No abstract

SLC26A3 (downregulated in adenoma, DRA), Cl−/ anion exchanger, is highly expressed in the luminal membrane of intestinal epithelial cells, and loss‐of‐function mutations in this gene result in congenital chloride diarrhea caused by detect of chloride absorption and bicarbonate secretion in the intestine. Here, we report development of the selective small‐molecule inhibitors of DRA for the investigation of the effect of DRA inhibition on constipation and metabolic acidosis. A screen of ~50,000 compounds using a cell‐based high‐throughput screening (HTS) assay revealed four novel chemical compounds of DRA inhibitors that fully blocked Cl−/I− exchange activity of DRA with IC50 < 10 μM. The hit compounds strongly inhibited both Cl−/I− and Cl−/HCO3− exchange activity of DRA. Structure‐activity relationship were performed on the potent inhibitor classes identified in the screening. The potent inhibitor, DI330, significantly blocked Cl−/I− exchange activity of DRA (IC50 of ~30 nM) but it did not affect the activity of SLC26A4 (pendrin), SLC26A7, SLC26A9, CFTR and ANO1. The DI330 identified here may be useful tools for pharmacological dissection of DRA and drug discovery for treating constipation and metabolic acidosis.