EDA Fibronectin Microarchitecture and YAP Translocation during Wound Closure.

Area of Science:

• Biochemistry
• Cell Biology
• Tissue Engineering

Background:

• Fibronectin (Fn) is a key extracellular matrix protein.
• The Extra domain A (EDA) Fn isoform is crucial for tissue repair but linked to both regeneration and fibrosis.
• Cellular mechanosensing, particularly via yes-associated protein (YAP), influences wound healing outcomes.

Purpose of the Study:

• To investigate how EDA Fn organization modulates YAP translocation during normal and fibrotic wound closure.
• To explore the role of EDA Fn matrix organization in mediating regenerative versus fibrotic repair.
• To assess the impact of microenvironmental stiffness on EDA Fn assembly and YAP activity.

Main Methods:

• Human dermal fibroblasts cultured on soft (18 kPa) and stiff (146 kPa) polydimethylsiloxane substrates mimicking normal and fibrotic wounds.
• Pharmacological inhibition of EDA Fn binding (Irigenin) and YAP activity (CA3).
• Analysis of EDA Fn matrix organization (fiber alignment and thickness) and YAP translocation.

Main Results:

• Stiffer substrates led to aligned EDA Fn matrices with thinner fibers, indicating increased tension.
• Blocking EDA Fn binding or YAP activity resulted in randomly organized, thicker EDA Fn fibers, reducing tension.
• Fibroblasts on soft substrates showed increased YAP activity, while those on stiff substrates showed decreased YAP activity.
• Inhibiting EDA Fn binding or YAP on stiff substrates restored increased YAP activity.

Conclusions:

• EDA Fn organization and YAP signaling are interconnected and influenced by microenvironmental stiffness.
• Disrupted signaling between EDA Fn organization and YAP translocation may contribute to fibrotic wound closure.
• Restoring normal EDA Fn matrix organization could potentially shift fibrotic repair towards regeneration.