Harmonized cross-species cell atlases of trigeminal and dorsal root ganglia

Sensory neurons in the dorsal root ganglion (DRG) and trigeminal ganglion (TG) are specialized to detect and transduce diverse environmental stimuli to the central nervous system. Single-cell RNA-sequencing (scRNA-seq) has provided insights into the diversity of sensory ganglia cell types in rodents, non-human primates, and humans, but it remains difficult to compare cell types across studies and species. Here, we built harmonized atlases of the DRG and TG that describe 18 neuronal and 11 non-neuronal cell types across 6 species and 31 studies. We then demonstrate the utility of this harmonized atlas by using it to annotate DRG nuclei/cells from both human and the highly regenerative axolotl. We observe that the transcriptomes of sensory neuron subtypes are broadly similar across vertebrates, but the expression of functionally important neuropeptides and channels can vary notably. The resources presented here can guide future studies in comparative transcriptomics, simplify cell type nomenclature differences across studies, and help prioritize targets for future analgesic development.