Fig. 9.

Verteporfin attenuates the effects of GSK3 loss in Drosophila. a Knock down of shaggy (sgg) in nephrocytes prevents Duf translocation to the cell surface and is rescued by verteporfin. Flies were raised at the non-permissive temperature (18 °C, which does not allow sgg RNAi expression) and then cultured for 48 h at either the same temperature, or at the higher temperature (29 °C, which allows sgg RNAi expression). Cells were maintained in the presence or absence of 400 nM verteporfin. Nephrocytes were stained with antisera raised to the slit diaphragm protein Dumbfounded (Duf, cyan) as well as wheatgerm agglutinin (magenta). Duf was expressed at the surface of nephrocytes when RNAi was prevented but surface expression was completely prevented in when sgg RNAi was initiated. The lack of surface expression was rescued by the presence of verteporfin. Scale bar = 50 µm. b High magnification images showing rescue of surface expression by verteporfin Sale bar = 40 µm. c Knock down of shaggy (sgg) in nephrocytes prevents Duf translocation to the cell surface and is rescued by verteporfin. n = 6–7 flies per genotype. ANOVA, **p < 0.01 for sgg TARGET at 29 °C having fewer Duf + ve nephrocytes than other groups. d Verteporfin rescues lithium induced toxicity in nephrocytes. Adult wild-type flies were reared to between 3–7 days of age, dissected to reveal the heart and nephrocytes and cultured for 24 h in the presence or absence of lithium (20 mM), verteporfin (400 nM) or both. Scale bar top panel = 30 μm; bottom panel = 10 μm. e Nephrocyte viability was assessed with the vital stain calcein-AM, with nephrocytes being visualised using wheatgerm agglutinin. Lithium had a significant impact on nephrocyte viability (****p < 0.0001) and this was rescued by the addition of verteporfin (****p < 0.0001). Means compared by one-way ANOVA followed by Tukey’s HSD. n = 12 flies from two independent experiments. f Cartoon showing the effect of podocyte GSK3 loss on hippo signalling. GSK3 deletion increases the expression of Ajuba, preventing the phosphorylation of YAP/TAZ and allowing its translocation into the nucleus. This results in cell cycle re-entry, mitotic catastrophe and ultimately apoptosis. Data are presented as the mean ± SEM