PROJECT SUMMARY (Project 1) The lack of translation between mouse and human pain treatments has highlighted limitations of both the animal models of pain and molecular tools used to characterize them. This has prompted major efforts to characterize molecular features that are expressed in human nociceptors which may provide new ideas for pain therapeutic design. Recent advances in single-cell genomics now make it possible to characterize gene expression profiles, location in space, and the physiology of individual cells within complex tissues at unprecedented resolution. We have thus developed protocols for characterizing these multi-dimensional features of human nociceptors at single-cell resolution and propose to build upon these protocols here and in coordination with other U19 PRECISION Human Pain Centers. Molecular We then propose to leverage our single-cell genomic and epigenomic protocols to build a human nociceptor cell atlas derived from a diverse group of donor samples. These data will help characterize the diversity of human nociceptor subtypes, the epigenomic elements that establish these subtypes, and the effect of common genetic variation on gene expression within these clinically important cell types. Together, these datasets will provide a rich resource for mining novel pain therapeutic targets and for interpreting how common genetic variation affects gene expression in human nociceptors. This latter point is especially important for interpreting case-control studies across the pain research community. Structural We will generate and analyze large-scale single-cell spatial transcriptomic data of human ganglia to study the location of nociceptor subtypes in sensory ganglia and whether there are unique gene expression profiles in the non-neuronal cells (e.g. satellite glia) that are closely associated nociceptors as compared to other neuronal subtypes. Physiological We will culture fresh sensory neurons from each donor and measure their spontaneous and capsaicin-evoked activity. We will then use single-cell spatial transcriptomics to correlate gene expression profiles in each neuron with their associated spontaneous and capsaicin-evoked activity. These data will generate a resource that integrates both molecular and functional dimensions nociceptors.