Year: 2015
Type: article
Abstract: BACKGROUND: Systemic delivery of anti-sense oligonucleotides to Duchenne muscular dystrophy (DMD) patients to induce de novo dystrophin protein expression in muscle (exon skipping) is a promising therapy. Treatment with Phosphorodiamidate morpholino oligomers (PMO) lead to shorter de novo dystrophin protein in both animal models and DMD boys who otherwise lack dystrophin; however, restoration of dystrophin has been observed to be highly variable. Understanding the factors causing highly variable induction of dystrophin expression in pre-clinical models would likely lead to more effective means of exon skipping in both pre-clinical studies and human clinical trials. METHODS: In the present study, we investigated possible factors that might lead to the variable success of exon skipping using morpholino drugs in the mdx mouse model. We tested whether specific muscle groups or fiber types showed better success than others and also correlated residual PMO concentration in muscle with the amount of de novo dystrophin protein 1 month after a single high-dose morpholino injection (800 mg/kg). We compared the results from six muscle groups using three different methods of dystrophin quantification: immunostaining, immunoblotting, and mass spectrometry assays. RESULTS: The triceps muscle showed the greatest degree of rescue (average 38±28 % by immunostaining). All three dystrophin detection methods were generally concordant for all muscles. We show that dystrophin rescue occurs in a sporadic patchy pattern with high geographic variability across muscle sections. We did not find a correlation between residual morpholino drug in muscle tissue and the degree of dystrophin expression. CONCLUSIONS: While we found some evidence of muscle group enhancement and successful rescue, our data also suggest that other yet-undefined factors may underlie the observed variability in the success of exon skipping. Our study highlights the challenges associated with quantifying dystrophin in clinical trials where a single small muscle biopsy is taken from a DMD patient.
Source: Skeletal Muscle
Authors: Maria Candida Vila, Margaret Benny Klimek, James S. Novak, Sree Rayavarapu, Kitipong Uaesoontrachoon, Jessica F. Boehler, Alyson A. Fiorillo, Marshall W. Hogarth, Aiping Zhang, Conner Shaughnessy, Heather Gordish-Dressman, Umar Burki, Volker Straub, Qi Long Lu, Terence A. Partridge, Kristy J. Brown, Yetrib Hathout, John van den Anker, Eric P. Hoffman, Kanneboyina Nagaraju
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $2,890
Funders: U.S. Department of Defense, Muscular Dystrophy Association, National Institutes of Health, Medical Research Council, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Center for Medical Rehabilitation Research
Awards: Wellstone Muscular Dystrophy Center: Children's Nat'l Med Ctr, G2355214339, G3780238105, G3782417240, G4119534169, G4366394422, G5225823896, G5850682332, TRANSLATIONAL RESEARCH FOR MUSCULAR DYSTROPHY, Preclinical drug trial in mouse models of inflammation, G7030668850, G78058795, PRE-CLINICAL RESEARCH ON TOLL LIKE RECEPTORS IN DMD AND TRANSLATIONAL RESEARCH ADVISORY COMMITTEE OF THE TREAT-NMD NETWORK, DUCHENNE MUSCULAR DYSTROPHY TRANSLATIONAL RESEARCH PROGRAM, G9000006919, G9000032593
OpenAlex ID: W2185895765