Dopaminergic progenitors generated by small molecule approach survived, integrated, and promoted functional recovery in (6-OHDA) mouse model of Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disorder resulting from the loss of dopamine-producing neurons in the brain, causing motor symptoms like tremors and stiffness. Although current treatments like medication and deep brain stimulation can alleviate symptoms, they don't address the root cause of neuron loss. Therefore, cell replacement therapy emerges as a promising treatment strategy. However, the generation of engraftable dopaminergic (DA) cells in clinically relevant quantities is still a challenge. Recent advances in cell reprogramming technologies open up vast possibilities to produce patient-specific cells of a desired type in therapeutic quantities. The main cell reprogramming strategies involve the enforced expression of individual or sets of genes through viral transduction or transfection, or through small molecules, known as the chemical approach, which is a much easier and safer method. In our previous studies, using a small molecule approach (combinations of epigenetic modifiers and SMAD inhibitors such asDorsomorphin and SB431542), we have been able to generate DA progenitors from human mesenchymal stem cells (hMSCs). The aim of this study was to further improve the method for the generation of DA progenitors and to test their therapeutic effect in an animal model of Parkinson's. The results showed that the addition of an autophagy enhancer (AE) to our DA cell induction protocol further increased the yield of DA progenitor cells. The results also showed that DA progenitors transplanted into the mouse model of PD survived, integrated, and improved PD motor symptoms. These data suggest that chemically-produced DA cells can be very promising and safe cellular therapeutics for PD.