1
|
Lookin O, Protsenko Y. The Slow Force Response and Simultaneous Changes in Ca2+ Transient in Healthy and Failing Rat Atrial and Ventricular Myocardium. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022070043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
2
|
Di Mattía RA, Díaz Zegarra LA, Valverde CA, Blanco PG, Jaquenod De Giusti C, Portiansky EL, Aiello EA, Orlowski A. In vivo Overexpression of Electrogenic Sodium/Bicarbonate Cotransporter (NBCe1) by AAV9 Modifies the Cardiac Action Potential and the QT Interval in Mice. Front Cardiovasc Med 2022; 9:862118. [PMID: 35548416 PMCID: PMC9082548 DOI: 10.3389/fcvm.2022.862118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 03/23/2022] [Indexed: 11/29/2022] Open
Abstract
Cardiac cells depend on specific sarcolemmal ion transporters to assure the correct intracellular pH regulation. The sodium/bicarbonate cotransporter (NBC) is one of the major alkalinizing mechanisms. In the heart two different NBC isoforms have been described: the electroneutral NBCn1 (1Na+:1HCO3-) and the electrogenic NBCe1 (1Na+:2HCO3-). NBCe1 generates an anionic repolarizing current that modulates the action potential duration (APD). In addition to regulating the pH, the NBC is a source of sodium influx. It has been postulated that NBC could play a role in the development of hypertrophy. The aim of this research was to study the contribution of NBCe1 in heart electrophysiology and in the development of heart hypertrophy in an in vivo mouse model with overexpression of NBCe1. Heart NBCe1 overexpression was achieved by a recombinant cardiotropic adeno-associated virus (AAV9) and was evidenced by western-blot and qPCR. AAV9-mCherry was used as a transduction control. NBCe1 overexpression fails to increase heart growth. Patch clamp and electrocardiogram were performed. We observed a reduction on both, ventricular myocytes APD and electrocardiogram QT interval corrected by cardiac rate, emphasizing for the first time NBCe1 relevance for the electrical activity of the heart.
Collapse
Affiliation(s)
- Romina A. Di Mattía
- Centro de Investigaciones Cardiovasculares “Dr. Horacio E. Cingolani, ” Facultad de Ciencias Médicas, Universidad Nacional de La Plata-CONICET, La Plata, Argentina
| | - Leandro A. Díaz Zegarra
- Centro de Investigaciones Cardiovasculares “Dr. Horacio E. Cingolani, ” Facultad de Ciencias Médicas, Universidad Nacional de La Plata-CONICET, La Plata, Argentina
| | - Carlos A. Valverde
- Centro de Investigaciones Cardiovasculares “Dr. Horacio E. Cingolani, ” Facultad de Ciencias Médicas, Universidad Nacional de La Plata-CONICET, La Plata, Argentina
| | - Paula G. Blanco
- Centro de Fisiología Reproductiva y Métodos Complementarios de Diagnóstico, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata-CONICET, La Plata, Argentina
| | - Carolina Jaquenod De Giusti
- Centro de Investigaciones Cardiovasculares “Dr. Horacio E. Cingolani, ” Facultad de Ciencias Médicas, Universidad Nacional de La Plata-CONICET, La Plata, Argentina
| | - Enrique L. Portiansky
- Laboratorio de Análisis de Imágenes, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata-CONICET, La Plata, Argentina
| | - Ernesto A. Aiello
- Centro de Investigaciones Cardiovasculares “Dr. Horacio E. Cingolani, ” Facultad de Ciencias Médicas, Universidad Nacional de La Plata-CONICET, La Plata, Argentina
- *Correspondence: Ernesto A. Aiello
| | - Alejandro Orlowski
- Centro de Investigaciones Cardiovasculares “Dr. Horacio E. Cingolani, ” Facultad de Ciencias Médicas, Universidad Nacional de La Plata-CONICET, La Plata, Argentina
- Alejandro Orlowski
| |
Collapse
|
3
|
Syomin F, Osepyan A, Tsaturyan A. Computationally efficient model of myocardial electromechanics for multiscale simulations. PLoS One 2021; 16:e0255027. [PMID: 34293046 PMCID: PMC8297763 DOI: 10.1371/journal.pone.0255027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/08/2021] [Indexed: 11/19/2022] Open
Abstract
A model of myocardial electromechanics is suggested. It combines modified and simplified versions of previously published models of cardiac electrophysiology, excitation-contraction coupling, and mechanics. The mechano-calcium and mechano-electrical feedbacks, including the strain-dependence of the propagation velocity of the action potential, are also accounted for. The model reproduces changes in the twitch amplitude and Ca2+-transients upon changes in muscle strain including the slow response. The model also reproduces the Bowditch effect and changes in the twitch amplitude and duration upon changes in the interstimulus interval, including accelerated relaxation at high stimulation frequency. Special efforts were taken to reduce the stiffness of the differential equations of the model. As a result, the equations can be integrated numerically with a relatively high time step making the model suitable for multiscale simulation of the human heart and allowing one to study the impact of myocardial mechanics on arrhythmias.
Collapse
Affiliation(s)
- Fyodor Syomin
- Institute of Mechanics, Lomonosov Moscow State University, Moscow, Russia
- * E-mail:
| | - Anna Osepyan
- Institute of Mechanics, Lomonosov Moscow State University, Moscow, Russia
| | - Andrey Tsaturyan
- Institute of Mechanics, Lomonosov Moscow State University, Moscow, Russia
| |
Collapse
|
4
|
Seo K, Parikh VN, Ashley EA. Stretch-Induced Biased Signaling in Angiotensin II Type 1 and Apelin Receptors for the Mediation of Cardiac Contractility and Hypertrophy. Front Physiol 2020; 11:181. [PMID: 32231588 PMCID: PMC7082839 DOI: 10.3389/fphys.2020.00181] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/17/2020] [Indexed: 12/18/2022] Open
Abstract
The myocardium has an intrinsic ability to sense and respond to mechanical load in order to adapt to physiological demands. Primary examples are the augmentation of myocardial contractility in response to increased ventricular filling caused by either increased venous return (Frank-Starling law) or aortic resistance to ejection (the Anrep effect). Sustained mechanical overload, however, can induce pathological hypertrophy and dysfunction, resulting in heart failure and arrhythmias. It has been proposed that angiotensin II type 1 receptor (AT1R) and apelin receptor (APJ) are primary upstream actors in this acute myocardial autoregulation as well as the chronic maladaptive signaling program. These receptors are thought to have mechanosensing capacity through activation of intracellular signaling via G proteins and/or the multifunctional transducer protein, β-arrestin. Importantly, ligand and mechanical stimuli can selectively activate different downstream signaling pathways to promote inotropic, cardioprotective or cardiotoxic signaling. Studies to understand how AT1R and APJ integrate ligand and mechanical stimuli to bias downstream signaling are an important and novel area for the discovery of new therapeutics for heart failure. In this review, we provide an up-to-date understanding of AT1R and APJ signaling pathways activated by ligand versus mechanical stimuli, and their effects on inotropy and adaptive/maladaptive hypertrophy. We also discuss the possibility of targeting these signaling pathways for the development of novel heart failure therapeutics.
Collapse
Affiliation(s)
- Kinya Seo
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
| | - Victoria N. Parikh
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
| | - Euan A. Ashley
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
- Department of Genetics, Stanford University, Stanford, CA, United States
| |
Collapse
|
5
|
Kaur S, Shen X, Power A, Ward ML. Stretch modulation of cardiac contractility: importance of myocyte calcium during the slow force response. Biophys Rev 2020; 12:135-142. [PMID: 31939110 DOI: 10.1007/s12551-020-00615-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 01/07/2020] [Indexed: 12/11/2022] Open
Abstract
The mechanical response of the heart to myocardial stretch has been understood since the work of muscle physiologists more than 100 years ago, whereby an increase in ventricular chamber filling during diastole increases the subsequent force of contraction. The stretch-induced increase in contraction is biphasic. There is an abrupt increase in the force that coincides with the stretch (the rapid response), which is then followed by a slower response that develops over several minutes (the slow force response, or SFR). The SFR is associated with a progressive increase in the magnitude of the Ca2+ transient, the event that initiates myocyte cross-bridge cycling and force development. However, the mechanisms underlying the stretch-dependent increase in the Ca2+ transient are still debated. This review outlines recent literature on the SFR and summarizes the different stretch-activated Ca2+ entry pathways. The SFR might result from a combination of several different cellular mechanisms initiated in response to activation of different cellular stretch sensors.
Collapse
Affiliation(s)
- Sarbjot Kaur
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Xin Shen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G.Jebsen Center for Cardiac Research, Oslo, Norway
| | - Amelia Power
- Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Marie-Louise Ward
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| |
Collapse
|
6
|
Yeves AM, Ennis IL. Na +/H + exchanger and cardiac hypertrophy. HIPERTENSION Y RIESGO VASCULAR 2019; 37:22-32. [PMID: 31601481 DOI: 10.1016/j.hipert.2019.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 08/16/2019] [Accepted: 09/03/2019] [Indexed: 12/31/2022]
Abstract
Reactive cardiac hypertrophy (CH) is an increase in heart mass in response to hemodynamic overload. Exercise-induced CH emerges as an adaptive response with improved cardiac function, in contrast to pathological CH that represents a risk factor for cardiovascular health. The Na+/H+ exchanger (NHE-1) is a membrane transporter that not only regulates intracellular pH but also intracellular Na+ concentration. In the scenario of cardiovascular diseases, myocardial NHE-1 is activated by a variety of stimuli, such as neurohumoral factors and mechanical stress, leading to intracellular Na+ overload and activation of prohypertrophic cascades. NHE-1 hyperactivity is intimately linked to heart diseases, including ischemia-reperfusion injury, maladaptive CH and heart failure. In this review, we will present evidence to support that the NHE-1 hyperactivity constitutes a "switch on/off" for the pathological phenotype during CH development. We will also discuss some classical and novel strategies to avoid NHE-1 hyperactivity, and that are therefore worthwhile to improve cardiovascular health.
Collapse
Affiliation(s)
- A M Yeves
- Centro de Investigaciones Cardiovasculares "Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata - CONICET, Calle 60 y 120, 1900 La Plata, Argentina
| | - I L Ennis
- Centro de Investigaciones Cardiovasculares "Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata - CONICET, Calle 60 y 120, 1900 La Plata, Argentina.
| |
Collapse
|
7
|
Dowrick JM, Tran K, Loiselle DS, Nielsen PMF, Taberner AJ, Han J, Ward M. The slow force response to stretch: Controversy and contradictions. Acta Physiol (Oxf) 2019; 226:e13250. [PMID: 30614655 DOI: 10.1111/apha.13250] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/20/2018] [Accepted: 01/02/2019] [Indexed: 12/19/2022]
Abstract
When exposed to an abrupt stretch, cardiac muscle exhibits biphasic active force enhancement. The initial, instantaneous, force enhancement is well explained by the Frank-Starling mechanism. However, the cellular mechanisms associated with the second, slower phase remain contentious. This review explores hypotheses regarding this "slow force response" with the intention of clarifying some apparent contradictions in the literature. The review is partitioned into three sections. The first section considers pathways that modify the intracellular calcium handling to address the role of the sarcoplasmic reticulum in the mechanism underlying the slow force response. The second section focuses on extracellular calcium fluxes and explores the identity and contribution of the stretch-activated, non-specific, cation channels as well as signalling cascades associated with G-protein coupled receptors. The final section introduces promising candidates for the mechanosensor(s) responsible for detecting the stretch perturbation.
Collapse
Affiliation(s)
- Jarrah M. Dowrick
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Kenneth Tran
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Denis S. Loiselle
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
- Department of Physiology University of Auckland Auckland New Zealand
| | - Poul M. F. Nielsen
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
- Department of Engineering Science University of Auckland Auckland New Zealand
| | - Andrew J. Taberner
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
- Department of Engineering Science University of Auckland Auckland New Zealand
| | - June‐Chiew Han
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Marie‐Louise Ward
- Department of Physiology University of Auckland Auckland New Zealand
| |
Collapse
|
8
|
Baker HE, Kiel AM, Luebbe ST, Simon BR, Earl CC, Regmi A, Roell WC, Mather KJ, Tune JD, Goodwill AG. Inhibition of sodium-glucose cotransporter-2 preserves cardiac function during regional myocardial ischemia independent of alterations in myocardial substrate utilization. Basic Res Cardiol 2019; 114:25. [PMID: 31004234 PMCID: PMC6616532 DOI: 10.1007/s00395-019-0733-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 04/09/2019] [Indexed: 12/11/2022]
Abstract
The goal of the present study was to evaluate the effects of SGLT2i on cardiac contractile function, substrate utilization, and efficiency before and during regional myocardial ischemia/reperfusion injury in normal, metabolically healthy swine. Lean swine received placebo or canagliflozin (300 mg PO) 24 h prior to and the morning of an invasive physiologic study protocol. Hemodynamic and cardiac function measurements were obtained at baseline, during a 30-min complete occlusion of the circumflex coronary artery, and during a 2-h reperfusion period. Blood pressure, heart rate, coronary flow, and myocardial oxygen consumption were unaffected by canagliflozin treatment. Ventricular volumes remained unchanged in controls throughout the protocol. At the onset of ischemia, canagliflozin produced acute large increases in left ventricular end-diastolic and systolic volumes which returned to baseline with reperfusion. Canagliflozin-mediated increases in end-diastolic volume were directly associated with increases in stroke volume and stroke work relative to controls during ischemia. Canagliflozin also increased cardiac work efficiency during ischemia relative to control swine. No differences in myocardial uptake of glucose, lactate, free fatty acids or ketones, were noted between treatment groups at any time. In separate experiments using a longer 60 min coronary occlusion followed by 2 h of reperfusion, canagliflozin increased end-diastolic volume and stroke volume and significantly diminished myocardial infarct size relative to control swine. These data demonstrate that SGLT2i with canagliflozin preserves cardiac contractile function and efficiency during regional myocardial ischemia and provides ischemia protection independent of alterations in myocardial substrate utilization.
Collapse
Affiliation(s)
- Hana E Baker
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Alexander M Kiel
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Samuel T Luebbe
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Blake R Simon
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Conner C Earl
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Ajit Regmi
- Diabetes and Complications Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - William C Roell
- Diabetes and Complications Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Kieren J Mather
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Johnathan D Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Adam G Goodwill
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA.
| |
Collapse
|
9
|
Ibañez AM, Espejo MS, Zavala MR, Villa-Abrille MC, Lofeudo JM, Aiello EA, De Giusti VC. Regulation of Intracellular pH is Altered in Cardiac Myocytes of Ovariectomized Rats. J Am Heart Assoc 2019; 8:e011066. [PMID: 30917747 PMCID: PMC6509710 DOI: 10.1161/jaha.118.011066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background It is well known that after menopause women are exposed to a greater cardiovascular risk, but the intracellular modifications are not properly described. The sodium/proton exchanger (NHE) and the sodium/bicarbonate cotransporter (NBC) regulate the intracellular pH and, indirectly, the intracellular sodium concentration ([Na+]). There are 2 isoforms of NBC in the heart: the electrogenic (1Na+/2[Formula: see text]; NBCe1) and the electroneutral (1Na+/1[Formula: see text]; NBCn1). Because NHE and NBCn1 hyperactivity as well as the NBCe1 decreased activity have been associated with several cardiovascular pathologies, the aim of this study was to investigate the potential alterations of the alkalinizing transporters during the postmenopausal period. Methods and Results Three-month ovariectomized rats (OVX) were used. The NHE activity and protein expression are significantly increased in OVX. The NBCe1 activity is diminished, and the NBCn1 activity becomes predominant in OVX rats. p-Akt levels showed a significant diminution in OVX. Finally, NHE activity in platelets from OVX rats is also higher in comparison to sham rats, resulting in a potential biomarker of cardiovascular diseases. Conclusions Our results demonstrated for the first time that in the cardiac ventricular myocytes of OVX rats NHE and NBC isoforms are altered, probably because of the decreased level of p-Akt, compromising the ionic intracellular homeostasis.
Collapse
Affiliation(s)
- Alejandro Martín Ibañez
- 1 Centro de Investigaciones Cardiovasculares Facultad de Ciencias Médicas Universidad Nacional de La Plata-CONICET La Plata Argentina
| | - María Sofía Espejo
- 1 Centro de Investigaciones Cardiovasculares Facultad de Ciencias Médicas Universidad Nacional de La Plata-CONICET La Plata Argentina
| | - Maite Raquel Zavala
- 1 Centro de Investigaciones Cardiovasculares Facultad de Ciencias Médicas Universidad Nacional de La Plata-CONICET La Plata Argentina
| | - María Celeste Villa-Abrille
- 1 Centro de Investigaciones Cardiovasculares Facultad de Ciencias Médicas Universidad Nacional de La Plata-CONICET La Plata Argentina
| | - Juan Manuel Lofeudo
- 1 Centro de Investigaciones Cardiovasculares Facultad de Ciencias Médicas Universidad Nacional de La Plata-CONICET La Plata Argentina
| | - Ernesto Alejandro Aiello
- 1 Centro de Investigaciones Cardiovasculares Facultad de Ciencias Médicas Universidad Nacional de La Plata-CONICET La Plata Argentina
| | - Verónica Celeste De Giusti
- 1 Centro de Investigaciones Cardiovasculares Facultad de Ciencias Médicas Universidad Nacional de La Plata-CONICET La Plata Argentina
| |
Collapse
|
10
|
Silencing of the Na+/H+ exchanger 1(NHE-1) prevents cardiac structural and functional remodeling induced by angiotensin II. Exp Mol Pathol 2019; 107:1-9. [DOI: 10.1016/j.yexmp.2019.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 01/08/2019] [Accepted: 01/16/2019] [Indexed: 12/30/2022]
|
11
|
van der Velden J, Stienen GJM. Cardiac Disorders and Pathophysiology of Sarcomeric Proteins. Physiol Rev 2019; 99:381-426. [PMID: 30379622 DOI: 10.1152/physrev.00040.2017] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The sarcomeric proteins represent the structural building blocks of heart muscle, which are essential for contraction and relaxation. During recent years, it has become evident that posttranslational modifications of sarcomeric proteins, in particular phosphorylation, tune cardiac pump function at rest and during exercise. This delicate, orchestrated interaction is also influenced by mutations, predominantly in sarcomeric proteins, which cause hypertrophic or dilated cardiomyopathy. In this review, we follow a bottom-up approach starting from a description of the basic components of cardiac muscle at the molecular level up to the various forms of cardiac disorders at the organ level. An overview is given of sarcomere changes in acquired and inherited forms of cardiac disease and the underlying disease mechanisms with particular reference to human tissue. A distinction will be made between the primary defect and maladaptive/adaptive secondary changes. Techniques used to unravel functional consequences of disease-induced protein changes are described, and an overview of current and future treatments targeted at sarcomeric proteins is given. The current evidence presented suggests that sarcomeres not only form the basis of cardiac muscle function but also represent a therapeutic target to combat cardiac disease.
Collapse
Affiliation(s)
- Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Ger J M Stienen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| |
Collapse
|
12
|
Kim JC, Son MJ, Woo SH. Regulation of cardiac calcium by mechanotransduction: Role of mitochondria. Arch Biochem Biophys 2018; 659:33-41. [DOI: 10.1016/j.abb.2018.09.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 09/28/2018] [Indexed: 12/27/2022]
|
13
|
Yamaguchi Y, Iribe G, Kaneko T, Takahashi K, Numaga-Tomita T, Nishida M, Birnbaumer L, Naruse K. TRPC3 participates in angiotensin II type 1 receptor-dependent stress-induced slow increase in intracellular Ca 2+ concentration in mouse cardiomyocytes. J Physiol Sci 2018; 68:153-164. [PMID: 28105583 PMCID: PMC10718017 DOI: 10.1007/s12576-016-0519-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 12/26/2016] [Indexed: 11/26/2022]
Abstract
When a cardiac muscle is held in a stretched position, its [Ca2+] transient increases slowly over several minutes in a process known as stress-induced slow increase in intracellular Ca2+ concentration ([Ca2+]i) (SSC). Transient receptor potential canonical (TRPC) 3 forms a non-selective cation channel regulated by the angiotensin II type 1 receptor (AT1R). In this study, we investigated the role of TRPC3 in the SSC. Isolated mouse ventricular myocytes were electrically stimulated and subjected to sustained stretch. An AT1R blocker, a phospholipase C inhibitor, and a TRPC3 inhibitor suppressed the SSC. These inhibitors also abolished the observed SSC-like slow increase in [Ca2+]i induced by angiotensin II, instead of stretch. Furthermore, the SSC was not observed in TRPC3 knockout mice. Simulation and immunohistochemical studies suggest that sarcolemmal TRPC3 is responsible for the SSC. These results indicate that sarcolemmal TRPC3, regulated by AT1R, causes the SSC.
Collapse
Affiliation(s)
- Yohei Yamaguchi
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan
| | - Gentaro Iribe
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan.
| | - Toshiyuki Kaneko
- Department of Physiology, Asahikawa Medical University, Asahikawa, Hokkaido, 078-8510, Japan
| | - Ken Takahashi
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan
| | - Takuro Numaga-Tomita
- Division of Cardiocirculatory Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
| | - Motohiro Nishida
- Division of Cardiocirculatory Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Science, Research Triangle Park, NC, 27709, USA
| | - Keiji Naruse
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan
| |
Collapse
|
14
|
Kim JC, Son MJ, Wang J, Woo SH. Regulation of cardiac Ca 2+ and ion channels by shear mechanotransduction. Arch Pharm Res 2017; 40:783-795. [PMID: 28702845 DOI: 10.1007/s12272-017-0929-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 07/06/2017] [Indexed: 11/25/2022]
Abstract
Cardiac contraction is controlled by a Ca2+ signaling sequence that includes L-type Ca2+ current-gated opening of Ca2+ release channels (ryanodine receptors) in the sarcoplasmic reticulum (SR). Local Ca2+ signaling in the atrium differs from that in the ventricle because atrial myocytes lack transverse tubules and have more abundant corbular SR. Myocardium is subjected to a variety of forces with each contraction, such as stretch, shear stress, and afterload, and adapts to those mechanical stresses. These mechanical stimuli increase in heart failure, hypertension, and valvular heart diseases that are clinically implicated in atrial fibrillation and stroke. In the present review, we describe distinct responses of atrial and ventricular myocytes to shear stress and compare them with other mechanical responses in the context of local and global Ca2+ signaling and ion channel regulation. Recent evidence suggests that shear mechanotransduction in cardiac myocytes involves activation of gap junction hemichannels, purinergic signaling, and generation of mitochondrial reactive oxygen species. Significant alterations in Ca2+ signaling and ionic currents by shear stress may be implicated in the pathogenesis of cardiac arrhythmia and failure.
Collapse
Affiliation(s)
- Joon-Chul Kim
- College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 305-764, South Korea
| | - Min-Jeong Son
- College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 305-764, South Korea
| | - Jun Wang
- College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 305-764, South Korea
| | - Sun-Hee Woo
- College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 305-764, South Korea.
| |
Collapse
|
15
|
Schönleitner P, Schotten U, Antoons G. Mechanosensitivity of microdomain calcium signalling in the heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017. [PMID: 28648626 DOI: 10.1016/j.pbiomolbio.2017.06.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In cardiac myocytes, calcium (Ca2+) signalling is tightly controlled in dedicated microdomains. At the dyad, i.e. the narrow cleft between t-tubules and junctional sarcoplasmic reticulum (SR), many signalling pathways combine to control Ca2+-induced Ca2+ release during contraction. Local Ca2+ gradients also exist in regions where SR and mitochondria are in close contact to regulate energetic demands. Loss of microdomain structures, or dysregulation of local Ca2+ fluxes in cardiac disease, is often associated with oxidative stress, contractile dysfunction and arrhythmias. Ca2+ signalling at these microdomains is highly mechanosensitive. Recent work has demonstrated that increasing mechanical load triggers rapid local Ca2+ releases that are not reflected by changes in global Ca2+. Key mechanisms involve rapid mechanotransduction with reactive oxygen species or nitric oxide as primary signalling molecules targeting SR or mitochondria microdomains depending on the nature of the mechanical stimulus. This review summarizes the most recent insights in rapid Ca2+ microdomain mechanosensitivity and re-evaluates its (patho)physiological significance in the context of historical data on the macroscopic role of Ca2+ in acute force adaptation and mechanically-induced arrhythmias. We distinguish between preload and afterload mediated effects on local Ca2+ release, and highlight differences between atrial and ventricular myocytes. Finally, we provide an outlook for further investigation in chronic models of abnormal mechanics (eg post-myocardial infarction, atrial fibrillation), to identify the clinical significance of disturbed Ca2+ mechanosensitivity for arrhythmogenesis.
Collapse
Affiliation(s)
- Patrick Schönleitner
- Dept of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands
| | - Uli Schotten
- Dept of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands
| | - Gudrun Antoons
- Dept of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands.
| |
Collapse
|
16
|
Role of TRPC3 and TRPC6 channels in the myocardial response to stretch: Linking physiology and pathophysiology. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017. [PMID: 28645743 DOI: 10.1016/j.pbiomolbio.2017.06.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Transient receptor potential (TRP) channels constitute a large family of versatile multi-signal transducers. In particular, TRP canonical (TRPC) channels are known as receptor-operated, non-selective cation channels. TRPC3 and TRPC6, two members in the TRPC family, are highly expressed in the heart, and participate in the pathogenesis of cardiac hypertrophy and heart failure as a pathological response to chronic mechanical stress. In the pathological response, myocardial stretch increases intracellular Ca2+ levels and activates nuclear factor of activated T cells to induce cardiac hypertrophy. Recent studies have revealed that TRPC3 and TRPC6 also contribute to the physiological stretch-induced slow force response (SFR), a slow increase in the Ca2+ transient and twitch force during stretch. In the physiological response, a stretch-induced increase in intracellular Ca2+ mediated by TRPC3 and TRPC6 causes the SFR. We here overview experimental evidence of the involvement of TRPC3 and TRPC6 in cardiac physiology and pathophysiology in response to stretch.
Collapse
|
17
|
Kim JC, Wang J, Son MJ, Woo SH. Shear stress enhances Ca 2+ sparks through Nox2-dependent mitochondrial reactive oxygen species generation in rat ventricular myocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1121-1131. [PMID: 28213332 DOI: 10.1016/j.bbamcr.2017.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/01/2017] [Accepted: 02/12/2017] [Indexed: 02/06/2023]
Abstract
Shear stress enhances diastolic and systolic Ca2+ concentration in ventricular myocytes. Here, using confocal Ca2+ imaging in rat ventricular myocytes, we assessed the effects of shear stress (~16dyn/cm2) on the frequency of spontaneous Ca2+ sparks and explored the mechanism underlying shear-mediated Ca2+ spark regulation. The frequency of Ca2+ sparks was immediately increased by shear stress (by ~80%), and increased further (by ~150%) during prolonged exposure (20s). The 2-D size and duration of individual sparks were increased by shear stimulation. Inhibition of nitric oxide synthase (NOS) only partially attenuated the prolonged shear-mediated enhancement in spark frequency. Pretreatment with antioxidants significantly attenuated the short- and long-term effects of shear on spark frequency. Microtubule or nicotinamide adenine dinucleotide phosphate oxidase 2 (Nox2) inhibition abolished the immediate shear-induced increase in spark frequency and suppressed the effects of prolonged exposure to shear stress by ~70%. Scavenging of mitochondrial reactive oxygen species (ROS) and mitochondrial uncoupling also abolished the effect of short-term shear on spark occurrence, and markedly reduced (by ~80%) the effects of prolonged shear. Mitochondrial ROS levels increased under shear; this was eliminated by blocking Nox2. Sarcoplasmic reticulum Ca2+ content was increased only by prolonged shear. Our data suggest that shear stress enhances ventricular spark frequency mainly via ROS generated from mitochondria through Nox2, and that NOS and higher sarcoplasmic reticulum Ca2+ concentrations may also contribute to the enhancement of Ca2+ sparks under shear stress. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
Collapse
Affiliation(s)
- Joon-Chul Kim
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, South Korea
| | - Jun Wang
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, South Korea
| | - Min-Jeong Son
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, South Korea
| | - Sun-Hee Woo
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, South Korea.
| |
Collapse
|
18
|
β-Arrestin mediates the Frank-Starling mechanism of cardiac contractility. Proc Natl Acad Sci U S A 2016; 113:14426-14431. [PMID: 27911784 DOI: 10.1073/pnas.1609308113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Frank-Starling law of the heart is a physiological phenomenon that describes an intrinsic property of heart muscle in which increased cardiac filling leads to enhanced cardiac contractility. Identified more than a century ago, the Frank-Starling relationship is currently known to involve length-dependent enhancement of cardiac myofilament Ca2+ sensitivity. However, the upstream molecular events that link cellular stretch to the length-dependent myofilament Ca2+ sensitivity are poorly understood. Because the angiotensin II type 1 receptor (AT1R) and the multifunctional transducer protein β-arrestin have been shown to mediate mechanosensitive cellular signaling, we tested the hypothesis that these two proteins are involved in the Frank-Starling mechanism of the heart. Using invasive hemodynamics, we found that mice lacking β-arrestin 1, β-arrestin 2, or AT1R were unable to generate a Frank-Starling force in response to changes in cardiac volume. Although wild-type mice pretreated with the conventional AT1R blocker losartan were unable to enhance cardiac contractility with volume loading, treatment with a β-arrestin-biased AT1R ligand to selectively activate β-arrestin signaling preserved the Frank-Starling relationship. Importantly, in skinned muscle fiber preparations, we found markedly impaired length-dependent myofilament Ca2+ sensitivity in β-arrestin 1, β-arrestin 2, and AT1R knockout mice. Our data reveal β-arrestin 1, β-arrestin 2, and AT1R as key regulatory molecules in the Frank-Starling mechanism, which potentially can be targeted therapeutically with β-arrestin-biased AT1R ligands.
Collapse
|
19
|
Brea MS, Díaz RG, Escudero DS, Caldiz CI, Portiansky EL, Morgan PE, Pérez NG. Epidermal Growth Factor Receptor Silencing Blunts the Slow Force Response to Myocardial Stretch. J Am Heart Assoc 2016; 5:JAHA.116.004017. [PMID: 27744404 PMCID: PMC5121502 DOI: 10.1161/jaha.116.004017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background Myocardial stretch increases force biphasically: the Frank‐Starling mechanism followed by the slow force response (SFR). Based on pharmacological strategies, we proposed that epidermal growth factor (EGF) receptor (EGFR or ErbB1) activation is crucial for SFR development. Pharmacological inhibitors could block ErbB4, a member of the ErbB family present in the adult heart. We aimed to specifically test the role of EGFR activation after stretch, with an interference RNA incorporated into a lentiviral vector (small hairpin RNA [shRNA]‐EGFR). Methods and Results Silencing capability of p‐shEGFR was assessed in EGFR‐GFP transiently transfected HEK293T cells. Four weeks after lentivirus injection into the left ventricular wall of Wistar rats, shRNA‐EGFR–injected hearts showed ≈60% reduction of EGFR protein expression compared with shRNA‐SCR–injected hearts. ErbB2 and ErbB4 expression did not change. The SFR to stretch evaluated in isolated papillary muscles was ≈130% of initial rapid phase in the shRNA‐SCR group, while it was blunted in shRNA‐EGFR–expressing muscles. Angiotensin II (Ang II)‐dependent Na+/H+ exchanger 1 activation was indirectly evaluated by intracellular pH measurements in bicarbonate‐free medium, demonstrating an increase in shRNA‐SCR–injected myocardium, an effect not observed in the silenced group. Ang II‐ or EGF‐triggered reactive oxygen species production was significantly reduced in shRNA‐EGFR–injected hearts compared with that in the shRNA‐SCR group. Chronic lentivirus treatment affected neither the myocardial basal redox state (thiobarbituric acid reactive substances) nor NADPH oxidase activity or expression. Finally, Ang II or EGF triggered a redox‐sensitive pathway, leading to p90RSK activation in shRNA‐SCR‐injected myocardium, an effect that was absent in the shRNA‐EGFR group. Conclusions Our results provide evidence that specific EGFR activation after myocardial stretch is a key factor in promoting the redox‐sensitive kinase activation pathway, leading to SFR development.
Collapse
Affiliation(s)
- María S Brea
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Romina G Díaz
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Daiana S Escudero
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Claudia I Caldiz
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Enrique L Portiansky
- Laboratorio de Análisis de Imágenes, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Buenos Aires, Argentina
| | - Patricio E Morgan
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Néstor G Pérez
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| |
Collapse
|
20
|
Rainer PP, Kass DA. Old dog, new tricks: novel cardiac targets and stress regulation by protein kinase G. Cardiovasc Res 2016; 111:154-62. [PMID: 27297890 DOI: 10.1093/cvr/cvw107] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/18/2016] [Indexed: 12/11/2022] Open
Abstract
The second messenger cyclic guanosine 3'5' monophosphate (cGMP) and its downstream effector protein kinase G (PKG) have been discovered more than 40 years ago. In vessels, PKG1 induces smooth muscle relaxation in response to nitric oxide signalling and thus lowers systemic and pulmonary blood pressure. In platelets, PKG1 stimulation by cGMP inhibits activation and aggregation, and in experimental models of heart failure (HF), PKG1 activation by inhibiting cGMP degradation is protective. The net effect of the above-mentioned signalling is cardiovascular protection. Yet, while modulation of cGMP-PKG has entered clinical practice for treating pulmonary hypertension or erectile dysfunction, translation of promising studies in experimental HF to clinical success has failed thus far. With the advent of new technologies, novel mechanisms of PKG regulation, including mechanosensing, redox regulation, protein quality control, and cGMP degradation, have been discovered. These novel, non-canonical roles of PKG1 may help understand why clinical translation has disappointed thus far. Addressing them appears to be a requisite for future, successful translation of experimental studies to the clinical arena.
Collapse
Affiliation(s)
- Peter P Rainer
- Division of Cardiology, Medical University of Graz, Auenbruggerplatz 15, A-8036 Graz, Austria
| | - David A Kass
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| |
Collapse
|
21
|
Lookin ON, Protsenko YL. The kinetics of cytosolic calcium in the right ventricular myocardium of guinea pigs and rats. Biophysics (Nagoya-shi) 2016. [DOI: 10.1134/s0006350916010140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
22
|
Yeves AM, Villa-Abrille MC, Pérez NG, Medina AJ, Escudero EM, Ennis IL. Physiological cardiac hypertrophy: critical role of AKT in the prevention of NHE-1 hyperactivity. J Mol Cell Cardiol 2014; 76:186-95. [PMID: 25240639 DOI: 10.1016/j.yjmcc.2014.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 08/28/2014] [Accepted: 09/06/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND The involvement of NHE-1 hyperactivity, critical for pathological cardiac hypertrophy (CH), in physiological CH has not been elucidated yet. Stimulation of NHE-1 increases intracellular Na(+) and Ca(2+) favouring calcineurin activation. Since myocardial stretch, an activator of NHE-1, is common to both types of CH, we speculate that NHE-1 hyperactivity may also happen in physiological CH. However, calcineurin activation is characteristic only for pathological hypertrophy. We hypothesize that an inhibitory AKT-dependent mechanism prevents NHE-1 hyperactivity in the setup of physiological CH. METHODS Physiological CH was induced in rats by swimming (90 min/day, 12 weeks) or in cultured isolated cardiomyocytes with IGF-1 (10 nmol/L). RESULTS Training induced eccentric CH development (left ventricular weight/tibial length: 22.0±0.3 vs. 24.3±0.7 mg/mm; myocyte cross sectional area: 100±3.2 vs. 117±4.1 %; sedentary (Sed) and swim-trained (Swim) respectively; p<0.05] with decreased myocardial stiffness and collagen deposition [1.7±0.05 % (Sed) vs. 1.4±0.09 % (Swim); p<0.05]. Increased phosphorylation of AKT, ERK1/2, p90(RSK) and NHE-1 at the consensus site for ERK1/2-p90(RSK) were detected in the hypertrophied hearts (P-AKT: 134±10 vs. 100±5; P-ERK1/2: 164±17 vs. 100±18; P-p90(RSK): 160±18 vs. 100±9; P-NHE-1 134±10 vs. 100±10; % in Swim vs. Sed respectively; p<0.05). No significant changes were detected neither in calcineurin activation [calcineurin Aβ 100±10 (Sed) vs. 96±12 (Swim)], nor NFAT nuclear translocation [100±3.11 (Sed) vs. 95±9.81 % (Swim)] nor NHE-1 expression [100±8.5 (Sed) vs. 95±6.7 % (Swim)]. Interestingly, the inhibitory phosphorylation of the NHE-1 consensus site for AKT was increased in the hypertrophied myocardium (151.6±19.4 (Swim) vs. 100±9.5 % (Sed); p<0.05). In isolated cardiomyocytes 24 hours IGF-1 increased cell area (114±1.3 %; p<0.05) and protein/DNA content (115±3.9 %, p<0.05), effects not abolished by NHE-1 inhibition with cariporide (114±3 and 117±4.4 %, respectively). IGF-1 significantly decreased NHE-1 activity during pHi recovery from sustained intracellular acidosis (JH+ at pHi 6.8: 4.08±0.74 and 9.09±1.21 mmol/L/min, IGF-1 vs. control; p<0.05), and abolished myocardial slow force response, the mechanical counterpart of stretch-induced NHE-1 activation. CONCLUSIONS NHE-1 hyperactivity seems not to be involved in physiological CH development, contrary to what characterizes pathological CH. We propose that AKT, through an inhibitory phosphorylation of the NHE-1, prevents its stretch-induced activation. This posttranslational modification emerges as an adaptive mechanism that avoids NHE-1 hyperactivity preserving its housekeeping functioning.
Collapse
Affiliation(s)
- Alejandra M Yeves
- Centro de Investigaciones Cardiovasculares, , Facultad de Ciencias Médicas, UNLP-CONICET, Argentina
| | - María C Villa-Abrille
- Centro de Investigaciones Cardiovasculares, , Facultad de Ciencias Médicas, UNLP-CONICET, Argentina
| | - Néstor G Pérez
- Centro de Investigaciones Cardiovasculares, , Facultad de Ciencias Médicas, UNLP-CONICET, Argentina
| | - Andrés J Medina
- Centro de Investigaciones Cardiovasculares, , Facultad de Ciencias Médicas, UNLP-CONICET, Argentina
| | - Eduardo M Escudero
- Centro de Investigaciones Cardiovasculares, , Facultad de Ciencias Médicas, UNLP-CONICET, Argentina
| | - Irene L Ennis
- Centro de Investigaciones Cardiovasculares, , Facultad de Ciencias Médicas, UNLP-CONICET, Argentina.
| |
Collapse
|
23
|
Ennis IL, Aiello EA, Cingolani HE, Perez NG. The autocrine/paracrine loop after myocardial stretch: mineralocorticoid receptor activation. Curr Cardiol Rev 2014; 9:230-40. [PMID: 23909633 PMCID: PMC3780348 DOI: 10.2174/1573403x113099990034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 12/13/2012] [Indexed: 01/13/2023] Open
Abstract
The stretch of cardiac muscle increases developed force in two phases. The first phase, which occurs rapidly, constitutes the well-known Frank-Starling mechanism and it is generally attributed to enhanced myofilament responsiveness to Ca(2+). The second phase or slow force response (SFR) occurs gradually and is due to an increase in the calcium transient amplitude as a result of a stretch-triggered autocrine/paracrine mechanism. We previously showed that Ca(2+) entry through reverse Na(+)/Ca(2+) exchange underlies the SFR, as the final step of an autocrine/paracrine cascade involving release of angiotensin II/endothelin, and a Na(+)/H(+) exchanger (NHE-1) activation-mediated rise in Na+. In the present review we mainly focus on our three latest contributions to the understanding of this signalling pathway triggered by myocardial stretch: 1) The finding that an increased production of reactive oxygen species (ROS) from mitochondrial origin is critical in the activation of the NHE-1 and therefore in the genesis of the SFR; 2) the demonstration of a key role played by the transactivation of the epidermal growth factor receptor; and 3) the involvement of mineralocorticoid receptors (MR) activation in the stretch-triggered cascade leading to the SFR. Among these novel contributions, the critical role played by the MR is perhaps the most important one. This finding may conceivably provide a mechanistic explanation to the recently discovered strikingly beneficial effects of MR antagonism in humans with cardiac hypertrophy and failure.
Collapse
Affiliation(s)
- Irene L Ennis
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Medicas, Universidad Nacional de La Plata, Argentina
| | | | | | | |
Collapse
|
24
|
Recent insights in the paracrine modulation of cardiomyocyte contractility by cardiac endothelial cells. BIOMED RESEARCH INTERNATIONAL 2014; 2014:923805. [PMID: 24745027 PMCID: PMC3972907 DOI: 10.1155/2014/923805] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 01/04/2023]
Abstract
The cardiac endothelium is formed by a continuous monolayer of cells that line the cavity of the heart (endocardial endothelial cells (EECs)) and the luminal surface of the myocardial blood vessels (intramyocardial capillary endothelial cells (IMCEs)). EECs and IMCEs can exercise substantial control over the contractility of cardiomyocytes by releasing various factors such as nitric oxide (NO) via a constitutive endothelial NO-synthase (eNOS), endothelin-1, prostaglandins, angiotensin II, peptide growth factors, and neuregulin-1. The purpose of the present paper is actually to shortly review recent new information concerning cardiomyocytes as effectors of endothelium paracrine signaling, focusing particularly on contractile function. The modes of action and the regulatory paracrine role of the main mediators delivered by cardiac endothelial cells upon cardiac contractility identified in cardiomyocytes are complex and not fully described. Thus, careful evaluation of new therapeutic approaches is required targeting important physiological signaling pathways, some of which have been until recently considered as deleterious, like reactive oxygen species. Future works in the field of cardiac endothelial cells and cardiac function will help to better understand the implication of these mediators in cardiac physiopathology.
Collapse
|
25
|
Correa MV, Nolly MB, Caldiz CI, de Cingolani GEC, Cingolani HE, Ennis IL. Endogenous endothelin 1 mediates angiotensin II-induced hypertrophy in electrically paced cardiac myocytes through EGFR transactivation, reactive oxygen species and NHE-1. Pflugers Arch 2013; 466:1819-30. [PMID: 24327206 DOI: 10.1007/s00424-013-1413-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 01/20/2023]
Abstract
Emerging evidence supports a key role for endothelin-1 (ET-1) and the transactivation of the epidermal growth factor receptor (EGFR) in angiotensin II (Ang II) action. We aim to determine the potential role played by endogenous ET-1, EGFR transactivation and redox-dependent sodium hydrogen exchanger-1 (NHE-1) activation in the hypertrophic response to Ang II of cardiac myocytes. Electrically paced adult cat cardiomyocytes were placed in culture and stimulated with 1 nmol l(-1) Ang II or 5 nmol l(-1) ET-1. Ang II increased ~45 % cell surface area (CSA) and ~37 % [(3)H]-phenylalanine incorporation, effects that were blocked not only by losartan (Los) but also by BQ123 (AT1 and ETA receptor antagonists, respectively). Moreover, Ang II significantly increased ET-1 messenger RNA (mRNA) expression. ET-1 similarly increased myocyte CSA and protein synthesis, actions prevented by the reactive oxygen species scavenger MPG or the NHE-1 inhibitor cariporide (carip). ET-1 increased the phosphorylation of the redox-sensitive ERK1/2-p90(RSK) kinases, main activators of the NHE-1. This effect was prevented by MPG and the antagonist of EGFR, AG1478. Ang II, ET-1 and EGF increased myocardial superoxide production (187 ± 9 %, 149 ± 8 % and 163.7 ± 6 % of control, respectively) and AG1478 inhibited these effects. Interestingly, Los inhibited only Ang II whilst BQ123 cancelled both Ang II and ET-1 actions, supporting the sequential and unidirectional activation of AT1, ETA and EGFR. Based on the present evidence, we propose that endogenous ET-1 mediates the hypertrophic response to Ang II by a mechanism that involves EGFR transactivation and redox-dependent activation of the ERK1/2-p90(RSK) and NHE-1 in adult cardiomyocytes.
Collapse
Affiliation(s)
- María V Correa
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120 S/N, La Plata, 1900, Argentina,
| | | | | | | | | | | |
Collapse
|
26
|
Orlowski A, Ciancio MC, Caldiz CI, De Giusti VC, Aiello EA. Reduced sarcolemmal expression and function of the NBCe1 isoform of the Na⁺-HCO₃⁻ cotransporter in hypertrophied cardiomyocytes of spontaneously hypertensive rats: role of the renin-angiotensin system. Cardiovasc Res 2013; 101:211-9. [PMID: 24253522 DOI: 10.1093/cvr/cvt255] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
AIMS Electroneutral (NBCn1) and electrogenic (NBCe1) isoforms of the Na(+)-HCO3(-) cotransporter (NBC) coexist in the heart. We studied the expression and function of these isoforms in hearts of Wistar and spontaneously hypertensive rats (SHR), elucidating the direct implication of the renin-angiotensin system in the NBC regulation. METHODS AND RESULTS We used myocytes from Wistar, SHR, losartan-treated SHR (Los-SHR), and Angiotensin II (Ang II)-induced cardiac hypertrophy. We found an overexpression of NBCe1 and NBCn1 proteins in SHR that was prevented in Los-SHR. Hyperkalaemic-induced pHi alkalization was used to study selective activation of NBCe1. Despite the increase in NBCe1 expression, its activity was lower in SHR than in Wistar or Los-SHR. Similar results were found in Ang II-induced hypertrophy. A specific inhibitory antibody against NBCe1 allowed the discrimination between NBCe1 and NBCn1 activity. Whereas in SHR most of the pHi recovery was due to NBCn1 stimulation, in Wistar and Los-SHR the activity of both isoforms was equitable, suggesting that the deteriorated cardiac NBCe1 function observed in SHR is compensated by an enhanced activity of NBCn1. Using the biotin method, we observed greater level of internalized NBCe1 protein in SHR than in the non-hypertophic groups, while with immunofluorescence we localized the protein in endosomes near the nucleus only in SHR. CONCLUSIONS We conclude that Ang II is responsible for the impairment of the NBCe1 in hypertrophied hearts. This is due to retained transporter protein units in early endosomes. Moreover, NBCn1 activity seems to be increased in the hypertrophic myocardium of SHR, compensating impaired function of NBCe1.
Collapse
Affiliation(s)
- Alejandro Orlowski
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata-CONICET, Calle 60 y 120, 1900 La Plata, Argentina
| | | | | | | | | |
Collapse
|
27
|
Shen X, Cannell MB, Ward ML. Effect of SR load and pH regulatory mechanisms on stretch-dependent Ca(2+) entry during the slow force response. J Mol Cell Cardiol 2013; 63:37-46. [PMID: 23880608 DOI: 10.1016/j.yjmcc.2013.07.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 06/11/2013] [Accepted: 07/11/2013] [Indexed: 12/22/2022]
Abstract
When cardiac muscle is stretched, there is an initial inotropic response that coincides with the stretch followed by a slower increase in twitch force that develops over several minutes (the "slow force response", or SFR). Unlike the initial response to stretch, the SFR is produced by an increase in Ca(2+) transient amplitude, but the cellular mechanisms that give rise to the increased transients are still debated. We have examined the relationship between the SFR, intracellular [Ca(2+)] and the inotropic state of right ventricular trabeculae from rat hearts at 37°C. The magnitude of the SFR varied with [Ca(2+)]o and stimulation frequency, so that the SFR was greatest for conditions associated with a reduced SR Ca(2+) content. The SFR was not blocked by the AT1 receptor blocker losartan, but was reduced by SN-6, an inhibitor of reverse mode Na(+)/Ca(2+)-exchange (NCX). The Na(+)/H(+)-exchange (NHE) inhibitor HOE642 had no effect in HCO3(-)-buffered solutions, but blocked 50% of the SFR in HCO3(-)-free solution. Inhibition of HCO3(-) transport by DIDS increased the SFR and made it sensitive to HOE642. The addition of cross-bridge cycle inhibitors (20mM BDM or 20μM blebbistatin) to the superfusate reduced the SFR as monitored by changes in Ca(2+). In HCO3(-)-free conditions, the SFR was associated with a slow acidification that was inhibited by BDM, and by stopping electrical stimulation. These results can be explained by stretch increasing metabolic demand and stimulating Na(+) entry via both NHE and the Na(+)/HCO3(-) transporters. This mechanism provides a novel link between inotropic state and stretch, as well as a way for the cell to compensate for increased acid load. The feedback mechanism between force and Ca(2+) transient amplitude that we describe is also limited by the degree of SR Ca(2+) load.
Collapse
Affiliation(s)
- Xin Shen
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand
| | | | | |
Collapse
|
28
|
De Giusti VC, Caldiz CI, Ennis IL, Pérez NG, Cingolani HE, Aiello EA. Mitochondrial reactive oxygen species (ROS) as signaling molecules of intracellular pathways triggered by the cardiac renin-angiotensin II-aldosterone system (RAAS). Front Physiol 2013; 4:126. [PMID: 23755021 PMCID: PMC3667248 DOI: 10.3389/fphys.2013.00126] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 05/13/2013] [Indexed: 12/22/2022] Open
Abstract
Mitochondria represent major sources of basal reactive oxygen species (ROS) production of the cardiomyocyte. The role of ROS as signaling molecules that mediate different intracellular pathways has gained increasing interest among physiologists in the last years. In our lab, we have been studying the participation of mitochondrial ROS in the intracellular pathways triggered by the renin-angiotensin II-aldosterone system (RAAS) in the myocardium during the past few years. We have demonstrated that acute activation of cardiac RAAS induces mitochondrial ATP-dependent potassium channel (mitoKATP) opening with the consequent enhanced production of mitochondrial ROS. These oxidant molecules, in turn, activate membrane transporters, as sodium/hydrogen exchanger (NHE-1) and sodium/bicarbonate cotransporter (NBC) via the stimulation of the ROS-sensitive MAPK cascade. The stimulation of such effectors leads to an increase in cardiac contractility. In addition, it is feasible to suggest that a sustained enhanced production of mitochondrial ROS induced by chronic cardiac RAAS, and hence, chronic NHE-1 and NBC stimulation, would also result in the development of cardiac hypertrophy.
Collapse
Affiliation(s)
- V C De Giusti
- Facultad de Ciencias Médicas, Centro de Investigaciones Cardiovasculares, UNLP-CONICET La Plata, Argentina
| | | | | | | | | | | |
Collapse
|
29
|
Vargas LA, Díaz RG, Swenson ER, Pérez NG, Álvarez BV. Inhibition of carbonic anhydrase prevents the Na(+)/H(+) exchanger 1-dependent slow force response to rat myocardial stretch. Am J Physiol Heart Circ Physiol 2013; 305:H228-37. [PMID: 23709596 DOI: 10.1152/ajpheart.00055.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Myocardial stretch is an established signal that leads to hypertrophy. Myocardial stretch induces a first immediate force increase followed by a slow force response (SFR), which is a consequence of an increased Ca(2+) transient that follows the NHE1 Na(+)/H(+) exchanger activation. Carbonic anhydrase II (CAII) binds to the extreme COOH terminus of NHE1 and regulates its transport activity. We aimed to test the role of CAII bound to NHE1 in the SFR. The SFR and changes in intracellular pH (pHi) were evaluated in rat papillary muscle bathed with CO2/HCO3(-) buffer and stretched from 92% to 98% of the muscle maximal force development length for 10 min in the presence of the CA inhibitor 6-ethoxzolamide (ETZ, 100 μM). SFR control was 120 ± 3% (n = 8) of the rapid initial phase and was fully blocked by ETZ (99 ± 4%, n = 6). The SFR corresponded to a maximal increase in pHi of 0.18 ± 0.02 pH units (n = 4), and pHi changes were blocked by ETZ (0.04 ± 0.04, n = 6), as monitored by epifluorescence. NHE1/CAII physical association was examined in the SFR by coimmunoprecipitation, using muscle lysates. CAII immunoprecipitated with an anti-NHE1 antibody and the CAII immunoprecipitated protein levels increased 58 ± 9% (n = 6) upon stretch of muscles, assessed by immunoblots. The p90(RSK) kinase inhibitor SL0101-1 (10 μM) blocked the SFR of heart muscles after stretch 102 ± 2% (n = 4) and reduced the binding of CAII to NHE1, suggesting that the stretch-induced phosphorylation of NHE1 increases its binding to CAII. CAII/NHE1 interaction constitutes a component of the SFR to heart muscle stretch, which potentiates NHE1-mediated H(+) transport in the myocardium.
Collapse
Affiliation(s)
- Lorena A Vargas
- Centro de Investigaciones Cardiovasculares, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | | | | | | | | |
Collapse
|
30
|
Regulation of the cardiac Na⁺/H⁺ exchanger in health and disease. J Mol Cell Cardiol 2013; 61:68-76. [PMID: 23429007 DOI: 10.1016/j.yjmcc.2013.02.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/07/2013] [Accepted: 02/11/2013] [Indexed: 11/21/2022]
Abstract
The Na(+) gradient produced across the cardiac sarcolemma by the ATP-dependent Na(+)-pump is a constant source of energy for Na(+)-dependent transporters. The plasma membrane Na(+)/H(+) exchanger (NHE) is one such secondary active transporter, regulating intracellular pH, Na(+) concentration, and cell volume. NHE1, the major isoform found in the heart, is activated in response to a variety of stimuli such as hormones and mechanical stress. This important characteristic of NHE1 is intimately linked to heart diseases, including maladaptive cardiac hypertrophy and subsequent heart failure, as well as acute ischemic-reperfusion injury. NHE1 activation results in elevation of pH and intracellular Na(+) concentration, which potentially enhance downstream signaling cascades in the myocardium. Therefore, in addition to determining the mechanism underlying regulation of NHE1 activity, it is important to understand how the ionic signal produced by NHE1 is transmitted to the downstream targets. Extensive studies have identified many accessory factors that interact with NHE1. Here, we have summarized the recent progress on understanding the molecular mechanism underlying NHE1 regulation and have shown a possible signaling pathway leading to cardiac remodeling, which is initiated from NHE1. This article is part of a Special Issue entitled "Na(+) Regulation in Cardiac Myocytes".
Collapse
|
31
|
Alvarez BV, Quon AL, Mullen J, Casey JR. Quantification of carbonic anhydrase gene expression in ventricle of hypertrophic and failing human heart. BMC Cardiovasc Disord 2013; 13:2. [PMID: 23297731 PMCID: PMC3570296 DOI: 10.1186/1471-2261-13-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 12/17/2012] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Carbonic anhydrase enzymes (CA) catalyze the reversible hydration of carbon dioxide to bicarbonate in mammalian cells. Trans-membrane transport of CA-produced bicarbonate contributes significantly to cellular pH regulation. A body of evidence implicates pH-regulatory processes in the hypertrophic growth pathway characteristic of hearts as they fail. In particular, Na+/H+ exchange (NHE) activation is pro-hypertrophic and CA activity activates NHE. Recently Cardrase (6-ethoxyzolamide), a CA inhibitor, was found to prevent and revert agonist-stimulated cardiac hypertrophy (CH) in cultured cardiomyocytes. Our goal thus was to determine whether hypertrophied human hearts have altered expression of CA isoforms. METHODS We measured CA expression in hypertrophied human hearts to begin to examine the role of carbonic anhydrase in progression of human heart failure. Ventricular biopsies were obtained from patients undergoing cardiac surgery (CS, n = 14), or heart transplantation (HT, n = 13). CS patients presented mild/moderate concentric left ventricular hypertrophy and normal right ventricles, with preserved ventricular function; ejection fractions were ~60%. Conversely, HT patients with failing hearts presented CH or ventricular dilation accompanied by ventricular dysfunction and EF values of 20%. Non-hypertrophic, non-dilated ventricular samples served as controls. RESULTS Expression of atrial and brain natriuretic peptide (ANP and BNP) were markers of CH. Hypertrophic ventricles presented increased expression of CAII, CAIV, ANP, and BNP, mRNA levels, which increased in failing hearts, measured by quantitative real-time PCR. CAII, CAIV, and ANP protein expression also increased approximately two-fold in hypertrophic/dilated ventricles. CONCLUSIONS These results, combined with in vitro data that CA inhibition prevents and reverts CH, suggest that increased carbonic anhydrase expression is a prognostic molecular marker of cardiac hypertrophy.
Collapse
Affiliation(s)
| | - Anita L Quon
- Department of Biochemistry, and Membrane Protein Disease Research Group, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - John Mullen
- Department of Surgery, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Joseph R Casey
- Department of Biochemistry, and Membrane Protein Disease Research Group, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| |
Collapse
|
32
|
Brown BF, Quon A, Dyck JRB, Casey JR. Carbonic anhydrase II promotes cardiomyocyte hypertrophy. Can J Physiol Pharmacol 2012; 90:1599-610. [PMID: 23210439 DOI: 10.1139/y2012-142] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pathological cardiac hypertrophy, the maladaptive remodelling of the myocardium, often progresses to heart failure. The sodium-proton exchanger (NHE1) and chloride-bicarbonate exchanger (AE3) have been implicated as important in the hypertrophic cascade. Carbonic anhydrase II (CAII) provides substrates for these transporters (protons and bicarbonate, respectively). CAII physically interacts with NHE1 and AE3, enhancing their respective ion transport activities by increasing the concentration of substrate at their transport sites. Earlier studies found that a broad-spectrum carbonic anhydrase inhibitor prevented cardiomyocyte hypertrophy (CH), suggesting that carbonic anhydrase is important in the development of hypertrophy. Here we investigated whether cytosolic CAII was the CA isoform involved in hypertrophy. Neonatal rat ventricular myocytes (NRVMs) were transduced with recombinant adenoviral constructs to over-express wild-type or catalytically inactive CAII (CAII-V143Y). Over-expression of wild-type CAII in NRVMs did not affect CH development. In contrast, CAII-V143Y over-expression suppressed the response to hypertrophic stimuli, suggesting that CAII-V143Y behaves in a dominant negative fashion over endogenous CAII to suppress hypertrophy. We also examined CAII-deficient (Car2) mice, whose hearts exhibit physiological hypertrophy without any decrease in cardiac function. Moreover, cardiomyocytes from Car2 mice do not respond to prohypertrophic stimulation. Together, these findings support a role of CAII in promoting CH.
Collapse
Affiliation(s)
- Brittany F Brown
- Membrane Protein Disease Research Group, Department of Biochemistry, School of Translational Medicine, University of Alberta, Edmonton, AB, Canada
| | | | | | | |
Collapse
|
33
|
Abstract
Myocardial stretch elicits a rapid increase in developed force, which is mainly caused by an increase in myofilament calcium sensitivity (Frank-Starling mechanism). Over the ensuing 10-15 min, a second gradual increase in force takes place. This slow force response to stretch is known to be the result of an increase in the calcium transient amplitude and constitutes the in vitro equivalent of the Anrep effect described 100 years ago in the intact heart. In the present review, we will update and discuss what is known about the Anrep effect as the mechanical counterpart of autocrine/paracrine mechanisms involved in its genesis. The chain of events triggered by myocardial stretch comprises 1) release of angiotensin II, 2) release of endothelin, 3) activation of the mineralocorticoid receptor, 4) transactivation of the epidermal growth factor receptor, 5) increased formation of mitochondria reactive oxygen species, 6) activation of redox-sensitive kinases upstream myocardial Na(+)/H(+) exchanger (NHE1), 7) NHE1 activation, 8) increase in intracellular Na(+) concentration, and 9) increase in Ca(2+) transient amplitude through the Na(+)/Ca(2+) exchanger. We will present the experimental evidence supporting each of the signaling steps leading to the Anrep effect and its blunting by silencing NHE1 expression with a specific small hairpin interference RNA injected into the ventricular wall.
Collapse
Affiliation(s)
- Horacio E Cingolani
- Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata, La Plata, Argentina.
| | | | | | | |
Collapse
|
34
|
Chen MZ, Bu QT, Pang SC, Li FL, Sun MN, Chu EF, Li H. Tetrodotoxin attenuates isoproterenol-induced hypertrophy in H9c2 rat cardiac myocytes. Mol Cell Biochem 2012; 371:77-88. [DOI: 10.1007/s11010-012-1424-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 08/01/2012] [Indexed: 11/30/2022]
|
35
|
Brines L, Such-Miquel L, Gallego D, Trapero I, del Canto I, Zarzoso M, Soler C, Pelechano F, Cánoves J, Alberola A, Such L, Chorro FJ. Modifications of mechanoelectric feedback induced by 2,3-butanedione monoxime and Blebbistatin in Langendorff-perfused rabbit hearts. Acta Physiol (Oxf) 2012; 206:29-41. [PMID: 22497862 DOI: 10.1111/j.1748-1716.2012.02441.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 11/16/2011] [Accepted: 03/26/2012] [Indexed: 11/30/2022]
Abstract
AIM Myocardial stretching is an arrhythmogenic factor. Optical techniques and mechanical uncouplers are used to study the mechanoelectric feedback. The aim of this study is to determine whether the mechanical uncouplers 2,3-butanedione monoxime and Blebbistatin hinder or modify the electrophysiological effects of acute mechanical stretch. METHODS The ventricular fibrillation (VF) modifications induced by acute mechanical stretch were studied in 27 Langendorff-perfused rabbit hearts using epicardial multiple electrodes and mapping techniques under control conditions (n = 9) and during the perfusion of 2,3-butanedione monoxime (15 mM) (n = 9) or Blebbistatin (10 μm) (n = 9). RESULTS In the control series, myocardial stretch increased the complexity of the activation maps and the dominant frequency (DF) of VF from 13.1 ± 2.0 Hz to 19.1 ± 3.1 Hz (P < 0.001, 46% increment). At baseline, the activation maps showed less complexity in both the 2,3-butanedione monoxime and Blebbistatin series, and the DF was lower in the 2,3-butanedione monoxime series (11.4 ± 1.2 Hz; P < 0.05). The accelerating effect of mechanical stretch was abolished under 2,3-butanedione monoxime (maximum DF = 11.7 ± 2.4 Hz, 5% increment, ns vs baseline, P < 0.0001 vs. control series) and reduced under Blebbistatin (maximum DF = 12.9 ± 0.7 Hz, 8% increment, P < 0.01 vs. baseline, P < 0.0001 vs. control series). The variations in complexity of the activation maps under stretch were not significant in the 2,3-butanedione monoxime series and were significantly attenuated under Blebbistatin. CONCLUSION The accelerating effect and increased complexity of myocardial activation during VF induced by acute mechanical stretch are abolished under the action of 2,3-butanedione monoxime and reduced under the action of Blebbistatin.
Collapse
Affiliation(s)
- L. Brines
- Department of Medicine; Valencia University, Estudi General; Valencia; Spain
| | - L. Such-Miquel
- Department of Physiotherapy; Valencia University, Estudi General; Valencia; Spain
| | - D. Gallego
- Department of Physiology; Valencia University, Estudi General; Valencia; Spain
| | - I. Trapero
- Department of Infirmary; Valencia University, Estudi General; Valencia; Spain
| | - I. del Canto
- Department of Medicine; Valencia University, Estudi General; Valencia; Spain
| | - M. Zarzoso
- Department of Physiology; Valencia University, Estudi General; Valencia; Spain
| | - C. Soler
- Department of Physiology; Valencia University, Estudi General; Valencia; Spain
| | - F. Pelechano
- Department of Medicine; Valencia University, Estudi General; Valencia; Spain
| | - J. Cánoves
- Service of Cardiology; Valencia University Clinic Hospital; INCLIVA, Valencia; Spain
| | - A. Alberola
- Department of Physiology; Valencia University, Estudi General; Valencia; Spain
| | - L. Such
- Department of Physiology; Valencia University, Estudi General; Valencia; Spain
| | | |
Collapse
|
36
|
Caldiz CI, Díaz RG, Nolly MB, Chiappe de Cingolani GE, Ennis IL, Cingolani HE, Pérez NG. Mineralocorticoid receptor activation is crucial in the signalling pathway leading to the Anrep effect. J Physiol 2012; 589:6051-61. [PMID: 22174146 DOI: 10.1113/jphysiol.2011.218750] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The increase in myocardial reactive oxygen species after epidermal growth factor receptor transactivation is a crucial step in the autocrine/paracrine angiotensin II/endothelin receptor activation leading to the slow force response to stretch (SFR). Since experimental evidence suggests a link between angiotensin II or its AT1 receptor and the mineralocorticoid receptor (MR), and MR transactivates the epidermal growth factor receptor, we thought to determine whether MR activation participates in the SFR development in rat myocardium. We show here that MR activation is necessary to promote reactive oxygen species formation by a physiological concentration of angiotensin II (1 nmol l(-1)), since an increase in superoxide anion formation of ~50% of basal was suppressed by blocking MR with spironolactone or eplerenone. This effect was also suppressed by blocking AT1, endothelin (type A) or epidermal growth factor receptors, by inhibiting NADPH oxydase or by targeting mitochondria, and was unaffected by glucocorticoid receptor inhibition. All interventions except AT1 receptor blockade blunted the increase in superoxide anion promoted by an equipotent dose of endothelin-1 (1 nmol l(-1)) confirming that endothelin receptors activation is downstream of AT1. Similarly, an increase in superoxide anion promoted by an equipotent dose of aldosterone (10 nmol l(-1)) was blocked by spironolactone or eplerenone, by preventing epidermal growth factor receptor transactivation, but not by inhibiting glucocorticoid receptors or protein synthesis, suggesting non-genomic MR effects. Combination of aldosterone plus endothelin-1 did not increase superoxide anion formation more than each agonist separately. We found that aldosterone increased phosphorylation of the redox-sensitive kinases ERK1/2-p90RSK and the NHE-1, effects that were eliminated by eplerenone or by preventing epidermal growth factor receptor transactivation. Finally, we provide evidence that the SFR is suppressed by MR blockade, by preventing epidermal growth factor receptor transactivation or by scavenging reactive oxygen species, but it is unaffected by glucocorticoid receptor blockade or protein synthesis inhibition. Our results suggest that MR activation is a necessary step in the stretch-triggered reactive oxygen species-mediated activation of redox-sensitive kinases upstream NHE-1.
Collapse
Affiliation(s)
- Claudia I Caldiz
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | | | | | | | | | | | | |
Collapse
|
37
|
Perjés Á, Kubin A, Kónyi A, Szabados S, Cziráki A, Skoumal R, Ruskoaho H, Szokodi I. Physiological regulation of cardiac contractility by endogenous reactive oxygen species. Acta Physiol (Oxf) 2012; 205:26-40. [PMID: 22463609 DOI: 10.1111/j.1748-1716.2012.02391.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Increased production of reactive oxygen species (ROS) has been linked to the pathogenesis of congestive heart failure. However, emerging evidence suggests the involvement of ROS in the regulation of various physiological cellular processes in the myocardium. In this review, we summarize the latest findings regarding the role of ROS in the acute regulation of cardiac contractility. We discuss ROS-dependent modulation of the inotropic responses to G protein-coupled receptor agonists (e.g. β-adrenergic receptor agonists and endothelin-1), the potential cellular sources of ROS (e.g. NAD(P)H oxidases and mitochondria) and the proposed end-targets and signalling pathways by which ROS affect contractility. Accumulating new data supports the fundamental role of endogenously generated ROS to regulate cardiac function under physiological conditions.
Collapse
Affiliation(s)
| | - A.M. Kubin
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - A. Kónyi
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - S. Szabados
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - A. Cziráki
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - R. Skoumal
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - H. Ruskoaho
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - I. Szokodi
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| |
Collapse
|
38
|
Perjés Á, Kubin A, Kónyi A, Szabados S, Cziráki A, Skoumal R, Ruskoaho H, Szokodi I. Physiological regulation of cardiac contractility by endogenous reactive oxygen species. Acta Physiol (Oxf) 2012. [DOI: 10.1111/j.1748-1716.2011.02391.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | - A.M. Kubin
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - A. Kónyi
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - S. Szabados
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - A. Cziráki
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - R. Skoumal
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - H. Ruskoaho
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - I. Szokodi
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| |
Collapse
|
39
|
Pérez NG, Nolly MB, Roldan MC, Villa-Abrille MC, Cingolani E, Portiansky EL, Álvarez BV, Ennis IL, Cingolani HE. Silencing of NHE-1 blunts the slow force response to myocardial stretch. J Appl Physiol (1985) 2011; 111:874-80. [DOI: 10.1152/japplphysiol.01344.2010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Myocardial stretch induces a biphasic force response: a first abrupt increase followed by a slow force response (SFR), believed to be the in vitro manifestation of the Anrep effect. The SFR is due to an increase in Ca2+ transient of unclear mechanism. We proposed that Na+/H+ exchanger (NHE-1) activation is a key factor in determining the contractile response, but recent reports challenged our findings. We aimed to specifically test the role of the NHE-1 in the SFR. To this purpose small hairpin interference RNA capable of mediating specific NHE-1 knockdown was incorporated into a lentiviral vector (l-shNHE1) and injected into the left ventricular wall of Wistar rats. Injection of a lentiviral vector expressing a nonsilencing sequence (scramble) served as control. Myocardial NHE-1 protein expression and function (the latter evaluated by the recovery of pHi after an acidic load and the SFR) were evaluated. Animals transduced with l-shNHE1 showed reduced NHE-1 expression (45 ± 8% of controls; P < 0.05), and the presence of the lentivirus in the left ventricular myocardium, far from the site of injection, was evidenced by confocal microscopy. These findings correlated with depressed basal pHi recovery after acidosis [maxdpHi/d t 0.055 ± 0.008 (scramble) vs. 0.009 ± 0.004 (l-shNHE1) pH units/min, P < 0.05], leftward shift of the relationship between JH+ (H+ efflux corrected by the intrinsic buffer capacity), and abolishment of SFR (124 ± 2 vs. 101 ± 2% of rapid phase; P < 0.05) despite preserved ERK1/2 phosphorylation [247 ± 12 (stretch) and 263 ± 23 (stretch l-shNHE1) % of control; P < 0.05 vs. nonstretched control], well-known NHE-1 activators. Our results provide strong evidence to propose NHE-1 activation as key factor in determining the SFR to stretch.
Collapse
Affiliation(s)
- Néstor G. Pérez
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Mariela B. Nolly
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Mirian C. Roldan
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - María C. Villa-Abrille
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Eugenio Cingolani
- Cedars Sinai Heart Institute, Cedars Sinai Medical Center, Los Angeles, California; and
| | - Enrique L. Portiansky
- Instituto de Patología. Facultad de Cs. Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina
| | - Bernardo V. Álvarez
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Irene L. Ennis
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Horacio E. Cingolani
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| |
Collapse
|
40
|
Harvey RD, Calaghan SC. Caveolae create local signalling domains through their distinct protein content, lipid profile and morphology. J Mol Cell Cardiol 2011; 52:366-75. [PMID: 21782827 DOI: 10.1016/j.yjmcc.2011.07.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 06/21/2011] [Accepted: 07/07/2011] [Indexed: 01/02/2023]
Abstract
Compartmentation of signalling allows multiple stimuli to achieve diverse cellular responses with only a limited pool of second messengers. This spatial control of signalling is achieved, in part, by cellular structures which bring together elements of a particular cascade. One such structure is the caveola, a flask-shaped lipid raft. Caveolae are well-recognised as signalosomes, platforms for assembly of signalling complexes of receptors, effectors and their targets, which can facilitate efficient and specific cellular responses. Here we extend this simple model and present evidence to show how the protein and lipid profiles of caveolae, as well as their characteristic morphology, define their roles in creating local signalling domains in the cardiac myocyte. This article is part of a Special Issue entitled "Local Signaling in Myocytes."
Collapse
Affiliation(s)
- Robert D Harvey
- Department of Pharmacology, University of Nevada School of Medicine, Reno, NV 89557, USA
| | | |
Collapse
|
41
|
Patrick SM, White E, Shiels HA. Rainbow trout myocardium does not exhibit a slow inotropic response to stretch. J Exp Biol 2011; 214:1118-22. [DOI: 10.1242/jeb.048546] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
SUMMARY
Mammalian myocardial studies reveal a biphasic increase in the force of contraction due to stretch. The first rapid response, known as the Frank-Starling response, occurs within one heartbeat of stretch. A second positive inotropic response occurs over the minutes following the initial stretch and is known as the slow force response (SFR). The SFR has been observed in mammalian isolated whole hearts, muscle preparations and individual myocytes. We present the first direct study into the SFR in the heart of a non-mammalian vertebrate, the rainbow trout (Oncorhynchus mykiss). We stretched ventricular trabecular muscle preparations from 88% to 98% of their optimal length and individual ventricular myocytes by 7% of their slack sarcomere length (SL). Stretch caused an immediate increase in force in both preparations, indicative of the Frank-Starling response. However, we found no significant effect of prolonged stretch on the force of contraction in either the ventricular trabecular preparations or the single myocytes. This indicates that rainbow trout ventricular myocardium does not exhibit a SFR and that, in contrast to mammals, the piscine Frank-Starling response may not be associated with the SFR. We speculate that this is due to the fish myocardium modulating cardiac output via changes in stroke volume to a larger extent than heart rate.
Collapse
Affiliation(s)
- Simon M. Patrick
- Faculty of Life Sciences, University of Manchester, 46 Grafton Street, Manchester M13 9NT, UK
| | - Ed White
- Institute of Membrane and Systems Biology, and Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds LS2 9JT, UK
| | - Holly A. Shiels
- Faculty of Life Sciences, University of Manchester, 46 Grafton Street, Manchester M13 9NT, UK
| |
Collapse
|
42
|
Kohan DE, Rossi NF, Inscho EW, Pollock DM. Regulation of blood pressure and salt homeostasis by endothelin. Physiol Rev 2011; 91:1-77. [PMID: 21248162 DOI: 10.1152/physrev.00060.2009] [Citation(s) in RCA: 276] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Endothelin (ET) peptides and their receptors are intimately involved in the physiological control of systemic blood pressure and body Na homeostasis, exerting these effects through alterations in a host of circulating and local factors. Hormonal systems affected by ET include natriuretic peptides, aldosterone, catecholamines, and angiotensin. ET also directly regulates cardiac output, central and peripheral nervous system activity, renal Na and water excretion, systemic vascular resistance, and venous capacitance. ET regulation of these systems is often complex, sometimes involving opposing actions depending on which receptor isoform is activated, which cells are affected, and what other prevailing factors exist. A detailed understanding of this system is important; disordered regulation of the ET system is strongly associated with hypertension and dysregulated extracellular fluid volume homeostasis. In addition, ET receptor antagonists are being increasingly used for the treatment of a variety of diseases; while demonstrating benefit, these agents also have adverse effects on fluid retention that may substantially limit their clinical utility. This review provides a detailed analysis of how the ET system is involved in the control of blood pressure and Na homeostasis, focusing primarily on physiological regulation with some discussion of the role of the ET system in hypertension.
Collapse
Affiliation(s)
- Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
| | | | | | | |
Collapse
|
43
|
Cingolani HE, Ennis IL, Aiello EA, Pérez NG. Role of autocrine/paracrine mechanisms in response to myocardial strain. Pflugers Arch 2011; 462:29-38. [DOI: 10.1007/s00424-011-0930-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 01/19/2011] [Accepted: 01/19/2011] [Indexed: 10/18/2022]
|
44
|
Villa-Abrille MC, Caldiz CI, Ennis IL, Nolly MB, Casarini MJ, Chiappe de Cingolani GE, Cingolani HE, Pérez NG. The Anrep effect requires transactivation of the epidermal growth factor receptor. J Physiol 2010; 588:1579-90. [PMID: 20231142 DOI: 10.1113/jphysiol.2009.186619] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Myocardial stretch elicits a biphasic contractile response: the Frank-Starling mechanism followed by the slow force response (SFR) or Anrep effect. In this study we hypothesized that the SFR depends on epidermal growth factor receptor (EGFR) transactivation after the myocardial stretch-induced angiotensin II (Ang II)/endothelin (ET) release. Experiments were performed in isolated cat papillary muscles stretched from 92 to 98% of the length at which maximal twitch force was developed (L(max)). The SFR was 123 +/- 1% of the immediate rapid phase (n = 6, P < 0.05) and was blunted by preventing EGFR transactivation with the Src-kinase inhibitor PP1 (99 +/- 2%, n = 4), matrix metalloproteinase inhibitor MMPI (108 +/- 4%, n = 11), the EGFR blocker AG1478 (98 +/- 2%, n = 6) or the mitochondrial transition pore blocker clyclosporine (99 +/- 3%, n = 6). Stretch increased ERK1/2 phosphorylation by 196 +/- 17% of control (n = 7, P < 0.05), an effect that was prevented by PP1 (124 +/- 22%, n = 7) and AG1478 (131 +/- 17%, n = 4). In myocardial slices, Ang II (which enhances ET mRNA) or endothelin-1 (ET-1)-induced increase in O(2)() production (146 +/- 14%, n = 9, and 191 +/- 17%, n = 13, of control, respectively, P < 0.05) was cancelled by AG1478 (94 +/- 5%, n = 12, and 98 +/- 15%, n = 8, respectively) or PP1 (100 +/- 4%, n = 6, and 99 +/- 8%, n = 3, respectively). EGF increased O(2)() production by 149 +/- 4% of control (n = 9, P < 0.05), an effect cancelled by inhibiting NADPH oxidase with apocynin (110 +/- 6% n = 7), mKATP channels with 5-hydroxydecanoic acid (5-HD; 105 +/- 5%, n = 8), the respiratory chain with rotenone (110 +/- 7%, n = 7) or the mitochondrial permeability transition pore with cyclosporine (111 +/- 10%, n = 6). EGF increased ERK1/2 phosphorylation (136 +/- 8% of control, n = 9, P < 0.05), which was blunted by 5-HD (97 +/- 5%, n = 4), suggesting that ERK1/2 activation is downstream of mitochondrial oxidative stress. Finally, stretch increased Ser703 Na(+)/H(+) exchanger-1 (NHE-1) phosphorylation by 172 +/- 24% of control (n = 4, P < 0.05), an effect that was cancelled by AG1478 (94 +/- 17%, n = 4). In conclusion, our data show for the first time that EGFR transactivation is crucial in the chain of events leading to the Anrep effect.
Collapse
Affiliation(s)
- María C Villa-Abrille
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, UNLP, 60 y 120 (1900) La Plata, Argentina
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Chorro FJ, Trapero I, Such-Miquel L, Pelechano F, Mainar L, Cánoves J, Tormos Á, Alberola A, Hove-Madsen L, Cinca J, Such L. Pharmacological modifications of the stretch-induced effects on ventricular fibrillation in perfused rabbit hearts. Am J Physiol Heart Circ Physiol 2009; 297:H1860-9. [DOI: 10.1152/ajpheart.00144.2009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Stretch induces modifications in myocardial electrical and mechanical activity. Besides the effects of substances that block the stretch-activated channels, other substances could modulate the effects of stretch through different mechanisms that affect Ca2+ handling by myocytes. Thirty-six Langendorff-perfused rabbit hearts were used to analyze the effects of the Na+/Ca2+ exchanger blocker KB-R7943, propranolol, and the adenosine A2 receptor antagonist SCH-58261 on the acceleration of ventricular fibrillation (VF) produced by acute myocardial stretching. VF recordings were obtained with two epicardial multiple electrodes before, during, and after local stretching in four experimental series: control ( n = 9), KB-R7943 (1 μM, n = 9), propranolol (1 μM, n = 9), and SCH-58261 (1 μM, n = 9). Both the Na+/Ca2+ exchanger blocker KB-R7943 and propranolol induced a significant reduction ( P < 0.001 and P < 0.05, respectively) in the dominant frequency increments produced by stretching with respect to the control and SCH-58261 series (control = 49.9%, SCH-58261 = 52.1%, KB-R7943 = 9.5%, and propranolol = 12.5%). The median of the activation intervals, the functional refractory period, and the wavelength of the activation process during VF decreased significantly under stretch in the control and SCH-58261 series, whereas no significant variations were observed in the propranolol and KB-R7943 series, with the exception of a slight but significant decrease in the median of the fibrillation intervals in the KB-R7943 series. KB-R7943 and propranolol induced a significant reduction in the activation maps complexity increment produced by stretch with respect to the control and SCH-58261 series. In conclusion, the electrophysiological effects responsible for stretch-induced VF acceleration in the rabbit heart are reduced by the Na+/Ca2+ exchanger blocker KB-R7943 and by propranolol but not by the adenosine A2 receptor antagonist SCH-58261.
Collapse
Affiliation(s)
- Francisco J. Chorro
- Service of Cardiology, Valencia University Clinic Hospital, Valencia
- Departments of 2Medicine,
| | | | | | | | - Luis Mainar
- Service of Cardiology, Valencia University Clinic Hospital, Valencia
| | - Joaquín Cánoves
- Service of Cardiology, Valencia University Clinic Hospital, Valencia
| | - Álvaro Tormos
- Department of Electronics, Valencia Polytechnic University, Valencia; and
| | | | - Leif Hove-Madsen
- Cardiology Department, Santa Creu i Sant Pau Hospital, Barcelona, Spain
| | - Juan Cinca
- Cardiology Department, Santa Creu i Sant Pau Hospital, Barcelona, Spain
| | - Luis Such
- Physiology, Valencia University, Valencia
| |
Collapse
|
46
|
Zhang YH, Dingle L, Hall R, Casadei B. The role of nitric oxide and reactive oxygen species in the positive inotropic response to mechanical stretch in the mammalian myocardium. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:811-7. [PMID: 19361482 PMCID: PMC2791851 DOI: 10.1016/j.bbabio.2009.03.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 03/28/2009] [Accepted: 03/31/2009] [Indexed: 11/13/2022]
Abstract
The endothelial nitric oxide synthase (eNOS) has been implicated in the rapid (Frank–Starling) and slow (Anrep) cardiac response to stretch. Our work and that of others have demonstrated that a neuronal nitric oxide synthase (nNOS) localized to the myocardium plays an important role in the regulation of cardiac function and calcium handling. However, the effect of nNOS on the myocardial response to stretch has yet to be investigated. Recent evidence suggests that the stretch-induced release of angiotensin II (Ang II) and endothelin 1 (ET-1) stimulates myocardial superoxide production from NADPH oxidases which, in turn, contributes to the Anrep effect. nNOS has also been shown to regulate the production of myocardial superoxide, suggesting that this isoform may influence the cardiac response to stretch or ET-1 by altering the NO-redox balance in the myocardium. Here we show that the increase in left ventricular (LV) myocyte shortening in response to the application of ET-1 (10 nM, 5 min) did not differ between nNOS−/− mice and their wild type littermates (nNOS+/+). Pre-incubating LV myocytes with the NADPH oxidase inhibitor, apocynin (100 μM, 30 min), reduced cell shortening in nNOS−/− myocytes only but prevented the positive inotropic effects of ET-1 in both groups. Superoxide production (O2−) was enhanced in nNOS−/− myocytes compared to nNOS+/+; however, this difference was abolished by pre-incubation with apocynin. There was no detectable increase in O2− production in ET-1 pre-treated LV myocytes. Inhibition of protein kinase C (chelerythrine, 1 μM) did not affect cell shortening in either group, however, protein kinase A inhibitor, PKI (2 μM), significantly reduced the positive inotropic effects of ET-1 in both nNOS+/+ and nNOS−/− myocytes. Taken together, our findings show that the positive inotropic effect of ET-1 in murine LV myocytes is independent of nNOS but requires NADPH oxidases and protein kinase A (PKA)-dependent signaling. These results may further our understanding of the signaling pathways involved in the myocardial inotropic response to stretch.
Collapse
Affiliation(s)
- Yin Hua Zhang
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
| | | | | | | |
Collapse
|
47
|
Abstract
The family of mammalian bicarbonate transport proteins are involved in a wide-range of physiological processes. The importance of bicarbonate transport follows from the biochemistry of HCO(3)(-) itself. Bicarbonate is the waste product of mitochondrial respiration. HCO(3)(-) undergoes pH-dependent conversion into CO(2) and in doing so converts from a membrane impermeant anion into a gas that can diffuse across membranes. The CO(2)-HCO(3)(-) equilibrium forms the most important pH buffering system of our bodies. Bicarbonate transport proteins facilitate the movement of membrane-impermeant HCO(3)(-) across membranes to accelerate disposal of waste CO(2), control cellular and whole-body pH, and to regulate fluid movement and acid/base secretion. Defects of bicarbonate transport proteins manifest in diseases of most organ systems. Fourteen gene products facilitate mammalian bicarbonate transport, whose physiology and pathophysiology is discussed in the present review.
Collapse
|
48
|
Saygili E, Rana OR, Meyer C, Gemein C, Andrzejewski MG, Ludwig A, Weber C, Schotten U, Krüttgen A, Weis J, Schwinger RHG, Mischke K, Rassaf T, Kelm M, Schauerte P. The angiotensin–calcineurin–NFAT pathway mediates stretch-induced up-regulation of matrix metalloproteinases-2/-9 in atrial myocytes. Basic Res Cardiol 2009; 104:435-48. [DOI: 10.1007/s00395-008-0772-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Accepted: 11/27/2008] [Indexed: 11/25/2022]
|
49
|
Prasad V, Bodi I, Meyer JW, Wang Y, Ashraf M, Engle SJ, Doetschman T, Sisco K, Nieman ML, Miller ML, Lorenz JN, Shull GE. Impaired cardiac contractility in mice lacking both the AE3 Cl-/HCO3- exchanger and the NKCC1 Na+-K+-2Cl- cotransporter: effects on Ca2+ handling and protein phosphatases. J Biol Chem 2008; 283:31303-14. [PMID: 18779325 PMCID: PMC2581574 DOI: 10.1074/jbc.m803706200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 08/27/2008] [Indexed: 12/27/2022] Open
Abstract
To analyze the cardiac functions of AE3, we disrupted its gene (Slc4a3) in mice. Cl(-)/HCO3(-) exchange coupled with Na+-dependent acid extrusion can mediate pH-neutral Na+ uptake, potentially affecting Ca2+ handling via effects on Na+/Ca2+ exchange. AE3 null mice appeared normal, however, and AE3 ablation had no effect on ischemia-reperfusion injury in isolated hearts or cardiac performance in vivo. The NKCC1 Na+-K+-2Cl(-) cotransporter also mediates Na+ uptake, and loss of NKCC1 alone does not impair contractility. To further stress the AE3-deficient myocardium, we combined the AE3 and NKCC1 knock-outs. Double knock-outs had impaired contraction and relaxation both in vivo and in isolated ventricular myocytes. Ca2+ transients revealed an apparent increase in Ca2+ clearance in double null cells. This was unlikely to result from increased Ca2+ sequestration, since the ratio of phosphorylated phospholamban to total phospholamban was sharply reduced in all three mutant hearts. Instead, Na+/Ca2+ exchanger activity was found to be enhanced in double null cells. Systolic Ca2+ was unaltered, however, suggesting more direct effects on the contractile apparatus of double null myocytes. Expression of the catalytic subunit of protein phosphatase 1 was increased in all mutant hearts. There was also a dramatic reversal, between single null and double null hearts, in the carboxymethylation and localization to the myofibrillar fraction, of the catalytic subunit of protein phosphatase 2A, which corresponded to the loss of normal contractility in double null hearts. These data show that AE3 and NKCC1 affect Ca2+ handling, PLN regulation, and expression and localization of major cardiac phosphatases and that their combined loss impairs cardiac function.
Collapse
Affiliation(s)
- Vikram Prasad
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0524, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Stanbouly S, Kirshenbaum LA, Jones DL, Karmazyn M. Sodium Hydrogen Exchange 1 (NHE-1) Regulates Connexin 43 Expression in Cardiomyocytes via Reverse Mode Sodium Calcium Exchange and c-Jun NH2-Terminal Kinase-Dependent Pathways. J Pharmacol Exp Ther 2008; 327:105-13. [DOI: 10.1124/jpet.108.140228] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|