Glial Guidance Drives Postnatal Intestinal Reinnervation by Enteric Neurons
This study investigates the phenomenon of postnatal plasticity within the enteric nervous system (ENS), specifically investigating the reinnervation potential of post-mitotic enteric neurons. Employing BAF53b-Cre for selective tracing, the reinnervation capabilities of postnatal enteric neurons in multiple model systems are shown. Denervated enteric neurons exhibit the ability to regenerate neurites in vitro, with neurite complexity and direction notably influenced by contact with enteric glial cells (EGCs). In vivo nerve fibers from transplanted enteric neurons exclusively interface with EGCs. Resident EGCs are sustained after Cre dependent ablation of enteric neurons and govern the architecture of the ENS by reinnervating enteric neurons. Transplantation experiments underscore the swift reintegration and reinnervation potential of post-mitotic neurons, leading to restored muscle function within two weeks. Optogenetic investigations further delineate time-dependent functional recovery via transplantation of isolated enteric ganglia. These revelations demonstrate the structural and functional reinnervation capacity of post-mitotic enteric neurons, underscored by EGC guidance. Overall design: To ablate enteric neurons expressing inducible diphtheria toxin receptor (iDTR), BAF53b::iDTR mice were generated. Diphtheria toxin (Sigma Aldrich, St. Louise, MO, USA, #D0564) was prepared by dilution in PBS and India ink to a final dose of 0.33ng/µL of DT and 10% India ink at final volume.  Mice were anesthetized by isoflurane to perform laparotomy and delivery of 4µL of the DT solution by microinjection to the muscularis propria with the India ink used to confirm the injection site. Injection of the solution DT was performed in littermate mice lacking iDTR expression as experimental controls.