Skip to main content
NCBI home page
The Journal of Clinical Investigation logoLink to The Journal of Clinical Investigation
. 1998 Apr 15;101(8):1670–1677. doi: 10.1172/JCI119887

Phenotype-dependent differences in apolipoprotein E metabolism and in cholesterol homeostasis in human monocyte-derived macrophages.

P Cullen 1, A Cignarella 1, B Brennhausen 1, S Mohr 1, G Assmann 1, A von Eckardstein 1
PMCID: PMC508748  PMID: 9541497

Abstract

In this study, we investigated the impact of the common apoE polymorphism on apoE metabolism and cholesterol homeostasis in monocyte-derived macrophages isolated from E2/2, E3/3, and E4/4 subjects. Unloaded cells of all genotypes contained similar amounts of free cholesterol, cholesteryl ester, and apoE mRNA. E3/3 cells secreted 77 and 30% more apoE than E2/2 or E4/4 cells, respectively. Pulse-chase studies confirmed that the apoE secretion rate was greatest in E3/3 and least in E2/2 cells and showed that a portion of apoE2, but not apoE3 or apoE4, was degraded intracellularly. Surface binding of apoE was greatest in E4/4 cells, as revealed by heparinase treatment. On cholesterol loading with acetylated LDL, apoE mRNA levels and protein secretion rose most in E4/4 and least in E2/2 cells. Cholesterol and cholesteryl ester content, however, rose most in E2/2 and least in E3/3 cells. Incubations with 3H-cholesterol-labeled acetylated LDL revealed that E2/2 cells were most efficient at secreting cholesterol. The greatest reuptake of 3H-cholesterol-rich particles was from E4/4 macrophage- conditioned media. Thus, E2/2 macrophages, despite a low apoE secretion rate, are protected from cholesterol storage by apoE-mediated cholesterol efflux. In E3/3 macrophages, cholesterol accumulation is lessened by a high basal apoE secretion rate. E4/4 macrophages secrete the most apoE but lack effective net cholesterol efflux due to enhanced surface binding and reuptake of cholesterol-rich particles.

Full Text

The Full Text of this article is available as a PDF (208.9 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Basu S. K., Goldstein J. L., Anderson G. W., Brown M. S. Degradation of cationized low density lipoprotein and regulation of cholesterol metabolism in homozygous familial hypercholesterolemia fibroblasts. Proc Natl Acad Sci U S A. 1976 Sep;73(9):3178–3182. doi: 10.1073/pnas.73.9.3178. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bellosta S., Mahley R. W., Sanan D. A., Murata J., Newland D. L., Taylor J. M., Pitas R. E. Macrophage-specific expression of human apolipoprotein E reduces atherosclerosis in hypercholesterolemic apolipoprotein E-null mice. J Clin Invest. 1995 Nov;96(5):2170–2179. doi: 10.1172/JCI118271. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bickeböller H., Campion D., Brice A., Amouyel P., Hannequin D., Didierjean O., Penet C., Martin C., Pérez-Tur J., Michon A. Apolipoprotein E and Alzheimer disease: genotype-specific risks by age and sex. Am J Hum Genet. 1997 Feb;60(2):439–446. [PMC free article] [PubMed] [Google Scholar]
  4. Boerwinkle E., Visvikis S., Welsh D., Steinmetz J., Hanash S. M., Sing C. F. The use of measured genotype information in the analysis of quantitative phenotypes in man. II. The role of the apolipoprotein E polymorphism in determining levels, variability, and covariability of cholesterol, betalipoprotein, and triglycerides in a sample of unrelated individuals. Am J Med Genet. 1987 Jul;27(3):567–582. doi: 10.1002/ajmg.1320270310. [DOI] [PubMed] [Google Scholar]
  5. Boisvert W. A., Spangenberg J., Curtiss L. K. Treatment of severe hypercholesterolemia in apolipoprotein E-deficient mice by bone marrow transplantation. J Clin Invest. 1995 Aug;96(2):1118–1124. doi: 10.1172/JCI118098. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Brand K., Mackman N., Curtiss L. K. Interferon-gamma inhibits macrophage apolipoprotein E production by posttranslational mechanisms. J Clin Invest. 1993 May;91(5):2031–2039. doi: 10.1172/JCI116425. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Chomczynski P., Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987 Apr;162(1):156–159. doi: 10.1006/abio.1987.9999. [DOI] [PubMed] [Google Scholar]
  8. Corder E. H., Saunders A. M., Strittmatter W. J., Schmechel D. E., Gaskell P. C., Small G. W., Roses A. D., Haines J. L., Pericak-Vance M. A. Gene dose of apolipoprotein E type 4 allele and the risk of Alzheimer's disease in late onset families. Science. 1993 Aug 13;261(5123):921–923. doi: 10.1126/science.8346443. [DOI] [PubMed] [Google Scholar]
  9. Cullen P., Fobker M., Tegelkamp K., Meyer K., Kannenberg F., Cignarella A., Benninghoven A., Assmann G. An improved method for quantification of cholesterol and cholesteryl esters in human monocyte-derived macrophages by high performance liquid chromatography with identification of unassigned cholesteryl ester species by means of secondary ion mass spectrometry. J Lipid Res. 1997 Feb;38(2):401–409. [PubMed] [Google Scholar]
  10. Davignon J., Gregg R. E., Sing C. F. Apolipoprotein E polymorphism and atherosclerosis. Arteriosclerosis. 1988 Jan-Feb;8(1):1–21. doi: 10.1161/01.atv.8.1.1. [DOI] [PubMed] [Google Scholar]
  11. Deng J., Rudick V., Dory L. Lysosomal degradation and sorting of apolipoprotein E in macrophages. J Lipid Res. 1995 Oct;36(10):2129–2140. [PubMed] [Google Scholar]
  12. Ehnholm C., Lukka M., Kuusi T., Nikkilä E., Utermann G. Apolipoprotein E polymorphism in the Finnish population: gene frequencies and relation to lipoprotein concentrations. J Lipid Res. 1986 Mar;27(3):227–235. [PubMed] [Google Scholar]
  13. Grassi G., Zentilin L., Tafuro S., Diviacco S., Ventura A., Falaschi A., Giacca M. A rapid procedure for the quantitation of low abundance RNAs by competitive reverse transcription-polymerase chain reaction. Nucleic Acids Res. 1994 Oct 25;22(21):4547–4549. doi: 10.1093/nar/22.21.4547. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Havekes L. M., de Knijff P., Beisiegel U., Havinga J., Smit M., Klasen E. A rapid micromethod for apolipoprotein E phenotyping directly in serum. J Lipid Res. 1987 Apr;28(4):455–463. [PubMed] [Google Scholar]
  15. Huang Y., von Eckardstein A., Wu S., Assmann G. Effects of the apolipoprotein E polymorphism on uptake and transfer of cell-derived cholesterol in plasma. J Clin Invest. 1995 Dec;96(6):2693–2701. doi: 10.1172/JCI118336. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Huang Y., von Eckardstein A., Wu S., Maeda N., Assmann G. A plasma lipoprotein containing only apolipoprotein E and with gamma mobility on electrophoresis releases cholesterol from cells. Proc Natl Acad Sci U S A. 1994 Mar 1;91(5):1834–1838. doi: 10.1073/pnas.91.5.1834. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Ji Z. S., Fazio S., Lee Y. L., Mahley R. W. Secretion-capture role for apolipoprotein E in remnant lipoprotein metabolism involving cell surface heparan sulfate proteoglycans. J Biol Chem. 1994 Jan 28;269(4):2764–2772. [PubMed] [Google Scholar]
  18. Kruth H. S., Skarlatos S. I., Gaynor P. M., Gamble W. Production of cholesterol-enriched nascent high density lipoproteins by human monocyte-derived macrophages is a mechanism that contributes to macrophage cholesterol efflux. J Biol Chem. 1994 Sep 30;269(39):24511–24518. [PubMed] [Google Scholar]
  19. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  20. Linton M. F., Atkinson J. B., Fazio S. Prevention of atherosclerosis in apolipoprotein E-deficient mice by bone marrow transplantation. Science. 1995 Feb 17;267(5200):1034–1037. doi: 10.1126/science.7863332. [DOI] [PubMed] [Google Scholar]
  21. Lucas M., Mazzone T. Cell surface proteoglycans modulate net synthesis and secretion of macrophage apolipoprotein E. J Biol Chem. 1996 Jun 7;271(23):13454–13460. doi: 10.1074/jbc.271.23.13454. [DOI] [PubMed] [Google Scholar]
  22. Mahley R. W. Apolipoprotein E: cholesterol transport protein with expanding role in cell biology. Science. 1988 Apr 29;240(4852):622–630. doi: 10.1126/science.3283935. [DOI] [PubMed] [Google Scholar]
  23. Mazzone T. Apolipoprotein E secretion by macrophages: its potential physiological functions. Curr Opin Lipidol. 1996 Oct;7(5):303–307. doi: 10.1097/00041433-199610000-00008. [DOI] [PubMed] [Google Scholar]
  24. Mazzone T., Basheeruddin K., Poulos C. Regulation of macrophage apolipoprotein E gene expression by cholesterol. J Lipid Res. 1989 Jul;30(7):1055–1064. [PubMed] [Google Scholar]
  25. Mazzone T., Gump H., Diller P., Getz G. S. Macrophage free cholesterol content regulates apolipoprotein E synthesis. J Biol Chem. 1987 Aug 25;262(24):11657–11662. [PubMed] [Google Scholar]
  26. Mazzone T., Pustelnikas L., Reardon C. A. Post-translational regulation of macrophage apoprotein E production. J Biol Chem. 1992 Jan 15;267(2):1081–1087. [PubMed] [Google Scholar]
  27. Mazzone T., Reardon C. Expression of heterologous human apolipoprotein E by J774 macrophages enhances cholesterol efflux to HDL3. J Lipid Res. 1994 Aug;35(8):1345–1353. [PubMed] [Google Scholar]
  28. O'Brien K. D., Deeb S. S., Ferguson M., McDonald T. O., Allen M. D., Alpers C. E., Chait A. Apolipoprotein E localization in human coronary atherosclerotic plaques by in situ hybridization and immunohistochemistry and comparison with lipoprotein lipase. Am J Pathol. 1994 Mar;144(3):538–548. [PMC free article] [PubMed] [Google Scholar]
  29. Oram J. F., Yokoyama S. Apolipoprotein-mediated removal of cellular cholesterol and phospholipids. J Lipid Res. 1996 Dec;37(12):2473–2491. [PubMed] [Google Scholar]
  30. Ordovas J. M., Litwack-Klein L., Wilson P. W., Schaefer M. M., Schaefer E. J. Apolipoprotein E isoform phenotyping methodology and population frequency with identification of apoE1 and apoE5 isoforms. J Lipid Res. 1987 Apr;28(4):371–380. [PubMed] [Google Scholar]
  31. Pieters M. N., Esbach S., Schouten D., Brouwer A., Knook D. L., Van Berkel T. J. Cholesteryl esters from oxidized low-density lipoproteins are in vivo rapidly hydrolyzed in rat Kupffer cells and transported to liver parenchymal cells and bile. Hepatology. 1994 Jun;19(6):1459–1467. [PubMed] [Google Scholar]
  32. Pitas R. E., Boyles J. K., Lee S. H., Foss D., Mahley R. W. Astrocytes synthesize apolipoprotein E and metabolize apolipoprotein E-containing lipoproteins. Biochim Biophys Acta. 1987 Jan 13;917(1):148–161. doi: 10.1016/0005-2760(87)90295-5. [DOI] [PubMed] [Google Scholar]
  33. Rosenfeld M. E., Butler S., Ord V. A., Lipton B. A., Dyer C. A., Curtiss L. K., Palinski W., Witztum J. L. Abundant expression of apoprotein E by macrophages in human and rabbit atherosclerotic lesions. Arterioscler Thromb. 1993 Sep;13(9):1382–1389. doi: 10.1161/01.atv.13.9.1382. [DOI] [PubMed] [Google Scholar]
  34. Schmitz G., Assmann G., Bowyer D. E. A quantitative densitometric method for the rapid separation and quantitation of the major tissue and lipoprotein lipids by high-performance thin-layer chromatography. I. Sample preparation, chromatography, and densitometry. J Chromatogr. 1984 Apr 13;307(1):65–79. doi: 10.1016/s0378-4347(00)84073-6. [DOI] [PubMed] [Google Scholar]
  35. Schmitz G., Fischer H., Beuck M., Hoecker K. P., Robenek H. Dysregulation of lipid metabolism in Tangier monocyte-derived macrophages. Arteriosclerosis. 1990 Nov-Dec;10(6):1010–1019. doi: 10.1161/01.atv.10.6.1010. [DOI] [PubMed] [Google Scholar]
  36. Shimano H., Ohsuga J., Shimada M., Namba Y., Gotoda T., Harada K., Katsuki M., Yazaki Y., Yamada N. Inhibition of diet-induced atheroma formation in transgenic mice expressing apolipoprotein E in the arterial wall. J Clin Invest. 1995 Feb;95(2):469–476. doi: 10.1172/JCI117687. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Sing C. F., Davignon J. Role of the apolipoprotein E polymorphism in determining normal plasma lipid and lipoprotein variation. Am J Hum Genet. 1985 Mar;37(2):268–285. [PMC free article] [PubMed] [Google Scholar]
  38. Utermann G., Langenbeck U., Beisiegel U., Weber W. Genetics of the apolipoprotein E system in man. Am J Hum Genet. 1980 May;32(3):339–347. [PMC free article] [PubMed] [Google Scholar]
  39. Walter M., Gerdes U., Seedorf U., Assmann G. The high density lipoprotein- and apolipoprotein A-I-induced mobilization of cellular cholesterol is impaired in fibroblasts from Tangier disease subjects. Biochem Biophys Res Commun. 1994 Nov 30;205(1):850–856. doi: 10.1006/bbrc.1994.2742. [DOI] [PubMed] [Google Scholar]
  40. Wang-Iverson P., Gibson J. C., Brown W. V. Plasma apolipoprotein secretion by human monocyte-derived macrophages. Biochim Biophys Acta. 1985 Apr 25;834(2):256–262. doi: 10.1016/0005-2760(85)90163-8. [DOI] [PubMed] [Google Scholar]
  41. Zhang W. Y., Gaynor P. M., Kruth H. S. Apolipoprotein E produced by human monocyte-derived macrophages mediates cholesterol efflux that occurs in the absence of added cholesterol acceptors. J Biol Chem. 1996 Nov 8;271(45):28641–28646. doi: 10.1074/jbc.271.45.28641. [DOI] [PubMed] [Google Scholar]
  42. von Eckardstein A. Cholesterol efflux from macrophages and other cells. Curr Opin Lipidol. 1996 Oct;7(5):308–319. doi: 10.1097/00041433-199610000-00009. [DOI] [PubMed] [Google Scholar]

Articles from Journal of Clinical Investigation are provided here courtesy of American Society for Clinical Investigation

RESOURCES