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bioRxiv2025

Electrophysiological development and functional plasticity in dissociated human cerebral organoids across multiple cell lines

Microelectrode arrays (MEAs) are increasingly used to profile the development of synchronised activity in neural organoids, yet no organoid study has investigated the consistency of electrophysiological development across cell lines. Here, we used dissociated neural organoids derived from four cell lines on MEAs to characterise functional synapse development using multiple parameters across time. The dissociated organoids had increasing functional connectivity and network activity over time across all cell lines and plasticity in response to synaptic-like stimulation. Like the organoids they were derived from, dissociated organoid cultures contained a diverse mixture of cell types. Variability in activity parameters was associated with differences in cell type composition and regional identity, which in turn were affected by donor cell line and batch effects. These results demonstrate that dissociated cerebral organoids can generate functional neurons, akin to primary neuronal cultures from brain tissue, providing a scalable model for studies of neurodevelopment and synaptic function.

neuroscience↗

bioRxiv2024

Impact of intragenic NRXN1 deletions on early cortical development

BackgroundDeletions in NRXN1 are strongly associated with neurodevelopmental and psychiatric conditions. While exonic deletions are well-studied, intragenic deletions, particularly in intron 5, are less understood and generally consider benign. Recent studies show exonic deletions impact isoform diversity during neurodevelopment, affecting neurogenesis and neuronal function. However, whether intragenic deletions impact isoform expression and neurodevelopment remains underexplored. MethodsWe used hiPSCs from typically developing individuals (control) and those with NRXN1 intron 5 deletions to study neurodevelopment. HiPSCs were differentiated towards a cortical fate, with NRXN1 isoform expression, molecular differences, and neuronal morphology examined. ResultsWe observed distinct NRXN1 isoform expression dynamics during early neurodevelopment, with two expression peaks post-neuronal induction and NRXN1{beta} being most highly expressed. Both NRXN1 deletion and control lines showed similar acquisition of regional and cell fate identity, but significant differences in NRXN1 isoform expression were observed between deletion and control lines, and between deletion lines. RNA sequencing revealed genotype-dependent alterations, particularly in pathways related to synaptic function and neuronal morphology. Consistent with these findings, NRXN1 deletion lines exhibited altered dendrite outgrowth, with variations between deletion lines. ConclusionsOur results indicate a potential role for intron 5 in controlling NRXN1 isoform expression during neurodevelopment. Alterations in gene expression profiles, correlated with morphological changes, suggest a role for NRXN1 isoforms in shaping dendritic morphology. Molecular and cellular differences observed between lines with identical intronic deletions suggest that additional factors, such as genetic background or biological sex, may also play an important role in these phenotypes. Collectively, these findings indicate that NRXN1 intronic deletions are not benign, influencing isoform expression, cellular phenotypes, and neurodevelopment.

neuroscience↗