Functional metabolomics revealed pyroglutamic acid may play a key role in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible respiratory disease with poor survival rates. Despite significant research efforts, IPF still lacks a curative treatment. Excessive epithelial-mesenchymal transition (EMT) contributes to approximately one-third of fibroblasts in pulmonary fibrosis and plays a critical role in IPF pathogenesis. Identifying factors that regulate EMT is essential for developing effective therapeutic strategies for IPF. In this study, functional metabolomics revealed significant alterations in multiple metabolites in transforming growth factor-beta 1 (TGF-β1)-induced A549 cells, with pyroglutamic acid and 5-oxoprolinase (OPLAH) being identified as the most critical factors. Cellular experiments demonstrated that pyroglutamic acid effectively inhibited TGF-β1-induced EMT in A549 cells. Mechanistically, pyroglutamic acid inhibited IPF by suppressing EMT through the inhibition of Smad2/3 expression in TGF-β1-induced A549 cells. Bioinformatics analysis further elucidated the pyroglutamate is a potential metabolite that inhibits EMT. In addition, this study is the first to highlight the pivotal role of pyroglutamic acid and OPLAH in regulating EMT in IPF, offering novel insights into the metabolic mechanisms involved in IPF inhibition and providing a foundation for developing innovative therapeutic approaches for IPF.