Enteric Glial Cell Network Function is Required for Epithelial Barrier Restitution following Intestinal Ischemic Injury in the Early Postnatal Period

Ischemic damage to the intestinal epithelial barrier, such as in necrotizing enterocolitis or small intestinal volvulus, is associated with higher mortality rates in younger patients. We have recently reported a powerful pig model to investigate these age-dependent outcomes in which mucosal barrier restitution is strikingly absent in neonates but can be rescued by direct application of homogenized mucosa from older, juvenile pigs by a yet-undefined mechanism. Within the mucosa, a postnatally developing network of enteric glial cells (EGC) is gaining recognition as a key regulator of the mucosal barrier. Therefore, we hypothesized that the developing EGC network may play an important role in coordinating intestinal barrier repair in neonates. Neonatal and juvenile jejunal mucosa recovering from surgically induced intestinal ischemia was visualized by scanning electron microscopy and the transcriptomic phenotypes were assessed by bulk RNA sequencing. EGC network development was examined by gene set enrichment analysis, three-dimensional volume imaging and western blot and its function in regulating epithelial restitution assessed ex vivo in Ussing chamber using the glia-specific inhibitor fluoroacetate, and in vivo in co-culture assays. Here we refine and elaborate our translational model, confirming a neonatal phenotype characterized by a complete lack of coordinated reparative signaling in the mucosal microenvironment. Further, we report important evidence that the subepithelial EGC network changes significantly over the early postnatal period and demonstrate that EGC function in close proximity to wounded intestinal epithelium is critical to intestinal barrier restitution following ischemic injury. Comparative gene expression profiling analysis of RNA-seq data for homogenized mucosa of control and ischemia-injured jejunum of 2- and 6-week-old pigs.