title: Fc-gamma receptor cross-linking by immune complexes induces matrix metalloproteinase-1 in U937 cells via mitogen-activated protein kinase.
abstract: Matrix metalloproteinase-1 (MMP-1) secreted by macrophages potentially contributes to plaque rupture. Because large quantities of immunoglobulin G and ICs (ICs), including low density lipoprotein-containing ICs (LDL-ICs), are present in atherosclerotic lesions, we examined the effect of LDL-ICs on macrophage MMP-1 expression. With the use of ICs prepared with human LDL and rabbit anti-LDL antiserum, our enzyme-linked immunosorbent assays and Northern blots showed that MMP-1 secretion and expression by U937 histiocytes were induced by LDL-ICs. Furthermore, our results showed that blocking of Fc-gamma receptor I and II (FcgammaRI and FcgammaRII) inhibited 70% and 55%, respectively, of the LDL-IC-induced secretion of MMP-1. Finally, our data showed that both PD98059, an inhibitor of the mitogen-activated protein kinase pathway, and Ro-31-2880, an inhibitor of protein kinase C, inhibited LDL-IC-stimulated MMP-1 secretion in a dose-dependent manner, with 96% and 95% inhibition, respectively, at the respective doses of 50 micromol/L and 80 nmol/L. In conclusion, this study demonstrated for the first time that LDL-ICs induce macrophage MMP-1 secretion by cocross-linking FcgammaRI and FcgammaRII and triggering a protein kinase C-dependent mitogen-activated protein kinase pathway. These results suggest that LDL-ICs and other ICs localized in atherosclerotic plaques may be potent stimulators for macrophage MMP-1 expression and may contribute to plaque rupture and acute coronary events.
authors: Division of Endocrinology, Diabetes, and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC 29403, USA. huangyan@musc.edu
authors: Y
authors: Y
authors: Huang
authors: A J
authors: AJ
authors: Fleming
authors: S
authors: S
authors: Wu
authors: G
authors: G
authors: Virella
authors: M F
authors: MF
authors: Lopes-Virella
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000936:Antigen-Antibody Complex / Q000276:immunology* / Q000494:pharmacology; D015703:Antigens, CD / Q000276:immunology*; D001161:Arteriosclerosis / Q000201:enzymology / Q000276:immunology; D017364:Collagenases / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000494:pharmacology; D008077:Lipoproteins, LDL / Q000276:immunology* / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology*; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D017452:Receptors, IgG / Q000037:antagonists & inhibitors / Q000276:immunology*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D020298:U937 Cells
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D015703:Antigens, CD; D004791:Enzyme Inhibitors; C080568:Fc gamma receptor IIA; D005419:Flavonoids; D007074:Immunoglobulin G; D008077:Lipoproteins, LDL; D017452:Receptors, IgG; D019715:Tissue Inhibitor of Metalloproteinase-1; C048844:anti-IgG; C099252:oxidized low density lipoprotein; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D017364:Collagenases; D020781:Matrix Metalloproteinase 1; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one