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Updated: Jun 24, 2025
In Vitro Modeling of Down Syndrome Neurogenesis Using Human-Induced Pluripotent Stem Cells
Published on: March 7, 2025
A dynamic in vitro model of Down syndrome neurogenesis with trisomy 21 gene dosage correction
Prakhar Bansal1,2, Erin C Banda2, Heather R Glatt-Deeley2
1Graduate Program in Genetics and Developmental Biology, UCONN Health, University of Connecticut, Farmington, CT, USA.
Abstract:
Excess gene dosage from chromosome 21 (chr21) causes Down syndrome (DS), spanning developmental and acute phenotypes in terminal cell types. Which phenotypes remain amenable to intervention after development is unknown. To address this question in a model of DS neurogenesis, we derived trisomy 21 (T21) human induced pluripotent stem cells (iPSCs) alongside, otherwise, isogenic euploid controls from mosaic DS fibroblasts and equipped one chr21 copy with an inducible XIST transgene. Monoallelic chr21 silencing by XIST is near-complete and irreversible in iPSCs. Differential expression reveals that T21 neural lineages and iPSCs share suppressed translation and mitochondrial pathways and activate cellular stress responses. When XIST is induced before the neural progenitor stage, T21 dosage correction suppresses a pronounced skew toward astrogenesis in neural differentiation. Because our transgene remains inducible in postmitotic T21 neurons and astrocytes, we demonstrate that XIST efficiently represses genes even after terminal differentiation, which will empower exploration of cell type-specific T21 phenotypes that remain responsive to chr21 dosage.
Insights
This study shows that chromosome 21 (chr21) gene dosage correction in Down syndrome (DS) models can reverse neurogenesis defects. Inducible XIST enables chr21 gene silencing even in differentiated cells, opening therapeutic avenues.
Area of Science:
- Genetics
- Developmental Biology
- Stem Cell Biology
Background:
- Down syndrome (DS) is caused by trisomy of chromosome 21 (chr21), leading to developmental and acute phenotypes.
- The potential for therapeutic intervention in DS phenotypes after development remains largely unexplored.
- Understanding chr21 gene dosage effects in neural development is crucial for identifying therapeutic targets.
Purpose of the Study:
- To investigate the impact of chr21 gene dosage on neurogenesis in a human Down syndrome model.
- To determine if chr21 gene silencing can correct developmental phenotypes in neural cells.
- To assess the efficacy of inducible XIST-mediated chr21 silencing in both developing and terminally differentiated cells.
Main Methods:
- Generation of trisomy 21 (T21) human induced pluripotent stem cells (iPSCs) from mosaic DS fibroblasts with isogenic euploid controls.
- Introduction of an inducible XIST transgene into one chr21 copy for monoallelic gene silencing.
- Neural differentiation of T21 iPSCs and analysis of gene expression, cellular pathways, and differentiation trajectories.
- Assessment of XIST-induced gene repression in postmitotic neurons and astrocytes.
Main Results:
- T21 neural lineages and iPSCs exhibit suppressed translation, mitochondrial pathway alterations, and activated stress responses.
- Induction of XIST before neural progenitor stage corrected a T21-associated skew towards astrogenesis.
- XIST efficiently repressed chr21 genes even in postmitotic T21 neurons and astrocytes, demonstrating its efficacy in terminally differentiated cells.
Conclusions:
- chr21 gene dosage correction via inducible XIST can reverse specific neurodevelopmental phenotypes in Down syndrome models.
- XIST-mediated gene silencing is effective even in terminally differentiated neural cells, offering a potential therapeutic strategy for DS.
- This approach enables the study of cell type-specific T21 phenotypes that remain responsive to chr21 dosage modulation.
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