1
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Martin TG, Pak H, Gerhard GS, Merali S, Merali C, Lemster B, Dubey P, McTiernan CF, Bristow MR, Feldman AM, Kirk JA. Dysregulated Autophagy and Sarcomere Dysfunction in Patients With Heart Failure With Co-Occurrence of P63A and P380S BAG3 Variants. J Am Heart Assoc 2023; 12:e029938. [PMID: 38108245 PMCID: PMC10863766 DOI: 10.1161/jaha.123.029938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
BACKGROUND Mutations to the co-chaperone protein BAG3 (B-cell lymphoma-2-associated athanogene-3) are a leading cause of dilated cardiomyopathy (DCM). These mutations often impact the C-terminal BAG domain (residues 420-499), which regulates heat shock protein 70-dependent protein turnover via autophagy. While mutations in other regions are less common, previous studies in patients with DCM found that co-occurrence of 2 BAG3 variants (P63A, P380S) led to worse prognosis. However, the underlying mechanism for dysfunction is not fully understood. METHODS AND RESULTS In this study, we used proteomics, Western blots, and myofilament functional assays on left ventricular tissue from patients with nonfailing, DCM, and DCM with BAG363/380 to determine how these mutations impact protein quality control and cardiomyocyte contractile function. We found dysregulated autophagy and increased protein ubiquitination in patients with BAG363/380 compared with nonfailing and DCM, suggesting impaired protein turnover. Expression and myofilament localization of BAG3-binding proteins were also uniquely altered in the BAG3,63/380 including abolished localization of the small heat shock protein CRYAB (alpha-crystallin B chain) to the sarcomere. To determine whether these variants impacted sarcomere function, we used cardiomyocyte force-calcium assays and found reduced maximal calcium-activated force in DCM and BAG363/380. Interestingly, myofilament calcium sensitivity was increased in DCM but not with BAG363/380, which was not explained by differences in troponin I phosphorylation. CONCLUSIONS Together, our data support that the disease-enhancing mechanism for BAG3 variants outside of the BAG domain is through disrupted protein turnover leading to compromised sarcomere function. These findings suggest a shared mechanism of disease among pathogenic BAG3 variants, regardless of location.
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Affiliation(s)
- Thomas G. Martin
- Department of Cell and Molecular PhysiologyLoyola University Chicago Stritch School of MedicineMaywoodIL
| | - Hana Pak
- Department of Cell and Molecular PhysiologyLoyola University Chicago Stritch School of MedicineMaywoodIL
| | - Glenn S. Gerhard
- Department of Medical Genetics and Molecular BiochemistryLewis Katz School of Medicine of Temple UniversityPhiladelphiaPA
| | - Salim Merali
- Temple University School of PharmacyPhiladelphiaPA
| | | | - Bonnie Lemster
- The Heart and Vascular Institute, The University of Pittsburgh School of MedicinePittsburghPA
| | - Praveen Dubey
- Department of Biomedical EngineeringUniversity of Alabama at BirminghamBirminghamAL
| | - Charles F. McTiernan
- The Heart and Vascular Institute, The University of Pittsburgh School of MedicinePittsburghPA
| | | | - Arthur M. Feldman
- Department of Medicine, Division of CardiologyThe Lewis Katz School of Medicine at Temple UniversityPhiladelphiaPA
| | - Jonathan A. Kirk
- Department of Cell and Molecular PhysiologyLoyola University Chicago Stritch School of MedicineMaywoodIL
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2
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Szedlak P, Steele D, Hopkins P. Cardiac muscle physiology. BJA Educ 2023; 23:350-357. [PMID: 37600215 PMCID: PMC10435365 DOI: 10.1016/j.bjae.2023.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2023] [Indexed: 08/22/2023] Open
Affiliation(s)
- P. Szedlak
- Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | | | - P.M. Hopkins
- Leeds Teaching Hospitals NHS Trust, Leeds, UK
- University of Leeds, Leeds, UK
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3
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Hanft LM, Robinett JC, Kalogeris TJ, Campbell KS, Biesiadecki BJ, McDonald KS. Thin filament regulation of cardiac muscle power output: Implications for targets to improve human failing hearts. J Gen Physiol 2023; 155:e202213290. [PMID: 37000170 PMCID: PMC10067705 DOI: 10.1085/jgp.202213290] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/14/2023] [Accepted: 03/13/2023] [Indexed: 04/01/2023] Open
Abstract
The heart's pumping capacity is determined by myofilament power generation. Power is work done per unit time and measured as the product of force and velocity. At a sarcomere level, these contractile properties are linked to the number of attached cross-bridges and their cycling rate, and many signaling pathways modulate one or both factors. We previously showed that power is increased in rodent permeabilized cardiac myocytes following PKA-mediated phosphorylation of myofibrillar proteins. The current study found that that PKA increased power by ∼30% in permeabilized cardiac myocyte preparations (n = 8) from human failing hearts. To address myofilament molecular specificity of PKA effects, mechanical properties were measured in rat permeabilized slow-twitch skeletal muscle fibers before and after exchange of endogenous slow skeletal troponin with recombinant human Tn complex that contains cardiac (c)TnT, cTnC and either wildtype (WT) cTnI or pseudo-phosphorylated cTnI at sites Ser23/24Asp, Tyr26Glu, or the combinatorial Ser23/24Asp and Tyr26Glu. We found that cTnI Ser23/24Asp, Tyr26Glu, and combinatorial Ser23/24Asp and Tyr26Glu were sufficient to increase power by ∼20%. Next, we determined whether pseudo-phosphorylated cTnI at Ser23/24 was sufficient to increase power in cardiac myocytes from human failing hearts. Following cTn exchange that included cTnI Ser23/24Asp, power output increased ∼20% in permeabilized cardiac myocyte preparations (n = 6) from the left ventricle of human failing hearts. These results implicate cTnI N-terminal phosphorylation as a molecular regulator of myocyte power and could serve as a regional target for small molecule therapy to unmask myocyte power reserve capacity in human failing hearts.
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Affiliation(s)
- Laurin M. Hanft
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Joel C. Robinett
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Theodore J. Kalogeris
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Kenneth S. Campbell
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, USA
| | | | - Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA
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4
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Sevrieva IR, Ponnam S, Yan Z, Irving M, Kampourakis T, Sun YB. Phosphorylation-dependent interactions of myosin-binding protein C and troponin coordinate the myofilament response to protein kinase A. J Biol Chem 2023; 299:102767. [PMID: 36470422 PMCID: PMC9826837 DOI: 10.1016/j.jbc.2022.102767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022] Open
Abstract
PKA-mediated phosphorylation of sarcomeric proteins enhances heart muscle performance in response to β-adrenergic stimulation and is associated with accelerated relaxation and increased cardiac output for a given preload. At the cellular level, the latter translates to a greater dependence of Ca2+ sensitivity and maximum force on sarcomere length (SL), that is, enhanced length-dependent activation. However, the mechanisms by which PKA phosphorylation of the most notable sarcomeric PKA targets, troponin I (cTnI) and myosin-binding protein C (cMyBP-C), lead to these effects remain elusive. Here, we specifically altered the phosphorylation level of cTnI in heart muscle cells and characterized the structural and functional effects at different levels of background phosphorylation of cMyBP-C and with two different SLs. We found Ser22/23 bisphosphorylation of cTnI was indispensable for the enhancement of length-dependent activation by PKA, as was cMyBP-C phosphorylation. This high level of coordination between cTnI and cMyBP-C may suggest coupling between their regulatory mechanisms. Further evidence for this was provided by our finding that cardiac troponin (cTn) can directly interact with cMyBP-C in vitro, in a phosphorylation- and Ca2+-dependent manner. In addition, bisphosphorylation at Ser22/Ser23 increased Ca2+ sensitivity at long SL in the presence of endogenously phosphorylated cMyBP-C. When cMyBP-C was dephosphorylated, bisphosphorylation of cTnI increased Ca2+ sensitivity and decreased cooperativity at both SLs, which may translate to deleterious effects in physiological settings. Our results could have clinical relevance for disease pathways, where PKA phosphorylation of cTnI may be functionally uncoupled from cMyBP-C phosphorylation due to mutations or haploinsufficiency.
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Affiliation(s)
- Ivanka R Sevrieva
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom.
| | - Saraswathi Ponnam
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Ziqian Yan
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Malcolm Irving
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Thomas Kampourakis
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Yin-Biao Sun
- Randall Centre for Cell and Molecular Biophysics, and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
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5
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Numata G, Takimoto E. Cyclic GMP and PKG Signaling in Heart Failure. Front Pharmacol 2022; 13:792798. [PMID: 35479330 PMCID: PMC9036358 DOI: 10.3389/fphar.2022.792798] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Cyclic guanosine monophosphate (cGMP), produced by guanylate cyclase (GC), activates protein kinase G (PKG) and regulates cardiac remodeling. cGMP/PKG signal is activated by two intrinsic pathways: nitric oxide (NO)-soluble GC and natriuretic peptide (NP)-particulate GC (pGC) pathways. Activation of these pathways has emerged as a potent therapeutic strategy to treat patients with heart failure, given cGMP-PKG signaling is impaired in heart failure with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). Large scale clinical trials in patients with HFrEF have shown positive results with agents that activate cGMP-PKG pathways. In patients with HFpEF, however, benefits were observed only in a subgroup of patients. Further investigation for cGMP-PKG pathway is needed to develop better targeting strategies for HFpEF. This review outlines cGMP-PKG pathway and its modulation in heart failure.
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Affiliation(s)
- Genri Numata
- Department of Cardiovascular Medicine, The University of Tokyo Hospital, Tokyo, Japan
- Department of Advanced Translational Research and Medicine in Management of Pulmonary Hypertension, The University of Tokyo Hospital, Tokyo, Japan
| | - Eiki Takimoto
- Department of Cardiovascular Medicine, The University of Tokyo Hospital, Tokyo, Japan
- Division of Cardiology, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, MD, United States
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6
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Landim-Vieira M, Childers MC, Wacker AL, Garcia MR, He H, Singh R, Brundage EA, Johnston JR, Whitson BA, Chase PB, Janssen PML, Regnier M, Biesiadecki BJ, Pinto JR, Parvatiyar MS. Post-translational modification patterns on β-myosin heavy chain are altered in ischemic and nonischemic human hearts. eLife 2022; 11:74919. [PMID: 35502901 PMCID: PMC9122498 DOI: 10.7554/elife.74919] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 05/01/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphorylation and acetylation of sarcomeric proteins are important for fine-tuning myocardial contractility. Here, we used bottom-up proteomics and label-free quantification to identify novel post-translational modifications (PTMs) on β-myosin heavy chain (β-MHC) in normal and failing human heart tissues. We report six acetylated lysines and two phosphorylated residues: K34-Ac, K58-Ac, S210-P, K213-Ac, T215-P, K429-Ac, K951-Ac, and K1195-Ac. K951-Ac was significantly reduced in both ischemic and nonischemic failing hearts compared to nondiseased hearts. Molecular dynamics (MD) simulations show that K951-Ac may impact stability of thick filament tail interactions and ultimately myosin head positioning. K58-Ac altered the solvent-exposed SH3 domain surface - known for protein-protein interactions - but did not appreciably change motor domain conformation or dynamics under conditions studied. Together, K213-Ac/T215-P altered loop 1's structure and dynamics - known to regulate ADP-release, ATPase activity, and sliding velocity. Our study suggests that β-MHC acetylation levels may be influenced more by the PTM location than the type of heart disease since less protected acetylation sites are reduced in both heart failure groups. Additionally, these PTMs have potential to modulate interactions between β-MHC and other regulatory sarcomeric proteins, ADP-release rate of myosin, flexibility of the S2 region, and cardiac myofilament contractility in normal and failing hearts.
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Affiliation(s)
- Maicon Landim-Vieira
- Department of Biomedical Sciences, College of Medicine, The Florida State UniversityTallahasseeUnited States
| | - Matthew C Childers
- Department of Bioengineering, College of Medicine, University of WashingtonSeattleUnited States
| | - Amanda L Wacker
- Department of Nutrition and Integrative Physiology, The Florida State UniversityTallahasseeUnited States
| | - Michelle Rodriquez Garcia
- Department of Biomedical Sciences, College of Medicine, The Florida State UniversityTallahasseeUnited States
| | - Huan He
- Department of Biomedical Sciences, College of Medicine, The Florida State UniversityTallahasseeUnited States,Translational Science Laboratory, College of Medicine, The Florida State UniversityTallahasseeUnited States
| | - Rakesh Singh
- Department of Biomedical Sciences, College of Medicine, The Florida State UniversityTallahasseeUnited States,Translational Science Laboratory, College of Medicine, The Florida State UniversityTallahasseeUnited States
| | - Elizabeth A Brundage
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State UniversityColumbusUnited States
| | - Jamie R Johnston
- Department of Biomedical Sciences, College of Medicine, The Florida State UniversityTallahasseeUnited States
| | - Bryan A Whitson
- Department of Surgery, College of Medicine, The Ohio State UniversityColumbusUnited States
| | - P Bryant Chase
- Department of Biological Science, The Florida State UniversityTallahasseeUnited States
| | - Paul ML Janssen
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State UniversityColumbusUnited States
| | - Michael Regnier
- Department of Bioengineering, College of Medicine, University of WashingtonSeattleUnited States
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State UniversityColumbusUnited States
| | - J Renato Pinto
- Department of Biomedical Sciences, College of Medicine, The Florida State UniversityTallahasseeUnited States
| | - Michelle S Parvatiyar
- Department of Nutrition and Integrative Physiology, The Florida State UniversityTallahasseeUnited States
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7
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Yoon S, Gergs U, McMullen JR, Eom GH. Overexpression of Heat Shock Protein 70 Improves Cardiac Remodeling and Survival in Protein Phosphatase 2A-Expressing Transgenic Mice with Chronic Heart Failure. Cells 2021; 10:cells10113180. [PMID: 34831402 PMCID: PMC8624068 DOI: 10.3390/cells10113180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/05/2021] [Accepted: 11/12/2021] [Indexed: 12/28/2022] Open
Abstract
Heat shock protein (HSP) 70 is a molecular chaperone that regulates protein structure in response to thermal stress. In addition, HSP70 is involved in post-translational modification and is related to the severity of some diseases. Here, we tested the functional relevance of long-lasting HSP70 expression in a model of nonischemic heart failure using protein phosphatase 2 catalytic subunit A (PP2CA)-expressing transgenic mice. These transgenic mice, with cardiac-specific overexpression of PP2CA, abruptly died after 12 weeks of postnatal life. Serial echocardiograms to assess cardiac function revealed that the ejection fraction (EF) was gradually decreased in transgenic PP2CA (TgPP2CA) mice. In addition, PP2CA expression exacerbated systolic dysfunction and LV dilatation, with free wall thinning, which are indicators of fatal dilated cardiomyopathy. Interestingly, simultaneous expression of HSP70 in double transgenic mice (dTg) significantly improved the dilated cardiomyopathy phenotype of TgPP2CA mice. We observed better survival, preserved EF, reduced chamber enlargement, and suppression of free wall thinning. In the proposed molecular mechanism, HSP70 preferentially regulates the phosphorylation of AKT. Phosphorylation of AKT was significantly reduced in TgPP2CA mice but was not significantly lower in dTg mice. Signal crosstalk between AKT and its substrates, in association with HSP70, might be a useful intervention for patients with nonischemic heart failure to suppress cardiac remodeling and improve survival.
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Affiliation(s)
- Somy Yoon
- Department of Pharmacology, Chonnam National University Medical School, Hwasun 58128, Korea
- Correspondence: (S.Y.); (G.H.E.); Tel.: +82-61-379-2843 (S.Y.); +82-61-379-2837 (G.H.E.)
| | - Ulrich Gergs
- Institute of Pharmacology and Toxicology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany;
| | | | - Gwang Hyeon Eom
- Department of Pharmacology, Chonnam National University Medical School, Hwasun 58128, Korea
- Correspondence: (S.Y.); (G.H.E.); Tel.: +82-61-379-2843 (S.Y.); +82-61-379-2837 (G.H.E.)
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8
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Martin TG, Myers VD, Dubey P, Dubey S, Perez E, Moravec CS, Willis MS, Feldman AM, Kirk JA. Cardiomyocyte contractile impairment in heart failure results from reduced BAG3-mediated sarcomeric protein turnover. Nat Commun 2021; 12:2942. [PMID: 34011988 PMCID: PMC8134551 DOI: 10.1038/s41467-021-23272-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 04/22/2021] [Indexed: 12/22/2022] Open
Abstract
The association between reduced myofilament force-generating capacity (Fmax) and heart failure (HF) is clear, however the underlying molecular mechanisms are poorly understood. Here, we show impaired Fmax arises from reduced BAG3-mediated sarcomere turnover. Myofilament BAG3 expression decreases in human HF and positively correlates with Fmax. We confirm this relationship using BAG3 haploinsufficient mice, which display reduced Fmax and increased myofilament ubiquitination, suggesting impaired protein turnover. We show cardiac BAG3 operates via chaperone-assisted selective autophagy (CASA), conserved from skeletal muscle, and confirm sarcomeric CASA complex localization is BAG3/proteotoxic stress-dependent. Using mass spectrometry, we characterize the myofilament CASA interactome in the human heart and identify eight clients of BAG3-mediated turnover. To determine if increasing BAG3 expression in HF can restore sarcomere proteostasis/Fmax, HF mice were treated with rAAV9-BAG3. Gene therapy fully rescued Fmax and CASA protein turnover after four weeks. Our findings indicate BAG3-mediated sarcomere turnover is fundamental for myofilament functional maintenance. Decreased expression of BAG3 in the heart is associated with contractile dysfunction and heart failure. Here the authors show that this is due to decreased BAG3-dependent sarcomere protein turnover, which impairs mechanical function, and that sarcomere force-generating capacity is restored with BAG3 gene therapy.
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Affiliation(s)
- Thomas G Martin
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL, USA
| | - Valerie D Myers
- Department of Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Praveen Dubey
- Department of Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Shubham Dubey
- Department of Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Edith Perez
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL, USA
| | - Christine S Moravec
- Department of Medicine, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA
| | - Monte S Willis
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Arthur M Feldman
- Department of Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL, USA.
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9
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Corbett JR, Robinson DE, Patrie SM. Robustness and Ruggedness of Isoelectric Focusing and Superficially Porous Liquid Chromatography with Fourier Transform Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:346-354. [PMID: 33274937 PMCID: PMC10476448 DOI: 10.1021/jasms.0c00355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
An investigation of a multidimensional proteomics workflow composed of off-gel isoelectric focusing (IEF) and superficially porous liquid chromatography (SPLC) with Fourier transform mass spectrometry (FTMS) was completed in order to assess various figures of merit associated with intact protein measurements. Triplicate analysis performed at both high and low FTMS resolutions on the E. coli proteome resulted in ∼900 redundant proteoforms from 3 to 95 kDa. Normalization of the chromatographic axis to identified proteoforms enabled reproducible physicochemical property measurements between proteome replicates with inter-replicate variances of ±3 ppm mass error for proteoforms <30 kDa, ±1.1 Da for proteins >30 kDa, ±12 s retention time error, and ±0.21 pI units. The results for E. coli and standard proteins revealed a correlation between pI precision and proteoform abundance with species detected in multiple IEF fractions exhibiting pI precisions less than the theoretical resolution of the off-gel system (±0.05 vs ±0.17, respectively). Evaluation of differentially modified proteoforms of standard proteins revealed that high sample loads (100s μgrams) change the IEF pH gradient profile, leading to sample broadening that facilitates resolution of charged post-translational modifications (e.g., phosphorylation, sialylation). Despite the impact of sample load on IEF resolution, results on standard proteins measured directly or after being spiked into E. coli demonstrated that the reproducibility of the workflow permitted recombination of the MS signal across IEF fractions in a manner supporting the evaluation of three label-free quantitation metrics for intact protein studies (proteoforms, proteoform ratios, and protein) over 102-103 sample amount with low femtomole detection limits.
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Affiliation(s)
- John R Corbett
- Department of Pathology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
- Department of Bioengineering, UT Dallas, 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Dana E Robinson
- Department of Pathology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | - Steven M Patrie
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Pathology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
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10
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Vikhorev PG, Vikhoreva NN, Yeung W, Li A, Lal S, dos Remedios CG, Blair CA, Guglin M, Campbell KS, Yacoub MH, de Tombe P, Marston SB. Titin-truncating mutations associated with dilated cardiomyopathy alter length-dependent activation and its modulation via phosphorylation. Cardiovasc Res 2020; 118:241-253. [PMID: 33135063 PMCID: PMC8752363 DOI: 10.1093/cvr/cvaa316] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 10/20/2020] [Indexed: 12/18/2022] Open
Abstract
Abstract
Aims
Dilated cardiomyopathy (DCM) is associated with mutations in many genes encoding sarcomere proteins. Truncating mutations in the titin gene TTN are the most frequent. Proteomic and functional characterizations are required to elucidate the origin of the disease and the pathogenic mechanisms of TTN-truncating variants.
Methods and results
We isolated myofibrils from DCM hearts carrying truncating TTN mutations and measured the Ca2+ sensitivity of force and its length dependence. Simultaneous measurement of force and adenosine triphosphate (ATP) consumption in skinned cardiomyocytes was also performed. Phosphorylation levels of troponin I (TnI) and myosin binding protein-C (MyBP-C) were manipulated using protein kinase A and λ phosphatase. mRNA sequencing was employed to overview gene expression profiles. We found that Ca2+ sensitivity of myofibrils carrying TTN mutations was significantly higher than in myofibrils from donor hearts. The length dependence of the Ca2+ sensitivity was absent in DCM myofibrils with TTN-truncating variants. No significant difference was found in the expression level of TTN mRNA between the DCM and donor groups. TTN exon usage and splicing were also similar. However, we identified down-regulation of genes encoding Z-disk proteins, while the atrial-specific regulatory myosin light chain gene, MYL7, was up-regulated in DCM patients with TTN-truncating variants.
Conclusion
Titin-truncating mutations lead to decreased length-dependent activation and increased elasticity of myofibrils. Phosphorylation levels of TnI and MyBP-C seen in the left ventricles are essential for the length-dependent changes in Ca2+ sensitivity in healthy donors, but they are reduced in DCM patients with TTN-truncating variants. A decrease in expression of Z-disk proteins may explain the observed decrease in myofibril passive stiffness and length-dependent activation.
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Affiliation(s)
- Petr G Vikhorev
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Natalia N Vikhoreva
- Heart Science Centre, Magdi Yacoub Institute, Harefield Hospital, London UB9 6JH, UK
| | - WaiChun Yeung
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Amy Li
- Department of Pharmacy and Biomedical Sciences, La Trobe University, Bendigo, VIC 3550, Australia
| | - Sean Lal
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW 2006, Australia
| | - Cristobal G dos Remedios
- Division of Molecular Cardiology and Biophysics, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - Cheavar A Blair
- Division of Cardiovascular Medicine, Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Maya Guglin
- Division of Cardiovascular Medicine, Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Kenneth S Campbell
- Division of Cardiovascular Medicine, Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Magdi H Yacoub
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Pieter de Tombe
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
- Heart Science Centre, Magdi Yacoub Institute, Harefield Hospital, London UB9 6JH, UK
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, USA
| | - Steven B Marston
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
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11
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McDonald KS, Hanft LM, Robinett JC, Guglin M, Campbell KS. Regulation of Myofilament Contractile Function in Human Donor and Failing Hearts. Front Physiol 2020; 11:468. [PMID: 32523542 PMCID: PMC7261867 DOI: 10.3389/fphys.2020.00468] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/16/2020] [Indexed: 01/14/2023] Open
Abstract
Heart failure (HF) often includes changes in myocardial contractile function. This study addressed the myofibrillar basis for contractile dysfunction in failing human myocardium. Regulation of contractile properties was measured in cardiac myocyte preparations isolated from frozen, left ventricular mid-wall biopsies of donor (n = 7) and failing human hearts (n = 8). Permeabilized cardiac myocyte preparations were attached between a force transducer and a position motor, and both the Ca2+ dependence and sarcomere length (SL) dependence of force, rate of force, loaded shortening, and power output were measured at 15 ± 1°C. The myocyte preparation size was similar between groups (donor: length 148 ± 10 μm, width 21 ± 2 μm, n = 13; HF: length 131 ± 9 μm, width 23 ± 1 μm, n = 16). The maximal Ca2+-activated isometric force was also similar between groups (donor: 47 ± 4 kN⋅m-2; HF: 44 ± 5 kN⋅m-2), which implicates that previously reported force declines in multi-cellular preparations reflect, at least in part, tissue remodeling. Maximal force development rates were also similar between groups (donor: k tr = 0.60 ± 0.05 s-1; HF: k tr = 0.55 ± 0.04 s-1), and both groups exhibited similar Ca2+ activation dependence of k tr values. Human cardiac myocyte preparations exhibited a Ca2+ activation dependence of loaded shortening and power output. The peak power output normalized to isometric force (PNPO) decreased by ∼12% from maximal Ca2+ to half-maximal Ca2+ activations in both groups. Interestingly, the SL dependence of PNPO was diminished in failing myocyte preparations. During sub-maximal Ca2+ activation, a reduction in SL from ∼2.25 to ∼1.95 μm caused a ∼26% decline in PNPO in donor myocytes but only an ∼11% change in failing myocytes. These results suggest that altered length-dependent regulation of myofilament function impairs ventricular performance in failing human hearts.
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Affiliation(s)
- Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Laurin M. Hanft
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Joel C. Robinett
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Maya Guglin
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, United States
| | - Kenneth S. Campbell
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, United States
- Department of Physiology, University of Kentucky, Lexington, KY, United States
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Defining decreased protein succinylation of failing human cardiac myofibrils in ischemic cardiomyopathy. J Mol Cell Cardiol 2019; 138:304-317. [PMID: 31836543 DOI: 10.1016/j.yjmcc.2019.11.159] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/23/2019] [Accepted: 11/27/2019] [Indexed: 12/20/2022]
Abstract
Succinylation is a post-translational modification of protein lysine residues with succinyl groups derived from succinyl CoA. Succinylation is considered a significant post-translational modification with the potential to impact protein function which is highly conserved across numerous species. The role of succinylation in the heart, especially in heart failure and myofibril mechanics, remains largely unexplored. Mechanical parameters were measured in myofibrils isolated from failing hearts of ischemic cardiomyopathy patients and non-failing donor controls. We employed mass spectrometry to quantify differential protein expression in myofibrils from failing ischemic cardiomyopathy hearts compared to non-failing hearts. In addition, we combined peptide enrichment by immunoprecipitation with liquid chromatography tandem mass spectrometry to quantitatively analyze succinylated lysine residues in these myofibrils. Several key parameters of sarcomeric mechanical interactions were altered in myofibrils isolated from failing ischemic cardiomyopathy hearts, including lower resting tension and a faster rate of activation. Of the 100 differentially expressed proteins, 46 showed increased expression in ischemic heart failure, while 54 demonstrated decreased expression in ischemic heart failure. Our quantitative succinylome analysis identified a total of 572 unique succinylated lysine sites located on 181 proteins, with 307 significantly changed succinylation events. We found that 297 succinyl-Lys demonstrated decreased succinylation on 104 proteins, while 10 residues demonstrated increased succinylation on 4 proteins. Investigating succinyl CoA generation, enzyme activity assays demonstrated that α-ketoglutarate dehydrogenase and succinate dehydrogenase activities were significantly decreased in ischemic heart failure. An activity assay for succinyl CoA synthetase demonstrated a significant increase in ischemic heart failure. Taken together, our findings support the hypothesis that succinyl CoA production is decreased and succinyl CoA turnover is increased in ischemic heart failure, potentially resulting in an overall decrease in the mitochondrial succinyl CoA pool, which may contribute to decreased myofibril protein succinylation in heart failure.
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Kachooei E, Cordina NM, Brown LJ. Constructing a structural model of troponin using site-directed spin labeling: EPR and PRE-NMR. Biophys Rev 2019; 11:621-639. [PMID: 31321733 PMCID: PMC6682194 DOI: 10.1007/s12551-019-00568-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/24/2019] [Indexed: 02/05/2023] Open
Abstract
The relative ease of introducing a paramagnetic species onto a protein, and advances in electron paramagnetic resonance (EPR) over the past two decades, have established spin labeling as a vital structural biology technique for revealing the functional workings of the troponin muscle regulatory complex-an ~80 kDa heterotrimeric protein switch for turning on striated muscle contraction. Through the site-directed spin labeling (SDSL) of cysteine residues at key sites in troponin, a molecular-level understanding of the troponin muscle regulatory system across all levels of structural hierarchy has been achieved. Through the application of EPR, mobility and accessibility trends in the EPR signals of the spin labels attached to consecutive residues can reveal the secondary structure of troponin elements and also help map the interaction between subunits. Distance restraints calculated from the interspin interactions between spin label pairs have helped with building a structural model of the troponin complex. Further, when SDSL is paired with NMR, paramagnetic relaxation enhancement (PRE)-NMR has been used to obtain high-resolution structural detail for both intra- and interdomain interactions in troponin and revealed details of protein conformational changes and dynamics accompanying troponin function. In this review, we provide an overview of the SDSL labeling methodology and its application towards building a dynamic structural model of the multi-subunit troponin complex which details the calcium-induced conformational changes intimately linked to muscle regulation. We also describe how the SDSL method, in conjunction with EPR or NMR, can be used to obtain insights into structural perturbations to troponin caused by disease-causing mutations.
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Affiliation(s)
- Ehsan Kachooei
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - Nicole M Cordina
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - Louise J Brown
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.
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van der Velden J, Stienen GJM. Cardiac Disorders and Pathophysiology of Sarcomeric Proteins. Physiol Rev 2019; 99:381-426. [PMID: 30379622 DOI: 10.1152/physrev.00040.2017] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The sarcomeric proteins represent the structural building blocks of heart muscle, which are essential for contraction and relaxation. During recent years, it has become evident that posttranslational modifications of sarcomeric proteins, in particular phosphorylation, tune cardiac pump function at rest and during exercise. This delicate, orchestrated interaction is also influenced by mutations, predominantly in sarcomeric proteins, which cause hypertrophic or dilated cardiomyopathy. In this review, we follow a bottom-up approach starting from a description of the basic components of cardiac muscle at the molecular level up to the various forms of cardiac disorders at the organ level. An overview is given of sarcomere changes in acquired and inherited forms of cardiac disease and the underlying disease mechanisms with particular reference to human tissue. A distinction will be made between the primary defect and maladaptive/adaptive secondary changes. Techniques used to unravel functional consequences of disease-induced protein changes are described, and an overview of current and future treatments targeted at sarcomeric proteins is given. The current evidence presented suggests that sarcomeres not only form the basis of cardiac muscle function but also represent a therapeutic target to combat cardiac disease.
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Affiliation(s)
- Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Ger J M Stienen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
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Functional cardiac orexin receptors: role of orexin-B/orexin 2 receptor in myocardial protection. Clin Sci (Lond) 2018; 132:2547-2564. [PMID: 30467191 PMCID: PMC6365625 DOI: 10.1042/cs20180150] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 11/20/2018] [Accepted: 11/22/2018] [Indexed: 01/25/2023]
Abstract
Orexins/hypocretins exert cardiovascular effects which are centrally mediated. In the present study, we tested whether orexins and their receptors may also act in an autocrine/paracrine manner in the heart exerting direct effects. Quantitative reverse transcription-PCR (RT-PCR), immunohistochemical and Western blot analyses revealed that the rat heart expresses orexins and orexin receptors (OXR). In isolated rat cardiomyocytes, only orexin-B (OR-B) caused an increase in contractile shortening, independent of diastolic or systolic calcium levels. A specific orexin receptor-2 (OX2R) agonist ([Ala11, d-Leu15]-Orexin B) exerted similar effects as OR-B, whereas a specific orexin receptor-1 (OX1R) antagonist (SB-408124) did not alter the responsiveness of OR-B. Treatment of the same model with OR-B resulted in a dose-dependent increase in myosin light chain and troponin-I (TnI) phosphorylation. Following ischaemia/reperfusion in the isolated Langendorff perfused rat heart model, OR-B, but not OR-A, exerts a cardioprotective effect; mirrored in an in vivo model as well. Unlike OR-A, OR-B was also able to induce extracellular signal-regulated kinase (ERK) 1/2 (ERK1/2) and Akt phosphorylation in rat myocardial tissue and ERK1/2 phosphorylation in human heart samples. These findings were further corroborated in an in vivo rat model. In human subjects with heart failure, there is a significant negative correlation between the expression of OX2R and the severity of the disease clinical symptoms, as assessed by the New York Heart Association (NYHA) functional classification. Collectively, we provide evidence of a distinct orexin system in the heart that exerts a cardioprotective role via an OR-B/OX2R pathway.
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Vikhorev PG, Vikhoreva NN. Cardiomyopathies and Related Changes in Contractility of Human Heart Muscle. Int J Mol Sci 2018; 19:ijms19082234. [PMID: 30065175 PMCID: PMC6121228 DOI: 10.3390/ijms19082234] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 07/22/2018] [Accepted: 07/27/2018] [Indexed: 02/07/2023] Open
Abstract
About half of hypertrophic and dilated cardiomyopathies cases have been recognized as genetic diseases with mutations in sarcomeric proteins. The sarcomeric proteins are involved in cardiomyocyte contractility and its regulation, and play a structural role. Mutations in non-sarcomeric proteins may induce changes in cell signaling pathways that modify contractile response of heart muscle. These facts strongly suggest that contractile dysfunction plays a central role in initiation and progression of cardiomyopathies. In fact, abnormalities in contractile mechanics of myofibrils have been discovered. However, it has not been revealed how these mutations increase risk for cardiomyopathy and cause the disease. Much research has been done and still much is being done to understand how the mechanism works. Here, we review the facts of cardiac myofilament contractility in patients with cardiomyopathy and heart failure.
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Affiliation(s)
- Petr G Vikhorev
- National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
| | - Natalia N Vikhoreva
- Heart Science Centre, Magdi Yacoub Institute, Harefield Hospital, London UB9 6JH, UK.
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17
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Abstract
Diabetes is a major risk factor for the development of heart failure. One of the hallmarks of diabetes is insulin resistance associated with hyperinsulinemia. The literature shows that insulin and adrenergic signaling is intimately linked to each other; however, whether and how insulin may modulate cardiac adrenergic signaling and cardiac function remains unknown. Notably, recent studies have revealed that insulin receptor and β2 adrenergic receptor (β2AR) forms a membrane complex in animal hearts, bringing together the direct contact between 2 receptor signaling systems, and forming an integrated and dynamic network. Moreover, insulin can drive cardiac adrenergic desensitization via protein kinase A and G protein-receptor kinases phosphorylation of the β2AR, which compromises adrenergic regulation of cardiac contractile function. In this review, we will explore the current state of knowledge linking insulin and G protein-coupled receptor signaling, especially β-adrenergic receptor signaling in the heart, with emphasis on molecular insights regarding its role in diabetic cardiomyopathy.
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Alquézar-Arbé A, Sionis A, Ordoñez-Llanos J. Cardiac troponins: 25 years on the stage and still improving their clinical value. Crit Rev Clin Lab Sci 2017; 54:551-571. [PMID: 29226754 DOI: 10.1080/10408363.2017.1410777] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Twenty-five years ago, non-isotopic immunoassays for measuring the cardiac specific isoforms of troponin I (cTnI) and T (cTnT) were developed. Both biomarkers radically changed the diagnosis, prognosis, and therapy indication of acute coronary syndromes (ACS) and, particularly, of myocardial infarction (MI). However, cardiac troponins (cTn) rapidly demonstrated their usefulness in other cardiac and non-cardiac conditions, a part of the ischemic coronary diseases. Consequently, the number of patients to be tested for cTn and the number of tests requested to clinical laboratories sharply increased. Though the manufacturers continuously improved the analytical characteristics of the first cTn assays and produced different cTn assay "generations", the universal definition of myocardial infarction required less-than-available analytical imprecision at the cTn concentration used to assess MI (i.e. the 99th reference percentile). To address the clinical requirements, manufacturers developed the high-sensitivity cTn (hs-cTn) assays that allow to measure the 99th reference percentile with adequate precision, to detect cTn in many healthy subjects and, hence, to calculate the hs-cTn biological variation and especially to observe in very short time intervals serial differences in hs-cTn attributable to cardiac ischemia. Since the number of patients attending the emergency departments (ED) for a suspected ACS or MI is increasing, the improved properties of hs-cTn assays, allowing faster and safer patient assessment, will help to alleviate the sometimes overcrowded EDs. However, there are many biological, analytical, and clinical factors that can influence the true hs-cTn values of a patient. Clinicians and laboratory professionals should know about them for the best interpretation of the otherwise largely useful hs-cTn measurements. In conclusion, 25 years after their introduction for clinical use, "cTn are still on the stage and improving their clinical value".
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Affiliation(s)
| | - Alessandro Sionis
- b Cardiology Department, Acute and Intensive Cardiac Care Unit, IIB-Sant Pau, CIBER-CV , Hospital de la Santa Creu i Sant Pau , Barcelona , Spain.,c Faculty of Medicine , Universitat de Barcelona , Barcelona , Spain
| | - Jorge Ordoñez-Llanos
- d Clinical Biochemistry Department , Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau , Barcelona , Spain.,e Biochemistry and Molecular Biology Department , Universitat Autònoma , Barcelona , Spain.,f Task Force on Clinical Application of Cardiac Biomarkers , International Federation of Clinical Chemistry , Milan , Italy
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19
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Soetkamp D, Raedschelders K, Mastali M, Sobhani K, Bairey Merz CN, Van Eyk J. The continuing evolution of cardiac troponin I biomarker analysis: from protein to proteoform. Expert Rev Proteomics 2017; 14:973-986. [PMID: 28984473 DOI: 10.1080/14789450.2017.1387054] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION The troponin complex consists of three proteins that fundamentally couple excitation with contraction. Circulating cardiac-specific Troponin I (cTnI) serves as diagnostic biomarker tools for risk stratification of acute coronary syndromes and acute myocardial infarction (MI). Within the heart, cTnI oscillates between inactive and active conformations to either block or disinhibit actinomyosin formation. This molecular mechanism is fine-tuned through extensive protein modifications whose profiles are maladaptively altered with co-morbidities including hypertrophic cardiomyopathy, diabetes, and heart failure. Technological advances in analytical platforms over the last decade enable routine baseline cTnI analysis in patients without cardiovascular complications, and hold potential to expand cTnI readouts that include modified cTnI proteoforms. Areas covered: This review covers the current state, advances, and prospects of analytical platforms that now enable routine baseline cTnI analysis in patients. In parallel, improved mass spectrometry instrumentation and workflows already reveal an array of modified cTnI proteoforms with promising diagnostic implications. Expert commentary: New analytical capabilities provide clinicians and researchers with an opportunity to address important questions surrounding circulating cTnI in the improved diagnosis of specific patient cohorts. These techniques also hold considerable promise for new predictive and prescriptive applications for individualized profiling and improve patient care.
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Affiliation(s)
- Daniel Soetkamp
- a Heart Institute , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - Koen Raedschelders
- a Heart Institute , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - Mitra Mastali
- a Heart Institute , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - Kimia Sobhani
- b Pathology and Laboratory Medicine , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - C Noel Bairey Merz
- c Women's Heart Center , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - Jennifer Van Eyk
- a Heart Institute , Cedars-Sinai Medical Center , Los Angeles , CA , USA
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20
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Krasniqi X, Berisha B, Gashi M, Koçinaj D, Jashari F, Vincelj J. Influence of apelin-12 on troponin levels and the rate of MACE in STEMI patients. BMC Cardiovasc Disord 2017; 17:195. [PMID: 28728608 PMCID: PMC5520283 DOI: 10.1186/s12872-017-0633-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/14/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND During acute myocardial infarction, phosphorylated TnI levels, Ca2+ sensitivity and ATPase activity are decreased in the myocardium, and the subsequent elevation in Ca2+ levels activates protease I (caplain I), leading to the proteolytic degradation of troponins. Concurrently, the levels of apelin and APJ expression are increased by limiting myocardial injury. METHODS In this prospective observational study, 100 consecutive patients with ST-elevation acute myocardial infarction were included. Patients meeting the following criteria were included in our study: (1) continuous chest pain lasting for >30 min, (2) observation of ST-segment elevation of more than 2 mm in two adjacent leads by electrocardiography (ECG), (3) increased cardiac troponin I levels, and (4) patients who underwent reperfusion therapy. We evaluated the levels of apelin-12 and troponin I on the first and seventh days after reperfusion therapy in all patients. RESULTS Apelin-12 was inversely correlated with troponin I levels (Spearman's correlation = -0.40) with a p value <0.001. There was variability in the apelin values on the seventh day (Kruskal-Wallis test) based on major adverse cardiac events (MACE) (p = 0.012). Using ROC curve analyses, a cut-off value of >2.2 for the association of apelin with MACE was determined, and the AUC was 0.71 (95% CI, 0.58-0.84). Survival analysis using the Kaplan-Meier method showed a lower rate of MACE among patients with apelin levels >2.2 (p = 0.002), and the ROC curve analysis showed a statistically significant difference in the area under the curve (p = 0.004). CONCLUSION The influence of apelin levels on troponin levels in the acute phase of STEMI is inversely correlated, whereas in the non-acute phase, low apelin values were associated with a high rate of MACE.
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Affiliation(s)
- Xhevdet Krasniqi
- University Clinical Center of Kosova, Mother Theresa n.n, 10000, Prishtina, Republic of Kosovo.
| | - Blerim Berisha
- University Clinical Center of Kosova, Mother Theresa n.n, 10000, Prishtina, Republic of Kosovo
| | - Masar Gashi
- University Clinical Center of Kosova, Mother Theresa n.n, 10000, Prishtina, Republic of Kosovo
| | - Dardan Koçinaj
- University Clinical Center of Kosova, Mother Theresa n.n, 10000, Prishtina, Republic of Kosovo
| | - Fisnik Jashari
- University Clinical Center of Kosova, Mother Theresa n.n, 10000, Prishtina, Republic of Kosovo
| | - Josip Vincelj
- Clinical Hospital Dubrava, Zagreb, Republic of Croatia
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Morphological and immunobiochemical analysis of the liver in L-arginine induced experimental chronic pancreatitis. Pancreatology 2017; 17:247-254. [PMID: 28131523 DOI: 10.1016/j.pan.2017.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 12/21/2016] [Accepted: 01/19/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND Clinical evidence indicates that hepatic abnormalities in patients with chronic pancreatitis are not uncommon. Here we aimed to study the possible association between liver and pancreatic damage in a recently described experimental mouse model of CP. METHODS The severity of the damage to pancreas, liver and other organs was assessed by biochemical markers and histopathology. The methods applied included Hematoxylin Eosin staining, electron microscope examination, biochemical measurements, RT-PCR, ELISA, and the correlations among some of the parameters contributing to these changes were statistically analyzed. RESULTS The hepatic aberrations were mainly represented by mild infiltration of inflammatory cells in portal triad and congestion of central vein of liver, and the main features of drug-induced hepatotoxicity could not be observed. Severe fibrosis of pancreatic tissue was noticed in experimental group, and the existence of multiple organ injuries was also seen under the microscope. Hepatic pathologic scores were positively correlated with those from the corresponding pancreatic specimens (r = 0.72, P < 0.01). TGF-β1 protein levels significantly elevated both in the test pancreas and liver (P < 0.05) and these values were positively correlated (r = 0.86, P < 0.01). The level of interleukin-1β was increased in the serum and tissue of the liver. In addition, cardiac troponin (Tn-I) level not only significantly increased in myocardial homogenates (P < 0.05) but also was positively correlated with the corresponding pathologic score of the liver (r = 0.88, P < 0.01). CONCLUSION The liver aberrations might be associated with L-arginine induced chronic pancreatitis.
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Najafi A, Sequeira V, Helmes M, Bollen IAE, Goebel M, Regan JA, Carrier L, Kuster DWD, Van Der Velden J. Selective phosphorylation of PKA targets after β-adrenergic receptor stimulation impairs myofilament function in Mybpc3-targeted HCM mouse model. Cardiovasc Res 2016; 110:200-14. [PMID: 26825555 DOI: 10.1093/cvr/cvw026] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 01/22/2016] [Indexed: 12/19/2022] Open
Abstract
AIMS Hypertrophic cardiomyopathy (HCM) has been associated with reduced β-adrenergic receptor (β-AR) signalling, leading downstream to a low protein kinase A (PKA)-mediated phosphorylation. It remained undefined whether all PKA targets will be affected similarly by diminished β-AR signalling in HCM. We aimed to investigate the role of β-AR signalling on regulating myofilament and calcium handling in an HCM mouse model harbouring a gene mutation (G > A transition on the last nucleotide of exon 6) in Mybpc3 encoding cardiac myosin-binding protein C. METHODS AND RESULTS Cardiomyocyte contractile properties and phosphorylation state were measured in left ventricular permeabilized and intact cardiomyocytes isolated from heterozygous (HET) or homozygous (KI) Mybpc3-targeted knock-in mice. Significantly higher myofilament Ca²⁺sensitivity and passive tension were detected in KI mice, which were normalized after PKA treatment. Loaded intact cardiomyocyte force-sarcomere length relation was impaired in both HET and KI mice, suggesting a reduced length-dependent activation. Unloaded cardiomyocyte function revealed an impaired myofilament contractile response to isoprenaline (ISO) in KI, whereas the calcium-handling response to ISO was maintained. This disparity was explained by an attenuated increase in cardiac troponin I (cTnI) phosphorylation in KI, whereas the increase in phospholamban (PLN) phosphorylation was maintained to wild-type values. CONCLUSION These data provide evidence that in the KI HCM mouse model, β-AR stimulation leads to preferential PKA phosphorylation of PLN over cTnI, resulting in an impaired inotropic and lusitropic response.
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Affiliation(s)
- Aref Najafi
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
| | - Vasco Sequeira
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Michiel Helmes
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Ilse A E Bollen
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Max Goebel
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Jessica A Regan
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Lucie Carrier
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Germany
| | - Diederik W D Kuster
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands
| | - Jolanda Van Der Velden
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center Amsterdam, Netherlands ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
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Huang W, Szczesna-Cordary D. Molecular mechanisms of cardiomyopathy phenotypes associated with myosin light chain mutations. J Muscle Res Cell Motil 2015; 36:433-45. [PMID: 26385864 DOI: 10.1007/s10974-015-9423-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/10/2015] [Indexed: 12/14/2022]
Abstract
We discuss here the potential mechanisms of action associated with hypertrophic (HCM) or dilated (DCM) cardiomyopathy causing mutations in the myosin regulatory (RLC) and essential (ELC) light chains. Specifically, we focus on four HCM mutations: RLC-A13T, RLC-K104E, ELC-A57G and ELC-M173V, and one DCM RLC-D94A mutation shown by population studies to cause different cardiomyopathy phenotypes in humans. Our studies indicate that RLC and ELC mutations lead to heart disease through different mechanisms with RLC mutations triggering alterations of the secondary structure of the RLC which further affect the structure and function of the lever arm domain and impose changes in the cross bridge cycling rates and myosin force generation ability. The ELC mutations exert their detrimental effects through changes in the interaction of the N-terminus of ELC with actin altering the cross talk between the thick and thin filaments and ultimately resulting in an altered force-pCa relationship. We also discuss the effect of mutations on myosin light chain phosphorylation. Exogenous myosin light chain phosphorylation and/or pseudo-phosphorylation were explored as potential rescue tools to treat hypertrophy-related cardiac phenotypes.
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Affiliation(s)
- Wenrui Huang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
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The R21C Mutation in Cardiac Troponin I Imposes Differences in Contractile Force Generation between the Left and Right Ventricles of Knock-In Mice. BIOMED RESEARCH INTERNATIONAL 2015; 2015:742536. [PMID: 25961037 PMCID: PMC4415466 DOI: 10.1155/2015/742536] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/16/2014] [Accepted: 12/19/2014] [Indexed: 01/20/2023]
Abstract
We investigated the effect of the hypertrophic cardiomyopathy-linked R21C (arginine to cysteine) mutation in human cardiac troponin I (cTnI) on the contractile properties and myofilament protein phosphorylation in papillary muscle preparations from left (LV) and right (RV) ventricles of homozygous R21C(+/+) knock-in mice. The maximal steady-state force was significantly reduced in skinned papillary muscle strips from the LV compared to RV, with the latter displaying the level of force observed in LV or RV from wild-type (WT) mice. There were no differences in the Ca(2+) sensitivity between the RV and LV of R21C(+/+) mice; however, the Ca(2+) sensitivity of force was higher in RV-R21C(+/+) compared with RV-WT and lower in LV- R21C(+/+) compared with LV-WT. We also observed partial loss of Ca(2+) regulation at low [Ca(2+)]. In addition, R21C(+/+)-KI hearts showed no Ser23/24-cTnI phosphorylation compared to LV or RV of WT mice. However, phosphorylation of the myosin regulatory light chain (RLC) was significantly higher in the RV versus LV of R21C(+/+) mice and versus LV and RV of WT mice. The difference in RLC phosphorylation between the ventricles of R21C(+/+) mice likely contributes to observed differences in contractile force and the lower tension monitored in the LV of HCM mice.
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Arentz G, Weiland F, Oehler MK, Hoffmann P. State of the art of 2D DIGE. Proteomics Clin Appl 2015; 9:277-88. [DOI: 10.1002/prca.201400119] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/13/2014] [Accepted: 11/10/2014] [Indexed: 02/04/2023]
Affiliation(s)
- Georgia Arentz
- School of Molecular and Biomedical Science; Adelaide Proteomics Centre; The University of Adelaide; Adelaide Australia
| | - Florian Weiland
- School of Molecular and Biomedical Science; Adelaide Proteomics Centre; The University of Adelaide; Adelaide Australia
| | - Martin K. Oehler
- School of Paediatrics and Reproductive Health; Research Centre for Reproductive Health; Robinson Institute; University of Adelaide; SA Australia
- Department of Gynaecological Oncology; Royal Adelaide Hospital; Adelaide SA Australia
| | - Peter Hoffmann
- School of Molecular and Biomedical Science; Adelaide Proteomics Centre; The University of Adelaide; Adelaide Australia
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Papp Z, van der Velden J, Borbély A, Édes I, Stienen GJM. Altered myocardial force generation in end-stage human heart failure. ESC Heart Fail 2015; 1:160-165. [PMID: 28834631 DOI: 10.1002/ehf2.12020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/07/2014] [Accepted: 11/17/2014] [Indexed: 11/06/2022] Open
Abstract
AIMS This study aimed to elucidate the molecular background of increased Ca2+ sensitivity of force production in cardiomyocytes of end-stage human heart failure. METHODS AND RESULTS Ca2+ -activated isometric force and the cross-bridge specific rate of force redevelopment (ktr ) were determined in Triton-skinned myocytes from end-stage failing and non-failing donor hearts. Measurements (control: pH 7.2, 0 mM inorganic phosphate (Pi )) were performed under test conditions that probed either the Ca2+ -regulatory function of the thin filaments (pH 6.5), the kinetics of the actin-myosin cross-bridge cycle (10 mM Pi ), or both (pH 6.5, 10 mM Pi ). The control maximal Ca2+ -activated force (Fo ) and ktrmax did not differ between failing and non-failing myocytes. At submaximal [Ca2+ ], however, both force and ktr were higher in failing than in donor myocytes. The difference in the Ca2+ sensitivities of force production was preserved when the thin filament regulatory function was perturbed by acidosis (pH 6.5) but was abolished by cross-bridge modulation (i.e. by Pi ) both at pH 7.2 and at pH 6.5. Pi induced a larger reduction in force but a smaller increase in ktr in the failing myocytes than in the non-failing myocytes at submaximal [Ca2+ ]. CONCLUSION The enhanced Pi sensitivity of the actin-myosin interaction suggests that the Pi release step of the actin-myosin cross-bridge cycle is modified during end-stage human heart failure. This might be of functional importance when Pi accumulates (e.g. during cardiac ischaemia). Moreover, this alteration can influence cardiac energetics and the clinical efficacy of sarcomere targeted agents in human heart failure.
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Affiliation(s)
- Zoltán Papp
- Division of Clinical Physiology, Institute of Cardiology, University of Debrecen, 4032, Debrecen, Hungary
| | - Jolanda van der Velden
- Laboratory for Physiology, Institute of Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, Netherlands
| | - Attila Borbély
- Division of Clinical Physiology, Institute of Cardiology, University of Debrecen, 4032, Debrecen, Hungary
| | - István Édes
- Division of Clinical Physiology, Institute of Cardiology, University of Debrecen, 4032, Debrecen, Hungary
| | - Ger J M Stienen
- Laboratory for Physiology, Institute of Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, Netherlands
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