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Kalamgi RC, Larsson L. Mechanical Signaling in the Pathophysiology of Critical Illness Myopathy. Front Physiol 2016; 7:23. [PMID: 26869939 PMCID: PMC4740381 DOI: 10.3389/fphys.2016.00023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/18/2016] [Indexed: 12/14/2022] Open
Abstract
The complete loss of mechanical stimuli of skeletal muscles, i.e., the loss of external strain, related to weight bearing, and internal strain, related to the contraction of muscle cells, is uniquely observed in pharmacologically paralyzed or deeply sedated mechanically ventilated intensive care unit (ICU) patients. The preferential loss of myosin and myosin associated proteins in limb and trunk muscles is a significant characteristic of critical illness myopathy (CIM) which separates CIM from other types of acquired muscle weaknesses in ICU patients. Mechanical silencing is an important factor triggering CIM. Microgravity or ground based microgravity models form the basis of research on the effect of muscle unloading-reloading, but the mechanisms and effects may differ from the ICU conditions. In order to understand how mechanical tension regulates muscle mass, it is critical to know how muscles sense mechanical information and convert stimulus to intracellular biochemical actions and changes in gene expression, a process called cellular mechanotransduction. In adult skeletal muscles and muscle fibers, this process may differ, the same stimulus can cause divergent response and the same fiber type may undergo opposite changes in different muscles. Skeletal muscle contains multiple types of mechano-sensors and numerous structures that can be affected differently and hence respond differently in distinct muscles.
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Affiliation(s)
- Rebeca C Kalamgi
- Basic and Clinical Muscle Biology, Department of Physiology and Pharmacology, Karolinska Institutet Stockholm, Sweden
| | - Lars Larsson
- Basic and Clinical Muscle Biology, Department of Physiology and Pharmacology, Karolinska InstitutetStockholm, Sweden; Department of Clinical Neuroscience, Clinical Neurophysiology, Karolinska InstitutetStockholm, Sweden
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Capulli AK, MacQueen LA, Sheehy SP, Parker KK. Fibrous scaffolds for building hearts and heart parts. Adv Drug Deliv Rev 2016; 96:83-102. [PMID: 26656602 PMCID: PMC4807693 DOI: 10.1016/j.addr.2015.11.020] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/24/2015] [Accepted: 11/26/2015] [Indexed: 12/14/2022]
Abstract
Extracellular matrix (ECM) structure and biochemistry provide cell-instructive cues that promote and regulate tissue growth, function, and repair. From a structural perspective, the ECM is a scaffold that guides the self-assembly of cells into distinct functional tissues. The ECM promotes the interaction between individual cells and between different cell types, and increases the strength and resilience of the tissue in mechanically dynamic environments. From a biochemical perspective, factors regulating cell-ECM adhesion have been described and diverse aspects of cell-ECM interactions in health and disease continue to be clarified. Natural ECMs therefore provide excellent design rules for tissue engineering scaffolds. The design of regenerative three-dimensional (3D) engineered scaffolds is informed by the target ECM structure, chemistry, and mechanics, to encourage cell infiltration and tissue genesis. This can be achieved using nanofibrous scaffolds composed of polymers that simultaneously recapitulate 3D ECM architecture, high-fidelity nanoscale topography, and bio-activity. Their high porosity, structural anisotropy, and bio-activity present unique advantages for engineering 3D anisotropic tissues. Here, we use the heart as a case study and examine the potential of ECM-inspired nanofibrous scaffolds for cardiac tissue engineering. We asked: Do we know enough to build a heart? To answer this question, we tabulated structural and functional properties of myocardial and valvular tissues for use as design criteria, reviewed nanofiber manufacturing platforms and assessed their capabilities to produce scaffolds that meet our design criteria. Our knowledge of the anatomy and physiology of the heart, as well as our ability to create synthetic ECM scaffolds have advanced to the point that valve replacement with nanofibrous scaffolds may be achieved in the short term, while myocardial repair requires further study in vitro and in vivo.
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Affiliation(s)
- A K Capulli
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - L A MacQueen
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Sean P Sheehy
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - K K Parker
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
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Neves JS, Leite-Moreira AM, Neiva-Sousa M, Almeida-Coelho J, Castro-Ferreira R, Leite-Moreira AF. Acute Myocardial Response to Stretch: What We (don't) Know. Front Physiol 2016; 6:408. [PMID: 26779036 PMCID: PMC4700209 DOI: 10.3389/fphys.2015.00408] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/11/2015] [Indexed: 12/24/2022] Open
Abstract
Myocardial stretch, as result of acute hemodynamic overload, is one of the most frequent challenges to the heart and the ability of the heart to intrinsically adapt to it is essential to prevent circulatory congestion. In this review, we highlight the historical background, the currently known mechanisms, as well as the gaps in the understanding of this physiological response. The systolic adaptation to stretch is well-known for over 100 years, being dependent on an immediate increase in contractility—known as the Frank-Starling mechanism—and a further progressive increase—the slow force response. On the other hand, its diastolic counterpart remains largely unstudied. Mechanosensors are structures capable of perceiving mechanical signals and activating pathways that allow their transduction into biochemical responses. Although the connection between these structures and stretch activated pathways remains elusive, we emphasize those most likely responsible for the initiation of the acute response. Calcium-dependent pathways, including angiotensin- and endothelin-related pathways; and cGMP-dependent pathways, comprising the effects of nitric oxide and cardiac natriuretic hormones, embody downstream signaling. The ischemic setting, a paradigmatic situation of acute hemodynamic overload, is also touched upon. Despite the relevant knowledge accumulated, there is much that we still do not know. The quest for further understanding the myocardial response to acute stretch may provide new insights, not only in its physiological importance, but also in the prevention and treatment of cardiovascular diseases.
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Affiliation(s)
- João S Neves
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine of the University of Porto Porto, Portugal
| | - André M Leite-Moreira
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine of the University of Porto Porto, Portugal
| | - Manuel Neiva-Sousa
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine of the University of Porto Porto, Portugal
| | - João Almeida-Coelho
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine of the University of Porto Porto, Portugal
| | - Ricardo Castro-Ferreira
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine of the University of Porto Porto, Portugal
| | - Adelino F Leite-Moreira
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine of the University of Porto Porto, Portugal
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Abstract
Vascular smooth muscle (VSM; see Table 1 for a list of abbreviations) is a heterogeneous biomaterial comprised of cells and extracellular matrix. By surrounding tubes of endothelial cells, VSM forms a regulated network, the vasculature, through which oxygenated blood supplies specialized organs, permitting the development of large multicellular organisms. VSM cells, the engine of the vasculature, house a set of regulated nanomotors that permit rapid stress-development, sustained stress-maintenance and vessel constriction. Viscoelastic materials within, surrounding and attached to VSM cells, comprised largely of polymeric proteins with complex mechanical characteristics, assist the engine with countering loads imposed by the heart pump, and with control of relengthening after constriction. The complexity of this smart material can be reduced by classical mechanical studies combined with circuit modeling using spring and dashpot elements. Evaluation of the mechanical characteristics of VSM requires a more complete understanding of the mechanics and regulation of its biochemical parts, and ultimately, an understanding of how these parts work together to form the machinery of the vascular tree. Current molecular studies provide detailed mechanical data about single polymeric molecules, revealing viscoelasticity and plasticity at the protein domain level, the unique biological slip-catch bond, and a regulated two-step actomyosin power stroke. At the tissue level, new insight into acutely dynamic stress-strain behavior reveals smooth muscle to exhibit adaptive plasticity. At its core, physiology aims to describe the complex interactions of molecular systems, clarifying structure-function relationships and regulation of biological machines. The intent of this review is to provide a comprehensive presentation of one biomachine, VSM.
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Affiliation(s)
- Paul H Ratz
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
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55
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Ultrastructural myocardial changes in seven cats with spontaneous hypertrophic cardiomyopathy. J Vet Cardiol 2015; 17 Suppl 1:S220-32. [DOI: 10.1016/j.jvc.2015.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 10/05/2015] [Accepted: 10/15/2015] [Indexed: 11/22/2022]
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Brody MJ, Feng L, Grimes AC, Hacker TA, Olson TM, Kamp TJ, Balijepalli RC, Lee Y. LRRC10 is required to maintain cardiac function in response to pressure overload. Am J Physiol Heart Circ Physiol 2015; 310:H269-78. [PMID: 26608339 DOI: 10.1152/ajpheart.00717.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 11/18/2015] [Indexed: 01/08/2023]
Abstract
We previously reported that the cardiomyocyte-specific leucine-rich repeat containing protein (LRRC)10 has critical functions in the mammalian heart. In the present study, we tested the role of LRRC10 in the response of the heart to biomechanical stress by performing transverse aortic constriction on Lrrc10-null (Lrrc10(-/-)) mice. Mild pressure overload induced severe cardiac dysfunction and ventricular dilation in Lrrc10(-/-) mice compared with control mice. In addition to dilation and cardiomyopathy, Lrrc10(-/-) mice showed a pronounced increase in heart weight with pressure overload stimulation and a more dramatic loss of cardiac ventricular performance, collectively suggesting that the absence of LRRC10 renders the heart more disease prone with greater hypertrophy and structural remodeling, although rates of cardiac fibrosis and myocyte dropout were not different from control mice. Lrrc10(-/-) cardiomyocytes also exhibited reduced contractility in response to β-adrenergic stimulation, consistent with loss of cardiac ventricular performance after pressure overload. We have previously shown that LRRC10 interacts with actin in the heart. Here, we show that His(150) of LRRC10 was required for an interaction with actin, and this interaction was reduced after pressure overload, suggesting an integral role for LRRC10 in the response of the heart to mechanical stress. Importantly, these experiments demonstrated that LRRC10 is required to maintain cardiac performance in response to pressure overload and suggest that dysregulated expression or mutation of LRRC10 may greatly sensitize human patients to more severe cardiac disease in conditions such as chronic hypertension or aortic stenosis.
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Affiliation(s)
- Matthew J Brody
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Molecular and Environmental Toxicology Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Li Feng
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Adrian C Grimes
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Timothy A Hacker
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Timothy M Olson
- Cardiovascular Genetics Research Laboratory and Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
| | - Timothy J Kamp
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Ravi C Balijepalli
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Youngsook Lee
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Molecular and Environmental Toxicology Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin;
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57
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Pressure Overload by Transverse Aortic Constriction Induces Maladaptive Hypertrophy in a Titin-Truncated Mouse Model. BIOMED RESEARCH INTERNATIONAL 2015; 2015:163564. [PMID: 26504781 PMCID: PMC4609346 DOI: 10.1155/2015/163564] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 08/16/2015] [Indexed: 11/17/2022]
Abstract
Mutations in the giant sarcomeric protein titin (TTN) are a major cause for inherited forms of dilated cardiomyopathy (DCM). We have previously developed a mouse model that imitates a TTN truncation mutation we found in a large pedigree with DCM. While heterozygous Ttn knock-in mice do not display signs of heart failure under sedentary conditions, they recapitulate the human phenotype when exposed to the pharmacological stressor angiotensin II or isoproterenol. In this study we investigated the effects of pressure overload by transverse aortic constriction (TAC) in heterozygous (Het) Ttn knock-in mice. Two weeks after TAC, Het mice developed marked impairment of left ventricular ejection fraction (p < 0.05), while wild-type (WT) TAC mice did not. Het mice also trended toward increased ventricular end diastolic pressure and volume compared to WT littermates. We found an increase in histologically diffuse cardiac fibrosis in Het compared to WT in TAC mice. This study shows that a pattern of DCM can be induced by TAC-mediated pressure overload in a TTN-truncated mouse model. This model enlarges our arsenal of cardiac disease models, adding a valuable tool to understand cardiac pathophysiological remodeling processes and to develop therapeutic approaches to combat heart failure.
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58
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Ramirez-Correa GA, Ma J, Slawson C, Zeidan Q, Lugo-Fagundo NS, Xu M, Shen X, Gao WD, Caceres V, Chakir K, DeVine L, Cole RN, Marchionni L, Paolocci N, Hart GW, Murphy AM. Removal of Abnormal Myofilament O-GlcNAcylation Restores Ca2+ Sensitivity in Diabetic Cardiac Muscle. Diabetes 2015; 64:3573-87. [PMID: 26109417 PMCID: PMC4587639 DOI: 10.2337/db14-1107] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 05/14/2015] [Indexed: 11/13/2022]
Abstract
Contractile dysfunction and increased deposition of O-linked β-N-acetyl-d-glucosamine (O-GlcNAc) in cardiac proteins are a hallmark of the diabetic heart. However, whether and how this posttranslational alteration contributes to lower cardiac function remains unclear. Using a refined β-elimination/Michael addition with tandem mass tags (TMT)-labeling proteomic technique, we show that CpOGA, a bacterial analog of O-GlcNAcase (OGA) that cleaves O-GlcNAc in vivo, removes site-specific O-GlcNAcylation from myofilaments, restoring Ca(2+) sensitivity in streptozotocin (STZ) diabetic cardiac muscles. We report that in control rat hearts, O-GlcNAc and O-GlcNAc transferase (OGT) are mainly localized at the Z-line, whereas OGA is at the A-band. Conversely, in diabetic hearts O-GlcNAc levels are increased and OGT and OGA delocalized. Consistent changes were found in human diabetic hearts. STZ diabetic hearts display increased physical interactions of OGA with α-actin, tropomyosin, and myosin light chain 1, along with reduced OGT and increased OGA activities. Our study is the first to reveal that specific removal of O-GlcNAcylation restores myofilament response to Ca(2+) in diabetic hearts and that altered O-GlcNAcylation is due to the subcellular redistribution of OGT and OGA rather than to changes in their overall activities. Thus, preventing sarcomeric OGT and OGA displacement represents a new possible strategy for treating diabetic cardiomyopathy.
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Affiliation(s)
- Genaro A Ramirez-Correa
- Division of Cardiology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Junfeng Ma
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Chad Slawson
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS
| | - Quira Zeidan
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nahyr S Lugo-Fagundo
- Division of Cardiology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Mingguo Xu
- Division of Cardiology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Xiaoxu Shen
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Wei Dong Gao
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Viviane Caceres
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Khalid Chakir
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Lauren DeVine
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Robert N Cole
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Luigi Marchionni
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nazareno Paolocci
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Gerald W Hart
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Anne M Murphy
- Division of Cardiology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
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59
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QU XINKAI, YUAN FANG, LI RUOGU, XU LEI, JING WEIFENG, LIU HUA, XU YINGJIA, ZHANG MIN, LIU XU, FANG WEIYI, YANG YIQING, QIU XINGBIAO. Prevalence and spectrum of LRRC10 mutations associated with idiopathic dilated cardiomyopathy. Mol Med Rep 2015; 12:3718-3724. [DOI: 10.3892/mmr.2015.3843] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 05/01/2015] [Indexed: 11/06/2022] Open
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60
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Thornell LE, Carlsson L, Eriksson PO, Liu JX, Österlund C, Stål P, Pedrosa-Domellöf F. Fibre typing of intrafusal fibres. J Anat 2015; 227:136-56. [PMID: 26179023 PMCID: PMC4523317 DOI: 10.1111/joa.12338] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2015] [Indexed: 12/23/2022] Open
Abstract
The first descriptions of muscle spindles with intrafusal fibres containing striated myofibrils and nervous elements were given approximately 150 years ago. It took, however, another 100 years to establish the presence of two types of intrafusal muscle fibres: nuclear bag and nuclear chain fibres. The present paper highlights primarily the contribution of Robert Banks in fibre typing of intrafusal fibres: the confirmation of the principle of two types of nuclear bag fibres in mammalian spindles and the variation in occurrence of a dense M-band along the fibres. Furthermore, this paper summarizes how studies from the Umeå University group (Laboratory of Muscle Biology in the Department of Integrative Medical Biology) on fibre typing and the structure and composition of M-bands have contributed to the current understanding of muscle spindle complexity in adult humans as well as to muscle spindle development and effects of ageing. The variable molecular composition of the intrafusal sarcomeres with respect to myosin heavy chains and M-band proteins gives new perspectives on the role of the intrafusal myofibrils as stretch-activated sensors influencing tension/stiffness and signalling to nuclei.
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Affiliation(s)
- Lars-Eric Thornell
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
| | - Lena Carlsson
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
| | - Per-Olof Eriksson
- Department of Odontology, Clinical Oral Physiology, Umeå UniversityUmeå, Sweden
| | - Jing-Xia Liu
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
| | - Catharina Österlund
- Department of Odontology, Clinical Oral Physiology, Umeå UniversityUmeå, Sweden
| | - Per Stål
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
| | - Fatima Pedrosa-Domellöf
- Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå UniversityUmeå, Sweden
- Department of Clinical Sciences, Ophthalmology, Umeå UniversityUmeå, Sweden
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61
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Waddingham MT, Edgley AJ, Tsuchimochi H, Kelly DJ, Shirai M, Pearson JT. Contractile apparatus dysfunction early in the pathophysiology of diabetic cardiomyopathy. World J Diabetes 2015; 6:943-960. [PMID: 26185602 PMCID: PMC4499528 DOI: 10.4239/wjd.v6.i7.943] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 12/30/2014] [Accepted: 03/09/2015] [Indexed: 02/05/2023] Open
Abstract
Diabetes mellitus significantly increases the risk of cardiovascular disease and heart failure in patients. Independent of hypertension and coronary artery disease, diabetes is associated with a specific cardiomyopathy, known as diabetic cardiomyopathy (DCM). Four decades of research in experimental animal models and advances in clinical imaging techniques suggest that DCM is a progressive disease, beginning early after the onset of type 1 and type 2 diabetes, ahead of left ventricular remodeling and overt diastolic dysfunction. Although the molecular pathogenesis of early DCM still remains largely unclear, activation of protein kinase C appears to be central in driving the oxidative stress dependent and independent pathways in the development of contractile dysfunction. Multiple subcellular alterations to the cardiomyocyte are now being highlighted as critical events in the early changes to the rate of force development, relaxation and stability under pathophysiological stresses. These changes include perturbed calcium handling, suppressed activity of aerobic energy producing enzymes, altered transcriptional and posttranslational modification of membrane and sarcomeric cytoskeletal proteins, reduced actin-myosin cross-bridge cycling and dynamics, and changed myofilament calcium sensitivity. In this review, we will present and discuss novel aspects of the molecular pathogenesis of early DCM, with a special focus on the sarcomeric contractile apparatus.
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62
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Caldwell TA, Sumner I, Wright NT. Mechanical dissociation of the M-band titin/obscurin complex is directionally dependent. FEBS Lett 2015; 589:1735-9. [PMID: 26001486 DOI: 10.1016/j.febslet.2015.05.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 11/29/2022]
Abstract
Titin and obscurin, two giant muscle proteins, bind to each other in an antiparallel Ig-Ig fashion at the M-band. This interaction must be able to withstand the mechanical strain that the M-band typically experiences and remain intact. The mechanical force on these domains is likely exerted along one of two axes: a longitudinal axis, resulting in a 'shearing' force, or a lateral axis, resulting in a 'peeling' force. Here we present molecular dynamics data suggesting that these forces result in distinct unraveling pathways of the titin/obscurin complex and that peeling the domains apart requires less work and force.
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Affiliation(s)
- Tracy A Caldwell
- Department of Chemistry and Biochemistry, James Madison University, 901 Carrier Dr., Harrisonburg, VA 22807, United States
| | - Isaiah Sumner
- Department of Chemistry and Biochemistry, James Madison University, 901 Carrier Dr., Harrisonburg, VA 22807, United States
| | - Nathan T Wright
- Department of Chemistry and Biochemistry, James Madison University, 901 Carrier Dr., Harrisonburg, VA 22807, United States.
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63
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Verstraelen TE, Ter Bekke RMA, Volders PGA, Masclee AAM, Kruimel JW. The role of the SCN5A-encoded channelopathy in irritable bowel syndrome and other gastrointestinal disorders. Neurogastroenterol Motil 2015; 27:906-13. [PMID: 25898860 DOI: 10.1111/nmo.12569] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/17/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND Gastrointestinal functional and motility disorders, like irritable bowel syndrome (IBS), have a high prevalence in the Western population and cause significant morbidity and loss of quality of life leading to considerable costs for health care. A decade ago, it has been demonstrated that interstitial cells of Cajal and intestinal smooth muscle cells, cells important for gastrointestinal motility, express the sodium channel alpha subunit Nav 1.5. In the heart, aberrant variants in this sodium channel, encoded by SCN5A, are linked to inherited arrhythmia syndromes, like the long-QT syndrome type 3 and Brugada syndrome. Mounting data show a possible contribution of SCN5A mutants to gastrointestinal functional and motility disorders. Two percent of IBS patients harbor SCN5A mutations with electrophysiological evidence of loss- and gain-of-function. In addition, gastrointestinal symptoms are more prevalent in cardiac SCN5A-mutation positive patients. PURPOSE This review firstly describes the Nav 1.5 channel and its physiological role in ventricular cardiomyocytes and gastrointestinal cells, then we focus on the involvement of mutant Nav 1.5 in gastrointestinal functional and motility disorders. Future research might uncover novel mutation-specific treatment strategies for SCN5A-encoded gastrointestinal channelopathies.
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Affiliation(s)
- T E Verstraelen
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - R M A Ter Bekke
- Department of Cardiology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - P G A Volders
- Department of Cardiology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - A A M Masclee
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - J W Kruimel
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
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64
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Kaushik G, Spenlehauer A, Sessions AO, Trujillo AS, Fuhrmann A, Fu Z, Venkatraman V, Pohl D, Tuler J, Wang M, Lakatta EG, Ocorr K, Bodmer R, Bernstein SI, Van Eyk JE, Cammarato A, Engler AJ. Vinculin network-mediated cytoskeletal remodeling regulates contractile function in the aging heart. Sci Transl Med 2015; 7:292ra99. [PMID: 26084806 PMCID: PMC4507505 DOI: 10.1126/scitranslmed.aaa5843] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The human heart is capable of functioning for decades despite minimal cell turnover or regeneration, suggesting that molecular alterations help sustain heart function with age. However, identification of compensatory remodeling events in the aging heart remains elusive. We present the cardiac proteomes of young and old rhesus monkeys and rats, from which we show that certain age-associated remodeling events within the cardiomyocyte cytoskeleton are highly conserved and beneficial rather than deleterious. Targeted transcriptomic analysis in Drosophila confirmed conservation and implicated vinculin as a unique molecular regulator of cardiac function during aging. Cardiac-restricted vinculin overexpression reinforced the cortical cytoskeleton and enhanced myofilament organization, leading to improved contractility and hemodynamic stress tolerance in healthy and myosin-deficient fly hearts. Moreover, cardiac-specific vinculin overexpression increased median life span by more than 150% in flies. A broad array of potential therapeutic targets and regulators of age-associated modifications, specifically for vinculin, are presented. These findings suggest that the heart has molecular mechanisms to sustain performance and promote longevity, which may be assisted by therapeutic intervention to ameliorate the decline of function in aging patient hearts.
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Affiliation(s)
- Gaurav Kaushik
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Alice Spenlehauer
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ayla O Sessions
- Biomedical Sciences Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Adriana S Trujillo
- Department of Biology, Heart Institute, and Molecular Biology Institute, San Diego State University, San Diego, CA 92182, USA
| | - Alexander Fuhrmann
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zongming Fu
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Vidya Venkatraman
- Advanced Clinical Biosystems Research Institute, Barbra Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Danielle Pohl
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jeremy Tuler
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mingyi Wang
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Karen Ocorr
- Development and Aging Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Rolf Bodmer
- Development and Aging Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Sanford I Bernstein
- Department of Biology, Heart Institute, and Molecular Biology Institute, San Diego State University, San Diego, CA 92182, USA
| | - Jennifer E Van Eyk
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA. Advanced Clinical Biosystems Research Institute, Barbra Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
| | - Adam J Engler
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA. Biomedical Sciences Program, University of California, San Diego, La Jolla, CA 92093, USA. Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037, USA.
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Mu Y, Jing R, Peter AK, Lange S, Lin L, Zhang J, Ouyang K, Fang X, Veevers J, Zhou X, Evans SM, Cheng H, Chen J. Cypher and Enigma homolog protein are essential for cardiac development and embryonic survival. J Am Heart Assoc 2015; 4:jah3966. [PMID: 25944877 PMCID: PMC4599425 DOI: 10.1161/jaha.115.001950] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background The striated muscle Z-line, a multiprotein complex at the boundary between sarcomeres, plays an integral role in maintaining striated muscle structure and function. Multiple Z-line-associated proteins have been identified and shown to play an increasingly important role in the pathogenesis of human cardiomyopathy. Cypher and its close homologue, Enigma homolog protein (ENH), are 2 Z-line proteins previously shown to be individually essential for maintenance of postnatal cardiac function and stability of the Z-line during muscle contraction, but dispensable for cardiac myofibrillogenesis and development. Methods and Results The current studies were designed to test whether Cypher and ENH play redundant roles during embryonic development. Here, we demonstrated that mice lacking both ENH and Cypher exhibited embryonic lethality and growth retardation. Lethality in double knockout embryos was associated with cardiac dilation and abnormal Z-line structure. In addition, when ENH was ablated in conjunction with selective ablation of either Cypher short isoforms (CypherS), or Cypher long isoforms (CypherL), only the latter resulted in embryonic lethality. Conclusions Cypher and ENH redundantly play an essential role in sustaining Z-line structure from the earliest stages of cardiac function, and are redundantly required to maintain normal embryonic heart function and embryonic viability.
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Affiliation(s)
- Yongxin Mu
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.)
| | - Ran Jing
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.) Xiangya Hospital, Central South University, Changsha, China (R.J., X.Z.)
| | - Angela K Peter
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.)
| | - Stephan Lange
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.)
| | - Lizhu Lin
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.) Department of Medicine, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA (L.L., S.M.E.)
| | - Jianlin Zhang
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.)
| | - Kunfu Ouyang
- Key Laboratory of Chemical Genomics, Drug Discovery Center, Peking University Shenzhen Graduate School, Shenzhen, China (K.O.)
| | - Xi Fang
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.)
| | - Jennifer Veevers
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.)
| | - Xinmin Zhou
- Xiangya Hospital, Central South University, Changsha, China (R.J., X.Z.)
| | - Sylvia M Evans
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.) Department of Medicine, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA (L.L., S.M.E.)
| | - Hongqiang Cheng
- Department of Pathology and Pathophysiology, Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, China (H.C.)
| | - Ju Chen
- Department of Medicine, University of California San Diego, La Jolla, CA (Y.M., R.J., A.K.P., S.L., L.L., J.Z., X.F., J.V., S.M.E., J.C.)
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Yang J, Shih YH, Xu X. Understanding cardiac sarcomere assembly with zebrafish genetics. Anat Rec (Hoboken) 2015; 297:1681-93. [PMID: 25125181 DOI: 10.1002/ar.22975] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 05/12/2014] [Accepted: 05/13/2014] [Indexed: 01/06/2023]
Abstract
Mutations in sarcomere genes have been found in many inheritable human diseases, including hypertrophic cardiomyopathy. Elucidating the molecular mechanisms of sarcomere assembly shall facilitate understanding of the pathogenesis of sarcomere-based cardiac disease. Recently, biochemical and genomic studies have identified many new genes encoding proteins that localize to the sarcomere. However, their precise functions in sarcomere assembly and sarcomere-based cardiac disease are unknown. Here, we review zebrafish as an emerging vertebrate model for these studies. We summarize the techniques offered by this animal model to manipulate genes of interest, annotate gene expression, and describe the resulting phenotypes. We survey the sarcomere genes that have been investigated in zebrafish and discuss the potential of applying this in vivo model for larger-scale genetic studies.
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Affiliation(s)
- Jingchun Yang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota; Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota
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The sarcomeric M-region: a molecular command center for diverse cellular processes. BIOMED RESEARCH INTERNATIONAL 2015; 2015:714197. [PMID: 25961035 PMCID: PMC4413555 DOI: 10.1155/2015/714197] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/08/2015] [Indexed: 02/07/2023]
Abstract
The sarcomeric M-region anchors thick filaments and withstands the mechanical stress of contractions by deformation, thus enabling distribution of physiological forces along the length of thick filaments. While the role of the M-region in supporting myofibrillar structure and contractility is well established, its role in mediating additional cellular processes has only recently started to emerge. As such, M-region is the hub of key protein players contributing to cytoskeletal remodeling, signal transduction, mechanosensing, metabolism, and proteasomal degradation. Mutations in genes encoding M-region related proteins lead to development of severe and lethal cardiac and skeletal myopathies affecting mankind. Herein, we describe the main cellular processes taking place at the M-region, other than thick filament assembly, and discuss human myopathies associated with mutant or truncated M-region proteins.
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Lyon RC, Zanella F, Omens JH, Sheikh F. Mechanotransduction in cardiac hypertrophy and failure. Circ Res 2015; 116:1462-1476. [PMID: 25858069 PMCID: PMC4394185 DOI: 10.1161/circresaha.116.304937] [Citation(s) in RCA: 237] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/13/2015] [Indexed: 01/10/2023]
Abstract
Cardiac muscle cells have an intrinsic ability to sense and respond to mechanical load through a process known as mechanotransduction. In the heart, this process involves the conversion of mechanical stimuli into biochemical events that induce changes in myocardial structure and function. Mechanotransduction and its downstream effects function initially as adaptive responses that serve as compensatory mechanisms during adaptation to the initial load. However, under prolonged and abnormal loading conditions, the remodeling processes can become maladaptive, leading to altered physiological function and the development of pathological cardiac hypertrophy and heart failure. Although the mechanisms underlying mechanotransduction are far from being fully elucidated, human and mouse genetic studies have highlighted various cytoskeletal and sarcolemmal structures in cardiac myocytes as the likely candidates for load transducers, based on their link to signaling molecules and architectural components important in disease pathogenesis. In this review, we summarize recent developments that have uncovered specific protein complexes linked to mechanotransduction and mechanotransmission within the sarcomere, the intercalated disc, and at the sarcolemma. The protein structures acting as mechanotransducers are the first step in the process that drives physiological and pathological cardiac hypertrophy and remodeling, as well as the transition to heart failure, and may provide better insights into mechanisms driving mechanotransduction-based diseases.
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Affiliation(s)
- Robert C. Lyon
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Fabian Zanella
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Jeffrey H. Omens
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
- Department of Bioengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Farah Sheikh
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
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69
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Jasnic-Savovic J, Nestorovic A, Savic S, Karasek S, Vitulo N, Valle G, Faulkner G, Radojkovic D, Kojic S. Profiling of skeletal muscle Ankrd2 protein in human cardiac tissue and neonatal rat cardiomyocytes. Histochem Cell Biol 2015; 143:583-97. [PMID: 25585647 DOI: 10.1007/s00418-015-1307-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/26/2014] [Indexed: 10/24/2022]
Abstract
Muscle-specific mechanosensors Ankrd2/Arpp (ankyrin repeat protein 2) and Ankrd1/CARP (cardiac ankyrin repeat protein) have an important role in transcriptional regulation, myofibrillar assembly, cardiogenesis and myogenesis. In skeletal muscle myofibrils, Ankrd2 has a structural role as a component of a titin associated stretch-sensing complex, while in the nucleus it exerts regulatory function as transcriptional co-factor. It is also involved in myogenic differentiation and coordination of myoblast proliferation. Although expressed in the heart, the role of Ankrd2 in the cardiac muscle is completely unknown. Recently, we have shown that hypertrophic and dilated cardiomyopathy pathways are altered upon Ankrd2 silencing suggesting the importance of this protein in cardiac tissue. Here we provide the underlying basis for the functional investigation of Ankrd2 in the heart. We confirmed reduced Ankrd2 expression levels in human heart in comparison with Ankrd1 using RNAseq and Western blot. For the first time we demonstrated that, apart from the sarcomere and nucleus, both proteins are localized to the intercalated disks of human cardiomyocytes. We further tested the expression and localization of endogenous Ankrd2 in rat neonatal cardiomyocytes, a well-established model for studying cardiac-specific proteins. Ankrd2 was found to be expressed in both the cytoplasm and nucleus, independently from maturation status of cardiomyocytes. In contrast to Ankrd1, it is not responsive to the cardiotoxic drug Doxorubicin, suggesting that different mechanisms govern their expression in cardiac cells.
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Affiliation(s)
- Jovana Jasnic-Savovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, PO Box 23, 11010, Belgrade, Serbia
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71
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Youtz DJ, Isfort MC, Eichenseer CM, Nelin TD, Wold LE. In vitro effects of exercise on the heart. Life Sci 2014; 116:67-73. [PMID: 25218762 DOI: 10.1016/j.lfs.2014.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 08/21/2014] [Accepted: 08/23/2014] [Indexed: 12/28/2022]
Abstract
Pathologic and physiologic factors acting on the heart can produce consistent pressure changes, volume overload, or increased cardiac output. These changes may then lead to cardiac remodeling, ultimately resulting in cardiac hypertrophy. Exercise can also induce hypertrophy, primarily physiologic in nature. To determine the mechanisms responsible for each type of remodeling, it is important to examine the heart at the functional unit, the cardiomyocyte. Tests of individual cardiomyocyte function in vitro provide a deeper understanding of the changes occurring within the heart during hypertrophy. Examination of cardiomyocyte function during exercise primarily follows one of two pathways: the addition of hypertrophic inducing agents in vitro to normal cardiomyocytes, or the use of trained animal models and isolating cells following the development of hypertrophy in vivo. Due to the short lifespan of adult cardiomyocytes, a proportionately scant amount of research exists involving the direct stimulation of cells in vitro to induce hypertrophy. These attempts provide the only current evidence, as it is difficult to gather extensive data demonstrating cell growth as a result of in vitro physical stimulation. Researchers have created ways to combine skeletal myocytes with cardiomyocytes to produce functional muscle cells used to repair pathologic heart tissue, but continue to struggle with the short lifespan of these cells. While there have been promising findings regarding the mechanisms that surround cardiac hypertrophy in vitro, the translation of in vitro findings to in vivo function is not consistent. Therefore, the focus of this review is to highlight recent studies that have investigated the effect of exercise on the heart, both in vitro and in vivo.
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Affiliation(s)
- Dane J Youtz
- College of Nursing, The Ohio State University, Columbus, OH, USA
| | - Michael C Isfort
- College of Medicine, The Ohio State University, Columbus, OH, USA
| | | | - Timothy D Nelin
- College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Loren E Wold
- College of Nursing, The Ohio State University, Columbus, OH, USA; College of Medicine, The Ohio State University, Columbus, OH, USA; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA; Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, USA.
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Macaluso F, Isaacs AW, Di Felice V, Myburgh KH. Acute change of titin at mid-sarcomere remains despite 8 wk of plyometric training. J Appl Physiol (1985) 2014; 116:1512-9. [DOI: 10.1152/japplphysiol.00420.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to investigate skeletal muscle changes induced by an acute bout of plyometric exercise (PlyEx) both before and after PlyEx training, to understand if titin is affected differently after PlyEx training. Healthy untrained individuals ( N = 11) completed the 1stPlyEx (10 × 10 squat-jumps, 1-min rest). Thereafter, six subjects completed 8 wk of PlyEx, while five controls abstained from any jumping activity. Seven days after the last training session, all subjects completed the 2ndPlyEx. Blood samples were collected before and 6 h and 1, 2, 3, and 4 days after each acute bout of PlyEx, and muscle biopsies 4 days before and 3 days after each acute bout of PlyEx. The 1stPlyEx induced an increase in circulating myoglobin concentration. Muscle sample analysis revealed Z-disk streaming, a stretch or a fragmentation of titin (immunogold), and increased calpain-3 autolysis. After training, 2ndPlyEx did not induce Z-disk streaming or calpain-3 activation. The previously observed post-1stPlyEx positional change of the titin COOH terminus was still present pre-2ndPlyEx, in all trained and all control subjects. Only two controls presented with Z-disk streaming after 2ndPlyEx, while calpain-3 activation was absent in all controls. Eccentric explosive exercise induced a stretch or fragmentation of titin, which presented as a positional change of the COOH terminus. Calpain-3 activation does not occur when titin is already stretched before explosive jumping. Enzymatic digestion results in titin fragmentation, but since an increase in calpain-3 autolysis was visible only after the 1stPlyEx acute bout, fragmentation cannot explain the prolonged positional change.
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Affiliation(s)
- F. Macaluso
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa; and
- Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche, Università di Palermo, Palermo, Italy
| | - A. W. Isaacs
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa; and
| | - V. Di Felice
- Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche, Università di Palermo, Palermo, Italy
| | - K. H. Myburgh
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa; and
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Zacchigna S, Giacca M. Extra- and intracellular factors regulating cardiomyocyte proliferation in postnatal life. Cardiovasc Res 2014; 102:312-20. [PMID: 24623280 DOI: 10.1093/cvr/cvu057] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
One of the striking differences that distinguish the adult from the embryonic heart in mammals and set it apart from the heart in urodeles and teleosts is the incapacity of cardiomyocytes to respond to damage by proliferation. While the molecular reasons underlying these characteristics still await elucidation, mounting evidence collected over the last several years indicates that cardiomyocyte proliferation can be modulated by different extracellular molecules. The exogenous administration of selected growth factors is capable of inducing neonatal and, in some instances, also adult cardiomyocyte proliferation. Other diffusible factors can regulate the proliferation and cardiac commitment of endogenous or implanted stem cells. While the individual role of these factors in the paracrine control of normal heart homeostasis still needs to be defined, this information is relevant for the development of novel therapeutic strategies for cardiac regeneration. In addition, recent evidence indicates that postnatal cardiomyocyte proliferation is controlled by genetically defined pathways, such as the Hippo pathway, and can be modulated by perturbing the endogenous cardiomyocyte microRNA network; the identification of the cytokines that activate these molecular circuits holds great potential for clinical translation.
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Affiliation(s)
- Serena Zacchigna
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology , Padriciano, 99, Trieste 34149, Italy
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Lamon S, Wallace MA, Russell AP. The STARS signaling pathway: a key regulator of skeletal muscle function. Pflugers Arch 2014; 466:1659-71. [DOI: 10.1007/s00424-014-1475-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 01/08/2023]
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Prasad V, Lorenz JN, Lasko VM, Nieman ML, Al Moamen NJ, Shull GE. Loss of the AE3 Cl(-)/HCO(-) 3 exchanger in mice affects rate-dependent inotropy and stress-related AKT signaling in heart. Front Physiol 2013; 4:399. [PMID: 24427143 PMCID: PMC3875869 DOI: 10.3389/fphys.2013.00399] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 12/19/2013] [Indexed: 01/12/2023] Open
Abstract
Cl(-)/HCO(-) 3 exchangers are expressed abundantly in cardiac muscle, suggesting that HCO(-) 3 extrusion serves an important function in heart. Mice lacking Anion Exchanger Isoform 3 (AE3), a major cardiac Cl(-)/HCO(-) 3 exchanger, appear healthy, but loss of AE3 causes decompensation in a hypertrophic cardiomyopathy (HCM) model. Using intra-ventricular pressure analysis, in vivo pacing, and molecular studies we identified physiological and biochemical changes caused by loss of AE3 that may contribute to decompensation in HCM. AE3-null mice had normal cardiac contractility under basal conditions and after β-adrenergic stimulation, but pacing of hearts revealed that frequency-dependent inotropy was blunted, suggesting that AE3-mediated HCO(-) 3 extrusion is required for a robust force-frequency response (FFR) during acute biomechanical stress in vivo. Modest changes in expression of proteins that affect Ca(2+)-handling were observed, but Ca(2+)-transient analysis of AE3-null myocytes showed normal twitch-amplitude and Ca(2+)-clearance. Phosphorylation and expression of several proteins implicated in HCM and FFR, including phospholamban (PLN), myosin binding protein C, and troponin I were not altered in hearts of paced AE3-null mice; however, phosphorylation of Akt, which plays a central role in mechanosensory signaling, was significantly higher in paced AE3-null hearts than in wild-type controls and phosphorylation of AMPK, which is affected by Akt and is involved in energy metabolism and some cases of HCM, was reduced. These data show loss of AE3 leads to impaired rate-dependent inotropy, appears to affect mechanical stress-responsive signaling, and reduces activation of AMPK, which may contribute to decompensation in heart failure.
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Affiliation(s)
- Vikram Prasad
- Departments of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - John N Lorenz
- Departments of Cellular and Molecular Physiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - Valerie M Lasko
- Departments of Cellular and Molecular Physiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - Michelle L Nieman
- Departments of Cellular and Molecular Physiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - Nabeel J Al Moamen
- Genetic Laboratory, Department of Pathology, Salmaniya Medical Complex Manama, Bahrain
| | - Gary E Shull
- Departments of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
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Abstract
Morphogenesis is the remarkable process by which cells self-assemble into complex tissues and organs that exhibit specialized form and function during embryological development. Many of the genes and chemical cues that mediate tissue and organ formation have been identified; however, these signals alone are not sufficient to explain how tissues and organs are constructed that exhibit their unique material properties and three-dimensional forms. Here, we review work that has revealed the central role that physical forces and extracellular matrix mechanics play in the control of cell fate switching, pattern formation, and tissue development in the embryo and how these same mechanical signals contribute to tissue homeostasis and developmental control throughout adult life.
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Affiliation(s)
- Tadanori Mammoto
- Vascular Biology Program, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115;
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Transcriptional networks regulating the costamere, sarcomere, and other cytoskeletal structures in striated muscle. Cell Mol Life Sci 2013; 71:1641-56. [PMID: 24218011 DOI: 10.1007/s00018-013-1512-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/27/2013] [Accepted: 10/30/2013] [Indexed: 10/26/2022]
Abstract
Structural abnormalities in striated muscle have been observed in numerous transcription factor gain- and loss-of-function phenotypes in animal and cell culture model systems, indicating that transcription is important in regulating the cytoarchitecture. While most characterized cytoarchitectural defects are largely indistinguishable by histological and ultrastructural criteria, analysis of dysregulated gene expression in each mutant phenotype has yielded valuable information regarding specific structural gene programs that may be uniquely controlled by each of these transcription factors. Linking the formation and maintenance of each subcellular structure or subset of proteins within a cytoskeletal compartment to an overlapping but distinct transcription factor cohort may enable striated muscle to control cytoarchitectural function in an efficient and specific manner. Here we summarize the available evidence that connects transcription factors, those with established roles in striated muscle such as MEF2 and SRF, as well as other non-muscle transcription factors, to the regulation of a defined cytoskeletal structure. The notion that genes encoding proteins localized to the same subcellular compartment are coordinately transcriptionally regulated may prompt rationally designed approaches that target specific transcription factor pathways to correct structural defects in muscle disease.
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78
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Expression and localization of TRPC proteins in rat ventricular myocytes at various developmental stages. Cell Tissue Res 2013; 355:201-12. [PMID: 24146259 DOI: 10.1007/s00441-013-1733-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 09/02/2013] [Indexed: 12/22/2022]
Abstract
Growing evidence indicates that transient receptor potential canonical (TRPC) channels play important roles in various Ca(2+)-mediated physiological and pathophysiological processes, including development. Many types of TRPC proteins are expressed in the heart. However, limited data are available comparing the expression and localization among TRPC proteins in the ventricular myocyte at various developmental stages. Our purpose is to investigate the expression and localization profile of TRPC proteins in ventricular myocytes of fetal (18.5 days), neonatal (< 24 h after birth) and adult (8 week old) rats. Western blotting, immunofluorescence and confocal laser scanning microscopy were employed. TRPC1/3-6 proteins were expressed in the rat ventricle throughout the three developmental stages. The expression profile of TRPC1/3/4 in the ventricle followed an upward trend from the fetus to the adult. By contrast, TRPC6 in the ventricle was expressed at the highest level in the fetal group and was sharply down-regulated immediately after birth. TRPC5 expression in the ventricle did not change significantly during the three stages. TRPC1/3/5/6 proteins were localized to the T-tubule and TRPC1/3/4/6 to intercalated disks in adult myocytes. The wide spatiotemporal overlap and dynamic regulation of TRPC expression in ventricular myocytes indicates potential complex combinations and redundancy of native TRPC proteins in the heart and gives important clues for further investigations into the exact subunit compositions and functional properties of native TRPC channels in the heart.
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79
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Chang YW, Chang YT, Wang Q, Lin JJC, Chen YJ, Chen CC. Quantitative phosphoproteomic study of pressure-overloaded mouse heart reveals dynamin-related protein 1 as a modulator of cardiac hypertrophy. Mol Cell Proteomics 2013; 12:3094-107. [PMID: 23882026 DOI: 10.1074/mcp.m113.027649] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Pressure-overload stress to the heart causes pathological cardiac hypertrophy, which increases the risk of cardiac morbidity and mortality. However, the detailed signaling pathways induced by pressure overload remain unclear. Here we used phosphoproteomics to delineate signaling pathways in the myocardium responding to acute pressure overload and chronic hypertrophy in mice. Myocardial samples at 4 time points (10, 30, 60 min and 2 weeks) after transverse aortic banding (TAB) in mice underwent quantitative phosphoproteomics assay. Temporal phosphoproteomics profiles showed 360 phosphorylation sites with significant regulation after TAB. Multiple mechanical stress sensors were activated after acute pressure overload. Gene ontology analysis revealed differential phosphorylation between hearts with acute pressure overload and chronic hypertrophy. Most interestingly, analysis of the cardiac hypertrophy pathway revealed phosphorylation of the mitochondrial fission protein dynamin-related protein 1 (DRP1) by prohypertrophic kinases. Phosphorylation of DRP1 S622 was confirmed in TAB-treated mouse hearts and phenylephrine (PE)-treated rat neonatal cardiomyocytes. TAB-treated mouse hearts showed phosphorylation-mediated mitochondrial translocation of DRP1. Inhibition of DRP1 with the small-molecule inhibitor mdivi-1 reduced the TAB-induced hypertrophic responses. Mdivi-1 also prevented PE-induced hypertrophic growth and oxygen consumption in rat neonatal cardiomyocytes. We reveal the signaling responses of the heart to pressure stress in vivo and in vitro. DRP1 may be important in the development of cardiac hypertrophy.
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Affiliation(s)
- Yu-Wang Chang
- Molecular Medicine Program, Taiwan International Graduate Program, Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
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80
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Vikhlyantsev IM, Podlubnaya ZA. New titin (connectin) isoforms and their functional role in striated muscles of mammals: facts and suppositions. BIOCHEMISTRY (MOSCOW) 2013; 77:1515-35. [PMID: 23379526 DOI: 10.1134/s0006297912130093] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This review summarizes results of our studies on titin isoform composition in vertebrate striated muscles under normal conditions, during hibernation, real and simulated microgravity, and under pathological conditions (stiff-person syndrome, post-apoplectic spasticity, dilated cardiomyopathy, cardiac hypertrophy). Experimental evidence for the existence in mammalian striated muscles of higher molecular weight isoforms of titin (NT-isoforms) in addition to the known N2A-, N2BA-, and N2B-titin isoforms was obtained. Comparative studies of changes in titin isoform composition and structure-functional properties of human and animal striated muscles during adaptive and pathological processes led to a conclusion about the key role of NT-isoforms of titin in maintenance of sarcomere structure and contractile function of these muscles.
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Affiliation(s)
- I M Vikhlyantsev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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81
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Monasky MM, Taglieri DM, Jacobson AK, Haizlip KM, Solaro RJ, Janssen PM. Post-translational modifications of myofilament proteins involved in length-dependent prolongation of relaxation in rabbit right ventricular myocardium. Arch Biochem Biophys 2013; 535:22-9. [PMID: 23085150 PMCID: PMC3640662 DOI: 10.1016/j.abb.2012.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/02/2012] [Accepted: 10/10/2012] [Indexed: 12/27/2022]
Abstract
The phosphorylation state of several cardiac myofilament proteins changes with the level of stretch in intact, twitch-contracting cardiac muscles. It remains unclear which kinases are involved in the length-dependent phosphorylation of these proteins. We set out to investigate which kinases are involved after a step-wise change in cardiac muscle length. We hypothesize that myofilament protein phosphorylation by PKCβII and PKA alters contractile kinetics during length-dependent activation. Right ventricular intact trabeculae were isolated from New Zealand White rabbit hearts and stimulated to contract at 1Hz. Twitch force recordings where taken at taut and optimal muscle lengths before and after administration of kinase inhibitors at 37°C. PKCβII inhibition significantly decreased time from stimulation to peak force (TTP), time from peak force to 50% relaxation (RT50), and 90% relaxation (RT90) at optimal muscle length. This led to a loss in the length-dependent increase of RT50 and RT90 in the presence of the PKCβII inhibitor, whereas the length-dependent increase in RT50 and RT90 was seen in the controls. PKA inhibition using H-89 significantly decreased TTP at both taut and optimal muscle lengths. Detection of Ser/Thr phosphorylation with ProQ-diamond staining indicates a role for PKCβII in the phosphorylation of tropomyosin and myosin light chain-2 (MLC2) and PKA for tropomyosin, troponin-I, MLC2, myosin binding protein-C, troponin-T (TnT) 3 and TnT4. Our data provide evidence for two signaling kinases acting upon myofilament proteins during length-dependent activation, and provide further insight for length-dependent myofilament function.
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Affiliation(s)
- Michelle M. Monasky
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Avenue (M/C 901), Chicago, IL 60612-7342, USA
| | - Domenico M. Taglieri
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Avenue (M/C 901), Chicago, IL 60612-7342, USA
| | - Alice K. Jacobson
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Kaylan M. Haizlip
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - R. John Solaro
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Avenue (M/C 901), Chicago, IL 60612-7342, USA
| | - Paul M.L. Janssen
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
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Di Felice V, Serradifalco C, Rizzuto L, De Luca A, Rappa F, Barone R, Di Marco P, Cassata G, Puleio R, Verin L, Motta A, Migliaresi C, Guercio A, Zummo G. Silk fibroin scaffolds enhance cell commitment of adult rat cardiac progenitor cells. J Tissue Eng Regen Med 2013; 9:E51-64. [PMID: 23592297 DOI: 10.1002/term.1739] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Revised: 01/18/2013] [Accepted: 02/05/2013] [Indexed: 01/30/2023]
Abstract
The use of three-dimensional (3D) cultures may induce cardiac progenitor cells to synthesize their own extracellular matrix (ECM) and sarcomeric proteins to initiate cardiac differentiation. 3D cultures grown on synthetic scaffolds may favour the implantation and survival of stem cells for cell therapy when pharmacological therapies are not efficient in curing cardiovascular diseases and when organ transplantation remains the only treatment able to rescue the patient's life. Silk fibroin-based scaffolds may be used to increase cell affinity to biomaterials and may be chemically modified to improve cell adhesion. In the present study, porous, partially orientated and electrospun nanometric nets were used. Cardiac progenitor cells isolated from adult rats were seeded by capillarity in the 3D structures and cultured inside inserts for 21 days. Under this condition, the cells expressed a high level of sarcomeric and cardiac proteins and synthesized a great quantity of ECM. In particular, partially orientated scaffolds induced the synthesis of titin, which is a fundamental protein in sarcomere assembly.
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Affiliation(s)
- Valentina Di Felice
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy
| | - Claudia Serradifalco
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy
| | - Luigi Rizzuto
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy
| | - Angela De Luca
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy
| | - Francesca Rappa
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy
| | - Rosario Barone
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy
| | | | - Giovanni Cassata
- Istituto Zooprofilattico Sperimentale della Sicilia, Palermo, Italy
| | - Roberto Puleio
- Istituto Zooprofilattico Sperimentale della Sicilia, Palermo, Italy
| | - Lucia Verin
- Department of Materials Engineering and Industrial Technologies and Biotech Research Centre, University of Trento, Italy
- European Institute of Excellence in Tissue Engineering and Regenerative Medicine and INSTM Research Unit, Trento, Italy
| | - Antonella Motta
- Department of Materials Engineering and Industrial Technologies and Biotech Research Centre, University of Trento, Italy
- European Institute of Excellence in Tissue Engineering and Regenerative Medicine and INSTM Research Unit, Trento, Italy
| | - Claudio Migliaresi
- Department of Materials Engineering and Industrial Technologies and Biotech Research Centre, University of Trento, Italy
- European Institute of Excellence in Tissue Engineering and Regenerative Medicine and INSTM Research Unit, Trento, Italy
| | - Annalisa Guercio
- Istituto Zooprofilattico Sperimentale della Sicilia, Palermo, Italy
| | - Giovanni Zummo
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy
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83
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Willis MS, Wadosky KM, Rodríguez JE, Schisler JC, Lockyer P, Hilliard EG, Glass DJ, Patterson C. Muscle ring finger 1 and muscle ring finger 2 are necessary but functionally redundant during developmental cardiac growth and regulate E2F1-mediated gene expression in vivo. Cell Biochem Funct 2013; 32:39-50. [PMID: 23512667 DOI: 10.1002/cbf.2969] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 02/03/2013] [Accepted: 02/14/2013] [Indexed: 12/12/2022]
Abstract
AIMS Muscle ring finger (MuRF) proteins have been implicated in the transmission of mechanical forces to nuclear cell signaling pathways through their association with the sarcomere. We recently reported that MuRF1, but not MuRF2, regulates pathologic cardiac hypertrophy in vivo. This was surprising given that MuRF1 and MuRF2 interact with each other and many of the same sarcomeric proteins experimentally. METHODS AND RESULTS Mice missing all four MuRF1 and MuRF2 alleles [MuRF1/MuRF2 double null (DN)] were born with a massive spontaneous hypertrophic cardiomyopathy and heart failure; mice that were null for one of the genes but heterozygous for the other (i.e. MuRF1(-/-) //MuRF2(+/-) or MuRF1(+/-) //MuRF2(-/-) ) were phenotypically identical to wild-type mice. Microarray analysis of genes differentially-expressed between MuRF1/MuRF2 DN, mice missing three of the four alleles and wild-type mice revealed a significant enrichment of genes regulated by the E2F transcription factor family. More than 85% of the differentially-expressed genes had E2F promoter regions (E2f:DP; P<0.001). Western analysis of E2F revealed no differences between MuRF1/MuRF2 DN hearts and wild-type hearts; however, chromatin immunoprecipitation studies revealed that MuRF1/MuRF2 DN hearts had significantly less binding of E2F1 in the promoter regions of genes previously defined to be regulated by E2F1 (p21, Brip1 and PDK4, P<0.01). CONCLUSIONS These studies suggest that MuRF1 and MuRF2 play a redundant role in regulating developmental physiologic hypertrophy, by regulating E2F transcription factors essential for normal cardiac development by supporting E2F localization to the nucleus, but not through a process that degrades the transcription factor.
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Affiliation(s)
- Monte S Willis
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA; Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC, USA
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84
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Abstract
We focus here on the modulation of thin filament activity by cardiac troponin I phosphorylation as an integral and adaptive mechanism in cardiac homeostasis and as a mechanism vulnerable to maladaptive response to stress. We discuss a current concept of cardiac troponin I function in the A-band region of the sarcomere and potential signaling to cardiac troponin I in a network involving the ends of the thin filaments at the Z-disk and the M-band regions. The cardiac sarcomere represents a remarkable set of interacting proteins that functions not only as a molecular machine generating the heartbeat but also as a hub of signaling. We review how phosphorylation signaling to cardiac troponin I is integrated, with parallel signals controlling excitation-contraction coupling, hypertrophy, and metabolism.
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Affiliation(s)
- R John Solaro
- Department of Physiology and Biophysics and Center for Cardiovascular Research, University of Illinois at Chicago, College of Medicine, Chicago, IL 60612, USA.
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85
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Biophysical Forces Modulate the Costamere and Z-Disc for Sarcomere Remodeling in Heart Failure. BIOPHYSICS OF THE FAILING HEART 2013. [DOI: 10.1007/978-1-4614-7678-8_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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86
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Okamoto R, Li Y, Noma K, Hiroi Y, Liu PY, Taniguchi M, Ito M, Liao JK. FHL2 prevents cardiac hypertrophy in mice with cardiac-specific deletion of ROCK2. FASEB J 2012; 27:1439-49. [PMID: 23271052 DOI: 10.1096/fj.12-217018] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The Rho-associated coiled-coil containing kinases, ROCK1 and ROCK2, are important regulators of cell shape, migration, and proliferation through effects on the actin cytoskeleton. However, it is not known whether ROCK2 plays an important role in the development of cardiac hypertrophy. To determine whether the loss of ROCK2 could prevent cardiac hypertrophy, cardiomyocyte-specific ROCK2-null (c-ROCK2(-/-)) were generated using conditional ROCK2(flox/flox) mice and α-myosin heavy-chain promoter-driven Cre recombinase transgenic mice. Cardiac hypertrophy was induced by Ang II infusion (400 ng/kg/min, 28 d) or transverse aortic constriction (TAC). Under basal conditions, hemodynamic parameters, cardiac anatomy, and function of c-ROCK2(-/-) mice were comparable to wild-type (WT) mice. However, following Ang II infusion or TAC, c-ROCK2(-/-) mice exhibited a substantially smaller increase in heart-to-body weight ratio, left ventricular mass, myocyte cross-sectional area, hypertrophy-related fetal gene expression, intraventricular fibrosis, cardiac apoptosis, and oxidative stress compared to control mice. Deletion of ROCK2 in cardiomyocytes leads to increased expression of four-and-a-half LIM-only protein-2 (FHL2) and FHL2-mediated inhibition of serum response factor (SRF) and extracellular signal-regulated mitogen-activated protein kinase (ERK). Knockdown of FHL2 expression in ROCK2-deficient cardiomyocytes or placing ROCK2-haploinsufficient (ROCK2(+/-)) mice on FHL2(+/-)-haploinsufficient background restored the hypertrophic response to Ang II. These results indicate that cardiomyocyte ROCK2 is essential for the development of cardiac hypertrophy and that up-regulation of FHL2 may contribute to the antihypertrophic phenotype that is observed in cardiac-specific ROCK2-deficient mice.
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Affiliation(s)
- Ryuji Okamoto
- Vascular Medicine Research Unit, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02139, USA
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87
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Substrate stiffness affects sarcomere and costamere structure and electrophysiological function of isolated adult cardiomyocytes. Cardiovasc Pathol 2012; 22:219-27. [PMID: 23266222 DOI: 10.1016/j.carpath.2012.10.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 10/16/2012] [Accepted: 10/16/2012] [Indexed: 12/31/2022] Open
Abstract
INTRODUCTION The mechanical environment is a key regulator of function in cardiomyocytes. We studied the role of substrate stiffness on the organization of sarcomeres and costameres in adult rat cardiomyocytes and further examined the resulting changes in cell shortening and calcium dynamics. METHODS Cardiomyocytes isolated from adult rats were plated on laminin-coated polydimethylsiloxane substrates of defined stiffness (255 kPa, 117 kPa, 27 kPa, and 7 kPa) for 48 h. Levels of α-actinin and β1 integrins were determined by immunofluoresence imaging and immunoblotting, both in the absence and presence of the phosphatase inhibitor calyculin A. Quantitative reverse transcriptase polymerase chain reaction was used to measure message levels of key structural proteins (α-actinin, α7 integrin, β1 integrin, vinculin). Sarcomere shortening and calcium dynamics were measured at 2, 24, and 48 h. RESULTS Overall cardiomyocyte morphology was similar on all substrates. However, well organized sarcomere structures were observed on only the stiffest (255 kPa) and the most compliant (7 kPa) substrates. Levels of α-actinin in cells were the same on all substrates, while message levels of structural proteins were up-regulated on substrates of intermediate stiffness. Inhibition of phosphatase activity blocked the degradation of contractile structures, but altered overall cardiomyocyte morphology. Shortening and calcium dynamics also were dependent on substrate stiffness; however, there was no clear causative relationship between the phenomena. CONCLUSIONS Extracellular matrix stiffness can affect structural remodeling by adult cardiomyocytes, and the resulting contractile activity. These findings illuminate changes in cardiomyocyte function in cardiac fibrosis, and may suggest cardiac-specific phosphatases as a target for therapeutic intervention.
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88
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Buffinton CM, Faas D, Sedmera D. Stress and strain adaptation in load-dependent remodeling of the embryonic left ventricle. Biomech Model Mechanobiol 2012; 12:1037-51. [PMID: 23254562 DOI: 10.1007/s10237-012-0461-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 12/03/2012] [Indexed: 01/01/2023]
Abstract
Altered pressure in the developing left ventricle (LV) results in altered morphology and tissue material properties. Mechanical stress and strain may play a role in the regulating process. This study showed that confocal microscopy, three-dimensional reconstruction, and finite element analysis can provide a detailed model of stress and strain in the trabeculated embryonic heart. The method was used to test the hypothesis that end-diastolic strains are normalized after altered loading of the LV during the stages of trabecular compaction and chamber formation. Stage-29 chick LVs subjected to pressure overload and underload at stage 21 were reconstructed with full trabecular morphology from confocal images and analyzed with finite element techniques. Measured material properties and intraventricular pressures were specified in the models. The results show volume-weighted end-diastolic von Mises stress and strain averaging 50-82 % higher in the trabecular tissue than in the compact wall. The volume-weighted-average stresses for the entire LV were 115, 64, and 147 Pa in control, underloaded, and overloaded models, while strains were 11, 7, and 4 %; thus, neither was normalized in a volume-weighted sense. Localized epicardial strains at mid-longitudinal level were similar among the three groups and to strains measured from high-resolution ultrasound images. Sensitivity analysis showed changes in material properties are more significant than changes in geometry in the overloaded strain adaptation, although resulting stress was similar in both types of adaptation. These results emphasize the importance of appropriate metrics and the role of trabecular tissue in evaluating the evolution of stress and strain in relation to pressure-induced adaptation.
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Affiliation(s)
- Christine M Buffinton
- Department of Mechanical Engineering, Bucknell University, One Dent Drive, Lewisburg, PA, 17837, USA,
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89
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Ablation of the cardiac-specific gene leucine-rich repeat containing 10 (Lrrc10) results in dilated cardiomyopathy. PLoS One 2012; 7:e51621. [PMID: 23236519 PMCID: PMC3517560 DOI: 10.1371/journal.pone.0051621] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 11/02/2012] [Indexed: 01/06/2023] Open
Abstract
Leucine-rich repeat containing 10 (LRRC10) is a cardiac-specific protein exclusively expressed in embryonic and adult cardiomyocytes. However, the role of LRRC10 in mammalian cardiac physiology remains unknown. To determine if LRRC10 is critical for cardiac function, Lrrc10-null (Lrrc10−/−) mice were analyzed. Lrrc10−/− mice exhibit prenatal systolic dysfunction and dilated cardiomyopathy in postnatal life. Importantly, Lrrc10−/− mice have diminished cardiac performance in utero, prior to ventricular dilation observed in young adults. We demonstrate that LRRC10 endogenously interacts with α-actinin and α-actin in the heart and all actin isoforms in vitro. Gene expression profiling of embryonic Lrrc10−/− hearts identified pathways and transcripts involved in regulation of the actin cytoskeleton to be significantly upregulated, implicating dysregulation of the actin cytoskeleton as an early defective molecular signal in the absence of LRRC10. In contrast, microarray analyses of adult Lrrc10−/− hearts identified upregulation of oxidative phosphorylation and cardiac muscle contraction pathways during the progression of dilated cardiomyopathy. Analyses of hypertrophic signal transduction pathways indicate increased active forms of Akt and PKCε in adult Lrrc10−/− hearts. Taken together, our data demonstrate that LRRC10 is essential for proper mammalian cardiac function. We identify Lrrc10 as a novel dilated cardiomyopathy candidate gene and the Lrrc10−/− mouse model as a unique system to investigate pediatric cardiomyopathy.
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90
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Abstract
The syncytium of cardiomyocytes in the heart is tethered within a matrix composed principally of type I fibrillar collagen. The matrix has diverse mechanical functions that ensure the optimal contractile efficiency of this muscular pump. In the diseased heart, cardiomyocytes are lost to necrotic cell death, and phenotypically transformed fibroblast-like cells-termed 'myofibroblasts'-are activated to initiate a 'reparative' fibrosis. The structural integrity of the myocardium is preserved by this scar tissue, although at the expense of its remodelled architecture, which has increased tissue stiffness and propensity to arrhythmias. A persisting population of activated myofibroblasts turns this fibrous tissue into a living 'secretome' that generates angiotensin II and its type 1 receptor, and fibrogenic growth factors (such as transforming growth factor-β), all of which collectively act as a signal-transducer-effector signalling pathway to type I collagen synthesis and, therefore, fibrosis. Persistent myofibroblasts, and the resultant fibrous tissue they produce, cause progressive adverse myocardial remodelling, a pathological hallmark of the failing heart irrespective of its etiologic origin. Herein, we review relevant cellular, subcellular, and molecular mechanisms integral to cardiac fibrosis and consequent remodelling of atria and ventricles with a heterogeneity in cardiomyocyte size. Signalling pathways that antagonize collagen fibrillogenesis provide novel strategies for cardioprotection.
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91
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Dynamic force sensing of filamin revealed in single-molecule experiments. Proc Natl Acad Sci U S A 2012; 109:19679-84. [PMID: 23150587 DOI: 10.1073/pnas.1211274109] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mechanical forces are important signals for cell response and development, but detailed molecular mechanisms of force sensing are largely unexplored. The cytoskeletal protein filamin is a key connecting element between the cytoskeleton and transmembrane complexes such as integrins or the von Willebrand receptor glycoprotein Ib. Here, we show using single-molecule mechanical measurements that the recently reported Ig domain pair 20-21 of human filamin A acts as an autoinhibited force-activatable mechanosensor. We developed a mechanical single-molecule competition assay that allows online observation of binding events of target peptides in solution to the strained domain pair. We find that filamin force sensing is a highly dynamic process occurring in rapid equilibrium that increases the affinity to the target peptides by up to a factor of 17 between 2 and 5 pN. The equilibrium mechanism we find here can offer a general scheme for cellular force sensing.
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92
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Dabiri BE, Lee H, Parker KK. A potential role for integrin signaling in mechanoelectrical feedback. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:196-203. [PMID: 22819851 DOI: 10.1016/j.pbiomolbio.2012.07.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 07/11/2012] [Indexed: 01/20/2023]
Abstract
Certain forms of heart disease involve gross morphological changes to the myocardium that alter its hemodynamic loading conditions. These changes can ultimately lead to the increased deposition of extracellular matrix (ECM) proteins, such as collagen and fibronectin, which together work to pathologically alter the myocardium's bulk tissue mechanics. In addition to changing the mechanical properties of the heart, this maladaptive remodeling gives rise to changes in myocardium electrical conductivity and synchrony since the tissue's mechanical properties are intimately tied to its electrical characteristics. This phenomenon, called mechanoelectrical coupling (MEC), can render individuals affected by heart disease arrhythmogenic and susceptible to Sudden Cardiac Death (SCD). The underlying mechanisms of MEC have been attributed to various processes, including the action of stretch activated channels and changes in troponin C-Ca(2+) binding affinity. However, changes in the heart post infarction or due to congenital myopathies are also accompanied by shifts in the expression of various molecular components of cardiomyocytes, including the mechanosensitive family of integrin proteins. As transmembrane proteins, integrins mechanically couple the ECM with the intracellular cytoskeleton and have been implicated in mediating ion homeostasis in various cell types, including neurons and smooth muscle. Given evidence of altered integrin expression in the setting of heart disease coupled with the associated increased risk for arrhythmia, we argue in this review that integrin signaling contributes to MEC. In light of the significant mortality associated with arrhythmia and SCD, close examination of all culpable mechanisms, including integrin-mediated MEC, is necessary.
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Affiliation(s)
- Borna E Dabiri
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard University, 29 Oxford St, Pierce Hall 321, Cambridge, MA 02138, USA
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Yang J, Xu X. α-Actinin2 is required for the lateral alignment of Z discs and ventricular chamber enlargement during zebrafish cardiogenesis. FASEB J 2012; 26:4230-42. [PMID: 22767232 DOI: 10.1096/fj.12-207969] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
α-Actinin2 (Actn2) is a predominant protein in the sarcomere Z disc whose mutation can lead to cardiomyopathy. However, the function of Actn2 in Z-disc assembly and cardiomyopathy in vertebrates remains elusive. We leveraged genetic tools in zebrafish embryos to elucidate the function of Actn2. We identified a single Actn2 homologue expressed in the zebrafish heart and conducted loss-of-function studies by antisense morpholino technology. Although zebrafish Actn2 assembles early into the Z disc, depletion of actn2 did not affect the early steps of sarcomere assembly. Instead, Actn2 is required for Z bodies to register laterally, forming well-aligned Z discs. Presumably as a consequence to this structural defect in the sarcomere, the depletion of Actn2 resulted in reduced cardiac function, primarily characterized as a reduced end-diastolic diameter. The depletion of actn2 also significantly reduced the ventricle chamber size, due to both reduced cardiomyocyte (CM) size and CM number. Interestingly, reduced CM size can be rescued by the cessation of heart contractions. The genetic studies of zebrafish uncovered a function for actn2 in lateral registration of Z body. In actn2 morphant fish, the Z-disc defect sequentially affects cardiac function, which leads to morphological changes in the ventricle through a mechanical force-dependent mechanism.
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Affiliation(s)
- Jingchun Yang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, 200 First St. SW, Rochester, MN 55905, USA
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Garcia de la Serrana D, Estévez A, Andree K, Johnston IA. Fast skeletal muscle transcriptome of the gilthead sea bream (Sparus aurata) determined by next generation sequencing. BMC Genomics 2012; 13:181. [PMID: 22577894 PMCID: PMC3418159 DOI: 10.1186/1471-2164-13-181] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 03/30/2012] [Indexed: 01/04/2023] Open
Abstract
Background The gilthead sea bream (Sparus aurata L.) occurs around the Mediterranean and along Eastern Atlantic coasts from Great Britain to Senegal. It is tolerant of a wide range of temperatures and salinities and is often found in brackish coastal lagoons and estuarine areas, particularly early in its life cycle. Gilthead sea bream are extensively cultivated in the Mediterranean with an annual production of 125,000 metric tonnes. Here we present a de novo assembly of the fast skeletal muscle transcriptome of gilthead sea bream using 454 reads and identify gene paralogues, splice variants and microsatellite repeats. An annotated transcriptome of the skeletal muscle will facilitate understanding of the genetic and molecular basis of traits linked to production in this economically important species. Results Around 2.7 million reads of mRNA sequence data were generated from the fast myotomal of adult fish (~2 kg) and juvenile fish (~0.09 kg) that had been either fed to satiation, fasted for 3-5d or transferred to low (11°C) or high (33°C) temperatures for 3-5d. Newbler v2.5 assembly resulted in 43,461 isotigs >100 bp. The number of sequences annotated by searching protein and gene ontology databases was 10,465. The average coverage of the annotated isotigs was x40 containing 5655 unique gene IDs and 785 full-length cDNAs coding for proteins containing 58–1536 amino acids. The v2.5 assembly was found to be of good quality based on validation using 200 full-length cDNAs from GenBank. Annotated isotigs from the reference transcriptome were attributable to 344 KEGG pathway maps. We identified 26 gene paralogues (20 of them teleost-specific) and 43 splice variants, of which 12 had functional domains missing that were likely to affect their biological function. Many key transcription factors, signaling molecules and structural proteins necessary for myogenesis and muscle growth have been identified. Physiological status affected the number of reads that mapped to isotigs, reflecting changes in gene expression between treatments. Conclusions We have produced a comprehensive fast skeletal muscle transcriptome for the gilthead sea bream, which will provide a resource for SNP discovery in genes with a large effect on production traits of commercial interest and for expression studies of growth and adaptation.
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Affiliation(s)
- Daniel Garcia de la Serrana
- Physiological and Evolutionary Genomics Laboratory, Scottish Oceans Institute, School of Biology, University of St Andrews, Fife, KY16 8LB, , Scotland, UK.
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95
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Arts T, Lumens J, Kroon W, Delhaas T. Control of whole heart geometry by intramyocardial mechano-feedback: a model study. PLoS Comput Biol 2012; 8:e1002369. [PMID: 22346742 PMCID: PMC3276542 DOI: 10.1371/journal.pcbi.1002369] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 12/19/2011] [Indexed: 01/19/2023] Open
Abstract
Geometry of the heart adapts to mechanical load, imposed by pressures and volumes of the cavities. We regarded preservation of cardiac geometry as a homeostatic control system. The control loop was simulated by a chain of models, starting with geometry of the cardiac walls, sequentially simulating circulation hemodynamics, myofiber stress and strain in the walls, transfer of mechano-sensed signals to structural changes of the myocardium, and finalized by calculation of resulting changes in cardiac wall geometry. Instead of modeling detailed mechano-transductive pathways and their interconnections, we used principles of control theory to find optimal transfer functions, representing the overall biological responses to mechanical signals. As biological responses we regarded tissue mass, extent of contractile myocyte structure and extent of the extra-cellular matrix. Mechano-structural stimulus-response characteristics were considered to be the same for atrial and ventricular tissue. Simulation of adaptation to self-generated hemodynamic load rendered physiologic geometry of all cardiac cavities automatically. Adaptation of geometry to chronic hypertension and volume load appeared also physiologic. Different combinations of mechano-sensors satisfied the condition that control of geometry is stable. Thus, we expect that for various species, evolution may have selected different solutions for mechano-adaptation. The heart is known to adapt size of the cavities and thickness of the walls to the pumping requirements set by blood pressure and blood flow. We think that mechanical load of the cardiac tissue provides feedback signals for adaptation of mass and thickness of the cardiac walls. Many cellular mechanisms are known where mechanical load initiates a cascade of chemical reactions, eventually affecting structure and mass of the tissue. Because these mechanisms interact intricately, understanding of the system of adaptation as a whole is tremendously complicated. We present a novel approach by considering adaptation as a control system. Using the principle that control should converge to a stable end state, general rules are found that should be satisfied on transfer of mechanical load to structural adaptation in the cells of the tissue. We think that deeper understanding of the mechanism of adaptation requires that knowledge on mechano-transductive pathways is placed in the context of regarding adaptation as a system. Knowledge on adaptation of cardiac geometry to mechanical load is crucial in predicting long term effects of pathologic disorders or therapeutic interventions that chronically affect blood pressure or blood flow.
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Affiliation(s)
- Theo Arts
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
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96
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β1 integrin gene excision in the adult murine cardiac myocyte causes defective mechanical and signaling responses. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:952-962. [PMID: 22248583 DOI: 10.1016/j.ajpath.2011.12.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 11/09/2011] [Accepted: 12/02/2011] [Indexed: 01/21/2023]
Abstract
How mechanical signals are transmitted in the cardiac myocyte is poorly understood. In this study, we produced a tamoxifen-inducible mouse model in which β1 integrin could be reduced specifically in the adult cardiomyocyte, so that the function of this integrin could be assessed in the postnatal and mechanically stressed heart. The expression of β1 integrin was reduced to 35% of control levels, but function remained normal at baseline. With aortic constriction, the knockout mice survived but had a blunted hypertrophic response. Integrin knockout myocytes, in contrast to controls, showed reduced integrin-linked kinase expression both at baseline and after hemodynamic stress; focal adhesion kinase expression was reduced after stress. Alterations in multiple signaling pathways were detected in the integrin knockout group after acute and chronic hemodynamic stress. Most remarkably, when we challenged the knockout mice with short-term loading, the robust responses of several kinases (extracellular signal-regulated kinase 1/2, p38, and Akt) evident in control mice were essentially abolished in the knockout mice. We also found that reduction of myocyte β1 integrin expression modified adrenergic-mediated signaling through extracellular signal-regulated kinase, p38, and Akt. Reduction of β1 integrin expression in the mature cardiac myocyte leads to a varied response compared with when this protein is reduced during either the embryonic or perinatal period. These results show that β1 integrin expression is required for proper mechanotransductive and adrenergic responses of the adult heart.
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97
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Li A, Ponten F, dos Remedios CG. The interactome of LIM domain proteins: The contributions of LIM domain proteins to heart failure and heart development. Proteomics 2012; 12:203-25. [DOI: 10.1002/pmic.201100492] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 11/07/2011] [Accepted: 11/08/2011] [Indexed: 12/22/2022]
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98
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Powell SR, Herrmann J, Lerman A, Patterson C, Wang X. The ubiquitin-proteasome system and cardiovascular disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 109:295-346. [PMID: 22727426 DOI: 10.1016/b978-0-12-397863-9.00009-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Over the past decade, the role of the ubiquitin-proteasome system (UPS) has been the subject of numerous studies to elucidate its role in cardiovascular physiology and pathophysiology. There have been many advances in this field including the use of proteomics to achieve a better understanding of how the cardiac proteasome is regulated. Moreover, improved methods for the assessment of UPS function and the development of genetic models to study the role of the UPS have led to the realization that often the function of this system deviates from the norm in many cardiovascular pathologies. Hence, dysfunction has been described in atherosclerosis, familial cardiac proteinopathies, idiopathic dilated cardiomyopathies, and myocardial ischemia. This has led to numerous studies of the ubiquitin protein (E3) ligases and their roles in cardiac physiology and pathophysiology. This has also led to the controversial proposition of treating atherosclerosis, cardiac hypertrophy, and myocardial ischemia with proteasome inhibitors. Furthering our knowledge of this system may help in the development of new UPS-based therapeutic modalities for mitigation of cardiovascular disease.
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Affiliation(s)
- Saul R Powell
- Center for Heart and Lung Research, The Feinstein Institute for Medical Research, Manhasset, New York, USA
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99
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Kojic S, Radojkovic D, Faulkner G. Muscle ankyrin repeat proteins: their role in striated muscle function in health and disease. Crit Rev Clin Lab Sci 2011; 48:269-94. [DOI: 10.3109/10408363.2011.643857] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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100
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Viganò A, Vasso M, Caretti A, Bravatà V, Terraneo L, Fania C, Capitanio D, Samaja M, Gelfi C. Protein modulation in mouse heart under acute and chronic hypoxia. Proteomics 2011; 11:4202-17. [PMID: 21948614 DOI: 10.1002/pmic.201000804] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 07/08/2011] [Accepted: 08/08/2011] [Indexed: 11/10/2022]
Abstract
Exploring cellular mechanisms underlying beneficial and detrimental responses to hypoxia represents the object of the present study. Signaling molecules controlling adaptation to hypoxia (HIF-1α), energy balance (AMPK), mitochondrial biogenesis (PGC-1α), autophagic/apoptotic processes regulation and proteomic dysregulation were assessed. Responses to acute hypoxia (AH) and chronic hypoxia (CH) in mouse heart proteome were detected by 2-D DIGE, mass spectrometry and antigen-antibody reactions. Both in AH and CH, the results indicated a deregulation of proteins related to sarcomere stabilization and muscle contraction. Neither in AH nor in CH the HIF-1α stabilization was observed. In AH, the metabolic adaptation to lack of oxygen was controlled by AMPK activation and sustained by an up-regulation of adenosylhomocysteinase and acetyl-CoA synthetase. AH was characterized by the mitophagic protein Bnip 3 increment. PGC-1α, a master regulator of mitochondrial biogenesis, was down-regulated. CH was characterized by the up-regulation of enzymes involved in antioxidant defense, in aldehyde bio-product detoxification and in misfolded protein degradation. In addition, a general down-regulation of enzymes controlling anaerobic metabolism was observed. After 10 days of hypoxia, cardioprotective molecules were substantially decreased whereas pro-apoptotic molecules increased accompained by down-regulation of specific target proteins.
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Affiliation(s)
- Agnese Viganò
- Dipartimento di Scienze e Tecnologie Biomediche, Università degli Studi di Milano, Segrate (MI), Italy
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