Developmental programming and lineage branching of early human telencephalon

Area of Science:

• Neuroscience
• Developmental Biology
• Genetics

Background:

• The human telencephalon harbors diverse neuronal subtypes, including glutamatergic, GABAergic, and cholinergic neurons.
• The precise developmental mechanisms generating these neuronal subtypes in early human development remain largely unelucidated.

Purpose of the Study:

• To delineate the developmental roadmap of human telencephalic neurons.
• To identify key molecular players and progenitor cell dynamics during human neurogenesis.

Main Methods:

• Single-cell RNA sequencing (scRNA-seq) was employed to analyze cell populations.
• Stringent validation methods were used to confirm findings.

Main Results:

• A conserved developmental scheme involving radial glial cells (RGs), dividing intermediate progenitor cells (IPCs_div), and early postmitotic neuroblasts (eNBs) was identified for both dorsal and ventral telencephalon.
• The transcription factor ASCL1 was found to be critical for the transition from RGs to IPCs_div.
• Regionalized RGs exhibit heterogeneous differentiation potentials, predisposing them to specific neuronal fates.
• IPCs_div progressively exit the cell cycle, generating distinct neuronal subtypes through sister eNBs.

Conclusions:

• A general RGs-IPCs_div-eNBs developmental pathway governs human telencephalic progenitor differentiation.
• Neuronal fate determination is initiated during early dorsoventral regionalization, with subsequent refinement during neurogenesis and circuit integration.