Project description:Eosinophils are implicated in the development of many chronic diseases. However, their function in muscular dystrophy is understudied. Here we demonstrate that muscle hyper-eosinophilia could be a marker of poor outcomes in Duchenne Muscular Dystrophy.
Project description:Large animal models for Duchenne muscular dystrophy (DMD) are indispensible for preclinical evaluation of novel diagnostic procedures and treatment strategies. To evaluate functional consequences of Duchenne muscular dystrophy (DMD) in skeletal muscle and myocardium, we used a new genetically engineered dystrophin KO pig model displaying hallmarks of human DMD. Heart and skeletal muscle tissue samples of DMD pigs and wild-type (WT) controls at three different ages were analyzed by label-free proteomics.
Project description:Canine muscular dystrophy (CXMDJ) is a dog model of the lethal X-linked muscle disorder Duchenne muscular dystrophy (DMD), which is caused by loss of dystrophin. Gene expression profile was analyzed in the diaphragm muscles of normal Beagle dogs and CXMDJ before and 1 hour after initial respiration.
Project description:Duchenne muscular dystrophy (DMD) is a genetic disease that results in the death of affected boys by early adulthood.The genetic defect responsible for DMD has been known for over 25 years, yet at present there is neither cure nor effective treatment for DMD. During early disease onset, the mdx mouse has been validated as an animal model for DMD and use of this model has led to valuable but incomplete insights into the disease process. For example, immune cells are thought to be responsible for a significant portion of muscle cell death in the mdx mouse; however, the role and time course of the immune response in the dystrophic process have not been well described. In this paper we constructed a simple mathematical model to investigate the role of the immune response in muscle degeneration and subsequent regeneration in the mdx mouse model of Duchenne muscular dystrophy. Our model suggests that the immune response contributes substantially to the muscle degeneration and regeneration processes. Furthermore, the analysis of the model predicts that the immune system response oscillates throughout the life of the mice, and the damaged fibers are never completely cleared.
Project description:Skeletal muscle wasting results from numerous pathological conditions impacting both the musculoskeletal and nervous systems. A unifying feature of these pathologies is the upregulation of members of the E3 ubiquitin ligase family, resulting in increased proteolytic degradation of target proteins. Despite the critical role E3 ubiquitin ligases in regulating muscle mass, the specific proteins they target for degradation and the mechanisms by which they regulate skeletal muscle homeostasis remain ill-defined. Here, using zebrafish loss of function models combined with in vivo cell biology and proteomic approaches, we identified the endoplasmic reticulum chaperone, BiP, as a novel target of the E3 ubiquitin ligase atrogin-1. A loss in atrogin-1 results in an accumulation of BiP, leading to impaired mitochondrial dynamics and a subsequent loss in muscle fibre integrity. We further implicate a disruption in atrogin-1 mediated BiP regulation in the pathogenesis of Duchenne Muscular Dystrophy. We reveal that BiP is not only upregulated in Duchenne Muscular Dystrophy, but its inhibition using pharmacological strategies, or by upregulating atrogin-1, significantly ameliorates pathology in a zebrafish model of Duchenne Muscular Dystrophy. Collectively, our data implicates a novel disease axis in the pathogenesis of Duchenne Muscular Dystrophy, and highlights atrogin-1’s essential role in maintaining muscle homeostasis.
Project description:In order to understand the chronic hypoxia (CH) effect upon the absence of dystrophin, Drosophila melanogaster wild type and the model for DMD (dmDys), in which all dystrophins expression was knocked out by iRNA, were exposed to high altitude hypoxia (hypobaric hypoxia) during a 16-day climbing period reaching the summit of Mount McKinley (6194 meters above sea level). Furthermore, dmDys and Drosophila wild type were exposed to normobaric hypoxia (hypoxic chamber) following the same oxygen levels observed during the climbing expedition and to normoxic conditions for comparison. Affymetrix GeneChip® profiling was performed for individual flies from each experimental group. CH-dmDys differentially expressed 1281 genes, whereas control group differentially expressed 57 genes. Eight heat shock protein genes detected in the CH-dmDys microarray study were down-regulated, instead of up-regulated as seen in wild type hypoxic flies. This result suggests a differential gene expression response to CH, which could affect muscle performance.These results suggest that dmDys is more sensitive to CH due to reduced muscle function and hypoxic stress response.