Pulmonary fibrosis results from dysregulated lung repair and involves multiple cell types. The role of endothelial cells (EC) in lung fibrosis is poorly understood. Using single cell RNA-sequencing we identified endothelial transcription factors involved in lung fibrogenesis, including FOXF1, SMAD6, ETV6 and LEF1. Focusing on FOXF1, we found that FOXF1 is decreased in EC within human idiopathic pulmonary fibrosis (IPF) and mouse bleomycin-injured lungs. Endothelial-specific Foxf1 inhibition in mice increased collagen depositions, promoted lung inflammation, and impaired R-Ras signaling. In vitro, FOXF1-deficient EC increased proliferation, invasion and activation of human lung fibroblasts, and stimulated macrophage migration by secreting IL-6, TNFα, CCL2 and CXCL1. FOXF1 inhibited TNFα and CCL2 through direct transcriptional activation of Rras gene promoter. Transgenic overexpression or endothelial-specific nanoparticle delivery of Foxf1 cDNA decreased pulmonary fibrosis in bleomycin-injured mice. Nanoparticle delivery of FOXF1 cDNA can be considered for future therapies in IPF.

肺纤维化是由肺修复失调引起的，涉及多种细胞类型。内皮细胞（EC）在肺纤维化中的作用尚不清楚。利用单细胞 RNA 测序，我们鉴定了参与肺纤维化的内皮转录因子，包括 FOXF1、SMAD6、ETV6 和 LEF1。重点关注 FOXF1，我们发现 FOXF1 在人特发性肺纤维化 (IPF) 和小鼠博莱霉素损伤肺内的 EC 中减少。小鼠体内内皮特异性 Foxf1 抑制会增加胶原蛋白沉积，促进肺部炎症，并损害 R-Ras 信号传导。在体外，FOXF1缺陷的EC增加人肺成纤维细胞的增殖、侵袭和活化，并通过分泌IL-6、TNFα、CCL2和CXCL1刺激巨噬细胞迁移。 FOXF1 通过直接转录激活 Rras 基因启动子来抑制 TNFα 和 CCL2。 Foxf1 cDNA 的转基因过表达或内皮特异性纳米颗粒递送可减少博莱霉素损伤小鼠的肺纤维化。 FOXF1 cDNA 的纳米颗粒递送可考虑用于 IPF 的未来治疗。