Dipeptidyl Peptidase-4-Mediated Fibronectin Processing Evokes a Profibrotic Extracellular Matrix

Area of Science:

• Extracellular Matrix Biology
• Fibrosis Pathogenesis
• Dermatology

Background:

• Fibronectin is crucial for organizing the extracellular matrix (ECM), including collagen and fibrillin.
• Altered fibronectin deposition is an early event in fibrotic diseases, leading to disorganized ECM.
• Recessive dystrophic epidermolysis bullosa serves as a model for severe dermal fibrosis.

Purpose of the Study:

• To investigate the role of fibronectin's ECM-organizational capacity in fibrosis development.
• To explore the link between dipeptidyl peptidase-4 (DPP-4) and fibronectin deposition in fibrosis.
• To identify potential therapeutic strategies targeting DPP-4 for fibrotic conditions.

Main Methods:

• Culturing fibroblasts from recessive dystrophic epidermolysis bullosa patients in 2D and 3D.
• Analyzing fibronectin, fibrillin, and collagen I deposition.
• Utilizing proteomics, DPP-4 inhibitors, and mutagenesis studies.

Main Results:

• Fibroblasts from patients showed dysregulated fibronectin deposition.
• Increased profibrotic DPP-4-positive fibroblasts correlated with altered fibronectin deposition.
• DPP-4 inhibition normalized fibronectin, fibrillin, and collagen I deposition.
• DPP-4 modulates ECM deposition via proteolysis of the fibronectin N-terminus.

Conclusions:

• DPP-4 plays a key role in fibrotic ECM dysregulation.
• Targeting DPP-4 can restore normal ECM assembly and offers a potential therapeutic approach for fibrosis.
• This study elucidates the mechanism of DPP-4 in fibronectin-guided ECM assembly in health and disease.