Distinct niches within the extracellular matrix dictate fibroblast function in (cell free) 3D lung tissue cultures

Instructive cues from the extracellular matrix (ECM) and their functional interplay with cells play pivotal roles for development, tissue repair, and disease. However, the precise nature of this interplay remains elusive. We used an innovative 3D cell culture ECM model by decellularizing ex vivo lung tissue scaffolds (d3D-LTCs) derived from diseased and healthy mouse lungs, which widely mimics the native (patho)physiological in vivo microenvironment. We successfully repopulated all d3D-LTCs with primary human and murine fibroblasts. The engrafted fibroblasts revealed a striking functional plasticity according to their localization in distinct niches of the d3D-LTCs' ECM: the mesothelium favored the engraftement of cells, alveolar and fibrotic areas reduced cellular migration rates, and regions of airways or vessels generated small, flat cell bodies compared to elongated, spindle-shaped ones in fibrotic or alveolar regions. Moreover, attachment to the d3D-LTCs occurred via focal adhesions, while protein le...