LDLR dysfunction induces LDL accumulation and promotes pulmonary fibrosis

Area of Science:

• Cell Biology
• Molecular Medicine
• Pulmonary Medicine

Background:

• Pulmonary fibrosis (PF) lacks effective treatments due to unclear molecular mechanisms.
• Therapeutic targets for PF remain largely unidentified.

Purpose of the Study:

• To investigate the role of low-density lipoprotein (LDL) and its receptor (LDLR) in the pathogenesis of pulmonary fibrosis.
• To explore LDLR-enhancing strategies as a potential therapeutic approach for PF.

Main Methods:

• Analysis of LDLR expression in lung cells of PF patients and mouse models.
• Assessment of LDL levels in plasma of PF patients.
• In vivo studies using bleomycin-induced PF in wild-type and Ldlr-deficient mice.
• In vitro experiments on cell apoptosis, TGF-β1, and ET-1 production.
• Pharmacological intervention using atorvastatin and alirocumab.

Main Results:

• LDLR expression was altered in PF patients' lung cells, with decreased levels in ATII and fibroblast cells and increased levels in endothelial cells.
• Plasma LDL levels were elevated in PF patients.
• Ldlr-deficient mice showed exacerbated PF, increased apoptosis, and fibroblast-like cell accumulation.
• LDL induced apoptosis and TGF-β1 production; LDLR knockdown induced fibroblast-like cell accumulation and ET-1 expression.
• Pharmacological restoration of LDLR mitigated PF in mice.

Conclusions:

• Disturbed LDL-LDLR metabolism is implicated in the cellular dysfunction observed in pulmonary fibrogenesis.
• LDLR acts as a key mediator in PF development.
• Strategies aimed at enhancing LDLR function may offer therapeutic benefits for pulmonary fibrosis.