Integrin-β aggravates paraquat-induced pulmonary fibrosis by activation of FAK/ ERK1/2 pathway depending on fibrotic ECM.

BACKGROUND

Irreversible pulmonary fibrosis induced by paraquat is the most prevalent cause of death in patients with paraquat poisoning. Pulmonary fibrosis is characterized by abnormal deposition of extracellular matrix (ECM). Currently, the role of fibrotic ECM microenvironment in paraquat-induced pulmonary fibrosis has not been established.

METHODS

Rat pulmonary fibrosis model was induced by paraquat, ATN-161 (an integrin-β antagonist) was given to investigate their effect on Rat survival and pulmonary fibrosis. Lungs were decellularized to generate normal and fibrotic acellular ECM scaffolds using Triton and SDS. Fibroblasts were cocultured with ECM scaffolds to established 3D culture systems to investigate the relationship between fibrotic ECM and the differentiation of fibroblasts. Then we explored the effect of fibrotic ECM microenvironment systematically promoting on integrin-β1/FAK/ERK1/2 pathway and established 3D culture systems to investigate the relationship between fibrotic ECM and the differentiation of fibroblasts.

RESULTS

Antagonism of integrin-β could alleviate paraquat-induced pulmonary fibrosis and ameliorate survival status of rats. Compared to normal ECM, fibrotic extracellular microenvironment promoted the differentiation of fibroblasts to myofibroblasts. Antagonism of integrin-β could also ameliorate the promotion of fibrotic extracellular microenvironment on differentiation of fibroblasts to myofibroblasts. Fibrotic ECM microenvironment promotes fibroblasts transforming into myofibroblasts through integrin-β/FAK/ERK1/2 signaling pathway. Moreover, this phenomenon holds independent on exogenous integrin-β.

CONCLUSIONS

Activation of integrin-β/FAK/ERK1/2 pathway aggravates paraquat-induced pulmonary fibrosis depend on fibrotic ECM and integrin-β may be a prospective therapeutic target for paraquat-induced pulmonary fibrosis in the future.