ABSTRACT: COPD-Specific Gene Expression Signatures of Alveolar Macrophages as well as Peripheral Blood Monocytes Overlap and Correlate with Lung Function
Project description:COPD-Specific Gene Expression Signatures of Alveolar Macrophages as well as Peripheral Blood Monocytes Overlap and Correlate with Lung Function
Project description:Despite their importance in lung health and disease, it remains unknown how human alveolar macrophages develop early in life. In this study we identified the fetal progenitor of human alveolar macrophages. We used microarray to define the gene signatures of human CD14+ blood monocytes (adult AM precursors), CD116+CD64+ fetal liver monocytes, and CD116+CD64- fetal AM precursors.
Project description:Rationale: Chronic Obstructive Pulmonary Disease (COPD) is considered a chronic inflammatory disease characterized by progressive airflow limitation and also has significant extrapulmonary (systemic) effects that lead to comorbid conditions. Very little is known about the pathomechanism of the disease. Objectives: Among inflammatory cell types, alveolar macrophages appear to have a key role in initiating and/or sustaining disease progression. These cells are derived from peripheral monocytes. Identification of disease and cell type specific gene expression profiles can be revealing and also practically useful in order to diagnose and characterize disease progression and the effect of drug treatment. Methods: We used Affymetrix microarrays to obtain gene expression data of alveolar macrophages and circulating monocytes of COPD and healthy control patients. The microarray results were confirmed by quantitative real-time polymerase chain reaction in multiple patient collections. Measurements and Main Results: We have identified gene sets specifically associated with COPD in alveolar macrophages and also in monocytes. Immune function, responses to stimuli, and cell death related genes appear to be impacted in both cell types. Remarkably, there is an overlapping gene set between the two cell types. Conclusions: Taken together, our data show that COPD-specific gene signatures can be identified and validated, and that the disease also affects peripheral monocytes. Moreover, monocytes and alveolar macrophages carry overlapping gene expression signatures. Our findings further support the notion that altered responsiveness to stimuli is the key characteristic of alveolar macrophages and also of their precursors, peripheral monocytes. Brochoalveolar lavage fluid samples were collected from of COPD and healthy control patients. Alveolar macrophages were isolated using Percoll gradient centrifugation, isolated using CD14+ magnetic beads, and total RNA was extracted using Qiagen RNeasy Kit. The monocyte samples represent a pool of RNA from 5 patients. Total RNA was labeled with biotin and individual samples were hybridized to Affymetrix HG U133A GeneChips. Affymetrix data files were analyzed using GeneSpring 7.3 software. Using a non-parametric statistical test, we compared the gene expression patterns of the COPD and the healthy control patients and identified a set a genes that showed differential expression between the two groups.
Project description:Rationale: Chronic Obstructive Pulmonary Disease (COPD) is considered a chronic inflammatory disease characterized by progressive airflow limitation and also has significant extrapulmonary (systemic) effects that lead to comorbid conditions. Very little is known about the pathomechanism of the disease. Objectives: Among inflammatory cell types, alveolar macrophages appear to have a key role in initiating and/or sustaining disease progression. These cells are derived from peripheral monocytes. Identification of disease and cell type specific gene expression profiles can be revealing and also practically useful in order to diagnose and characterize disease progression and the effect of drug treatment. Methods: We used Affymetrix microarrays to obtain gene expression data of alveolar macrophages and circulating monocytes of COPD and healthy control patients. The microarray results were confirmed by quantitative real-time polymerase chain reaction in multiple patient collections. Measurements and Main Results: We have identified gene sets specifically associated with COPD in alveolar macrophages and also in monocytes. Immune function, responses to stimuli, and cell death related genes appear to be impacted in both cell types. Remarkably, there is an overlapping gene set between the two cell types. Conclusions: Taken together, our data show that COPD-specific gene signatures can be identified and validated, and that the disease also affects peripheral monocytes. Moreover, monocytes and alveolar macrophages carry overlapping gene expression signatures. Our findings further support the notion that altered responsiveness to stimuli is the key characteristic of alveolar macrophages and also of their precursors, peripheral monocytes.
Project description:The impact of cell origin on human lung macrophage identity and function remains unknown. In this study we characterized human alveolar macrophages of fetal versus adult origin. We used microarray to define the gene signatures of human alveolar macrophages derived from CD116+CD64+ fetal monocytes, CD116+CD64- fetal precursors, and CD34+ HSPCs in MISTRG humanized mice.
Project description:We developed a simplified flow cytometry strategy in order to discriminate monocytes and macrophages in the lung of C57BL/6 mice. Using this strategy, we identified autofluorescent F4/80+ CD11c+ alveolar macrophages, non-autofluorescent CD64+Ly-6C- interstitial macrophages and Ly-6Chi monocytes residing in the lung of WT mice. A fraction of these Ly-6Chi monocytes corresponded to classical blood monocytes associated with the lung vasculature, but another fraction did not depend on CCR2, the chemokine receptor required for monocytes to egress from the bone marrow, as a population of lung Ly-6Chi monocytes was also present in the lung of Ccr2-/- mice. A remaining question was whether lung monocytes represented a particular population of monocytes that could be distinguishable from the classical CCR2-dependent blood monocytes. To address this issue, we performed a transcriptomic comparison of Ly-6Chi monocytes recovered from flushed lung of WT mice (â60% of CCR2- dependent classical blood monocytes and â40% of lung monocytes) and Ccr2-/- mice (more than 95% of lung monocytes). In addition, we tested whether exposure to TLR ligands would affect interstitial macrophages, and we compared to transcriptome of IM at steady-state and IM 1 week after administration of 50 µg CpG-DNA intratracheally.
Project description:We sought to evaluate in an unbiased way the heterogeneity of lung interstitial macrophages and their relationship with alveolar macrophages, lung Ly-6Chi classical monocytes and Ly-6Clo patrolling monocytes, by single cell RNA-Seq.
Project description:Aim of this project was to examine the global gene expression profiles of mononuclear phagocytes recruited from peripheral blood to the alveolar space following alveolar deposition of the TLR2-ligand Pam3CSK4 in transgenic CX3CR1+/GFP mice. Experiment Overall Design: Alveolar macrophages (AM) and peripheral blood monocytes (PBM) were isolated from broncho-alveolar lavages and from blood, respectively, using FACS. Expression profiles from AM and PBM of the same mice were compared on the same slides. Each labeled RNA sample contained RNA pooled from six individuals. Four pairs of RNA from corresponding AM and PBM pools were hybridized, giving a total amount of 24 individual mice analyzed. Two hybridizations were performed with AM labeled with Cy3 and PBM with Cy5, two hybridizations were performed with swaped dyes.
Project description:In this study we demonstrate that the lung mononuclear phagocyte system comprises three interstitial macrophages (IMs), as well as alveolar macrophages (AMs), dendritic cells and few extravascular monocytes. Through cell sorting and RNAseq analysis we were able to identify transcriptional similarities and differences between the three pulmonary IM subtypes, with reference to the more well-characterized alveolar macrophage
Project description:Acute inflammatory exacerbations (AIE) represent precipitous deteriorations of a number of chronic lung conditions, including pulmonary fibrosis (PF), chronic obstructive pulmonary disease and asthma. AIEs are marked by diffuse and persistent polycellular alveolitis that profoundly accelerate lung function decline and mortality. In particular, excess monocyte mobilization during AIE and their persistence in the lung have been suggested to be linked to poor disease outcome. We have developed a mutant model of pulmonary fibrosis leveraging the PF-linked missense isoleucine to threonine substitution at position 73 [I73T] in the alveolar type-2 cell-restricted Surfactant Protein-C [SP-C] gene [SFTPC]. With this toolbox at hand, the present work investigates the dynamics of resident alveolar macrophages and peripheral monocytes during the initiation and progression of AIE-PF. FACS analysis of SigF+CD11b- alveolar macrophages and Ly6Chi monocytes isolated 3 d and 14 d after SP-CI73T injury and performed RNA sequencing. Pathway and gene expression analysis revelaed dynamic transcriptional changes associated with “Innate Immunity’ and ‘Extracellular Matrix Organization’ signaling. Supported by previous pharmacological evidence, genetic ablation of CCR2+ monocytes (SP-CI73TCCR2KO) resulted in improved lung histology, mouse survival, and reduced inflammation compared to SP-CI73TCCR2WT cohorts. Immunohistochemical and in situ hybridization analysis revealed comparable levels of tgfb1 mRNA expression localized primarily parenchymal cells found nearby foci of injury. Our results also confirmed reduced inflammatory activation (iNOS, Arg1) in SP-CI73TCCR2KO lungs as well as partial colocalization of tgfb1 mRNA expression in Arg1+ cells. These results provide a detailed picture on the role of resident macrophages and recruited monocytes in the context of AIE-PF driven by alveolar epithelial dysfunction.