1
|
Donkervoort S, van de Locht M, Ronchi D, Reunert J, McLean CA, Zaki M, Orbach R, de Winter JM, Conijn S, Hoomoedt D, Neto OLA, Magri F, Viaene AN, Foley AR, Gorokhova S, Bolduc V, Hu Y, Acquaye N, Napoli L, Park JH, Immadisetty K, Miles LB, Essawi M, McModie S, Ferreira LF, Zanotti S, Neuhaus SB, Medne L, ElBagoury N, Johnson KR, Zhang Y, Laing NG, Davis MR, Bryson-Richardson RJ, Hwee DT, Hartman JJ, Malik FI, Kekenes-Huskey PM, Comi GP, Sharaf-Eldin W, Marquardt T, Ravenscroft G, Bönnemann CG, Ottenheijm CAC. Pathogenic TNNI1 variants disrupt sarcomere contractility resulting in hypo- and hypercontractile muscle disease. Sci Transl Med 2024; 16:eadg2841. [PMID: 38569017 DOI: 10.1126/scitranslmed.adg2841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 03/11/2024] [Indexed: 04/05/2024]
Abstract
Troponin I (TnI) regulates thin filament activation and muscle contraction. Two isoforms, TnI-fast (TNNI2) and TnI-slow (TNNI1), are predominantly expressed in fast- and slow-twitch myofibers, respectively. TNNI2 variants are a rare cause of arthrogryposis, whereas TNNI1 variants have not been conclusively established to cause skeletal myopathy. We identified recessive loss-of-function TNNI1 variants as well as dominant gain-of-function TNNI1 variants as a cause of muscle disease, each with distinct physiological consequences and disease mechanisms. We identified three families with biallelic TNNI1 variants (F1: p.R14H/c.190-9G>A, F2 and F3: homozygous p.R14C), resulting in loss of function, manifesting with early-onset progressive muscle weakness and rod formation on histology. We also identified two families with a dominantly acting heterozygous TNNI1 variant (F4: p.R174Q and F5: p.K176del), resulting in gain of function, manifesting with muscle cramping, myalgias, and rod formation in F5. In zebrafish, TnI proteins with either of the missense variants (p.R14H; p.R174Q) incorporated into thin filaments. Molecular dynamics simulations suggested that the loss-of-function p.R14H variant decouples TnI from TnC, which was supported by functional studies showing a reduced force response of sarcomeres to submaximal [Ca2+] in patient myofibers. This contractile deficit could be reversed by a slow skeletal muscle troponin activator. In contrast, patient myofibers with the gain-of-function p.R174Q variant showed an increased force to submaximal [Ca2+], which was reversed by the small-molecule drug mavacamten. Our findings demonstrated that TNNI1 variants can cause muscle disease with variant-specific pathomechanisms, manifesting as either a hypo- or a hypercontractile phenotype, suggesting rational therapeutic strategies for each mechanism.
Collapse
Affiliation(s)
- Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Martijn van de Locht
- Department of Physiology, Amsterdam UMC (location VUmc), Amsterdam, 1081 HV Netherlands
| | - Dario Ronchi
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, Milan, 20135, Italy
| | - Janine Reunert
- Department of General Pediatrics, University of Münster, Münster, 48149, Germany
| | - Catriona A McLean
- Department of Anatomical Pathology, Alfred Hospital, Melbourne, Victoria, 3004, Australia
- Faculty of Medicine, Nursing, and Health Sciences, Monash University, Melbourne, Victoria, 3168, Australia
| | - Maha Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, 12622, Egypt
| | - Rotem Orbach
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Josine M de Winter
- Department of Physiology, Amsterdam UMC (location VUmc), Amsterdam, 1081 HV Netherlands
| | - Stefan Conijn
- Department of Physiology, Amsterdam UMC (location VUmc), Amsterdam, 1081 HV Netherlands
| | - Daan Hoomoedt
- Department of Physiology, Amsterdam UMC (location VUmc), Amsterdam, 1081 HV Netherlands
| | - Osorio Lopes Abath Neto
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Francesca Magri
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, 20122, Italy
| | - Angela N Viaene
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, 19104 PA, USA
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Svetlana Gorokhova
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Medical Genetics, Timone Children's Hospital, APHM, Marseille, 13005, France
- INSERM, U1251-MMG, Aix-Marseille Université, Marseille, 13009, France
| | - Véronique Bolduc
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ying Hu
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nicole Acquaye
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Laura Napoli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, 20122, Italy
| | - Julien H Park
- Department of General Pediatrics, University Hospital Münster, Münster, 48149 Germany
| | - Kalyan Immadisetty
- Department of Cell and Molecular Physiology, Loyola University, Chicago, IL 60153, USA
| | - Lee B Miles
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - Mona Essawi
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, 12622, Egypt
| | - Salar McModie
- Department of Neurology, Alfred Health, Melbourne, Victoria, 3004, Australia
| | - Leonardo F Ferreira
- Department of Physiology, Amsterdam UMC (location VUmc), Amsterdam, 1081 HV Netherlands
- Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Simona Zanotti
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, 20122, Italy
| | - Sarah B Neuhaus
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Livija Medne
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nagham ElBagoury
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, 12622, Egypt
| | - Kory R Johnson
- Bioinformatics Core, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yong Zhang
- Bioinformatics Core, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nigel G Laing
- Neurogenetics Unit, Department of Diagnostic Genomics, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia
- Centre for Medical Research University of Western Australia, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia
| | - Mark R Davis
- Neurogenetics Unit, Department of Diagnostic Genomics, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia
| | | | - Darren T Hwee
- Research and Development, Cytokinetics Inc., South San Francisco, CA 94080, USA
| | - James J Hartman
- Research and Development, Cytokinetics Inc., South San Francisco, CA 94080, USA
| | - Fady I Malik
- Research and Development, Cytokinetics Inc., South San Francisco, CA 94080, USA
| | | | - Giacomo Pietro Comi
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, Milan, 20135, Italy
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, 20122, Italy
| | - Wessam Sharaf-Eldin
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, 12622, Egypt
| | - Thorsten Marquardt
- Department of General Pediatrics, University of Münster, Münster, 48149, Germany
| | - Gianina Ravenscroft
- Centre for Medical Research University of Western Australia, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Coen A C Ottenheijm
- Department of Physiology, Amsterdam UMC (location VUmc), Amsterdam, 1081 HV Netherlands
| |
Collapse
|
2
|
Abrams ST, Alhamdi Y, Zi M, Guo F, Du M, Wang G, Cartwright EJ, Toh CH. Extracellular Histone-Induced Protein Kinase C Alpha Activation and Troponin Phosphorylation Is a Potential Mechanism of Cardiac Contractility Depression in Sepsis. Int J Mol Sci 2023; 24:ijms24043225. [PMID: 36834636 PMCID: PMC9967552 DOI: 10.3390/ijms24043225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/29/2023] [Accepted: 02/01/2023] [Indexed: 02/10/2023] Open
Abstract
Reduction in cardiac contractility is common in severe sepsis. However, the pathological mechanism is still not fully understood. Recently it has been found that circulating histones released after extensive immune cell death play important roles in multiple organ injury and disfunction, particularly in cardiomyocyte injury and contractility reduction. How extracellular histones cause cardiac contractility depression is still not fully clear. In this work, using cultured cardiomyocytes and a histone infusion mouse model, we demonstrate that clinically relevant histone concentrations cause significant increases in intracellular calcium concentrations with subsequent activation and enriched localization of calcium-dependent protein kinase C (PKC) α and βII into the myofilament fraction of cardiomyocytes in vitro and in vivo. Furthermore, histones induced dose-dependent phosphorylation of cardiac troponin I (cTnI) at the PKC-regulated phosphorylation residues (S43 and T144) in cultured cardiomyocytes, which was also confirmed in murine cardiomyocytes following intravenous histone injection. Specific inhibitors against PKCα and PKCβII revealed that histone-induced cTnI phosphorylation was mainly mediated by PKCα activation, but not PKCβII. Blocking PKCα also significantly abrogated histone-induced deterioration in peak shortening, duration and the velocity of shortening, and re-lengthening of cardiomyocyte contractility. These in vitro and in vivo findings collectively indicate a potential mechanism of histone-induced cardiomyocyte dysfunction driven by PKCα activation with subsequent enhanced phosphorylation of cTnI. These findings also indicate a potential mechanism of clinical cardiac dysfunction in sepsis and other critical illnesses with high levels of circulating histones, which holds the potential translational benefit to these patients by targeting circulating histones and downstream pathways.
Collapse
Affiliation(s)
- Simon T. Abrams
- Department of Clinical Infection Microbiology and Immunology, University of Liverpool, Liverpool L69 7BE, UK
- Coagulation Department, Liverpool University Hospitals NHS Foundation Trust, Liverpool L7 8XP, UK
| | - Yasir Alhamdi
- Department of Clinical Infection Microbiology and Immunology, University of Liverpool, Liverpool L69 7BE, UK
- Sheffield Teaching Hospital NHS Foundation Trust, Sheffield S5 7AU, UK
| | - Min Zi
- Institute of Cardiovascular Sciences, Centre for Cardiac Research, University of Manchester, Manchester M13 9PT, UK
| | - Fengmei Guo
- Department of Clinical Infection Microbiology and Immunology, University of Liverpool, Liverpool L69 7BE, UK
- The Medical School, Southeast University, Nanjing 210009, China
| | - Min Du
- Department of Clinical Infection Microbiology and Immunology, University of Liverpool, Liverpool L69 7BE, UK
| | - Guozheng Wang
- Department of Clinical Infection Microbiology and Immunology, University of Liverpool, Liverpool L69 7BE, UK
- Coagulation Department, Liverpool University Hospitals NHS Foundation Trust, Liverpool L7 8XP, UK
- Correspondence: (G.W.); (C.-H.T.)
| | - Elizabeth J. Cartwright
- Institute of Cardiovascular Sciences, Centre for Cardiac Research, University of Manchester, Manchester M13 9PT, UK
| | - Cheng-Hock Toh
- Department of Clinical Infection Microbiology and Immunology, University of Liverpool, Liverpool L69 7BE, UK
- Roald Dahl Haemostasis & Thrombosis Centre, Royal Liverpool University Hospital, Liverpool L7 8XP, UK
- Correspondence: (G.W.); (C.-H.T.)
| |
Collapse
|
3
|
Greenman AC, Diffee GM, Power AS, Wilkins GT, Gold OMS, Erickson JR, Baldi JC. Increased myofilament calcium sensitivity is associated with decreased cardiac troponin I phosphorylation in the diabetic rat heart. Exp Physiol 2021; 106:2235-2247. [PMID: 34605091 DOI: 10.1113/ep089730] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/23/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? In Zucker Diabetic Fatty rats, does cardiomyocyte myofilament function change through the time course of diabetes and what are the mechanisms behind alterations in calcium sensitivity? What is the main finding and its importance? Zucker Diabetic Fatty rats had increased myofilament calcium sensitivity and reduced phosphorylation at cardiac troponin I without differential O-GlcNAcylation. ABSTRACT The diabetic heart has impaired systolic and diastolic function independent of other comorbidities. The availability of calcium is altered, but does not fully explain the cardiac dysfunction seen in the diabetic heart. Thus, we explored if myofilament calcium regulation of contraction is altered while also categorizing the levels of phosphorylation and O-GlcNAcylation in the myofilaments. Calcium sensitivity (pCa50 ) was measured in Zucker Diabetic Fatty (ZDF) rat hearts at the initial stage of diabetes (12 weeks old) and after 8 weeks of uncontrolled hyperglycaemia (20 weeks old) and in non-diabetic (nDM) littermates. Skinned cardiomyocytes were connected to a capacitance-gauge transducer and a torque motor to measure force as a function of pCa (-log[Ca2+ ]). Fluorescent gel stain (ProQ Diamond) was used to measure total protein phosphorylation. Specific phospho-sites on cardiac troponin I (cTnI) and total cTnI O-GlcNAcylation were quantified using immunoblot. pCa50 was greater in both 12- and 20-week-old diabetic (DM) rats compared to nDM littermates (P = 0.0001). Total cTnI and cTnI serine 23/24 phosphorylation were lower in DM rats (P = 0.003 and P = 0.01, respectively), but cTnI O-GlcNAc protein expression was not different. pCa50 is greater in DM rats and corresponds with an overall reduction in cTnI phosphorylation. These findings indicate that myofilament calcium sensitivity is increased and cTnI phosphorylation is reduced in ZDF DM rats and suggests an important role for cTnI phosphorylation in the DM heart.
Collapse
Affiliation(s)
- Angela C Greenman
- Department of Medicine, Otago Medical School, University of Otago, Dunedin, New Zealand.,Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - Gary M Diffee
- Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Amelia S Power
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - Gerard T Wilkins
- Department of Medicine, Otago Medical School, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - Olivia M S Gold
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - Jeffrey R Erickson
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| | - James C Baldi
- Department of Medicine, Otago Medical School, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
| |
Collapse
|
4
|
Complex functionality of protein phosphatase 1 isoforms in the heart. Cell Signal 2021; 85:110059. [PMID: 34062239 DOI: 10.1016/j.cellsig.2021.110059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 05/21/2021] [Accepted: 05/28/2021] [Indexed: 02/04/2023]
Abstract
Protein phosphatase 1(PP1) is a key regulator of cardiac function through dephosphorylating serine/threonine residues within target proteins to oppose the function of protein kinases. Studies from failing hearts of animal models and human patients have demonstrated significant increase of PP1 activity in myocardium, while elevated PP1 activity in transgenic mice leads to cardiac dysfunction, suggesting that PP1 might be a therapeutic target to ameliorate cardiac dysfunction in failing hearts. In fact, cardiac overexpression of inhibitor 1, the endogenous inhibitor of PP1, increases cardiac contractility and suppresses heart failure progression. However, this notion of PP1 inhibition for heart failure treatment has been challenged by recent studies on the isoform-specific roles of PP1 in the heart. PP1 is a holoenzyme composed of catalytic subunits (PP1α, PP1β, or PP1γ) and regulatory proteins that target them to distinct subcellular locations for functional specificity. This review will summarize how PP1 regulates phosphorylation of some of the key cardiac proteins involved in Ca2+ handling and cardiac contraction, and the potential role of PP1 isoforms in controlling cardiac physiology and pathophysiology.
Collapse
|
5
|
Ravichandran VS, Patel HJ, Pagani FD, Westfall MV. Cardiac contractile dysfunction and protein kinase C-mediated myofilament phosphorylation in disease and aging. J Gen Physiol 2019; 151:1070-1080. [PMID: 31366607 PMCID: PMC6719401 DOI: 10.1085/jgp.201912353] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/25/2019] [Accepted: 06/19/2019] [Indexed: 01/10/2023] Open
Abstract
Increases in protein kinase C (PKC) are associated with diminished cardiac function, but the contribution of downstream myofilament phosphorylation is debated in human and animal models of heart failure. The current experiments evaluated PKC isoform expression, downstream cardiac troponin I (cTnI) S44 phosphorylation (p-S44), and contractile function in failing (F) human myocardium, and in rat models of cardiac dysfunction caused by pressure overload and aging. In F human myocardium, elevated PKCα expression and cTnI p-S44 developed before ventricular assist device implantation. Circulatory support partially reduced PKCα expression and cTnI p-S44 levels and improved cellular contractile function. Gene transfer of dominant negative PKCα (PKCαDN) into F human myocytes also improved contractile function and reduced cTnI p-S44. Heightened cTnI phosphorylation of the analogous residue accompanied reduced myocyte contractile function in a rat model of pressure overload and in aged Fischer 344 × Brown Norway F1 rats (≥26 mo). Together, these results indicate PKC-targeted cTnI p-S44 accompanies cardiac cellular dysfunction in human and animal models. Interfering with PKCα activity reduces downstream cTnI p-S44 levels and partially restores function, suggesting cTnI p-S44 may be a useful target to improve contractile function in the future.
Collapse
Affiliation(s)
- Vani S Ravichandran
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI
| | - Himanshu J Patel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI
| | - Francis D Pagani
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI
| | - Margaret V Westfall
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI
| |
Collapse
|
6
|
Biesiadecki BJ, Westfall MV. Troponin I modulation of cardiac performance: Plasticity in the survival switch. Arch Biochem Biophys 2019; 664:9-14. [PMID: 30684464 DOI: 10.1016/j.abb.2019.01.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/11/2018] [Accepted: 01/22/2019] [Indexed: 01/21/2023]
Abstract
Signaling complexes targeting the myofilament are essential in modulating cardiac performance. A central target of this signaling is cardiac troponin I (cTnI) phosphorylation. This review focuses on cTnI phosphorylation as a model for myofilament signaling, discussing key gaps and future directions towards understanding complex myofilament modulation of cardiac performance. Human heart cTnI is phosphorylated at 14 sites, giving rise to a complex modulatory network of varied functional responses. For example, while classical Ser23/24 phosphorylation mediates accelerated relaxation, protein kinase C phosphorylation of cTnI serves as a brake on contractile function. Additionally, the functional response of cTnI multi-site phosphorylation cannot necessarily be predicted from the response of individual sites alone. These complexities underscore the need for systematically evaluating single and multi-site phosphorylation on myofilament cellular and in vivo contractile function. Ultimately, a complete understanding of these multi-site responses requires work to establish site occupancy and dominance, kinase/phosphatase signaling balance, and the function of adaptive secondary phosphorylation. As cTnI phosphorylation is essential for modulating cardiac performance, future insight into the complex role of cTnI phosphorylation is important to establish sarcomere signaling in the healthy heart as well as identification of novel myofilament targets in the treatment of disease.
Collapse
Affiliation(s)
- Brandon J Biesiadecki
- Department of Physiology and Cell Biology, The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, 43210, USA.
| | - Margaret V Westfall
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, 48109, USA.
| |
Collapse
|
7
|
Secondary phosphorylation in myocytes expressing FLAG-tagged and non-tagged phospho-mimetic cardiac troponin I. Data Brief 2017; 15:562-566. [PMID: 29071293 PMCID: PMC5651495 DOI: 10.1016/j.dib.2017.09.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/26/2017] [Indexed: 11/22/2022] Open
Abstract
Secondary phosphorylation develops in myocytes expressing phospho-mimetic cardiac troponin I (cTnI) but it is not known whether multiple substitutions (e.g. cTnISDTD and cTnIS4D) cause preferential phosphorylation of the remaining endogenous or the phospho-mimetic cTnI in intact myocytes. Western analysis was performed to determine whether the FLAG/total cTnI ratios are similar for phosphorylated versus total cTnI in myocytes expressing phospho-mimetic cTnI with Asp(D) substitutions at S43/45 plus S23/24 (cTnIS4D) or T144 (cTnISDTD). Representative Western analysis of phosphorylated S23/24 (p-S23/24) and S150 (p-S150) are presented along with re-probes using an antibody which detects all cTnI (MAB1691 Ab). The level of p-S150 also is compared to results obtained using single S43D and/or S45D phospho-mimetic substitutions. These results are discussed in more detail in Lang et al. [1]
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Lang SE, Stevenson TK, Schatz TM, Biesiadecki BJ, Westfall MV. Functional communication between PKC-targeted cardiac troponin I phosphorylation sites. Arch Biochem Biophys 2017; 627:1-9. [PMID: 28587770 DOI: 10.1016/j.abb.2017.05.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/16/2017] [Accepted: 05/31/2017] [Indexed: 11/18/2022]
Abstract
Increased protein kinase C (PKC) activity is associated with heart failure, and can target multiple cardiac troponin I (cTnI) residues in myocytes, including S23/24, S43/45 and T144. In earlier studies, cTnI-S43D and/or -S45D augmented S23/24 and T144 phosphorylation, which suggested there is communication between clusters. This communication is now explored by evaluating the impact of phospho-mimetic cTnI S43/45D combined with S23/24D (cTnIS4D) or T144D (cTnISDTD). Gene transfer of epitope-tagged cTnIS4D and cTnISDTD into adult cardiac myocytes progressively replaced endogenous cTnI. Partial replacement with cTnISDTD or cTnIS4D accelerated the time to peak (TTP) shortening and time to 50% re-lengthening (TTR50%) on day 2, but peak shortening was only diminished by cTnIS4D. Extensive cTnIS4D replacement continued to accelerate TTP, and decrease shortening amplitude, while TTR50% returned to baseline levels on day 4. In contrast, cTnISDTD modestly reduced shortening amplitude and continued to accelerate myocyte TTP and TTR50%. These results indicate cTnIS43/45 communicates with S23/24 and T144, with S23/24 exacerbating and T144 attenuating the S43/45D-dependent functional deficit. In addition, more severe functional alterations in cTnIS4D myocytes were accompanied by higher levels of secondary phosphorylation compared to cTnISDTD. These results suggest that secondary phosphorylation helps to maintain steady-state contractile function during chronic cTnI phosphorylation at PKC sites.
Collapse
Affiliation(s)
- Sarah E Lang
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, United States; Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Tamara K Stevenson
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, United States
| | - Tabea M Schatz
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, United States
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, United States
| | - Margaret V Westfall
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, United States; Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, United States.
| |
Collapse
|
10
|
Pseudophosphorylation of cardiac myosin regulatory light chain: a promising new tool for treatment of cardiomyopathy. Biophys Rev 2017; 9:57-64. [PMID: 28510043 DOI: 10.1007/s12551-017-0248-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 01/05/2017] [Indexed: 12/21/2022] Open
Abstract
Many genetic mutations in sarcomeric proteins, including the cardiac myosin regulatory light chain (RLC) encoded by the MYL2 gene, have been implicated in familial cardiomyopathies. Yet, the molecular mechanisms by which these mutant proteins regulate cardiac muscle mechanics in health and disease remain poorly understood. Evidence has been accumulating that RLC phosphorylation has an influential role in striated muscle contraction and, in addition to the conventional modulation via Ca2+ binding to troponin C, it can regulate cardiac muscle function. In this review, we focus on RLC mutations that have been reported to cause cardiomyopathy phenotypes via compromised RLC phosphorylation and elaborate on pseudo-phosphorylation rescue mechanisms. This new methodology has been discussed as an emerging exploratory tool to understand the role of phosphorylation as well as a genetic modality to prevent/rescue cardiomyopathy phenotypes. Finally, we summarize structural effects post-phosphorylation, a phenomenon that leads to an ordered shift in the myosin S1 and RLC conformational equilibrium between two distinct states.
Collapse
|
11
|
Salhi HE, Hassel NC, Siddiqui JK, Brundage EA, Ziolo MT, Janssen PML, Davis JP, Biesiadecki BJ. Myofilament Calcium Sensitivity: Mechanistic Insight into TnI Ser-23/24 and Ser-150 Phosphorylation Integration. Front Physiol 2016; 7:567. [PMID: 28018230 PMCID: PMC5156683 DOI: 10.3389/fphys.2016.00567] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/08/2016] [Indexed: 11/14/2022] Open
Abstract
Troponin I (TnI) is a major regulator of cardiac muscle contraction and relaxation. During physiological and pathological stress, TnI is differentially phosphorylated at multiple residues through different signaling pathways to match cardiac function to demand. The combination of these TnI phosphorylations can exhibit an expected or unexpected functional integration, whereby the function of two phosphorylations are different than that predicted from the combined function of each individual phosphorylation alone. We have shown that TnI Ser-23/24 and Ser-150 phosphorylation exhibit functional integration and are simultaneously increased in response to cardiac stress. In the current study, we investigated the functional integration of TnI Ser-23/24 and Ser-150 to alter cardiac contraction. We hypothesized that Ser-23/24 and Ser-150 phosphorylation each utilize distinct molecular mechanisms to alter the TnI binding affinity within the thin filament. Mathematical modeling predicts that Ser-23/24 and Ser-150 phosphorylation affect different TnI affinities within the thin filament to distinctly alter the Ca2+-binding properties of troponin. Protein binding experiments validate this assertion by demonstrating pseudo-phosphorylated Ser-150 decreases the affinity of isolated TnI for actin, whereas Ser-23/24 pseudo-phosphorylation is not different from unphosphorylated. Thus, our data supports that TnI Ser-23/24 affects TnI-TnC binding, while Ser-150 phosphorylation alters TnI-actin binding. By measuring force development in troponin-exchanged skinned myocytes, we demonstrate that the Ca2+ sensitivity of force is directly related to the amount of phosphate present on TnI. Furthermore, we demonstrate that Ser-150 pseudo-phosphorylation blunts Ser-23/24-mediated decreased Ca2+-sensitive force development whether on the same or different TnI molecule. Therefore, TnI phosphorylations can integrate across troponins along the myofilament. These data demonstrate that TnI Ser-23/24 and Ser-150 phosphorylation regulates muscle contraction in part by modulating different TnI interactions in the thin filament and it is the combination of these differential mechanisms that provides understanding of their functional integration.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Brandon J. Biesiadecki
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State UniversityColumbus, OH, USA
| |
Collapse
|
12
|
Westfall MV. Contribution of Post-translational Phosphorylation to Sarcomere-Linked Cardiomyopathy Phenotypes. Front Physiol 2016; 7:407. [PMID: 27683560 PMCID: PMC5021686 DOI: 10.3389/fphys.2016.00407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 08/30/2016] [Indexed: 01/24/2023] Open
Abstract
Secondary shifts develop in post-translational phosphorylation of sarcomeric proteins in multiple animal models of inherited cardiomyopathy. These signaling alterations together with the primary mutation are predicted to contribute to the overall cardiac phenotype. As a result, identification and integration of post-translational myofilament signaling responses are identified as priorities for gaining insights into sarcomeric cardiomyopathies. However, significant questions remain about the nature and contribution of post-translational phosphorylation to structural remodeling and cardiac dysfunction in animal models and human patients. This perspective essay discusses specific goals for filling critical gaps about post-translational signaling in response to these inherited mutations, especially within sarcomeric proteins. The discussion focuses primarily on pre-clinical analysis of animal models and defines challenges and future directions in this field.
Collapse
|
13
|
Lang SE, Stevenson TK, Xu D, O'Connell R, Westfall MV. Functionally conservative substitutions at cardiac troponin I S43/45. Arch Biochem Biophys 2016; 601:42-7. [PMID: 26869200 PMCID: PMC4899172 DOI: 10.1016/j.abb.2016.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 01/13/2016] [Accepted: 02/01/2016] [Indexed: 12/22/2022]
Abstract
A phospho-null Ala substitution at protein kinase C (PKC)-targeted cardiac troponin I (cTnI) S43/45 reduces myocyte and cardiac contractile function. The goal of the current study was to test whether cTnIS43/45N is an alternative, functionally conservative substitution in cardiac myocytes. Partial and more extensive endogenous cTnI replacement was similar at 2 and 4 days after gene transfer, respectively, for epitope-tagged cTnI and cTnIS43/45N. This replacement did not significantly change thin filament stoichiometry. In functional studies, there were no significant changes in the amplitude and/or rates of contractile shortening and re-lengthening after this partial (2 days) and extensive (4 days) replacement with cTnIS43/45N. The cTnIS43/45N substitution also was not associated with adaptive changes in the myocyte Ca(2+) transient or in phosphorylation of the protein kinase A and C-targeted cTnIS23/24 site. These results provide evidence that cTnIS43/45N is a functionally conservative substitution, and may be appropriate for use as a phospho-null in rodent models designed for studies on PKC modulation of cardiac performance.
Collapse
Affiliation(s)
- Sarah E Lang
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Tamara K Stevenson
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dongyang Xu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ryan O'Connell
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Margaret V Westfall
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
| |
Collapse
|
14
|
Biesiadecki BJ, Ziolo MT. Should we treat heart failure with phosphatase inhibitors? Better to start at the end. J Mol Cell Cardiol 2015; 89:116-8. [PMID: 26497613 DOI: 10.1016/j.yjmcc.2015.10.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 10/16/2015] [Accepted: 10/19/2015] [Indexed: 01/21/2023]
Affiliation(s)
- Brandon J Biesiadecki
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
| | - Mark T Ziolo
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|