Abstract
Polymorphonuclear neutrophils (PMN) respond to inflammation and infection in the gut. The physical and molecular interactions between the human intestinal epithelium and PMN in the gut mucosa and their coordinated responses to enteric pathogens, are poorly understood. We have established a PMN-enteroid co-culture model consisting of human intestinal stem-cell derived enteroid monolayers and peripheral blood PMN. The model was characterized in terms of tissue structure, barrier function, cell phenotype, production of cytokines, and innate immune responses. Shigella was used as a model enteric pathogen to interrogate PMN and epithelial cell interactions and innate immunity. PMN added to the enteroid monolayers increased production of IL-8 and rapidly transmigrated across the epithelial cell layer. PMN immune phenotype was distinctly modified in the gut microenvironment via molecular signals and direct epithelial cell contact. Apical exposure to Shigella increased PMN migration and production of IL-6 by co-cultured cells. PMN became activated and efficiently phagocytosed bacteria at the apical epithelial cell surface. The co-culture model revealed PMN-epithelial cell direct communication, tissue-driven PMN phenotypic adaptation and enhancement of anti-microbial function. This novel ex vivo epithelial cell-PMN co-culture system is relevant for mechanistic interrogation of host-microbe interactions and innate immune responses and the evaluation of preventive/therapeutic tools.
Competing Interest Statement
The authors have declared no competing interest.