Full-length RNA profiling of Mycobacterium tuberculosis with SEnd-seq
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ABSTRACT: Mycobacterium tuberculosis (Mtb) is a bacterial pathogen that causes tuberculosis (TB), an infectious disease that inflicts major health and economic costs around the world. Mtb encounters diverse environments during its lifecycle and responds to these changes by reprogramming its transcriptional output. However, the mechanisms and regulation of Mtb transcription remains poorly understood. In this work, we simultaneously determine the 5' and 3' ends of individual RNA molecules in Mtb cells using the SEnd-seq method, which enables us to profile the Mtb transcriptome at high resolution. Unexpectedly, we find that most Mtb transcripts are incomplete, with their 5' ends aligned at transcription start sites and 3' ends located 200-500 nucleotides downstream. Using native elongating transcript sequencing, we show that these short RNAs are mainly associated with paused RNA polymerases (RNAPs) rather than products of premature termination. We further show that the high propensity of Mtb RNAP to pause early in transcription is dependent on the binding of the sigma factor. Finally, we show that a translating ribosome promotes transcription elongation, suggesting a role for transcription-translation coupling in Mtb gene expression. In sum, our findings depict a mycobacterial transcriptome that prominently features incomplete transcripts resulting from RNAP pausing. We propose that the pausing phase constitutes an important transcriptional checkpoint in Mtb that allows the bacterium to adapt to new environments and could be exploited for TB therapeutics.
Project description:Tuberculosis (TB) is one of the deadliest infectious disorders in the world. To effectively TB manage, an essential step is to gain insight into the lineage of Mycobacterium tuberculosis (MTB) strains and the distribution of drug resistance. Although the Campania region is declared a cluster area for the infection, to contribute to the effort to understand TB evolution and transmission, still poorly known, we have generated a dataset of 159 genomes of MTB strains, from Campania region collected during 2018-2021, obtained from the analysis of whole genome sequence data. The results show that the most frequent MTB lineage is the 4 according for 129 strains (81.11%). Regarding drug resistance, 139 strains (87.4%) were classified as multi susceptible, while the remaining 20 (12.58%) showed drug resistance. Among the drug-resistance strains, 8 were isoniazid-resistant MTB (HR-MTB), 7 were resistant only to one antibiotic (3 were resistant only to ethambutol and 3 isolate to streptomycin while one isolate showed resistance to fluoroquinolones), 4 multidrug-resistant MTB, while only one was classified as pre-extensively drug-resistant MTB (pre-XDR). This dataset expands the existing available knowledge on drug resistance and evolution of MTB, contributing to further TB-related genomics studies to improve the management of TB infection.
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. Mice were infected with Mtb and treatment with PZA was started at 28 days post-infection. At 42 days and 63 days post-infection, group of animals were euthanized and lung tissue was collected to isolate total RNA and used in microarray experiments. Mtb-infected, untreated animals served as controls.
Project description:The innate immune system provides the first response to pathogen infection and orchestrates the activation of the adaptive immune system. Though a large component of the innate immune response is common to all infections, pathogen-specific innate immune responses have been documented as well. The innate immune response is thought to be especially critical for fighting infection with Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis (TB). While TB can be a deadly disease, only 5-10% of individuals infected with MTB develop active disease, and this inter-individual variation is, at least partly, heritable. Studies of inter-individual variation in the innate immune response to MTB infection may therefore shed light on the genetic basis for variation in susceptibility to TB. Yet, to date, we still do not know which properties of the innate immune response are specific to MTB infection and which represent a general response to pathogen infection. To begin addressing this gap, we infected macrophages with eight different bacterial pathogens, including different MTB strains and related mycobacteria, and studied the transcriptional response to infection. We found that although the gene expression changes were largely consistent across the bacterial infection treatments, we were able to identify a novel subset of genes whose regulation was affected specifically by infection with mycobacteria. Genetic variants that are associated with regulatory differences in these genes should be considered candidate loci for explaining inter-individual susceptibility TB. RNA-seq of monocyte-derived macrophages isolated from 6 healthy European males at 4, 18, and 48 hours post-infection with the following 8 bacteria: Mycobacterium tuberculosis (MTB) H37Rv, Mycobacterium tuberculosis GC1237, MTB GC1237, bacillus Calmette-Guérin (BCG), Mycobacterium smegmatis, Yersinia pseudotuberculosis, Salmonella typhimurium, and Staphylococcus epidermidis. table-s1.txt is a tab-delimited text file that contains the batch-corrected log2 counts per million for each of the 156 samples, as well as the Ensembl gene ID and gene name. BCG = bacillus Calmette-Guérin GC = Mycobacterium tuberculosis GC1237 Rv = Mycobacterium tuberculosis (MTB) H37Rv Rv+ = heat-inactivated MTB H37Rv Salm = Salmonella typhimurium Smeg = Mycobacterium smegmatis Staph = Staphylococcus epidermidis Yers = Yersinia pseudotuberculosis
Project description:Tuberculosis (TB) is a heterogeneous disease manifesting in a subset of individuals infected with aerosolized Mycobacterium tuberculosis (Mtb). Unlike human TB, murine infection results in uniformly high lung bacterial burdens and poorly organized granulomas. To develop a TB model that more closely resembles human disease, we infected mice with an ultra-low dose (ULD) of between 1-3 founding bacteria, reflecting a physiologic inoculum. ULD-infected mice exhibited highly heterogeneous bacterial burdens, well-circumscribed granulomas that shared features with human granulomas, and prolonged Mtb containment with unilateral pulmonary infection in some mice. We identified blood RNA signatures in mice infected with an ULD or a conventional Mtb dose (50-100 CFU) that correlated with lung bacterial burdens and predicted Mtb infection outcomes across species, including risk of progression to active TB in humans. Overall, these findings highlight the potential of the mouse TB model and show that ULD infection recapitulates key features of human TB.
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:Mycobacterium tuberculosis (Mtb) antigen-specific cellular response is promising for detectionof Mtb infection, but not efficient for diagnosis of TB. We firstly identified 16 TB disease-specific protein markers measured in the culture supernatant of Mtb-stimulated whole blood using a 640 human proteins array, the highest throughput antibody-based protein array available at the time when we did this study. Potential TB-related proteins were then analyzed across three different patient cohorts comprised of healthy controls, LTBI, non-TB pneumonia, and TB patients to evaluate how the biomarkers performed in diagnosing TB in the real clinical setting. The data finally reveal an eight-protein biosignature of TB.
Project description:Mycobacterium tuberculosis (Mtb) antigen-specific cellular response is promising for detectionof Mtb infection, but not efficient for diagnosis of TB. We firstly identified 16 TB disease-specific protein markers measured in the culture supernatant of Mtb-stimulated whole blood using a 640 human proteins array, the highest throughput antibody-based protein array available at the time when we did this study. Potential TB-related proteins were then analyzed across three different patient cohorts comprised of healthy controls, LTBI, non-TB pneumonia, and TB patients to evaluate how the biomarkers performed in diagnosing TB in the real clinical setting. The data finally reveal an eight-protein biosignature of TB.
Project description:Tuberculosis (TB) is a contagious disease that is a primary cause of mortality and illness in around a quater of the world' population particular in low income nations. The disease most commonly affects lung, but pathogens can also be found in other parts of the body. Mycobacterium tuberculosis (Mtb) is the etiologic agent of TB and its ability to penetrate immune cells and develop a niche by beating the host's defense mechanism is crucial to its pathogenic sucess. Mtb has a diverse lipid and protein spectrum. Understanding the host-pathogen-interplay in active TB will have a substantial impact in understanding molecular mechanisms of Mtb infection and guide the development of vaccination, diagnostics and therapy response monitoring.
Project description:Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), latently infects one quarter of the world’s population. The rise of multidrug resistant (MDR) Mtb infections worldwide presents a significant obstacle to curb TB globally. While human studies report dysregulated immune responses in MDR TB patients, there is a lack of clear understanding of the host-pathogen interactions following MDR Mtb infection. We recently showed that Mtb carrying a rifampicin drug resistance (RDR)-conferring single nucleotide polymorphism in the RNA polymerase-B gene (Mtb rpoB-H445Y) can modulate host macrophage metabolic reprogramming by production of Type I IFNs. Here, using a mouse model, we have characterized the host immune response in vivo following RDR Mtb infection. We show that despite establishment of Mtb infection in the lung and dissemination to the peripheral organs, lung myeloid and lymphoid immune responses to RDR Mtb is suppressed through a Type I IFN-dependent mechanism. These results coincide with a muted responses in the bone marrow hematopoietic stem and progenitor cells (HSPCs) and progenitors following RDR Mtb infection. These results suggest that host directed therapeutics and vaccines for drug resistant TB may need to be target specific host immune pathways for protection.
Project description:The critical role of type I IFN (IFN I ) in viral disease is thoroughly documented while their function in bacterial infection remains ambiguous. General interest in biological functions of IFN I in Mycobacterium tuberculosis (Mtb) infection was raised by the identification of a distinct IFN I gene expression signature in tuberculosis (TB) patients. Here we demonstrate that TB-susceptible mice lacking the receptor for IFN I (IFNAR1) were protected from death upon aerogenic infection with Mtb. Increased survival was accompanied by reduced bacterial burden and ameliorated lung pathology as well as diminished production of proinflammatory IL-1?, among other cytokines. IFNAR1 signaling did not affect T cell responses, but markedly altered migration of inflammatory monocytes and neutrophils to the lung during pulmonary TB. This process was orchestrated by presence of IFNAR1 in both immune and tissue-resident radioresistant cells. IFNAR1-driven TB susceptibility was initiated by CXCL5/CXCL1-driven accumulation of neutrophils into alveoli and subsequently a distinct compartmentalization of Mtb in lung phagocytes. We conclude that IFN I alters early innate events at the site of Mtb invasion leading to unleashed inflammation. Hence, our data furnish a mechanistic explanation for the detrimental role of IFN I in pulmonary TB. dual-color color-swap