Primary muscle cultures (pp6) were isolated as described (Qu et al., 1998 (
link)) from the indicated mouse lines. FoxO3-depleted (FoxO-KO) pp6 cells were prepared from
foxO3+/− mice as previously described (Dentice et al., 2010 (
link)).
C2C12 cells were obtained from ATCC. In some experiments, endogenous T3 and T4 were removed from the FBS by charcoal absorption (Larsen, 1972 (
link)). Transient transfections were performed using
Lipofectamine 2000 (Life Technologies) according to the manufacturer’s instructions. Single myofibers were prepared from the extensor digitorumlongus and gastrocnemius muscles of 6- to 12-week-old mice as previously described (Rosenblatt et al., 1995 (
link)). Pax7
Hi-Lo isolation by FACS has been described elsewhere (Rocheteau et al., 2012 (
link)). Anti-MyoD (sc-304), myogenin (sc-12732), tubulin (sc-8035), and anti-FoxO3 antibodies were purchased from Santa Cruz Biotechnology. Polyclonal anti-MHC antibody (MF-20a) and
anti-Pax7 antibody were from Developmental Studies Hybridoma Bank. Anti-D3 antibody is described elsewhere (Huang et al., 2003 (
link)). Anti-Desmin antibody was from MP Biomedicals (#10519). Anti-total Akt was from Upstate, and
anti-pAkt and
anti-PARP were from Cell Signaling Technology. TUNEL assay was performed using the
ApopTag kit from Millipore. Caspase-3/Caspase-7 activity was measured by using the
CaspaseGlo kit from Promega.
Dentice M., Ambrosio R., Damiano V., Sibilio A., Luongo C., Guardiola O., Yennek S., Zordan P., Minchiotti G., Colao A., Marsili A., Brunelli S., Del Vecchio L., Larsen P.R., Tajbakhsh S, & Salvatore D. (2014). Intracellular Inactivation of Thyroid Hormone Is a Survival Mechanism for Muscle Stem Cell Proliferation and Lineage Progression. Cell Metabolism, 20(6), 1038-1048.