Clinically relevant cell culture model of inflammatory bowel diseases for identification of new therapeutic approaches.

Inflammatory Bowel Diseases (IDB) are chronic disorders characterized by gut inflammation, mucosal damage, increased epithelial permeability and altered mucus layer. No accurate in vitro model exists to simulate these characteristics. In this context, drug development for IBD or intestinal inflammation requires in vivo evaluations to verify treatments efficacy. A new model with altered mucus layer composition; altered epithelial permeability and pro-inflammatory crosstalk between immune and epithelial cells will be developed to enhance in vitro models for studying IBD treatments. The effects of dextran sulfate sodium and/or lipopolysaccharides on intestinal permeability, cytokines synthesis (IL-6, IL-8, TNF-α and IL-1β), mucins (MUC2, MUC5AC) and tight junction proteins expression (Claudin-1, ZO-1 and Occludin) were investigated in a tri-coculture model combining differentiated Caco-2/HT29-MTX cells and THP-1 cells. Two anti-inflammatory agents were evaluated to assess the model's therapeutic strategy applicability (corticoids and pro-resolving factors). Two in vitro models have been developed. The first model, characterized by increased permeability of the epithelial layer and subsequent secretion of inflammatory cytokines, can reproduce the different phases of inflammation, and enables the evaluation of preventive treatments. The second model simulates the acute phase of inflammation and allows for the assessment of curative treatments. Both models demonstrated reversibility when treated with betamethasone and pro-resolving factors. These in vitro models are valuable for selecting therapeutic agents prior to their application in in vivo models. They enable the assessment of agents' anti-inflammatory effects and their ability to permeate the inflamed epithelial layer and interact with immune cells.