Project description:Background: M.tuberculosis is one of the most prevalent and deadly human pathogens. The molecular mechanisms determining the outcomes of an infection with M.tuberculosis, that range from resistance to an active progressive disease, remain incompletely understood. Here we provide the evidence that IL-1alpha plays a critical and non-redundant role in enabling host resistance to pulmonary M.tuberculosis infection in mice that develop functional pathogen-specific adaptive immunity. Mechanistically, IL-1alpha-deficient mice fail to control M.tuberculosis replication in vivo at a level of individual infected cells and succumb to progressive disease at the late phase of infection. Furthermore, we show that IL-1alpha from hematopoietic compartment through IL-1RI operates upstream of TNFRI-signaling pathway and the lack of IL-1alpha leads to the continuous influx of monocytes that acquire a hyper-inflammatory phenotype and contribute to pathology, rather than to a pathogen control. Cell-type-specific restoration of IL-1alpha expression in CD11c+ subsets of lung leukocytes resulted in reduced levels of inflammatory marker expression on lung cells and improved survival IL-1alpha-deficient mice after M.tuberculosis infection. In humans, genetic analysis of single nucleotide polymorphisms in 14 genes implicated in IL-1-IL-1R signaling pathway revealed association of genetic variations in IL-1alpha and IL-1RAP genes with human susceptibility to pulmonary tuberculosis. Our results implicate IL-1alpha as a principal factor of host resistance to M.tuberculosis and IL-1alpha-driven cell-cell crosstalk as a key step in triggering M.tuberculosis control mechanisms that are critical for host survival.
Project description:The cytokine IL-10 deactivates macrophages and has been shown to impair resistance to mycobacterial infection. We have infected transgenic mice overexpressing IL-10 under control of the macrophage-specific CD68 promoter (macIL-10tg mice) with Mycobacterium tuberculosis by aerosol and found increased bacterial loads in the lungs of macIL-10tg mice. To identify programs of genes regulated by IL-10 and associated with increased mycobacterial replication, genome-wide expression analysis was performed. Experiment Overall Design: Impact of IL-10 pulmonary gene expression in mouse M. tuberculosis infection
Project description:Host resistance to Mycobacterium tuberculosis (Mtb) infection requires the activities of multiple leukocyte subsets, yet the roles of the different innate effector cells during tuberculosis (TB) are incompletely understood. Here we show a role for eosinophils in host resistance to Mtb infection. In humans, eosinophils are found in resected human TB lung lesions and autopsy granulomas. Eosinophils are also found in granulomas in zebrafish, mice, and non-human primates, where they are functionally activated and degranulate. Transcriptional profiling of lung tissue after Mtb infection of mice, that selectively lack eosinophils, revealed changes in neuronal associated pathways. Importantly, employing several independent models of eosinophil deficiency in mice, we demonstrate that eosinophils are required for optimal pulmonary bacterial control and host survival after Mtb infection. Collectively, our findings establish an unexpected role for eosinophils, granulocytes typically associated with type II inflammation, in host resistance against Mtb, a major human bacterial pathogen.
Project description:The treatment of Mycobacterium avium (Mav) infection, responsible for over 80% of non-tuberculous mycobacterial pulmonary disease, remains challenging due to rising antibiotic resistance and unsatisfactory success rates. Hence, there is a need for a deeper understanding of host–pathogen interactions to inform the development of alternative therapeutic approaches, like host-directed therapy (HDT), aimed at improving host antimycobacterial defenses.. However, compared to Mycobacterium tuberculosis (Mtb) infections, knowledge of host-pathogen interactions for Mav infection is still limited. To address this knowledge gap, we performed a genome-wide host transcriptomic analysis of Mav-infected primary human macrophages —the primary host cell—alongside Mtb-infected macrophages to leverage insights from Mtb research. Our findings show substantial overlap in the gene expression patterns between Mav-infected and Mtb-infected macrophages, including induction of cytokine responses and modulation of various G-protein coupled receptors (GPCRs) involved in (lipid-mediated) macrophage immune functions. Notable differences were observed in nerve growth factor (NGF) signaling and genes of the GTPase of immunity-associated protein (GIMAP) family. This study laid a foundation for identifying both shared and Mav‑specific host response pathways, providing direction for future investigations into host-pathogen interactions during Mav infection and the identification of novel targets for HDT.
Project description:Pyrazinamide (PZA) is one of the first line antibiotics used for the treatment of tuberculosis (TB). we have used human monocyte and a mouse model of pulmonary TB to investigate whether treatment with PZA, in addition to its known anti-mycobacterial properties, modulate the host immune response during Mycobacterium tuberculosis (Mtb) infection.
Project description:Using cell-based approaches and experimental mouse models for pulmonary TB we unveiled MDSCs as new myeloid populations directly interacting with Mycobacterium tuberculosis (Mtb). MDSCs readily phagocytosed Mtb, released proinflammatory (IL-6, IL-1α) and immunomodulatory (IL-10) cytokines while retaining their suppressive capacity. MDSCs were identified at the site of infection in disease-resistant and -susceptible mice during pulmonary TB. Excessive MDSC accumulation in lungs correlated with elevated surface expression of IL-4Rα and heightened TB lethality.
Project description:Exposure to cigarette smoke (CS) is a known risk factor for pulmonary tuberculosis, and smokers are at increased risk of treatment failure and relapse. Using differentiated primary human bronchial epithelial cells (PBEC), we studied whether there is a direct effect of acute CS exposure on epithelial host responses to infection with Mycobacterium tuberculosis (Mtb) and Mycobacterium avium (Mav). The study population included 8 individual donors, of whom 4 were female. Median age was 66.5 years (range 56-70). Of these donors, none were current smokers, 5 were ex-smokers (62.5%), 2 were non-smokers (25%) and no information was available for 1 donor (12.5%). None of the donors were diagnosed with chronic obstructive pulmonary disease.
Project description:Host-pathogen interactions in Mycobacterium tuberculosis infection still remain poorly understood. We investigated the host immune response to different reference Mycobacterium tuberculosis strains in THP-1 cells. Major differences in the gene expression profiles were identified in response to infection with these strains. These findings shed new insights into the dynamic variation in tuberculosis immune response and pathogenesis. We used Affymetrix GeneChip Human Exon 1.0 ST microarrays to investigate host differential gene expression in response to different Mycobacterium tuberculosis strains.
Project description:Using cell-based approaches and experimental mouse models for pulmonary TB we unveiled MDSCs as new myeloid populations directly interacting with Mycobacterium tuberculosis (Mtb). MDSCs readily phagocytosed Mtb, released proinflammatory (IL-6, IL-1M-NM-1) and immunomodulatory (IL-10) cytokines while retaining their suppressive capacity. MDSCs were identified at the site of infection in disease-resistant and -susceptible mice during pulmonary TB. Excessive MDSC accumulation in lungs correlated with elevated surface expression of IL-4RM-NM-1 and heightened TB lethality. Microarray experiments were performed as dual-color hybridizations on Agilent mouse whole genome catalog 44K arrays. To compensate for dye-specific effects, a dye-reversal color-swap was applied.
Project description:Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a significant global health burden, characterized by complex host–pathogen interactions that drive heterogeneous clinical outcomes. While pulmonary epithelial cells are increasingly recognized as active participants in innate immunity during Mtb infection, how host defences are altered when the epithelial barrier is compromised remains unclear . In this study, we developed a murine model combining naphthalene-induced airway epithelial injury with Mtb infection, and found a pronounced impairment in pulmonary bacterial clearance. Through single-cell RNA sequencing (scRNA-seq), we mapped the pulmonary cells landscape and identified widespread suppression of epithelial immune functions. Notably, we observed macrophages transition from an antimicrobial to an antigen-presenting phenotype, indicating waning pulmonary innate defenses and heightened adaptive immune activation. These findings highlight the pivotal role of pulmonary epithelial integrity in shaping host immunity against Mtb and offer new insights into potential therapeutic strategies targeting barrier–immune crosstalk.