Mapping the human DRG and spinal cord functional genome at cellular and spatial resolution

There are clear differences between mouse and human nociceptors that have profound implications for the development of pain therapeutics that target the peripheral nervous system. Our spatial sequencing experiments reveal a distinct set of cell types in the human dorsal root ganglion (DRG). In this research project, we will compare DRG tissues from organ donors and surgical patients with chronic pain. We will include a range of ages across the adult life-span in both men and women in an ethnically diverse population. In addition to the DRG, we will also examine the spinal cord. We have already conducted SPLiT-seq and spatial transcriptomic analysis of dorsal and ventral horn from a select number of organ donors demonstrating the viability of both techniques. Our data shows that like the DRG, there are clear species differences in the spinal cord highlighting the importance of this discovery work. In our first aim we will use spatial sequencing and SPLiT-seq technologies to precisely define the cell types of the human DRG. We will use organ donor and pain patient DRGs to define how cellular transcriptomes change with pain, and if the changes covary with sex and age. SN ATAC-seq will identify transcriptional states and regulatory elements in human DRG. In our second aim we will use the same technologies to map the cell types of the human dorsal horn. We will strive to use the combined DRG and spinal cord data to understand how DRG neuron subtypes are likely to connect to subsets of dorsal horn neurons. We will fully characterize the human neurons that comprise the spino-thalamic tract. Finally, in our third aim we will use ribosome profiling on human DRG and spinal cord to gain new insight into translational events in these tissues. Long-read sequencing will be used to map RNA modifications and splicing in a set of mRNAs that are critical for pain. Our work will create a comprehensive atlas of the transcriptome, epi-transcriptome, and translatome of neurons that comprise the first synapses in the pain pathway, including in chronic pain conditions.