1
|
Saad NS, Mashali MA, Repas SJ, Janssen PML. Altering Calcium Sensitivity in Heart Failure: A Crossroads of Disease Etiology and Therapeutic Innovation. Int J Mol Sci 2023; 24:17577. [PMID: 38139404 PMCID: PMC10744146 DOI: 10.3390/ijms242417577] [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: 11/20/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023] Open
Abstract
Heart failure (HF) presents a significant clinical challenge, with current treatments mainly easing symptoms without stopping disease progression. The targeting of calcium (Ca2+) regulation is emerging as a key area for innovative HF treatments that could significantly alter disease outcomes and enhance cardiac function. In this review, we aim to explore the implications of altered Ca2+ sensitivity, a key determinant of cardiac muscle force, in HF, including its roles during systole and diastole and its association with different HF types-HF with preserved and reduced ejection fraction (HFpEF and HFrEF, respectively). We further highlight the role of the two rate constants kon (Ca2+ binding to Troponin C) and koff (its dissociation) to fully comprehend how changes in Ca2+ sensitivity impact heart function. Additionally, we examine how increased Ca2+ sensitivity, while boosting systolic function, also presents diastolic risks, potentially leading to arrhythmias and sudden cardiac death. This suggests that strategies aimed at moderating myofilament Ca2+ sensitivity could revolutionize anti-arrhythmic approaches, reshaping the HF treatment landscape. In conclusion, we emphasize the need for precision in therapeutic approaches targeting Ca2+ sensitivity and call for comprehensive research into the complex interactions between Ca2+ regulation, myofilament sensitivity, and their clinical manifestations in HF.
Collapse
Affiliation(s)
- Nancy S. Saad
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Helwan University, Cairo 11795, Egypt
| | - Mohammed A. Mashali
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Department of Surgery, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22514, Egypt
| | - Steven J. Repas
- Department of Emergency Medicine, Wright State University Boonshoft School of Medicine, Dayton, OH 45324, USA;
| | - Paul M. L. Janssen
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
2
|
Loescher CM, Freundt JK, Unger A, Hessel AL, Kühn M, Koser F, Linke WA. Titin governs myocardial passive stiffness with major support from microtubules and actin and the extracellular matrix. NATURE CARDIOVASCULAR RESEARCH 2023; 2:991-1002. [PMID: 39196092 PMCID: PMC11358001 DOI: 10.1038/s44161-023-00348-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 09/19/2023] [Indexed: 08/29/2024]
Abstract
Myocardial passive stiffness is crucial for the heart's pump function and is determined by mechanical elements, including the extracellular matrix and cytoskeletal filaments; however, their individual contributions are controversially discussed and difficult to quantify. In this study, we targeted the cytoskeletal filaments in a mouse model, which enables the specific, acute and complete cleavage of the sarcomeric titin springs. We show in vitro that each cytoskeletal filament's stiffness contribution varies depending on whether the elastic or the viscous forces are considered and on strain level. Titin governs myocardial elastic forces, with the largest contribution provided at both low and high strain. Viscous force contributions are more uniformly distributed among the microtubules, titin and actin. The extracellular matrix contributes at high strain. The remaining forces after total target element disruption are likely derived from desmin filaments. Our findings answer longstanding questions about cardiac mechanical architecture and allow better targeting of passive myocardial stiffness in heart failure.
Collapse
Affiliation(s)
| | - Johanna K Freundt
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Andreas Unger
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Anthony L Hessel
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Michel Kühn
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Franziska Koser
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Wolfgang A Linke
- Institute of Physiology II, University of Muenster, Muenster, Germany.
| |
Collapse
|
3
|
Bayne EF, Rossler KJ, Gregorich ZR, Aballo TJ, Roberts DS, Chapman EA, Guo W, Palecek SP, Ralphe JC, Kamp TJ, Ge Y. Top-down proteomics of myosin light chain isoforms define chamber-specific expression in the human heart. J Mol Cell Cardiol 2023; 181:89-97. [PMID: 37327991 PMCID: PMC10528938 DOI: 10.1016/j.yjmcc.2023.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 05/27/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023]
Abstract
Myosin functions as the "molecular motor" of the sarcomere and generates the contractile force necessary for cardiac muscle contraction. Myosin light chains 1 and 2 (MLC-1 and -2) play important functional roles in regulating the structure of the hexameric myosin molecule. Each of these light chains has an 'atrial' and 'ventricular' isoform, so called because they are believed to exhibit chamber-restricted expression in the heart. However, recently the chamber-specific expression of MLC isoforms in the human heart has been questioned. Herein, we analyzed the expression of MLC-1 and -2 atrial and ventricular isoforms in each of the four cardiac chambers in adult non-failing donor hearts using top-down mass spectrometry (MS)-based proteomics. Strikingly, we detected an isoform thought to be ventricular, MLC-2v (gene: MYL2), in the atria and confirmed the protein sequence using tandem MS (MS/MS). For the first time, a putative deamidation post-translation modification (PTM) located on MLC-2v in atrial tissue was localized to amino acid N13. MLC-1v (MYL3) and MLC-2a (MYL7) were the only MLC isoforms exhibiting chamber-restricted expression patterns across all donor hearts. Importantly, our results unambiguously show that MLC-1v, not MLC-2v, is ventricle-specific in adult human hearts. Moreover, we found elevated MLC-2 phosphorylation in male hearts compared to female hearts across each cardiac chamber. Overall, top-down proteomics allowed an unbiased analysis of MLC isoform expression throughout the human heart, uncovering previously unexpected isoform expression patterns and PTMs.
Collapse
Affiliation(s)
- Elizabeth F Bayne
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kalina J Rossler
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Zachery R Gregorich
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Timothy J Aballo
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - David S Roberts
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Emily A Chapman
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Wei Guo
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sean P Palecek
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - J Carter Ralphe
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Timothy J Kamp
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ying Ge
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705, USA; Human Proteomics Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA.
| |
Collapse
|
4
|
Lynn ML, Jimenez J, Castillo RL, Klass MM, Vasquez C, Baldo A, Gibson C, Murphy AM, Tardiff JC. The HCM - Linked Mutation Arg92Leu in TNNT2 Allosterically Alters the cTnC - cTnI Interface and Disrupts the PKA-mediated Regulation of Myofilament Relaxation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.18.549569. [PMID: 37503299 PMCID: PMC10370115 DOI: 10.1101/2023.07.18.549569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Background Impaired left ventricular relaxation, high filling pressures, and dysregulation of Ca 2+ homeostasis are common findings contributing to diastolic dysfunction in hypertrophic cardiomyopathy (HCM). Studies have shown that impaired relaxation is an early observation in the sarcomere-gene-positive preclinical HCM cohort which suggests potential involvement of myofilament regulators of relaxation. Yet, a molecular level understanding of mechanism(s) at the level of the myofilament is lacking. We hypothesized that mutation-specific, allosterically mediated, changes to the cardiac troponin C-cardiac troponin I (cTnC-cTnI) interface can account for the development of early-onset diastolic dysfunction via decreased PKA accessibility to cTnI. Methods HCM mutations R92L-cTnT (Arg92Leu) and Δ160E-cTnT (Glu160 deletion) were studied in vivo , in vitro, and in silico via 2D echocardiography, western blotting, ex vivo hemodynamics, stopped-flow kinetics, time resolved fluorescence resonance energy transfer (TR-FRET), and molecular dynamics simulations. Results The HCM-causative mutations R92L-cTnT and Δ160E-cTnT result in different time-of-onset of diastolic dysfunction. R92L-cTnT demonstrated early-onset diastolic dysfunction accompanied by a localized decrease in phosphorylation of cTnI. Constitutive phosphorylation of cTnI (cTnI-D 23 D 24 ) was sufficient to recover diastolic function to Non-Tg levels only for R92L-cTnT. Mutation-specific changes in Ca 2+ dissociation rates associated with R92L-cTnT reconstituted with cTnI-D 23 D 24 led us to investigate potential involvement of structural changes in the cTnC-cTnI interface as an explanation for these observations. We probed the interface via TR-FRET revealing a repositioning of the N-terminus of cTnI, closer to cTnC, and concomitant decreases in distance distributions at sites flanking the PKA consensus sequence. Implementing TR-FRET distances as constraints into our atomistic model identified additional electrostatic interactions at the consensus sequence. Conclusion These data indicate that the early diastolic dysfunction observed in a subset of HCM is likely attributable to structural changes at the cTnC-cTnI interface that impair accessibility of PKA thereby blunting β-adrenergic responsiveness and identifying a potential molecular target for therapeutic intervention.
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Sun B, Kekenes-Huskey PM. Myofilament-associated proteins with intrinsic disorder (MAPIDs) and their resolution by computational modeling. Q Rev Biophys 2023; 56:e2. [PMID: 36628457 PMCID: PMC11070111 DOI: 10.1017/s003358352300001x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The cardiac sarcomere is a cellular structure in the heart that enables muscle cells to contract. Dozens of proteins belong to the cardiac sarcomere, which work in tandem to generate force and adapt to demands on cardiac output. Intriguingly, the majority of these proteins have significant intrinsic disorder that contributes to their functions, yet the biophysics of these intrinsically disordered regions (IDRs) have been characterized in limited detail. In this review, we first enumerate these myofilament-associated proteins with intrinsic disorder (MAPIDs) and recent biophysical studies to characterize their IDRs. We secondly summarize the biophysics governing IDR properties and the state-of-the-art in computational tools toward MAPID identification and characterization of their conformation ensembles. We conclude with an overview of future computational approaches toward broadening the understanding of intrinsic disorder in the cardiac sarcomere.
Collapse
Affiliation(s)
- Bin Sun
- Research Center for Pharmacoinformatics (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), Department of Medicinal Chemistry and Natural Medicine Chemistry, College of Pharmacy, Harbin Medical University, Harbin 150081, China
| | | |
Collapse
|
7
|
Huang AW, Janssen PML. The Case for, and Challenges of, Human Cardiac Tissue in Advancing Phosphoprotein Research. Front Physiol 2022; 13:853511. [PMID: 35399265 PMCID: PMC8984461 DOI: 10.3389/fphys.2022.853511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 02/09/2022] [Indexed: 11/18/2022] Open
Abstract
Cardiovascular disease (CVD) and stroke affect over 92 million Americans and account for nearly 1 out of 3 deaths in the US. The use of animal models in cardiovascular research has led to considerable advances in treatment and in our understanding of the pathophysiology of many CVDs. Still, animals may not fully recapitulate human disease states; species differences have long been postulated to be one of the main reasons for a failure of translation between animals and humans in drug discovery and development. Indeed, it has become increasingly clear over the past few decades that to answer certain biomedical questions, like the physiological mechanisms that go awry in many human CVDs, animal tissues may not always be the best option to use. While human cardiac tissue has long been used for laboratory research, published findings often contradict each other, leading to difficulties in interpretation. Current difficulties in utilizing human cardiac tissue include differences in acquisition time, varying tissue procurement protocols, and the struggle to define a human “control” sample. With the tremendous emphasis on translational research that continues to grow, research studies using human tissues are becoming more common. This mini review will discuss advantages, disadvantages, and considerations of using human cardiac tissue in the study of CVDs, paying specific attention to the study of phosphoproteins.
Collapse
|
8
|
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
|
9
|
Hanft LM, Fitzsimons DP, Hacker TA, Moss RL, McDonald KS. Cardiac MyBP-C phosphorylation regulates the Frank-Starling relationship in murine hearts. J Gen Physiol 2021; 153:e202012770. [PMID: 33646280 PMCID: PMC7927661 DOI: 10.1085/jgp.202012770] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 01/04/2021] [Accepted: 01/26/2021] [Indexed: 01/08/2023] Open
Abstract
The Frank-Starling relationship establishes that elevated end-diastolic volume progressively increases ventricular pressure and stroke volume in healthy hearts. The relationship is modulated by a number of physiological inputs and is often depressed in human heart failure. Emerging evidence suggests that cardiac myosin-binding protein-C (cMyBP-C) contributes to the Frank-Starling relationship. We measured contractile properties at multiple levels of structural organization to determine the role of cMyBP-C and its phosphorylation in regulating (1) the sarcomere length dependence of power in cardiac myofilaments and (2) the Frank-Starling relationship in vivo. We compared transgenic mice expressing wild-type cMyBP-C on the null background, which have ∼50% phosphorylated cMyBP-C (Controls), to transgenic mice lacking cMyBP-C (KO) and to mice expressing cMyBP-C that have serine-273, -282, and -302 mutated to aspartate (cMyBP-C t3SD) or alanine (cMyBP-C t3SA) on the null background to mimic either constitutive PKA phosphorylation or nonphosphorylated cMyBP-C, respectively. We observed a continuum of length dependence of power output in myocyte preparations. Sarcomere length dependence of power progressively increased with a rank ordering of cMyBP-C KO = cMyBP-C t3SA < Control < cMyBP-C t3SD. Length dependence of myofilament power translated, at least in part, to hearts, whereby Frank-Starling relationships were steepest in cMyBP-C t3SD mice. The results support the hypothesis that cMyBP-C and its phosphorylation state tune sarcomere length dependence of myofibrillar power, and these regulatory processes translate across spatial levels of myocardial organization to control beat-to-beat ventricular performance.
Collapse
Affiliation(s)
- Laurin M. Hanft
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
| | - Daniel P. Fitzsimons
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
| | - Timothy A. Hacker
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Richard L. Moss
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
| | - Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
| |
Collapse
|
10
|
Cool AM, Lindert S. Computational Methods Elucidate Consequences of Mutations and Post-translational Modifications on Troponin I Effective Concentration to Troponin C. J Phys Chem B 2021; 125:7388-7396. [PMID: 34213339 DOI: 10.1021/acs.jpcb.1c03844] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ca2+ binding to cardiac troponin C (cTnC) causes a conformational shift that exposes a hydrophobic patch (cTnCHP) for binding of the cTnI switch peptide (cTnISP), ultimately resulting in contraction of the heart. The inhibitory peptide (cTnIIP), attached at the N-terminal end of the cTnISP, serves as a tether for the cTnISP to the rest of the troponin complex. Due to this tethered nature, the cTnISP remains within proximity of the hydrophobic patch region, resulting in the cTnCHP experiencing an elevated "effective concentration" of the cTnISP. Mutations to the cTnIIP region have been hypothesized to cause disease by affecting the ability of the cTnISP to "find" the hydrophobic patch, resulting in alterations to the heart's ability to contract normally. We tested this hypothesis using molecular dynamics (MD) simulations of the troponin complex using a model that contained all three subunits of troponin: C, I, and T. We developed methods that allowed us to quantitatively measure the effective concentration of the cTnISP from the simulations. A significant reduction in the cTnISP effective concentration was observed when the cTnIIP was removed from the system, showcasing the importance of a tethered cTnISP. Through accelerated MD methods, we proposed the minimum effective concentration of a tethered cTnISP to be approximately 21 mM. Modification of the cTnIIP via PKC-mediated phosphorylation of T143 was shown to significantly increase the estimated effective concentration of cTnISP, help the cTnISP find the cTnCHP more effectively, and maintain the relative shape of the cTnIIP when compared to the native model. All of these data indicate that pT143 may be able to help promote binding of cTnISP to the cTnCHP. We then tested six mutations within the cTnIIP region that are known cTnC Ca2+-sensitizing mutations and have been linked with cardiomyopathy. We did not observe a significant reduction in the effective concentration upon the introduction of these mutations; however, we did observe increased variability in the flexibility and dynamics of the cTnIIP region when compared to native. Our observations led us to hypothesize that the mechanism by which these cardiomyopathic mutations affect Ca2+ sensitivity is by altering the off rate of cTnISP from the hydrophobic patch.
Collapse
Affiliation(s)
- Austin M Cool
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| |
Collapse
|
11
|
Travers JG, Wennersten SA, Peña B, Bagchi RA, Smith HE, Hirsch RA, Vanderlinden LA, Lin YH, Dobrinskikh E, Demos-Davies KM, Cavasin MA, Mestroni L, Steinkühler C, Lin CY, Houser SR, Woulfe KC, Lam MPY, McKinsey TA. HDAC Inhibition Reverses Preexisting Diastolic Dysfunction and Blocks Covert Extracellular Matrix Remodeling. Circulation 2021; 143:1874-1890. [PMID: 33682427 DOI: 10.1161/circulationaha.120.046462] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Diastolic dysfunction (DD) is associated with the development of heart failure and contributes to the pathogenesis of other cardiac maladies, including atrial fibrillation. Inhibition of histone deacetylases (HDACs) has been shown to prevent DD by enhancing myofibril relaxation. We addressed the therapeutic potential of HDAC inhibition in a model of established DD with preserved ejection fraction. METHODS Four weeks after uninephrectomy and implantation with deoxycorticosterone acetate pellets, when DD was clearly evident, 1 cohort of mice was administered the clinical-stage HDAC inhibitor ITF2357/Givinostat. Echocardiography, blood pressure measurements, and end point invasive hemodynamic analyses were performed. Myofibril mechanics and intact cardiomyocyte relaxation were assessed ex vivo. Cardiac fibrosis was evaluated by picrosirius red staining and second harmonic generation microscopy of left ventricle (LV) sections, RNA sequencing of LV mRNA, mass spectrometry-based evaluation of decellularized LV biopsies, and atomic force microscopy determination of LV stiffness. Mechanistic studies were performed with primary rat and human cardiac fibroblasts. RESULTS HDAC inhibition normalized DD without lowering blood pressure in this model of systemic hypertension. In contrast to previous models, myofibril relaxation was unimpaired in uninephrectomy/deoxycorticosterone acetate mice. Furthermore, cardiac fibrosis was not evident in any mouse cohort on the basis of picrosirius red staining or second harmonic generation microscopy. However, mass spectrometry revealed induction in the expression of >100 extracellular matrix proteins in LVs of uninephrectomy/deoxycorticosterone acetate mice, which correlated with profound tissue stiffening based on atomic force microscopy. ITF2357/Givinostat treatment blocked extracellular matrix expansion and LV stiffening. The HDAC inhibitor was subsequently shown to suppress cardiac fibroblast activation, at least in part, by blunting recruitment of the profibrotic chromatin reader protein BRD4 (bromodomain-containing protein 4) to key gene regulatory elements. CONCLUSIONS These findings demonstrate the potential of HDAC inhibition as a therapeutic intervention to reverse existing DD and establish blockade of extracellular matrix remodeling as a second mechanism by which HDAC inhibitors improve ventricular filling. Our data reveal the existence of pathophysiologically relevant covert or hidden cardiac fibrosis that is below the limit of detection of histochemical stains such as picrosirius red, highlighting the need to evaluate fibrosis of the heart using diverse methodologies.
Collapse
Affiliation(s)
- Joshua G Travers
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Sara A Wennersten
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Brisa Peña
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Rushita A Bagchi
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Harrison E Smith
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX (H.E.S., R.A.H., C.Y.L.).,Department of Biostatistics and Informatics (H.E.S., L.A.V.), Colorado School of Public Health, Aurora
| | - Rachel A Hirsch
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX (H.E.S., R.A.H., C.Y.L.)
| | - Lauren A Vanderlinden
- Department of Biostatistics and Informatics (H.E.S., L.A.V.), Colorado School of Public Health, Aurora
| | - Ying-Hsi Lin
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Evgenia Dobrinskikh
- Department of Medicine, Division of Pulmonary Sciences & Critical Care (E.D.), University of Colorado Anschutz Medical Campus, Aurora
| | - Kimberly M Demos-Davies
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Maria A Cavasin
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Luisa Mestroni
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | | | - Charles Y Lin
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX (H.E.S., R.A.H., C.Y.L.).,now with Kronos Bio, Cambridge, MA (C.Y.L.)
| | - Steven R Houser
- Cardiovascular Research Center (S.R.H.), Lewis Katz School of Medicine, Temple University, Philadelphia, PA
| | - Kathleen C Woulfe
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Maggie P Y Lam
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| | - Timothy A McKinsey
- Department of Medicine, Division of Cardiology (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., K.M.D.-D., M.A.C., L.M., K.C.W., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora.,Consortium for Fibrosis Research & Translation (J.G.T., S.A.W., B.P., R.A.B., Y.-H.L., M.A.C., M.P.Y.L., T.A.M.), University of Colorado Anschutz Medical Campus, Aurora
| |
Collapse
|
12
|
Pappritz K, Klein O, Dong F, Hamdani N, Kovacs A, O'Flynn L, Elliman S, O'Brien T, Tschöpe C, Van Linthout S. MALDI-IMS as a Tool to Determine the Myocardial Response to Syndecan-2-Selected Mesenchymal Stromal Cell Application in an Experimental Model of Diabetic Cardiomyopathy. Proteomics Clin Appl 2021; 15:e2000050. [PMID: 33068073 DOI: 10.1002/prca.202000050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/12/2020] [Indexed: 01/08/2023]
Abstract
PURPOSE Mesenchymal stromal cells (MSC) are an attractive tool for treatment of diabetic cardiomyopathy. Syndecan-2/CD362 has been identified as a functional marker for MSC isolation. Imaging mass spectrometry (IMS) allows for the characterization of therapeutic responses in the left ventricle. This study aims to investigate whether IMS can assess the therapeutic effect of CD362+ -selected MSC on early onset experimental diabetic cardiomyopathy. EXPERIMENTAL DESIGN 1 × 106 wild type (WT), CD362- , or CD362+ MSC are intravenously injected into db/db mice. Four weeks later, mice are hemodynamically characterized and subsequently sacrificed for IMS combined with bottom-up mass spectrometry, and isoform and phosphorylation analyses of cardiac titin. RESULTS Overall alterations of the cardiac proteome signatures, especially titin, are observed in db/db compared to control mice. Interestingly, only CD362+ MSC can overcome the reduced titin intensity distribution and shifts the isoform ratio toward the more compliant N2BA form. In contrast, WT and CD362- MSCs improve all-titin phosphorylation and protein kinase G activity, which is reflected in an improvement in diastolic performance. CONCLUSIONS AND CLINICAL RELEVANCE IMS enables the characterization of differences in titin intensity distribution following MSC application. However, further analysis of titin phosphorylation is needed to allow for the assessment of the therapeutic efficacy of MSC.
Collapse
Affiliation(s)
- Kathleen Pappritz
- Berlin-Brandenburg Center for Regenerative Therapies and Berlin Institute of Health Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, Campus Virchow Klinikum (CVK), Berlin, 13353 and 10178, Germany
- German Center for Cardiovascular Research (DZHK), Partner site Berlin, Berlin, 13347, Germany
| | - Oliver Klein
- Berlin-Brandenburg Center for Regenerative Therapies and Berlin Institute of Health Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, Campus Virchow Klinikum (CVK), Berlin, 13353 and 10178, Germany
- German Center for Cardiovascular Research (DZHK), Partner site Berlin, Berlin, 13347, Germany
| | - Fengquan Dong
- Berlin-Brandenburg Center for Regenerative Therapies and Berlin Institute of Health Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, Campus Virchow Klinikum (CVK), Berlin, 13353 and 10178, Germany
| | - Nazha Hamdani
- Department of Physiology, Institute of Physiology, Ruhr University Bochum, Bochum, 44780, Germany
| | - Arpad Kovacs
- Department of Physiology, Institute of Physiology, Ruhr University Bochum, Bochum, 44780, Germany
| | - Lisa O'Flynn
- Orbsen Therapeutics, National University of Ireland (NUIG), Galway, H91 TK33, Ireland
| | - Steve Elliman
- Orbsen Therapeutics, National University of Ireland (NUIG), Galway, H91 TK33, Ireland
| | - Timothy O'Brien
- Regenerative Medicine Institute and Department of Medicine, NUIG, Galway, H91 TK33, Ireland
| | - Carsten Tschöpe
- Berlin-Brandenburg Center for Regenerative Therapies and Berlin Institute of Health Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, Campus Virchow Klinikum (CVK), Berlin, 13353 and 10178, Germany
- German Center for Cardiovascular Research (DZHK), Partner site Berlin, Berlin, 13347, Germany
- Department of Cardiology, Charité - Universitätsmedizin Berlin, CVK, Berlin, 13353, Germany
| | - Sophie Van Linthout
- Berlin-Brandenburg Center for Regenerative Therapies and Berlin Institute of Health Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, Campus Virchow Klinikum (CVK), Berlin, 13353 and 10178, Germany
- German Center for Cardiovascular Research (DZHK), Partner site Berlin, Berlin, 13347, Germany
| |
Collapse
|
13
|
Species differences in cardiovascular physiology that affect pharmacology and toxicology. CURRENT OPINION IN TOXICOLOGY 2020. [DOI: 10.1016/j.cotox.2020.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
14
|
Marston S, Jacques A, Bayliss C, Dyer E, Memo M, Papadaki M, Messer A. Donor hearts in the Sydney Heart Bank: reliable control but is it 'normal' heart? Biophys Rev 2020; 12:799-803. [PMID: 32691299 PMCID: PMC7429572 DOI: 10.1007/s12551-020-00740-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/09/2020] [Indexed: 11/01/2022] Open
Abstract
Human heart samples from the Sydney Heart Bank have become a de facto standard against which others can be measured. Crucially, the heart bank contains a lot of donor heart material: for most researchers this is the hardest to obtain and yet is necessary since we can only study the pathological human heart in comparison with a control, preferably a normal heart sample. It is not generally realised how important the control is for human heart studies. We review our studies on donor heart samples. We report the results obtained with 17 different donor samples collected from 1994 to 2011 and measured from 2005 to 2015 by our standard methodology for in vitro motility and troponin I phosphorylation measurements. The donor heart sample parameters are consistent between the hearts, over time and with different operators indicating that Sydney Heart Bank donor hearts are a valid baseline control for comparison with pathological heart samples. We also discuss to what extent donor heart samples are representative of the normal heart.
Collapse
Affiliation(s)
- Steven Marston
- NHLI, Imperial College London, London, W12 0NN, UK. .,Cardiovascular Division, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus Du Cane Road, London, W12 0NN, UK.
| | - Adam Jacques
- Cardiology Department, St Peters Hospital, Chertsey, KT16 0PZ, UK
| | | | - Emma Dyer
- Intensive Care Unit, Royal Surrey County Hospital, Guildford, GU2 7XX, UK
| | | | - Maria Papadaki
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, IL, USA
| | | |
Collapse
|
15
|
McDonald KS, Hanft LM, Robinett JC, Guglin M, Campbell KS. Regulation of Myofilament Contractile Function in Human Donor and Failing Hearts. Front Physiol 2020; 11:468. [PMID: 32523542 PMCID: PMC7261867 DOI: 10.3389/fphys.2020.00468] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/16/2020] [Indexed: 01/14/2023] Open
Abstract
Heart failure (HF) often includes changes in myocardial contractile function. This study addressed the myofibrillar basis for contractile dysfunction in failing human myocardium. Regulation of contractile properties was measured in cardiac myocyte preparations isolated from frozen, left ventricular mid-wall biopsies of donor (n = 7) and failing human hearts (n = 8). Permeabilized cardiac myocyte preparations were attached between a force transducer and a position motor, and both the Ca2+ dependence and sarcomere length (SL) dependence of force, rate of force, loaded shortening, and power output were measured at 15 ± 1°C. The myocyte preparation size was similar between groups (donor: length 148 ± 10 μm, width 21 ± 2 μm, n = 13; HF: length 131 ± 9 μm, width 23 ± 1 μm, n = 16). The maximal Ca2+-activated isometric force was also similar between groups (donor: 47 ± 4 kN⋅m-2; HF: 44 ± 5 kN⋅m-2), which implicates that previously reported force declines in multi-cellular preparations reflect, at least in part, tissue remodeling. Maximal force development rates were also similar between groups (donor: k tr = 0.60 ± 0.05 s-1; HF: k tr = 0.55 ± 0.04 s-1), and both groups exhibited similar Ca2+ activation dependence of k tr values. Human cardiac myocyte preparations exhibited a Ca2+ activation dependence of loaded shortening and power output. The peak power output normalized to isometric force (PNPO) decreased by ∼12% from maximal Ca2+ to half-maximal Ca2+ activations in both groups. Interestingly, the SL dependence of PNPO was diminished in failing myocyte preparations. During sub-maximal Ca2+ activation, a reduction in SL from ∼2.25 to ∼1.95 μm caused a ∼26% decline in PNPO in donor myocytes but only an ∼11% change in failing myocytes. These results suggest that altered length-dependent regulation of myofilament function impairs ventricular performance in failing human hearts.
Collapse
Affiliation(s)
- Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Laurin M. Hanft
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Joel C. Robinett
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Maya Guglin
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, United States
| | - Kenneth S. Campbell
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, United States
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| |
Collapse
|
16
|
Ren X, Johns RA, Gao WD. EXPRESS: Right Heart in Pulmonary Hypertension: From Adaptation to Failure. Pulm Circ 2019; 9:2045894019845611. [PMID: 30942134 PMCID: PMC6681271 DOI: 10.1177/2045894019845611] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 03/27/2019] [Indexed: 01/24/2023] Open
Abstract
Right ventricular (RV) failure (RVF) has garnered significant attention in recent years because of its negative impact on clinical outcomes in patients with pulmonary hypertension (PH). PH triggers a series of events, including activation of several signaling pathways that regulate cell growth, metabolism, extracellular matrix remodeling, and energy production. These processes render the RV adaptive to PH. However, RVF develops when PH persists, accompanied by RV ischemia, alterations in substrate and mitochondrial energy metabolism, increased free oxygen radicals, increased cell loss, downregulation of adrenergic receptors, increased inflammation and fibrosis, and pathologic microRNAs. Diastolic dysfunction is also an integral part of RVF. Emerging non-invasive technologies such as molecular or metallic imaging, cardiac MRI, and ultrafast Doppler coronary flow mapping will be valuable tools to monitor RVF, especially the transition to RVF. Most PH therapies cannot treat RVF once it has occurred. A variety of therapies are available to treat acute and chronic RVF, but they are mainly supportive, and no effective therapy directly targets the failing RV. Therapies that target cell growth, cellular metabolism, oxidative stress, and myocyte regeneration are being tested preclinically. Future research should include establishing novel RVF models based on existing models, increasing use of human samples, creating human stem cell-based in vitro models, and characterizing alterations in cardiac excitation–contraction coupling during transition from adaptive RV to RVF. More successful strategies to manage RVF will likely be developed as we learn more about the transition from adaptive remodeling to maladaptive RVF in the future.
Collapse
Affiliation(s)
- Xianfeng Ren
- Department of Anesthesiology,
China-Japan
Friendship Hospital, Beijing, China
| | - Roger A. Johns
- Department of Anesthesiology and
Critical Care Medicine,
Johns
Hopkins University School of Medicine,
Baltimore, MD, USA
| | - Wei Dong Gao
- Department of Anesthesiology and
Critical Care Medicine,
Johns
Hopkins University School of Medicine,
Baltimore, MD, USA
| |
Collapse
|
17
|
Lin Z, Guo F, Gregorich ZR, Sun R, Zhang H, Hu Y, Shanmuganayagam D, Ge Y. Comprehensive Characterization of Swine Cardiac Troponin T Proteoforms by Top-Down Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:1284-1294. [PMID: 29633223 PMCID: PMC6109964 DOI: 10.1007/s13361-018-1925-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/14/2018] [Accepted: 02/14/2018] [Indexed: 05/12/2023]
Abstract
Cardiac troponin T (cTnT) regulates the Ca2+-mediated interaction between myosin thick filaments and actin thin filaments during cardiac contraction and relaxation. cTnT is released into the blood following injury, and increased serum levels of the protein are used clinically as a biomarker for myocardial infarction. Moreover, mutations in cTnT are causative in a number of familial cardiomyopathies. With the increasing use of large animal (swine) model to recapitulate human diseases, it is essential to characterize species-dependent protein sequence variants, alternative RNA splicing, and post-translational modifications (PTMs), but challenges remain due to the incomplete database and lack of validation of the predicted splicing isoforms. Herein, we integrated top-down mass spectrometry (MS) with online liquid chromatography (LC) and immunoaffinity purification to comprehensively characterize miniature swine cTnT proteoforms, including those arising from alternative RNA splicing and PTMs. A total of seven alternative splicing isoforms of cTnT were identified by LC/MS from swine left ventricular tissue, with each isoform containing un-phosphorylated and mono-phosphorylated proteoforms. The phosphorylation site was localized to Ser1 for the mono-phosphorylated proteoforms of cTnT1, 3, 4, and 6 by online MS/MS combining collisionally activated dissociation (CAD) and electron transfer dissociation (ETD). Offline MS/MS on Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer with CAD and electron capture dissociation (ECD) was then utilized to achieve deep sequencing of mono-phosphorylated cTnT1 (35.2 kDa) with a high sequence coverage of 87%. Taken together, this study demonstrated the unique advantage of top-down MS in the comprehensive characterization of protein alternative splicing isoforms together with PTMs. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Ziqing Lin
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Human Proteomics Program, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Fang Guo
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Department of Cardiology, Shandong Provincial Hospital, Jinan, 250021, Shandong, People's Republic of China
| | - Zachery R Gregorich
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Ruixiang Sun
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Institute of Computing Technology, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China
| | - Han Zhang
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Yang Hu
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | | | - Ying Ge
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53705, USA.
- Human Proteomics Program, University of Wisconsin-Madison, Madison, WI, 53705, USA.
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
| |
Collapse
|
18
|
Tampering with springs: phosphorylation of titin affecting the mechanical function of cardiomyocytes. Biophys Rev 2017; 9:225-237. [PMID: 28510118 PMCID: PMC5498327 DOI: 10.1007/s12551-017-0263-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 03/26/2017] [Indexed: 12/17/2022] Open
Abstract
Reversible post-translational modifications of various cardiac proteins regulate the mechanical properties of the cardiomyocytes and thus modulate the contractile performance of the heart. The giant protein titin forms a continuous filament network in the sarcomeres of striated muscle cells, where it determines passive tension development and modulates active contraction. These mechanical properties of titin are altered through post-translational modifications, particularly phosphorylation. Titin contains hundreds of potential phosphorylation sites, the functional relevance of which is only beginning to emerge. Here, we provide a state-of-the-art summary of the phosphorylation sites in titin, with a particular focus on the elastic titin spring segment. We discuss how phosphorylation at specific amino acids can reduce or increase the stretch-induced spring force of titin, depending on where the spring region is phosphorylated. We also review which protein kinases phosphorylate titin and how this phosphorylation affects titin-based passive tension in cardiomyocytes. A comprehensive overview is provided of studies that have measured altered titin phosphorylation and titin-based passive tension in myocardial samples from human heart failure patients and animal models of heart disease. As our understanding of the broader implications of phosphorylation in titin progresses, this knowledge could be used to design targeted interventions aimed at reducing pathologically increased titin stiffness in patients with stiff hearts.
Collapse
|
19
|
Siddiqui JK, Tikunova SB, Walton SD, Liu B, Meyer M, de Tombe PP, Neilson N, Kekenes-Huskey PM, Salhi HE, Janssen PML, Biesiadecki BJ, Davis JP. Myofilament Calcium Sensitivity: Consequences of the Effective Concentration of Troponin I. Front Physiol 2016; 7:632. [PMID: 28066265 PMCID: PMC5175494 DOI: 10.3389/fphys.2016.00632] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 12/05/2016] [Indexed: 12/04/2022] Open
Abstract
Control of calcium binding to and dissociation from cardiac troponin C (TnC) is essential to healthy cardiac muscle contraction/relaxation. There are numerous aberrant post-translational modifications and mutations within a plethora of contractile, and even non-contractile, proteins that appear to imbalance this delicate relationship. The direction and extent of the resulting change in calcium sensitivity is thought to drive the heart toward one type of disease or another. There are a number of molecular mechanisms that may be responsible for the altered calcium binding properties of TnC, potentially the most significant being the ability of the regulatory domain of TnC to bind the switch peptide region of TnI. Considering TnI is essentially tethered to TnC and cannot diffuse away in the absence of calcium, we suggest that the apparent calcium binding properties of TnC are highly dependent upon an “effective concentration” of TnI available to bind TnC. Based on our previous work, TnI peptide binding studies and the calcium binding properties of chimeric TnC-TnI fusion constructs, and building upon the concept of effective concentration, we have developed a mathematical model that can simulate the steady-state and kinetic calcium binding properties of a wide assortment of disease-related and post-translational protein modifications in the isolated troponin complex and reconstituted thin filament. We predict that several TnI and TnT modifications do not alter any of the intrinsic calcium or TnI binding constants of TnC, but rather alter the ability of TnC to “find” TnI in the presence of calcium. These studies demonstrate the apparent consequences of the effective TnI concentration in modulating the calcium binding properties of TnC.
Collapse
Affiliation(s)
- Jalal K Siddiqui
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| | - Svetlana B Tikunova
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| | - Shane D Walton
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| | - Bin Liu
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| | - Meredith Meyer
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| | - Pieter P de Tombe
- Cell and Molecular Physiology, Loyola University Chicago Maywood, IL, USA
| | - Nathan Neilson
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| | | | - Hussam E Salhi
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| | - Jonathan P Davis
- Department of Physiology and Cell Biology and the Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA
| |
Collapse
|
20
|
Gresham KS, Mamidi R, Li J, Kwak H, Stelzer JE. Sarcomeric protein modification during adrenergic stress enhances cross-bridge kinetics and cardiac output. J Appl Physiol (1985) 2016; 122:520-530. [PMID: 27909224 DOI: 10.1152/japplphysiol.00306.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 10/21/2016] [Accepted: 11/23/2016] [Indexed: 12/23/2022] Open
Abstract
Molecular adaptations to chronic neurohormonal stress, including sarcomeric protein cleavage and phosphorylation, provide a mechanism to increase ventricular contractility and enhance cardiac output, yet the link between sarcomeric protein modifications and changes in myocardial function remains unclear. To examine the effects of neurohormonal stress on posttranslational modifications of sarcomeric proteins, mice were administered combined α- and β-adrenergic receptor agonists (isoproterenol and phenylephrine, IPE) for 14 days using implantable osmotic pumps. In addition to significant cardiac hypertrophy and increased maximal ventricular pressure, IPE treatment accelerated pressure development and relaxation (74% increase in dP/dtmax and 14% decrease in τ), resulting in a 52% increase in cardiac output compared with saline (SAL)-treated mice. Accelerated pressure development was maintained when accounting for changes in heart rate and preload, suggesting that myocardial adaptations contribute to enhanced ventricular contractility. Ventricular myocardium isolated from IPE-treated mice displayed a significant reduction in troponin I (TnI) and myosin-binding protein C (MyBP-C) expression and a concomitant increase in the phosphorylation levels of the remaining TnI and MyBP-C protein compared with myocardium isolated from saline-treated control mice. Skinned myocardium isolated from IPE-treated mice displayed a significant acceleration in the rate of cross-bridge (XB) detachment (46% increase) and an enhanced magnitude of XB recruitment (43% increase) at submaximal Ca2+ activation compared with SAL-treated mice but unaltered myofilament Ca2+ sensitivity of force generation. These findings demonstrate that sarcomeric protein modifications during neurohormonal stress are molecular adaptations that enhance in vivo ventricular contractility through accelerated XB kinetics to increase cardiac output.NEW & NOTEWORTHY Posttranslational modifications to sarcomeric regulatory proteins provide a mechanism to modulate cardiac function in response to stress. In this study, we demonstrate that neurohormonal stress produces modifications to myosin-binding protein C and troponin I, including a reduction in protein expression within the sarcomere and increased phosphorylation of the remaining protein, which serve to enhance cross-bridge kinetics and increase cardiac output. These findings highlight the importance of sarcomeric regulatory protein modifications in modulating ventricular function during cardiac stress.
Collapse
Affiliation(s)
- Kenneth S Gresham
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Jiayang Li
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Hyerin Kwak
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| |
Collapse
|
21
|
Gresham KS, Stelzer JE. The contributions of cardiac myosin binding protein C and troponin I phosphorylation to β-adrenergic enhancement of in vivo cardiac function. J Physiol 2016; 594:669-86. [PMID: 26635197 DOI: 10.1113/jp270959] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 11/30/2015] [Indexed: 01/12/2023] Open
Abstract
KEY POINTS β-adrenergic stimulation increases cardiac myosin binding protein C (MyBP-C) and troponin I phosphorylation to accelerate pressure development and relaxation in vivo, although their relative contributions remain unknown. Using a novel mouse model lacking protein kinase A-phosphorylatable troponin I (TnI) and MyBP-C, we examined in vivo haemodynamic function before and after infusion of the β-agonist dobutamine. Mice expressing phospho-ablated MyBP-C displayed cardiac hypertrophy and prevented full acceleration of pressure development and relaxation in response to dobutamine, whereas expression of phosphor-ablated TnI alone had little effect on the acceleration of contractile function in response to dobutamine. Our data demonstrate that MyBP-C phosphorylation is the principal mediator of the contractile response to increased β-agonist stimulation in vivo. These results help us understand why MyBP-C dephosphorylation in the failing heart contributes to contractile dysfunction and decreased adrenergic reserve in response to acute stress. β-adrenergic stimulation plays a critical role in accelerating ventricular contraction and speeding relaxation to match cardiac output to changing circulatory demands. Two key myofilaments proteins, troponin I (TnI) and myosin binding protein-C (MyBP-C), are phosphorylated following β-adrenergic stimulation; however, their relative contributions to the enhancement of in vivo cardiac contractility are unknown. To examine the roles of TnI and MyBP-C phosphorylation in β-adrenergic-mediated enhancement of cardiac function, transgenic (TG) mice expressing non-phosphorylatable TnI protein kinase A (PKA) residues (i.e. serine to alanine substitution at Ser23/24; TnI(PKA-)) were bred with mice expressing non-phosphorylatable MyBP-C PKA residues (i.e. serine to alanine substitution at Ser273, Ser282 and Ser302; MyBPC(PKA-)) to generate a novel mouse model expressing non-phosphorylatable PKA residues in TnI and MyBP-C (DBL(PKA-)). MyBP-C dephosphorylation produced cardiac hypertrophy and increased wall thickness in MyBPC(PKA-) and DBL(PKA-) mice, and in vivo echocardiography and pressure-volume catheterization studies revealed impaired systolic function and prolonged diastolic relaxation compared to wild-type and TnI(PKA-) mice. Infusion of the β-agonist dobutamine resulted in accelerated rates of pressure development and relaxation in all mice; however, MyBPC(PKA-) and DBL(PKA-) mice displayed a blunted contractile response compared to wild-type and TnI(PKA-) mice. Furthermore, unanaesthesized MyBPC(PKA-) and DBL(PKA-) mice displayed depressed maximum systolic pressure in response to dobutamine as measured using implantable telemetry devices. Taken together, our data show that MyBP-C phosphorylation is a critical modulator of the in vivo acceleration of pressure development and relaxation as a result of enhanced β-adrenergic stimulation, and reduced MyBP-C phosphorylation may underlie depressed adrenergic reserve in heart failure.
Collapse
Affiliation(s)
- Kenneth S Gresham
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| |
Collapse
|
22
|
Pinti MV, Hathaway QA, Hollander JM. Role of microRNA in metabolic shift during heart failure. Am J Physiol Heart Circ Physiol 2016; 312:H33-H45. [PMID: 27742689 DOI: 10.1152/ajpheart.00341.2016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 10/07/2016] [Accepted: 10/08/2016] [Indexed: 12/16/2022]
Abstract
Heart failure (HF) is an end point resulting from a number of disease states. The prognosis for HF patients is poor with survival rates precipitously low. Energy metabolism is centrally linked to the development of HF, and it involves the proteomic remodeling of numerous pathways, many of which are targeted to the mitochondrion. microRNAs (miRNA) are noncoding RNAs that influence posttranscriptional gene regulation. miRNA have garnered considerable attention for their ability to orchestrate changes to the transcriptome, and ultimately the proteome, during HF. Recently, interest in the role played by miRNA in the regulation of energy metabolism at the mitochondrion has emerged. Cardiac proteome remodeling during HF includes axes impacting hypertrophy, oxidative stress, calcium homeostasis, and metabolic fuel transition. Although it is established that the pathological environment of hypoxia and hemodynamic stress significantly contribute to the HF phenotype, it remains unclear as to the mechanistic underpinnings driving proteome remodeling. The aim of this review is to present evidence highlighting the role played by miRNA in these processes as a means for linking pathological stimuli with proteomic alteration. The differential expression of proteins of substrate transport, glycolysis, β-oxidation, ketone metabolism, the citric acid cycle (CAC), and the electron transport chain (ETC) are paralleled by the differential expression of miRNA species that modulate these processes. Identification of miRNAs that translocate to cardiomyocyte mitochondria (miR-181c, miR-378) influencing the expression of the mitochondrial genome-encoded transcripts as well as suggested import modulators are discussed. Current insights, applications, and challenges of miRNA-based therapeutics are also described.
Collapse
Affiliation(s)
- Mark V Pinti
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia; and Mitochondria, Metabolism, and Bioenergentics Working Group, Morgantown, West Virginia
| | - Quincy A Hathaway
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia; and Mitochondria, Metabolism, and Bioenergentics Working Group, Morgantown, West Virginia
| | - John M Hollander
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia; and Mitochondria, Metabolism, and Bioenergentics Working Group, Morgantown, West Virginia
| |
Collapse
|
23
|
Lorenzen-Schmidt I, Clarke SB, Pyle WG. The neglected messengers: Control of cardiac myofilaments by protein phosphatases. J Mol Cell Cardiol 2016; 101:81-89. [PMID: 27721025 DOI: 10.1016/j.yjmcc.2016.10.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/03/2016] [Accepted: 10/05/2016] [Indexed: 01/21/2023]
Abstract
Cardiac myofilaments act as the central contractile apparatus of heart muscle cells. Covalent modification of constituent proteins through phosphorylation is a rapid and powerful mechanism to control myofilament function, and is increasingly seen as a mechanism of disease. While the relationship between protein kinases and cardiac myofilaments has been widely examined, the impact of protein dephosphorylation by protein phosphatases is poorly understood. This review outlines the mechanisms by which the mostly widely expressed protein phosphatases in cardiac myocytes regulate myofilament function, and the emerging role of myofilament-associated protein phosphatases in heart failure. The importance of regulatory subunits and subcellular compartmentalization in determining the functional impact of protein phosphatases on myofilament and myocardial function is also discussed, as are discrepancies about the roles of protein phosphatases in regulating myofilament function. The potential for targeting these molecular messengers in the treatment of heart failure is discussed as a key future direction.
Collapse
Affiliation(s)
- Ilka Lorenzen-Schmidt
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Samantha B Clarke
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - W Glen Pyle
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
| |
Collapse
|
24
|
Gong H, Li Y, Wang L, Lv Q, Wang X. Short-term effects of β2-AR blocker ICI 118,551 on sarcoplasmic reticulum SERCA2a and cardiac function of rats with heart failure. Exp Ther Med 2016; 12:1355-1362. [PMID: 27602067 PMCID: PMC4998176 DOI: 10.3892/etm.2016.3450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/13/2016] [Indexed: 01/15/2023] Open
Abstract
The study was conducted to examine the effects of ICI 118,551 on the systolic function of cardiac muscle cells of rats in heart failure and determine the molecular mechanism of selective β2-adrenergic receptor (β2-AR) antagonist on these cells. The chronic heart failure model for rats was prepared through abdominal aortic constriction and separate cardiac muscle cells using the collagenase digestion method. The rats were then divided into Sham, HF and HF+ICI 50 nM goups and cultivated for 48 h. β2-AR, Gi/Gs and sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) protein expression levels in the cardiac muscle cells were evaluated by western blotting and changes in the systolic function of cardiac muscle cells based on the boundary detection system of contraction dynamics for individual cells was measured. The results showed that compared with the Sham group, the survival rate, percentage of basic contraction and maximum contraction amplitude percentage of cardiac muscle cells with heart failure decreased, Gi protein expression increased while Gs and SERCA2a protein expression decreased. Compared with the HF group, the maximum contraction amplitude percentage of cardiac muscle cells in group HF+ICI 50 nM decreased, the Gi protein expression level increased while the SERCA2a protein expression level decreased. Following the stimulation of Ca2+ and ISO, the maximum contraction amplitude percentage of cardiac muscle cells in the HF+ICI 50 nM group was lower than that in group HF. This indicated that ICI 118,551 has negative inotropic effects on cardiac muscle cells with heart failure, which may be related to Gi protein. Systolic function of cardiac muscle cells with heart failure can therefore be reduced by increasing Gi protein expression and lowering SERCA2a protein expression.
Collapse
Affiliation(s)
- Haibin Gong
- Department of Cardiology, Xuzhou Central Hospital, Xuzhou Cardiovascular Disease Institute, Xuzhou, Jiangsu 221009, P.R. China
| | - Yanfei Li
- Department of Cardiology, Xuzhou Central Hospital, Xuzhou Cardiovascular Disease Institute, Xuzhou, Jiangsu 221009, P.R. China
| | - Lei Wang
- Department of Cardiology, Xuzhou Central Hospital, Xuzhou Cardiovascular Disease Institute, Xuzhou, Jiangsu 221009, P.R. China
| | - Qian Lv
- Department of Cardiology, Xuzhou Central Hospital, Xuzhou Cardiovascular Disease Institute, Xuzhou, Jiangsu 221009, P.R. China
| | - Xiuli Wang
- Department of Cardiology, Xuzhou Central Hospital, Xuzhou Cardiovascular Disease Institute, Xuzhou, Jiangsu 221009, P.R. China
| |
Collapse
|
25
|
Cheng Y, Hogarth KA, O'Sullivan ML, Regnier M, Pyle WG. 2-Deoxyadenosine triphosphate restores the contractile function of cardiac myofibril from adult dogs with naturally occurring dilated cardiomyopathy. Am J Physiol Heart Circ Physiol 2016; 310:H80-91. [PMID: 26497964 PMCID: PMC4796460 DOI: 10.1152/ajpheart.00530.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/08/2015] [Indexed: 11/22/2022]
Abstract
Dilated cardiomyopathy (DCM) is a major type of heart failure resulting from loss of systolic function. Naturally occurring canine DCM is a widely accepted experimental paradigm for studying human DCM. 2-Deoxyadenosine triphosphate (dATP) can be used by myosin and is a superior energy substrate over ATP for cross-bridge formation and increased systolic function. The objective of this study was to evaluate the beneficial effect of dATP on contractile function of cardiac myofibrils from dogs with naturally occurring DCM. We measured actomyosin NTPase activity and contraction/relaxation properties of isolated myofibrils from nonfailing (NF) and DCM canine hearts. NTPase assays indicated replacement of ATP with dATP significantly increased myofilament activity in both NF and DCM samples. dATP significantly improved maximal tension of DCM myofibrils to the NF sample level. dATP also restored Ca(2+) sensitivity of tension that was reduced in DCM samples. Similarly, dATP increased the kinetics of contractile activation (kACT), with no impact on the rate of cross-bridge tension redevelopment (kTR). Thus, the activation kinetics (kACT/kTR) that were reduced in DCM samples were restored for dATP to NF sample levels. dATP had little effect on relaxation. The rate of early slow-phase relaxation was slightly reduced with dATP, but its duration was not, nor was the fast-phase relaxation or times to 50 and 90% relaxation. Our findings suggest that myosin utilization of dATP improves cardiac myofibril contractile properties of naturally occurring DCM canine samples, restoring them to NF levels, without compromising relaxation. This suggests elevation of cardiac dATP is a promising approach for the treatment of DCM.
Collapse
Affiliation(s)
- Yuanhua Cheng
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Kaley A Hogarth
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and
| | - M Lynne O'Sullivan
- Department of Clinical Studies, University of Guelph, Guelph, Ontario, Canada
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - W Glen Pyle
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and
| |
Collapse
|
26
|
Dubois-Deruy E, Belliard A, Mulder P, Bouvet M, Smet-Nocca C, Janel S, Lafont F, Beseme O, Amouyel P, Richard V, Pinet F. Interplay between troponin T phosphorylation and O-N-acetylglucosaminylation in ischaemic heart failure. Cardiovasc Res 2015; 107:56-65. [PMID: 25916824 DOI: 10.1093/cvr/cvv136] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 04/15/2015] [Indexed: 11/13/2022] Open
Abstract
AIMS Previous studies have reported that decreased serine 208 phosphorylation of troponin T (TnTpSer208) is associated with ischaemic heart failure (HF), but the molecular mechanisms and functional consequences of these changes are unknown. The aim of this study was to characterize the balance between serine phosphorylation and O-N-acetylglucosaminylation (O-GlcNAcylation) of TnT in HF, its mechanisms, and the consequences of modulating these post-translational modifications. METHODS AND RESULTS Decreased TnTpSer208 levels in the left ventricles of HF male Wistar rats were associated with reduced expression of PKCε but not of other cardiac PKC isoforms. In both isolated perfused rat hearts and cultured neonatal cardiomyocytes, the PKCε inhibitor εV1-2 decreased TnTpSer208 and simultaneously decreased cardiac contraction in isolated hearts and beating amplitude in neonatal cardiomyocytes (measured by atomic force microscopy). Down-regulating PKCε by silencing RNA (siRNA) also reduced TnTpSer208 in these cardiomyocytes, and PKCε-/- mice had lower TnTpSer208 levels than the wild-type. In parallel, HF increased TnT O-GlcNAcylation via both increased O-GlcNAc transferase and decreased O-GlcNAcase activity. Increasing O-GlcNAcylation (via O-GlcNAcase inhibition with Thiamet G) decreased TnTpSer208 in isolated hearts, while reducing O-GlcNAcylation (O-GlcNAc transferase siRNA) increased TnTpSer208 in neonatal cardiomyocytes. Mass spectrometry and NMR analysis identified O-GlcNAcylation of TnT on Ser190. CONCLUSION These data demonstrate interplay between Ser208 phosphorylation and Ser190 O-GlcNAcylation of TnT in ischaemic HF, linked to decreased activity of both PKCε and O-GlcNAcase and increased O-GlcNAc transferase activity. Modulation of these post-translational modifications of TnT may be a new therapeutic strategy in HF.
Collapse
Affiliation(s)
- Emilie Dubois-Deruy
- INSERM, U1167, 1 rue du Professeur Calmette, Lille, France Institut Pasteur de Lille, Lille, France University of Lille Nord de France, Lille, France
| | - Aude Belliard
- INSERM, U1167, 1 rue du Professeur Calmette, Lille, France Institut Pasteur de Lille, Lille, France University of Lille Nord de France, Lille, France
| | - Paul Mulder
- Inserm U1096, Rouen, France Institute for Research and Innovation in Biomedicine, University of Rouen, Rouen, France
| | - Marion Bouvet
- INSERM, U1167, 1 rue du Professeur Calmette, Lille, France Institut Pasteur de Lille, Lille, France University of Lille Nord de France, Lille, France
| | - Caroline Smet-Nocca
- University of Lille Nord de France, Lille, France CNRS UMR 8576, Villeneuve D'Ascq, France
| | | | - Frank Lafont
- Institut Pasteur de Lille, Lille, France University of Lille Nord de France, Lille, France Bioimaging Center Lille Nord de France, Lille, France CNRS UMR 8204, INSERM U1019, Lille, France
| | - Olivia Beseme
- INSERM, U1167, 1 rue du Professeur Calmette, Lille, France Institut Pasteur de Lille, Lille, France University of Lille Nord de France, Lille, France
| | - Philippe Amouyel
- INSERM, U1167, 1 rue du Professeur Calmette, Lille, France Institut Pasteur de Lille, Lille, France University of Lille Nord de France, Lille, France Centre Hospitalier Régional et Universitaire de Lille, Lille, France
| | - Vincent Richard
- Inserm U1096, Rouen, France Institute for Research and Innovation in Biomedicine, University of Rouen, Rouen, France
| | - Florence Pinet
- INSERM, U1167, 1 rue du Professeur Calmette, Lille, France Institut Pasteur de Lille, Lille, France University of Lille Nord de France, Lille, France
| |
Collapse
|
27
|
Zile MR, Baicu CF, Ikonomidis JS, Stroud RE, Nietert PJ, Bradshaw AD, Slater R, Palmer BM, Van Buren P, Meyer M, Redfield MM, Bull DA, Granzier HL, LeWinter MM. Myocardial stiffness in patients with heart failure and a preserved ejection fraction: contributions of collagen and titin. Circulation 2015; 131:1247-59. [PMID: 25637629 DOI: 10.1161/circulationaha.114.013215] [Citation(s) in RCA: 473] [Impact Index Per Article: 52.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 01/26/2015] [Indexed: 12/15/2022]
Abstract
BACKGROUND The purpose of this study was to determine whether patients with heart failure and a preserved ejection fraction (HFpEF) have an increase in passive myocardial stiffness and the extent to which discovered changes depend on changes in extracellular matrix fibrillar collagen and cardiomyocyte titin. METHODS AND RESULTS Seventy patients undergoing coronary artery bypass grafting underwent an echocardiogram, plasma biomarker determination, and intraoperative left ventricular epicardial anterior wall biopsy. Patients were divided into 3 groups: referent control (n=17, no hypertension or diabetes mellitus), hypertension (HTN) without (-) HFpEF (n=31), and HTN with (+) HFpEF (n=22). One or more of the following studies were performed on the biopsies: passive stiffness measurements to determine total, collagen-dependent and titin-dependent stiffness (differential extraction assay), collagen assays (biochemistry or histology), or titin isoform and phosphorylation assays. In comparison with controls, patients with HTN(-)HFpEF had no change in left ventricular end-diastolic pressure, myocardial passive stiffness, collagen, or titin phosphorylation but had an increase in biomarkers of inflammation (C-reactive protein, soluble ST2, tissue inhibitor of metalloproteinase 1). In comparison with both control and HTN(-)HFpEF, patients with HTN(+)HFpEF had increased left ventricular end-diastolic pressure, left atrial volume, N-terminal propeptide of brain natriuretic peptide, total, collagen-dependent, and titin-dependent stiffness, insoluble collagen, increased titin phosphorylation on PEVK S11878(S26), reduced phosphorylation on N2B S4185(S469), and increased biomarkers of inflammation. CONCLUSIONS Hypertension in the absence of HFpEF did not alter passive myocardial stiffness. Patients with HTN(+)HFpEF had a significant increase in passive myocardial stiffness; collagen-dependent and titin-dependent stiffness were increased. These data suggest that the development of HFpEF depends on changes in both collagen and titin homeostasis.
Collapse
Affiliation(s)
- Michael R Zile
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.).
| | - Catalin F Baicu
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - John S Ikonomidis
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Robert E Stroud
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Paul J Nietert
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Amy D Bradshaw
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Rebecca Slater
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Bradley M Palmer
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Peter Van Buren
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Markus Meyer
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Margaret M Redfield
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - David A Bull
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Henk L Granzier
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| | - Martin M LeWinter
- From Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (M.R.Z., C.F.B., A.D.B.); Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC (J.S.I., R.E.S.); Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC (P.J.N.); Department of Cellular and Molecular Medicine, University of Arizona, Tucson (R.S., H.L.G.); Cardiology Unit, Department of Medicine, University of Vermont, Burlington (B.M.P., P.V.B., M.M., M.M.L.W.); Department of Molecular Physiology and Biophysics, University of Vermont, Burlington (B.M.P., P.V.B., M.M.L.W.); Division of Cardiology, Mayo Clinic, Rochester, MN (M.M.R.); and Division of Cardiothoracic Surgery, Department of Surgery, University of Utah Health Sciences Center, Salt Lake City (D.A.B.)
| |
Collapse
|
28
|
Kuster DW, Merkus D, Blonden LA, Kremer A, van IJcken WF, Verhoeven AJ, Duncker DJ. Gene reprogramming in exercise-induced cardiac hypertrophy in swine: A transcriptional genomics approach. J Mol Cell Cardiol 2014; 77:168-74. [DOI: 10.1016/j.yjmcc.2014.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/22/2014] [Accepted: 10/13/2014] [Indexed: 10/24/2022]
|
29
|
Gandhi A, Siedlecka U, Shah AP, Navaratnarajah M, Yacoub MH, Terracciano CM. The effect of SN-6, a novel sodium-calcium exchange inhibitor, on contractility and calcium handling in isolated failing rat ventricular myocytes. Cardiovasc Ther 2014; 31:e115-24. [PMID: 24106913 DOI: 10.1111/1755-5922.12045] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Specific Na(+) /Ca(2+) exchanger (NCX) inhibition is a potential strategy to correct reduced contractility and depleted sarcoplasmic reticulum (SR) Ca(2+) content in heart failure (HF). SN-6, a benzyloxyphenyl derivative and proposed selective NCX inhibitor, could be used for this purpose. This study aimed to evaluate the effects of SN-6 on contractility and Ca(2+) handling in normal and failing rat cardiomyocytes. EXPERIMENTAL APPROACH HF was induced in rats by coronary artery ligation. Left ventricular myocytes were isolated and superfused with increasing concentrations of SN-6. KEY RESULTS Sarcomere shortening, induced by field-stimulation, was reduced in amplitude with increasing concentrations of SN-6 compared with control solution. This effect was greater in failing cells. Kinetics of contractility (time to 90% peak and time to 50% relaxation) were significantly faster. Despite this, intracellular Ca(2+) transients demonstrated no change in the peak amplitude at low concentrations of SN-6, suggesting that SN-6 may affect myofilament sensitivity to Ca(2+) . Ten micro molar SN-6 significantly reduced peak Ca(2+) amplitude by 61.57% and 64.73% in normal and failing cells, respectively. Diastolic Ca(2+) was significantly increased at 1 μM SN-6. SR Ca(2+) content, assessed by rapid application of caffeine, was reduced in failing cells with 1 μM SN-6. Peak ICa , measured by whole-cell patch clamping, was significantly reduced in normal and failing myocytes at 1 μM SN-6. CONCLUSIONS AND IMPLICATIONS Our data suggest that SN-6 is not a selective inhibitor of NCX and impairs contractility and Ca(2+) handling. Its use, together with similar putative NCX blockers, in correcting the contractile abnormalities of heart failure requires further studies.
Collapse
Affiliation(s)
- Ajay Gandhi
- Cell Electrophysiology, Heart Science Centre, NHLI, Imperial College London, London, UK
| | | | | | | | | | | |
Collapse
|
30
|
Messer AE, Marston SB. Investigating the role of uncoupling of troponin I phosphorylation from changes in myofibrillar Ca(2+)-sensitivity in the pathogenesis of cardiomyopathy. Front Physiol 2014; 5:315. [PMID: 25202278 PMCID: PMC4142463 DOI: 10.3389/fphys.2014.00315] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 08/02/2014] [Indexed: 12/12/2022] Open
Abstract
Contraction in the mammalian heart is controlled by the intracellular Ca(2+) concentration as it is in all striated muscle, but the heart has an additional signaling system that comes into play to increase heart rate and cardiac output during exercise or stress. β-adrenergic stimulation of heart muscle cells leads to release of cyclic-AMP and the activation of protein kinase A which phosphorylates key proteins in the sarcolemma, sarcoplasmic reticulum and contractile apparatus. Troponin I (TnI) and Myosin Binding Protein C (MyBP-C) are the prime targets in the myofilaments. TnI phosphorylation lowers myofibrillar Ca(2+)-sensitivity and increases the speed of Ca(2+)-dissociation and relaxation (lusitropic effect). Recent studies have shown that this relationship between Ca(2+)-sensitivity and TnI phosphorylation may be unstable. In familial cardiomyopathies, both dilated and hypertrophic (DCM and HCM), a mutation in one of the proteins of the thin filament often results in the loss of the relationship (uncoupling) and blunting of the lusitropic response. For familial dilated cardiomyopathy in thin filament proteins it has been proposed that this uncoupling is causative of the phenotype. Uncoupling has also been found in human heart tissue from patients with hypertrophic obstructive cardiomyopathy as a secondary effect. Recently, it has been found that Ca(2+)-sensitizing drugs can promote uncoupling, whilst one Ca(2+)-desensitizing drug Epigallocatechin 3-Gallate (EGCG) can reverse uncoupling. We will discuss recent findings about the role of uncoupling in the development of cardiomyopathies and the molecular mechanism of the process.
Collapse
Affiliation(s)
- Andrew E. Messer
- National Heart & Lung Institute, Imperial College LondonLondon, UK
| | | |
Collapse
|
31
|
Shimkunas R, Makwana O, Spaulding K, Bazargan M, Khazalpour M, Takaba K, Soleimani M, Myagmar BE, Lovett DH, Simpson PC, Ratcliffe MB, Baker AJ. Myofilament dysfunction contributes to impaired myocardial contraction in the infarct border zone. Am J Physiol Heart Circ Physiol 2014; 307:H1150-8. [PMID: 25128171 DOI: 10.1152/ajpheart.00463.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
After myocardial infarction, a poorly contracting nonischemic border zone forms adjacent to the infarct. The cause of border zone dysfunction is unclear. The goal of this study was to determine the myofilament mechanisms involved in postinfarction border zone dysfunction. Two weeks after anteroapical infarction of sheep hearts, we studied in vitro isometric and isotonic contractions of demembranated myocardium from the infarct border zone and a zone remote from the infarct. Maximal force development (Fmax) of the border zone myocardium was reduced by 31 ± 2% versus the remote zone myocardium (n = 6/group, P < 0.0001). Decreased border zone Fmax was not due to a reduced content of contractile material, as assessed histologically, and from myosin content. Furthermore, decreased border zone Fmax did not involve altered cross-bridge kinetics, as assessed by muscle shortening velocity and force development kinetics. Decreased border zone Fmax was associated with decreased cross-bridge formation, as assessed from muscle stiffness in the absence of ATP where cross-bridge formation should be maximized (rigor stiffness was reduced 34 ± 6%, n = 5, P = 0.011 vs. the remote zone). Furthermore, the border zone myocardium had significantly reduced phosphorylation of myosin essential light chain (ELC; 41 ± 10%, n = 4, P < 0.05). However, for animals treated with doxycycline, an inhibitor of matrix metalloproteinases, rigor stiffness and ELC phosphorylation were not reduced in the border zone myocardium, suggesting that doxycycline had a protective effect. In conclusion, myofilament dysfunction contributes to postinfarction border zone dysfunction, myofilament dysfunction involves impaired cross-bridge formation and decreased ELC phosphorylation, and matrix metalloproteinase inhibition may be beneficial for limiting postinfarct border zone dysfunction.
Collapse
Affiliation(s)
- Rafael Shimkunas
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Om Makwana
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Kimberly Spaulding
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Mona Bazargan
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Michael Khazalpour
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Kiyoaki Takaba
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Mehrdad Soleimani
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Bat-Erdene Myagmar
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - David H Lovett
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Paul C Simpson
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Mark B Ratcliffe
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| | - Anthony J Baker
- Veterans Affairs Medical Center, San Francisco, California; and Departments of Medicine and Surgery, University of California-San Francisco (UCSF), Joint University of California-Berkeley/UCSF Bioengineering Group, San Francisco, California
| |
Collapse
|
32
|
Kalász J, Tóth EP, Bódi B, Fagyas M, Tóth A, Pal BH, Vari SG, Balog M, Blažetić S, Heffer M, Papp Z, Borbély A. Single acute stress-induced progesterone and ovariectomy alter cardiomyocyte contractile function in female rats. Croat Med J 2014; 55:239-49. [PMID: 24891282 PMCID: PMC4049214 DOI: 10.3325/cmj.2014.55.239] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Aim To assess how ovarian-derived sex hormones (in particular progesterone) modify the effects of single acute stress on the mechanical and biochemical properties of left ventricular cardiomyocytes in the rat. Methods Non-ovariectomized (control, n = 8) and ovariectomized (OVX, n = 8) female rats were kept under normal conditions or were exposed to stress (control-S, n = 8 and OVX-S, n = 8). Serum progesterone levels were measured using a chemiluminescent immunoassay. Left ventricular myocardial samples were used for isometric force measurements and protein analysis. Ca2+-dependent active force (Factive), Ca2+-independent passive force (Fpassive), and Ca2+-sensitivity of force production were determined in single, mechanically isolated, permeabilized cardiomyocytes. Stress- and ovariectomy-induced alterations in myofilament proteins (myosin-binding protein C [MyBP-C], troponin I [TnI], and titin) were analyzed by sodium dodecyl sulfate gel electrophoresis using protein and phosphoprotein stainings. Results Serum progesterone levels were significantly increased in stressed rats (control-S, 35.6 ± 4.8 ng/mL and OVX-S, 21.9 ± 4.0 ng/mL) compared to control (10 ± 2.9 ng/mL) and OVX (2.8 ± 0.5 ng/mL) groups. Factive was higher in the OVX groups (OVX, 25.9 ± 3.4 kN/m2 and OVX-S, 26.3 ± 3.0 kN/m2) than in control groups (control, 16.4 ± 1.2 kN/m2 and control-S, 14.4 ± 0.9 kN/m2). Regarding the potential molecular mechanisms, Factive correlated with MyBP-C phosphorylation, while myofilament Ca2+-sensitivity inversely correlated with serum progesterone levels when the mean values were plotted for all animal groups. Fpassive was unaffected by any treatment. Conclusion Stress increases ovary-independent synthesis and release of progesterone, which may regulate Ca2+-sensitivity of force production in left ventricular cardiomyocytes. Stress and female hormones differently alter Ca2+-dependent cardiomyocyte contractile force production, which may have pathophysiological importance during stress conditions affecting postmenopausal women.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Attila Borbély
- Attila Borbély, University of Debrecen, Institute of Cardiology, Division of Clinical Physiology, Móricz Zsigmond krt. 22, H-4032 Debrecen, Hungary,
| |
Collapse
|
33
|
Nixon BR, Walton SD, Zhang B, Brundage EA, Little SC, Ziolo MT, Davis JP, Biesiadecki BJ. Combined troponin I Ser-150 and Ser-23/24 phosphorylation sustains thin filament Ca(2+) sensitivity and accelerates deactivation in an acidic environment. J Mol Cell Cardiol 2014; 72:177-85. [PMID: 24657721 PMCID: PMC4075059 DOI: 10.1016/j.yjmcc.2014.03.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 03/10/2014] [Accepted: 03/13/2014] [Indexed: 01/09/2023]
Abstract
The binding of Ca(2+) to troponin C (TnC) in the troponin complex is a critical step regulating the thin filament, the actin-myosin interaction and cardiac contraction. Phosphorylation of the troponin complex is a key regulatory mechanism to match cardiac contraction to demand. Here we demonstrate that phosphorylation of the troponin I (TnI) subunit is simultaneously increased at Ser-150 and Ser-23/24 during in vivo myocardial ischemia. Myocardial ischemia decreases intracellular pH resulting in depressed binding of Ca(2+) to TnC and impaired contraction. To determine the pathological relevance of these simultaneous TnI phosphorylations we measured individual TnI Ser-150 (S150D), Ser-23/24 (S23/24D) and combined (S23/24/150D) pseudo-phosphorylation effects on thin filament regulation at acidic pH similar to that in myocardial ischemia. Results demonstrate that while acidic pH decreased thin filament Ca(2+) binding to TnC regardless of TnI composition, TnI S150D attenuated this decrease rendering it similar to non-phosphorylated TnI at normal pH. The dissociation of Ca(2+) from TnC was unaltered by pH such that TnI S150D remained slow, S23/24D remained accelerated and the combined S23/24/150D remained accelerated. This effect of the combined TnI Ser-150 and Ser-23/24 pseudo-phosphorylations to maintain Ca(2+) binding while accelerating Ca(2+) dissociation represents the first post-translational modification of troponin by phosphorylation to both accelerate thin filament deactivation and maintain Ca(2+) sensitive activation. These data suggest that TnI Ser-150 phosphorylation induced attenuation of the pH-dependent decrease in Ca(2+) sensitivity and its combination with Ser-23/24 phosphorylation to maintain accelerated thin filament deactivation may impart an adaptive role to preserve contraction during acidic ischemia pH without slowing relaxation.
Collapse
Affiliation(s)
- Benjamin R Nixon
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Shane D Walton
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Bo Zhang
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Elizabeth A Brundage
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Sean C Little
- 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
| | - Jonathan P Davis
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
| |
Collapse
|
34
|
Abstract
The giant protein titin forms a unique filament network in cardiomyocytes, which engages in both mechanical and signaling functions of the heart. TTN, which encodes titin, is also a major human disease gene. In this review, we cover the roles of cardiac titin in normal and failing hearts, with a special emphasis on the contribution of titin to diastolic stiffness. We provide an update on disease-associated titin mutations in cardiac and skeletal muscles and summarize what is known about the impact of protein-protein interactions on titin properties and functions. We discuss the importance of titin-isoform shifts and titin phosphorylation, as well as titin modifications related to oxidative stress, in adjusting the diastolic stiffness of the healthy and the failing heart. Along the way we distinguish among titin alterations in systolic and in diastolic heart failure and ponder the evidence for titin stiffness as a potential target for pharmacological intervention in heart disease.
Collapse
Affiliation(s)
- Wolfgang A Linke
- From the Department of Cardiovascular Physiology, Ruhr University Bochum, Bochum, Germany
| | | |
Collapse
|
35
|
Liu R, Feng HZ, Jin JP. Physiological contractility of cardiomyocytes in the wall of mouse and rat azygos vein. Am J Physiol Cell Physiol 2014; 306:C697-704. [PMID: 24477237 PMCID: PMC3962596 DOI: 10.1152/ajpcell.00004.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/25/2014] [Indexed: 01/19/2023]
Abstract
We recently demonstrated the abundant presence of cardiomyocytes in the wall of thoracic veins of adult mouse and rat. The highly differentiated morphology and myofilament protein contents of the venous cardiomyocytes suggested contractile functions. Here we further investigated the contractility of mouse and rat azygos venous rings compared with that of atrial strips and ventricular papillary muscle. 5-Bromo-4-chloro-indolyl-galactopyranoside (X-gal) staining of transgenic mouse vessels expressing lacZ under a cloned cardiac troponin T promoter demonstrated that the venous cardiomyocytes are discontinuous from atrial myocardium and aligned in the wall of thoracic veins perpendicular to the vessel axis. Histological sections displayed sarcomeric striations in the venous cardiomyocytes, which indicate an encirclement orientation of myofibrils in the vessel wall. Mechanical studies found that the rings of mouse and rat azygos vein produce strong cardiac type twitch contractions when stimulated with electrical pacing in contrast to the weak and slow smooth muscle contractions induced using 90 mM KCl. The twitch contraction and relaxation of mouse azygos veins further exhibited a cardiac type of β-adrenergic responses. Quantitative comparison showed that the contractions of venous cardiomyocytes are slightly slower than those of atrium muscle but significantly faster than those of ventricular papillary muscle. These novel findings indicate that the cardiomyocytes abundant in the wall of rodent thoracic veins possess fully differentiated cardiac muscle phenotype despite their anatomical and functional segregations from the heart.
Collapse
Affiliation(s)
- Rong Liu
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | | | | |
Collapse
|
36
|
Alibhai FJ, Tsimakouridze EV, Chinnappareddy N, Wright DC, Billia F, O'Sullivan ML, Pyle WG, Sole MJ, Martino TA. Short-term disruption of diurnal rhythms after murine myocardial infarction adversely affects long-term myocardial structure and function. Circ Res 2014; 114:1713-22. [PMID: 24687134 DOI: 10.1161/circresaha.114.302995] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
RATIONALE Patients in intensive care units are disconnected from their natural environment. Synchrony between environmental diurnal rhythms and intracellular circadian rhythms is essential for normal organ biology; disruption causes pathology. Whether disturbing rhythms after myocardial infarction (MI) exacerbates long-term myocardial dysfunction is not known. OBJECTIVE Short-term diurnal rhythm disruption immediately after MI impairs remodeling and adversely affects long-term cardiac structure and function in a murine model. METHODS AND RESULTS Mice were infarcted by left anterior descending coronary artery ligation (MI model) within a 3-hour time window, randomized to either a normal diurnal or disrupted environment for 5 days, and then maintained under normal diurnal conditions. Initial infarct size was identical. Short-term diurnal disruption adversely affected body metabolism and altered early innate immune responses. In the first 5 days, crucial for scar formation, there were significant differences in cardiac myeloperoxidase, cytokines, neutrophil, and macrophage infiltration. Homozygous clock mutant mice exhibited altered infiltration after MI, consistent with circadian mechanisms underlying innate immune responses crucial for scar formation. In the proliferative phase, 1 week after MI, this led to significantly less blood vessel formation in the infarct region of disrupted mice; by day 14, echocardiography showed increased left ventricular dilation and infarct expansion. These differences continued to evolve with worse cardiac structure and function by 8 weeks after MI. CONCLUSIONS Diurnal rhythm disruption immediately after MI impaired healing and exacerbated maladaptive cardiac remodeling. These preclinical findings suggest that disrupted diurnal rhythms such as found in modern intensive care unit environments may adversely affect long-term patient outcome.
Collapse
Affiliation(s)
- Faisal J Alibhai
- From the Cardiovascular Research Group, Department of Biomedical Sciences (F.J.A., E.V.T., N.C., W.G.P., T.A.M.), Department of Human Health and Nutritional Sciences (D.C.W.), and Department of Clinical Studies (M.L.O.), University of Guelph, Guelph, Ontario, Canada; and Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (F.B., M.J.S.)
| | - Elena V Tsimakouridze
- From the Cardiovascular Research Group, Department of Biomedical Sciences (F.J.A., E.V.T., N.C., W.G.P., T.A.M.), Department of Human Health and Nutritional Sciences (D.C.W.), and Department of Clinical Studies (M.L.O.), University of Guelph, Guelph, Ontario, Canada; and Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (F.B., M.J.S.)
| | - Nirmala Chinnappareddy
- From the Cardiovascular Research Group, Department of Biomedical Sciences (F.J.A., E.V.T., N.C., W.G.P., T.A.M.), Department of Human Health and Nutritional Sciences (D.C.W.), and Department of Clinical Studies (M.L.O.), University of Guelph, Guelph, Ontario, Canada; and Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (F.B., M.J.S.)
| | - David C Wright
- From the Cardiovascular Research Group, Department of Biomedical Sciences (F.J.A., E.V.T., N.C., W.G.P., T.A.M.), Department of Human Health and Nutritional Sciences (D.C.W.), and Department of Clinical Studies (M.L.O.), University of Guelph, Guelph, Ontario, Canada; and Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (F.B., M.J.S.)
| | - Filio Billia
- From the Cardiovascular Research Group, Department of Biomedical Sciences (F.J.A., E.V.T., N.C., W.G.P., T.A.M.), Department of Human Health and Nutritional Sciences (D.C.W.), and Department of Clinical Studies (M.L.O.), University of Guelph, Guelph, Ontario, Canada; and Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (F.B., M.J.S.)
| | - M Lynne O'Sullivan
- From the Cardiovascular Research Group, Department of Biomedical Sciences (F.J.A., E.V.T., N.C., W.G.P., T.A.M.), Department of Human Health and Nutritional Sciences (D.C.W.), and Department of Clinical Studies (M.L.O.), University of Guelph, Guelph, Ontario, Canada; and Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (F.B., M.J.S.)
| | - W Glen Pyle
- From the Cardiovascular Research Group, Department of Biomedical Sciences (F.J.A., E.V.T., N.C., W.G.P., T.A.M.), Department of Human Health and Nutritional Sciences (D.C.W.), and Department of Clinical Studies (M.L.O.), University of Guelph, Guelph, Ontario, Canada; and Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (F.B., M.J.S.)
| | - Michael J Sole
- From the Cardiovascular Research Group, Department of Biomedical Sciences (F.J.A., E.V.T., N.C., W.G.P., T.A.M.), Department of Human Health and Nutritional Sciences (D.C.W.), and Department of Clinical Studies (M.L.O.), University of Guelph, Guelph, Ontario, Canada; and Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (F.B., M.J.S.)
| | - Tami A Martino
- From the Cardiovascular Research Group, Department of Biomedical Sciences (F.J.A., E.V.T., N.C., W.G.P., T.A.M.), Department of Human Health and Nutritional Sciences (D.C.W.), and Department of Clinical Studies (M.L.O.), University of Guelph, Guelph, Ontario, Canada; and Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada (F.B., M.J.S.).
| |
Collapse
|
37
|
Milani-Nejad N, Janssen PML. Small and large animal models in cardiac contraction research: advantages and disadvantages. Pharmacol Ther 2014; 141:235-49. [PMID: 24140081 PMCID: PMC3947198 DOI: 10.1016/j.pharmthera.2013.10.007] [Citation(s) in RCA: 308] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 08/15/2013] [Indexed: 12/22/2022]
Abstract
The mammalian heart is responsible for not only pumping blood throughout the body but also adjusting this pumping activity quickly depending upon sudden changes in the metabolic demands of the body. For the most part, the human heart is capable of performing its duties without complications; however, throughout many decades of use, at some point this system encounters problems. Research into the heart's activities during healthy states and during adverse impacts that occur in disease states is necessary in order to strategize novel treatment options to ultimately prolong and improve patients' lives. Animal models are an important aspect of cardiac research where a variety of cardiac processes and therapeutic targets can be studied. However, there are differences between the heart of a human being and an animal and depending on the specific animal, these differences can become more pronounced and in certain cases limiting. There is no ideal animal model available for cardiac research, the use of each animal model is accompanied with its own set of advantages and disadvantages. In this review, we will discuss these advantages and disadvantages of commonly used laboratory animals including mouse, rat, rabbit, canine, swine, and sheep. Since the goal of cardiac research is to enhance our understanding of human health and disease and help improve clinical outcomes, we will also discuss the role of human cardiac tissue in cardiac research. This review will focus on the cardiac ventricular contractile and relaxation kinetics of humans and animal models in order to illustrate these differences.
Collapse
Affiliation(s)
- Nima Milani-Nejad
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA.
| |
Collapse
|
38
|
Balogh A, Santer D, Pásztor ET, Tóth A, Czuriga D, Podesser BK, Trescher K, Jaquet K, Erdodi F, Edes I, Papp Z. Myofilament protein carbonylation contributes to the contractile dysfunction in the infarcted LV region of mouse hearts. Cardiovasc Res 2013; 101:108-19. [PMID: 24127233 DOI: 10.1093/cvr/cvt236] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS The region-specific mechanical function of left ventricular (LV) murine cardiomyocytes and the role of phosphorylation and oxidative modifications of myofilament proteins were investigated in the process of post-myocardial infarction (MI) remodelling 10 weeks after ligation of the left anterior descending (LAD) coronary artery. METHODS AND RESULTS Permeabilized murine cardiomyocytes from the remaining anterior and a remote non-infarcted inferior LV area were compared with those of non-infarcted age-matched controls. Myofilament phosphorylation, sulfhydryl (SH) oxidation, and carbonylation were also assayed. Ca(2+) sensitivity of force production was significantly lower in the anterior wall (pCa50: 5.81 ± 0.03, means ± SEM, at 2.3 µm sarcomere length) than that in the controls (pCa50: 5.91 ± 0.02) or in the MI inferior area (pCa50: 5.88 ± 0.02). The level of troponin I phosphorylation was lower and that of myofilament protein SH oxidation was higher in the anterior location relative to controls, but these changes did not explain the differences in Ca(2+) sensitivities. On the other hand, significantly higher carbonylation levels, [e.g. in myosin heavy chain (MHC) and actin] were observed in the MI anterior wall [carbonylation index (CI), CIMHC: 2.06 ± 0.46, CIactin: 1.46 ± 0.18] than in the controls (CI: 1). In vitro Fenton-based myofilament carbonylation in the control cardiomyocytes also decreased the Ca(2+) sensitivity of force production irrespective of the phosphorylation status of the myofilaments. Furthermore, the Ca(2+) sensitivity correlated strongly with myofilament carbonylation levels in all investigated samples. CONCLUSION Post-MI myocardial remodelling involves increased myofibrillar protein carbonylation and decreased Ca(2+) sensitivity of force production, leading potentially to contractile dysfunction in the remaining cardiomyocytes of the infarcted area.
Collapse
Affiliation(s)
- Agnes Balogh
- Division of Clinical Physiology, Research Center for Molecular Medicine, Institute of Cardiology, Faculty of Medicine, Medical and Health Science Center, University of Debrecen, Móricz Zs. krt. 22, Debrecen H-4032, Hungary
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Posttranslational modifications of cardiac troponin T: An overview. J Mol Cell Cardiol 2013; 63:47-56. [DOI: 10.1016/j.yjmcc.2013.07.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 06/18/2013] [Accepted: 07/08/2013] [Indexed: 12/22/2022]
|
40
|
Wang H, Wang L, Song L, Zhang YW, Ye J, Xu RX, Shi N, Meng XM. TNNI3K is a novel mediator of myofilament function and phosphorylates cardiac troponin I. Braz J Med Biol Res 2013; 46:128-37. [PMID: 23369981 PMCID: PMC3854359 DOI: 10.1590/1414-431x20122515] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 10/22/2012] [Indexed: 11/21/2022] Open
Abstract
The phosphorylation of cardiac troponin I (cTnI) plays an important role in the contractile dysfunction associated with heart failure. Human cardiac troponin I-interacting kinase (TNNI3K) is a novel cardiac-specific functional kinase that can bind to cTnI in a yeast two-hybrid screen. The purpose of this study was to investigate whether TNNI3K can phosphorylate cTnI at specific sites and to examine whether the phosphorylation of cTnI caused by TNNI3K can regulate cardiac myofilament contractile function. Co-immunoprecipitation was performed to confirm that TNNI3K could interact with cTnI. Kinase assays further indicated that TNNI3K did not phosphorylate cTnI at Ser23/24 and Ser44, but directly phosphorylated Ser43 and Thr143 in vitro. The results obtained for adult rat cardiomyocytes also indicated that enhanced phosphorylation of cTnI at Ser43 and Thr143 correlated with rTNNI3K (rat TNNI3K) overexpression, and phosphorylation was reduced when rTNNI3K was knocked down. To determine the contractile function modulated by TNNI3K-mediated phosphorylation of cTnI, cardiomyocyte contraction was studied in adult rat ventricular myocytes. The contraction of cardiomyocytes increased with rTNNI3K overexpression and decreased with rTNNI3K knockdown. We conclude that TNNI3K may be a novel mediator of cTnI phosphorylation and contribute to the regulation of cardiac myofilament contraction function.
Collapse
Affiliation(s)
- Hui Wang
- Chinese Academy of Medical Sciences and Peking Union Medical College, Core Laboratory, Fu Wai Hospital and Cardiovascular Institute, Beijing, China
| | | | | | | | | | | | | | | |
Collapse
|
41
|
A kinase interacting protein (AKIP1) is a key regulator of cardiac stress. Proc Natl Acad Sci U S A 2013; 110:E387-96. [PMID: 23319652 DOI: 10.1073/pnas.1221670110] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
cAMP-dependent protein kinase (PKA) regulates a myriad of functions in the heart, including cardiac contractility, myocardial metabolism,and gene expression. However, a molecular integrator of the PKA response in the heart is unknown. Here, we show that the PKA adaptor A-kinase interacting protein 1 (AKIP1) is up-regulated in cardiac myocytes in response to oxidant stress. Mice with cardiac gene transfer of AKIP1 have enhanced protection to ischemic stress. We hypothesized that this adaptation to stress was mitochondrial dependent. AKIP1 interacted with the mitochondrial localized apoptosis inducing factor (AIF) under both normal and oxidant stress. When cardiac myocytes or whole hearts are exposed to oxidant and ischemic stress, levels of both AKIP1 and AIF were enhanced. AKIP1 is preferentially localized to interfibrillary mitochondria and up-regulated in this cardiac mitochondrial subpopulation on ischemic injury. Mitochondria isolated from AKIP1 gene transferred hearts showed increased mitochondrial localization of AKIP1, decreased reactive oxygen species generation, enhanced calcium tolerance, decreased mitochondrial cytochrome C release,and enhance phosphorylation of mitochondrial PKA substrates on ischemic stress. These observations highlight AKIP1 as a critical molecular regulator and a therapeutic control point for stress adaptation in the heart.
Collapse
|
42
|
Hamdani N, Bishu KG, von Frieling-Salewsky M, Redfield MM, Linke WA. Deranged myofilament phosphorylation and function in experimental heart failure with preserved ejection fraction. Cardiovasc Res 2012; 97:464-71. [PMID: 23213108 DOI: 10.1093/cvr/cvs353] [Citation(s) in RCA: 173] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
AIMS Heart failure (HF) with preserved ejection fraction (HFpEF) is a major cause of morbidity and mortality. Key alterations in HFpEF include increased left ventricular (LV) stiffness and abnormal relaxation. We hypothesized that myofilament protein phosphorylation and function are deranged in experimental HFpEF vs. normal myocardium. Such alterations may involve the giant elastic protein titin, which contributes decisively to LV stiffness. METHODS AND RESULTS LV tissue samples were procured from normal dogs (CTRL) and old dogs with hypertension-induced LV hypertrophy and diastolic dysfunction (OHT/HFpEF). We quantified the expression and phosphorylation of myofilament proteins, including all-titin and site-specific titin phosphorylation, and assessed the expression/activity of major protein kinases (PKs) and phosphatases (PPs), myofilament calcium sensitivity (pCa(50)), and passive tension (F(passive)) of isolated permeabilized cardiomyocytes. In OHT vs. CTRL hearts, protein kinase-G (PKG) activity was decreased, whereas PKCα activity and PP1/PP2a expression were increased. Cardiac MyBPC, TnT, TnI and MLC2 were less phosphorylated and pCa(50) was increased in OHT vs. CTRL. The titin N2BA (compliant) to N2B (stiff) isoform-expression ratio was lowered in OHT. Hypophosphorylation in OHT was detected for all-titin and at serines S4010/S4099 within titin-N2Bus, whereas S11878 within proline, glutamate, valine, and lysine (PEVK)-titin was hyperphosphorylated. Cardiomyocyte F(passive) was elevated in OHT, but could be normalized by PKG or PKA, but not PKCα, treatment. CONCLUSIONS This patient-mimicking HFpEF model is characterized by titin stiffening through altered isoform composition and phosphorylation, both contributing to increased LV stiffness. Hypophosphorylation of myofilament proteins and increased calcium sensitivity suggest that functional impairment at the sarcomere level may be an early event in HFpEF.
Collapse
Affiliation(s)
- Nazha Hamdani
- Department of Cardiovascular Physiology, Ruhr University, MA 3/56, D-44780 Bochum, Germany
| | | | | | | | | |
Collapse
|
43
|
Kang S, Liu Y, Sun D, Zhou C, Liu A, Xu C, Hao Y, Li D, Yan C, Sun H. Chronic activation of the G protein-coupled receptor 30 with agonist G-1 attenuates heart failure. PLoS One 2012; 7:e48185. [PMID: 23110207 PMCID: PMC3482180 DOI: 10.1371/journal.pone.0048185] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 09/25/2012] [Indexed: 11/18/2022] Open
Abstract
G protein-coupled receptor (GPR) 30 is a novel estrogen receptor. Recent studies suggest that activation of the GPR30 confers rapid cardioprotection in isolated rat heart. It is unknown whether chronic activation of GPR30 is beneficial or not for heart failure. In this study we investigated the cardiac effect of sustained activation or inhibition of GPR30. Female Sprague–Dawley rats were divided into 7 groups #2Q1: sham surgery (Sham), bilateral ovariectomy (OVX), OVX+estrogen (E2), OVX+isoproterenol (ISO), OVX+ISO+G-1, OVX+ISO+E2+G15, OVX+ISO+E2. ISO (85 mg/kg×17 day, sc) was given to make the heart failure models. G-1(120 µg/kg·d×14 day) was used to activate GPR30 and G15 (190 µg/kg·d×14 day) was used to inhibit GPR30. Concentration of brain natriuretic peptide in serum, masson staining in isolated heart, contractile function and the expression of β1 and β2- adrenergic receptor (AR) of ventricular myocytes were also determined. Our data showed that ISO treatment led to heart failure in OVX rats. G-1 or E2 treatment decreased concentration of brain natriuretic peptide, reduced cardiac fibrosis, and enhanced contraction of the heart. Combined treatment with β1 (CGP20712A) and β2-AR (ICI118551) antagonist abolished the improvement of myocardial function induced by G-1. We also found that chronic treatment with G-1 normalized the expression of β1-AR and increased the expression of β2-AR. Our results indicate that chronic activation of the GPR30 with its agonist G-1 attenuates heart failure by normalizing the expression of β1-AR and increasing the expression of β2-AR.
Collapse
Affiliation(s)
- Shoulei Kang
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221002, China
| | - Ying Liu
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221002, China
| | - Di Sun
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221002, China
| | - Chunle Zhou
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221002, China
| | - Aiying Liu
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221002, China
| | - Chuanying Xu
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221002, China
| | - Yanling Hao
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221002, China
| | - Dongye Li
- Institute of Cardiovascular Disease Research, Xuzhou Medical College Affiliated Hospital, Xuzhou, 221002, China
- * E-mail: (DL); (HS)
| | - Changdong Yan
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221002, China
| | - Hong Sun
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221002, China
- * E-mail: (DL); (HS)
| |
Collapse
|
44
|
Abstract
In response to injury or stress, the adult heart undergoes maladaptive changes, collectively defined as pathological cardiac remodeling. Here, we focus on the role of A-kinase anchoring proteins (AKAPs) in 3 main areas associated with cardiac remodeling and the progression of heart failure: excitation-contraction coupling, sarcomeric regulation, and induction of pathological hypertrophy. AKAPs are a diverse family of scaffold proteins that form multiprotein complexes, integrating cAMP signaling with protein kinases, phosphatases, and other effector proteins. Many AKAPs have been characterized in the heart, where they play a critical role in modulating cardiac function.
Collapse
|
45
|
van der Velden J, Merkus D, de Beer V, Hamdani N, Linke WA, Boontje NM, Stienen GJM, Duncker DJ. Transmural heterogeneity of myofilament function and sarcomeric protein phosphorylation in remodeled myocardium of pigs with a recent myocardial infarction. Front Physiol 2011; 2:83. [PMID: 22131977 PMCID: PMC3223384 DOI: 10.3389/fphys.2011.00083] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 10/28/2011] [Indexed: 02/05/2023] Open
Abstract
Aim: Transmural differences in sarcomeric protein composition and function across the left ventricular (LV) wall have been reported. We studied in pigs sarcomeric function and protein phosphorylation in subepicardial (EPI) and subendocardial (ENDO) layers of remote LV myocardium after myocardial infarction (MI), induced by left circumflex coronary artery ligation. Methods: EPI and ENDO samples were taken 3 weeks after sham surgery (n = 12) or induction of MI (n = 12) at baseline (BL) and during β-adrenergic receptor (βAR) stimulation with dobutamine. Isometric force was measured in single cardiomyocytes at various [Ca2+] and 2.2 μm sarcomere length. Results: In sham hearts, no significant transmural differences were observed in myofilament function or protein phosphorylation. Myofilament Ca2+-sensitivity was significantly higher in both EPI and ENDO of MI compared to sham hearts. Maximal force was significantly reduced in MI compared to sham, but solely in ENDO cells. A higher passive force was observed in MI hearts, but only in EPI cells. The proportion of stiff N2B isoform was higher in EPI than in ENDO in both sham and MI hearts, and a trend toward increased N2B-proportion appeared in MI EPI, but not MI Endo. Analysis of myofilament protein phosphorylation did not reveal significant transmural differences in phosphorylation of myosin binding protein C, desmin, troponin T, troponin I (cTnI), and myosin light chain 2 (MLC-2) both at BL and during βAR stimulation with dobutamine infusion. A significant increase in MLC-2 phosphorylation was observed during dobutamine only in sham. In addition, the increase in cTnI phosphorylation upon dobutamine was twofold lower in MI than in sham. Conclusion: Myofilament dysfunction is present in both EPI and ENDO in post-MI remodeled myocardium, but shows a high degree of qualitative heterogeneity across the LV wall. These heterogeneous transmural changes in sarcomeric properties likely contribute differently to systolic vs. diastolic global LV dysfunction after MI.
Collapse
Affiliation(s)
- Jolanda van der Velden
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Left ventricular remodeling in swine after myocardial infarction: a transcriptional genomics approach. Basic Res Cardiol 2011; 106:1269-81. [PMID: 22057716 PMCID: PMC3228945 DOI: 10.1007/s00395-011-0229-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/04/2011] [Accepted: 10/20/2011] [Indexed: 01/06/2023]
Abstract
Despite the apparent appropriateness of left ventricular (LV) remodeling following myocardial infarction (MI), it poses an independent risk factor for development of heart failure. There is a paucity of studies into the molecular mechanisms of LV remodeling in large animal species. We took an unbiased molecular approach to identify candidate transcription factors (TFs) mediating the genetic reprogramming involved in post-MI LV remodeling in swine. Left ventricular tissue was collected from remote, non-infarcted myocardium, 3 weeks after MI-induction or sham-surgery. Microarray analysis identified 285 upregulated and 278 downregulated genes (FDR < 0.05). Of these differentially expressed genes, the promoter regions of the human homologs were searched for common TF binding sites (TFBS). Eighteen TFBS were overrepresented >two-fold (p < 0.01) in upregulated and 13 in downregulated genes. Left ventricular nuclear protein extracts were assayed for DNA-binding activity by protein/DNA array. Out of 345 DNA probes, 30 showed signal intensity changes >two-fold. Five TFs were identified in both TFBS and protein/DNA array analyses, which showed matching changes for COUP-TFII and glucocorticoid receptor (GR) only. Treatment of swine with the GR antagonist mifepristone after MI reduced the post-MI increase in LV mass, but LV dilation remained unaffected. Thus, using an unbiased approach to study post-MI LV remodeling in a physiologically relevant large animal model, we identified COUP-TFII and GR as potential key mediators of post-MI remodeling.
Collapse
|
47
|
Hudson B, Hidalgo C, Saripalli C, Granzier H. Hyperphosphorylation of mouse cardiac titin contributes to transverse aortic constriction-induced diastolic dysfunction. Circ Res 2011; 109:858-66. [PMID: 21835910 DOI: 10.1161/circresaha.111.246819] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RATIONALE Mechanisms underlying diastolic dysfunction need to be better understood. OBJECTIVE To study the role of titin in diastolic dysfunction using a mouse model of experimental heart failure induced by transverse aortic constriction. METHODS AND RESULTS Eight weeks after transverse aortic constriction surgery, mice were divided into heart failure (HF) and congestive heart failure (CHF) groups. Mechanical studies on skinned left ventricle myocardium measured total and titin-based and extracellular matrix-based passive stiffness. Total passive stiffness was increased in both HF and CHF mice, and this was attributable to increases in both extracellular matrix-based and titin-based passive stiffness, with titin being dominant. Protein expression and titin exon microarray analysis revealed increased expression of the more compliant N2BA isoform at the expense of the stiff N2B isoform in HF and CHF mice. These changes are predicted to lower titin-based stiffness. Because the stiffness of titin is also sensitive to titin phosphorylation by protein kinase A and protein kinase C, back phosphorylation and Western blot assays with novel phospho-specific antibodies were performed. HF and CHF mice showed hyperphosphorylation of protein kinase A sites and the proline glutamate valine lysine (PEVK) S26 protein kinase C sites, but hypophosphorylation of the PEVK S170 protein kinase C site. Protein phosphatase I abolished differences in phosphorylation levels and normalized titin-based passive stiffness levels between control and HF myocardium. CONCLUSION Transverse aortic constriction-induced HF results in increased extracellular matrix-based and titin-based passive stiffness. Changes in titin splicing occur, which lower passive stiffness, but this effect is offset by hyperphosphorylation of residues in titin spring elements, particularly of PEVK S26. Thus, complex changes in titin occur that combined are a major factor in the increased passive myocardial stiffness in HF.
Collapse
Affiliation(s)
- Bryan Hudson
- Department of Physiology, University of Arizona, Tucson, USA
| | | | | | | |
Collapse
|
48
|
Diastolic myofilament dysfunction in the failing human heart. Pflugers Arch 2011; 462:155-63. [PMID: 21487693 PMCID: PMC3114087 DOI: 10.1007/s00424-011-0960-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 03/23/2011] [Accepted: 03/24/2011] [Indexed: 01/06/2023]
Abstract
In recent years, it has become evident that heart failure is not solely due to reduced contractile performance of the heart muscle as impaired relaxation is evident in almost all heart failure patients. In more than half of all heart failure patients, diastolic dysfunction is the major cardiac deficit. These heart failure patients have normal (or preserved) left ventricular ejection fraction, but impaired diastolic function evident from increased left ventricular end-diastolic pressure. Perturbations at the cellular level which cause impaired relaxation of the heart muscle involve changes in Ca(2+)-handling proteins, extracellular matrix components, and myofilament properties. The present review discusses the deficits in myofilament function observed in human heart failure and the most likely underlying causal protein changes. Moreover, the consequences of impaired myofilament function for in vivo diastolic dysfunction are discussed taking into account the reported changes in Ca(2+) handling.
Collapse
|
49
|
King NMP, Methawasin M, Nedrud J, Harrell N, Chung CS, Helmes M, Granzier H. Mouse intact cardiac myocyte mechanics: cross-bridge and titin-based stress in unactivated cells. ACTA ACUST UNITED AC 2011; 137:81-91. [PMID: 21187335 PMCID: PMC3010058 DOI: 10.1085/jgp.201010499] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A carbon fiber-based cell attachment and force measurement system was used to measure the diastolic stress-sarcomere length (SL) relation of mouse intact cardiomyocytes, before and after the addition of actomyosin inhibitors (2,3-butanedione monoxime [BDM] or blebbistatin). Stress was measured during the diastolic interval of twitching myocytes that were stretched at 100% base length/second. Diastolic stress increased close to linear from 0 at SL 1.85 µm to 4.2 mN/mm(2) at SL 2.1 µm. The actomyosin inhibitors BDM and blebbistatin significantly lowered diastolic stress by ∼1.5 mN/mm(2) (at SL 2.1 µm, ∼30% of total), suggesting that during diastole actomyosin interaction is not fully switched off. To test this further, calcium sensitivity of skinned myocytes was studied under conditions that simulate diastole: 37°C, presence of Dextran T500 to compress the myofilament lattice to the physiological level, and [Ca(2+)] from below to above 100 nM. Mean active stress was significantly increased at [Ca(2+)] > 55 nM (pCa 7.25) and was ∼0.7 mN/mm(2) at 100 nM [Ca(2+)] (pCa 7.0) and ∼1.3 mN/mm(2) at 175 nM Ca(2+) (pCa 6.75). Inhibiting active stress in intact cells attached to carbon fibers at their resting SL and stretching the cells while first measuring restoring stress (pushing outward) and then passive stress (pulling inward) made it possible to determine the passive cell's mechanical slack SL as ∼1.95 µm and the restoring stiffness and passive stiffness of the cells around the slack SL each as ∼17 mN/mm(2)/µm/SL. Comparison between the results of intact and skinned cells shows that titin is the main contributor to restoring stress and passive stress of intact cells, but that under physiological conditions, calcium sensitivity is sufficiently high for actomyosin interaction to contribute to diastolic stress. These findings are relevant for understanding diastolic function and for future studies of diastolic heart failure.
Collapse
Affiliation(s)
- Nicholas M P King
- Department of Physiology and Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85724, USA. granzier@email.arizona.edu
| | | | | | | | | | | | | |
Collapse
|
50
|
Dubois E, Fertin M, Burdese J, Amouyel P, Bauters C, Pinet F. Cardiovascular proteomics: translational studies to develop novel biomarkers in heart failure and left ventricular remodeling. Proteomics Clin Appl 2011; 5:57-66. [PMID: 21246740 DOI: 10.1002/prca.201000056] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 10/18/2010] [Accepted: 11/10/2010] [Indexed: 02/06/2023]
Abstract
Heart failure (HF) remains a severe disease with a poor prognosis. HF biomarkers may include demographic features, cardiac imaging, or genetic polymorphisms but this term is commonly applied to circulating serum or plasma analytes. Biomarkers may have at least three clinical uses in the context of HF: diagnosis, risk stratification, and guidance in the selection of therapy. Proteomic studies on HF biomarkers can be designed as case/control using clinical endpoints; alternatively, left ventricular remodeling can be used as a surrogate endpoint. The type of samples (tissue, cells, serum or plasma) used for proteomic analysis is a key factor in the research of biomarkers. Since the final aim is the discovery of circulating biomarkers, and since plasma and serum samples are easily accessible, proteomic analysis is frequently used for blood samples. However, standardization of sampling and access to low-abundance proteins remains problematic. Although, proteomics is playing a major role in the discovery phase of biomarkers, validation in independent populations is necessary by using more specific methods. The knowledge of new HF biomarkers may allow a more personalized medicine in the future.
Collapse
|