AXL-GAS6/PROS1 Interaction: A Critical Switch Between Aberrant- and Healthy Repair Following Alveolar Lung Injury

Abstract

RationaleIdiopathic pulmonary fibrosis (IPF) is a progressive lung disease characterized by aberrant alveolar repair and excessive fibrosis. The TAM-family receptor tyrosine kinase AXL, activated by GAS6 and PROS1, is implicated in tissue remodeling, but ligand-specific AXL signaling during alveolar repair remains poorly defined. ObjectivesTo investigate ligand specific AXL signaling in IPF and how it impacts epithelial proliferation and repair after alveolar injury in-vivo and in-vitro. MethodsSingle cell RNA sequencing was utilized to understand cell specific expression patterns in IPF patients, followed by functional studies in primary human cell culture and functional spatial digital profiling (FuncOmap) analysis in patient tissue. Longitudinal assessment of repair process after alveolar-specific injury in-vivo was used to complement the in-vitro approach. ResultsAXL expression showed enrichment in basal and aberrant basaloid cells of IPF patients. In-vitro GAS6 increased proliferation of basal cells, while PROS1 counteracted this effect. FuncOmap analysis demonstrates direct in-situ interactions between AXL and both ligands, providing evidence for biological relevance. Investigating longitudinal repair processes in-vivo revealed dynamic regulation of AXL ligands as well as AXL. ConclusionsThese findings highlight the importance of ligand-specific AXL signaling in lung repair and suggest that it dysregulation may contribute to IPF pathogenesis, offering potential therapeutic targets for restoring normal repair processes.