Fibronectin fibrils regulate TGF-β1-induced Epithelial-Mesenchymal Transition.

Area of Science:

• Cell Biology
• Biochemistry
• Extracellular Matrix Research

Background:

• Epithelial-Mesenchymal Transition (EMT) involves phenotypic changes crucial for development and disease.
• Both mechanical and growth factor signaling pathways influence EMT.
• The extracellular matrix (ECM) is a potential integration point for these signaling pathways.

Purpose of the Study:

• To investigate the role of fibronectin (FN), an ECM protein, in regulating EMT.
• To elucidate the mechanism by which FN influences EMT, particularly in relation to TGF-β signaling.

Main Methods:

• Inhibition of FN fibrillogenesis.
• Assessment of Transforming Growth Factor-Beta (TGF-β) signaling pathway activation (Smad2).
• Evaluation of cell migration and EMT progression.
• Utilized monoclonal antibodies and FN deletion mutants to block TGF-β1 binding to FN fibrils.

Main Results:

• Inhibition of FN fibrillogenesis blocked TGF-β signaling, reduced cell migration, and inhibited EMT.
• Soluble FN, FN fibrils, or increased contractile forces alone did not induce EMT.
• Blocking latent TGF-β1 binding to FN fibrils prevented EMT progression.

Conclusions:

• FN fibril assembly is essential for localizing TGF-β1 signaling, thereby driving EMT.
• FN plays a novel, critical role in regulating EMT through its interaction with TGF-β1 signaling.
• Targeting FN-TGF-β1 interactions could offer therapeutic strategies for EMT-related conditions.