Inhibition of Fgf signaling suppresses HC regeneration.
(A) A significant reduction in the number of HCs (HCS1+) regenerated after SU5402 treatment that was dose-dependent. Ctr, time-matched fish without neomycin treatment. (B) A significant reduction in the number of HCs regenerated in hsp70l:dn-fgfr1:GFP (Hsp) zebrafish neuromasts at 32°C or 37°C. AB: wild type AB fish. Ctr, time-matched transgenic fish without neomycin treatment. (C) A significant reduction in proliferation and transdifferentiation derived HCs after 20 μM SU5402 treatment for 72 hrs. ***p<0.001; **p<0.01. For all statistical analysis, n = 15 for each group. Three (for A) and two (for B,C) independent experiments were performed with similar results. (D) Fgf targets etv4 and spry4 were down-regulated by SU5402 (20 μM) in L1 neuromasts during HC regeneration. Scale bars: 10 μm.