Strict control of
iron homeostasis is critical for the maintenance of normal lung function.
Iron accumulates in the lungs of patients with
idiopathic pulmonary fibrosis (PF), but the characteristics of
iron metabolism in the pathogenesis of PF and related targeting
therapeutics are not well studied. In this study, we investigated the cellular and molecular characteristics of
iron metabolism in fibrotic lungs and further explored the efficacy of
clioquinol (CQ) for the treatment of PF as well as its functional mechanism.
Iron aggregates accumulated in the lungs of patients with idiopathic PF, and FTL (
ferritin light chain) transcripts were increased in their pulmonary fibroblasts. In the
bleomycin (BLM)-induced PF (BLM-PF) mouse model, pulmonary
iron accumulation is a very early and concomitant event of PF. Labile
iron pool levels in both fibroblasts and macrophages from the BLM-PF model were elevated, and
iron metabolism was dysregulated. CQ attenuated PF induced by BLM and
FITC, and
iron-saturated CQ did not alleviate BLM-PF. Furthermore, CQ inhibited the activation of fibroblasts, including proliferation, fibrotic differentiation, proinflammatory
cytokine secretion, and migration. In conclusion, our study demonstrated that CQ, acting as an
iron chelator, attenuates experimental PF through inactivation of fibroblasts, providing support for targeting
iron metabolism as a basis for PF treatment.