Western blotting and behavior examination of HD KI‐140Q mice injected with SM3. a) Western blotting analysis of the striatum of HD KI‐140Q, injected with GFP (Control) or SM3, and wild type (WT) mice injected with GFP at 7 months of age. Antibodies to LAMP1, P62, Beclin 1, and LC3 were used. Vinculin served as a loading control. b) Quantification of the ratios of LAMP1, P62, and Beclin 1 to vinculin or LC3II to LC3I on the western blots. The data were obtained from four independent experiments (n = 4). Data were analyzed by one‐way ANOVA with Dunnett's multiple comparisons test and presented as mean ± SEM. LAMP1: ***P = 0.0003; **P = 0.0021. P62: *P = 0.0266 (WT‐GFP vs KI‐140Q‐GFP); *P = 0.0169 (KI‐140Q‐GFP vs KI‐140Q‐SM3). Beclin 1: *P = 0.0215; ***P = 0.0001. LC3: *P = 0.0203; ***P = 0.0009. c) Quantification of lysosomal enzyme activity using ELISA. n = 4 mice per group. Data were analyzed by one‐way ANOVA with Dunnett's multiple comparisons test and presented as mean ± SEM. **P = 0.0093; *P = 0.0241. d–g) Motor functions of HD KI‐140Q mice injected with GFP (KI‐140Q‐GFP) as control or with SM3 (KI‐140Q‐SM3). Mice were injected at 6 months of age and examined one month later. Mice were examined by rotarod, catwalk, grip strength, and balance beam tests one month after brain injection (n = 12 mice per group). Data were analyzed with two‐tailed Student's t test and presented as mean ± SEM. *P = 0.0211 (rotarod); *P = 0.0405 (catwalk); *P = 0.0232 (balance beam).