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Rengarajan, J.

Publications and source records attributed to Rengarajan, J..

3 recordsLinked to original sources

Title: Multimodal profiling reveals Mycobacterium tuberculosis restricts lung mitochondrial immunometabolism to promote pathogenesis

Early events in the lung that shape protective immune responses to M. tuberculosis (Mtb) infection are not well understood but are critical for developing better vaccines and immunomodulatory therapies for tuberculosis. Here, we used high-dimensional flow cytometry, single-cell transcriptomics, and untargeted metabolomics to define the early lung immune environment that precedes the development of protective versus pathogenic outcomes following aerosolized Mtb infection of mice. We show that Mtb induced sustained glycolysis in the lung while restricting oxidative phosphorylation (OXPHOS) and impairing mitochondria, in part through the Mtb serine protease Hip1, leading to low energy output and suboptimal macrophage-T cell interactions that promoted pathogenic immunity. However, robust induction of mitochondrial OXPHOS, amino acid metabolism, and fatty acid oxidation in the early lung resulted in high ATP output and enhanced innate-T cell signaling networks that stimulated protective immune responses. Moreover, we identified a novel mitochondrial immunometabolic lung signature associated with protective outcomes to Mtb infection in animal models and humans. Our studies identify induction of mitochondrial dysfunction as a mechanism employed by Mtb to manipulate lung immunometabolism to its benefit and reveal that maintenance of intact mitochondrial metabolism in the early lung is pivotal for generating protective outcomes to Mtb infection.

immunology↗

Rare Variable M. tuberculosis Antigens induce predominant Th17 responses in human infection

CD4 T cells are essential for immunity to M. tuberculosis (Mtb), and emerging evidence indicates that IL-17-producing Th17 cells contribute to immunity to Mtb. While identifying protective T cell effector functions is important for TB vaccine design, T cell antigen specificity is also likely to be important. To identify antigens that induce protective immunity, we reasoned that as in other pathogens, effective immune recognition drives sequence diversity in individual Mtb antigens. We previously identified Mtb genes under evolutionary diversifying selection pressure whose products we term Rare Variable Mtb Antigens (RVMA). Here, in two distinct human cohorts with recent exposure to TB, we found that RVMA preferentially induce CD4 T cells that express RoR{gamma}t and produce IL-17, in contrast to classical Mtb antigens that induce T cells that produce IFN{gamma}. Our results suggest that RVMA can be valuable antigens in vaccines for those already infected with Mtb to amplify existing antigen-specific Th17 responses to prevent TB disease.

immunology↗

Control of Mycobacterium tuberculosis Infection in Lungs is Associated with Recruitment of Antigen-Specific Th1 and Th17 cells Co-expressing CXCR3 and CCR6.

Mycobacterium tuberculosis (Mtb)-specific T cell responses associated with immune control during asymptomatic latent tuberculosis infection (LTBI) remain poorly understood. Using a non-human primate (NHP) aerosol model, we studied the kinetics, phenotypes and functions of Mtb antigen-specific T cells in peripheral and lung compartments of Mtb-infected asymptomatic rhesus macaques by longitudinally sampling blood and bronchoalveolar lavage (BAL), for up to 24 weeks post-infection. We found significantly higher frequencies of Mtb-specific effector and memory CD4 and CD8 T cells producing IFN-{gamma} in the airways compared to peripheral blood, which were maintained throughout the study period. Moreover, Mtb-specific IL-17+ and IL-17/IFN-{gamma} double-positive T cells were present in the airways but were largely absent in the periphery, suggesting that balanced mucosal Th1/Th17 responses are associated with LTBI. The majority of Mtb-specific CD4 T cells that homed to the airways expressed the chemokine receptor CXCR3 and co-expressed CCR6. Notably, CXCR3+CD4+ cells were found in granulomatous and non-granulomatous regions of the lung and inversely correlated with Mtb burden. Our findings provide novel insights into antigen-specific T cell responses associated with asymptomatic Mtb infection that are relevant for developing better strategies to control TB.

immunology↗