Figure 3.

The γ-secretase inhibitor DAPT induces a rapid and robust phenotypic conversion of striolar supporting cells into hair cells in neonatal utricles. A, Maximal projection image of a DAPT-treated utricle labeled for oncomodulin (green) and spectrin (red). The striolar region (yellow line) was delineated using oncomodulin as a marker. The line of polarity reversal (white dashed line) was drawn using spectrin labeling of cuticular plates. The image also illustrates the size of the 3000 μm² areas that were quantified by counting preexisting HCs and SHLCs (anterior striola, AS; middle striola, MS; posterior striola, PS; medial extrastriola, MES; lateral extrastriola, LES). B, Higher-magnification image of a DMSO-treated and a DAPT-treated utricle labeled for spectrin (red) and F-actin (green) at the level of the striola. Arrowheads point to the newly generated hair-cell-like cells and arrows point to mature, preexisting hair cells. Scale bars: A, 50 μm; B, 10 μm. C, Quantification of the number of preexisting HCs and SHLCs per 3000 μm² in utricles treated with DAPT or vehicle for the first 30 h and cultured for a total of 72 h.