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- Ax, Elisabeth
(författare)
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Epithelial signatures in respiratory disease
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The epithelium of the human airways protects us against harm and helps maintain immune homeostasis. In respiratory diseases such as asthma and COPD, the functions of the epithelium are altered and can cause or contribute to disease progression. Additionally, these diseases are heterogeneous in regard to which inflammatory mechanisms and pathways are activated, thus creating inflammatory endotypes. Due to these differing endotypes, not all patients respond similarly to currently available treatments. Increased understanding of these endotypes will enable a precision medicine approach for respiratory diseases. In this thesis, responses and functions of the airway epithelium in different possible inflammatory endotypes are investigated using a primary cell-based model system. Three types of epithelial signatures are established in response to inflammatory cytokines: gene expression, extracellular vesicle proteome, and miRNA expression. In Paper I, the IL-6 trans-signaling gene signature is used to identify a subtype of asthma patients with increased activation of this pathway in the airway epithelium. These patients demonstrate increased inflammation, epithelial barrier damage, and higher number of asthma exacerbations indicative of poorly controlled disease. This suggests that these patients could benefit from treatment blocking activation of the IL-6 transsignaling pathway. In Paper II, extracellular vesicles released from epithelial cells stimulated with T2 and Th17 cytokines show proteomic differences related to airway disease-relevant processes. This is exemplified through the effect of the vesicles released under Th17 inflammatory conditions in promoting neutrophil migration. These findings enhance the knowledge about the contribution of epithelial extracellular vesicles in airway disease. In Paper III, Th17 cytokines are shown to cause disruption of the airway epithelial barrier and induce the expression of several miRNAs predicted to target barrier-related genes. Preliminary results identify two miRNAs as possible candidates that interact with, and cause decreased levels of, mRNAs encoding proteins involved in formation of the epithelial barrier. This highlights the role of miRNAs as master regulators of genes important to airway epithelial functions. Altogether, these studies show the diverse and fine-tuned responses and functions of the airway epithelium in inflammatory environments similar to what could be present in patients with respiratory disease. The results thus contribute to the understanding of endotype-specific processes taking place locally in the airways. Ultimately, increased knowledge of disease-driving mechanisms will lead to the development of novel treatments and biomarkers that can be used to improve the lives of patients with respiratory disease.
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| 2. |
- Ax, Elisabeth, et al.
(författare)
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T2 and T17 cytokines alter the cargo and function of airway epithelium-derived extracellular vesicles
- 2020
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Ingår i: Respiratory Research. - : Springer Science and Business Media LLC. - 1465-993X. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Asthma is a common and heterogeneous disease that includes subgroups characterized by type 2 (T2) or type 17 (T17) immune responses for which there is a need to identify the underlying mechanisms and biomarkers in order to develop specific therapies. These subgroups can be defined by airway epithelium gene signatures and the airway epithelium has also been implicated to play a significant role in asthma pathology. Extracellular vesicles (EVs) carry functional biomolecules and participate in cell-to-cell communication in both health and disease, properties that are likely to be involved in airway diseases such as asthma. The aim of this study was to identify stimulus-specific proteins and functionality of bronchial epithelium-derived EVs following stimulation with T2 or T17 cytokines. Methods EVs from cytokine-stimulated (T2: IL-4 + IL-13 or T17: IL-17A + TNF alpha) human bronchial epithelial cells cultured at air-liquid interface (HBEC-ALI) were isolated by density cushion centrifugation and size exclusion chromatography and characterized with Western blotting and electron microscopy. Transcriptomic (cells) and proteomic (EVs) profiling was also performed. Results Our data shows that EVs are secreted and can be isolated from the apical side of HBEC-ALI and that cytokine stimulation increases EV release. Genes upregulated in cells stimulated with T2 or T17 cytokines were increased also on protein level in the EVs. Proteins found in T17-derived EVs were suggested to be involved in pathways related to neutrophil movement which was supported by assessing neutrophil chemotaxis ex vivo. Conclusions Together, the results suggest that epithelial EVs are involved in airway inflammation and that the EV proteome may be used for discovery of disease-specific mechanisms and signatures which may enable a precision medicine approach to the treatment of asthma.
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| 3. |
- Calvén, Jenny, et al.
(författare)
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The airway epithelium—a central player in asthma pathogenesis
- 2020
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 21:23, s. 1-29
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Tidskriftsartikel (refereegranskat)abstract
- Asthma is a chronic inflammatory airway disease characterized by variable airflow obstruction in response to a wide range of exogenous stimuli. The airway epithelium is the first line of defense and plays an important role in initiating host defense and controlling immune responses. Indeed, increasing evidence indicates a range of abnormalities in various aspects of epithelial barrier function in asthma. A central part of this impairment is a disruption of the airway epithelial layer, allowing inhaled substances to pass more easily into the submucosa where they may interact with immune cells. Furthermore, many of the identified susceptibility genes for asthma are expressed in the airway epithelium. This review focuses on the biology of the airway epithelium in health and its pathobiology in asthma. We will specifically discuss external triggers such as allergens, viruses and alarmins and the effect of type 2 inflammatory responses on airway epithelial function in asthma. We will also discuss epigenetic mechanisms responding to external stimuli on the level of transcriptional and posttranscriptional regulation of gene expression, as well the airway epithelium as a potential treatment target in asthma. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
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| 4. |
- Jevnikar, Z., et al.
(författare)
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Epithelial IL-6 trans-signaling defines a new asthma phenotype with increased airway inflammation
- 2019
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 143:2, s. 577-590
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Tidskriftsartikel (refereegranskat)abstract
- Background: Although several studies link high levels of IL-6 and soluble IL-6 receptor (sIL-6R) to asthma severity and decreased lung function, the role of IL-6 trans-signaling (IL-6TS) in asthmatic patients is unclear. Objective: We sought to explore the association between epithelial IL-6TS pathway activation and molecular and clinical phenotypes in asthmatic patients. Methods: An IL-6TS gene signature obtained from air-liquid interface cultures of human bronchial epithelial cells stimulated with IL-6 and sIL-6R was used to stratify lung epithelial transcriptomic data (Unbiased Biomarkers in Prediction of Respiratory Disease Outcomes [U-BIOPRED] cohorts) by means of hierarchical clustering. IL-6TS-specific protein markers were used to stratify sputum biomarker data (Wessex cohort). Molecular phenotyping was based on transcriptional profiling of epithelial brushings, pathway analysis, and immunohistochemical analysis of bronchial biopsy specimens. Results: Activation of IL-6TS in air-liquid interface cultures reduced epithelial integrity and induced a specific gene signature enriched in genes associated with airway remodeling. The IL-6TS signature identified a subset of patients with IL-6TS-high asthma with increased epithelial expression of IL-6TS-inducible genes in the absence of systemic inflammation. The IL-6TS-high subset had an overrepresentation of frequent exacerbators, blood eosinophilia, and submucosal infiltration of T cells and macrophages. In bronchial brushings Toll-like receptor pathway genes were upregulated, whereas expression of cell junction genes was reduced. Sputum sIL-6R and IL-6 levels correlated with sputum markers of remodeling and innate immune activation, in particular YKL-40, matrix metalloproteinase 3, macrophage inflammatory protein 1 beta, IL-8, and IL-1 beta. Conclusions: Local lung epithelial IL-6TS activation in the absence of type 2 airway inflammation defines a novel subset of asthmatic patients and might drive airway inflammation and epithelial dysfunction in these patients.
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| 6. |
- Winslow, S., et al.
(författare)
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Multi-omics links IL-6 trans-signalling with neutrophil extracellular trap formation and Haemophilus infection in COPD
- 2021
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 58:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Interleukin (IL)-6 trans-signalling (IL-6TS) is emerging as a pathogenic mechanism in chronic respiratory diseases; however, the drivers of IL-6TS in the airways and the phenotypic characteristic of patients with increased IL-6TS pathway activation remain poorly understood. Objective: Our aim was to identify and characterise COPD patients with increased airway IL-6TS and to elucidate the biological drivers of IL-6TS pathway activation. Methods: We used an IL-6TS-specific sputum biomarker profile (soluble IL-6 receptor (sIL-6R), IL-6, IL1 beta, IL-8, macrophage inflammatory protein-1 beta) to stratify sputum data from patients with COPD (n=74; Biomarkers to Target Antibiotic and Systemic Corticosteroid Therapy in COPD Exacerbation (BEAT-COPD)) by hierarchical clustering. The IL-6TS signature was related to clinical characteristics and sputum microbiome profiles. The induction of neutrophil extracellular trap formation (NETosis) and IL-6TS by Haemophilus influenzae were studied in human neutrophils. Results: Hierarchical clustering revealed an IL-6TS-high subset (n=24) of COPD patients, who shared phenotypic traits with an IL-6TS-high subset previously identified in asthma. The subset was characterised by increased sputum cell counts (p=0.0001), persistent sputum neutrophilia (p=0.0004), reduced quality of life (Chronic Respiratory Questionnaire total score; p=0.008), and increased levels of pro-inflammatory mediators and matrix metalloproteinases in sputum. IL-6TS-high COPD patients showed an increase in Proteobacteria, with Haemophilus as the dominating genus. NETosis induced by H. influenzae was identified as a potential mechanism for increased sIL-6R levels. This was supported by a significant positive correlation between sIL-6R and NETosis markers in bronchoalveolar lavage fluid from COPD patients. Conclusion: IL-6TS pathway activation due to chronic colonisation with Haemophilus may be an important disease driver in a subset of COPD patients.
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