1
|
Riddell DO, Hildyard JCW, Harron RCM, Taylor-Brown F, Kornegay JN, Wells DJ, Piercy RJ. Longitudinal assessment of skeletal muscle functional mechanics in the DE50-MD dog model of Duchenne muscular dystrophy. Dis Model Mech 2023; 16:dmm050395. [PMID: 38050706 PMCID: PMC10753191 DOI: 10.1242/dmm.050395] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 11/29/2023] [Indexed: 12/06/2023] Open
Abstract
Duchenne muscular dystrophy (DMD), caused by mutations in the dystrophin (DMD) gene, is associated with fatal muscle degeneration and atrophy. Patients with DMD have progressive reductions in skeletal muscle strength and resistance to eccentric muscle stretch. Using the DE50-MD dog model of DMD, we assessed tibiotarsal joint (TTJ) flexor and extensor force dynamics, and the resistance of dystrophic muscle to eccentric stretch. Male DE50-MD and wild-type (WT) dogs were analysed every 3 months until 18 months of age. There was an age-associated decline in eccentric contraction resistance in DE50-MD TTJ flexors that discriminated, with high statistical power, WT from DE50-MD individuals. For isometric contraction, at the majority of timepoints, DE50-MD dogs had lower maximum absolute and relative TTJ flexor force, reduced TTJ muscle contraction times and prolonged relaxation compared to those in WT dogs. Cranial tibial muscles, the primary TTJ flexor, of 18-month-old DE50-MD dogs had significant numbers of regenerating fibres as expected, but also fewer type I fibres and more hybrid fibres than those in WT dogs. We conclude that these parameters, in particular, the eccentric contraction decrement, could be used as objective outcome measures for pre-clinical assessment in DE50-MD dogs.
Collapse
Affiliation(s)
- Dominique O. Riddell
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Science and Services, Royal Veterinary College, London NW10TU, UK
| | - John C. W. Hildyard
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Science and Services, Royal Veterinary College, London NW10TU, UK
| | - Rachel C. M. Harron
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Science and Services, Royal Veterinary College, London NW10TU, UK
| | - Frances Taylor-Brown
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Science and Services, Royal Veterinary College, London NW10TU, UK
| | - Joe N. Kornegay
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX 77843, USA
| | - Dominic J. Wells
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London NW10TU, UK
| | - Richard J. Piercy
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Science and Services, Royal Veterinary College, London NW10TU, UK
| |
Collapse
|
2
|
Birch SM, Lawlor MW, Conlon TJ, Guo LJ, Crudele JM, Hawkins EC, Nghiem PP, Ahn M, Meng H, Beatka MJ, Fickau BA, Prieto JC, Styner MA, Struharik MJ, Shanks C, Brown KJ, Golebiowski D, Bettis AK, Balog-Alvarez CJ, Clement N, Coleman KE, Corti M, Pan X, Hauschka SD, Gonzalez JP, Morris CA, Schneider JS, Duan D, Chamberlain JS, Byrne BJ, Kornegay JN. Assessment of systemic AAV-microdystrophin gene therapy in the GRMD model of Duchenne muscular dystrophy. Sci Transl Med 2023; 15:eabo1815. [PMID: 36599002 PMCID: PMC11107748 DOI: 10.1126/scitranslmed.abo1815] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 12/09/2022] [Indexed: 01/06/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a progressive muscle wasting disease caused by the absence of dystrophin, a membrane-stabilizing protein encoded by the DMD gene. Although mouse models of DMD provide insight into the potential of a corrective therapy, data from genetically homologous large animals, such as the dystrophin-deficient golden retriever muscular dystrophy (GRMD) model, may more readily translate to humans. To evaluate the clinical translatability of an adeno-associated virus serotype 9 vector (AAV9)-microdystrophin (μDys5) construct, we performed a blinded, placebo-controlled study in which 12 GRMD dogs were divided among four dose groups [control, 1 × 1013 vector genomes per kilogram (vg/kg), 1 × 1014 vg/kg, and 2 × 1014 vg/kg; n = 3 each], treated intravenously at 3 months of age with a canine codon-optimized microdystrophin construct, rAAV9-CK8e-c-μDys5, and followed for 90 days after dosing. All dogs received prednisone (1 milligram/kilogram) for a total of 5 weeks from day -7 through day 28. We observed dose-dependent increases in tissue vector genome copy numbers; μDys5 protein in multiple appendicular muscles, the diaphragm, and heart; limb and respiratory muscle functional improvement; and reduction of histopathologic lesions. As expected, given that a truncated dystrophin protein was generated, phenotypic test results and histopathologic lesions did not fully normalize. All administrations were well tolerated, and adverse events were not seen. These data suggest that systemically administered AAV-microdystrophin may be dosed safely and could provide therapeutic benefit for patients with DMD.
Collapse
Affiliation(s)
- Sharla M. Birch
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX; 77843
| | | | - Thomas J. Conlon
- University of Florida, Powell Gene Therapy Center, Gainesville, FL; 32610
| | - Lee-Jae Guo
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX; 77843
| | | | - Eleanor C. Hawkins
- North Carolina State University, College of Veterinary Medicine, Raleigh, NC; 27606
| | - Peter P. Nghiem
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX; 77843
| | - Mihye Ahn
- University of Nevada-Reno, Reno, NV; 89557
| | - Hui Meng
- Medical College of Wisconsin, Milwaukee, WI; 53226
| | | | | | | | | | | | | | | | | | - Amanda K. Bettis
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX; 77843
| | - Cynthia J. Balog-Alvarez
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX; 77843
| | - Nathalie Clement
- University of Florida, Powell Gene Therapy Center, Gainesville, FL; 32610
| | - Kirsten E. Coleman
- University of Florida, Powell Gene Therapy Center, Gainesville, FL; 32610
| | - Manuela Corti
- University of Florida, Powell Gene Therapy Center, Gainesville, FL; 32610
| | - Xiufang Pan
- University of Missouri, School of Medicine, Columbia, MO 65212
| | | | | | | | | | - Dongsheng Duan
- University of Missouri, School of Medicine, Columbia, MO 65212
| | | | - Barry J. Byrne
- University of Florida, Powell Gene Therapy Center, Gainesville, FL; 32610
| | - Joe. N. Kornegay
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX; 77843
| |
Collapse
|
3
|
Hakim CH, Teixeira J, Leach SB, Duan D. Physiological Assessment of Muscle, Heart, and Whole Body Function in the Canine Model of Duchenne Muscular Dystrophy. Methods Mol Biol 2023; 2587:67-103. [PMID: 36401025 DOI: 10.1007/978-1-0716-2772-3_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a lethal muscle disease caused by dystrophin deficiency. Patients gradually lose motor function, become wheelchair-bound, and die from respiratory and/or cardiac muscle failure. Dystrophin-null dogs have been used as a large animal model for DMD since 1988 and are considered an excellent bridge between rodent models and human patients. While numerous protocols have been published for studying muscle and heart physiology in mice, few such protocols exist for studying skeletal muscle contractility, heart function, and whole-body activity in dogs. Over the last 20 years, we have developed and adapted an array of assays to evaluate whole-body movement, gait, single muscle force, whole limb torque, cardiac electrophysiology, and hemodynamic function in normal and dystrophic dogs. In this chapter, we present detailed working protocols for these assays and lessons we learned during the development and use of these protocols.
Collapse
Affiliation(s)
- Chady H Hakim
- Department of Molecular Microbiology and Immunology, School of Medicine, The University of Missouri, Columbia, MO, USA
| | - James Teixeira
- Department of Molecular Microbiology and Immunology, School of Medicine, The University of Missouri, Columbia, MO, USA
| | - Stacy B Leach
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, The University of Missouri, Columbia, MO, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine, The University of Missouri, Columbia, MO, USA.
- Department of Biomedical, Biological & Chemical Engineering, College of Engineering, The University of Missouri, Columbia, MO, USA.
- Department of Neurology, School of Medicine, The University of Missouri, Columbia, MO, USA.
- Department of Biomedical Sciences, College of Veterinary Medicine, The University of Missouri, Columbia, MO, USA.
| |
Collapse
|
4
|
Stirm M, Fonteyne LM, Shashikadze B, Stöckl JB, Kurome M, Keßler B, Zakhartchenko V, Kemter E, Blum H, Arnold GJ, Matiasek K, Wanke R, Wurst W, Nagashima H, Knieling F, Walter MC, Kupatt C, Fröhlich T, Klymiuk N, Blutke A, Wolf E. Pig models for Duchenne muscular dystrophy – from disease mechanisms to validation of new diagnostic and therapeutic concepts. Neuromuscul Disord 2022; 32:543-556. [DOI: 10.1016/j.nmd.2022.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/22/2022] [Accepted: 04/22/2022] [Indexed: 12/13/2022]
|
5
|
Kuraoka M, Aoki Y, Takeda S. Development of outcome measures according to dystrophic phenotypes in canine X-linked muscular dystrophy in Japan. Exp Anim 2021; 70:419-430. [PMID: 34135266 PMCID: PMC8614006 DOI: 10.1538/expanim.21-0072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked lethal muscle disorder characterized by primary muscle degeneration. Therapeutic strategies for DMD have been extensively explored, and some are in the stage of human clinical trials. Along with the development of new therapies, sensitive outcome measures are needed to monitor the effects of new treatments. Therefore, we investigated outcome measures such as biomarkers and motor function evaluation in a dystrophic model of beagle dogs, canine X-linked muscular dystrophy in Japan (CXMDJ). Osteopontin (OPN), a myogenic inflammatory cytokine, was explored as a potential biomarker in dystrophic dogs over the disease course. The serum OPN levels of CXMDJ dystrophic dogs were elevated, even in the early disease phase, and this could be related to the presence of regenerating muscle fibers; as such, OPN would be a promising biomarker for muscle regeneration. Next, accelerometry, which is an efficient method to quantify performance in validated tasks, was used to evaluate motor function longitudinally in dystrophic dogs. We measured three-axis acceleration and angular velocity with wireless hybrid sensors during gait evaluations. Multiple parameters of acceleration and angular velocity showed notedly lower values in dystrophic dogs compared with wild-type dogs, even at the onset of muscle weakness. These parameters accordingly decreased with exacerbation of clinical manifestations along with the disease course. Multiple parameters also indicated gait abnormalities in dystrophic dogs, such as a waddling gait. These outcome measures could be applicable in clinical trials of patients with DMD or other muscle disorders.
Collapse
Affiliation(s)
- Mutsuki Kuraoka
- Laboratory of Experimental Animal Science, Nippon Veterinary and Life Science University.,Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry
| | - Yoshitsugu Aoki
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry
| | - Shin'ichi Takeda
- National Institute of Neuroscience, National Center of Neurology and Psychiatry
| |
Collapse
|
6
|
Martin PT, Zygmunt DA, Ashbrook A, Hamilton S, Packer D, Birch SM, Bettis AK, Balog-Alvarez CJ, Guo LJ, Nghiem PP, Kornegay JN. Short-term treatment of golden retriever muscular dystrophy (GRMD) dogs with rAAVrh74.MHCK7.GALGT2 induces muscle glycosylation and utrophin expression but has no significant effect on muscle strength. PLoS One 2021; 16:e0248721. [PMID: 33770101 PMCID: PMC7997012 DOI: 10.1371/journal.pone.0248721] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 03/03/2021] [Indexed: 11/30/2022] Open
Abstract
We have examined the effects of intravenous (IV) delivery of rAAVrh74.MHCK7.GALGT2 in the golden retriever muscular dystrophy (GRMD) model of Duchenne Muscular Dystrophy (DMD). After baseline testing, GRMD dogs were treated at 3 months of age and reassessed at 6 months. This 3–6 month age range is a period of rapid disease progression, thus offering a relatively short window to establish treatment efficacy. Measures analyzed included muscle AAV transduction, GALGT2 transgene expression, GALGT2-induced glycosylation, muscle pathology, and muscle function. A total of five dogs were treated, 4 at 2x1014vg/kg and one at 6x1014vgkg. The 2x1014vg/kg dose led to transduction of regions of the heart with 1–3 vector genomes (vg) per nucleus, while most skeletal muscles were transduced with 0.25–0.5vg/nucleus. GALGT2-induced glycosylation paralleled levels of myofiber vg transduction, with about 90% of cardiomyocytes having increased glycosylation versus 20–35% of all myofibers across the skeletal muscles tested. Conclusions from phenotypic testing were limited by the small number of dogs. Treated dogs had less pronounced fibrosis and overall lesion severity when compared to control groups, but surprisingly no significant changes in limb muscle function measures. GALGT2-treated skeletal muscle and heart had elevated levels of utrophin protein expression and GALGT2-induced expression of glycosylated α dystroglycan, providing further evidence of a treatment effect. Serum chemistry, hematology, and cardiac function measures were largely unchanged by treatment. Cumulatively, these data show that short-term intravenous treatment of GRMD dogs with rAAVrh74.MHCK7.GALGT2 at high doses can induce muscle glycosylation and utrophin expression and may be safe over a short 3-month interval, but that such treatments had only modest effects on muscle pathology and did not significantly improve muscle strength.
Collapse
Affiliation(s)
- Paul T. Martin
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, United States of America
- * E-mail:
| | - Deborah A. Zygmunt
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, Ohio, United States of America
| | - Anna Ashbrook
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, Ohio, United States of America
| | - Sonia Hamilton
- Neuroscience Undergraduate Program, The Ohio State University, Columbus, Ohio, United States of America
| | - Davin Packer
- Neuroscience Graduate Program, The Ohio State University, Columbus, Ohio, United States of America
| | - Sharla M. Birch
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| | - Amanda K. Bettis
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| | - Cynthia J. Balog-Alvarez
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| | - Lee-Jae Guo
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| | - Peter P. Nghiem
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| | - Joe N. Kornegay
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| |
Collapse
|
7
|
Hawkins EC, Bettis AK, Kornegay JN. Expiratory dysfunction in young dogs with golden retriever muscular dystrophy. Neuromuscul Disord 2020; 30:930-937. [PMID: 33071066 PMCID: PMC7680419 DOI: 10.1016/j.nmd.2020.09.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 11/25/2022]
Abstract
Respiratory disease is a leading cause of morbidity in people with Duchenne muscular dystrophy and also occurs in the golden retriever muscular dystrophy (GRMD) model. We have previously shown that adult GRMD dogs have elevated expiratory flow as measured non-invasively during tidal breathing. This abnormality likely results from increased chest and diaphragmatic recoil associated with fibrosis and remodeling. Treatments must reverse pathologic effects on the diaphragm and other respiratory muscles to maximally reduce disease morbidity and mortality. Here, we extended our work in adults to younger GRMD dogs to define parameters that would be helpful in preclinical trials. Tidal breathing spirometry and respiratory inductance plethysmography were performed in GRMD dogs at approximately 3 and 6 months of age, corresponding to approximately 5-10 years in DMD, when clinical trials are often conducted. Expiratory flows were markedly elevated in GRMD versus normal dogs at 6 months. Values increased in GRMD dogs between 3 and 6 months, providing a 3-month window to assess treatment efficacy. These changes in breathing mechanics have not been previously identified at such an early age. Expiratory flow measured during tidal breathing of unsedated young GRMD dogs could be a valuable marker of respiratory mechanics during preclinical trials.
Collapse
Affiliation(s)
- Eleanor C Hawkins
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA.
| | - Amanda K Bettis
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX 77843-4458, USA
| | - Joe N Kornegay
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX 77843-4458, USA
| |
Collapse
|
8
|
Guo LJ, Soslow JH, Bettis AK, Nghiem PP, Cummings KJ, Lenox MW, Miller MW, Kornegay JN, Spurney CF. Natural History of Cardiomyopathy in Adult Dogs With Golden Retriever Muscular Dystrophy. J Am Heart Assoc 2019; 8:e012443. [PMID: 31411085 PMCID: PMC6759898 DOI: 10.1161/jaha.119.012443] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background Duchenne muscular dystrophy (DMD) is an X‐linked disease that causes progressive muscle weakness. Affected boys typically die from respiratory or cardiac failure. Golden retriever muscular dystrophy (GRMD) is genetically homologous with DMD and causes analogous skeletal and cardiac muscle disease. Previous studies have detailed features of GRMD cardiomyopathy in mostly young dogs. Cardiac disease is not well characterized in adult GRMD dogs, and cardiac magnetic resonance (CMR) imaging studies have not been completed. Methods and Results We evaluated echocardiography and CMR in 24 adult GRMD dogs at different ages. Left ventricular systolic and diastolic functions, wall thickness, and myocardial strain were assessed with echocardiography. Features evaluated with CMR included left ventricular function, chamber size, myocardial mass, and late gadolinium enhancement. Our results largely paralleled those of DMD cardiomyopathy. Ejection fraction and fractional shortening correlated well with age, with systolic dysfunction occurring at ≈30 to 45 months. Circumferential strain was more sensitive than ejection fraction in early disease detection. Evidence of left ventricular chamber dilatation provided proof of dilated cardiomyopathy. Late gadolinium enhancement imaging showed DMD‐like left ventricular lateral wall lesions and earlier involvement of the anterior septum. Multiple functional indexes were graded objectively and added, with and without late gadolinium enhancement, to give cardiac and cardiomyopathy scores of disease severity. Consistent with DMD, there was parallel skeletal muscle involvement, as tibiotarsal joint flexion torque declined in tandem with cardiac function. Conclusions This study established parallels of progressive cardiomyopathy between dystrophic dogs and boys, further validating GRMD as a model of DMD cardiac disease.
Collapse
Affiliation(s)
- Lee-Jae Guo
- Department of Veterinary Integrative Biosciences College of Veterinary Medicine and Biomedical Sciences Texas A&M University College Station TX.,Texas A&M Institute for Preclinical Studies College of Veterinary Medicine and Biomedical Sciences Texas A&M University College Station TX
| | - Jonathan H Soslow
- Division of Pediatric Cardiology Department of Pediatrics Vanderbilt University Medical Center Nashville TN
| | - Amanda K Bettis
- Department of Veterinary Integrative Biosciences College of Veterinary Medicine and Biomedical Sciences Texas A&M University College Station TX
| | - Peter P Nghiem
- Department of Veterinary Integrative Biosciences College of Veterinary Medicine and Biomedical Sciences Texas A&M University College Station TX
| | - Kevin J Cummings
- Department of Population Medicine and Diagnostic Sciences College of Veterinary Medicine Cornell University Ithaca NY
| | - Mark W Lenox
- Department of Biomedical Engineering College of Engineering Texas A&M University College Station TX
| | - Matthew W Miller
- Department of Small Animal Clinical Sciences College of Veterinary Medicine and Biomedical Sciences Texas A&M University College Station TX
| | - Joe N Kornegay
- Department of Veterinary Integrative Biosciences College of Veterinary Medicine and Biomedical Sciences Texas A&M University College Station TX
| | - Christopher F Spurney
- Division of Cardiology and Center for Genetic Medicine Research Children's National Health System Washington DC
| |
Collapse
|
9
|
Schneider SM, Sridhar V, Bettis AK, Heath-Barnett H, Balog-Alvarez CJ, Guo LJ, Johnson R, Jaques S, Vitha S, Glowcwski AC, Kornegay JN, Nghiem PP. Glucose Metabolism as a Pre-clinical Biomarker for the Golden Retriever Model of Duchenne Muscular Dystrophy. Mol Imaging Biol 2019; 20:780-788. [PMID: 29508262 PMCID: PMC6153676 DOI: 10.1007/s11307-018-1174-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Purpose Metabolic dysfunction in Duchenne muscular dystrophy (DMD) is characterized by reduced glycolytic and oxidative enzymes, decreased and abnormal mitochondria, decreased ATP, and increased oxidative stress. We analyzed glucose metabolism as a potential disease biomarker in the genetically homologous golden retriever muscular dystrophy (GRMD) dog with molecular, biochemical, and in vivo imaging. Procedures Pelvic limb skeletal muscle and left ventricle tissue from the heart were analyzed by mRNA profiling, qPCR, western blotting, and immunofluorescence microscopy for the primary glucose transporter (GLUT4). Physiologic glucose handling was measured by fasting glucose tolerance test (GTT), insulin levels, and skeletal and cardiac positron emission tomography/X-ray computed tomography (PET/CT) using the glucose analog 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG). Results MRNA profiles showed decreased GLUT4 in the cranial sartorius (CS), vastus lateralis (VL), and long digital extensor (LDE) of GRMD vs. normal dogs. QPCR confirmed GLUT4 downregulation but increased hexokinase-1. GLUT4 protein levels were not different in the CS, VL, or left ventricle but increased in the LDE of GRMD vs. normal. Microscopy revealed diffuse membrane expression of GLUT4 in GRMD skeletal but not cardiac muscle. GTT showed higher basal glucose and insulin in GRMD but rapid tissue glucose uptake at 5 min post-dextrose injection in GRMD vs. normal/carrier dogs. PET/ CT with [18F]FDG and simultaneous insulin stimulation showed a significant increase (p = 0.03) in mean standard uptake values (SUV) in GRMD skeletal muscle but not pelvic fat at 5 min post-[18F]FDG /insulin injection. Conversely, mean cardiac SUV was lower in GRMD than carrier/normal (p < 0.01). Conclusions Altered glucose metabolism in skeletal and cardiac muscle of GRMD dogs can be monitored with molecular, biochemical, and in vivo imaging studies and potentially utilized as a biomarker for disease progression and therapeutic response. Electronic supplementary material The online version of this article (10.1007/s11307-018-1174-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Sarah Morar Schneider
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Vidya Sridhar
- Texas A&M Institute for Preclinical Studies, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Amanda K Bettis
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843-4458, USA
| | - Heather Heath-Barnett
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843-4458, USA
| | - Cynthia J Balog-Alvarez
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843-4458, USA
| | - Lee-Jae Guo
- Texas A&M Institute for Preclinical Studies, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA.,Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843-4458, USA
| | - Rachel Johnson
- Texas A&M Institute for Preclinical Studies, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Scott Jaques
- Texas A&M Veterinary Diagnostic Laboratory, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Stanislav Vitha
- Microscopy Imaging Center, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Alan C Glowcwski
- Texas A&M Institute for Preclinical Studies, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Joe N Kornegay
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843-4458, USA
| | - Peter P Nghiem
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843-4458, USA.
| |
Collapse
|
10
|
van Putten M, Aartsma-Rus A, Grounds MD, Kornegay JN, Mayhew A, Gillingwater TH, Takeda S, Rüegg MA, De Luca A, Nagaraju K, Willmann R. Update on Standard Operating Procedures in Preclinical Research for DMD and SMA Report of TREAT-NMD Alliance Workshop, Schiphol Airport, 26 April 2015, The Netherlands. J Neuromuscul Dis 2018; 5:29-34. [PMID: 29480217 PMCID: PMC5836406 DOI: 10.3233/jnd-170288] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A workshop took place in 2015 to follow up TREAT-NMD activities dedicated to improving quality in the preclinical phase of drug development for neuromuscular diseases. In particular, this workshop adressed necessary future steps regarding common standard experimental protocols and the issue of improving the translatability of preclinical efficacy studies.
Collapse
Affiliation(s)
- Maaike van Putten
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Miranda D Grounds
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Perth, WA, Australia
| | - Joe N Kornegay
- College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TX, USA
| | - Anna Mayhew
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Shin'ichi Takeda
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | | | - Annamaria De Luca
- Department of Pharmacy and Drug Sciences, Unit of Pharmacology, University of Bari, Bari, Italy
| | | | - Raffaella Willmann
- Biozentrum, University of Basel, Basel, Switzerland.,Swiss Foundation for Research on Muscle Diseases, Cortaillod, Switzerland
| |
Collapse
|
11
|
Stoughton WB, Li J, Balog-Alvarez C, Kornegay JN. Impaired autophagy correlates with golden retriever muscular dystrophy phenotype. Muscle Nerve 2018. [DOI: 10.1002/mus.26121] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- William B. Stoughton
- Department of Veterinary Integrative Biosciences; Texas A&M University College of Veterinary Medicine and Biomedical Sciences; College Station Texas 77843 USA
| | - Jianrong Li
- Department of Veterinary Integrative Biosciences; Texas A&M University College of Veterinary Medicine and Biomedical Sciences; College Station Texas 77843 USA
| | - Cindy Balog-Alvarez
- Department of Veterinary Integrative Biosciences; Texas A&M University College of Veterinary Medicine and Biomedical Sciences; College Station Texas 77843 USA
| | - Joe N. Kornegay
- Department of Veterinary Integrative Biosciences; Texas A&M University College of Veterinary Medicine and Biomedical Sciences; College Station Texas 77843 USA
| |
Collapse
|
12
|
Expression profiling of disease progression in canine model of Duchenne muscular dystrophy. PLoS One 2018; 13:e0194485. [PMID: 29554127 PMCID: PMC5858769 DOI: 10.1371/journal.pone.0194485] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 03/05/2018] [Indexed: 12/17/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) causes progressive disability in 1 of every 5,000 boys due to the lack of functional dystrophin protein. Despite much advancement in knowledge about DMD disease presentation and progression—attributable in part to studies using mouse and canine models of the disease–current DMD treatments are not equally effective in all patients. There remains, therefore, a need for translational animal models in which novel treatment targets can be identified and evaluated. Golden Retriever muscular dystrophy (GRMD) is a phenotypically and genetically homologous animal model of DMD. As with DMD, speed of disease progression in GRMD varies substantially. However, unlike DMD, all GRMD dogs possess the same causal mutation; therefore genetic modifiers of phenotypic variation are relatively easier to identify. Furthermore, the GRMD dogs used in this study reside within the same colony, reducing the confounding effects of environment on phenotypic variation. To detect modifiers of disease progression, we developed gene expression profiles using RNA sequencing for 9 dogs: 6 GRMD dogs (3 with faster-progressing and 3 with slower-progressing disease, based on quantitative, objective biomarkers) and 3 control dogs from the same colony. All dogs were evaluated at 2 time points: early disease onset (3 months of age) and the point at which GRMD stabilizes (6 months of age) using quantitative, objective biomarkers identified as robust against the effects of relatedness/inbreeding. Across all comparisons, the most differentially expressed genes fell into 3 categories: myogenesis/muscle regeneration, metabolism, and inflammation. Our findings are largely in concordance with DMD and mouse model studies, reinforcing the utility of GRMD as a translational model. Novel findings include the strong up-regulation of chitinase 3-like 1 (CHI3L1) in faster-progressing GRMD dogs, suggesting previously unexplored mechanisms underlie progression speed in GRMD and DMD. In summary, our findings support the utility of RNA sequencing for evaluating potential biomarkers of GRMD progression speed, and are valuable for identifying new avenues of exploration in DMD research.
Collapse
|
13
|
Nghiem PP, Kornegay JN, Uaesoontrachoon K, Bello L, Yin Y, Kesari A, Mittal P, Schatzberg SJ, Many GM, Lee NH, Hoffman EP. Osteopontin is linked with AKT, FoxO1, and myostatin in skeletal muscle cells. Muscle Nerve 2017; 56:1119-1127. [PMID: 28745831 PMCID: PMC5690863 DOI: 10.1002/mus.25752] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 07/10/2017] [Accepted: 07/23/2017] [Indexed: 01/17/2023]
Abstract
Introduction: Osteopontin (OPN) polymorphisms are associated with muscle size and modify disease progression in Duchenne muscular dystrophy (DMD). We hypothesized that OPN may share a molecular network with myostatin (MSTN). Methods: Studies were conducted in the golden retriever (GRMD) and mdx mouse models of DMD. Follow‐up in‐vitro studies were employed in myogenic cells and the mdx mouse treated with recombinant mouse (rm) or human (Hu) OPN protein. Results: OPN was increased and MSTN was decreased and levels correlated inversely in GRMD hypertrophied muscle. RM‐OPN treatment led to induced AKT1 and FoxO1 phosphorylation, microRNA‐486 modulation, and decreased MSTN. An AKT1 inhibitor blocked these effects, whereas an RGD‐mutant OPN protein and an RGDS blocking peptide showed similar effects to the AKT inhibitor. RMOPN induced myotube hypertrophy and minimal Feret diameter in mdx muscle. Discussion: OPN may interact with AKT1/MSTN/FoxO1 to modify normal and dystrophic muscle. Muscle Nerve56: 1119–1127, 2017
Collapse
Affiliation(s)
- Peter P Nghiem
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, 4458 TAMU, Texas A&M University, College Station, Texas, 77843-4458, USA
| | - Joe N Kornegay
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, 4458 TAMU, Texas A&M University, College Station, Texas, 77843-4458, USA
| | | | - Luca Bello
- Department of Neurosciences, University of Padova, Padova, Italy
| | - Ying Yin
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Akanchha Kesari
- Department of Human Genetics, Emory University, Atlanta, Georgia, USA
| | - Priya Mittal
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | | | - Gina M Many
- Department of Health Sciences, Central Washington University, Ellensburg, Washington, USA
| | - Norman H Lee
- Department of Pharmacology and Physiology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Eric P Hoffman
- Department of Pharmaceutical Sciences, Binghamton University, State University of New York, Binghamton, New York, USA
| |
Collapse
|
14
|
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked disease caused by mutations in the DMD gene and loss of the protein dystrophin. The absence of dystrophin leads to myofiber membrane fragility and necrosis, with eventual muscle atrophy and contractures. Affected boys typically die in their second or third decade due to either respiratory failure or cardiomyopathy. Despite extensive attempts to develop definitive therapies for DMD, the standard of care remains prednisone, which has only palliative benefits. Animal models, mainly the mdx mouse and golden retriever muscular dystrophy (GRMD) dog, have played a key role in studies of DMD pathogenesis and treatment development. Because the GRMD clinical syndrome is more severe than in mice, better aligning with the progressive course of DMD, canine studies may translate better to humans. The original founder dog for all GRMD colonies worldwide was identified in the early 1980s before the discovery of the DMD gene and dystrophin. Accordingly, analogies to DMD were initially drawn based on similar clinical features, ranging from the X-linked pattern of inheritance to overlapping histopathologic lesions. Confirmation of genetic homology between DMD and GRMD came with identification of the underlying GRMD mutation, a single nucleotide change that leads to exon skipping and an out-of-frame DMD transcript. GRMD colonies have subsequently been established to conduct pathogenetic and preclinical treatment studies. Simultaneous with the onset of GRMD treatment trials, phenotypic biomarkers were developed, allowing definitive characterization of treatment effect. Importantly, GRMD studies have not always substantiated findings from mdx mice and have sometimes identified serious treatment side effects. While the GRMD model may be more clinically relevant than the mdx mouse, usage has been limited by practical considerations related to expense and the number of dogs available. This further complicates ongoing broader concerns about the poor rate of translation of animal model preclinical studies to humans with analogous diseases. Accordingly, in performing GRMD trials, special attention must be paid to experimental design to align with the approach used in DMD clinical trials. This review provides context for the GRMD model, beginning with its original description and extending to its use in preclinical trials.
Collapse
Affiliation(s)
- Joe N Kornegay
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, Mail Stop 4458, College Station, TX, 77843-4458, USA.
| |
Collapse
|
15
|
Nghiem PP, Bello L, Balog-Alvarez C, López SM, Bettis A, Barnett H, Hernandez B, Schatzberg SJ, Piercy RJ, Kornegay JN. Whole genome sequencing reveals a 7 base-pair deletion in DMD exon 42 in a dog with muscular dystrophy. Mamm Genome 2016; 28:106-113. [PMID: 28028563 PMCID: PMC5371640 DOI: 10.1007/s00335-016-9675-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 12/07/2016] [Indexed: 01/03/2023]
Abstract
Dystrophin is a key cytoskeletal protein coded by the Duchenne muscular dystrophy (DMD) gene located on the X-chromosome. Truncating mutations in the DMD gene cause loss of dystrophin and the classical DMD clinical syndrome. Spontaneous DMD gene mutations and associated phenotypes occur in several other species. The mdx mouse model and the golden retriever muscular dystrophy (GRMD) canine model have been used extensively to study DMD disease pathogenesis and show efficacy and side effects of putative treatments. Certain DMD gene mutations in high-risk, the so-called hot spot areas can be particularly helpful in modeling molecular therapies. Identification of specific mutations has been greatly enhanced by new genomic methods. Whole genome, next generation sequencing (WGS) has been recently used to define DMD patient mutations, but has not been used in dystrophic dogs. A dystrophin-deficient Cavalier King Charles Spaniel (CKCS) dog was evaluated at the functional, histopathological, biochemical, and molecular level. The affected dog's phenotype was compared to the previously reported canine dystrophinopathies. WGS was then used to detect a 7 base pair deletion in DMD exon 42 (c.6051-6057delTCTCAAT mRNA), predicting a frameshift in gene transcription and truncation of dystrophin protein translation. The deletion was confirmed with conventional PCR and Sanger sequencing. This mutation is in a secondary DMD gene hotspot area distinct from the one identified earlier at the 5' donor splice site of intron 50 in the CKCS breed.
Collapse
Affiliation(s)
- Peter P Nghiem
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA.
| | - Luca Bello
- Department of Neurosciences, University of Padova, Via Giustiniani 5, 35128, Padova, Italy
| | - Cindy Balog-Alvarez
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Sara Mata López
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Amanda Bettis
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Heather Barnett
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Briana Hernandez
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Scott J Schatzberg
- Veterinary Emergency and Specialty Center of Santa Fe, 2001 Vivigen Way, Santa Fe, NM, 87505, USA
| | - Richard J Piercy
- Department of Clinical Sciences and Services, Royal Veterinary College, London, UK
| | - Joe N Kornegay
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| |
Collapse
|
16
|
Acosta AR, Van Wie E, Stoughton WB, Bettis AK, Barnett HH, LaBrie NR, Balog-Alvarez CJ, Nghiem PP, Cummings KJ, Kornegay JN. Use of the six-minute walk test to characterize golden retriever muscular dystrophy. Neuromuscul Disord 2016; 26:865-872. [PMID: 27818009 DOI: 10.1016/j.nmd.2016.09.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 07/27/2016] [Accepted: 09/28/2016] [Indexed: 12/29/2022]
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder in which loss of the dystrophin protein causes progressive skeletal/cardiac muscle degeneration and death within the third decade. For clinical trials and supportive animal studies, DMD disease progression and response to treatment must be established using outcome parameters (biomarkers). The 6-minute walk test (6MWT), defined as the distance an individual can walk in 6 minutes, is commonly used in DMD clinical trials and has been employed in dogs to characterize cardiac and respiratory disease severity. Building on methods established in DMD and canine clinical studies, we assessed the 6MWT in dogs with the DMD genetic homolog, golden retriever muscular dystrophy (GRMD). Twenty-one cross-bred golden retrievers were categorized as affected (DMD mutation and GRMD phenotype), carrier (female heterozygous for DMD mutation and no phenotype), and normal (wild type DMD gene and normal phenotype). When compared to grouped normal/carrier dogs, GRMD dogs walked shorter height-adjusted distances at 6 and 12 months of age and their distances walked declined with age. Percent change in creatine kinase after 6MWT was greater in GRMD versus normal/carrier dogs at 6 months, providing another potential biomarker. While these data generally support use of the 6MWT as a biomarker for preclinical GRMD treatment trials, there were certain limitations. Results of the 6MWT did not correlate with other outcome parameters for GRMD dogs when considered alone and an 80% increase in mean distance walked would be necessary to achieve satisfactory power.
Collapse
Affiliation(s)
- Austin R Acosta
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843-4458, USA
| | - Emiko Van Wie
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843-4458, USA
| | - William B Stoughton
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843-4458, USA
| | - Amanda K Bettis
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843-4458, USA
| | - Heather H Barnett
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843-4458, USA
| | - Nicholas R LaBrie
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843-4458, USA
| | - Cynthia J Balog-Alvarez
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843-4458, USA
| | - Peter P Nghiem
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843-4458, USA
| | - Kevin J Cummings
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA
| | - Joe N Kornegay
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA; Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843-4458, USA.
| |
Collapse
|
17
|
Brinkmeyer-Langford C, Balog-Alvarez C, Cai JJ, Davis BW, Kornegay JN. Genome-wide association study to identify potential genetic modifiers in a canine model for Duchenne muscular dystrophy. BMC Genomics 2016; 17:665. [PMID: 27549615 PMCID: PMC4994242 DOI: 10.1186/s12864-016-2948-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 07/18/2016] [Indexed: 12/17/2022] Open
Abstract
Background Duchenne muscular dystrophy (DMD) causes progressive muscle degeneration, cardiomyopathy and respiratory failure in approximately 1/5,000 boys. Golden Retriever muscular dystrophy (GRMD) resembles DMD both clinically and pathologically. Like DMD, GRMD exhibits remarkable phenotypic variation among affected dogs, suggesting the influence of modifiers. Understanding the role(s) of genetic modifiers of GRMD may identify genes and pathways that also modify phenotypes in DMD and reveal novel therapies. Therefore, our objective in this study was to identify genetic modifiers that affect discrete GRMD phenotypes. Results We performed a linear mixed-model (LMM) analysis using 16 variably-affected dogs from our GRMD colony (8 dystrophic, 8 non-dystrophic). All of these dogs were either full or half-siblings, and phenotyped for 19 objective, quantitative biomarkers at ages 6 and 12 months. Each biomarker was individually assessed. Gene expression profiles of 59 possible candidate genes were generated for two muscle types: the cranial tibialis and medial head of the gastrocnemius. SNPs significantly associated with GRMD biomarkers were identified on multiple chromosomes (including the X chromosome). Gene expression levels for candidate genes located near these SNPs correlated with biomarker values, suggesting possible roles as GRMD modifiers. Conclusions The results of this study enhance our understanding of GRMD pathology and represent a first step toward the characterization of GRMD modifiers that may be relevant to DMD pathology. Such modifiers are likely to be useful for DMD treatment development based on their relationships to GRMD phenotypes. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2948-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
| | - Cynthia Balog-Alvarez
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| | - James J Cai
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| | - Brian W Davis
- Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Joe N Kornegay
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| |
Collapse
|
18
|
Kornegay JN, Bogan DJ, Bogan JR, Dow JL, Wang J, Fan Z, Liu N, Warsing LC, Grange RW, Ahn M, Balog-Alvarez CJ, Cotten SW, Willis MS, Brinkmeyer-Langford C, Zhu H, Palandra J, Morris CA, Styner MA, Wagner KR. Dystrophin-deficient dogs with reduced myostatin have unequal muscle growth and greater joint contractures. Skelet Muscle 2016; 6:14. [PMID: 27047655 PMCID: PMC4819282 DOI: 10.1186/s13395-016-0085-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/24/2016] [Indexed: 09/02/2023] Open
Abstract
Background Myostatin (Mstn) is a negative regulator of muscle growth whose inhibition promotes muscle growth and regeneration. Dystrophin-deficient mdx mice in which myostatin is knocked out or inhibited postnatally have a less severe phenotype with greater total mass and strength and less fibrosis and fatty replacement of muscles than mdx mice with wild-type myostatin expression. Dogs with golden retriever muscular dystrophy (GRMD) have previously been noted to have increased muscle mass and reduced fibrosis after systemic postnatal myostatin inhibition. Based partly on these results, myostatin inhibitors are in development for use in human muscular dystrophies. However, persisting concerns regarding the effects of long-term and profound myostatin inhibition will not be easily or imminently answered in clinical trials. Methods To address these concerns, we developed a canine (GRippet) model by crossbreeding dystrophin-deficient GRMD dogs with Mstn-heterozygous (Mstn+/−) whippets. A total of four GRippets (dystrophic and Mstn+/−), three GRMD (dystrophic and Mstn wild-type) dogs, and three non-dystrophic controls from two litters were evaluated. Results Myostatin messenger ribonucleic acid (mRNA) and protein levels were downregulated in both GRMD and GRippet dogs. GRippets had more severe postural changes and larger (more restricted) maximal joint flexion angles, apparently due to further exaggeration of disproportionate effects on muscle size. Flexors such as the cranial sartorius were more hypertrophied on magnetic resonance imaging (MRI) in the GRippets, while extensors, including the quadriceps femoris, underwent greater atrophy. Myostatin protein levels negatively correlated with relative cranial sartorius muscle cross-sectional area on MRI, supporting a role in disproportionate muscle size. Activin receptor type IIB (ActRIIB) expression was higher in dystrophic versus control dogs, consistent with physiologic feedback between myostatin and ActRIIB. However, there was no differential expression between GRMD and GRippet dogs. Satellite cell exhaustion was not observed in GRippets up to 3 years of age. Conclusions Partial myostatin loss may exaggerate selective muscle hypertrophy or atrophy/hypoplasia in GRMD dogs and worsen contractures. While muscle imbalance is not a feature of myostatin inhibition in mdx mice, findings in a larger animal model could translate to human experience with myostatin inhibitors. Electronic supplementary material The online version of this article (doi:10.1186/s13395-016-0085-7) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Joe N Kornegay
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458 USA
| | - Daniel J Bogan
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Janet R Bogan
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Jennifer L Dow
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Jiahui Wang
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Zheng Fan
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Naili Liu
- The Hugo W. Moser Research Institute at Kennedy Krieger Institute and Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Leigh C Warsing
- The Hugo W. Moser Research Institute at Kennedy Krieger Institute and Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Robert W Grange
- Department of Human Nutrition, Foods and Exercise, Virginia Tech University, Blacksburg, VA 24061 USA
| | - Mihye Ahn
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Cynthia J Balog-Alvarez
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458 USA
| | - Steven W Cotten
- Department of Pathology, The Ohio State University, Columbus, OH 43210 USA
| | - Monte S Willis
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Candice Brinkmeyer-Langford
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458 USA
| | - Hongtu Zhu
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Joe Palandra
- Rare Disease Research Unit, Pfizer, Inc., Cambridge Park Drive, Cambridge, MA USA
| | - Carl A Morris
- Rare Disease Research Unit, Pfizer, Inc., Cambridge Park Drive, Cambridge, MA USA
| | - Martin A Styner
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Kathryn R Wagner
- The Hugo W. Moser Research Institute at Kennedy Krieger Institute and Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| |
Collapse
|
19
|
Lenhart KC, O'Neill TJ, Cheng Z, Dee R, Demonbreun AR, Li J, Xiao X, McNally EM, Mack CP, Taylor JM. GRAF1 deficiency blunts sarcolemmal injury repair and exacerbates cardiac and skeletal muscle pathology in dystrophin-deficient mice. Skelet Muscle 2015; 5:27. [PMID: 26301073 PMCID: PMC4546166 DOI: 10.1186/s13395-015-0054-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/04/2015] [Indexed: 11/18/2022] Open
Abstract
Background The plasma membranes of striated muscle cells are particularly susceptible to rupture as they endure significant mechanical stress and strain during muscle contraction, and studies have shown that defects in membrane repair can contribute to the progression of muscular dystrophy. The synaptotagmin-related protein, dysferlin, has been implicated in mediating rapid membrane repair through its ability to direct intracellular vesicles to sites of membrane injury. However, further work is required to identify the precise molecular mechanisms that govern dysferlin targeting and membrane repair. We previously showed that the bin–amphiphysin–Rvs (BAR)–pleckstrin homology (PH) domain containing Rho-GAP GTPase regulator associated with focal adhesion kinase-1 (GRAF1) was dynamically recruited to the tips of fusing myoblasts wherein it promoted membrane merging by facilitating ferlin-dependent capturing of intracellular vesicles. Because acute membrane repair responses involve similar vesicle trafficking complexes/events and because our prior studies in GRAF1-deficient tadpoles revealed a putative role for GRAF1 in maintaining muscle membrane integrity, we postulated that GRAF1 might also play an important role in facilitating dysferlin-dependent plasma membrane repair. Methods We used an in vitro laser-injury model to test whether GRAF1 was necessary for efficient muscle membrane repair. We also generated dystrophin/GRAF1 doubledeficient mice by breeding mdx mice with GRAF1 hypomorphic mice. Evans blue dye uptake and extensive morphometric analyses were used to assess sarcolemmal integrity and related pathologies in cardiac and skeletal muscles isolated from these mice. Results Herein, we show that GRAF1 is dynamically recruited to damaged skeletal and cardiac muscle plasma membranes and that GRAF1-depleted muscle cells have reduced membrane healing abilities. Moreover, we show that dystrophin depletion exacerbated muscle damage in GRAF1-deficient mice and that mice with dystrophin/GRAF1 double deficiency phenocopied the severe muscle pathologies observed in dystrophin/dysferlin-double null mice. Consistent with a model that GRAF1 facilitates dysferlin-dependent membrane patching, we found that GRAF1 associates with and regulates plasma membrane deposition of dysferlin. Conclusions Overall, our work indicates that GRAF1 facilitates dysferlin-dependent membrane repair following acute muscle injury. These findings indicate that GRAF1 might play a role in the phenotypic variation and pathological progression of cardiac and skeletal muscle degeneration in muscular dystrophy patients. Electronic supplementary material The online version of this article (doi:10.1186/s13395-015-0054-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Kaitlin C Lenhart
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Thomas J O'Neill
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Zhaokang Cheng
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Rachel Dee
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Alexis R Demonbreun
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611 USA
| | - Jianbin Li
- Department of Gene Therapy Molecular Pharmaceutics, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Xiao Xiao
- Department of Gene Therapy Molecular Pharmaceutics, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Elizabeth M McNally
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611 USA
| | - Christopher P Mack
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Joan M Taylor
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| |
Collapse
|
20
|
Duddy W, Duguez S, Johnston H, Cohen TV, Phadke A, Gordish-Dressman H, Nagaraju K, Gnocchi V, Low S, Partridge T. Muscular dystrophy in the mdx mouse is a severe myopathy compounded by hypotrophy, hypertrophy and hyperplasia. Skelet Muscle 2015; 5:16. [PMID: 25987977 PMCID: PMC4434871 DOI: 10.1186/s13395-015-0041-y] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 04/16/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Preclinical testing of potential therapies for Duchenne muscular dystrophy (DMD) is conducted predominantly of the mdx mouse. But lack of a detailed quantitative description of the pathology of this animal limits our ability to evaluate the effectiveness of putative therapies or their relevance to DMD. METHODS Accordingly, we have measured the main cellular components of muscle growth and regeneration over the period of postnatal growth and early pathology in mdx and wild-type (WT) mice; phalloidin binding is used as a measure of fibre size, myonuclear counts and BrdU labelling as records of myogenic activity. RESULTS We confirm a two-phase postnatal growth pattern in WT muscle: first, increase in myonuclear number over weeks 1 to 3, then expansion of myonuclear domain. Mdx muscle growth lags behind that of WT prior to overt signs of pathology. Fibres are smaller, with fewer myonuclei and smaller myonuclear domains. Moreover, satellite cells are more readily detached from mdx than WT muscle fibres. At 3 weeks, mdx muscles enter a phase of florid myonecrosis, accompanied by concurrent regeneration of an intensity that results in complete replacement of pre-existing muscle over the succeeding 3 to 4 weeks. Both WT and mdx muscles attain maximum size by 12 to 14 weeks, mdx muscle fibres being up to 50% larger than those of WT as they become increasingly branched. Mdx muscle fibres also become hypernucleated, containing twice as many myonuclei per sarcoplasmic volume, as those of WT, the excess corresponding to the number of centrally placed myonuclei. CONCLUSIONS The best-known consequence of lack of dystrophin that is common to DMD and the mdx mouse is the conspicuous necrosis and regeneration of muscle fibres. We present protocols for measuring this in terms both of loss of muscle nuclei previously labelled with BrdU and of the intensity of myonuclear labelling with BrdU administered during the regeneration period. Both measurements can be used to assess the efficacy of putative antinecrotic agents. We also show that lack of dystrophin is associated with a number of previously unsuspected abnormalities of muscle fibre structure and function that do not appear to be directly associated with myonecrosis.
Collapse
Affiliation(s)
- William Duddy
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington DC, 20010 USA ; Myology Center of Research, Institut de Myologie Pitié-Salpétrière - Bâtiment Babinski, 75651 Paris Cedex 13, France
| | - Stephanie Duguez
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington DC, 20010 USA ; Myology Center of Research, Institut de Myologie Pitié-Salpétrière - Bâtiment Babinski, 75651 Paris Cedex 13, France
| | - Helen Johnston
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington DC, 20010 USA
| | - Tatiana V Cohen
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington DC, 20010 USA ; Center for Genetic Muscle Disorders, Kennedy Krieger Institute, 801 N. Broadway, Baltimore, MD 21205 USA
| | - Aditi Phadke
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington DC, 20010 USA
| | - Heather Gordish-Dressman
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington DC, 20010 USA
| | - Kanneboyina Nagaraju
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington DC, 20010 USA
| | - Viola Gnocchi
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington DC, 20010 USA
| | - SiewHui Low
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218 USA
| | - Terence Partridge
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington DC, 20010 USA
| |
Collapse
|
21
|
Kornegay JN, Spurney CF, Nghiem PP, Brinkmeyer-Langford CL, Hoffman EP, Nagaraju K. Pharmacologic management of Duchenne muscular dystrophy: target identification and preclinical trials. ILAR J 2015; 55:119-49. [PMID: 24936034 DOI: 10.1093/ilar/ilu011] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked human disorder in which absence of the protein dystrophin causes degeneration of skeletal and cardiac muscle. For the sake of treatment development, over and above definitive genetic and cell-based therapies, there is considerable interest in drugs that target downstream disease mechanisms. Drug candidates have typically been chosen based on the nature of pathologic lesions and presumed underlying mechanisms and then tested in animal models. Mammalian dystrophinopathies have been characterized in mice (mdx mouse) and dogs (golden retriever muscular dystrophy [GRMD]). Despite promising results in the mdx mouse, some therapies have not shown efficacy in DMD. Although the GRMD model offers a higher hurdle for translation, dogs have primarily been used to test genetic and cellular therapies where there is greater risk. Failed translation of animal studies to DMD raises questions about the propriety of methods and models used to identify drug targets and test efficacy of pharmacologic intervention. The mdx mouse and GRMD dog are genetically homologous to DMD but not necessarily analogous. Subcellular species differences are undoubtedly magnified at the whole-body level in clinical trials. This problem is compounded by disparate cultures in clinical trials and preclinical studies, pointing to a need for greater rigor and transparency in animal experiments. Molecular assays such as mRNA arrays and genome-wide association studies allow identification of genetic drug targets more closely tied to disease pathogenesis. Genes in which polymorphisms have been directly linked to DMD disease progression, as with osteopontin, are particularly attractive targets.
Collapse
|
22
|
Kornegay JN, Peterson JM, Bogan DJ, Kline W, Bogan JR, Dow JL, Fan Z, Wang J, Ahn M, Zhu H, Styner M, Guttridge DC. NBD delivery improves the disease phenotype of the golden retriever model of Duchenne muscular dystrophy. Skelet Muscle 2014; 4:18. [PMID: 25789154 PMCID: PMC4364341 DOI: 10.1186/2044-5040-4-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/25/2014] [Indexed: 01/19/2023] Open
Abstract
Background Duchenne muscular dystrophy (DMD) is caused by mutations in the dystrophin gene and afflicts skeletal and cardiac muscles. Previous studies showed that DMD is associated with constitutive activation of NF-κB, and in dystrophin-deficient mdx and utrophin/dystrophin (utrn-/-;mdx) double knock out (dko) mouse models, inhibition of NF-κB with the Nemo Binding Domain (NBD) peptide led to significant improvements in both diaphragm and cardiac muscle function. Methods A trial in golden retriever muscular dystrophy (GRMD) canine model of DMD was initiated with four primary outcomes: skeletal muscle function, MRI of pelvic limb muscles, histopathologic features of skeletal muscles, and safety. GRMD and wild type dogs at 2 months of age were treated for 4 months with NBD by intravenous infusions. Results were compared with those collected from untreated GRMD and wild type dogs through a separate, natural history study. Results Results showed that intravenous delivery of NBD in GRMD dogs led to a recovery of pelvic limb muscle force and improvement of histopathologic lesions. In addition, NBD-treated GRMD dogs had normalized postural changes and a trend towards lower tissue injury on magnetic resonance imaging. Despite this phenotypic improvement, NBD administration over time led to infusion reactions and an immune response in both treated GRMD and wild type dogs. Conclusions This GRMD trial was beneficial both in providing evidence that NBD is efficacious in a large animal DMD model and in identifying potential safety concerns that will be informative moving forward with human trials.
Collapse
Affiliation(s)
- Joe N Kornegay
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA ; Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA ; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA ; Department of Veterinary Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, Mail Stop 4458, College Station, TX, USA
| | - Jennifer M Peterson
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel J Bogan
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA ; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - William Kline
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Janet R Bogan
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA ; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jennifer L Dow
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA ; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Zheng Fan
- Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jiahui Wang
- Department of Psychiatry, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Mihye Ahn
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Hongtu Zhu
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Martin Styner
- Department of Psychiatry, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA ; Department of Computer Science, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Denis C Guttridge
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA ; The Ohio State University College of Medicine, 460W. 12th Avenue, Columbus, OH 43210, USA
| |
Collapse
|
23
|
Sharma P, Basu S, Mitchell RW, Stelmack GL, Anderson JE, Halayko AJ. Role of dystrophin in airway smooth muscle phenotype, contraction and lung function. PLoS One 2014; 9:e102737. [PMID: 25054970 PMCID: PMC4108318 DOI: 10.1371/journal.pone.0102737] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 06/23/2014] [Indexed: 11/19/2022] Open
Abstract
Dystrophin links the transmembrane dystrophin-glycoprotein complex to the actin cytoskeleton. We have shown that dystrophin-glycoprotein complex subunits are markers for airway smooth muscle phenotype maturation and together with caveolin-1, play an important role in calcium homeostasis. We tested if dystrophin affects phenotype maturation, tracheal contraction and lung physiology. We used dystrophin deficient Golden Retriever dogs (GRMD) and mdx mice vs healthy control animals in our approach. We found significant reduction of contractile protein markers: smooth muscle myosin heavy chain (smMHC) and calponin and reduced Ca2+ response to contractile agonist in dystrophin deficient cells. Immunocytochemistry revealed reduced stress fibers and number of smMHC positive cells in dystrophin-deficient cells, when compared to control. Immunoblot analysis of Akt1, GSK3β and mTOR phosphorylation further revealed that downstream PI3K signaling, which is essential for phenotype maturation, was suppressed in dystrophin deficient cell cultures. Tracheal rings from mdx mice showed significant reduction in the isometric contraction to methacholine (MCh) when compared to genetic control BL10ScSnJ mice (wild-type). In vivo lung function studies using a small animal ventilator revealed a significant reduction in peak airway resistance induced by maximum concentrations of inhaled MCh in mdx mice, while there was no change in other lung function parameters. These data show that the lack of dystrophin is associated with a concomitant suppression of ASM cell phenotype maturation in vitro, ASM contraction ex vivo and lung function in vivo, indicating that a linkage between the DGC and the actin cytoskeleton via dystrophin is a determinant of the phenotype and functional properties of ASM.
Collapse
MESH Headings
- Animals
- Blotting, Western
- Cells, Cultured
- Dogs
- Dystrophin/deficiency
- Dystrophin/genetics
- Dystrophin/physiology
- Immunohistochemistry
- Lung/metabolism
- Lung/physiology
- Methacholine Chloride/pharmacology
- Mice, Inbred mdx
- Mice, Knockout
- Microscopy, Electron, Transmission
- Microscopy, Fluorescence
- Muscle Contraction/genetics
- Muscle Contraction/physiology
- Muscle, Smooth/cytology
- Muscle, Smooth/metabolism
- Muscle, Smooth/physiology
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/physiology
- Myosin Heavy Chains/metabolism
- Phosphatidylinositol 3-Kinases/metabolism
- Respiratory System/cytology
- Respiratory System/metabolism
- Respiratory System/ultrastructure
- Signal Transduction/genetics
- Signal Transduction/physiology
- Trachea/drug effects
- Trachea/metabolism
- Trachea/physiology
Collapse
Affiliation(s)
- Pawan Sharma
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada
- CIHR National Training Program in Allergy and Asthma, University of Manitoba, Winnipeg, Manitoba, Canada
- Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada
| | - Sujata Basu
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada
- Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada
| | - Richard W. Mitchell
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada
- Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada
| | - Gerald L. Stelmack
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada
- Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada
| | - Judy E. Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Andrew J. Halayko
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Internal Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
- Section of Respiratory Disease, University of Manitoba, Winnipeg, Manitoba, Canada
- CIHR National Training Program in Allergy and Asthma, University of Manitoba, Winnipeg, Manitoba, Canada
- Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada
- * E-mail:
| |
Collapse
|
24
|
Nghiem PP, Hoffman EP, Mittal P, Brown KJ, Schatzberg SJ, Ghimbovschi S, Wang Z, Kornegay JN. Sparing of the dystrophin-deficient cranial sartorius muscle is associated with classical and novel hypertrophy pathways in GRMD dogs. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 183:1411-24. [PMID: 24160322 DOI: 10.1016/j.ajpath.2013.07.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 12/28/2022]
Abstract
Both Duchenne and golden retriever muscular dystrophy (GRMD) are caused by dystrophin deficiency. The Duchenne muscular dystrophy sartorius muscle and orthologous GRMD cranial sartorius (CS) are relatively spared/hypertrophied. We completed hierarchical clustering studies to define molecular mechanisms contributing to this differential involvement and their role in the GRMD phenotype. GRMD dogs with larger CS muscles had more severe deficits, suggesting that selective hypertrophy could be detrimental. Serial biopsies from the hypertrophied CS and other atrophied muscles were studied in a subset of these dogs. Myostatin showed an age-dependent decrease and an inverse correlation with the degree of GRMD CS hypertrophy. Regulators of myostatin at the protein (AKT1) and miRNA (miR-539 and miR-208b targeting myostatin mRNA) levels were altered in GRMD CS, consistent with down-regulation of myostatin signaling, CS hypertrophy, and functional rescue of this muscle. mRNA and proteomic profiling was used to identify additional candidate genes associated with CS hypertrophy. The top-ranked network included α-dystroglycan and like-acetylglucosaminyltransferase. Proteomics demonstrated increases in myotrophin and spectrin that could promote hypertrophy and cytoskeletal stability, respectively. Our results suggest that multiple pathways, including decreased myostatin and up-regulated miRNAs, α-dystroglycan/like-acetylglucosaminyltransferase, spectrin, and myotrophin, contribute to hypertrophy and functional sparing of the CS. These data also underscore the muscle-specific responses to dystrophin deficiency and the potential deleterious effects of differential muscle involvement.
Collapse
Affiliation(s)
- Peter P Nghiem
- Department of Integrative Systems Biology, George Washington University School of Medicine, Washington, District of Columbia; Research Center for Genetic Medicine, Children's National Medical Center, Washington, District of Columbia
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Hagedorn TM, Jensen JA, Komáromy AM. A golden retriever with bilateral blepharospasm and ocular discharge. Lab Anim (NY) 2014; 43:127-30. [PMID: 24651787 DOI: 10.1038/laban.329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Travis M Hagedorn
- 1] University of Pennsylvania, University Laboratory Animal Resources, Philadelphia, PA. [2] University of Kansas Medical Center, Laboratory Animal Resources, Kansas City, KS
| | - JanLee A Jensen
- University of Pennsylvania, University Laboratory Animal Resources, Philadelphia, PA
| | - András M Komáromy
- 1] University of Pennsylvania, School of Veterinary Medicine, Department of Clinical Studies, Philadelphia, PA. [2] Michigan State University, College of Veterinary Medicine, Department of Small Animal Clinical Sciences, East Lansing, MI
| |
Collapse
|
26
|
Brinkmeyer-Langford C, Kornegay JN. Comparative Genomics of X-linked Muscular Dystrophies: The Golden Retriever Model. Curr Genomics 2014; 14:330-42. [PMID: 24403852 PMCID: PMC3763684 DOI: 10.2174/13892029113149990004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/16/2013] [Accepted: 07/19/2013] [Indexed: 12/30/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a devastating disease that dramatically decreases the lifespan and abilities of affected young people. The primary molecular cause of the disease is the absence of functional dystrophin protein, which is critical to proper muscle function. Those with DMD vary in disease presentation and dystrophin mutation; the same causal mutation may be associated with drastically different levels of disease severity. Also contributing to this variation are the influences of additional modifying genes and/or changes in functional elements governing such modifiers. This genetic heterogeneity complicates the efficacy of treatment methods and to date medical interventions are limited to treating symptoms. Animal models of DMD have been instrumental in teasing out the intricacies of DMD disease and hold great promise for advancing knowledge of its variable presentation and treatment. This review addresses the utility of comparative genomics in elucidating the complex background behind phenotypic variation in a canine model of DMD, Golden Retriever muscular dystrophy (GRMD). This knowledge can be exploited in the development of improved, more personalized treatments for DMD patients, such as therapies that can be tailor-matched to the disease course and genomic background of individual patients.
Collapse
Affiliation(s)
- Candice Brinkmeyer-Langford
- Texas A&M University College of Veterinary Medicine, Dept. of Veterinary Integrative Biosciences - Mailstop 4458, College Station, Texas, U.S.A. 77843-4458
| | - Joe N Kornegay
- Texas A&M University College of Veterinary Medicine, Dept. of Veterinary Integrative Biosciences - Mailstop 4458, College Station, Texas, U.S.A. 77843-4458
| |
Collapse
|
27
|
Mead AF, Petrov M, Malik AS, Mitchell MA, Childers MK, Bogan JR, Seidner G, Kornegay JN, Stedman HH. Diaphragm remodeling and compensatory respiratory mechanics in a canine model of Duchenne muscular dystrophy. J Appl Physiol (1985) 2014; 116:807-15. [PMID: 24408990 DOI: 10.1152/japplphysiol.00833.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ventilatory insufficiency remains the leading cause of death and late stage morbidity in Duchenne muscular dystrophy (DMD). To address critical gaps in our knowledge of the pathobiology of respiratory functional decline, we used an integrative approach to study respiratory mechanics in a translational model of DMD. In studies of individual dogs with the Golden Retriever muscular dystrophy (GRMD) mutation, we found evidence of rapidly progressive loss of ventilatory capacity in association with dramatic morphometric remodeling of the diaphragm. Within the first year of life, the mechanics of breathing at rest, and especially during pharmacological stimulation of respiratory control pathways in the carotid bodies, shift such that the primary role of the diaphragm becomes the passive elastic storage of energy transferred from abdominal wall muscles, thereby permitting the expiratory musculature to share in the generation of inspiratory pressure and flow. In the diaphragm, this physiological shift is associated with the loss of sarcomeres in series (∼ 60%) and an increase in muscle stiffness (∼ 900%) compared with those of the nondystrophic diaphragm, as studied during perfusion ex vivo. In addition to providing much needed endpoint measures for assessing the efficacy of therapeutics, we expect these findings to be a starting point for a more precise understanding of respiratory failure in DMD.
Collapse
Affiliation(s)
- A F Mead
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
DeVanna JC, Kornegay JN, Bogan DJ, Bogan JR, Dow JL, Hawkins EC. Respiratory dysfunction in unsedated dogs with golden retriever muscular dystrophy. Neuromuscul Disord 2013; 24:63-73. [PMID: 24295812 DOI: 10.1016/j.nmd.2013.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 10/14/2013] [Accepted: 10/16/2013] [Indexed: 12/30/2022]
Abstract
Golden retriever muscular dystrophy (GRMD) is a well-established model of Duchenne muscular dystrophy. The value of this model would be greatly enhanced with practical tools to monitor progression of respiratory dysfunction during treatment trials. Arterial blood gas analysis, tidal breathing spirometry, and respiratory inductance plethysmography (RIP) were performed to determine if quantifiable abnormalities could be identified in unsedated, untrained, GRMD dogs. Results from 11 dogs with a mild phenotype of GRMD and 11 age-matched carriers were compared. Arterial blood gas analysis was successfully performed in all dogs, spirometry in 21 of 22 (95%) dogs, and RIP in 18 of 20 (90%) dogs. Partial pressure of carbon dioxide and bicarbonate concentration were higher in GRMD dogs. Tidal breathing peak expiratory flows were markedly higher in GRMD dogs. Abnormal abdominal motion was present in 7 of 10 (70%) GRMD dogs. Each technique provided objective, quantifiable measures that will be useful for monitoring respiratory function in GRMD dogs during clinical trials while avoiding the influence of sedation on results. Increased expiratory flows and the pattern of abdominal breathing are novel findings, not reported in people with Duchenne muscular dystrophy, and might be a consequence of hyperinflation.
Collapse
Affiliation(s)
- Justin C DeVanna
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, United States
| | - Joe N Kornegay
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Daniel J Bogan
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Janet R Bogan
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Jennifer L Dow
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Eleanor C Hawkins
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, United States.
| |
Collapse
|
29
|
Partridge TA. The mdx mouse model as a surrogate for Duchenne muscular dystrophy. FEBS J 2013; 280:4177-86. [PMID: 23551987 DOI: 10.1111/febs.12267] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/18/2013] [Accepted: 03/19/2013] [Indexed: 01/06/2023]
Abstract
Research into fundamental principles and the testing of therapeutic hypotheses for treatment of human disease is commonly performed on mouse models of human diseases. Although this is often the only practicable approach, it carries a number of caveats arising from differences between the two species. This review focuses on the example of skeletal muscle disease, in particular muscular dystrophy, to identify some of the principal classes of obstacles to translation of data from mouse to humans. Of these, the difference in scale is one of the most commonly ignored, and is of particular interest because it has quite major repercussions for evaluation of some classes of intervention and of outcome criteria, while having comparatively little bearing on others. Likewise, inter-species differences and similarities in cell and molecular biological mechanisms underlying development, growth and response to pathological processes should be considered on an individual basis. An awareness of such distinctions is crucial if we are to avoid misjudging the likely applicability to humans of results obtained on mouse models.
Collapse
Affiliation(s)
- Terence A Partridge
- Children's National Medical Center, Center for Genetic Medicine, Washington, DC 20010, USA.
| |
Collapse
|
30
|
Kornegay JN, Childers MK, Bogan DJ, Bogan JR, Nghiem P, Wang J, Fan Z, Howard JF, Schatzberg SJ, Dow JL, Grange RW, Styner MA, Hoffman EP, Wagner KR. The paradox of muscle hypertrophy in muscular dystrophy. Phys Med Rehabil Clin N Am 2012; 23:149-72, xii. [PMID: 22239881 DOI: 10.1016/j.pmr.2011.11.014] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mutations in the dystrophin gene cause Duchenne and Becker muscular dystrophy in humans and syndromes in mice, dogs, and cats. Affected humans and dogs have progressive disease that leads primarily to muscle atrophy. Mdx mice progress through an initial phase of muscle hypertrophy followed by atrophy. Cats have persistent muscle hypertrophy. Hypertrophy in humans has been attributed to deposition of fat and connective tissue (pseudohypertrophy). Increased muscle mass (true hypertrophy) has been documented in animal models. Muscle hypertrophy can exaggerate postural instability and joint contractures. Deleterious consequences of muscle hypertrophy should be considered when developing treatments for muscular dystrophy.
Collapse
Affiliation(s)
- Joe N Kornegay
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Childers MK, Bogan JR, Bogan DJ, Greiner H, Holder M, Grange RW, Kornegay JN. Chronic administration of a leupeptin-derived calpain inhibitor fails to ameliorate severe muscle pathology in a canine model of duchenne muscular dystrophy. Front Pharmacol 2012; 2:89. [PMID: 22291646 PMCID: PMC3253583 DOI: 10.3389/fphar.2011.00089] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2011] [Accepted: 12/18/2011] [Indexed: 11/18/2022] Open
Abstract
Calpains likely play a role in the pathogenesis of Duchenne muscular dystrophy (DMD). Accordingly, calpain inhibition may provide therapeutic benefit to DMD patients. In the present study, we sought to measure benefit from administration of a novel calpain inhibitor, C101, in a canine muscular dystrophy model. Specifically, we tested the hypothesis that treatment with C101 mitigates progressive weakness and severe muscle pathology observed in young dogs with golden retriever muscular dystrophy (GRMD). Young (6-week-old) GRMD dogs were treated daily with either C101 (17 mg/kg twice daily oral dose, n = 9) or placebo (vehicle only, n = 7) for 8 weeks. A battery of functional tests, including tibiotarsal joint angle, muscle/fat composition, and pelvic limb muscle strength were performed at baseline and every 2 weeks during the 8-week study. Results indicate that C101-treated GRMD dogs maintained strength in their cranial pelvic limb muscles (tibiotarsal flexors) while placebo-treated dogs progressively lost strength. However, concomitant improvement was not observed in posterior pelvic limb muscles (tibiotarsal extensors). C101 treatment did not mitigate force drop following repeated eccentric contractions and no improvement was seen in the development of joint contractures, lean muscle mass, or muscle histopathology. Taken together, these data do not support the hypothesis that treatment with C101 mitigates progressive weakness or ameliorates severe muscle pathology observed in young dogs with GRMD.
Collapse
Affiliation(s)
- Martin K Childers
- Department of Neurology, Wake Forest University Health Sciences Winston-Salem, NC, USA.
| | | | | | | | | | | | | |
Collapse
|
32
|
Kornegay JN, Bogan JR, Bogan DJ, Childers MK, Li J, Nghiem P, Detwiler DA, Larsen CA, Grange RW, Bhavaraju-Sanka RK, Tou S, Keene BP, Howard JF, Wang J, Fan Z, Schatzberg SJ, Styner MA, Flanigan KM, Xiao X, Hoffman EP. Canine models of Duchenne muscular dystrophy and their use in therapeutic strategies. Mamm Genome 2012; 23:85-108. [PMID: 22218699 DOI: 10.1007/s00335-011-9382-y] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 11/29/2011] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder in which the loss of dystrophin causes progressive degeneration of skeletal and cardiac muscle. Potential therapies that carry substantial risk, such as gene- and cell-based approaches, must first be tested in animal models, notably the mdx mouse and several dystrophin-deficient breeds of dogs, including golden retriever muscular dystrophy (GRMD). Affected dogs have a more severe phenotype, in keeping with that of DMD, so may better predict disease pathogenesis and treatment efficacy. Various phenotypic tests have been developed to characterize disease progression in the GRMD model. These biomarkers range from measures of strength and joint contractures to magnetic resonance imaging. Some of these tests are routinely used in clinical veterinary practice, while others require specialized equipment and expertise. By comparing serial measurements from treated and untreated groups, one can document improvement or delayed progression of disease. Potential treatments for DMD may be broadly categorized as molecular, cellular, or pharmacologic. The GRMD model has increasingly been used to assess efficacy of a range of these therapies. A number of these studies have provided largely general proof-of-concept for the treatment under study. Others have demonstrated efficacy using the biomarkers discussed. Importantly, just as symptoms in DMD vary among patients, GRMD dogs display remarkable phenotypic variation. Though confounding statistical analysis in preclinical trials, this variation offers insight regarding the role that modifier genes play in disease pathogenesis. By correlating functional and mRNA profiling results, gene targets for therapy development can be identified.
Collapse
Affiliation(s)
- Joe N Kornegay
- Department of Pathology and Laboratory Medicine, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Establishing clinical end points of respiratory function in large animals for clinical translation. Phys Med Rehabil Clin N Am 2011; 23:75-94, xi. [PMID: 22239876 DOI: 10.1016/j.pmr.2011.11.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Respiratory dysfunction due progressive weakness of the respiratory muscles, particularly the diaphragm, is a major cause of death in the neuromuscular disease (NMD) X-linked myotubular myopathy (XLMTM). Methods of respiratory assessment in patients are often difficult, especially in those who are mechanically ventilated. The naturally occuring XLMTM dog model exhibits a phenotype similar to that in patients and can be used to determine quantitative descriptions of dysfunction as clinical endpoints for treatment and the development of new therapies. In experiments using respiratory impedance plethysmography (RIP), XLMTM dogs challenged with the respiratory stimulant doxapram displayed significant changes indicative of diaphragmatic weakness.
Collapse
|