development of effective therapies. Animal models offer a means of gaining a better understanding of the fundamental basis of the disease. To that effect, a number of experimental animal models are being used to generate pulmonary hypertension in the fetus and newborn. In this review, we compare the mechanisms associated with pulmonary hypertension caused by two such models: in utero ligation of the ductus arteriosus and chronic perinatal hypoxia in sheep fetuses and newborns. In this manner, we make direct comparisons between ductal ligation and chronic hypoxia with respect to the associated mechanisms of disease, since multiple studies have been performed with both models in a single species. We present evidence that the mechanisms associated with pulmonary hypertension are dependent on the type of stress to which the fetus is subjected. Such an analysis allows for a more thorough evaluation of the disease etiology, which can help focus clinical treatments. The final part of the review provides a clinical appraisal of current treatment strategies and lays the foundation for developing individualized therapies that depend on the causative factors.
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Affiliation(s)
- Demosthenes G Papamatheakis
- Division of Pulmonary and Critical Care, University of California San Diego Health System, San Diego, California, USA
| | - Madalitso Chundu
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California, USA
| | - Arlin B Blood
- Department of Pediatrics Division of Neonatology, and Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California, USA
| | - Sean M Wilson
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California, USA
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5
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Papamatheakis DG, Blood AB, Kim JH, Wilson SM. Antenatal hypoxia and pulmonary vascular function and remodeling. Curr Vasc Pharmacol 2014; 11:616-40. [PMID: 24063380 DOI: 10.2174/1570161111311050006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 06/25/2012] [Accepted: 07/12/2012] [Indexed: 01/02/2023]
Abstract
This review provides evidence that antenatal hypoxia, which represents a significant and worldwide problem, causes prenatal programming of the lung. A general overview of lung development is provided along with some background regarding transcriptional and signaling systems of the lung. The review illustrates that antenatal hypoxic stress can induce a continuum of responses depending on the species examined. Fetuses and newborns of certain species and specific human populations are well acclimated to antenatal hypoxia. However, antenatal hypoxia causes pulmonary vascular disease in fetuses and newborns of most mammalian species and humans. Disease can range from mild pulmonary hypertension, to severe vascular remodeling and dangerous elevations in pressure. The timing, length, and magnitude of the intrauterine hypoxic stress are important to disease development, however there is also a genetic-environmental relationship that is not yet completely understood. Determining the origins of pulmonary vascular remodeling and pulmonary hypertension and their associated effects is a challenging task, but is necessary in order to develop targeted therapies for pulmonary hypertension in the newborn due to antenatal hypoxia that can both treat the symptoms and curtail or reverse disease progression.
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Affiliation(s)
- Demosthenes G Papamatheakis
- Center for Perinatal Biology, Loma Linda University School of Medicine, 11234 Anderson Street, Loma Linda, 92350 CA, USA.
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6
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Abstract
Hypoxic pulmonary hypertension of the newborn is characterized by elevated pulmonary vascular resistance and pressure due to vascular remodeling and increased vessel tension secondary to chronic hypoxia during the fetal and newborn period. In comparison to the adult, the pulmonary vasculature of the fetus and the newborn undergoes tremendous developmental changes that increase susceptibility to a hypoxic insult. Substantial evidence indicates that chronic hypoxia alters the production and responsiveness of various vasoactive agents such as endothelium-derived nitric oxide, endothelin-1, prostanoids, platelet-activating factor, and reactive oxygen species, resulting in sustained vasoconstriction and vascular remodeling. These changes occur in most cell types within the vascular wall, particularly endothelial and smooth muscle cells. At the cellular level, suppressed nitric oxide-cGMP signaling and augmented RhoA-Rho kinase signaling appear to be critical to the development of hypoxic pulmonary hypertension of the newborn.
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Affiliation(s)
- Yuansheng Gao
- Department of Physiology and Pathophysiology, Peking University, Health Science Center, Beijing, China
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7
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Hadley SR, Blood Q, Rubalcava M, Waskel E, Lumbard B, Le P, Longo LD, Buchholz JN, Wilson SM. Maternal high-altitude hypoxia and suppression of ryanodine receptor-mediated Ca2+ sparks in fetal sheep pulmonary arterial myocytes. Am J Physiol Lung Cell Mol Physiol 2012; 303:L799-813. [PMID: 22962012 DOI: 10.1152/ajplung.00009.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Ca(2+) sparks are fundamental Ca(2+) signaling events arising from ryanodine receptor (RyR) activation, events that relate to contractile and dilatory events in the pulmonary vasculature. Recent studies demonstrate that long-term hypoxia (LTH) can affect pulmonary arterial reactivity in fetal, newborn, and adult animals. Because RyRs are important to pulmonary vascular reactivity and reactivity changes with ontogeny and LTH we tested the hypothesis that RyR-generated Ca(2+) signals are more active before birth and that LTH suppresses these responses. We examined these hypotheses by performing confocal imaging of myocytes in living arteries and by performing wire myography studies. Pulmonary arteries (PA) were isolated from fetal, newborn, or adult sheep that lived at low altitude or from those that were acclimatized to 3,801 m for > 100 days. Confocal imaging demonstrated preservation of the distance between the sarcoplasmic reticulum, nucleus, and plasma membrane in PA myocytes. Maturation increased global Ca(2+) waves and Ca(2+) spark activity, with sparks becoming larger, wider, and slower. LTH preferentially depressed Ca(2+) spark activity in immature pulmonary arterial myocytes, and these sparks were smaller, wider, and slower. LTH also suppressed caffeine-elicited contraction in fetal PA but augmented contraction in the newborn and adult. The influence of both ontogeny and LTH on RyR-dependent cell excitability shed new light on the therapeutic potential of these channels for the treatment of pulmonary vascular disease in newborns as well as adults.
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Affiliation(s)
- Scott R Hadley
- Center for Perinatal Biology, Loma Linda University, California 92350, USA
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8
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Abstract
It has been known for more than 60 years, and suspected for over 100, that alveolar hypoxia causes pulmonary vasoconstriction by means of mechanisms local to the lung. For the last 20 years, it has been clear that the essential sensor, transduction, and effector mechanisms responsible for hypoxic pulmonary vasoconstriction (HPV) reside in the pulmonary arterial smooth muscle cell. The main focus of this review is the cellular and molecular work performed to clarify these intrinsic mechanisms and to determine how they are facilitated and inhibited by the extrinsic influences of other cells. Because the interaction of intrinsic and extrinsic mechanisms is likely to shape expression of HPV in vivo, we relate results obtained in cells to HPV in more intact preparations, such as intact and isolated lungs and isolated pulmonary vessels. Finally, we evaluate evidence regarding the contribution of HPV to the physiological and pathophysiological processes involved in the transition from fetal to neonatal life, pulmonary gas exchange, high-altitude pulmonary edema, and pulmonary hypertension. Although understanding of HPV has advanced significantly, major areas of ignorance and uncertainty await resolution.
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Affiliation(s)
- J. T. Sylvester
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Larissa A. Shimoda
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Philip I. Aaronson
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Jeremy P. T. Ward
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
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9
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Abstract
During the development of the pulmonary vasculature in the fetus, many structural and functional changes occur to prepare the lung for the transition to air breathing. The development of the pulmonary circulation is genetically controlled by an array of mitogenic factors in a temporo-spatial order. With advancing gestation, pulmonary vessels acquire increased vasoreactivity. The fetal pulmonary vasculature is exposed to a low oxygen tension environment that promotes high intrinsic myogenic tone and high vasocontractility. At birth, a dramatic reduction in pulmonary arterial pressure and resistance occurs with an increase in oxygen tension and blood flow. The striking hemodynamic differences in the pulmonary circulation of the fetus and newborn are regulated by various factors and vasoactive agents. Among them, nitric oxide, endothelin-1, and prostaglandin I2 are mainly derived from endothelial cells and exert their effects via cGMP, cAMP, and Rho kinase signaling pathways. Alterations in these signaling pathways may lead to vascular remodeling, high vasocontractility, and persistent pulmonary hypertension of the newborn.
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Affiliation(s)
- Yuansheng Gao
- Department of Physiology and Pathophysiology, Peking University, Health Science Center, Beijing, China; and Department of Pediatrics, University of Illinois, College of Medicine at Chicago, Chicago, Illinois
| | - J. Usha Raj
- Department of Physiology and Pathophysiology, Peking University, Health Science Center, Beijing, China; and Department of Pediatrics, University of Illinois, College of Medicine at Chicago, Chicago, Illinois
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10
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Cornfield DN. Developmental regulation of oxygen sensing and ion channels in the pulmonary vasculature. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 661:201-20. [PMID: 20204732 DOI: 10.1007/978-1-60761-500-2_13] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The increase in oxygen tension occurring at birth causes sustained and progressive pulmonary vasodilation. The oxygen-induced perinatal pulmonary vasodilation depends on the production of nitric oxide (NO) from the pulmonary endothelium and activation of various K(+) channels in pulmonary artery smooth muscle cells. This chapter reviews a) the oxygen-sensing mechanism that stimulates endothelial NO production; b) how K(+) channels sense changes in oxygen tension; c) whether hypoxia-inducible factor-1alpha (HIF-1alpha), a well defined hypoxia-sensitive transcription factor in adult, contributes to the regulation of NO production and K(+) channel activation; and d) whether and how dysfunctional K(+) channels contribute to the development of pulmonary hypertension in the newborns.
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Affiliation(s)
- David N Cornfield
- Divisions of Pediatric Pulmonary, Allergy, and Critical Care Medicine, Stanford University Medical School Medicine, 770 Welch Road, Suite 350, Stanford, CA, 94305, USA.
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11
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Shen B, Ye CL, Ye KH, Zhuang L, Jiang JH. Doxorubicin-induced vasomotion and [Ca(2+)](i) elevation in vascular smooth muscle cells from C57BL/6 mice. Acta Pharmacol Sin 2009; 30:1488-95. [PMID: 19820720 PMCID: PMC4003006 DOI: 10.1038/aps.2009.145] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2009] [Accepted: 08/31/2009] [Indexed: 11/08/2022] Open
Abstract
AIM To explore the action of doxorubicin on vascular smooth muscle cells. METHODS Isometric tension of denuded or intact thoracic aortic vessels was recorded and [Ca(2+)](i) in isolated aortic smooth muscle cells was measured by using Fluo-3. RESULTS Doxorubicin induced phasic and tonic contractions in denuded vessels and increased levels of [Ca(2+)](i) in single muscle cells. Treatment with 10 micromol/L ryanodine had no effect on basal tension, but it did abolish doxorubicin-induced phasic contraction. Treatment with 10 mmol/L caffeine induced a transient phasic contraction only, and the effect was not significantly altered by ryanodine, the omission of extracellular Ca(2+) or both. Phenylephrine induced rhythmic contraction (RC) in intact vessels. Treatment with 100 micromol/L doxorubicin enhanced RC amplitude, but 1 mmol/L doxorubicin abolished RC, with an increase in maximal tension. Caffeine at 100 micromol/L increased the frequency of the RC only. In the presence of 100 micromol/L caffeine, however, 100 micromol/L doxorubicin abolished the RC and decreased its maximal tension. Treatment with 10 micromol/L ryanodine abolished the RC, with an increase in the maximal tension. In Ca(2+)-free solution, doxorubicin induced a transient [Ca(2+)](i) increase that could be abolished by ryanodine pretreatment in single muscle cells. The doxorubicin-induced increase in [Ca(2+)](i) was suppressed by nifedipine and potentiated by ryanodine and charybdotoxin. CONCLUSION Doxorubicin not only releases Ca(2+) from the sarcoplasmic reticulum but also promotes the entry of extracellular Ca(2+) into vascular smooth muscle cells.
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MESH Headings
- Aniline Compounds
- Animals
- Antibiotics, Antineoplastic/pharmacology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Calcium/metabolism
- Doxorubicin/pharmacology
- Fluorescent Dyes
- Isometric Contraction/drug effects
- Male
- Mice
- Mice, Inbred C57BL
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Sarcoplasmic Reticulum/drug effects
- Sarcoplasmic Reticulum/metabolism
- Xanthenes
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Affiliation(s)
- Bing Shen
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
- Department of Pharmacology, Anhui Medical University, Hefei 230022, China
| | - Chun-ling Ye
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
| | - Kai-he Ye
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
| | - Lan Zhuang
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
| | - Jia-hua Jiang
- Department of Pharmacology, Pharmaceutical College, Ji-nan University, Guangzhou 510632, China
- Division of Cardiovascular Research, The Hospital for Sick Children, Toronto, Canada
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12
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Goyal R, Creel KD, Chavis E, Smith GD, Longo LD, Wilson SM. Maturation of intracellular calcium homeostasis in sheep pulmonary arterial smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 2008; 295:L905-14. [PMID: 18776056 DOI: 10.1152/ajplung.00053.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytosolic Ca(2+) signaling dynamics are important to pulmonary arterial reactivity, and alterations are implicated in pulmonary vascular disorders. Yet, adaptations in cellular Ca(2+) homeostasis and receptor-mediated Ca(2+) signaling with maturation from fetal to adult life in pulmonary arterial smooth muscle cells (PASMCs) are not known. The present study tested the hypothesis that cytosolic Ca(2+) homeostasis and receptor-generated Ca(2+) signaling adapt with maturation in sheep PASMCs. Digitalized fluorescence microscopy was performed using isolated PASMCs from fetal and adult sheep that were loaded with the Ca(2+) indicator fura 2. The results show that basal cytosolic and sarcoplasmic reticulum Ca(2+) levels are attained before birth. Similarly, Ca(2+) efflux pathways from the cytosol and basal as well as capacitative Ca(2+) entry (CCE) are also developed before birth. However, receptor-mediated Ca(2+) signaling adapts with maturation. Prominently, serotonin stimulation elicited Ca(2+) elevations in very few fetal compared with adult PASMCs; in contrast, phenylephrine elevated Ca(2+) in a similar percentage of fetal and adult PASMCs. Serotonin and phenylephrine elicited Ca(2+) increases of a similar magnitude in reactive cells of fetus and adult, supporting the assertion that inositol trisphosphate signaling is intact. Caffeine and ATP elevated Ca(2+) in equivalent numbers of fetal and adult PASMCs. However, the caffeine-induced cytosolic Ca(2+) increase was significantly greater in fetal PASMCs, whereas the ATP-elicited increase was greater in adult cells. Overall, the results of this study demonstrate selective adaptations in receptor-mediated Ca(2+) signaling, but not in cellular Ca(2+) homeostasis.
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Affiliation(s)
- Ravi Goyal
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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13
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Tirosh R, Resnik ER, Herron J, Sukovich DJ, Hong Z, Weir EK, Cornfield DN. Acute normoxia increases fetal pulmonary artery endothelial cell cytosolic Ca2+ via Ca2+-induced Ca2+ release. Pediatr Res 2006; 60:258-63. [PMID: 16857761 DOI: 10.1203/01.pdr.0000233077.29866.f0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
To test the hypothesis that an acute increase in O(2) tension increases cytosolic calcium ([Ca(2+)](i)) in fetal pulmonary artery endothelial cells (PAECs) via entry of extracellular calcium and subsequent calcium-induced calcium release (CICR) and nitric oxide release, low-passage PAECs (<10 passages) were isolated from the intralobar pulmonary artery (PA) of fetal sheep and maintained under hypoxic conditions (Po(2), 25 Torr). Using the calcium-sensitive dye fura-2, we demonstrated that acute normoxia (Po(2) = 120 Torr) increased PAECs [Ca(2+)](i) by increasing the rate of entry of extracellular calcium. In the presence of either ryanodine or 2-aminoethoxy-diphenylborate (2APB), normoxia did not lead to a sustained increase in PAECs [Ca(2+)](i) Whole-cell patch clamp studies demonstrated that acute normoxia causes PAEC membrane depolarization. When loaded with the nitric oxide (NO)-sensitive dye, DAF - FM, acute normoxia increased PAEC fluorescence. In PAECs derived from fetal lambs with pulmonary hypertension, an acute increase in O(2) tension had no effect on either [Ca(2+)](i) or NO production. Hypoxia increases loading of acetylcholine-sensitive calcium stores, as hypoxia potentiated the response to acetylcholine We conclude that acute normoxia increases [Ca(2+)](i) and NO production in normotensive but not hypertensive fetal PAECs via extracellular calcium entry and calcium release from calcium-sensitive intracellular stores.
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Affiliation(s)
- Raz Tirosh
- Department of Pediatrics, Division of Pediatric Pulmonary and Critical Care Medicine, University of Minnesota, Minneapolis, MN 55455, USA
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Hinton M, Mellow L, Halayko AJ, Gutsol A, Dakshinamurti S. Hypoxia induces hypersensitivity and hyperreactivity to thromboxane receptor agonist in neonatal pulmonary arterial myocytes. Am J Physiol Lung Cell Mol Physiol 2005; 290:L375-84. [PMID: 16214814 DOI: 10.1152/ajplung.00307.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
PPHN, caused by perinatal hypoxia or inflammation, is characterized by an increased thromboxane-prostacyclin ratio and pulmonary vasoconstriction. We examined effects of hypoxia on myocyte thromboxane responsiveness. Myocytes from 3rd-6th generation pulmonary arteries of newborn piglets were grown to confluence and synchronized in contractile phenotype by serum deprivation. On the final 3 days of culture, myocytes were exposed to 10% O2 for 3 days; control myocytes from normoxic piglets were cultured in 21% O2. PPHN was induced in newborn piglets by 3-day hypoxic exposure (Fi(O2) 0.10); pulmonary arterial myocytes from these animals were maintained in normoxia. Ca2+ mobilization to thromboxane mimetic U-46619 and ATP was quantified using fura-2 AM. Three-day hypoxic exposure in vitro results in increased basal [Ca2+]i, faster and heightened peak Ca2+ response, and decreased U-46619 EC50. These functional changes persist in myocytes exposed to hypoxia in vivo but cultured in 21% O2. Blockade of Ca2+ entry and store refilling do not alter peak U-46619 Ca2+ responses in hypoxic or normoxic myocytes. Blockade of ryanodine-sensitive or IP3-gated intracellular Ca2+ channels inhibits hypoxic augmentation of peak U-46619 response. Ca2+ response to ryanodine alone is undetectable; ATP-induced Ca2+ mobilization is unaltered by hypoxia, suggesting no independent increase in ryanodine-sensitive or IP3-linked intracellular Ca2+ pool mobilization. We conclude hypoxia has a priming effect on neonatal pulmonary arterial myocytes, resulting in increased resting Ca2+, thromboxane hypersensitivity, and hyperreactivity. We postulate that hypoxia increases agonist-induced TP-R-linked IP3 pathway activation. Myocyte thromboxane hyperresponsiveness persists in culture after removal from the initiating hypoxic stimulus, suggesting altered gene expression.
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Affiliation(s)
- M Hinton
- Department of Physiology, University of Manitoba, and Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Canada R3A 1R9
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15
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Mauban JRH, Remillard CV, Yuan JXJ. Hypoxic pulmonary vasoconstriction: role of ion channels. J Appl Physiol (1985) 2005; 98:415-20. [PMID: 15591311 DOI: 10.1152/japplphysiol.00732.2004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acute hypoxia induces pulmonary vasoconstriction and chronic hypoxia causes structural changes of the pulmonary vasculature including arterial medial hypertrophy. Electro- and pharmacomechanical mechanisms are involved in regulating pulmonary vasomotor tone, whereas intracellular Ca(2+) serves as an important signal in regulating contraction and proliferation of pulmonary artery smooth muscle cells. Herein, we provide a basic overview of the cellular mechanisms involved in the development of hypoxic pulmonary vasoconstriction. Our discussion focuses on the roles of ion channels permeable to K(+) and Ca(2+), membrane potential, and cytoplasmic Ca(2+) in the development of acute hypoxic pulmonary vasoconstriction and chronic hypoxia-mediated pulmonary vascular remodeling.
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Affiliation(s)
- Joseph R H Mauban
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California-San Diego, 9500 Gilman Dr., MC 0725, La Jolla, CA 92093-0725, USA
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16
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Yang XR, Lin MJ, Yip KP, Jeyakumar LH, Fleischer S, Leung GPH, Sham JSK. Multiple ryanodine receptor subtypes and heterogeneous ryanodine receptor-gated Ca2+ stores in pulmonary arterial smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 2005; 289:L338-48. [PMID: 15863441 DOI: 10.1152/ajplung.00328.2004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ryanodine receptors (RyRs) of pulmonary arterial smooth muscle cells (PASMCs) play important roles in major physiological processes such as hypoxic pulmonary vasoconstriction and perinatal pulmonary vasodilatation. Recent studies show that three subtypes of RyRs are coexpressed and RyR-gated Ca2+ stores are distributed heterogeneously in systemic vascular myocytes. However, the molecular identity and subcellular distribution of RyRs have not been examined in PASMCs. In this study we detected mRNA and proteins of all three subtypes in rat intralobar PASMCs using RT-PCR and Western blot. Quantitative real-time RT-PCR showed that RyR2 mRNA was most abundant, approximately 15-20 times more than the other two subtypes. Confocal fluorescence microscopy revealed that RyRs labeled with BODIPY TR-X ryanodine were localized in the peripheral and perinuclear regions and were colocalized with sarcoplasmic reticulum labeled with Fluo-5N. Immunostaining showed that the subsarcolemmal regions exhibited clear signals of RyR1 and RyR2, whereas the perinuclear compartments contained mainly RyR1 and RyR3. Ca2+ sparks were recorded in both regions, and their activities were enhanced by a subthreshold concentration of caffeine or by endothelin-1, indicating functional RyR-gated Ca2+ stores. Moreover, 18% of the perinuclear sparks were prolonged [full duration/half-maximum (FDHM) = 193.3 +/- 22.6 ms] with noninactivating kinetics, in sharp contrast to the typical fast inactivating Ca2+ sparks (FDHM = 44.6 +/- 3.2 ms) recorded in the same PASMCs. In conclusion, multiple RyR subtypes are expressed differentially in peripheral and perinuclear RyR-gated Ca2+ stores; the molecular complexity and spatial heterogeneity of RyRs may facilitate specific Ca2+ regulation of cellular functions in PASMCs.
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Affiliation(s)
- Xiao-Ru Yang
- Div. of Pulmonary and Critical Care Medicine, Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Cir., Baltimore, MD 21224, USA
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17
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Olschewski A, Hong Z, Peterson DA, Nelson DP, Porter VA, Weir EK. Opposite effects of redox status on membrane potential, cytosolic calcium, and tone in pulmonary arteries and ductus arteriosus. Am J Physiol Lung Cell Mol Physiol 2004; 286:L15-22. [PMID: 12842809 DOI: 10.1152/ajplung.00372.2002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
At birth, associated with the rise in oxygen tension, the pulmonary arteries (PA) dilate and the ductus arteriosus (DA) constricts. Both PA and DA constrict with vasoconstrictors and dilate with vasodilators. They respond in a contrary manner only to changes in oxygen tension. We hypothesized that the effects of changes in oxygen are mediated by changes in redox status. Consequently, we tested whether a reducing agent, DTT, and an oxidizing agent, dithionitrobenzoic acid (DTNB), would have opposite effects on a major oxygen signaling pathway in the PA and DA smooth muscle cells (SMCs), the sequence of change in potassium current (IK), membrane potential (Em), cytosolic calcium, and vessel tone. Under normoxic conditions, DTT constricted adult and fetal resistance PA rings, whereas in DA rings DTT acted as a potent vasodilator. In normoxia, voltage-clamp measurements showed inhibition of IK by DTT in PASMCs and, in contrast, activation in DASMCs. Consequently, DTT depolarized fetal and adult PASMCs and hyperpolarized DASMCs. [Ca2+]i was increased by DTT in fetal and adult PASMCs and decreased in DASMCs. Under hypoxic conditions, DTNB constricted DA rings and caused vasodilatation in fetal PA rings. DTNB inhibited IK and depolarized the cell membrane in DASMCs. In contrast, activation of IK and hyperpolarization was seen in PASMCs. Thus the same redox signal can elicit opposite effects on IK, Em, cytosolic calcium, and vascular tone in resistance PA and the DA. These observations support the concept that redox changes could signal the opposite effects of oxygen in the PA and DA.
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Linden BC, Resnik ER, Hendrickson KJ, Herron JM, O'Connor TJ, Cornfield DN. Chronic intrauterine pulmonary hypertension compromises fetal pulmonary artery smooth muscle cell O2 sensing. Am J Physiol Lung Cell Mol Physiol 2003; 285:L1354-61. [PMID: 12882761 DOI: 10.1152/ajplung.00091.2003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To test the hypothesis that chronic intrauterine pulmonary hypertension (PHTN) compromises pulmonary artery (PA) smooth muscle cell (SMC) O2 sensing, fluorescence microscopy was used to study the effect of an acute increase in Po2 on the cytosolic Ca2+ concentration ([Ca2+]i) of chronically hypoxic subconfluent monolayers of PA SMC in primary culture. PA SMCs were derived from fetal lambs with PHTN due to intrauterine ligation of the ductus arteriosus. Acute normoxia decreased [Ca2+]i in control but not PHTN PA SMC. In control PA SMC, [Ca2+]i increased after Ca2+-sensitive (KCa) and voltage-sensitive (Kv) K+ channel blockade and decreased after diltiazem treatment. In PHTN PA SMC, KCa blockade had no effect, whereas Kv blockade and diltiazem increased [Ca2+]i. Inhibition of sarcoplasmic reticulum Ca2+ ATPase activity caused a greater increase in [Ca2+]i in controls compared with PHTN PA SMC. Conversely, ryanodine caused a greater increase of [Ca2+]i in PHTN compared with control PA SMC. KCa channel mRNA is decreased and Kv channel mRNA is unchanged in PHTN PA SMC compared with controls. We conclude that PHTN compromises PA SMC O2 sensing, alters intracellular Ca2+ homeostasis, and changes the predominant ion channel that determines basal [Ca2+]i from KCa to Kv.
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Affiliation(s)
- Bradley C Linden
- Department of Surgery, University of Minnesota Medical School, 420 Delaware St. SE, Minneapolis, MN 55455, USA.
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Zhang WM, Yip KP, Lin MJ, Shimoda LA, Li WH, Sham JSK. ET-1 activates Ca2+ sparks in PASMC: local Ca2+ signaling between inositol trisphosphate and ryanodine receptors. Am J Physiol Lung Cell Mol Physiol 2003; 285:L680-90. [PMID: 12740215 DOI: 10.1152/ajplung.00067.2003] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ca+ sparks originating from ryanodine receptors (RyRs) are known to cause membrane hyperpolarization and vasorelaxation in systemic arterial myocytes. By contrast, we have found that Ca2+ sparks of pulmonary arterial smooth muscle cells (PASMCs) are associated with membrane depolarization and activated by endothelin-1 (ET-1), a potent vasoconstrictor that mediates/modulates acute and chronic hypoxic pulmonary vasoconstriction. In this study, we characterized the effects of ET-1 on the physical properties of Ca2+ sparks and probed the signal transduction mechanism for spark activation in rat intralobar PASMCs. Application of ET-1 at 0.1-10 nM caused concentration-dependent increases in frequency, duration, and amplitude of Ca2+ sparks. The ET-1-induced increase in spark frequency was inhibited by BQ-123, an ETA-receptor antagonist; by U-73122, a PLC inhibitor; and by xestospongin C and 2-aminoethyl diphenylborate, antagonists of inositol trisphosphate (IP3) receptors (IP3Rs). However, it was unrelated to sarcoplasmic reticulum Ca2+ content, activation of L-type Ca2+ channels, PKC, or cADP ribose. Photorelease of caged-IP3 indicated that Ca2+ release from IP3R could cross-activate RyRs to generate Ca2+ sparks. Immunocytochemistry showed that the distributions of IP3Rs and RyRs were similar in PASMCs. Moreover, inhibition of Ca2+ sparks with ryanodine caused a significant rightward shift in the ET-1 concentration-tension relationship in pulmonary arteries. These results suggest that ET-1 activation of Ca2+ sparks is mediated via the ETA receptor-PLC-IP3 pathway and local Ca2+ cross-signaling between IP3Rs and RyRs; in addition, this novel signaling mechanism contributes significantly to the ET-1-induced vasoconstriction in pulmonary arteries.
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Affiliation(s)
- Wei-Min Zhang
- Div. of Pulmonary and Critical Care Medicine, Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
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Remillard CV, Zhang WM, Shimoda LA, Sham JSK. Physiological properties and functions of Ca(2+) sparks in rat intrapulmonary arterial smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 2002; 283:L433-44. [PMID: 12114206 DOI: 10.1152/ajplung.00468.2001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ca(+) spark has been implicated as a pivotal feedback mechanism for regulating membrane potential and vasomotor tone in systemic arterial smooth muscle cells (SASMCs), but little is known about its properties in pulmonary arterial smooth muscle cells (PASMCs). Using confocal microscopy, we identified spontaneous Ca(2+) sparks in rat intralobar PASMCs and characterized their spatiotemporal properties and physiological functions. Ca(2+) sparks of PASMCs had a lower frequency and smaller amplitude than cardiac sparks. They were abolished by inhibition of ryanodine receptors but not by inhibition of inositol trisphosphate receptors and L-type Ca(2+) channels. Enhanced Ca(2+) influx by BAY K8644, K(+), or high Ca(2+) caused a significant increase in spark frequency. Functionally, enhancing Ca(2+) sparks with caffeine (0.5 mM) caused membrane depolarization in PASMCs, in contrast to hyperpolarization in SASMCs. Norepinephrine and endothelin-1 both caused global elevations in cytosolic Ca(2+) concentration ([Ca(2+)]), but only endothelin-1 increased spark frequency. These results suggest that Ca(2+) sparks of PASMCs are similar to those of SASMCs, originate from ryanodine receptors, and are enhanced by Ca(2+) influx. However, they play a different modulatory role on membrane potential and are under agonist-specific regulation independent of global [Ca(2+)].
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Affiliation(s)
- Carmelle V Remillard
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland 21224, USA
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21
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Daniel EE. The smooth muscle cell membrane and peripheral sarcoplasmic reticulum: their interactions are organized and may be crucial. J Hypertens 2002; 20:367-70. [PMID: 11875298 DOI: 10.1097/00004872-200203000-00006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Morio Y, McMurtry IF. Ca(2+) release from ryanodine-sensitive store contributes to mechanism of hypoxic vasoconstriction in rat lungs. J Appl Physiol (1985) 2002; 92:527-34. [PMID: 11796660 DOI: 10.1152/jappl.2002.92.2.527] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Studies of thapsigargin, cyclopiazonic acid, and ryanodine in isolated pulmonary arteries and smooth muscle cells suggest that release of Ca(2+) from inositol 1,4,5-trisphosphate (IP(3))- and/or ryanodine-sensitive sarcoplasmic reticulum Ca(2+) stores is a component of the mechanism of acute hypoxic pulmonary vasoconstriction (HPV). However, the actions of these agents on HPV in perfused lungs have not been reported. Thus we tested effects of thapsigargin and cyclopiazonic acid, inhibitors of sarcoplasmic reticulum Ca(2+)-ATPase, and of ryanodine, an agent that either locks the ryanodine receptor open or blocks it, on HPV in salt solution-perfused rat lungs. After inhibition of cyclooxygenase and nitric oxide synthase, thapsigargin (10 nM) and cyclopiazonic acid (5 microM) augmented the vasoconstriction to 0% but not to 3% inspired O(2). Relatively high concentrations of ryanodine (100 and 300 microM) blunted HPV in nitric oxide synthase-inhibited lungs. The results indicate that release of Ca(2+) from the ryanodine-sensitive, but not the IP(3)-sensitive, store, contributes to the mechanism of HPV in perfused rat lungs and that Ca(2+)-ATPase-dependent Ca(2+) buffering moderates the response to severe hypoxia.
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Affiliation(s)
- Yoshiteru Morio
- Cardiovascular Pulmonary Research Laboratory, Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
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Porter VA, Rhodes MT, Reeve HL, Cornfield DN. Oxygen-induced fetal pulmonary vasodilation is mediated by intracellular calcium activation of K(Ca) channels. Am J Physiol Lung Cell Mol Physiol 2001; 281:L1379-85. [PMID: 11704533 DOI: 10.1152/ajplung.2001.281.6.l1379] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
O(2) sensing in fetal pulmonary artery smooth muscle is critically important in the successful transition to air breathing at birth. However, the mechanism by which the fetal pulmonary vasculature senses and responds to an acute increase in O(2) tension is not known. Isolated fetal pulmonary artery smooth muscle cells were kept in primary culture for 5-14 days in a hypoxic environment (20-30 mmHg). These cells showed a 25.1 +/- 1.7% decrease in intracellular calcium in response to an acute increase in O(2) tension. Low concentrations of caffeine (0.5 mM) and diltiazem also decreased intracellular calcium. The decrease in intracellular calcium concentration in response to increasing O(2) was inhibited by iberiotoxin and ryanodine. Freshly isolated fetal pulmonary artery smooth muscle cells exhibited "spontaneous transient outward currents," indicative of intracellular calcium spark activation of calcium-sensitive potassium channels. The frequency of spontaneous transient outward currents increased when O(2) tension was increased to normoxic levels. Increasing fetal pulmonary O(2) tension in acutely instrumented fetal sheep increased fetal pulmonary blood flow. Ryanodine attenuated O(2)-induced pulmonary vasodilation. This study demonstrates that fetal pulmonary vascular smooth muscle cells are capable of responding to an acute increase in O(2) tension and that this O(2) response is mediated by intracellular calcium activation of calcium-sensitive potassium channels.
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Affiliation(s)
- V A Porter
- Division of Pediatric Pulmonology and Critical Care Medicine, Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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