Targeting LCN2 attenuates abnormal lymphatic remodeling and SiO2 induced pulmonary fibrosis

Abstract Background Long-term exposure to respirable crystalline free silica (SiO 2 ) is one of the most common and persistent hazards in occupational environments, leading to silicosis and causing progressive fibrotic lung disease, although its fibrogenic molecular mechanisms have not yet been fully elucidated. Objective Objective: This study aims to investigate the role of LCN2 in silica-induced pulmonary fibrosis, with a focus on its regulatory effect on pathological lymphangiogenesis and the underlying molecular mechanisms. Methods To investigate the regulatory role of LCN2 in silica-induced lymphangiogenesis and fibrosis, serum levels of LCN2 and VEGF-C were measured by ELISA in 73 silicosis patients and 15 healthy controls. A silicosis mouse model was established by intratracheal instillation of SiO₂, and the effects of the LCN2 inhibitor ZINC00640089 were evaluated by histopathological staining (HE, VG, and Sirius red), micro-CT imaging, and Western blot analysis of fibrosis and lymphangiogenesis-related markers. Additionally, RNA sequencing was performed to identify differentially expressed genes and signaling pathways modulated by ZINC00640089. To further validate the functional role of LCN2 in lymphatic endothelial cells, in vitro scratch assays and Matrigel tube formation assays were conducted using human lymphatic endothelial cells (HLECs). Results Serum LCN2 and VEGF-C were significantly elevated in silicosis patients. In the silicosis mouse model, ZINC00640089 attenuated pulmonary fibrosis and inflammatory infiltration, accompanied by downregulation of VEGF-C, VEGFR-3, and LYVE-1. Transcriptomic analysis revealed that ZINC00640089 modulated pathways related to inflammation and lymphangiogenesis, including VEGF signaling. Immunofluorescence confirmed LCN2 colocalization with LYVE-1 in lung tissues. In vitro, ZINC00640089 suppressed SiO₂-induced HLEC migration and tube formation. Conclusion This study demonstrates that targeting LCN2 can prevent abnormal lymphatic remodeling and alleviate SiO₂‑induced pulmonary fibrosis, providing a promising therapeutic strategy for silicosis.