Figure 4
Inhibition of calpain-2 but not calpain-1 attenuates the hTau-induced cleavage of α4 nAChR in hippocampus neurons.
(a,b) The 7 DIV hippocampal neurons were infected with lenti-mCherry-hTau virus or the vector. At 10 DIV, the neurons were treated with 2 μM μ-calpain inhibitor PD151746 (μCalp-I) or 10 μM m-calpain inhibitor (mCalp-I) or the vehicle for 48 h and then the cell lysates were prepared for Western blotting. (c–f) Quantitative analyses showed that application of μCalp-I decreased aCalp-1/Calp-1 ratio (two-way ANOVA, factor infection: F1,8 = 69.642, p < 0.0001; factor drug: F1,8 = 258.146, p < 0.0001; infection × drug: F1,8 = 307.814, p < 0.0001; Tukey’s post hoc test), inhibited calpain-1 activation, but did not block α4 degradation induced by calpain-1 activation (two-way ANOVA, factor infection: F1,8 = 223.775, p < 0.0001; factor drug: F1,8 = 0.003, p = 0.957; infection × drug: F1,8 = 8.841, p = 0.018; Tukey’s post hoc test). Application of mCalp-I inhibited calpain-2 (two-way ANOVA, factor infection: F1,8 = 94.811, p < 0.0001; factor drug: F1,8 = 193.761, p < 0.0001; infection × drug: F1,8 = 203.197, p < 0.0001; Tukey’s post hoc test) and attenuated α4 degradation (two-way ANOVA, factor infection: F1,8 = 25.679, p = 0.0010; factor drug: F1,8 = 20.462, p = 0.0019; infection × drug: F1,8 = 14.5184, p = 0.0052; Tukey’s post hoc test). The data were from at least three independent experiments and expressed as mean ± SEM, **p < 0.01, ***p < 0.001, ****p < 0.0001 vs Vec+Vehicle; ##p < 0.01, ####p < 0.0001 vs hTau+Vehicle.
