Myofiber / pro-inflammatory macrophage interplay controls muscle damage in mdx mice

2020 ◽  
Author(s):  
Marielle Saclier ◽  
Sabrina Ben Larbi ◽  
Eugénie Moulin ◽  
Rémi Mounier ◽  
Bénédicte Chazaud ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Disease ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Dystrophic Muscle ◽  
Cellular Events ◽  
Inflammatory Status ◽  
Inflammatory Phenotype ◽  
Inflammatory Macrophages

SummaryDuchenne Muscular Dystrophy is a genetic muscle disease characterized by chronic inflammation and fibrosis, which is mediated by a pro-fibrotic macrophage population expressing pro-inflammatory markers. The aim of this study was to characterize cellular events leading to the alteration of macrophage properties, and to modulate macrophage inflammatory status using the gaseous mediator H2S. We first analyzed the relationship between myofibers and macrophages in the mdx mouse model of Duchenne Muscular Dystrophy using coculture experiments. We showed that normal myofibers derived from mdx mice strongly skewed the polarization of resting macrophages towards a pro-inflammatory phenotype. Treatment of mdx mice with NaHS, an H2S donor, reduced the number of pro-inflammatory macrophages in skeletal muscle, which was associated with a decrease in the number of nuclei per fiber, a reduction of myofiber branching and a reduced fibrosis. These results identify an interplay between myofibers and macrophages where dystrophic myofibers contribute to the maintenance of a highly inflammatory environment that skews the macrophage status, which in turn favors myofiber damage, myofiber branching and fibrosis establishment. They also identify H2S donors as a potential therapeutic strategy to improve dystrophic muscle phenotype by modulating macrophage inflammatory status.

scholarly journals Interplay between myofibers and pro-inflammatory macrophages controls muscle damage in mdx mice

2021 ◽  
Vol 134 (18) ◽  
Author(s):  
Marielle Saclier ◽  
Sabrina Ben Larbi ◽  
Ha My Ly ◽  
Eugénie Moulin ◽  
Rémi Mounier ◽  
...  
Keyword(s):  
Chronic Inflammation ◽  
Muscle Disease ◽  
Mdx Mice ◽  
Dystrophic Muscle ◽  
Macrophage Population ◽  
Cellular Events ◽  
Inflammatory Status ◽  
Inflammatory Phenotype ◽  
Inflammatory Macrophages ◽  
Amp Activated Protein Kinase

ABSTRACT Duchenne muscular dystrophy is a genetic muscle disease characterized by chronic inflammation and fibrosis mediated by a pro-fibrotic macrophage population expressing pro-inflammatory markers. Our aim was to characterize cellular events leading to the alteration of macrophage properties and to modulate macrophage inflammatory status using the gaseous mediator hydrogen sulfide (H2S). Using co-culture experiments, we first showed that myofibers derived from mdx mice strongly skewed the polarization of resting macrophages towards a pro-inflammatory phenotype. Treatment of mdx mice with NaHS, an H2S donor, reduced the number of pro-inflammatory macrophages in skeletal muscle, which was associated with a decreased number of nuclei per fiber, as well as reduced myofiber branching and fibrosis. Finally, we established the metabolic sensor AMP-activated protein kinase (AMPK) as a critical NaHS target in muscle macrophages. These results identify an interplay between myofibers and macrophages where dystrophic myofibers contribute to the maintenance of a highly inflammatory environment sustaining a pro-inflammatory macrophage status, which in turn favors myofiber damage, myofiber branching and establishment of fibrosis. Our results also highlight the use of H2S donors as a potential therapeutic strategy to improve the dystrophic muscle phenotype by dampening chronic inflammation. This article has an associated First Person interview with the first author of the paper.

Contractile efficiency of dystrophic mdx mouse muscle: in vivo and ex vivo assessment of adaptation to exercise of functional end points

2017 ◽  
Vol 122 (4) ◽  
pp. 828-843 ◽  
Author(s):  
Roberta Francesca Capogrosso ◽  
Paola Mantuano ◽  
Anna Cozzoli ◽  
Francesca Sanarica ◽  
Ada Maria Massari ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Damage ◽  
Functional Adaptation ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Chronic Exercise ◽  
Exercise Protocol ◽  
Dystrophic Muscle

Progressive weakness is a typical feature of Duchenne muscular dystrophy (DMD) patients and is exacerbated in the benign mdx mouse model by in vivo treadmill exercise. We hypothesized a different threshold for functional adaptation of mdx muscles in response to the duration of the exercise protocol. In vivo weakness was confirmed by grip strength after 4, 8, and 12 wk of exercise in mdx mice. Torque measurements revealed that exercise-related weakness in mdx mice correlated with the duration of the protocol, while wild-type (WT) mice were stronger. Twitch and tetanic forces of isolated diaphragm and extensor digitorum longus (EDL) muscles were lower in mdx compared with WT mice. In mdx, both muscle types exhibited greater weakness after a single exercise bout, but only in EDL after a long exercise protocol. As opposite to WT muscles, mdx EDL ones did not show any exercise-induced adaptations against eccentric contraction force drop. qRT-PCR analysis confirmed the maladaptation of genes involved in metabolic and structural remodeling, while damage-related genes remained significantly upregulated and angiogenesis impaired. Phosphorylated AMP kinase level increased only in exercised WT muscle. The severe histopathology and the high levels of muscular TGF-β1 and of plasma matrix metalloproteinase-9 confirmed the persistence of muscle damage in mdx mice. Therefore, dystrophic muscles showed a partial degree of functional adaptation to chronic exercise, although not sufficient to overcome weakness nor signs of damage. The improved understanding of the complex mechanisms underlying maladaptation of dystrophic muscle paves the way to a better managment of DMD patients. NEW & NOTEWORTHY We focused on the adaptation/maladaptation of dystrophic mdx mouse muscles to a standard protocol of exercise to provide guidance in the development of more effective drug and physical therapies in Duchenne muscular dystrophy. The mdx muscles showed a modest functional adaptation to chronic exercise, but it was not sufficient to overcome the progressive in vivo weakness, nor to counter signs of muscle damage. Therefore, a complex involvement of multiple systems underlies the maladaptive response of dystrophic muscle.

scholarly journals Cholesterol metabolism is a potential therapeutic target in Duchenne Muscular Dystrophy

2020 ◽  
Author(s):  
F. Amor ◽  
A. Vu Hong ◽  
G. Corre ◽  
M. Sanson ◽  
L. Suel ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mevalonate Pathway ◽  
Cholesterol Metabolism ◽  
Age Groups ◽  
Muscle Disease ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Metabolic Perturbation

AbstractBackgroundDuchenne Muscular Dystrophy (DMD) is a lethal muscle disease detected in approximately 1:5000 male births. DMD is caused by mutations in the DMD gene, encoding a critical protein that link the cytoskeleton and the extracellular matrix in skeletal and cardiac muscles. The primary consequence of the disrupted link between the extracellular matrix and the myofiber actin cytoskeleton is thought to involve sarcolemma destabilization, perturbation of Ca+2 homeostasis, activation of proteases, mitochondrial damage and tissue degeneration. A recently emphasized secondary aspect of the dystrophic process is a progressive metabolic change of the dystrophic tissue; however, the mechanism and nature of the metabolic dysregulation is yet poorly understood. In this study, we characterized a molecular mechanism of metabolic perturbation in DMD.MethodsWe sequenced plasma miRNA in a DMD cohort, comprising of 54 DMD patients treated or not by glucocorticoid, compared to 27 healthy controls, in three age groups. We developed an original approach for the biological interpretation of miRNA dysregulation, and produced a novel hypothesis concerning metabolic perturbation in DMD. We then used the mdx mouse model for DMD for the investigation of this hypothesis.ResultsWe identified 96 dysregulated miRNAs, of which 74 were up- and 22 down-regulated in DMD. We confirmed the dysregulation in DMD of Dystro-miRs, Cardio-miRs and a large number of the DLK1-DIO3 miRNAs. We also identified numerous dysregulated miRNAs, yet unreported in DMD. Bioinformatics analysis of both target and host genes for dysregulated miRNAs predicted that lipid metabolism might be a critical metabolic perturbation in DMD. Investigation of skeletal muscles of the mdx mouse uncovered dysregulation of transcription factors of cholesterol and fatty acid metabolism (SREBP1 and SREBP2), perturbation of the mevalonate pathway, and accumulation of cholesterol. Elevated cholesterol level was also found in muscle biopsies of DMD patients. Treatment of mdx mice with Simvastatin, a cholesterol-reducing agent, normalized these perturbations and partially restored the dystrophic parameters.ConclusionThis investigation supports that cholesterol metabolism and the mevalonate pathway are potential therapeutic targets in DMD.

scholarly journals Metabolomic Analyses Reveal Extensive Progenitor Cell Deficiencies in a Mouse Model of Duchenne Muscular Dystrophy

Metabolites ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 61 ◽  
Author(s):  
Josiane Joseph ◽  
Dong Cho ◽  
Jason Doles
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mouse Model ◽  
Progenitor Cell ◽  
Treatment Options ◽  
Cell Types ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Metabolic Alterations ◽  
Potential Contributor

Duchenne muscular dystrophy (DMD) is a musculoskeletal disorder that causes severe morbidity and reduced lifespan. Individuals with DMD have an X-linked mutation that impairs their ability to produce functional dystrophin protein in muscle. No cure exists for this disease and the few therapies that are available do not dramatically delay disease progression. Thus, there is a need to better understand the mechanisms underlying DMD which may ultimately lead to improved treatment options. The muscular dystrophy (MDX) mouse model is frequently used to explore DMD disease traits. Though some studies of metabolism in dystrophic mice exist, few have characterized metabolic profiles of supporting cells in the diseased environment. Using nontargeted metabolomics we characterized metabolic alterations in muscle satellite cells (SCs) and serum of MDX mice. Additionally, live-cell imaging revealed MDX-derived adipose progenitor cell (APC) defects. Finally, metabolomic studies revealed a striking elevation of acylcarnitines in MDX APCs, which we show can inhibit APC proliferation. Together, these studies highlight widespread metabolic alterations in multiple progenitor cell types and serum from MDX mice and implicate dystrophy-associated metabolite imbalances in APCs as a potential contributor to adipose tissue disequilibrium in DMD.

Talin, vinculin and DRP (utrophin) concentrations are increased at mdx myotendinous junctions following onset of necrosis

1994 ◽  
Vol 107 (6) ◽  
pp. 1477-1483 ◽  
Author(s):  
D.J. Law ◽  
D.L. Allen ◽  
J.G. Tidball
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Cytoskeletal Proteins ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Myotendinous Junction ◽  
Glycoprotein Complex ◽  
Transmembrane Glycoprotein ◽  
Muscle Necrosis ◽  
Myotendinous Junctions

Duchenne muscular dystrophy (DMD) and the myopathy seen in the mdx mouse both result from absence of the protein dystrophin. Structural similarities between dystrophin and other cytoskeletal proteins, its enrichment at myotendinous junctions, and its indirect association with laminin mediated by a transmembrane glycoprotein complex suggest that one of dystrophin's functions in normal muscle is to form one of the links between the actin cytoskeleton and the extracellular matrix. Unlike Duchenne muscular dystrophy patients, mdx mice suffer only transient muscle necrosis, and are able to regenerate damaged muscle tissue. The present study tests the hypothesis that mdx mice partially compensate for dystrophin's absence by upregulating one or more dystrophin-independent mechanisms of cytoskeleton-membrane association. Quantitative analysis of immunoblots of adult mdx muscle samples showed an increase of approximately 200% for vinculin and talin, cytoskeletal proteins that mediate thin filament-membrane interactions at myotendinous junctions. Blots also showed an increase (143%) in the dystrophin-related protein called utrophin, another myotendinous junction constituent, which may be able to substitute for dystrophin directly. Muscle samples from 2-week-old animals, a period immediately preceding the onset of muscle necrosis, showed no significant differences in protein concentration between mdx and controls. Quantitative analyses of confocal images of myotendinous junctions from mdx and control muscles show significantly higher concentrations of talin and vinculin at the myotendinous junctions of mdx muscle. These findings indicate that mdx mice may compensate in part for the absence of dystrophin by increased expression of other molecules that subsume dystrophin's mechanical function.

scholarly journals Laminin-111 protein therapy enhances muscle regeneration and repair in the GRMD dog model of Duchenne muscular dystrophy

2019 ◽  
Vol 28 (16) ◽  
pp. 2686-2695 ◽  
Author(s):  
Pamela Barraza-Flores ◽  
Tatiana M Fontelonga ◽  
Ryan D Wuebbles ◽  
Hailey J Hermann ◽  
Andreia M Nunes ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Strength ◽  
Premature Death ◽  
Muscle Disease ◽  
Muscle Pathology ◽  
Mdx Mouse ◽  
Protein Therapy ◽  
Muscle Fibrosis ◽  
Dog Model

Abstract Duchenne muscular dystrophy (DMD) is a devastating X-linked disease affecting ~1 in 5000 males. DMD patients exhibit progressive muscle degeneration and weakness, leading to loss of ambulation and premature death from cardiopulmonary failure. We previously reported that mouse Laminin-111 (msLam-111) protein could reduce muscle pathology and improve muscle function in the mdx mouse model for DMD. In this study, we examined the ability of msLam-111 to prevent muscle disease progression in the golden retriever muscular dystrophy (GRMD) dog model of DMD. The msLam-111 protein was injected into the cranial tibial muscle compartment of GRMD dogs and muscle strength and pathology were assessed. The results showed that msLam-111 treatment increased muscle fiber regeneration and repair with improved muscle strength and reduced muscle fibrosis in the GRMD model. Together, these findings support the idea that Laminin-111 could serve as a novel protein therapy for the treatment of DMD.

238 TAILORED PIG MODEL OF DUCHENNE MUSCULAR DYSTROPHY

2012 ◽  
Vol 24 (1) ◽  
pp. 231 ◽  
Author(s):  
N. Klymiuk ◽  
C. Thirion ◽  
K. Burkhardt ◽  
A. Wuensch ◽  
S. Krause ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Nuclear Transfer ◽  
Muscle Disease ◽  
Pig Model ◽  
Mdx Mouse ◽  
Cell Clones ◽  
Fatty Replacement ◽  
Dmd Gene ◽  
Dystrophin Protein

Duchenne muscular dystrophy (DMD) is one of the most common genetic diseases in humans, affecting 1 in 3500 boys. It is characterised by progressive muscle weakness and wasting due to mutations in the dystrophin (DMD) gene resulting in absence of dystrophin protein in skeletal muscle. Although curative treatments are currently not available, genetic and pharmacological approaches are under investigation including early-phase clinical trials. Existing animal models in different species (e.g. mdx mouse, GRMD dog) have been instrumental to understand the pathophysiology of DMD, but have several limitations. Importantly, the causative point mutations (mdx mouse: nonsense mutation; GRMD dog: splice mutation) are different from the most common human mutations (out-of-frame deletion of one or several exons of the DMD gene). We used gene targeting in somatic cells and nuclear transfer to generate a genetically tailored pig model of DMD. A bacterial artificial chromosome (BAC) from the porcine DMD gene was modified by recombineering to replace exon 52, resulting in a frame shift in the transcript. Modified BAC were transfected into male neonatal kidney cells, which were screened by quantitative polymerase chain reaction for replacement of exon 52 in the X-linked DMD gene. Eight of 436 cell clones were successfully targeted and 2 of them were used for nuclear transfer. For each of the cell clones, a pregnancy was established by transfer of cloned embryos into recipient gilts. Four piglets of the first litter were live born and killed within 48 h and tissue samples were processed for histological characterisation. Two piglets of the second litter died during birth due to obstetric complications, whereas the other 2 piglets were delivered by Caesarean section and raised in an artificial feeding system. Their serum creatine kinase (CK) levels were grossly elevated. Although both piglets showed reduced mobility compared with age-matched controls, they were able to move and feed on their own. Immunofluorescence staining of dystrophin was negative in muscle fibres of DMD mutant piglets and the complete absence of dystrophin protein was confirmed by immunoblot analysis. Histological examination of biceps femoris muscle from DMD mutant pigs showed a degenerative myopathy with fibre size variation, rounded fibres, central nuclei, fibrosis and fatty replacement of muscle tissue mimicking the hallmarks of the human disease. In conclusion, we generated the first pig model for a genetic muscle disease. The DMD mutant pig appears to be a bona fide model of the human dystrophy as ascertained by absence of the dystrophin protein, elevated serum CK levels and early degenerative changes on muscle histology. Because deletion of exon 52 is one of the most frequent mutations found in human DMD, the exon 52 mutated DMD pig represents an excellent model for testing targeted genetic treatments. This study was supported by the Bayerische Forschungsstiftung.

scholarly journals Function and Genetics of Dystrophin and Dystrophin-Related Proteins in Muscle

2002 ◽  
Vol 82 (2) ◽  
pp. 291-329 ◽  
Author(s):  
Derek J. Blake ◽  
Andrew Weir ◽  
Sarah E. Newey ◽  
Kay E. Davies
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Protein Complex ◽  
Muscle Disease ◽  
Calcium Handling ◽  
Dystrophic Muscle ◽  
Gene Encoding ◽  
Muscle Wasting Disease ◽  
Novel Therapeutic Strategies ◽  
Related Proteins

The X-linked muscle-wasting disease Duchenne muscular dystrophy is caused by mutations in the gene encoding dystrophin. There is currently no effective treatment for the disease; however, the complex molecular pathology of this disorder is now being unravelled. Dystrophin is located at the muscle sarcolemma in a membrane-spanning protein complex that connects the cytoskeleton to the basal lamina. Mutations in many components of the dystrophin protein complex cause other forms of autosomally inherited muscular dystrophy, indicating the importance of this complex in normal muscle function. Although the precise function of dystrophin is unknown, the lack of protein causes membrane destabilization and the activation of multiple pathophysiological processes, many of which converge on alterations in intracellular calcium handling. Dystrophin is also the prototype of a family of dystrophin-related proteins, many of which are found in muscle. This family includes utrophin and α-dystrobrevin, which are involved in the maintenance of the neuromuscular junction architecture and in muscle homeostasis. New insights into the pathophysiology of dystrophic muscle, the identification of compensating proteins, and the discovery of new binding partners are paving the way for novel therapeutic strategies to treat this fatal muscle disease. This review discusses the role of the dystrophin complex and protein family in muscle and describes the physiological processes that are affected in Duchenne muscular dystrophy.

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