Wnt3a‐Loaded Extracellular Vesicles Promote Alveolar Epithelial Regeneration after Lung Injury

Compromised regeneration resulting from the deactivation of Wnt/β‐catenin signaling contributes to the progression of chronic obstructive pulmonary disease (COPD) with limited therapeutic options. Extracellular cytokine‐induced Wnt‐based signaling provides an alternative option for COPD treatment. However, the hydrophobic nature of Wnt proteins limits their purification and use. This study devises a strategy to deliver the membrane‐bound wingless‐type MMTV integration site family, member 3A (Wnt3a) over a long distance by anchoring it to the surface of extracellular vesicles (EVs). The newly engineered Wnt3a(WG) EVs are generated by co‐expressing Wnt3a with two genes encoding the membrane protein, WLS, and an engineered glypican, GPC6(ΔGPI)‐C1C2. The bioactivity of Wnt3a(WG) EVs is validated using a TOPFlash assay and a mesoderm differentiation model of human pluripotent stem cells. Wnt3a(WG) EVs activate Wnt signaling and promote cell growth following human alveolar epithelial cell injury. In an elastase‐induced emphysema model, impaired pulmonary function and enlarged airspace are greatly restored by the intravenous delivery of Wnt3a(WG) EVs. Single‐cell RNA sequencing–based analyses further highlight that Wnt3a(WG) EV‐activated regenerative programs are responsible for its beneficial effects. These findings suggest that EV‐based Wnt3a delivery represents a novel therapeutic strategy for lung repair and regeneration after injury.