Published online before print April 1, 2004, doi: 10.1161/01.ATV.0000127302.24266.40
© 2004 American Heart Association, Inc.
Atherosclerosis and Lipoproteins |
Lack of Complement Factor C3, but Not Factor B, Increases Hyperlipidemia and Atherosclerosis in Apolipoprotein E–/– Low-Density Lipoprotein Receptor–/– Mice
From the Department of Medical Biochemistry (L.P., M.P.), Wallenberg Laboratory for Cardiovascular Research (J.B.), and Research Center for Endocrinology and Metabolism (V.W.), The Sahlgrenska Academy at Göteborg University, Göteborg; and the Center for Molecular Medicine (A.-K.L.R., G.K.H.), Karolinska Institute, Stockholm, Sweden
Correspondence to Dr Marcela Pekna, Department of Medical Biochemistry, Göteborg University Box 440 S-405 30, Göteborg, Sweden. E-mail Marcela.Pekna{at}medkem.gu.se
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionConclusionReferences |
|---|
Objective— To investigate the effect of complement deficiency on atherogenesis and lipidemia, we used mice deficient in the third complement component (C3–/–) or factor B (FB–/–).
Methods and Results— Complement-deficient mice were crossed with mice deficient in both apolipoprotein E and the low-density lipoprotein receptor (Apoe–/– LDLR–/–). The percent lesion area in the aorta at 16 weeks, determined by en face analysis, was 84% higher in C3–/– mice than in controls (11.8%±0.4% versus 6.4%±0.8%, mean±SEM, P<0.00005). The C3–/– mice also had 58% higher serum triglyceride levels (P<0.05) and a more proatherogenic lipoprotein profile, with significantly more low-density lipoprotein cholesterol and very-low-density lipoprotein triglycerides than control mice. The C3–/– mice weighed 13% less (P<0.01) and had a lower body fat content (3.5%±1.0% versus 13.1%±3.0%, P<0.01). There were no differences between FB–/– mice and controls.
Conclusions— Complement activation by the classical or lectin pathway exerts atheroprotective effects, possibly through the regulation of lipid metabolism.
Deficiency in C3, but not in factor B, leads to more extensive atherosclerotic lesions, increased hyperlipidemia, and reduced body fat in Apoe–/– LDLR–/– mice. Complement activation by the classical or lectin pathway exerts atheroprotective effects, possibly through the regulation of lipid metabolism.
Key Words: atherosclerosis • complement • C3 • factor B • hyperlipidemia
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionReferences |
|---|
The complement system plays an essential role in the humoral immune response. Soluble complement components are present in the blood in precursor forms and need to be activated to fulfill their specific physiological roles. Activated complement has diverse functions, including the initiation of inflammation, recruitment of leukocytes, clearance of immune complexes, neutralization of pathogens, regulation of antibody responses, and disruption of cell membranes. The complement cascade can be activated by 3 pathways. The classical activation pathway depends on assembly of complement factors at sites of antigen-antibody complexes. The lectin pathway is initiated by mannan-binding lectin bound to pathogen surfaces. Activation of the alternative pathway is triggered by a variety of pathogen surfaces and requires the interaction of third complement component (C3), factor B (FB), and factor D. Regardless of the pathway, activation leads to the cleavage of C3. This generates the smaller, proinflammatory C3a fragment and the larger C3b fragment. C3b can act as an opsonin and triggers the terminal part of the cascade, which culminates in the assembly of the terminal complement complex (TCC) on the target surface.
C3-derived peptides have been implicated in the regulation of lipid metabolism. C3a and C3ades-Arg, a peptide formed when the C-terminal arginine is removed from C3a by carboxypeptidase N, can act as acylation-stimulating protein (ASP).1 ASP has been implicated in adipose tissue function and maintenance of metabolic homeostasis.2 ASP and C3a increase fat storage in adipocytes through increased triglyceride synthesis3–5 and decreased intracellular lipolysis.5 Mice that are deficient in C3, and therefore unable to synthesize ASP, have delayed triglyceride clearance,6–8 which can be normalized by administration of ASP.7,9,10 However, Wetsel et al did not detect any impaired ability of C3–/– mice to clear triglycerides and free fatty acids from the circulation after an oral fat load.11 FB–/– mice are viable and fertile and have no overall abnormalities of the immune system.12,13 The effect of FB deficiency on adipose tissue and blood lipid profiles has thus far not been studied.
Atherosclerosis is characterized by an inflammatory response to the accumulation of subendothelial lipids, and there is evidence that the activated complement system is involved in atheroma formation.14 Complement components and activation products have been identified in the walls of diseased vessels,15–18 and mRNAs of complement components are expressed in atherosclerotic plaques. However, the role of complement inhibitors is more controversial.19,20 The degree of TCC deposition correlates with the severity of arterial damage.21,22 In rabbits, TCC and lipid colocalize in the aortic tunica intima.23 Similarly, in human lesions, TCC colocalizes with enzymatically modified lipoproteins.24 Lipoprotein particles in vitro as well as modified lipoproteins are also potent activators of complement.25,26 The severity of cholesterol-induced atherosclerosis is reduced in C6-deficient rabbits.27,28 In apolipoprotein E-deficient (Apoe–/–) mice, the absence of C5 does not affect atheroma formation,29 whereas aortic lipid-positive lesional size is reported to be greater in C3–/– low-density lipoprotein receptor-deficient (LDLR–/–) mice than in controls.30
To assess the role of the early components of the complement system in the pathogenesis of atherosclerosis and the regulation of plasma lipids, we crossed Apoe–/– LDLR–/– mice31 with C3–/–32 or FB–/– mice.12 C3–/– mice cannot activate the complement cascade beyond the formation of the C3-convertase of the classical/lectin pathway, and FB–/– mice are unable to activate the alternative pathway. The use of these 2 complement-deficient strains enabled us to assess the relative roles of these activation pathways.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionReferences |
|---|
Mice
To generate a complement-deficient, atherosclerosis-prone mouse model, we crossed C3–/–32 and FB–/– mice12 with Apoe–/– LDLR–/– mice.31 Complement-deficient males from the mating of C3+/– Apoe–/– LDLR–/– or FB+/–Apoe–/– LDLR–/– parents were compared with complement-sufficient Apoe–/– LDLR–/– siblings to minimize the effect of other genes on the mixed genetic background (C57BL/6J/129Ola). The mice were fed normal chow and analyzed at 16 or 26 weeks of age. The study was approved by the ethics committee at Göteborg University.
Processing and Analysis of the Aorta
The aortic root was processed and quantified as described.33 Sections were obtained 100, 200, 300, and 400 µm from the origin of the aortic valve cusps and stained with Oil Red O (Sigma-Aldrich, St. Louis, Mo). The aorta was prepared and analyzed en face as described.34 In brief, the aortas were pinned on wax plates and stained with Sudan IV. The extent of atherosclerosis was expressed as the percentage of the aortic surface covered by lesions. The results from control Apoe–/– LDLR–/– mice fed normal chow were comparable with data published for Apoe–/– and LDLR–/– mice fed a high-cholesterol diet.30,33
Serum Lipid Analyses
Blood for lipid analyses was collected before perfusion of the animals and allowed to clot, and the serum was stored at –20°C. Cholesterol and triglycerides were analyzed with a Konelab 30 automated analyzer (Thermo Electron Clinical Chemistry & Automation Systems) using the reagents triglycerides 981786 and cholesterol 981773, as recommended by the manufacturer. The lipid distribution in plasma lipoprotein fractions was assessed by fast-performance liquid chromatography gel filtration with a Superose 6 HR 10/30 column (Pharmacia, Uppsala, Sweden).35
Postprandial Triglyceride Clearance
Postprandial triglyceride clearance was measured as described.7 Blood samples were collected before and 1, 2, 3, 4, and 6 hours after oral administration of olive oil.
Body Fat Measurement
Body fat content was measured in vivo by dual-energy x-ray absorptiometry (DXA).36
Serum Anti-LDL Antibody Measurements
Specific antibodies to malondialdehyde (MDA)-modified low-density lipoprotein (LDL) were quantified by enzyme-linked immunosorbent assay.37
Histological Evaluation and Immunohistochemistry
Aortic root sections were stained with hematoxylin and erythrosine or Masson trichrome (Bio-Optica, Milan, Italy) to identify foam cells, fibrosis, cholesterol clefts, acellular areas, and fibrous cap in atherosclerotic plaques. For immunohistochemistry, sections were fixed in acetone, incubated with 1% bovine serum albumin in phosphate-buffered saline-Tween, and stained with MOMA-2 (Serotec, Oxford, UK) and 
-smooth muscle actin (EPOS; Dako A/S, Glostrup, Denmark) antibodies. The MOMA-2 antibody was detected by biotin-conjugated rabbit antiserum against rat immunoglobulins (Dako A/S) followed by ABC Vectastain Elite kit (Vector Laboratories, Burlingame, Calif) and visualized with 3, 3'-diaminobenzidine tetrahydrochloride (Sigma).
Statistical Analysis
The results are presented as mean±SEM. The data were analyzed by unpaired t test. Repeated-measures analysis of variance was used to analyze the postprandial triglyceride clearance data. Differences were considered statistically significant at P<0.05.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionReferences |
|---|
C3 Deficiency Increases Lesion Size at 16 Weeks of Age
Lesion size increased with age in all groups examined. All mice had advanced lesions composed of foam cells and abundant extracellular lipid at 16 weeks and fully developed atheromas with lipid-rich core regions covered by fibrous caps at 26 weeks. En face analysis of aortas at 16 weeks (Figure 1A and 1C) showed that the lesions were 84% larger in C3–/– than in complement-sufficient mice (11.8%±0.4% versus 6.4%±0.8% of surface area, P<0.00005). At 26 weeks, however, the lesions were of similar size in the 2 groups (Figure 2A). There were no differences in lesion size between FB–/– mice and controls at any time point (Figure 2B). In serial sections of the aortic root, the extent of atherosclerosis did not significantly differ between complement-deficient mice and control Apoe–/– LDLR–/– mice (not shown).
|
|
Atherosclerotic Lesions Are Qualitatively Similar in C3–/– and Control Mice
Morphological examination of aortic root sections at 16 weeks revealed lesions in all mice, ranging from fatty streaks composed of foam cells to advanced fibrofatty lesions covered by fibrous cap. At 26 weeks, the lesions often covered the whole inner circumference of the vessel, and all were exclusively of the fibroatheromatous type, the majority with large acellular areas, a fibrous cap of varying thickness, and extensive necrosis. No difference in plaque progression was noted between groups. As shown by MOMA-2 staining, macrophages were the predominant cell type in all lesions, although lesions in the older mice were less cellular. The extent and distribution of MOMA-2 staining were similar in complement-deficient mice and controls. Fibrous caps, visualized by -smooth muscle actin immunostaining, were observed in all sections analyzed, with no difference between the experimental groups (Figure I, available online at http://atvb.ahajournals.org).
C3 Deficiency Increases Serum Triglycerides and Alters Plasma Lipoprotein Profiles
In C3–/– mice, serum triglyceride levels were 58% higher than in controls at 16 weeks (6.8±0.9 versus 4.3±0.4 mmol/L, P<0.05) and 79% higher at 26 weeks (8.4±1.3 versus 4.4±0.6 mmol/L, P<0.05) (Figure 3A). C3 deficiency did not affect serum cholesterol levels at any age (Figure 3B). Serum cholesterol and triglyceride levels were similar in FB–/– and control mice (Figure 3C and 3D). Superose 6 chromatography of pooled plasma showed a more proatherogenic lipoprotein profile in C3–/– mice, with significantly more LDL cholesterol and very-low-density lipoprotein (VLDL) triglycerides than controls at both 16 and 26 weeks (Figure 4).
|
|
C3–/– Mice Have Normal Postprandial Triglyceride Clearance
Next, we determined if the increased serum lipid levels of the C3–/– mice could be explained by an aberrant postprandial lipid clearance. No differences in serum triglyceride levels were observed after an oral fat load in 21-week-old C3–/– (n=4) and control mice (n=5) (not shown).
C3 Deficiency Reduces Body Weight and Body Fat
Compared with controls, C3–/– mice weighed 13% less at 16 weeks (34.2±0.96 versus 38.8±1.29 g, n=17/group, P<0.01) and 22% less at 26 weeks (34.7±1.12 g, n=10, versus 42.3±1.93 g, n=11, P<0.005). There were no differences in body weight between the FB–/– and control mice at either time point. As shown by DXA analysis of body composition, C3–/– mice had approximately two-thirds less body fat than controls at 16 weeks (3.5%±1.0% versus 13.1%±3.0%, P<0.01) and 26 weeks (2.8%±0.7% versus 9.3±1.9%, P<0.01) (Figure 5).
|
C3 Deficiency Does Not Alter Anti-MDA–Modified-LDL Antibody Titers
To determine if the effect of complement on atherogenesis could result from changes in B-cell-associated protective immunity,38 we assessed the immunoglobulin M (IgM) and immunoglobulin G (IgG) isotypes of autoantibodies against MDA-modified LDL. There were no differences in anti-MDA-LDL IgM or IgG titers between C3–/– mice and controls (not shown).
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionReferences |
|---|
Complement activation has been suggested to contribute to the progression of atherosclerotic lesions, and complement-derived ASP has been implicated in the regulation of lipid metabolism. To address the relative roles of the classical and lectin pathways versus the alternative pathway of complement activation in these processes, we studied C3–/– and FB–/– mice. Remarkably, the aortic lesions were 84% larger in C3–/– mice than in complement-sufficient mice at 16 weeks of age. This finding is consistent with a recent report showing that C3 deficiency increased lipid-positive lesional size and impaired lesion maturation beyond the foam cell stage in 15-week-old LDLR–/– mice.30 Because serum lipoprotein/cholesterol profiles were not changed, the authors concluded that local effects of complement lead to lesion differences.
In our study, histopathological and immunohistochemical analyses of the aortic root showed no qualitative differences in lesion morphology between C3–/– and control mice. However, we cannot exclude that the C3 deficiency may have resulted in morphological differences such as reduced collagen and smooth muscle cell content in the lesions distal to the aortic root as reported for the C3–/– LDLR–/– mice.30 In addition, the strong atherogenic drive in the Apoe–/– LDLR–/– mice might have masked a milder anti-atherogenic effect of the complement system in the vascular wall and might also explain why C3–/– and control mice had lesions of similar size at 26 weeks. Given the possible role of antibodies in atheroprotective immunity,33,38–40 we analyzed sera from C3–/– and control mice for antibodies against MDA-LDL. No differences in antibody levels were detected, indicating that the increased atherosclerosis in C3–/– Apoe–/– LDLR–/– mice is not likely a result of impairments in B-cell-associated protective immunity or protective antibody production.
C3–/– mice also had a more atherogenic plasma lipoprotein profile than controls, with elevated serum triglyceride levels, increased VLDL triglycerides, and increased LDL cholesterol. In addition, the C3–/– mice weighed less and had a lower body fat mass. The latter findings are in line with recent reports showing that C3–/– mice had reduced body weight and fat mass and were resistant to weight gain on a high-fat diet, despite increased food intake.8,41 These phenotypic abnormalities may reflect reduced triglyceride synthesis by adipocytes because of the absence of C3-derived ASP, as proposed by Sniderman et al.42 Thus, the absence of ASP leads to a more atherogenic lipoprotein profile and increased atherosclerosis. Cianflone et al2 suggested that discrepancies in plasma lipid levels and triglyceride clearance in C3–/– mice in different reports6–8,11 could be explained by the influence of genetic background, resulting in differences in insulin sensitivity, lipoprotein lipase activity, or triglyceride synthesis by adipose tissue.
In contrast to the results in C3–/– mice, the extent of atherosclerosis, serum triglyceride levels, and body weight were not significantly different in FB–/– Apoe–/– LDLR–/– mice and controls. Because C3, FB, and factor D are produced in adipose tissue, ASP is believed to be generated by the alternative pathway of complement activation. In support of this possibility, there is no evidence that adipocytes produce C2, an essential component of the classical and lectin pathways.43,44 Although FB–/– mice have normal C3 levels, they cannot generate ASP through proteolytic cleavage mediated by FB and factor D. Our findings suggest that the alternative pathway is not required for C3-mediated control of energy storage and energy use and that ASP is generated by other mechanisms, such as activation of the classical and/or lectin pathway locally in adipose tissue or in the circulation. Interestingly, genes encoding proteins of the classical pathway are expressed in human adipose tissue.45
An alternative explanation for the phenotype of the C3–/– mice is the absence of uncleaved C3. One possibility worth exploring is the capacity of C3(H2O) to bind to the C3a/ASP receptor C5L246 and to exhibit the functions ascribed to ASP. C3(H2O)—the product of spontaneous hydrolysis of the internal thioester bond of the native C3 molecule—is conformationally and functionally similar to C3b. It can bind FB and form the C3 convertase of the alternative pathway. However, it still contains the C3a fragment47–49 and therefore could, theoretically, act like ASP.
En face assessment of the whole aorta revealed a significant difference in percent lesion area between C3–/– and control mice at 16 weeks of age that were not seen by analysis of aortic root sections. Babaev et al also reported a loss of correlation between lesion areas determined by these two methods when lesions in the proximal aorta became complicated.50 Thus, for detecting effects on disease development, en face analysis of the percent lesion area appears to be a more sensitive method than measuring plaque area in sections from the aortic root, at least in the Apoe–/– LDLR–/– model.
|
Conclusion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionReferences |
|---|
In conclusion, deficiency in C3, but not FB, leads to increased hyperlipidemia, a more atherogenic lipoprotein profile, more extensive atherosclerotic lesions, and reduced body weight and body fat in Apoe–/– LDLR–/– mice. These results suggest that complement activation via the classical or lectin pathway exerts atheroprotective effects, possibly through the regulation of lipid metabolism. However, the exact mechanisms remain unclear and further investigation is warranted.
|
Acknowledgments |
|---|
Acknowledgments
The authors thank Kristina Skålén, Maria Garcia, Anna Berndtsson, Lisbeth Lindgren, and Ingrid Törnberg for technical help. The work was supported by grants from The Swedish Medical Research Council (Projects 13470 and 6816), King Gustaf V 80th Anniversary Foundation, The Swedish Heart-Lung Foundation, The Swedish Society of Medicine, The Swedish Society for Medical Research, and Sigurd and Elsa Golje’s Foundation.
|
Footnotes |
|---|
Consulting Editor for this article was Peter Libby, MD, Brigham and Women’s Hospital, Boston, Mass.
Received December 22, 2003; accepted March 22, 2004.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionReferences |
|---|
1. Baldo A, Sniderman AD, St-Luce S, Avramoglu RK, Maslowska M, Hoang B, Monge JC, Bell A, Mulay S, Cianflone K. The adipsin-acylation stimulating protein system and regulation of intracellular triglyceride synthesis. J Clin Invest. 1993; 92: 1543–1547.
2. Cianflone K, Xia Z, Chen LY. Critical review of acylation-stimulating protein physiology in humans and rodents. Biochim Biophys Acta. 2003; 1609: 127–143.[Medline] [Order article via Infotrieve]
3. Murray I, Parker RA, Kirchgessner TG, Tran J, Zhang ZJ, Westerlund J, Cianflone K. Functional bioactive recombinant acylation stimulating protein is distinct from C3a anaphylatoxin. J Lipid Res. 1997; 38: 2492–2501.[Abstract]
4. Cianflone K, Roncari DA, Maslowska M, Baldo A, Forden J, Sniderman AD. Adipsin/acylation stimulating protein system in human adipocytes: regulation of triacylglycerol synthesis. Biochemistry. 1994; 33: 9489–9495.[CrossRef][Medline] [Order article via Infotrieve]
5. Van Harmelen V, Reynisdottir S, Cianflone K, Degerman E, Hoffstedt J, Nilsell K, Sniderman A, Arner P. Mechanisms involved in the regulation of free fatty acid release from isolated human fat cells by acylation-stimulating protein and insulin. J Biol Chem. 1999; 274: 18243–18251.
6. Murray I, Sniderman AD, Havel PJ, Cianflone K. Acylation stimulating protein (ASP) deficiency alters postprandial and adipose tissue metabolism in male mice. J Biol Chem. 1999; 274: 36219–36225.
7. Murray I, Sniderman AD, Cianflone K. Mice lacking acylation stimulating protein (ASP) have delayed postprandial triglyceride clearance. J Lipid Res. 1999; 40: 1671–1676.
8. Xia Z, Sniderman AD, Cianflone K. Acylation-stimulating protein (ASP) deficiency induces obesity resistance and increased energy expenditure in ob/ob mice. J Biol Chem. 2002; 277: 45874–45879.
9. Murray I, Sniderman AD, Cianflone K. Enhanced triglyceride clearance with intraperitoneal human acetylation stimulating protein (ASP) in C57BL/6 mice. Am J Physiol Endocrinol Metab. 1999; 277: E474–E480.
10. Saleh J, Blevins JE, Havel PJ, Barrett JA, Gietzen DW, Cianflone K. Acylation stimulating protein (ASP) acute effects on postprandial lipemia and food intake in rodents. Int J Obes Relat Metab Disord. 2001; 25: 705–713.[CrossRef][Medline] [Order article via Infotrieve]
11. Wetsel RA, Kildsgaard J, Zsigmond E, Liao W, Chan L. Genetic deficiency of acylation stimulating protein (ASP(C3ades-Arg)) does not cause hyperapobetalipoproteinemia in mice. J Biol Chem. 1999; 274: 19429–19433.
12. Pekna M, Hietala MA, Landin A, Nilsson A-K, Lagerberg C, Betsholtz C, Pekny M. Mice deficient for complement factor B develop and reproduce normally. Scand J Immunol. 1998; 47: 375–380.[CrossRef][Medline] [Order article via Infotrieve]
13. Matsumoto M, Fukuda W, Circolo A, Goellner J, Strauss-Schoenberger J, Wang X, Fujita S, Hidvegi T, Chaplin DD, Colten HR. Abrogation of the alternative complement pathway by targeted deletion of murine factor B. Proc Natl Acad Sci U S A. 1997; 94: 8720–8725.
14. Niculescu F, Rus H. Complement activation and atherosclerosis. Mol Immunol. 1999; 36: 949–955.[CrossRef][Medline] [Order article via Infotrieve]
15. Pang ASD, Katz A, Minta JO. C3 deposition in cholesterol-induced atherosclerosis in rabbits: A possible etiologic role for complement in atherogenesis. J Immunol. 1979; 123: 1117–1122.
16. Hansson GK, Holm J, Kral IG. Accumulation of IgG and complement factor C3 in human arterial endothelium and atherosclerotic lesions. Acta Pathol Microbiol Immunol Scand Sect A. 1984; 92: 429–435.[Medline] [Order article via Infotrieve]
17. Vlaicu R, Rus HG, Niculescu F, Cristea A. Immunoglobulins and complement components in human aortic intima. Atherosclerosis. 1985; 55: 35–50.[CrossRef][Medline] [Order article via Infotrieve]
18. Seifert PS, Messner M, Roth I, Bhakdi S. Analysis of complement C3 activation products in human atherosclerotic lesions. Atherosclerosis. 1991; 91: 155–162.[CrossRef][Medline] [Order article via Infotrieve]
19. Yasojima K, Schwab C, McGeer EG, McGeer PL. Complement components, but not complement inhibitors, are upregulated in atherosclerotic plaques. Arterioscler Thromb Vasc Biol. 2001; 21: 1214–1219.
20. Seifert PS, Hansson GK. Complement receptors and regulatory proteins in human atherosclerotic lesions. Arteriosclerosis. 1989; 9: 802–811.
21. Niculescu F, Rus HG, Vlaicu R. Immunohistochemical localization of C5b-9, S-protein, C3d and apolipoprotein B in human arterial tissues with atherosclerosis. Atherosclerosis. 1987; 65: 1–11.[CrossRef][Medline] [Order article via Infotrieve]
22. Seifert PS, Kazatchkine MD. The complement system in atherosclerosis. Atherosclerosis. 1988; 73: 91–104.[CrossRef][Medline] [Order article via Infotrieve]
23. Seifert PS, Hugo F, Hansson GK, Bhakdi S. Prelesional complement activation in experimental atherosclerosis. Terminal C5b-9 complement deposition coincides with cholesterol accumulation in the aortic intima of hypercholesterolemic rabbits. Lab Invest. 1989; 60: 747–754.[Medline] [Order article via Infotrieve]
24. Torzewski M, Klouche M, Hock J, Messner M, Dorweiler B, Torzewski J, Gabbert HE, Bhakdi S. Immunohistochemical demonstration of enzymatically modified human LDL and its colocalization with the terminal complement complex in the early atherosclerotic lesion. Arterioscler Thromb Vasc Biol. 1998; 18: 369–378.
25. Bhakdi S, Torzewski M, Klouche M, Hemmes M. Complement and atherogenesis: binding of CRP to degraded, nonoxidized LDL enhances complement activation. Arterioscler Thromb Vasc Biol. 1999; 19: 2348–2354.
26. Seifert PS, Hugo F, Tranum-Jensen J, Zahringer U, Muhly M, Bhakdi S. Isolation and characterization of a complement-activating lipid extracted from human atherosclerotic lesions. J Exp Med. 1990; 172: 547–557.
27. Geertinger P, Sorensen H. On the reduced atherogenic effect of cholesterol feeding in rabbits with congenital complement (C6) deficiency. Artery. 1977; 1: 177–184.
28. Schmiedt W, Kinscherf R, Deigner H-P, Kamencic H, Nauen O, Kilo J, Oeler H, Metz J, Bhakdi S. Complement C6 deficiency protects against diet-induced atherosclerosis in rabbits. Arterioscler Thromb Vasc Biol. 1998; 18: 1790–1795.
29. Patel S, Thelander EM, Hernandez M, Montenegro J, Hassing H, Burton C, Mundt S, Hermanowski-Vosatka A, Wright SD, Chao Y-S, Detmers P. ApoE–/– mice develop atherosclerosis in the absence of complement component C5. Biochem Biophys Res Commun. 2001; 286: 164–170.[CrossRef][Medline] [Order article via Infotrieve]
30. Buono C, Come CE, Witztum JL, Maguire GF, Conelly PW, Carroll MC, Lichtman AH. Influence of C3 deficiency on atherosclerosis. Circulation. 2002; 105: 3025–3031.
31. Witting PK, Pettersson K, Ostlund-Lindqvist AM, Westerlund C, Eriksson AW, Stocker R. Inhibition by a coantioxidant of aortic lipoprotein lipid peroxidation and atherosclerosis in apolipoprotein E and low density lipoprotein receptor gene double knockout mice. FASEB J. 1999; 13: 667–675.
32. Pekna M, Hietala MA, Rosklint T, Betsholtz C, Pekny M. Targeted disruption of the murine gene coding for the third complement component (C3). Scand. J Immunol. 1998; 47: 25–29.[CrossRef][Medline] [Order article via Infotrieve]
33. Nicoletti A, Kaveri S, Caligiuri G, Bariety J, Hansson G. Immunoglobulin treatment reduces atherosclerosis in apo E knockout mice. J Clin Invest. 1998; 102: 910–918.[Medline] [Order article via Infotrieve]
34. Tangirala RK, Rubin EM, Palinski W. Quantitation of atherosclerosis in murine models: correlation between lesions in the aortic origin and in the entire aorta, and differences in the extent of lesions between sexes in LDL receptor-deficient and apolipoprotein E-deficient mice. J Lipid Res. 1995; 36: 2320–2328.[Abstract]
35. Purcell-Huynh DA, Farese RV, Jr., Johnson DF, Flynn LM, Pierotti V, Newland DL, Linton MF, Sanan DA, Young SG. Transgenic mice expressing high levels of human apolipoprotein B develop severe atherosclerotic lesions in response to a high-fat diet. J Clin Invest. 1995; 95: 2246–2257.
36. Sjogren K, Wallenius K, Liu JL, Bohlooly YM, Pacini G, Svensson L, Tornell J, Isaksson OG, Ahren B, Jansson JO, Ohlsson C. Liver-derived IGF-I is of importance for normal carbohydrate and lipid metabolism. Diabetes. 2001; 50: 1539–1545.
37. Robertson AK, Rudling M, Zhou X, Gorelik L, Flavell RA, Hansson GK. Disruption of TGF-{beta} signaling in T cells accelerates atherosclerosis. J Clin Invest. 2003; 112: 1342–1350.[CrossRef][Medline] [Order article via Infotrieve]
38. Caligiuri G, Nicoletti A, Poirier B, Hansson GK. Protective immunity against atherosclerosis carried by B cells of hypercholesterolemic mice. J Clin Invest. 2002; 109: 721–724.[CrossRef][Medline] [Order article via Infotrieve]
39. Palinski W, Miller EJ, Witztum JL. Immunization of low density lipoprotein (LDL) receptor-deficient rabbits with homologous malondialdehyde-modified LDL reduces atherogenesis. Proc Natl Acad Sci U S A. 1995; 92: 821–825.
40. Zhou X, Caligiuri G, Hamsten A, Lefvert AK, Hansson G. LDL immunization induces T-cell-dependent antibody formation and protection against atherosclerosis. Arterioscler Thromb Vasc Biol. 2001; 21: 108–114.
41. Murray I, Havel P, Sniderman AD, Cianflone K. Reduced body weight, adipose tissue, and leptin levels despite increased energy intake in female mice lacking acetylation-stimulating protein. Endocrinology. 2000; 141: 1041–1049.
42. Sniderman AD, Cianflone K, Arner P, Summers LK, Frayn KN. The adipocyte, fatty acid trapping, and atherogenesis. Arterioscler Thromb Vasc Biol. 1998; 18: 147–151.
43. Choy LN, Rosen BS, Spiegelman BM. Adipsin and an endogenous pathway of complement from adipose cells. J Biol Chem. 1992; 267: 12736–12741.
44. Choy LN, Spiegelman BM. Regulation of alternative pathway activation and C3a production by adipose cells. Obes Res. 1996; 4: 521–532.[Medline] [Order article via Infotrieve]
45. Gabrielsson BG, Johansson JM, Lonn M, Jernas M, Olbers T, Peltonen M, Larsson I, Lonn L, Sjostrom L, Carlsson B, Carlsson LM. High expression of complement components in omental adipose tissue in obese men. Obes Res. 2003; 11: 699–708.[Medline] [Order article via Infotrieve]
46. Kalant D, Cain SA, Maslowska M, Sniderman AD, Cianflone K, Monk PN. The chemoattractant receptor-like protein C5L2 binds the C3a des-Arg77/acylation-stimulating protein. J Biol Chem. 2003; 278: 11123–11129.
47. Pangburn MK, Muller-Eberhard HJ. Relation of a putative thiolester bond in C3 to activation of the alternative pathway and the binding of C3b to biological targets of complement. J Exp Med. 1980; 152: 1102–1114.
48. Pangburn MK, Schreiber RD, Muller-Eberhard HJ. Formation of the initial C3 convertase of the alternative complement pathway. Acquisition of C3b-like activities by spontaneous hydrolysis of the putative thiolester in native C3. J Exp Med. 1981; 154: 856–867.
49. Isenman DE, Kells DIC, Cooper NR, Muller-Eberhard HJ, Pangburn MK. Nucleophilic modification of human complement protein C3: correlation of conformational changes with acquisition of C3b-like functional properties. Biochemistry. 1981; 20: 4458–4467.[CrossRef][Medline] [Order article via Infotrieve]
50. Babaev VR, Patel MB, Semenkovich CF, Fazio S, Linton MF. Macrophage lipoprotein lipase promotes foam cell formation and atherosclerosis in low density lipoprotein receptor-deficient mice. J Biol Chem. 2000; 275: 26293–26299.
This article has been cited by other articles:
 |
|
 |
|
  V. W.Y. Leung, S. Yun, M. Botto, J. C. Mason, T. H. Malik, W. Song, D. Paixao-Cavalcante, M. C. Pickering, J. J. Boyle, and D. O. Haskard Decay-Accelerating Factor Suppresses Complement C3 Activation and Retards Atherosclerosis in Low-Density Lipoprotein Receptor-Deficient Mice Am. J. Pathol., October 1, 2009; 175(4): 1757 - 1767. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. J. Lewis, T. H. Malik, M. R. Ehrenstein, J. J. Boyle, M. Botto, and D. O. Haskard Immunoglobulin M Is Required for Protection Against Atherosclerosis in Low-Density Lipoprotein Receptor-Deficient Mice Circulation, August 4, 2009; 120(5): 417 - 426. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Matthijsen, M. P.J. de Winther, D. Kuipers, I. van der Made, C. Weber, M. V. Herias, M. J.J. Gijbels, and W. A. Buurman Macrophage-Specific Expression of Mannose-Binding Lectin Controls Atherosclerosis in Low-Density Lipoprotein Receptor-Deficient Mice Circulation, April 28, 2009; 119(16): 2188 - 2195. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Wu, W. Hu, A. Shahsafaei, W. Song, M. Dobarro, G. K. Sukhova, R. R. Bronson, G.-p. Shi, R. P. Rother, J. A. Halperin, et al. Complement Regulator CD59 Protects Against Atherosclerosis by Restricting the Formation of Complement Membrane Attack Complex Circ. Res., February 27, 2009; 104(4): 550 - 558. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Paglialunga, A. Fisette, Y. Yan, Y. Deshaies, J.-F. Brouillette, M. Pekna, and K. Cianflone Acylation-stimulating protein deficiency and altered adipose tissue in alternative complement pathway knockout mice Am J Physiol Endocrinol Metab, March 1, 2008; 294(3): E521 - E529. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Shagdarsuren, K. Bidzhekov, Y. Djalali-Talab, E. A. Liehn, M. Hristov, R. A. Matthijsen, W. A. Buurman, A. Zernecke, and C. Weber C1-Esterase Inhibitor Protects Against Neointima Formation After Arterial Injury in Atherosclerosis-Prone Mice Circulation, January 1, 2008; 117(1): 70 - 78. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Verdeguer, C. Castro, M. Kubicek, D. Pla, M. Vila-Caballer, A. Vinue, F. Civeira, M. Pocovi, J. J. Calvete, and V. Andres Complement regulation in murine and human hypercholesterolemia and role in the control of macrophage and smooth muscle cell proliferation Cardiovasc Res, November 1, 2007; 76(2): 340 - 350. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Paglialunga, P. Schrauwen, C. Roy, E. Moonen-Kornips, H. Lu, M. K C Hesselink, Y. Deshaies, D. Richard, and K. Cianflone Reduced adipose tissue triglyceride synthesis and increased muscle fatty acid oxidation in C5L2 knockout mice J. Endocrinol., August 1, 2007; 194(2): 293 - 304. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. K. Bhatia, S. Yun, V. Leung, D. C. Grimsditch, G. M. Benson, M. B. Botto, J. J. Boyle, and D. O. Haskard Complement C1q Reduces Early Atherosclerosis in Low-Density Lipoprotein Receptor-Deficient Mice Am. J. Pathol., January 1, 2007; 170(1): 416 - 426. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. K. Hansson Epidemiology Complements Immunology in the Heart Arterioscler Thromb Vasc Biol, October 1, 2006; 26(10): 2178 - 2180. [Full Text] [PDF]
|
|
|
|
|
|
M. Marcil, H. Vu, W. Cui, Z. Dastani, J. C. Engert, D. Gaudet, M. Castro-Cabezas, A. D. Sniderman, J. Genest Jr, and K. Cianflone Identification of a Novel C5L2 Variant (S323I) in a French Canadian Family With Familial Combined Hyperlipemia Arterioscler Thromb Vasc Biol, July 1, 2006; 26(7): 1619 - 1625. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. M Carter Inflammation, thrombosis and acute coronary syndromes Diabetes and Vascular Disease Research, October 1, 2005; 2(3): 113 - 121. [Abstract] [PDF]
|
|
|
|
 |
|
 J. Li, P. C. Pircher, I. G. Schulman, and S. K. Westin Regulation of Complement C3 Expression by the Bile Acid Receptor FXR J. Biol. Chem., March 4, 2005; 280(9): 7427 - 7434. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. S. Getz Thematic review series: The Immune System and Atherogenesis. Immune function in atherogenesis J. Lipid Res., January 1, 2005; 46(1): 1 - 10. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||