No Evidence for Acquired Mutations Associated with Cytochrome bc 1 Inhibitor Resistance in 13,559 Clinical Mycobacterium tuberculosis Complex Isolates

New synergistic benzoquinone scaffolds as inhibitors of mycobacterial cytochrome bc1 complex to treat multi-drug resistant tuberculosis

Through a comprehensive molecular docking study, a unique series of naphthoquinones clubbed azetidinone scaffolds was arrived with promising binding affinity to Mycobacterial Cytbc1 complex, a drug target chosen to kill multi-drug resistant Mycobacterium tuberculosis (MDR-Mtb). Five compounds from series-2, 2a, 2c, 2g, 2h, and 2j, showcased significant in vitro anti-tubercular activities against Mtb H37Rv and MDR clinical isolates. Further, synergistic studies of these compounds in combination with INH and RIF revealed a potent bactericidal effect of compound 2a at concentration of 0.39 μg/mL, and remaining (2c, 2g, 2h, and 2j) at 0.78 μg/mL. Exploration into the mechanism study through chemo-stress assay and proteome profiling uncovered the down-regulation of key proteins of electron-transport chain and Cytbc1 inhibition pathway. Metabolomics corroborated these proteome findings, and heightened further understanding of the underlying mechanism. Notably, in vitro and in vivo animal toxicity studies demonstrated minimal toxicity, thus underscoring the potential of these compounds as promising anti-TB agents in combination with RIF and INH. These active compounds adhered to Lipinski's Rule of Five, indicating the suitability of these compounds for drug development. Particular significance of molecules NQ02, 2a, and 2h, which have been patented (Published 202141033473).

Characterization of Two Novel Inhibitors of the Mycobacterium tuberculosis Cytochrome bc1 Complex

Drug-resistant tuberculosis is a global health care threat calling for novel effective treatment options. Here, we report on two novel cytochrome bc1 inhibitors (MJ-22 and B6) targeting the Mycobacterium tuberculosis respiratory chain with excellent intracellular activities in human macrophages. Both hit compounds revealed very low mutation frequencies and distinct cross-resistance patterns with other advanced cytochrome bc1 inhibitors.

Tuberculosis: Past, present and future of the treatment and drug discovery research

Tuberculosis (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis. Despite decades of research driving advancements in drug development and discovery against TB, it still leads among the causes of deaths due to infectious diseases. We are yet to develop an effective treatment course or a vaccine that could help us eradicate TB. Some key issues being prolonged treatment courses, inadequate drug intake, and the high dropout rate of patients during the treatment course. Hence, we require drugs that could accelerate the elimination of bacteria, shortening the treatment duration. It is high time we evaluate the probable lacunas in research holding us back in coming up with a treatment regime and/or a vaccine that would help control TB spread. Years of dedicated and focused research provide us with a lead molecule that goes through several tests, trials, and modifications to transform into a ‘drug’. The transformation from lead molecule to ‘drug’ is governed by several factors determining its success or failure. In the present review, we have discussed drugs that are part of the currently approved treatment regimen, their limitations, vaccine candidates under trials, and current issues in research that need to be addressed. While we are waiting for the path-breaking treatment for TB, these factors should be considered during the ongoing quest for novel yet effective anti-tubercular. If these issues are addressed, we could hope to develop a more effective treatment that would cure multi/extremely drug-resistant TB and help us meet the WHO's targets for controlling the global TB pandemic within the prescribed timeline.

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Despite numerous drugs and vaccines undergoing clinical trials, we have not been able to control TB.

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Majority of articles list the advancements in the TB drug-discovery; here we review the limitations of existing treatments.

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Brief description of aspects to be considered for the development of one but effective drug/preventive vaccine.

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A glance at pediatric tuberculosis: the most neglected area of TB research which requires dedicated research efforts.

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A concise narrative for research aspects to be re-evaluated by both academia and pharmaceutical R&D teams.

Multi-Omics Technologies Applied to Tuberculosis Drug Discovery

Multi-omics strategies are indispensable tools in the search for new anti-tuberculosis drugs. Omics methodologies, where the ensemble of a class of biological molecules are measured and evaluated together, enable drug discovery programs to answer two fundamental questions. Firstly, in a discovery biology approach, to find new targets in druggable pathways for target-based investigation, advancing from target to lead compound. Secondly, in a discovery chemistry approach, to identify the mode of action of lead compounds derived from high-throughput screens, progressing from compound to target. The advantage of multi-omics methodologies in both of these settings is that omics approaches are unsupervised and unbiased to a priori hypotheses, making omics useful tools to confirm drug action, reveal new insights into compound activity, and discover new avenues for inquiry. This review summarizes the application of Mycobacterium tuberculosis omics technologies to the early stages of tuberculosis antimicrobial drug discovery.

Potential anti-TB investigational compounds and drugs with repurposing potential in TB therapy: a conspectus

The latest WHO report estimates about 1.6 million global deaths annually from TB, which is further exacerbated by drug-resistant (DR) TB and comorbidities with diabetes and HIV. Exiguous dosing, incomplete treatment course, and the ability of the tuberculosis bacilli to tolerate and survive current first-line and second-line anti-TB drugs, in either their latent state or active state, has resulted in an increased prevalence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and totally drug-resistant TB (TDR-TB). Although a better understanding of the TB microanatomy, genome, transcriptome, proteome, and metabolome, has resulted in the discovery of a few novel promising anti-TB drug targets and diagnostic biomarkers of late, no new anti-TB drug candidates have been approved for routine therapy in over 50 years, with only bedaquiline, delamanid, and pretomanid recently receiving tentative regulatory approval. Considering this, alternative approaches for identifying possible new anti-TB drug candidates, for effectively eradicating both replicating and non-replicating Mycobacterium tuberculosis, are still urgently required. Subsequently, several antibiotic and non-antibiotic drugs with known treatment indications (TB targeted and non-TB targeted) are now being repurposed and/or derivatized as novel antibiotics for possible use in TB therapy. Insights gathered here reveal that more studies focused on drug-drug interactions between licensed and potential lead anti-TB drug candidates need to be prioritized. This write-up encapsulates the most recent findings regarding investigational compounds with promising anti-TB potential and drugs with repurposing potential in TB therapy.