BACKGROUND: Epithelial-mesenchymal transition (EMT) is regarded as a key process in repair of airway epithelium after injury. Forkhead Box C2 (FOXC2) is a transcription factor involved in EMT process, whether it is involved in repair of bronchial epithelium remains unknown. METHODS: C57BL/6 mice were subjected to intraperitoneal injection with naphthalene (NAPH
200 mg/kg) to induce airway injury model. qPCR, immunoblot and FOXC2 immunohistochemistry assays were conducted to detect the expression of FOXC2 in bronchial epithelium. To explore the function of FOXC2 in NAPH-induced airway injury, the mice were given intratracheal administration of shFOXC2- or shNC-lentivirus particles, followed by NAPH treatment. Hematoxylin-and-eosin staining was used to assess the histopathology of the bronchial epithelium. Immunofluorescence analysis of CCSP, a club cell marker confirmed the CCSP expression in bronchial epithelium. Immunoblot and immunofluorescence assays determined the expression of E-cadherin, vimentin, and N-cadherin. In mouse primary bronchial epithelial cells (PBECs), we overexpressed and silenced FOXC2 by lentivirus particles, respectively. Cell migration was analyzed using wound healing assay. Immunoblot assays determined the E-cadherin, vimentin, FN-EDA expression in TGF-β1-induced PBECs. mRNA sequencing (mRNA-seq) and FOXC2 ChIP sequencing (ChIP-seq) to reveal the downstream genes of FOXC2 in TGF-β1-induced PBECs. Luciferase assay, ChIP-PCR and functional rescue experiments were performed to confirm the interaction of FOXC2/formin binding protein 1 (FNBP1) in TGF-β1-induced PBECs. RESULTS: FOXC2 expression was up-regulated in the lung tissues of mice at 2, 3 and 6 days post-NAPH. FOXC2 knockdown in bronchial epithelium of mice delayed CCSP CONCLUSIONS: These data highlight the important function of FOXC2 as a regulator in repair of bronchial epithelium after injury.