Fig. 6

Elevated SMAD1/5 signaling and BMP gene targets are observed in aged rat sarcopenic muscle. (A) Heatmap for TGFB pathway gene expression profiles in aged rat diaphragm, gastrocnemius, soleus, and tibialis anterior muscles. Tissues were profiled from multiple time points across the lifespan of rats (from 6 to 27 months). For age-related genes (see the original paper for details), the time points where the genes show significant differential expression vs. 6 months are marked by asterisks. Id1-3, BMP target genes, are highlighted in a black box. (B) SMAD1/5 immunoblotting analysis in select rat sarcopenic and non-sarcopenic muscles. Muscle weights for sarcopenic tibialis anterior (or TA) and non-sarcopenic triceps are shown on the left. Phosphorylated SMAD1/5 and total SMAD1 levels for each muscle group are shown on the right. Data are mean ± standard deviation (SD) from the mean. Statistical analyses were conducted with an un-paired t-test. *p ≤.05; **p ≤.01; ***p ≤.001; ****p ≤.0001 compared to control