Tetrahedral framework nucleic acids loaded siCCR2 restrains M1 macrophage polarization to ameliorate pulmonary fibrosis in chemoradiation-induced murine model

Idiopathic pulmonary fibrosis (IPF) is a chronic lethal disease in the absence of demonstrated efficacy for preventing progression. Although macrophage-mediated alveolitis is determined to participate myofibrotic transition during disease development, the paradigm of continuous macrophage polarization is still under-explored due to lack of proper animal-models. Here, by integrating 2.5 U/kg intratracheally Bleomycin administration and 10 Gray thorax irradiation at day 7, we generated a murine model with continuously alveolitis-mediated fibrosis, which mimics most of the clinical features of our involved IPF patients. In combination with data from scRNA-seq of patients and murine IPF model, a decisive role of CCL2/CCR2 axis in driving M1 macrophage polarization was revealed. And M1 macrophage was further confirmed to boost alveolitis in leading myofibroblast activation. Multiple sticky-end tetrahedral Framework Nucleic Acids conjunct with quadruple ccr2-siRNA (FNA-siCCR2) was synthesized in targeting M1 macrophages. FNA-siCCR2 successfully blocked macrophage accumulation in pulmonary parenchyma of IPF murine model thus prevent myofibroblast activation and led to disease remitting. Overall, our studies lay the groundwork to develop novel IPF murine model, reveal M1 macrophages as potential therapeutic target, and establish new treatment strategy by using FNA-siCCR2, which are highly relevant to clinical scenarios and translational researches in the field of IPF.