Treatment of Dystrophic mdx Mice with an ADAMTS-5 Specific Monoclonal Antibody Increases the Ex Vivo Strength of Isolated Fast Twitch Hindlimb Muscles

Abstract

Aberrant extracellular matrix synthesis and remodeling contributes to muscle degeneration and weakness in Duchenne muscular dystrophy (DMD). ADAMTS-5, a secreted metalloproteinase with catalytic activity against versican, is implicated in myogenesis and inflammation. Here, using the mdx mouse model of DMD, we report increased ADAMTS-5 expression in dystrophic hindlimb muscles, localized to regions of regeneration and inflammation. To investigate the pathophysiological significance of this, 4-week-old mdx mice were treated with an ADAMTS-5 monoclonal antibody (mAb) or IgG2c (IgG) isotype control for 3 weeks. ADAMTS-5 mAb treatment did not reduce versican processing, as protein levels of the cleaved versikine fragment did not differ between hindlimb muscles from ADAMTS-5 mAb or IgG treated mdx mice. Nonetheless, ADAMTS-5 blockade improved ex vivo strength of isolated fast extensor digitorum longus, but not slow soleus, muscles. The underpinning mechanism may include modulation of regenerative myogenesis, as ADAMTS-5 blockade reduced the number of recently repaired desmin positive myofibers without affecting the number of desmin positive muscle progenitor cells. Treatment with the ADAMTS-5 mAb did not significantly affect markers of muscle damage, inflammation, nor fiber size. Altogether, the positive effects of ADAMTS-5 blockade in dystrophic muscles are fiber-type-specific and independent of versican processing.

Genetic reduction of the extracellular matrix protein versican attenuates inflammatory cell infiltration and improves contractile function in dystrophic mdx diaphragm muscles

“…Two non-overlapping images for each cross-section were captured on an Olympus 1X71 Inverted Fluorescence Microscope with an XM10 camera. To determine the percentage area of fibrosis in the diaphragm cross-sections, planimetric analysis of the digital images was completed using Image-Pro Plus software (Media Cybernetics) 14,98 .…”

“…For analysis of V0/V1 versican and versikine immunoreactivity, four non-overlapping representative digital images were captured with a confocal microscope of each muscle cross-section at 600 × magnification (Olympus Fluoview FV10i). To determine the percentage of muscle cross-section immunoreactive for versican or versikine, planimetric analysis of the digital images was completed using Image-Pro Plus software (Media Cybernetics) 14,98 . To demonstrate that versican synthesis and remodelling are associated with inflammation and regeneration in dystrophic diaphragm muscles, serial sections were used to co-localize versikine with desmin or CD68.…”

“…An iScript cDNA synthesis kit (Bio-Rad) was used to reverse transcribe 0.25 μg of total RNA. Quantitative RT-PCR was performed using IQ SYBR Green Super mix (Bio-Rad) and oligonucleotide primers for the genes of interest (Supplementary Table 1) 98 . cDNA concentrations were determined using Quant-iT OliGreen ssDNA reagent (Thermo Fisher Scientific), and Ct values were normalized to cDNA content.…”

Erratum: Treatment of Dystrophic mdx Mice with an ADAMTS-5 Specific Monoclonal Antibody Increases the Ex Vivo Strength of Isolated Fast Twitch Hindlimb Muscles. Biomolecules 2020, 10, 416

“…The authors wish to make a change to this published paper [ 1 ]. In the original manuscript, there was a mistake in the labeling of the y-axis for Figure 5 B,D.…”

Muscle Twitch Kinetics Are Dependent on Muscle Group, Disease State, and Age in Duchenne Muscular Dystrophy Mouse Models

“…At this sub-maximal force level, the amount of force generated depends on both the stimulation frequency, and the kinetics of muscle contraction and relaxation. There are several studies that include kinetic data in preclinical muscular dystrophy studies, however, these studies were not conducted at physiological temperatures and/or investigated one muscle type of a single dystrophic mouse model (Anderson et al, 1988;Quinlan et al, 1992;Hayes et al, 1993;Lynch et al, 1997;Hayes and Williams, 1998;Chan and Head, 2010;Kiriaev et al, 2018;Addinsall et al, 2020). Although maximal force development is very similar at room and body temperature (Hill, 1972), temperature is a critically important component of kinetics studies; kinetics of contraction and relaxation are much slower at room temperature compared to physiological temperature.…”