scholarly journals uPA deficiency exacerbates muscular dystrophy in MDX mice

2007 ◽  
Vol 178 (6) ◽  
pp. 1039-1051 ◽  
Author(s):  
Mònica Suelves ◽  
Berta Vidal ◽  
Antonio L. Serrano ◽  
Marc Tjwa ◽  
Josep Roma ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Inflammatory Cells ◽  
Mdx Mice ◽  
Muscle Dystrophy ◽  
Dystrophic Muscle ◽  
Critical Function ◽  
Upa Receptor ◽  
Muscular Function ◽  
Degenerative Disorder ◽  
Transplantation Experiments

Duchenne muscular dystrophy (DMD) is a fatal and incurable muscle degenerative disorder. We identify a function of the protease urokinase plasminogen activator (uPA) in mdx mice, a mouse model of DMD. The expression of uPA is induced in mdx dystrophic muscle, and the genetic loss of uPA in mdx mice exacerbated muscle dystrophy and reduced muscular function. Bone marrow (BM) transplantation experiments revealed a critical function for BM-derived uPA in mdx muscle repair via three mechanisms: (1) by promoting the infiltration of BM-derived inflammatory cells; (2) by preventing the excessive deposition of fibrin; and (3) by promoting myoblast migration. Interestingly, genetic loss of the uPA receptor in mdx mice did not exacerbate muscular dystrophy in mdx mice, suggesting that uPA exerts its effects independently of its receptor. These findings underscore the importance of uPA in muscular dystrophy.

scholarly journals Utrophin, MHC and M1/M2 macrophages in GRMD dogs

2020 ◽  
Vol 21 ◽  
Author(s):  
Gabriela Noronha de Toledo ◽  
Julieta Rodini Engracia de Moraes
Keyword(s):  
Muscular Dystrophy ◽  
Mhc Class Ii ◽  
Biceps Femoris ◽  
Inflammatory Cells ◽  
Muscle Disease ◽  
Hereditary Diseases ◽  
Golden Retriever ◽  
M2 Macrophages ◽  
Dystrophic Muscle ◽  
One Year

Abstract Muscular dystrophies are hereditary diseases that lead to progressive degeneration of the skeletal musculature. Golden Retriever dogs are used as animal models because they show a hereditary muscle disease similar to muscular dystrophy in humans. Aims: To evaluate the immunostaining of M1 (CD68) and M2 (CD163) macrophages, MHC I, MHC II and, utrophin in muscles of Golden Retriever dogs affected by muscular dystrophy (GRMD). Methods: Samples from 17 male dogs affected by GRMD were divided into GI - dystrophic dogs up to one year of age; and GII - dystrophic dogs over one-year-old. Results: Immunostaining of CD163 was higher than CD68 in both GI and GII. CD68 showed no variation between groups of dystrophic animals. MHC class I immunostaining was most evident in the biceps femoris and triceps brachialis. MHC class II was expressed mildly in four dystrophic muscle types in GI and GII. Utrophin immunostaining was higher in GII. Conclusion: M2 macrophages were one of the main mononuclear inflammatory cells found in dystrophic muscles. The number of M2 in muscles of dogs with GRMD increases with age, linking this cell subtype to permanent muscle damage.

scholarly journals Improvement of Endurance of DMD Animal Model Using Natural Polyphenols

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Clementina Sitzia ◽  
Andrea Farini ◽  
Federica Colleoni ◽  
Francesco Fortunato ◽  
Paola Razini ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Genetic Defect ◽  
Premature Death ◽  
Mdx Mice ◽  
Dystrophic Muscle ◽  
Muscle Fibrosis ◽  
Natural Polyphenols ◽  
Dystrophin Deficiency ◽  
Force Reduction ◽  
Muscular Architecture

Duchenne muscular dystrophy (DMD), the most common form of muscular dystrophy, is characterized by muscular wasting caused by dystrophin deficiency that ultimately ends in force reduction and premature death. In addition to primary genetic defect, several mechanisms contribute to DMD pathogenesis. Recently, antioxidant supplementation was shown to be effective in the treatment of multiple diseases including muscular dystrophy. Different mechanisms were hypothesized such as reduced hydroxyl radicals, nuclear factor-κB deactivation, and NO protection from inactivation. Following these promising evidences, we investigated the effect of the administration of a mix of dietary natural polyphenols (ProAbe) on dystrophic mdx mice in terms of muscular architecture and functionality. We observed a reduction of muscle fibrosis deposition and myofiber necrosis together with an amelioration of vascularization. More importantly, the recovery of the morphological features of dystrophic muscle leads to an improvement of the endurance of treated dystrophic mice. Our data confirmed that ProAbe-based diet may represent a strategy to coadjuvate the treatment of DMD.

Contractile function and low-intensity exercise effects of old dystrophic (mdx) mice

1998 ◽  
Vol 274 (4) ◽  
pp. C1138-C1144 ◽  
Author(s):  
Alan Hayes ◽  
David A. Williams
Keyword(s):  
Muscular Dystrophy ◽  
Contractile Function ◽  
Weight Bearing ◽  
Contractile Properties ◽  
Mdx Mice ◽  
Type I ◽  
Dystrophic Muscle ◽  
Low Intensity ◽  
Duchenne's Muscular Dystrophy ◽  
Low Intensity Exercise

Old mdx mice display a severe myopathy almost identical to Duchenne’s muscular dystrophy. This study examined the contractile properties of old mdxmuscles and investigated any effects of low-intensity exercise. Isometric contractile properties of the extensor digitorum longus (EDL) and soleus muscles were tested in adult (8–10 mo) and old (24 mo, split into sedentary and exercised groups) mdx mice. The EDL and soleus from old mdx mice exhibited decreased absolute twitch and tetanic forces, and the soleus exhibited a >50% decrease in relative forces (13.4 ± 0.4 vs. 6.0 ± 0.9 N/cm2) compared with adult mice. Old mdx muscles also showed longer contraction times and a higher percentage of type I fibers. Normal and mdx mice completed 10 wk of swimming, but mdx mice spent significantly less time swimming than normal animals (7.8 ± 0.4 vs. 15.8 ± 1.1 min, respectively). However, despite their severe dystrophy, mdx muscles responded positively to the low-intensity exercise. Relative tetanic tensions were increased (∼25% and ∼45% for the EDL and soleus, respectively) after the swimming, although absolute forces were unaffected. Thus these results indicate that, even with a dystrophin-deficient myopathy, mdx muscles can still respond to low-intensity exercise. This study shows that the contractile function of muscles of old mdx mice displays many similarities to that of human dystrophic patients and provides further evidence that the use of non-weight-bearing, low-intensity exercises, such as swimming, has no detrimental effect on dystrophic muscle and could be a useful therapeutic aid for sufferers of muscular dystrophy.

scholarly journals Evidence for impaired neurovascular transmission in a murine model of Duchenne muscular dystrophy

2011 ◽  
Vol 110 (3) ◽  
pp. 601-609 ◽  
Author(s):  
Pooneh Bagher ◽  
Dongsheng Duan ◽  
Steven S. Segal
Keyword(s):  
Blood Flow ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Nerve Stimulation ◽  
Murine Model ◽  
Dystrophin Gene ◽  
Mdx Mice ◽  
Response Curves ◽  
Dystrophic Muscle ◽  
Neurovascular Transmission

Duchenne muscular dystrophy (DMD) is a muscle-wasting disease caused by mutations in the dystrophin gene. Little is known about how blood flow control is affected in arteriolar networks supplying dystrophic muscle. We tested the hypothesis that mdx mice, a murine model for DMD, exhibit defects in arteriolar vasomotor control. The cremaster muscle was prepared for intravital microscopy in pentobarbital sodium-anesthetized mdx and C57BL/10 control mice ( n ≥ 5 per group). Spontaneous vasomotor tone increased similarly with arteriolar branch order in both mdx and C57BL/10 mice [pooled values: first order (1A), 6%; second order (2A), 56%; and third order (3A), 61%] with no difference in maximal diameters between groups measured during equilibration with topical 10 μM sodium nitroprusside (pooled values: 1A, 70 ± 3 μm; 2A, 31 ± 3 μm; and 3A, 19 ± 3 μm). Concentration-response curves to acetylcholine (ACh) and norepinephrine added to the superfusion solution did not differ between mdx and C57BL/10 mice, nor did constriction to elevated (21%) oxygen. In response to local stimulation from a micropipette, conducted vasodilation to ACh and conducted vasoconstriction to KCl were also not different between groups; however, constriction decayed with distance ( P < 0.05) whereas dilation did not. Remarkably, arteriolar constriction to perivascular nerve stimulation (PNS) at 2, 4, and 8 Hz was reduced by ∼25–30% in mdx mice compared with C57BL/10 mice ( P < 0.05). With intact arteriolar reactivity to agonists, attenuated constriction to perivascular nerve stimulation indicates impaired neurovascular transmission in arterioles controlling blood flow in mdx mice.

scholarly journals A nitric oxide synthase transgene ameliorates muscular dystrophy in mdx mice

2001 ◽  
Vol 155 (1) ◽  
pp. 123-132 ◽  
Author(s):  
Michelle Wehling ◽  
Melissa J. Spencer ◽  
James G. Tidball
Keyword(s):  
Nitric Oxide ◽  
Muscular Dystrophy ◽  
Nitric Oxide Synthase ◽  
Muscle Membrane ◽  
Mdx Mice ◽  
No Production ◽  
Dystrophic Muscle ◽  
Membrane Injury ◽  
Oxide Synthase

Dystrophin-deficient muscles experience large reductions in expression of nitric oxide synthase (NOS), which suggests that NO deficiency may influence the dystrophic pathology. Because NO can function as an antiinflammatory and cytoprotective molecule, we propose that the loss of NOS from dystrophic muscle exacerbates muscle inflammation and fiber damage by inflammatory cells. Analysis of transgenic mdx mice that were null mutants for dystrophin, but expressed normal levels of NO in muscle, showed that the normalization of NO production caused large reductions in macrophage concentrations in the mdx muscle. Expression of the NOS transgene in mdx muscle also prevented the majority of muscle membrane injury that is detectable in vivo, and resulted in large decreases in serum creatine kinase concentrations. Furthermore, our data show that mdx muscle macrophages are cytolytic at concentrations that occur in dystrophic, NOS-deficient muscle, but are not cytolytic at concentrations that occur in dystrophic mice that express the NOS transgene in muscle. Finally, our data show that antibody depletions of macrophages from mdx mice cause significant reductions in muscle membrane injury. Together, these findings indicate that macrophages promote injury of dystrophin-deficient muscle, and the loss of normal levels of NO production by dystrophic muscle exacerbates inflammation and membrane injury in muscular dystrophy.

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 Amelioration of muscular dystrophy phenotype in mdx mice by inhibition of Flt1

2019 ◽  
Author(s):  
Mayank Verma ◽  
Yuko Shimizu-Motohashi ◽  
Yoko Asakura ◽  
James Ennen ◽  
Jennifer Bosco ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Muscular Dystrophy ◽  
Knockout Mice ◽  
Gene Knockout ◽  
Functional Improvement ◽  
Mdx Mice ◽  
Vascular Density ◽  
Dystrophic Muscle ◽  
Skeletal Muscle Function ◽  
Vegf Signaling

AbstractDuchenne muscular dystrophy (DMD) is an X-linked recessive genetic disease in which the dystrophin coding for a membrane stabilizing protein is mutated. Recently, the vasculature has also shown to be perturbed in DMD and DMD model mdx mice. Data-mining DMD transcriptomics revealed the defects were correlated to a vascular endothelial growth factor (VEGF) signaling pathway. To reveal the relationship between DMD and VEGF signaling, mdx mice were crossed with constitutive (CAG/CreERTM:Flt1LoxP/LoxP) and endothelial cell-specific conditional gene knockout mice (Cdh5CreERT2:Flt1LoxP/LoxP) for Flt1 which is a decoy receptor for VEGF. Previous work demonstrated that heterozygous global Flt1 knockout mice increased vascular density and improved DMD phenotypes when crossed with DMD model mdx and mdx:utrn-/- mice. Here, we showed that while constitutive deletion of Flt1 is detrimental to the skeletal muscle function, endothelial cell-specific Flt1 deletion resulted in increased vascular density and improvement in the DMD-associated phenotype in the mdx mice. These decreases in pathology, including improved muscle histology and function, were recapitulated in mdx mice given anti-FLT1 peptides or monoclonal antibodies, which blocked VEGF-FLT1 binding. The histological and functional improvement of dystrophic muscle by FLT1 blockade provides a novel pharmacological strategy for the potential treatment of DMD.

scholarly journals Defective dystrophic thymus determines degenerative changes in skeletal muscle

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Andrea Farini ◽  
Clementina Sitzia ◽  
Chiara Villa ◽  
Barbara Cassani ◽  
Luana Tripodi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
T Cells ◽  
Muscular Dystrophy ◽  
Inflammatory Cells ◽  
Regulatory Control ◽  
Mdx Mice ◽  
Specific Response ◽  
Molecular Pattern ◽  
Cellular Debris ◽  
Tnf Α

AbstractIn Duchenne muscular dystrophy (DMD), sarcolemma fragility and myofiber necrosis produce cellular debris that attract inflammatory cells. Macrophages and T-lymphocytes infiltrate muscles in response to damage-associated molecular pattern signalling and the release of TNF-α, TGF-β and interleukins prevent skeletal muscle improvement from the inflammation. This immunological scenario was extended by the discovery of a specific response to muscle antigens and a role for regulatory T cells (Tregs) in muscle regeneration. Normally, autoimmunity is avoided by autoreactive T-lymphocyte deletion within thymus, while in the periphery Tregs monitor effector T-cells escaping from central regulatory control. Here, we report impairment of thymus architecture of mdx mice together with decreased expression of ghrelin, autophagy dysfunction and AIRE down-regulation. Transplantation of dystrophic thymus in recipient nude mice determine the up-regulation of inflammatory/fibrotic markers, marked metabolic breakdown that leads to muscle atrophy and loss of force. These results indicate that involution of dystrophic thymus exacerbates muscular dystrophy by altering central immune tolerance.

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 Osteopontin ablation ameliorates muscular dystrophy by shifting macrophages to a pro-regenerative phenotype

2016 ◽  
Vol 213 (2) ◽  
pp. 275-288 ◽  
Author(s):  
Joana Capote ◽  
Irina Kramerova ◽  
Leonel Martinez ◽  
Sylvia Vetrone ◽  
Elisabeth R. Barton ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Muscle Strength ◽  
Macrophage Polarization ◽  
Inflammatory Cells ◽  
Mdx Mice ◽  
Muscle Weight ◽  
Cell Counts ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
And Function

In the degenerative disease Duchenne muscular dystrophy, inflammatory cells enter muscles in response to repetitive muscle damage. Immune factors are required for muscle regeneration, but chronic inflammation creates a profibrotic milieu that exacerbates disease progression. Osteopontin (OPN) is an immunomodulator highly expressed in dystrophic muscles. Ablation of OPN correlates with reduced fibrosis and improved muscle strength as well as reduced natural killer T (NKT) cell counts. Here, we demonstrate that the improved dystrophic phenotype observed with OPN ablation does not result from reductions in NKT cells. OPN ablation skews macrophage polarization toward a pro-regenerative phenotype by reducing M1 and M2a and increasing M2c subsets. These changes are associated with increased expression of pro-regenerative factors insulin-like growth factor 1, leukemia inhibitory factor, and urokinase-type plasminogen activator. Furthermore, altered macrophage polarization correlated with increases in muscle weight and muscle fiber diameter, resulting in long-term improvements in muscle strength and function in mdx mice. These findings suggest that OPN ablation promotes muscle repair via macrophage secretion of pro-myogenic growth factors.

Sign in / Sign up

Export Citation Format

Share Document