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Eliezeck M, Guedes Jesus IC, Scalzo SA, Sanches BDL, Silva KSC, Costa M, Mesquita T, Rocha-Resende C, Szawka RE, Guatimosim S. β-Adrenergic signaling drives structural and functional maturation of mouse cardiomyocytes. Am J Physiol Cell Physiol 2024; 326:C1334-C1344. [PMID: 38557356 DOI: 10.1152/ajpcell.00426.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 02/28/2024] [Accepted: 03/14/2024] [Indexed: 04/04/2024]
Abstract
Cardiac maturation represents the last phase of heart development and is characterized by morphofunctional alterations that optimize the heart for efficient pumping. Its understanding provides important insights into cardiac regeneration therapies. Recent evidence implies that adrenergic signals are involved in the regulation of cardiac maturation, but the mechanistic underpinnings involved in this process are poorly understood. Herein, we explored the role of β-adrenergic receptor (β-AR) activation in determining structural and functional components of cardiomyocyte maturation. Temporal characterization of tyrosine hydroxylase and norepinephrine levels in the mouse heart revealed that sympathetic innervation develops during the first 3 wk of life, concurrent with the rise in β-AR expression. To assess the impact of adrenergic inhibition on maturation, we treated mice with propranolol, isolated cardiomyocytes, and evaluated morphofunctional parameters. Propranolol treatment reduced heart weight, cardiomyocyte size, and cellular shortening, while it increased the pool of mononucleated myocytes, resulting in impaired maturation. No changes in t-tubules were observed in cells from propranolol mice. To establish a causal link between β-AR signaling and cardiomyocyte maturation, mice were subjected to sympathectomy, followed or not by restoration with isoproterenol treatment. Cardiomyocytes from sympathectomyzed mice recapitulated the salient immaturity features of propranolol-treated mice, with the additional loss of t-tubules. Isoproterenol rescued the maturation deficits induced by sympathectomy, except for the t-tubule alterations. Our study identifies the β-AR stimuli as a maturation promoting signal and implies that this pathway can be modulated to improve cardiac regeneration therapies.NEW & NOTEWORTHY Maturation involves a series of morphofunctional alterations vital to heart development. Its regulatory mechanisms are only now being unveiled. Evidence implies that adrenergic signaling regulates cardiac maturation, but the mechanisms are poorly understood. To address this point, we blocked β-ARs or performed sympathectomy followed by rescue experiments with isoproterenol in neonatal mice. Our study identifies the β-AR stimuli as a maturation signal for cardiomyocytes and highlights the importance of this pathway in cardiac regeneration therapies.
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Affiliation(s)
- Marcos Eliezeck
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Itamar Couto Guedes Jesus
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Sérgio A Scalzo
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Bruno de Lima Sanches
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Kaoma Stephani Costa Silva
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mateus Costa
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Thássio Mesquita
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Cibele Rocha-Resende
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Raphael E Szawka
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Bruno AS, Castor RGM, Berg B, Dos Reis Costa DEF, Monteiro ALL, Scalzo S, Oliveira KCM, Bello FLM, Aguiar GC, Melo MB, Santos RAS, Bonaventura D, Guatimosim S, Castor MGM, Ferreira AJ, Cau SBA. Cardiac disturbances and changes in tissue cytokine levels in mice fed with a high-refined carbohydrate diet. Cytokine 2023; 166:156192. [PMID: 37054665 DOI: 10.1016/j.cyto.2023.156192] [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: 12/21/2022] [Accepted: 03/24/2023] [Indexed: 04/15/2023]
Abstract
AIMS The consumption of highly refined carbohydrates increases systemic inflammatory markers, but its potential to exert direct myocardial inflammation is uncertain. Herein, we addressed the impact of a high-refined carbohydrate (HC) diet on mice heart and local inflammation over time. MAIN METHODS BALB/c mice were fed with a standard chow (control) or an isocaloric HC diet for 2, 4, or 8 weeks (HC groups), in which the morphometry of heart sections and contractile analyses by invasive catheterization and Langendorff-perfused hearts were assessed. Cytokines levels by ELISA, matrix metalloproteinase (MMP) activity by zymography, in situ reactive oxygen species (ROS) staining and lipid peroxidation-induced TBARS levels, were also determined. KEY FINDINGS HC diet fed mice displayed left ventricular hypertrophy and interstitial fibrosis in all times analyzed, which was confirmed by echocardiographic analyses of 8HC group. Impaired contractility indices of HC groups were observed by left ventricular catheterization, whereas ex vivo and in vitro indices of contraction under isoprenaline-stimulation were higher in HC-fed mice compared with controls. Peak levels of TNF-α, TGF-β, ROS, TBARS, and MMP-2 occur independently of HC diet time. However, a long-lasting local reduction of the anti-inflammatory cytokine IL-10 was found, which was linearly correlated to the decline of systolic function in vivo. SIGNIFICANCE Altogether, the results indicate that short-term consumption of HC diet negatively impacts the balance of anti-inflammatory defenses and proinflammatory/profibrotic mediators in the heart, which can contribute to HC diet-induced morphofunctional cardiac alterations.
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Affiliation(s)
- Alexandre Santos Bruno
- Departments of Pharmacology, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Renata Gomes Miranda Castor
- Departments of Pharmacology, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Bárbara Berg
- Departments of Pharmacology, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | | | - André Luis Lima Monteiro
- Departments of Physiology & Biophysics, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Sérgio Scalzo
- Departments of Physiology & Biophysics, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | | | | | - Grazielle Cordeiro Aguiar
- Departments of Morphology, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Marcos Barrouin Melo
- Departments of Physiology & Biophysics, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Robson Augusto Souza Santos
- Departments of Physiology & Biophysics, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Daniella Bonaventura
- Departments of Pharmacology, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Silvia Guatimosim
- Departments of Physiology & Biophysics, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Marina Gomes Miranda Castor
- Departments of Pharmacology, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Anderson Jose Ferreira
- Departments of Morphology, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil
| | - Stefany Bruno Assis Cau
- Departments of Pharmacology, Institute of Biological Science, Federal University of Minas Gerais, MG, Brazil.
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Abstract
This protocol provides instructions to acquire high-quality cellular contractility data from adult, neonatal, and human induced pluripotent stem cell-derived cardiomyocytes. Contractility parameters are key to unravel mechanisms underlying cardiac pathologies, yet difficulties in acquiring data can compromise measurement accuracy and reproducibility. We provide optimized steps for microscope and camera setup, as well as cellular selection criteria for different cardiomyocyte cell types, aiming to obtain robust and reliable data. Moreover, we use CONTRACTIONWAVE software to analyze and show the optimized results. For complete details on the use and execution of this profile, please refer to Scalzo et al. (2021).
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Guimaraes DA, Aquino NSS, Rocha-Resende C, Jesus ICG, Silva MM, Scalzo SA, Fonseca RC, Durand MT, Pereira V, Tezini GCSV, Oliveira A, Prado VF, Stefanon I, Salgado HC, Prado MAM, Szawka RE, Guatimosim S. Neuronal cholinergic signaling constrains norepinephrine activity in the heart. Am J Physiol Cell Physiol 2022; 322:C794-C801. [PMID: 35264016 DOI: 10.1152/ajpcell.00031.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is well known that cholinergic hypofunction contributes to cardiac pathology; yet, the mechanisms involved remain unclear. Our previous publication has shown that genetically engineered model of cholinergic deficit, the vesicular acetylcholine transporter knockdown homozygous (VAChT KDHOM) mice exhibit pathological cardiac remodeling and a gradual increase in cardiac mass with aging. Given that an increase in cardiac mass is often caused by adrenergic hyperactivity, we hypothesized that VAChT KDHOM mice might have an increase in cardiac norepinephrine (NE) levels. We thus investigated the temporal changes in NE content in the heart from 3, 6 and 12 month-old VAChT mutants. Interestingly, mice with cholinergic hypofunction showed a gradual elevation in cardiac NE content, which was already increased at 6 months of age. Consistent with this finding, 6 month-old VAChT KDHOM mice showed enhanced sympathetic activity and a greater abundance of tyrosine hydroxylase positive sympathetic nerves in the heart. VAChT mutants exhibited an increase in peak calcium transient, and mitochondrial oxidative stress in cardiomyocytes along with enhanced GRK5 and NFAT staining in the heart. These are known targets of adrenergic signaling in the cell. Moreover, vagotomized-mice displayed an increase in cardiac NE content confirming the data obtained in VAChT KDHOM mice. Establishing a causal relationship between acetylcholine and NE, VAChT KDHOM mice treated with pyridostigmine, a cholinesterase inhibitor, showed reduced cardiac NE content, rescuing the phenotype. Our findings unveil a yet unrecognized role of cholinergic signaling as a modulator of cardiac NE, providing novel insights into the mechanisms that drive autonomic imbalance.
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Affiliation(s)
- Diogo A Guimaraes
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Nayara S S Aquino
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Cibele Rocha-Resende
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Itamar C G Jesus
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Mário Morais Silva
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Sergio A Scalzo
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Roberta Cristelli Fonseca
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Marina T Durand
- Universidade de Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Vanessa Pereira
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - André Oliveira
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Vânia F Prado
- Robarts Research Institute, The University of Western Ontario, Department of Physiology 1and Pharmacology, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Ivanita Stefanon
- Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, Espirito Santo, Brazil
| | - Helio C Salgado
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Marco Antonio Máximo Prado
- Robarts Research Institute, The University of Western Ontario, Department of Physiology 1and Pharmacology, Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Raphael E Szawka
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Unraveling the Cardiac Effects Induced by Carvacrol in Spontaneously Hypertensive Rats: Involvement of Transient Receptor Potential Melastatin Subfamily 4 and 7 Channels. J Cardiovasc Pharmacol 2022; 79:206-216. [PMID: 35099165 DOI: 10.1097/fjc.0000000000001165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/05/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT Accumulating evidence indicates that transient receptor potential (TRP) channels are involved in the pathophysiological process in the heart, and monoterpenes, such as carvacrol, are able to modulate these channels activity. In this article, our purpose was to evaluate the direct cardiac effect of carvacrol on the contractility of cardiomyocytes and isolated right atria from spontaneously hypertensive and Wistar Kyoto rats. In this way, in vitro experiments were used to evaluate the ventricular cardiomyocytes contractility and the Ca2+ transient measuring, in addition to heart rhythm in the right atria. The role of TRPM channels in carvacrol-mediated cardiac activities was also investigated. The results demonstrated that carvacrol induced a significant reduction in ventricular cell contractility, without changes in transient Ca2+. In addition, carvacrol promoted a significant negative chronotropic response in spontaneously hypertensive and Wistar Kyoto rats' atria. Selective blockage of TRPM channels suggests the involvement of TRP melastatin subfamily 2 (TRPM2), TRPM4, and TRPM7 in the carvacrol-mediated cardiac effects. In silico studies were conducted to further investigate the putative role of TRPM4 in carvacrol-mediated cardiac action. FTMap underscores a conserved pocket in both TRPM4 and TRPM7, revealing a potential carvacrol binding site, and morphological similarity analysis demonstrated that carvacrol shares a more than 85% similarity to 9-phenanthrol. Taken together, these results suggest that carvacrol has direct cardiac actions, leading to reduced cellular contractility and inducing a negative chronotropic effect, which may be related to TRPM7 and TRPM4 modulation.
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6
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Teixeira VP, Miranda K, Scalzo S, Rocha-Resende C, Silva MM, Tezini GCSV, Melo MB, Souza-Neto FP, Silva KSC, Jesus ICG, Santos AK, de Oliveira M, Szawka RE, Salgado HC, Prado MAM, Poletini MO, Guatimosim S. Increased cholinergic activity under conditions of low estrogen leads to adverse cardiac remodeling. Am J Physiol Cell Physiol 2021; 320:C602-C612. [PMID: 33296286 DOI: 10.1152/ajpcell.00142.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023]
Abstract
Cholinesterase inhibitors are used in postmenopausal women for the treatment of neurodegenerative diseases. Despite their widespread use in the clinical practice, little is known about the impact of augmented cholinergic signaling on cardiac function under reduced estrogen conditions. To address this gap, we subjected a genetically engineered murine model of systemic vesicular acetylcholine transporter overexpression (Chat-ChR2) to ovariectomy and evaluated cardiac parameters. Left-ventricular function was similar between Chat-ChR2 and wild-type (WT) mice. Following ovariectomy, WT mice showed signs of cardiac hypertrophy. Conversely, ovariectomized (OVX) Chat-ChR2 mice evolved to cardiac dilation and failure. Transcript levels for cardiac stress markers atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) were similarly upregulated in WT/OVX and Chat-ChR2/OVX mice. 17β-Estradiol (E2) treatment normalized cardiac parameters in Chat-ChR2/OVX to the Chat-ChR2/SHAM levels, providing a link between E2 status and the aggravated cardiac response in this model. To investigate the cellular basis underlying the cardiac alterations, ventricular myocytes were isolated and their cellular area and contractility were assessed. Myocytes from WT/OVX mice were wider than WT/SHAM, an indicative of concentric hypertrophy, but their fractional shortening was similar. Conversely, Chat-ChR2/OVX myocytes were elongated and presented contractile dysfunction. E2 treatment again prevented the structural and functional changes in Chat-ChR2/OVX myocytes. We conclude that hypercholinergic mice under reduced estrogen conditions do not develop concentric hypertrophy, a critical compensatory adaptation, evolving toward cardiac dilation and failure. This study emphasizes the importance of understanding the consequences of cholinesterase inhibition, used clinically to treat dementia, for cardiac function in postmenopausal women.
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MESH Headings
- Acetylcholine/metabolism
- Animals
- Cholinergic Fibers/metabolism
- Estradiol/pharmacology
- Estrogen Replacement Therapy
- Estrogens/deficiency
- Female
- Heart/innervation
- Heart Rate
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Hypertrophy, Left Ventricular/prevention & control
- Mice, Inbred C57BL
- Mice, Transgenic
- Myocardial Contraction
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Ovariectomy
- Signal Transduction
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/pathology
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Dysfunction, Left/prevention & control
- Ventricular Function, Left/drug effects
- Ventricular Remodeling/drug effects
- Vesicular Acetylcholine Transport Proteins/genetics
- Vesicular Acetylcholine Transport Proteins/metabolism
- Mice
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Affiliation(s)
- Vanessa P Teixeira
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Kiany Miranda
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Sergio Scalzo
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Cibele Rocha-Resende
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Mário Morais Silva
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Geisa C S V Tezini
- Ribeirão Preto Medical School, Universidade de São Paulo, Riberão Preto, São Paulo, Brazil
| | - Marcos B Melo
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Fernando Pedro Souza-Neto
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Kaoma S C Silva
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Itamar C G Jesus
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Anderson K Santos
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Mauro de Oliveira
- Ribeirão Preto Medical School, Universidade de São Paulo, Riberão Preto, São Paulo, Brazil
| | - Raphael E Szawka
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Helio C Salgado
- Ribeirão Preto Medical School, Universidade de São Paulo, Riberão Preto, São Paulo, Brazil
| | - Marco Antonio Máximo Prado
- Robarts Research Institute, Department of Physiology and Pharmacology and Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
| | - Maristela O Poletini
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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7
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Braga TC, de Jesus ICG, Soares KV, Guatimosim S, da Silva Neto L, da-Silva CJ, Modolo LV, Menezes Filho JER, Rhana P, Cruz JS, de Fátima Â. A novel H2S releasing-monastrol hybrid (MADTOH) inhibits L-type calcium channels. NEW J CHEM 2021. [DOI: 10.1039/d0nj04415f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A new alleged monastrol-H2S releasing hybrid, named MADTOH, was designed based on the structure of monastrol (M) and 5-(4-hydroxyphenyl)-3H-1,2-dithiole-3-thione (ADTOH) and synthesized in 7.8% overall yield.
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Affiliation(s)
| | - Itamar Couto Guedes de Jesus
- Departamento de Fisiologia e Biofísica
- Instituto de Ciências Biológicas
- Universidade Federal de Minas Gerais
- Belo Horizonte
- Brazil
| | | | - Silvia Guatimosim
- Departamento de Fisiologia e Biofísica
- Instituto de Ciências Biológicas
- Universidade Federal de Minas Gerais
- Belo Horizonte
- Brazil
| | | | - Cristiane Jovelina da-Silva
- Departamento de Botânica
- Instituto de Ciências Biológicas
- Universidade Federal de Minas Gerais
- Belo Horizonte
- Brazil
| | - Luzia Valentina Modolo
- Departamento de Botânica
- Instituto de Ciências Biológicas
- Universidade Federal de Minas Gerais
- Belo Horizonte
- Brazil
| | | | - Paula Rhana
- Departamento de Bioquímica e Imunologia
- Instituto de Ciências Biológicas
- Universidade Federal de Minas Gerais
- Belo Horizonte
- Brazil
| | - Jader Santos Cruz
- Departamento de Bioquímica e Imunologia
- Instituto de Ciências Biológicas
- Universidade Federal de Minas Gerais
- Belo Horizonte
- Brazil
| | - Ângelo de Fátima
- Departamento de Química
- Universidade Federal de Minas Gerais
- Belo Horizonte
- Brazil
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8
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Silva MM, de Souza-Neto FP, Jesus ICGD, Gonçalves GK, Santuchi MDC, Sanches BDL, de Alcântara-Leonídio TC, Melo MB, Vieira MAR, Guatimosim S, Santos RAS, da Silva RF. Alamandine improves cardiac remodeling induced by transverse aortic constriction in mice. Am J Physiol Heart Circ Physiol 2021; 320:H352-H363. [PMID: 33124885 DOI: 10.1152/ajpheart.00328.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 09/30/2020] [Accepted: 10/21/2020] [Indexed: 12/30/2022]
Abstract
Alamandine is the newest identified peptide of the renin-angiotensin system (RAS) and has protective effects in the cardiovascular system. Although the involvement of classical RAS components in the genesis and progression of cardiac remodeling is well known, less is known about the effects of alamandine. Therefore, in the present study we investigated the effects of alamandine on cardiac remodeling induced by transverse aortic constriction (TAC) in mice. Male mice (C57BL/6), 10-12 wk of age, were divided into three groups: sham operated, TAC, and TAC + ALA (30 µg/kg/day alamandine for 14 days). The TAC surgery was performed under ketamine and xylazine anesthesia. At the end of treatment, the animals were submitted to echocardiographic examination and subsequently euthanized for tissue collection. TAC induced myocyte hypertrophy, collagen deposition, and the expression of matrix metalloproteinase (MMP)-2 and transforming growth factor (TGF)-β in the left ventricle. These markers of cardiac remodeling were reduced by oral treatment with alamandine. Western blotting analysis showed that alamandine prevents the increase in ERK1/2 phosphorylation and reverts the decrease in 5'-adenosine monophosphate-activated protein kinase (AMPK)α phosphorylation induced by TAC. Although both TAC and TAC + ALA increased SERCA2 expression, the phosphorylation of phospholamban in the Thr17 residue was increased solely in the alamandine-treated group. The echocardiographic data showed that there are no functional or morphological alterations after 2 wk of TAC. Alamandine treatment prevents myocyte hypertrophy and cardiac fibrosis induced by TAC. Our results reinforce the cardioprotective role of alamandine and highlight its therapeutic potential for treating heart diseases related to pressure overload conditions.NEW & NOTEWORTHY Alamandine is the newest identified component of the renin-angiotensin system protective arm. Considering the beneficial effects already described so far, alamandine is a promising target for cardiovascular disease treatment. We demonstrated for the first time that alamandine improves many aspects of cardiac remodeling induced by pressure overload, including cell hypertrophy, fibrosis, and oxidative stress markers.
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Affiliation(s)
- Mário Morais Silva
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | | | - Gleisy Kelly Gonçalves
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Bruno de Lima Sanches
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Marcos Barrouin Melo
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Silvia Guatimosim
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
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9
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Ke Q, Liu F, Tang Y, Chen J, Hu H, Sun X, Tan W. The protective effect of isosteviol sodium on cardiac function and myocardial remodelling in transverse aortic constriction rat. J Cell Mol Med 2021; 25:1166-1177. [PMID: 33336505 PMCID: PMC7812303 DOI: 10.1111/jcmm.16182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/10/2020] [Accepted: 11/25/2020] [Indexed: 11/30/2022] Open
Abstract
Pathological hypertrophy contributes to heart failure and there is not quite effective treatment to invert this process. Isosteviol has been shown to protect the heart against ischaemia-reperfusion injury and isoproterenol-induced cardiac hypertrophy, but its effect on pressure overload-induced cardiac hypertrophy is still unknown. Pressure overload induced by transverse aortic constriction (TAC) causes cardiac hypertrophy in rats to mimic the pathological condition in human. This study examined the effects of isosteviol sodium (STVNa) on cardiac hypertrophy by the TAC model and cellular assays in vitro. Cardiac function test, electrocardiogram analysis and histological analysis were conducted. The effects of STVNa on calcium transient of the adult rat ventricular cells and the proliferation of neonatal rat cardiac fibroblasts were also studied in vitro. Cardiac hypertrophy was observed after 3-week TAC while the extensive cardiac dysfunction and electronic remodelling were observed after 9-week TAC. Both STVNa and sildenafil (positive drug) treatment reversed the two process, but STVNa appeared to be more superior in some aspects and did not change calcium transient considerably. STVNa also reversed TAC-induced cardiac fibrosis in vivo and TGF-β1-induced fibroblast proliferation in vitro. Moreover, STVNa, but not sildenafil, reversed impairment of the autonomic nervous system induced by 9-week TAC.
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Affiliation(s)
- Qingjin Ke
- Institute of Biomedical and Pharmaceutical SciencesGuangdong University of TechnologyGuangzhouChina
| | - Fei Liu
- Institute of Biomedical and Pharmaceutical SciencesGuangdong University of TechnologyGuangzhouChina
| | - Yuxin Tang
- Institute of Biomedical and Pharmaceutical SciencesGuangdong University of TechnologyGuangzhouChina
| | - Jiedi Chen
- Institute of Biomedical and Pharmaceutical SciencesGuangdong University of TechnologyGuangzhouChina
| | - Hui Hu
- Institute of Biomedical and Pharmaceutical SciencesGuangdong University of TechnologyGuangzhouChina
| | - Xiaoou Sun
- Institute of Biomedical and Pharmaceutical SciencesGuangdong University of TechnologyGuangzhouChina
| | - Wen Tan
- Institute of Biomedical and Pharmaceutical SciencesGuangdong University of TechnologyGuangzhouChina
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10
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Goméz-Mendoza DP, Lemos RP, Jesus ICG, Gorshkov V, McKinnie SMK, Vederas JC, Kjeldsen F, Guatimosim S, Santos RA, Pimenta AMC, Verano-Braga T. Moving Pieces in a Cellular Puzzle: A Cryptic Peptide from the Scorpion Toxin Ts14 Activates AKT and ERK Signaling and Decreases Cardiac Myocyte Contractility via Dephosphorylation of Phospholamban. J Proteome Res 2020; 19:3467-3477. [PMID: 32597192 DOI: 10.1021/acs.jproteome.0c00290] [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: 12/26/2022]
Abstract
Cryptic peptides (cryptides) are biologically active peptides formed after proteolysis of native precursors present in animal venoms, for example. Proteolysis is an overlooked post-translational modification that increases venom complexity. The tripeptide KPP (Lys-Pro-Pro) is a peptide encrypted in the C-terminus of Ts14-a 25-mer peptide from the venom of the Tityus serrulatus scorpion that has a positive impact on the cardiovascular system, inducing vasodilation and reducing arterial blood pressure of hypertensive rats among other beneficial effects. A previous study reported that KPP and its native peptide Ts14 act via activation of the bradykinin receptor B2 (B2R). However, the cellular events underlying the activation of B2R by KPP are unknown. To study the cell signaling triggered by the Ts14 cryptide KPP, we incubated cardiac myocytes isolated from C57BL/6 mice with KPP (10-7 mol·L-1) for 0, 5, or 30 min and explored the proteome and phosphoproteome. Our results showed that KPP regulated cardiomyocyte proteins associated with, but not limited to, apoptosis, muscle contraction, protein turnover, and the respiratory chain. We also reported that KPP led to AKT phosphorylation, activating AKT and its downstream target nitric oxide synthase. We also observed that KPP led to dephosphorylation of phospholamban (PLN) at its activation sites (S16 and T17), leading to reduced contractility of treated cardiomyocytes. Some cellular targets reported here for KPP (e.g., AKT, PLN, and ERK) have already been reported to protect the cardiac tissue from hypoxia-induced injury. Hence, this study suggests potential beneficial effects of this scorpion cryptide that needs to be further investigated, for example, as a drug lead for cardiac infarction.
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Affiliation(s)
- Diana P Goméz-Mendoza
- Departamento de Fisiologia e Biofisica, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Rafael Pereira Lemos
- Departamento de Fisiologia e Biofisica, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Itamar C G Jesus
- Departamento de Fisiologia e Biofisica, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Vladimir Gorshkov
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense 5230, Denmark
| | - Shaun M K McKinnie
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - John C Vederas
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Frank Kjeldsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense 5230, Denmark
| | - Silvia Guatimosim
- Departamento de Fisiologia e Biofisica, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Robson Augusto Santos
- Departamento de Fisiologia e Biofisica, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Adriano M C Pimenta
- Departamento de Bioquimica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Thiago Verano-Braga
- Departamento de Fisiologia e Biofisica, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
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11
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Marins FR, Limborço-Filho M, D'Abreu BF, Machado de Almeida PW, Gavioli M, Xavier CH, Oppenheimer SM, Guatimosim S, Fontes MAP. Autonomic and cardiovascular consequences resulting from experimental hemorrhagic stroke in the left or right intermediate insular cortex in rats. Auton Neurosci 2020; 227:102695. [PMID: 32629215 DOI: 10.1016/j.autneu.2020.102695] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/20/2020] [Accepted: 06/21/2020] [Indexed: 11/17/2022]
Abstract
Damage to the insular cortex (IC) results in serious cardiovascular consequences and evidence indicates that the characteristics are lateralized. However, a study comparing the effects of focal experimental hemorrhage between IC sides was never performed. We compared the cardiovascular, autonomic and cardiac changes produced by focal experimental hemorrhage (ICH) into the left (L) or right (R) IC. Wistar rats were submitted to microinjection of autologous blood (ICH) or saline (n = 6 each side/group) into the R or L IC. Blood pressure (BP), heart rate (HR) and renal sympathetic activity (RSNA) were recorded. Measurements of calcium transient and sarcoplasmic Ca2+ ATPase expression in cardiomyocytes were performed. ICH increased baseline HR (Δ:L-ICH 452 ± 13 vs saline 407 ± 11 bpm; R-ICH 450 ± 7 vs saline 406 ± 8 bpm, P < 0.05) without changing BP. HR was restored to baseline levels after i.v. atenolol. Strikingly, ICH rats presented a reduced baseline RSNA (Δ:L-ICH 122 ± 4 vs saline 148 ± 11 spikes/s; R-ICH 112 ± 5 vs saline 148 ± 7 spikes/s, P < 0.05). After 24 h of ICH we observed a marked increase in cardiac ectopies and this number was greater after ICH R-IC. Heart weight, calcium amplitude and SERCA expression were reduced only in ICH R-IC. Focal stroke into IC can alter the cardiac and renal autonomic control. Damage to the R-IC produces a greater number of arrhythmias and changes in calcium dynamics in cardiac cells indicating that the cardiovascular consequences are hemisphere-dependent. These findings confirm asymmetry for cardiac autonomic control at the IC and help to understand the cardiac and renal implications observed after specific side cortical damage.
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Affiliation(s)
- Fernanda Ribeiro Marins
- Departamento de Fisiologia & Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marcelo Limborço-Filho
- Departamento de Fisiologia & Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Bárbara Flecha D'Abreu
- Departamento de Fisiologia & Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Pedro W Machado de Almeida
- Departamento de Fisiologia & Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mariana Gavioli
- Departamento de Fisiologia & Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Carlos Henrique Xavier
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
| | - Stephen M Oppenheimer
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Silvia Guatimosim
- Departamento de Fisiologia & Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marco Antônio Peliky Fontes
- Departamento de Fisiologia & Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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12
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Parreira RC, Gómez-Mendoza DP, de Jesus ICG, Lemos RP, Santos AK, Rezende CP, Figueiredo HCP, Pinto MCX, Kjeldsen F, Guatimosim S, Resende RR, Verano-Braga T. Cardiomyocyte Proteome Remodeling due to Isoproterenol-Induced Cardiac Hypertrophy during the Compensated Phase. Proteomics Clin Appl 2020; 14:e2000017. [PMID: 32506788 DOI: 10.1002/prca.202000017] [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: 02/18/2020] [Revised: 04/29/2020] [Indexed: 11/09/2022]
Abstract
PURPOSE Although the pathophysiological response of cardiac tissue to pro-hypertrophic stimulus is well characterized, a comprehensive characterization of the molecular events underlying the pathological hypertrophy in cardiomyocytes during the early compensated cardiac hypertrophy is currently lacking. EXPERIMENTAL DESIGN A quantitative label-free proteomic analysis of cardiomyocytes isolated was conducted from mice treated subcutaneously with isoproterenol (ISO) during 7 days in comparison with cardiomyocytes from control animals (CT). RESULTS Canonical pathway analysis of dysregulated proteins indicated that ISO-hypertrophy drives the activation of actin cytoskeleton and integrin-linked kinase (ILK) signaling, and inhibition of the sirtuin signaling. Alteration in cardiac contractile function and calcium signaling are predicted as downstream effects of ISO-hypertrophy probably due to the upregulation of key elements such as myosin-7 (MYH7). Confocal microscopy corroborated that indeed ISO-treatment led to increased abundance of MYH7. Potential early markers for cardiac hypertrophy as APBB1, GOLGA4, HOOK1, KATNA1, KIFBP, MAN2B2, and SLC16A1 are also reported. CONCLUSIONS AND CLINICAL RELEVANCE The data consist in a complete molecular mapping of ISO-induced compensated cardiac hypertrophy model at cardiomyocyte level. Marker candidates reported may assist early diagnosis of cardiac hypertrophy and ultimately heart failure.
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Affiliation(s)
- Ricardo Cambraia Parreira
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil.,Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil.,Centro Universitário de Mineiros, UNIFIMES, Trindade, Golás, 75380-307, Brazil
| | - Diana Paola Gómez-Mendoza
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Itamar Couto Guedes de Jesus
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Rafael Pereira Lemos
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Anderson Kennedy Santos
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil.,Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Cristiana Perdigão Rezende
- Departamento de Medicina Veterinária Preventiva, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Henrique César Pereira Figueiredo
- Departamento de Medicina Veterinária Preventiva, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Mauro Cunha Xavier Pinto
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Golás, 74968-755, Brazil
| | - Frank Kjeldsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, 5230, Denmark
| | - Silvia Guatimosim
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Rodrigo Ribeiro Resende
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Thiago Verano-Braga
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
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13
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Malécot CO. Low voltage-activated channels in rat pulmonary vein cardiomyocytes: coexistence of a non-selective cationic channel and of T-type Ca channels. Pflugers Arch 2020; 472:1019-1029. [PMID: 32556635 DOI: 10.1007/s00424-020-02413-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 10/24/2022]
Abstract
In rat pulmonary vein (PV) cardiomyocytes (CM), norepinephrine (NE) induces an automatic activity consisting of bursts of slow action potentials which depend on Ca2+ (upstroke) and Na+ (inter-burst) channels. Our objective was to characterize low voltage-activated (LVA) currents in rat PVCM susceptible to trigger this activity. Whole-cell ICa (5 mM Ca2+) was recorded from - 100 mV with classical Na+- and K+-free solutions. A fast LVA ICa (FLVA-ICa), present in ≈ 56% of PVCM between ~ - 50 to - 20 mV, was blocked by 10 μM TTX and markedly increased by addition of NaCl (1 or 3 mM) or KCl (5 or 10 mM). Permeability ratios P'Ca/PNa and P'Ca/PK calculated for bi-ionic conditions were respectively 2.25 ± 0.51 and 1.88 ± 0.25, and not different from a value of 2. FLVA-ICa was increased by 10 μM NE and 300 nM BayK8644, decreased by 5 μM nifedipine but not blocked by ranolazine (10 μM). NiCl2 (40 μM) and TTA-A2 (10 or 100 nM) increased FLVA-ICa. Similar results were obtained in left atrial (LA) CM. Neither Ba2+ nor Sr2+ alone could permeate the FLVA channel or block Ca2+ influx but revealed a large slower activating and inactivating LVA Ca2+ current (SLVA-ICa), present in 10 out of 80 PVCM, absent in LACM, and partially inhibited by 100 nM TTA-A2. Therefore, the ionic channel underlying FLVA-ICa is likely a fast voltage-gated non-selective channel with a dihydropyridine binding site. SLVA-ICa might correspond to Ca2+ influx through Cav3.x channels and contribute to triggering NE-induced automatic activity in the PV myocardial sleeve.
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Affiliation(s)
- Claire O Malécot
- Centre National de la Recherche Scientifique and Laboratoire Signalisation et Transports Ioniques Membranaires EA 7349, Université de Tours, Université de Poitiers, Parc de Grandmont, 37200, Tours, France.
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14
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Hanemaaijer NA, Popovic MA, Wilders X, Grasman S, Pavón Arocas O, Kole MH. Ca 2+ entry through Na V channels generates submillisecond axonal Ca 2+ signaling. eLife 2020; 9:54566. [PMID: 32553116 PMCID: PMC7380941 DOI: 10.7554/elife.54566] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 06/12/2020] [Indexed: 12/15/2022] Open
Abstract
Calcium ions (Ca2+) are essential for many cellular signaling mechanisms and enter the cytosol mostly through voltage-gated calcium channels. Here, using high-speed Ca2+ imaging up to 20 kHz in the rat layer five pyramidal neuron axon we found that activity-dependent intracellular calcium concentration ([Ca2+]i) in the axonal initial segment was only partially dependent on voltage-gated calcium channels. Instead, [Ca2+]i changes were sensitive to the specific voltage-gated sodium (NaV) channel blocker tetrodotoxin. Consistent with the conjecture that Ca2+ enters through the NaV channel pore, the optically resolved ICa in the axon initial segment overlapped with the activation kinetics of NaV channels and heterologous expression of NaV1.2 in HEK-293 cells revealed a tetrodotoxin-sensitive [Ca2+]i rise. Finally, computational simulations predicted that axonal [Ca2+]i transients reflect a 0.4% Ca2+ conductivity of NaV channels. The findings indicate that Ca2+ permeation through NaV channels provides a submillisecond rapid entry route in NaV-enriched domains of mammalian axons. Nerve cells communicate using tiny electrical impulses called action potentials. Special proteins termed ion channels produce these electric signals by allowing specific charged particles, or ions, to pass in or out of cells across its membrane. When a nerve cell ‘fires’ an action potential, specific ion channels briefly open to let in a surge of positively charged ions which electrify the cell. Action potentials begin in the same place in each nerve cell, at an area called the axon initial segment. The large number of sodium channels at this site kick-start the influx of positively charged sodium ions ensuring that every action potential starts from the same place. Previous research has shown that, when action potentials begin, the concentration of calcium ions at the axon initial segment also increases, but it was not clear which ion channels were responsible for this entry of calcium. Channels that are selective for calcium ions are the prime candidates for this process. However, research in squid nerve cells gave rise to an unexpected idea by suggesting that sodium channels may not exclusively let in sodium but also allow some calcium ions to pass through. Hanemaaijer, Popovic et al. therefore wanted to test the routes that calcium ions take and see whether the sodium channels in mammalian nerve cells are also permeable to calcium. Experiments using fluorescent dyes to track the concentration of calcium in rat and human nerve cells showed that calcium ions accumulated at the axon initial segment when action potentials fired. Most of this increase in calcium could be stopped by treating the neurons with a toxin that prevents sodium channels from opening. Electrical manipulations of the cells revealed that, in this context, the calcium ions were effectively behaving like sodium ions. Human kidney cells were then engineered to produce the sodium channel protein. This confirmed that calcium and sodium ions were indeed both passing through the same channel. These results shed new light on the relationship between calcium ions and sodium channels within the mammalian nervous system and that this interplay occurs at the axon initial segment of the cell. Genetic mutations that ‘nudge’ sodium channels towards favoring calcium entry are also found in patients with autism spectrum disorders, and so this new finding may contribute to our understanding of these conditions.
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Affiliation(s)
- Naomi Ak Hanemaaijer
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands.,Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Marko A Popovic
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands
| | - Xante Wilders
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands
| | - Sara Grasman
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands
| | - Oriol Pavón Arocas
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands
| | - Maarten Hp Kole
- Department of Axonal Signaling, Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands.,Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
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15
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Redox-Active Drug, MnTE-2-PyP 5+, Prevents and Treats Cardiac Arrhythmias Preserving Heart Contractile Function. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:4850697. [PMID: 32273944 PMCID: PMC7115175 DOI: 10.1155/2020/4850697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 01/11/2020] [Indexed: 01/06/2023]
Abstract
Background Cardiomyopathies remain among the leading causes of death worldwide, despite all efforts and important advances in the development of cardiovascular therapeutics, demonstrating the need for new solutions. Herein, we describe the effects of the redox-active therapeutic Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, AEOL10113, BMX-010 (MnTE-2-PyP5+), on rat heart as an entry to new strategies to circumvent cardiomyopathies. Methods Wistar rats weighing 250-300 g were used in both in vitro and in vivo experiments, to analyze intracellular Ca2+ dynamics, L-type Ca2+ currents, Ca2+ spark frequency, intracellular reactive oxygen species (ROS) levels, and cardiomyocyte and cardiac contractility, in control and MnTE-2-PyP5+-treated cells, hearts, or animals. Cells and hearts were treated with 20 μM MnTE-2-PyP5+ and animals with 1 mg/kg, i.p. daily. Additionally, we performed electrocardiographic and echocardiographic analysis. Results Using isolated rat cardiomyocytes, we observed that MnTE-2-PyP5+ reduced intracellular Ca2+ transient amplitude, without altering cell contractility. Whereas MnTE-2-PyP5+ did not alter basal ROS levels, it was efficient in modulating cardiomyocyte redox state under stress conditions; MnTE-2-PyP5+ reduced Ca2+ spark frequency and increased sarcoplasmic reticulum (SR) Ca2+ load. Accordingly, analysis of isolated perfused rat hearts showed that MnTE-2-PyP5+ preserves cardiac function, increases SR Ca2+ load, and reduces arrhythmia index, indicating an antiarrhythmic effect. In vivo experiments showed that MnTE-2-PyP5+ treatment increased Ca2+ transient, preserved cardiac ejection fraction, and reduced arrhythmia index and duration. MnTE-2-PyP5+ was effective both to prevent and to treat cardiac arrhythmias. Conclusion MnTE-2-PyP5+ prevents and treats cardiac arrhythmias in rats. In contrast to most antiarrhythmic drugs, MnTE-2-PyP5+ preserves cardiac contractile function, arising, thus, as a prospective therapeutic for improvement of cardiac arrhythmia treatment.
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16
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Lin X, Barravecchia M, Matthew Kottmann R, Sime P, Dean DA. Caveolin-1 gene therapy inhibits inflammasome activation to protect from bleomycin-induced pulmonary fibrosis. Sci Rep 2019; 9:19643. [PMID: 31873099 PMCID: PMC6928213 DOI: 10.1038/s41598-019-55819-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 11/30/2019] [Indexed: 01/04/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a devastating and fatal disease and characterized by increased deposition of extracellular matrix proteins and scar formation in the lung, resulting from alveolar epithelial damage and accumulation of inflammatory cells. Evidence suggests that Caveolin-1 (Cav-1), a major component of caveolae which regulates cell signaling and endocytosis, is a potential target to treat fibrotic diseases, although the mechanisms and responsible cell types are unclear. We show that Cav-1 expression was downregulated both in alveolar epithelial type I cells in bleomycin-injured mouse lungs and in lung sections from IPF patients. Increased expression of IL-1β and caspase-1 has been observed in IPF patients, indicating inflammasome activation associated with IPF. Gene transfer of a plasmid expressing Cav-1 using transthoracic electroporation reduced infiltration of neutrophils and monocytes/macrophages and protected from subsequent bleomycin-induced pulmonary fibrosis. Overexpression of Cav-1 suppressed bleomycin- or silica-induced activation of caspase-1 and maturation of pro-IL-1β to secrete cleaved IL-1β both in mouse lungs and in primary type I cells. These results demonstrate that gene transfer of Cav-1 downregulates inflammasome activity and protects from subsequent bleomycin-mediated pulmonary fibrosis. This indicates a pivotal regulation of Cav-1 in inflammasome activity and suggests a novel therapeutic strategy for patients with IPF.
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Affiliation(s)
- Xin Lin
- Department of Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
| | - Michael Barravecchia
- Department of Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
| | - R Matthew Kottmann
- Department of Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
| | - Patricia Sime
- Department of Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
| | - David A Dean
- Department of Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA.
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17
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Rodrigues-Ribeiro L, Melo-Braga MN, Kjeldsen F, Gómez-Mendoza DP, Verano-Braga T. Assessment of protein extraction and digestion efficiency of well-established shotgun protocols for heart proteomics. Anal Biochem 2019; 578:51-59. [DOI: 10.1016/j.ab.2019.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/08/2019] [Accepted: 05/08/2019] [Indexed: 12/18/2022]
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18
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Encapsulation of Mesenchymal Stem Cells in 3D Ovarian Cell Constructs Promotes Stable and Long-Term Hormone Secretion with Improved Physiological Outcomes in a Syngeneic Rat Model. Ann Biomed Eng 2019; 48:1058-1070. [PMID: 31367915 DOI: 10.1007/s10439-019-02334-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/24/2019] [Indexed: 02/06/2023]
Abstract
Loss of ovarian function (e.g., due to menopause) leads to profound physiological effects in women including changes in sexual function and osteoporosis. Hormone therapies are a known solution, but their use has significantly decreased due to concerns over cardiovascular disease and certain cancers. We recently reported a tissue-engineering strategy for cell hormone therapy (cHT) in which granulosa cells and theca cells are encapsulated to mimic native ovarian follicles. cHT improved physiological outcomes and safety compared to pharmacological hormone therapies in a rat ovariectomy model. However, cHT did not achieve estrogen levels as high as ovary-intact animals. In this report, we examined if hormone secretion from cHT constructs is impacted by incorporation of bone marrow-derived mesenchymal stem cells (BMSC) since these cells contain regulatory factors such as aromatase necessary for estrogen production. Incorporation of BMSCs led to enhanced estrogen secretion in vitro. Moreover, cHT constructs with BMSCs achieved estrogen secretion levels significantly greater than constructs without BMSCs in ovariectomized rats from 70 to 90 days after implantation, while also regulating pituitary hormones. cHT constructs with BMSC ameliorated estrogen deficiency-induced uterine atrophy without hyperplasia. The results indicate that inclusion of BMSC in cHT strategies can improve performance.
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19
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Wang W, Mellor RL, Nerbonne JM, Balke CW. Regional differences in the expression of tetrodotoxin-sensitive inward Ca 2+ and outward Cs +/K + currents in mouse and human ventricles. Channels (Austin) 2019; 13:72-87. [PMID: 30704344 PMCID: PMC6380286 DOI: 10.1080/19336950.2019.1568146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Tetrodotoxin (TTX) sensitive inward Ca2+ currents, ICa(TTX), have been identified in cardiac myocytes from several species, although it is unclear if ICa(TTX) is expressed in all cardiac cell types, and if ICa(TTX) reflects Ca2+ entry through the main, Nav1.5-encoded, cardiac Na+ (Nav) channels. To address these questions, recordings were obtained with 2 mm Ca2+ and 0 mm Na+ in the bath and 120 mm Cs+ in the pipettes from myocytes isolated from adult mouse interventricular septum (IVS), left ventricular (LV) endocardium, apex, and epicardium and from human LV endocardium and epicardium. On membrane depolarizations from a holding potential of −100 mV, ICa(TTX) was identified in mouse IVS and LV endocardial myocytes and in human LV endocardial myocytes, whereas only TTX-sensitive outward Cs+/K+ currents were observed in mouse LV apex and epicardial myocytes and human LV epicardial myocytes. The inward Ca2+, but not the outward Cs+/K+, currents were blocked by mm concentrations of MTSEA, a selective blocker of cardiac Nav1.5-encoded Na+ channels. In addition, in Nav1.5-expressing tsA-201 cells, ICa(TTX) was observed in 3 (of 20) cells, and TTX-sensitive outward Cs+/K+ currents were observed in the other (17) cells. The time- and voltage-dependent properties of the TTX-sensitive inward Ca2+ and outward Cs+/K+ currents recorded in Nav1.5-expressing tsA-201 were indistinguishable from native currents in mouse and human cardiac myocytes. Overall, the results presented here suggest marked regional, cell type-specific, differences in the relative ion selectivity, and likely the molecular architecture, of native SCN5A-/Scn5a- (Nav1.5-) encoded cardiac Na+ channels in mouse and human ventricles.
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Affiliation(s)
- Wei Wang
- a Center for Cardiovascular Research, Department of Medicine, Cardiovascular Division , Washington University School of Medicine , St. Louis , MO , USA
| | - Rebecca L Mellor
- a Center for Cardiovascular Research, Department of Medicine, Cardiovascular Division , Washington University School of Medicine , St. Louis , MO , USA
| | - Jeanne M Nerbonne
- a Center for Cardiovascular Research, Department of Medicine, Cardiovascular Division , Washington University School of Medicine , St. Louis , MO , USA.,b John Cochran Veterans Administration Medical Center , St. Louis , MO , USA
| | - C William Balke
- a Center for Cardiovascular Research, Department of Medicine, Cardiovascular Division , Washington University School of Medicine , St. Louis , MO , USA.,b John Cochran Veterans Administration Medical Center , St. Louis , MO , USA
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Jesus ICGD, Scalzo S, Alves F, Marques K, Rocha-Resende C, Bader M, Santos RAS, Guatimosim S. Alamandine acts via MrgD to induce AMPK/NO activation against ANG II hypertrophy in cardiomyocytes. Am J Physiol Cell Physiol 2018; 314:C702-C711. [PMID: 29443552 DOI: 10.1152/ajpcell.00153.2017] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The renin-angiotensin system (RAS) plays a pivotal role in the pathogenesis of cardiovascular diseases. New members of this system have been characterized and shown to have biologically relevant actions. Alamandine and its receptor MrgD are recently identified components of RAS. In the cardiovascular system, alamandine actions included vasodilation, antihypertensive, and antifibrosis effects. Currently, the actions of alamandine on cardiomyocytes are unknown. Here our goal was twofold: 1) to unravel the signaling molecules activated by the alamandine/MrgD axis in cardiomyocytes; and 2) to evaluate the ability of this axis to prevent angiotensin II (ANG II)-induced hypertrophy. In cardiomyocytes from C57BL/6 mice, alamandine treatment induced an increase in nitric oxide (NO) production, which was blocked by d-Pro7-ANG-(1-7), a MrgD antagonist. This NO rise correlated with increased phosphorylation of AMPK. Alamandine-induced NO production was preserved in Mas-/- myocytes and lost in MrgD-/- cells. Binding of fluorescent-labeled alamandine was observed in wild-type cells, but it was dramatically reduced in MrgD-/- myocytes. We also assessed the consequences of prolonged alamandine exposure to cultured neonatal rat cardiomyocytes (NRCMs) treated with ANG II. Treatment of NRCMs with alamandine prevented ANG II-induced hypertrophy. Moreover, the antihypertrophic actions of alamandine were mediated via MrgD and NO, since they could be prevented by d-Pro7-ANG-(1-7) or inhibitors of NO synthase or AMPK. β-Alanine, a MrgD agonist, recapitulated alamandine's cardioprotective effects in cardiomyocytes. Our data show that alamandine via MrgD induces AMPK/NO signaling to counterregulate ANG II-induced hypertrophy. These findings highlight the therapeutic potential of the alamandine/MrgD axis in the heart.
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Affiliation(s)
- Itamar Couto Guedes de Jesus
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.,National Institute of Science and Technology in Nanobiopharmaceutics , Belo Horizonte , Brazil
| | - Sérgio Scalzo
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais , Belo Horizonte , Brazil
| | - Fabiana Alves
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais , Belo Horizonte , Brazil
| | - Kariny Marques
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais , Belo Horizonte , Brazil
| | - Cibele Rocha-Resende
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais , Belo Horizonte , Brazil
| | - Michael Bader
- Max Delbrück Center for Molecular Medicine , Berlin , Germany
| | - Robson A Souza Santos
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.,National Institute of Science and Technology in Nanobiopharmaceutics , Belo Horizonte , Brazil
| | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.,National Institute of Science and Technology in Nanobiopharmaceutics , Belo Horizonte , Brazil
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21
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Camargo-Silva G, Turones LC, da Cruz KR, Gomes KP, Mendonça MM, Nunes A, de Jesus IG, Colugnati DB, Pansani AP, Pobbe RLH, Santos R, Fontes MAP, Guatimosim S, de Castro CH, Ianzer D, Ferreira RN, Xavier CH. Ghrelin potentiates cardiac reactivity to stress by modulating sympathetic control and beta-adrenergic response. Life Sci 2018; 196:84-92. [PMID: 29366747 DOI: 10.1016/j.lfs.2018.01.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/10/2018] [Accepted: 01/18/2018] [Indexed: 02/07/2023]
Abstract
Prior evidence indicates that ghrelin is involved in the integration of cardiovascular functions and behavioral responses. Ghrelin actions are mediated by the growth hormone secretagogue receptor subtype 1a (GHS-R1a), which is expressed in peripheral tissues and central areas involved in the control of cardiovascular responses to stress. AIMS In the present study, we assessed the role of ghrelin - GHS-R1a axis in the cardiovascular reactivity to acute emotional stress in rats. MAIN METHODS AND KEY FINDINGS Ghrelin potentiated the tachycardia evoked by restraint and air jet stresses, which was reverted by GHS-R1a blockade. Evaluation of the autonomic balance revealed that the sympathetic branch modulates the ghrelin-evoked positive chronotropy. In isolated hearts, the perfusion with ghrelin potentiated the contractile responses caused by stimulation of the beta-adrenergic receptor, without altering the amplitude of the responses evoked by acetylcholine. Experiments in isolated cardiomyocytes revealed that ghrelin amplified the increases in calcium transient changes evoked by isoproterenol. SIGNIFICANCE Taken together, our results indicate that the Ghrelin-GHS-R1a axis potentiates the magnitude of stress-evoked tachycardia by modulating the autonomic nervous system and peripheral mechanisms, strongly relying on the activation of cardiac calcium transient and beta-adrenergic receptors.
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Affiliation(s)
- Gabriel Camargo-Silva
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Larissa Córdova Turones
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Kellen Rosa da Cruz
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Karina Pereira Gomes
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Michelle Mendanha Mendonça
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Allancer Nunes
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Itamar Guedes de Jesus
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Diego Basile Colugnati
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Aline Priscila Pansani
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Roger Luis Henschel Pobbe
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Robson Santos
- National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil
| | | | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil
| | - Carlos Henrique de Castro
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil; National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil
| | - Danielle Ianzer
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil; National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil
| | - Reginaldo Nassar Ferreira
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Carlos Henrique Xavier
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil; National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil.
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22
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Rocha-Resende C, Guedes de Jesus IC, Roman-Campos D, Miranda AS, Alves F, Resende RR, Dos Santos Cruz J, Machado FS, Guatimosim S. Absence of suppressor of cytokine signaling 2 turns cardiomyocytes unresponsive to LIF-dependent increases in Ca 2+ levels. Am J Physiol Cell Physiol 2017; 312:C478-C486. [PMID: 28122728 DOI: 10.1152/ajpcell.00004.2016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 01/12/2023]
Abstract
Little is known regarding the role of suppressor of cytokine signaling (SOCS) in the control of cytokine signaling in cardiomyocytes. We investigated the consequences of SOCS2 ablation for leukemia inhibitory factor (LIF)-induced enhancement of intracellular Ca2+ ([Ca2+]i) transient by performing experiments with cardiomyocytes from SOCS2-knockout (ko) mice. Similar levels of SOCS3 transcripts were seen in cardiomyocytes from wild-type and SOCS2-ko mice, while SOCS1 mRNA was reduced in SOCS2-ko. Immunoprecipitation experiments showed increased SOCS3 association with gp130 receptor in SOCS2-ko myocytes. Measurements of Ca2+ in wild-type myocytes exposed to LIF showed a significant increase in the magnitude of the Ca2+ transient. This change was absent in LIF-treated SOCS2-ko cells. LIF activation of ERK and STAT3 was observed in both wild-type and SOCS2-ko cells, indicating that in SOCS2-ko, LIF receptors were functional, despite the lack of effect in the Ca2+ transient. In wild-type cells, LIF-induced increase in [Ca2+]i and phospholamban Thr17 [PLN(Thr17)] phosphorylation was inhibited by KN-93, indicating a role for CaMKII in LIF-induced Ca2+ raise. LIF-induced phosphorylation of PLN(Thr17) was abrogated in SOCS2-ko myocytes. In wild-type cardiomyocytes, LIF treatment increased L-type Ca2+ current (ICa,L), a key activator of CaMKII in response to LIF. Conversely, SOCS2-ko myocytes failed to activate ICa,L in response to LIF, providing a rationale for the lack of LIF effect on Ca2+ transient. Our data show that absence of SOCS2 turns cardiomyocytes unresponsive to LIF-induced [Ca2+] raise, indicating that endogenous levels of SOCS2 are crucial for full activation of LIF signaling in the heart.
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Affiliation(s)
- Cibele Rocha-Resende
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Itamar Couto Guedes de Jesus
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Danilo Roman-Campos
- Department of Biophysics, Paulista School of Medicine, Universidade Federal de São Paulo, Sao Paulo, Brazil
| | - Artur S Miranda
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; and
| | - Fabiana Alves
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Rodrigo Ribeiro Resende
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; and
| | - Jader Dos Santos Cruz
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; and
| | - Fabiana Simão Machado
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; and
| | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil;
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Bodi I, Nakayama H, Schwartz A. Tetrodotoxin-sensitive Ca2+ Currents, but No T-type Currents in Normal, Hypertrophied, and Failing Mouse Cardiomyocytes. J Cardiovasc Pharmacol 2016; 68:452-464. [PMID: 27617699 PMCID: PMC5145783 DOI: 10.1097/fjc.0000000000000432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS To obtain functional evidence that ICa,T is involved in the pathogenesis of cardiac hypertrophy and heart failure. We unexpectedly identified ICa(TTX) rather than ICa,T, therefore, we adjusted our aim to encompass these findings. METHODS AND RESULTS We investigated (1) Cav3.1 (α1G) transgenic (Tg) mice compared with nontransgenic (tTA-Ntg); (2) Cav3.1-deficient mice (Cav3.1) compared with wild type (Wt) after chemically and surgically induced cardiac remodeling; and (3) spontaneous hypertensive rats and thoracic aortic constriction (TAC) rats. Whole-cell patch-clamp technique was used to measure ICa in ventricular myocytes. Cav3.1-Tg expressed ICa,T (-18.35 ± 1.02 pA/pF at -40 mV) without signs of compromised cardiac function. While we failed to detect ICa,T after hypertrophic stimuli, instead we demonstrated that both Wt and Cav3.1 mouse exhibit ICa(TTX). Using TAC rats, only 2 of 24 VMs showed ICa,T under our experimental conditions. Without TTX, ICa(TTX) occurred in VMs from Wt, spontaneous hypertensive rats, and TAC rats also. CONCLUSIONS These findings demonstrate for the first time that mouse VMs express ICa(TTX). We suggest that future studies should take into consideration the measuring conditions when interpreting ICa,T reappearance in ventricular myocytes in response to hypertrophic stress. Contamination with ICa(TTX) could possibly confuse the relevance of the data.
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Affiliation(s)
- Ilona Bodi
- Department of Pediatrics, Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Hiroyuki Nakayama
- Department of Pediatrics, Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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Costal-Oliveira F, Guerra-Duarte C, Oliveira MS, Castro KLPD, Lopes-de-Sousa L, Lara A, Gomes ERDM, Bonilla C, Guatimosim S, Melo MM, Chávez-Olórtegui C. Cardiorespiratory alterations in rodents experimentally envenomed with Hadruroides lunatus scorpion venom. J Venom Anim Toxins Incl Trop Dis 2016; 23:2. [PMID: 27429609 PMCID: PMC4947318 DOI: 10.1186/s40409-016-0076-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 07/06/2016] [Indexed: 11/24/2022] Open
Abstract
Background Hadruroides lunatus is the most abundant scorpion species in the Peruvian central coast, where most of the accidents involving humans are registered. In spite of its prevalence, there are only very few studies on H. lunatus envenomation. The aim of the present study was to analyze the cardiorespiratory alterations caused by H. lunatus envenomation in rodents. Methods Wistar rats injected with H. lunatus scorpion venom were submitted to electrocardiography. After euthanasia, rat lungs were collected and histopathologically analyzed. Mouse cardiomyocytes were used to perform immunofluorescence and calcium transient assays. Data were analyzed by ANOVA or Student’s t-test. The significance level was set at p < 0.05. Results It was observed that H. lunatus venom increased heart rate and caused arrhythmia, thereby impairing the heart functioning. Lungs of envenomed animals showed significant alterations, such as diffuse hemorrhage. In addition, immunofluorescence showed that H. lunatus venom was capable of binding to cardiomyocytes. Furthermore, mouse ventricular cardiomyocytes incubated with H. lunatus venom showed a significant decrease in calcium transient, confirming that H. lunatus venom exerts a toxic effect on heart. Conclusion Our results showed that H. lunatus venom is capable of inducing cardiorespiratory alterations, a typical systemic effect of scorpionism, stressing the importance of medical monitoring in envenomation cases.
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Affiliation(s)
- Fernanda Costal-Oliveira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, CP: 486 CEP: 31270-901 MG Brazil
| | - Clara Guerra-Duarte
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, CP: 486 CEP: 31270-901 MG Brazil
| | - Maira Souza Oliveira
- College of Veterinary Medicine, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Karen Larissa Pereira de Castro
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, CP: 486 CEP: 31270-901 MG Brazil
| | - Leticia Lopes-de-Sousa
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, CP: 486 CEP: 31270-901 MG Brazil
| | - Aline Lara
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Enéas Ricardo de Morais Gomes
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Cesar Bonilla
- Instituto Nacional de Salud, Universidad Nacional Mayor de San Marcos y Universidad Científica del Sur, Lima, Peru
| | - Sílvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Marília Martins Melo
- College of Veterinary Medicine, Federal University of Minas Gerais, Belo Horizonte, MG Brazil
| | - Carlos Chávez-Olórtegui
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, CP: 486 CEP: 31270-901 MG Brazil
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25
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Poláková E, Illaste A, Niggli E, Sobie EA. Maximal acceleration of Ca2+ release refractoriness by β-adrenergic stimulation requires dual activation of kinases PKA and CaMKII in mouse ventricular myocytes. J Physiol 2014; 593:1495-507. [PMID: 25772298 DOI: 10.1113/jphysiol.2014.278051] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 08/30/2014] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Refractoriness of calcium release in heart cells is altered in several disease states, but the physiological mechanisms that regulate this process are incompletely understood. We examined refractoriness of calcium release in mouse ventricular myocytes and investigated how activation of different intracellular signalling pathways influenced this process. We found that refractoriness of calcium release is abbreviated by stimulation of the 'fight-or-flight' response, and that simultaneous activation of multiple intracellular signalling pathways contributes to this response. Data obtained under several conditions at the subcellular, microscopic level were consistent with results obtained at the cellular level. The results provide insight into regulation of cardiac calcium release and how alterations to this process may increase arrhythmia risk under different conditions. ABSTRACT Time-dependent refractoriness of calcium (Ca(2+)) release in cardiac myocytes is an important factor in determining whether pro-arrhythmic release patterns develop. At the subcellular level of the Ca(2+) spark, recent studies have suggested that recovery of spark amplitude is controlled by local sarcoplasmic reticulum (SR) refilling whereas refractoriness of spark triggering depends on both refilling and the sensitivity of the ryanodine receptor (RyR) release channels that produce sparks. Here we studied regulation of Ca(2+) spark refractoriness in mouse ventricular myocytes by examining how β-adrenergic stimulation influenced sequences of Ca(2+) sparks originating from individual RyR clusters. Our protocol allowed us to separately measure recovery of spark amplitude and delays between successive sparks, and data were interpreted quantitatively through simulations with a stochastic mathematical model. We found that, compared with spark sequences measured under control conditions: (1) β-adrenergic stimulation with isoproterenol (isoprenaline) accelerated spark amplitude recovery and decreased spark-to-spark delays; (2) activating protein kinase A (PKA) with forskolin accelerated amplitude recovery but did not affect spark-to-spark delays; (3) inhibiting PKA with H89 retarded amplitude recovery and increased spark-to-spark delays; (4) preventing phosphorylation of the RyR at serine 2808 with a knock-in mouse prevented the decrease in spark-to-spark delays seen with β-adrenergic stimulation; (5) inhibiting either PKA or Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) during β-adrenergic stimulation prevented the decrease in spark-to-spark delays seen without inhibition. The results suggest that activation of either PKA or CaMKII is sufficient to speed SR refilling, but activation of both kinases appears necessary to observe increased RyR sensitivity. The data provide novel insight into β-adrenergic regulation of Ca(2+) release refractoriness in mouse myocytes.
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Affiliation(s)
- Eva Poláková
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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26
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Gavioli M, Lara A, Almeida PWM, Lima AM, Damasceno DD, Rocha-Resende C, Ladeira M, Resende RR, Martinelli PM, Melo MB, Brum PC, Fontes MAP, Souza Santos RA, Prado MAM, Guatimosim S. Cholinergic signaling exerts protective effects in models of sympathetic hyperactivity-induced cardiac dysfunction. PLoS One 2014; 9:e100179. [PMID: 24992197 PMCID: PMC4081111 DOI: 10.1371/journal.pone.0100179] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 05/23/2014] [Indexed: 12/17/2022] Open
Abstract
Cholinergic control of the heart is exerted by two distinct branches; the autonomic component represented by the parasympathetic nervous system, and the recently described non-neuronal cardiomyocyte cholinergic machinery. Previous evidence has shown that reduced cholinergic function leads to deleterious effects on the myocardium. Yet, whether conditions of increased cholinergic signaling can offset the pathological remodeling induced by sympathetic hyperactivity, and its consequences for these two cholinergic axes are unknown. Here, we investigated two models of sympathetic hyperactivity: i) the chronic beta-adrenergic receptor stimulation evoked by isoproterenol (ISO), and ii) the α2A/α2C-adrenergic receptor knockout (KO) mice that lack pre-synaptic adrenergic receptors. In both models, cholinergic signaling was increased by administration of the cholinesterase inhibitor, pyridostigmine. First, we observed that isoproterenol produces an autonomic imbalance characterized by increased sympathetic and reduced parasympathetic tone. Under this condition transcripts for cholinergic proteins were upregulated in ventricular myocytes, indicating that non-neuronal cholinergic machinery is activated during adrenergic overdrive. Pyridostigmine treatment prevented the effects of ISO on autonomic function and on the ventricular cholinergic machinery, and inhibited cardiac remodeling. α2A/α2C-KO mice presented reduced ventricular contraction when compared to wild-type mice, and this dysfunction was also reversed by cholinesterase inhibition. Thus, the cardiac parasympathetic system and non-neuronal cardiomyocyte cholinergic machinery are modulated in opposite directions under conditions of increased sympathetic drive or ACh availability. Moreover, our data support the idea that pyridostigmine by restoring ACh availability is beneficial in heart disease.
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Affiliation(s)
- Mariana Gavioli
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Aline Lara
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Pedro W. M. Almeida
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Augusto Martins Lima
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- National Institute of Science and Technology in Nanobiopharmaceutics, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Denis D. Damasceno
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Cibele Rocha-Resende
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marina Ladeira
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Rodrigo R. Resende
- Department of Biochemistry, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Patricia M. Martinelli
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marcos Barrouin Melo
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- National Institute of Science and Technology in Nanobiopharmaceutics, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Patricia C. Brum
- School of Physical Education and Sport, Universidade de São Paulo, São Paulo, Brazil
| | - Marco Antonio Peliky Fontes
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- National Institute of Science and Technology in Nanobiopharmaceutics, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Robson A. Souza Santos
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- National Institute of Science and Technology in Nanobiopharmaceutics, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Marco A. M. Prado
- Robarts Research Institute, University of Western Ontario, Department of Physiology and Pharmacology, Department of Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada
| | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- National Institute of Science and Technology in Nanobiopharmaceutics, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
- * E-mail:
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Melo DS, Riul TR, Esteves EA, Moraes PL, Ferreira FO, Gavioli M, Alves MNM, Almeida PWM, Guatimosim S, Ferreira AJ, Dias Peixoto MF. Effects of severe caloric restriction from birth on the hearts of adult rats. Appl Physiol Nutr Metab 2013; 38:879-85. [DOI: 10.1139/apnm-2012-0387] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
There has been increasing evidence suggesting that a severe caloric restriction (SCR) (above 40%) has beneficial effects on the hearts of rats. However, most of the reports have focused on the effects of SCR that started in adulthood. We investigated the consequences of SCR on the hearts of rats subjected to SCR since birth (CR50). From birth to the age of 3 months, CR50 rats were fed 50% of the food that the ad libitum group (AL) was fed. Thereafter, a maximal aerobic test was performed to indirectly evaluate global cardiovascular function. Indices of contractility (+dT/dt) and relaxation (−dT/dt) were analyzed in isolated heart preparation, and cardiomyocyte diameter, number, density, and myocardium collagen content were obtained through histologic analysis. Ventricular myocytes were isolated, using standard methods to evaluate phosphorylated AKT levels, and Ca2+ handling was evaluated with a combination of Western blot analysis, intracellular Ca2+ imaging, and confocal microscopy. CR50 rats exhibited increased aerobic performance and cardiac function, as shown by the increase in ±dT/dt. Despite the smaller cardiomyocyte diameter, CR50 rats had an increased heart−body weight ratio, increased cardiomyocyte density and number, and similar levels of myocardium collagen content, compared with AL rats. AKT was hyperphosphorylated in cardiomyocytes from CR50 rats, and there were no significant differences in Ca2+ transient and SERCA2 levels in cardiomyocytes between CR50 and AL rats. Collectively, these observations reveal the beneficial effects of a 50% caloric restriction on the hearts of adult rats restricted since birth, which might involve cardiomyocyte AKT signaling.
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Affiliation(s)
- Dirceu Sousa Melo
- Department of Biological Sciences, Federal University of Jequitinhonha and Mucuri Valleys, Diamantina, MG, Brazil
| | - Tania Regina Riul
- Department of Nutrition, Federal University of Jequitinhonha and Mucuri Valleys, Diamantina, MG, Brazil
| | - Elizabeth Adriana Esteves
- Department of Nutrition, Federal University of Jequitinhonha and Mucuri Valleys, Diamantina, MG, Brazil
| | - Patrícia Lanza Moraes
- Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Fernanda Oliveira Ferreira
- Department of Basic Sciences, Federal University of Jequitinhonha and Mucuri Valleys, Diamantina, MG, Brazil
| | - Mariana Gavioli
- Department Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | | | | | - Silvia Guatimosim
- Department Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Anderson José Ferreira
- Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Marco Fabricio Dias Peixoto
- Department of Physical Education, Federal University of Jequitinhonha and Mucuri Valleys, Diamantina, MG, Brazil
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Vanzelli AS, Medeiros A, Rolim N, Bartholomeu JB, Cunha TF, Bechara LG, Gomes ERM, Mattos KC, Sirvente R, Salemi V, Mady C, Negrao CE, Guatimosim S, Brum PC. Integrative effect of carvedilol and aerobic exercise training therapies on improving cardiac contractility and remodeling in heart failure mice. PLoS One 2013; 8:e62452. [PMID: 23658728 PMCID: PMC3641040 DOI: 10.1371/journal.pone.0062452] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 03/21/2013] [Indexed: 11/19/2022] Open
Abstract
The use of β-blockers is mandatory for counteracting heart failure (HF)-induced chronic sympathetic hyperactivity, cardiac dysfunction and remodeling. Importantly, aerobic exercise training, an efficient nonpharmacological therapy to HF, also counteracts sympathetic hyperactivity in HF and improves exercise tolerance and cardiac contractility; the latter associated with changes in cardiac Ca2+ handling. This study was undertaken to test whether combined β–blocker and aerobic exercise training would integrate the beneficial effects of isolated therapies on cardiac structure, contractility and cardiomyocyte Ca2+ handling in a genetic model of sympathetic hyperactivity-induced HF (α2A/α2C- adrenergic receptor knockout mice, KO). We used a cohort of 5–7 mo male wild-type (WT) and congenic mice (KO) with C57Bl6/J genetic background randomly assigned into 5 groups: control (WT), saline-treated KO (KOS), exercise trained KO (KOT), carvedilol-treated KO (KOC) and, combined carvedilol-treated and exercise-trained KO (KOCT). Isolated and combined therapies reduced mortality compared with KOS mice. Both KOT and KOCT groups had increased exercise tolerance, while groups receiving carvedilol had increased left ventricular fractional shortening and reduced cardiac collagen volume fraction compared with KOS group. Cellular data confirmed that cardiomyocytes from KOS mice displayed abnormal Ca2+ handling. KOT group had increased intracellular peak of Ca2+ transient and reduced diastolic Ca2+ decay compared with KOS group, while KOC had increased Ca2+ decay compared with KOS group. Notably, combined therapies re-established cardiomyocyte Ca2+ transient paralleled by increased SERCA2 expression and SERCA2:PLN ratio toward WT levels. Aerobic exercise trained increased the phosphorylation of PLN at Ser16 and Thr17 residues in both KOT and KOCT groups, but carvedilol treatment reduced lipid peroxidation in KOC and KOCT groups compared with KOS group. The present findings provide evidence that the combination of carvedilol and aerobic exercise training therapies lead to a better integrative outcome than carvedilol or exercise training used in isolation.
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Affiliation(s)
- Andréa S. Vanzelli
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | | | - Natale Rolim
- Department of Circulation and Medical Imaging and K.G. Jebsen Center of Exercise in Medicine, Trondheim, Norway
| | - Jan B. Bartholomeu
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Telma F. Cunha
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Luiz G. Bechara
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Enéas R. M. Gomes
- Physiology and Biophysics Department, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Katt C. Mattos
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Raquel Sirvente
- Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil
| | - Vera Salemi
- Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil
| | - Charles Mady
- Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil
| | - Carlos E. Negrao
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
- Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil
| | - Silvia Guatimosim
- Physiology and Biophysics Department, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Patricia C. Brum
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
- * E-mail:
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29
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Roy A, Lara A, Guimarães D, Pires R, Gomes ER, Carter DE, Gomez MV, Guatimosim S, Prado VF, Prado MAM, Gros R. An analysis of the myocardial transcriptome in a mouse model of cardiac dysfunction with decreased cholinergic neurotransmission. PLoS One 2012; 7:e39997. [PMID: 22768193 PMCID: PMC3386908 DOI: 10.1371/journal.pone.0039997] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 06/02/2012] [Indexed: 01/02/2023] Open
Abstract
Autonomic dysfunction is observed in many cardiovascular diseases and contributes to cardiac remodeling and heart disease. We previously reported that a decrease in the expression levels of the vesicular acetylcholine transporter (VAChT) in genetically-modified homozygous mice (VAChT KD(HOM)) leads to decreased cholinergic tone, autonomic imbalance and a phenotype resembling cardiac dysfunction. In order to further understand the molecular changes resulting from chronic long-term decrease in parasympathetic tone, we undertook a transcriptome-based, microarray-driven approach to analyze gene expression changes in ventricular tissue from VAChT KD(HOM) mice. We demonstrate that a decrease in cholinergic tone is associated with alterations in gene expression in mutant hearts, which might contribute to increased ROS levels observed in these cardiomyocytes. In contrast, in another model of cardiac remodeling and autonomic imbalance, induced through chronic isoproterenol treatment to increase sympathetic drive, these genes did not appear to be altered in a pattern similar to that observed in VAChT KD(HOM) hearts. These data suggest the importance of maintaining a fine balance between the two branches of the autonomic nervous system and the significance of absolute levels of cholinergic tone in proper cardiac function.
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Affiliation(s)
- Ashbeel Roy
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Departments of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Aline Lara
- Departments of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Diogo Guimarães
- Graduate Program Santa Casa, Belo Horizonte, Minas Gerais, Brazil
| | - Rita Pires
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Eneas R. Gomes
- Departments of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - David E. Carter
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Marcus V. Gomez
- Graduate Program Santa Casa, Belo Horizonte, Minas Gerais, Brazil
| | - Silvia Guatimosim
- Departments of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Vania F. Prado
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Departments of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Departments of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Marco A. M. Prado
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Departments of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Departments of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Robert Gros
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Departments of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Department of Medicine (Clinical Pharmacology), Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- * E-mail:
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Role of SOCS2 in modulating heart damage and function in a murine model of acute Chagas disease. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:130-40. [PMID: 22658486 DOI: 10.1016/j.ajpath.2012.03.042] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 02/25/2012] [Accepted: 03/07/2012] [Indexed: 01/11/2023]
Abstract
Infection with Trypanosoma cruzi induces inflammation, which limits parasite proliferation but may result in chagasic heart disease. Suppressor of cytokine signaling 2 (SOCS2) is a regulator of immune responses and may therefore participate in the pathogenesis of T. cruzi infection. SOCS2 is expressed during T. cruzi infection, and its expression is partially reduced in infected 5-lipoxygenase-deficient [knockout (KO)] mice. In SOCS2 KO mice, there was a reduction in both parasitemia and the expression of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-6, IL-10, SOCS1, and SOCS3 in the spleen. Expression of IFN-γ, TNF-α, SOCS1, and SOCS3 was also reduced in the hearts of infected SOCS2 KO mice. There was an increase in the generation and expansion of T regulatory (Treg) cells and a decrease in the number of memory cells in T. cruzi-infected SOCS2 KO mice. Levels of lipoxinA(4) (LXA(4)) increased in these mice. Echocardiography studies demonstrated an impairment of cardiac function in T. cruzi-infected SOCS2 KO mice. There were also changes in calcium handling and in action potential waveforms, and reduced outward potassium currents in isolated cardiac myocytes. Our data suggest that reductions of inflammation and parasitemia in infected SOCS2-deficient mice may be secondary to the increases in Treg cells and LXA(4) levels. This occurs at the cost of greater infection-associated heart dysfunction, highlighting the relevance of balanced inflammatory and immune responses in preventing severe T. cruzi-induced disease.
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31
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Rocha-Resende C, Roy A, Resende R, Ladeira MS, Lara A, de Morais Gomes ER, Prado VF, Gros R, Guatimosim C, Prado MAM, Guatimosim S. Non-neuronal cholinergic machinery present in cardiomyocytes offsets hypertrophic signals. J Mol Cell Cardiol 2012; 53:206-16. [PMID: 22587993 DOI: 10.1016/j.yjmcc.2012.05.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 04/17/2012] [Accepted: 05/03/2012] [Indexed: 12/19/2022]
Abstract
Recent work has provided compelling evidence that increased levels of acetylcholine (ACh) can be protective in heart failure, whereas reduced levels of ACh secretion can cause heart malfunction. Previous data show that cardiomyocytes themselves can actively secrete ACh, raising the question of whether this cardiomyocyte derived ACh may contribute to the protective effects of ACh in the heart. To address the functionality of this non-neuronal ACh machinery, we used cholinesterase inhibitors and a siRNA targeted to AChE (acetylcholinesterase) as a way to increase the availability of ACh secreted by cardiac cells. By using nitric oxide (NO) formation as a biological sensor for released ACh, we showed that cholinesterase inhibition increased NO levels in freshly isolated ventricular myocytes and that this effect was prevented by atropine, a muscarinic receptor antagonist, and by inhibition of ACh synthesis or vesicular storage. Functionally, cholinesterase inhibition prevented the hypertrophic effect as well as molecular changes and calcium transient alterations induced by adrenergic overstimulation in cardiomyocytes. Moreover, inhibition of ACh storage or atropine blunted the anti-hypertrophic action of cholinesterase inhibition. Altogether, our results show that cardiomyocytes possess functional cholinergic machinery that offsets deleterious effects of hyperadrenergic stimulation. In addition, we show that adrenergic stimulation upregulates expression levels of cholinergic components. We propose that this cardiomyocyte cholinergic signaling could amplify the protective effects of the parasympathetic nervous system in the heart and may counteract or partially neutralize hypertrophic adrenergic effects.
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Affiliation(s)
- Cibele Rocha-Resende
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, CEP 31270-901, Brazil.
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Xu XD, Liang L, Cheng H, Wang XH, Jiang FG, Zhuo RX, Zhang XZ. Construction of therapeutic glycopeptide hydrogel as a new substitute for antiproliferative drugs to inhibit postoperative scarring formation. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm32519e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kaurstad G, Alves MN, Kemi OJ, Rolim N, Høydal MA, Wisløff H, Stølen TO, Wisløff U. Chronic CaMKII inhibition blunts the cardiac contractile response to exercise training. Eur J Appl Physiol 2011; 112:579-88. [PMID: 21614506 PMCID: PMC3258410 DOI: 10.1007/s00421-011-1994-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 04/30/2011] [Indexed: 11/29/2022]
Abstract
Activation of the multifunctional Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) plays a critical role modulating cardiac function in both health and disease. Here, we determined the effect of chronic CaMKII inhibition during an exercise training program in healthy mice. CaMKII was inhibited by KN-93 injections. Mice were randomized to the following groups: sham sedentary, sham exercise, KN-93 sedentary, and KN-93 exercise. Cardiorespiratory function was evaluated by ergospirometry during treadmill running, echocardiography, and cardiomyocyte fractional shortening and calcium handling. The results revealed that KN-93 alone had no effect on exercise capacity or fractional shortening. In sham animals, exercise training increased maximal oxygen uptake by 8% (p < 0.05) compared to a 22% (p < 0.05) increase after exercise in KN-93 treated mice (group difference p < 0.01). In contrast, in vivo fractional shortening evaluated by echocardiography improved after exercise in sham animals only: from 25 to 32% (p < 0.02). In inactive mice, KN-93 reduced rates of diastolic cardiomyocyte re-lengthening (by 25%, p < 0.05) as well as Ca(2+) transient decay (by 16%, p < 0.05), whereas no such effect was observed after exercise training. KN-93 blunted exercise training response on cardiomyocyte fractional shortening (63% sham vs. 18% KN-93; p < 0.01 and p < 0.05, respectively). These effects could not be solely explained by the Ca(2+) transient amplitude, as KN-93 reduced it by 20% (p < 0.05) and response to exercise training was equal (64% sham and 47% KN-93; both p < 0.01). We concluded that chronic CaMKII inhibition increased time to 50% re-lengthening which were recovered by exercise training, but paradoxically led to a greater increase in maximal oxygen uptake compared to sham mice. Thus, the effect of chronic CaMKII inhibition is multifaceted and of a complex nature.
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Affiliation(s)
- Guri Kaurstad
- K.G. Jebsen Center of Exercise in Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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34
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Ramay HR, Liu OZ, Sobie EA. Recovery of cardiac calcium release is controlled by sarcoplasmic reticulum refilling and ryanodine receptor sensitivity. Cardiovasc Res 2011; 91:598-605. [PMID: 21613275 DOI: 10.1093/cvr/cvr143] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIMS In heart cells, the mechanisms underlying refractoriness of the elementary units of sarcoplasmic reticulum (SR) Ca(2+) release, Ca(2+) sparks, remain unclear. We investigated local recovery of SR Ca(2+) release using experimental measurements and mathematical modelling. METHODS AND RESULTS Repeated Ca(2+) sparks were induced from individual clusters of ryanodine receptors (RyRs) in quiescent rat ventricular myocytes, and we examined how changes in RyR gating influenced the time-dependent recovery of Ca(2+) spark amplitude and triggering probability. Repeated Ca(2+) sparks from individual sites were analysed in the presence of 50 nM ryanodine with: (i) no additional agents (control); (ii) 50 µM caffeine to sensitize RyRs; (iii) 50 µM tetracaine to inhibit RyRs; or (iv) 100 nM isoproterenol to activate β-adrenergic receptors. Sensitization and inhibition of RyR clusters shortened and lengthened, respectively, the median interval between consecutive Ca(2+) sparks (caffeine 239 ms; control 280 ms; tetracaine 453 ms). Recovery of Ca(2+) spark amplitude, however, was exponential with a time constant of ∼100 ms in all cases. Isoproterenol both accelerated the recovery of Ca(2+) spark amplitude (τ = 58 ms) and shortened the median interval between Ca(2+) sparks (192 ms). The results were recapitulated by a mathematical model in which SR [Ca(2+)] depletion terminates Ca(2+) sparks, but not by an alternative model based on limited depletion and Ca(2+)-dependent inactivation of RyRs. CONCLUSION Together, the results strongly suggest that: (i) local SR refilling controls Ca(2+) spark amplitude recovery; (ii) Ca(2+) spark triggering depends on both refilling and RyR sensitivity; and (iii) β-adrenergic stimulation influences both processes.
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Affiliation(s)
- Hena R Ramay
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, One Gustave Levy Place, Box 1215, New York, NY 10029, USA
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35
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Abstract
Calcium ions play fundamental roles in many cellular processes in virtually all type of cells. The use of Ca(2+) sensitive fluorescent indicators has proven to be an indispensable tool for studying the spatio-temporal dynamics of intracellular calcium ([Ca(2+)](i)). With the aid of laser scanning confocal microscopy and new generation of Ca(2+) indicators, highly localized, short-lived Ca(2+) signals, namely Ca(2+) sparks, were revealed as elementary Ca(2+) release events during excitation-contraction coupling in cardiomyocytes. Since the discovery of Ca(2+) sparks in 1993, the demonstration of dynamic Ca(2+) micro-domains in living cardiomyocytes has revolutionized our understanding of Ca(2+)-mediated signal transduction in normal and diseased hearts. In this chapter, we have described a commonly used method for recording local and global Ca(2+) signals in cardiomyocytes using the fluorescent indicator fluo-4 acetoxymethyl (AM) and laser scanning confocal microscopy.
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Affiliation(s)
- Silvia Guatimosim
- Department of Physiology and Biophysics, ICB, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
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36
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Almeida AP, Andrade AB, Ferreira AJ, Pires ACG, Damasceno DD, Alves MNM, Gomes ERM, Kushmerick C, Lima RF, Prado MAM, Prado VF, Richardson M, Cordeiro MN, Guatimosim S, Gomez M. Antiarrhythmogenic effects of a neurotoxin from the spider Phoneutria nigriventer. Toxicon 2010; 57:217-24. [PMID: 21115025 DOI: 10.1016/j.toxicon.2010.11.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 11/17/2010] [Accepted: 11/22/2010] [Indexed: 10/18/2022]
Abstract
In this study, we evaluated the effects of PhKv, a 4584 Da peptide isolated from the spider Phoneutria nigriventer venom, in the isolated rat heart and in isolated ventricular myocytes. Ventricular arrhythmias were induced by occlusion of the left anterior descending coronary artery for 15 min followed by 30 min of reperfusion. Administration of native PhKv (240 nM) 1 min before or after reperfusion markedly reduced the duration of arrhythmias. This effect was blocked by atropine, thereby indicating the participation of muscarinic receptors in the antiarrhythmogenic effect of PhKv. Notably, recombinant PhKv (240 nM) was also efficient to attenuate the arrhythmias (3.8 ± 0.9 vs. 8.0 ± 1.2 arbitrary units in control group). Furthermore, PhKv induced a significant reduction in heart rate. This bradycardia was partially blunted by atropine and potentiated by pyridostigmine. To further evaluate the participation of acetylcholine on the PhKv effects, we examined the release of this neurotransmitter from neuromuscular junctions. It was found that Phkv (200 nM) significantly increased the release of acetylcholine in this preparation. Moreover, PhKv (250 nM) did not cause any significant change in action potential or Ca(2+) transient parameters in isolated cardiomyocytes. Altogether, these findings show an important acetylcholine-mediated antiarrhythmogenic effect of the spider PhKv toxin in isolated hearts.
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Affiliation(s)
- Alvair P Almeida
- Department of Physiology, ICB, UFMG, Belo Horizonte, Minas Gerais, Brazil
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McNeish AJ, Jimenez Altayo F, Garland CJ. Evidence both L-type and non-L-type voltage-dependent calcium channels contribute to cerebral artery vasospasm following loss of NO in the rat. Vascul Pharmacol 2010; 53:151-9. [PMID: 20601125 PMCID: PMC3191278 DOI: 10.1016/j.vph.2010.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 06/01/2010] [Accepted: 06/12/2010] [Indexed: 11/25/2022]
Abstract
We recently found block of NO synthase in rat middle cerebral artery caused spasm, associated with depolarizing oscillations in membrane potential (Em) similar in form but faster in frequency (circa 1 Hz) to vasomotion. T-type voltage-gated Ca2+ channels contribute to cerebral myogenic tone and vasomotion, so we investigated the significance of T-type and other ion channels for membrane potential oscillations underlying arterial spasm. Smooth muscle cell membrane potential (Em) and tension were measured simultaneously in rat middle cerebral artery. NO synthase blockade caused temporally coupled depolarizing oscillations in cerebrovascular Em with associated vasoconstriction. Both events were accentuated by block of smooth muscle BKCa. Block of T-type channels or inhibition of Na+/K+-ATPase abolished the oscillations in Em and reduced vasoconstriction. Oscillations in Em were either attenuated or accentuated by reducing [Ca2+]o or block of KV, respectively. TRAM-34 attenuated oscillations in both Em and tone, apparently independent of effects against KCa3.1. Thus, rapid depolarizing oscillations in Em and tone observed after endothelial function has been disrupted reflect input from T-type calcium channels in addition to L-type channels, while other depolarizing currents appear to be unimportant. These data suggest that combined block of T and L-type channels may represent an effective approach to reverse cerebral vasospasm.
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Affiliation(s)
- A J McNeish
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
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Dysautonomia due to reduced cholinergic neurotransmission causes cardiac remodeling and heart failure. Mol Cell Biol 2010; 30:1746-56. [PMID: 20123977 DOI: 10.1128/mcb.00996-09] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Overwhelming evidence supports the importance of the sympathetic nervous system in heart failure. In contrast, much less is known about the role of failing cholinergic neurotransmission in cardiac disease. By using a unique genetically modified mouse line with reduced expression of the vesicular acetylcholine transporter (VAChT) and consequently decreased release of acetylcholine, we investigated the consequences of altered cholinergic tone for cardiac function. M-mode echocardiography, hemodynamic experiments, analysis of isolated perfused hearts, and measurements of cardiomyocyte contraction indicated that VAChT mutant mice have decreased left ventricle function associated with altered calcium handling. Gene expression was analyzed by quantitative reverse transcriptase PCR and Western blotting, and the results indicated that VAChT mutant mice have profound cardiac remodeling and reactivation of the fetal gene program. This phenotype was attributable to reduced cholinergic tone, since administration of the cholinesterase inhibitor pyridostigmine for 2 weeks reversed the cardiac phenotype in mutant mice. Our findings provide direct evidence that decreased cholinergic neurotransmission and underlying autonomic imbalance cause plastic alterations that contribute to heart dysfunction.
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Ferreira AJ, Castro CH, Guatimosim S, Almeida PW, Gomes ER, Dias-Peixoto MF, Alves MN, Fagundes-Moura CR, Rentzsch B, Gava E, Almeida AP, Guimarães AM, Kitten GT, Reudelhuber T, Bader M, Santos RA. Attenuation of isoproterenol-induced cardiac fibrosis in transgenic rats harboring an angiotensin-(1-7)-producing fusion protein in the heart. Ther Adv Cardiovasc Dis 2010; 4:83-96. [DOI: 10.1177/1753944709353426] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Objective: It has been shown that Ang-(1-7) has cardioprotective actions. To directly investigate the effects of Ang-(1-7) specifically in the heart, we generated and characterized transgenic (TG) rats which express an Ang-(1-7)-producing fusion protein driven by the α-MHC promoter. Methods and Results: After microinjection of the transgene into fertilized rat zygotes, we obtained four different transgenic lines. Homozygous animals were analyzed with regard to the expression profile of the transgene by ribonuclease protection assay. Transgene expression was detected mainly in the heart with weak or no expression in other organs. Heterozygous TG(hA-1-7)L7301 rats presented a significant increase in cardiac Ang-(1-7) concentration compared with control rats (17.1±2.1 versus 3.9±1.4 pg/mg protein in SD rats). Radiotelemetry analysis revealed that TG rats presented no significant changes in blood pressure and heart rate compared with normal rats. Overexpression of Ang-(1-7) in the heart produced slight improvement in resting cardiac function (+ dT/dt: 81530±1305.0 versus 77470±345.5 g/s bpm in SD rats, p < 0.05), which was in keeping with the enhanced [Ca2+] handling observed in cardiomyocytes of TG rats. TG(hA-1-7)L7301 rats also showed a greater capacity to withstand stress since TG rats showed a less pronounced deposition of collagen type III and fibronectin induced by isoproterenol treatment in the subendocardial area than in corresponding controls. In addition, hearts from TG rats showed reduced incidence and duration of reperfusion arrhythmias in comparison with SD rats. Conclusion: These results indicate that Ang-(1-7) has blood pressure-independent, antifibrotic effects, acting directly in the heart.
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Affiliation(s)
- Anderson J. Ferreira
- Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Carlos H. Castro
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Silvia Guatimosim
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Pedro W.M. Almeida
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Enéas R.M. Gomes
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Márcia N.M. Alves
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Brit Rentzsch
- Max-Delbruck Center for Molecular Medicine Berlin, Germany
| | - Elisandra Gava
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Alvair P. Almeida
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Alexandre M. Guimarães
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Gregory T. Kitten
- Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Timothy Reudelhuber
- Laboratory of Molecular Biochemistry of Hypertension, Clinical Research Institute of Montréal, Québec, Canada
| | - Michael Bader
- Max-Delbruck Center for Molecular Medicine Berlin, Germany
| | - Robson A.S. Santos
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazi, l
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40
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Aguiar CJ, Andrade VL, Gomes ERM, Alves MNM, Ladeira MS, Pinheiro ACN, Gomes DA, Almeida AP, Goes AM, Resende RR, Guatimosim S, Leite MF. Succinate modulates Ca(2+) transient and cardiomyocyte viability through PKA-dependent pathway. Cell Calcium 2009; 47:37-46. [PMID: 20018372 DOI: 10.1016/j.ceca.2009.11.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 10/26/2009] [Accepted: 11/04/2009] [Indexed: 10/20/2022]
Abstract
GPR91 is an orphan G-protein-coupled receptor (GPCR) that has been characterized as a receptor for succinate, a citric acid cycle intermediate, in several tissues. In the heart, the role of succinate is unknown. We now report that rat ventricular cardiomyocytes express GPR91. We found that succinate, through GPR91, increases the amplitude and the rate of decline of global Ca(2+) transient, by increasing the phosphorylation levels of ryanodine receptor and phospholamban, two well known Ca(2+) handling proteins. The effects of succinate on Ca(2+) transient were abolished by pre-treatment with adenylyl cyclase and cAMP-dependent protein kinase (PKA) inhibitors. Direct PKA activation by succinate was further confirmed using a FRET-based A-kinase activity reporter. Additionally, succinate decreases cardiomyocyte viability through a caspase-3 activation pathway, effect also prevented by PKA inhibition. Taken together, these observations show that succinate acts as a signaling molecule in cardiomyocytes, modulating global Ca(2+) transient and cell viability through a PKA-dependent pathway.
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Affiliation(s)
- Carla J Aguiar
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte CEP, Brazil
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41
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Gomes ERM, Lara AA, Almeida PWM, Guimarães D, Resende RR, Campagnole-Santos MJ, Bader M, Santos RAS, Guatimosim S. Angiotensin-(1-7) prevents cardiomyocyte pathological remodeling through a nitric oxide/guanosine 3',5'-cyclic monophosphate-dependent pathway. Hypertension 2009; 55:153-60. [PMID: 19996065 DOI: 10.1161/hypertensionaha.109.143255] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The renin-angiotensin (Ang) system plays a pivotal role in the pathogenesis of cardiovascular disease, with Ang II being the major effector of this system. Multiple lines of evidence have shown that Ang-(1-7) exerts cardioprotective effects in the heart by counterregulating Ang II actions. The questions that remain are how and where Ang-(1-7) exerts its effects. By using a combination of molecular biology, confocal microscopy, and a transgenic rat model with increased levels of circulating Ang-(1-7) (TGR[A1-7]3292), we evaluated the signaling pathways involved in Ang-(1-7) cardioprotection against Ang II-induced pathological remodeling in ventricular cardiomyocytes. Rats were infused with Ang II for 2 weeks. We found that ventricular myocytes from TGR(A1-7)3292 rats are protected from Ang II pathological remodeling characterized by Ca(2+) signaling dysfunction, hypertrophic fetal gene expression, glycogen synthase kinase 3beta inactivation, and nuclear factor of activated T-cells nuclear accumulation. Moreover, cardiomyocytes from TGR(A1-7)3292 rats infused with Ang II presented increased expression levels of neuronal NO synthase. To provide a signaling pathway involved in the beneficial effects of Ang-(1-7), we treated neonatal cardiomyocytes with Ang-(1-7) and Ang II for 36 hours. Treatment of cardiomyocytes with Ang-(1-7) prevented Ang II-induced hypertrophy by modulating calcineurin/nuclear factor of activated T-cell signaling cascade. Importantly, antihypertrophic effects of Ang-(1-7) on Ang II-treated cardiomyocytes were prevented by N(G)-nitro-l-arginine methyl ester and 1H-1,2,4oxadiazolo4,2-aquinoxalin-1-one, suggesting that these effects are mediated by NO/cGMP. Taken together, these data reveal a key role for NO/cGMP as a mediator of Ang-(1-7) beneficial effects in cardiac cells.
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Affiliation(s)
- Enéas R M Gomes
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte MG-CEP: 31270-901, Brazil
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42
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Faust SM, Lu G, Wood SC, Bishop DK. TGFbeta neutralization within cardiac allografts by decorin gene transfer attenuates chronic rejection. THE JOURNAL OF IMMUNOLOGY 2009; 183:7307-13. [PMID: 19917705 DOI: 10.4049/jimmunol.0902736] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Chronic allograft rejection (CR) is the leading cause of late graft failure following organ transplantation. CR is a progressive disease, characterized by deteriorating graft function, interstitial fibrosis, cardiac hypertrophy, and occlusive neointima development. TGFbeta, known for its immunosuppressive qualities, plays a beneficial role in the transplant setting by maintaining alloreactive T cells in a hyporesponsive state, but has also been implicated in promoting graft fibrosis and CR. In the mouse vascularized cardiac allograft model, transient depletion of CD4(+) cells promotes graft survival but leads to CR, which is associated with intragraft TGFbeta expression. Decorin, an extracellular matrix protein, inhibits both TGFbeta bioactivity and gene expression. In this study, gene transfer of decorin into cardiac allografts was used to assess the impact of intragraft TGFbeta neutralization on CR, systemic donor-reactive T cell responses, and allograft acceptance. Decorin gene transfer and neutralization of TGFbeta in cardiac allografts significantly attenuated interstitial fibrosis, cardiac hypertrophy, and improved graft function, but did not result in systemic donor-reactive T cell responses. Thus, donor-reactive T and B cells remained in a hyporesponsive state. These findings indicate that neutralizing intragraft TGFbeta inhibits the cytokine's fibrotic activities, but does not reverse its beneficial systemic immunosuppressive qualities.
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Affiliation(s)
- Susan M Faust
- Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
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43
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Oliveira RSF, Ferreira JCB, Gomes ERM, Paixão NA, Rolim NPL, Medeiros A, Guatimosim S, Brum PC. Cardiac anti-remodelling effect of aerobic training is associated with a reduction in the calcineurin/NFAT signalling pathway in heart failure mice. J Physiol 2009; 587:3899-910. [PMID: 19505981 DOI: 10.1113/jphysiol.2009.173948] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cardiomyocyte hypertrophy occurs in response to a variety of physiological and pathological stimuli. While pathological hypertrophy in heart failure is usually coupled with depressed contractile function, physiological hypertrophy associates with increased contractility. In the present study, we explored whether 8 weeks of moderate intensity exercise training would lead to a cardiac anti-remodelling effect in an experimental model of heart failure associated with a deactivation of a pathological (calcineurin/NFAT, CaMKII/HDAC) or activation of a physiological (Akt-mTOR) hypertrophy signalling pathway. The cardiac dysfunction, exercise intolerance, left ventricle dilatation, increased heart weight and cardiomyocyte hypertrophy from mice lacking alpha(2A) and alpha(2C) adrenoceptors (alpha(2A)/alpha(2C)ARKO mice) were associated with sympathetic hyperactivity induced heart failure. The relative contribution of Ca(2+)-calmodulin high-affinity (calcineurin/NFAT) and low-affinity (CaMKII/HDAC) targets to pathological hypertrophy of alpha(2A)/alpha(2C)ARKO mice was verified. While nuclear calcineurin B, NFATc3 and GATA-4 translocation were significantly increased in alpha(2A)/alpha(2C)ARKO mice, no changes were observed in CaMKII/HDAC activation. As expected, cyclosporine treatment decreased nuclear translocation of calcineurin/NFAT in alpha(2A)/alpha(2C)ARKO mice, which was associated with improved ventricular function and a pronounced anti-remodelling effect. The Akt/mTOR signalling pathway was not activated in alpha(2A)/alpha(2C)ARKO mice. Exercise training improved cardiac function and exercise capacity in alpha(2A)/alpha(2C)ARKO mice and decreased heart weight and cardiomyocyte width paralleled by diminished nuclear NFATc3 and GATA-4 translocation as well as GATA-4 expression levels. When combined, these findings support the notion that deactivation of calcineurin/NFAT pathway-induced pathological hypertrophy is a preferential mechanism by which exercise training leads to the cardiac anti-remodelling effect in heart failure.
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Affiliation(s)
- R S F Oliveira
- School of Physical Education and Sport, University of Sao Paulo, SP, Brazil
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44
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Dias-Peixoto MF, Santos RAS, Gomes ERM, Alves MNM, Almeida PWM, Greco L, Rosa M, Fauler B, Bader M, Alenina N, Guatimosim S. Molecular mechanisms involved in the angiotensin-(1-7)/Mas signaling pathway in cardiomyocytes. Hypertension 2008; 52:542-8. [PMID: 18695148 DOI: 10.1161/hypertensionaha.108.114280] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recently there has been growing evidence suggesting that beneficial effects of angiotensin-(1-7) [Ang-(1-7)] in the heart are mediated by its receptor Mas. However, the signaling pathways involved in these effects in cardiomyocytes are unknown. Here, we investigated the involvement of the Ang-(1-7)/Mas axis in NO generation and Ca(2+) handling in adult ventricular myocytes using a combination of molecular biology, intracellular Ca(2+) imaging, and confocal microscopy. Acute Ang-(1-7) treatment (10 nmol/L) leads to NO production and activates endothelial NO synthase and Akt in cardiomyocytes. Ang-(1-7)-dependent NO raise was abolished by pretreatment with A-779 (1 micromol/L). To confirm that Ang-(1-7) action is mediated by Mas, we used cardiomyocytes isolated from Mas-deficient mice. In Mas-deficient cardiomyocytes, Ang-(1-7) failed to increase NO levels. Moreover, Mas-ablation was accompanied by significant alterations in the proteins involved in the regulation of endothelial NO synthase activity, indicating that endothelial NO synthase and its binding partners are important effectors of the Mas-mediated pathway in cardiomyocytes. We then investigated the role of the Ang-(1-7)/Mas axis on Ca(2+) signaling. Cardiomyocytes treated with 10 nmol/L of Ang-(1-7) did not show changes in Ca(2+)-transient parameters such as peak Ca(2+) transients and kinetics of decay. Nevertheless, cardiomyocytes from Mas-deficient mice presented reduced peak and slower [Ca(2+)](i) transients when compared with wild-type cardiomyocytes. Lower Ca(2+) ATPase of the sarcoplasmic reticulum expression levels accompanied the reduced Ca(2+) transient in Mas-deficient cardiomyocytes. Therefore, chronic Mas-deficiency leads to impaired Ca(2+) handling in cardiomyocytes. Collectively, these observations reveal a key role for the Ang-(1-7)/Mas axis as a modulator of cardiomyocyte function.
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Affiliation(s)
- Marco F Dias-Peixoto
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
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45
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Bartholomeu JB, Vanzelli AS, Rolim NP, Ferreira JC, Bechara LR, Tanaka LY, Rosa KT, Alves MM, Medeiros A, Mattos KC, Coelho MA, Irigoyen MC, Krieger EM, Krieger JE, Negrão CE, Ramires PR, Guatimosim S, Brum PC. Intracellular mechanisms of specific β-adrenoceptor antagonists involved in improved cardiac function and survival in a genetic model of heart failure. J Mol Cell Cardiol 2008; 45:240-9. [DOI: 10.1016/j.yjmcc.2008.05.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 05/16/2008] [Accepted: 05/16/2008] [Indexed: 12/15/2022]
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46
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Guatimosim S, Amaya MJ, Guerra MT, Aguiar CJ, Goes AM, Gómez-Viquez NL, Rodrigues MA, Gomes DA, Martins-Cruz J, Lederer WJ, Leite MF. Nuclear Ca2+ regulates cardiomyocyte function. Cell Calcium 2008; 44:230-42. [PMID: 18201761 DOI: 10.1016/j.ceca.2007.11.016] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Revised: 10/30/2007] [Accepted: 11/30/2007] [Indexed: 01/19/2023]
Abstract
In the heart, cytosolic Ca(2+) signals are well-characterized events that participate in the activation of cell contraction. In contrast, nuclear Ca(2+) contribution to cardiomyocyte function remains elusive. Here, we examined functional consequences of buffering nuclear Ca(2+) in neonatal cardiomyocytes. We report that cardiomyocytes contain a nucleoplasmic reticulum, which expresses both ryanodine receptor (RyR) and inositol 1,4,5-trisphosphate receptor (InsP(3)R), providing a possible way for active regulation of nuclear Ca(2+). Adenovirus constructs encoding the Ca(2+) buffer protein parvalbumin were targeted to the nucleus with a nuclear localization signal (Ad-PV-NLS) or to the cytoplasm with a nuclear exclusion signal (Ad-PV-NES). A decrease in the amplitude of global Ca(2+) transients and RyR-II expression, as well as an increase in cell beating rate were observed in Ad-PV-NES and Ad-PV-NLS cells. When nuclear Ca(2+) buffering was imposed nuclear enlargement, increased calcineurin expression, NFAT translocation to the nucleus and subcellular redistribution of atrial natriuretic peptide were observed. Furthermore, prolongation of action potential duration occurred in adult ventricular myocytes. These results suggest that nuclear Ca(2+) levels underlie the regulation of specific protein targets and thereby modulate cardiomyocyte function. The local nuclear Ca(2+) signaling and the structures that control it constitute a novel regulatory motif in the heart.
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Affiliation(s)
- Silvia Guatimosim
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte CEP: 31270-901, Brazil
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47
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Ogura K, Miake J, Sasaki N, Iwai C, Bahrudin U, Li P, Kato M, Iitsuka K, Hirota Y, Koshida T, Yamamoto Y, Inoue Y, Yano A, Adachi M, Igawa O, Kurata Y, Morisaki T, Shiota G, Shirayoshi Y, Haruaki N, Hisatome I. Inhibition of beta-adrenergic signaling by intracellular AMP is independent of cell-surface adenosine receptors in rat cardiac cells. J Mol Cell Cardiol 2007; 43:648-52. [PMID: 17888450 DOI: 10.1016/j.yjmcc.2007.07.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 07/24/2007] [Indexed: 10/23/2022]
Abstract
We report a novel action of intracellular adenosine monophosphate (AMP) to inhibit beta-adrenergic signaling in isolated rat ventricular myocytes. Extracellular application of adenosine or AMP suppressed isoproterenol (Iso)-induced prolongation of action potential duration (APD). This effect was completely abolished by an A(1)-receptor antagonist, DPCPX. Intracellular application of AMP, but not adenosine, attenuated Iso-induced APD prolongation. Iso-induced increases in the L-type Ca(2+) current (I(Ca,L)) were also inhibited by intracellular AMP. These inhibitory effects were not affected by either DPCPX or glibenclamide. In vitro, AMP directly inhibited PKA activity via binding to its regulatory subunit. These results suggest that intracellular AMP attenuates beta-adrenergic signaling by directly inhibiting PKA activity, independently of A(1)-purinergic receptor.
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Affiliation(s)
- Kazuyoshi Ogura
- Department of Cardiovascular Medicine, Tottori University Faculty of Medicine, Japan
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48
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McNulty MM, Kyle JW, Lipkind GM, Hanck DA. An inner pore residue (Asn406) in the Nav1.5 channel controls slow inactivation and enhances mibefradil block to T-type Ca2+ channel levels. Mol Pharmacol 2006; 70:1514-23. [PMID: 16885209 DOI: 10.1124/mol.106.027177] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mibefradil is a tetralol derivative once marketed to treat hyper-tension. Its primary target is the T-type Ca(2+) channel (IC(50), approximately 0.1-0.2 microM), but it also blocks Na(+),K(+),Cl(-), and other Ca(2+) channels at higher concentrations. We have recently reported state-dependent mibefradil block of Na(+) channels in which apparent affinity was enhanced when channels were recruited to slow-inactivated conformations. The structural determinants controlling mibefradil block have not been identified, although evidence suggests involvement of regions near or within the inner pore. We tested whether mibefradil interacts with the local anesthetic (LA) binding site, which includes residues in the S6 segments of domains (D) I, III, and IV. Mutagenesis of DIII S6 and DIVS6 did not reveal critical binding determinants. Substitution of Asn406 in DI S6 of cardiac Na(v)1.5, however, altered affinity in a manner dependent on the identity of the substituting residue. Replacing Asn406 with a phenylalanine or a cysteine increased affinity by 4- and 7-fold, respectively, thus conferring T-type Ca(2+) channel-like mibefradil sensitivity to the Na(+) channel. A series of other substitutions that varied in size, charge, and hydrophobicity had minimal effects on mibefradil block, but all mutations dramatically altered the magnitude and voltage-dependence of slow inactivation, consistent with data in other isoforms. Channels did not slow-inactivate, however, at the voltages used to assay mibefradil block, supporting the idea that Asn406 lies within or near the mibefradil binding site.
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Affiliation(s)
- Megan M McNulty
- Department of Medicine, University of Chicago, 5841 S. Maryland Ave, MC6094, IL 60637, USA
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49
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Santos RAS, Castro CH, Gava E, Pinheiro SVB, Almeida AP, Paula RDD, Cruz JS, Ramos AS, Rosa KT, Irigoyen MC, Bader M, Alenina N, Kitten GT, Ferreira AJ. Impairment of in vitro and in vivo heart function in angiotensin-(1-7) receptor MAS knockout mice. Hypertension 2006; 47:996-1002. [PMID: 16567589 DOI: 10.1161/01.hyp.0000215289.51180.5c] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this study we investigated the effects of the genetic deletion of the angiotensin (Ang)-(1-7) receptor Mas on heart function. Localization of Mas in the mouse heart was evaluated by binding of rhodamine-labeled Ang-(1-7). Cardiac function was examined using isolated heart preparations. Echocardiography was used to confirm the results obtained with isolated heart studies. To elucidate the possible mechanisms involved in the cardiac phenotype observed in Mas(-/-) mice, whole-cell calcium currents in cardiomyocytes and the expression of collagen types I, III, and VI and fibronectin were analyzed. Ang-(1-7) binding showed that Mas is localized in cardiomyocytes of the mouse heart. Isolated heart techniques revealed that Mas-deficient mice present a lower systolic tension (average: 1.4+/-0.09 versus 2.1+/-0.03 g in Mas(+/+) mice), +/-dT/dt, and heart rate. A significantly higher coronary vessel resistance was also observed in Mas-deficient mice. Echocardiography revealed that hearts of Mas-deficient mice showed a significantly decreased fractional shortening, posterior wall thickness in systole and left ventricle end-diastolic dimension, and a higher left ventricle end-systolic dimension. A markedly lower global ventricular function, as defined by a higher myocardial performance index, was observed. A higher delayed time to the peak of calcium current was also observed. The changes in cardiac function could be partially explained by a marked change in collagen expression to a profibrotic profile in Mas-deficient mice. These results indicate that Ang-(1-7)-Mas axis plays a key role in the maintenance of the structure and function of the heart.
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Affiliation(s)
- Robson A S Santos
- Department of Physiology and Biophysics, Biological Sciences Institute, Belo Horizonte, MG, Brazil.
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50
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Chorvatova A, Snowdon R, Hart G, Hussain M. Effects of pressure overload-induced hypertrophy on TTX-sensitive inward currents in guinea pig left ventricle. Mol Cell Biochem 2005; 261:217-26. [PMID: 15362507 DOI: 10.1023/b:mcbi.0000028759.22274.cf] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We investigated the effects of pressure overload hypertrophy on inward sodium (I Na) and calcium currents (I Ca) in single left ventricular myocytes to determine whether changes in these current systems could account for the observed prolongation of the action potential. Hypertrophy was induced by pressure overload caused by banding of the abdominal aorta. Whole-cell patch clamp experiments were used to measure tetrodotoxin (TTX)-sensitive inward currents. The main findings were that I Ca density was unchanged whereas I Na density after stepping from -80 to -30 mV was decreased by 30% (-9.0 +/- 1.16 pA pF(-1) in control and -6.31 +/- 0.67 pA pF(-1) in hypertrophy, p < 0.05, n = 6). Steady-state activation/inactivation variables of I Na, determined by using double-pulse protocols, were similar in control and hypertrophied myocytes, whereas the time course of fast inactivation of I Na was slowed (p < 0.05) in hypertrophied myocytes. In addition, action potential clamp experiments were carried out in the absence and presence of TTX under conditions where only Ca2+ was likely to enter the cell via TTX-sensitive channels. We show for the first time that a TTX-sensitive inward current was present during the plateau phase of the action potential in hypertrophied but not control myocytes. The observed decrease in I Na density is likely to abbreviate rather than prolong the action potential. Delayed fast inactivation of Na+ channels was not sustained throughout the voltage pulse and may therefore merely counteract the effect of decreased I Na density so that net Na+ influx remains unaltered. Changes in the fast I Na do not therefore appear to contribute to lengthening of the action potential in this model of hypertrophy. However, the presence of a TTX-sensitive current during the plateau could potentially contribute to the prolongation of the action potential in hypertrophied cardiac muscle.
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Affiliation(s)
- Alzbeta Chorvatova
- Department of Medicine, University Clinical Departments, Duncan Building, Daulby Street, Liverpool, L69 3GA, UK
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