Research Article

Induction of Functional Hair-Cell-Like Cells from Mouse Cochlear Multipotent Cells

Figure 2

Gene expression of sphere cells and cells differentiated for 7 and 14 days on poly-L-lysine. (a) Spheres were generated for 5 days in presence of EGF, bFGF, and IGF-1, as indicated. Progenitor cells were generated by subsequent adherent culture for 7 days in poly-L-lysine coated plates in presence of FGF3 and FGF10. On day 7, the resulting progenitor cells were grown adherently on a poly(L-lysine) substratum or a layer of mitotically inactivated chicken utricle stromal cells for 7 days to form hair cells in presence of DAPT. (b) Reverse transcription-polymerase chain reaction (RT-PCR) expression analysis of markers of stem cells and progenitor cells of inner ear cell lineages. The ubiquitously expressed GAPDH is shown as a reference. (c) Expression of the stem cell markers Nestin and Abcg2 and the inner ear progenitor cell marker Pax-2. Spheres: spheres generated from cochlear multipotent cells, 7 d: cells differentiated for 7 days on the poly-L-lysine substratum in vitro, and 14 d: cells differentiated for 14 days on the poly-L-lysine substratum in vitro. Statistically significant differences between groups are indicated by , , and (). (d) Coexpression of the inner ear progenitor cell markers, Pax-2 (red, left) and Pax-8 (green, center), in the sphere cells. Right: merged images (left and center).