1
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Shi X, Jiang X, Chen C, Zhang Y, Sun X. The interconnections between the microtubules and mitochondrial networks in cardiocerebrovascular diseases: Implications for therapy. Pharmacol Res 2022; 184:106452. [PMID: 36116706 DOI: 10.1016/j.phrs.2022.106452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/13/2022] [Accepted: 09/13/2022] [Indexed: 10/14/2022]
Abstract
Microtubules, a highly dynamic cytoskeleton, participate in many cellular activities including mechanical support, organelles interactions, and intracellular trafficking. Microtubule organization can be regulated by modification of tubulin subunits, microtubule-associated proteins (MAPs) or agents modulating microtubule assembly. Increasing studies demonstrate that microtubule disorganization correlates with various cardiocerebrovascular diseases including heart failure and ischemic stroke. Microtubules also mediate intracellular transport as well as intercellular transfer of mitochondria, a power house in cells which produce ATP for various physiological activities such as cardiac mechanical function. It is known to all that both microtubules and mitochondria participate in the progression of cancer and Parkinson's disease. However, the interconnections between the microtubules and mitochondrial networks in cardiocerebrovascular diseases remain unclear. In this paper, we will focus on the roles of microtubules in cardiocerebrovascular diseases, and discuss the interplay of mitochondria and microtubules in disease development and treatment. Elucidation of these issues might provide significant diagnostic value as well as potential targets for cardiocerebrovascular diseases.
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Affiliation(s)
- Xingjuan Shi
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China.
| | - Xuan Jiang
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Congwei Chen
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Yu Zhang
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Xiaoou Sun
- Institute of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, China.
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2
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Mostafavi S, Balafkan N, Pettersen IKN, Nido GS, Siller R, Tzoulis C, Sullivan GJ, Bindoff LA. Distinct Mitochondrial Remodeling During Mesoderm Differentiation in a Human-Based Stem Cell Model. Front Cell Dev Biol 2021; 9:744777. [PMID: 34722525 PMCID: PMC8553110 DOI: 10.3389/fcell.2021.744777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/21/2021] [Indexed: 12/17/2022] Open
Abstract
Given the considerable interest in using stem cells for modeling and treating disease, it is essential to understand what regulates self-renewal and differentiation. Remodeling of mitochondria and metabolism, with the shift from glycolysis to oxidative phosphorylation (OXPHOS), plays a fundamental role in maintaining pluripotency and stem cell fate. It has been suggested that the metabolic “switch” from glycolysis to OXPHOS is germ layer-specific as glycolysis remains active during early ectoderm commitment but is downregulated during the transition to mesoderm and endoderm lineages. How mitochondria adapt during these metabolic changes and whether mitochondria remodeling is tissue specific remain unclear. Here, we address the question of mitochondrial adaptation by examining the differentiation of human pluripotent stem cells to cardiac progenitors and further to differentiated mesodermal derivatives, including functional cardiomyocytes. In contrast to recent findings in neuronal differentiation, we found that mitochondrial content decreases continuously during mesoderm differentiation, despite increased mitochondrial activity and higher levels of ATP-linked respiration. Thus, our work highlights similarities in mitochondrial remodeling during the transition from pluripotent to multipotent state in ectodermal and mesodermal lineages, while at the same time demonstrating cell-lineage-specific adaptations upon further differentiation. Our results improve the understanding of how mitochondrial remodeling and the metabolism interact during mesoderm differentiation and show that it is erroneous to assume that increased OXPHOS activity during differentiation requires a simultaneous expansion of mitochondrial content.
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Affiliation(s)
- Sepideh Mostafavi
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Novin Balafkan
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.,Norwegian Centre for Mental Disorders Research (NORMENT)-Centre of Excellence, Haukeland University Hospital, Bergen, Norway
| | | | - Gonzalo S Nido
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Richard Siller
- Stem Cell Epigenetics Laboratory, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Charalampos Tzoulis
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Gareth J Sullivan
- Stem Cell Epigenetics Laboratory, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Norwegian Center for Stem Cell Research, Oslo University Hospital and the University of Oslo, Oslo, Norway.,Institute of Immunology, Oslo University Hospital, Oslo, Norway.,Hybrid Technology Hub-Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Pediatric Research, Oslo University Hospital, Oslo, Norway
| | - Laurence A Bindoff
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Department of Neurology, Haukeland University Hospital, Bergen, Norway
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3
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Kassab S, Albalawi Z, Daghistani H, Kitmitto A. Mitochondrial Arrest on the Microtubule Highway-A Feature of Heart Failure and Diabetic Cardiomyopathy? Front Cardiovasc Med 2021; 8:689101. [PMID: 34277734 PMCID: PMC8282893 DOI: 10.3389/fcvm.2021.689101] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/08/2021] [Indexed: 01/16/2023] Open
Abstract
A pathophysiological consequence of both type 1 and 2 diabetes is remodelling of the myocardium leading to the loss of left ventricular pump function and ultimately heart failure (HF). Abnormal cardiac bioenergetics associated with mitochondrial dysfunction occurs in the early stages of HF. Key factors influencing mitochondrial function are the shape, size and organisation of mitochondria within cardiomyocytes, with reports identifying small, fragmented mitochondria in the myocardium of diabetic patients. Cardiac mitochondria are now known to be dynamic organelles (with various functions beyond energy production); however, the mechanisms that underpin their dynamism are complex and links to motility are yet to be fully understood, particularly within the context of HF. This review will consider how the outer mitochondrial membrane protein Miro1 (Rhot1) mediates mitochondrial movement along microtubules via crosstalk with kinesin motors and explore the evidence for molecular level changes in the setting of diabetic cardiomyopathy. As HF and diabetes are recognised inflammatory conditions, with reports of enhanced activation of the NLRP3 inflammasome, we will also consider evidence linking microtubule organisation, inflammation and the association to mitochondrial motility. Diabetes is a global pandemic but with limited treatment options for diabetic cardiomyopathy, therefore we also discuss potential therapeutic approaches to target the mitochondrial-microtubule-inflammatory axis.
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Affiliation(s)
- Sarah Kassab
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Zainab Albalawi
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Hussam Daghistani
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Ashraf Kitmitto
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
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4
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Orini M, Taggart P, Bhuva A, Roberts N, Di Salvo C, Yates M, Badiani S, Van Duijvenboden S, Lloyd G, Smith A, Lambiase PD. Direct in vivo assessment of global and regional mechanoelectric feedback in the intact human heart. Heart Rhythm 2021; 18:1406-1413. [PMID: 33932588 PMCID: PMC8353585 DOI: 10.1016/j.hrthm.2021.04.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023]
Abstract
Background Inhomogeneity of ventricular contraction is associated with sudden cardiac death, but the underlying mechanisms are unclear. Alterations in cardiac contraction impact electrophysiological parameters through mechanoelectric feedback. This has been shown to promote arrhythmias in experimental studies, but its effect in the in vivo human heart is unclear. Objective The purpose of this study was to quantify the impact of regional myocardial deformation provoked by a sudden increase in ventricular loading (aortic occlusion) on human cardiac electrophysiology. Methods In 10 patients undergoing open heart cardiac surgery, left ventricular (LV) afterload was modified by transient aortic occlusion. Simultaneous assessment of whole-heart electrophysiology and LV deformation was performed using an epicardial sock (240 electrodes) and speckle-tracking transesophageal echocardiography. Parameters were matched to 6 American Heart Association LV model segments. The association between changes in regional myocardial segment length and activation-recovery interval (ARI; a conventional surrogate for action potential duration) was studied using mixed-effect models. Results Increased ventricular loading reduced longitudinal shortening (P = .01) and shortened ARI (P = .02), but changes were heterogeneous between cardiac segments. Increased regional longitudinal shortening was associated with ARI shortening (effect size 0.20 [0.01–0.38] ms/%; P = .04) and increased local ARI dispersion (effect size –0.13 [–0.23 to –0.03] ms/%; P = .04). At the whole organ level, increased mechanical dispersion translated into increased dispersion of repolarization (correlation coefficient r = 0.81; P = .01). Conclusion Mechanoelectric feedback can establish a potentially proarrhythmic substrate in the human heart and should be considered to advance our understanding and prevention of cardiac arrhythmias.
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Affiliation(s)
- Michele Orini
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Peter Taggart
- Institute of Cardiovascular Science, University College London, London, United Kingdom.
| | - Anish Bhuva
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Neil Roberts
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Carmelo Di Salvo
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Martin Yates
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Sveeta Badiani
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | | | - Guy Lloyd
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Andrew Smith
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Pier D Lambiase
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
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5
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Quinn TA, Kohl P. Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm. Physiol Rev 2020; 101:37-92. [PMID: 32380895 DOI: 10.1152/physrev.00036.2019] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.
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Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Peter Kohl
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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6
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Fernández-Morales JC, Morad M. Regulation of Ca 2+ signaling by acute hypoxia and acidosis in rat neonatal cardiomyocytes. J Mol Cell Cardiol 2017; 114:58-71. [PMID: 29032102 DOI: 10.1016/j.yjmcc.2017.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/20/2017] [Accepted: 10/08/2017] [Indexed: 11/25/2022]
Abstract
Ischemic heart disease is an arrhythmogenic condition, accompanied by hypoxia, acidosis, and impaired Ca2+ signaling. Here we report on effects of acute hypoxia and acidification in rat neonatal cardiomyocytes cultures. RESULTS Two populations of neonatal cardiomyocyte were identified based on inactivation kinetics of L-type ICa: rapidly-inactivating ICa (τ~20ms) myocytes (prevalent in 3-4-day cultures), and slow-inactivating ICa (τ≥40ms) myocytes (dominant in 7-day cultures). Acute hypoxia (pO2<5mmHg for 50-100s) suppressed ICa reversibly in both cell-types to different extent and with different kinetics. This disparity disappeared when Ba2+ was the channel charge carrier, or when the intracellular Ca2+ buffering capacity was increased by dialysis of high concentrations of EGTA and BAPTA, suggesting critical role for calcium-dependent inactivation. Suppressive effect of acute acidosis on ICa (~40%, pH6.7), on the other hand, was not cell-type dependent. Isoproterenol enhanced ICa in both cell-types, but protected only against suppressive effects of acidosis and not hypoxia. Hypoxia and acidosis suppressed global Ca2+ transients by ~20%, but suppression was larger, ~35%, at the RyR2 microdomains, using GCaMP6-FKBP targeted probe. Hypoxia and acidosis also suppressed mitochondrial Ca2+ uptake by 40% and 10%, respectively, using mitochondrial targeted Ca2+ biosensor (mito-GCaMP6). CONCLUSION Our studies suggest that acute hypoxia suppresses ICa in rapidly inactivating cell population by a mechanism involving Ca2+-dependent inactivation, while compromised mitochondrial Ca2+ uptake seems also to contribute to ICa suppression in slowly inactivating cell population. Proximity of cellular Ca2+ pools to sarcolemmal Ca2+ channels may contribute to the variability of inactivation kinetics of ICa in the two cell populations, while acidosis suppression of ICa appears mediated by proton-induced block of the calcium channel.
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Affiliation(s)
| | - Martin Morad
- Cardiac Signaling Center of MUSC, USC and Clemson, Charleston, SC, USA; Department of Pharmacology, Georgetown University Medical Center, Washington, DC, USA.
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7
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Altered Mitochondrial Metabolism and Mechanosensation in the Failing Heart: Focus on Intracellular Calcium Signaling. Int J Mol Sci 2017; 18:ijms18071487. [PMID: 28698526 PMCID: PMC5535977 DOI: 10.3390/ijms18071487] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 06/28/2017] [Accepted: 07/04/2017] [Indexed: 12/26/2022] Open
Abstract
The heart consists of millions of cells, namely cardiomyocytes, which are highly organized in terms of structure and function, at both macroscale and microscale levels. Such meticulous organization is imperative for assuring the physiological pump-function of the heart. One of the key players for the electrical and mechanical synchronization and contraction is the calcium ion via the well-known calcium-induced calcium release process. In cardiovascular diseases, the structural organization is lost, resulting in morphological, electrical, and metabolic remodeling owing the imbalance of the calcium handling and promoting heart failure and arrhythmias. Recently, attention has been focused on the role of mitochondria, which seem to jeopardize these events by misbalancing the calcium processes. In this review, we highlight our recent findings, especially the role of mitochondria (dys)function in failing cardiomyocytes with respect to the calcium machinery.
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8
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Mechano-sensitivity of mitochondrial function in mouse cardiac myocytes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:315-322. [PMID: 28668597 DOI: 10.1016/j.pbiomolbio.2017.05.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 10/19/2022]
Abstract
Mitochondria are an important source of reactive oxygen species (ROS). Although it has been reported that myocardial stretch increases cellular ROS production by activating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2), referred to as X-ROS signalling, the involvement of mitochondria in X-ROS is not clear. Mitochondria are organelles that generate adenosine triphosphate (ATP) for cellular energy needs, which are mechanical-load-dependent. Therefore, it would not be surprising if these organelles had mechano-sensitive functions associated with stretch-induced ROS production. In the present study, we investigated the relation between X-ROS and mitochondrial stretch-sensitive responses in isolated mouse cardiac myocytes. The cells were subjected to 10% axial stretch using computer-controlled, piezo-manipulated carbon fibres attached to both cell ends. Cellular ROS production and mitochondrial membrane potential (Δψm) were assessed optically by confocal microscopy. The axial stretch increased ROS production and hyperpolarised Δψm. Treatment with a mitochondrial metabolic uncoupler, carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP), at 0.5 μM did not suppress stretch-induced ROS production, whereas treatment with a respiratory Complex III inhibitor, antimycin A (5 μM), blunted the response. Although NOX inhibition by apocynin abrogated the stretch-induced ROS production, it did not suppress stretch-induced hyperpolarisation of Δψm. These results suggest that stretch causes activation of the respiratory chain to hyperpolarise Δψm, followed by NOX activation, which increases ROS production.
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9
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Miragoli M, Cabassi A. Mitochondrial Mechanosensor Microdomains in Cardiovascular Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:247-264. [PMID: 28551791 DOI: 10.1007/978-3-319-55330-6_13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The cardiomyocytes populating the 'working myocardium' are highly organized and such organization ranges from macroscale (e.g. the geometrical rod shape) to microscale (dyad/t-tubules) domains. This meticulous level of organization is imperative for assuring the normal and physiological pump-function of the heart. In the pathological cardiac tissue, the domains-related architecture is partially lost, resulting in morphological, electrical and metabolic remodeling and promoting cardiovascular diseases including heart failure and arrhythmias. Indeed, arrhythmogenesis during heart failure is a major clinical problem. Arrhythmias have been extensively studied from an electrical etiology, but only recently, physiologists and scientists have focused their attention on cellular and subcellular mechanosensors. We and others have investigated whether the nanoscale mechanosensitive properties of cardiomyocytes from failing hearts have a bearing upon the initiation of abnormal electrical activity. This chapter highlights the recent findings in the field, especially the role of mitochondria function and alignment in failing cardiomyocytes interrogated via nanomechanical stimuli.
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Affiliation(s)
- Michele Miragoli
- Department of Medicine and Surgery, University of Parma, Parma, 43124, Italy. .,Humanitas Clinical and Research Center, Rozzano, MI, Italy.
| | - Aderville Cabassi
- Department of Medicine and Surgery, University of Parma, Parma, 43124, Italy
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10
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Abstract
Mechanical forces will have been omnipresent since the origin of life, and living organisms have evolved mechanisms to sense, interpret, and respond to mechanical stimuli. The cardiovascular system in general, and the heart in particular, is exposed to constantly changing mechanical signals, including stretch, compression, bending, and shear. The heart adjusts its performance to the mechanical environment, modifying electrical, mechanical, metabolic, and structural properties over a range of time scales. Many of the underlying regulatory processes are encoded intracardially and are, thus, maintained even in heart transplant recipients. Although mechanosensitivity of heart rhythm has been described in the medical literature for over a century, its molecular mechanisms are incompletely understood. Thanks to modern biophysical and molecular technologies, the roles of mechanical forces in cardiac biology are being explored in more detail, and detailed mechanisms of mechanotransduction have started to emerge. Mechano-gated ion channels are cardiac mechanoreceptors. They give rise to mechano-electric feedback, thought to contribute to normal function, disease development, and, potentially, therapeutic interventions. In this review, we focus on acute mechanical effects on cardiac electrophysiology, explore molecular candidates underlying observed responses, and discuss their pharmaceutical regulation. From this, we identify open research questions and highlight emerging technologies that may help in addressing them.
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Affiliation(s)
- Rémi Peyronnet
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (R.P., P.K.); Departments of Developmental Biology and Internal Medicine, Center for Cardiovascular Research, Washington University School of Medicine, St. Louis, MO (J.M.N.); Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Freiburg, Germany (R.P., P.K.)
| | - Jeanne M Nerbonne
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (R.P., P.K.); Departments of Developmental Biology and Internal Medicine, Center for Cardiovascular Research, Washington University School of Medicine, St. Louis, MO (J.M.N.); Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Freiburg, Germany (R.P., P.K.)
| | - Peter Kohl
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (R.P., P.K.); Departments of Developmental Biology and Internal Medicine, Center for Cardiovascular Research, Washington University School of Medicine, St. Louis, MO (J.M.N.); Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Freiburg, Germany (R.P., P.K.).
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11
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Choi Y, Park JE, Jeong JS, Park JK, Kim J, Jeon S. Sound Waves Induce Neural Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells via Ryanodine Receptor-Induced Calcium Release and Pyk2 Activation. Appl Biochem Biotechnol 2016; 180:682-694. [DOI: 10.1007/s12010-016-2124-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/06/2016] [Indexed: 02/05/2023]
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12
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Scheitlin CG, Julian JA, Shanmughapriya S, Madesh M, Tsoukias NM, Alevriadou BR. Endothelial mitochondria regulate the intracellular Ca2+ response to fluid shear stress. Am J Physiol Cell Physiol 2016; 310:C479-90. [PMID: 26739489 DOI: 10.1152/ajpcell.00171.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 01/04/2016] [Indexed: 02/04/2023]
Abstract
Shear stress is known to stimulate an intracellular free calcium concentration ([Ca(2+)]i) response in vascular endothelial cells (ECs). [Ca(2+)]i is a key second messenger for signaling that leads to vasodilation and EC survival. Although it is accepted that the shear-induced [Ca(2+)]i response is, in part, due to Ca(2+) release from the endoplasmic reticulum (ER), the role of mitochondria (second largest Ca(2+) store) is unknown. We hypothesized that the mitochondria play a role in regulating [Ca(2+)]i in sheared ECs. Cultured ECs, loaded with a Ca(2+)-sensitive fluorophore, were exposed to physiological levels of shear stress. Shear stress elicited [Ca(2+)]i transients in a percentage of cells with a fraction of them displaying oscillations. Peak magnitudes, percentage of oscillating ECs, and oscillation frequencies depended on the shear level. [Ca(2+)]i transients/oscillations were present when experiments were conducted in Ca(2+)-free solution (plus lanthanum) but absent when ECs were treated with a phospholipase C inhibitor, suggesting that the ER inositol 1,4,5-trisphosphate receptor is responsible for the [Ca(2+)]i response. Either a mitochondrial uncoupler or an electron transport chain inhibitor, but not a mitochondrial ATP synthase inhibitor, prevented the occurrence of transients and especially inhibited the oscillations. Knockdown of the mitochondrial Ca(2+) uniporter also inhibited the shear-induced [Ca(2+)]i transients/oscillations compared with controls. Hence, EC mitochondria, through Ca(2+) uptake/release, regulate the temporal profile of shear-induced ER Ca(2+) release. [Ca(2+)]i oscillation frequencies detected were within the range for activation of mechanoresponsive kinases and transcription factors, suggesting that dysfunctional EC mitochondria may contribute to cardiovascular disease by deregulating the shear-induced [Ca(2+)]i response.
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Affiliation(s)
- Christopher G Scheitlin
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Justin A Julian
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Santhanam Shanmughapriya
- Department of Medical Genetics and Molecular Biochemistry and Center for Translational Medicine, Temple University, Philadelphia, Pennsylvania; and
| | - Muniswamy Madesh
- Department of Medical Genetics and Molecular Biochemistry and Center for Translational Medicine, Temple University, Philadelphia, Pennsylvania; and
| | - Nikolaos M Tsoukias
- Department of Biomedical Engineering, Florida International University, Miami, Florida
| | - B Rita Alevriadou
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio;
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13
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Miragoli M, Sanchez-Alonso JL, Bhargava A, Wright PT, Sikkel M, Schobesberger S, Diakonov I, Novak P, Castaldi A, Cattaneo P, Lyon AR, Lab MJ, Gorelik J. Microtubule-Dependent Mitochondria Alignment Regulates Calcium Release in Response to Nanomechanical Stimulus in Heart Myocytes. Cell Rep 2015; 14:140-151. [PMID: 26725114 PMCID: PMC4983655 DOI: 10.1016/j.celrep.2015.12.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 09/07/2015] [Accepted: 11/23/2015] [Indexed: 12/01/2022] Open
Abstract
Arrhythmogenesis during heart failure is a major clinical problem. Regional electrical gradients produce arrhythmias, and cellular ionic transmembrane gradients are its originators. We investigated whether the nanoscale mechanosensitive properties of cardiomyocytes from failing hearts have a bearing upon the initiation of abnormal electrical activity. Hydrojets through a nanopipette indent specific locations on the sarcolemma and initiate intracellular calcium release in both healthy and heart failure cardiomyocytes, as well as in human failing cardiomyocytes. In healthy cells, calcium is locally confined, whereas in failing cardiomyocytes, calcium propagates. Heart failure progressively stiffens the membrane and displaces sub-sarcolemmal mitochondria. Colchicine in healthy cells mimics the failing condition by stiffening the cells, disrupting microtubules, shifting mitochondria, and causing calcium release. Uncoupling the mitochondrial proton gradient abolished calcium initiation in both failing and colchicine-treated cells. We propose the disruption of microtubule-dependent mitochondrial mechanosensor microdomains as a mechanism for abnormal calcium release in failing heart. Nanomechanical pressure application changes mechanosensitivity in failing heart cells Microtubular network disorganization mediates the change in mechanosensitivity Mitochondria are displaced from their original location and trigger calcium release Uncoupling the mitochondrial proton gradient completely abolishes the phenomena
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Affiliation(s)
- Michele Miragoli
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK; Humanitas Clinical and Research Center, via Manzoni 56, Rozzano, 20090 Milan, Italy; Center of Excellence for Toxicological Research, INAIL exISPESL, University of Parma, via Gramsci 14, 43126 Parma, Italy.
| | - Jose L Sanchez-Alonso
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK
| | - Anamika Bhargava
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK; Department of Biotechnology, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram, 502205 Telangana, India
| | - Peter T Wright
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK
| | - Markus Sikkel
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK
| | - Sophie Schobesberger
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK
| | - Ivan Diakonov
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK
| | - Pavel Novak
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK; School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Alessandra Castaldi
- Humanitas Clinical and Research Center, via Manzoni 56, Rozzano, 20090 Milan, Italy
| | - Paola Cattaneo
- Humanitas Clinical and Research Center, via Manzoni 56, Rozzano, 20090 Milan, Italy
| | - Alexander R Lyon
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK; NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London SW36NP, UK
| | - Max J Lab
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK.
| | - Julia Gorelik
- National Heart and Lung Institute, Imperial College London, 4th floor, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London W12 0NN, UK.
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Zhang XH, Wei H, Šarić T, Hescheler J, Cleemann L, Morad M. Regionally diverse mitochondrial calcium signaling regulates spontaneous pacing in developing cardiomyocytes. Cell Calcium 2015; 57:321-36. [PMID: 25746147 DOI: 10.1016/j.ceca.2015.02.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 01/28/2015] [Accepted: 02/10/2015] [Indexed: 12/16/2022]
Abstract
The quintessential property of developing cardiomyocytes is their ability to beat spontaneously. The mechanisms underlying spontaneous beating in developing cardiomyocytes are thought to resemble those of adult heart, but have not been directly tested. Contributions of sarcoplasmic and mitochondrial Ca(2+)-signaling vs. If-channel in initiating spontaneous beating were tested in human induced Pluripotent Stem cell-derived cardiomyocytes (hiPS-CM) and rat Neonatal cardiomyocytes (rN-CM). Whole-cell and perforated-patch voltage-clamping and 2-D confocal imaging showed: (1) both cell types beat spontaneously (60-140/min, at 24°C); (2) holding potentials between -70 and 0mV had no significant effects on spontaneous pacing, but suppressed action potential formation; (3) spontaneous pacing at -50mV activated cytosolic Ca(2+)-transients, accompanied by in-phase inward current oscillations that were suppressed by Na(+)-Ca(2+)-exchanger (NCX)- and ryanodine receptor (RyR2)-blockers, but not by Ca(2+)- and If-channels blockers; (4) spreading fluorescence images of cytosolic Ca(2+)-transients emanated repeatedly from preferred central cellular locations during spontaneous beating; (5) mitochondrial un-coupler, FCCP at non-depolarizing concentrations (∼50nM), reversibly suppressed spontaneous pacing; (6) genetically encoded mitochondrial Ca(2+)-biosensor (mitycam-E31Q) detected regionally diverse, and FCCP-sensitive mitochondrial Ca(2+)-uptake and release signals activating during INCX oscillations; (7) If-channel was absent in rN-CM, but activated only negative to -80mV in hiPS-CM; nevertheless blockers of If-channel failed to alter spontaneous pacing.
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Affiliation(s)
- Xiao-Hua Zhang
- Cardiac Signaling Center of USC, MUSC, & Clemson University, Charleston, SC, USA
| | - Hua Wei
- Cardiac Signaling Center of USC, MUSC, & Clemson University, Charleston, SC, USA
| | - Tomo Šarić
- Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany
| | - Jürgen Hescheler
- Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany
| | - Lars Cleemann
- Cardiac Signaling Center of USC, MUSC, & Clemson University, Charleston, SC, USA
| | - Martin Morad
- Cardiac Signaling Center of USC, MUSC, & Clemson University, Charleston, SC, USA.
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15
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Kim TJ, Joo C, Seong J, Vafabakhsh R, Botvinick EL, Berns MW, Palmer AE, Wang N, Ha T, Jakobsson E, Sun J, Wang Y. Distinct mechanisms regulating mechanical force-induced Ca²⁺ signals at the plasma membrane and the ER in human MSCs. eLife 2015; 4:e04876. [PMID: 25667984 PMCID: PMC4337650 DOI: 10.7554/elife.04876] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 01/21/2015] [Indexed: 12/21/2022] Open
Abstract
It is unclear that how subcellular organelles respond to external mechanical stimuli. Here, we investigated the molecular mechanisms by which mechanical force regulates Ca2+ signaling at endoplasmic reticulum (ER) in human mesenchymal stem cells. Without extracellular Ca2+, ER Ca2+ release is the source of intracellular Ca2+ oscillations induced by laser-tweezer-traction at the plasma membrane, providing a model to study how mechanical stimuli can be transmitted deep inside the cell body. This ER Ca2+ release upon mechanical stimulation is mediated not only by the mechanical support of cytoskeleton and actomyosin contractility, but also by mechanosensitive Ca2+ permeable channels on the plasma membrane, specifically TRPM7. However, Ca2+ influx at the plasma membrane via mechanosensitive Ca2+ permeable channels is only mediated by the passive cytoskeletal structure but not active actomyosin contractility. Thus, active actomyosin contractility is essential for the response of ER to the external mechanical stimuli, distinct from the mechanical regulation at the plasma membrane. DOI:http://dx.doi.org/10.7554/eLife.04876.001 Cells receive many signals from their environment, for example, when they are compressed or pulled about by neighboring cells. Information about these ‘mechanical stimuli’ can be transmitted within the cell to trigger changes in gene expression and cell behavior. When a cell receives a mechanical stimulus, it can activate the release of calcium ions from storage compartments within the cell, including from a compartment called the endoplasmic reticulum. Calcium ions can also enter the cell from outside via channels located in the membrane that surrounds the cell (the plasma membrane). Kim et al. investigated how mechanical forces are transmitted in a type of human cell called mesenchymal stem cells using optical tweezers to apply a gentle force to the outside of a cell. These tweezers use a laser to attract tiny objects, in this case a bead attached to proteins in the cell's outer membrane. The cell's response to this mechanical stimulation was measured using a sensor protein that fluoresces a different color when it binds to calcium ions. With this set-up, Kim et al. found that mesenchymal stem cells are able to transmit mechanical forces to different depths within the cell. The forces can travel deep to trigger the release of calcium ions from the endoplasmic reticulum. This process involves a network of protein fibers that criss-cross to support the structure of a cell—called the cytoskeleton—and also requires proteins that are associated with the cytoskeleton to contract. However, calcium ion entry through the plasma membrane due to a mechanical force does not require these contractile proteins—only the cytoskeleton is involved. These results demonstrate that the transmission of mechanical signals to different depths within mesenchymal stem cells involves different components. Future work should shed light on how these mechanical signals control gene expression and the development of mesenchymal stem cells. DOI:http://dx.doi.org/10.7554/eLife.04876.002
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Affiliation(s)
- Tae-Jin Kim
- Neuroscience Program, University of Illinois, Urbana-Champaign, Urbana, United States
| | - Chirlmin Joo
- Department of Physics, University of Illinois, Urbana-Champaign, Urbana, United States
| | - Jihye Seong
- Neuroscience Program, University of Illinois, Urbana-Champaign, Urbana, United States
| | - Reza Vafabakhsh
- Department of Physics, University of Illinois, Urbana-Champaign, Urbana, United States
| | - Elliot L Botvinick
- Department of Biomedical Engineering, Beckman Laser Institute, University of California, Irvine, Irvine, United States
| | - Michael W Berns
- Department of Biomedical Engineering, Beckman Laser Institute, University of California, Irvine, Irvine, United States
| | - Amy E Palmer
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Boulder, United States
| | - Ning Wang
- Department of Mechanical Science and Engineering, University of Illinois, Urbana-Champaign, Urbana, United States
| | - Taekjip Ha
- Department of Physics, University of Illinois, Urbana-Champaign, Urbana, United States
| | - Eric Jakobsson
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, United States
| | - Jie Sun
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, United States
| | - Yingxiao Wang
- Neuroscience Program, University of Illinois, Urbana-Champaign, Urbana, United States
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16
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Living cardiac tissue slices: an organotypic pseudo two-dimensional model for cardiac biophysics research. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:314-27. [PMID: 25124067 DOI: 10.1016/j.pbiomolbio.2014.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 08/02/2014] [Indexed: 11/24/2022]
Abstract
Living cardiac tissue slices, a pseudo two-dimensional (2D) preparation, have received less attention than isolated single cells, cell cultures, or Langendorff-perfused hearts in cardiac biophysics research. This is, in part, due to difficulties associated with sectioning cardiac tissue to obtain live slices. With moderate complexity, native cell-types, and well-preserved cell-cell electrical and mechanical interconnections, cardiac tissue slices have several advantages for studying cardiac electrophysiology. The trans-membrane potential (Vm) has, thus far, mainly been explored using multi-electrode arrays. Here, we combine tissue slices with optical mapping to monitor Vm and intracellular Ca(2+) concentration ([Ca(2+)]i). This combination opens up the possibility of studying the effects of experimental interventions upon action potential (AP) and calcium transient (CaT) dynamics in 2D, and with relatively high spatio-temporal resolution. As an intervention, we conducted proof-of-principle application of stretch. Mechanical stimulation of cardiac preparations is well-established for membrane patches, single cells and whole heart preparations. For cardiac tissue slices, it is possible to apply stretch perpendicular or parallel to the dominant orientation of cells, while keeping the preparation in a constant focal plane for fluorescent imaging of in-slice functional dynamics. Slice-to-slice comparison furthermore allows one to assess transmural differences in ventricular tissue responses to mechanical challenges. We developed and tested application of axial stretch to cardiac tissue slices, using a manually-controlled stretching device, and recorded Vm and [Ca(2+)]i by optical mapping before, during, and after application of stretch. Living cardiac tissue slices, exposed to axial stretch, show an initial shortening in both AP and CaT duration upon stretch application, followed in most cases by a gradual prolongation of AP and CaT duration during stretch maintained for up to 50 min. After release of sustained stretch, AP duration (APD) and CaT duration reverted to shorter values. Living cardiac tissue slices are a promising experimental model for the study of cardiac mechano-electric interactions. The methodology described here can be refined to achieve more accurate control over stretch amplitude and timing (e.g. using a computer-controlled motorised stage, or by synchronising electrical and mechanical events) and through monitoring of regional tissue deformation (e.g. by adding motion tracking).
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Reed A, Kohl P, Peyronnet R. Molecular candidates for cardiac stretch-activated ion channels. Glob Cardiol Sci Pract 2014; 2014:9-25. [PMID: 25405172 PMCID: PMC4220428 DOI: 10.5339/gcsp.2014.19] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 06/08/2014] [Indexed: 01/20/2023] Open
Abstract
The heart is a mechanically-active organ that dynamically senses its own mechanical environment. This environment is constantly changing, on a beat-by-beat basis, with additional modulation by respiratory activity and changes in posture or physical activity, and further overlaid with more slowly occurring physiological (e.g. pregnancy, endurance training) or pathological challenges (e.g. pressure or volume overload). Far from being a simple pump, the heart detects changes in mechanical demand and adjusts its performance accordingly, both via heart rate and stroke volume alteration. Many of the underlying regulatory processes are encoded intracardially, and are thus maintained even in heart transplant recipients. Over the last three decades, molecular substrates of cardiac mechanosensitivity have gained increasing recognition in the scientific and clinical communities. Nonetheless, the processes underlying this phenomenon are still poorly understood. Stretch-activated ion channels (SAC) have been identified as one contributor to mechanosensitive autoregulation of the heartbeat. They also appear to play important roles in the development of cardiac pathologies – most notably stretch-induced arrhythmias. As recently discovered, some established cardiac drugs act, in part at least, via mechanotransduction pathways suggesting SAC as potential therapeutic targets. Clearly, identification of the molecular substrate of cardiac SAC is of clinical importance and a number of candidate proteins have been identified. At the same time, experimental studies have revealed variable–and at times contrasting–results regarding their function. Further complication arises from the fact that many ion channels that are not classically defined as SAC, including voltage and ligand-gated ion channels, can respond to mechanical stimulation. Here, we summarise what is known about the molecular substrate of the main candidates for cardiac SAC, before identifying potential further developments in this area of translational research.
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Affiliation(s)
- Alistair Reed
- Medical Sciences Division, University of Oxford, United Kingdom
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18
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Rosa AO, Movafagh S, Cleemann L, Morad M. Hypoxic regulation of cardiac Ca2+ channel: possible role of haem oxygenase. J Physiol 2012; 590:4223-37. [PMID: 22753548 DOI: 10.1113/jphysiol.2012.236570] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Acute and chronic hypoxias are common cardiac diseases that lead often to arrhythmia and impaired contractility. At the cellular level it is unclear whether the suppression of cardiac Ca(2+) channels (Ca(V)1.2) results directly from oxygen deprivation on the channel protein or is mediated by intermediary proteins affecting the channel. To address this question we measured the early effects of hypoxia (5-60 s, P(O(2)) < 5 mmHg) on Ca(2+) current (I(Ca)) and tested the involvement of protein kinase A (PKA) phosphorylation, Ca(2+)/calmodulin-mediated signalling and the haem oxygenase (HO) pathway in the hypoxic regulation of Ca(V)1.2 in rat and cat ventricular myocytes and HEK-293 cells. Hypoxic suppression of ICa) and Ca(2+) transients was significant within 5 s and intensified in the following 50 s, and was reversible. Phosphorylation by cAMP or the phosphatase inhibitor okadaic acid desensitized I(Ca) to hypoxia, while PKA inhibition by H-89 restored the sensitivity of I(Ca) to hypoxia. This phosphorylation effect was specific to Ca(2+), but not Ba(2+) or Na(+), permeating through the channel. CaMKII inhibitory peptide and Bay K8644 reversed the phosphorylation-induced desensitization to hypoxia. Mutation of CAM/CaMKII-binding motifs of the α(1c) subunit of Ca(V)1.2 fully desensitized the Ca(2+) channel to hypoxia. Rapid application of HO inhibitors (zinc protoporphyrin (ZnPP) and tin protoporphyrin (SnPP)) suppressed the channel in a manner similar to acute hypoxia such that: (1) I(Ca) and I(Ba) were suppressed within 5 s of ZnPP application; (2) PKA activation and CaMKII inhibitors desensitized I(Ca), but not I(Ba), to ZnPP; and (3) hypoxia failed to further suppress I(Ca) and I(Ba) in ZnPP-treated myocytes. We propose that the binding of HO to the CaM/CaMKII-specific motifs on Ca(2+) channel may mediate the rapid response of the channel to hypoxia.
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Affiliation(s)
- Angelo O Rosa
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, Charleston, SC 29245, USA
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19
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Pandit MM, Strait KA, Matsuda T, Kohan DE. Na delivery and ENaC mediate flow regulation of collecting duct endothelin-1 production. Am J Physiol Renal Physiol 2012; 302:F1325-30. [PMID: 22357920 PMCID: PMC3362067 DOI: 10.1152/ajprenal.00034.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 02/21/2012] [Indexed: 11/22/2022] Open
Abstract
Collecting duct (CD) endothelin-1 (ET-1) is an important autocrine inhibitor of Na and water transport. CD ET-1 production is stimulated by extracellular fluid volume expansion and tubule fluid flow, suggesting a mechanism coupling CD Na delivery and ET-1 synthesis. A mouse cortical CD cell line, mpkCCDc14, was subjected to static or flow conditions for 2 h at 2 dyn/cm(2), followed by determination of ET-1 mRNA content. Flow with 300 mosmol/l NaCl increased ET-1 mRNA to 65% above that observed under static conditions. Increasing perfusate osmolarity to 450 mosmol/l with NaCl or Na acetate increased ET-1 mRNA to ∼184% compared with no flow, which was not observed when osmolarity was increased using mannitol or urea. Reducing Na concentration to 150 mosmol/l while maintaining total osmolarity at 300 mosmol/l with urea or mannitol decreased the flow response. Inhibition of epithelial Na channel (ENaC) with amiloride or benzamil abolished the flow response, suggesting involvement of ENaC in flow-regulated ET-1 synthesis. Aldosterone almost doubled the flow response. Since Ca(2+) enhances CD ET-1 production, the involvement of plasma membrane and mitochondrial Na/Ca(2+) exchangers (NCX) was assessed. SEA0400 and KB-R7943, plasma membrane NCX inhibitors, did not affect the flow response. However, CGP37157, a mitochondrial NCX inhibitor, abolished the response. In summary, the current study indicates that increased Na delivery, leading to ENaC-mediated Na entry and mitochondrial NCX activity, is involved in flow-stimulated CD ET-1 synthesis. This constitutes the first report of either ENaC or mitochondrial NCX regulation of an autocrine factor in any biologic system.
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Affiliation(s)
- Meghana M Pandit
- Division of Nephrology, University of Utah Health Sciences Center, 1900 East, 30 North, Salt Lake City, UT 84132, USA
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20
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Chan DD, Van Dyke WS, Bahls M, Connell SD, Critser P, Kelleher JE, Kramer MA, Pearce SM, Sharma S, Neu CP. Mechanostasis in apoptosis and medicine. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 106:517-24. [PMID: 21846479 DOI: 10.1016/j.pbiomolbio.2011.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 08/02/2011] [Indexed: 10/17/2022]
Abstract
Mechanostasis describes a complex and dynamic process where cells maintain equilibrium in response to mechanical forces. Normal physiological loading modes and magnitudes contribute to cell proliferation, tissue growth, differentiation and development. However, cell responses to abnormal forces include compensatory apoptotic mechanisms that may contribute to the development of tissue disease and pathological conditions. Mechanotransduction mechanisms tightly regulate the cell response through discrete signaling pathways. Here, we provide an overview of links between pro- and anti-apoptotic signaling and mechanotransduction signaling pathways, and identify potential clinical applications for treatments of disease by exploiting mechanically-linked apoptotic pathways.
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Affiliation(s)
- D D Chan
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
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21
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Bollensdorff C, Lookin O, Kohl P. Assessment of contractility in intact ventricular cardiomyocytes using the dimensionless 'Frank-Starling Gain' index. Pflugers Arch 2011; 462:39-48. [PMID: 21494804 PMCID: PMC3114067 DOI: 10.1007/s00424-011-0964-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 03/28/2011] [Accepted: 03/28/2011] [Indexed: 11/29/2022]
Abstract
This paper briefly recapitulates the Frank-Starling law of the heart, reviews approaches to establishing diastolic and systolic force-length behaviour in intact isolated cardiomyocytes, and introduces a dimensionless index called 'Frank-Starling Gain', calculated as the ratio of slopes of end-systolic and end-diastolic force-length relations. The benefits and limitations of this index are illustrated on the example of regional differences in Guinea pig intact ventricular cardiomyocyte mechanics. Potential applicability of the Frank-Starling Gain for the comparison of cell contractility changes upon stretch will be discussed in the context of intra- and inter-individual variability of cardiomyocyte properties.
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Affiliation(s)
- Christian Bollensdorff
- Cardiac Biophysics and Systems Biology, The National Heart and Lung Institute, Imperial College, London, UK.
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22
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Lu FH, Tian Z, Zhang WH, Zhao YJ, Li HL, Ren H, Zheng HS, Liu C, Hu GX, Tian Y, Yang BF, Wang R, Xu CQ. Calcium-sensing receptors regulate cardiomyocyte Ca2+ signaling via the sarcoplasmic reticulum-mitochondrion interface during hypoxia/reoxygenation. J Biomed Sci 2010; 17:50. [PMID: 20565791 PMCID: PMC2908572 DOI: 10.1186/1423-0127-17-50] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2009] [Accepted: 06/17/2010] [Indexed: 01/21/2023] Open
Abstract
Communication between the SR (sarcoplasmic reticulum, SR) and mitochondria is important for cell survival and apoptosis. The SR supplies Ca2+ directly to mitochondria via inositol 1,4,5-trisphosphate receptors (IP3Rs) at close contacts between the two organelles referred to as mitochondrion-associated ER membrane (MAM). Although it has been demonstrated that CaR (calcium sensing receptor) activation is involved in intracellular calcium overload during hypoxia/reoxygenation (H/Re), the role of CaR activation in the cardiomyocyte apoptotic pathway remains unclear. We postulated that CaR activation plays a role in the regulation of SR-mitochondrial inter-organelle Ca2+ signaling, causing apoptosis during H/Re. To investigate the above hypothesis, cultured cardiomyocytes were subjected to H/Re. We examined the distribution of IP3Rs in cardiomyocytes via immunofluorescence and Western blotting and found that type 3 IP3Rs were located in the SR. [Ca2+]i, [Ca2+]m and [Ca2+]SR were determined using Fluo-4, x-rhod-1 and Fluo 5N, respectively, and the mitochondrial membrane potential was detected with JC-1 during reoxygenation using laser confocal microscopy. We found that activation of CaR reduced [Ca2+]SR, increased [Ca2+]i and [Ca2+]m and decreased the mitochondrial membrane potential during reoxygenation. We found that the activation of CaR caused the cleavage of BAP31, thus generating the pro-apoptotic p20 fragment, which induced the release of cytochrome c from mitochondria and the translocation of bak/bax to mitochondria. Taken together, these results reveal that CaR activation causes Ca2+ release from the SR into the mitochondria through IP3Rs and induces cardiomyocyte apoptosis during hypoxia/reoxygenation.
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Affiliation(s)
- Fang-hao Lu
- Department of Pathophysiology, Harbin Medical University, Harbin 150086, China
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23
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Kawamura Y, Ishiwata T, Takizawa M, Ishida H, Asano Y, Nonoyama S. Fetal and neonatal development of Ca2+ transients and functional sarcoplasmic reticulum in beating mouse hearts. Circ J 2010; 74:1442-50. [PMID: 20526040 DOI: 10.1253/circj.cj-09-0793] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND It is generally accepted that Ca(2+)-induced Ca(2+) release is not the predominant mechanism during embryonic stages. Most studies have been conducted either on primary cultures or acutely isolated cells, in which an apparent reduction of ryanodine receptor density and alterations in the cell shape have been reported. The aim of the present study was to investigate developmental changes in Ca(2+) transients using whole hearts of mouse embryos and neonates. METHODS AND RESULTS Fluo-3 fluorescence signals from stimulated whole hearts were detected using a photomultiplier and stored as Ca(2+) transients. The upstroke and decay of Ca(2+) transients became more rapid from the late embryonic stages to the neonatal stage. After thapsigargin application (an inhibitor of the sarcoplasmic Ca(2+)-ATPase [SERCA]), time to 50% relaxation (T(50)) of Ca(2+) transients was significantly prolonged. There were no significant changes in T(50) after Ru360 application (an inhibitor of mitochondrial Ca(2+) uniporter). The rate of increase in the amplitude of Ca(2+) transients after caffeine application became larger during developmental stages. CONCLUSIONS Ca(2+) homeostasis developmentally changes from a slow rise and decay of Ca(2+) transients to rapid kinetics after the mid-embryonic stage. SERCA began to contribute significantly to Ca(2+) homeostasis at early embryonic stages and sarcoplasmic reticulum Ca(2+) contents increased from embryonic to neonatal stages, whereas mitochondrial Ca(2+) uptake did not contribute to Ca(2+) transients on a beat-to-beat basis.
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Affiliation(s)
- Yoichi Kawamura
- Department of Pediatrics, National Defense Medical College, Tokorozawa, Japan
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24
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Mitochondrial calcium transport in the heart: Physiological and pathological roles. J Mol Cell Cardiol 2009; 46:789-803. [DOI: 10.1016/j.yjmcc.2009.03.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 02/28/2009] [Accepted: 03/03/2009] [Indexed: 12/20/2022]
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25
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