Fig. 2: Chronic activation of mTORC1 in aging muscle.
From: Muscle 4EBP1 activation modifies the structure and function of the neuromuscular junction in mice
a Representative confocal images of BTX (green), pS6S240+244 (red), DAPI (blue) and Laminin (white) staining from cross-sections of the gastrocnemius muscle of 6- and 28-month-old male control mice and 12-month-old control and TSC1mKO male mice (6mo Control, n = 3; 28mo Control, n = 6; 12mo Control, n = 3; 12mo TSC1mKO, n = 3). The insets are shown in the bottom panels. Asterisks = intracellular pS6S240+244 in angular, odd-shaped fibers; Hash = intracellular pS6S240+244 accumulation in abnormally enlarged fibers; Open arrow = junctional pS6S240+244; Arrowhead = pS6S240+244 in the nucleus, including central nucleus. Scale bars = 50 μm. b Quantification of the percentage of pS6S240+244-positive myofibers (left panel; statistical significance was determined by one-way ANOVA followed by Tukey’s post-hoc pairwise comparison is used for statistical analysis) and mean CSA of pS6S240+244 -positive (pS6+) and pS6S240+244 -negative (pS6-) fibers (right panel; statistical significance was determined by two-way ANOVA followed by Tukey’s post-hoc pairwise comparison is used for statistical analysis). Sample size: 6mo Control Male, n = 3; 28mo Control Male, n = 6; 12mo Control Male, n = 3; 12mo TSC1mKO Male, n = 3; on average, 800 myofibers were analyzed per mouse. Only a P value of less than 0.05 is labeled in the figure. c Representative images of serial sections stained with BTX (green), DAPI (blue), Laminin (white), and pS6S240+244 (red, left panels) or NCAM (red, right panels) from cross-sections of the gastrocnemius muscle of 28-month-old control male (top panels; n = 6) and 12-month-old TSC1mKO male (bottom panels; n = 3). Asterisks = intracellular pS6S240+244 and NCAM in angular, odd-shaped fibers; Hash = intracellular pS6S240+244 and NCAM accumulation in abnormally enlarged fibers. Scale bars = 20 μm.
