Fibronectin stimulates macrophage uptake of low density lipoprotein-heparin-collagen complexes.

TitleFibronectin stimulates macrophage uptake of low density lipoprotein-heparin-collagen complexes.
Publication TypeJournal Article
Year of Publication1988
AuthorsFalcone DJ, Salisbury BG
Date Published1988 May-Jun
KeywordsAnimals, Apolipoproteins, Cholesterol Esters, Collagen, Endocytosis, Female, Fibronectins, Heparin, Humans, Lipoproteins, LDL, Macrophages, Mice, Mice, Inbred BALB C, Opsonin Proteins, Phagocytosis, Protein Binding, Stimulation, Chemical

In this study, we investigated whether fibronectin will enhance macrophage uptake of particulate complexes of low density lipoproteins (LDL), heparin, and fibrillar collagen and whether fibronectin's opsonic effect could be modulated by the heparin component in these model matrices. We isolated a heparin fraction (HepFn) based on its affinity to fibronectin. HepFn appeared more charged than unfractionated heparin, as evidenced by enhanced electrophoretic mobility and ability to effect a cathodic shift in the electrophoretic migration of fibronectin. HepFn lacked the smaller molecular weight species present in unfractionated heparin. Macrophage endocytosis of LDL-heparin-collagen complexes, as evidenced by the intracellular accumulation of LDL-derived cholesteryl esters and endogenously synthesized cholesteryl esters, was enhanced by fibronectin. When LDL matrix complexes were prepared with HepFn, fibronectin's opsonic properties were significantly enhanced. F(ab)2 fragments of anti-fibronectin, capable of inhibiting fibronectin's opsonization of gelatin-derivatized latex particles, inhibited the fibronectin-dependent stimulation of cholesteryl ester synthesis by macrophages exposed to LDL-HepFn-collagen complexes. Thus, fibronectin stimulates macrophage endocytosis of LDL matrix complexes. The affinity of the constituent glycosaminoglycan for fibronectin is important in the regulation of this phenomenon.

Alternate JournalArteriosclerosis
PubMed ID3370022
Grant ListHL-18828 / HL / NHLBI NIH HHS / United States
HL-31099 / HL / NHLBI NIH HHS / United States
HL-31271 / HL / NHLBI NIH HHS / United States
Related Faculty: 
Domenick J. Falcone, Ph.D.

Pathology & Laboratory Medicine 1300 York Avenue New York, NY 10065 Phone: (212) 746-6464
Surgical Pathology: (212) 746-2700