Item type:Thesis, Open Access

Vergleichende Charakterisierung extrazellulärer Vesikel aus primären humanen Bronchialepithelzellen asthmatischer und gesunder Individuen

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Philipps-Universität Marburg

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Abstract

Bronchial asthma is a widespread chronic inflammatory airway disease that affects more than 300 million people worldwide. The human bronchial epithelium consists of polarized cells with an apical and a basolateral region and plays an important role in the pathogenesis of the disease. Like other cells, bronchial epithelial cells also secrete extracellular vesicles (EVs). EVs are small particles that appear to contribute to intercellular communication. Despite the growing interest in recent years, little is known about the role of EVs in chronic inflammatory processes. Therefore, the aim of the present work was to investigate the structure of EVs from human bronchial epithelial cells and the influence of the polar structure of these cells on the secreted EVs. For this purpose, bronchial epithelial cells extracted by bronchial brushings from asthmatic and healthy individuals were cultured using an air-liquid interface (ALI) system, which enables the cells to differentiate and secrete EVs in an apical and basolateral direction. Samples were taken by removing the culture medium and washing the cell layer. The presence of EVs was confirmed by electron microscopy after purification of the samples with ultrafiltration and size exclusion chromatography. The number and size of EVs as well as surface markers were analyzed by nanoflow cytometry, bead-based flow cytometry and mass spectrometry. We found that bronchial epithelial cells indeed secrete small EVs to both compartments with an increasing focus towards die apical compartment during the time of cellular differentiation. Bead-based flow cytometry as well as proteomic analysis show clearly distinct patterns between the vesicular proteome of both compartments, using principal component analysis (PCA) and hierarchical clustering analysis (HCA). Adjustment with known pathways as well as GO-terms show that these proteins are associated with clearly distinct pathways, separately. While the proteome of apically secreted EVs is associated with transport processes and processes of cytoskeleton and cell adhesion, basolaterally secreted EVs rather seem to be involved in metabolic processes. Due to the small sample size, the complex methods that were used and the complexity of asthmatic airway conditions we have not been able to detect differences between healthy and asthmatic individuals. The results aim towards a distinct role of EVs of both compartments in the intercellular communication of the bronchial epithelium. To investigate this role further, more studies with larger sample sizes and especially functional analyses of accurate isolated EVs of the bronchial epithelium are necessary.

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Hintz, Lukas: Vergleichende Charakterisierung extrazellulärer Vesikel aus primären humanen Bronchialepithelzellen asthmatischer und gesunder Individuen. : Philipps-Universität Marburg 2025-05-15. DOI: https://doi.org/10.17192/z2025.0204.