ABSTRACT
Differentiation of pluripotent and lineage restricted stem cells such as neural stem cells (NSCs) was studied on conducting substrates of various nature without perturbation of the genome with exogenous genetic material or chemical stimuli. Primary mouse adult neural stem cells (NSCs) and P19 pluripotent embryonal (P19 EC) carcinoma cells were used. Expression levels of neuronal markers ß-III-tubulin and neurofilament were evaluated by immunochemistry and flow cytometry. It was shown that the ability of the substrate to induce differentiation directly correlated with its conductivity. Conducting substrates (conducting oxides or doped π-conjugated organic polymers) with different morphology, structure, and conductivity mechanisms all promoted differentiation of NSC and P19 cells into neuronal lineage to a similar degree without use of additional factors such as poly-L-ornithine coating or retinoic acid, as verified by their morphology and upregulation of the neuronal markers but not astrocyte marker GFAP. However, substrates with low conductance below ca. 10(-4) S cm(-2) did not show this ability. Morphology of differentiating cells was visualized by atomic force microscopy. NSCs cells increased ß-III-tubulin expression by 95% and P19 cells by over 30%. Our results suggest that the substrate conductivity is a key factor governing the cell fate. Differentiation of P19 cells into neuronal lineage on conducting substrates was attributed to downregualtion of Akt signaling pathway and increase in expression of dual oxidase 1 (DUOX 1).
