Morpho-Functional Responsiveness of Caco-2 Enterocyte-like Monolayers to Insulin in a Pro-Inflammatory Environment

In exerting its actions on the utilization and storage of nutrients, the hormonal effects of insulin (INS) on target cells include important changes in terms of cell morphology involving cytoskeletal actin. Sensitivity to INS affects intestinal epithelial cells, which express receptors through which tight junctions and barrier permeability are also modulated. Nevertheless, the impact of INS on physiological rather than pathophysiological processes along gastrointestinal epithelia is not fully established. Here, we investigate INS effects on differentiated Caco-2 monolayers challenged by inflammatory stimuli, i.e., interleukin 1 beta (IL-1β) and interferon gamma (IFN-γ), aiming to identify morpho-functional variations potentially associated with INS-dependent responses in intestinal epithelia differentially driven by different inflammation mediators. By observing the actin cytoskeleton, we characterized the impact of INS on actin structures' organization, both in the absence and presence of pro-inflammatory treatments. Coherently, we observed altered expression of proteins interrelated to cytoskeletal dynamics (FAK, ITGB1), particularly evident in the synergistic action of IFN-γ and INS, also confirmed by the impact on INS-mediated regulation of the MAPK signalling pathway. Overall, the results describe a modular responsiveness of enterocyte-like monolayers to INS, depending on different inflammatory mediators, hinting at the interplay between INS signalling and morpho-functional remodelling in intestinal epithelial cells.