Fig. 1.

ADAMTS1 activates satellite cells. a Representative confocal images of myofibers with associated MyoD-negative (upper) and MyoD-positive (lower) YFP+ (Pax7+) satellite cells isolated from extensor digitorum longus (EDL) muscles of tamoxifen-treated Pax7^CreER/+;R26^eYFP/+mice and treated with control (upper) or rADAMTS1 (1.4 μg/ml) (lower). Activated YFP+ (Pax7+) satellite cells were identified by MyoD (red) staining and nuclei were stained with DAPI (blue). Scale bars = 20 μm. b Quantification of the increased proportion of activated satellite cells on myofibers after exposure to rADAMTS1 medium compared to control (n = 75–104 myofiber-associated satellite cells per condition; n = 4 EDL replicates. The mean of the replicates is graphed. P = 0.0023). c Quantification of the number of YFP+ (Pax7+) satellite cells per myofiber across the conditions. Each point on the graph represents one myofiber. *P < 0.05. Error bars represent s.e.m. Statistical significance tested using paired t-tests