ESTABLISHMENT OF AN IN VITRO INTESTINAL INFLAMMATORY MODEL USING HUMAN INTESTINAL EPITHELIAL AND IMMUNE CELLS VIA THE TLR4/NF-κB SIGNALING PATHWAY

Abstract

Inflammatory bowel disease (IBD) is a chronic condition marked by persistent inflammation of the digestive tract, in which the interaction between intestinal epithelial and immune cells plays a pivotal role through key signaling pathways. To investigate the molecular mechanisms underlying intestinal inflammation, we examined the effects of lipopolysaccharide (LPS) on human intestinal epithelial (HIEC-6) and pro-monocytic (U937) cells to establish an in vitro model resembling IBD. Cells were treated with varying concentrations of LPS for different incubation periods, and molecular changes were assessed by RT-PCR and western blotting. In HIEC-6 cells, LPS markedly enhanced IL-6 and COX-2 gene expression and increased iNOS and TLR4 protein levels. In U937 cells, LPS strongly induced IL-6, IL-1β, TNF-α, and COX-2 transcripts and elevated the protein expression of TLR4, TNF-α, and IL-6. Furthermore, nuclear translocation of NF-κB was prominently detected in both cell types, confirming the activation of the TLR4/NF-κB signaling pathway. These findings demonstrate that LPS stimulation effectively reproduces hallmark features of intestinal inflammation, pro-inflammatory cytokine induction, and NF-κB activation. The established in vitro system provides a robust and reproducible platform for elucidating the molecular mechanisms of intestinal inflammation and for evaluating therapeutic interventions targeting TLR4/NF-κB signaling in IBD and related disorders.