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Liu YB, Wang Q, Song YL, Song XM, Fan YC, Kong L, Zhang JS, Li S, Lv YJ, Li ZY, Dai JY, Qiu ZK. Abnormal phosphorylation / dephosphorylation and Ca 2+ dysfunction in heart failure. Heart Fail Rev 2024:10.1007/s10741-024-10395-w. [PMID: 38498262 DOI: 10.1007/s10741-024-10395-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2024] [Indexed: 03/20/2024]
Abstract
Heart failure (HF) can be caused by a variety of causes characterized by abnormal myocardial systole and diastole. Ca2+ current through the L-type calcium channel (LTCC) on the membrane is the initial trigger signal for a cardiac cycle. Declined systole and diastole in HF are associated with dysfunction of myocardial Ca2+ function. This disorder can be correlated with unbalanced levels of phosphorylation / dephosphorylation of LTCC, endoplasmic reticulum (ER), and myofilament. Kinase and phosphatase activity changes along with HF progress, resulting in phased changes in the degree of phosphorylation / dephosphorylation. It is important to realize the phosphorylation / dephosphorylation differences between a normal and a failing heart. This review focuses on phosphorylation / dephosphorylation changes in the progression of HF and summarizes the effects of phosphorylation / dephosphorylation of LTCC, ER function, and myofilament function in normal conditions and HF based on previous experiments and clinical research. Also, we summarize current therapeutic methods based on abnormal phosphorylation / dephosphorylation and clarify potential therapeutic directions.
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Affiliation(s)
- Yan-Bing Liu
- Interventional Medical Center, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, Shandong Province, China
- Medical College, Qingdao University, Qingdao, China
| | - Qian Wang
- Medical College, Qingdao University, Qingdao, China
| | - Yu-Ling Song
- Department of Pediatrics, Huantai County Hospital of Traditional Chinese Medicine, Zibo, China
| | | | - Yu-Chen Fan
- Medical College, Qingdao University, Qingdao, China
| | - Lin Kong
- Medical College, Qingdao University, Qingdao, China
| | | | - Sheng Li
- Medical College, Qingdao University, Qingdao, China
| | - Yi-Ju Lv
- Medical College, Qingdao University, Qingdao, China
| | - Ze-Yang Li
- Medical College, Qingdao University, Qingdao, China
| | - Jing-Yu Dai
- Department of Oncology, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, Shandong Province, China.
| | - Zhen-Kang Qiu
- Interventional Medical Center, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, Shandong Province, China.
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Janssens JV, Raaijmakers AJA, Weeks KL, Bell JR, Mellor KM, Curl CL, Delbridge LMD. The cardiomyocyte origins of diastolic dysfunction: cellular components of myocardial "stiffness". Am J Physiol Heart Circ Physiol 2024; 326:H584-H598. [PMID: 38180448 DOI: 10.1152/ajpheart.00334.2023] [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: 06/08/2023] [Revised: 12/07/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024]
Abstract
The impaired ability of the heart to relax and stretch to accommodate venous return is generally understood to represent a state of "diastolic dysfunction" and often described using the all-purpose noun "stiffness." Despite the now common qualitative usage of this term in fields of cardiac patho/physiology, the specific quantitative concept of stiffness as a molecular and biophysical entity with real practical interpretation in healthy and diseased hearts is sometimes obscure. The focus of this review is to characterize the concept of cardiomyocyte stiffness and to develop interpretation of "stiffness" attributes at the cellular and molecular levels. Here, we consider "stiffness"-related terminology interpretation and make links between cardiomyocyte stiffness and aspects of functional and structural cardiac performance. We discuss cross bridge-derived stiffness sources, considering the contributions of diastolic myofilament activation and impaired relaxation. This includes commentary relating to the role of cardiomyocyte Ca2+ flux and Ca2+ levels in diastole, the troponin-tropomyosin complex role as a Ca2+ effector in diastole, the myosin ADP dissociation rate as a modulator of cross bridge attachment and regulation of cross-bridge attachment by myosin binding protein C. We also discuss non-cross bridge-derived stiffness sources, including the titin sarcomeric spring protein, microtubule and intermediate filaments, and cytoskeletal extracellular matrix interactions. As the prevalence of conditions involving diastolic heart failure has escalated, a more sophisticated understanding of the molecular, cellular, and tissue determinants of cardiomyocyte stiffness offers potential to develop imaging and molecular intervention tools.
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Affiliation(s)
- Johannes V Janssens
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Antonia J A Raaijmakers
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Kate L Weeks
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
- Baker Department of Cardiometabolic Health, University of Melbourne, Melbourne, Victoria, Australia
- Department of Diabetes, Monash University, Parkville, Victoria, Australia
| | - James R Bell
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, Victoria, Australia
| | - Kimberley M Mellor
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Claire L Curl
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Lea M D Delbridge
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
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3
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Salyer LG, Salhi HE, Brundage EA, Shettigar V, Sturgill SL, Zanella H, Templeton B, Abay E, Emmer KM, Lowe J, Rafael-Fortney JA, Parinandi N, Foster DB, McKinsey TA, Woulfe KC, Ziolo MT, Biesiadecki BJ. Troponin I Tyrosine Phosphorylation Beneficially Accelerates Diastolic Function. Circ Res 2024; 134:33-45. [PMID: 38095088 PMCID: PMC10872382 DOI: 10.1161/circresaha.123.323132] [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: 05/23/2023] [Accepted: 11/28/2023] [Indexed: 01/06/2024]
Abstract
BACKGROUND A healthy heart is able to modify its function and increase relaxation through post-translational modifications of myofilament proteins. While there are known examples of serine/threonine kinases directly phosphorylating myofilament proteins to modify heart function, the roles of tyrosine (Y) phosphorylation to directly modify heart function have not been demonstrated. The myofilament protein TnI (troponin I) is the inhibitory subunit of the troponin complex and is a key regulator of cardiac contraction and relaxation. We previously demonstrated that TnI-Y26 phosphorylation decreases calcium-sensitive force development and accelerates calcium dissociation, suggesting a novel role for tyrosine kinase-mediated TnI-Y26 phosphorylation to regulate cardiac relaxation. Therefore, we hypothesize that increasing TnI-Y26 phosphorylation will increase cardiac relaxation in vivo and be beneficial during pathological diastolic dysfunction. METHODS The signaling pathway involved in TnI-Y26 phosphorylation was predicted in silico and validated by tyrosine kinase activation and inhibition in primary adult murine cardiomyocytes. To investigate how TnI-Y26 phosphorylation affects cardiac muscle, structure, and function in vivo, we developed a novel TnI-Y26 phosphorylation-mimetic mouse that was subjected to echocardiography, pressure-volume loop hemodynamics, and myofibril mechanical studies. TnI-Y26 phosphorylation-mimetic mice were further subjected to the nephrectomy/DOCA (deoxycorticosterone acetate) model of diastolic dysfunction to investigate the effects of increased TnI-Y26 phosphorylation in disease. RESULTS Src tyrosine kinase is sufficient to phosphorylate TnI-Y26 in cardiomyocytes. TnI-Y26 phosphorylation accelerates in vivo relaxation without detrimental structural or systolic impairment. In a mouse model of diastolic dysfunction, TnI-Y26 phosphorylation is beneficial and protects against the development of disease. CONCLUSIONS We have demonstrated that tyrosine kinase phosphorylation of TnI is a novel mechanism to directly and beneficially accelerate myocardial relaxation in vivo.
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Affiliation(s)
- Lorien G Salyer
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Hussam E Salhi
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Elizabeth A Brundage
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Vikram Shettigar
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Sarah L Sturgill
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Helena Zanella
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Benjamin Templeton
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Eaman Abay
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Kathryn M Emmer
- University Laboratory Animal Resources (K.M.E.), Ohio State University, Columbus
| | - Jeovanna Lowe
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Jill A Rafael-Fortney
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Narasimham Parinandi
- Division of Pulmonary, Critical Care and Sleep Medicine (N.P.), Ohio State University, Columbus
| | - D Brian Foster
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD (D.B.F.)
| | - Timothy A McKinsey
- Department of Medicine, Division of Cardiology (T.A.M., K.C.W.), University of Colorado Anschutz Medical Campus, Aurora
- Consortium for Fibrosis Research and Translation (T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Kathleen C Woulfe
- Department of Medicine, Division of Cardiology (T.A.M., K.C.W.), University of Colorado Anschutz Medical Campus, Aurora
| | - Mark T Ziolo
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute (L.G.S., H.E.S., E.A.B., V.S., S.L.S., H.Z., B.T., E.A., J.L., J.A.R.-F., M.T.Z., B.J.B.), Ohio State University, Columbus
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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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5
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Salhi HE, Shettigar V, Salyer L, Sturgill S, Brundage EA, Robinett J, Xu Z, Abay E, Lowe J, Janssen PML, Rafael-Fortney JA, Weisleder N, Ziolo MT, Biesiadecki BJ. The lack of Troponin I Ser-23/24 phosphorylation is detrimental to in vivo cardiac function and exacerbates cardiac disease. J Mol Cell Cardiol 2023; 176:84-96. [PMID: 36724829 PMCID: PMC10074981 DOI: 10.1016/j.yjmcc.2023.01.010] [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: 09/08/2022] [Revised: 01/11/2023] [Accepted: 01/24/2023] [Indexed: 01/30/2023]
Abstract
Troponin I (TnI) is a key regulator of cardiac contraction and relaxation with TnI Ser-23/24 phosphorylation serving as a myofilament mechanism to modulate cardiac function. Basal cardiac TnI Ser-23/24 phosphorylation is high such that both increased and decreased TnI phosphorylation may modulate cardiac function. While the effects of increasing TnI Ser-23/24 phosphorylation on heart function are well established, the effects of decreasing TnI Ser-23/24 phosphorylation are not clear. To understand the in vivo role of decreased TnI Ser-23/24 phosphorylation, mice expressing TnI with Ser-23/24 mutated to alanine (TnI S23/24A) that lack the ability to be phosphorylated at these residues were subjected to echocardiography and pressure-volume hemodynamic measurements in the absence or presence of physiological (pacing increasing heart rate or adrenergic stimulation) or pathological (transverse aortic constriction (TAC)) stress. In the absence of pathological stress, the lack of TnI Ser-23/24 phosphorylation impaired systolic and diastolic function. TnI S23/24A mice also had an impaired systolic and diastolic response upon stimulation increased heart rate and an impaired adrenergic response upon dobutamine infusion. Following pathological cardiac stress induced by TAC, TnI S23/24A mice had a greater increase in ventricular mass, worse diastolic function, and impaired systolic and diastolic function upon increasing heart rate. These findings demonstrate that mice lacking the ability to phosphorylate TnI at Ser-23/24 have impaired in vivo systolic and diastolic cardiac function, a blunted cardiac reserve and a worse response to pathological stress supporting decreased TnI Ser23/24 phosphorylation is a modulator of these processes in vivo.
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Affiliation(s)
- Hussam E Salhi
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Vikram Shettigar
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Lorien Salyer
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Sarah Sturgill
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Elizabeth A Brundage
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Joel Robinett
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Zhaobin Xu
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Eaman Abay
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Jeovanna Lowe
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Jill A Rafael-Fortney
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Noah Weisleder
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Mark T Ziolo
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America.
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6
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Robinett JC, Hanft LM, Biesiadecki B, McDonald KS. Molecular regulation of stretch activation. Am J Physiol Cell Physiol 2022; 323:C1728-C1739. [PMID: 36280392 PMCID: PMC9744651 DOI: 10.1152/ajpcell.00101.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 09/27/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022]
Abstract
Stretch activation is defined as a delayed increase in force after rapid stretches. Although there is considerable evidence for stretch activation in isolated cardiac myofibrillar preparations, few studies have measured mechanisms of stretch activation in mammalian skeletal muscle fibers. We measured stretch activation following rapid step stretches [∼1%-4% sarcomere length (SL)] during submaximal Ca2+ activations of rat permeabilized slow-twitch skeletal muscle fibers before and after protein kinase A (PKA), which phosphorylates slow myosin binding protein-C. PKA significantly increased stretch activation during low (∼25%) Ca2+ activation and accelerated rates of delayed force development (kef) during both low and half-maximal Ca2+ activation. Following the step stretches and subsequent force development, fibers were rapidly shortened to original sarcomere length, which often elicited a shortening-induced transient force overshoot. After PKA, step shortening-induced transient force overshoot increased ∼10-fold following an ∼4% SL shortening during low Ca2+ activation levels. kdf following step shortening also increased after PKA during low and half-maximal Ca2+ activations. We next investigated thin filament regulation of stretch activation. We tested the interplay between cardiac troponin I (cTnI) phosphorylation at the canonical PKA and novel tyrosine kinase sites on stretch activation. Native slow-skeletal Tn complexes were exchanged with recombinant human cTn complex with different human cTnI N-terminal pseudo-phosphorylation molecules: 1) nonphosphorylated wild type (WT), 2) the canonical S22/23D PKA sites, 3) the tyrosine kinase Y26E site, and 4) the combinatorial S22/23D + Y26E cTnI. All three pseudo-phosphorylated cTnIs elicited greater stretch activation than WT. Following stretch activation, a new, elevated stretch-induced steady-state force was reached with pseudo-phosphorylated cTnI. Combinatorial S22/23D + Y26E pseudo-phosphorylated cTnI increased kdf. These results suggest that slow-skeletal myosin binding protein-C (sMyBP-C) phosphorylation modulates stretch activation by a combination of cross-bridge recruitment and faster cycling kinetics, whereas cTnI phosphorylation regulates stretch activation by both redundant and synergistic mechanisms; and, taken together, these sarcomere phosphoproteins offer precision targets for enhanced contractility.
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Affiliation(s)
- Joel C Robinett
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, Missouri
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Laurin M Hanft
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, Missouri
| | - Brandon Biesiadecki
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Kerry S McDonald
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, Missouri
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7
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Xu M, Bermea KC, Ayati M, Kim HB, Yang X, Medina A, Fu Z, Heravi A, Zhang X, Na CH, Everett AD, Gabrielson K, Foster DB, Paolocci N, Murphy AM, Ramirez-Correa GA. Alteration in tyrosine phosphorylation of cardiac proteome and EGFR pathway contribute to hypertrophic cardiomyopathy. Commun Biol 2022; 5:1251. [PMID: 36380187 PMCID: PMC9666710 DOI: 10.1038/s42003-022-04021-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 09/22/2022] [Indexed: 11/16/2022] Open
Abstract
Alterations of serine/threonine phosphorylation of the cardiac proteome are a hallmark of heart failure. However, the contribution of tyrosine phosphorylation (pTyr) to the pathogenesis of cardiac hypertrophy remains unclear. We use global mapping to discover and quantify site-specific pTyr in two cardiac hypertrophic mouse models, i.e., cardiac overexpression of ErbB2 (TgErbB2) and α myosin heavy chain R403Q (R403Q-αMyHC Tg), compared to control hearts. From this, there are significant phosphoproteomic alterations in TgErbB2 mice in right ventricular cardiomyopathy, hypertrophic cardiomyopathy (HCM), and dilated cardiomyopathy (DCM) pathways. On the other hand, R403Q-αMyHC Tg mice indicated that the EGFR1 pathway is central for cardiac hypertrophy, along with angiopoietin, ErbB, growth hormone, and chemokine signaling pathways activation. Surprisingly, most myofilament proteins have downregulation of pTyr rather than upregulation. Kinase-substrate enrichment analysis (KSEA) shows a marked downregulation of MAPK pathway activity downstream of k-Ras in TgErbB2 mice and activation of EGFR, focal adhesion, PDGFR, and actin cytoskeleton pathways. In vivo ErbB2 inhibition by AG-825 decreases cardiomyocyte disarray. Serine/threonine and tyrosine phosphoproteome confirm the above-described pathways and the effectiveness of AG-825 Treatment. Thus, altered pTyr may play a regulatory role in cardiac hypertrophic models.
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Affiliation(s)
- Mingguo Xu
- grid.21107.350000 0001 2171 9311Department of Pediatrics/Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD USA ,Department of Pediatrics, The Third People’s Hospital of Longgang District, Shenzhen, 518115 China
| | - Kevin C. Bermea
- grid.21107.350000 0001 2171 9311Department of Pediatrics/Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Marzieh Ayati
- grid.449717.80000 0004 5374 269XDeparment of Computer Science/College of Engineering and Computer Science, University of Texas Rio Grande Valley School of Medicine, Edinburgh, Texas USA
| | - Han Byeol Kim
- grid.21107.350000 0001 2171 9311Department of Neurology/Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Xiaomei Yang
- grid.27255.370000 0004 1761 1174Department of Anesthesiology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Ji’nan, China
| | - Andres Medina
- Department of Molecular Science/UT Health Rio Grande Valley, McAllen, TX USA
| | - Zongming Fu
- grid.21107.350000 0001 2171 9311Department of Pediatrics/Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Amir Heravi
- grid.21107.350000 0001 2171 9311Department of Pediatrics/Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Xinyu Zhang
- grid.27255.370000 0004 1761 1174Department of Cardiology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Ji’nan, China
| | - Chan Hyun Na
- grid.21107.350000 0001 2171 9311Department of Neurology/Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD USA ,grid.21107.350000 0001 2171 9311Department of Biological Chemistry/McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Allen D. Everett
- grid.21107.350000 0001 2171 9311Department of Pediatrics/Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Kathleen Gabrielson
- grid.21107.350000 0001 2171 9311Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - D. Brian Foster
- grid.21107.350000 0001 2171 9311Department of Medicine/Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Nazareno Paolocci
- grid.21107.350000 0001 2171 9311Department of Medicine/Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD USA ,grid.5608.b0000 0004 1757 3470Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Anne M. Murphy
- grid.21107.350000 0001 2171 9311Department of Pediatrics/Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Genaro A. Ramirez-Correa
- grid.21107.350000 0001 2171 9311Department of Pediatrics/Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD USA ,Department of Molecular Science/UT Health Rio Grande Valley, McAllen, TX USA
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Truncation of the N-terminus of cardiac troponin I initiates adaptive remodeling of the myocardial proteosome via phosphorylation of mechano-sensitive signaling pathways. Mol Cell Biochem 2022; 477:1803-1815. [PMID: 35316461 DOI: 10.1007/s11010-022-04414-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 03/10/2022] [Indexed: 10/18/2022]
Abstract
The cardiac isoform of troponin I has a unique N-terminal extension (~ 1-30 amino acids), which contributes to the modulation of cardiac contraction and relaxation. Hearts of various species including humans produce a truncated variant of cardiac troponin I (cTnI-ND) deleting the first ~ 30 amino acids as an adaption in pathophysiological conditions. In this study, we investigated the impact of cTnI-ND chronic expression in transgenic mouse hearts compared to wildtype (WT) controls (biological n = 8 in each group). We aimed to determine the global phosphorylation effects of cTnI-ND on the cardiac proteome, thereby determining the signaling pathways that have an impact on cardiac function. The samples were digested and isobarically labeled and equally mixed for relative quantification via nanoLC-MS/MS. The peptides were then enriched for phospho-peptides and bioinformatic analysis was done with Ingenuity Pathway Analysis (IPA). We found approximately 77% replacement of the endogenous intact cTnI with cTnI-ND in the transgenic mouse hearts with 1674 phospho-proteins and 2971 non-modified proteins. There were 73 significantly altered phospho-proteins; bioinformatic analysis identified the top canonical pathways as associated with integrin, protein kinase A, RhoA, and actin cytoskeleton signaling. Among the 73 phospho-proteins compared to controls cTnI-ND hearts demonstrated a significant decrease in paxillin and YAP1, which are known to play a role in cell mechano-sensing pathways. Our data indicate that cTnI-ND modifications in the sarcomere are sufficient to initiate changes in the phospho-signaling profile that may underly the chronic-adaptive response associated with cTnI cleavage in response to stressors by modifying mechano-sensitive signaling pathways.
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9
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Quantitative Analysis of the Cardiac Phosphoproteome in Response to Acute β-Adrenergic Receptor Stimulation In Vivo. Int J Mol Sci 2021; 22:ijms222212584. [PMID: 34830474 PMCID: PMC8618155 DOI: 10.3390/ijms222212584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 11/17/2022] Open
Abstract
β-adrenergic receptor (β-AR) stimulation represents a major mechanism of modulating cardiac output. In spite of its fundamental importance, its molecular basis on the level of cell signalling has not been characterised in detail yet. We employed mass spectrometry-based proteome and phosphoproteome analysis using SuperSILAC (spike-in stable isotope labelling by amino acids in cell culture) standardization to generate a comprehensive map of acute phosphoproteome changes in mice upon administration of isoprenaline (ISO), a synthetic β-AR agonist that targets both β1-AR and β2-AR subtypes. Our data describe 8597 quantitated phosphopeptides corresponding to 10,164 known and novel phospho-events from 2975 proteins. In total, 197 of these phospho-events showed significantly altered phosphorylation, indicating an intricate signalling network activated in response to β-AR stimulation. In addition, we unexpectedly detected significant cardiac expression and ISO-induced fragmentation of junctophilin-1, a junctophilin isoform hitherto only thought to be expressed in skeletal muscle. Data are available via ProteomeXchange with identifier PXD025569.
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10
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Katraki-Pavlou S, Kastana P, Bousis D, Ntenekou D, Varela A, Davos CH, Nikou S, Papadaki E, Tsigkas G, Athanasiadis E, Herradon G, Mikelis CM, Beis D, Papadimitriou E. Protein tyrosine phosphatase receptor zeta 1 deletion triggers defective heart morphogenesis in mice and zebrafish. Am J Physiol Heart Circ Physiol 2021; 322:H8-H24. [PMID: 34767486 PMCID: PMC8754060 DOI: 10.1152/ajpheart.00400.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Protein tyrosine phosphatase receptor-ζ1 (PTPRZ1) is a transmembrane
tyrosine phosphatase receptor highly expressed in embryonic stem cells. In the
present work, gene expression analyses of Ptprz1−/− and Ptprz1+/+ mice endothelial cells and hearts pointed to
an unidentified role of PTPRZ1 in heart development through the regulation of
heart-specific transcription factor genes. Echocardiography analysis in mice
identified that both systolic and diastolic functions are affected in Ptprz1−/− compared with Ptprz1+/+ hearts, based on a dilated left
ventricular (LV) cavity, decreased ejection fraction and fraction shortening,
and increased angiogenesis in Ptprz1−/−
hearts, with no signs of cardiac hypertrophy. A zebrafish ptprz1−/− knockout was also generated and exhibited
misregulated expression of developmental cardiac markers, bradycardia, and
defective heart morphogenesis characterized by enlarged ventricles and defected
contractility. A selective PTPRZ1 tyrosine phosphatase inhibitor affected
zebrafish heart development and function in a way like what is observed in the
ptprz1−/− zebrafish. The same
inhibitor had no effect in the function of the adult zebrafish heart, suggesting
that PTPRZ1 is not important for the adult heart function, in line with data
from the human cell atlas showing very low to negligible PTPRZ1 expression in
the adult human heart. However, in line with the animal models, Ptprz1 was expressed in many different cell types in
the human fetal heart, such as valvar, fibroblast-like, cardiomyocytes, and
endothelial cells. Collectively, these data suggest that PTPRZ1 regulates
cardiac morphogenesis in a way that subsequently affects heart function and
warrant further studies for the involvement of PTPRZ1 in idiopathic congenital
cardiac pathologies. NEW & NOTEWORTHY Protein tyrosine phosphatase receptor
ζ1 (PTPRZ1) is expressed in fetal but not adult heart and seems
to affect heart development. In both mouse and zebrafish animal models, loss of
PTPRZ1 results in dilated left ventricle cavity, decreased ejection fraction,
and fraction shortening, with no signs of cardiac hypertrophy. PTPRZ1 also seems
to be involved in atrioventricular canal specification, outflow tract
morphogenesis, and heart angiogenesis. These results suggest that PTPRZ1 plays a
role in heart development and support the hypothesis that it may be involved in
congenital cardiac pathologies.
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Affiliation(s)
- Stamatiki Katraki-Pavlou
- Zebrafish Disease Models Lab, Center for Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation Academy of Athens, Greece.,Laboratory of Molecular Pharmacology, Department of Pharmacy, School of Health Sciences, University of Patras, Greece
| | - Pinelopi Kastana
- Laboratory of Molecular Pharmacology, Department of Pharmacy, School of Health Sciences, University of Patras, Greece
| | - Dimitris Bousis
- Laboratory of Molecular Pharmacology, Department of Pharmacy, School of Health Sciences, University of Patras, Greece
| | - Despoina Ntenekou
- Laboratory of Molecular Pharmacology, Department of Pharmacy, School of Health Sciences, University of Patras, Greece
| | - Aimilia Varela
- Cardiovascular Research Laboratory, Biomedical Research Foundation, Academy of Athens, Greece
| | - Constantinos H Davos
- Cardiovascular Research Laboratory, Biomedical Research Foundation, Academy of Athens, Greece
| | - Sophia Nikou
- Department of Anatomy-Histology-Embryology, Medical School, University of Patras, Greece
| | - Eleni Papadaki
- Department of Anatomy-Histology-Embryology, Medical School, University of Patras, Greece
| | - Grigorios Tsigkas
- Department of Cardiology, Patras University Hospital, Rio, Patras, Greece
| | | | - Gonzalo Herradon
- Department of Pharmaceutical and Health Sciences, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
| | - Constantinos M Mikelis
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, United States
| | - Dimitris Beis
- Zebrafish Disease Models Lab, Center for Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation Academy of Athens, Greece
| | - Evangelia Papadimitriou
- Laboratory of Molecular Pharmacology, Department of Pharmacy, School of Health Sciences, University of Patras, Greece
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11
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Mahmud Z, Dhami PS, Rans C, Liu PB, Hwang PM. Dilated Cardiomyopathy Mutations and Phosphorylation disrupt the Active Orientation of Cardiac Troponin C. J Mol Biol 2021; 433:167010. [PMID: 33901537 DOI: 10.1016/j.jmb.2021.167010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/07/2021] [Accepted: 04/20/2021] [Indexed: 11/28/2022]
Abstract
Cardiac troponin (cTn) is made up of three subunits, cTnC, cTnI, and cTnT. The regulatory N-terminal domain of cTnC (cNTnC) controls cardiac muscle contraction in a calcium-dependent manner. We show that calcium-saturated cNTnC can adopt two different orientations, with the "active" orientation consistent with the 2020 cryo-EM structure of the activated cardiac thin filament by Yamada et al. Using solution NMR 15N R2 relaxation analysis, we demonstrate that the two domains of cTnC tumble independently (average R2 10 s-1), being connected by a flexible linker. However, upon addition of cTnI1-77, the complex tumbles as a rigid unit (R2 30 s-1). cTnI phosphomimetic mutants S22D/S23D, S41D/S43D and dilated cardiomyopathy- (DCM-)associated mutations cTnI K35Q, cTnC D75Y, and cTnC G159D destabilize the active orientation of cNTnC, with intermediate 15N R2 rates (R2 17-23 s-1). The active orientation of cNTnC is stabilized by the flexible tails of cTnI, cTnI1-37 and cTnI135-209. Surprisingly, when cTnC is incorporated into complexes lacking these tails (cTnC-cTnI38-134, cTnC-cTnT223-288, or cTnC-cTnI38-134-cTnT223-288), the cNTnC domain is still immobilized, revealing a new interaction between cNTnC and the IT-arm that stabilizes a "dormant" orientation. We propose that the calcium sensitivity of the cardiac troponin complex is regulated by an equilibrium between active and dormant orientations, which can be shifted through post-translational modifications or DCM-associated mutations.
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Affiliation(s)
- Zabed Mahmud
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Prabhpaul S Dhami
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Caleb Rans
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Philip B Liu
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Peter M Hwang
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada; Department of Medicine, University of Alberta, Edmonton, AB T6G 2R3, Canada.
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12
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Warren CM, Halas M, Feng HZ, Wolska BM, Jin JP, Solaro RJ. NH 2-Terminal Cleavage of Cardiac Troponin I Signals Adaptive Response to Cardiac Stressors. JOURNAL OF CELLULAR SIGNALING 2021; 2:162-171. [PMID: 34541579 PMCID: PMC8444995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/29/2022]
Abstract
Cardiac sarcomeres express a variant of troponin I (cTnI) that contains a unique N-terminal extension of ~30 amino acids with regulatory phosphorylation sites. The extension is important in the control of myofilament response to Ca2+, which contributes to the neuro-humoral regulation of the dynamics of cardiac contraction and relaxation. Hearts of various species including humans express a stress-induced truncated variant of cardiac troponin I (cTnI-ND) missing the first ~30 amino acids and functionally mimicking the phosphorylated state of cTnI. Studies have demonstrated that upregulation of cTnI-ND potentially represents a homeostatic mechanism as well as an adaptive response in pathophysiology including ischemia/reperfusion injury, beta adrenergic maladaptive activation, and aging. We present evidence showing that cTnI-ND can modify the trigger for hypertrophic cardiomyopathy (HCM) by reducing the Ca2+ sensitivity of myofilaments from hearts with an E180G mutation in α-tropomyosin. Induction of this truncation may represent a therapeutic approach to modifying Ca2+-responses in hearts with hypercontractility or heat failure with preserved ejection fraction.
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Affiliation(s)
- Chad M. Warren
- Department of Physiology & Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago, USA
| | - Monika Halas
- Department of Physiology & Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago, USA
| | - Han-Zhong Feng
- Department of Physiology & Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago, USA
| | - Beata M. Wolska
- Department of Physiology & Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago, USA,Division of Cardiology, Center for Cardiovascular Research, University of Illinois at Chicago, USA
| | - Jian-Ping Jin
- Department of Physiology & Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago, USA
| | - R. John Solaro
- Department of Physiology & Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago, USA,Correspondence should be addressed to R. John Solaro;
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13
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Wadthaisong M, Wattanapermpool J, de Tombe PP, Bupha-Intr T. Suppression of myofilament cross-bridge kinetic in the heart of orchidectomized rats. Life Sci 2020; 261:118342. [PMID: 32853655 DOI: 10.1016/j.lfs.2020.118342] [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: 06/12/2020] [Revised: 08/11/2020] [Accepted: 08/21/2020] [Indexed: 11/30/2022]
Abstract
AIMS The increased incidence of heart failure with reduced ejection fraction in men compared with women suggests that male sex hormones significantly impact myocardial contractile activation. This study aims to examine associations among molecular alterations, cellular modulations and in vivo cardiac contractile function upon deprivation of testicular hormones. MAIN METHODS Myocardial structure and functions were compared among sham-operated control and twelve-week orchidectomized (ORX) male rats with and without testosterone supplementation. KEY FINDINGS Echocardiography and pressure-volume relationships demonstrated a decreased left ventricular ejection fraction compared with sham-operated controls. The percentage of contractility reduction was generally similar to the decrease in tension development detected in both right ventricular trabeculae and skinned isolated left ventricular cardiomyocytes of ORX rats. Reductions in tension cost and the rate constant of tension redevelopment (ktr) in ORX samples suggested a decrease in the rate of cross-bridge formation, reflecting a reduced number of cross-bridges. Slow cross-bridge detachment in ORX rat hearts could result from a shift of myosin heavy chain isoforms towards a slower ATPase activity β-isoform and reductions in the phosphorylation levels of cardiac troponin I and myosin binding protein-C. All the changes in the ORX rat heart, including ejection fractions and myofilament protein expression and phosphorylation, were completed attenuated by a physiological dose of testosterone. SIGNIFICANCE Testosterone plays a critical role in regulating the mechanical and contractile dynamics of the heart. Deprivation of male sex hormones cause the loss of normal preserved cardiac contractile function leading to a high risk of severe cardiomyopathy progression.
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Affiliation(s)
- Munthana Wadthaisong
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand; Department of Cell and Molecular Physiology, Loyola University Chicago Health Sciences Division, Maywood, IL, United States of America
| | | | - Pieter P de Tombe
- Department of Cell and Molecular Physiology, Loyola University Chicago Health Sciences Division, Maywood, IL, United States of America; Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Tepmanas Bupha-Intr
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand.
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14
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Blair CA, Brundage EA, Thompson KL, Stromberg A, Guglin M, Biesiadecki BJ, Campbell KS. Heart Failure in Humans Reduces Contractile Force in Myocardium From Both Ventricles. JACC Basic Transl Sci 2020; 5:786-798. [PMID: 32875169 PMCID: PMC7452203 DOI: 10.1016/j.jacbts.2020.05.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 05/18/2020] [Accepted: 05/18/2020] [Indexed: 01/01/2023]
Abstract
Contractile assays were performed using multicellular preparations isolated from the left and right ventricles of organ donors and patients with heart failure. Heart failure reduced maximum force and power by approximately 30% in the myocardium from both ventricles. Heart failure increased the Ca2+ sensitivity of contraction, but the effect was bigger in right ventricular tissue than in left ventricular samples. The changes in Ca2+ sensitivity may reflect ventricle-specific post-translational modifications to sarcomeric proteins.
This study measured how heart failure affects the contractile properties of the human myocardium from the left and right ventricles. The data showed that maximum force and maximum power were reduced by approximately 30% in multicellular preparations from both ventricles, possibly because of ventricular remodeling (e.g., cellular disarray and/or excess fibrosis). Heart failure increased the calcium (Ca2+) sensitivity of contraction in both ventricles, but the effect was bigger in right ventricular samples. The changes in Ca2+ sensitivity were associated with ventricle-specific changes in the phosphorylation of troponin I, which indicated that adrenergic stimulation might induce different effects in the left and right ventricles.
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Key Words
- Ca2+ sensitivity
- Ca2+, calcium
- Fact, maximum Ca2+-activated force
- Fpas, passive force
- LV, left ventricle
- MyBP-C, myosin binding protein-C
- PKA, protein kinase A
- Pmax, maximum power output
- RLC, regulatory light chain
- RV, right ventricle
- TnI, troponin I
- Vmax, maximum shortening velocity
- heart failure
- human myocardium
- ktr, rate of force recovery
- myofilament proteins
- nH, Hill coefficient
- ventricular function
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Affiliation(s)
- Cheavar A Blair
- Department of Physiology, University of Kentucky, Lexington, Kentucky
| | - Elizabeth A Brundage
- Department of Physiology and Cell Biology and The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | | | - Arnold Stromberg
- Department of Statistics, University of Kentucky, Lexington, Kentucky
| | - Maya Guglin
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology and The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, Kentucky.,Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky
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15
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Lin YH, Schmidt W, Fritz KS, Jeong MY, Cammarato A, Foster DB, Biesiadecki BJ, McKinsey TA, Woulfe KC. Site-specific acetyl-mimetic modification of cardiac troponin I modulates myofilament relaxation and calcium sensitivity. J Mol Cell Cardiol 2020; 139:135-147. [PMID: 31981571 DOI: 10.1016/j.yjmcc.2020.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Cardiac troponin I (cTnI) is an essential physiological and pathological regulator of cardiac relaxation. Significant to this regulation, the post-translational modification of cTnI through phosphorylation functions as a key mechanism to accelerate myofibril relaxation. Similar to phosphorylation, post-translational modification by acetylation alters amino acid charge and protein function. Recent studies have demonstrated that the acetylation of cardiac myofibril proteins accelerates relaxation and that cTnI is acetylated in the heart. These findings highlight the potential significance of myofilament acetylation; however, it is not known if site-specific acetylation of cTnI can lead to changes in myofilament, myofibril, and/or cellular mechanics. The objective of this study was to determine the effects of mimicking acetylation at a single site of cTnI (lysine-132; K132) on myofilament, myofibril, and cellular mechanics and elucidate its influence on molecular function. METHODS To determine if pseudo-acetylation of cTnI at 132 modulates thin filament regulation of the acto-myosin interaction, we reconstituted thin filaments containing WT or K132Q (to mimic acetylation) cTnI and assessed in vitro motility. To test if mimicking acetylation at K132 alters cellular relaxation, adult rat ventricular cardiomyocytes were infected with adenoviral constructs expressing either cTnI K132Q or K132 replaced with arginine (K132R; to prevent acetylation) and cell shortening and isolated myofibril mechanics were measured. Finally, to confirm that changes in cell shortening and myofibril mechanics were directly due to pseudo-acetylation of cTnI at K132, we exchanged troponin containing WT or K132Q cTnI into isolated myofibrils and measured myofibril mechanical properties. RESULTS Reconstituted thin filaments containing K132Q cTnI exhibited decreased calcium sensitivity compared to thin filaments reconstituted with WT cTnI. Cardiomyocytes expressing K132Q cTnI had faster relengthening and myofibrils isolated from these cells had faster relaxation along with decreased calcium sensitivity compared to cardiomyocytes expressing WT or K132R cTnI. Myofibrils exchanged with K132Q cTnI ex vivo demonstrated faster relaxation and decreased calcium sensitivity. CONCLUSIONS Our results indicate for the first time that mimicking acetylation of a specific cTnI lysine accelerates myofilament, myofibril, and myocyte relaxation. This work underscores the importance of understanding how acetylation of specific sarcomeric proteins affects cardiac homeostasis and disease and suggests that modulation of myofilament lysine acetylation may represent a novel therapeutic target to alter cardiac relaxation.
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Affiliation(s)
- Ying H Lin
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - William Schmidt
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Kristofer S Fritz
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Mark Y Jeong
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - D Brian Foster
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology, The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States of America
| | - Timothy A McKinsey
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America; Consortium for Fibrosis Research & Translation, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America.
| | - Kathleen C Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America.
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16
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Ding Y, Lyons SA, Scott GR, Gillis TE. Characterizing the influence of chronic hypobaric hypoxia on diaphragmatic myofilament contractile function and phosphorylation in high-altitude deer mice and low-altitude white-footed mice. J Comp Physiol B 2019; 189:489-499. [PMID: 31278612 DOI: 10.1007/s00360-019-01224-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 06/06/2019] [Accepted: 06/24/2019] [Indexed: 11/27/2022]
Abstract
Deer mice, Peromyscusmaniculatus, live at high altitudes where limited O2 represents a challenge to maintaining oxygen delivery to tissues. Previous work has demonstrated that hypoxia acclimation of deer mice and low altitude white-footed mice (P. leucopus) increases the force generating capacity of the diaphragm. The mechanism behind this improved contractile function is not known. Within myocytes, the myofilament plays a critical role in setting the rate and level of force production, and its ability to generate force can change in response to changes in physiological conditions. In the current study, we examined how chronic hypobaric hypoxia exposure of deer mice and white-footed mice influences the Ca2+ activation of force generation by skinned diaphragmatic myofilaments, and the phosphorylation of myofilament proteins. Results demonstrate that myofilament force production, and the Ca2+ sensitivity of force generation, were not impacted by acclimation to hypobaric hypoxia, and did not differ between preparations from the two species. The cooperativity of the force-pCa relationship, and the maximal rate of force generation were also the same in the preparations from both species, and not impacted by acclimation. Finally, the relative phosphorylation of TnT, and MLC was lower in deer mice than white-footed mice, but was not affected by acclimation. These results indicate that species differences in diaphragm function, and the increase in force production with hypoxia acclimation, are not due to differences, or changes, in myofilament function. However, it appears that diaphragmatic myofilament function in these species is not affected by chronic hypobaric hypoxia exposure.
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Affiliation(s)
- Y Ding
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G-2W1, Canada
| | - S A Lyons
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - G R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Todd E Gillis
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G-2W1, Canada.
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17
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Lehman SJ, Tal-Grinspan L, Lynn ML, Strom J, Benitez GE, Anderson ME, Tardiff JC. Chronic Calmodulin-Kinase II Activation Drives Disease Progression in Mutation-Specific Hypertrophic Cardiomyopathy. Circulation 2019; 139:1517-1529. [PMID: 30586744 PMCID: PMC6461395 DOI: 10.1161/circulationaha.118.034549] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND Although the genetic causes of hypertrophic cardiomyopathy (HCM) are widely recognized, considerable lag in the development of targeted therapeutics has limited interventions to symptom palliation. This is in part attributable to an incomplete understanding of how point mutations trigger pathogenic remodeling. As a further complication, similar mutations within sarcomeric genes can result in differential disease severity, highlighting the need to understand the mechanism of progression at the molecular level. One pathway commonly linked to HCM progression is calcium homeostasis dysregulation, though how specific mutations disrupt calcium homeostasis remains unclear. METHODS To evaluate the effects of early intervention in calcium homeostasis, we used 2 mouse models of sarcomeric HCM (cardiac troponin T R92L and R92W) with differential myocellular calcium dysregulation and disease presentation. Two modes of intervention were tested: inhibition of the autoactivated calcium-dependent kinase (calmodulin kinase II [CaMKII]) via the AC3I peptide and diltiazem, an L-type calcium channel antagonist. Two-dimensional echocardiography was used to determine cardiac function and left ventricular remodeling, and atrial remodeling was monitored via atrial mass. Sarcoplasmic reticulum Ca2+ATPase activity was measured as an index of myocellular calcium handling and coupled to its regulation via the phosphorylation status of phospholamban. RESULTS We measured an increase in phosphorylation of CaMKII in R92W animals by 6 months of age, indicating increased autonomous activity of the kinase in these animals. Inhibition of CaMKII led to recovery of diastolic function and partially blunted atrial remodeling in R92W mice. This improved function was coupled to increased sarcoplasmic reticulum Ca2+ATPase activity in the R92W animals despite reduction of CaMKII activation, likely indicating improvement in myocellular calcium handling. In contrast, inhibition of CaMKII in R92L animals led to worsened myocellular calcium handling, remodeling, and function. Diltiazem-HCl arrested diastolic dysfunction progression in R92W animals only, with no improvement in cardiac remodeling in either genotype. CONCLUSIONS We propose a highly specific, mutation-dependent role of activated CaMKII in HCM progression and a precise therapeutic target for clinical management of HCM in selected cohorts. Moreover, the mutation-specific response elicited with diltiazem highlights the necessity to understand mutation-dependent progression at a molecular level to precisely intervene in disease progression.
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Affiliation(s)
- Sarah J. Lehman
- Department of Physiological Sciences, University of Arizona, Tucson, Arizona 85724, USA
| | - Lauren Tal-Grinspan
- Department of Medicine, Columbia University Medical Center, New York, New York 10032, USA
| | - Melissa L. Lynn
- Department of Medicine, University of Arizona, Tucson, Arizona, 85724, USA
| | - Joshua Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona 85724, USA
| | - Grace E. Benitez
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, 85724, USA
| | - Mark E. Anderson
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21287, USA
| | - Jil C. Tardiff
- Department of Medicine, University of Arizona, Tucson, Arizona, 85724, USA
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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.
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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.
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19
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Abstract
This article focuses on three "bins" that comprise sets of biophysical derangements elicited by cardiomyopathy-associated mutations in the myofilament. Current therapies focus on symptom palliation and do not address the disease at its core. We and others have proposed that a more nuanced classification could lead to direct interventions based on early dysregulation changing the trajectory of disease progression in the preclinical cohort. Continued research is necessary to address the complexity of cardiomyopathic progression and develop efficacious therapeutics.
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Affiliation(s)
- Melissa L Lynn
- Department of Medicine, University of Arizona, Room 317, 1656 East Mabel Street, Tucson, AZ 85724, USA
| | - Sarah J Lehman
- Department of Physiological Sciences, University of Arizona, Room 317, 1656 East Mabel Street, Tucson, AZ 85724, USA
| | - Jil C Tardiff
- Department of Medicine, University of Arizona, Room 312, 1656 East Mabel Street, Tucson, AZ 85724, USA.
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Ryba DM, Li J, Cowan CL, Russell B, Wolska BM, Solaro RJ. Long-Term Biased β-Arrestin Signaling Improves Cardiac Structure and Function in Dilated Cardiomyopathy. Circulation 2017; 135:1056-1070. [PMID: 28104714 DOI: 10.1161/circulationaha.116.024482] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 01/12/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Biased agonism of the angiotensin II receptor is known to promote cardiac contractility. Our laboratory indicated that these effects may be attributable to changes at the level of the myofilaments. However, these signaling mechanisms remain unknown. Because a common finding in dilated cardiomyopathy is a reduction in the myofilament-Ca2+ response, we hypothesized that β-arrestin signaling would increase myofilament-Ca2+ responsiveness in a model of familial dilated cardiomyopathy and improve cardiac function and morphology. METHODS We treated a dilated cardiomyopathy-linked mouse model expressing a mutant tropomyosin (Tm-E54K) for 3 months with either TRV120067, a β-arrestin 2-biased ligand of the angiotensin II receptor, or losartan, an angiotensin II receptor blocker. At the end of the treatment protocol, we assessed cardiac function using echocardiography, the myofilament-Ca2+ response of detergent-extracted fiber bundles, and used proteomic approaches to understand changes in posttranslational modifications of proteins that may explain functional changes. We also assessed signaling pathways altered in vivo and by using isolated myocytes. RESULTS TRV120067- treated Tm-E54K mice showed improved cardiac structure and function, whereas losartan-treated mice had no improvement. Myofilaments of TRV120067-treated Tm-E54K mice had significantly improved myofilament-Ca2+ responsiveness, which was depressed in untreated Tm-E54K mice. We attributed these changes to increased MLC2v and MYPT1/2 phosphorylation seen only in TRV120067-treated mice. We found that the functional changes were attributable to an activation of ERK1/2-RSK3 signaling, mediated through β-arrestin, which may have a novel role in increasing MLC2v phosphorylation through a previously unrecognized interaction of β-arrestin localized to the sarcomere. CONCLUSIONS Long-term β-arrestin 2-biased agonism of the angiotensin II receptor may be a viable approach to the treatment of dilated cardiomyopathy by not only preventing maladaptive signaling, but also improving cardiac function by altering the myofilament-Ca2+ response via β-arrestin signaling pathways.
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Affiliation(s)
- David M Ryba
- From Department of Physiology and Biophysics and Center for Cardiovascular Research, University of Illinois at Chicago (D.M.R., J.L., B.R., B.M.W., R.J.S.); Department of Medicine, Division of Cardiology, University of Illinois at Chicago (B.M.W.); and Trevena, Inc. King of Prussia, PA (B.M.W.)
| | - Jieli Li
- From Department of Physiology and Biophysics and Center for Cardiovascular Research, University of Illinois at Chicago (D.M.R., J.L., B.R., B.M.W., R.J.S.); Department of Medicine, Division of Cardiology, University of Illinois at Chicago (B.M.W.); and Trevena, Inc. King of Prussia, PA (B.M.W.)
| | - Conrad L Cowan
- From Department of Physiology and Biophysics and Center for Cardiovascular Research, University of Illinois at Chicago (D.M.R., J.L., B.R., B.M.W., R.J.S.); Department of Medicine, Division of Cardiology, University of Illinois at Chicago (B.M.W.); and Trevena, Inc. King of Prussia, PA (B.M.W.)
| | - Brenda Russell
- From Department of Physiology and Biophysics and Center for Cardiovascular Research, University of Illinois at Chicago (D.M.R., J.L., B.R., B.M.W., R.J.S.); Department of Medicine, Division of Cardiology, University of Illinois at Chicago (B.M.W.); and Trevena, Inc. King of Prussia, PA (B.M.W.)
| | - Beata M Wolska
- From Department of Physiology and Biophysics and Center for Cardiovascular Research, University of Illinois at Chicago (D.M.R., J.L., B.R., B.M.W., R.J.S.); Department of Medicine, Division of Cardiology, University of Illinois at Chicago (B.M.W.); and Trevena, Inc. King of Prussia, PA (B.M.W.)
| | - R John Solaro
- From Department of Physiology and Biophysics and Center for Cardiovascular Research, University of Illinois at Chicago (D.M.R., J.L., B.R., B.M.W., R.J.S.); Department of Medicine, Division of Cardiology, University of Illinois at Chicago (B.M.W.); and Trevena, Inc. King of Prussia, PA (B.M.W.).
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21
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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] [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.
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Affiliation(s)
- Hussam E Salhi
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State University Columbus, OH, USA
| | - Nathan C Hassel
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State University Columbus, OH, USA
| | - Jalal K Siddiqui
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State University Columbus, OH, USA
| | - Elizabeth A Brundage
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State University Columbus, OH, USA
| | - Mark T Ziolo
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State University Columbus, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State University Columbus, OH, USA
| | - Jonathan P Davis
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State University Columbus, OH, USA
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, Ohio State University Columbus, OH, USA
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22
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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.
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23
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Cheng Y, Regnier M. Cardiac troponin structure-function and the influence of hypertrophic cardiomyopathy associated mutations on modulation of contractility. Arch Biochem Biophys 2016; 601:11-21. [PMID: 26851561 PMCID: PMC4899195 DOI: 10.1016/j.abb.2016.02.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/30/2016] [Accepted: 02/02/2016] [Indexed: 11/29/2022]
Abstract
Cardiac troponin (cTn) acts as a pivotal regulator of muscle contraction and relaxation and is composed of three distinct subunits (cTnC: a highly conserved Ca(2+) binding subunit, cTnI: an actomyosin ATPase inhibitory subunit, and cTnT: a tropomyosin binding subunit). In this mini-review, we briefly summarize the structure-function relationship of cTn and its subunits, its modulation by PKA-mediated phosphorylation of cTnI, and what is known about how these properties are altered by hypertrophic cardiomyopathy (HCM) associated mutations of cTnI. This includes recent work using computational modeling approaches to understand the atomic-based structural level basis of disease-associated mutations. We propose a viewpoint that it is alteration of cTnC-cTnI interaction (rather than the Ca(2+) binding properties of cTn) per se that disrupt the ability of PKA-mediated phosphorylation at cTnI Ser-23/24 to alter contraction and relaxation in at least some HCM-associated mutations. The combination of state of the art biophysical approaches can provide new insight on the structure-function mechanisms of contractile dysfunction resulting cTnI mutations and exciting new avenues for the diagnosis, prevention, and even treatment of heart diseases.
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Affiliation(s)
- Yuanhua Cheng
- University of Washington, Department of Bioengineering, Seattle, WA, USA
| | - Michael Regnier
- University of Washington, Department of Bioengineering, Seattle, WA, USA.
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24
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Gross SM, Lehman SL. Functional phosphorylation sites in cardiac myofilament proteins are evolutionarily conserved in skeletal myofilament proteins. Physiol Genomics 2016; 48:377-87. [PMID: 26993364 DOI: 10.1152/physiolgenomics.00112.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 03/11/2016] [Indexed: 01/14/2023] Open
Abstract
Protein phosphorylation plays an important role in regulating cardiac contractile function, but phosphorylation is not thought to play a regulatory role in skeletal muscle. To examine how myofilament phosphorylation arose in the human heart, we analyzed the amino acid sequences of 25 cardiac phosphorylation sites in animals ranging from fruit flies to humans. These analyses indicated that of the 25 human phosphorylation sites examined, 11 have been conserved across vertebrates and four have been sporadically present in vertebrates. Furthermore, all 11 of the cardiac sites found across vertebrates were present in skeletal muscle isoforms, along with three sites that were sporadically present. Based on the conservation of amino acid sequences between cardiac and skeletal contractile proteins, we tested for phosphorylation in mammalian skeletal muscle using several biochemical techniques and found evidence that multiple myofilament proteins were phosphorylated. Several of these phosphorylation sites were validated using mass spectrometry, including one site that is present in slow- and fast-twitch troponin I (TnI), but was lost in cardiac TnI. Thus, several myofilament phosphorylation sites present in the human heart likely arose in invertebrate muscle, have been evolutionarily conserved in skeletal muscle, and potentially have functional effects in both skeletal and cardiac muscle.
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Affiliation(s)
- Sean M Gross
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California; and Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - Steven L Lehman
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California; and
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25
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Designing proteins to combat disease: Cardiac troponin C as an example. Arch Biochem Biophys 2016; 601:4-10. [PMID: 26901433 DOI: 10.1016/j.abb.2016.02.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 02/04/2016] [Indexed: 01/18/2023]
Abstract
Throughout history, muscle research has led to numerous scientific breakthroughs that have brought insight to a more general understanding of all biological processes. Potentially one of the most influential discoveries was the role of the second messenger calcium and its myriad of handling and sensing systems that mechanistically control muscle contraction. In this review we will briefly discuss the significance of calcium as a universal second messenger along with some of the most common calcium binding motifs in proteins, focusing on the EF-hand. We will also describe some of our approaches to rationally design calcium binding proteins to palliate, or potentially even cure cardiovascular disease. Considering not all failing hearts have the same etiology, genetic background and co-morbidities, personalized therapies will need to be developed. We predict designer proteins will open doors for unprecedented personalized, and potentially, even generalized medicines as gene therapy or protein delivery techniques come to fruition.
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26
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Sheng JJ, Jin JP. TNNI1, TNNI2 and TNNI3: Evolution, regulation, and protein structure-function relationships. Gene 2015; 576:385-94. [PMID: 26526134 DOI: 10.1016/j.gene.2015.10.052] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 09/21/2015] [Accepted: 10/20/2015] [Indexed: 12/11/2022]
Abstract
Troponin I (TnI) is the inhibitory subunit of the troponin complex in the sarcomeric thin filament of striated muscle and plays a central role in the calcium regulation of contraction and relaxation. Vertebrate TnI has evolved into three isoforms encoded by three homologous genes: TNNI1 for slow skeletal muscle TnI, TNNI2 for fast skeletal muscle TnI and TNNI3 for cardiac TnI, which are expressed under muscle type-specific and developmental regulations. To summarize the current knowledge on the TnI isoform genes and products, this review focuses on the evolution, gene regulation, posttranslational modifications, and structure-function relationship of TnI isoform proteins. Their physiological and medical significances are also discussed.
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Affiliation(s)
- Juan-Juan Sheng
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Jian-Ping Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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27
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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
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28
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Zhang M, Martin JL, Kumar M, Khairallah RJ, de Tombe PP. Rapid large-scale purification of myofilament proteins using a cleavable His6-tag. Am J Physiol Heart Circ Physiol 2015; 309:H1509-15. [PMID: 26386113 DOI: 10.1152/ajpheart.00598.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/15/2015] [Indexed: 11/22/2022]
Abstract
With the advent of high-throughput DNA sequencing, the number of identified cardiomyopathy-causing mutations has increased tremendously. As the majority of these mutations affect myofilament proteins, there is a need to understand their functional consequence on contraction. Permeabilized myofilament preparations coupled with protein exchange protocols are a common method for examining into contractile mechanics. However, producing large quantities of myofilament proteins can be time consuming and requires different approaches for each protein of interest. In the present study, we describe a unified automated method to produce troponin C, troponin T, and troponin I as well as myosin light chain 2 fused to a His6-tag followed by a tobacco etch virus (TEV) protease site. TEV protease has the advantage of a relaxed P1' cleavage site specificity, allowing for no residues left after proteolysis and preservation of the native sequence of the protein of interest. After expression in Esherichia coli, cells were lysed by sonication in imidazole-containing buffer. The His6-tagged protein was then purified using a HisTrap nickel metal affinity column, and the His6-tag was removed by His6-TEV protease digestion for 4 h at 30°C. The protease was then removed using a HisTrap column, and complex assembly was performed via column-assisted sequential desalting. This mostly automated method allows for the purification of protein in 1 day and can be adapted to most soluble proteins. It has the advantage of greatly increasing yield while reducing the time and cost of purification. Therefore, production and purification of mutant proteins can be accelerated and functional data collected in a faster, less expensive manner.
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Affiliation(s)
- Mengjie Zhang
- Department of Cell and Molecular Physiology, Loyola University, Chicago, Illinois
| | - Jody L Martin
- Department of Cell and Molecular Physiology, Loyola University, Chicago, Illinois
| | - Mohit Kumar
- Department of Cell and Molecular Physiology, Loyola University, Chicago, Illinois
| | - Ramzi J Khairallah
- Department of Cell and Molecular Physiology, Loyola University, Chicago, Illinois
| | - Pieter P de Tombe
- Department of Cell and Molecular Physiology, Loyola University, Chicago, Illinois
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