Interactions between macrophages and oxidized low density lipoprotein in the presence of type I collagen

Article type: Research Article

Authors: Chen, Qi | Wei, Enhui | Chen, Xiuying | Wang, Nan | Jürgens, Günther

Affiliations: Atherosclerosis Research Center, Nanjing Medical University, Nanjing 210029, P.R. China Fax: +86 25 6508960 | Institute of Medical Biochemistry, University of Graz, A‐8010 Graz, Austria Fax: +43 316 380 9121

Abstract: In order to investigate the influence of collagen on the interactions between macrophages and oxidatively modified low density lipoprotein (ox‐LDL), type I collagen was isolated from rat tail tendon and prepared as a gel. The binding of ^{125}I‐ox‐LDL, ^{125}I‐malondialdehyde (MDA)‐LDL and ^{125}I‐acetyl‐LDL to collagen was higher but the binding of ^{125}I‐4‐hydroxynonenal (HNE)‐LDL was lower than that of native ^{125}I‐LDL. When mouse peritoneal macrophages were cultivated on this collagen gel, most of the modified LDL was bound to the collagen gel rather than taken up by macrophages. The amount of modified ^{125}I‐LDL degraded by the macrophages decreased in the presence of the collagen gel. In the absence of gel a similar degree of reduction in degradation of modified ^{125}I‐LDL by macrophages was obtained when the cells were treated with cytochalasin D, an inhibitor of non‐specific phagocytosis. However, the treatment of the macrophages cultivated on the collagen gel with cytochalasin D did not influence the degradation of ^{125}I‐ox‐LDL and ^{125}I‐HNE‐LDL. These results suggest that the uptake of ox‐LDL by macrophages grown on collagen gels is primarily mediated via the scavenger receptors pathway, whereas in the absence of collagen also other mechanisms of uptake are operating.

Keywords: Collagen, macrophages, oxidized low density lipoprotein

Journal: Biofactors, vol. 6, no. 2, pp. 131-138, 1997