262 results found
Pyle CJ, Labeur-Iurman L, Groves HT, et al., 2021, Enhanced IL-2 in early life limits the development of TFH and protective antiviral immunity, Journal of Experimental Medicine, Vol: 218, ISSN: 0022-1007
T follicular helper cell (TFH)-dependent antibody responses are critical for long-term immunity. Antibody responses are diminished in early life, limiting long-term protective immunity and allowing prolonged or recurrent infection, which may be important for viral lung infections that are highly prevalent in infancy. In a murine model using respiratory syncytial virus (RSV), we show that TFH and the high-affinity antibody production they promote are vital for preventing disease on RSV reinfection. Following a secondary RSV infection, TFH-deficient mice had significantly exacerbated disease characterized by delayed viral clearance, increased weight loss, and immunopathology. TFH generation in early life was compromised by heightened IL-2 and STAT5 signaling in differentiating naive T cells. Neutralization of IL-2 during early-life RSV infection resulted in a TFH-dependent increase in antibody-mediated immunity and was sufficient to limit disease severity upon reinfection. These data demonstrate the importance of TFH in protection against recurrent RSV infection and highlight a mechanism by which this is suppressed in early life.
McErlean P, Bell CG, Hewitt RJ, et al., 2021, DNA methylome alterations are associated with airway macrophage differentiation and phenotype during lung fibrosis., American Journal of Respiratory and Critical Care Medicine, Vol: 204, Pages: 954-966, ISSN: 1073-449X
Rationale: Airway macrophages (AMs) are key regulators of the lung environment and are implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF), a fatal respiratory disease with no cure. However, knowledge about the epigenetics of AMs in IPF is limited. Objectives: To assess the role of epigenetic regulation of AMs during lung fibrosis. Methods: We undertook DNA methylation (DNAm) profiling by using Illumina EPIC (850k) arrays in sorted AMs from healthy donors (n = 14) and donors with IPF (n = 30). Cell-type deconvolution was performed by using reference myeloid-cell DNA methylomes. Measurements and Main Results: Our analysis revealed that epigenetic heterogeneity was a key characteristic of IPF AMs. DNAm "clock" analysis indicated that epigenetic alterations in IPF AMs were not associated with accelerated aging. In differential DNAm analysis, we identified numerous differentially methylated positions (n = 11) and differentially methylated regions (n = 49) between healthy and IPF AMs, respectively. Differentially methylated positions and differentially methylated regions encompassed genes involved in lipid (LPCAT1 [lysophosphatidylcholine acyltransferase 1]) and glucose (PFKFB3 [6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3]) metabolism, and importantly, the DNAm status was associated with disease severity in IPF. Conclusions: Collectively, our data identify that changes in the epigenome are associated with the development and function of AMs in the IPF lung.
Saglani S, Robinson P, Fontanella S, et al., 2021, Recurrent severe preschool wheeze: From pre-specified diagnostic labels to underlying endotypes, American Journal of Respiratory and Critical Care Medicine, Vol: 204, Pages: 523-535, ISSN: 1073-449X
Rationale: Preschool wheezing is heterogeneous, but the underlying mechanisms are poorly understood. Objectives: To investigate lower airway inflammation and infection in preschool children with different clinical diagnoses undergoing elective bronchoscopy/bronchoalveolar lavage-BAL. Methods: We recruited 136 children aged 1-5 years (105 recurrent severe wheeze-RSW; 31 non-wheeze respiratory disorders-NWRD). RSW were assigned as episodic viral-EVW or multiple trigger wheeze-MTW. We compared lower airway inflammation/infection in different clinical diagnoses and undertook data-driven analyses to determine clusters of pathophysiological features, and investigated their relationships with pre-specified diagnostic labels. Measurements and Main Results: Blood eosinophils and allergic sensitization were significantly higher in RSW than NWRD. Blood neutrophils, BAL eosinophils and neutrophils, and positive bacterial culture and virus detection rates were similar between groups. However, pathogen distribution differed significantly, with higher detection of rhinovirus in RSW and Moraxella in sensitized RSW. EVW and MTW did not differ in blood/BAL inflammation, or bacterial/virus detection. Partition Around Medoids algorithm revealed 4 clusters of pathophysiological features: (1) Atopic (17.9%); (2) Non-atopic, low infection rate, high inhaled corticosteroids-ICS (31.3%); (3) Non-atopic, high infection rate (23.1%); and (4) Non-atopic, low infection rate, no ICS (27.6%). Cluster allocation differed significantly between RSW and NWRD (RSW evenly distributed across clusters, 60% of NWRD assigned to cluster 4, p<0.001). There was no difference in cluster membership between EVW and MTW. Cluster 1 was dominated by Moraxella detection (p=0.04) and Cluster 3 by Haemophilus/Staphylococcus/ Streptococcus (p=0.02). Conclusions: We identified four clusters of severe preschool wheeze distinguished using sensitization, peripheral eosinophilia, lower airway neutrophilia and bacteriolog
Branchett WJ, Cook J, Oliver RA, et al., 2021, Airway macrophage-intrinsic TGF-β1 regulates pulmonary immunity during early life allergen exposure, Journal of Allergy and Clinical Immunology, Vol: 147, Pages: 1892-1906, ISSN: 0091-6749
BackgroundEarly life represents a major risk window for asthma development. However, the mechanisms controlling the threshold for establishment of allergic airway inflammation in early life are incompletely understood. Airway macrophages (AMs) regulate pulmonary allergic responses and undergo TGF-β–dependent postnatal development, but the role of AM maturation factors such as TGF-β in controlling the threshold for pathogenic immune responses to inhaled allergens remains unclear.ObjectiveOur aim was to test the hypothesis that AM-derived TGF-β1 regulates pathogenic immunity to inhaled allergen in early life.MethodsConditional knockout (Tgfb1ΔCD11c) mice, with TGF-β1 deficiency in AMs and other CD11c+ cells, were analyzed throughout early life and following neonatal house dust mite (HDM) inhalation. The roles of specific chemokine receptors were determined by using in vivo blocking antibodies.ResultsAM-intrinsic TGF-β1 was redundant for initial population of the neonatal lung with AMs, but AMs from Tgfb1ΔCD11c mice failed to adopt a mature homeostatic AM phenotype in the first weeks of life. Evidence of constitutive TGF-β1 signaling was also observed in pediatric human AMs. TGF-β1–deficient AMs expressed enhanced levels of monocyte-attractant chemokines, and accordingly, Tgfb1ΔCD11c mice exposed to HDM throughout early life accumulated CCR2-dependent inflammatory CD11c+ mononuclear phagocytes into the airway niche that expressed the proallergic chemokine CCL8. Tgfb1ΔCD11c mice displayed augmented TH2, group 2 innate lymphoid cell, and airway remodeling responses to HDM, which were ameliorated by blockade of the CCL8 receptor CCR8.ConclusionOur results highlight a causal relationship between AM maturity, chemokines, and pathogenic immunity to environmental stimuli in early life and identify TGF-β1 as a key regulator of this.
Harker JA, Lloyd CM, 2021, Overlapping and distinct features of viral and allergen immunity in the human lung, IMMUNITY, Vol: 54, Pages: 617-631, ISSN: 1074-7613
Invernizzi R, Wu BG, Barnett J, et al., 2021, The respiratory microbiome in chronic hypersensitivity pneumonitis is distinct from that of idiopathic pulmonary fibrosis, American Journal of Respiratory and Critical Care Medicine, Vol: 203, Pages: 339-347, ISSN: 1073-449X
RATIONALE: Chronic hypersensitivity pneumonitis (CHP) is a condition that arises following repeated exposure and sensitisation to inhaled antigens. The lung microbiome is increasingly implicated in respiratory disease but to date, no study has investigated the composition of microbial communities in the lower airways in CHP. OBJECTIVE: To characterise and compare the airway microbiome in subjects with CHP, idiopathic pulmonary fibrosis (IPF) and controls. METHODS: We prospectively recruited individuals diagnosed with CHP (n=110), IPF (n=45) and controls (n=28). Subjects underwent bronchoalveolar lavage and bacterial DNA was isolated, quantified by qPCR and the 16S rRNA gene was sequenced to characterise the bacterial communities in the lower airways. MAIN MEASUREMENTS AND RESULTS: Distinct differences in the microbial profiles were evident in the lower airways of subjects with CHP and IPF. At the phylum level, the prevailing microbiota of both IPF and CHP subjects included Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria. However, in IPF, Firmicutes dominated while the percentage of reads assigned to Proteobacteria in the same group was significantly lower compared to CHP subjects. At the genus level, Staphylococcus was increased in CHP and Actinomyces and Veillonella in IPF. The lower airway bacterial burden in CHP subjects was higher than controls but lower than those with IPF. In contrast to IPF, there was no association between bacterial burden and survival in CHP. CONCLUSIONS: The microbial profile of the lower airways in subjects with CHP is distinct from that of IPF and, notably, bacterial burden in individuals with CHP fails to predict survival.
Invernizzi R, Giallourou N, Swann JR, et al., 2021, THE RESPIRATORY MICROBIOME AND METABOLOME IN IDIOPATHIC PULMONARY FIBROSIS, Publisher: BMJ PUBLISHING GROUP, Pages: A2-A3, ISSN: 0040-6376
Albers GJ, Iwasaki J, McErlean P, et al., 2021, IRF5 regulates airway macrophage metabolic responses, CLINICAL AND EXPERIMENTAL IMMUNOLOGY, Vol: 204, Pages: 134-143, ISSN: 0009-9104
Hewitt RJ, Lloyd CM, 2021, Regulation of immune responses by the airway epithelial cell landscape, NATURE REVIEWS IMMUNOLOGY, Vol: 21, Pages: 347-362, ISSN: 1474-1733
Branchett WJ, Walker SA, Lloyd CM, 2021, Experimental Mouse Models of Asthma and Analysis of CD4 T Cells., Methods Mol Biol, Vol: 2285, Pages: 329-348
Asthma is a highly prevalent lung disease, characterized by airway dysfunction and chronic inflammation. Asthma occurs in both children and adults, but frequently originates in early life. Heterogeneous asthma phenotypes exist, but Th2 cells are key players in a large proportion of cases, while other CD4+ T cell subsets are also implicated in driving and limiting pathology. In this chapter, we describe methods for establishing allergic airway disease to model asthma in adult and neonatal mice, along with protocols for measuring key disease parameters and quantifying and phenotyping CD4+ T cell subtypes.
Durrington HJ, Krakowiak K, Meijer P, et al., 2020, Circadian asthma airway responses are gated by REV-ERB alpha, EUROPEAN RESPIRATORY JOURNAL, Vol: 56, ISSN: 0903-1936
Porsbjerg CM, Sverrild A, Lloyd CM, et al., 2020, Anti-alarmins in asthma: targeting the airway epithelium with next-generation biologics, EUROPEAN RESPIRATORY JOURNAL, Vol: 56, ISSN: 0903-1936
Ogger PP, Albers GJ, Hewitt RJ, et al., 2020, Itaconate controls the severity of pulmonary fibrosis, Science Immunology, Vol: 5, Pages: 1-13, ISSN: 2470-9468
Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease in which airway macrophages (AMs) play a key role. Itaconate has emerged as a mediator of macrophage function, but its role during fibrosis is unknown. Here, we reveal that itaconate is an endogenous antifibrotic factor in the lung. Itaconate levels are reduced in bronchoalveolar lavage, and itaconate-synthesizing cis-aconitate decarboxylase expression (ACOD1) is reduced in AMs from patients with IPF compared with controls. In the murine bleomycin model of pulmonary fibrosis, Acod1-/- mice develop persistent fibrosis, unlike wild-type (WT) littermates. Profibrotic gene expression is increased in Acod1-/- tissue-resident AMs compared with WT, and adoptive transfer of WT monocyte-recruited AMs rescued mice from disease phenotype. Culture of lung fibroblasts with itaconate decreased proliferation and wound healing capacity, and inhaled itaconate was protective in mice in vivo. Collectively, these data identify itaconate as critical for controlling the severity of lung fibrosis, and targeting this pathway may be a viable therapeutic strategy.
Ubags NDJ, Alcazar MAA, Kallapur SG, et al., 2020, Early origins of lung disease: towards an interdisciplinary approach, EUROPEAN RESPIRATORY REVIEW, Vol: 29, ISSN: 0905-9180
Albers GJ, Iwasaki J, Mcerlean P, et al., 2020, IRF5 regulates airway macrophage metabolic responses to viral challenge, European-Academy-of-Allergology-and-Clinical-Immunology Digital Congress (EAACI), Publisher: WILEY, Pages: 42-43, ISSN: 0105-4538
Andersson CK, Iwasaki J, Cook J, et al., 2020, Impaired airway epithelial cell wound-healing capacity is associated with airway remodelling following RSV infection in severe preschool wheeze, ALLERGY, Vol: 75, Pages: 3195-3207, ISSN: 0105-4538
Invernizzi R, Lloyd CM, Molyneaux PL, 2020, Respiratory microbiome and epithelial interactions shape immunity in the lungs, Immunology, Vol: 160, Pages: 171-182, ISSN: 0019-2805
The airway epithelium represents a physical barrier to the external environment acting as the first line of defence against potentially harmful environmental stimuli including microbes and allergens. However, lung epithelial cells are increasingly recognised as active effectors of microbial defence, contributing to both innate and adaptive immune function in the lower respiratory tract. These cells express an ample repertoire of pattern-recognition receptors with specificity for conserved microbial and host motifs. Modern molecular techniques have uncovered the complexity of the lower respiratory tract microbiome. The interaction between the microbiota and the airway epithelium is key to understanding how stable immune homeostasis is maintained. Loss of epithelial integrity following exposure to infection can result in the onset of inflammation in susceptible individuals and may culminate in lung disease. Here we discuss the current knowledge regarding the molecular and cellular mechanisms by which the pulmonary epithelium interacts with the lung microbiome in shaping immunity in the lung. Specifically, we focus on the interactions between the lung microbiome and the cells of the conducting airways in modulating immune cell regulation and how defects in barrier structure and function may culminate in lung disease. Understanding these interactions is fundamental in the search for more effective therapies for respiratory diseases.
Foster W, Grime C, Tan H-L, et al., 2020, Enhanced frequency and function of follicular T cells in the tonsils of house dust mite sensitized children, Allergy, Vol: 75, Pages: 1240-1243, ISSN: 0105-4538
Invernizzi R, Barnett J, Rawal B, et al., 2020, Bacterial burden in the lower airways predicts disease progression in idiopathic pulmonary fibrosis and is independent of radiological disease extent, European Respiratory Journal, Vol: 55, Pages: 1-9, ISSN: 0903-1936
Increasing bacterial burden in the lower airways of patients with idiopathic pulmonary fibrosis confers an increased risk of disease progression and mortality. However, it remains unclear whether this increased bacterial burden directly influences progression of fibrosis or simply reflects the magnitude of the underlying disease extent or severity.We prospectively recruited 193 patients who underwent bronchoscopy and received a multidisciplinary diagnosis of idiopathic pulmonary fibrosis. Quantification of the total bacterial burden in bronchoalveolar lavage fluid was performed by 16S rRNA gene qPCR. Imaging was independently evaluated by two readers assigning quantitative scores for extent, severity and topography of radiographic changes and relationship of these features with bacterial burden was assessed.Increased bacterial burden significantly associated with disease progression (hazard ratio 2.1; 95% confidence interval 1.287–3.474; p=0.0028). Multivariate stepwise regression demonstrated no relationship between bacterial burden and radiological features or extent of disease. When specifically considering patients with definite or probable usual interstitial pneumonia there was no difference in bacterial burden between these two groups. Despite a postulated association between pleuroparenchymal fibroelastosis and clinical infection, there was no relationship between either the presence or extent of pleuroparenchymal fibroelastosis and bacterial burden.We demonstrate that bacterial burden in the lower airways is not simply secondary to the extent of the underlying architectural destruction of the lung parenchyma seen in idiopathic pulmonary fibrosis. The independent nature of this association supports a relationship with the underlying pathogenic mechanisms and highlights the urgent need for functional studies.
Broadbent L, Manzoor S, Zarcone MC, et al., 2020, Comparative primary paediatric nasal epithelial cell culture differentiation and RSV-induced cytopathogenesis following culture in two commercial media, PLoS One, Vol: 15, Pages: 1-12, ISSN: 1932-6203
The culture of differentiated human airway epithelial cells allows the study of pathogen-host interactions and innate immune responses in a physiologically relevant in vitro model. As the use of primary cell culture has gained popularity the availability of the reagents needed to generate these cultures has increased. In this study we assessed two different media, Promocell and PneumaCult, during the differentiation and maintenance of well-differentiated primary nasal epithelial cell cultures (WD-PNECs). We compared and contrasted the consequences of these media on WD-PNEC morphological and physiological characteristics and their responses to respiratory syncytial virus (RSV) infection. We found that cultures generated using PneumaCult resulted in greater total numbers of smaller, tightly packed, pseudostratified cells. However, cultures from both media resulted in similar proportions of ciliated and goblet cells. There were no differences in RSV growth kinetics, although more ciliated cells were infected in the PneumaCult cultures. There was also significantly more IL-29/IFNλ1 secreted from PneumaCult compared to Promocell cultures following infection. In conclusion, the type of medium used for the differentiation of primary human airway epithelial cells may impact experimental results.
Branchett W, Stoelting H, Oliver R, et al., 2020, A T cell-myeloid IL-10 axis regulates pathogenic IFN-γ-dependent immunity in a mouse model of type 2-low asthma, Journal of Allergy and Clinical Immunology, Vol: 145, Pages: 666-678.e9, ISSN: 0091-6749
BackgroundAlthough originally defined as a type 2 (T2) immune-mediated condition, non-T2 cytokines, such as IFN-γ and IL-17A, have been implicated in asthma pathogenesis, particularly severe disease. IL-10 regulates T helper (Th) cell phenotypes and can dampen T2 immunity to allergens, but its functions in controlling non-T2 cytokine responses in asthma are unclear. Objective: Determine how IL-10 regulates the balance of Th cell responses to inhaled allergen.MethodsAllergic airway disease (AAD) was induced in wild-type, IL-10 reporter and conditional IL-10 or IL-10 receptor α (IL-10Rα) knockout mice, by repeated intranasal administration of house dust mite (HDM). IL-10 and IFN-γ signalling were disrupted using blocking antibodies.ResultsRepeated HDM inhalation induced a mixed IL-13/IL-17A response and accumulation of IL-10-producing FoxP3- effector CD4+ T cells in the lungs. Ablation of T cell-derived IL-10 increased the IFN-γ and IL-17A response to HDM, reducing IL-13 levels and airway eosinophilia without affecting IgE or airway hyperresponsiveness. The increased IFN-γ response could be recapitulated by IL-10Rα deletion in CD11c+ myeloid cells or local IL-10Rα blockade. Disruption of the T cell-myeloid IL-10 axis resulted in elevated pulmonary monocyte-derived dendritic cell numbers and increased IFN-γ-dependent expression of CXCR3 ligands by airway macrophages, suggestive of a feedforward loop of Th1 cell recruitment. Augmented IFN-γ responses in the HDM AAD model were accompanied by increased disruption of airway epithelium, which was reversed by therapeutic blockade of IFN-γ.ConclusionsIL-10 from effector T cells signals to CD11c+ myeloid cells to suppress an atypical and pathogenic IFN-γ response to inhaled HDM.
Entwistle L, Gregory L, Oliver R, et al., 2020, Pulmonary group 2 innate lymphoid cell phenotype is context specific: Determining the effect of strain, location and stimuli, Frontiers in Immunology, Vol: 10, ISSN: 1664-3224
Group 2 innate lymphoid cells (ILC2s) are enriched at mucosal sites, including the lung, and play a central role in type 2 immunity and maintaining tissue homeostasis. As a result, since their discovery in 2010, research into ILC2s has increased markedly. Numerous strategies have been used to define ILC2s by flow cytometry, often utilizing different combinations of surface markers despite their expression being variable and context-dependent. In this study, we sought to generate a comprehensive characterization of pulmonary ILC2s, identifying stable and context specific markers from different pulmonary compartments following different airway exposures in different strains of mice. Our analysis revealed that pulmonary ILC2 surface marker phenotype is heterogeneous and is influenced by mouse strain, pulmonary location, in vivo treatment/exposure and ex vivo stimulation. Therefore, we propose that a lineage negative cell expressing CD45 and Gata3 defines an ILC2, and subsequent surface marker expression should be used to describe their phenotype in context-specific scenarios.
Byrne A, powell J, O'Sullivan B, et al., 2020, Dynamics of human monocytes and airway macrophages during healthy aging and post-transplant, Journal of Experimental Medicine, Vol: 217, Pages: 1-9, ISSN: 0022-1007
The ontogeny of airway macrophages (AMs) in human lung and their contribution to disease are poorly mapped out. In mice, aging is associated with an increasing proportion of peripherally, as opposed to perinatally derived AMs. We sought to understand AM ontogeny in human lung during healthy aging and after transplant. We characterized monocyte/macrophage populations from the peripheral blood and airways of healthy volunteers across infancy/childhood (2–12 yr), maturity (20–50 yr), and older adulthood (>50 yr). Single-cell RNA sequencing (scRNA-seq) was performed on airway inflammatory cells isolated from sex-mismatched lung transplant recipients. During healthy aging, the proportions of blood and bronchoalveolar lavage (BAL) classical monocytes peak in adulthood and decline in older adults. scRNA-seq of BAL cells from lung transplant recipients indicates that after transplant, the majority of AMs are recipient derived. These data show that during aging, the peripheral monocyte phenotype is consistent with that found in the airways and, furthermore, that the majority of human AMs after transplant are derived from circulating monocytes.
Abeler-Dorner L, Laing AG, Lorenc A, et al., 2020, High-throughput phenotyping reveals expansive genetic and structural underpinnings of immune variation, Nature Immunology, Vol: 21, Pages: 86-100, ISSN: 1529-2908
By developing a high-density murine immunophenotyping platform compatible with high-throughput genetic screening, we have established profound contributions of genetics and structure to immune variation (http://www.immunophenotype.org). Specifically, high-throughput phenotyping of 530 unique mouse gene knockouts identified 140 monogenic ‘hits’, of which most had no previous immunologic association. Furthermore, hits were collectively enriched in genes for which humans show poor tolerance to loss of function. The immunophenotyping platform also exposed dense correlation networks linking immune parameters with each other and with specific physiologic traits. Such linkages limit freedom of movement for individual immune parameters, thereby imposing genetically regulated ‘immunologic structures’, the integrity of which was associated with immunocompetence. Hence, we provide an expanded genetic resource and structural perspective for understanding and monitoring immune variation in health and disease.
Hewitt RJ, Graham C, Perez-Lloret J, et al., 2020, A Transcriptomic Profile of the Proximal Airway Epithelial-Immune Niche in Idiopathic Pulmonary Fibrosis, International Conference of the American-Thoracic-Society, Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Lloyd CM, Branchett WJ, O'Garra A, 2020, Transcriptomic analysis reveals diverse gene expression changes in airway macrophages during experimental allergic airway disease, Wellcome Open Research, Vol: 5
Background: 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 signals in 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). In this study, we aimed to better understand these potentially contrasting AM functions using transcriptomic analysis. Methods: Bulk RNA sequencing was performed on AMs flow cytometry sorted from C57BL/6 mice during experimental AAD driven by repeated house dust mite inhalation (AMs HDM), compared to control AMs from non-allergic mice. Differentially expressed genes were further analysed by hierarchical clustering and biological pathway analysis. Results: AMs HDM showed increased expression of genes associated with antigen presentation, inflammatory cell recruitment and tissue repair, including several chemokine and matrix metalloproteinase genes. This was accompanied by increased expression of mitochondrial electron transport chain subunit genes and the retinoic acid biosynthetic enzyme gene Raldh2. Conversely, AMs HDM 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 AMs HDM was consistent with upstream effects of the cytokines IL-4 and IFN-γ, both of which were present at increased concentrations in lung tissue after HDM treatment. Conclusions: These data highlight diverse gene expression changes in the total AM population in a clinically relevant mouse model of AAD, collectively suggestive of contributions to inflammation and tissue repair/remodelling, but with decreases in certain steady state cellular and immunological functions.
Turnbull A, Pyle C, Patel D, et al., 2020, Abnormal pro-gly-pro pathway and airway neutrophilia in pediatric cystic fibrosis, Journal of Cystic Fibrosis, Vol: 19, Pages: 40-48, ISSN: 1569-1993
BackgroundProline–glycine–proline (PGP) is a bioactive fragment of collagen generated by the action of matrix metalloproteinase-9 (MMP-9) and prolylendopeptidase (PE), and capable of eliciting neutrophil chemotaxis and epithelial remodelling. PGP is normally then degraded by leukotriene A4 hydrolase (LTA4H) to limit inflammation and remodelling. This study hypothesized that early and persistent airway neutrophilia in Cystic Fibrosis (CF) may relate to abnormalities in the PGP pathway and sought to understand underlying mechanisms.MethodsBroncho-alveolar lavage (BAL) fluid was obtained from 38 CF (9 newborns and 29 older children) and 24 non-CF children. BAL cell differentials and levels of PGP, MMP-9, PE and LTA4H were assessed.ResultsWhilst PGP was present in all but one of the older CF children tested, it was absent in non-CF controls and the vast majority of CF newborns. BAL levels of MMP-9 and PE were elevated in older children with CF relative to CF newborns and non-CF controls, correlating with airway neutrophilia and supportive of PGP generation. Furthermore, despite extracellular LTA4H commonly being greatly elevated concomitantly with inflammation to promote PGP degradation, this was not the case in CF children, potentially owing to degradation by neutrophil elastase.ConclusionsA striking imbalance between PGP-generating and -degrading enzymes enables PGP accumulation in CF children from early life and potentially supports airway neutrophilia.
Entwistle LJ, Puttur F, Gregory LG, et al., 2020, Group 2 ILC Functional Assays in Allergic Airway Inflammation., Methods Mol Biol, Vol: 2121, Pages: 99-114
ILC2s are a rare innate cell population capable of rapidly producing type 2 cytokines prior to the recruitment and expansion of adaptive type 2 T helper cells. As a result, they are implicated in the pathogenesis of many type-2 immune-mediated diseases, including allergic airway inflammation. Here we describe methods for interrogating and analyzing ILC2 biology in the context of allergic airway inflammation, such as flow cytometric analysis of mouse and human ILC2s as well as live imaging of pulmonary ILC2s.
Branchett WJ, O'Garra A, Lloyd CM, 2020, Transcriptomic analysis reveals diverse gene expression changes in airway macrophages during experimental allergic airway disease., Wellcome Open Res, Vol: 5, ISSN: 2398-502X
Background: 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 signals in 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). In this study, we aimed to better understand these potentially contrasting AM functions using transcriptomic analysis. Methods: Bulk RNA sequencing was performed on AMs (CD11c + Siglec F + CD64 + CD45 + SSC hi) flow cytometry sorted from C57BL/6 mice during experimental AAD driven by repeated house dust mite inhalation (AMs HDM), compared to control AMs from non-allergic mice. Differentially expressed genes were further analysed by hierarchical clustering and biological pathway analysis. Results: AMs HDM showed increased expression of genes associated with antigen presentation, inflammatory cell recruitment and tissue repair, including several chemokine and matrix metalloproteinase genes. This was accompanied by increased expression of mitochondrial electron transport chain subunit genes and the retinoic acid biosynthetic enzyme gene Raldh2. Conversely, AMs HDM 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 AMs HDM was consistent with upstream effects of the cytokines IL-4 and IFN-γ, both of which were present at increased concentrations in lung tissue after HDM treatment. Conclusions: These data highlight diverse gene expression changes in the total AM population in a clinically relevant mouse model of AAD, collectively suggestive of contributions to inflammation and tissue repair/remodelling, but with decreases in certain steady state cellular and immunological functions.
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