Project description:Mycobacterium tuberculosis (MTB) infects and replicates in lung mononuclear phagocytes (MNPs) with astounding ability to evade elimination. A virulence determinant that contributes to MTB’s ability to survive within MNPs is ESX-1, a type VII secretion system. However, how MTB virulence factors influence mononuclear cell recruitment and/or differentiation remains unknown. Here, using single-cell RNA sequencing, we studied the role of ESX-1 in MNP heterogenicity and response in mice and murine bone marrow-derived macrophages. We found that ESX-1 is required for MTB to recruit diverse MNP subsets with high MTB burden. Further, MTB induces an anti-inflammatory signature that may lead to more permissive MNPs. Spatial transcriptomics revealed an upregulation of anti-inflammatory signals in MTB lesions, where monocyte-derived macrophages concentrate near MTB-infected cells. Together, our findings suggest that MTB ESX-1 mediates the recruitment and differentiation of anti-inflammatory MNPs, which MTB can infect and manipulate for survival.
Project description:Mycobacterium tuberculosis (MTB) infects and replicates in lung mononuclear phagocytes (MNPs) with astounding ability to evade elimination. A virulence determinant that contributes to MTB’s ability to survive within MNPs is ESX-1, a type VII secretion system. However, how MTB virulence factors influence mononuclear cell recruitment and/or differentiation remains unknown. Here, using single-cell RNA sequencing, we studied the role of ESX-1 in MNP heterogenicity and response in mice and murine bone marrow-derived macrophages. We found that ESX-1 is required for MTB to recruit diverse MNP subsets with high MTB burden. Further, MTB induces an anti-inflammatory signature that may lead to more permissive MNPs. Spatial transcriptomics revealed an upregulation of anti-inflammatory signals in MTB lesions, where monocyte-derived macrophages concentrate near MTB-infected cells. Together, our findings suggest that MTB ESX-1 mediates the recruitment and differentiation of anti-inflammatory MNPs, which MTB can infect and manipulate for survival.
Project description:Mycobacterium tuberculosis (MTB) infects and replicates in lung mononuclear phagocytes (MNPs) with astounding ability to evade elimination. A virulence determinant that contributes to MTB’s ability to survive within MNPs is ESX-1, a type VII secretion system. However, how MTB virulence factors influence mononuclear cell recruitment and/or differentiation remains unknown. Here, using single-cell RNA sequencing, we studied the role of ESX-1 in MNP heterogenicity and response in mice and murine bone marrow-derived macrophages. We found that ESX-1 is required for MTB to recruit diverse MNP subsets with high MTB burden. Further, MTB induces an anti-inflammatory signature that may lead to more permissive MNPs. Spatial transcriptomics revealed an upregulation of anti-inflammatory signals in MTB lesions, where monocyte-derived macrophages concentrate near MTB-infected cells. Together, our findings suggest that MTB ESX-1 mediates the recruitment and differentiation of anti-inflammatory MNPs, which MTB can infect and manipulate for survival.
Project description:The virulence of Mycobacterium tuberculosis (Mtb), either as mostly aggregates or single cells (Mtb-SC), was compared using a rabbit model of pulmonary infection. Our hypothesis is that aggregation contributes to enhanced virulence of Mtb. Rabbit lung transcriptome was analyzed by RNAseq to identify differentially regulated gene networks and pathways between Mtb-AG and Mtb-SC infection of rabbit lungs soon after seeding of the bacteria (24 hours post-inoculation).
Project description:Virulence effectors secreted by Mycobacterium tuberculosis (Mtb) help subvert host immune mechanisms and, therefore, are critical for establishing infection and pathogenesis. However, knowledge in terms of signaling mechanisms that modulate the secretion of virulence factors is sparse. We performed high-throughput secretome, phosphoproteome, and phospho-secretome analysis of Mtb. We combined the analysis with empirical validations to show regulation of mycobacterial secretion through protein phosphorylation. System level PPI network analysis superimposed with the secretome, phosphoproteome, and phospho-secretome profile revealed an intricate relationship between phosphorylation and secretion. At the core of the network was a key virulence factor CFP10. We identified PknA to be the kinase responsible for phosphorylating CFP10. Using genetic tools, we show that phosphomimetic mutation of CFP10 negatively regulates the secretion of virulence mediator ESAT6. Significantly, the dynamics of CFP10 phosphorylation strongly influenced bacterial virulence and survival within macrophages and mice. Together, the results show that the dynamic phosphorylation status of the secretory protein CFP10 regulates the secretion of virulence factors and impacts virulence.
Project description:Mycobacterium tuberculosis (Mtb) has co-evolved with humans for thousands of years leading to variation in clinical virulence, transmissibility, and disease phenotypes. To identify bacterial contributors to this phenotypic diversity, we developed new RNA-seq and phylogenomic analysis tools to capture hundreds of Mtb isolate transcriptomes, link transcriptional variation to genetic variation, and find associations between variants and epidemiologic traits. Across 274 Mtb clinical isolates, we uncovered unexpected diversity in expression of virulence genes which could be linked to known and previously unrecognized regulators. Surprisingly, we found that many isolates harbor variants associated with decreased expression of EsxA (Esat6) and EsxB (Cfp10), which are virulence effectors, dominant T cell antigens, and immunodiagnostic targets. Across >55,000 isolates, these variants associate with increased transmissibility, especially in drug resistant Mtb strains. Our data suggest expression of key Mtb virulence genes is evolving across isolates in part to optimize fitness under drug pressure, with sobering implications for immunodiagnostics and next-generation vaccines.
Project description:Mycobacterium tuberculosis (Mtb) has co-evolved with humans for thousands of years leading to variation in clinical virulence, transmissibility, and disease phenotypes. To identify bacterial contributors to this phenotypic diversity, we developed new RNA-seq and phylogenomic analysis tools to capture hundreds of Mtb isolate transcriptomes, link transcriptional variation to genetic variation, and find associations between variants and epidemiologic traits. Across 274 Mtb clinical isolates, we uncovered unexpected diversity in expression of virulence genes which could be linked to known and previously unrecognized regulators. Surprisingly, we found that many isolates harbor variants associated with decreased expression of EsxA (Esat6) and EsxB (Cfp10), which are virulence effectors, dominant T cell antigens, and immunodiagnostic targets. Across >55,000 isolates, these variants associate with increased transmissibility, especially in drug resistant Mtb strains. Our data suggest expression of key Mtb virulence genes is evolving across isolates in part to optimize fitness under drug pressure, with sobering implications for immunodiagnostics and next-generation vaccines.
Project description:Mycobacterium tuberculosis (Mtb) is well adapted to survive in macrophages and usually subverts the bactericidal mechanisms of these professional phagocytes. The adaptation of Mtb to the intracellular life depends on its ability to regulate the expression of its genes. Among the most important bacterial transcription activators are the sigma factors that bind to the RNA polymerase and give it promotor specificity. Sigma factor E (SigE) controls the expression of genes that are essential for Mtb virulence. Analysis of the macrophage transcriptional response indicated that proteins encoded by the sigE regulon are involved in the modulation of the macrophage inflammatory response. We compared the global gene expression of THP1 macrophages infected with H37Rv and SigE to the gene expression profile of uninfected macrophages.
Project description:Mycobacterium tuberculosis (Mtb) is well adapted to survive in macrophages and usually subverts the bactericidal mechanisms of these professional phagocytes. The adaptation of Mtb to the intracellular life depends on its ability to regulate the expression of its genes. Among the most important bacterial transcription activators are the sigma factors that bind to the RNA polymerase and give it promotor specificity. Sigma factor E (SigE) controls the expression of genes that are essential for Mtb virulence. Analysis of the macrophage transcriptional response indicated that proteins encoded by the sigE regulon are involved in the modulation of the macrophage inflammatory response. We compared the global gene expression of mouse bone marrow macrofages infected with H37Rv and SigE to the gene expression profile of the uninfected macrophages.
Project description:Mycobacterium tuberculosis (Mtb) is well adapted to survive in macrophages and usually subverts the bactericidal mechanisms of these professional phagocytes. The adaptation of Mtb to the intracellular life depends on its ability to regulate the expression of its genes. Among the most important bacterial transcription activators are the sigma factors that bind to the RNA polymerase and give it promotor specificity. Sigma factor E (SigE) controls the expression of genes that are essential for Mtb virulence. Analysis of the macrophage transcriptional response indicated that proteins encoded by the sigE regulon are involved in the modulation of the macrophage inflammatory response. Keywords: Comparison of responses to infections