MADM tracing reveals altered timing and reduced neuron diversity in cortical organoids
Using MADM in mouse ESC-derived cortical organoids, researchers found radial glial progenitors display flexible proliferation and generate fewer neuron subtypes than in vivo.
MADM technology was introduced into mouse embryonic stem cells to monitor radial glial progenitor (RGP) behavior within cortical organoids. Single-cell RNA sequencing showed that organoid differentiation mirrors in vivo corticogenesis in cell-type composition and developmental timing. Nevertheless, clonal analysis revealed that organoid RGPs lack the linear, temporally stereotyped division pattern of in vivo RGPs, exhibiting greater proliferative plasticity and a pronounced shift toward lineage-restricted clones that produce fewer cortical projection neuron subtypes.
Small neurogenic clones, absent in vivo, appeared frequently, and differential gene expression suggested altered metabolic and signaling environments. Despite these differences, organoids still transitioned from neurogenesis to gliogenesis after similar timelines, underscoring the role of non-cell-autonomous niche signals for faithful temporal regulation of cortical progenitor lineages.
Why it matters
The findings indicate brain organoids may not fully replicate neuronal timing and diversity, affecting their reliability for disease studies.
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