Targeted Dual Small Interfering Ribonucleic Acid Delivery via Non‐Viral Polymeric Vectors for Pulmonary Fibrosis Therapy

Abstract Inhibiting the myofibroblast differentiation of lung‐resident mesenchymal stem cells (LR‐MSCs) is a promising yet challenging approach for pulmonary fibrosis (PF) therapy. Here, micelles formed by a graft copolymer of multiple PEGs modified branched polyethylenimine are used for delivering runt‐related transcription factor‐1 (RUNX1) small interfering RNA (siRNA) (siRUNX1) to the lung, aiming to inhibit the myofibroblast differentiation of LR‐MSCs. LR‐MSC targeting is achieved by functionalizing the micelle surface with an anti‐stem‐cell antigen‐1 antibody fragment (Fab′). Consequently, therapeutic benefits are obtained by successful suppression of myofibroblast differentiation of LR‐MSCs in bleomycin‐induced PF model mice treated with siRUNX1‐loaded micelles. Furthermore, an excellent synergistic effect of PF therapy is achieved for this micelle system loaded siRUNX1 and glioma‐associated oncogene homolog‐1 (Gli1) small interfering RNA (siGli1), a traditional anti‐PF siRNA of glioma‐associated oncogene homolog‐1. Hence, this work not only provides RUNX1 as a novel PF therapeutic target, but also as a promising dual siRNA‐loaded nanocarrier system for the therapy of PF.