Migration pathways of sacral neural crest during development of lower urogenital tract innervation

The migration and fate of cranial and vagal neural crest-derived progenitor cells (NCPCs) have been extensively studied; however, much less is known about sacral NCPCs particularly in regard to their distribution in the urogenital system. To construct a spatiotemporal map of NCPC migration pathways into the developing lower urinary tract, we utilized the Sox10-H2BVenus transgene to visualize NCPCs expressing Sox10. Our aim was to define the relationship of Sox10-expressing NCPCs relative to bladder innervation, smooth muscle differentiation, and vascularization through fetal development into adulthood. Sacral NCPC migration is a highly regimented, specifically timed process, with several potential regulatory mileposts. Neuronal differentiation occurs concomitantly with sacral NCPC migration, and neuronal cell bodies are present even before the pelvic ganglia coalesce. Sacral NCPCs reside within the pelvic ganglia anlagen through 13.5 days post coitum (dpc), after which they begin streaming into the bladder body in progressive waves. Smooth muscle differentiation and vascularization of the bladder initiate prior to innervation and appear to be independent processes. In adult bladder, the majority of Sox10+ cells express the glial marker S100β, consistent with Sox10 being a glial marker in other tissues. However, rare Sox10+ NCPCs are seen in close proximity to blood vessels and not all are S100β+, suggesting either glial heterogeneity or a potential nonglial role for Sox10+ cells along vasculature. Taken together, the developmental atlas of Sox10+ NCPC migration and distribution profile of these cells in adult bladder provided here will serve as a roadmap for future investigation in mouse models of lower urinary tract dysfunction.