To further confirm the lineage of our culture, we observed mRNA expression for TH and the classic midbrain marker, PITX3 (Fig. 1R). All nAChR subunit and marker mRNAs increased significantly upon differentiation from iPSC to midbrain-like DA neuron cultures (ANOVA, p < 0.05) even though there was some variability between iPSC lines derived from different subjects, as depicted by the large error bars shown in Fig. 1Q,R. However there was no significant difference in expression between CHRNA5 variant groups. Therefore, the rs16969968 SNP in CHRNA5 does not affect the generation of the DA cellular phenotype through the dual SMAD inhibition protocol.
