SDC4 and pulmonary fibrosis: Through in vitro and in vivo experiments, this study sought to elucidate the role and mechanisms of the fibrotic ECM in promoting pulmonary fibrosis via SDC4, assess the anti-PF effects of the interfering peptide SDC487-131, evaluate its impact on the interaction between SDC4 and integrin-αvβ1, and refine SDC487-131 to derive a new polypeptide with enhanced anti-pulmonary fibrosis effects.