Monocyte-macrophage differentiation in three dimensional collagen lattice

Human peripheral blood mononuclear cells (PBMC) upon transendothelial migra tion interact with subendothelial matrix components and differentiate into macrophages. In order to study whether the shape of the cells as dictated b y the extracellular matrix can influence monocyte-macrophage (mo-m phi) dif ferentiation, human PBMC were maintained in vitro on a three dimensional co llagen I (COL I) lattice and studied for various macrophage specific functi ons, viz. endocytosis of [I-125]acetyl bovine serum albumin (BSA), expressi on of specific cell surface antigens and expression of matrix metalloprotei nases (MMPs). The cells maintained in three dimensional COL gel exhibited a higher rate of endocytosis of [I-125]acetyl BSA than those on COL-coated p lastic. FACS analysis showed that the mean fluorescence intensity (MFI) cor responding to monocyte specific LPS receptor CD14 was significantly decreas ed while MFI corresponding to macrophage specific transferrin receptor CD71 was significantly increased in cells maintained in vitro on three dimensio nal COL gel compared to two dimensional COL substrata. Expression of macrop hage specific MMPs (gelatinase A and gelatinase B) was significantly high i n cells maintained on COL gel than on COL 1-coated plastic. Appearance of 6 7 kDa gelatinase in the COL,el suggested that induction as well as activati on of MMPs occur when cells are maintained in a three dimensional environme nt. These results indicate that monocytes undergo a rapid rate of different iation when maintained in vitro on three dimensional COL I lattice suggesti ng that apart from the chemical nature of the matrix, the shape of the cell s as provided by the matrix also influences nio-trio differentiation. (C) 2 001 Elsevier Science B.V. All rights reserved.