Analysis of genotype effects and inter-individual variability in iPSC-derived trisomy 21 neural progenitor cells.

Trisomy of human chromosome 21 (T21) gives rise to Down syndrome (DS), the most frequent live-born autosomal aneuploidy. T21 triggers genome-wide transcriptomic alterations that result in multiple atypical phenotypes with highly variable penetrance and expressivity in individuals with DS. Many of these phenotypes, including atypical neurodevelopment, emerge prenatally. To enable in vitro analyses of the cellular and molecular mechanisms leading to the neurological alterations associated with T21, we created and characterized a panel of genomically diverse T21 and euploid induced pluripotent stem cells (iPSCs). We subsequently differentiated these iPSCs to generate a panel of neural progenitor cells (NPCs). Alongside characterizing genotype effects from T21, we found that T21 NPCs showed inter-individual variability in growth rates, oxidative stress, senescence characteristics, and gene and protein expression. Pathway enrichment analyses of T21 NPCs identified vesicular transport, DNA repair, and cellular response to stress pathways. These results demonstrate T21-associated variability at the cellular level and suggest that cell lines from individuals with DS should not solely be analyzed as a homogenous population. Examining large cohorts of genetically diverse samples may more fully reveal the effects of aneuploidy on transcriptomic and phenotypic characteristics in T21 cell types. A panel of genomically diverse T21 and euploid induced pluripotent stem cells (iPSCs) were created and subsequently differentiated into neural progenitor cells (NPCs). T21 NPCs showed reduced growth, increased oxidative stress, and inter-individual variability in gene and protein expression. This inter-individual variability suggests that studies with large cohorts of genetically diverse T21 samples may more fully reveal the effects of aneuploidy.