Figure 1.

Activation of WNT/CTNNB1 Signaling in Human MGE Progenitors

(A) Schematic of the procedure for generating dorsal and ventral telencephalic progenitors and neurons from hPSCs. Without ectopic morphogens, NEs were targeted to a cortical fate from days 10 to 17. For ventralization, a combination of SHH (250 ng/mL) and smoothened activator purmorphamine (0.3 μM) was added to the NE from days 10 to 17. Cortical progenitors generated glutamatergic neurons, whereas MGE progenitors produced cholinergic and GABAergic neurons.

(B) In the control (Ctrl) group, cortical progenitors expressed PAX6 but not NKX2.1 at day 17 after differentiation, whereas SHH-specified MGE progenitors only showed NKX2.1 expression. Scale bar, 50 μm.

(C) Canonical WNT signaling reporter hESCs were constructed through 7TGC lentivirus infection. Without WNT activation (DMSO), NEs derived from 7TGC-hESCs displayed no GFP fluorescence signal at day 8. Treatment with CHIR99021, a WNT activator, for 2 days significantly induced reporter GFP expression. Expression of mCherry marked lentivirus infection efficiency. Scale bar, 500 μm.

(D) MGE progenitors specified via SHH treatment in 7TGC-NEs displayed robust GFP signals as early as day 12 and persisted thereafter. Scale bar, 250 μm.

(E and F) mRNA expression of WNT ligands (E) and receptors (F) were evaluated in day 10-NEs and day 25-MGE progenitors. At least three independent experiments were performed; unpaired t test, ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001.