Sox6 and Otx2 Control the Specification of Substantia Nigra and Ventral Tegmental Area Dopamine Neurons

Distinct midbrain dopamine (mDA) neuron subtypes are found in the substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA), but it is mainly SNc neurons that degenerate in Parkinson’s disease. Interest in how mDA neurons develop has been stimulated by the potential use of stem cells in therapy or disease modeling. However, very little is known about how specific dopaminergic subtypes are generated. Here, we show that the expression profiles of the transcription factors Sox6, Otx2, and Nolz1 define subpopulations of mDA neurons already at the neural progenitor cell stage. After cell-cycle exit, Sox6 selectively localizes to SNc neurons, while Otx2 and Nolz1 are expressed in a subset of VTA neurons. Importantly, Sox6 ablation leads to decreased expression of SNc markers and a corresponding increase in VTA markers, while Otx2 ablation has the opposite effect. Moreover, deletion of Sox6 affects striatal innervation and dopamine levels. We also find reduced Sox6 levels in Parkinson’s disease patients. These findings identify Sox6 as a determinant of SNc neuron development and should facilitate the engineering of relevant mDA neurons for cell therapy and disease modeling. [Display omitted] •Transcription factor expression distinguishes dopamine neural progenitor populations•Sox6 is important for the specification of substantia nigra dopamine neurons•Sox6 expression is restricted by Otx2 in dopamine neural progenitors Panman et al. provide detailed insight into how distinct subtypes of dopamine neurons are generated, including those that are particularly affected in Parkinson’s disease. They show that the transcription factor Sox6 promotes the generation of the most vulnerable type of dopamine neurons in the substantia nigra. Expression of Sox6 is also shown to be diminished in Parkinson’s disease. This knowledge should prove important for the development of stem cell engineering of dopamine neurons for cell replacement therapy.