Research Paper Volume 6, Issue 10 pp 820—834

Dysregulation of SIRT-1 in aging mice increases skeletal muscle fatigue by a PARP-1-dependent mechanism

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Figure 4. PARP-1 inhibition prevents the H2O2-induced myotube death. Total RNA and cell lysates were isolated from myotubes either treated or not treated with H2O2. (A) Global cellular protein PARylation was determined in the total cell lysate by immunoblots. (B) PARP-1 mRNA and protein levels were determined in total mRNA and cell lysates, respectively. GAPDH was used as a loading control. (C) Myotube survival (%) in the presence or absence of H2O2 was determined by MTT assay at the indicated time-points. (D) Global cellular protein PARylation was determined in total cell lysates from either H2O2-treated or non-treated myotubes either in the presence or absence of PJ34 by immunoblots. (E) Myotube survival (%) was determined by the MTT assay in myotubes treated with the conditions similar to ‘D’. (F) Myotubes were transfected with non-specific or PARP-1-targeting siRNAs. PARP-1 protein abundance were analyzed 48 h after transfection by immunoblots. (G) Global cellular protein PARylation was determined in total cell lysates from either H2O2-treated or non-treated myotubes either in the presence or absence of PARP-1 by immunoblots. (H) Myotube survival (%) was determined by a MTT assay in myotubes treated with the conditions similar to ‘G’. (I) SIRT-1 mRNA (left side) and protein (right side) levels were determined in total mRNA and cell lysates, respectively. (J) PARP-1 acetylation levels were estimated from immunoblots after IP with the conditions similar to ‘G’. (K) PGC-1α acetylation levels were determined in total cell lysates from either myotubes treated with H2O2 or non-treated myotubes with or without PJ34 or RSV by immunoblotting after IP. Global cellular protein PARylation (L) or myotube survival (%) was determined in total cell lysates from either myotubes treated with H2O2 or non-treated myotubes with or without resveratrol. IP, immunoprecipitation; RSV, resveratrol.