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:Knowing when a person was infected with Mycobacterium tuberculosis (M.tb) is critical as recent infection is the strongest clinical risk factor for progression to TB disease in immunocompetent individuals. However, time since M.tb infection is very difficult to determine in routine clinical practice. We determined whether DNA methylation patterns in the blood correlate with time since M.tb infection or exposure to develop a biomarker for recent exposure. As proof of concept, we found a DNA methylation signature that is present during early infection of mice that persists for at least 5 months post-infection.
Project description:In this study, RNA sequencing (Transcriptome sequencing) was employed to investigate the global transcriptome changes in the macrophages during the different strains of M.tb infection. THP-1 cells derived macrophages were exposed to the virulent M.tb strain H37Rv (Rv) or the avirulent M.tb strain H37Ra (Ra), and the M.tb BCG vaccine strain was used as a control. The cDNA libraries were prepared from M.tb infected macrophages and then sequenced.
Project description:Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis (M.tb) infection, remains a leading cause of morbidity and mortality world-wide. Circular RNAs are non-coding RNAs with diverse functions. However, most M.tb related circRNAs remain undiscovered. We used circRNA-seq technology to sequence the THP-1 cells infected with virulent and avirulent M.tb strains for 12 h.
Project description:Microparticles (MP) are small membranous particles (100-1000 nm) released under normal steady-state conditions and are thought to provide a communication network between host cells. Previous studies demonstrated that Mycobacterium tuberculosis (M.tb) infection of macrophages increased the release of MPs, and these MPs induced a proinflammatory response from uninfected macrophages in vitro and in vivo following their transfer into uninfected mice. To determine how M.tb infection modulates the protein composition of the MPs, and if this contributes to their proinflammatory properties, we compared the proteomes of MPs derived from M.tb-infected (TBinf-MP) and uninfected human THP-1 monocytic cells. MP proteins were analysed by GeLC-MS/MS with spectral counting revealing 68 proteins with statistically significant differential abundances. The 42 proteins increased in abundance in TBinf-MPs included proteins associated with immune function (7), lysosomal/endosomal maturation (4), vesicular formation (12), nucleosome proteins (4) and antigen processing (9). Prominent among these were the type I interferon inducible proteins, ISG15, IFIT1, IFIT2, and IFIT3. Exposure of uninfected THP-1 cells to TBinf-MPs induced increased gene expression of isg15, ifit1, ifit2, and ifit3 and the release of proinflammatory cytokines. These proteins may regulate the proinflammatory potential of the MPs and provide candidate biomarkers for M.tb infection.
Project description:This study aims to identify the specific miRNA of mycobacterium tuberculosis (M.tb) infected THP-1 by next-generation sequencing, and further to explore the role of miRNA in innate immunity against M.tb infection.Comprehensive analysis of the next-generation sequencing results showed that the expression of miR-99a-5p was significantly lower in the MTB infected THP-1 cells.
Project description:A subset of individuals with a high probability of exposure to M. tuberculosis (M.tb) appears to ‘resist’ established M.tb infection, as demonstrated by serially negative tuberculin skin test (TST) or IFN-γ release assay (IGRA) results. While these ‘resisters’ (RSTR) display IFN-γ-independent T cell responses to the M.tb-specific antigens ESAT-6 and CFP-10, it is currently unknown whether unique T cell functional programs are associated with this clinical outcome. We used multi-modal single-cell RNA, TCR sequencing, multi-parameter flow cytometry, and cytokine analysis in a discovery and validation format to compare the phenotypes and functions of M.tb-specific T cells between RSTRs and matched controls with ‘latent’ M.tb infection (LTBI). M.tb-specific T cells were clonally expanded in both RSTRs and LTBIs, confirming the priming of adaptive immune responses after M.tb exposure. However, M.tb-specific T cells derived from RSTRs showed enrichment of T regulatory as well as Th17-like functional programs compared to LTBIs, which were characterized by Th1*-like effector programs. Th17-like functional programs were also associated with a lack of progression to active TB among South African adolescents with LTBI, as well as bacterial control in published non-human primate studies. Together, these data suggest that ‘resisters’ may successfully control M.tb after exposure and immune priming and establish a set of T cell biomarkers to facilitate further study of this important clinical phenotype.
Project description:Mycothiol (MSH) and ergothioneine (ERG) are thiols able to compensate for each other to protect mycobacteria such as Mycobacterium smegmatis against oxidative stress. Gamma-glutamylcysteine (GGC), another thiol and an intermediate in ERG biosynthesis has detoxification abilities. Five enzymes are involved in ERG biosynthesis, namely EgtA, EgtB, EgtC, EgtD and EgtE. The role of these enzymes in the production of ERG had been unclear. On the other hand, the enzyme MshA is known to be essential for MSH biosynthesis. In this manuscript, we describe the raw data of the generation and characterization of Mycobacterium tuberculosis (M.tb) mutants harbouring a deletion of the gene coding for each of these enzymes, and the raw data of the phenotypic characterization of the obtained thiol-deficient M.tb mutants. Through a high throughput screening approach, compounds not previously used in a tuberculosis (TB) regimen were identified. Raw data depicting the effect of these compounds on the generated thiol-deficient M.tb mutants, on the production of reactive oxygen species (ROS) and thiols in the M.tb wild type strain are described in this study.
Project description:Tuberculosis (TB) is one of the leading causes of death due to a single infectious agent and is considered a global threat killing over 4,300 people every day. Upon infection, Mycobacterium tuberculosis (M.tb) deposits in the alveoli and encounters the lung mucosa or alveolar lining fluid (ALF), whose primary function is to keep the lung’s health intact, dictating host-cell interactions. Age-associated changes to innate soluble components in the ALF lead to increased susceptibility of the elderly population to respiratory infectious diseases such as TB. We previously determined that increased M.tb replication in human macrophages and alveolar epithelial cells (ATs) is mediated by age-associated changes in human ALF. In this study, we determine the transcriptional profile of M.tb when exposed to healthy human ALF from adult (A-ALF) or elderly (E-ALF) individuals prior and during intracellular replication in ATs, using A549 cells as a model. Prior to infection, exposure of M.tb to E-ALF upregulates several genes associated with the ESX-4 secretion system as well as immunomodulatory proteins linked to the ESX-5 secretion system. It additionally increases the expression of genes related to phospholipases, phosphatases, and proteases, which are important virulence factors in the establishment of M.tb infection. Importantly, we present the first transcriptomic analysis of the impact of the elderly lung mucosa on M.tb pathogenesis during intracellular replication in ATs. Interestingly, exposure to E-ALF altered expression of key genes related to the ESX-5 secretion system during infection. Additionally, compared to the A-ALF group, there was enhanced expression of genes associated with PDIMs biosynthesis and translocation to the cell surface. Lastly, E-ALF-exposed M.tb exhibits upregulation of genes linked to ROS defense mechanisms during ATs infection. Overall, these findings demonstrate how altered ALF functions in old age can impact the M.tb metabolic status, enabling greater adaptation and increased survival in the host cells.
Project description:Purpose: Understanding the functional genomics of M.tb (Mycobacterium tuberculosis) and development of novel anti-M.tb drugs and vaccines needs an efficient gene edit tool. The aim of this study was to describe an easy and efficient gene edit tool for functional genomics study of M.tb. Method: A plasmid was designed containing mini CRISPR array and 400bp up and downside homologues DNA sequences from the target gene interposed by EGFP or BFP. This plasmid was transformed into M.tb that guided the endogenous CRISPR system of M.tb to cut the target gene and insert EGFP or BFP through homologues ends joining. The EGFP/BFP insertion was confirmed and the total genomic was extracted from mutated and wild type strains and subjected to High-throughput DNA sequencing. Results: The raw data was filtered by Trimmomatic and the clean reads were mapped to M.tb H37Ra reference genome with bwa 99.94%, and 99.97% genome of wag31 and esxQ deletion strains were covered respectively.