1
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Wang YX, Reyes-García J, Di Mise A, Zheng YM. Role of ryanodine receptor 2 and FK506-binding protein 12.6 dissociation in pulmonary hypertension. J Gen Physiol 2023; 155:213798. [PMID: 36625865 PMCID: PMC9836826 DOI: 10.1085/jgp.202213100] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 07/29/2022] [Accepted: 12/19/2022] [Indexed: 01/11/2023] Open
Abstract
Pulmonary hypertension (PH) is a devastating disease characterized by a progressive increase in pulmonary arterial pressure leading to right ventricular failure and death. A major cellular response in this disease is the contraction of smooth muscle cells (SMCs) of the pulmonary vasculature. Cell contraction is determined by the increase in intracellular Ca2+ concentration ([Ca2+]i), which is generated and regulated by various ion channels. Several studies by us and others have shown that ryanodine receptor 2 (RyR2), a Ca2+-releasing channel in the sarcoplasmic reticulum (SR), is an essential ion channel for the control of [Ca2+]i in pulmonary artery SMCs (PASMCs), thereby mediating the sustained vasoconstriction seen in PH. FK506-binding protein 12.6 (FKBP12.6) strongly associates with RyR2 to stabilize its functional activity. FKBP12.6 can be dissociated from RyR2 by a hypoxic stimulus to increase channel function and Ca2+ release, leading to pulmonary vasoconstriction and PH. More specifically, dissociation of the RyR2-FKBP12.6 complex is a consequence of increased mitochondrial ROS generation mediated by the Rieske iron-sulfur protein (RISP) at the mitochondrial complex III after hypoxia. Overall, RyR2/FKBP12.6 dissociation and the corresponding signaling pathway may be an important factor in the development of PH. Novel drugs and biologics targeting RyR2, FKBP12.6, and related molecules may become unique effective therapeutics for PH.
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Affiliation(s)
- Yong-Xiao Wang
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA,Correspondence to Yong-Xiao Wang:
| | - Jorge Reyes-García
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA,Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México,Ciudad de México, México
| | - Annarita Di Mise
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA,Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Yun-Min Zheng
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA,Yun-Min Zheng:
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2
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Moreno-Domínguez A, Colinas O, Smani T, Ureña J, López-Barneo J. Acute oxygen sensing by vascular smooth muscle cells. Front Physiol 2023; 14:1142354. [PMID: 36935756 PMCID: PMC10020353 DOI: 10.3389/fphys.2023.1142354] [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: 01/11/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
An adequate supply of oxygen (O2) is essential for most life forms on earth, making the delivery of appropriate levels of O2 to tissues a fundamental physiological challenge. When O2 levels in the alveoli and/or blood are low, compensatory adaptive reflexes are produced that increase the uptake of O2 and its distribution to tissues within a few seconds. This paper analyzes the most important acute vasomotor responses to lack of O2 (hypoxia): hypoxic pulmonary vasoconstriction (HPV) and hypoxic vasodilation (HVD). HPV affects distal pulmonary (resistance) arteries, with its homeostatic role being to divert blood to well ventilated alveoli to thereby optimize the ventilation/perfusion ratio. HVD is produced in most systemic arteries, in particular in the skeletal muscle, coronary, and cerebral circulations, to increase blood supply to poorly oxygenated tissues. Although vasomotor responses to hypoxia are modulated by endothelial factors and autonomic innervation, it is well established that arterial smooth muscle cells contain an acute O2 sensing system capable of detecting changes in O2 tension and to signal membrane ion channels, which in turn regulate cytosolic Ca2+ levels and myocyte contraction. Here, we summarize current knowledge on the nature of O2 sensing and signaling systems underlying acute vasomotor responses to hypoxia. We also discuss similarities and differences existing in O2 sensors and effectors in the various arterial territories.
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Affiliation(s)
- Alejandro Moreno-Domínguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Olaia Colinas
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Tarik Smani
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - Juan Ureña
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- *Correspondence: José López-Barneo,
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3
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Iturriaga R, Castillo-Galán S. The Beneficial Effect of the Blockade of Stim-Activated TRPC-ORAI Channels on Vascular Remodeling and Pulmonary Hypertension Induced by Intermittent Hypoxia Is Independent of Oxidative Stress. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1427:53-60. [PMID: 37322335 DOI: 10.1007/978-3-031-32371-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Obstructive sleep apnea (OSA), a sleep breathing disorder featured by chronic intermittent hypoxia (CIH), is associated with pulmonary hypertension (PH). Rats exposed to CIH develop systemic and lung oxidative stress, pulmonary vascular remodeling, and PH and overexpress Stim-activated TRPC-ORAI channels (STOC) in the lung. Previously, we demonstrated that 2-aminoethyl-diphenylborinate (2-APB)-treatment, a STOC-blocker, prevents PH and the overexpression of STOC induced by CIH. However, 2-APB did not prevent systemic and pulmonary oxidative stress. Accordingly, we hypothesize that the contribution of STOC in the development of PH induced by CIH is independent of oxidative stress. We measured the correlation between right ventricular systolic pressure (RVSP) and lung malondialdehyde (MDA) with the gene expression of STOC and morphological parameters in the lung from control, CIH-treated, and 2-APB-treated rats. We found correlations between RVSP and increased medial layer and STOC pulmonary levels. 2-APB-treated rats showed a correlation between RVSP and the medial layer thickness, α-actin-ir, and STOC, whereas RVSP did not correlate with MDA levels in CIH and 2-APB-treated rats. CIH rats showed correlations between lung MDA levels and the gene expression of TRPC1 and TRPC4. These results suggest that STOC channels play a key role in developing CIH-induced PH that is independent from lung oxidative stress.
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Affiliation(s)
- Rodrigo Iturriaga
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación en Fisiología y Medicina de Altura (FIMEDALT), Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Sebastián Castillo-Galán
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación en Fisiología y Medicina de Altura (FIMEDALT), Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile
- Laboratory of Nano-Regenerative Medicine, Centro de Investigación e Innovación Biomédica (CIIB), Faculty of Medicine, Universidad de los Andes, Santiago, Chile
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4
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Castillo-Galán S, Riquelme B, Iturriaga R. Crucial Role of Stromal Interaction Molecule-Activated TRPC-ORAI Channels in Vascular Remodeling and Pulmonary Hypertension Induced by Intermittent Hypoxia. Front Physiol 2022; 13:841828. [PMID: 35370769 PMCID: PMC8969100 DOI: 10.3389/fphys.2022.841828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Obstructive sleep apnea (OSA), a sleep breathing disorder featured by chronic intermittent hypoxia (CIH), is associate with pulmonary hypertension. Rats exposed to CIH develop lung vascular remodeling and pulmonary hypertension, which paralleled the upregulation of stromal interaction molecule (STIM)-activated TRPC-ORAI Ca2+ channels (STOC) in the lung, suggesting that STOC participate in the pulmonary vascular alterations. Accordingly, to evaluate the role played by STOC in pulmonary hypertension we studied whether the STOC blocker 2-aminoethoxydiphenyl borate (2-APB) may prevent the vascular remodeling and the pulmonary hypertension induced by CIH in a rat model of OSA. We assessed the effects of 2-APB on right ventricular systolic pressure (RVSP), pulmonary vascular remodeling, α-actin and proliferation marker Ki-67 levels in pulmonary arterial smooth muscle cells (PASMC), mRNA levels of STOC subunits, and systemic and pulmonary oxidative stress (TBARS) in male Sprague-Dawley (200 g) rats exposed to CIH (5% O2, 12 times/h for 8h) for 28 days. At 14 days of CIH, osmotic pumps containing 2-APB (10 mg/kg/day) or its vehicle were implanted and rats were kept for 2 more weeks in CIH. Exposure to CIH for 28 days raised RVSP > 35 mm Hg, increased the medial layer thickness and the levels of α-actin and Ki-67 in PASMC, and increased the gene expression of TRPC1, TRPC4, TRPC6 and ORAI1 subunits. Treatment with 2-APB prevented the raise in RVSP and the increment of the medial layer thickness, as well as the increased levels of α-actin and Ki-67 in PASMC, and the increased gene expression of STOC subunits. In addition, 2-APB did not reduced the lung and systemic oxidative stress, suggesting that the effects of 2-APB on vascular remodeling and pulmonary hypertension are independent on the reduction of the oxidative stress. Thus, our results supported that STIM-activated TRPC-ORAI Ca2+ channels contributes to the lung vascular remodeling and pulmonary hypertension induced by CIH.
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Affiliation(s)
- Sebastián Castillo-Galán
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Bárbara Riquelme
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
- *Correspondence: Rodrigo Iturriaga,
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5
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Castillo-Galán S, Parrau D, Hernández I, Quezada S, Díaz M, Ebensperger G, Herrera EA, Moraga FA, Iturriaga R, Llanos AJ, Reyes RV. The Action of 2-Aminoethyldiphenyl Borinate on the Pulmonary Arterial Hypertension and Remodeling of High-Altitude Hypoxemic Lambs. Front Physiol 2022; 12:765281. [PMID: 35082688 PMCID: PMC8784838 DOI: 10.3389/fphys.2021.765281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/07/2021] [Indexed: 01/17/2023] Open
Abstract
Calcium signaling is key for the contraction, differentiation, and proliferation of pulmonary arterial smooth muscle cells. Furthermore, calcium influx through store-operated channels (SOCs) is particularly important in the vasoconstrictor response to hypoxia. Previously, we found a decrease in pulmonary hypertension and remodeling in normoxic newborn lambs partially gestated under chronic hypoxia, when treated with 2-aminoethyldiphenyl borinate (2-APB), a non-specific SOC blocker. However, the effects of 2-APB are unknown in neonates completely gestated, born, and raised under environmental hypoxia. Accordingly, we studied the effects of 2-APB-treatment on the cardiopulmonary variables in lambs under chronic hypobaric hypoxia. Experiments were done in nine newborn lambs gestated, born, and raised in high altitude (3,600 m): five animals were treated with 2-APB [intravenous (i.v.) 10 mg kg–1] for 10 days, while other four animals received vehicle. During the treatment, cardiopulmonary variables were measured daily, and these were also evaluated during an acute episode of superimposed hypoxia, 1 day after the end of the treatment. Furthermore, pulmonary vascular remodeling was assessed by histological analysis 2 days after the end of the treatment. Basal cardiac output and mean systemic arterial pressure (SAP) and resistance from 2-APB- and vehicle-treated lambs did not differ along with the treatment. Mean pulmonary arterial pressure (mPAP) decreased after the first day of 2-APB treatment and remained lower than the vehicle-treated group until the third day, and during the fifth, sixth, and ninth day of treatment. The net mPAP increase in response to acute hypoxia did not change, but the pressure area under the curve (AUC) during hypoxia was slightly lower in 2-APB-treated lambs than in vehicle-treated lambs. Moreover, the 2-APB treatment decreased the pulmonary arterial wall thickness and the α-actin immunoreactivity and increased the luminal area with no changes in the vascular density. Our findings show that 2-APB treatment partially reduced the contractile hypoxic response and reverted the pulmonary vascular remodeling, but this is not enough to normalize the pulmonary hemodynamics in chronically hypoxic newborn lambs.
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Affiliation(s)
- Sebastián Castillo-Galán
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Daniela Parrau
- Unidad de Fisiología y Fisiopatología Perinatal, Programa de Fisiopatología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Ismael Hernández
- Unidad de Fisiología y Fisiopatología Perinatal, Programa de Fisiopatología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Sebastián Quezada
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, Australia
| | - Marcela Díaz
- Departamento de Promoción de la Salud de la Mujer y el Recién Nacido, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Germán Ebensperger
- Unidad de Fisiología y Fisiopatología Perinatal, Programa de Fisiopatología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,International Center for Andean Studies, Universidad de Chile, Santiago, Chile
| | - Emilio A Herrera
- Unidad de Fisiología y Fisiopatología Perinatal, Programa de Fisiopatología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,International Center for Andean Studies, Universidad de Chile, Santiago, Chile
| | - Fernando A Moraga
- Laboratorio de Fisiología, Hipoxia y Función Vascular, Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
| | - Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes, Punta Arenas, Chile
| | - Aníbal J Llanos
- Unidad de Fisiología y Fisiopatología Perinatal, Programa de Fisiopatología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,International Center for Andean Studies, Universidad de Chile, Santiago, Chile
| | - Roberto V Reyes
- Unidad de Fisiología y Fisiopatología Perinatal, Programa de Fisiopatología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,International Center for Andean Studies, Universidad de Chile, Santiago, Chile
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6
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Bon RS, Wright DJ, Beech DJ, Sukumar P. Pharmacology of TRPC Channels and Its Potential in Cardiovascular and Metabolic Medicine. Annu Rev Pharmacol Toxicol 2022; 62:427-446. [PMID: 34499525 DOI: 10.1146/annurev-pharmtox-030121-122314] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transient receptor potential canonical (TRPC) proteins assemble to form homo- or heterotetrameric, nonselective cation channels permeable to K+, Na+, and Ca2+. TRPC channels are thought to act as complex integrators of physical and chemical environmental stimuli. Although the understanding of essential physiological roles of TRPC channels is incomplete, their implication in various pathological mechanisms and conditions of the nervous system, kidneys, and cardiovascular system in combination with the lack of major adverse effects of TRPC knockout or TRPC channel inhibition is driving the search of TRPC channel modulators as potential therapeutics. Here, we review the most promising small-molecule TRPC channel modulators, the understanding of their mode of action, and their potential in the study and treatment of cardiovascular and metabolic disease.
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Affiliation(s)
- Robin S Bon
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom;
| | - David J Wright
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom;
| | - David J Beech
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom;
| | - Piruthivi Sukumar
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom;
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7
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Hunanyan L, Ghamaryan V, Makichyan A, Popugaeva E. Computer-Based Drug Design of Positive Modulators of Store-Operated Calcium Channels to Prevent Synaptic Dysfunction in Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms222413618. [PMID: 34948414 PMCID: PMC8707499 DOI: 10.3390/ijms222413618] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 11/25/2022] Open
Abstract
Store-operated calcium entry (SOCE) constitutes a fine-tuning mechanism responsible for the replenishment of intracellular stores. Hippocampal SOCE is regulated by store-operated channels (SOC) organized in tripartite complex TRPC6/ORAI2/STIM2. It is suggested that in neurons, SOCE maintains intracellular homeostatic Ca2+ concentration at resting conditions and is needed to support the structure of dendritic spines. Recent evidence suggests that positive modulators of SOC are prospective drug candidates to treat Alzheimer’s disease (AD) at early stages. Although STIM2 and ORAI2 are definitely involved in the regulation of nSOC amplitude and a play major role in AD pathogenesis, growing evidence suggest that it is not easy to target these proteins pharmacologically. Existing positive modulators of TRPC6 are unsuitable for drug development due to either bad pharmacokinetics or side effects. Thus, we concentrate the review on perspectives to develop specific nSOC modulators based on available 3D structures of TRPC6, ORAI2, and STIM2. We shortly describe the structural features of existing models and the methods used to prepare them. We provide commonly used steps applied for drug design based on 3D structures of target proteins that might be used to develop novel AD preventing therapy.
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Affiliation(s)
- Lernik Hunanyan
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia;
- Laboratory of Structural Bioinformatics, Institute of Biomedicine and Pharmacy, Russian-Armenian University, Yerevan 0051, Armenia; (V.G.); (A.M.)
| | - Viktor Ghamaryan
- Laboratory of Structural Bioinformatics, Institute of Biomedicine and Pharmacy, Russian-Armenian University, Yerevan 0051, Armenia; (V.G.); (A.M.)
| | - Ani Makichyan
- Laboratory of Structural Bioinformatics, Institute of Biomedicine and Pharmacy, Russian-Armenian University, Yerevan 0051, Armenia; (V.G.); (A.M.)
| | - Elena Popugaeva
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia;
- Correspondence:
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8
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Aaronson PI. Pulmonary hypertension associated with chronic hypoxia: just ASIC-ness? J Physiol 2021; 599:4731-4732. [PMID: 34533831 DOI: 10.1113/jp282325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Philip I Aaronson
- Department of Inflammation Biology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
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9
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Cross-Talk between Mechanosensitive Ion Channels and Calcium Regulatory Proteins in Cardiovascular Health and Disease. Int J Mol Sci 2021; 22:ijms22168782. [PMID: 34445487 PMCID: PMC8395829 DOI: 10.3390/ijms22168782] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/13/2021] [Accepted: 08/14/2021] [Indexed: 12/12/2022] Open
Abstract
Mechanosensitive ion channels are widely expressed in the cardiovascular system. They translate mechanical forces including shear stress and stretch into biological signals. The most prominent biological signal through which the cardiovascular physiological activity is initiated or maintained are intracellular calcium ions (Ca2+). Growing evidence show that the Ca2+ entry mediated by mechanosensitive ion channels is also precisely regulated by a variety of key proteins which are distributed in the cell membrane or endoplasmic reticulum. Recent studies have revealed that mechanosensitive ion channels can even physically interact with Ca2+ regulatory proteins and these interactions have wide implications for physiology and pathophysiology. Therefore, this paper reviews the cross-talk between mechanosensitive ion channels and some key Ca2+ regulatory proteins in the maintenance of calcium homeostasis and its relevance to cardiovascular health and disease.
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10
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Ion channels as convergence points in the pathology of pulmonary arterial hypertension. Biochem Soc Trans 2021; 49:1855-1865. [PMID: 34346486 PMCID: PMC8421048 DOI: 10.1042/bst20210538] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 12/17/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a fatal disease of the cardiopulmonary system that lacks curative treatments. The main pathological event in PAH is elevated vascular resistance in the pulmonary circulation, caused by abnormal vasoconstriction and vascular remodelling. Ion channels are key determinants of vascular smooth muscle tone and homeostasis, and four PAH channelopathies (KCNK3, ABCC8, KCNA5, TRPC6) have been identified so far. However, the contribution of ion channels in other forms of PAH, which account for the majority of PAH patients, has been less well characterised. Here we reason that a variety of triggers of PAH (e.g. BMPR2 mutations, hypoxia, anorectic drugs) that impact channel function may contribute to the onset of the disease. We review the molecular mechanisms by which these ‘extrinsic’ factors converge on ion channels and provoke their dysregulation to promote the development of PAH. Ion channels of the pulmonary vasculature are therefore promising therapeutic targets because of the modulation they provide to both vasomotor tone and proliferation of arterial smooth muscle cells.
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11
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The newborn sheep translational model for pulmonary arterial hypertension of the neonate at high altitude. J Dev Orig Health Dis 2021; 11:452-463. [PMID: 32705972 DOI: 10.1017/s2040174420000616] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chronic hypoxia during gestation induces greater occurrence of perinatal complications such as intrauterine growth restriction, fetal hypoxia, newborn asphyxia, and respiratory distress, among others. This condition may also cause a failure in the transition of the fetal to neonatal circulation, inducing pulmonary arterial hypertension of the neonate (PAHN), a syndrome that involves pulmonary vascular dysfunction, increased vasoconstrictor tone and pathological remodeling. As this syndrome has a relatively low prevalence in lowlands (~7 per 1000 live births) and very little is known about its prevalence and clinical evolution in highlands (above 2500 meters), our understanding is very limited. Therefore, studies on appropriate animal models have been crucial to comprehend the mechanisms underlying this pathology. Considering the strengths and weaknesses of any animal model of human disease is fundamental to achieve an effective and meaningful translation to clinical practice. The sheep model has been used to study the normal and abnormal cardiovascular development of the fetus and the neonate for almost a century. The aim of this review is to highlight the advances in our knowledge on the programming of cardiopulmonary function with the use of high-altitude newborn sheep as a translational model of PAHN.
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12
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Coburn RF. Coronary and cerebral metabolism-blood flow coupling and pulmonary alveolar ventilation-blood flow coupling may be disabled during acute carbon monoxide poisoning. J Appl Physiol (1985) 2020; 129:1039-1050. [PMID: 32853110 DOI: 10.1152/japplphysiol.00172.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Current evidence indicates that the toxicity of carbon monoxide (CO) poisoning results from increases in reactive oxygen species (ROS) generation plus tissue hypoxia resulting from decreases in capillary Po2 evoked by effects of increases in blood [carboxyhemoglobin] on the oxyhemoglobin dissociation curve. There has not been consideration of how increases in Pco could influence metabolism-blood flow coupling, a physiological mechanism that regulates the uniformity of tissue Po2, and alveolar ventilation-blood flow coupling, a mechanism that increases the efficiency of pulmonary O2 uptake. Using published data, I consider hypotheses that these coupling mechanisms, triggered by O2 and CO sensors located in arterial and arteriolar vessels in the coronary and cerebral circulations and in lung intralobar arteries, are disrupted during acute CO poisoning. These hypotheses are supported by calculations that show that the Pco in these vessels can reach levels during CO poisoning that would exert effects on signal transduction molecules involved in these coupling mechanisms.NEW & NOTEWORTHY This article introduces and supports a postulate that the tissue hypoxia component of carbon monoxide poisoning results in part from impairment of physiological adaptation mechanisms whereby tissues can match regional blood flow to O2 uptake, and the lung can match regional blood flow to alveolar ventilation.
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Affiliation(s)
- Ronald F Coburn
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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13
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Castillo-Galán S, Arenas GA, Reyes RV, Krause BJ, Iturriaga R. Stim-activated TRPC-ORAI channels in pulmonary hypertension induced by chronic intermittent hypoxia. Pulm Circ 2020; 10:13-22. [PMID: 33110495 PMCID: PMC7557718 DOI: 10.1177/2045894020941484] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/18/2020] [Indexed: 12/30/2022] Open
Abstract
Obstructive sleep apnea (OSA), a breathing disorder featured by chronic intermittent
hypoxia (CIH) is associated with pulmonary hypertension (PH). Rodents exposed to CIH
develop pulmonary vascular remodeling and PH, but the pathogenic mechanisms are not well
known. Overexpression of Stim-activated Transient Receptor Potential Channels (TRPC) and
Calcium Release-Activated Calcium Channel Protein (ORAI) TRPC-ORAI Ca2+
channels (STOC) has been involved in pulmonary vascular remodeling and PH in sustained
hypoxia. However, it is not known if CIH may change STOC levels. Accordingly, we studied
the effects of CIH on the expression of STOC subunits in the lung and if these changes
paralleled the progression of the vascular pulmonary remodeling and PH in a preclinical
model of OSA. Male Sprague-Dawley rats (∼200 g) were exposed to CIH (5%O2, 12
times/h for 8 h) for 14, 21, and 28 days. We measured right ventricular systolic pressure
(RVSP), cardiac morphometry with MRI, pulmonary vascular remodeling, and wire-myographic
arterial responses to KCl and endothelin-1 (ET-1). Pulmonary RNA and protein STOC levels
of TRPC1, TRPC4, TRPC6, ORAI 1, ORAI 2, and STIM1 subunits were measured by qPCR and
western blot, and results were compared with age-matched controls. CIH elicited a
progressive increase of RVSP and vascular contractile responses to KCl and ET-1, leading
to vascular remodeling and augmented right ventricular ejection fraction, which was
significant at 28 days of CIH. The levels of TRPC1, TRPC4, TRPC 6, ORAI 1, and STIM 1
channels increased following CIH, and some of them paralleled morphologic and functional
changes. Our findings show that CIH increased pulmonary STOC expression, paralleling
vascular remodeling and PH.
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Affiliation(s)
- Sebastian Castillo-Galán
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - German A Arenas
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Roberto V Reyes
- Laboratorio de Bioquímica y Biología Molecular de la Hipoxia, Universidad de Chile, Santiago, Chile
| | - Bernardo J Krause
- Instituto de Ciencias de la Salud, Universidad de O'Higgins, Rancagua, Chile
| | - Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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14
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Evans AM. On a Magical Mystery Tour with 8-Bromo-Cyclic ADP-Ribose: From All-or-None Block to Nanojunctions and the Cell-Wide Web. Molecules 2020; 25:E4768. [PMID: 33081414 PMCID: PMC7587525 DOI: 10.3390/molecules25204768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/08/2020] [Indexed: 11/16/2022] Open
Abstract
A plethora of cellular functions are controlled by calcium signals, that are greatly coordinated by calcium release from intracellular stores, the principal component of which is the sarco/endooplasmic reticulum (S/ER). In 1997 it was generally accepted that activation of various G protein-coupled receptors facilitated inositol-1,4,5-trisphosphate (IP3) production, activation of IP3 receptors and thus calcium release from S/ER. Adding to this, it was evident that S/ER resident ryanodine receptors (RyRs) could support two opposing cellular functions by delivering either highly localised calcium signals, such as calcium sparks, or by carrying propagating, global calcium waves. Coincidentally, it was reported that RyRs in mammalian cardiac myocytes might be regulated by a novel calcium mobilising messenger, cyclic adenosine diphosphate-ribose (cADPR), that had recently been discovered by HC Lee in sea urchin eggs. A reputedly selective and competitive cADPR antagonist, 8-bromo-cADPR, had been developed and was made available to us. We used 8-bromo-cADPR to further explore our observation that S/ER calcium release via RyRs could mediate two opposing functions, namely pulmonary artery dilation and constriction, in a manner seemingly independent of IP3Rs or calcium influx pathways. Importantly, the work of others had shown that, unlike skeletal and cardiac muscles, smooth muscles might express all three RyR subtypes. If this were the case in our experimental system and cADPR played a role, then 8-bromo-cADPR would surely block one of the opposing RyR-dependent functions identified, or the other, but certainly not both. The latter seemingly implausible scenario was confirmed. How could this be, do cells hold multiple, segregated SR stores that incorporate different RyR subtypes in receipt of spatially segregated signals carried by cADPR? The pharmacological profile of 8-bromo-cADPR action supported not only this, but also indicated that intracellular calcium signals were delivered across intracellular junctions formed by the S/ER. Not just one, at least two. This article retraces the steps along this journey, from the curious pharmacological profile of 8-bromo-cADPR to the discovery of the cell-wide web, a diverse network of cytoplasmic nanocourses demarcated by S/ER nanojunctions, which direct site-specific calcium flux and may thus coordinate the full panoply of cellular processes.
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Grants
- 01/A/S/07453 Biotechnology and Biological Sciences Research Council
- WT046374 , WT056423, WT070772, WT074434, WT081195AIA, WT212923, WT093147 Wellcome Trust
- PG/10/95/28657 British Heart Foundation
- FS/03/033/15432, FS/05/050, PG/05/128/19884, RG/12/14/29885, PG/10/95/28657 British Heart Foundation
- RG/12/14/29885 British Heart Foundation
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Affiliation(s)
- A Mark Evans
- Centre for Discovery Brain Sciences and Cardiovascular Science, Edinburgh Medical School, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
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15
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Brito J, Siques P, Pena E. Long-term chronic intermittent hypoxia: a particular form of chronic high-altitude pulmonary hypertension. Pulm Circ 2020; 10:5-12. [PMID: 33110494 PMCID: PMC7557688 DOI: 10.1177/2045894020934625] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/26/2020] [Indexed: 12/19/2022] Open
Abstract
In some subjects, high-altitude hypobaric hypoxia leads to high-altitude pulmonary
hypertension. The threshold for the diagnosis of high-altitude pulmonary hypertension is a
mean pulmonary artery pressure of 30 mmHg, even though for general pulmonary hypertension
is ≥25 mmHg. High-altitude pulmonary hypertension has been associated with high hematocrit
findings (chronic mountain sickness), and although these are two separate entities, they
have a synergistic effect that should be considered. In recent years, a new condition
associated with high altitude was described in South America named long-term chronic
intermittent hypoxia and has appeared in individuals who commute to work at high altitude
but live and rest at sea level. In this review, we discuss the initial epidemiological
pattern from the early studies done in Chile, the clinical presentation and possible
molecular mechanism and a discussion of the potential management of this condition.
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Affiliation(s)
- Julio Brito
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and Its Health Sequelae, Hamburg, Germany
| | - Patricia Siques
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and Its Health Sequelae, Hamburg, Germany
| | - Eduardo Pena
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and Its Health Sequelae, Hamburg, Germany
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16
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Reyes RV, Herrera EA, Ebensperger G, Sanhueza EM, Giussani DA, Llanos AJ. Perinatal cardiopulmonary adaptation to the thin air of the Alto Andino by a native Altiplano dweller, the llama. J Appl Physiol (1985) 2020; 129:152-161. [PMID: 32584666 DOI: 10.1152/japplphysiol.00800.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Most mammals have a poor tolerance to hypoxia, and prolonged O2 restriction can lead to organ injury, particularly during fetal and early postnatal life. Nevertheless, the llama (Lama Glama) has evolved efficient mechanisms to adapt to acute and chronic perinatal hypoxia. One striking adaptation is the marked peripheral vasoconstriction measured in the llama fetus in response to acute hypoxia, which allows efficient redistribution of cardiac output toward the fetal heart and adrenal glands. This strong peripheral vasoconstrictor tone is triggered by a carotid body reflex and critically depends on α-adrenergic signaling. A second adaptation is the ability of the llama fetus to protect its brain against hypoxic damage. During hypoxia, in the llama fetus there is no significant increase in brain blood flow. Instead, there is a fall in brain O2 consumption and temperature, together with a decrease of Na+-K+-ATPase activity and Na+ channels expression, protecting against seizures and neuronal death. Finally, the newborn llama does not develop pulmonary hypertension in response to chronic hypoxia. In addition to maintaining basal pulmonary arterial pressure at normal levels the pulmonary arterial pressor response to acute hypoxia is lower in highland than in lowland llamas. The protection against hypoxic pulmonary arterial hypertension and pulmonary contractile hyperreactivity is partly due to increased hemoxygenase-carbon monoxide signaling and decreased Ca2+ sensitization in the newborn llama pulmonary vasculature. These three striking physiological adaptations of the llama allow this species to live and thrive under the chronic influence of the hypobaric hypoxia of life at high altitude.
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Affiliation(s)
- R V Reyes
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,International Center for Andean Studies (INCAS), Universidad de Chile, Santiago, Chile
| | - E A Herrera
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,International Center for Andean Studies (INCAS), Universidad de Chile, Santiago, Chile
| | - G Ebensperger
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,International Center for Andean Studies (INCAS), Universidad de Chile, Santiago, Chile
| | - E M Sanhueza
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - D A Giussani
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - A J Llanos
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,International Center for Andean Studies (INCAS), Universidad de Chile, Santiago, Chile
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17
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Gomez AP, Moreno MJ, Hernández A. Adventitial growth and lung connective tissue growth factor expression in pulmonary arterioles due to hypobaric hypoxia in broilers. Poult Sci 2020; 99:1832-1837. [PMID: 32241463 PMCID: PMC7587700 DOI: 10.3382/ps/pez157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 03/11/2019] [Indexed: 11/25/2022] Open
Abstract
Forty broilers maintained under natural hypobaric hypoxia (2,638 m above sea level) and 20 maintained under relative normoxia (460 m above sea level) were selected as pulmonary hypertensive (PHB) and nonpulmonary hypertensive (NPHB), to estimate the degree of the adventitial vascular thickness in lung arterioles and connective tissue growth factor (CTGF) expression in lung. In each group, the adventitial thickness (%AT) of 20 arterioles with 100 to 250 μm of external diameter was measured in lung samples of 24 and 42-day-old broilers. Also, mRNA extraction and real-time reverse transcription-PCR analysis were used to measure lung CTGF expression. The %AT was higher in PHB at 42 D as compared to NPHB at both ages and PHB at 24 D; however, the same differences were not evidenced at 24 D. In the 2 ages evaluated, differences were observed in the %AT between broilers under hypobaric hypoxia (PHB and NPHB) and under relative normoxia (P < 0.01). In broilers subjected to relative normoxia, no significant differences were found at any of the 2 ages. The expression levels of CTGF mRNA were higher in PHB compared to NPHB at the 2 ages. The %AT was higher in PHB with high levels of expression of CTGF mRNA than those NPHB with low expression of CTGF mRNA. This study showed that adventitial thickening is part of the pulmonary hypertension (PH) physiopathology in broilers exposed to hypobaric hypoxia, in which CTGF appears to be a fibrosis enhancer. Although present data suggest that adventitial engrossment could be a time-dependent process, individual susceptibility and the variable time-course of PH pathophysiology have to be considered.
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Affiliation(s)
- A P Gomez
- Facultad de Medicina Veterinaria y de Zootecnia, Universidad Nacional de Colombia, Bogotá DC 111311, Colombia
| | - M J Moreno
- Facultad de Medicina Veterinaria y de Zootecnia, Universidad Nacional de Colombia, Bogotá DC 111311, Colombia
| | - A Hernández
- Facultad de Medicina Veterinaria y de Zootecnia, Universidad Nacional de Colombia, Bogotá DC 111311, Colombia.
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18
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Jasemi SV, Khazaei H, Aneva IY, Farzaei MH, Echeverría J. Medicinal Plants and Phytochemicals for the Treatment of Pulmonary Hypertension. Front Pharmacol 2020; 11:145. [PMID: 32226378 PMCID: PMC7080987 DOI: 10.3389/fphar.2020.00145] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/04/2020] [Indexed: 12/18/2022] Open
Abstract
Background Pulmonary hypertension (PH) is a progressive disease that is associated with pulmonary arteries remodeling, right ventricle hypertrophy, right ventricular failure and finally death. The present study aims to review the medicinal plants and phytochemicals used for PH treatment in the period of 1994 – 2019. Methods PubMed, Cochrane and Scopus were searched based on pulmonary hypertension, plant and phytochemical keywords from August 23, 2019. All articles that matched the study based on title and abstract were collected, non-English, repetitive and review studies were excluded. Results Finally 41 studies remained from a total of 1290. The results show that many chemical treatments considered to this disease are ineffective in the long period because they have a controlling role, not a therapeutic one. On the other hand, plants and phytochemicals could be more effective due to their action on many mechanisms that cause the progression of PH. Conclusion Studies have shown that herbs and phytochemicals used to treat PH do their effects from six mechanisms. These mechanisms include antiproliferative, antioxidant, antivascular remodeling, anti-inflammatory, vasodilatory and apoptosis inducing actions. According to the present study, many of these medicinal plants and phytochemicals can have effects that are more therapeutic than chemical drugs if used appropriately.
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Affiliation(s)
- Seyed Vahid Jasemi
- Department of Internal Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Hosna Khazaei
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Ina Yosifova Aneva
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Mohammad Hosein Farzaei
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Javier Echeverría
- Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
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19
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Type 2 inositol 1,4,5-trisphosphate receptor inhibits the progression of pulmonary arterial hypertension via calcium signaling and apoptosis. Heart Vessels 2018; 34:724-734. [PMID: 30460575 DOI: 10.1007/s00380-018-1304-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/09/2018] [Indexed: 12/21/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a progressive disease associated with vasoconstriction and remodeling. Intracellular Ca2+ signaling regulates the contraction of pulmonary arteries and the proliferation of pulmonary arterial smooth muscle cells (PASMCs); however, it is not clear which molecules related to Ca2+ signaling contribute to the progression of PAH. In this study, we found the specific expression of type 2 inositol 1,4,5-trisphosphate receptor (IP3R2), which is an intracellular Ca2+ release channel, on the sarco/endoplasmic reticulum in mouse PASMCs, and demonstrated its inhibitory role in the progression of PAH using a chronic hypoxia-induced PAH mouse model. After chronic hypoxia exposure, IP3R2-/- mice exhibited the significant aggravation of PAH, as determined by echocardiography and right ventricular hypertrophy, with significantly greater medial wall thickness by immunohistochemistry than that of wild-type mice. In IP3R2-/- murine PASMCs with chronic hypoxia, a TUNEL assay revealed the significant suppression of apoptosis, whereas there was no significant change in proliferation. Thapsigargin-induced store-operated Ca2+ entry (SOCE) was significantly enhanced in IP3R2-/- PASMCs in both normoxia and hypoxia based on in vitro fluorescent Ca2+ imaging. Furthermore, the enhancement of SOCE in IP3R2-/- PASMCs was remarkably suppressed by the addition of DPB162-AE, an inhibitor of the stromal-interacting molecule (STIM)-Orai complex which is about 100 times more potent than 2-APB. Our results indicate that IP3R2 may inhibit the progression of PAH by promoting apoptosis and inhibiting SOCE via the STIM-Orai pathway in PASMCs. These findings suggest a previously undetermined role of IP3R in the development of PAH and may contribute to the development of targeted therapies.
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