The expression of NHE3 and DRA, the main transporter proteins regulating colonic Na+ inward transport and the main transporter protein regulating Cl−/HCO3- exchange in the apical membrane of mammalian intestinal epithelial cells, respectively, can be inhibited by the rising TNF-α expression in ulcerative colitis (39, 40). The gene discussed is SLC26A3; the disease is ulcerative colitis.