Fructo-Oligosaccharides Enhance the Expression of Genes Related to Focal Adhesion- and Inflammation-Pathways in Small Intestinal Absorptive Caco-2 Cells.

Recently, we demonstrated, using mRNA microarray analysis, that fructo-oligosaccharides (FOS), which are indigestible carbohydrates, enhanced the expression of several inflammation-related genes, such as CLEC7A, CCL2, ITGA2, and F3, by ≥4-fold in Caco-2 cells, a model of human intestinal absorptive cells, independently of intestinal bacteria (Harasawa A et al., Nutrition, 112140, 2023). However, whether FOS enhances the expression of genes in other pathways, particularly the non-inflammatory pathways, in Caco-2 cells has not been investigated. Here, we explored the pathways affected by FOS, based on identification of differentially expressed genes with ≥2-fold change (linear-fold change) in expression upon FOS treatment. Caco-2 cells were cultured for 24 h in high glucose-Dulbecco's modified Eagle medium supplemented with 10% fetal calf serum containing FOS. The differentially expressed genes in these cells, identified using mRNA microarray analysis, were categorized using the pathway analysis and subsequently upregulated genes in typical pathways were subjected to protein network analysis. RT-qPCR was performed to validate the expression of selected genes. Treatment with 10% FOS enhanced the expression of a set of genes, such as ITGB8, ITGA6, SPP1, CAV1, LAMA3, ARHGAP5, and LAMC2, in the focal adhesion pathway. In addition, this treatment increased the expression of many genes involved in various inflammatory pathways, such as TNF, ITGA5, ITGB3, PTGS2, FGF2, FLNC, EDNRB, VEGFA, and MMP13. Protein network analysis showed that genes in the focal adhesion and endothelin pathways induced by FOS were closely associated with each other. FOS treatment of human intestinal absorptive-like cells enhances a set of genes in the focal adhesion and inflammation pathways.