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Delfín DA, Zang KE, Schill KE, Patel NT, Janssen PML, Raman SV, Rafael-Fortney JA. Cardiomyopathy in the dystrophin/utrophin-deficient mouse model of severe muscular dystrophy is characterized by dysregulation of matrix metalloproteinases. Neuromuscul Disord 2012; 22:1006-14. [PMID: 22749475 DOI: 10.1016/j.nmd.2012.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 04/30/2012] [Accepted: 05/03/2012] [Indexed: 10/28/2022]
Abstract
Cardiomyopathy is a significant component in Duchenne muscular dystrophy. Although mdx mice are deficient in dystrophin, they only develop mild indicators of cardiomyopathy before 1year-of-age, making therapeutic investigations using this model lengthy. In contrast, mdx mice also lacking utrophin (utrn(-/-);mdx) show severely reduced cardiac contractile function and histological indicators of cardiomyopathy by 8-10weeks-of-age. Here we demonstrate that utrn(-/-);mdx mice show a similar pattern of cardiac damage to that in dystrophic patients. Matrix metalloproteinases required for ventricular remodeling during the evolution of heart failure are upregulated in utrn(-/-);mdx mice concurrent with the onset of cardiac pathology by 10weeks-of-age. Matrix metalloproteinase activity is further dysregulated due to reduced levels of endogenous tissue inhibitors and co-localizes with fibroblasts and collagen I-containing scars. utrn(-/-);mdx mice are therefore a very useful model for investigating potential cardiac therapies.
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Affiliation(s)
- Dawn A Delfín
- Department of Molecular and Cellular Biochemistry, The Ohio State University, College of Medicine, Columbus, OH 43210, United States
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Reay DP, Niizawa GA, Watchko JF, Daood M, Reay JC, Raggi E, Clemens PR. Effect of nuclear factor κB inhibition on serotype 9 adeno-associated viral (AAV9) minidystrophin gene transfer to the mdx mouse. Mol Med 2012; 18:466-76. [PMID: 22231732 DOI: 10.2119/molmed.2011.00404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 01/05/2012] [Indexed: 02/01/2023] Open
Abstract
Gene therapy studies for Duchenne muscular dystrophy (DMD) have focused on viral vector-mediated gene transfer to provide therapeutic protein expression or treatment with drugs to limit dystrophic changes in muscle. The pathological activation of the nuclear factor (NF)-κB signaling pathway has emerged as an important cause of dystrophic muscle changes in muscular dystrophy. Furthermore, activation of NF-κB may inhibit gene transfer by promoting inflammation in response to the transgene or vector. Therefore, we hypothesized that inhibition of pathological NF-κB activation in muscle would complement the therapeutic benefits of dystrophin gene transfer in the mdx mouse model of DMD. Systemic gene transfer using serotype 9 adeno-associated viral (AAV9) vectors is promising for treatment of preclinical models of DMD because of vector tropism to cardiac and skeletal muscle. In quadriceps of C57BL/10ScSn-Dmd(mdx)/J (mdx) mice, the addition of octalysine (8K)-NF-κB essential modulator (NEMO)-binding domain (8K-NBD) peptide treatment to AAV9 minidystrophin gene delivery resulted in increased levels of recombinant dystrophin expression suggesting that 8K-NBD treatment promoted an environment in muscle tissue conducive to higher levels of expression. Indices of necrosis and regeneration were diminished with AAV9 gene delivery alone and to a greater degree with the addition of 8K-NBD treatment. In diaphragm muscle, high-level transgene expression was achieved with AAV9 minidystoophin gene delivery alone; therefore, improvements in histological and physiological indices were comparable in the two treatment groups. The data support benefit from 8K-NBD treatment to complement gene transfer therapy for DMD in muscle tissue that receives incomplete levels of transduction by gene transfer, which may be highly significant for clinical applications of muscle gene delivery.
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Affiliation(s)
- Daniel P Reay
- Neurology Service, Department of Veterans Affairs Medical Center, Pittsburgh, Pennsylvania 15213, USA
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Delfín DA, Xu Y, Schill KE, Mays TA, Canan BD, Zang KE, Barnum JA, Janssen PML, Rafael-Fortney JA. Sustaining cardiac claudin-5 levels prevents functional hallmarks of cardiomyopathy in a muscular dystrophy mouse model. Mol Ther 2012; 20:1378-83. [PMID: 22547149 DOI: 10.1038/mt.2012.81] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Identification of new molecular targets in heart failure could ultimately have a substantial positive impact on both the health and financial aspects of treating the large heart failure population. We originally identified reduced levels of the cell junction protein claudin-5 specifically in heart in the dystrophin/utrophin-deficient (Dmd(mdx);Utrn(-/-)) mouse model of muscular dystrophy and cardiomyopathy, which demonstrates physiological hallmarks of heart failure. We then showed that at least 60% of cardiac explant samples from patients with heart failure resulting from diverse etiologies also have reduced claudin-5 levels. These claudin-5 reductions were independent of changes in other cell junction proteins previously linked to heart failure. The goal of this study was to determine whether sustaining claudin-5 levels is sufficient to prevent the onset of histological and functional indicators of heart failure. Here, we show the proof-of-concept rescue experiment in the Dmd(mdx);Utrn(-/-) model, in which claudin-5 reductions were originally identified. Expression of claudin-5 4 weeks after a single administration of recombinant adeno-associated virus (rAAV) containing a claudin-5 expression cassette prevented the onset of physiological hallmarks of cardiomyopathy and improved histological signs of cardiac damage. This experiment demonstrates that claudin-5 may represent a novel treatment target for prevention of heart failure.
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Affiliation(s)
- Dawn A Delfín
- Department of Molecular and Cellular Biochemistry, College of Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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Chun JL, O’Brien R, Berry SE. Cardiac dysfunction and pathology in the dystrophin and utrophin-deficient mouse during development of dilated cardiomyopathy. Neuromuscul Disord 2012; 22:368-79. [DOI: 10.1016/j.nmd.2011.07.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 07/05/2011] [Indexed: 01/16/2023]
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Barnabei MS, Metzger JM. Ex vivo stretch reveals altered mechanical properties of isolated dystrophin-deficient hearts. PLoS One 2012; 7:e32880. [PMID: 22427904 PMCID: PMC3298453 DOI: 10.1371/journal.pone.0032880] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 02/06/2012] [Indexed: 12/12/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a progressive and fatal disease of muscle wasting caused by loss of the cytoskeletal protein dystrophin. In the heart, DMD results in progressive cardiomyopathy and dilation of the left ventricle through mechanisms that are not fully understood. Previous reports have shown that loss of dystrophin causes sarcolemmal instability and reduced mechanical compliance of isolated cardiac myocytes. To expand upon these findings, here we have subjected the left ventricles of dystrophin-deficient mdx hearts to mechanical stretch. Unexpectedly, isolated mdx hearts showed increased left ventricular (LV) compliance compared to controls during stretch as LV volume was increased above normal end diastolic volume. During LV chamber distention, sarcomere lengths increased similarly in mdx and WT hearts despite greater excursions in volume of mdx hearts. This suggests that the mechanical properties of the intact heart cannot be modeled as a simple extrapolation of findings in single cardiac myocytes. To explain these findings, a model is proposed in which disruption of the dystrophin-glycoprotein complex perturbs cell-extracellular matrix contacts and promotes the apparent slippage of myocytes past each other during LV distension. In comparison, similar increases in LV compliance were obtained in isolated hearts from β-sarcoglycan-null and laminin-α2 mutant mice, but not in dysferlin-null mice, suggesting that increased whole-organ compliance in mdx mice is a specific effect of disrupted cell-extracellular matrix contacts and not a general consequence of cardiomyopathy via membrane defect processes. Collectively, these findings suggest a novel and cell-death independent mechanism for the progressive pathological LV dilation that occurs in DMD.
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Affiliation(s)
| | - Joseph M. Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
- * E-mail:
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Abstract
The heart is frequently afflicted in muscular dystrophy. In severe cases, cardiac lesion may directly result in death. Over the years, pharmacological and/or surgical interventions have been the mainstay to alleviate cardiac symptoms in muscular dystrophy patients. Although these traditional modalities remain useful, the emerging field of gene therapy has now provided an unprecedented opportunity to transform our thinking/approach in the treatment of dystrophic heart disease. In fact, the premise is already in place for genetic correction. Gene mutations have been identified and animal models are available for several types of muscular dystrophy. Most importantly, innovative strategies have been developed to effectively deliver therapeutic genes to the heart. Dystrophin-deficient Duchenne cardiomyopathy is associated with Duchenne muscular dystrophy (DMD), the most common lethal muscular dystrophy. Considering its high incidence, there has been a considerable interest and significant input in the development of Duchenne cardiomyopathy gene therapy. Using Duchenne cardiomyopathy as an example, here we illustrate the struggles and successes experienced in the burgeoning field of dystrophic heart disease gene therapy. In light of abundant and highly promising data with the adeno-associated virus (AAV) vector, we have specially emphasized on AAV-mediated gene therapy. Besides DMD, we have also discussed gene therapy for treating cardiac diseases in other muscular dystrophies such as limb-girdle muscular dystrophy.
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Wong J, Zhang J, Yanagawa B, Luo Z, Yang X, Chang J, McManus B, Luo H. Cleavage of serum response factor mediated by enteroviral protease 2A contributes to impaired cardiac function. Cell Res 2012; 22:360-71. [PMID: 21769134 PMCID: PMC3271589 DOI: 10.1038/cr.2011.114] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 04/12/2011] [Accepted: 05/04/2011] [Indexed: 11/09/2022] Open
Abstract
Enteroviral infection can lead to dilated cardiomyopathy (DCM), which is a major cause of cardiovascular mortality worldwide. However, the pathogenetic mechanisms have not been fully elucidated. Serum response factor (SRF) is a cardiac-enriched transcription regulator controlling the expression of a variety of target genes, including those involved in the contractile apparatus and immediate early response, as well as microRNAs that silence the expression of cardiac regulatory factors. Knockout of SRF in the heart results in downregulation of cardiac contractile gene expression and development of DCM. The goal of this study is to understand the role of SRF in enterovirus-induced cardiac dysfunction and progression to DCM. Here we report that SRF is cleaved following enteroviral infection of mouse heart and cultured cardiomyocytes. This cleavage is accompanied by impaired cardiac function and downregulation of cardiac-specific contractile and regulatory genes. Further investigation by antibody epitope mapping and site-directed mutagenesis demonstrates that SRF cleavage occurs at the region of its transactivation domain through the action of virus-encoded protease 2A. Moreover, we demonstrate that cleavage of SRF dissociates its transactivation domain from DNA-binding domain, resulting in the disruption of SRF-mediated gene transactivation. In addition to loss of functional SRF, finally we report that the N-terminal fragment of SRF cleavage products can also act as a dominant-negative transcription factor, which likely competes with the native SRF for DNA binding. Our results suggest a mechanism by which virus infection impairs heart function and may offer a new therapeutic strategy to ameliorate myocardial damage and progression to DCM.
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Affiliation(s)
- Jerry Wong
- James Hogg iCAPTURE Centre, Providence Heart + Lung Institute, St Paul's Hospital and Department of Pathology and Laboratory Medicine, University of British Columbia, 1081 Burrard Street, Vancouver, BC V6Z 1Y, Canada
| | - Jingchun Zhang
- James Hogg iCAPTURE Centre, Providence Heart + Lung Institute, St Paul's Hospital and Department of Pathology and Laboratory Medicine, University of British Columbia, 1081 Burrard Street, Vancouver, BC V6Z 1Y, Canada
| | - Bobby Yanagawa
- James Hogg iCAPTURE Centre, Providence Heart + Lung Institute, St Paul's Hospital and Department of Pathology and Laboratory Medicine, University of British Columbia, 1081 Burrard Street, Vancouver, BC V6Z 1Y, Canada
| | - Zongshu Luo
- James Hogg iCAPTURE Centre, Providence Heart + Lung Institute, St Paul's Hospital and Department of Pathology and Laboratory Medicine, University of British Columbia, 1081 Burrard Street, Vancouver, BC V6Z 1Y, Canada
| | - Xiangsheng Yang
- Center for Molecular Development and Disease, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Jiang Chang
- Center for Molecular Development and Disease, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Bruce McManus
- James Hogg iCAPTURE Centre, Providence Heart + Lung Institute, St Paul's Hospital and Department of Pathology and Laboratory Medicine, University of British Columbia, 1081 Burrard Street, Vancouver, BC V6Z 1Y, Canada
| | - Honglin Luo
- James Hogg iCAPTURE Centre, Providence Heart + Lung Institute, St Paul's Hospital and Department of Pathology and Laboratory Medicine, University of British Columbia, 1081 Burrard Street, Vancouver, BC V6Z 1Y, Canada
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Alison B, Elizabeth G, Steve L, Andrew B, Guy M, Volker S. Animal Models of Duchenne Muscular Dystrophy, with Special Reference to the mdx Mouse. Biocybern Biomed Eng 2012. [DOI: 10.1016/s0208-5216(12)70045-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Verhaart IEC, van Duijn RJM, den Adel B, Roest AAW, Verschuuren JJGM, Aartsma-Rus A, van der Weerd L. Assessment of cardiac function in three mouse dystrophinopathies by magnetic resonance imaging. Neuromuscul Disord 2011; 22:418-26. [PMID: 22209498 DOI: 10.1016/j.nmd.2011.10.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 10/30/2011] [Indexed: 11/24/2022]
Abstract
Lack of dystrophin results in skeletal muscle dystrophy and dilated cardiomyopathy in humans and animal models. To achieve a basic understanding of the natural development of cardiomyopathy in different dystrophinopathy mouse models, left and right ventricular heart function was assessed at different ages in three dystrophinopathy mouse models (mdx, mdx/utrn(+/-) model and mdx/utrn(-/-)) using magnetic resonance imaging. Left ventricular function was significantly decreased, already at 2months in the most severely affected mdx/utrn(-/-) mice. Furthermore, whereas heart function was stable in wild-type mice over time, both mdx and mdx/utrn(+/-) showed a clear decrease at 10months of age, most prominently in the right ventricle. Therefore magnetic resonance imaging is an adequate technique to determine heart function in dystrophinopathy mouse models and can be used to assess the effect of potential therapies.
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Affiliation(s)
- Ingrid E C Verhaart
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Tang J, Tang S, Haldi M, Seng WL. Zebrafish Assays for Identifying Potential Muscular Dystrophy Drug Candidates. Zebrafish 2011. [DOI: 10.1002/9781118102138.ch18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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61
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Wehling-Henricks M, Tidball JG. Neuronal nitric oxide synthase-rescue of dystrophin/utrophin double knockout mice does not require nNOS localization to the cell membrane. PLoS One 2011; 6:e25071. [PMID: 22003386 PMCID: PMC3189177 DOI: 10.1371/journal.pone.0025071] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 08/26/2011] [Indexed: 02/03/2023] Open
Abstract
Survival of dystrophin/utrophin double-knockout (dko) mice was increased by muscle-specific expression of a neuronal nitric oxide synthase (nNOS) transgene. Dko mice expressing the transgene (nNOS TG+/dko) experienced delayed onset of mortality and increased life-span. The nNOS TG+/dko mice demonstrated a significant decrease in the concentration of CD163+, M2c macrophages that can express arginase and promote fibrosis. The decrease in M2c macrophages was associated with a significant reduction in fibrosis of heart, diaphragm and hindlimb muscles of nNOS TG+/dko mice. The nNOS transgene had no effect on the concentration of cytolytic, CD68+, M1 macrophages. Accordingly, we did not observe any change in the extent of muscle fiber lysis in the nNOS TG+/dko mice. These findings show that nNOS/NO (nitric oxide)-mediated decreases in M2c macrophages lead to a reduction in the muscle fibrosis that is associated with increased mortality in mice lacking dystrophin and utrophin. Interestingly, the dramatic and beneficial effects of the nNOS transgene were not attributable to localization of nNOS protein at the cell membrane. We did not detect any nNOS protein at the sarcolemma in nNOS TG+/dko muscles. This important observation shows that sarcolemmal localization is not necessary for nNOS to have beneficial effects in dystrophic tissue and the presence of nNOS in the cytosol of dystrophic muscle fibers can ameliorate the pathology and most importantly, significantly increase life-span.
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Affiliation(s)
- Michelle Wehling-Henricks
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California, United States of America
| | - James G. Tidball
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California, United States of America
- Molecular, Cellular and Integrative Physiology Program, University of California, Los Angeles, California, United States of America
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- * E-mail:
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Shin JH, Bostick B, Yue Y, Hajjar R, Duan D. SERCA2a gene transfer improves electrocardiographic performance in aged mdx mice. J Transl Med 2011; 9:132. [PMID: 21834967 PMCID: PMC3162513 DOI: 10.1186/1479-5876-9-132] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 08/11/2011] [Indexed: 12/27/2022] Open
Abstract
Background Cardiomyocyte calcium overloading has been implicated in the pathogenesis of Duchenne muscular dystrophy (DMD) heart disease. The cardiac isoform of sarcoplasmic reticulum calcium ATPase (SERCA2a) plays a major role in removing cytosolic calcium during heart muscle relaxation. Here, we tested the hypothesis that SERCA2a over-expression may mitigate electrocardiography (ECG) abnormalities in old female mdx mice, a murine model of DMD cardiomyopathy. Methods 1 × 1012 viral genome particles/mouse of adeno-associated virus serotype-9 (AAV-9) SERCA2a vector was delivered to 12-m-old female mdx mice (N = 5) via a single bolus tail vein injection. AAV transduction and the ECG profile were examined eight months later. Results The vector genome was detected in the hearts of all AAV-injected mdx mice. Immunofluorescence staining and western blot confirmed SERCA2a over-expression in the mdx heart. Untreated mdx mice showed characteristic tachycardia, PR interval reduction and QT interval prolongation. AAV-9 SERCA2a treatment corrected these ECG abnormalities. Conclusions Our results suggest that AAV SERCA2a therapy may hold great promise in treating dystrophin-deficient heart disease.
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Affiliation(s)
- Jin-Hong Shin
- Department of Molecular Microbiology and Immunology, School of Medicine, The University of Missouri, Columbia, MO, USA
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Rafael-Fortney JA, Chimanji NS, Schill KE, Martin CD, Murray JD, Ganguly R, Stangland JE, Tran T, Xu Y, Canan BD, Mays TA, Delfín DA, Janssen PM, Raman SV. Early treatment with lisinopril and spironolactone preserves cardiac and skeletal muscle in Duchenne muscular dystrophy mice. Circulation 2011; 124:582-8. [PMID: 21768542 PMCID: PMC3150227 DOI: 10.1161/circulationaha.111.031716] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Nearly universal cardiomyopathy in Duchenne muscular dystrophy (DMD) contributes to heart failure and death. Because DMD patients show myocardial fibrosis well before functional impairment, we postulated that earlier treatment using drugs with antifibrotic effect may be beneficial. METHODS AND RESULTS Three groups of 10 utrn(+/-);mdx, or "het" mice, deficient for dystrophin and haploinsufficient for utrophin with skeletal myopathy and cardiomyopathy that closely mimics clinical DMD were studied. One het group received spironolactone and lisinopril starting at 8 weeks of life (het-treated-8); a second received the same starting at 4 weeks of life (het-treated-4), and the third het group was untreated. At 20 weeks, all mice had normal ejection fractions though circumferential strain rate was abnormal (-0.21±0.08) in untreated hets. This improved to -0.40±0.07 in het-treated-8 mice (P=0.003) and further improved to -0.56±0.10 in het-treated-4 mice (P=0.014 for het-treated-4 versus het-treated-8). Treated mice showed less cardiomyocyte damage, with a 44% reduction in intracardiomyocyte serum immunoglobulin G localization in het-treated-8 mice (P<0.0001) and a further 53% reduction in het-treated-4 mice (P=0.0003 versus het-treated-8); matrix metalloproteinases were similarly reduced. Cardiac, limb, and diaphragm function by ex vivo muscle testing remained at 80% of normal with early treatment compared to a decline to 40% of normal skeletal muscle function without treatment. CONCLUSIONS These findings offer clinically available medications with proven antifibrotic effect as a new therapeutic strategy in DMD. Early initiation greatly attenuated myocardial disease and, for the first time with these drugs, improved skeletal myopathy. Thus, early initiation of such agents warrants further clinical evaluation to maintain ambulatory, respiratory, and cardiac function for patients with DMD and related myopathies.
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Affiliation(s)
- Jill A. Rafael-Fortney
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio USA
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio USA
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio USA
| | - Neeraj S. Chimanji
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio USA
| | - Kevin E. Schill
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio USA
| | - Christopher D. Martin
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio USA
| | - Jason D. Murray
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio USA
| | - Ranjit Ganguly
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio USA
| | - Jenna E. Stangland
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio USA
| | - Tam Tran
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio USA
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio USA
| | - Ying Xu
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio USA
| | - Benjamin D. Canan
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio USA
| | - Tessily A. Mays
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio USA
| | - Dawn A. Delfín
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio USA
| | - Paul M.L. Janssen
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio USA
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio USA
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio USA
| | - Subha V. Raman
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio USA
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio USA
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Koenig X, Dysek S, Kimbacher S, Mike AK, Cervenka R, Lukacs P, Nagl K, Dang XB, Todt H, Bittner RE, Hilber K. Voltage-gated ion channel dysfunction precedes cardiomyopathy development in the dystrophic heart. PLoS One 2011; 6:e20300. [PMID: 21677768 PMCID: PMC3100353 DOI: 10.1371/journal.pone.0020300] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 04/24/2011] [Indexed: 12/15/2022] Open
Abstract
Background Duchenne muscular dystrophy (DMD), caused by mutations in the dystrophin gene, is associated with severe cardiac complications including cardiomyopathy and cardiac arrhythmias. Recent research suggests that impaired voltage-gated ion channels in dystrophic cardiomyocytes accompany cardiac pathology. It is, however, unknown if the ion channel defects are primary effects of dystrophic gene mutations, or secondary effects of the developing cardiac pathology. Methodology/Principal Findings To address this question, we first investigated sodium channel impairments in cardiomyocytes derived from dystrophic neonatal mice prior to cardiomyopahty development, by using the whole cell patch clamp technique. Besides the most common model for DMD, the dystrophin-deficient mdx mouse, we also used mice additionally carrying an utrophin mutation. In neonatal cardiomyocytes, dystrophin-deficiency generated a 25% reduction in sodium current density. In addition, extra utrophin-deficiency significantly altered sodium channel gating parameters. Moreover, also calcium channel inactivation was considerably reduced in dystrophic neonatal cardiomyocytes, suggesting that ion channel abnormalities are universal primary effects of dystrophic gene mutations. To assess developmental changes, we also studied sodium channel impairments in cardiomyocytes derived from dystrophic adult mice, and compared them with the respective abnormalities in dystrophic neonatal cells. Here, we found a much stronger sodium current reduction in adult cardiomyocytes. The described sodium channel impairments slowed the upstroke of the action potential in adult cardiomyocytes, and only in dystrophic adult mice, the QRS interval of the electrocardiogram was prolonged. Conclusions/Significance Ion channel impairments precede pathology development in the dystrophic heart, and may thus be considered potential cardiomyopathy triggers.
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MESH Headings
- Action Potentials/physiology
- Animals
- Animals, Newborn
- Barium/metabolism
- Calcium Channels, L-Type/metabolism
- Cardiomyopathies/pathology
- Cardiomyopathies/physiopathology
- Cells, Cultured
- Dystrophin/genetics
- Electrocardiography
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/pathology
- Muscular Dystrophy, Duchenne/physiopathology
- Mutation
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Patch-Clamp Techniques
- Sodium/metabolism
- Sodium Channels/metabolism
- Utrophin/deficiency
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Affiliation(s)
- Xaver Koenig
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Sandra Dysek
- Center for Anatomy and Cell Biology, Neuromuscular Research Department, Medical University of Vienna, Vienna, Austria
| | - Stefanie Kimbacher
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Center for Anatomy and Cell Biology, Neuromuscular Research Department, Medical University of Vienna, Vienna, Austria
| | - Agnes K. Mike
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Rene Cervenka
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Peter Lukacs
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Katrin Nagl
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Xuan B. Dang
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Hannes Todt
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Reginald E. Bittner
- Center for Anatomy and Cell Biology, Neuromuscular Research Department, Medical University of Vienna, Vienna, Austria
| | - Karlheinz Hilber
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- * E-mail:
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Delfín DA, Xu Y, Peterson JM, Guttridge DC, Rafael-Fortney JA, Janssen PM. Improvement of cardiac contractile function by peptide-based inhibition of NF-κB in the utrophin/dystrophin-deficient murine model of muscular dystrophy. J Transl Med 2011; 9:68. [PMID: 21586145 PMCID: PMC3212940 DOI: 10.1186/1479-5876-9-68] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 05/17/2011] [Indexed: 02/07/2023] Open
Abstract
Background Duchenne muscular dystrophy (DMD) is an inherited and progressive disease causing striated muscle deterioration. Patients in their twenties generally die from either respiratory or cardiac failure. In order to improve the lifespan and quality of life of DMD patients, it is important to prevent or reverse the progressive loss of contractile function of the heart. Recent studies by our labs have shown that the peptide NBD (Nemo Binding Domain), targeted at blunting Nuclear Factor κB (NF-κB) signaling, reduces inflammation, enhances myofiber regeneration, and improves contractile deficits in the diaphragm in dystrophin-deficient mdx mice. Methods To assess whether cardiac function in addition to diaphragm function can be improved, we investigated physiological and histological parameters of cardiac muscle in mice deficient for both dystrophin and its homolog utrophin (double knockout = dko) mice treated with NBD peptide. These dko mice show classic pathophysiological hallmarks of heart failure, including myocyte degeneration, an impaired force-frequency response and a severely blunted β-adrenergic response. Cardiac contractile function at baseline and frequencies and pre-loads throughout the in vivo range as well as β-adrenergic reserve was measured in isolated cardiac muscle preparations. In addition, we studied histopathological and inflammatory markers in these mice. Results At baseline conditions, active force development in cardiac muscles from NBD treated dko mice was more than double that of vehicle-treated dko mice. NBD treatment also significantly improved frequency-dependent behavior of the muscles. The increase in force in NBD-treated dko muscles to β-adrenergic stimulation was robustly restored compared to vehicle-treated mice. However, histological features, including collagen content and inflammatory markers were not significantly different between NBD-treated and vehicle-treated dko mice. Conclusions We conclude that NBD can significantly improve cardiac contractile dysfunction in the dko mouse model of DMD and may thus provide a novel therapeutic treatment for heart failure.
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Affiliation(s)
- Dawn A Delfín
- Department of Physiology and Cell Biology, Columbus, OH, USA
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66
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Shin JH, Nitahara-Kasahara Y, Hayashita-Kinoh H, Ohshima-Hosoyama S, Kinoshita K, Chiyo T, Okada H, Okada T, Takeda S. Improvement of cardiac fibrosis in dystrophic mice by rAAV9-mediated microdystrophin transduction. Gene Ther 2011; 18:910-9. [PMID: 21451578 DOI: 10.1038/gt.2011.36] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is the most common form of the progressive muscular dystrophies characterized by defects of the dystrophin gene. Although primarily characterized by degeneration of the limb muscles, cardiomyopathy is a major cause of death. Therefore, the development of curative modalities such as gene therapy is imperative. We evaluated the cardiomyopathic features of mdx mice to observe improvements in response to intravenous administration of recombinant adeno-associated virus (AAV) type 9 encoding microdystrophin. The myocardium was extensively transduced with microdystrophin to significantly prevent the development of fibrosis, and expression persisted for the duration of the study. Intraventricular conduction patterns, such as the QRS complex duration and S/R ratio in electrocardiography, were also corrected, indicating that the transduced microdystrophin has a protective effect on the dystrophin-deficient myocardium. Furthermore, BNP and ANP levels were reduced to normal, suggesting the absence of cardiac dysfunction. In aged mice, prevention of ectopic beats as well as echocardiographic amelioration was also demonstrated with improved exercise performance. These findings indicate that AAV-mediated cardiac transduction with microdystrophin might be a promising therapeutic strategy for the treatment of dystrophin-deficient cardiomyopathy.
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Affiliation(s)
- J-H Shin
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
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Peterson JM, Kline W, Canan BD, Ricca DJ, Kaspar B, Delfín DA, DiRienzo K, Clemens PR, Robbins PD, Baldwin AS, Flood P, Kaumaya P, Freitas M, Kornegay JN, Mendell JR, Rafael-Fortney JA, Guttridge DC, Janssen PML. Peptide-based inhibition of NF-κB rescues diaphragm muscle contractile dysfunction in a murine model of Duchenne muscular dystrophy. Mol Med 2011; 17:508-15. [PMID: 21267511 DOI: 10.2119/molmed.2010.00263] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 01/19/2011] [Indexed: 11/06/2022] Open
Abstract
Deterioration of diaphragm function is one of the prominent factors that contributes to the susceptibility of serious respiratory infections and development of respiratory failure in patients with Duchenne Muscular Dystrophy (DMD). The NF-κB signaling pathway has been implicated as a contributing factor of dystrophic pathology, making it a potential therapeutic target. Previously, we demonstrated that pharmacological inhibition of NF-κB via a small NEMO Binding Domain (NBD) peptide was beneficial for reducing pathological features of mdx mice. Now, we stringently test the effectiveness and clinical potential of NBD by treating mdx mice with various formulations of NBD and use diaphragm function as our primary outcome criteria. We found that administering DMSO-soluble NBD rescued 78% of the contractile deficit between mdx and wild-type (WT) diaphragm. Interestingly, synthesis of a GLP NBD peptide as an acetate salt permitted its solubility in water, but as a negative consequence, also greatly attenuated functional efficacy. However, replacing the acetic acid counterion of the NBD peptide with trifluoroacetic acid retained the peptide's water solubility and significantly restored mdx diaphragm contractile function and improved histopathological indices of disease in both diaphragm and limb muscle. Together, these results support the feasibility of using a mass-produced, water-soluble NBD peptide for clinical use.
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Affiliation(s)
- Jennifer M Peterson
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, Ohio 43210, USA
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Xu Y, Delfín DA, Rafael-Fortney JA, Janssen PML. Lengthening-contractions in isolated myocardium impact force development and worsen cardiac contractile function in the mdx mouse model of muscular dystrophy. J Appl Physiol (1985) 2010; 110:512-9. [PMID: 21127205 DOI: 10.1152/japplphysiol.00253.2010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Lengthening-contractions exert eccentric stress on myofibers in normal myocardium. In congestive heart failure caused by a variety of diseases, the impact of lengthening-contractions of myocardium likely becomes more prevalent and severe. The present study introduces a method to investigate the role of stretching imposed by repetitive lengthening-contractions in myocardium under near-physiological conditions. By exerting various stretch-release ramps while the muscle is contracting, consecutive lengthening-contractions and their potential detrimental effect on cardiac function can be studied. We tested our model and hypothesis in age-matched (young and adult) mdx and wild-type mouse right ventricular trabeculae. These linear and ultrathin muscles possess all major cardiac cell types, and their contractile behavior very closely mimics that of the whole myocardium. In the first group of experiments, 10 lengthening-contractions at various magnitudes of stretch were performed in trabeculae from 10-wk-old mdx and wild-type mice. In the second group, 100 lengthening-contractions at various magnitudes were conducted in trabeculae from 10- and 20-wk-old mice. The peak isometric active developed tension (F(dev), in mN/mm(2)) and kinetic parameters time to peak tension (TTP, in ms) and time from peak tension to half-relaxation (RT50, in ms) were measured. Our results indicate lengthening-contractions significantly impact contractile behavior, and that dystrophin-deficient myocardium in mdx mice is significantly more susceptible to these damaging lengthening-contractions. The results indicate that lengthening-contractions in intact myocardium can be used in vitro to study this emerging contributor to cardiomyopathy.
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Affiliation(s)
- Ying Xu
- Dept. of Physiology and Cell Biology, The Ohio State Univ., 304 Hamilton Hall, 1645 Neil Ave., Columbus, OH 43210-1218, USA
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69
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Ameen V, Robson LG. Experimental models of duchenne muscular dystrophy: relationship with cardiovascular disease. Open Cardiovasc Med J 2010; 4:265-77. [PMID: 21258567 PMCID: PMC3024556 DOI: 10.2174/1874192401004010265] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 09/28/2010] [Accepted: 10/04/2010] [Indexed: 01/15/2023] Open
Abstract
Almost every boy that has Duchenne Muscular Dystrophy (DMD) will develop cardiac problems. Whereas, it used to be respiratory problems that was the main cause of death in these DMD boys; with the advent of better respiratory care it is now the cardiac involvement that is becoming the most common cause of their death. Once the heart is affected, there is progressive deterioration in the function of the heart over time. The main problem is the death of the cardiomyocytes. The cause of the cardiomyocyte death is due to the loss of dystrophin, this makes the sarcolemma more susceptible to damage, and leads to a cascade of calcium influx, calcium activated proteases and ultimately the death of the cardiomyocyte. The dead cardiomyocytes are replaced by fibrotic tissue, which results in a dilated cardiomyopathy (DCM) developing, which begins in the base of the left ventricle and progresses to involve the entire left ventricle. The treatments used for the DMD cardiomyopathy are based on ones designed for other forms of cardiac weakness and include ACE-inhibitors and β-blockers. New therapies based around the pathophysiology in DMD are now being introduced. This review will look at the pathophysiology of the cardiac problems in DMD and how the various animal models that are available can be used to design new treatment options for DMD boys.
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Affiliation(s)
- Venus Ameen
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, Blizard Institute of Cell and Molecular Science, Turner Street, London E1 2AD, UK
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Chandrasekharan K, Yoon JH, Xu Y, deVries S, Camboni M, Janssen PML, Varki A, Martin PT. A human-specific deletion in mouse Cmah increases disease severity in the mdx model of Duchenne muscular dystrophy. Sci Transl Med 2010; 2:42ra54. [PMID: 20668298 DOI: 10.1126/scitranslmed.3000692] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
During the evolution of humans, an inactivating deletion was introduced in the CMAH (cytidine monophosphate-sialic acid hydroxylase) gene, which eliminated biosynthesis of the common mammalian sialic acid N-glycolylneuraminic acid from all human cells. We found that this human-specific change in sialylation capacity contributes to the marked discrepancy in phenotype between the mdx mouse model for Duchenne muscular dystrophy (DMD) and the human disease. When compared to human patients with DMD, mdx mice show reduced severity or slower development of clinically relevant disease phenotypes, despite lacking dystrophin protein in almost all muscle cells. This is especially true for the loss of ambulation, cardiac and respiratory muscle weakness, and decreased life span, all of which are major phenotypes contributing to DMD morbidity and mortality. These phenotypes occur at an earlier age or to a greater degree in mdx mice that also carry a human-like mutation in the mouse Cmah gene, possibly as a result of reduced strength and expression of the dystrophin-associated glycoprotein complex and increased activation of complement. Cmah-deficient mdx mice are a small-animal model for DMD that better approximates the human glycome and its contributions to muscular dystrophy.
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Affiliation(s)
- Kumaran Chandrasekharan
- Center for Gene Therapy, Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
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71
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Janssen PML. Kinetics of cardiac muscle contraction and relaxation are linked and determined by properties of the cardiac sarcomere. Am J Physiol Heart Circ Physiol 2010; 299:H1092-9. [PMID: 20656885 PMCID: PMC2957358 DOI: 10.1152/ajpheart.00417.2010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 07/21/2010] [Indexed: 01/08/2023]
Abstract
The regulation of myocardial contraction and relaxation kinetics is currently incompletely understood. When the amplitude of contraction is increased via the Frank-Starling mechanism, the kinetics of the contraction slow down, but when the amplitude of contraction is increased with either an increase in heart rate or via β-adrenergic stimulation, the kinetics speed up. It is also unknown how physiological mechanisms affect the kinetics of contraction versus those of relaxation. We investigated contraction-relaxation coupling in isolated trabeculae from the mouse and rat and stimulated them to contract at various temperatures, frequencies, preloads, and in the absence and presence of β-adrenergic stimulation. In each muscle at least 16 different conditions were assessed, and the correlation coefficient of the speed of contraction and relaxation was very close (generally >0.98). Moreover, in all but one of the analyzed murine strains, the ratio of the minimum rate of the derivative of force development (dF/dt) over maximum dF/dt was not significantly different. Only in trabeculae isolated from myosin-binding protein-C mutant mice was this ratio significantly lower (0.61 ± 0.07 vs. 0.84 ± 0.02 in 11 other strains of mice). Within each strain, this ratio was unaffected by modulation of length, frequency, or β-adrenergic stimulation. Rat trabeculae showed identical results; the balance between kinetics of contraction and relaxation was generally constant (0.85 ± 0.04). Because of the great variety in underlying excitation-contraction coupling in the assessed strains, we concluded that contraction-relation coupling is a property residing in the cardiac sarcomere.
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Affiliation(s)
- Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, Columbus, OH 43210-1218, USA.
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72
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Abstract
Since the pioneering work of Henry Pickering Bowditch in the late 1800s to early 1900s, cardiac muscle contraction has remained an intensely studied topic for several reasons. The heart is located centrally in our body, and its pumping motion demands the attention of the observer. The contraction of the heart encompasses a complex interplay of mechanical, chemical, and electrical properties, and its function can thus be studied from any of these viewpoints. In addition, diseases of the heart are currently killing more people in the Westernized world than any other disease. When combined with the increasing emphasis of research to be clinically relevant, this contributes to the heart remaining a topic of continued basic and clinical investigation. Yet, there are significant aspects of cardiac muscle contraction that are still not well understood. A big complication of the study of cardiac muscle contraction is that there exists no equilibrium among many of the important governing parameters, which include pre- and afterload, intracellular ion concentrations, membrane potential, and velocity and direction of movement. Thus the classic approach of perturbing an equilibrium or a steady state to learn about the role of the perturbing factor in the system cannot be unambiguously interpreted, since each of the parameters that govern contraction are constantly changing, as well as constantly changing their interaction with each other. In this review, presented as the 54th Bowditch Lecture at Experimental Biology meeting in Anaheim in April 2010, I will revisit several governing factors of cardiac muscle relaxation by applying newly developed tools and protocols to isolated cardiac muscle tissue in which the dynamic interactions between the governing factors of contraction and relaxation can be studied.
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Affiliation(s)
- Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, Columbus, Ohio 43210-1218, USA.
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73
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Abstract
The muscular dystrophies are a group of neuromuscular disorders associated with muscle weakness and wasting, which in many forms can lead to loss of ambulation and premature death. A number of muscular dystrophies are associated with loss of proteins required for the maintenance of muscle membrane integrity, in particular with proteins that comprise the dystrophin-associated glycoprotein (DAG) complex. Proper glycosylation of O-linked mannose chains on alpha-dystroglycan, a DAG member, is required for the binding of the extracellular matrix to dystroglycan and for proper DAG function. A number of congenital disorders of glycosylation have now been described where alpha-dystroglycan glycosylation is altered and where muscular dystrophy is a predominant phenotype. Glycosylation is also increasingly being appreciated as a genetic modifier of disease phenotypes in many forms of muscular dystrophy and as a target for the development of new therapies. Here we will review the mouse models available for the study of this group of diseases and outline the methodologies required to describe disease phenotypes.
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Burelle Y, Khairallah M, Ascah A, Allen BG, Deschepper CF, Petrof BJ, Des Rosiers C. Alterations in mitochondrial function as a harbinger of cardiomyopathy: lessons from the dystrophic heart. J Mol Cell Cardiol 2009; 48:310-21. [PMID: 19769982 DOI: 10.1016/j.yjmcc.2009.09.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 09/03/2009] [Accepted: 09/09/2009] [Indexed: 10/20/2022]
Abstract
While compelling evidence supports the central role of mitochondrial dysfunction in the pathogenesis of heart failure, there is comparatively less information available on mitochondrial alterations that occur prior to failure. Building on our recent work with the dystrophin-deficient mdx mouse heart, this review focuses on how early changes in mitochondrial functional phenotype occur prior to overt cardiomyopathy and may be a determinant for the development of adverse cardiac remodelling leading to failure. These include alterations in energy substrate utilization and signalling of cell death through increased permeability of mitochondrial membranes, which may result from abnormal calcium handling, and production of reactive oxygen species. Furthermore, we will discuss evidence supporting the notion that these alterations in the dystrophin-deficient heart may represent an early "subclinical" signature of a defective nitric oxide/cGMP signalling pathway, as well as the potential benefit of mitochondria-targeted therapies. While the mdx mouse is an animal model of Duchenne muscular dystrophy (DMD), changes in the structural integrity of dystrophin, the mutated cytoskeletal protein responsible for DMD, have also recently been implicated as a common mechanism for contractile dysfunction in heart failure. In fact, altogether our findings support a critical role for dystrophin in maintaining optimal coupling between metabolism and contraction in the heart.
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Affiliation(s)
- Yan Burelle
- Department of Kinesiology, Université de Montréal, Montreal, Quebec, Canada
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75
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Townsend D, Yasuda S, Chamberlain J, Metzger JM. Cardiac consequences to skeletal muscle-centric therapeutics for Duchenne muscular dystrophy. Trends Cardiovasc Med 2009; 19:50-55. [PMID: 19577712 DOI: 10.1016/j.tcm.2009.04.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a fatal disease of muscle deterioration. Duchenne muscular dystrophy affects all striated muscles in the body, including the heart. Recent advances in palliative care, largely directed at improving respiratory function, have extended life but paradoxically further unmasked emergent heart disease in DMD patients. New experimental strategies have shown promise in restoring dystrophin in the skeletal muscles of dystrophin- deficient animals. These strategies often have little or no capacity for restitution of dystrophin in the hearts of these animals. This article draws on both clinical data and recent experimental data to posit that effective skeletal muscle restricted therapies for DMD will paradoxically heighten cardiomyopathy and heart failure in these patients.
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Affiliation(s)
- DeWayne Townsend
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA.
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76
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The value of mammalian models for duchenne muscular dystrophy in developing therapeutic strategies. Curr Top Dev Biol 2009; 84:431-53. [PMID: 19186250 DOI: 10.1016/s0070-2153(08)00609-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy. There is no effective treatment and patients typically die in approximately the third decade. DMD is an X-linked recessive disease caused by mutations in the dystrophin gene. There are three mammalian models of DMD that have been used to understand better the pathogenesis of disease and develop therapeutic strategies. The mdx mouse is the most widely used model of DMD that displays some features of muscle degeneration, but the pathogenesis of disease is comparatively mild. The severity of disease in mice lacking both dystrophin and utrophin is similar to DMD, but one has to account for the discrete functions of utrophin. Canine X-linked muscular dystrophy (cxmd) is the best representation of DMD, but the phenotype of the most widely used golden retriever (GRMD) model is variable, making functional endpoints difficult to ascertain. Although each mammalian model has its limitations, together they have been essential for the development of several treatment strategies for DMD that target dystrophin replacement, disease progression, and muscle regeneration.
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Willmann R, Possekel S, Dubach-Powell J, Meier T, Ruegg MA. Mammalian animal models for Duchenne muscular dystrophy. Neuromuscul Disord 2009; 19:241-9. [PMID: 19217290 DOI: 10.1016/j.nmd.2008.11.015] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 11/24/2008] [Accepted: 11/27/2008] [Indexed: 11/27/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disease that affects boys and leads to early death. In the quest for new treatments that improve the quality of life and in the search for a possible definitive cure, the use of animal models plays undoubtedly an important role. Therefore, a number of different mammalian models for DMD have been described. Much knowledge on the molecular mechanisms underlying the disease has arisen from studies in these animals. However, the use of different models does not often allow a direct comparison of results obtained in preclinical trials and therefore hinders a straightforward translational research. In the frame of "TREAT-NMD", a European Network of Excellence addressing the fragmentation in the assessment and treatment of neuromuscular diseases, we compare here the currently used mammalian animal models for DMD with the aim of selecting and recommending the most appropriate ones for preclinical efficacy testing of new therapeutic strategies.
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Affiliation(s)
- Raffaella Willmann
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
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78
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Davis J, Westfall MV, Townsend D, Blankinship M, Herron TJ, Guerrero-Serna G, Wang W, Devaney E, Metzger JM. Designing heart performance by gene transfer. Physiol Rev 2008; 88:1567-651. [PMID: 18923190 DOI: 10.1152/physrev.00039.2007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The birth of molecular cardiology can be traced to the development and implementation of high-fidelity genetic approaches for manipulating the heart. Recombinant viral vector-based technology offers a highly effective approach to genetically engineer cardiac muscle in vitro and in vivo. This review highlights discoveries made in cardiac muscle physiology through the use of targeted viral-mediated genetic modification. Here the history of cardiac gene transfer technology and the strengths and limitations of viral and nonviral vectors for gene delivery are reviewed. A comprehensive account is given of the application of gene transfer technology for studying key cardiac muscle targets including Ca(2+) handling, the sarcomere, the cytoskeleton, and signaling molecules and their posttranslational modifications. The primary objective of this review is to provide a thorough analysis of gene transfer studies for understanding cardiac physiology in health and disease. By comparing results obtained from gene transfer with those obtained from transgenesis and biophysical and biochemical methodologies, this review provides a global view of cardiac structure-function with an eye towards future areas of research. The data presented here serve as a basis for discovery of new therapeutic targets for remediation of acquired and inherited cardiac diseases.
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Affiliation(s)
- Jennifer Davis
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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79
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Mays TA, Binkley PF, Lesinski A, Doshi AA, Quaile MP, Margulies KB, Janssen PM, Rafael-Fortney JA. Claudin-5 levels are reduced in human end-stage cardiomyopathy. J Mol Cell Cardiol 2008; 45:81-7. [DOI: 10.1016/j.yjmcc.2008.04.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 04/15/2008] [Accepted: 04/16/2008] [Indexed: 11/27/2022]
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80
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Elsherif L, Huang MS, Shai SY, Yang Y, Li RY, Chun J, Mekany MA, Chu AL, Kaufman SJ, Ross RS. Combined deficiency of dystrophin and beta1 integrin in the cardiac myocyte causes myocardial dysfunction, fibrosis and calcification. Circ Res 2008; 102:1109-17. [PMID: 18340010 DOI: 10.1161/circresaha.108.173153] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The dystrophin-glycoprotein complex is a large complex of membrane-associated proteins linking the cytoskeleton to the extracellular matrix in muscle. Transmembrane heterodimeric (alphabeta) integrins serve also as cellular adhesion molecules and mechanotransducers. In the animal model for Duchenne muscular dystrophy, the mdx mouse, loss of dystrophin causes more severe abnormalities in skeletal than in cardiac muscle. We hypothesized that ablation of cardiac myocyte integrins in the mdx background would lead to a severe cardiomyopathic phenotype. Mdx mice were crossed to ones with cardiac myocyte-specific deletion of beta1 integrin (beta1KO) to generate beta1KOmdx. Unstressed beta1KOmdx mice were viable and had normal cardiac function; however, high mortality was seen in peri- and postpartum females by 6 months of age, when severe myocardial necrosis and fibrosis and extensive dystrophic calcification was seen. Decreased ventricular function and blunted adrenergic responsiveness was found in the beta1KOmdx mice compared with control (Lox/Lox, no Cre), beta1KO, and mdx. Similarly, adult beta1KOmdx males were more prone to isoproterenol-induced heart failure and death compared with control groups. Given the extensive calcification, we analyzed transcript levels of genes linked to fibrosis and calcification and found matrix gamma-carboxyglutamic acid protein, decorin, periostin, and the osteoblast transcription factor Runx2/Cbfa1 significantly increased in beta1KOmdx cardiac muscle. Our data show that combined deficiency of dystrophin and integrins in murine cardiac myocytes results in more severe cardiomyopathic changes in the stressed myocardium than reduction of either dystrophin or integrins alone and predisposes to myocardial calcification.
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Affiliation(s)
- Laila Elsherif
- Department of Medicine, University of California at San Diego School of Medicine, La Jolla, USA
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81
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Jung C, Martins AS, Niggli E, Shirokova N. Dystrophic cardiomyopathy: amplification of cellular damage by Ca2+ signalling and reactive oxygen species-generating pathways. Cardiovasc Res 2007; 77:766-73. [PMID: 18056762 DOI: 10.1093/cvr/cvm089] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
AIMS Cardiac myopathies are the second leading cause of death in patients with Duchenne and Becker muscular dystrophy, the two most common and severe forms of a disabling striated muscle disease. Although the genetic defect has been identified as mutations of the dystrophin gene, very little is known about the molecular and cellular events leading to progressive cardiac muscle damage. Dystrophin is a protein linking the cytoskeleton to a complex of transmembrane proteins that interact with the extracellular matrix. The fragility of the cell membrane resulting from the lack of dystrophin is thought to cause an excessive susceptibility to mechanical stress. Here, we examined cellular mechanisms linking the initial membrane damage to the dysfunction of dystrophic heart. METHODS AND RESULTS Cardiac ventricular myocytes were enzymatically isolated from 5- to 9-month-old dystrophic mdx and wild-type (WT) mice. Cells were exposed to mechanical stress, applied as osmotic shock. Stress-induced cytosolic and mitochondrial Ca(2+) signals, production of reactive oxygen species (ROS), and mitochondrial membrane potential were monitored with confocal microscopy and fluorescent indicators. Pharmacological tools were used to scavenge ROS and to identify their possible sources. Osmotic shock triggered excessive cytosolic Ca(2+) signals, often lasting for several minutes, in 82% of mdx cells. In contrast, only 47% of the WT cardiomyocytes responded with transient and moderate intracellular Ca(2+) signals. On average, the reaction was 6-fold larger in mdx cells. Removal of extracellular Ca(2+) abolished these responses, implicating Ca(2+) influx as a trigger for abnormal Ca(2+) signalling. Our further experiments revealed that osmotic stress in mdx cells produced an increase in ROS production and mitochondrial Ca(2+) overload. The latter was followed by collapse of the mitochondrial membrane potential, an early sign of cell death. CONCLUSION Overall, our findings reveal that excessive intracellular Ca(2+) signals and ROS generation link the initial sarcolemmal injury to mitochondrial dysfunctions. The latter possibly contribute to the loss of functional cardiac myocytes and heart failure in dystrophy. Understanding the sequence of events of dystrophic cell damage and the deleterious amplification systems involved, including several positive feed-back loops, may allow for a rational development of novel therapeutic strategies.
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Affiliation(s)
- Carole Jung
- Department of Physiology, University of Bern, Bern, Switzerland
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82
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Bostick B, Yue Y, Long C, Duan D. Prevention of dystrophin-deficient cardiomyopathy in twenty-one-month-old carrier mice by mosaic dystrophin expression or complementary dystrophin/utrophin expression. Circ Res 2007; 102:121-30. [PMID: 17967782 DOI: 10.1161/circresaha.107.162982] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A cure for dystrophin-deficient muscular dystrophy requires treating both skeletal muscle and the heart. Whereas mosaic dystrophin expression has been shown to protect skeletal muscle, controversy exists over whether mosaic expression is protective in the heart. We have shown recently that mosaic dystrophin expression prevents stress-induced heart damage in young carrier mice. Although an interesting finding, the clinical relevance remains to be established because young dystrophin-null mdx mice do not have heart disease. On the other hand, heart failure has been reported in human carriers. To resolve this mouse/human discrepancy, we evaluated the cardiac phenotype in 21-month-old mdx, carrier, and normal mice. We found dilated cardiomyopathy in old mdx mice but not in age-matched carrier mice. All anatomical parameters and physiological assay results (ECG and closed-chest Millar catheter) were within the normal range in old carrier mice. Focal myocardial inflammation was found in a small fraction of old carrier mice, but it had no major impact on heart function. Dobutamine stress revealed a near normal hemodynamic profile except for a marginal reduction in systolic pressure in old carrier mice. Immunostaining and Western blot showed dystrophin expression in 50% cardiomyocytes in old carrier mice. Interestingly, utrophin was upregulated in dystrophin-negative heart cells in carrier mice. In summary, we have provided the first clear-cut evidence that dilated cardiomyopathy in old mdx mice was prevented by mosaic dystrophin expression or complementary dystrophin/utrophin expression. Our results raise the hope for ameliorating dystrophic cardiomyopathy through partial gene and/or cell therapy.
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Affiliation(s)
- Brian Bostick
- Department of Molecular Microbiology and Immunology, The University of Missouri, School of Medicine, One Hospital Dr, M610G, MSB, Columbia, MO 65212, USA
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83
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Cardiac electrophysiological characteristics of the mdx 5cv mouse model of Duchenne muscular dystrophy. J Interv Card Electrophysiol 2007; 20:1-7. [DOI: 10.1007/s10840-007-9168-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 09/27/2007] [Indexed: 10/22/2022]
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84
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Zhou L, Rafael-Fortney JA, Huang P, Zhao XS, Cheng G, Zhou X, Kaminski HJ, Liu L, Ransohoff RM. Haploinsufficiency of utrophin gene worsens skeletal muscle inflammation and fibrosis in mdx mice. J Neurol Sci 2007; 264:106-11. [PMID: 17889902 PMCID: PMC2696235 DOI: 10.1016/j.jns.2007.08.029] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 07/31/2007] [Accepted: 08/03/2007] [Indexed: 11/30/2022]
Abstract
To address whether mdx mice with haploinsufficiency of utrophin (mdx/utrn+/-) develop more severe skeletal muscle inflammation and fibrosis than mdx mice, to represent a better model for Duchenne muscular dystrophy (DMD), we performed qualitative and quantitative analysis of skeletal muscle inflammation and fibrosis in mdx and mdx/utrn+/- littermates. Inflammation was significantly worse in mdx/utrn+/- quadriceps at age 3 and 6 months and in mdx/utrn+/- diaphragm at age 3 but not 6 months. Fibrosis was more severe in mdx/utrn+/- diaphragm at 6 months, and at this age, mild fibrosis was noted in quadriceps of mdx/utrn+/- but not mdx mice. The findings indicate that utrophin compensates, although insufficiently, for the effects of dystrophin loss with regard to inflammation and fibrosis of both quadriceps and diaphragm muscles in mdx mice. With more severe muscle dystrophy than mdx mice and a longer life span than utrophin-dystrophin-deficient (dko) mice, mdx/utrn+/- mice provide a better mouse model for testing potential therapies for muscle inflammation and fibrosis associated with DMD.
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Affiliation(s)
- Lan Zhou
- Department of Neurology, Cleveland Clinic, Cleveland, OH 44195, USA.
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85
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Mattei E, Corbi N, Di Certo MG, Strimpakos G, Severini C, Onori A, Desantis A, Libri V, Buontempo S, Floridi A, Fanciulli M, Baban D, Davies KE, Passananti C. Utrophin up-regulation by an artificial transcription factor in transgenic mice. PLoS One 2007; 2:e774. [PMID: 17712422 PMCID: PMC1942121 DOI: 10.1371/journal.pone.0000774] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 07/23/2007] [Indexed: 12/27/2022] Open
Abstract
Duchenne Muscular Dystrophy (DMD) is a severe muscle degenerative disease, due to absence of dystrophin. There is currently no effective treatment for DMD. Our aim is to up-regulate the expression level of the dystrophin related gene utrophin in DMD, complementing in this way the lack of dystrophin functions. To this end we designed and engineered several synthetic zinc finger based transcription factors. In particular, we have previously shown that the artificial three zinc finger protein named Jazz, fused with the appropriate effector domain, is able to drive the transcription of a test gene from the utrophin promoter “A”. Here we report on the characterization of Vp16-Jazz-transgenic mice that specifically over-express the utrophin gene at the muscular level. A Chromatin Immunoprecipitation assay (ChIP) demonstrated the effective access/binding of the Jazz protein to active chromatin in mouse muscle and Vp16-Jazz was shown to be able to up-regulate endogenous utrophin gene expression by immunohistochemistry, western blot analyses and real-time PCR. To our knowledge, this is the first example of a transgenic mouse expressing an artificial gene coding for a zinc finger based transcription factor. The achievement of Vp16-Jazz transgenic mice validates the strategy of transcriptional targeting of endogenous genes and could represent an exclusive animal model for use in drug discovery and therapeutics.
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Affiliation(s)
- Elisabetta Mattei
- Istituto di Neurobiologia e Medicina Molecolare, Consiglio Nazionale delle Ricerche, European Brain Research Institute, Rome, Italy
- Italian Association for Cancer Research, Roman Oncogenomic Center, Rome, Italy
| | - Nicoletta Corbi
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Regina Elena Cancer Institute, Rome, Italy
| | - Maria Grazia Di Certo
- Istituto di Neurobiologia e Medicina Molecolare, Consiglio Nazionale delle Ricerche, European Brain Research Institute, Rome, Italy
- Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy
| | - Georgios Strimpakos
- Istituto di Neurobiologia e Medicina Molecolare, Consiglio Nazionale delle Ricerche, European Brain Research Institute, Rome, Italy
| | - Cinzia Severini
- Istituto di Neurobiologia e Medicina Molecolare, Consiglio Nazionale delle Ricerche, European Brain Research Institute, Rome, Italy
| | - Annalisa Onori
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Regina Elena Cancer Institute, Rome, Italy
| | - Agata Desantis
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Regina Elena Cancer Institute, Rome, Italy
- Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy
| | - Valentina Libri
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Regina Elena Cancer Institute, Rome, Italy
| | - Serena Buontempo
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Regina Elena Cancer Institute, Rome, Italy
| | - Aristide Floridi
- Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy
- Laboratory B, Regina Elena Cancer Institute, Rome, Italy
| | - Maurizio Fanciulli
- Italian Association for Cancer Research, Roman Oncogenomic Center, Rome, Italy
- Laboratory B, Regina Elena Cancer Institute, Rome, Italy
| | - Dilair Baban
- Department of Physiology, Anatomy and Genetics, Medical Research Council Functional Genetics Unit, University of Oxford, Oxford, United Kingdom
| | - Kay E. Davies
- Department of Physiology, Anatomy and Genetics, Medical Research Council Functional Genetics Unit, University of Oxford, Oxford, United Kingdom
| | - Claudio Passananti
- Italian Association for Cancer Research, Roman Oncogenomic Center, Rome, Italy
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Regina Elena Cancer Institute, Rome, Italy
- * To whom correspondence should be addressed. E-mail:
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86
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Townsend D, Blankinship MJ, Allen JM, Gregorevic P, Chamberlain JS, Metzger JM. Systemic administration of micro-dystrophin restores cardiac geometry and prevents dobutamine-induced cardiac pump failure. Mol Ther 2007; 15:1086-92. [PMID: 17440445 DOI: 10.1038/sj.mt.6300144] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a fatal disease of striated muscle deterioration resulting from the loss of the cytoskeletal protein dystrophin. Most patients develop significant cardiomyopathy, with heart failure being the second leading cause of death in DMD. Compared with the extensive studies on skeletal muscle defects and potential therapy in DMD, very little attention has been directed at the increasing incidence of heart failure in DMD. Here we show that a single systemic injection of recombinant adeno-associated virus (rAAV2/6) harboring micro-dystrophin leads to extensive cardiac transduction, with micro-dystrophin correctly localized at the periphery of the cardiac myocytes and functionally associated with the sarcolemmal membrane. Significantly, micro-dystrophin gene transfer corrected the baseline end-diastolic volume defect in the mdx mouse heart and prevented cardiac pump failure induced by dobutamine stress testing in vivo, although several parameters of systolic function were not corrected. These results demonstrate that systemic gene delivery of micro-dystrophin can restore ventricular distensibility and protect the mdx myocardium from pump dysfunction during adrenergic stimulation in vivo.
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Affiliation(s)
- DeWayne Townsend
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA.
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87
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Duan D. Challenges and opportunities in dystrophin-deficient cardiomyopathy gene therapy. Hum Mol Genet 2006; 15 Spec No 2:R253-61. [PMID: 16987891 PMCID: PMC2581718 DOI: 10.1093/hmg/ddl180] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The last decade has evidenced unprecedented progress in gene therapy of Duchenne and Becker muscular dystrophy (DMD and BMD) skeletal muscle disease. Cardiomyopathy is a leading cause of morbidity and mortality in both patients and carriers of DMD, BMD and X-linked dilated cardiomyopathy. However, there is little advance in heart gene therapy. The gene, the vector, vector delivery, the target tissue and animal models are five fundamental components in developing an effective gene therapy. Intensive effort has been made in optimizing gene transfer vectors and methods. Systemic and/or local delivery of recombinant adeno-associated viral vector have resulted in widespread transduction in the rodent heart. The current challenge is to define other parameters that are essential for a successful gene therapy such as the best candidate gene(s), the optimal expression level and the target tissue. This review focuses on these long-ignored aspects and points out future research directions. In particular, we need to address whether all or only some of the recently developed mini- and microgenes are protective in the heart, whether partial correction can lead to whole heart function improvement, whether over-expression is hazardous and whether correcting skeletal muscle disease can slow down or stop the progression of cardiomyopathy. Discussion is also made on whether the current mouse models can meet these research needs.
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Affiliation(s)
- Dongsheng Duan
- Department of Molecular Microbiology and Immunology, The University of Missouri School of Medicine, One Hospital Dr., Room M610G, MSB Columbia, MO 65212, USA.
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