Matrix crosslinking enhances macrophage adhesion, migration, and inflammatory activation

Area of Science:

• Immunology
• Biomaterials Science
• Cell Biology

Background:

• Macrophages are key innate immune cells with diverse functions.
• Extracellular matrix properties influence macrophage behavior.
• Fibrin, a provisional matrix protein, previously shown to inhibit macrophage inflammatory activation.

Purpose of the Study:

• Investigate the role of matrix stiffness in regulating macrophage activity.
• Manipulate fibrin mechanical properties to modulate macrophage function.
• Understand how physical matrix cues impact macrophage inflammatory responses.

Main Methods:

• Utilized photo-initiated crosslinking to create tunable fibrin gels.
• Employed active microrheology to confirm increased gel stiffness.
• Cultured macrophages on varying stiffness substrates to assess functional changes.

Main Results:

• Matrix crosslinking altered macrophage morphology, integrin expression, and migration.
• Macrophages on stiffer substrates showed increased cell spreading and αM integrin expression.
• Photo-crosslinked fibrin enhanced macrophage inflammatory activation compared to unmodified fibrin.

Conclusions:

• Matrix stiffness is a critical regulator of macrophage functional phenotype.
• Stiffer extracellular matrices can promote macrophage inflammatory activation.
• Findings elucidate how physical matrix properties influence macrophage behavior in inflammation and healing.