Transcriptomic Analysis of Kidney-Innervating Spinal and Vagal Sensory Neurons

Afferent innervation of the kidney has been primarily associated with spinal afferents originating in dorsal root ganglia (DRG) between spinal levels T6-L2. These renal afferents were thought to preferentially innervate the renal pelvis, however, recent findings have identified renal afferents near glomeruli in the renal cortex. While renal afferents in the renal pelvis are known to either be chemosensitive or mechanosensitive, the physiological role of renal afferents innervating the renal cortex is unclear. Afferent tracing studies in the kidney have led to mixed abilities to selectively identify and isolate renal afferent cell bodies in DRG, and identify their functional roles. Here we used single cell RNA sequencing (scRNAseq) through Parse Biosciences to identify renal afferent neurons via the expression of neuronal injury markers after axotomy by unilateral nephrectomy. We hypothesized that sensory neurons innervating the kidney will express the neuronal injury marker Atf3 24 hours after nephrectomy of the right kidney, allowing for the identification of kidney-innervating afferent neurons based on comparing the left intact T6-L2 DRG and right axotomized DRG neurons. We additionally investigated vagal innervation of the kidney by including the left and right nodose ganglia (NG). scRNAseq data processing was completed in R using packages singleCellTK for quality control, Seurat for data visualization and analyses, and SingleR for cell type reference annotation. After quality control cell filtering steps, we annotated 7,411 cells into known DRG subtypes and Phox2b+ nodose neurons. Using Atf3 and Jun as neuronal injury markers, preliminary analyses identified clusters that highly expressed Atf3 in right axotomized DRG cell populations NF1/2, NP1, PEP2, and TH compared to left intact DRG neurons, and right nodose neurons (NG3-18). These clusters represent thinly myelinated Aδ low-threshold mechanoreceptors (LTMRs, NF1/2), Aδ peptidergic neurons (PEP2), unmyelinated C-LTMRs (TH), and non-peptidergic neurons (NP1). These cell types agree with prior renal afferent tracing and electrophysiology studies. Further gene expression analyses in these clusters will be completed after additional cell type annotation validation to identify more information about the potential modalities of these cells and how this information aligns with renal afferent physiological responses in the literature. This study aimed to preferentially identify kidney-innervating sensory neurons in DRG and NG with the goal of identifying genes that can be used to selectively label renal afferents. The gained ability to label these kidney-innervating neurons will provide the opportunity to investigate the physiological role and anatomy of these neurons in the kidney as well as transcriptional changes under pathophysiological conditions. Innovative Science Accelerator Program (ISAC) Award 23AU4374 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.