Neonatal Enteric Glia Enhance Intestinal Epithelial Restitution in vitro Following Exposure to Sterile Colonic Luminal Content of Mature but not Neonatal Pigs

Abstract

Neonates exhibit significantly poorer outcomes from damage to the intestinal epithelium following ischemia for unknown reasons. In our pig model, we recently discovered an age-dependent epithelial restitution defect in ischemia-injured neonatal intestine that is rescued by application of homogenized juvenile mucosa, but the mechanism remains unknown. Enteric glial cells (EGC) have been shown to promote epithelial restitution following injury via paracrine signaling and are abundant in the intestinal mucosa of juvenile but not neonatal pigs. Co-culture studies have shown that pig EGC enhance restitution in epithelial monolayers following scratch wounding. In mice, postnatal maturation and maintenance of the EGC network is purportedly driven by colonization of gut microbiota. Furthermore, weaning of neonates leads to drastic shifts in the dynamics and populations of these gut microbiota. Therefore, we believe that changes to pig intestinal microbiota during weaning may play a key role in EGC maturation required for proper epithelial restitution. We hypothesized that treatment with mature (>6 weeks of age), but not neonatal (2 weeks of age), luminal content would improve restitution of neonatal epithelial monolayers co-cultured with neonatal EGC. We compared the effect of sterile-filtered neonatal or mature luminal content addition to the apical chamber on scratch wound restitution in neonatal porcine IPEC-J2 monolayers in monoculture or co-culture with primary porcine neonatal submucosal EGC using a transwell system (n = 9). Our results support a significant effect of luminal content treatment in the presence of EGC (P=0.0085). Specifically, mature luminal content treatment enhanced IPEC-J2 wound closure in co-culture with EGC but not in IPEC-J2 monoculture (P=0.0156). EGC co-culture alone or treated with neonatal lumen content did not affect restitution. Both neonatal and mature luminal content treatment decreased restitution in monoculture, but this effect was not significant. These data suggest that EGC provide secretory signals to the intestinal epithelium that promote repair in response to a component of mature luminal content, which we believe to be microbial products. Future work aims to determine what is driving these differences in restitution by analyzing neonatal and mature luminal secretomes. NIH 5 T35 OD 11070-12; NIH K01 OD 028207; NIH P30 DK 034987; NIH-NICHD R01 HD095876; USDA-NIFA VMCG-0065. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.