Stem cell potential in Parkinson's disease and molecular factors for the generation of dopamine neurons

Parkinson's disease (PD) involves the loss of dopamine (DA) neurons, making it the most expected neurodegenerative disease to be treated by cell replacement therapy. Stem cells are a promising source for cell replacement therapy due to their ability to self-renew and their pluripotency/multipotency that allows them to generate various types of cells. However, it is challenging to derive midbrain DA neurons from stem cells. Thus, in this review, I will discuss the molecular factors that are known to play critical roles in the generation and survival of DA neurons. The developmental process of DA neurons and functions of extrinsic soluble factors and homeodomain proteins, forkhead box proteins, proneural genes, Nurr1 and genes involved in epigenetic control are discussed. In addition, different types of stem cells that have potential for future cell replacement therapy are reviewed.

Research Highlights
► Parkinson's disease involves loss of dopamine neurons.
► Stem cells are a promising cell source for cell replacement.
► Molecular factors involved in the generation of dopamine neurons include soluble extrinsic factors, homeodomain proteins, proneural genes, Nurr1, Fox proteins and genes involved in epigenetic control.
► Potential stem cells for cell therapy include neural stem cells, embryonic stem cells and induced pluripotent stem cells.