Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal lung disease with limited therapeutic options. The STING signaling pathway, particularly in alveolar macrophages (AMs), has been identified as a critical driver of fibrosis. However, achieving efficient and selective drug delivery to these pathogenic macrophages in the distal lung represents the major hurdle that hinders its clinical translation. To overcome this, we employed a systematic orthogonal screening strategy to develop a macrophage-targeted lipid nanoparticle (LNP) platform. Our optimized formulation, mCas9/gSting@DOPS, demonstrated over 7-fold greater macrophage expression efficiency compared to commercial formulations and was engineered for precise in vivo Sting1 gene editing. This system leverages surface phosphatidylserine (PS) for selective uptake and encapsulates a CRISPR/Cas9 mRNA payload. Following inhalation, LNPs selectively accumulated in target macrophages within a murine model of pulmonary fibrosis. This targeted delivery resulted in effective Sting1 gene disruption, suppression of downstream STING signaling, and reduced secretion of pro-fibrotic cytokines. Functionally, treatment with mCas9/gSting@DOPS LNPs significantly attenuated collagen deposition, alleviated alveolar collapse, and remodeled the fibrotic immune microenvironment. Notably, this therapeutic approach prolonged survival without evidence of systemic toxicity. Our findings establish that our orthogonally-optimized LNP platform enables potent and clinically viable molecular therapy for IPF by efficiently targeting pulmonary macrophages.
