Fig. 9
CaMKIIβ/βM overexpression normalizes endplate fragmentation in Mbnl1ΔE3/ΔE3 innervated muscle. A AAV-based overexpression strategy to evaluate the role of CaMKIIβ/βM deregulation in Mbnl1ΔE3/ΔE mice. Created with Biorender.com. B mRNA levels of Camk2b in control and Mbnl1ΔE3/ΔE3 TA muscles infected with AAV-GFP, -CaMKIIβ, or -CaMKIIβM. Levels are normalized to Tbp, relative to control innervated muscle and expressed as log2(Fold Change). n = 4 Ctrl and 3 Mbnl1ΔE3/ΔE3 (except in Den, n = 4 IIβM). C, D Specific tetanic force (sP0; C) and late relaxation time (D) upon stimulation of control and Mbnl1ΔE3/ΔE3 EDL muscles infected with AAV-GFP, -CaMKIIβ, or -CaMKIIβM. n = 4/5/6 Ctrl and 3 Mbnl1ΔE3/ΔE3 per group. E Number of fragments per endplate in control and Mbnl1ΔE3/ΔE3 EDL innervated muscles injected with AAV-GFP, -CaMKIIβ, or -CaMKIIβM. n = 5/5/7 Ctrl and 3 Mbnl1ΔE3/ΔE3 per group. F-K mRNA levels of Myog (F, I), Chrna1 (G, J) and Chrng (H, K) in control and Mbnl1ΔE3/ΔE3 TA innervated (F-H) and denervated (3 days; I-K) muscles injected with AAV-GFP, -CaMKIIβ, or -CaMKIIβM. Levels are normalized to Tbp, relative to control innervated muscle and expressed as log2(Fold Change). n = 4 Ctrl and 3 Mbnl1ΔE3/ΔE3 (except for Den IIβM, n = 4). Data are mean ± SEM; *p < 0.05; ** p < 0.01; *** p < 0.001; ****p < 0.0001; two-way ANOVA with Tukey’s post-hoc correction