Mutation-independent Proteomic Signatures of Pathological Progression in Murine Models of Duchenne Muscular Dystrophy

Abstract

The absence of the dystrophin protein in Duchenne muscular dystrophy (DMD) results in myofiber fragility and a plethora of downstream secondary pathologies. While a variety of experimental therapies are in development, achieving effective treatments for DMD remains exceptionally challenging, not least because the pathological consequences of dystrophin loss are incompletely understood. Here we have performed proteome profiling in tibialis anterior muscles from two murine DMD models (mdx and mdx52) at three ages (8, 16, and 80 weeks of age), all n=3. High-resolution isoelectric focusing liquid chromatography-tandem mass spectrometry (HiRIEF-LC-MS/MS) was used to quantify the expression of 4,974 proteins across all 27 samples. The two dystrophic models were found to be highly similar, whereas multiple proteins were differentially expressed relative to wild-type (C57BL/6) controls at each age. Furthermore, 1,795 proteins were differentially expressed when samples were pooled across ages and dystrophic strains. These included numerous proteins associated with the extracellular matrix and muscle function which have not been reported previously. Pathway analysis revealed multiple perturbed pathways and predicted upstream regulators which together are indicative of crosstalk between inflammatory, metabolic, and muscle growth pathways (e.g. TNF, INFγ, NF-κB, SIRT1, AMPK, PGC-1α, PPARs, ILK, and AKT/PI3K). Up-regulation of CAV3, MVP and PAK1 protein expression was validated in dystrophic muscle by Western blot. Furthermore, MVP was up-regulated during, but not required for, the differentiation of C2C12 myoblasts suggesting that this protein may affect muscle regeneration. This study provides novel insights into mutation-independent proteomic signatures characteristic of the dystrophic phenotype and its progression with aging.

Non-uniform dystrophin re-expression after CRISPR-mediated exon excision in the dystrophin/utrophin double-knockout mouse model of DMD

“…Importantly, the mdx mouse exhibits only a small decrease in lifespan, and impairment of muscle function is relatively mild. Disease in the mdx mouse is similar to that observed in other dystrophin-null models 45 . In contrast, the dKO mouse (a double knock-out of dystrophin and its paralog utrophin) exhibits much more severe pathology, including kyphosis, respiratory difficulties, and premature death (animals typically die ~8-10 weeks of age) [46][47][48][49] .…”

Mass Spectrometric Profiling of Extraocular Muscle and Proteomic Adaptations in the mdx-4cv Model of Duchenne Muscular Dystrophy

“…The heat map illustrates the distribution pattern of changes between normal and dystrophic specimens. In contrast to other sub-types of dystrophin-deficient skeletal muscles [ 31 , 39 , 42 , 84 , 85 , 86 , 87 ], Dp427-lacking EOMs seem to exhibit relatively minor proteome-wide changes.…”

The Increasing Impact of Translational Research in the Molecular Diagnostics of Neuromuscular Diseases

“…The analysis of proteins and the proteome, their activity, interaction, localization and composition, structure and function are some of the aspects proteomics may resolve. Proteomic experiments are generally used to detect specific signatures of disease progression [ 73 ], to unravel pathogenicity mechanisms and detect biomarkers, or to discover targets or processes for therapeutic intervention [ 74 , 75 ]. In 2004, Jaffe et al coined the concept of proteogenomics, a viewpoint focused on the integration of genomic and proteomic data [ 76 ].…”