Neuronal differentiation of human induced pluripotent stem (iPS) cells, both in 2D models and 3D systems in vitro, allows for the study of disease pathomechanisms and the development of novel therapies. To verify if the origin of donor cells used for reprogramming to iPS cells can influence the differentiation abilities of iPS cells, peripheral blood mononuclear cells (PBMC) and keratinocytes were reprogrammed to iPS cells using the Sendai viral vector and were subsequently checked for pluripotency markers and the ability to form teratomas in vivo. Then, iPS cells were differentiated into dopaminergic neurons in 2D and 3D cultures. Both PBMC and keratinocyte-derived iPS cells were similarly reprogrammed to iPS cells, but they displayed differences in gene expression profiles and in teratoma compositions in vivo. During 3D organoid formation, the origin of iPS cells affected the levels of FOXA2 and LMX1A only in the first stages of neural differentiation, whereas in the 2D model, differences were detected at the levels of both early and late neural markers FOXA2, LMX1A, NURR1, TUBB and TH. To conclude, the origin of iPS cells may significantly affect iPS differentiation abilities in teratomas, as well as exerting effects on 2D differentiation into dopaminergic neurons and the early stages of 3D midbrain organoid formation.
Keywords: differentiation; dopaminergic neurons; midbrain organoids; origin of iPS cells; teratoma formation.