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Supervisor: Dr Rob Hynds, David Pearce, Rachel Chambers
Project Description:
Background
Airway stenosis (narrowing) is a major clinical problem, occurring as a complication in patients who have undergone endotracheal intubation, tracheostomy, laryngotracheal reconstruction surgery and radiation therapy. In children, stenosis can be congenital or follow tracheo-oesophageal fistula surgery. A severe, often fatal, form of airway stenosis occurs in epidermolysis bullosa (EB), a rare but devastating genetic disorder in which patients suffer from extremely fragile skin that painfully blisters and scars with minimal trauma. Junctional EB (JEB) is caused by variants in genes that encode hemidesmosome components (1). Hemidesmosomes are junctional complexes that bridge intracellular keratin intermediate filament networks and subepithelial collagen fibrils via integrin receptors. JEB mutations disrupt cell adhesion, causing epithelial fragility, inflammation and fibrosis/scarring. The heterotrimeric protein complex laminin-332 – encoded by the genes LAMA3, LAMB3, and LAMC2 – acts as a molecular anchor between integrins and collagen fibrils in the extracellular matrix (ECM). In the airway, laminin-332 is produced by basal epithelial cells, a multipotent stem cell population.
At Great Ormond Street Hospital (GOSH), we have identified a cohort of ‘airway EB’ patients who suffer significant morbidity and mortality due to laryngeal and tracheal disease. Patients have fragile airway epithelia sensitive to damage by mild stimuli (e.g. coughing), require frequent intervention, and often require tracheostomy, which itself can exacerbate airway injury. EB airway disease often results from loss of laminin-332 caused by genetic variants in LAMA3. Thus, EB represents a model form of airway stenosis in which chronic epithelial injury leads to progressive inflammation, granulation tissue formation and fibrosis. Therapeutic options for these patients are limited and aim for palliative symptom control. This PhD project aims to address this by testing the hypothesis that the re-purposing of the FDA/EMA-approved anti-fibrotic drugs pirfenidone and nintedanib, which slow the progression of lung fibrosis, will slow the progression of EB-associated airway stenosis.
Aims/Objectives
Aim 1: Investigate the effects of pirfenidone and nintedanib on fibrotic read-outs in human and mouse airway organoid co-cultures.
Aim 2: Investigate anti-fibrotic therapies in a mouse model of airway EB.
Aim 3: Determine mechanisms of fibroblast activation and collagen deposition to reveal novel therapeutic targets in airway EB.
Methods
This project builds on extensive preliminary data that has established cutting-edge in vitro and in vivo platforms to model airway disease in epidermolysis bullosa. The candidate will learn advanced cell culture, molecular biology and imaging techniques, as well as receive training in mouse modelling of disease and bioinformatic analysis of sequencing data.
Timeline
Initial cell culture studies will be performed to determine the effect of pirfenidone and nintedanib on airway epithelial cell and fibroblast transcriptional profiles, including in organoid co-culture. The effects of other potentially anti-fibrotic therapies in development for lung fibrosis will also be explored. During this initial 12 months, the candidate will be trained in in vivo methods and obtain a Home Office license. During the second year, they will initiate in vivo experimentation guided by their in vitro findings.
References
1) Bardhan et al. Epidermolysis Bullosa. Nat. Rev. Dis. Primers (2020; https://doi.org/10.1038/s41572-020-0210-0)
2) Lau et al. Lentiviral expression of wild-type LAMA3A restores cell adhesion in airway basal cells from children with epidermolysis bullosa. Molecular Therapy (2024; https://doi.org/10.1016/j.ymthe.2024.02.032)
Contact Information:
Rob Hynds
