Figure 3. Control of acute exercise-induced muscle inflammation by Tregs.
(A) Schema for AEX experiments with DT-induced Treg ablation.
(B) Blood-lactate concentrations measured at rest and immediately after exercise (n=12–13).
(C) Frequency of Tregs after AEX with versus without ablation (n≥5).
(D) Timecourse of number of immunocytes in muscles of DTR- and DTR+ mice (n≥4).
(E) Frequencies of MFs (top) and Ly6Chi MFs (bottom) in muscle.
(F) Left: representative H&E-stained sections of Qd muscles of DTR- and DTR+ mice on d7 after AEX. Arrows indicate inflammatory lesions. Right: summary quantification. n=24 sections; 6 mice.
(G) k-means clustering of transcripts differentially expressed in Qd muscles of DTR- and DTR+ mice before AEX and during recovery (p < 0.05, FDR < 0.05, r2 ≥ 0.65). Numbers in parentheses indicate number of genes within each cluster. Fold-change as compared to d0 controls from each genotype.
(H) RNA-seq analysis of Qd muscles from DTR- and DTR+ mice in sedentary and 2-week exercise-trained conditions (n=2). FC/FC plot overlain with a signature of genes differentially enriched (FC ≥ 2) by recombinant IFNα treatment (69).
(I) FC/FC plot from H overlain with a signature of genes differentially enriched (FC ≥ 2) by recombinant IFNγ treatment (32).
(J) Top: representative flow-cytometric plots of immunocyte populations on d7 AEX. Numbers beside gates indicate frequencies of gated cells among all cells of parent subset. Bottom: summary frequencies and numbers (n≥5).
Summary plots show data (means ± SD) pooled from ≥2 independent experiments.
*p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 by an unpaired Student’s t-test (C and J), two-way ANOVA with Šídák’s multiple comparisons test (D and E; p-value indicates genotype, time interaction), a Wilcoxon signed-rank test (F; lesion frequencies), the Mann-Whitney test (F; lesion areas), or p value computed by the χ2 test (H and I). DT, diphtheria toxin; DTR, diphtheria toxin receptor; NK, natural killer cell; all other abbreviations as per prior figures.