Figure 7

Inhibition of candidate miRNAs alters satellite cell fate. The four candidate miRNAs (miR-16, miR-93, miR-106b, and miR-124) that displayed dynamic expression in satellite cells were inhibited in myofiber-associated satellite cells prior to the first cell division. Transfected cells were assessed 3 or 5 days post myofiber harvest and identified via immunofluorescence as satellite cells by Pax7 expression (A, B) with proliferating satellite cells expressing both Pax7 and MyoD (C, D) and quiescent satellite cells expressing only Pax7 (E, F). The percent of Pax7+ satellite cells decreased between 3 and 5 days in satellite cell populations treated with a scrambled RNA control, however, the relative number of Pax7+ satellite cells remained at similar levels when any candidate miRNA was inhibited (A, B). This increase in satellite cells following miRNA inhibition at 5 days was observed in both proliferating satellite cells (D) and quiescent satellite cells (F) for miR-16, miR-106b, and miR-124 while inhibition of miR-93 resulted in a specific increase in proliferating satellite cells at 5 days (D). Inhibition of two miRNAs, miR-106b and miR-124, resulted in a dramatic increase in quiescent satellite cells by 3 days post myofiber isolation (E) that remains consistent through 5 days post isolation (F).