Abstract
In this study we investigate how β-catenin-dependent WNT signalling impacts midbrain dopaminergic neuron (mDA) specification. mDA cultures at day 65 of differentiation responded to 25 days of the tankyrase inhibitor XAV969 (XAV, 100nM) with reduced expression of markers of an A9 mDA phenotype (KCNJ6, ALDH1A1 and TH) but increased expression of the transcriptional repressors NR0B1 and NR0B2. Overexpression of NR0B1 and or NR0B2 promoted a loss of A9 dopaminergic neuron phenotype markers (KCNJ6, ALDH1A1 and TH). Overexpression of NR0B1, but not NR0B2 promoted a reduction in expression of the β-catenin-dependent WNT signalling pathway activator RSPO2. Analysis of Parkinson’s disease (PD) transcriptomic databases shows a profound PD-associated elevation of NR0B1 as well as reduced transcript for RSPO2. We conclude that reduced β-catenin-dependent WNT signalling impacts dopaminergic neuron identity, in vitro, through increased expression of the transcriptional repressor, NR0B1. We also speculate that dopaminergic neuron regulatory mechanisms may be perturbed in PD and that this may have an impact upon both existing nigral neurons and also neural progenitors transplanted as PD therapy.
Highlights
The transcriptional repressors NR0B1 and NR0B2 impact A9 dopaminergic neuronal phenotype had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
We used quantitative reverse transcriptase Polymerase Chain Reaction (PCR) (qPCR) to track the fate of dopaminergic neuronal cultures from day 20 to day 80 of differentiation
There were elevations of α-synuclein (SCNA), Solute Carrier Family 18 Member A2 (SLC18A2 or VMAT2) and tyrosine hydroxylase (TH) (Fig 1). These results are consistent with the idea that maturing cultures reduce expression of early markers, such as Forkhead Box A2 (FOXA2) and LMX1A while increasing expression of markers associated with a more mature dopaminergic neuronal phenotype, TH, SLC18A2 and SCNA
Summary
Parkinson’s disease is a debilitating disease affecting 1–2% of individuals over 50 years of age [1]. The motor symptoms include hypokinesia, muscle rigidity and shaking tremor [2], while the non-motor symptoms include depression, apathy, anxiety, hallucinations, sleep disorders, urinary urgency, nocturia, sexual dysfunction, dysphagia, fecal
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
