Chemical conversion of human lung fibroblasts into neuronal cells.

It has been previously reported that human embryonic fibroblasts and mouse embryonic fibroblasts can be converted into neuronal cells using chemical agents, along with forced expression specific transcriptional factors. However, the materials required for reprogramming in these approaches presents major technical difficulties and safety concerns. The current study investigated whether a cocktail of small molecules can convert human lung fibroblast cells into neurons. The small molecules valproic acid, CHIR99021, DMH1, Repsox, forskolin, Y­27632 and SP600125 (VCHRFYS) were used to induce MRC­5 cells into neuronal cells in vitro. Neuronal markers were analyzed by immunofluorescence staining. The gene profiles were analyzed by reverse transcription­quantitative polymerase chain reaction. MRC­5 is a human lung fibroblast cell line derived from normal lung tissue of a 14­week­old male fetus. The results of the current study demonstrated that MRC­5 fibroblasts can be directly converted into neuronal cells using a cocktail of seven small molecules (VCHRFYS), with a yield of ~90% Tuj1­positive cells after 7 days of induction. Following a further maturation period, these chemically-induced neurons possessed neuronal morphology and expressed multiple neuron­specific genes. In conclusion, a cocktail of small molecules that can convert fibroblasts MRC­5 cells into functional neurons without the exogenous genetic factors was identified, which has the potential to be useful in neurological disease therapy.