scholarly journals Nitric oxide signalling pathway in Duchenne muscular dystrophy mice: up-regulation of L-arginine transporters

2012 ◽  
Vol 449 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Jayalakshmi Ramachandran ◽  
Joel S. Schneider ◽  
Pierre-Antoine Crassous ◽  
Ruifang Zheng ◽  
James P. Gonzalez ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Soluble Guanylyl Cyclase ◽  
Signalling Pathway ◽  
Mdx Mice ◽  
Compensatory Mechanism ◽  
Double Knockout ◽  
Entry Site ◽  
Protein Levels

DMD (Duchenne muscular dystrophy) is an incurable rapidly worsening neuromuscular degenerative disease caused by the absence of dystrophin. In skeletal muscle a lack of dystrophin disrupts the recruitment of neuronal NOS (nitric oxide synthase) to the sarcolemma thus affecting NO (nitric oxide) production. Utrophin is a dystrophin homologue, the expression of which is greatly up-regulated in the sarcolemma of dystrophin-negative fibres from mdx mice, a mouse model of DMD. Although cardiomyopathy is an important cause of death, little is known about the NO signalling pathway in the cardiac muscle of DMD patients. Thus we used cardiomyocytes and hearts from two month-old mdx and mdx:utrophin−/− (double knockout) mice (mdx:utr) to study key steps in NO signalling: L-arginine transporters, NOS and sGC (soluble guanylyl cyclase). nNOS did not co-localize with dystrophin or utrophin to the cardiomyocyte membrane. Despite this nNOS activity was markedly decreased in both mdx and mdx:utr mice, whereas nNOS expression was only decreased in mdx:utr mouse hearts, suggesting that utrophin up-regulation in cardiomyocytes maintains nNOS levels, but not function. sGC protein levels and activity remained at control levels. Unexpectedly, L-arginine transporter expression and function were significantly increased, suggesting a novel biochemical compensatory mechanism of the NO pathway and a potential entry site for therapeutics.

scholarly journals Soluble guanylate cyclase stimulation mitigates skeletal and cardiac muscle dysfunction in a mdx model of Duchenne muscular dystrophy

2021 ◽  
Author(s):  
Ling Zhang ◽  
Yuanyuan Xu ◽  
Keyvan Yousefi ◽  
Camila I. Irion ◽  
Roger A. Alvarez ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Guanylate Cyclase ◽  
Soluble Guanylate Cyclase ◽  
Signal Propagation ◽  
Guanosine Monophosphate ◽  
Muscle Pathology ◽  
Mdx Mice

AbstractThe impairment of neuronal nitric oxide synthase (nNOS) signaling contributes to disease pathology in the muscle wasting disorder Duchenne muscular dystrophy (DMD). nNOS signal propagation occurs through nitric oxide sensitive soluble guanylate cyclase (sGC), a critical source of cyclic guanosine monophosphate (cGMP) in muscle. Although both nNOS and sGC activity are impaired in DMD patients, little is known about sGC as a therapeutic target. In this study, we tested the hypothesis that stimulating sGC activity with the allosteric agonist BAY41-8543 mitigates striated muscle pathology in the mdx4cv mouse model of DMD. In contrast to DMD patients, mdx mice exhibited greater basal sGC activity than wild type controls with preservation of cGMP levels due partly to upregulation of sGC in some muscles. Stimulating sGC activity in mdx mice with BAY41-8543 substantially reduced skeletal muscle damage, macrophage densities and inflammation and significantly increased resistance to contraction-induced fatigue. BAY41-8543 also enhanced in vivo diaphragm function while reducing breathing irregularities suggesting improved respiratory function. BAY41-8543 attenuated cardiac hypertrophic remodeling, fibrosis and diastolic dysfunction including left atrium enlargement in aged mdx mice. Overall, sGC stimulation significantly mitigated skeletal and cardio-respiratory dysfunction in mdx4cv mice. Importantly, this study provides compelling pre-clinical evidence supporting sGC as a novel target in DMD and the repurposing of FDA-approved sGC stimulators, such as riociguat and veraciguat, as a novel therapeutic approach for DMD.

scholarly journals Dysregulated Autophagy and Mitophagy in a Mouse Model of Duchenne Muscular Dystrophy Remain Unchanged Following Heme Oxygenase-1 Knockout

2021 ◽  
Vol 23 (1) ◽  
pp. 470
Author(s):  
Olga Mucha ◽  
Katarzyna Kaziród ◽  
Paulina Podkalicka ◽  
Kinga Rusin ◽  
Józef Dulak ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mouse Model ◽  
Heme Oxygenase ◽  
Mrna Level ◽  
Mdx Mice ◽  
Heme Oxygenase 1 ◽  
Protein Levels ◽  
Dystrophic Mice

Dysregulation of autophagy may contribute to the progression of various muscle diseases, including Duchenne muscular dystrophy (DMD). Heme oxygenase-1 (HO-1, encoded by Hmox1), a heme-degrading enzyme, may alleviate symptoms of DMD, inter alia, through anti-inflammatory properties. In the present study, we determined the role of HO-1 in the regulation of autophagy and mitophagy in mdx animals, a commonly used mouse model of the disease. In the gastrocnemius of 6-week-old DMD mice, the mRNA level of mitophagy markers: Bnip3 and Pink1, as well as autophagy regulators, e.g., Becn1, Map1lc3b, Sqstm1, and Atg7, was decreased. In the dystrophic diaphragm, changes in the latter were less prominent. In older, 12-week-old dystrophic mice, diminished expressions of Pink1 and Sqstm1 with upregulation of Atg5, Atg7, and Lamp1 was depicted. Interestingly, we demonstrated higher protein levels of autophagy regulator, LC3, in dystrophic muscles. Although the lack of Hmox1 in mdx mice influenced blood cell count and the abundance of profibrotic proteins, no striking differences in mRNA and protein levels of autophagy and mitophagy markers were found. In conclusion, we demonstrated complex, tissue, and age-dependent dysregulation of mitophagic and autophagic markers in DMD mice, which are not affected by the additional lack of Hmox1.

scholarly journals Metformin Increases Sarcolemma Integrity and Ameliorates Neuromuscular Deficits in a Murine Model of Duchenne Muscular Dystrophy

2021 ◽  
Vol 12 ◽  
Author(s):  
Xia Dong ◽  
Tiankun Hui ◽  
Jie Chen ◽  
Zheng Yu ◽  
Dongyan Ren ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Murine Model ◽  
Muscle Function ◽  
Membrane Integrity ◽  
Therapeutic Drug ◽  
Mdx Mice ◽  
Protein Levels ◽  
Progressive Muscle Weakness ◽  
Electron Microscopy Analysis

Duchenne muscular dystrophy (DMD) is a genetic neuromuscular disease characterized by progressive muscle weakness and wasting. Stimulation of AMP-activated protein kinase (AMPK) has been demonstrated to increase muscle function and protect muscle against damage in dystrophic mice. Metformin is a widely used anti-hyperglycemic drug and has been shown to be an indirect activator of AMPK. Based on these findings, we sought to determine the effects of metformin on neuromuscular deficits in mdx murine model of DMD. In this study, we found metformin treatment increased muscle strength accompanied by elevated twitch and tetanic force of tibialis anterior (TA) muscle in mdx mice. Immunofluorescence and electron microscopy analysis of metformin-treated mdx muscles revealed an improvement in muscle fiber membrane integrity. Electrophysiological studies showed the amplitude of miniature endplate potentials (mEPP) was increased in treated mice, indicating metformin also improved neuromuscular transmission of the mdx mice. Analysis of mRNA and protein levels from muscles of treated mice showed an upregulation of AMPK phosphorylation and dystrophin-glycoprotein complex protein expression. In conclusion, metformin can indeed improve muscle function and diminish neuromuscular deficits in mdx mice, suggesting its potential use as a therapeutic drug in DMD patients.

scholarly journals Age-Dependent Dysregulation of Muscle Vasculature and Blood Flow Recovery after Hindlimb Ischemia in the mdx Model of Duchenne Muscular Dystrophy

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 481
Author(s):  
Paulina Podkalicka ◽  
Olga Mucha ◽  
Katarzyna Kaziród ◽  
Iwona Bronisz-Budzyńska ◽  
Sophie Ostrowska-Paton ◽  
...  
Keyword(s):  
Blood Flow ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Blood Vessels ◽  
Mdx Mice ◽  
Hindlimb Ischemia ◽  
Double Positive ◽  
Functional Studies ◽  
Age Dependent ◽  
Dystrophic Mice

Duchenne muscular dystrophy (DMD), caused by a lack of functional dystrophin, is characterized by progressive muscle degeneration. Interestingly, dystrophin is also expressed in endothelial cells (ECs), and insufficient angiogenesis has already been hypothesized to contribute to DMD pathology, however, its status in mdx mice, a model of DMD, is still not fully clear. Our study aimed to reveal angiogenesis-related alterations in skeletal muscles of mdx mice compared to wild-type (WT) counterparts. By investigating 6- and 12-week-old mice, we sought to verify if those changes are age-dependent. We utilized a broad spectrum of methods ranging from gene expression analysis, flow cytometry, and immunofluorescence imaging to determine the level of angiogenic markers and to assess muscle blood vessel abundance. Finally, we implemented the hindlimb ischemia (HLI) model, more biologically relevant in the context of functional studies evaluating angiogenesis/arteriogenesis processes. We demonstrated that both 6- and 12-week-old dystrophic mice exhibited dysregulation of several angiogenic factors, including decreased vascular endothelial growth factor A (VEGF) in different muscle types. Nonetheless, in younger, 6-week-old mdx animals, neither the abundance of CD31+α-SMA+ double-positive blood vessels nor basal blood flow and its restoration after HLI was affected. In 12-week-old mdx mice, although a higher number of CD31+α-SMA+ double-positive blood vessels and an increased percentage of skeletal muscle ECs were found, the abundance of pericytes was diminished, and blood flow was reduced. Moreover, impeded perfusion recovery after HLI associated with a blunted inflammatory and regenerative response was evident in 12-week-old dystrophic mice. Hence, our results reinforce the hypothesis of age-dependent angiogenic dysfunction in dystrophic mice. In conclusion, we suggest that older mdx mice constitute an appropriate model for preclinical studies evaluating the effectiveness of vascular-based therapies aimed at the restoration of functional angiogenesis to mitigate DMD severity.

Have Duchenne Muscular Dystrophy Patients an Increased Cancer Risk?

2021 ◽  
pp. 1-5
Author(s):  
Gian Luca Vita ◽  
Luisa Politano ◽  
Angela Berardinelli ◽  
Giuseppe Vita
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Systematic Investigation ◽  
Mdx Mice ◽  
True Incidence ◽  
Patients With Cancer ◽  
Dmd Gene ◽  
Age Range ◽  
Prevalence Of Cancer

Background: Increasing evidence suggests that Duchenne muscular dystrophy (DMD) gene is involved in the occurrence of different types of cancer. Moreover, development of sarcomas was reported in mdx mice, the murine model of DMD, in older age. So far, nine isolated DMD patients were reported with concomitant cancer, four of whom with rhabdomyosarcoma (RMS), but no systematic investigation was performed about the true incidence of cancer in DMD. Methods: All members of the Italian Association of Myology were asked about the occurrence of cancer in their DMD patients in the last 30 years. Results: Four DMD patients with cancer were reported after checking 2455 medical records. One developed brain tumour at the age of 35 years. Two patients had alveolar RMS at 14 and 17 years of age. The fourth patient had a benign enchondroma when 11-year-old. Conclusion: Prevalence of cancer in general in the Italian DMD patients does not seem to be different from that in the general population with the same age range. Although the small numbers herein presented do not allow definitive conclusion, the frequent occurrence of RMS in DMD patients raises an alert for basic researchers and clinicians. The role of DMD gene in cancer merits further investigations.

scholarly journals Autophagy in the heart is enhanced and independent of disease progression in mus musculus dystrophinopathy models

2019 ◽  
Vol 8 ◽  
pp. 204800401987958
Author(s):  
HR Spaulding ◽  
C Ballmann ◽  
JC Quindry ◽  
MB Hudson ◽  
JT Selsby
Keyword(s):  
Skeletal Muscle ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Disease Progression ◽  
Gene Mutations ◽  
Dystrophin Gene ◽  
Mdx Mice ◽  
Dystrophin Deficiency ◽  
Muscle Wasting Disease ◽  
Dystrophin Protein

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.

scholarly journals Differential Effects of Halofuginone Enantiomers on Muscle Fibrosis and Histopathology in Duchenne Muscular Dystrophy

2021 ◽  
Vol 22 (13) ◽  
pp. 7063
Author(s):  
Sharon Mordechay ◽  
Shaun Smullen ◽  
Paul Evans ◽  
Olga Genin ◽  
Mark Pines ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Motor Coordination ◽  
Mdx Mice ◽  
Cell Viability Assay ◽  
Muscle Fibrosis ◽  
Antifibrotic Therapy ◽  
Racemic Form ◽  
Viability Assay

Progressive loss of muscle and muscle function is associated with significant fibrosis in Duchenne muscular dystrophy (DMD) patients. Halofuginone, an analog of febrifugine, prevents fibrosis in various animal models, including those of muscular dystrophies. Effects of (+)/(−)-halofuginone enantiomers on motor coordination and diaphragm histopathology in mdx mice, the mouse model for DMD, were examined. Four-week-old male mice were treated with racemic halofuginone, or its separate enantiomers, for 10 weeks. Controls were treated with saline. Racemic halofuginone-treated mice demonstrated better motor coordination and balance than controls. However, (+)-halofuginone surpassed the racemic form’s effect. No effect was observed for (−)-halofuginone, which behaved like the control. A significant reduction in collagen content and degenerative areas, and an increase in utrophin levels were observed in diaphragms of mice treated with racemic halofuginone. Again, (+)-halofuginone was more effective than the racemic form, whereas (−)-halofuginone had no effect. Both racemic and (+)-halofuginone increased diaphragm myofiber diameters, with no effect for (−)-halofuginone. No effects were observed for any of the compounds tested in an in-vitro cell viability assay. These results, demonstrating a differential effect of the halofuginone enantiomers and superiority of (+)-halofuginone, are of great importance for future use of (+)-halofuginone as a DMD antifibrotic therapy.

scholarly journals Therapeutic Effect of Camostat Mesilate on Duchenne Muscular Dystrophy in mdx Mice

2003 ◽  
Vol 26 (7) ◽  
pp. 1025-1027 ◽  
Author(s):  
Hitoshi Sawada ◽  
Kazumi Nagahiro ◽  
Yuhsuke Kikukawa ◽  
Susumu Ban ◽  
Reina Kakefuda ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Therapeutic Effect ◽  
Mdx Mice ◽  
Camostat Mesilate

Axonal sprouting in mdx mice and its relevance to cell and gene mediated therapies for Duchenne muscular dystrophy

2003 ◽  
Vol 343 (1) ◽  
pp. 67-69 ◽  
Author(s):  
Humberto Santo Neto ◽  
Airton José Martins ◽  
Elaine Minatel ◽  
Maria Julia Marques
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mdx Mice ◽  
Axonal Sprouting
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