Dynamic tensile conditioning of mesenchymal stem cell-laden auxetic scaffolds for enhanced YAP-dependent miR-30 enrichment in extracellular vesicles for pulmonary fibrosis therapy.

Mesenchymal stem cell-derived extracellular vesicles are promising for treating pulmonary fibrosis. However, the generation of extracellular vesicles (EVs) bearing potent, specific therapeutic cargo remains a significant clinical challenge. This study aims to demonstrate how a material-instructive strategy can be utilized to engineer cargo-specific EVs by precisely mimicking the physiological breathing motion of the lung microenvironment. A dynamic culture system was developed by combining a photo-crosslinkable lung decellularized extracellular matrix with an auxetic scaffold. Mesenchymal stem cells (MSCs) were cultured on these scaffolds under dynamic stretching. The dynamically conditioned EVs (dEVs) were then collected, and their therapeutic mechanisms and efficacy were evaluated both in vitro and in vivo using bleomycin-treated human pulmonary fibroblasts and a bleomycin-induced rat pulmonary fibrosis model, respectively. Dynamic stretching on auxetic scaffolds enhanced MSC mechanotransduction, as indicated by the upregulation and nuclear accumulation of YAP. This mechanical activation drove a YAP-dependent biogenesis pathway, leading to the selective enrichment of miR-30 in dEVs. In vivo administration of dEVs effectively restored lung architecture and attenuated collagen deposition. Mechanistically, dEV-derived miR-30 exerted dual therapeutic effects by directly inhibiting myofibroblast activation and promoting the macrophage phenotype switch from pro-inflammatory M1 to anti-inflammatory M2. Furthermore, the EVs successfully restored mitochondrial homeostasis in damaged cells, thereby supporting tissue repair. EVs engineered with miR-30 mimics fully recapitulated the potent therapeutic effects of dEVs, significantly outperforming miR-100. This study successfully established an auxetic dECM scaffold-based mechanogenetic platform to engineer cargo-specific EVs. The findings indicate that mechanical priming optimizes EV therapeutic efficacy, highlighting the YAP/miR-30 axis and mitochondrial restoration as key targets for alleviating pulmonary fibrosis.