B. D. Bauman1, J. Meng1, S. Banerjee1, S. Roy1, W. Kennedy3, B. J. Segura1,2 2University of Minnesota,Pediatric Surgery,Minneapolis, MINNESOTA, USA 3University Of Minnesota,Neurology,Minneapolis, MINNESOTA, USA 1University Of Minnesota,General Surgery,Minneapolis, MINNESOTA, USA
Introduction:
Our studies presently underway are aimed at better understanding the underlying risks of pediatric intestinal disorders including inflammatory bowel disease and necrotizing enterocolitis (NEC) in premature infants. Our central hypothesis is that the relative prematurity of patients with NEC puts at them at greater risk of intestinal inflammation due to the underdeveloped nature of their enteric nervous system. Evidence from our lab and others suggests enteroglia may play a significant role in modulating intestinal inflammatory disorders through the maintenance of gut barrier function. Specifically, we have found that sphingosine-1-phosphate (S1P), a bioactive lipid, and FTY720, a known S1P agonist, mitigates intestinal inflmmation. To more fully understand the link between enteric glia, bioactive lipid signaling and NEC, we are now extending our studies into models of pediatric disease.
Methods:
Using in-vivo approaches involving DSS induced colitis in the mouse model, and in-vitro approaches involving the study of rat intestinal epithelial IEC-6 cells we investigated the putative signaling properties of the bioactive lipid sphingosine-1-phosphate (S1P)–known to cause calcium signaling in enteric glia, which bear its receptors based on our prior studies.
Results:
The S1P analog FTY720 (0.3 mg/kg daily by oral gavage) markedly attenuated the inflammatory response induced by 3.5% dextran sodium sulfate (DSS) by H&E analysis compared with controls in a mouse model of colitis at 3 and 5 days. Cultured rat intestinal epithelial cells (IECs) demonstrated enhanced tight junction formation (Occludin staining and transepithelial resistance) in response to enteric glial cell (EGC)-cultured media within 48 hours. By flow cytometry, Rat EGCs display traditional markers and the Toll like receptor 4 (TLR4). By QPCR, Rat EGCs show diminished expression of TLR4, TNFa, IL-1b, and iNOS response to S1P (1uM) treatment.
Conclusion:
Our data suggest that the sphingolipid analog FTY720 and S1P have effects upon inflammation in-vivo and in-vitro, respectively. This suggests that sphingolipids may modulate intestinal inflammation through a mechanism involving the enteric nervous system, potentially serving as a mode of preventive therapy in adults and children alike
