The gastrointestinal (GI) tract plays a vital role in nutrient absorption and serves as a critical barrier against pathogens. Enteropathogenic Escherichia coli (EPEC), a significant cause of infantile diarrhoea in developing countries, disrupts this barrier, leading to severe illness. Pathogen access and adherence to the host epithelial cells is the first step in establishing successful infection. The GI tract possesses effective defence mechanisms to prevent pathogen colonisation and maintain tissue homeostasis. Immature GI epithelium in neonates born premature can lead to the onset of intestinal inflammation such as Necrotising enterocolitis (NEC). Traditional cell line models, like HeLa cells, have limitations in replicating the complexity of human intestinal tissue, prompting the need for more physiologically relevant models. Therefore, a more accurate model representing host-pathogen interaction in vivo is central to understanding the host innate immune factors regulating intestinal infections as well as inflammatory disease states. Here, to investigate mucosal innate immune system in EPEC infection as well as in NEC, a primary intestinal cell model using adult stem cell-derived organoids was established, ideal for a more detailed analysis of host-pathogen interaction as well as intestinal immune responses and barrier function in disease setting. Organoid-derived monolayers were generated from small intestine and colon that showed features of the native tissue including intestinal cell phenotypes. Using this technique, the findings reveal that the primary cells exhibit reduced bacterial adherence, greater cellular resilience, and a delayed but appropriate immune response compared to HeLa cells. This model enabled the identification of important mucosal factors in preventing infection, through the presence of goblet cells and mucus barrier. One mucus-associated protein, FCGBP was identified as a potential antimicrobial protein. Analysis of EPEC adherence in colonic monolayers as well as bacterial growth in cell supernatants highlighted the potential role of FCGBP, together with TFF3, in inhibiting EPEC colonisation. The identification of these factors broadens our understanding of mucosal defence with implications for future therapies. Finally, exploration of organoids generated from preterm and term neonate intestinal tissue revealed higher expression of pattern recognition receptors like TLR2 and TLR4 in preterm organoids. Despite this upregulation, an expected inflammatory response to receptor activation is absent in preterm models, indicating a potential disconnect between receptor expression and immune function. These insights shed light on the GI tract's innate immunity and solidify the importance and need for a more physiologically relevant model for studying host-pathogen interaction and inflammatory diseases like NEC.
Mastura Neyazi (Wed,) studied this question.