The skeletal muscle phenotype of the DE50-MD dog model of Duchenne muscular dystrophy

Wellcome Open Research

article

John C.W. Hildyard¹  Dominique O. Riddell¹  Rachel C.M. Harron¹  Faye Rawson¹  Emma M.A. Foster¹  Claire Massey¹  Frances Taylor-Brown¹  Dominic J. Wells⁴  Richard J. Piercy¹ 

[1] Comparative Neuromuscular Diseases Laboratory, Department of Clinical Science and Services, Royal Veterinary College;Langford Veterinary Services, University of Bristol;Cave Veterinary Specialists, George's Farm;Department of Comparative Biomedical Sciences, Royal Veterinary College

关键词: DMD;    Duchenne Muscular Dystrophy;    Animal models;    Dog;    DE50-MD;    Biomarkers;    Skeletal Muscle;    Histology;    Gene expression;   

DOI  :  10.12688/wellcomeopenres.18251.1

学科分类：内科医学

来源: Wellcome

【 摘 要 】

Background: Animal models of Duchenne muscular dystrophy (DMD) are essential to study disease progression and assess efficacy of therapeutic intervention, however dystrophic mice fail to display a clinically relevant phenotype, limiting translational utility. Dystrophin-deficient dogs exhibit disease similar to humans, making them increasingly important for late-stage preclinical evaluation of candidate therapeutics. The DE50-MD canine model of DMD carries a mutation within a human ‘hotspot’ region of the dystrophin gene, amenable to exon-skipping and gene editing strategies. As part of a large natural history study of disease progression, we have characterised the DE50-MD skeletal muscle phenotype to identify parameters that could serve as efficacy biomarkers in future preclinical trials.Methods:Vastus lateralis muscles were biopsied from a large cohort of DE50-MD dogs and healthy male littermates at 3-monthly intervals (3-18 months) for longitudinal analysis, with multiple muscles collected post-mortem to evaluate body-wide changes. Pathology was characterised quantitatively using histology and measurement of gene expression to determine statistical power and sample sizes appropriate for future work.Results: DE50-MD skeletal muscle exhibits widespread degeneration/regeneration, fibrosis, atrophy and inflammation. Degenerative/inflammatory changes peak during the first year of life, while fibrotic remodelling appears more gradual. Pathology is similar in most skeletal muscles, but in the diaphragm, fibrosis is more prominent, associated with fibre splitting and pathological hypertrophy. Picrosirius red and acid phosphatase staining represent useful quantitative histological biomarkers for fibrosis and inflammation respectively, while qPCR can be used to measure regeneration (MYH3,MYH8), fibrosis (COL1A1), inflammation (SPP1), and stability of DE50-MD dp427 transcripts.Conclusion: The DE50-MD dog is a valuable model of DMD, with pathological features similar to young, ambulant human patients. Sample size and power calculations show that our panel of muscle biomarkers are of strong pre-clinical value, able to detect therapeutic improvements of even 25%, using trials with only six animals per group.

【 授权许可】

CC BY