Project description:There is an increasing appreciation for the heterogeneity of myeloid lineages in the lung, but relatively little is known about populations specifically associated with the conducting airways. We use single-cell RNA sequencing, flow cytometry, and immunofluorescence to characterize myeloid cells of the mouse trachea during homeostasis and epithelial injury/repair. We identify submucosal macrophages, similar to lung interstitial macrophages, and intraepithelial macrophages. Following injury, there are early increases in neutrophils and submucosal macrophages, including M2-like macrophages. Intraepithelial macrophages are lost after injury and later restored by CCR2+ monocytes. We show that repair of the tracheal epithelium is impaired in Ccr2-deficient mice. Mast cells and group 2 innate lymphoid cells are sources of interleukin-13 (IL-13) that polarize macrophages and directly influence basal cell behaviors. Their proximity to the airway epithelium establishes these myeloid populations as potential therapeutic targets for airway disease.
Project description:We isolated CD45+ cells after injury (Uninjured, Day1, Day4 and Day7) and CD45+F4/80+ cells from tracheal mesenchyme and dissociated lung, as well as CD45+ cells from peeled tracheal epithelium.
Project description:Airway macrophages (AMs) are the most abundant leukocytes in the healthy airway lumen and have a highly specialised but plastic phenotype that is governed by the local microenvironment. AMs are thought to maintain immunological homeostasis in the steady state, but have also been implicated in the pathogenesis of allergic airway disease (AAD). To better understand these potentially contrasting AM functions, bulk RNA sequencing was performed on murine AMs obtained during experimental AAD driven by repeated house dust mite inhalation (AM[HDM]s), comparing to control AMs from non-allergic mice. AM[HDM]s showed increased expression of genes associated with antigen presentation, inflammatory cell recruitment and tissue repair, including several chemokines and matrix metalloproteinases. This was accompanied by increased expression of mitochondrial electron transport chain subunit genes and the retinoic acid biosynthetic enzyme gene Raldh2. Conversely, AM[HDM]s displayed decreased expression of a number of cell cycle genes, genes related to cytoskeletal functions and a subset of genes implicated in antimicrobial innate immunity, such as Tlr5, Il18 and Tnf. Differential gene expression in AM[HDM]s was consistent with upstream effects of the cytokines IL-4 and IFN-γ, both of which were at increased concentrations in lung tissue after HDM treatment. These data highlight diverse gene expression changes in the total AM population in a clinically relevant mouse model of AAD, overall suggestive of contributions to inflammation and tissue repair/remodelling, but decreases in certain steady state cellular and immunological functions.
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:Understanding the way in which the airway heals in response to injury is fundamental to dissecting the mechanisms underlying airway disease pathology. Only limited data is available in relation to in vivo characterisation of the molecular features of repair in the airway. This study sought to characterise the dynamic changes in gene expression that are associated with airway repair in response to physical injury. Gene expression changes in the airway wall following bronchial brush biopsy were profiled in anaesthetised sheep. The experimental design featured sequential studies in the same animals (n=8) over the course of a week and yielded data relating to the repair process at 6 hours, and 1, 3 and 7 days after injury. Notable features of the transcriptional response included the early and sustained preponderance of down-regulated genes associated with angiogenesis and immune cell activation, selection and differentiation. Later features of the repair response included the up-regulation of cell cycle genes at d1 and d3, and the later pronounced up-regulation of extracellular matrix-related genes at d3 and d7. It is possible to follow the process of airway wall repair in response to physical injury in the same animal over the course of time. Transcriptional changes featured coordinate expression of functionally related genes in a reproducible manner both within and between animals. This characterisation will provide a foundation against which to assess the perturbations that accompany airway disease pathologies of comparative relevance. Keywords: response to airway injury Each sheep was subjected to a protocol which involved the procedure of endobronchial brush biopsy (BBr) being performed, under anaesthesia, on three occasions, with two separate airway sites being subjected to brushing on each occasion. Two sheep were subjected to BBr seven days, three days and six hours prior to euthanasia, two sheep at seven days, three days and one day prior to euthanasia, two sheep at seven days, one day and six hours prior to euthanasia and two sheep at three days, one day and six hours prior to euthanasia. At post mortem examination (PME) each time point was therefore represented by material derived from six sheep. Airway tissue from a naM-CM-/ve site (from a segment not subjected to BBr) was also collected from each sheep at necropsy.
Project description:Tissue resident macrophages in the mammary gland are found in close association with epithelial structures and within the adipose stroma, and are important for mammary gland development and tissue homeostasis. While epithelial-associated macrophages have been linked to ductal development, the contributions of stromal macrophages to mammary gland homeostasis remain unknown. Using transcriptional profiling, we identify a distinct resident stromal macrophage subpopulation that is characterized by expression of Lyve-1, a receptor for the extracellular matrix component hyaluronan. This subpopulation is enriched in genes associated with extracellular matrix remodeling and is found to be specifically associated with hyaluronan-rich regions within the mammary stroma. Furthermore, macrophage depletion leads to increased accumulation of hyaluronan-associated extracellular matrix in the mammary stroma. These results demonstrate the presence of a distinct subpopulation of macrophages and provide insights into the functional contributions of these macrophages to stromal homeostasis in the mammary gland.
Project description:Understanding the way in which the airway heals in response to injury is fundamental to dissecting the mechanisms underlying airway disease pathology. Only limited data is available in relation to in vivo characterisation of the molecular features of repair in the airway. This study sought to characterise the dynamic changes in gene expression that are associated with airway repair in response to physical injury. Gene expression changes in the airway wall following bronchial brush biopsy were profiled in anaesthetised sheep. The experimental design featured sequential studies in the same animals (n=8) over the course of a week and yielded data relating to the repair process at 6 hours, and 1, 3 and 7 days after injury. Notable features of the transcriptional response included the early and sustained preponderance of down-regulated genes associated with angiogenesis and immune cell activation, selection and differentiation. Later features of the repair response included the up-regulation of cell cycle genes at d1 and d3, and the later pronounced up-regulation of extracellular matrix-related genes at d3 and d7. It is possible to follow the process of airway wall repair in response to physical injury in the same animal over the course of time. Transcriptional changes featured coordinate expression of functionally related genes in a reproducible manner both within and between animals. This characterisation will provide a foundation against which to assess the perturbations that accompany airway disease pathologies of comparative relevance. Keywords: response to airway injury
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.