Targeted reprogramming of macrophages by inhalable dual-ligand-engineered liposomes via mechano-biochemical signaling coupling to improve acute lung injury.

Acute lung injury (ALI) is characterized by disruption of the alveolar-capillary barrier, uncontrolled inflammation, and pulmonary edema, in which pathogenesis is mostly associated with the biased polarization of alveolar macrophages, macrophage-targeted therapies show great promise in ameliorating ALI but remain challenging. Here, we developed inhalable dual-ligand-engineered liposomes (DLE-Lipos) with single/dual macrophage-targeting ligands (apoptotic 'eat-me' signal: phosphatidylserine (PS), and mannose (MAN)) and tunable Young's modulus (hundreds of Pa vs. ~100 kPa) for reprogramming macrophages to improve ALI. It was found that the modulus of lipos significantly modulated their ligand-mediated macrophage response, including uptake and immunomodulatory effects, and its contribution was even greater than that of surface ligand combination. Low-modulus lipos showed prolonged retention on the macrophage surface, reduced internalization, and enhanced immunomodulatory effects, especially for MAN-PS-Lipo-L. In a murine model of LPS-induced ALI, aerosolized MAN-PS-Lipo-L markedly alleviated lung injury, attenuated inflammatory responses and collagen deposition by 84.4%, restored the lung wet-to-dry ratio toward that of healthy controls, and promoted alveolar macrophage polarization toward an M2-like phenotype without evident systemic toxicity. Transcriptomic analysis further revealed broad transcriptional reprogramming involving mechanosensing, inflammatory, and immune-regulatory pathways, consistent with a proposed mechano-biochemical coupling process associated with modulus-dependent macrophage modulation. Collectively, these findings demonstrate that engineered liposomes with optimization of their surface ligands and mechanical properties can effectively achieve targeted reprogramming of inflammatory macrophages, and provides a promising drug-free, inhalable nanotherapeutic platform for ALI treatment.