Single-cell long-read sequencing in human cerebral organoids uncovers cell-type-specific and autism-associated exons

Dysregulation of alternative splicing has been repeatedly associated with neurodevelopmental disorders, but the extent of cell-type-specific splicing in human neural development remains largely uncharted. Here, single-cell long-read sequencing in induced pluripotent stem cell (iPSC)-derived cerebral organoids identifies over 31,000 uncatalogued isoforms and 4,531 cell-type-specific splicing events. Long reads un-cover coordinated splicing and cell-type-specific intron retention events, which are challenging to study with short reads. Retained neuronal introns are enriched in RNA splicing regulators, showing shorter lengths, higher GC contents, and weaker 50 splice sites. We use this dataset to explore the biological pro-cesses underlying neurological disorders, focusing on autism. In comparison with prior transcriptomic data, we find that the splicing program in autistic brains is closer to the progenitor state than differentiated neurons. Furthermore, cell-type-specific exons harbor significantly more de novo mutations in autism pro -bands than in siblings. Overall, these results highlight the importance of cell-type-specific splicing in autism and neuronal gene regulation.

Automated summary

This study used single-cell long-read sequencing to identify a large number of cell-type-specific splicing events and uncatalogued isoforms in human neural development. Retained neuronal introns were found to be enriched in RNA splicing regulators and had shorter lengths, higher GC contents, and weaker 50 splice sites. Cell-type-specific exons in autism pro-bands were found to have significantly more de novo mutations. These findings highlight the importance of cell-type-specific splicing in autism and neuronal gene regulation.