Fig. 8.

LIN28B promotes nonmitotic hair cell production in an mTOR-dependent manner. (A) Experimental strategy. Cochlear explant cultures were established from stage P5 Atoh1-nGFP iLIN28B transgenic and Atoh1-nGFP transgenic control littermates. Pregnant dams were fed dox containing food starting at E17.5 and dox was present during culture. EdU (3 µM) and rapamycin (4 ng/mL) or vehicle control DMSO was added at plating. CHIR99021 (3 μM) and LY411575 (5 μM) were added the next day. (B) Rapamycin treatment inhibits hair cell generation in control and LIN28B overexpressing cochlear explants. Shown are representative confocal images of the midapical turn of control and LIN28B overexpressing cochlear explants stained for MYO7A (magenta), Atoh1-nGFP (green), SOX2 (blue), and EdU (red). White asterisks mark newly formed hair cells. (C) Quantification of newly formed hair cells (MYO7A⁺ Atoh1-nGFP⁺ SOX2⁺) in B. Graphed are average values for each animal and the mean ± SD, n = 6 animals per group, two independent experiments, two-way ANOVA with Tukey’s correction was used to calculate P values.