title: Cholesterol Crystals Activate the Lectin Complement Pathway via Ficolin-2 and Mannose-Binding Lectin: Implications for the Progression of Atherosclerosis.
abstract: Cholesterol crystals (CC) play an essential role in the formation of atherosclerotic plaques. CC activate the classical and the alternative complement pathways, but the role of the lectin pathway is unknown. We hypothesized that the pattern recognition molecules (PRMs) from the lectin pathway bind CC and function as an upstream innate inflammatory signal in the pathophysiology of atherosclerosis. We investigated the binding of the PRMs mannose-binding lectin (MBL), ficolin-1, ficolin-2, and ficolin-3, the associated serine proteases, and complement activation products to CC in vitro using recombinant proteins, specific inhibitors, as well as deficient and normal sera. Additionally, we examined the deposition of ficolin-2 and MBL in human carotid plaques by immunohistochemistry and fluorescence microscopy. The results showed that the lectin pathway was activated on CC by binding of ficolin-2 and MBL in vitro, resulting in activation and deposition of complement activation products. MBL bound to CC in a calcium-dependent manner whereas ficolin-2 binding was calcium-independent. No binding was observed for ficolin-1 or ficolin-3. MBL and ficolin-2 were present in human carotid plaques, and binding of MBL to CC was confirmed in vivo by immunohistochemistry, showing localization of MBL around CC clefts. Moreover, we demonstrated that IgM, but not IgG, bound to CC in vitro and that C1q binding was facilitated by IgM. In conclusion, our study demonstrates that PRMs from the lectin pathway recognize CC and provides evidence for an important role for this pathway in the inflammatory response induced by CC in the pathophysiology of atherosclerosis.
authors.affiliation: Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen O, Denmark;
authors.forename: Katrine
authors.initials: K
authors.lastname: Pilely
authors.affiliation: Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen O, Denmark;
authors.forename: Anne
authors.initials: A
authors.lastname: Rosbjerg
authors.affiliation: Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen O, Denmark;
authors.forename: Ninette
authors.identifier: 0000-0003-0992-793X
authors.initials: N
authors.lastname: Genster
authors.affiliation: Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences, 1113 Budapest, Hungary;
authors.forename: Peter
authors.initials: P
authors.lastname: Gal
authors.affiliation: Department of Biochemistry, Eötvös Loránd University, 1117 Budapest, Hungary;
authors.forename: Gábor
authors.initials: G
authors.lastname: Pál
authors.affiliation: Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, 0424 Oslo, Norway; K.G. Jebsen Inflammation Research Center, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway;
authors.forename: Bente
authors.identifier: 0000-0002-6529-6485
authors.initials: B
authors.lastname: Halvorsen
authors.affiliation: Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, 0424 Oslo, Norway; Hospital for Rheumatic Diseases, 2609 Lillehammer, Norway;
authors.forename: Sverre
authors.initials: S
authors.lastname: Holm
authors.affiliation: Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, 0424 Oslo, Norway; K.G. Jebsen Inflammation Research Center, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway;
authors.forename: Pål
authors.initials: P
authors.lastname: Aukrust
authors.affiliation: Center of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway;
authors.forename: Siril Skaret
authors.identifier: 0000-0003-1369-6230
authors.initials: SS
authors.lastname: Bakke
authors.affiliation: Center of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway;
authors.forename: Bjørnar
authors.identifier: 0000-0001-8304-9974
authors.initials: B
authors.lastname: Sporsheim
authors.affiliation: Section for Children's and Women's Health, Department of Laboratory Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway;
authors.forename: Ingunn
authors.initials: I
authors.lastname: Nervik
authors.affiliation: Center of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway;
authors.forename: Nathalie
authors.initials: N
authors.lastname: Niyonzima
authors.affiliation: Department of Clinical Biochemistry, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen O, Denmark;
authors.forename: Emil D
authors.initials: ED
authors.lastname: Bartels
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Center for Experimental Therapeutics and Reperfusion Injury, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115;
authors.forename: Gregory L
authors.identifier: 0000-0002-4805-8119
authors.initials: GL
authors.lastname: Stahl
authors.affiliation: K.G. Jebsen Inflammation Research Center, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway; Department of Immunology, Oslo University Hospital Rikshospitalet, 0424 Oslo, Norway; Research Laboratory, Nordland Hospital, 8038 Bodø, Norway; and K.G. Jebsen Thrombosis Research and Expertise Center, University of Tromsø, 9019 Tromsø, Norway.
authors.forename: Tom Eirik
authors.initials: TE
authors.lastname: Mollnes
authors.affiliation: Center of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway;
authors.forename: Terje
authors.identifier: 0000-0003-0354-5068
authors.initials: T
authors.lastname: Espevik
authors.affiliation: Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen O, Denmark; garred@post5.tele.dk.
authors.forename: Peter
authors.identifier: 0000-0002-2876-8586
authors.initials: P
authors.lastname: Garred
mesh_terms: D050197:Atherosclerosis / Q000276:immunology* / Q000503:physiopathology*; D002118:Calcium / Q000378:metabolism; D016893:Carotid Stenosis / Q000276:immunology; D002784:Cholesterol / Q000737:chemistry / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D003167:Complement Activation; D003181:Complement C4 / Q000378:metabolism; D003460:Crystallization; D018450:Disease Progression; D005455:Fluorescent Antibody Technique; D006023:Glycoproteins / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism; D007075:Immunoglobulin M / Q000276:immunology / Q000378:metabolism; D007249:Inflammation; D037102:Lectins / Q000276:immunology / Q000378:metabolism*; D037601:Mannose-Binding Lectin / Q000276:immunology / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D051192:Receptors, Pattern Recognition / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D000097604:Ficolins
chemical_list: D002118:Calcium; D002784:Cholesterol; D003181:Complement C4; D006023:Glycoproteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D037102:Lectins; D037601:Mannose-Binding Lectin; D051192:Receptors, Pattern Recognition; D011994:Recombinant Proteins; D000097604:Ficolins; C109662:FCN3 protein, human