Researchers have advanced autism research through two distinct approaches: identifying shared molecular patterns in mice and transplanting human brain tissue into mice. A study led by Eunjoon Kim grouped genetically diverse autism mouse models into two opposing patterns of brain gene activity, which were also reflected in human data. Separately, Stanford University scientists successfully integrated human brain organoids into living mice, creating a novel model to study human-specific brain development and test therapies for autism and epilepsy directly.
Autism gene convergence patterns
- ▪The Institute for Basic Science researchers identified two subgroups with opposing patterns of synaptic gene activity in prefrontal cortex transcriptomic data from 40 autistic individuals.
- ▪A study led by Eunjoon Kim at the Institute for Basic Science analyzed over 1,000 mouse brain transcriptomes to investigate whether diverse autism-risk genes converge on shared biological mechanisms.
- ▪The Institute for Basic Science study published in Science found that genetically distinct autism mouse models converge into two opposing patterns of brain gene activity.
Mouse model molecular groupings and human brain organoid transplantation
- ▪The Stanford University model allows researchers to study human-specific brain development features and test potential treatments for autism and epilepsy in a living organism.
- ▪Stanford University researchers developed a model by transplanting human skin-cell-derived brain organoids into genetically modified mice that lacked most of their own cerebral cortex.
- ▪The transplanted human brain cells in the Stanford University study integrated into the mouse neural networks and received blood supply without altering the mice's intelligence or behavior.
- ▪In the Institute for Basic Science study, Group 1 mice showed reduced expression of synaptic communication genes, while Group 2 mice displayed increased expression of those genes.
- ▪The Institute for Basic Science study grouped 17 genetically engineered mouse lines with autism-risk mutations into two broad molecular groups based on prefrontal cortex RNA-sequencing data.
Sex-dependent molecular differences
- ▪The context-dependent molecular groupings in the Institute for Basic Science study suggest that sex influences the molecular effects of specific autism-risk mutations.
- ▪The Institute for Basic Science researchers found that male and female mice carrying the same autism-risk mutation fell into different molecular groups in seven of the 17 lines.
Developmental stage molecular shifts
- ▪The two-group molecular distinction in the Institute for Basic Science study was much less pronounced in the hippocampus than in the prefrontal cortex.
- ▪The Institute for Basic Science study found that some mouse lines switched their molecular group assignments when examined at later developmental stages.
Fluoxetine drug response patterns
- ▪In the Institute for Basic Science study, early postnatal exposure to fluoxetine shifted gene expression patterns more consistently toward control levels in Group 1 mice than in Group 2.
- ▪The variable responses of Group 2 mice to fluoxetine in the Institute for Basic Science study differed depending on the specific gene set and cell type examined.
Lithium drug response patterns
- ▪In the Institute for Basic Science study, early postnatal exposure to fluoxetine shifted gene expression patterns more consistently toward control levels in Group 1 mice than in Group 2.
- ▪The Institute for Basic Science researchers noted that neither fluoxetine nor lithium reversed the observed differences in the relative proportions of brain-cell populations.
Debatable claims
- ▪Mouse models cannot reliably predict how autism treatments will work in humans
- ▪Stanford's human-mouse brain transplant model is ethically acceptable
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