In vitro interactions of oxidatively modified LDL with type I, II, III, IV, and V collagen, laminin, fibronectin, and poly-D-lysine.
The accumulation of LDL in the arterial intima is considered a key event in atherogenesis. We investigated the binding of oxidized LDL (ox-LDL) to microtiter plates coated with type I or II collagen, laminin, fibronectin, or poly-D-lysine. Oxidation of LDL, 125I-LDL, or Eu(3+)-LDL was performed with CuCl2, varying the time of oxidation. Bound lipoprotein was assessed by counting radioactivity or fluorescence in the wells. Binding of highly ox-LDL in PBS followed the order: type I collagen > poly-D-lysine > type II collagen > laminin > fibronectin. Comparing various collagen types, the binding of ox-LDL followed the order: type I > type V and, type III > type IV > type II collagen. Binding of ox-LDL in PBS was dependent on an increase in negative charge of ox-LDL. Testing certain amino acids as competitors for binding of highly ox-LDL to type I collagen put lysine first, followed by arginine and histidine. On laminin, histidine competed most, followed by lysine and arginine. When studying the influence of Na+, K+, Ca2+, Mg2+ (equivalent to their concentrations in the interstitial fluid), native LDL, moderately ox-LDL, and highly ox-LDL showed the same affinity to type I collagen. However, a fivefold dilution of the buffer increased the affinity of moderately and highly ox-LDL 3.9- and 10-fold compared with native LDL. Application of the F(ab')2 from a monoclonal antibody to ox-LDL revealed a strong competition of the binding of highly ox-LDL to type II collagen (60%), laminin (35%), type I collagen (20%), and poly-D-lysine (15%), whereas the binding to fibronectin was not affected.
Greilberger
J
J
Institute for Medical Biochemistry, Medical School, Karl-Franzens Universität Graz, Austria.
Schmut
O
O
Jürgens
G
G
D000447:Aldehydes / Q000276:immunology / Q000494:pharmacology; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D000906:Antibodies / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D001667:Binding, Competitive; D002412:Cations / Q000378:metabolism; D002417:Cattle; D002864:Chromogranins / Q000276:immunology; D003094:Collagen / Q000145:classification / Q000378:metabolism*; D000939:Epitopes / Q000276:immunology; D005353:Fibronectins / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007700:Kinetics; D007797:Laminin / Q000378:metabolism*; D015227:Lipid Peroxidation; D008077:Lipoproteins, LDL / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D008315:Malondialdehyde / Q000276:immunology / Q000494:pharmacology; D051379:Mice; D011107:Polylysine / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D011863:Radioimmunoassay
D000447:Aldehydes; D000596:Amino Acids; D000906:Antibodies; D000911:Antibodies, Monoclonal; D002412:Cations; D002864:Chromogranins; D000939:Epitopes; D005353:Fibronectins; D007074:Immunoglobulin G; D007797:Laminin; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D011107:Polylysine; D008315:Malondialdehyde; D003094:Collagen; C027576:4-hydroxy-2-nonenal