Leukocyte interleukins induce cultured endothelial cells to produce a highly organized, glycosaminoglycan-rich pericellular matrix.

Abstract

Interleukins have a dramatic effect on extracellular matrix production by cultured endothelial cells. Human umbilical vein endothelial cells incubated with growth media conditioned by lectin-activated human peripheral blood mononuclear leukocytes undergo marked changes in cell shape and elaborate a highly organized extracellular material that is not detectable in untreated cultures. It is not recognizable by EM unless the cationic dye, Alcian blue, is added to the fixative. It is visualized as a network of branching and anastomosing fibrils of various thickness that can be resolved into bundles of fine filaments. It is associated with the cell surface, extends between contiguous cells, and coats the culture substrate. It is removed by digestion with glycosaminoglycan-degrading enzymes, such as crude heparinase and chondroitinase ABC. Soluble factors released by activated peripheral blood mononuclear leukocytes (interleukins) stimulate cultured human umbilical vein endothelial cells to produce a highly structured pericellular matrix containing glycosaminoglycans (probably chondroitin sulfate and/or hyaluronic acid) as a major constituent. This phenomenon could correspond to an early step of angiogenesis as observed in vivo as a consequence of interleukin release.