The carbonic anhydrase inhibitor ethoxzolamide inhibits the Mycobacterium tuberculosis PhoPR regulon and Esx-1 secretion and attenuates virulence

The purpose of this study was to examine how ethoxzolamide modulates gene M. tuberculosis gene expression at acidic pH. We observed that ethoxzolamide downregulates genes of the PhoPR regulon. Mtb strain CDC1551 was grown at 37C in T-25 vented, standing tissue culture flasks in 8 ml of buffered 7H9 medium seeded an initial OD of 0.2. Three conditions were examined with two biological replicates: 1) DMSO treated, pH 7.0, 2) DMSO treated, pH 5.7, 3) 40 µM ethoxzolamide treated, pH 5.7. The CDC1551(phoP::Tn) mutant was grown in a similar manner and treated with DMSO at pH 7.0 and 5.7. Following six days incubation, total bacterial RNA was extracted and analyzed as previously described.