UC San Diego

We propose that the teratoma, a recognized standard for validating pluripotency in stem cells, could be a promising platform for studying human developmental processes. Performing single cell RNA-seq of 179,632 cells across 23 teratomas from 4 cell lines, we found teratomas reproducibly contain approximately 20 cell types across all 3 germ layers, the inter-teratoma cell type heterogeneity was comparable to organoid systems, and that the teratoma gut and brain cell types correspond well to similar fetal cell types. Cellular barcoding confirmed that injected stem cells robustly engraft and contribute to all lineages. Using pooled CRISPR-Cas9 knockout screens, we showed that teratomas can simultaneously assay the effects of genetic perturbations across all germ layers. Additionally, we demonstrated teratomas can be enriched for specific lineages via a genetic or materials approach. We either molecularly sculpted via miRNA-regulated suicide gene expression or assayed teratomas under multiple matrix conditions. Taken together, the teratoma is a promising platform for modeling multi-lineage development, pan-tissue functional genetic screening, and tissue engineering.