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The widespread use of antibiotics has placed bacterial pathogens under intense pressure to evolve new survival mechanisms. Genomic analysis of 51,229 Mycobacterium tuberculosis ( Mtb ) clinical isolates has identified an essential transcriptional regulator, Rv1830 , herein called resR for resilience regulator, as a frequent target of positive (adaptive) selection. resR mutants do not show canonical drug resistance or drug tolerance but instead shorten the post-antibiotic effect, meaning that they enable Mtb to resume growth after drug exposure substantially faster than wild-type strains. We refer to this phenotype as antibiotic resilience. ResR acts in a regulatory cascade with other transcription factors controlling cell growth and division, which are also under positive selection in clinical isolates of Mtb . Mutations of these genes are associated with treatment failure and the acquisition of canonical drug resistance.

IntroductionPlacental transfer of maternal antibodies is essential for neonatal immunity over the first months of life. In the setting of maternal HIV infection, HIV-exposed uninfected (HEU) infants are at higher risk of developing severe infections, including active tuberculosis (TB). Given our emerging appreciation for the potential role of antibodies in the control of Mycobacterium tuberculosis (Mtb), the bacteria that causes TB, here we aimed to determine whether maternal HIV status altered the quality of Mtb-specific placental antibody transfer.MethodsAntigen-specific antibody systems serology was performed to comprehensively characterize the Mtb-specific humoral immune response in maternal and umbilical cord blood from HIV infected and uninfected pregnant people in Uganda.ResultsSignificant differences were noted in overall antibody profiles in HIV positive and negative maternal plasma, resulting in heterogeneous transfer of Mtb-specific antibodies. Altered antibody transfer in HIV infected dyads was associated with impaired binding to IgG Fc-receptors, which was directly linked to HIV viral loads and CD4 counts.ConclusionsThese results highlight the importance of maternal HIV status on antibody transfer, providing clues related to alterations in transferred maternal immunity that may render HEU infants more vulnerable to TB than their HIV-unexposed peers.

BackgroundCombatting the tuberculosis (TB) epidemic caused byMycobacterium tuberculosis(Mtb) necessitates a better understanding of the factors contributing to patient clinical outcomes and transmission. While host and environmental factors have been evaluated, the impact ofMtbgenetic background and phenotypic diversity is underexplored. Previous work has made associations betweenMtbgenetic lineages and some clinical and epidemiological features, but the bacterial traits underlying these connections are largely unknown.MethodsWe developed a high-throughput functional genomics platform for defining genotype-phenotype relationships across a panel ofMtbclinical isolates. These phenotypic fitness profiles function as intermediate traits which can be linked toMtbgenetic variants and associated with clinical and epidemiological outcomes. We applied this approach to a collection of 158Mtbstrains from a study ofMtbtransmission in Ho Chi Minh City, Vietnam.Mtbstrains were genetically tagged in multiplicate, which allowed us to pool the strains and assessin vitrocompetitive fitness using deep sequencing across a set of 14 host-relevant antibiotic and metabolic conditions. Phylogenetic and monogenic associations with these intermediate traits were identified and then associated with clinical outcomes.FindingsMtbclinical strains have a broad range of growth and drug response dynamics that can be clustered by their phylogenetic relationships. We identified novel monogenic associations withMtbfitness in various metabolic and antibiotic conditions. Among these, we find that mutations inRv1339, a phosphodiesterase, which were identified through their association with slow growth in glycerol, are further associated with treatment failure. We also identify a previously uncharacterized subclade of Lineage 1 strains (L1.1.1.1) that is phenotypically distinguished by slow growth under most antibiotic and metabolic stress conditionsin vitro. This clade is associated with cavitary disease, treatment failure, and demonstrates increased transmission potential.InterpretationHigh-throughput phenogenotyping of Mtb clinical strains enabled bacterial intermediate trait identification that can provide a mechanistic link betweenMtbgenetic variation and patient clinical outcomes.Mtbstrains associated with cavitary disease, treatment failure, and transmission potential display intermediate phenotypes distinguished by slow growth under various antibiotic and metabolic conditions. These data suggest that Mtb growth regulation is an adaptive advantage for host bacterial success in human populations, in at least some circumstances. These data further suggest markers for the underlying bacterial processes that govern these clinical outcomes.FundingNational Institutes of Allergy and Infectious Diseases: P01 AI132130 (SS, SMF); P01 AI143575 (XW, SMF); U19 AI142793 (QL, SMF); 5T32AI132120-03 (SS); 5T32AI132120-04 (SS); 5T32AI049928-17 (SS) Wellcome Trust Fellowship in Public Health and Tropical Medicine: 097124/Z/11/Z (NTTT) National Health and Medical Research Council (NHMRC)/A*STAR joint call: APP1056689 (SJD) The funding sources had no involvement in study methodology, data collection, analysis, and interpretation nor in the writing or submission of the manuscript.Research in contextEvidence before this studyWe used different combinations of the words mycobacterium tuberculosis, tuberculosis, clinical strains, intermediate phenotypes, genetic barcoding, phenogenomics, cavitary disease, treatment failure, and transmission to search the PubMed database for all studies published up until January 20th, 2022. We only considered English language publications, which biases our search. Previous work linkingMtbdeterminants to clinical or epidemiological data has made associations between bacterial lineage, or less frequently, genetic polymorphisms toin vitroorin vivomodels of pathogenesis, transmission, and clinical outcomes such as cavitary disease, treatment failure, delayed culture conversion, and severity. Many of these studies focus on the global pandemic Lineage 2 and Lineage 4Mtbstrains due in part to a deletion in a polyketide synthase implicated in host-pathogen interactions. There are a number ofMtbGWAS studies that have led to novel genetic determinants ofin vitrodrug resistance and tolerance. PreviousMtbGWAS analyses with clinical outcomes did not experimentally test any predicted phenotypes of the clinical strains. Published laboratory-based studies ofMtbclinical strains involve relatively small numbers of strains, do not identify the genetic basis of relevant phenotypes, or link findings to the corresponding clinical outcomes. There are two recent studies of other pathogens that describe phenogenomic analyses. One study of 331M. abscessusclinical strains performed one-by-one phenotyping to identify bacterial features associated with clearance of infection and another details a competition experiment utilizing three barcodedPlasmodium falciparumclinical isolates to assay antimalarial fitness and resistance.Added value of this studyWe developed a functional genomics platform to perform high-throughput phenotyping ofMtbclinical strains. We then used these phenotypes as intermediate traits to identify novel bacterial genetic features associated with clinical outcomes. We leveraged this platform with a sample of 158Mtbclinical strains from a cross sectional study ofMtbtransmission in Ho Chi Minh City, Vietnam. To enable high-throughput phenotyping of large numbers ofMtbclinical isolates, we applied a DNA barcoding approach that has not been previously utilized for the high-throughput analysis ofMtbclinical strains. This approach allowed us to perform pooled competitive fitness assays, tracking strain fitness using deep sequencing. We measured the replicative fitness of the clinical strains in multiplicate under 14 metabolic and antibiotic stress condition. To our knowledge, this is the largest phenotypic screen ofMtbclinical isolates to date. We performed bacterial GWAS to delineate theMtbgenetic variants associated with each fitness phenotype, identifying monogenic associations with several conditions. We then definedMtbphenotypic and genetic features associated with clinical outcomes. We find that a subclade ofMtbstrains, defined by variants largely involved in fatty acid metabolic pathways, share a universal slow growth phenotype that is associated with cavitary disease, treatment failure and increased transmission potential in Vietnam. We also find that mutations inRv1339, a poorly characterized phosphodiesterase, also associate with slow growthin vitroand with treatment failure in patients.Implications of all the available evidencePhenogenomic profiling demonstrates thatMtbstrains exhibit distinct growth characteristics under metabolic and antibiotic stress conditions. These fitness profiles can serve as intermediate traits for GWAS and association with clinical outcomes. Intermediate phenotyping allows us to examine potential processes by which bacterial strain differences contribute to clinical outcomes. Our study identifies clinical strains with slow growth phenotypes underin vitromodels of antibiotic and host-like metabolic conditions that are associated with adverse clinical outcomes. It is possible that the bacterial intermediate phenotypes we identified are directly related to the mechanisms of these outcomes, or they may serve as markers for the causal yet unidentified bacterial determinants. Via the intermediate phenotyping, we also discovered a surprising diversity inMtbresponses to the new anti-mycobacterial drugs that target central metabolic processes, which will be important in considering roll-out of these new agents. Our study and others that have identifiedMtbdeterminants of TB clinical and epidemiological phenotypes should inform efforts to improve diagnostics and drug regimen design.

Induction of lipid-laden foamy macrophages is a cellular hallmark of tuberculosis (TB) disease, which involves the transformation of infected phagolysosomes from a site of killing into a nutrient-rich replicative niche. Here, we show that a terpenyl nucleoside shed from Mycobacterium tuberculosis, 1-tuberculosinyladenosine (1-TbAd), caused lysosomal maturation arrest and autophagy blockade, leading to lipid storage in M1 macrophages. Pure 1-TbAd, or infection with terpenyl nucleoside-producing M. tuberculosis, caused intralysosomal and peribacillary lipid storage patterns that matched both the molecules and subcellular locations known in foamy macrophages. Lipidomics showed that 1-TbAd induced storage of triacylglycerides and cholesterylesters and that 1-TbAd increased M. tuberculosis growth under conditions of restricted lipid access in macrophages. Furthermore, lipidomics identified 1-TbAd-induced lipid substrates that define Gaucher's disease, Wolman's disease, and other inborn lysosomal storage diseases. These data identify genetic and molecular causes of M. tuberculosis-induced lysosomal failure, leading to successful testing of an agonist of TRPML1 calcium channels that reverses lipid storage in cells. These data establish the host-directed cellular functions of an orphan effector molecule that promotes survival in macrophages, providing both an upstream cause and detailed picture of lysosome failure in foamy macrophages.

The mechanisms and regulation of RNA degradation in mycobacteria have been subject to increased interest following the identification of interplay between RNA metabolism and drug resistance. Mycobacteria encode multiple ribonucleases that are predicted to participate in mRNA degradation and/or processing of stable RNAs. RNase E is an endoribonuclease hypothesized to play a major role in mRNA degradation due to its essentiality in mycobacteria and its role in mRNA degradation in gram- negative bacteria. Here, we defined the impact of RNase E on mRNA degradation rates transcriptome- wide in the non-pathogenic modelMycolicibacterium smegmatis. RNase E played a rate-limiting role in the degradation of at least 89% of protein-coding genes, with leadered transcripts generally being more affected by RNase E repression than leaderless transcripts. There was an apparent global slowing of transcription in response to knockdown of RNase E, suggesting thatM. smegmatisregulates transcription in responses to changes in mRNA degradation. This compensation was incomplete, as the abundance of most transcripts increased upon RNase E knockdown. We assessed the sequence preferences for cleavage by RNase E transcriptome-wide in bothM. smegmatisandM. tuberculosis, and found a consistent bias for cleavage in C-rich regions. Purified RNase E had a clear preference for cleavage immediately upstream of cytidines, distinct from the sequence preferences of RNase E in gram-negatives. We furthermore report a high-resolution map of mRNA cleavage sites inM. tuberculosis, which occur primarily within the RNase E-preferred sequence context, confirming RNase E as a broad contributor toM. tuberculosistranscriptome structure.

Development of an effective tuberculosis (TB) vaccine has suffered from an incomplete understanding of the correlates of protection against Mycobacterium tuberculosis (Mtb). Intravenous (i.v.) vaccination with Bacille Calmette–Guerin (BCG) provides nearly complete protection against TB in rhesus macaques, but the antibody response it elicits remains incompletely defined. Here we show that i.v. BCG drives superior antibody responses in the plasma and the lungs of rhesus macaques compared to traditional intradermal BCG administration. While i.v. BCG broadly expands antibody titers and functions, IgM titers in the plasma and lungs of immunized macaques are among the strongest markers of reduced bacterial burden. IgM was also enriched in macaques that received protective vaccination with an attenuated strain of Mtb. Finally, an Mtb-specific IgM monoclonal antibody reduced Mtb survival in vitro. Collectively, these data highlight the potential importance of IgM responses as a marker and mediator of protection against TB. Alter and colleagues show that IgM titers in the plasma and bronchoalveolar lavage fluid represent markers of reduced Mtb burden in rhesus macaques vaccinated intravenously with Bacille Calmette–Guerin.

The growth of mycobacterial cells requires successful coordination between elongation and septation. However, it is not clear which factors mediate this coordination. Here, we studied the function and post-translational modification of an essential division factor, SepIVA, in Mycobacterium smegmatis. We find that SepIVA is arginine methylated, and that alteration of its methylation sites affects both septation and polar elongation of Msmeg. Furthermore, we show that SepIVA regulates the localization of MurG and that this regulation may impact polar elongation. Finally, we map SepIVA's two regulatory functions to different ends of the protein: the N-terminus regulates elongation while the C-terminus regulates division. These results establish SepIVA as a regulator of both elongation and division and characterize a physiological role for protein arginine methylation sites for the first time in mycobacteria.

Background Cynomolgus macaque (Macaca fascicularis) is an attractive animal model for the study of human disease and is extensively used in biomedical research. Cynomolgus macaques share behavioral, physiological, and genomic traits with humans and recapitulate human disease manifestations not observed in other animal species. To improve the use of the cynomolgus macaque model to investigate immune responses, we defined and characterized the T cell receptor (TCR) repertoire. Result We identified and analyzed the alpha (TRA), beta (TRB), gamma (TRG), and delta (TRD) TCR loci of the cynomolgus macaque. The expressed repertoire was determined using 22 unique lung samples from Mycobacterium tuberculosis infected cynomolgus macaques by single cell RNA sequencing. Expressed TCR alpha (TRAV) and beta (TRBV) variable region genes were enriched and identified using gene specific primers, which allowed their functional status to be determined. Analysis of the primers used for cynomolgus macaque TCR variable region gene enrichment showed they could also be used to amplify rhesus macaque (M. mulatta) variable region genes. Conclusion The genomic organization of the cynomolgus macaque has great similarity with the rhesus macaque and they shared > 90% sequence similarity with the human TCR repertoire. The identification of the TCR repertoire facilitates analysis of T cell immunity in cynomolgus macaques.

Made available in DSpace on 2022-04-28T19:40:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-07-01 Background: The COVID-19 pandemic is having profound mental health consequences for many people. Concerns have been expressed that, at their most extreme, these consequences could manifest as increased suicide rates. We aimed to assess the early effect of the COVID-19 pandemic on suicide rates around the world. Methods: We sourced real-time suicide data from countries or areas within countries through a systematic internet search and recourse to our networks and the published literature. Between Sept 1 and Nov 1, 2020, we searched the official websites of these countries’ ministries of health, police agencies, and government-run statistics agencies or equivalents, using the translated search terms “suicide” and “cause of death”, before broadening the search in an attempt to identify data through other public sources. Data were included from a given country or area if they came from an official government source and were available at a monthly level from at least Jan 1, 2019, to July 31, 2020. Our internet searches were restricted to countries with more than 3 million residents for pragmatic reasons, but we relaxed this rule for countries identified through the literature and our networks. Areas within countries could also be included with populations of less than 3 million. We used an interrupted time-series analysis to model the trend in monthly suicides before COVID-19 (from at least Jan 1, 2019, to March 31, 2020) in each country or area within a country, comparing the expected number of suicides derived from the model with the observed number of suicides in the early months of the pandemic (from April 1 to July 31, 2020, in the primary analysis). Findings: We sourced data from 21 countries (16 high-income and five upper-middle-income countries), including whole-country data in ten countries and data for various areas in 11 countries). Rate ratios (RRs) and 95% CIs based on the observed versus expected numbers of suicides showed no evidence of a significant increase in risk of suicide since the pandemic began in any country or area. There was statistical evidence of a decrease in suicide compared with the expected number in 12 countries or areas: New South Wales, Australia (RR 0·81 [95% CI 0·72–0·91]); Alberta, Canada (0·80 [0·68–0·93]); British Columbia, Canada (0·76 [0·66–0·87]); Chile (0·85 [0·78–0·94]); Leipzig, Germany (0·49 [0·32–0·74]); Japan (0·94 [0·91–0·96]); New Zealand (0·79 [0·68–0·91]); South Korea (0·94 [0·92–0·97]); California, USA (0·90 [0·85–0·95]); Illinois (Cook County), USA (0·79 [0·67–0·93]); Texas (four counties), USA (0·82 [0·68–0·98]); and Ecuador (0·74 [0·67–0·82]). Interpretation: This is the first study to examine suicides occurring in the context of the COVID-19 pandemic in multiple countries. In high-income and upper-middle-income countries, suicide numbers have remained largely unchanged or declined in the early months of the pandemic compared with the expected levels based on the pre-pandemic period. We need to remain vigilant and be poised to respond if the situation changes as the longer-term mental health and economic effects of the pandemic unfold. Funding: None. Centre for Mental Health Melbourne School of Population and Global Health University of Melbourne Swansea University Medical School Translational Health Research Institute Western Sydney University Ministry of Public Health Department of Health Promotion National Confidential Inquiry into Suicide and Safety in Mental Health University of Manchester Centre for Mental Health and Safety and National Institute for Health Research Patient Safety Translational Research Centre University of Manchester School of Public Health National Suicide Research Foundation University College Cork Australian Institute for Suicide Research and Prevention School of Applied Psychology Griffith University Institute for Life Course Health Research Department of Global Health Stellenbosch University Working Group on Prevention of Suicide and Depression at Public Health Council Department of Psychiatry Blekinge Hospital Botucatu Medical School Universidade Estadual Paulista Instituto Nacional de Psiquiatría Ramon de la Fuente Muñiz University of Rochester Medical Center Region Friuli Venezia Giulia Central Health Directorate Outpatient and Inpatient Care Service Department of Medicine University of Udine Institute of Health Behaviors and Community Sciences College of Public Health National Taiwan University Thames Valley Local Criminal Justice Board Department of Psychiatry Psychotherapy and Psychosomatics Medical University of Innsbruck Center for Outcomes Research and Evaluation Yale School of Medicine Coroners Court of Victoria Danish Research Institute for Suicide Prevention Department of Mental Health Johns Hopkins School of Public Health Centre for Mental Health Research Australian National University Brigham and Women's Hospital Department of Emergency Medicine School of Population Health University of Auckland Magistrates Court of Tasmania (Coronial Division) Bureau of Vital Records and Statistics Louisiana Office of Public Health Ministry of Public Health Undersecretary of Health Services Research Department, 113 Suicide Prevention Departments of Psychiatry and Epidemiology Columbia University Medical Center/New York State Psychiatric Institute Centre for Suicide Research University of Oxford Louisiana Department of Health Greater Manchester Mental Health NHS Foundation Trust Department of Psychiatry Aga Khan University KU Leuven Center for Contextual Psychiatry Population Health Sciences Bristol Medical School University of Bristol South Asian Clinical Toxicology Research Collaboration Faculty of Medicine University of Peradeniya World Health Organization Country Office for Nepal Karolinska Institutet Bekhterev National Medical Research Center of Psychiatry and Neurology Pavlov First Saint Petersburg State Medical University Unit Suicide Research and Mental Health Promotion Department of Social and Preventive Medicine Center for Public Health Medical University of Vienna Department of Child and Adolescent Psychiatry Medical University of Vienna School of Psychology University of Nottingham Self-Harm Research Group School of Psychology University of Nottingham Mental Health Centre Copenhagen Department of Psychiatry and Psychotherapy Klinikum Klagenfurt am Wörthersee Suicidal Behaviour Research Lab University of Glasgow Preventing Deaths from Poisoning Research Group University of Edinburgh Usher Institute University of Edinburgh Suicide Research and Prevention Center Shanghai Mental Health Center Shanghai Jiao Tong University School of Medicine Departments of Psychiatry and Epidemiology Columbia University Department of Child and Adolescent Psychiatry and Psychotherapy University of Ulm Psychosocial Services in Vienna National Centre for Suicide Research and Prevention Institute of Clinical Medicine University of Oslo Department of Child and Adolescent Psychiatry Psychotherapy and Psychosomatics University Hospital Leipzig Department of Psychiatry and Psychotherapeutic Medicine Landeskrankenhaus Villach Department of Psychiatry Psychosomatic Medicine and Psychotherapy University Hospital Frankfurt Department of Borderline Disorders and Psychotherapy Bekhterev National Medical Research Center of Psychiatry and Neurology Saint Petersburg State University Department of Psychiatry Health Authority Frankfurt am Main Department of Addictive Disorders Psychiatry and Psychotherapy LVR-Klinik Köln Department of Psychiatry Psychosomatic Medicine and Psychotherapy Goethe-University Organizational-Scientific Department Bekhterev National Medical Research Center of Psychiatry and Neurology Department of Psychiatry University of Toronto Department of Psychiatry Sunnybrook Health Sciences Centre Waseda University Faculty of Political Science and Economics Sneha—Suicide Prevention Centre Voluntary Health Services Department of Community Medicine Faculty of Medicine and Allied Sciences Rajarata University of Sri Lanka Department of Psychiatry Sackler School of Medicine Tel Aviv University and Geha Mental Health Center Division of Molecular Imaging and Neuropathology New York State Psychiatric Institute and Department of Psychiatry Columbia University National Institute of Health Research Biomedical Research Centre University Hospitals Bristol and Weston NHS Foundation Trust University of Bristol Department for Psychiatry University Psychiatric Hospital Vrapče School of Medicine University of Zagreb Botucatu Medical School Universidade Estadual Paulista

Toxin-antitoxin (TA) systems allow bacteria to adapt to changing environments without altering gene expression. Despite being overrepresented in Mycobacterium tuberculosis, their physiological roles remain elusive. We describe a TA system in M. tuberculosis which we named TacAT due to its homology to previously discovered systems in Salmonella. The toxin, TacT, blocks growth by acetylating glycyl-tRNAs and inhibiting translation. Its effects are reversed by the enzyme peptidyl tRNA hydrolase (Pth), which also cleaves peptidyl tRNAs that are prematurely released from stalled ribosomes. Pth is essential in most bacteria and thereby has been proposed as a promising drug target for complex pathogens like M. tuberculosis. Transposon sequencing data suggest that the

Controlled human infection models can be helpful to study pathogenesis and immune responses as a basis for the development of vaccines. In controlled human infection models, human challenge agents are used to infect healthy volunteers, therefore, ethical considerations include that the exposure studies need to be safe and results should be meaningful, e.g. contribute to a better cure. Both in the US and in Europe, the level of Good Manufacturing Practice required is related to the phase of the study ('sliding scale Good Manufacturing Practice'), and, hence, is much more open to speedy drug development than anticipated. Recommendations included: the development of guidelines for human challenge agents; a focus on strain selection, in particular with regard to strain infectivity, stability and purity; the use of whole genome sequencing; a reference repository of challenge agents, the need for early exchange with regulators to ensure acceptability of strain selection and manufacturing for later drug development; sharing of models and challenge agents.

Novel vaccination and therapeutic strategies are urgently needed to mitigate the tuberculosis (TB) epidemic. While extensive efforts have focused on potentiating cell-mediated immunity to controlMycobacterium tuberculosis(Mtb) infection, less effort has been invested in exploiting the humoral immune system to combatMtb. Emerging data point to a role for antibodies in microbial control ofMtb, however the precise mechanism(s) of this control remain incompletely understood. Here we took an antibody Fc-engineering approach to determine whether Fc-modifications could improve the ability of antibodies to restrictMtb, and to define Fc-mediated mechanism(s) antibodies leverage for this restriction. Using an antibody specific to the capsular polysaccharide α-glucan, we engineer a panel of Fc variants to augment or dampen select antibody effector functions, rationally building antibodies with enhanced capacity to promoteMtbrestriction in a human whole blood model of infection. Surprisingly, restrictive Fc-engineered antibodies driveMtbcontrol in a neutrophil, not monocyte, dependent manner. Using single cell RNA sequencing, we show that restrictive antibodies promote neutrophil survival and expression of cell intrinsic antimicrobial programs. These data provide a roadmap for exploiting Fc-engineered antibodies as a novel class of TB therapeutics able to harness the protective functions of neutrophils to achieve disease control.

Individuals co-infected with HIV and Mycobacterium tuberculosis (Mtb) are more likely to develop severe tuberculosis (TB) disease than HIV-naive individuals. To understand how a chronic pre-existing Simian immunodeficiency virus (SIV) infection impairs the early immune response to Mtb, we used the Mauritian cynomolgus macaque (MCM) model of SIV/Mtb co-infection. We examined the relationship between peripheral viral control and Mtb burden, Mtb dissemination, and T cell function between SIV+ spontaneous controllers, SIV+ non-controllers, and SIV-naive MCM who were challenged with a barcoded Mtb Erdman strain 6 months post-SIV infection and necropsied 6 weeks post-Mtb infection. Mycobacterial burden was highest in the SIV+ non-controllers in all assessed tissues. In lung granulomas, the frequency of TNF-α-producing CD4

There is growing evidence that genetic diversity in Mycobacterium tuberculosis, the causative agent of tuberculosis, contributes to the outcomes of infection and public health interventions, such as vaccination. Epidemiological studies suggest that among the phylogeographic lineages of M. tuberculosis, strains belonging to a sublineage of Lineage 2 (mL2) are associated with concerning clinical features, including hypervirulence, treatment failure, and vaccine escape. The global expansion and increasing prevalence of this sublineage has been attributed to the selective advantage conferred by these characteristics, yet confounding host and environmental factors make it difficult to identify the bacterial determinants driving these associations in human studies. Here, we developed a molecular barcoding strategy to facilitate high-throughput, experimental phenotyping of M. tuberculosis clinical isolates. This approach allowed us to characterize growth dynamics for a panel of genetically diverse M. tuberculosis strains during infection and after vaccination in the mouse model. We found that mL2 strains exhibit distinct growth dynamics

Macrophages are a protective replicative niche for Mycobacterium tuberculosis (Mtb) but can kill the infecting bacterium when appropriately activated. To identify mechanisms of clearance, we compared levels of bacterial restriction by human macrophages after treatment with 26 compounds, including some currently in clinical trials for tuberculosis. All-trans-retinoic acid (ATRA), an active metabolite of vitamin A, drove the greatest increase in Mtb control. Bacterial clearance was transcriptionally and functionally associated with changes in macrophage cholesterol trafficking and lipid metabolism. To determine how these macrophage changes affected bacterial control, we performed the first Mtb CRISPR interference screen in an infection model, identifying Mtb genes specifically required to survive in ATRA-activated macrophages. These data showed that ATRA treatment starves Mtb of cholesterol and the downstream metabolite propionyl coenzyme A (propionyl-CoA). Supplementation with sources of propionyl-CoA, including cholesterol, abrogated the restrictive effect of ATRA. This work demonstrates that targeting the coupled metabolism of Mtb and the macrophage improves control of infection and that it is possible to genetically map the mode of bacterial death using CRISPR interference.

The outcome of infectious diseases may depend on the interaction between human and pathogen genomic variations. We explore this relationship in tuberculosis (TB) by conducting a genome-to-genome (g2g) study of paired genomes from humans and the infectious agent Mycobacterium tuberculosis (Mtb) in 1,556 Peruvian TB patients. We identified a significant association between a human variant in the FLOT1 gene and a unique Mtb Lineage 2 (L2) subclade. The host allele affects FLOT1 expression in multiple tissue and cell types including lung, the primary site of TB disease. Phylogenetic analysis shows that the Mtb subclade has expanded rapidly in Peru since its emergence in the 1950s. Unbiased phenotypic profiling demonstrates that strains from the interacting Mtb subclade display different redox metabolism from other L2 strains. This study presents clear evidence that human and bacterial genetic variation interact together to produce different clinical outcomes.

Shigellosis causes most diarrheal deaths worldwide, particularly affecting children. Shigella invades and replicates in the epithelium of the large intestine, eliciting inflammation and tissue destruction. To understand how Shigella rewires macrophages prior to epithelium invasion, we performed genome-wide and focused secondary CRISPR knockout and CRISPR interference (CRISPRi) screens in Shigella flexneri-infected human monocytic THP-1 cells. Knockdown of the Toll-like receptor 1/2 signaling pathway significantly reduced proinflammatory cytokine and chemokine production, enhanced host cell survival, and controlled intracellular pathogen growth. Knockdown of the enzymatic component of the mitochondrial pyruvate dehydrogenase complex enhanced THP-1 cell survival. Small-molecule inhibitors blocking key components of these pathways had similar effects; these were validated with human monocyte-derived macrophages, which closely mimic the in vivo physiological state of macrophages postinfection. High-throughput CRISPR screens can elucidate how S. flexneri triggers inflammation and redirects host pyruvate catabolism for energy acquisition before killing macrophages, pointing to new shigellosis therapies.

Toxin-antitoxin (TA) systems allow bacteria to adapt to changing environments without altering gene expression. Despite being overrepresented inMycobacterium tuberculosis(Mtb), their individual physiological roles remain elusive. We describe a TA system inMtbwhich we have named TacAT due to its homology to previously discovered systems in Salmonella. The toxin, TacT, blocks growth by acetylating glycyl-tRNAs and inhibiting translation. Its effects are reversed by the enzyme peptidyl tRNA hydrolase (Pth), which also cleaves peptidyl tRNAs that are prematurely released from stalled ribosomes. Pth is essential in most bacteria and thereby has been proposed as a promising drug target for complex pathogens likeMtb. Transposon sequencing data suggest that thetacAToperon is nonessential forMtbgrowthin vitro, and premature stop mutations in this TA system present in some clinical isolates suggest that it is also dispensablein vivo. We assessed whether TacT modulatespthessentiality inMtb, as drugs targeting Pth might be ineffective if TacAT is disrupted. We find thatpthessentiality is unaffected by the absence oftacAT. These results highlight a fundamental aspect of mycobacterial biology and indicate that Pth’s essential role hinges on its peptidyl-tRNA hydrolase activity. Our work underscores Pth’s potential as a viable target for new antibiotics.

BACKGROUND: Idiopathic aplastic anemia is a potentially lethal disease, characterized by T-cell mediated autoimmune attack of bone marrow hematopoietic stem cells. Standard of care therapies (stem cell transplantation or immunosuppression) are effective but associated with a risk of serious toxicities. METHODS: An 18-year-old man presented with aplastic anemia in the context of a germline gain-of-function variant in STAT1. Treatment with the JAK1 inhibitor itacitinib resulted in a rapid resolution of aplastic anemia and a sustained recovery of hematopoiesis. Peripheral blood and bone marrow samples were compared before and after JAK1 inhibitor therapy. FINDINGS: Following therapy, samples showed a decrease in the plasma concentration of interferon-γ, a decrease in PD1-positive exhausted CD8+ T cells population, and a decrease in an interferon responsive myeloid population. Single cell analysis of chromatin accessibility showed decreased accessibility of STAT1 across CD4+ and CD8+ T cells, as well as CD14+ monocytes. To query whether other cases of aplastic anemia share a similar STAT1-mediated pathophysiology, we examined a cohort of patients with idiopathic aplastic anemia. Bone marrow from six of nine patients also displayed abnormal STAT1 hyper-activation. CONCLUSIONS: These findings raise the possibility that STAT1-hyperactivition defines a subset of idiopathic aplastic anemia patients for whom JAK inhibition may be an efficacious therapy.

Growth of mycobacterial cells requires successful coordination between elongation and septation of the cell wall. However, it is not clear which factors directly mediate this coordination. Here, we studied the function and post-translational modification of an essential division factor, SepIVA, inMycobacterium smegmatis. We find that SepIVA is arginine methylated, and that alteration of these methylation sites affects both septation and polar elongation ofMsmeg. Furthermore, we show that SepIVA regulates the localization of MurG, and that this regulation may impact polar elongation. Finally, we map SepIVA’s two regulatory functions to different sites on the protein: the N-terminus regulates elongation while the C-terminus regulates division. These results establish SepIVA as a regulator of both elongation and division and characterize a physiological role for protein arginine methylation sites for the first time in mycobacteria.

South Africa has the highest prevalence of HIV and tuberculosis (TB) co-infection globally. Recurrent TB, caused by relapse or reinfection, makes up the majority of TB cases in South Africa, and HIV infected individuals have a greater likelihood of developing recurrent TB. Given that TB remains a leading cause of death for HIV infected individuals, and correlates of TB recurrence protection/risk have yet to be defined, here we sought to understand the antibody associated mechanisms of recurrent TB by investigating the humoral response in a longitudinal cohort of HIV co-infected individuals previously treated for TB with and without recurrent disease during follow-up, in order to identify antibody correlates of protection between individuals who do not have recurrent TB and individuals who do. We used a high-throughput, “systems serology” approach to profile biophysical and functional characteristics of antibodies targeting antigens from Mycobacterium tuberculosis (Mtb). Differences in antibody profiles were noted between individuals with and without recurrent TB, albeit these differences were largely observed close to the time of re-diagnosis. Individuals with recurrent TB had decreased Mtb-antigen specific IgG3 titers, but not other IgG subclasses or IgA, compared to control individuals. These data point to a potential role for Mtb-specific IgG3 responses as biomarkers or direct mediators of protective immunity against Mtb recurrence.

Toxin-antitoxin systems are widely distributed genetic modules typically featuring toxins that can inhibit bacterial growth and antitoxins that can reverse inhibition. Although Escherichia coli encodes 11 toxins with known or putative endoribonuclease activity, the targets of most of these toxins remain poorly characterized. Using a new RNA sequencing (RNA-seq) pipeline that enables the mapping and quantification of RNA cleavage with single-nucleotide resolution, we characterized the targets and specificities of 9 endoribonuclease toxins from E. coli. We found that these toxins use low-information cleavage motifs to cut a significant proportion of mRNAs in E. coli, but not tRNAs or the rRNAs from mature ribosomes. However, all the toxins, including those that are ribosome dependent and cleave only translated RNA, inhibit ribosome biogenesis. This inhibition likely results from the cleavage of ribosomal protein transcripts, which disrupts the stoichiometry and biogenesis of new ribosomes and causes the accumulation of aberrant ribosome precursors. Collectively, our results provide a comprehensive, global analysis of endoribonuclease-based toxin-antitoxin systems in E. coli and support the conclusion that, despite their diversity, each disrupts translation and ribosome biogenesis. IMPORTANCE Toxin-antitoxin (TA) systems are widespread genetic modules found in almost all bacteria that can regulate their growth and may play prominent roles in phage defense. Escherichia coli encodes 11 TA systems in which the toxin is a known or predicted endoribonuclease. The targets and cleavage specificities of these endoribonucleases have remained largely uncharacterized, precluding an understanding of how each impacts cell growth and an assessment of whether they have distinct or overlapping targets. Using a new and broadly applicable RNA-seq pipeline, we carried out a global analysis of 9 endoribonuclease toxins from E. coli. We found that each uses a relatively low-information cleavage motif to cut a large proportion of mRNAs in E. coli, but not tRNAs or mature rRNAs. Notably, although the precise set of targets varies, each toxin efficiently disrupts ribosome biogenesis, primarily by cleaving the mRNAs of ribosomal proteins. In sum, the analyses presented provide new, comprehensive insights into the cleavage specificities and targets of almost all endoribonuclease toxins in E. coli. Despite different specificities, our work reveals a striking commonality in function, as each toxin disrupts ribosome biogenesis and translation.

The pathogenicity of Mycobacterium tuberculosis depends upon its ability to catabolize host cholesterol. Upregulation of the methylcitrate cycle (MCC) is required to assimilate and detoxify propionyl-CoA, a cholesterol degradation product. The transcription of key genes prpC and prpD in MCC is activated by MtPrpR, a member of a family of prokaryotic transcription factors whose structures and modes of action have not been clearly defined. We show that MtPrpR has a novel overall structure and directly binds to CoA or short-chain acyl-CoA derivatives to form a homotetramer that covers the binding cavity and locks CoA tightly inside the protein. The regulation of this process involves a [4Fe4S] cluster located close to the CoA-binding cavity on a neighboring chain. Mutations in the [4Fe4S] cluster binding residues rendered MtPrpR incapable of regulating MCC gene transcription. The structure of MtPrpR without the [4Fe4S] cluster-binding region shows a conformational change that prohibits CoA binding. The stability of this cluster means it is unlikely a redox sensor but may function by sensing ambient iron levels. These results provide mechanistic insights into this family of critical transcription factors who share similar structures and regulate gene transcription using a combination of acyl-CoAs and [4Fe4S] cluster.

Exposure to Mycobacterium tuberculosis (Mtb) results in heterogeneous clinical outcomes including primary progressive tuberculosis and latent Mtb infection (LTBI). Mtb infection is identified using the tuberculin skin test and interferon-γ (IFN-γ) release assay IGRA, and a positive result may prompt chemoprophylaxis to prevent progression to tuberculosis. In the present study, we report on a cohort of Ugandan individuals who were household contacts of patients with TB. These individuals were highly exposed to Mtb but tested negative by IFN-γ release assay and tuberculin skin test, ‘resisting’ development of classic LTBI. We show that ‘resisters’ possess IgM, class-switched IgG antibody responses and non-IFN-γ T cell responses to the Mtb-specific proteins ESAT6 and CFP10, immunologic evidence of exposure to Mtb. Compared to subjects with classic LTBI, ‘resisters’ display enhanced antibody avidity and distinct Mtb-specific IgG Fc profiles. These data reveal a distinctive adaptive immune profile among Mtb-exposed subjects, supporting an expanded definition of the host response to Mtb exposure, with implications for public health and the design of clinical trials. New immune biomarkers of exposure to tuberculosis may require a rethink of evidence of Mycobacterium tuberculosis infection and control.

Toxin-antitoxin systems are widely distributed genetic modules typically featuring toxins that can inhibit bacterial growth and antitoxins that can reverse inhibition. Although Escherichia coli encodes 11 toxins with known or putative endoribonuclease activity, the target of most of these toxins remain poorly characterized. Using a new RNA-seq pipeline that enables the mapping and quantification of RNA cleavage with single-nucleotide resolution, we characterize the targets and specificities of 9 endoribonuclease toxins from E. coli. We find that these toxins use low-information cleavage motifs to cut a significant proportion of mRNAs in E. coli, but not tRNAs or the rRNAs from mature ribosomes. However, all the toxins, including those that are ribosome-dependent and cleave only translated RNA, inhibit ribosome biogenesis. This inhibition likely results from the cleavage of ribosomal protein transcripts, which disrupts the stoichiometry and biogenesis of new ribosomes and causes the accumulation of aberrant ribosome precursors. Collectively, our results provide a comprehensive, global analysis of endoribonuclease-based toxin-antitoxin systems in E. coli and support the conclusion that, despite their diversity, each disrupts translation and ribosome biogenesis.ImportanceToxin-antitoxin systems are widespread genetic modules found in almost all bacteria that can regulate their growth and may play prominent roles in phage defense. Escherichia coli encodes 11 TA systems in which the toxin is a known or predicted endoribonuclease. The targets and cleavage specificities of these endoribonucleases have remained largely uncharacerized, precluding an understanding of how each impacts cell growth and an assessment of whether they have distinct or overlapping targets. Using a new and broadly applicable RNA-seq pipeline, we present a global analysis of 9 endoribonulease toxins from E. coli. We find that each uses a relatively low-information cleavage motif to cut a large proportion of mRNAs in E. coli, but not tRNAs or mature rRNAs. Notably, although the precise set of targets varies, each toxin efficiently disrupts ribosome biogenesis, primarily by cleaving the mRNAs of ribosomal proteins. In sum, the analyses presented provide new, comprehensive insights into the cleavage specificities and targets of almost all endoribonuclease toxins in E. coli. Despite different specificities, our work reveals a striking commonality in function as each toxin disrupts ribosome biogenesis and translation.

With an estimated 25% of the global population infected withMycobacterium tuberculosis(Mtb), tuberculosis (TB) remains a leading cause of death by infectious diseases. Humoral immunity following TB treatment is largely uncharacterized, and antibody profiling could provide insights into disease resolution. Here we focused on the distinctive TB-specific serum antibody features in active TB disease (ATB) and compared them with latent TB infection (LTBI) or treated ATB (txATB). As expected, di-galactosylated glycan structures (lacking sialic acid) found on IgG-Fc differentiated LTBI from ATB, but also discriminated txATB from ATB. Moreover, TB-specific IgG4 emerged as a novel antibody feature that correlated with active disease, elevated in ATB, but significantly diminished after therapy. These findings highlight 2 novel TB-specific antibody changes that track with the resolution of TB and may provide key insights to guide TB therapy.

Individuals infected with both HIV and Mycobacterium tuberculosis (Mtb) are more likely to develop severe Tuberculosis (TB) disease than HIV-naïve individuals. To understand how a chronic pre-existing Simian immunodeficiency virus (SIV) infection impairs the early immune response to Mtb, we used the Mauritian cynomolgus macaque (MCM) model of SIV/Mtb co-infection. We examined the relationship between peripheral viral control and Mtb burden, Mtb dissemination, and immunological function between SIV+ spontaneous controllers, SIV+ non-controllers, and SIV-naïve MCM who were challenged with a barcoded Mtb Erdman strain and necropsied six weeks post infection. Mycobacterial burden was highest in the SIV+ non-controllers in all assessed tissues. In lung granulomas, we found the frequency of CD4+ T cells producing TNFα was reduced in all SIV+ MCM, but CD4+ T cells producing IFNγ were only lower in the SIV+ non-controllers. Further, while all SIV+ MCM had more PD1+ and TIGIT+ T cells in the lung granulomas relative to SIV-naïve MCM, SIV+ controllers exhibited the highest frequency of cells expressing these markers. To measure the effect of SIV infection on within-host bacterial dissemination, we sequenced the molecular barcodes of Mtb present in each tissue and characterized the complexity of the Mtb populations. While Mtb population complexity was not associated with infection group, lymph nodes had increased complexity when compared to lung granulomas across all groups. These results provide evidence SIV+ animals, independent of viral control, exhibit dysregulated immune responses and enhanced dissemination of Mtb, likely contributing to the poor TB disease course across all SIV/Mtb co-infected animals.ImportanceHIV and TB remain significant global health issues, despite the availability of treatments. Individuals with HIV, including those who are virally suppressed, are at an increased risk to develop and succumb to severe TB disease when compared to HIV-naïve individuals. Our study aims to understand the relationship between SIV replication, mycobacterial growth, and immunological function in the tissues of co-infected Mauritian cynomolgus macaques during the early phase of Mtb infection. Here we demonstrate that increased viral replication is associated with increased bacterial burden in the tissues and impaired immunologic responses, and that the damage attributed to virus infection is not fully eliminated when animals spontaneously control virus replication.

Development of an effective tuberculosis (TB) vaccine has suffered from an incomplete understanding of the correlates of protection against Mycobacterium tuberculosis (Mtb). However, recent work has shown that compared to standard intradermal Bacille Calmette-Guerin (BCG) vaccination, intravenous (IV) BCG vaccination provides nearly complete protection against TB in rhesus macaques. While studies have focused on cellular immunity in this setting, the antibody response elicited by IV BCG vaccination remains incompletely defined. Using an agnostic antibody profiling approach, here we show that IV BCG drives superior antibody responses in the plasma and the bronchoalveolar lavage fluid (BAL). While IV BCG immunization resulted in the expansion of a robust IgM, IgG, IgA, Fc-receptor binding antibodies, and antibody effector functions in the BAL, IgM titers were among the strongest markers of reduced bacterial burden in the plasma and BAL of BCG immunized animals. Moreover, IgM immunity was also enriched among animals receiving protective vaccination with an attenuated Mtb strain. Finally, a LAM-specific IgM monoclonal antibody reduced Mtb survival in vitro. Collectively, these data highlight the potential importance of IgM responses as a marker and as a functional mediator of protection against TB.