Patient Brain Organoids Identify a Link between the 16p11.2 Copy Number Variant and the RBFOX1 Gene

Area of Science:

• Genetics
• Neuroscience
• Developmental Biology

Background:

• Copy number variants (CNVs) at the 16p11.2 genomic locus are strongly associated with neurodevelopmental disorders.
• The precise molecular mechanisms underlying these neurodevelopmental phenotypes remain largely unknown.
• Human cortical organoids (hCOs) offer a promising model to investigate human-specific disease mechanisms.

Purpose of the Study:

• To investigate the cellular and molecular consequences of 16p11.2 CNVs using human cortical organoids.
• To identify novel genes and pathways affected by 16p11.2 deletions.
• To explore potential convergent therapeutic strategies for neurodevelopmental disorders.

Main Methods:

• Generation of hCOs from 17 individuals with 16p11.2 CNVs and controls.
• Single-cell RNA-sequencing analysis of 167,958 cells.
• Validation of gene expression changes at mRNA and protein levels.

Main Results:

• Identification of neuronal-specific differential gene expression related to cell-cell adhesion and neuronal projection growth.
• Reduced RBFOX1 mRNA and protein levels in 16p11.2 deletion syndrome organoids.
• Perturbation of RBFOX1-regulated genes in patient-derived organoids, establishing a link between independent CNVs and neurodevelopmental phenotypes.

Conclusions:

• 16p11.2 CNVs disrupt critical neurodevelopmental pathways, including cell adhesion and neuronal growth.
• RBFOX1 is implicated in the pathogenesis of 16p11.2 deletion syndrome, connecting it to other neurodevelopmental conditions.
• Convergent signaling pathways suggest potential common therapeutic targets for diverse rare neurodevelopmental diseases.