Abstract
Sensory neurons residing in dorsal root ganglia (DRG) transmit sensory information such as pain, itch, touch, pressure and bodily position to the central nervous system. The activity of sensory neurons is regulated by non-neuronal cell types in the DRG, including satellite glial cells (SGCs) and fibroblasts. Dysregulated gene expression in DRG cells contributes to sensory nervous system disorders such as chronic pain and itch. Understanding the genetic underpinnings of these conditions requires dissecting transcriptional regulation in human DRG (hDRG). In this study, we profiled transcriptomic and chromatin accessibility landscapes from postmortem hDRG samples at single-cell level. We demonstrate that sequencing depth significantly impacts downstream analysis, with deeper sequencing yielding more detected cells and features, improved data integration, refined clustering and annotation, and more accurate scientific interpretations. We identified nine major cell types, defined their molecular signatures, and mapped cis-regulatory landscapes. Integration of gene expression with chromatin accessibility enabled peak-gene association and transcriptional network analyses, revealing transcription factors, their target genes, and their regulatory elements. This approach uncovered cell types, genes, and cis-regulatory regions potentially driving pain conditions. Our unbiased genome-wide analysis confirmed known pain-related genes and highlighted novel candidates. These findings provide new insight into molecular mechanisms and candidate cell types involved in pain. Importantly, our results demonstrate that non-neuronal cell types, including endothelial cells, fibroblasts, macrophages, and SGCs, play critical roles in pain pathogenesis and should be investigated as therapeutic targets.