Caucasian neonates with IL-6 (rs1800795) were over 6 times more likely to have NEC (p = 0.013; OR = 6.61, 95% CI 1.48-29.39), and over 7 times more likely to have Stage III disease (p = 0.011; OR = 7.13, (95% CI 1.56-32.52).
These findings identify a novel link between TLR4-induced ER stress and ISC apoptosis in NEC pathogenesis and suggest that increased ER stress within the premature bowel predisposes to NEC development.
XBP1 splicing, ER stress and the UPR in NEC are associated with increased IL6 and IL8 expression levels, altered T cell differentiation and severe epithelial injury.
After exposure to probiotic conditioned media (PCM), immature human enterocytes, immature human intestinal xenografts, and primary enterocyte cultures of NEC tissue (NEC-IEC) were assayed for an IL-8 and IL-6 response to inflammatory stimuli.
Our lead compound, C34, is a 2-acetamidopyranoside (MW 389) with the formula C17H27NO9, which inhibited TLR4 in enterocytes and macrophages in vitro, and reduced systemic inflammation in mouse models of endotoxemia and necrotizing enterocolitis.
After exposure to probiotic conditioned media (PCM), immature human enterocytes, immature human intestinal xenografts, and primary enterocyte cultures of NEC tissue (NEC-IEC) were assayed for an IL-8 and IL-6 response to inflammatory stimuli.
These findings depart from current dogma in the field by identifying a unique effect of TLR4-induced autophagy within the intestinal epithelium in the pathogenesis of NEC and identify that the negative consequences of autophagy on enterocyte migration play an essential role in its development.
XBP1 splicing, ER stress and the UPR in NEC are associated with increased IL6 and IL8 expression levels, altered T cell differentiation and severe epithelial injury.
TLR4(-/-) mice and mice with enterocyte-specific deletion of TLR4 were protected from NEC; epithelial differentiation into goblet cells was increased via suppressed Notch signaling in the small intestinal epithelium.
In severe NEC, low hBD2 expression was accompanied by low TLR4/MD2 expression, suggesting an inadequate response to luminal bacteria, possibly predisposing those infants to the development of NEC.
Our findings suggest that TNF-alpha induces significant mitochondrial dysfunction and activation of mitochondrial apoptotic responses, leading to intestinal epithelial cell apoptosis during NEC.
Enterocyte proliferation was detected in IEC-6 cells or in ileum or colon from wild-type, TLR4-mutant, or TLR4(-/-) mice after induction of NEC or endotoxemia. beta-Catenin signaling was assessed by cell fractionation or immunoconfocal microscopy to detect its nuclear translocation.
We now hypothesize that activation of NOD2 in the newborn intestine inhibits TLR4, and that failure of NOD2 signaling leads to NEC through increased TLR4-mediated enterocyte apoptosis.
We now demonstrate that murine and human NEC are associated with increased intestinal HMGB1 expression, that serum HMGB1 is increased in murine NEC, and that HMGB1 inhibits enterocyte migration in vitro and in vivo in a TLR4-dependent manner.
Our findings provide evidence for a mechanism by which PAF augments inflammation in the intestinal epithelium through abnormal TLR4 upregulation, thereby contributing to the intestinal injury of NEC.
Thus, the reciprocal nature of TLR4 and TLR9 signaling within the neonatal intestine plays a role in the development of NEC and provides novel therapeutic approaches to this disease.
IL-6-174 genotypes were not associated with CLD and/or NEC, but the CC genotype was correlated with septicemia in both univariate and multivariate analyses (P = .027).