In vitro and in vivo evaluation of the effect of Aspergillus fumigatus on epithelial cells.

Pitsilioni, Olga

Abstract

Aspergillus fumigatus is a saprophytic fungus and one of the most prevalent airborne pathogens. Asthma is severe and associated with increased mortality in those patients that have fungal sensitisation. Mechanisms of airway wall remodelling and the potential involvement of fibrin deposition, as well as the miRNA biomarkers of airway- Aspergillus fumigatus interactions are yet to be identified. The aim of this study was to evaluate the extent of lung pathology, including fibrin deposition in murine models of Aspergillus fumigatus sensitisation. Furthermore, this work set out to identify miRNA biomarkers of Aspergillus fumigatus induced airway damage and to investigate the effects of co-exposure to fibrin and Aspergillus fumigatus in vitro. It was hypothesised that Aspergillus fumigatus exposure would be associated with fibrin deposits in the lung. Furthermore, it was hypothesised that fibrin and Aspergillus fumigatus would have a pathological impact on epithelial cells in vitro. Lung tissue sections from control mice and models of Aspergillus fumigatus sensitisation including those exposed to culture filtrate, culture filtrates plus an Endothelin-1 antagonist and a commercially sourced extract were stained by H&E, Masson’s Trichrome, Periodic Acid Schiff and Carstair’s staining for fibrin and platelets. The impact of fungal sensitisation and the therapeutic potential of Endothelin-1 antagonism was assessed. In vitro, proinflammatory cytokine induction and airway epithelial morphological changes in response to two different strains of Aspergillus fumigatus and fibrin were also investigated. Exposure to Aspergillus fumigatus caused a significant increase in airway and blood vessel inflammation and remodelling, with no therapeutic benefits of Endothelin-1 antagonism observed. Induction of cytokines, IL-6, IL-8 and Endothelin-1, in response to Aspergillus fumigatus exposure was significant in two different cell lines (A549 and 16HBE), and in the co-exposure model of fibrin and Aspergillus fumigatus. Finally, Aspergillus fumigatus caused a downregulated expression of miRNAs relevant to lung fibrosis including: miR-9-5p, miR-223-5p, miR-155-5p, miR-21-5p miR-320a-3p, miR-130b-3p, miR-223-3p and miR-34a-5p. This work confirms that Aspergillus fumigatus and fibrin cause pro-inflammatory cytokine induction in vitro and suggest a possible role of fibrin in airway pathology in vivo. . We also observed downregulation of miRNA in response to Aspergillus fumigatus exposure ,findings that can give insight for future directions of the research into novel biomarkers in Aspergillosis .

Citation

Pitsilioni, O. (2024). In vitro and in vivo evaluation of the effect of Aspergillus fumigatus on epithelial cells. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 31, 2024
• Publicly Available Date: Nov 25, 2024
• Award Date: Oct 24, 2024