Generation of Dopaminergic Neurons from iPSCs for Parkinson’s Cell-Based Therapies and Functional Assessment Methods Evaluation

Abstract: Dopamine is a neurotransmitter or a chemical messenger that is primarily responsible for emotions, motivation, and most importantly, smooth, coordinated movement. In Parkinson’s Disease, dopaminergic neurons are degraded, causing a shortage of dopamine within the human body. With current pharmacological treatments, their ability to alleviate symptoms temporarily is necessary for combating PD, but they do not reverse dopaminergic neuron loss. To further study its pathological mechanisms, stem-cell therapies are widely used to generate dopaminergic neurons in vivo using induced pluripotent stem cells. With their pluripotency and self-renewal capabilities obtained using Oct3/4, Sox2, c-Myc, and Klf4, these cells are manipulated to a dopaminergic neuronal fate using transcription factors such as Lmx1a, FoxA2, Nurr1, and Tyrosine Hydroxylase (TH). Other procedures, such as utilizing dual SMAD inhibition or using 3D organoids for their maturation into neuron progenitor cells, are also widely used as other alternatives, with each method displaying key differences or protocols. This study aims to analyse in vitro validation techniques and in vivo functional assessments, such as microdialysis and the rotation of 6-OHDA rodents, assessing their utility and limitations with safety and efficacy, and ethical complexity. Finally, future research should continue to discover more about methods to underscore its therapeutic potential and continue to address potential inaccuracies with each variable implemented.