Objective: To establish the microfold (M)-like cell model in vitro and identify M-like cells through detecting the capacity of transporting fluorescent beads and the levels of the associated genes, and to observe the effects of lymphocyte culture supernatants stimulated by concanavalin A (Con A) from different lymphoid tissues on the differentiation of Caco2 cells into M-like cells.
Methods: The isolated lymphocytes of Peyer's patch (PP), mesenteric lymph node (MLN) and spleen (Sp) were incubated with 3 μg/mL Con A for 3 days. The culture supernatants were collected and co-cultured with Caco2 cells. The fluorescent bead suspension was added into the upper compartment of the Transwell™ inserts, and then basolateral solutions were then sampled and analyzed. The number of transported fluorescent beads was measured by flow cytometry. The expressions of M-like cells-associated genes, such as chemokine (C-C motif) ligand 20 (CCL20), claudin4 (CLDN4), tumor necrosis factor receptor superfamily member 9 (TNFRSF9), and Spi-B were detected by reverse transcription PCR.
Results: Compared with blank control group, the number of fluorescent beads transported by induced Caco2 cells and the levels of CCL20, CLDN4, TNFRSF9 and Spi-B mRNAs significantly increased in induced Caco2 cells treated with the culture supernatants of lymphocytes from PP, MLN and Sp. After Con A stimulation, the number of fluorescent beads transported by induced Caco2 cells and the levels of CCL20, CLDN4, TNFRSF9 and Spi-B mRNAs were higher than those in the unstimulated group.
Conclusion: The lymphocyte culture supernatants stimulated or unstimulated by Con A can induce the transdifferentiation of Caco2 cells into M-like cells.