Engineering a 3D Lung Co-culture Platform to Model Epithelial–Fibroblast Interactions in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease (ILD) characterized by progressive fibrosis, irreversible loss of lung elasticity, and chronic respiratory failure, with a mean survival of 3–5 years. The disease is believed to result from repeated alveolar epithelial injury that sustains transforming growth factor-beta (TGF-β) signaling, driving fibroblast-to-myofibroblast differentiation and excessive collagen deposition. Although current IPF models—including animal studies, 2D cultures, and basic 3D systems—have enhanced understanding of disease mechanisms, they inadequately replicate epithelial–fibroblast interactions, extracellular matrix (ECM) remodeling, and epithelial barrier dysfunction. To address this limitation, we engineered a 3D lung co-culture model that simulates the physiological epithelial–fibroblast crosstalk and ECM remodeling characteristic of IPF. Our model embeds fibroblasts within a collagen–hyaluronic acid matrix overlaid with an epithelial monolayer cultured at an air–liquid interface. Basolateral TGF-β exposure generated a profibrotic microenvironment that weakened epithelial barrier integrity and drove myofibroblast differentiation marked by elevated α-SMA and vimentin. Elevated pro-inflammatory cytokine secretion and increased collagen disorganization further demonstrated active fibrogenesis. Together, these features show that our model captures key early events in IPF pathogenesis and offers a versatile platform for next-generation lung-on-a-chip studies in fibrotic disease.