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Abstract
The giant protein titin forms a unique filament network in cardiomyocytes, which engages in both mechanical and signaling functions of the heart. TTN, which encodes titin, is also a major human disease gene. In this review, we cover the roles of cardiac titin in normal and failing hearts, with a special emphasis on the contribution of titin to diastolic stiffness. We provide an update on disease-associated titin mutations in cardiac and skeletal muscles and summarize what is known about the impact of protein-protein interactions on titin properties and functions. We discuss the importance of titin-isoform shifts and titin phosphorylation, as well as titin modifications related to oxidative stress, in adjusting the diastolic stiffness of the healthy and the failing heart. Along the way we distinguish among titin alterations in systolic and in diastolic heart failure and ponder the evidence for titin stiffness as a potential target for pharmacological intervention in heart disease.
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Affiliation(s)
- Wolfgang A Linke
- From the Department of Cardiovascular Physiology, Ruhr University Bochum, Bochum, Germany
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52
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Lamberts RR, Lingam SJ, Wang HY, Bollen IAE, Hughes G, Galvin IF, Bunton RW, Bahn A, Katare R, Baldi JC, Williams MJA, Saxena P, Coffey S, Jones PP. Impaired relaxation despite upregulated calcium-handling protein atrial myocardium from type 2 diabetic patients with preserved ejection fraction. Cardiovasc Diabetol 2014; 13:72. [PMID: 24708792 PMCID: PMC3997226 DOI: 10.1186/1475-2840-13-72] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/26/2014] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Diastolic dysfunction is a key factor in the development and pathology of cardiac dysfunction in diabetes, however the exact underlying mechanism remains unknown, especially in humans. We aimed to measure contraction, relaxation, expression of calcium-handling proteins and fibrosis in myocardium of diabetic patients with preserved systolic function. METHODS Right atrial appendages from patients with type 2 diabetes mellitus (DM, n = 20) and non-diabetic patients (non-DM, n = 36), all with preserved ejection fraction and undergoing coronary artery bypass grafting (CABG), were collected. From appendages, small cardiac muscles, trabeculae, were isolated to measure basal and β-adrenergic stimulated myocardial function. Expression levels of calcium-handling proteins, sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) and phospholamban (PLB), and of β1-adrenoreceptors were determined in tissue samples by Western blot. Collagen deposition was determined by picro-sirius red staining. RESULTS In trabeculae from diabetic samples, contractile function was preserved, but relaxation was prolonged (Tau: 74 ± 13 ms vs. 93 ± 16 ms, non-DM vs. DM, p = 0.03). The expression of SERCA2a was increased in diabetic myocardial tissue (0.75 ± 0.09 vs. 1.23 ± 0.15, non-DM vs. DM, p = 0.007), whereas its endogenous inhibitor PLB was reduced (2.21 ± 0.45 vs. 0.42 ± 0.11, non-DM vs. DM, p = 0.01). Collagen deposition was increased in diabetic samples. Moreover, trabeculae from diabetic patients were unresponsive to β-adrenergic stimulation, despite no change in β1-adrenoreceptor expression levels. CONCLUSIONS Human type 2 diabetic atrial myocardium showed increased fibrosis without systolic dysfunction but with impaired relaxation, especially during β-adrenergic challenge. Interestingly, changes in calcium-handling protein expression suggests accelerated active calcium re-uptake, thus improved relaxation, indicating a compensatory calcium-handling mechanism in diabetes in an attempt to maintain diastolic function at rest despite impaired relaxation in the diabetic fibrotic atrial myocardium. Our study addresses important aspects of the underlying mechanisms of diabetes-associated diastolic dysfunction, which is crucial to developing new therapeutic treatments.
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Affiliation(s)
- Regis R Lamberts
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Shivanjali J Lingam
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Heng-Yu Wang
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Ilse AE Bollen
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Gillian Hughes
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Ivor F Galvin
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Andrew Bahn
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Rajesh Katare
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - J Chris Baldi
- Department of Medicine – HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Michael JA Williams
- Department of Medicine – HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Pankaj Saxena
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine – HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Peter P Jones
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
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53
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Kaushik G, Engler AJ. From stem cells to cardiomyocytes: the role of forces in cardiac maturation, aging, and disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 126:219-42. [PMID: 25081620 DOI: 10.1016/b978-0-12-394624-9.00009-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Stem cell differentiation into a variety of lineages is known to involve signaling from the extracellular niche, including from the physical properties of that environment. What regulates stem cell responses to these cues is there ability to activate different mechanotransductive pathways. Here, we will review the structures and pathways that regulate stem cell commitment to a cardiomyocyte lineage, specifically examining proteins within muscle sarcomeres, costameres, and intercalated discs. Proteins within these structures stretch, inducing a change in their phosphorylated state or in their localization to initiate different signals. We will also put these changes in the context of stem cell differentiation into cardiomyocytes, their subsequent formation of the chambered heart, and explore negative signaling that occurs during disease.
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Affiliation(s)
- Gaurav Kaushik
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
| | - Adam J Engler
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
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Gritsyna YV, Salmov NN, Vikhlyantsev IM, Ulanova AD, Sharapov MG, Teplova VV, Podlubnaya ZA. Changes in gene expression and titin (connectin) content in striated muscles of chronically alcoholized rats. Mol Biol 2013. [DOI: 10.1134/s0026893313060058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Chung CS, Mitov MI, Callahan LA, Campbell KS. Increased myocardial short-range forces in a rodent model of diabetes reflect elevated content of β myosin heavy chain. Arch Biochem Biophys 2013; 552-553:92-9. [PMID: 24012810 DOI: 10.1016/j.abb.2013.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/02/2013] [Accepted: 08/24/2013] [Indexed: 01/13/2023]
Abstract
Diastolic dysfunction is a clinically significant problem for patients with diabetes and often reflects increased ventricular stiffness. Attached cross-bridges contribute to myocardial stiffness and produce short-range forces, but it is not yet known whether these forces are altered in diabetes. In this study, we tested the hypothesis that cross-bridge-based short-range forces are increased in the streptozotocin (STZ) induced rat model of type 1 diabetes. Chemically permeabilized myocardial preparations were obtained from 12week old rats that had been injected with STZ or vehicle 4weeks earlier, and activated in solutions with pCa (=-log10[Ca(2+)]) values ranging from 9.0 to 4.5. The short-range forces elicited by controlled length changes were ∼67% greater in the samples from the diabetic rats than in the control preparations. This change was mostly due to an increased elastic limit (the length change at the peak short-range force) as opposed to increased passive muscle stiffness. The STZ-induced increase in short-ranges forces is thus unlikely to reflect changes to titin and/or collagen filaments. Gel electrophoresis showed that STZ increased the relative expression of β myosin heavy chain. This molecular mechanism can explain the increased short-ranges forces observed in the diabetic tissue if β myosin molecules remain bound between the filaments for longer durations than α molecules during imposed movements. These results suggest that interventions that decrease myosin attachment times may be useful treatments for diastolic dysfunction associated with diabetes.
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Affiliation(s)
- Charles S Chung
- Department of Physiology, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, United States; Center for Muscle Biology, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, United States
| | - Mihail I Mitov
- Department of Physiology, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, United States; Center for Muscle Biology, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, United States
| | - Leigh Ann Callahan
- Center for Muscle Biology, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, United States; Division of Pulmonary, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, United States
| | - Kenneth S Campbell
- Department of Physiology, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, United States; Center for Muscle Biology, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, United States.
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56
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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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57
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Kötter S, Gout L, Von Frieling-Salewsky M, Müller AE, Helling S, Marcus K, Dos Remedios C, Linke WA, Krüger M. Differential changes in titin domain phosphorylation increase myofilament stiffness in failing human hearts. Cardiovasc Res 2013; 99:648-56. [PMID: 23764881 DOI: 10.1093/cvr/cvt144] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
AIMS Titin-based myofilament stiffness is defined by the expression levels of the cardiac titin-isoforms, N2B and N2BA, and by phosphorylation of the elastic titin domains N2-B unique sequence (N2-Bus) and PEVK. Phosphorylation of the N2-Bus by cGMP-dependent protein kinase (PKG) or cAMP-dependent protein kinase (PKA) decreases titin stiffness, whereas phosphorylation of the PEVK-domain by PKC increases it. We aimed to identify specific sites within the N2-Bus phosphorylated by PKA and PKG and to determine whether differential changes in titin domain phosphorylation could affect passive stiffness in human failing hearts. METHODS AND RESULTS Using mass spectrometry, we identified seven partly conserved PKA/PKG-targeted phosphorylation motifs in human and rat N2-Bus. Polyclonal antibodies to pSer4185, pSer4010, and pSer4099 in the N2-Bus, and to pSer11878 in the PEVK-region were used to quantify titin-domain phosphorylation by western blot analyses of a set of human donor and failing hearts with similar titin-isoform composition. Passive tension determined in skinned human myocardial fibre preparations was significantly increased in failing compared with donor hearts, notably at shorter sarcomere lengths where titin contributes most to total passive tension. Phosphorylation of Ser4185, Ser4010, and Ser4099 in the N2-Bus was significantly reduced in failing hearts, whereas phosphorylation of Ser11878 in the PEVK-region was increased compared with donor hearts. CONCLUSION We conclude that hypo-phosphorylation of the N2-Bus and hyper-phosphorylation of the PEVK domain can act complementary to elevate passive tension in failing human hearts. Differential changes in titin-domain phosphorylation may be important to fine-tune passive myocardial stiffness and diastolic function of the heart.
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Affiliation(s)
- Sebastian Kötter
- Department of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Germany
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58
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van Heerebeek L, Franssen CPM, Hamdani N, Verheugt FWA, Somsen GA, Paulus WJ. Molecular and cellular basis for diastolic dysfunction. Curr Heart Fail Rep 2013; 9:293-302. [PMID: 22926993 DOI: 10.1007/s11897-012-0109-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Heart failure with preserved ejection fraction (HFpEF) is highly prevalent and is frequently associated with metabolic risk factors. Patients with HFpEF have only a slightly lower mortality than patients with HF and reduced EF. The pathophysiology of HFpEF is currently incompletely understood, which precludes specific therapy. Both HF phenotypes demonstrate distinct cardiac remodeling processes at the macroscopic, microscopic, and ultrastructural levels. Increased diastolic left-ventricular (LV) stiffness and impaired LV relaxation are important features of HFpEF, which can be explained by changes in the extracellular matrix and the cardiomyocytes. In HFpEF, elevated intrinsic cardiomyocyte stiffness contributes to high diastolic LV stiffness. Posttranslational changes in the sarcomeric protein titin, affecting titin isoform expression and phosphorylation, contribute to elevated cardiomyocyte stiffness. Increased nitrosative/oxidative stress, impaired nitric oxide bioavailability, and down-regulation of myocardial cyclic guanosine monophosphate and protein kinase G signaling could trigger posttranslational modifications of titin, thereby augmenting cardiomyocyte and LV diastolic stiffness.
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Affiliation(s)
- Loek van Heerebeek
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
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Dowling D, McAuliffe FM. The molecular mechanisms of offspring effects from obese pregnancy. Obes Facts 2013; 6:134-45. [PMID: 23571656 PMCID: PMC5644678 DOI: 10.1159/000350706] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 06/29/2012] [Indexed: 11/19/2022] Open
Abstract
The incidence of obesity, increased weight gain and the popularity of high-fat / high-sugar diets are seriously impacting upon the global population. Billions of individuals are affected, and although diet and lifestyle are of paramount importance to the development of adult obesity, compelling evidence is emerging which suggests that maternal obesity and related disorders may be passed on to the next generation by non-genetic means. The processes acting within the uteri of obese mothers may permanently predispose offspring to a diverse plethora of diseases ranging from obesity and diabetes to psychiatric disorders. This review aims to summarise some of the molecular mechanisms and active processes currently known about maternal obesity and its effect on foetal and neonatal physiology and metabolism. Complex and multifactorial networks of molecules are intertwined and culminate in a pathologically synergistic manner to cause disruption and disorganisation of foetal physiology. This altered phenotype may potentiate the cycle of intergenerational transmission of obesity and related disorders.
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Affiliation(s)
| | - Fionnuala M. McAuliffe
- *Prof. Dr. Fionnuala M. McAuliffe, UCD Obstetrics & Gynaecology, School of Medicine and Medical Science, University College Dublin, National Maternity Hospital, Dublin 2 (Ireland),
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60
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Kähne T, Kolodziej A, Smalla KH, Eisenschmidt E, Haus UU, Weismantel R, Kropf S, Wetzel W, Ohl FW, Tischmeyer W, Naumann M, Gundelfinger ED. Synaptic proteome changes in mouse brain regions upon auditory discrimination learning. Proteomics 2012; 12:2433-44. [PMID: 22696468 PMCID: PMC3509369 DOI: 10.1002/pmic.201100669] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Changes in synaptic efficacy underlying learning and memory processes are assumed to be associated with alterations of the protein composition of synapses. Here, we performed a quantitative proteomic screen to monitor changes in the synaptic proteome of four brain areas (auditory cortex, frontal cortex, hippocampus striatum) during auditory learning. Mice were trained in a shuttle box GO/NO-GO paradigm to discriminate between rising and falling frequency modulated tones to avoid mild electric foot shock. Control-treated mice received corresponding numbers of either the tones or the foot shocks. Six hours and 24 h later, the composition of a fraction enriched in synaptic cytomatrix-associated proteins was compared to that obtained from naïve mice by quantitative mass spectrometry. In the synaptic protein fraction obtained from trained mice, the average percentage (±SEM) of downregulated proteins (59.9 ± 0.5%) exceeded that of upregulated proteins (23.5 ± 0.8%) in the brain regions studied. This effect was significantly smaller in foot shock (42.7 ± 0.6% down, 40.7 ± 1.0% up) and tone controls (43.9 ± 1.0% down, 39.7 ± 0.9% up). These data suggest that learning processes initially induce removal and/or degradation of proteins from presynaptic and postsynaptic cytoskeletal matrices before these structures can acquire a new, postlearning organisation. In silico analysis points to a general role of insulin-like signalling in this process.
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Affiliation(s)
- Thilo Kähne
- Institute of Experimental Internal Medicine, Medical School, Otto von Guericke University, Magdeburg, Germany
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61
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RBM20, a gene for hereditary cardiomyopathy, regulates titin splicing. Nat Med 2012; 18:766-73. [PMID: 22466703 DOI: 10.1038/nm.2693] [Citation(s) in RCA: 398] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 01/31/2012] [Indexed: 01/15/2023]
Abstract
Alternative splicing has a major role in cardiac adaptive responses, as exemplified by the isoform switch of the sarcomeric protein titin, which adjusts ventricular filling. By positional cloning using a previously characterized rat strain with altered titin mRNA splicing, we identified a loss-of-function mutation in the gene encoding RNA binding motif protein 20 (Rbm20) as the underlying cause of pathological titin isoform expression. The phenotype of Rbm20-deficient rats resembled the pathology seen in individuals with dilated cardiomyopathy caused by RBM20 mutations. Deep sequencing of the human and rat cardiac transcriptome revealed an RBM20-dependent regulation of alternative splicing. In addition to titin (TTN), we identified a set of 30 genes with conserved splicing regulation between humans and rats. This network is enriched for genes that have previously been linked to cardiomyopathy, ion homeostasis and sarcomere biology. Our studies emphasize the key role of post-transcriptional regulation in cardiac function and provide mechanistic insights into the pathogenesis of human heart failure.
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62
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van der Velden J, Merkus D, de Beer V, Hamdani N, Linke WA, Boontje NM, Stienen GJM, Duncker DJ. Transmural heterogeneity of myofilament function and sarcomeric protein phosphorylation in remodeled myocardium of pigs with a recent myocardial infarction. Front Physiol 2011; 2:83. [PMID: 22131977 PMCID: PMC3223384 DOI: 10.3389/fphys.2011.00083] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 10/28/2011] [Indexed: 02/05/2023] Open
Abstract
Aim: Transmural differences in sarcomeric protein composition and function across the left ventricular (LV) wall have been reported. We studied in pigs sarcomeric function and protein phosphorylation in subepicardial (EPI) and subendocardial (ENDO) layers of remote LV myocardium after myocardial infarction (MI), induced by left circumflex coronary artery ligation. Methods: EPI and ENDO samples were taken 3 weeks after sham surgery (n = 12) or induction of MI (n = 12) at baseline (BL) and during β-adrenergic receptor (βAR) stimulation with dobutamine. Isometric force was measured in single cardiomyocytes at various [Ca2+] and 2.2 μm sarcomere length. Results: In sham hearts, no significant transmural differences were observed in myofilament function or protein phosphorylation. Myofilament Ca2+-sensitivity was significantly higher in both EPI and ENDO of MI compared to sham hearts. Maximal force was significantly reduced in MI compared to sham, but solely in ENDO cells. A higher passive force was observed in MI hearts, but only in EPI cells. The proportion of stiff N2B isoform was higher in EPI than in ENDO in both sham and MI hearts, and a trend toward increased N2B-proportion appeared in MI EPI, but not MI Endo. Analysis of myofilament protein phosphorylation did not reveal significant transmural differences in phosphorylation of myosin binding protein C, desmin, troponin T, troponin I (cTnI), and myosin light chain 2 (MLC-2) both at BL and during βAR stimulation with dobutamine infusion. A significant increase in MLC-2 phosphorylation was observed during dobutamine only in sham. In addition, the increase in cTnI phosphorylation upon dobutamine was twofold lower in MI than in sham. Conclusion: Myofilament dysfunction is present in both EPI and ENDO in post-MI remodeled myocardium, but shows a high degree of qualitative heterogeneity across the LV wall. These heterogeneous transmural changes in sarcomeric properties likely contribute differently to systolic vs. diastolic global LV dysfunction after MI.
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Affiliation(s)
- Jolanda van der Velden
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Netherlands
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63
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Falcão-Pires I, Hamdani N, Borbély A, Gavina C, Schalkwijk CG, van der Velden J, van Heerebeek L, Stienen GJ, Niessen HW, Leite-Moreira AF, Paulus WJ. Diabetes Mellitus Worsens Diastolic Left Ventricular Dysfunction in Aortic Stenosis Through Altered Myocardial Structure and Cardiomyocyte Stiffness. Circulation 2011; 124:1151-9. [DOI: 10.1161/circulationaha.111.025270] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Inês Falcão-Pires
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Nazha Hamdani
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Attila Borbély
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Cristina Gavina
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Casper G. Schalkwijk
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Jolanda van der Velden
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Loek van Heerebeek
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Ger J.M. Stienen
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Hans W.M. Niessen
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Adelino F. Leite-Moreira
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
| | - Walter J. Paulus
- From the Departments of Physiology (I.F.-P., N.H., A.B., J.v.d.V., L.v.H., G.J.M.S., W.J.P.) and Pathology and Cardiac Surgery (H.W.M.N.), Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, the Netherlands; Departments of Physiology and Cardiothoracic Surgery (I.F.-P., A.F.L.-M.) and Cardiology (C.G.), Faculty of Medicine, Universidade do Porto, and Center of Thoracic Surgery (A.F.L.-M.), Hospital de São João, Porto, Portugal; Department of Internal Medicine,
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Roe ND, Thomas DP, Ren J. Inhibition of NADPH oxidase alleviates experimental diabetes-induced myocardial contractile dysfunction. Diabetes Obes Metab 2011; 13:465-73. [PMID: 21272185 DOI: 10.1111/j.1463-1326.2011.01369.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
AIM O(2) (-) production is implicated in cardiac dysfunction for a number of diseases including diabetes. Activation of the O(2) (-)-producing enzyme NADPH oxidase is seen in diabetes, although its role in diabetic cardiomyopathy is unclear. This study was designed to evaluate the effect of NADPH oxidase inhibition on cardiac function in diabetes. METHODS Experimental diabetes was induced in adult C57 mice using streptozotocin (STZ, 150 mg/kg, i.p.) prior to the administration of the NADPH oxidase inhibitor apocynin (4 mg/kg/day) for 2 weeks. Left ventricular (LV) and myocyte contractile functions were evaluated using echocardiography and edge-detection, respectively. RESULTS STZ elicited hyperglycaemia and reduced body weight gain, which was unaffected by apocynin. STZ significantly reduced fractional shortening, LV wall thickness, peak shortening, maximal velocity and duration of shortening or relengthening, the effects of which - with the exception of wall thickness - were significantly attenuated or ablated by apocynin. Western blot analysis revealed that the effects of comparable Akt phosphorylation, reduced AMPK phosphorylation, downregulation of sarco(endo)plasmic reticulum Ca(2+)-ATPase and lessened phosphorylation of phospholamban in diabetic myocardium were unaffected by apocynin. Both apocynin and the nitric oxide synthase (NOS) inhibitor l-arginine methyl ester (L-NAME) inhibited elevated O(2) (-) production in diabetes without any additive effect between the two, indicating the presence of endothelial nitric oxide synthase (eNOS) uncoupling. However, neither diabetes nor apocynin altered the expression of heat shock protein 90 and eNOS phosphorylation (Ser(1177)). In addition, apocynin mitigated elevated levels of nitrotyrosine and nitric oxide in diabetes. CONCLUSION Taken together, these data indicate the beneficial role of NADPH oxidase inhibition in diabetes-induced myocardial contractile dysfunction.
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Affiliation(s)
- N D Roe
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, USA
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Linke WA, Krüger M. The Giant Protein Titin as an Integrator of Myocyte Signaling Pathways. Physiology (Bethesda) 2010; 25:186-98. [DOI: 10.1152/physiol.00005.2010] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The giant muscle protein titin, the “backbone” of the sarcomere, harbors a complex molecular spring whose stiffness is variably tuned in health and disease. Titin is increasingly recognized as a crucial integrator of diverse myocyte signaling pathways. The titin-associated signalosome includes hotspots of protein-protein interactions important for the regulation of protein quality-control mechanisms, hypertrophic gene activation, and mechanosensing.
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Affiliation(s)
- Wolfgang A. Linke
- Department of Cardiovascular Physiology, Institute of Physiology, Ruhr University Bochum, Bochum, Germany
| | - Martina Krüger
- Department of Cardiovascular Physiology, Institute of Physiology, Ruhr University Bochum, Bochum, Germany
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