POU3F2 regulates canonical Wnt signaling via SOX13 and ADNP to expand the neural progenitor population [RNAseq_LWnt3aNPCs]
Loss-of-function mutations in the transcription factor POU3F2 have been identified in individuals with neurodevelopmental disorders. To elucidate the mechanistic role of POU3F2 in human neurodevelopment, we induced POU3F2 disruption in human neural progenitor cells (NPCs). Mutation of POU3F2 in NPCs causes reduced baseline canonical Wnt signaling and decreased proliferation, resulting in premature specification of radial glia. Additionally, POU3F2 levels across genetically diverse NPCs significantly associate positively with baseline canonical Wnt signaling and negatively with markers of radial glia specification. Through a series of unbiased analyses, we show that SOX13 and ADNP are transcriptional targets of POU3F2 which mediate POU3F2's effects on Wnt signaling in human NPCs. Finally, we describe five individuals with autism spectrum disorder that harbor loss-of-function mutations in POU3F2, enhancing the genetic evidence for its critical role in human neurodevelopment. Together, these studies define POU3F2 as an activator of canonical Wnt signaling and mechanistically link two high-confidence autism genes, ADNP and POU3F2, in the regulation of neurodevelopment. Overall design: CRISPR/Cas9-edited and respective control iPSC lines were differentiated into neural progenitor cells (NPCs) using a dual-SMAD inhibition protocol adapted from Topol, et al. (2015). POU3F2 WT and MUT NPCs were treated with L or Wnt3a conditioned media for 24 hours and subjected to RNA-sequencing. This data is presented in Figure 2E-J.