Tuberculosis

We successfully employed a single cell RNA sequencing (scRNA-seq) approach to describe the cells and the communication networks characterizing granulomatous lymph nodes of TB patients. When mapping cells from individual patient samples, clustered based on their transcriptome similarities, we uniformly identify several cell types that known to characterize human and non-human primate granulomas. Whether high or low Mtb burden, we find the T cell cluster to be one of the most abundant. Many cells expressing T cell markers are clearly quantifiable within this CD3 expressing cluster. Other cell clusters that are uniformly detected, but that vary dramatically in abundance amongst the individual patient samples, are the B cell, plasma cell and macrophage/dendrocyte and NK cell clusters. When we combine all our scRNA-seq data from our current 23 patients (in order to add power to cell cluster identification in patient samples with fewer cells), we distinguish T, macrophage, dendrocyte and plasma cell subclusters, each with distinct signaling activities. The sizes of these subclusters also varies dramatically amongst the individual patients. In comparing FNA composition we noted trends in which T cell populations and macrophage/dendrocyte populations were negatively correlated with NK cell populations. In addition, we also discovered that the scRNA-seq pipeline, designed for quantification of human cell mRNA, also detects Mtb RNA transcripts and associates them with their host cells transcriptome, thus identifying individual infected cells. We hypothesize that the number of detected bacterial transcript reads provides a measure of Mtb burden, as does the number of Mtb-infected cells. The number of infected cells also varies dramatically in abundance amongst the patient samples. CellChat analysis identified predominating signaling pathways amongst the cells comprising the various granulomas, including many interactions between stromal or endothelial cells and the other component cells, such as Collagen, FN1 and Laminin. In addition, other more selective communications pathways, including MIF, MHC-1, MHC-2, APP, CD 22, CD45, and others, are identified as originating or being received by individual immune cell components. Author SummaryThe research conducted describes the cellular composition and communication networks within granulomatous lymph nodes of tuberculosis (TB) patients, employing a single-cell RNA sequencing (scRNA-seq) approach. By analyzing individual patient samples and clustering cells based on their transcriptome similarities, the study reveals several consistent cell types described to be present in both human and non-human primate granulomas. Notably, T cell clusters emerge as abundant in most samples. Additionally, variations in the abundance of B cells, plasma cells, macrophages/dendrocytes, and NK cells among patient samples are observed. Pooling scRNA-seq data from 23 patients enabled the identification of T, macrophage, dendrocyte, and plasma cell subclusters, each displaying distinct signaling activities. Moreover, the study uncovers a surprising capability of the scRNA-seq pipeline to detect Mtb RNA transcripts within host cells, providing insights into individual infected cells and Mtb burden. CellChat analysis unveils predominant signaling pathways within granulomas, highlighting interactions between stromal/endothelial cells and other immune cell components. Moreover, selective communication pathways involving molecules such as Collagen, FN1, Laminin, CD99, MIF, MHC-1, APP and CD45 are identified, shedding light on the intricate interplay within granulomatous lymph nodes during TB infection.

Pulmonary infections caused by the group of nontuberculosis mycobacteria (NTM), Mycobacterium avium complex (MAC), are increasing worldwide and a growing public health concern. Pulmonary granulomas are the hallmark of MAC lung infection, yet reliable correlates of granuloma progression and susceptibility in immunocompetent hosts are poorly defined. The development of mouse models that recapitulate the diversity of granulomas seen in MAC pulmonary disease in humans is crucial to study mechanisms of susceptibility in humans and for preclinical evaluation of therapeutics. Unlike widely used inbred mouse strains, mice that carry the mutant allele at the genetic locus sst1 develop human-like pulmonary tuberculosis featuring well-organized caseating granulomas. These mice became instrumental in pre-clinical testing of novel interventions. In this study we tested whether the B6.Sst1S that carries the sst1 mutant allele on standard B6 background develop more advanced pulmonary infection with NTM M. avium spp. hominissuis (M.av). To assess pulmonary disease progression, we utilized traditional semi-quantitative histomorphological evaluation and fluorescent multiplex immunohistochemistry (fmIHC) in combination with whole slide imaging and digital image analysis. After infection with the laboratory M.av strain 101, the B6.Sst1S pulmonary lesions progressed 12 - 20 weeks post infection, although we did not observe the formation of necrotic granulomas during this interval. Using fmIHC, we determined that the disease progression was associated with a steadily increasing proportion of mycobacteria infected Arg1+ and double positive iNOS+/Arg1+ macrophages. The B6.Sst1S granulomas had a greater proportion of Arg1+ and double positive iNOS+/Arg1+ macrophages, and decreased T cell density, as compared to wild type B6 mice. Thus, the genetic composition of the B6.Sst1S mice renders them more susceptible to pulmonary M.av infection. In combination with more virulent clinical isolates of M.av these mice could provide an improved mouse model that recapitulates more severe pulmonary disease in humans. The Arg1 macrophage expression in this model combined with automated fmIHC could serve as a sensitive biomarker for the unbiased assessment of medical countermeasures against NTM infection.

Tuberculosis and non-tuberculous mycobacterial (NTM) diseases are infections caused by Mycobacterium tuberculosis and non-tuberculous mycobacteria such as the Mycobacterium avium complex, leading to the formation of granulomatous lesions with caseous necrosis in the lungs. Although granulomatous tissues are infiltrated by numerous inflammatory cells, including macrophages, lymphocytes, and neutrophils, the mechanisms underlying granuloma formation caused by mycobacteria remain unclear. In this study, we performed single-cell spatial analysis on lung tissue samples from patients with tuberculosis and NTM diseases to investigate the infiltrating cell populations. We analyzed seven lung lesions and identified individual cell types infiltrating the granulomatous tissue. Based on gene expression profiles, at least four macrophage subtypes were identified. Notably, SPP1-positive macrophages predominantly found infiltrating the granulomatous tissue. Langhans giant cells expressed SPP1, and numerous SPP1-positive macrophages without giant cell morphology were also observed around the granulomas. RNA-seq analysis revealed elevated SPP1 expression in mycobacterium-infected tissues. The SPP1-CD44 signaling pathway was active in SPP1-positive macrophages and their neighboring cells in mycobacterium-infected tissues. SPP1-positive macrophages were also observed around granulomas in other granulomatous diseases, such as granulomatosis with polyangiitis and sarcoidosis. These findings suggest that SPP1-CD44 signaling in SPP1-positive macrophages may play a role in the pathology of granulomatous diseases, including mycobacterial infections. Brief summarySPP1-CD44 signaling in SPP1-positive macrophages may play a role in granuloma formation in mycobacterial and other granulomatous diseases.

BackgroundClinical manifestations of tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) show lineage-specific differences contributed by genetic polymorphism such as phylo-single nucleotide variations (PhyloSNPs) and insertion or deletions (INDELs). Intragenomic rearrangement events, such as gene duplications and deletions, may cause gene copy number differences in Mtb, contributing to lineage-specific phenotypic variations, if any, which need better understanding. ResultsThe relative gene copy number differences in high-quality publicly available whole genome sequencing datasets of 9,482 clinical Mtb isolates were determined by repurposing and modifying an RNA-seq data analysis pipeline. The pipeline included various steps, viz., alignment of reads, sorting by coordinate, GC bias correction, and variant stabilising transformation. The strategy showed maximum separation of lineage-specific clusters in two principal components, capturing [~]54% variability. Unsupervised hierarchical clustering of the top 100 genes and pairwise comparisons between Mtb lineages revealed an overlapping subset of genes (n=42) having significantly perturbed copy numbers (Benjamin Hochberg adjusted P-value < 0.05 and log2(drug-resistant/sensitive) > {+/-} 1). These 42 genes formed multiple tandem gene clusters and are known to be involved in virulence, pathogenicity and defence response to invading phages. A separate comparison showed a significantly high copy number of phage genes and a recently reported druggable target Rv1525 in pre- and extensively drug-resistant (Pre-XDR, XDR) compared to drug-sensitive clinical Mtb isolates. ConclusionThe identified gene sets in Mtb clinical isolates may be useful targets for lineage-specific therapeutics and diagnostics development.

Multidrug-resistant tuberculosis (mdrtb) refers to TB infection resistant to at least two most powerful anti-TB drugs, isoniazid and rifampincin. It has been estimated that globally 3.5% (which can be much higher in some regions) of newly diagnosed TB patients, and 20.5% of previously treated patients had mdrtb. Extensively drug-resistant TB (xdrtb) has resistance to rifampin and isoniazid, as well as to any member of the quinolone family and at least one of the second line injectable drugs: kanamycin, amikacin and capreomycin. xdrtb accounts for 4-20% of mdrtb. Early detection and targeted treatment are priorities for mdrtb/xdrtb control. The suspicion of mdr/xdr -pulmonary TB (mdrptb or xdrptb) by chest imaging shall suggest intensive diagnostic testing for mdrptb/xdrptb. We hypothesize that multiple nodular consolidation (NC) may serve one of the differentiators for separating dsptb vs mdrptb/xdrptb cases. For this study, mdrptb cases (n=310) and XDR-PTB cases ([xcap]=I58) were from the NIAID TB Portals Program (TBPP) <https://tbportals.niaid.nih.gov>. Drug sensitive pulmonary TB (dsptb) cases were from the TBPP collection (n=112) as well as the Shenzhen Center for Chronic Disease Control (n=111), Shenzhen, China, and we excluded patients with HIV(+) status. Our study shows NC, particularly multiple NCs, is more common in mdrptb than in dsptb, and more common in xdrptb than in mdrptb. For example, 2.24% of dsptb patients, 13.23% of mdrptb patients, and 20.89% of xdrptb patients, respectively, have NCs with diameter >= 10mm equal or more than 2 in number.

BackgroundThe immune response to Mycobacterium tuberculosis (M. tuberculosis) is central to the pathogenesis of tuberculosis (TB), yet the immune dynamics induced by drug-resistant strains remain underexplored. Understanding the hosts immune response to both drug-sensitive and drug-resistant M. tuberculosis isolates is crucial for elucidating the mechanisms of pathogenesis and resistance. This study aims to assess the cellular immune responses, including PBMC proliferation, cytokine secretion (IL-4 and IL-17a), and reactive oxygen species (ROS) production in response to live drug-sensitive and drug-resistant M. tuberculosis clinical isolates. MethodsPeripheral blood mononuclear cells (PBMCs) from PPD-negative and PPD-positive healthy volunteers were stimulated with live M. tuberculosis isolates, including MDR, SI-resistant, and sensitive strains. The immune responses were assessed by evaluating cell proliferation, secretion of IL-4 and IL-17a cytokines, and ROS production over a 9-day period. ResultsPBMCs from PPD-positive individuals exhibited a higher proliferative response compared to PPD-negative individuals, indicating more robust immune memory. IL-4 secretion was low but varied among samples, with higher levels observed in response to MDR isolates, suggesting a potential role in immunopathology. IL-17a levels increased over time, particularly in PPD-positive individuals, and MDR strains elicited a stronger response than sensitive isolates. ROS production was significantly elevated in response to resistant strains, reflecting the hosts oxidative defense mechanisms. ConclusionThis study demonstrates distinct immune responses to drug-resistant M. tuberculosis isolates, with variations in cell proliferation, cytokine secretion, and ROS production. These findings provide insights into the immune dynamics during infection with resistant strains and underscore the importance of genotype-environment interactions in TB pathogenesis. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/626310v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1bb9ad6org.highwire.dtl.DTLVardef@1b268e7org.highwire.dtl.DTLVardef@52800org.highwire.dtl.DTLVardef@85234b_HPS_FORMAT_FIGEXP M_FIG C_FIG

IntroductionTuberculosis (TB) is the leading cause of morbidity and mortality globally, responsible for an estimated annual 10.0 million new cases and 1.3 million deaths among infectious diseases with Africa contributing a quarter of these cases in 2019. Classification of Mycobacterium tuberculosis (MTB) strains is important in understanding their geographical predominance and pathogenicity. Different studies have gone ahead to classify MTB using different methods. Some of these include; RFLP, spoligotyping, MIRU-VNTR and SNP set based phylogeny. The SNP set based classification has been found to be in concordance with the region of difference (RD) analysis of MTB complex classification system. In Uganda, the most common cause of pulmonary tuberculosis (PTB) is Uganda genotype of MTB and accounts for up to 70 % of isolates. MethodsSequenced MTB genome samples were retrieved from NCBI and others from local sequencing projects. The genomes were subjected to snippy (a rapid haploid variant calling and core genome alignment) to call variants and annotate them. Outputs from snippy were used to classify the isolates into Uganda genotypes and Non Ugandan genotypes based on 62 SNP set. The Ugandan genotype isolates were later subjected to 413 SNP set and then to a pan genome wide association analysis. Results6 Uganda genotype isolates were found not to classify as either Uganda I or II genotypes based on the 62 SNP set. Using the 413 SNP set, the 6 Uganda genotype isolates were found to have only one SNP out of the 7 SNPs that classify the Uganda I genotypes. They were also found to have both missense and frameshift mutations within the ctpH gene whereas the rest of Uganda I that had a mutation within this gene, was a missense. ConclusionAmong the Uganda genotypes genomes, Uganda I genomes are unstable. We used publicly available datasets to perform analysis like mapping, variant calling, mixed infection, pan-genome analysis to investigate and compare evolution of the Ugandan genotype.

Mycobacterium tuberculosis (Mtb) causes the majority of reported cases of human tuberculosis (TB), one of the deadliest infectious diseases worldwide. New diagnostic tools and approaches to detect drug-resistance must be introduced by 2025 to achieve the End-TB Strategy goals set for 2030 by the WHO. Genomic epidemiology of TB has allowed the expansion of catalogs listing genetic signatures of Mtb drug-resistance. However, very few Mtb strains from Latin America have participate in previous genomic epidemiologic efforts. Here we present the first functional genomic epidemiology study of drug-resistant Mtb strains in Mexico, incorporating the genomic characterization of 133 genomes, including 53 newly sequenced isolates, to provide a comprehensive phylogeographic analysis of drug resistant Mtb in Mexico. The study evidences the prevalence of Euro-American Lineage L4 (96.2%), featuring a uniform distribution of the sublineages X-type (33.08%), LAM (22.56%), and Haarlem (21.05%). Our results demonstrate low levels of agreement with traditional drug sensitivity tests (DST), raising concerns for drug-resistant isolates lacking any previously reported genetic signatures of resistance. Finally, we propose a novel functional networking tool (FuN-TB) to explore metabolic and cellular signatures of drug resistance. Applying functional genomics approaches to Latin American Mtb genomes will provide new drug-resistance screening targets that can contribute to bed side decision-making and advise local public policy. Abstract importanceWe presented the first phylogeographic analysis of Mycobacterium tuberculosis (Mtb) of Mexico. Our analysis integrates 133 genome sequences and is focused on the identification of genetic signatures associated to drug-resistance. The results show the geographic distribution of sublineages and drug-resistance phenotypic classes. Additionally, we propose a novel functional networking tool (FuN-TB) to explore metabolic and cellular signatures of drug resistance associated. We show for the first time that Mtb isolates from Mexico encode for region-specific genetic signarures of antimicrobial resistance. Applying functional genomics approaches to Latin American Mtb genomes will provide new drug-resistance screening targets that can contribute to bed side decision-making and advise local public policy.

Tuberculosis (TB) remains a major global health challenge, particularly in the context of multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb). Host-directed therapies (HDTs) have been proposed as adjunctive therapy to enhance immune control of infection. Recently, one such HDT, pharmacologic modulation of myeloid-derived suppressor cells (MDSCs), has been proposed to treat MDR-TB. While MDSCs have been well characterized in cancer, their role in TB pathogenesis remains unclear. To investigate whether MDSCs or other myeloid suppressor populations contribute to TB granuloma microenvironments (GME), we performed spatial transcriptional profiling and single-cell immunophenotyping on eighty-four granulomas in lung specimens from three individuals with active disease. Granulomas were histologically classified based on H&E staining, and transcriptional signatures were compared across regions of interest (ROIs) at different states of granuloma maturation. Our analysis revealed that immune suppression within granuloma was not primarily driven by classical MDSCs but rather by multiple myeloid cell subsets, including dendritic cells expressing indoleamine 2,3 dioxygenase-1 expressing (IDO1+ DCs). IDO1+ DCs were the most frequently observed suppressive myeloid cells, particularly in cellular regions, and their spatial proximity to activated T cells suggested localized immunosuppression. Importantly, granulomas at different stages contained distinct proportions of suppressor myeloid cells, with necrotic and cellular regions showing different myeloid phenotypes that may influence granuloma progression. Gene set enrichment analysis (GSEA) further indicated that elevated IDO1 expression was associated with a complex immune response that balanced suppressive signaling, immune activation, and cellular metabolism. These findings suggest that classical MDSCs, as defined in tumor microenvironments, likely play a minor role in TB, whereas IDO1+ DCs may be key regulators of immune suppression in granulomas influencing local Mtb control in infected lung. A deeper understanding of the role of IDO1+ suppressive myeloid cells in TB granulomas is essential to assessing their potential as therapeutic targets in TB treatment.

Toxin-antitoxin (TA) modules are one of the prominent determinants that triggers a persistent state aiding Mycobacterium tuberculosis evasion to host generated stresses. The 79 characterized and putative TA systems described in M. tuberculosis are dominated by the VapBC, MazEF, HigAB, RelBE and ParDE TA families, largely involved in persistence and cell arrest. Hence, there is a need to maintain and conserve the TA loci in the chromosome of the pathogen. It is essential to study the genomic differences of the TA systems in clinical isolates along with its association to drug susceptibility patterns and lineage. In the current study, the TA loci and their promoter sequences were analysed from the whole genome sequence data of 74 clinical isolates. Mykrobe Predictor was used for lineage identification and drug resistance predictions in the clinical isolates. Polymorphisms associated with 79.8% (63/79) TA systems were observed across 72 clinical isolates. Among the TA systems, the isolates had a varying number of polymorphisms localised primarily in the toxin genes (58.7%), antitoxin genes (40.7%) and chaperones (0.6%), due to Single Nucleotide Polymorphism (SNP) resulting in transition (67.3%), transversion or frameshift mutations. Our analysis suggests the presence of novel Phylo-SNPs by establishing high confidence association of specific lineages to polymorphisms in the TA systems. Notably, association of polymorphisms in Rv1838c-1839c (VapBC13), Rv3358-3357 (YefM/YoeB) and Rv0240-0239 (VapBC24) to Delhi/Central Asia lineage. The polymorphic loci of the 3 TA systems is localised in the antitoxin gene of the Delhi/Central Asia strains, with a resultant silent mutation. The assessment of correlation between TA polymorphisms and the drug resistance profile revealed correlation of SNPs in VapBC35 with drug resistant M. tuberculosis strains and SNPs in VapBC24, VapBC13 and YefM/YoeB to drug sensitive strains.

BackgroundTuberculosis (TB) is the leading cause of infectious disease mortality worldwide. Numerous blood-based gene expression signatures have been proposed in the literature as alternative tools for diagnosing TB infection. Ongoing efforts are actively focused on developing additional signatures in other TB-related contexts. However, the generalizability of these signatures to different patient contexts is not well-characterized. There is a pressing need for a well-curated database of TB gene expression studies for the systematic assessment of existing and newly developed TB gene signatures. ResultsWe built the curatedTBData, a manually-curated database of 49 TB transcriptomic studies. This data resource is freely available through GitHub and as an R Bioconductor package that allows users to validate new and existing biomarkers without the challenges of harmonizing heterogeneous studies. We also demonstrate the use of this data resource with cross-study comparisons for 72 TB gene signatures. For the comparison of subjects with active TB from healthy controls, 19 gene signatures had weighted mean AUC of 0.90 or greater, with the highest result of 0.94. In active TB disease versus latent TB infection, 7 gene signatures had weighted mean AUC of 0.90 or greater, with a maximum of 0.93. We also explore ensembling methods for averaging predictions from multiple gene signatures to significantly improve diagnostic ability beyond any single signature. ConclusionsThe curatedTBData data package offers a comprehensive resource of curated gene expression and clinically annotated data. It could be used to identify robust new TB gene signatures, to perform comparative analysis of existing TB gene signatures, and to develop alternative gene set scoring or ensembling methods, among other things. This resource will also facilitate the development of new signatures that are generalizable across cohorts or more applicable to specific subsets of patients (e.g. with rare comorbid conditions, etc.). We demonstrated that these blood-based gene signatures could distinguish patients with distinct TB outcomes; moreover, the combination of multiple gene signatures could improve the overall predictive accuracy in differentiating these subtypes, which point out an important aspect for the translation of genomics to clinical implementation.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is associated with clinical diversity and outcomes ranging from latent TB to active TB with distinct pathophysiologies. However, our understanding of the innate immune mechanisms related to the protection or progression of TB is limited. Among innate immune cells, the role of neutrophils is not fully elucidated, as they have been shown to exhibit both protective and harmful capacities in TB. This duality suggests possible differences in the nature and type of neutrophils present during the infection, generating different effects. We hypothesized that Mtb infection induces changes in neutrophil phenotype and function, influencing the infection outcomes. In order to decipher the link between neutrophils and disease progression, we used a cynomolgus macaque model of human TB. Based on clinical, bacteriological, and positron emission tomography with X-ray computed tomography (PET/CT) scan parameters, animals were stratified into two categories: animals that rapidly progressed to an active form of TB, designated as "fast progressors", and "slow progressors", which include low symptomatic or asymptomatic animals. In this study, we identified transcriptomic signatures of type I interferons and neutrophil degranulation in macaques with fast progression to active TB, which were not observed in animals with slow TB progression. Unsuppervised mass cytometry analysis showed the emergence of blood immature neutrophils (CD101+ CD10-) in fast progressing animals. In addition, circulating neutrophils from infected animals displayed capacities to modulate TNF- production and cytotoxic function of CD8 T cells in a contact-dependent mechanism. In the lungs, neutrophils infiltration in granuloma was higher in fast progressors and specifically located in the lymphocyte-rich region in lesions. These data suggest that specific neutrophil subpopulations are associated with disease progression. Furthermore, these data suggest that neutrophils may modulate CD8 T cells functions, which in turn contribute to the loss of Mtb control and fuel inflammation. AUTHORS SUMMARYMycobacterium tuberculosis (Mtb) infection in humans is associated with a wide range of disease progression, ranging from latent tuberculosis (TB) to active TB. Understanding immune factors leading to the control of the infection or disease progression is essential to identify new biomarkers and targets for host-directed therapies. Innate immunity plays an important role in inflammatory imbalance observed in active TB, among which neutrophils have both beneficial and detrimental roles. Using a macaque model developing a broad range of clinical forms of TB, we seek to understand the links between neutrophils and disease progression. We found that rapid progression to active TB leads to type I interferon signalling and neutrophil activation. In the blood, immature neutrophils were enriched when the disease progressed. In case of severe TB, Neutrophils also infiltrate a specific region of lung TB lesions rich in T lymphocytes, whereas they could modulate CD8 T cells. Our study provides new insights into the role of neutrophils in TB progression.

Mycobacterium tuberculosis complex (MTBC) consists of seven major lineages with three of them reported to circulate within West Africa: lineage 5 (West African 1) and lineage 6 (West African 2) which are geographically restricted to West Africa and lineage 4 (Euro-American lineage) which is found globally. It is unclear why the West African lineages are not found elsewhere; some hypotheses suggest that it could either be harboured by an animal reservoir which is restricted to West Africa, or strain preference for hosts of West African ethnicity, or inability to compete with other lineages in other locations. We tested the hypothesis that M. africanum (MAF) might have emigrated out of West Africa but was outcompeted by more virulent strains of M. tuberculosis (MTB). Whole genome sequences of MTB from Nigeria (n=21), China (n=21) and MAF from Mali (n=24) were retrieved, and a pan-genome analysis was performed after fully annotating these genomes. The outcome of this analysis shows that Lineages 4, 5 and 6 have relatively close pan-genomes whilst lineage 2 has an open pan-genome. We also see a correlation in numbers of some multiple copy core genes and amino acid substitution with lineage specificity that may have contributed to geographical distribution of these lineages. The findings in this study provides a perspective to one of the hypotheses that M. africanum might find it difficult to compete against the more modern lineages outside West Africa hence its localization to the geographical region.

Contrarily to other lineages such as L2 and L4, there are still scarce whole-genome-sequence data on L5-L6 MTBC clinical isolates in public genomes repositories. Recent results suggest a high complexity of L5 history in Africa. It is of importance for an adequate assessment of TB infection in Africa, that is still related to the presence of L5-L6 MTBC strains. This study reports a significant improvement of our knowledge of L5 diversity, phylogeographical history, and global population structure of Mycobacterium africanum L5. To achieve this aim, we sequenced new clinical isolates from Northern Nigeria and from proprietary collections, and used a new powerful bioinformatical pipeline, TB-Annotator that explores not only the shared SNPs but also shared missing genes, identical IS6110 insertion sites and shared regions of deletion. This study using both newly sequenced genomes and available public genomes allows to describe new L5 sublineages. We report that the MTBC L5 tree is made-up of at least 12 sublineages from which 6 are new descriptions. We confront our new classification to the most recent published one and suggest new naming for the discovered sublineages. Finally, we discuss the phylogeographical specificity of sublineages 5.1 and sublineage 5.2 and suggest a new hypothesis of L5-L6 emergence in Africa. Impact statementRecent studies on Mycobacterium africanum (L5-L6-L9 of MTBC) genomic diversity and its evolution in Africa discovered three new lineages of the Mycobacterium tuberculosis complex (MTBC) in the last ten years (L7, L8, L9). These discoveries are symptomatic of the delay in characterizing the diversity of the MTBC on the African continent. Another understudied part of MTBC diversity is the intra-lineage diversity of L5 and L6. This study unravels an hidden diversity of L5 in Africa and provides a more exhaustive description of specific genetic features of each sublineage by using a proprietary "TB-Annotator" pipeline. Furthermore, we identify different phylogeographical localization trends between L5.1 and L5.2, suggesting different histories. Our results suggest that a better understanding of the spatiotemporal dynamics of MTBC in Africa absolutely requires a large sampling effort and powerful tools to dig into the retrieved diversity. Data summary[A section describing all supporting external data, software or code, including the DOI(s) and/or accession numbers(s), and the associated URL. If no data was generated or reused in the research, please state this.] The search was done in the TB-Annotator 15901 genomes version which is available at: http://(to be added). The new sequenced genomes are available via NCBI Bioproject accession number: (to be added). The authors confirm all supporting data, code and protocols have been provided within the article or through supplementary data files.

RationaleMany blood-based transcriptional gene signatures for tuberculosis (TB) have been developed with potential use to diagnose disease, predict risk of progression from infection to disease, and monitor TB treatment outcomes. However, an unresolved issue is whether gene set enrichment analysis (GSEA) of the signature transcripts alone is sufficient for prediction and differentiation, or whether it is necessary to use the original statistical model created when the signature was derived. Intra-method comparison is complicated by the unavailability of original training data, missing details about the original trained model, and inadequate publicly-available software tools or source code implementing models. To facilitate these signatures replicability and appropriate utilization in TB research, comprehensive comparisons between gene set scoring methods with cross-data validation of original model implementations are needed. ObjectivesWe compared the performance of 19 TB gene signatures across 24 transcriptomic datasets using both re-rebuilt original models and gene set scoring methods to evaluate whether gene set scoring is a reasonable proxy to the performance of the original trained model. We have provided an open-access software implementation of the original models for all 19 signatures for future use. MethodsWe considered existing gene set scoring and machine learning methods, including ssGSEA, GSVA, PLAGE, Singscore, and Zscore, as alternative approaches to profile gene signature performance. The sample-size-weighted mean area under the curve (AUC) value was computed to measure each signatures performance across datasets. Correlation analysis and Wilcoxon paired tests were used to analyze the performance of enrichment methods with the original models. Measurement and Main ResultsFor many signatures, the predictions from gene set scoring methods were highly correlated and statistically equivalent to the results given by the original diagnostic models. PLAGE outperformed all other gene scoring methods. In some cases, PLAGE outperformed the original models when considering signatures weighted mean AUC values and the AUC results within individual studies. ConclusionGene set enrichment scoring of existing blood-based biomarker gene sets can distinguish patients with active TB disease from latent TB infection and other clinical conditions with equivalent or improved accuracy compared to the original methods and models. These data justify using gene set scoring methods of published TB gene signatures for predicting TB risk and treatment outcomes, especially when original models are difficult to apply or implement.

BackgroundBovine tuberculosis (bTB) is a chronic infectious disease primarily caused by Mycobacterium bovis, which inflicts significant economic losses on the global livestock industry worldwide and can also cause tuberculosis (TB) disease in other mammalian species, including humans. Alveolar macrophages are the host cells targeted by the pathogen during the early stages of infection. While they play a crucial role in controlling infection, the exact nature of the host-pathogen interaction and the genetic and epigenetic factors that modulate infection outcome remain poorly understood. ResultsHere, we used transcriptomics (RNA-seq) and chromatin configuration analyses (ChIP-seq and ATAC-seq) to examine the effects of intracellular mycobacterial infection on the bovine alveolar macrophage (bAM) transcriptome and epigenome. The primary focus was M. bovis infection, but we also conducted parallel comparative analyses using M. tuberculosis (the primary cause of human TB--hTB), M. bovis BCG (the vaccine strain), and gamma-irradiated (killed) M. bovis. Integration of RNA-seq, ChIP-seq, and ATAC-seq data revealed coordinated remodelling of chromatin accessibility and histone modification landscapes underpinning transcriptional activation of key immune and metabolic pathways in response to infection. The identification of candidate genes, including ERBB4, LRCH1, MRTFA, and RNPC3, through integrative analysis with a genome-wide association study (GWAS) for M. bovis infection susceptibility underscores the functional relevance of these regulatory networks. ConclusionsOur results demonstrate that M. bovis drives extensive reprogramming of the bAM epigenome, distinct from the responses elicited by other members of the M. tuberculosis complex (MTBC). The results of this multi-omics comparison provide new insights into the function of pivotal response genes and support the hypothesis that pathogen-driven epigenetic reprogramming of the bovine host macrophage is key to M. bovis survival. It also identifies molecular targets that may inform genome-enabled breeding strategies to enhance bTB disease resilience in cattle.

BackgroundTuberculosis (TB) is the second leading cause of death from an infectious disease worldwide. Mycobacterium tuberculosis complex (MTBC), the causative bacteria of TB, is becoming increasingly resistant to anti-TB drugs, resulting in poorer treatment outcomes. The mutations arising in MTBC strains during infection provide a record of bacterial diversification and adaptation, and indirect evidence on the selective pressures and conditions that MTBC encountered in vivo, such as those exerted by the immune system and antibiotic therapies. MethodsWe conducted a meta-analysis of MTBC sequenced strains with multiple clinical isolates sequenced from the same patient, from published studies and TB Portals. We applied stringent genomic QC criteria to keep only clonal isolates and applied robust genomic pipelines to identify mutations arising de novo during infection. A convergent evolution approach was applied to identify heavily mutated genes, operons, and candidate promoter across strains of multiple patients. We estimated the frequency of drug resistance acquisition during treatment for the subset of patients with available drug treatment data. ResultUsing 5,899 high-quality genomes from 1,056 TB patients after ensuring clonality of isolate genomes we identified limited within-host diversity was identified including 3,296 fixed mutations across 501 patients. A total of 21 genes, 25 operons and 27 promoter regions were statistically enriched by mutations compared to the rest of the genome, and additional loci with established or plausible adaptive roles approaching statistical significance. Significantly, this included multiple loci known to be involved in resistance to first-, second-, and last-line anti-TB drugs. Fluoroquinolone resistance was acquired more frequently during treatment than resistance to any other anti-TB drug. Previously reported candidate drug-resistance and -tolerance genes (prpR, Rv2571c, fadD11, helY, ndhA, Rv0139, fadE5, and mce1 operon) were also identified. Genes encoding regulators (phoR, whiB6 and mycP1) and effectors (espK and eccE1) of the virulence ESX-1 locus were frequently mutated in host. ConclusionsHere we analysed a large dataset of MTBC within-host genetic diversity. We show that frequently mutated genes in MTBC during infection reveal known and biologically plausible in host adaptations, predominantly associated drug resistance, but also in genes involved in pathogenesis. The higher resistance acquisition rate observed for fluoroquinolones may have important clinical relevance. We reveal a list of candidate loci which will require mechanistic characterisation and whose impact on disease progression will need to be investigated.

Limited reports have elucidated the role of one-carbon metabolism and its impact on the production of pro-inflammatory cytokines in tuberculosis (TB). In this study, analysis of the earlier reported scRNAseq data of alveolar macrophages (AMs) from the Mycobacterium tuberculosis (Mtb) H37Rv-infected C57BL/6 mice showed downregulation of phosphoglycerate dehydrogenase (PHGDH) and neutral amino acid transporter, i.e. Slc7a5. PHGDH is involved in the serine biosynthesis from the glycolytic node, and its downregulation in the AMs indicates that extracellular methionine mainly contributes carbon units for one-carbon metabolism. But lower expression of Slc7a5 reflects lower methionine uptake in macrophages in the Mtb-infected group. Global metabolome analysis of the Mtb-infected bone marrow-derived macrophages (BMDMs) showed a major biochemical shift at 24 hours post-infection (hpi) with perturbation of various nodes connected to the one-carbon metabolism, including serine-methionine metabolism and polyamine synthesis. A significantly low intracellular serine, methionine and polyamine levels with a high adenine, hypoxanthine, guanine and reduced-glutathione (GSH) levels indicated that the flux from one-carbon metabolism is diverted towards nucleotide salvage and glutathione production at 24 hpi in the Mtb-infected BMDMs. Proteome profiling of these Mtb-infected BMDMs indicated increased nucleotide salvage, glutathione production and a suppressed IL-1 response. This rewiring of the metabolic pathways suppressed the immune response and dampened the mycobacterial clearance. Further, methionine (1 mM) supplemented BMDMs upon Mtb infection showed improved cell viability with accelerated mycobacterial clearance by producing significantly higher IL-1{beta} levels. Methionine supplementation, to C57BL/6 mice, in drinking water for two weeks, helped in enhancing mycobacterial clearance in lungs, spleen and BMDMs by increasing pro-inflammatory response, especially by increasing IL-1{beta} and IFN-{gamma} production. Supplementation of methionine also increased Mtb-specific TNF--producing activated CD4+ cells in the spleen. So, methionine supplementation in macrophages and mice helped in mounting a better acute pro-inflammatory response, which could be used as a dietary supplementation strategy to improve clinical outcomes in TB. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/680834v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@362borg.highwire.dtl.DTLVardef@1e45fd3org.highwire.dtl.DTLVardef@4f2f3corg.highwire.dtl.DTLVardef@a61067_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIMycobacterium tuberculosis (Mtb) infection decreases methionine uptake and serine synthesis in primary macrophages. C_LIO_LIMethionine carbon units contribute to nucleotide salvage, and their restriction leads to lowered IL-1 response, which increases mycobacterial load. C_LIO_LIEx vivo methionine supplementation in the Mtb-infected macrophages increases pro-inflammatory response, leading to increased mycobacterial clearance. C_LIO_LIIn-vivo methionine supplementation improves pro-inflammatory response in lungs, spleen and bone marrow, leading to improved bacterial clearance upon Mtb-infection. C_LI

Current clinical tools for monitoring tuberculosis (TB) treatment response rely mostly on sputum culture and chest X-ray, which are unreliable in patients with low bacterial loads and lack the desirable promptness. There is a need for biomarkers able to provide earlier and more accurate insights into pathogen viability and response to therapy. We analyzed publicly available whole-blood RNA-seq data from 79 TB patients sampled at diagnosis, and weeks 1, 4, and 24 of standard anti-TB treatment. After aligning human reads and filtering, remaining reads were mapped to the Mycobacterium tuberculosis H37Rv genome to quantify rRNA subunit transcripts (16S, 23S, 5S, ITS1, ITS2). Microbiome profiles were assessed using Kraken2/Bracken, with alpha/beta diversity analyses and differential abundance (ANCOM-BC2). 16S and 23S rRNA transcripts were consistently detected across all treatment times, with 23S reads dominating in diagnosis and early stages of treatment shifting toward a significant predominance of 16S reads at week 24. 5S and ITS1 were inconsistently detected, whereas ITS2 was undetectable. Alpha diversity (Shannon index) increased during treatment (significant at weeks 1 and 4), while beta diversity showed significant shifts over time despite no significant differences in total M. tuberculosis abundance. Our findings suggest that it may be feasible to detect M. tuberculosis rRNA signatures in blood RNA-seq and suggest dynamic transcriptomic changes during treatment. The 16S/23S ratio and minor rRNA units may serve as complementary biomarkers for treatment monitoring and other transcriptomic-based biomarkers. Future work should validate these findings in larger cohorts using optimized RNA-seq protocols focusing on the pathogen.

Tuberculosis is major challenge to the health care system with TB associated death rates increasing annually. Optimum management of TB (particularly latent or MDR cases) warrants use of immunological approaches like subunit or peptide-based vaccination for tailoring effector immunity in patients. Since MHC class I is a potent enhancer element of host immunity and effective in clearing large variety of intracellular pathogens or tumors. In this context, we explore whether MHC-I restricted peptides from clinical isolates of M. tuberculosis can be used as an adjuvant for augmenting host immune responses. In the present study, we have synthesized various peptides from clinical isolates of M. tuberculosis which were having high affinity for Class I MHC molecules as potential immune enhancer for T cell or iNKT cell populations. We have evaluated the immunogenic potential of various MHC class I restricted epitopes (Rv2588c, Rv1357, Rv0148, Rv2973, Rv2557 and Rv2445) which were derived from clinical isolates of M. tuberculosis on increased proliferation of T or iNKT cells, release of IFN gamma secreted by T cells as well as NO as indicative parameters of immuno-stimulation. As expected, FACS and ELISA data clearly revealed that these peptides were potentially immunogenic for PBMCs from both healthy as well as 10 HC PTB patients. Our data clearly demonstrated a significant immune response in the PBMC from w PTB patients over healthy individuals which mimicked booster response. Our cytokine and nitric oxide data further revealed the influence of these peptides on sensitizing innate immune response as well. SignificanceOur study demonstrates the significance of MHC class I restricted peptides from M. tuberculosis for inducing potential immunogenic responses in host that may qualify them as potent vaccine candidate. To the best of our knowledge this is the first immune monitoring protocol describing the impact of synthetic novel MHC class I restricted T-cell epitope (Rv2588c, Rv0148) on cell mediated and innate immune response in PBMC populations and suggests their potential as vaccine candidate