Presentation Type
Oral/Paper Presentation
Abstract
Necrotizing enterocolitis (NEC) primarily affects premature infants and is characterized by intestinal necrosis, inflammation, and high mortality. Toll-like receptor 4 (TLR4)-induced apoptosis of intestinal epithelial cells is thought to drive NEC development. Upon binding bacterial lipopolysaccharide (LPS), TLR4 signaling activates NF-κB, leading to inflammatory gene expression. Indole-3-carbinol (I3C), a pro-ligand of the aryl hydrocarbon receptor (AhR), prevents NEC in a mouse model by downregulating TLR4, despite reduced AhR expression in NEC-affected intestines. However, the molecular mechanism behind the reduced expression of AhR in NEC is unclear. To model NEC in vitro, we treated IEC-6 enterocytes with LPS, which reduces AhR expression. Next, we assessed I3C’s effect on cell viability following LPS treatment. I3C failed to reverse LPS-induced cytotoxicity, as measured by MTT assay. We then investigated how LPS reduces AhR expression, hypothesizing that this occurs via TLR4/NF-κB activation. IEC-6 cells were pretreated with the TLR4 inhibitor C34 before LPS exposure, but AhR expression remained unchanged, suggesting that TLR4 is not responsible for LPS-induced AhR downregulation. However, pretreatment with the NF-κB inhibitor JSH-23 abolished LPS-induced AhR suppression, indicating that NF-κB mediates this effect. These findings suggest that targeting NF-κB signaling may enhance the therapeutic potential of AhR ligands for NEC by restoring AhR expression in NEC tissues. Further elucidation of this mechanism could improve NEC treatment strategies.
Faculty Mentor
Dr. Kyle Brawner
Recommended Citation
Longoria, Gabriella, "Investigating the Potential Ability of the TLR4-NF-κB Axis to Reduce Aryl Hydrocarbon Receptor Expression in Intestinal Epithelial Cells" (2025). Student Scholar Symposium. 148.
https://digitalcollections.lipscomb.edu/student_scholars_symposium/2025/Full_schedule/148
Included in
Investigating the Potential Ability of the TLR4-NF-κB Axis to Reduce Aryl Hydrocarbon Receptor Expression in Intestinal Epithelial Cells
Necrotizing enterocolitis (NEC) primarily affects premature infants and is characterized by intestinal necrosis, inflammation, and high mortality. Toll-like receptor 4 (TLR4)-induced apoptosis of intestinal epithelial cells is thought to drive NEC development. Upon binding bacterial lipopolysaccharide (LPS), TLR4 signaling activates NF-κB, leading to inflammatory gene expression. Indole-3-carbinol (I3C), a pro-ligand of the aryl hydrocarbon receptor (AhR), prevents NEC in a mouse model by downregulating TLR4, despite reduced AhR expression in NEC-affected intestines. However, the molecular mechanism behind the reduced expression of AhR in NEC is unclear. To model NEC in vitro, we treated IEC-6 enterocytes with LPS, which reduces AhR expression. Next, we assessed I3C’s effect on cell viability following LPS treatment. I3C failed to reverse LPS-induced cytotoxicity, as measured by MTT assay. We then investigated how LPS reduces AhR expression, hypothesizing that this occurs via TLR4/NF-κB activation. IEC-6 cells were pretreated with the TLR4 inhibitor C34 before LPS exposure, but AhR expression remained unchanged, suggesting that TLR4 is not responsible for LPS-induced AhR downregulation. However, pretreatment with the NF-κB inhibitor JSH-23 abolished LPS-induced AhR suppression, indicating that NF-κB mediates this effect. These findings suggest that targeting NF-κB signaling may enhance the therapeutic potential of AhR ligands for NEC by restoring AhR expression in NEC tissues. Further elucidation of this mechanism could improve NEC treatment strategies.