Monocyte-macrophage differentiation in three dimensional collagen lattice

Area of Science:

• Cell Biology
• Immunology
• Biomaterials Science

Background:

• Human peripheral blood mononuclear cells (PBMC) differentiate into macrophages after migrating through the endothelium.
• The extracellular matrix (ECM) influences cell behavior and differentiation.

Purpose of the Study:

• To investigate if cell shape, dictated by the ECM, influences monocyte-macrophage (mo-m(phi)) differentiation.
• To compare mo-m(phi) differentiation in 3D collagen I (COL I) versus 2D COL-coated substrates.

Main Methods:

• Human PBMC cultured in vitro on 3D COL I lattice and 2D COL-coated plastic.
• Assessed macrophage-specific functions: endocytosis of [(125)I]acetyl bovine serum albumin (BSA), cell surface antigen expression (FACS), and matrix metalloproteinase (MMP) expression.

Main Results:

• Cells in 3D COL gel showed higher [(125)I]acetyl BSA endocytosis than 2D cultures.
• CD14 expression decreased, while CD71 expression increased in 3D COL gel, indicating differentiation.
• Macrophage-specific MMPs (gelatinase A and B) were significantly higher in 3D cultures, with 67 kDa gelatinase appearance suggesting induction and activation.

Conclusions:

• Monocytes differentiate more rapidly in a 3D COL I lattice in vitro.
• Both the chemical composition and the physical shape provided by the ECM influence monocyte-macrophage differentiation.