Cellular diversity of the developing chick trigeminal ganglion at single-cell resolution

Background: The trigeminal ganglion (TG) is a structure of the peripheral nervous system, composed of neuronal and non-neuronal cell types, that integrates sensory input from the face and jaw. The developing TG is derived from two embryonic cell populations: neural crest and cranial placode. Both populations play critical roles in TG development and must interact to coordinate changes in gene expression that regulate specification, differentiation, and organization. However, the molecular characteristics of the heterogeneous cell populations within the developing TG remain poorly defined. Results: We performed single-cell RNA-sequencing (scRNA-seq) on TG from developing chick embryos at HH17. Our high-resolution dataset (14 clusters, ~87000 cells) provides insight into cellular diversity within the developing TG. As expected, we identified placode-derived neurons as well as neural crest cells prior to neuronal differentiation. In addition to classic markers, we identified novel transcripts with unknown roles in TG development, including several long non-coding RNAs (lncRNAs). Conclusions: We generated a single-cell atlas of the developing chick trigeminal ganglion during early axonogenesis and defined the transcriptomic states of its diverse cell populations. Our results provide a useful resource for better understanding the cell populations contributing to TG development and gene expression that drives cell identity and differentiation. Overall design: Pooled left and right trigeminal ganglia (TG) samples were generated by microdissection of 20 TG from separate embryos (left and right ganglia were never collected from the same embryo). Two duplicate pooled left and right samples of 20 TG were collected in total and enzymatically dissociated to generate single cell suspensions that were then fixed and sequenced to generate single cell RNA seq data using Parse Evercode WT 100K v3 kit.