1
|
Rovira Gonzalez YI, Moyer AL, LeTexier NJ, Bratti AD, Feng S, Peña V, Sun C, Pulcastro H, Liu T, Iyer SR, Lovering RM, O'Rourke B, Wagner KR. Mss51 deletion increases endurance and ameliorates histopathology in the mdx mouse model of Duchenne muscular dystrophy. FASEB J 2021; 35:e21276. [PMID: 33423297 DOI: 10.1096/fj.202002106rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 11/11/2022]
Abstract
Mitochondrial derangement is an important contributor to the pathophysiology of muscular dystrophies and may be among the earliest cellular deficits. We have previously shown that disruption of Mss51, a mammalian skeletal muscle protein that localizes to the mitochondria, results in enhanced muscle oxygen consumption rate, increased endurance capacity, and improved limb muscle strength in mice with wildtype background. Here, we investigate whether Mss51 deletion in the mdx murine model of Duchenne muscular dystrophy (mdx-Mss51 KO) counteracts the muscle pathology and mitochondrial irregularities observed in mdx mice. We found that mdx-Mss51 KO mice had increased myofiber oxygen consumption rates and an amelioration of muscle histopathology compared to mdx counterparts. This corresponded with greater treadmill endurance and less percent fatigue in muscle physiology, but no improvement in forelimb grip strength or limb muscle force production. These findings suggest that although Mss51 deletion ameliorates the skeletal muscle mitochondrial respiration defects in mdx and improves fatigue resistance in vivo, the lack of improvement in force production suggests that this target alone may be insufficient for a therapeutic effect.
Collapse
Affiliation(s)
- Yazmin I Rovira Gonzalez
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA.,Cellular and Molecular Medicine Graduate Program, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Adam L Moyer
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA.,Cellular and Molecular Medicine Graduate Program, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Nicolas J LeTexier
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA
| | - August D Bratti
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Siyuan Feng
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Vanessa Peña
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Congshan Sun
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA.,Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Hannah Pulcastro
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Ting Liu
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shama R Iyer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Brian O'Rourke
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kathryn R Wagner
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA.,Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA
| |
Collapse
|
2
|
Timpani CA, Goodman CA, Stathis CG, White JD, Mamchaoui K, Butler-Browne G, Gueven N, Hayes A, Rybalka E. Adenylosuccinic acid therapy ameliorates murine Duchenne Muscular Dystrophy. Sci Rep 2020; 10:1125. [PMID: 31980663 PMCID: PMC6981178 DOI: 10.1038/s41598-020-57610-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 12/30/2019] [Indexed: 12/13/2022] Open
Abstract
Arising from the ablation of the cytoskeletal protein dystrophin, Duchenne Muscular Dystrophy (DMD) is a debilitating and fatal skeletal muscle wasting disease underpinned by metabolic insufficiency. The inability to facilitate adequate energy production may impede calcium (Ca2+) buffering within, and the regenerative capacity of, dystrophic muscle. Therefore, increasing the metabogenic potential could represent an effective treatment avenue. The aim of our study was to determine the efficacy of adenylosuccinic acid (ASA), a purine nucleotide cycle metabolite, to stimulate metabolism and buffer skeletal muscle damage in the mdx mouse model of DMD. Dystrophin-positive control (C57BL/10) and dystrophin-deficient mdx mice were treated with ASA (3000 µg.mL−1) in drinking water. Following the 8-week treatment period, metabolism, mitochondrial density, viability and superoxide (O2−) production, as well as skeletal muscle histopathology, were assessed. ASA treatment significantly improved the histopathological features of murine DMD by reducing damage area, the number of centronucleated fibres, lipid accumulation, connective tissue infiltration and Ca2+ content of mdx tibialis anterior. These effects were independent of upregulated utrophin expression in the tibialis anterior. ASA treatment also increased mitochondrial viability in mdx flexor digitorum brevis fibres and concomitantly reduced O2− production, an effect that was also observed in cultured immortalised human DMD myoblasts. Our data indicates that ASA has a protective effect on mdx skeletal muscles.
Collapse
Affiliation(s)
- Cara A Timpani
- Institute for Health and Sport, Victoria University, Melbourne, Victoria, 8001, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), Victoria University, St Albans, Victoria, 3021, Australia
| | - Craig A Goodman
- Institute for Health and Sport, Victoria University, Melbourne, Victoria, 8001, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), Victoria University, St Albans, Victoria, 3021, Australia
| | - Christos G Stathis
- Institute for Health and Sport, Victoria University, Melbourne, Victoria, 8001, Australia
| | - Jason D White
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.,Melbourne Veterinary School, University of Melbourne, Parkville, Victoria, Australia
| | - Kamel Mamchaoui
- Institut de Myologie, Sorbonne University, INSERM UMRS974, Paris, France
| | | | - Nuri Gueven
- Pharmacy, School of Medicine, University of Tasmania, Hobart, Tasmania, 7000, Australia
| | - Alan Hayes
- Institute for Health and Sport, Victoria University, Melbourne, Victoria, 8001, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), Victoria University, St Albans, Victoria, 3021, Australia.,Department of Medicine-Western Health, The University of Melbourne, St Albans, Victoria, 3021, Australia
| | - Emma Rybalka
- Institute for Health and Sport, Victoria University, Melbourne, Victoria, 8001, Australia. .,Australian Institute for Musculoskeletal Science (AIMSS), Victoria University, St Albans, Victoria, 3021, Australia.
| |
Collapse
|
3
|
Lagu B, Kluge AF, Tozzo E, Fredenburg R, Bell EL, Goddeeris MM, Dwyer P, Basinski A, Senaiar RS, Jaleel M, Tiwari NK, Panigrahi SK, Krishnamurthy NR, Takahashi T, Patane MA. Selective PPARδ Modulators Improve Mitochondrial Function: Potential Treatment for Duchenne Muscular Dystrophy (DMD). ACS Med Chem Lett 2018; 9:935-940. [PMID: 30258544 DOI: 10.1021/acsmedchemlett.8b00287] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 07/31/2018] [Indexed: 01/14/2023] Open
Abstract
The X-ray structure of the previously reported PPARδ modulator 1 bound to the ligand binding domain (LBD) revealed that the amide moiety in 1 exists in the thermodynamically disfavored cis-amide orientation. Isosteric replacement of the cis-amide with five-membered heterocycles led to the identification of imidazole 17 (MA-0204), a potent, selective PPARδ modulator with good pharmacokinetic properties. MA-0204 was tested in vivo in mice and in vitro in patient-derived muscle myoblasts (from Duchenne Muscular Dystrophy (DMD) patients); 17 altered the expression of PPARδ target genes and improved fatty acid oxidation, which supports the therapeutic hypothesis for the study of MA-0204 in DMD patients.
Collapse
Affiliation(s)
- Bharat Lagu
- Mitobridge, Inc. (a wholly owned subsidiary of Astellas Pharma.), 1030 Massachusetts Avenue, Cambridge, Massachusetts 02138, United States
| | - Arthur F. Kluge
- Mitobridge, Inc. (a wholly owned subsidiary of Astellas Pharma.), 1030 Massachusetts Avenue, Cambridge, Massachusetts 02138, United States
| | - Effie Tozzo
- Mitobridge, Inc. (a wholly owned subsidiary of Astellas Pharma.), 1030 Massachusetts Avenue, Cambridge, Massachusetts 02138, United States
| | - Ross Fredenburg
- Mitobridge, Inc. (a wholly owned subsidiary of Astellas Pharma.), 1030 Massachusetts Avenue, Cambridge, Massachusetts 02138, United States
| | - Eric L. Bell
- Mitobridge, Inc. (a wholly owned subsidiary of Astellas Pharma.), 1030 Massachusetts Avenue, Cambridge, Massachusetts 02138, United States
| | - Matthew M. Goddeeris
- Mitobridge, Inc. (a wholly owned subsidiary of Astellas Pharma.), 1030 Massachusetts Avenue, Cambridge, Massachusetts 02138, United States
| | - Peter Dwyer
- Mitobridge, Inc. (a wholly owned subsidiary of Astellas Pharma.), 1030 Massachusetts Avenue, Cambridge, Massachusetts 02138, United States
| | - Andrew Basinski
- Mitobridge, Inc. (a wholly owned subsidiary of Astellas Pharma.), 1030 Massachusetts Avenue, Cambridge, Massachusetts 02138, United States
| | - Ramesh S. Senaiar
- Aurigene Discovery Technologies, Ltd., Bengaluru and Hyderabad, India
| | - Mahaboobi Jaleel
- Aurigene Discovery Technologies, Ltd., Bengaluru and Hyderabad, India
| | | | | | | | | | - Michael A. Patane
- Mitobridge, Inc. (a wholly owned subsidiary of Astellas Pharma.), 1030 Massachusetts Avenue, Cambridge, Massachusetts 02138, United States
| |
Collapse
|
4
|
Bell EL, Shine RW, Dwyer P, Olson L, Truong J, Fredenburg R, Goddeeris M, Stickens D, Tozzo E. PPARδ modulation rescues mitochondrial fatty acid oxidation defects in the mdx model of muscular dystrophy. Mitochondrion 2018; 46:51-58. [PMID: 29458111 DOI: 10.1016/j.mito.2018.02.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 02/05/2018] [Accepted: 02/15/2018] [Indexed: 12/25/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a recessive, fatal X-linked disease that is characterized by progressive skeletal muscle wasting due to the absence of dystrophin, which is an a essential protein that bridges the inner cytoskeleton and extra-cellular matrix. This study set out to characterize the mitochondria in primary muscle satellite cell derived myoblasts from mdx mice and wild type control mice. Compared to wild type derived cells the mdx derived cells have reduced mitochondrial bioenergetics and have fewer mitochondria. Here, we demonstrate that a novel PPARδ modulator improves mitochondrial function in the mdx mice, which supports that modulating PPARδ may be therapeutically beneficial in DMD patients.
Collapse
Affiliation(s)
- Eric L Bell
- Mitobridge, Inc, 1030 Massachusetts Avenue, Cambridge, MA 02138, United States.
| | - Robert W Shine
- Mitobridge, Inc, 1030 Massachusetts Avenue, Cambridge, MA 02138, United States
| | - Peter Dwyer
- Mitobridge, Inc, 1030 Massachusetts Avenue, Cambridge, MA 02138, United States
| | - Lyndsay Olson
- Mitobridge, Inc, 1030 Massachusetts Avenue, Cambridge, MA 02138, United States
| | - Jennifer Truong
- Mitobridge, Inc, 1030 Massachusetts Avenue, Cambridge, MA 02138, United States
| | - Ross Fredenburg
- Mitobridge, Inc, 1030 Massachusetts Avenue, Cambridge, MA 02138, United States
| | - Matthew Goddeeris
- Mitobridge, Inc, 1030 Massachusetts Avenue, Cambridge, MA 02138, United States
| | - Dominique Stickens
- Mitobridge, Inc, 1030 Massachusetts Avenue, Cambridge, MA 02138, United States
| | - Effie Tozzo
- Mitobridge, Inc, 1030 Massachusetts Avenue, Cambridge, MA 02138, United States
| |
Collapse
|
5
|
Rybalka E, Timpani CA, Stathis CG, Hayes A, Cooke MB. Metabogenic and Nutriceutical Approaches to Address Energy Dysregulation and Skeletal Muscle Wasting in Duchenne Muscular Dystrophy. Nutrients 2015; 7:9734-67. [PMID: 26703720 PMCID: PMC4690050 DOI: 10.3390/nu7125498] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/29/2015] [Accepted: 11/13/2015] [Indexed: 12/21/2022] Open
Abstract
Duchenne Muscular Dystrophy (DMD) is a fatal genetic muscle wasting disease with no current cure. A prominent, yet poorly treated feature of dystrophic muscle is the dysregulation of energy homeostasis which may be associated with intrinsic defects in key energy systems and promote muscle wasting. As such, supplementative nutriceuticals that target and augment the bioenergetical expansion of the metabolic pathways involved in cellular energy production have been widely investigated for their therapeutic efficacy in the treatment of DMD. We describe the metabolic nuances of dystrophin-deficient skeletal muscle and review the potential of various metabogenic and nutriceutical compounds to ameliorate the pathological and clinical progression of the disease.
Collapse
Affiliation(s)
- Emma Rybalka
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne 8001, Australia.
- Institute of Sport, Exercise & Healthy Living, Victoria University, Melbourne 8001, Australia.
- Australian Institute of Musculoskeletal Science, Western Health, Melbourne 3021, Australia.
| | - Cara A Timpani
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne 8001, Australia.
- Institute of Sport, Exercise & Healthy Living, Victoria University, Melbourne 8001, Australia.
| | - Christos G Stathis
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne 8001, Australia.
- Institute of Sport, Exercise & Healthy Living, Victoria University, Melbourne 8001, Australia.
- Australian Institute of Musculoskeletal Science, Western Health, Melbourne 3021, Australia.
| | - Alan Hayes
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne 8001, Australia.
- Institute of Sport, Exercise & Healthy Living, Victoria University, Melbourne 8001, Australia.
- Australian Institute of Musculoskeletal Science, Western Health, Melbourne 3021, Australia.
| | - Matthew B Cooke
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne 8001, Australia.
- Institute of Sport, Exercise & Healthy Living, Victoria University, Melbourne 8001, Australia.
- Australian Institute of Musculoskeletal Science, Western Health, Melbourne 3021, Australia.
| |
Collapse
|
6
|
Revisiting the dystrophin-ATP connection: How half a century of research still implicates mitochondrial dysfunction in Duchenne Muscular Dystrophy aetiology. Med Hypotheses 2015; 85:1021-33. [PMID: 26365249 DOI: 10.1016/j.mehy.2015.08.015] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/24/2015] [Indexed: 12/22/2022]
Abstract
Duchenne Muscular Dystrophy (DMD) is a fatal neuromuscular disease that is characterised by dystrophin-deficiency and chronic Ca(2+)-induced skeletal muscle wasting, which currently has no cure. DMD was once considered predominantly as a metabolic disease due to the myriad of metabolic insufficiencies evident in the musculature, however this aspect of the disease has been extensively ignored since the discovery of dystrophin. The collective historical and contemporary literature documenting these metabolic nuances has culminated in a series of studies that importantly demonstrate that metabolic dysfunction exists independent of dystrophin expression and a mild disease phenotype can be expressed even in the complete absence of dystrophin expression. Targeting and supporting metabolic pathways with anaplerotic and other energy-enhancing supplements has also shown therapeutic value. We explore the hypothesis that DMD is characterised by a systemic mitochondrial impairment that is central to disease aetiology rather than a secondary pathophysiological consequence of dystrophin-deficiency.
Collapse
|
7
|
Touboul D, Piednoël H, Voisin V, De La Porte S, Brunelle A, Halgand F, Laprévote O. Changes of phospholipid composition within the dystrophic muscle by matrix-assisted laser desorption/ionization mass spectrometry and mass spectrometry imaging. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2004; 10:657-664. [PMID: 15531799 DOI: 10.1255/ejms.671] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a neuromuscular disease linked to the lack of the dystrophin, a submembrane protein, leading to muscle weakness and associated with a defect of the lipid metabolism. A study of the fatty acid composition of glycerophosphatidylcholines by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS) and tandem mass spectrometry (MS/MS) enabled us to characterize a change of the lipid composition of dystrophic cells at the time of the differentiation. This modification has been used as a marker to identify with profiling and imaging MALDI-ToF MS regenerating areas in sections of an mdx mouse leg muscle. It is the first time that such a slight change in fatty acid composition has been observed directly on tissue slices using mass spectrometry. This approach will be useful in monitoring the treatment of muscular regeneration.
Collapse
Affiliation(s)
- David Touboul
- Laboratoire de Spectrométrie de Masse, Institut de Chimie des Substances Naturelles, CNRS, 1 Avenue de la Terrasse, F91198 Gif sur Yvette Cedex, France
| | | | | | | | | | | | | |
Collapse
|
8
|
Rae C, Griffin JL, Blair DH, Bothwell JH, Bubb WA, Maitland A, Head S. Abnormalities in brain biochemistry associated with lack of dystrophin: studies of the mdx mouse. Neuromuscul Disord 2002; 12:121-9. [PMID: 11738353 DOI: 10.1016/s0960-8966(01)00253-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Biochemical abnormalities have been reported in dystrophin-deficient muscle of boys with Duchenne (severe Xp21) muscular dystrophy or in the murine (mdx) model of the disease. These abnormalities include altered energy metabolism and responses to osmotic shock. In contrast, the situation in brain is less well understood and it is probable that dystrophin is playing a different role (or roles) in this organ. In this study we conclude that the elevation in choline-containing compounds reported in mdx brain is confined to cerebellum and hippocampus in older (> 6 months) mice. We report alterations in glucose metabolism in mdx brain under normal, awake conditions, and a reduced response of brain metabolism to the gamma-aminobutyric acid(A) receptor agonist muscimol. Using brain cortical slices we found no difference in the response of dystrophic tissue to hypoosmotic shock, but increased, substrate-dependent oxygen consumption rates at low oxygen partial pressures.
Collapse
Affiliation(s)
- Caroline Rae
- Department of Biochemistry, The University of Sydney, Sydney, NSW 2006, Australia.
| | | | | | | | | | | | | |
Collapse
|
9
|
Lodi R, Kemp GJ, Muntoni F, Thompson CH, Rae C, Taylor J, Styles P, Taylor DJ. Reduced cytosolic acidification during exercise suggests defective glycolytic activity in skeletal muscle of patients with Becker muscular dystrophy. An in vivo 31P magnetic resonance spectroscopy study. Brain 1999; 122 ( Pt 1):121-30. [PMID: 10050900 DOI: 10.1093/brain/122.1.121] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Becker muscular dystrophy is an X-linked disorder due to mutations in the dystrophin gene, resulting in reduced size and/or content of dystrophin. The functional role of this subsarcolemma protein and the biochemical mechanisms leading to muscle necrosis in Becker muscular dystrophy are still unknown. In particular, the role of a bioenergetic deficit is still controversial. In this study, we used 31p magnetic resonance spectroscopy (31p-MRS) to investigate skeletal muscle mitochondrial and glycolytic ATP production in vivo in 14 Becker muscular dystrophy patients. Skeletal muscle glycogenolytic ATP production, measured during the first minute of exercise, was similar in patients and controls. On the other hand, during later phases of exercise, skeletal muscle in Becker muscular dystrophy patients was less acidic than in controls, the cytosolic pH at the end of exercise being significantly higher in Becker muscular dystrophy patients. The rate of proton efflux from muscle fibres of Becker muscular dystrophy patients was similar to that of controls, pointing to a deficit in glycolytic lactate production as a cause of higher end-exercise cytosolic pH in patients. The maximum rate of mitochondrial ATP production was similar in muscle of Becker muscular dystrophy patients and controls. The results of this in vivo 31P-MRS study are consistent with reduced glucose availability in dystrophin-deficient muscles.
Collapse
Affiliation(s)
- R Lodi
- Oxford University Department of Biochemistry and Oxford Radcliffe Hospital, UK.
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Dunn JF, Tracey I, Radda GK. Exercise metabolism in Duchenne muscular dystrophy: a biochemical and [31P]-nuclear magnetic resonance study of mdx mice. Proc Biol Sci 1993; 251:201-6. [PMID: 8097327 DOI: 10.1098/rspb.1993.0030] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Intracellular pH, ratios of phosphocreatine (PCr) to ATP and PCr to inorganic phosphate (Pi) as well as isometric tension were measured during 1 Hz sciatic nerve stimulation and during recovery in the calf muscles of mdx (a model of Duchenne muscular dystrophy) and control mice. Tension did not decline significantly in either strain. The ratio of PCr/(PCr + Pi) was significantly reduced in mdx as against control muscle during exercise and recovery, but the ratio of PCr/ATP and the half-time for PCr recovery were similar in both strains. A reduction in the maximal activities of succinate dehydrogenase and succinate-cytochrome c reductase suggests that mitochondrial metabolism may be impaired. The similarity in PCr recovery times suggests that the muscle has adapted, making any impairment of oxidative metabolism negligible in the intact system. The rate of pH recovery is prolonged in mdx muscle and provides strong evidence for a decline in the capacity of dystrophic muscle to extrude proton equivalents. These data are compared with a previous study which used 10 Hz stimulation and also observed a slow pH recovery. The slow pH recovery could be explained by an elevation in intracellular sodium.
Collapse
Affiliation(s)
- J F Dunn
- Department of Biochemistry, University of Oxford, U.K
| | | | | |
Collapse
|
11
|
Abstract
Oxidative stress may be the fundamental basis of many of the structural, functional and biochemical changes characteristic of the inherited muscular dystrophies in animals and humans. The presence of by-products of oxidative damage, and the compensatory increases in cellular antioxidants, both indicate oxidative stress may be occurring in dystrophic muscle. Changes in the proportions and metabolism of cellular lipids, abnormal functions of cellular membranes, altered activity of membrane-bound enzymes such as the SR Ca2+-ATPase, disturbances in cellular protein turnover and energy production and a variety of other changes all indicate that these inherited muscular dystrophies appear more like the results of oxidative stress to muscle than any other type of underlying muscle disturbance. Particular details of these altered characteristics of dystrophic muscle, in combination with current knowledge on the processes of oxidative damage to cells, may provide some insight into the underlying biochemical defect responsible for the disease, as well as direct research towards the ultimate goal of an effective treatment.
Collapse
Affiliation(s)
- M E Murphy
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas, Austin 78712-1074
| | | |
Collapse
|
12
|
Yamamoto S, Matsushima H, Suzuki A, Sotobata I, Indo T, Matsuoka Y. A comparative study of thallium-201 single-photon emission computed tomography and electrocardiography in Duchenne and other types of muscular dystrophy. Am J Cardiol 1988; 61:836-43. [PMID: 3258468 DOI: 10.1016/0002-9149(88)91076-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Single-photon emission computed tomography (SPECT) using thallium-201 was compared with 12-lead electrocardiography (ECG) in patients with Duchenne (29), facioscapulohumeral (7), limb-girdle (6) and myotonic (5) dystrophies, by dividing the left ventricular (LV) wall into 5 segments. SPECT showed thallium defects (37 patients, mostly in the posteroapical wall), malrotation (23), apical aneurysm (5) and dilatation (7). ECG showed abnormal QRS (36 patients), particularly as a posterolateral pattern (13). Both methods of assessment were normal in only 7 patients. The Duchenne type frequently showed both a thallium defect (particularly in the posteroapical wall) and an abnormal QRS (predominantly in the posterolateral wall); the 3 other types showed abnormalities over the 5 LV wall segments in both tests. The percent of agreement between the 2 tests was 64, 66, 70, 72 and 72 for the lateral, apical, anteroseptal, posterior and inferior walls, respectively. The 2 tests were discordant in 31% of the LV wall, with SPECT (+) but ECG (-) in 21% (mostly in the apicoinferior wall) and SPECT (-) but ECG (+) in 10% (mostly in the lateral wall). Some patients showed large SPECT hypoperfusion despite minimal electrocardiographic changes. ECG thus appeared to underestimate LV fibrosis and to reflect posteroapical rather than posterolateral dystrophy in its posterolateral QRS pattern. In this disease, extensive SPECT hypoperfusion was also shown, irrespective of clinical subtype and skeletal involvement.
Collapse
Affiliation(s)
- S Yamamoto
- First Department of Internal Medicine, Nagoya University School of Medicine, Japan
| | | | | | | | | | | |
Collapse
|
13
|
Worton RG, Burghes AH. Molecular genetics of Duchenne and Becker muscular dystrophy. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1988; 29:1-76. [PMID: 3042661 DOI: 10.1016/s0074-7742(08)60083-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- R G Worton
- Genetics Department, Hospital for Sick Children, Toronto, Ontario, Canada
| | | |
Collapse
|
14
|
Abstract
An electrophoretic and enzyme-substrate staining technique for acyl-CoA dehydrogenase (ACD) enzymes was developed for use with small (less than 100 mg) tissue samples. Based on their electrophoretic mobility and substrate staining specificity, at least two and perhaps three chain-length specific enzymes for dehydrogenation of saturated fatty acids were found in human skeletal muscle. ACD enzymes staining with octanoyl-CoA or palmitoyl-CoA were identified by this technique in human skeletal muscle, heart, and liver, but the ACD enzyme staining with butyryl-CoA was difficult to detect and was definitely visualized only in skeletal muscle.
Collapse
|
15
|
Infante JP. Impaired biosynthesis of highly unsaturated phosphatidylcholines: a hypothesis on the molecular etiology of some muscular dystrophies. J Theor Biol 1985; 116:65-88. [PMID: 4046616 DOI: 10.1016/s0022-5193(85)80131-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A brief review of the literature concerning the synthesis of phosphatidylcholine and phosphatidylethanolamine in muscle suggests that the cytidine pathways are replaced by the recently proposed acyl-specific de novo and salvage glycerolphosphodiester pathways (Infante, 1984) in fully differentiated muscle. An analysis of published data suggests an impaired synthesis of 4,7,10,13,16,19-docosahexaenoic phosphatidylcholine, at the level of de novo sn-3-glycerolphosphorylcholine synthesis, as the primary defect in Duchenne and (dy) murine muscular dystrophies. This phosphatidylcholine species is postulated to be required for optimum sarcoplasmic Ca2+ transport activity. It is proposed that this impairment initiates the secondary series of events which lead to the observed pathology of these diseases. Based on some predictions of the hypothesis, potential diagnosis and treatments are suggested.
Collapse
|