Figure 5
MyoTACTIC-cultured hMMTs predict skeletal muscle structural and functional responses to pharmacological treatment. (a) Representative confocal images of Day 14 hMMTs treated for 7 days with either vehicle control or increasing doses (1, 10, and 100 nM) of Dexamethasone (left panels), Cerivastatin (middle panels), or IGF-1 (right panels) and immunostained for sarcomeric α-actinin (SAA, red) and Hoechst 33342 (Nuclei, blue). Scale bar 50 µm. (b) Quantification of the dose-dependent effect of Dexamethasone (left panel), Cerivastatin (middle panel), and IGF-1 (right panel) on hMMT myotube diameter. *p < 0.05, ***p < 0.001 (for each treatment, n = minimum of 4 hMMTs from a minimum of 3 muscle patient donors per treatment dose). (c) Bar graph quantification of the tetanus (20 Hz electrical stimuli) contractile force generated by hMMTs treated from Day 7 to 14 with either vehicle (−) or (+) Dexamethasone (10 nM; left panel), Cerivastatin (10 nM; middle panel), and IGF-1 (100 nM; right panel). Ethanol, ddH2O, and 10 mM HCl were vehicle controls for Dexamethasone, Cerivastatin, and IGF-1 respectively. Values are normalized to vehicle-treated results on differentiation Day 14. *p < 0.05, ***p < 0.001 (for each treatment, n = minimum of 8 hMMTs generated from 3 muscle patient donors per treatment condition). In (b,c) values are reported as mean ± SEM. In (b), significance was determined by one-way ANOVA followed by Tukey’s multiple comparisons to compare differences between groups (Dexamethasone and Cerivastatin) or Kruskal Wallis test followed by Dunn’s multiple comparisons to compare differences between groups (IGF-1). In (c), significance was determined by t-test (Dexamethasone and Cerivastatin) or t-test with Welch’s correction (IGF-1).
