Use of biomaterials to tissue engineer 3D models with lung organoids for in-vitro disease modelling

Lung disease is increasingly prevalent in the UK, many developing debilitating respiratory illnesses e.g. Chronic Obstructive Pulmonary Disease (COPD). No cure exists for COPD, a chronic inflammatory disease associated with small airway fibrosis and only palliative bronchodilator treatments are available. Cells crosstalk with their microenvironment, dictating profile and drive towards a diseased state. 3D models utilise this cross-talk, involving both cell-to-cell and cell-to-extracellular matrix (ECM). ECM in COPD stiffens over time and more models need to reflect subsequent developing mechanical stress. I hypothesise that by inducing stiffness into a 3D model’s biosynthetic matrix will replicate fibrosis onset and alter bronchial epithelial cell function. A 3D model was created using airway bronchosphere organoids derived from human bronchial epithelial cell culture in Matrigel®. Bronchospheres were encapsulated into the model’s matrix, photocured to biomimick lung ECM using photoinitiators, bioinert poly(ethylene glycol) diacrylate and Matrigel®. Various ECM stiffnesses can then be selected to visualise downstream effects on airway epithelial cell profile and function. Upregulation of proliferative markers SOX2 and MKI67 were noted during 72-hour analysis of organoid RNA from stiffened matrices using RT-qPCR, compared to control (Matrigel® only). Preliminary further analysis suggests a replicating upregulated trend of SOX2 and MKI67 expression when matrix stiffness is induced well above normal healthy lung young’s modulus. This links to stimulated cellular mechanotransduction signalling in bronchospheres correlating with applied physical forces experienced via mechanical stress.