Fig. 4
MN-Tdp-43∆NLS expression causes muscle atrophy and gait deficits in Tdp-43 mutant mice. (A) Representative live-mice images showing abnormal hindlimb reflexes in 12-month-old MN-Tdp-43ΔNLS mice (N = 6) but not sham mice (N = 5). (B-C) IB images exhibiting levels of high-molecular weight (MW) Tdp-43 and pTdp-43 (S409/410), and pathological 25 kDa fragment of Tdp-43. Gapdh served as the loading control (B). (C) Quantitation of normalized protein levels in fold changes by multiple paired t-tests. *, P < 0.05. (D) Hematoxylin–Eosin (H&E) staining of sham and MN-Tdp-43ΔNLS mice soleus (I-II) tissues. IHC staining with anti-phosphorylated Tdp-43 (S409/410) antibody in soleus muscle tissues (III-IV). Scale bar = 50 µm. The inset image displays cytosolic pTdp-43 staining in muscle cells. (E–F) IB analysis of Titin [full-length: FL; Fragment of 25 kDa: Frag. (25 kDa)] and Stmn2 levels in soleus muscle samples from sham (N = 5) and MN-Tdp-43ΔNLS (N = 6) mice. α-Tubulin served as the loading control (E). (F) Comparisons of normalized Titin (FL & Frag.) and Stmn2 levels between the two groups using multiple paired t-tests or Welch’s t-test. Data are expressed as mean ± SD. **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. (G) Rotarod testing to assess the latency to fall (seconds) for MN-Tdp-43ΔNLS and sham mice (N = 6 mice/group) analyzed by multiple paired t-tests. ns, non-significant; *, P < 0.05. DigiGait analyses of MN-Tdp-43ΔNLS versus sham mice (H) gait symmetry; (I) hindlimb paw area (cm2); (J) stance-to-swing ratio; and (K) stride length (cm). N = 6 mice/group. Data are expressed as mean ± SEM and analyzed by multiple paired t-tests. *, P < 0.05; ***, P < 0.001