Rapid generation of ventral A9-like dopaminergic neurons from patterned iPSCs

In vitro modelling of highly vulnerable nigral dopaminergic (DA) neuronal subtypes in Parkinsons disease (PD), is necessary for studying disease mechanisms. Here, we optimized a new approach by expressing the pioneer neurogenic transcription factor, Achaete-scute-like 1 (Ascl1), implicated in determining dopaminergic fate. Sequential small-molecule patterning of iPSCs into early floor plate mesencephalic progenitors, followed by inducible Ascl1 expression, rapidly differentiates midbrain DA neurons. Immunocytochemistry and transcriptomic analysis of these patterned Ascl1-driven DA neurons (PA-DANs) confirmed midbrain-lineage specificity. Importantly, we found an enrichment of DA subpopulations that corresponded to the adult human ventral SOX6-positive A9 DA subtypes vulnerable in PD. Furthermore, we combined these ventral A9-like PA-DANs with human iPSC-derived midbrain astrocytes and microglia in defined ratios to generate mature 3D A9-like assembled organoids that display characteristic spontaneous neuronal activity and electrical propagation along the axon. Our method efficiently generates a mature and functional A9-like DA neuronal platform to study PD. HighlightsO_LISequential midbrain patterning and Ascl1 expression accelerates DA differentiation C_LIO_LIPA-DANs resemble human adult ventral A9-like DA subtypes vulnerable in PD C_LIO_LI3D assembled organoids show mature identity of PA-DANs, iAstrocytes and iMicroglia C_LIO_LIPA-DANs matured in 3D organoids show neuronal network activity within weeks C_LI eTOC blurbIn this study, Ullian and colleagues have developed a rapid method to differentiate dopaminergic neurons, using small molecules to generate early floor plate mesencephalic progenitors from human iPSCs and sequentially expressing a pioneer transcription factor, Ascl1, that accelerates uniform dopaminergic neurogenesis. Patterned Ascl1-driven dopaminergic neurons (PA-DANs) in 2D and 3D assembled organoids serve as a platform to study Parkinsons disease O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=182 SRC="FIGDIR/small/685897v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@1d83eb3org.highwire.dtl.DTLVardef@1fc7fa5org.highwire.dtl.DTLVardef@2033e3org.highwire.dtl.DTLVardef@2e8fa3_HPS_FORMAT_FIGEXP M_FIG C_FIG