Biology subjects

Madan, M.

Publications and source records attributed to Madan, M..

3 recordsLinked to original sources

bioRxiv2025

Rapid Screening and Validation of Intracellularly Active Antimycobacterial Compounds with Efficacy in Cellular and Murine Tuberculosis Models

The discovery of effective intracellular antimycobacterial agents is limited by the slow growth of Mycobacterium tuberculosis (Mtb) and a lack of scalable models that effectively replicate host-pathogen interactions. To address this, we established a robust ex vivo infection model using human monocyte-derived THP-1 macrophages and the fast-growing pathogenic surrogate Mycobacterium marinum (Mmar) which recapitulates key features of Mtb intracellular infection, including macrophage colonization and innate immune activation. This model supports medium-throughput screening workflows for assessing antibiotic-mediated control of intracellular mycobacteria. Using this platform, we screened FDA-approved antipsychotics and identified the phenothiazines- trifluoperazine (TFP) and fluphenazine (FFP), as potent adjuncts to frontline anti-tuberculosis therapy (ATT). Combinations of either phenothiazine with frontline TB drugs enhanced intracellular bacterial clearance more effectively than the previously reported antidepressant sertraline, initiating significant control within 12 hours of treatment in macrophages. In murine models of TB infection, TFP and FFP further potentiated bacterial clearance and tissue recovery when used in combination with standard anti-TB therapy (ATT). Together, our results validate the THP1-Mmar infection model as a rapid, robust, and scalable platform for identifying intracellular antimycobacterial agents and host-directed therapeutics, offering a valuable tool to accelerate TB drug discovery and development.

microbiology↗

bioRxiv2025

Macrophage Cholesterol Homeostasis Underpins the role of Sertraline as an Adjunctive Agent in Tuberculosis Therapy.

Cellular metabolism plays a deterministic role in the macrophage responses to intracellular pathogens such as Mycobacterium tuberculosis (Mtb) and infection control. Here, we demonstrate that the significant rewiring of the macrophage cholesterol metabolism by sertraline (SRT), an FDA-approved antidepressant, effectively enhances bacterial control. SRT, by virtue of its potent cationic amphiphilicity leads to the accumulation of lysosomal cholesterol in macrophages and activating the transcription factor SREBP2 and enhancing cholesterol biosynthesis. By specific gene silencing and biochemical inhibition assays, we further demonstrate that this metabolic reprogramming promotes lysosomal membrane permeabilization, mitochondrial reactive oxygen species (ROS) generation, heightened IL-1{beta} release, collectively enhancing macrophage bactericidal activity. Our results thus highlight a previously underappreciated link between cholesterol homeostasis and inflammasome activation, which contributes to improved Mtb clearance in the presence of adjunctive sertraline therapy. Statement of significanceTuberculosis remains a leading cause of global mortality, and treatment success is limited due to a long treatment regimen. This study identifies macrophage cholesterol homeostasis as a central pathway to enhance anti-tubercular therapy. We show that Sertraline, an FDA-approved antidepressant, a cationic amphiphilic drug (CAD), reprograms cholesterol trafficking through NPC1 inhibition. This drives the consequential processing of the master regulator SREBP2, accompanied by lysosomal membrane permeabilization. Collectively, these lead to mitochondrial ROS production and activation of NLRP3 signalling, boosting inflammasome-mediated bacterial clearance. By establishing cholesterol sequestration as the mechanistic basis of host-directed activity of sertraline and distinguishing it from ineffective CADs, our work provides a mechanistic framework for developing cholesterol-modulating host-directed adjuncts to improve TB treatment outcomes. Graphical abstract: SRT induced lysosomal cholesterol accumulation results in enhanced bacterial control via inflammasome activation O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=101 SRC="FIGDIR/small/665474v3_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@1019b4dorg.highwire.dtl.DTLVardef@7b0ae8org.highwire.dtl.DTLVardef@9297eorg.highwire.dtl.DTLVardef@1832bef_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

Sertraline enhances bacterial control by improving the pharmacodynamic -pharmacokinetic properties of frontline TB drugs

Given the need for innovative interventions for tackling the burden of TB, host directed therapies have emerged as a promising alternative in recent times. The combination of sertraline with frontline TB drugs has shown excellent promise in the murine models of infection in imparting better bacterial control and increasing host survival. We tested if the addition of sertraline worked to increase bacterial clearance in the random bred guinea pig model of TB infection that mimics the inter individual heterogeneity observed in the human response to infection. The combination of sertraline and frontline TB drugs effectively reduced bacterial burdens in the tissues of guinea pigs significantly better than the drugs alone with a marked betterment of lung histopathology. In order to evaluate the effect of sertraline on the pharmacodynamic properties of TB drugs, concentrations of the drugs were estimated in tissues at different time intervals over a period of 24h of administration to rats. Overall, addition of sertraline did not alter TB drug distribution or clearance from the animals, although enriching drug amounts transiently between 3-6 h in the different tissues. We thus highlight the advantage of an adjunct TB therapy with the inclusion of sertraline, an FDA approved antidepressant, in improving the PKPD of TB drugs and imparting better infection control in diverse models of infection.

microbiology↗