APC sets the Wnt tone necessary for cerebral cortical progenitor development

Area of Science:

• Neuroscience
• Developmental Biology
• Molecular Biology

Background:

• Adenomatous polyposis coli (APC) is a key regulator of β-catenin activity within the Wnt signaling pathway.
• The specific role of the APC-β-catenin pathway in the development of the cerebral cortex remains largely uncharacterized.
• Cerebral cortical formation relies on the precise regulation of progenitor cell development.

Purpose of the Study:

• To genetically investigate the distinct roles of APC-regulated β-catenin signaling in the development of cortical progenitor cells.
• To understand the necessity of this pathway for early-stage cerebral cortical formation.

Main Methods:

• Utilized genetic manipulation to specifically inactivate the APC-β-catenin pathway in radial progenitor cells.
• Analyzed the impact of APC deletion on β-catenin levels, Wnt signaling tone, Notch1 signaling, and primary cilium maintenance.
• Investigated the rescue effects of β-catenin deletion or inhibition in APC-null progenitors.

Main Results:

• Inactivation of the APC-β-catenin pathway in radial progenitors disrupts orderly differentiation and cerebral cortex formation.
• APC deletion leads to deregulated β-catenin, elevated Wnt signaling, and impaired Notch1 signaling and primary cilium maintenance.
• β-catenin deregulation affects cilium maintenance and Tulp3-mediated signaling, critical for intraflagellar transport.
• Restoration of normal β-catenin levels or activity rescues the developmental defects caused by APC loss.

Conclusions:

• Appropriate β-catenin-mediated Wnt signaling, regulated by APC, is essential for normal cerebral cortical development.
• APC-regulated β-catenin activity establishes the necessary Wnt signaling tone for proper radial progenitor function and differentiation.
• Disruption of this pathway highlights the critical role of precise Wnt signaling balance in neurodevelopment.