Fig. 4.
SNL induces Fbxo3-dependent CARM1 ubiquitination to decrease K+ channel expression in the dorsal horn. (a) Diagram of the timeline of this experiment. (b) Intrathecal BC-1215 (100 nM, 10 μL, at 4 h after injection) reversed SNL-decreased expression levels of Kcna4 and Kcnd2 mRNA in the ipsilateral dorsal horn. **p < 0.01 versus Sham 7D. ##p < 0.01 versus SNL 7D. ++p < 0.01 versus SNL 7D. Each group has 5 rats. Kcna4, one-way ANOVA, F(3, 16) = 20.95, p < 0.0001. Kcnd2, one-way ANOVA, F(3, 16) = 36.06, p < 0.0001. (c) Intrathecal BC-1215 (100 nM, 10 μL, at 2 h after injection) reversed SNL-decreased expression levels of Kcna4, not Kcnd2, mRNA in the ipsilateral dorsal horn. *p < 0.05, **p < 0.01 versus SNL 7D+Veh 4 h. Each group has 5 rats. Kcna4, one-way ANOVA, F(2, 12) = 8.808, p = 0.0044. Kcnd2, one-way ANOVA, F(2, 12) = 5.412, p = 0.0211. (d) Intrathecal BC-1215 (100 nM, 10 μL, at 4 h after injection) reversed SNL-decreased expression levels of Kv1.4 and Kv4.2 in the ipsilateral dorsal horn. **p < 0.01 versus Sham 7D. #p < 0.05, ##p < 0.01 versus SNL 7D. ++p < 0.01 versus SNL 7D+Veh. Each group has 5 rats. Kv1.4, one-way ANOVA, F(3, 16) = 16.73, p < 0.0001. Kv4.2, one-way ANOVA, F(3, 16) = 14.87, p < 0.0001. (e) Intrathecal BC-1215 (100 nM, 10 μL, at 4 h after injection) reversed SNL-decreased abundance of Kcna4 and Kcnd2 promoter fragments immunoprecipitated by CARM1-specific antibodies in the ipsilateral dorsal horn. **p < 0.01 versus Sham 7D. #p < 0.05, ##p < 0.01 versus SNL 7D. ++p < 0.01 versus SNL 7D+Veh. Each group has 5 rats. Kv1.4, one-way ANOVA, F(3, 16) = 26.59, p < 0.0001. Kv4.2, one-way ANOVA, F(3, 16) = 42.97, p < 0.0001. (f) Representative traces of K+ currents recorded from dorsal horn neurons dissected 7 days after Sham (Sham 7D), SNL operation (SNL 7D) and SNL operation with BC-1215 (SNL 7D + BC-1215, 100 nM, 10 μL, at 4 h after injection). **p < 0.01 versus Sham 7D. #p < 0.05, ##p < 0.01 versus SNL 7D. Each group has 7–8 rats. Two-way ANOVA, group, F(2, 19) = 3.919, p = 0.0376; time, F(15, 285) = 198.1, p < 0.0001; interaction, F(30, 285) = 5.086, p < 0.0001