ZFP36 and infection: Unlike ZFP36 which was persistently upregulated in both in vitro M cells and Caco-2 cells after WT S. Typhimurium and ΔspeG infection, the other 2 neuron-related genes, GABRQ and OPALIN, were significantly upregulated in only S. Typhimurium-infected Caco-2 cells (2.028- and 2.022-fold change, respectively; S2 Table), but not in uninfected or infected M cells (S3 and S5 Tables).