Project description:Mycobacterium tuberculosis (Mtb) is known to subvert immune responses to establish infection and cause disease. Thus, host-directed therapy (HDT), as adjunctive treatment to traditional antitubercular regimens, is an attractive strategy. Statins are a class of drugs used to lower cholesterol levels by inhibiting the 3-hydroxy-3-methylglutaryl coenzyme A reductase, a crucial enzyme in the cholesterol biosynthesis pathway. Here, we conducted a preclinical animal study aimed at comparing the bactericidal activities of the standard TB regimen (rifampin, isoniazid, pyrazinamide and ethambutol; RHZE) with or without escalating doses of pravastatin against chronic TB in BALB/c mice. Antibiotics were given five times weekly for 8 weeks (continuous phase) beginning 6 weeks after infection. Treatment with RHZE plus pravastatin at doses ranging from 30 mg/kg to 180 mg/kg demonstrated a dose-dependent increase in bactericidal activity, reducing lung bacillary counts by 0.2–0.6 log10, 0.3–0.6 log10 and 0.3–0.8 log10 compared to RHZE alone at weeks 2, 4 and 8, respectively. After 8 weeks of treatment, the degree of lung inflammation correlated with the bactericidal activity of each drug regimen. In order to gain insight into the anti-TB mechanism of action of pravastatin in vivo, the lungs of mice treated with pravastatin adjunctive therapy and those treated with RHZE alone were analyzed by whole-genome microarrays and RT-PCR. Mouse sera were studied by multiplex enzyme-linked immunosorbent assays. Treatment with pravastatin for 1 month had a profound effect on the global transcription in mouse lungs.
Project description:The global burden of tuberculosis (TB) is aggravated by the continuously increasing emergence of drug resistance, highlighting the need for innovative therapeutic options. The concept of host-directed therapy (HDT) as adjunctive to classical antibacterial therapy with antibiotics represents a novel and promising approach for treating TB. Here, we have focused on repurposing the clinically used anticancer drug tamoxifen, which was identified as a molecule with strong host-directed activity against intracellular Mycobacterium tuberculosis (Mtb). Using a primary human macrophage Mtb infection model, we demonstrate the potential of tamoxifen against drug-sensitive as well as drug-resistant Mtb bacteria. The therapeutic effect of tamoxifen was confirmed in an in vivo TB model based on Mycobacterium marinum infection of zebrafish larvae. Tamoxifen had no direct antimicrobial effects at the concentrations used, confirming that tamoxifen acted as an HDT drug. Furthermore, we demonstrate that the antimycobacterial effect of tamoxifen is independent of its well-known target the estrogen receptor (ER) pathway, but instead acts by modulating autophagy, in particular the lysosomal pathway. Through RNA sequencing and microscopic colocalization studies, we show that tamoxifen stimulates lysosomal activation and increases the localization of mycobacteria in lysosomes both in vitro and in vivo, while inhibition of lysosomal activity during tamoxifen treatment partly restores mycobacterial survival. Thus, our work highlights the HDT potential of tamoxifen and proposes it as a repurposed molecule for the treatment of TB.
Project description:Severe malaria encompasses a range of syndromes manifesting systemically or in diverse organs. These are believed to represent the end-stage processes of local parasite sequestration and inflammatory cascades. Classical anti-malarial drugs target parasites only. In treatment of severe disease, adjunctive therapies capable of controlling the inflammatory processes could be beneficial. Innate defense regulator (IDR) peptides display multiple immune modulatory activities. In this study, we assessed peptide IDR-1018, which shows promise as an anti-inflammatory drug, as a lead candidate for adjunctive host-directed therapy of established disease in the P. berghei ANKA model of experimental cerebral malaria (ECM). Intravenously administered IDR-1018 partially protected mice from ECM both prophylactically and in adjunctive treatment with classical anti-malarial drugs. We used transcriptional data from spleens and brains taken early in infection (day 3) of prophylactically treated mice to investigate the protective mechanisms. The microarrays compared spleens and brains from nine IDR-1018 i.v. treated, infected mice (IDR-1018-treated infected) with three saline i.v. treated infected mice (saline-treated infected) and three uninfected untreated control mice (controls). RNA samples were hybridized in randomized order to five Illumina WG-6 v2 BeadChips . No technical replicates were performed.
Project description:Severe malaria encompasses a range of syndromes manifesting systemically or in diverse organs. These are believed to represent the end-stage processes of local parasite sequestration and inflammatory cascades. Classical anti-malarial drugs target parasites only. In treatment of severe disease, adjunctive therapies capable of controlling the inflammatory processes could be beneficial. Innate defense regulator (IDR) peptides display multiple immune modulatory activities. In this study, we assessed peptide IDR-1018, which shows promise as an anti-inflammatory drug, as a lead candidate for adjunctive host-directed therapy of established disease in the P. berghei ANKA model of experimental cerebral malaria (ECM). Intravenously administered IDR-1018 partially protected mice from ECM both prophylactically and in adjunctive treatment with classical anti-malarial drugs. We used transcriptional data from spleens and brains taken early in infection (day 3) of prophylactically treated mice to investigate the protective mechanisms.
Project description:Infectious diseases, such as Mycobacterium tuberculosis (Mtb)-caused tuberculosis (TB), remain a global health threat exacerbated by increasing drug resistance. Host-directed therapy (HDT) is a complementing strategy for infection treatment through targeting host immune mechanisms. However, the limited understanding of the host factors and their regulatory mechanisms involved in host immune defense against infections has impeded HDT development. Here, we identify the E3 ubiquitin ligase tripartite motif-containing 27 (TRIM27) elicits host protective immunity against Mtb. Mechanistically, TRIM27 enters host cell nucleus upon Mtb infection to function as a transcription activator of transcription factor EB (TFEB). TRIM27 binds to TFEB promoter and the TFEB transcription factor cAMP responsive element binding protein 1 (CREB1), thus enhancing CREB1-TFEB promoter binding affinity and promoting CREB1 transcription activity towards TFEB, eventually leading to autophagy activation and pathogen clearance. Thus, TRIM27 contributes to host anti-Mtb immunity and targeting TRIM27/CREB1/TFEB axis serves as a promising HDT-based TB treatment.
Project description:Tuberculosis (TB) is a chronic granulomatous disease caused by the pathogen Mycobacterium tuberculosis. The success of M. tuberculosis can be attributed to its ability to evade protective host immune responses and its recalcitrance to antimicrobial chemotherapy. Detailed understanding of protective host immune response to TB is still lacking and there are limited reports that characterize host responses to TB at the site of disease. Furthermore, although cure of the majority of patients treated with the standard 6-month multidrug regimen indicates that treatment is highly effective, approximately 4-10% of clinically cured patients will develop recurrent disease within the first 12 months after completing therapy. We therefore analyzed BALF supernatant proteomes from pulmonary TB patients and patients at the end of standard anti-TB treatment to gain a better understanding of the host response at the site of disease. This would not only aid our understanding of localised host responses during TB disease, but could allow us to identify protein signatures associated with active TB disease or clinical cure.
Project description:Monocyte miRNAs govern both protective and pathological responses during tuberculosis through their differential expression and emerged as potent target for biomarker discovery and host-directed therapeutics. Thus, our profound interest is to look at the miRNA profile of sorted monocytes across TB disease spectrum (drug-resistance TB (DR-TB), drug-sensitive TB (DS-TB) and latent TB) and healthy individuals (HC) to understand the underlying pathophysiology and their regulatory mechanism.
Project description:The lengthy and complicated multidrug therapy currently available to treat active tuberculosis (TB) infection has contributed to medical non-adherence and the emerging problems of multidrug-resistant (MDR)- and extensively drug-resistant (XDR)-TB, which are particularly deadly in the setting of HIV co-infection. The prolonged therapy required to eradicate TB infection is believed to reflect the ability of Mycobacterium tuberculosis (Mtb) to persist within host necrotic granulomas in a non-replicating state characterized by antibiotic tolerance to bactericidal drugs, which predominantly target actively dividing tubercle bacilli. The stringent response enzyme, RelMtb, is essential for Mtb survival under physiologically relevant stress conditions in vitro and in the lungs of mice and guinea pigs. A library of over 2 million compounds was screened in RelMtb-inhibition assays and whole-cell screens under conditions in which RelMtb is essential. A total of 178 RelMtb inhibitor candidates, representing 18 unique scaffolds, were identified and 39 compounds were tested against nutrient-starved wild-type Mtb. The antibiotic susceptibility of a relMtb deletion mutant (Δrel) was studied during nutrient starvation and chronic infection in mice, and isoniazid and RelMtb inhibitor candidates were tested for synergy against nutrient-starved wild-type Mtb and Δrel using checkerboard assays. The minimum bactericidal concentration of isoniazid was 500-fold lower against Δrel relative to wild type during nutrient starvation, and the potent bactericidal activity of isoniazid was maintained against Δrel during chronic infection in the lungs of mice. Inhibition of RelMtb appears to be a promising new approach to target Mtb persisters, with the potential to shorten the duration of treatment for drug-susceptible and drug-resistant TB. We used microarray to characterize the transcriptomic profiles of the wild type and Δrel during nutrient starvation. The RelMtb inhibitor, (E)-4-(3-methyl-4-(2-(4-methylthiazol-5-yl)ethoxy)styryl)benzoic acid, killed wild-type Mtb and prevented isoniazid tolerance during nutrient starvation. Treatment of nutrient-starved wild-type with the RelMtb inhibitor led to downregulation of the RelMtb regulon. Transcriptomic analysis revealed an altered gene expression in Δrel and wild-type treated with RelMtb inhibitor during nutrient starvation.
Project description:In view of emerging drug-resistant tuberculosis, host directed therapies are urgently needed to improve treatment outcomes with currently available anti-tuberculosis therapies. One option is to interfere with the formation of lipid-laden “foamy” macrophages in the infected host. Here, we provide evidence that WNT6, a member of the evolutionary conserved WNT signaling pathway, promotes foam cell formation by regulating key lipid metabolic genes including acetyl-CoA carboxylase-2 (ACC2) during pulmonary TB. In addition, we demonstrate that Mycobacterium tuberculosis (Mtb) facilitates its intracellular growth and dissemination in the host by exploiting the WNT6-ACC2 pathway. Using genetic and pharmacological approaches, we show that lack of functional WNT6 or ACC2 significantly reduces intracellular TAG levels, Mtb growth and necrotic cell death of macrophages. In combination with the anti-TB drug isoniazid, pharmacological inhibition of ACC2 improved anti-mycobacterial treatment in vitro and in vivo. Therefore, we propose the WNT6-ACC2 signaling pathway as a promising target for a host-directed therapy to reduce intracellular replication of Mtb by modulating neutral lipid metabolism.
Project description:Pulmonary macrophages have two distinct ontogenies: long-lived embryonically-seeded alveolar macrophages (AM) and bone marrow-derived macrophages (BMDM). Here, we show that after infection with a virulent strain of Mycobacterium tuberculosis (H37Rv), primary murine AM exhibit a unique transcriptomic signature characterized by metabolic reprogramming distinct from conventional BMDM. In contrast to BMDM, AM failed to shift from oxidative phosphorylation (OXPHOS) to glycolysis and consequently were unable to control infection with an avirulent strain (H37Ra). Importantly, healthy human AM infected with H37Ra equally demonstrated diminished energetics, recapitulating our observation in the murine model system. However, the results from seahorse showed that the shift towards glycolysis in both AM and BMDM was inhibited by H37Rv. We further demonstrated that pharmacological (e.g. metformin or the iron chelator desferrioxamine) reprogramming of AM towards glycolysis reduced necrosis and enhanced AM capacity to control H37Rv growth. Together, our results indicate that the unique bioenergetics of AM renders these cells a perfect target for Mtb survival and that metabolic reprogramming may be a viable host adjunctive therapy against TB.