Fig. 6

UDCA rescues mutant TDP43 induced damage to the VAPB-PTPIP1 interaction in cortical neurons and to IP3 receptor mediated delivery of Ca²⁺ to mitochondria. (a) Representative images of VAPB-PTPIP51 PLA signals in neurons transfected with EGFP, EGFP-TDP43-Q331K or EGFP-TDP43-A382T and treated with either vehicle or 62.5 µM UDCA for 24 h. TDP43 was identified via the EGFP tag and cells immunostained for MAP2 (artificially shown in cyan) to confirm neuronal identity. Scale bars = 5 μm. Bar charts show numbers of PLA signals per cell after normalisation to EGFP + vehicle treated control. Data were analysed by one-way ANOVA with Tukey’s post hoc test. N = 30–35 cells from 3 independent experiments. Error bars are SEM, *** p≤0.001. (b) UDCA rescues mutant TDP43 induced disruption IP3 receptor delivery of Ca²⁺ to mitochondria. SH-SY5Y cells were transfected with EGFP control, EGFP-TDP43-Q331K or EGFP-TDP43-A382T and treated with vehicle or 62.5 µM UDCA for 24 h as indicated, and mitochondrial Ca²⁺ levels quantified using Rhod-2 AM. Ca²⁺ release was induced by treatment of cells with oxotremorine-M (OxoM). Representative Rhod-2 AM fluorescence traces are shown on the left with OxoM treatment depicted by shaded area; normalised peak values are shown in the bar charts on the right. Expression of TDP43-Q331K or TDP43-A382T reduced mitochondrial Ca²⁺ levels and this was rescued by UDCA. Data were analysed by one-way ANOVA with Tukey’s post hoc test. N = 32–53 cells from 3 independent experiments. Error bars are SEM; ** p≤0.01, *** p≤0.001, ns not significant