Flt1 produced by lung endothelial cells impairs ATII cell transdifferentiation and repair in pulmonary fibrosis

• Published in: Cell death & disease Vol. 14; no. 7; p. 437
• Main Authors: Volpe, Maria Concetta, Ciucci, Giulio, Zandomenego, Giulia, Vuerich, Roman, Ring, Nadja Anneliese Ruth, Vodret, Simone, Salton, Francesco, Marchesan, Pietro, Braga, Luca, Marcuzzo, Thomas, Bussani, Rossana, Colliva, Andrea, Piazza, Silvano, Confalonieri, Marco, Zacchigna, Serena
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.07.2023; Springer Nature B.V; Nature Publishing Group
• Subjects: 13/1; 13/109; 13/89; 14/19; 14/63; 38/77; 631/532/2118; 631/61/490; 631/80/304; 64; 64/110; 64/60; 692/699/1785; 82/58; Alveolar Epithelial Cells - metabolism; Alveoli; Antibodies; Biochemistry; Biomedical and Life Sciences; Cell Biology; Cell Culture; Cell differentiation; Cell Transdifferentiation; Endothelial cells; Endothelial Cells - metabolism; Fibrosis; Gas exchange; Homeostasis; Humans; Immunology; Life Sciences; Lung - metabolism; Lung diseases; MicroRNAs; MicroRNAs - genetics; MicroRNAs - metabolism; miRNA; Paracrine signalling; Pulmonary fibrosis; Pulmonary Fibrosis - metabolism; Therapeutic targets; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - metabolism; Vascular Endothelial Growth Factor Receptor-1 - genetics; Vascular Endothelial Growth Factor Receptor-1 - metabolism
• ISSN: 2041-4889; 2041-4889
• DOI: 10.1038/s41419-023-05962-2

Pulmonary fibrosis is a devastating disease, in which fibrotic tissue progressively replaces lung alveolar structure, resulting in chronic respiratory failure. Alveolar type II cells act as epithelial stem cells, being able to transdifferentiate into alveolar type I cells, which mediate gas exchange, thus contributing to lung homeostasis and repair after damage. Impaired epithelial transdifferentiation is emerging as a major pathogenetic mechanism driving both onset and progression of fibrosis in the lung. Here, we show that lung endothelial cells secrete angiocrine factors that regulate alveolar cell differentiation. Specifically, we build on our previous data on the anti-fibrotic microRNA-200c and identify the Vascular Endothelial Growth Factor receptor 1, also named Flt1 , as its main functional target in endothelial cells. Endothelial-specific knockout of Flt1 reproduces the anti-fibrotic effect of microRNA-200c against pulmonary fibrosis and results in the secretion of a pool of soluble factors and matrix components able to promote epithelial transdifferentiation in a paracrine manner. Collectively, these data indicate the existence of a complex endothelial-epithelial paracrine crosstalk in vitro and in vivo and position lung endothelial cells as a relevant therapeutic target in the fight against pulmonary fibrosis.