TCA1 Stimulon in Mycobacterium tuberculosis

A cell-based phenotypic screen for inhibitors of biofilm formation in Mycobacterium tuberculosis (Mtb) identified the small molecule TCA1, which has bactericidal activity against both drug susceptible and drug resistant Mtb, and synergizes with rifampicin (RIF) or isoniazid (INH) in sterilization of Mtb in vitro. In addition, TCA1 has bactericidal activity against non-replicating Mtb in vitro and is efficacious in acute and chronic Mtb infection mouse models, both alone and in combination with INH or RIF. Transcriptional analysis revealed that TCA1 down-regulates genes known to be involved in Mtb dormancy and drug tolerance. Mutagenesis and affinity-based methods identified DprE1 and MoeW, enzymes involved in cell wall and molybdenum cofactor biosynthesis, respectively, as the targets responsible for TCA1’s activity. These in vitro and in vivo results indicate that TCA1functions by a novel mechanism and suggest that it may be the first product of a promising new approach for the development of anti-tuberculosis drugs. Transcriptional profile of TCA1-treated cells relative to DMSO-treated control. Three biological replicates, third is a dye flip.