Project description:Disparate Oxidant-related Gene Expression of Human Small Airway Epithelium Compared to Autologous Alveolar Macrophages in Response to the In Vivo Oxidant Stress of Cigarette Smoking The oxidant burden of cigarette smoking induces lung cell dysfunction, and play a significant role in the pathogenesis of lung disease. Two cell populations directly exposed to the oxidants in cigarette smoke are the small airway epithelium and alveolar macrophages. Of these, the epithelium appears to be more vulnerable to smoking, becoming disordered in differentiation, repair and function, while alveolar macrophages become activated, without becoming diseased. In this context, we asked: for the same individuals, what is the baseline trancriptome of oxidant-related genes in small airway epithelium compared to alveolar macrophages and do the responses of the transcriptome of these 2 cell populations differ substantially to inhaled cigarette smoke? To address these questions we used microarray gene expression and TaqMan analysis to assess the gene expression profile of known oxidant-related genes in paired samples recovered by bronchoscopy from small airway epithelium and alveolar macrophages from the same healthy nonsmokers and normal smokers. Of the 155 oxidant-related genes surveyed, 122 (77%) were expressed in both cell populations in nonsmokers. However, of the genes expressed by both cell populations, oxidant related gene expression levels were higher in alveolar macrophages (67 genes, 43%) than small airway epithelium (37 genes, 24%). There were more oxidant-related genes uniquely expressed in the small airway epithelium (17%), than in alveolar macrophages (5%). In healthy smokers, the majority of oxidant-related genes were expressed in both cell populations, but there were marked differences in the numbers of oxidant-related genes that smoking up- or down-regulated. While smoking up-regulated 15 genes (10%) and down-regulated 7 genes (5%) in the small airway epithelium, smoking had far less effect on alveolar macrophages [only 4 (3%) genes up-regulated, and only 1 (0.6%) down-regulated]. Only a small number of smoking responsive oxidant-related genes overlapped between the two cell types (2 up-regulated, and no down-regulated genes). Consistent with this observation, pathway analysis of smoking-responsive genes in the small airway epithelium showed oxidant-related pathways dominated, but in alveolar macrophages immune-response pathways dominated. Thus, the responses of the oxidant-related transcriptome of cells with an identical genome and exposed to the same oxidant stress of cigarette smoking are very different, with responses of oxidant-related genes of alveolar macrophages far more subdued than that of small airway epithelium, consistent with the clinical observation that, while the small airway epithelium is vulnerable, alveolar macrophages are not "diseased" in response to the oxidant stress of cigarette smoking. Gene expression profiles of known oxidant-related genes in paired samples recovered by bronchoscopy from small airway epithelium and alveolar macrophages from the same healthy nonsmokers and normal smokers.
Project description:Infants are vulnerable to disseminated forms of tuberculosis and suffer disproportionately high morbidity and mortality, but the reasons for this are unknown. We hypothesized that since alveolar macrophages (AMs) are critical in the uptake and containment of Mycobacterium tuberculosis (Mtb) in the lung, their function may be impaired in early life. We developed a method of obtaining AMs during rigid bronchoscopy of healthy infants with suspected airway abnormality. RNAseq analysis of Mtb-stimulated AMs from 4 infants and 4 adults was performed.
Project description:A potent Th1 immune response is critical to the control of tuberculosis. The impact of an additive Th2 response on the course of disease has so far been insufficiently characterized, despite increased morbidity after coinfection with Mycobacterium tuberculosis and Th2 eliciting helminths and possible involvement of Th2 polarization in reactivation of latent tuberculosis. Here, we describe the gene expression profile of murine bone marrow derived macrophages alternatively activated by IL-4 to infection with M. tuberculosis. Comparison of transcriptional profiles of infected IL-4 and IFN-g activated macrophages revealed delayed and partially diminished responses in alternatively activated macrophages, characterized by reduced exposure to nitrosative stress and increased iron availability, respectively, to intracellular bacteria. Alternative activation of host macrophages correlated with elevated expression of the M. tuberculosis iron storage protein bfrB as well as reduced expression of the mycobactin synthesis genes mbtI and mbtJ. The extracellular matrix remodelling enzyme matrix metalloproteinase-12 (MMP-12) was induced in alternatively activated macrophages in vitro, and MMP-12 expressing macrophages were abundant at late, but not early, stages of tuberculosis in murine lungs. Our findings emphasize that alternative activation deprives macrophages of control mechanisms which limit mycobacterial growth in vivo, thus supporting intracellular persistence of M. tuberculosis. Keywords: transcriptome, gene regulation, macrophages, IL-4, IFN-gamma, nitric oxide
Project description:Disparate Oxidant-related Gene Expression of Human Small Airway Epithelium Compared to Autologous Alveolar Macrophages in Response to the In Vivo Oxidant Stress of Cigarette Smoking The oxidant burden of cigarette smoking induces lung cell dysfunction, and play a significant role in the pathogenesis of lung disease. Two cell populations directly exposed to the oxidants in cigarette smoke are the small airway epithelium and alveolar macrophages. Of these, the epithelium appears to be more vulnerable to smoking, becoming disordered in differentiation, repair and function, while alveolar macrophages become activated, without becoming diseased. In this context, we asked: for the same individuals, what is the baseline trancriptome of oxidant-related genes in small airway epithelium compared to alveolar macrophages and do the responses of the transcriptome of these 2 cell populations differ substantially to inhaled cigarette smoke? To address these questions we used microarray gene expression and TaqMan analysis to assess the gene expression profile of known oxidant-related genes in paired samples recovered by bronchoscopy from small airway epithelium and alveolar macrophages from the same healthy nonsmokers and normal smokers. Of the 155 oxidant-related genes surveyed, 122 (77%) were expressed in both cell populations in nonsmokers. However, of the genes expressed by both cell populations, oxidant related gene expression levels were higher in alveolar macrophages (67 genes, 43%) than small airway epithelium (37 genes, 24%). There were more oxidant-related genes uniquely expressed in the small airway epithelium (17%), than in alveolar macrophages (5%). In healthy smokers, the majority of oxidant-related genes were expressed in both cell populations, but there were marked differences in the numbers of oxidant-related genes that smoking up- or down-regulated. While smoking up-regulated 15 genes (10%) and down-regulated 7 genes (5%) in the small airway epithelium, smoking had far less effect on alveolar macrophages [only 4 (3%) genes up-regulated, and only 1 (0.6%) down-regulated]. Only a small number of smoking responsive oxidant-related genes overlapped between the two cell types (2 up-regulated, and no down-regulated genes). Consistent with this observation, pathway analysis of smoking-responsive genes in the small airway epithelium showed oxidant-related pathways dominated, but in alveolar macrophages immune-response pathways dominated. Thus, the responses of the oxidant-related transcriptome of cells with an identical genome and exposed to the same oxidant stress of cigarette smoking are very different, with responses of oxidant-related genes of alveolar macrophages far more subdued than that of small airway epithelium, consistent with the clinical observation that, while the small airway epithelium is vulnerable, alveolar macrophages are not "diseased" in response to the oxidant stress of cigarette smoking.
Project description:Macrophages play an essential role in the early immune response to Mycobacterium tuberculosis and are the cell type preferentially infected in vivo. Primary macrophages and macrophage-like cell lines are commonly used as infection models, although the physiological relevance of cell lines, particularly for host-pathogen interaction studies, is debatable. Here we use high-throughput RNA-sequencing to analyse transcriptome dynamics of two macrophage models in response to M. tuberculosis infection. Specifically, we study the early response of bone marrow-derived mouse macrophages and cell line J774 to infection with live and -irradiated (killed) M. tuberculosis. We show that infection with live bacilli specifically alters the expression of host genes such as RSAD2, IFIT1/2/3 and RIG-I, whose potential roles in resistance to M. tuberculosis infection have not yet been investigated. In addition, the response of primary macrophages is faster and more intense than that of J774 cells in terms of number of differentially expressed genes and magnitude of induction/repression. Our results point to potentially novel processes leading to immune containment early during M. tuberculosis infection, and support the idea that important differences exist between primary macrophages and cell lines, which should be taken into account when choosing a macrophage model to study host-pathogen interactions.
Project description:Mycobacterium tuberculosis is an intracellular human pathogen with the ability to resist and adapt to many adverse conditions it encounters upon infection. Among these, overcoming the production of nitric oxide by macrophages could be key for M. tuberculosis success. We have challenged M. tuberculosis with a sub-lethal concentration of nitric oxide and followed the transcriptomic response through RNA-seq for 48 hours.
Project description:Mycobacterium tuberculosis (Mtb) infects alveolar macrophages (AMs) causing pulmonary tuberculosis (PTB), the more frequent form of the disease. Less frequently, Mtb disseminates to many other organs and tissues resulting in different extrapulmonary forms of TB. Nevertheless, very few studies have addressed the global mRNA response of human AMs, in particular from humans with the active form of the disease. Strikingly, almost no studies have addressed the response to infection with Mtb by human extrapulmonary macrophages.
Project description:Analysis of Mtb infected murine macrophages derived from C57Bl/6 WT, TPL2KO, IFNARKO & TPL2IFNAR DKO mice [Set 1] Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), remains a leading cause of mortality and morbidity worldwide, causing approximately 1.4 million deaths per year. Key immune components for host protection during tuberculosis include the cytokines IL?12, IL?1 and TNF??, as well as IFN?? and CD4+ Th1 cells. However, immune factors determining whether individuals control infection or progress to active tuberculosis are incompletely understood. Excess amounts of type I interferon have been linked to exacerbated disease during tuberculosis in mouse models and to active disease in patients, suggesting tight regulation of this family of cytokines is critical to host resistance. In addition, the immunosuppressive cytokine IL?10 is known to inhibit the immune response to Mtb in murine models through the negative regulation of key pro-inflammatory cytokines and the subsequent Th1 response. We show here, using a combination of transcriptomic analysis, genetics and pharmacological inhibitors that the TPL-2-ERK1/2 signaling pathway is important in mediating host resistance to tuberculosis through negative regulation of type I interferon production. The TPL-2-ERK1/2 signalling pathway regulated production by macrophages of several cytokines important in the immune response to Mtb as well as regulating induction of a large number of additional genes, many in a type I IFN dependent manner. In the absence of TPL-2 in vivo, excess type I interferon promoted IL-10 production and exacerbated disease. These findings describe an important regulatory mechanism for controlling tuberculosis and reveal mechanisms by which type I interferon may promote susceptibility to this important disease. Macrophages were derived from C57Bl/6 bone marrow, plated and infected with Mtb H37Rv (or not) in duplicate wells. Samples were then harvested for RNA at time 0 (uninfected only), 15m, 30m, 1hr, 3hr, 6hr and 24hr.
Project description:During tuberculosis, lung myeloid cells have two opposing roles: they are an intracellular niche occupied by Mycobacterium tuberculosis and they restrict bacterial replication. Lung myeloid cells from mice infected with yellow-fluorescent protein expressing M. tuberculosis mice were analyzed by flow cytometry and transcriptional profiling to identify the cell types infected and their response to infection. CD14, CD38, and Abca1 were expressed more highly by infected alveolar macrophages and CD11cHi monocyte-derived macrophages compared to uninfected cells. CD14, CD38, and Abca1 “triple positive” (TP) cells had incomparably high infection rates and bacterial loads, but also a strong interferon-γ signature and nitric oxide synthetase-2 production indicating recognition by T cells. Despite evidence of T cell recognition and appropriate activation, these TP+ macrophages became the dominant niche occupied by M. tuberculosis long-term. Defining this niche should help answer why M. tuberculosis resists elimination from activated macrophages even in the face of T cell immunity.