Acute toxicological study: EZY ‐1 with potent therapeutic effects of idiopathic pulmonary fibrosis and its mechanisms

Abstract

EZY‐1 is an antifibrosis peptide purified from Eucheuma. In this study, we explored the acute toxicology of EZY‐1 and the signaling pathways involved in its antifibrotic role. The mouse model of pulmonary fibrosis was induced by bleomycin. Pathological changes in lung tissue could be effectively inhibited by EZY‐1. Acute toxicity and cell proliferation tests indicated that EZY‐1 had no apparent toxicity to mice and cells. We identified proteins that could bind directly to EZY‐1 in vitro on the basis of liquid chromatography–tandem mass spectrometry and bioinformatics analysis. EZY‐1 inhibited pulmonary fibrosis via Wnt/β‐catenin, transforming growth factor (TGF)‐β/Smad, phosphoinositide 3‐kinase/protein kinase B/ mammalian target of rapamycin, and activator of transcription 3 and Janus kinase 2/signal transducer pathways. A transwell micropore experiment showed that EZY‐1 could inhibit cell migration and invasion. Western blotting analysis on transforming growth factor‐β1 (TGF‐β1)‐induced A549 pulmonary fibrosis cell model suggested that EZY‐1 could downregulate p‐Smad3 (Ser423/Ser425), Smad4, β‐catenin, vimentin, and N‐cadherin expression. ELISA showed that EZY‐1 could inhibit collagen‐I secretion. EZY‐1 alleviated idiopathic pulmonary fibrosis (IPF) through regulating TGF‐β/Smad pathways, epithelial‐mesenchymal transition processes, and collagen secretion, which provides a potential foundation for theoretical development of EZY‐1 as a potential drug against IPF. Practical applications We isolated a new 16‐amino‐acid peptide derived from the polypeptide extract of Eucheuma, named EZY‐1. In vitro and in vivo assays show peptide EZY‐1 is safe. The EZY‐1 peptide alleviates IPF at lower doses than pirfenidone. EZY‐1 alleviated idiopathic pulmonary fibrosis (IPF) through regulating TGF‐β/Smad pathways, epithelial‐mesenchymal transition (EMT) processes, and collagen secretion, which provides a theoretical basis for the development of EZY‐1 as a potential drug against IPF.