bREATH-EASy: UNDERSTANDING THE ROLE OF INFECTION & EXTRACELLULAR MATRIX IN IDIOPATHIC PULMONARY FIBROSIS USING STEM CELL DERIVED ALVEOLAR CELLS

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In the UK 1 in 4 people die from respiratory disease. Poor access to lung samples, an inability to culture lung cells and a lack of animal models that reproduce human lung disease has left us with an inadequate understanding of how to diagnose and treat lung disease. These issues are exemplified by idiopathic pulmonary fibrosis (IPF), a disease where rapid scarring reduces lung function leading to death within an average of 3 years. The cause of IPF is unknown and prognosis is difficult to predict. A greater knowledge of lung disease including IPF is needed so diagnosis, prognosis and treatment can be improved.Human pluripotent stem cells are providing new ways to model and understand disease. Until recently however, models for lung diseases were not available. Our recently-published work has addressed this need and we can now produce large numbers of lung alveoli cells, one of the cell types affected by IPF. We can now make 3D lung organoids allowing modelling of complex biological functions and interactions, and can utilise these technologies to understand IPF.To this end we have assembled an international team to address 3 interlinked objectives:1) Generate a hIPSC model of IPF to understand how SFTPC mutations affect cellular phenotype and gene expression in AE2 cells. There are no known mutations that cause of IPF, however mutations in surfactant protein C (SFTPC) can cause inherited IPF also known as familial IPF, the mechanism however remains elusive. We will generate a stem cell model of familial IPF by taking a skin biopsy from patients with a SFTPC mutation and then turning their skin cells into lung cells using our established protocol. We will then use the cells to study how the mutation causes lung cell damage, fibrosis and to identify new therapeutic targets to treat IPF.2) Model respiratory infection in-vitro to understand the effect of infection on AE2 cells carrying SFTPC mutation. IPF patients have more frequent respiratory infections and >90% mortality rate per infection, how bacterial infection exacerbates IPF is not well understood. Using the SFTPC mutant cells created in Obj. 1 we will use our 3D culture platform to grow lung organoids and then infect them with bacteria or viruses. We will create a profile of changes in gene expression in response to infection and compare this to uninfected cells. This will provide insight into how respiratory infection affects normal lung cell function and importantly deliver insight into the mechanism by which infection exacerbates IPF.3) Model change in ECM composition to understand how ECM impacts cell phenotype. As IPF progresses, the scaffold that holds the lungs together, the extracellular matrix (ECM), dramatically changes, causing the lungs to become stiff and less elastic as well as reducing oxygen absorption. How the changes in ECM affect lung cell function, and whether lung cells actively contribute to further ECM changes has not been well characterised. We will develop our understanding of this process by growing cells created in Obj. 1 in simple 3D gels that will allow us to model how the ECM changes during early and late stages of IPF. We will then assess how these changes affect cell functionality and gene expression. This will provide insight into how ECM influences lung cell function and importantly deliver potential therapeutic targets that aim to prevent or reverse changes to ECM in IPF. These objectives will address poor access to human IPF disease models, and provide insight to the pathogenesis of lung fibrosis and infection in IPF, offering the opportunity to develop exciting new drug targets as well as diagnostic and prognostic markers for the disease. Importantly, this platform could be modified to model other fibrotic lung diseases, and other diseases that have a fibrotic component.