As a non-differentiated cells, HT22 line could be reprogrammed using a dopaminergic differentiated protocol as it is showed in the follow paper:
Kriks, S., Shim, J.-W., Piao, J., Ganat, Y. M., Wakeman, D. R., Xie, Z., … Studer, L. (2011). Dopamine neurons derived from human ES cells efficiently engraft in animal models of Parkinson’s disease. Nature, 480(7378), 547–551.