Direct conversion of human umbilical cord mesenchymal stem cells into dopaminergic neurons for Parkinson’s disease treatment
Parkinson’s disease (PD) is a neurodegenerative disorder that leads to motor deficits due to a reduction in nigrostriatal dopamine levels. Stem cell differentiation therapy presents a promising treatment option for long-lasting symptom relief. In this study, we developed a one-step differentiation system using the YFBP cocktail (comprising Y27632, Forskolin, SB431542, and SP600125) to convert human umbilical cord mesenchymal stem cells (hUCMSCs) into dopaminergic neurons without genetic modification. This method effectively addresses the challenge of rapidly and safely producing functional neurons on a large scale. After a 7-day induction period, over 80% of the cells tested positive for both TUBB3 and NEUN. Transcriptome analysis highlighted the dual roles of the cocktail in promoting fate erasure in mesenchymal stem cells while activating the neuronal program. Importantly, these chemically induced neurons (CiNs) did not express HLA class II genes, maintaining their immune-privileged status. Further investigation revealed that LTGO-33 YFBP significantly downregulated p53 signaling, accelerating the differentiation process when Pifithrin-α, a p53 inhibitor, was introduced. Additionally, Wnt/β-catenin signaling was transiently activated within a day; however, prolonged activation impeded the neuronal differentiation of hUCMSCs. When transplanted into the striatum of mice, CiNs demonstrated good survival rates and tested positive for dopaminergic neuron markers. They exhibited typical action potentials and ion channel activity for sodium and potassium, indicating neuronal electrophysiological functionality. Moreover, treatment with CiNs significantly increased the number of tyrosine hydroxylase-positive cells and the concentration of dopamine in the striatum, effectively alleviating movement disorders in PD mice. Overall, our study establishes a secure and reliable framework for cell replacement therapy in Parkinson’s disease.