Fig. 4.

Knockdown of miR-24-3p increases PAX7-positive proliferating MuSCs in vivo. A Intraperitoneal injection of Ant-24 decreases endogenous miR-24-3p in neonatal skeletal muscle. qRT-PCR values of miR-24-3p normalized to the U6sn values are expressed relative to Ant-NC values. miR-192 was used as an NC. B Ant-24 derepresses Hmga1 and Id3 transcript levels. qRT-PCR of Hmga1 and Id3 on hind leg skeletal muscle normalized to Gapdh, then again to the respective Ant-NC samples. C miR-24-3p level is decreased in the MuSCs isolated from Ant-24-injected neonatal mice. D Confocal images of skeletal muscle harvested 4 h after BrdU labeling from Ant-24- or Ant-NC-injected neonates. Cell proliferation was determined by anti-BrdU antibody (green), the cell surface was marked by LAMININ (red), and nuclei were counterstained with DAPI (blue). E Relative BrdU-positive nuclei per field. Mean ± SD of 10 random fields from five mice. F Confocal microscopy images of Ant-24-injected neonatal skeletal muscles from D immunostained for BrdU (green), PAX7 (red), DAPI (blue), BrdU and PAX7 (orange), and BrdU, Pax7, and DAPI (magenta). Mean ± SD of the samples from five neonatal mice. *P < 0.001. Scale bar: 50 μM