1
|
Soetkamp D, Gallet R, Parker SJ, Holewinski R, Venkatraman V, Peck K, Goldhaber JI, Marbán E, Van Eyk JE. Myofilament Phosphorylation in Stem Cell Treated Diastolic Heart Failure. Circ Res 2021; 129:1125-1140. [PMID: 34641704 DOI: 10.1161/circresaha.119.316311] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
RATIONALE Phosphorylation of sarcomeric proteins has been implicated in heart failure with preserved ejection fraction (HFpEF); such changes may contribute to diastolic dysfunction by altering contractility, cardiac stiffness, Ca2+-sensitivity, and mechanosensing. Treatment with cardiosphere-derived cells (CDCs) restores normal diastolic function, attenuates fibrosis and inflammation, and improves survival in a rat HFpEF model. OBJECTIVE Phosphorylation changes that underlie HFpEF and those reversed by CDC therapy, with a focus on the sarcomeric subproteome were analyzed. METHODS AND RESULTS Dahl salt-sensitive rats fed a high-salt diet, with echocardiographically verified diastolic dysfunction, were randomly assigned to either intracoronary CDCs or placebo. Dahl salt-sensitive rats receiving low salt diet served as controls. Protein and phosphorylated Ser, Thr, and Tyr residues from left ventricular tissue were quantified by mass spectrometry. HFpEF hearts exhibited extensive hyperphosphorylation with 98% of the 529 significantly changed phospho-sites increased compared with control. Of those, 39% were located within the sarcomeric subproteome, with a large group of proteins located or associated with the Z-disk. CDC treatment partially reverted the hyperphosphorylation, with 85% of the significantly altered 76 residues hypophosphorylated. Bioinformatic upstream analysis of the differentially phosphorylated protein residues revealed PKC as the dominant putative regulatory kinase. PKC isoform analysis indicated increases in PKC α, β, and δ concentration, whereas CDC treatment led to a reversion of PKCβ. Use of PKC isoform specific inhibition and overexpression of various PKC isoforms strongly suggests that PKCβ is the dominant kinase involved in hyperphosphorylation in HFpEF and is altered with CDC treatment. CONCLUSIONS Increased protein phosphorylation at the Z-disk is associated with diastolic dysfunction, with PKC isoforms driving most quantified phosphorylation changes. Because CDCs reverse the key abnormalities in HFpEF and selectively reverse PKCβ upregulation, PKCβ merits being classified as a potential therapeutic target in HFpEF, a disease notoriously refractory to medical intervention.
Collapse
Affiliation(s)
- Daniel Soetkamp
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Romain Gallet
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Sarah J Parker
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | | | | | - Kiel Peck
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | | | - Eduardo Marbán
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | | |
Collapse
|
2
|
Sheng JJ, Feng HZ, Pinto JR, Wei H, Jin JP. Increases of desmin and α-actinin in mouse cardiac myofibrils as a response to diastolic dysfunction. J Mol Cell Cardiol 2015; 99:218-229. [PMID: 26529187 DOI: 10.1016/j.yjmcc.2015.10.035] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 12/20/2022]
Abstract
Up-regulation of desmin has been reported in cardiac hypertrophy and failure but the pathophysiological cause and significance remain to be investigated. By examining genetically modified mouse models representative for diastolic or systolic heart failure, we found significantly increased levels of desmin and α-actinin in the myofibrils of hearts with impaired diastolic function but not hearts with weakened systolic function. The increased desmin and α-actinin are mainly found in myofibrils at the Z-disks. Two weeks of transverse aortic constriction (TAC) induced increases of desmin and α-actinin in mouse hearts of occult diastolic failure but not in wild type or transgenic mouse hearts with mildly lowered systolic function or with increased diastolic function. The chronic or TAC-induced increase of desmin showed no proportional increase in phosphorylation, implicating an up-regulated expression rather than a decreased protein turnover. The data demonstrate a novel early response specifically to diastolic heart failure, indicating a function of the Z-disk in the challenging clinical condition of heart failure with preserved ejection fraction (HFpEF).
Collapse
Affiliation(s)
- Juan-Juan Sheng
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Han-Zhong Feng
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Jose R Pinto
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Hongguang Wei
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - J-P Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA.
| |
Collapse
|
3
|
Peche VS, Holak TA, Burgute BD, Kosmas K, Kale SP, Wunderlich FT, Elhamine F, Stehle R, Pfitzer G, Nohroudi K, Addicks K, Stöckigt F, Schrickel JW, Gallinger J, Schleicher M, Noegel AA. Ablation of cyclase-associated protein 2 (CAP2) leads to cardiomyopathy. Cell Mol Life Sci 2013; 70:527-43. [PMID: 22945801 PMCID: PMC11113306 DOI: 10.1007/s00018-012-1142-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 08/01/2012] [Accepted: 08/14/2012] [Indexed: 12/24/2022]
Abstract
Cyclase-associated proteins are highly conserved proteins that have a role in the regulation of actin dynamics. Higher eukaryotes have two isoforms, CAP1 and CAP2. To study the in vivo function of CAP2, we generated mice in which the CAP2 gene was inactivated by a gene-trap approach. Mutant mice showed a decrease in body weight and had a decreased survival rate. Further, they developed a severe cardiac defect marked by dilated cardiomyopathy (DCM) associated with drastic reduction in basal heart rate and prolongations in atrial and ventricular conduction times. Moreover, CAP2-deficient myofibrils exhibited reduced cooperativity of calcium-regulated force development. At the microscopic level, we observed disarrayed sarcomeres with development of fibrosis. We analyzed CAP2's role in actin assembly and found that it sequesters G-actin and efficiently fragments filaments. This activity resides completely in its WASP homology domain. Thus CAP2 is an essential component of the myocardial sarcomere and is essential for physiological functioning of the cardiac system, and a deficiency leads to DCM and various cardiac defects.
Collapse
Affiliation(s)
- Vivek S. Peche
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Tad A. Holak
- Max-Planck-Institute of Biochemistry, 82152 Martinsried, Germany
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland
| | - Bhagyashri D. Burgute
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Kosmas Kosmas
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
| | - Sushant P. Kale
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, IL USA
| | - F. Thomas Wunderlich
- Center for Molecular Medicine Cologne (CMMC), Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Max-Planck-Institute of Neurological Research, Cologne, Germany
| | - Fatiha Elhamine
- Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Robert Stehle
- Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Gabriele Pfitzer
- Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Klaus Nohroudi
- Institute of Anatomy I, University of Cologne, Cologne, Germany
| | - Klaus Addicks
- Institute of Anatomy I, University of Cologne, Cologne, Germany
| | - Florian Stöckigt
- Department of Medicine-Cardiology, University of Bonn, Bonn, Germany
| | - Jan W. Schrickel
- Department of Medicine-Cardiology, University of Bonn, Bonn, Germany
| | - Julia Gallinger
- Institute for Anatomy and Cell Biology, Ludwig-Maximilians University, 80336 Munich, Germany
| | - Michael Schleicher
- Institute for Anatomy and Cell Biology, Ludwig-Maximilians University, 80336 Munich, Germany
| | - Angelika A. Noegel
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| |
Collapse
|
4
|
Loss of T-tubules and other changes to surface topography in ventricular myocytes from failing human and rat heart. Proc Natl Acad Sci U S A 2009; 106:6854-9. [PMID: 19342485 DOI: 10.1073/pnas.0809777106] [Citation(s) in RCA: 285] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
T-tubular invaginations of the sarcolemma of ventricular cardiomyocytes contain junctional structures functionally coupling L-type calcium channels to the sarcoplasmic reticulum calcium-release channels (the ryanodine receptors), and therefore their configuration controls the gain of calcium-induced calcium release (CICR). Studies primarily in rodent myocardium have shown the importance of T-tubular structures for calcium transient kinetics and have linked T-tubule disruption to delayed CICR. However, there is disagreement as to the nature of T-tubule changes in human heart failure. We studied isolated ventricular myocytes from patients with ischemic heart disease, idiopathic dilated cardiomyopathy, and hypertrophic obstructive cardiomyopathy and determined T-tubule structure with either the fluorescent membrane dye di-8-ANNEPs or the scanning ion conductance microscope (SICM). The SICM uses a scanning pipette to produce a topographic representation of the surface of the live cell by a non-optical method. We have also compared ventricular myocytes from a rat model of chronic heart failure after myocardial infarction. T-tubule loss, shown by both ANNEPs staining and SICM imaging, was pronounced in human myocytes from all etiologies of disease. SICM imaging showed additional changes in surface structure, with flattening and loss of Z-groove definition common to all etiologies. Rat myocytes from the chronic heart failure model also showed both T-tubule and Z-groove loss, as well as increased spark frequency and greater spark amplitude. This study confirms the loss of T-tubules as part of the phenotypic change in the failing human myocyte, but it also shows that this is part of a wider spectrum of alterations in surface morphology.
Collapse
|
5
|
Kostek MC, Chen YW, Cuthbertson DJ, Shi R, Fedele MJ, Esser KA, Rennie MJ. Gene expression responses over 24 h to lengthening and shortening contractions in human muscle: major changes in CSRP3, MUSTN1, SIX1, and FBXO32. Physiol Genomics 2007; 31:42-52. [PMID: 17519359 DOI: 10.1152/physiolgenomics.00151.2006] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Resistance training using lengthening (eccentric) contractions induces greater increases in muscle size than shortening (concentric) contractions, but the underlying molecular mechanisms are not clear. Using temporal expression profiling, we compared changes in gene expression within 24 h of an acute bout of each type of contractions conducted simultaneously in the quadriceps of different legs. Five healthy young men performed shortening contractions with one leg while the contralateral leg performed lengthening contractions. Biopsies were taken from both legs before exercise and 3, 6, and 24 h afterwards, in the fed state. Expression profiling ( n = 3) was performed using a custom-made Affymetrix MuscleChip containing probe sets of ∼3,300 known genes and expressed sequence tags expressed in skeletal muscle. We identified 51 transcripts differentially regulated between the two exercise modes. Using unsupervised hierarchical clustering, we identified four distinct clusters, three of which corresponded to unique functional categories (protein synthesis, stress response/early growth, and sarcolemmal structure). Using quantitative RT-PCR ( n = 5), we verified expression changes (lengthening/shortening) in SIX1 (3 h, −1.9-fold, P < 0.001), CSRP3 (6 h, 2.9-fold, P < 0.05), and MUSTN1 (24 h, 4.3-fold, P < 0.05). We examined whether FBXO32/atrogin-1/MAFbx, a known regulator of protein breakdown and of muscle atrophy was differentially expressed: the gene was downregulated after lengthening contractions (3 h, 2.7-fold, P < 0.05; 6 h, 3.3-fold, P < 0.05; 24 h, 2.3-fold, P < 0.05). The results suggested that lengthening and shortening contractions activated distinct molecular pathways as early as 3 h postexercise. The molecular differences might contribute to mechanisms underlying the physiological adaptations seen with training using the two modes of exercise.
Collapse
Affiliation(s)
- Matthew C Kostek
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, District of Columbia 20010, USA
| | | | | | | | | | | | | |
Collapse
|
6
|
Sanger JW, Kang S, Siebrands CC, Freeman N, Du A, Wang J, Stout AL, Sanger JM. How to build a myofibril. J Muscle Res Cell Motil 2007; 26:343-54. [PMID: 16465476 DOI: 10.1007/s10974-005-9016-7] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Building a myofibril from its component proteins requires the interactions of many different proteins in a process whose details are not understood. Several models have been proposed to provide a framework for understanding the increasing data on new myofibrillar proteins and their localizations during muscle development. In this article we discuss four current models that seek to explain how the assembly occurs in vertebrate cross-striated muscles. The models hypothesize: (a) stress fiber-like structures as templates for the assembly of myofibrils, (b) assembly in which the actin filaments and Z-bands form subunits independently from A-band subunits, with the two subsequently joined together to form a myofibril, (c) premyofibrils as precursors of myofibrils, or (d) assembly occurring without any intermediary structures. The premyofibril model, proposed by the authors, is discussed in more detail as it could explain myofibrillogenesis under a variety of different conditions: in ovo, in explants, and in tissue culture studies on cardiac and skeletal muscles.
Collapse
Affiliation(s)
- Joseph W Sanger
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6058, USA.
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Boateng SY, Belin RJ, Geenen DL, Margulies KB, Martin JL, Hoshijima M, de Tombe PP, Russell B. Cardiac dysfunction and heart failure are associated with abnormalities in the subcellular distribution and amounts of oligomeric muscle LIM protein. Am J Physiol Heart Circ Physiol 2007; 292:H259-69. [PMID: 16963613 DOI: 10.1152/ajpheart.00766.2006] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Prolonged hemodynamic overload results in cardiac hypertrophy and failure with detrimental changes in myocardial gene expression and morphology. Cysteine-rich protein 3 or muscle LIM protein (MLP) is thought to be a mechanosensor in cardiac myocytes. Therefore, the subcellular location of MLP may have functional implications in health and disease. Our hypothesis is that MLP becomes mislocalized after prolonged overload, resulting in impaired mechanosensing in cardiac myocytes. Using the techniques of biochemical subcellular fractionation and immunocytochemistry, we found MLP exhibits oligomerization in the membrane and cytoskeleton of cultured cardiac rat neonatal myocytes. Nuclear MLP was always monomeric. MLP translocated to the nucleolus in response to 10% cyclic stretch at 1 Hz for 48 h. This was associated with a threefold increase in S6 ribosomal protein ( P < 0.01; n = 3 cultures). Adenoviral overexpression of MLP also resulted in a twofold increase in S6 protein, suggesting that MLP can activate ribosomal protein synthesis in the nucleolus. In ventricles from aortic-banded and myocardially infarcted rat hearts, nuclear MLP increased by twofold ( P < 0.01; n = 7) along with a significant decrease in the nonnuclear oligomeric fraction. The ratio of nuclear to nonnuclear MLP increased threefold in both groups ( P < 0.01; n = 7). In failing human hearts, there was almost a complete loss of oligomeric MLP. Using a flag-tagged adenoviral MLP, we demonstrate that the COOH terminus is required for oligomerization and that this is a precursor to stretch sensing and subsequent nuclear translocation. Therefore, reduced oligomeric MLP in the costamere and cytoskeleton may contribute to impaired mechanosensing in heart failure.
Collapse
Affiliation(s)
- Samuel Y Boateng
- Dept. of Physiology and Biophysics (M/C 901 Univ. of Illinois at Chicago, 835 S. Wolcott Ave., Chicago IL 60612-7342, USA
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Wilding JR, Joubert F, de Araujo C, Fortin D, Novotova M, Veksler V, Ventura-Clapier R. Altered energy transfer from mitochondria to sarcoplasmic reticulum after cytoarchitectural perturbations in mice hearts. J Physiol 2006; 575:191-200. [PMID: 16740607 PMCID: PMC1819422 DOI: 10.1113/jphysiol.2006.114116] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Sarcoplasmic reticulum (SR) calcium pump function requires a high local ATP/ADP ratio, which can be maintained by direct nucleotide channelling from mitochondria, and by SR-bound creatine kinase (CK)-catalysed phosphate-transfer from phosphocreatine. We hypothesized that SR calcium uptake supported by mitochondrial direct nucleotide channelling, but not bound CK, depends on the juxtaposition of these organelles. To test this, we studied a well-described model of cytoarchitectural disorganization, the muscle LIM protein (MLP)-null mouse heart. Subcellular organization was characterized using electron microscopy, and mitochondrial, SR and myofibrillar function were assessed in saponin-permeabilized fibres by measuring respiration rates and caffeine-induced tension transients. MLP-null hearts had fewer, less-tightly packed intermyofibrillar mitochondria, and more subsarcolemmal mitochondria. The apparent mitochondrial Km for ADP was significantly lower in the MLP-null heart than in control (175 +/- 15 and 270 +/- 33 microM, respectively), indicating greater ADP accessibility, although maximal respiration rate, mitochondrial content and total CK activity were unaltered. Active tension in the myofibres of MLP-null mice was 54% lower than in controls (39 +/- 3 and 18 +/- 1 mN mm(-2), respectively), consistent with cytoarchitectural disorganization. SR calcium loading in the myofibres of MLP-null mice was similar to that in control myofibres when energy support was provided via Bound CK, but approximately 36% lower than controls when energy support was provided by mitochondrial (P < 0.05). Mitochondrial support for SR calcium uptake was also specifically decreased in the desmin-null heart, which is another model of cytoarchitectural perturbation. Thus, despite normal oxidative capacity, direct nucleotide channelling to the SR was impaired in MLP deficiency, concomitant with looser mitochondrial packing and increased nucleotide accessibility to this organelle. Changes in cytoarchitecture may therefore impair subcellular energy transfer and contribute to energetic and contractile dysfunction.
Collapse
|
9
|
Abstract
Cardiac hypertrophy is caused by hypertension, myocardial infarction, endocrine disorders, and perturbations in sarcomeric function, and has become a major cause of human morbidity and mortality. The generation of cardiac hypertrophy is associated with regulation of a cardiac gene program by cardiac transcription factors. The LIM proteins have been discovered to play an important role in cardiac hypertrophy. The LIM proteins contain one, two or multiple LIM domains and can be divided into different classes according to their amino acid sequence homologies. The LIM-only proteins, muscle LIM protein and human heart LIM protein are involved in cardiac hypertrophy by functioning as either an integrator of protein assembly of the actin-based cytoskeleton or tissue-specific coactivator of the receptor and the transcription factors. There have been many recent developments in the functions of LIM proteins related to cardiac hypertrophy and their interactions. It is hoped that the knowledge of LIM proteins will at least provide a greater choice of therapies and improved our management of cardiac hypertrophy.
Collapse
Affiliation(s)
- Mei Han
- Institute of Basic Medicine, Department of Biochemistry and Molecular Biology, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Jin-Kun Wen
- Institute of Basic Medicine,Department of Biochemistry and Molecular No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Bin Zheng
- Institute of Basic Medicine,Department of Biochemistry and Molecular No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| |
Collapse
|
10
|
Abstract
The heart is the first organ to form in the embryo, and all subsequent events in the life of the organism depend on its function. Inherited mutations in cardiac regulatory genes give rise to congenital heart disease, the most common form of human birth defects, and abnormalities of the adult heart represent the most prevalent cause of morbidity and mortality in the industrialized world. The past decade has marked a transition from physiological and functional studies of the heart toward a deeper understanding of cardiac function (and dysfunction) at genetic and molecular levels. These discoveries have provided new therapeutic approaches for prevention and palliation of cardiac disease and have raised new questions, challenges and opportunities for the future.
Collapse
Affiliation(s)
- Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, 6000 Harry Hines Blvd., Dallas, Texas 75390-9148, USA.
| |
Collapse
|
11
|
Hoshijima M. Models of Dilated Cardiomyopathy in Small Animals and Novel Positive Inotropic Therapies. Ann N Y Acad Sci 2004; 1015:320-31. [PMID: 15201171 DOI: 10.1196/annals.1302.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Several randomized clinical trials of vesnarinone and milrinone in patients with heart failure left disappointing results in the 1990s. Thereafter, use of positive inotropic agents has been avoided. Exceptions are the use of digitalis glycosides to treat mild-moderate heart failure and the intravenous administration of catecholamines and phosphodiesterase inhibitors in patients with acute and/or refractory heart failure. It is not, however, exactly known whether chronic enhancement of cardiac contractility indeed has harmful effects, besides increased risk of arrhythmia and mortality. We investigated the potential chronic benefit of positive inotropic modification to treat progressive cardiomyopathy and associated heart failure using a genetic complementation strategy of muscle lim-protein and phospholamban (PLN) double mutagenesis in the mouse and found clear evidence of positive effects. Subsequent somatic modification of PLN function via gene transfer with recombinant adeno-associated virus vectors in small animal models of dilated cardiomyopathy further supported the chronic benefit of enhanced cardiac function achieved in an beta-adrenergic stimulus-independent manner. This study examines current small animal models of dilated cardiomyopathy and recent multiple attempts to use these models as novel gene-based inotropic therapies.
Collapse
Affiliation(s)
- Masahiko Hoshijima
- Institute of Molecular Medicine, Department of Medicine, University of California San Diego School of Medicine, La Jolla, CA 92093, USA.
| |
Collapse
|