Restoration of dystrophin-associated proteins in skeletal muscle of mdx mice transgenic for dystrophin gene

Background Duchenne muscular dystrophy is a muscle wasting disease caused by dystrophin gene mutations resulting in dysfunctional dystrophin protein. Autophagy, a proteolytic process, is impaired in dystrophic skeletal muscle though little is known about the effect of dystrophin deficiency on autophagy in cardiac muscle. We hypothesized that with disease progression autophagy would become increasingly dysfunctional based upon indirect autophagic markers. Methods Markers of autophagy were measured by western blot in 7-week-old and 17-month-old control (C57) and dystrophic (mdx) hearts. Results Counter to our hypothesis, markers of autophagy were similar between groups. Given these surprising results, two independent experiments were conducted using 14-month-old mdx mice or 10-month-old mdx/Utrn± mice, a more severe model of Duchenne muscular dystrophy. Data from these animals suggest increased autophagosome degradation. Conclusion Together these data suggest that autophagy is not impaired in the dystrophic myocardium as it is in dystrophic skeletal muscle and that disease progression and related injury is independent of autophagic dysfunction.

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906. Effective Repetitive Dystrophin Gene Transfer into Skeletal Muscle of Adult mdx Mice Using a Helper-Dependent Adenovirus Vector Expressing the Coxsackievirus and Adenovirus Receptor (CAR) and Dystrophin

Molecular Therapy ◽

10.1016/j.ymthe.2006.08.996 ◽

2006 ◽

Vol 13 ◽

pp. S349

Author(s):

Yuji Uchida ◽

Yasushi Maeda ◽

En Kimura ◽

Makoto Uchino

Keyword(s):

Skeletal Muscle ◽

Gene Transfer ◽

Adenovirus Vector ◽

Dystrophin Gene ◽

Mdx Mice ◽

Coxsackievirus And Adenovirus Receptor ◽

Adenovirus Receptor

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Role of miR-200c in Myogenic Differentiation Impairment via p66Shc: Implication in Skeletal Muscle Regeneration of Dystrophic mdx Mice

Oxidative Medicine and Cellular Longevity ◽

10.1155/2018/4814696 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10 ◽

Cited By ~ 6

Author(s):

Marco D’Agostino ◽

Alessio Torcinaro ◽

Luca Madaro ◽

Lorenza Marchetti ◽

Sara Sileno ◽

...

Keyword(s):

Oxidative Stress ◽

Skeletal Muscle ◽

Myogenic Differentiation ◽

Dystrophin Gene ◽

Muscle Differentiation ◽

Skeletal Muscle Regeneration ◽

Mdx Mice ◽

Pathological Disease ◽

Dependent Mechanism

Duchenne muscular dystrophy (DMD) is a genetic disease associated with mutations of Dystrophin gene that regulate myofiber integrity and muscle degeneration, characterized by oxidative stress increase. We previously published that reactive oxygen species (ROS) induce miR-200c that is responsible for apoptosis and senescence. Moreover, we demonstrated that miR-200c increases ROS production and phosphorylates p66Shc in Ser-36. p66Shc plays an important role in muscle differentiation; we previously showed that p66Shc−/− muscle satellite cells display lower oxidative stress levels and higher proliferation rate and differentiated faster than wild-type (wt) cells. Moreover, myogenic conversion, induced by MyoD overexpression, is more efficient in p66Shc−/− fibroblasts compared to wt cells. Herein, we report that miR-200c overexpression in cultured myoblasts impairs skeletal muscle differentiation. Further, its overexpression in differentiated myotubes decreases differentiation indexes. Moreover, anti-miR-200c treatment ameliorates myogenic differentiation. In keeping, we found that miR-200c and p66Shc Ser-36 phosphorylation increase in mdx muscles. In conclusion, miR-200c inhibits muscle differentiation, whereas its inhibition ameliorates differentiation and its expression levels are increased in mdx mice and in differentiated human myoblasts of DMD. Therefore, miR-200c might be responsible for muscle wasting and myotube loss, most probably via a p66Shc-dependent mechanism in a pathological disease such as DMD.

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Dystrophin-associated proteins are greatly reduced in skeletal muscle from mdx mice.

The Journal of Cell Biology ◽

10.1083/jcb.115.6.1685 ◽

1991 ◽

Vol 115 (6) ◽

pp. 1685-1694 ◽

Cited By ~ 291

Author(s):

K Ohlendieck ◽

K P Campbell

Keyword(s):

Skeletal Muscle ◽

Immunoblot Analysis ◽

Protein Product ◽

Mdx Mouse ◽

Mdx Mice ◽

Normal Density ◽

Mouse Muscle ◽

Glycoprotein Complex ◽

Associated Proteins ◽

Dy Mouse

Dystrophin, the protein product of the human Duchenne muscular dystrophy gene, exists in skeletal muscle as a large oligomeric complex that contains four glycoproteins of 156, 50, 43, and 35 kD and a protein of 59 kD. Here, we investigated the relative abundance of each of the components of the dystrophin-glycoprotein complex in skeletal muscle from normal and mdx mice, which are missing dystrophin. Immunoblot analysis using total muscle membranes from control and mdx mice of ages 1 d to 30 wk found that all of the dystrophin-associated proteins were greatly reduced (80-90%) in mdx mouse skeletal muscle. The specificity of the loss of the dystrophin-associated glycoproteins was demonstrated by the finding that the major glycoprotein composition of skeletal muscle membranes from normal and mdx mice was identical. Furthermore, skeletal muscle membranes from the dystrophic dy/dy mouse exhibited a normal density of dystrophin and dystrophin-associated proteins. Immunofluorescence microscopy confirmed the results from the immunoblot analysis and showed a drastically reduced density of dystrophin-associated proteins in mdx muscle cryosections compared with normal and dy/dy mouse muscle. Therefore, our results demonstrate that all of the dystrophin-associated proteins are significantly reduced in mdx skeletal muscle and suggest that the loss of dystrophin-associated proteins is due to the absence of dystrophin and not due to secondary effects of muscle fiber degradation.

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Effects of prednisolone on the dystrophin-associated proteins in the blood–brain barrier and skeletal muscle of dystrophic mdx mice

Laboratory Investigation ◽

10.1038/labinvest.2013.46 ◽

2013 ◽

Vol 93 (5) ◽

pp. 592-610 ◽

Cited By ~ 17

Author(s):

Roberto Tamma ◽

Tiziana Annese ◽

Roberta F Capogrosso ◽

Anna Cozzoli ◽

Vincenzo Benagiano ◽

...

Keyword(s):

Skeletal Muscle ◽

Blood Brain Barrier ◽

Brain Barrier ◽

Mdx Mice ◽

Blood Brain ◽

Associated Proteins

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Natural History of a Mouse Model Overexpressing the Dp71 Dystrophin Isoform

International Journal of Molecular Sciences ◽

10.3390/ijms222312617 ◽

2021 ◽

Vol 22 (23) ◽

pp. 12617

Author(s):

Kenji Rowel Q. Lim ◽

Md Nur Ahad Shah ◽

Stanley Woo ◽

Harry Wilton-Clark ◽

Pavel Zhabyeyev ◽

...

Keyword(s):

Skeletal Muscle ◽

Tibialis Anterior ◽

Systolic Dysfunction ◽

Dystrophin Gene ◽

Multiple Promoters ◽

Skeletal Muscle Weakness ◽

Associated Proteins ◽

History Of ◽

Dmd Gene

Dystrophin is a 427 kDa protein that stabilizes muscle cell membranes through interactions with the cytoskeleton and various membrane-associated proteins. Loss of dystrophin as in Duchenne muscular dystrophy (DMD) causes progressive skeletal muscle weakness and cardiac dysfunction. Multiple promoters along the dystrophin gene (DMD) give rise to a number of shorter isoforms. Of interest is Dp71, a 71 kDa isoform implicated in DMD pathology by various animal and patient studies. Strong evidence supporting such a role for Dp71, however, is lacking. Here, we use del52;WT mice to understand how Dp71 overexpression affects skeletal and cardiac muscle phenotypes. Apart from the mouse Dmd gene, del52;WT mice are heterozygous for a full-length, exon 52-deleted human DMD transgene expected to only permit Dp71 expression in muscle. Thus, del52;WT mice overexpress Dp71 through both the human and murine dystrophin genes. We observed elevated Dp71 protein in del52;WT mice, significantly higher than wild-type in the heart but not the tibialis anterior. Moreover, del52;WT mice had generally normal skeletal muscle but impaired cardiac function, exhibiting significant systolic dysfunction as early as 3 months. No histological abnormalities were found in the tibialis anterior and heart. Our results suggest that Dp71 overexpression may have more detrimental effects on the heart than on skeletal muscles, providing insight into the role of Dp71 in DMD pathogenesis.

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Nav1.4 Deregulation in Dystrophic Skeletal Muscle Leads to Na+ Overload and Enhanced Cell Death

The Journal of General Physiology ◽

10.1085/jgp.200810024 ◽

2008 ◽

Vol 132 (2) ◽

pp. 199-208 ◽

Cited By ~ 40

Author(s):

Carole Hirn ◽

George Shapovalov ◽

Olivier Petermann ◽

Emmanuelle Roulet ◽

Urs T. Ruegg

Keyword(s):

Skeletal Muscle ◽

Cell Death ◽

Early Death ◽

Mdx Mouse ◽

Mdx Mice ◽

Strongly Correlated ◽

Muscle Degeneration ◽

Voltage Gated ◽

Voltage Gated Sodium Channels ◽

Associated Proteins

Duchenne muscular dystrophy (DMD) is a hereditary degenerative disease manifested by the absence of dystrophin, a structural, cytoskeletal protein, leading to muscle degeneration and early death through respiratory and cardiac muscle failure. Whereas the rise of cytosolic Ca2+ concentrations in muscles of mdx mouse, an animal model of DMD, has been extensively documented, little is known about the mechanisms causing alterations in Na+ concentrations. Here we show that the skeletal muscle isoform of the voltage-gated sodium channel, Nav1.4, which represents over 90% of voltage-gated sodium channels in muscle, plays an important role in development of abnormally high Na+ concentrations found in muscle from mdx mice. The absence of dystrophin modifies the expression level and gating properties of Nav1.4, leading to an increased Na+ concentration under the sarcolemma. Moreover, the distribution of Nav1.4 is altered in mdx muscle while maintaining the colocalization with one of the dystrophin-associated proteins, syntrophin α-1, thus suggesting that syntrophin is an important linker between dystrophin and Nav1.4. Additionally, we show that these modifications of Nav1.4 gating properties and increased Na+ concentrations are strongly correlated with increased cell death in mdx fibers and that both cell death and Na+ overload can be reversed by 3 nM tetrodotoxin, a specific Nav1.4 blocker.

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Abstract 252: The Capsaicin Sensitive Afferent Neuron Innervating Skeletal Muscle is Abnormal in the Mdx Mouse

Circulation Research ◽

10.1161/res.121.suppl_1.252 ◽

2017 ◽

Vol 121 (suppl_1) ◽

Author(s):

Qinglu Li ◽

Mary Garry

Keyword(s):

Blood Pressure ◽

Skeletal Muscle ◽

Muscular Dystrophy ◽

Blood Pressure Response ◽

Dystrophin Gene ◽

Mdx Mouse ◽

Mdx Mice ◽

Afferent Neuron ◽

Afferent Neurons ◽

Left Common Iliac Artery

Duchenne muscular dystrophy (DMD) is a severe type of muscular dystrophy caused by a mutation of the dystrophin gene at locus Xp21, located on the short arm of the X chromosome. Muscle wasting and weakness are common in DMD and in the murine mdx model. We previously demonstrated Group III and IV afferent neurons, which innervate skeletal muscle and control blood pressure and heart rate in response to exercise, are abnormal in settings of ischemia and atrophy; such as cardiomyopathy. We hypothesized that these afferent neurons would also display abnormalities in the mdx mouse. To test this hypothesis, we developed a decerebrate mouse model using 10 wk and 6 mo old male BL10 WT and MDX mice to test mean arterial pressure (MAP) responses to intra-arterial capsaicin (IA-Cap; a specific stimulant of group IV afferent neurons). Mice were anesthetized and MAP was continuously recorded with a pressure transducer in the left carotid artery after which the animal was rendered decerebrate. Following decerebration, anesthesia was discontinued and IA-Cap (0,003-1ug/100ul) was delivered via the left common iliac artery. In rats, we have demonstrated this to be a valid model for evaluating MAP responses to activation of metabolically active afferent neurons. We observed that MAP increased in a dose-related fashion in both 10wk and 6 mo old WT and MDX, while 10 wk old MDX mouse had a normal response, the 6 months MDX mouse response was significantly blunted when compared to WT. To test whether these abnormalities are related to the onset of cardiomyopathy, Echocardiography was performed using 6 months old BL10 WT and MDX mice, no abnormality was found in terms of LV dimensions and function in MDX mice comparing with WT mice. Further studies will be performed to determine whether these abnormalities are inherent to changes in the skeletal muscle of the mdx mouse. We conclude that this murine model displays pressor responses to IA-Cap, similar to the rat and that MDX mice have a blunted blood pressure response to IA-Cap. These results indicate that abnormalities exist within the skeletal muscle afferent neurons in the mdx model.

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Circadian Genes as Exploratory Biomarkers in DMD: Results From Both the mdx Mouse Model and Patients

Frontiers in Physiology ◽

10.3389/fphys.2021.678974 ◽

2021 ◽

Vol 12 ◽

Author(s):

Rachele Rossi ◽

Maria Sofia Falzarano ◽

Hana Osman ◽

Annarita Armaroli ◽

Chiara Scotton ◽

...

Keyword(s):

Skeletal Muscle ◽

Circadian Rhythm ◽

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Expression Profiles ◽

Gene Mutations ◽

Dystrophin Gene ◽

Mdx Mouse ◽

Mdx Mice ◽

Muscle Biopsies

Duchenne muscular dystrophy (DMD) is a rare genetic disease due to dystrophin gene mutations which cause progressive weakness and muscle wasting. Circadian rhythm coordinates biological processes with the 24-h cycle and it plays a key role in maintaining muscle functions, both in animal models and in humans. We explored expression profiles of circadian circuit master genes both in Duchenne muscular dystrophy skeletal muscle and in its animal model, the mdx mouse. We designed a customized, mouse-specific Fluidic-Card-TaqMan-based assay (Fluid-CIRC) containing thirty-two genes related to circadian rhythm and muscle regeneration and analyzed gastrocnemius and tibialis anterior muscles from both unexercised and exercised mdx mice. Based on this first analysis, we prioritized the 7 most deregulated genes in mdx mice and tested their expression in skeletal muscle biopsies from 10 Duchenne patients. We found that CSNK1E, SIRT1, and MYOG are upregulated in DMD patient biopsies, consistent with the mdx data. We also demonstrated that their proteins are detectable and measurable in the DMD patients’ plasma. We suggest that CSNK1E, SIRT1, and MYOG might represent exploratory circadian biomarkers in DMD.

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Global/temporal gene expression in diaphragm and hindlimb muscles of dystrophin-deficient (mdx) mice

AJP Cell Physiology ◽

10.1152/ajpcell.00112.2002 ◽

2002 ◽

Vol 283 (3) ◽

pp. C773-C784 ◽

Cited By ~ 41

Author(s):

Karl Rouger ◽

Martine Le Cunff ◽

Marja Steenman ◽

Marie-Claude Potier ◽

Nathalie Gibelin ◽

...

Keyword(s):

Dystrophin Gene ◽

Diaphragm Muscle ◽

Mdx Mouse ◽

Mdx Mice ◽

First Year ◽

Temporal Gene Expression ◽

Cell Functions ◽

Hindlimb Muscles ◽

Genes Encoding ◽

Dystrophin Protein

The mdx mouse is a model for human Duchenne muscular dystrophy (DMD), an X-linked degenerative disease of skeletal muscle tissue characterized by the absence of the dystrophin protein. The mdx mice display a much milder phenotype than DMD patients. After the first week of life when all mdx muscles evolve like muscles of young DMD patients, mdx hindlimb muscles substantially compensate for the lack of dystrophin, whereas mdx diaphragm muscle becomes progressively affected by the disease. We used cDNA microarrays to compare the expression profile of 1,082 genes, previously selected by a subtractive method, in control and mdx hindlimb and diaphragm muscles at 12 time points over the first year of the mouse life. We determined that 1) the dystrophin gene defect induced marked expression remodeling of 112 genes encoding proteins implicated in diverse muscle cell functions and 2) two-thirds of the observed transcriptomal anomalies differed between adult mdx hindlimb and diaphragm muscles. Our results showed that neither mdx diaphram muscle nor mdx hindlimb muscles evolve entirely like the human DMD muscles. This finding should be taken under consideration for the interpretation of future experiments using mdx mice as a model for therapeutic assays.

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