Tachykinin signaling defines distinct populations of glia in the enteric nervous system [Bulk RNA-seq]
One of the largest populations of glia outside the brain is in the gut. These enteric glia are involved in many functions from intestinal peristalsis to immunity, yet it is unclear if there are defined types with distinct roles in homeostasis. Comparing glia from divergent microenvironments in the mouse intestine, we found that mucosal glia resembled microglia and macrophages, while muscularis glia resembled satellite glia. Tacr3, encoding the receptor for neuropeptide Neurokinin B (NKB), was enriched within muscularis glia associated with neuronal soma and was undetectable in extraintestinal glia. Genetic or pharmacological manipulation of NKB-TACR3 signaling disrupted establishment of enteric glial populations during postnatal development, and dynamically modulated intestinal motor behaviors in adult mice. Collectively, we delineate spatially, transcriptionally and functionally distinct populations of enteric glia, identify one as an unanticipated target of TACR3 antagonists in clinical use, and establish this pathway as necessary for enteric glial diversification and function. Overall design: To determine how muscularis and mucosal enteric glia might differ in their transcriptional and functional properties,  GFP+ and GFP- cells from mucosa and muscle from the distal small intestine (ileum) of male and female 8–12-week-old Plp1eGFP mice were sorted for bulk RNA-sequencing. We then performed gene expression profiling analysis of four different sample types: GFP+ mucosal, GFP+ muscularis glia, GFP- mucosal cells, GFP- muscularis cells