A bioengineered extracellular matrix reverts disease phenotype in COPD fibroblasts

The extracellular matrix (ECM) is key to maintain tissue homeostasis, and its dysregulation has a prominent role in the progression of chronic obstructive pulmonary disease (COPD). This is especially notable in emphysema, where the degradation of the ECM in the alveolar walls leads to the loss of support to the alveolar cells and to the disruption of the epithelial layer. Therefore, we propose that restoring the mechanical and biochemical support of the ECM will revert the disease phenotype. As a first step, given the relevance of alveolar fibroblasts in directing tissue repair, we aimed to elucidate the interaction of these cells with an elastin-like (EL) hydrogel that recapitulates the main features of the native alveolar ECM. We cultured parenchymal lung fibroblasts isolated from COPD GOLD IV patients (n=8) and healthy donors (n=8) inside EL hydrogels (3D) and on regular tissue culture plates (2D). Metabolic activity was measured on days 1 and 5, and samples collected for bulk RNA-sequencing on day 7. We found that the microenvironment (3D vs. 2D), and not the disease status, was the major driver for differences in gene expression. COPD fibroblasts were more similar to healthy ones in 3D than in 2D, and enrichment analyses showed upregulation of ECM organization pathways in 3D. For instance, COL4A6, LAMA3, MFAP4 and BMP5 genes were downregulated in COPD fibroblasts in 2D, but their expression was reverted when cultured in 3D to levels found in healthy fibroblasts. Overall, our study highlights the impact of the microenvironment on fibroblast behavior and the capacity of EL hydrogels to revert the disease phenotype in COPD fibroblasts.