Generation of a Pure Culture of Neuron-like Cells with a Glutamatergic Phenotype from Mouse Astrocytes

Astrocyte-to-neuron reprogramming is a promising therapeutic approach for treatment of neurodegenerative diseases. The use of small molecules as an alternative to the virus-mediated ectopic expression of lineage-specific transcription factors negates the tumorigenic risk associated with viral genetic manipulation and uncontrolled differentiation of stem cells. However, because previously developed methods for small-molecule reprogramming of astrocytes to neurons are multistep, complex, and lengthy, their applications in biomedicine, including clinical treatment, are limited. Therefore, our objective in this study was to develop a novel chemical-based approach to the cellular reprogramming of astrocytes into neurons with high efficiency and low complexity. To accomplish that, we used C8-D1a, a mouse astrocyte cell line, to assess the role of small molecules in reprogramming protocols that otherwise suffer from inconsistencies caused by variations in donor of the primary cell. We developed a new protocol by which a chemical mixture formulated with Y26732, DAPT, RepSox, CHIR99021, ruxolitinib, and SAG rapidly and efficiently induced the neural reprogramming of astrocytes in four days, with a conversion efficiency of 82 ± 6%. Upon exposure to the maturation medium, those reprogrammed cells acquired a glutaminergic phenotype over the next eleven days. We also demonstrated the neuronal functionality of the induced cells by confirming KCL-induced calcium flux.