Figure 8

DNM2 inhibition rescues the mtm cholestatic phenotype.

A targeted panel of chemicals was tested in mtm zebrafish, using the BODIPY assay as a screen for the cholestatic liver phenotype. For each chemical, the percentage of mtm zebrafish with positive staining in the gallbladder was measured as the readout (n = 10 per trial, with 1 replicate per trial). (A) Two DNM2 inhibitors, Dynasore (green arrow) and Dyngo-4a (pink arrow), were among the chemicals that produced the highest percentage of BODIPY⁺ larvae. (B) Validation of Dynasore combining 3 independent replicates of 10 larvae per replicate. Dynasore-treated mtm larvae had improved bile flux compared with their DMSO-treated mtm siblings (Dynasore = 30.6%, DMSO = 3.67%, P = 0.019, by 2-sided Fisher’s exact test) and did not differ significantly from their WT DMSO-treated siblings (WT percentage = 56.7%, Dynasore percentage = 30.6%, P = 0.13, 2-sided Fisher’s exact test). (C) Dynasore partially restored canalicular structure and transporter expression. Coimmunostaining was performed on whole-mount embryos either exposed to DMSO or treated with Dynasore. As expected, in DMSO-treated mtm zebrafish, essentially no Mdr1 staining was appreciated. In Dynasore-treated larvae, however, there was robust reexpression of Mdr1 and proper colocalization with Rab11. Scale bars: 20 μm.