Supplementary Figure 2: Neuromuscular investigations.
From: TDP-43 gains function due to perturbed autoregulation in a Tardbp knock-in mouse model of ALS-FTD
(a) Weights of psychology cohort 2 mice (n = 16 wild-type, 12 TDP−43Q331K/+, 14 TDP-43Q331K/Q331K mice). Comparison by repeated measures two−way ANOVA. (b) TDP−43 immunohistochemistry in motor neurons of 5−month−old mice (n = mice per genotype). Representative images shown. Scale bar, 10μm. (c) Representative examples of NMJ immunostaining in gastrocnemius muscles (scale bar, 20μm) with (d) quantification of innervation in wild−type and TDP43Q331K/Q331K mice at 5 months of age (n = 8 mice per genotype). Comparisons: Innervated: P = 0.528 (ns); denervated: P = 0.127 (ns). (e) Innervation/denervation analysis of gastrocnemius muscles in 18 to 23−month−old wild−type and TDP43Q331K/Q331K mice (n = 3 mice per genotype). Comparisons: Innervated: P = 0.678 (ns); denervated: P = 0.801 (ns)⊡ For (d) and (e) unpaired t test with correction using the Holm−Sidak method. (f) Succinate dehydrogenase enzymatic activity in gastrocnemius muscles from 5−month−old mice (n = 8 mice per genotype). Representative images shown. Scale bar, 200 μm. Error bars for (a,d,e) denote s.e.m. (g) Tetanic force responses to repetitive stimulation at 5, 10 and 20Hz from FDB-tibial nerve preparations. Representative wild−type and TDP43Q331K/Q331K mice are shown. (h) Motor unit number estimates in wild−type and TDP43Q331K/Q331K mice based on inspection (Insp) of traces such as those shown in main Fig. 2g, and extrapolation between average motor unit size of the first four units relative to maximum muscle twitch tension (MUNE) (n = 5 wild−type and 5 TDP-43Q331K/Q331K mice). Comparison: Kruskal−Wallis. (i) Maximum tetanic force in TDP43Q331K/Q331K mice compared with controls (50Hz stimulation) (n = 5 wild−τype and 5 TDP−43Q331K/Q331K mice). Comparison: P = 0.150 (ns); two-tailed Mann−Whitney. (j) Tetanus−twitch ratio (expressed as a percentage of maximum force) (n = 4 wild−type and 5 TDP−43Q331K/Q331K mice). Comparison: P > 0.999 (ns); two-tailed Mann−Whitney. (k,l) Fatigue profiles showing decline in maximum tetanic force with repeated stimulation (50Hz for 1 s every 5 s) in representative TDP43Q331K/Q331K and wild−type mouse FDB preparations. (m) Time constant of decay of tetanic force comparing the muscles tested (n = 4 wild−type and 5 TDP−43Q331K/Q331K mice). Comparison: P>0.999 (ns); two-tailed Mann−Whitney. (n,o) Contractile force measurements with progressively graded stimulation (arbitrary units) from representative wild−type and TDP−43Q331K/Q331K mice (n = 3 mice per genotype). Error bars for (h,i,j,m) represent median and interquartile range.
