Tissue engineering of lung organoids with advanced biomaterials for in-vitro disease modelling
File(s)
Author(s)
Uwagboe, Isabel
Type
Thesis
Abstract
The pathophysiological nature of extracellular matrix (ECM) in pulmonary fibrosis is often overlooked. Chronic Obstructive Pulmonary Disease (COPD), hallmarked by loss of alveolar architecture, thickening of the small airways and mucosal hypersecretion is associated with remodelled lung following continuous exposure to noxious particles and chronic inflammation. The degree of matrix stiffness is amplified in Idiopathic Pulmonary Fibrosis (IPF), a disease linked to fibroblast foci in collapsed alveoli. In both, the microenvironment governed by the ECM deviates from the norm, including reduction of elastin (COPD), increased presence of collagen and other ECM proteins (IPF), becoming stiffer. Within this PhD project, a photo-inducible biosynthetic hydrogel (PMET) containing photoinitiator Eosin Y and co-initiator Triethanolamine was generated, recapitulating the range of stiffnesses seen in these diseases with dynamic control following green light exposure. Encapsulated bronchospheres derived from healthy (NHBEs) and COPD (CHBEs) bronchial epithelial cells were used to investigate the influence of fibrotic-like matrix on normal and diseased cellular phenotype and functionality. RT-qPCR analysis showed upregulation of MUC5AC mRNA expression in NHBE bronchospheres as the PMET matrix became stiffer, with greater increase seen with MUC5B. CHBE models also showed enhanced MUC5AC mRNA expression upon stiffening. Increased expression of cell proliferation marker SOX2 was noted in both models. Single cell RT-qPCR analysis, immunocytochemistry and western blotting explored the expression of key mechanosensitive proteins e.g., YAP1 with upregulation rapidly seen following photo-induction. The magnitude and timing of the mechanoresponse was altered in CHBEs with respect to the healthy donors. In this model, I demonstrate markers of respiratory fibrotic disease including goblet cell hyperplasia, mucin overexpression and cell proliferation are stimulated by increased matrix stiffness. These results highlight the important role of Mechanobiology, with further studies needed to examine the role of YAP signalling in this process, elucidating the bidirectional talk between matrix and cell.
Version
Open Access
Date Issued
2022-07-08
Date Awarded
01/02/2023
License URL
Advisor
Adcock, Ian
Dunlop, Iain
Mumby, Sharon
Sponsor
Engineering and Physical Sciences Research Council
Publisher Department
National Heart & Lung Institute
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)