Project description:The emergence of multidrug resistant tuberculosis and the increasing level of resistance urges the search for alternative drugs in treatment. Several neuroleptics, like thioridazine, reveal activity against Mycobacterium tuberculosis. Thioridazine was even successfully applied in compassionate therapy of extensively drug resistant tuberculosis in patients when added to other second and third line antibiotics. The synergistic effects between thioridazine and other anti-tuberculosis drugs is usually assigned to the inhibition of efflux pumps by thioridazine. Using an unbiased proteomic approach, we set out to unravel the molecular mechanism of this potential new anti-tuberculosis component by examining the impact of continuous thioridazine exposure on the proteome of M. tuberculosis. We discovered that under the influence of thioridazine several proteins involved in the maintenance of the cell wall permeability barrier are differentially regulated, while none of the known mycobacterial efflux pumps was differentially regulated on the protein level. By assessing accumulation of fluorescent dyes in M. tuberculosis over time, we demonstrated that long-term drug exposure of M. tuberculosis indeed affected the mycobacterial cell envelope and increased the permeability towards both hydrophilic and hydrophobic compounds. Furthermore, we demonstrated that treatment of M. tuberculosis with thioridazine altered the composition of the plasma membrane. Thioridazine induced an increase in cell envelope permeability, and thereby the enhanced uptake of compounds, this could explain the previously reported synergistic effects between thioridazine and other anti-tuberculosis drugs. Although the hypothesis of higher intercellular drug concentrations by THZ has not changed in this study, the more exact knowledge on its mode of action is a major step forward. This new insight in the molecular mechanism of this anti-tuberculosis compound could facilitate further development of this class of drugs for application in drug therapy of multidrug resistant tuberculosis. In fact, the efficacy of many existing drugs could be improved significantly.
Project description: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 TCA1M-bM-^@M-^Ys 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.
Project description: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.
Project description:The emergence of multidrug resistant (MDR) Mycobacterium tuberculosis (Mtb) strains, resistant to the frontline anti-tubercular drugs rifampicin and isoniazid, forces treatment with less effective and toxic second-line drugs and stands to derail TB control efforts. However, the immune response to MDR Mtb infection remains poorly understood. Here, we determined the RNA transcriptional profile of in vitro generated macrophages to infection with either drug susceptible Mtb HN878 or MDR Mtb W_7642 infection.
Project description:The alarming rise of antimicrobial resistance in Mycobacterium tuberculosis coupled with the shortage of new antibiotics has made tuberculosis (TB) control a global health priority. Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the growth of multi-drug resistant isolates of M. tuberculosis. Repurposing NSAIDs, with known clinical properties and safety records, offers a direct route to clinical trials. Therefore we investigated the novel mechanisms of anti-mycobacterial action of the NSAID, carprofen. Integrative molecular and microbiological approaches revealed that carprofen, a bactericidal drug, inhibited bacterial drug efflux mechanisms. In addition, carprofen restricted mycobacterial biofilm-like growth, highlighting the requirement of efflux-mediated communicative systems for the formation of biofilms. Transcriptome profiling revealed that carprofen likely acts by inhibiting respiration through the disruption of membrane potential, which may explain why spontaneous drug-resistant mutants could not be raised due to the pleiotropic nature of carprofen’s anti-tubercular action. This immunomodulatory drug has the potential to reverse TB antimicrobial resistance by inhibiting drug efflux pumps and biofilm formation, and paves a new chemotherapeutic path for tackling tuberculosis.
Project description:Multi-drug resistance and latent infection are two major issues in current tuberculosis (TB) control and management. Capreomycin is an important drug used for TB with multi-drug resistance. A recent study also indicates that this drug possesses unique bactericidal activity against non-replicating TB bacilli among known anti-TB drugs. Thus, there is an urgent need for investigating the full-spectrum action of capreomycin. Here we conduct the first microarray-based study on capreomycin using the high-resolution Affymetrix oligonucleotide GeneChip system. The results indicate that capreomycin primarily acts on the information pathways but it also significantly affects cell wall, cell processes, intermediate metabolism and respiration in Mycobacterium tuberculosis. This study not only transcriptionally validates the specific molecular target, 16S rRNA, but also discovers potential new targets of capreomycin, including genes operating at the DNA level, such as Rv0054 (ssb) and Rv3715c (recR), as well as genes involved in cell division like Rv3260c (whiB2). In addition, the nuo gene cluster and the ATP synthase gene cluster are repressed. Keywords: Drug-induced Differential gene expression analysis
Project description:The pathogenesis of liver damage induced by anti-tuberculosis drugs is not fully understood, andcurrently, there is no clinically useful biomarker for early diagnosis and treatment.By comparing the differences in the expression of global gene transcripts in the serum of patients with and without anti-tuberculosis drugs induced liver injury, dysregulation genes not only provides a basis for studying pathogenesis, but also provides important information to find new targets for diagnosis and treatment of disease. We used microarrays to detail the global programme of gene expression in sera underlying anti-tuberculosis drug-induced liver injury and identified distinct classes of transcript during this process.
Project description:To understand the response of M. tuberculosis (MTB) to the first-line drug P218, we performed transcriptomics on MTB bacilli exposed to the drug.
Project description:To understand the response of M. tuberculosis (MTB) to the first-line drug clarithromycin, we performed transcriptomics on MTB bacilli exposed to the drug.
Project description:To understand the response of M. tuberculosis (MTB) to the first-line drug ethambutol, we performed transcriptomics on MTB bacilli exposed to the drug.