Project description:Tuberculosis (TB) remains a deadly disease. The genetic diversity of Mycobacterium tuberculosis was neglected in the past, but is increasingly recognized as a determinant of immune responses and clinical outcomes of TB. However, how this bacterial diversity orchestrates immune responses to direct differences in TB severity remains unknown. We studied 681 patients with pulmonary TB and found that phylogenetically related M. tuberculosis isolates from cases with mild disease induced robust cytokine responses in macrophages. In contrast, isolates associated with severe TB cases failed to do so. Using representative isolates, we show that M. tuberculosis inducing a low cytokine response in macrophages also diminished activation of cytosolic surveillance systems, including cGAS and the inflammasome, suggesting a novel mechanism of immune escape. Isolates exhibiting this evasion strategy carried mutations in various components of the ESX-I secretion system. We conclude that host interactions with different M. tuberculosis strains results in variable TB severity.
Project description:Out of the 10 million of tuberculosis (TB) cases estimated in the world, around 14% are isoniazid (INH) resistant among new cases and 29% among previously treated cases in the last decade. INH is one of the oldest but also one of the more potent drugs to eliminate Mycobacterium tuberculosis (Mtb), the causing agent of TB. Because of the efficiency of isoniazid (INH) against Mycobacterium tuberculosis (Mtb), many studies are still focused in better understand its role in different bacterial metabolic pathways. We recently conducted a study that evaluated the changes in the protein abundance at different cellular fractions when clonal strains of Mtb developed INH resistance in the clinical and laboratory setting. Here, we want to establish which of the protein changes occurred or started because of the initial exposure to INH. Additionally, we wanted to evaluate if those changes happen differently in strains that are sensitive or resistant to INH, evaluating different cellular compartments from two different genetic lineages of Mtb. For this purpose, we analyzed the proteome of each cellular compartment (cytosol, cell wall, membrane and secreted proteins) through liquid chromatography (nano-HPLC) coupled to mass spectrometry using the Orbitrap Velos instrument and a t-test to perform the statistical analysis for each pair comparison.
Project description:Currently available model organisms such as Mycobacterium smegmatis and Mycobacterium bovis Bacillus Calmette-Guérin (BCG) have significantly contributed to our understanding of tuberculosis (TB) biology, these models have limitations such as differences in genome size, growth rates and virulence. Attenuated Mycobacterium tuberculosis strains may provide more representative, safer models to study M. tuberculosis biology. For example, the M. tuberculosis ΔleuDΔpanCD double auxotroph, has undergone rigorous in vitro and in vivo safety testing. Like other auxotrophic strains, this has subsequently been approved for use in biosafety level (BSL) 2 facilities. Auxotrophic strains have been assessed as models for drug-resistant M. tuberculosis and for studying latent TB. These offer the potential as safe and useful models, but it is important to understand how well these recapitulate salient features of non-attenuated M. tuberculosis. We therefore performed a comprehensive comparison of M. tuberculosis H37Rv and M. tuberculosis ΔleuDΔpanCD. These strains demonstrated similar in vitro and intra-macrophage replication rates, similar responses to anti-TB agents and whole genome sequence conservation. Shotgun proteomics analysis suggested that M. tuberculosis ΔleuDΔpanCD has an increased propensity to enter a dormant state during acid stress, which has been verified using a dual-fluorescent replication reporter assay. Importantly, infection of human peripheral blood mononuclear cells with the 2 strains elicited comparable cytokine production, demonstrating the suitability of M. tuberculosis ΔleuDΔpanCD for immunological assays. We provide comprehensive evidence to support the judicious use of M. tuberculosis ΔleuDΔpanCD as a safe and suitable model organism for M. tuberculosis research, without the need for a BSL3 facility.
Project description:The emergence of drug resistance among tuberculosis (TB) patients is often associated with their non-compliance to the length of the chemotherapy, which can reach up to 2 years for the treatment of multi-drug-resistant (MDR) TB. Drugs that would kill TB faster and would not lead to the development of drug resistance could shorten chemotherapy significantly. In Escherichia coli, the common mechanism of cell death by bactericidal antibiotics is the generation of highly reactive hydroxyl radicals via the Fenton reaction. Since ascorbic acid (vitamin C) is known to drive the Fenton reaction, we tested whether the Fenton reaction could lead to a bactericidal event in Mycobacterium tuberculosis by treating M. tuberculosis cultures with vitamin C. Here, we report that the addition of vitamin C to drug-susceptible, MDR and extensively drug-resistant (XDR) M. tuberculosis strains results in sterilization of the cultures in vitro. We show that the sterilizing effect of vitamin C on M. tuberculosis was dependent on the production of high ferrous ion levels and reactive oxygen species. Although, this potent sterilizing activity of vitamin C against M. tuberculosis in vitro was not observed in mice, we believe this activity needs further investigation. Comparison of vitamin C treated Mycobacterium tuberculosis transcriptome relative to untreated; Three biological replicates, second is a dye flip
Project description:Transcriptional profiling of Mycobacterium tuberculosis H37Rv strains comparing control DMSO treated strains with Lupulone treated strains. Goal was to determine the effects of Lupulone against Mycobacterium tuberculosis H37Rv strains.
Project description:Transcriptional profiling of Mycobacterium tuberculosis H37Rv strains comparing control DMSO treated strains with Linezolid treated strains. Goal was to determine the effects of Linezolid against Mycobacterium tuberculosis H37Rv strains.
Project description:The emergence of drug resistance among tuberculosis (TB) patients is often associated with their non-compliance to the length of the chemotherapy, which can reach up to 2 years for the treatment of multi-drug-resistant (MDR) TB. Drugs that would kill TB faster and would not lead to the development of drug resistance could shorten chemotherapy significantly. In Escherichia coli, the common mechanism of cell death by bactericidal antibiotics is the generation of highly reactive hydroxyl radicals via the Fenton reaction. Since ascorbic acid (vitamin C) is known to drive the Fenton reaction, we tested whether the Fenton reaction could lead to a bactericidal event in Mycobacterium tuberculosis by treating M. tuberculosis cultures with vitamin C. Here, we report that the addition of vitamin C to drug-susceptible, MDR and extensively drug-resistant (XDR) M. tuberculosis strains results in sterilization of the cultures in vitro. We show that the sterilizing effect of vitamin C on M. tuberculosis was dependent on the production of high ferrous ion levels and reactive oxygen species. Although, this potent sterilizing activity of vitamin C against M. tuberculosis in vitro was not observed in mice, we believe this activity needs further investigation.
Project description:Pyrazinamide (PZA) is one of the first line antibiotics used for the treatment of tuberculosis (TB). we have used human monocyte and a mouse model of pulmonary TB to investigate whether treatment with PZA, in addition to its known anti-mycobacterial properties, modulate the host immune response during Mycobacterium tuberculosis (Mtb) infection.
Project description:We report a pilot investigation for poly-A RNAs differentially expressed during Mycobacterium tuberculosis infection. Participation in this investigation from March 2010 to July 2013 was voluntary, only subjects that were >18 years old and that informed written consent were considered eligible. The recruitment of tuberculosis (TB) patients was done at public hospitals in Rio de Janeiro, Brazil. The diagnostic criteria for active pulmonary tuberculosis was at least one AFB (acid-fast bacilli) -positive sputum sample for M. tuberculosis and/or positive sputum culture and/or compatible clinical evolution for pulmonary TB and less than 15 days of anti-TB treatment and was in accordance with those of the Brazilian Ministry of Health. Blood was collected from recent close contacts (rCt) and active tuberculosis (TB) index cases (n=6). Latent TB infection (LTBI) was accessed by both tuberculin skin test (TST, cut-off = 5mm) and in house interferon-gamma release assays (IGRA, cut-off = 100 pg/ml), therefore, 12 rCt were classified as uninfected controls and 16 with LTBI. Subsequently, the sequencing was performed following the standard protocols on Illumina HiSeq® 2500 Sequencing System (Illumina, San Diego, CA) running 100 bp paired-end reads (PE100) and generating approximately 30 million reads passing filter for each sample to produce the mRNA reads. Mining these RNAseq data, highly prominent modulation of DOCK9, EPHA4, and NPC2 mRNA expression was observed in the TB samples, indicating that they might have a role in TB pathogenesis. These differential modulations upon M. Tuberculosis infection were further validated by additional evidences in larger cohorts from different geographical areas.
Project description:Tuberculosis (TB) is still a major global health challenge, killing over 1.5 million people each year, and hence, there is a need to identify and develop novel treatments for Mycobacterium tuberculosis (M. tuberculosis). The prevalence of infections caused by nontuberculous mycobacteria (NTM) is also increasing and has overtaken TB cases in the United States and much of the developed world. Mycobacterium abscessus (M. abscessus) is one of the most frequently encountered NTM and is difficult to treat. We describe the use of drug-disease association using a semantic knowledge graph approach combined with machine learning models that has enabled the identification of several molecules for testing anti-mycobacterial activity. We established that niclosamide (M. tuberculosis IC90 2.95 μM; M. abscessus IC90 59.1 μM) and tribromsalan (M. tuberculosis IC90 76.92 μM; M. abscessus IC90 147.4 μM) inhibit M. tuberculosis and M. abscessus in vitro. To investigate the mode of action, we determined the transcriptional response of M. tuberculosis and M. abscessus to both compounds in axenic log phase, demonstrating a broad effect on gene expression that differed from known M. tuberculosis inhibitors. Both compounds elicited transcriptional responses indicative of respiratory pathway stress and the dysregulation of fatty acid metabolism. Further testing against drug-resistant isolates and other NTM is warranted to clarify the usefulness of these repurposed drugs for mycobacteria.