Matrix-Bound Nanovesicles Recapitulate Extracellular Matrix Effects on Macrophage Phenotype.

Area of Science:

• Biomaterials Science
• Immunology
• Tissue Engineering

Background:

• Macrophage response to biomaterials critically impacts tissue repair outcomes.
• Extracellular matrix (ECM) scaffolds can guide macrophages toward a regulatory phenotype, promoting constructive tissue repair.
• The precise mechanisms by which ECM scaffolds modulate macrophage phenotype remain unclear.

Purpose of the Study:

• To investigate the role of matrix-bound nanovesicles (MBV) in mediating the immunomodulatory effects of ECM biomaterials.
• To identify specific microRNAs (miRNAs) within MBV responsible for regulating macrophage phenotype.
• To elucidate the contribution of MBV-associated miRNAs to the anti-inflammatory effects of ECM scaffolds.

Main Methods:

• Isolation and characterization of MBV from porcine urinary bladder and small intestinal submucosa ECM scaffolds.
• Analysis of miRNA content within isolated MBV.
• Inhibition of specific miRNAs in macrophages and assessment of resulting phenotypic changes.
• Evaluation of gene and protein expression profiles to determine macrophage phenotype.

Main Results:

• MBV isolated from ECM scaffolds recapitulated the scaffold's ability to modulate macrophage behavior.
• MBV were enriched in specific miRNAs: miRNA125b-5p, miRNA143-3p, and miRNA145-5p.
• Inhibiting these miRNAs in macrophages led to a proinflammatory gene and protein expression profile.
• MBV and their miRNA cargo are key mediators of ECM scaffold-induced macrophage phenotype modulation.

Conclusions:

• MBV are critical effectors of ECM biomaterial-mediated macrophage polarization.
• Specific miRNAs (miRNA125b-5p, miRNA143-3p, miRNA145-5p) within MBV are essential for inducing an anti-inflammatory macrophage phenotype.
• MBV-associated miRNAs represent a novel mechanism by which ECM scaffolds promote tissue regeneration.