ABSTRACT: Alveolar macrophages (AMs) in patients with chronic obstructive pulmonary disease (COPD) orchestrate persistent inflammation in the airway, however, sub-populations of alveolar macrophages predominantly participating in chronic inflammation have been poorly characterised. We recently reported that Siglec-1 was involved in recognition and engulfment of non-typeable Haemophilus influenzae and that the expression of Siglec-1 on AMs was decreased in COPD lung tissues. Here, based on the expression of Siglec-1 and the intensity of forward scattergram (FSC) using flow cytometry, we identified three subsets present in alveolar macrophages: Siglec-1+/FSChi, Siglec-1−/FSChi, Siglec-1−/FSClow subsets. The Siglec-1−/FSClow subset increased in number in the lungs of COPD subjects. RNA-sequencing revealed that the Siglec-1−/FSClow subset exhibited pro-inflammatory and protease-producing phenotypes compared to other two subsets. Clinically, a decrease in the intensity of Siglec-1 expression in macrophages of induced sputum from COPD subjects was correlated with exacerbation rates in prospective four years. Collectively Siglec-1− AMs showed the pro-inflammatory properties and that their emergence in COPD airways was a risk factor in exacerbation. The Siglec-1−/FSClow subset might serve as “pathogenic macrophages” which could lead to poor clinical outcomes for patients with COPD
Project description:Acquisition of a new strain of non-typeable Haemophilus influenzae (NTHi) is often associated with exacerbation of chronic obstructive pulmonary disease (COPD). We have previously reported that COPD patients who are homozygous null for SIGLEC14 gene is less susceptible to COPD exacerbation than those who have wild-type allele with functional SIGLEC14 gene. In order to gain insight into the mechanism behind the COPD exacerbation, and to find new clues that may lead to the discovery of objective biomarker of COPD exacerbation, Siglec-14/THP-1 and Siglec-5/THP-1 cell lines, which mimic monocytes from homozygous wild-type and homozygous SIGLEC14-null person, respectively, were incubated with or without NTHi, and their gene expression profiles were compared by using Affymetrix Human Genome U133 Plus 2.0 Array. Four samples (2 cell lines x 2 conditions) were analyzed. No replicates were made.
Project description:Acquisition of a new strain of non-typeable Haemophilus influenzae (NTHi) is often associated with exacerbation of chronic obstructive pulmonary disease (COPD). We have previously reported that COPD patients who are homozygous null for SIGLEC14 gene is less susceptible to COPD exacerbation than those who have wild-type allele with functional SIGLEC14 gene. In order to gain insight into the mechanism behind the COPD exacerbation, and to find new clues that may lead to the discovery of objective biomarker of COPD exacerbation, Siglec-14/THP-1 and Siglec-5/THP-1 cell lines, which mimic monocytes from homozygous wild-type and homozygous SIGLEC14-null person, respectively, were incubated with or without NTHi, and their gene expression profiles were compared by using Affymetrix Human Genome U133 Plus 2.0 Array.
Project description:Chronic obstructive pulmonary disease (COPD) is currently the fourth leading cause of morbidity and mortality in the world and is predicted to be the third leading cause of death. It is characterized by chronic airway inflammation, lung destruction and remodeling, resulting in irreversible airflow obstruction. We utilized single cell RNA-sequencing (scRNA-Seq) to identify ferroptotic differences and associated biological processes involved in the pathogenesis of COPD. We performed scRNA-Seq on lung tissue obtained from donors with non-COPD and mild-to-moderate COPD to identify disease-related genes within different cell types. We identified two populations of alveolar macrophages (AMs) in the human lung that were dysregulated in COPD patients. We discovered that M2-like AMs modulate susceptibility to ferroptosis by disrupting lipid and iron homeostasis both in vivo and in vitro. The discrepancy in sensitivity to ferroptosis can be determined and regulated by HO-1. In contrast, M1-like AMs showed the ability to attenuate oxidative stress and exert resistance to ferroptosis. In addition, the expression of genes within M2-like AMs is also involved in defects in phagocytosis and lysosome distortion. Present scRNA-seq transcriptomic analysis provides a rich data source to further explore lung health and disease, and the development of therapeutic strategies specifically targeting ferroptosis-sensitive alveolar macrophages might be used to develop therapeutic targets..
Project description:Background: Metabolic plasticity involving shifts between mitochondrial respiration and glycolysis is emerging as a crucial component of efficient innate immune cell responses. Alveolar macrophages (AMs), the most abundant antigen-presenting cells in the lung, are dramatically increased in the lungs of patients with chronic obstructive pulmonary disease (COPD). However, COPD AMs exhibit dysfunctional responses to infection with lower phagocytic ability and impairment of mitochondrial reactive oxygen species (ROS) generation. Little is known about the mitochondrial function or respiration of these cells and whether alterations in their mitochondrial or glycolytic activities may contribute to the pathogenesis of COPD.
Project description:Macrophages (MΦ) have been shown to contribute to fibrogenesis, however the underlying mechanisms and specific MΦ subsets involved remain unclear. Lung MΦ can be divided into two subsets: Siglec-Fhi resident alveolar MΦ and CD11bhi MΦ that primarily arise from immigrating monocytes. RNA-seq analysis was performed to compare these MΦ subsets during fibrosis. CD11bhi MΦ, not Siglec-Fhi MΦ, expressed high levels of pro-fibrotic chemokines and growth factors.
Project description:Transcriptional profiling of primary human alveolar macrophages (AMs) comparing control untreated AMs with AMs exposed with Serotype 14 Streptococcus pneumoniae (NCTC11902) strain (MOI 10) for 4 hours) Two-condition experiment, control AMs vs. infected AMs. Biological replicates: 3 control replicates, 3 infected replicates MOI 10.
Project description:Macrophages are a major target for human immunodeficiency virus type 1 (HIV-1) infection. However, macrophages are largely heterogeneous and may exhibit differences in permissiveness to HIV-1 infection. This study highlights the interplay of macrophage heterogeneity in HIV-1 pathogenesis. We show that monocyte-derived macrophages (MDM) could be divided into two distinct subsets: CD14+Siglec-1hiCD4+ (non-adherent MDM), and CD14+Siglec-1LoCD4- (adherent MDM). The CD14+Siglec-1hiCD4+MDM subset represented the smaller proportion in the macrophage pool, and varied among different donors. Fractionation and subsequent exposure of the two MDM subsets to HIV-1 revealed opposite outcomes in terms of HIV-1 capture and infection. Although the CD14+Siglec-1hiCD4+MDM captured significantly more HIV-1, infection was significantly higher in the CD14+Siglec-1LoCD4-MDM subset. Thus, CD14+Siglec-1hiCD4+MDM were less permissive to infection. Depletion of CD14+Siglec-1hiCD4+MDM or a decrease in their percentage, resulted in increased infection of MDM, suggestive of a capacity of these cells to capture and sequester HIV-1 in an environment that hinders its infectivity. Increased expression of innate restriction factors and cytokine genes were observed in the non-adherent CD14+Siglec-1hiCD4+MDM, both before and after HIV-1 infection, compared to the adherent CD14+Siglec-1LoCD4-MDM. The differential expression of gene expression profiles in the two macrophage subsets may provide an explanation for the differences observed in HIV-1 infectivity.
Project description:Disseminated cancer cells reside in the lung alveolar niche where they are exposed to interactions with alveolar macrophages. Here we report singe-cell RNA-sequencing data of lung macrophages from MMTV-HER2 mice at the early stage (16-weeks) harboring single dormant cancer cells and late stage mice (32-weeks harboring metastatic lesions, as well as wildtype control mice. We discovered alveolar macrophage and interstitial macrophage subsets that change in expression profile and frequency between stages. We find majority of the AMs are homeostatic in phenotype, and emergence of inflammatory AM subsets in late-stage MMTV-HER2 mice.
Project description:The transcriptomes of FACS-sorted siglec-F+ alveolar macrophages and siglec-f- CD11b+ exudative macrophages from inducible airway GM-CSF over-expressing transgenic mice (DTGM) were compared to non-inducible littermate controls during influenza A virus infection.
Project description:Alveolar macrophages (AMs) are lung resident phagocytes. They derive from fetal liver monocytes, which colonize the lung during embryonic development and give rise to fully mature AMs perinatally. We have identified TGF- signaling as an indispensible regulator during this process. To analyze the impact of TGF- on the entire transcriptome of AMs, we performed RNA-seq on AMs deficient of Tgfbr2 in CD11cCre/+ Tgfbr2fl/fl mice at P3 with Tgfbr2fl/fl littermates as a control.