Comparison of iPSC-derived human intestinal epithelial cells with Caco-2 cells and human in vivo data after exposure to Lactiplantibacillus plantarum WCFS1

To investigate intestinal health and its potential disruptors in vitro, representative models are required. Human induced pluripotent stem cell (hiPSC)-derived intestinal epithelial cells (IECs) more closely resemble the in vivo intestinal tissue than conventional in vitro models like human colonic adenocarcinoma Caco-2 cells. However, the potential of IECs to study immune-related responses upon external stimuli has not been investigated in detail yet. The aim of the current study was to evaluate immune-related effects of IECs by challenging them with a pro-inflammatory cytokine cocktail. Subsequently, the effects of Lactiplantibacillus plantarum WCFS1 were investigated in unchallenged and challenged IECs. All exposures were compared to Caco-2 cells and in vivo data where possible. Upon the inflammatory challenge, IECs and Caco-2 cells induced a pro-inflammatory response which was strongest in IECs. Heat-killed L. plantarum exerted the strongest effect on immune parameters in the IEC model, while L. plantarum in the stationary growth phase had most pronounced effects on immune-related gene expression in Caco-2 cells. Unfortunately, comparison to in vivo transcriptomics data showed limited similarities, which could be explained by essential differences in the study setups. Altogether, hiPSC-derived IECs show a high potential as a model to study immune-related responses in the intestinal epithelium in vitro. Overall design: To investigate the effects of L. plantarum on hiPSC-derived IECs and Caco-2 cell models, both cell models were exposed to heat-killed and stationary L. plantarum for 96 hours. After 24h of L. plantarum exposure, the pro-inflammatory stimulus was intitated (i.e., 2 ng/mL IFN-γ for 24 hours, followed by exposure to 1 ng/mL IL-1β and 10 ng/mL TNFα for another 48 hours). After exposure, RNAseq analysis was performed on three samples per experimental condition, i.e., healthy Caco-2 and IECs (unchallenged cells without L. plantarum (control) and exposed to stationary or heat-killed L. plantarum), and challenged Caco-2 and IECs (challenged cells without L. plantarum exposure (control) and exposed to stationary or heat-killed L. plantarum.