LHX8 is expressed early during MGE-derived interneuron production, and its expression is reduced in cortical interneurons (Flandin et al., 2011; Fragkouli et al., 2005; Fragkouli et al., 2009). Indeed, we observed that the nMGE clusters from earlier timepoints expressed LHX8, but there was little or no LHX8 expression at later timepoints, or in nCTX neurons (Figure 5D, Padj <0.001). There was a split between CORT− and CORT+ nCTX clusters that indicated the latter represented a more mature population. CORT− cells expressed more CXCR4 and NKX2-1, which are repressed as cortical interneurons mature. The CORT+ cells expressed higher levels of SST, GRIA4, and RBFOX3 (see Figure 4A, Padj <0.001 for all genes described, CORT− vs. CORT+ clusters). These gene expression trends indicate that differentiation and maturation of in vitro-derived interneurons and oligodendrocytes occurs side by side in vitro.
