Figure 5.

TFEB Controls Energy Balance in Skeletal Muscle

(A) High-intensity exhaustive exercise. To determine exercise capacity, mice were run on a treadmill. During high-intensity exercise, transgenic mice (red) ran more, while TFEB KO mice (gray) ran half as much as WT mice (white). Data are shown as mean ± SE, n = 10; ^∗∗p < 0.01.

(B and C) Energy expenditure (B) and RER (C) were determined during exercise in TFEB KO and WT mice. The mice ran at a fixed speed of 10 m/min and an incline of 20°. The figure shows the mean RER measured at peak oxygen consumption. Data were transformed by Blom’s method to obtain both normally distributed data and normally distributed residual. Two-way ANOVA was used for comparison of RERs in the two groups during the entire resting period, whereas t test was used for comparison of individual time points, n = 8.

(D–F) Blood and muscle metabolites before and after high-intensity exercise in WT (white), TFEB transgenic (red), and TFEB KO mice (gray). Data are shown as mean ± SE, n = 8; ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001.

(G) Enzymatic quantification of muscle glycogen before and after high-intensity exercise in WT (white), TFEB transgenic (red), and TFEB KO mice (gray). Data are shown as mean ± SE, n = 8; ^∗∗p < 0.01.

(H) Periodic acid-Schiff (PAS) staining of cryosections from AAV2.1-GFP, AAV2.1-TFEB transfected, and TFEB KO mice. Inserts show PAS staining after glycogen breakdown. The scale bars represent 100 μm.

(I and J) Quantitative analysis of serum (I) and muscle (J) NEFA before and after high-intensity exercise in TFEB KO (gray) and WT mice (white). Data are shown as mean ± SE, n = 8; ^∗p < 0.05, ^∗∗p < 0.01.

(K) Enzymatic quantification of B-hydroxybutyrate before and after high-intensity exercise in TFEB KO (gray box) and WT mice (white box). Data are shown as mean ± SE, n = 8; ^∗p < 0.05.

(L) TFEB ablation results in a decreased rate of insulin-stimulated GIR. EU clamps were used to assess whole-body insulin sensitivity by determining the GIR required to maintain euglycemia in WT (white) and TFEB KO (gray) mice. Data represent the means ± SE from five to six individual mice per group; ^∗p < 0.05.

(M) TFEB deletion results in a reduction of insulin-stimulated glucose uptake in muscle. Insulin-stimulated glucose uptake into muscle tissues was determined by 2-deoxy-d-[1-¹⁴C]glucose injection during the last 35 min of insulin infusion during the EU clamp. These data represent the means ± SE of five to six mice per group; ^∗p < 0.05. WT, white; TFEB KO, gray.

(N) The amount of glucose conversion to glycogen in GCN muscles from WT (white) and TFEB KO (gray) mice was determined during the EU clamp by infusion of [3-³H]glucose. Data represent the means ± SE from five to six mice per group; ^∗p < 0.05.

(O and P) TFEB KO mice do not show any significant difference in glucose homeostasis of liver or adipose tissue. (O) Glucose uptake into adipose tissue (EPI) and (P) insulin suppression of hepatic glucose output (HGP, liver) were determined during the EU clamp by infusion of 2-deoxy-d-[1-¹⁴C]glucose or [3-³H]glucose infusion into WT mice (white) and TFEB KO (gray) mice. These data represent the means ± SE from five to six mice per group.