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. 1991 Aug;88(2):553–560. doi: 10.1172/JCI115339

Lipolysis exposes unreactive endogenous apolipoprotein E-3 in human and rat plasma very low density lipoprotein.

E Sehayek 1, U Lewin-Velvert 1, T Chajek-Shaul 1, S Eisenberg 1
PMCID: PMC295385  PMID: 1864965

Abstract

Endogenous apolipoprotein E in VLDL is poorly expressed in receptor binding processes. Yet catabolism of VLDL-remnants by cellular receptors depends on functional apo E molecules. To better understand remnant catabolism phenomena, we determined the metabolism of VLDL and post-lipolysis VLDL by cultured cells. Partial lipolysis was achieved by incubation of VLDL with lipoprotein lipase in vitro (human) or recirculation (rat) in supradiaphragmatic animals. Lipolyzed VLDL exhibit metabolic activities 2-20-fold higher than control VLDL, that are saturable and dependent on the presence of LDL receptors. The ligand responsible for receptor interaction of lipolyzed VLDL (apo E or apo B-100) and its source (endogenous or transferred) was studied with monoclonal antibodies and with lipoproteins from E-3/3 and E-2/2 subjects. The data unequivocally proved that lipolysis causes exposure of unreactive endogenous apo E-3 at the VLDL surface, possibly by a change of conformation of the protein. Apo B-100 becomes biologically expressed only in lipolyzed VLDL-III. Lipolyzed VLDL, however, is less reactive to exogenous apo E-3 than control VLDL indicating that endogenous and exogenous apo E are oriented differently in VLDL. It is proposed that VLDL delivers triglycerides to tissues when apo E is unreactive but becomes a remnant after the protein becomes exposed and directs the particles from lipoprotein lipase sites to cellular receptors.

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Selected References

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  1. Bierman E. L., Eisenberg S., Stein O., Stein Y. Very low density lipoprotein "remnant" particles: uptake by aortic smooth muscle cells in culture. Biochim Biophys Acta. 1973 Nov 2;329(1):163–169. doi: 10.1016/0304-4165(73)90021-4. [DOI] [PubMed] [Google Scholar]
  2. Bilheimer D. W., Eisenberg S., Levy R. I. The metabolism of very low density lipoprotein proteins. I. Preliminary in vitro and in vivo observations. Biochim Biophys Acta. 1972 Feb 21;260(2):212–221. doi: 10.1016/0005-2760(72)90034-3. [DOI] [PubMed] [Google Scholar]
  3. Brown M. S., Goldstein J. L. A receptor-mediated pathway for cholesterol homeostasis. Science. 1986 Apr 4;232(4746):34–47. doi: 10.1126/science.3513311. [DOI] [PubMed] [Google Scholar]
  4. Chajek T., Eisenberg S. Very low density lipoprotein. Metabolism of phospholipids, cholesterol, and apolipoprotein C in the isolated perfused rat heart. J Clin Invest. 1978 Jun;61(6):1654–1665. doi: 10.1172/JCI109086. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Eisenberg S., Friedman G., Vogel T. Enhanced metabolism of normolipidemic human plasma very low density lipoprotein in cultured cells by exogenous apolipoprotein E-3. Arteriosclerosis. 1988 Sep-Oct;8(5):480–487. doi: 10.1161/01.atv.8.5.480. [DOI] [PubMed] [Google Scholar]
  6. Eisenberg S., Rachmilewitz D. Metabolism of rat plasma very low density lipoprotein. II. Fate in circulation of apoprotein subunits. Biochim Biophys Acta. 1973 Dec 20;326(3):391–405. doi: 10.1016/0005-2760(73)90140-9. [DOI] [PubMed] [Google Scholar]
  7. Friedman G., Gavish D., Vogel T., Eisenberg S. Cellular metabolism of human plasma intermediate-density lipoprotein (IDL). Biochim Biophys Acta. 1990 May 1;1044(1):118–126. doi: 10.1016/0005-2760(90)90226-n. [DOI] [PubMed] [Google Scholar]
  8. Gianturco S. H., Gotto A. M., Jr, Hwang S. L., Karlin J. B., Lin A. H., Prasad S. C., Bradley W. A. Apolipoprotein E mediates uptake of Sf 100-400 hypertriglyceridemic very low density lipoproteins by the low density lipoprotein receptor pathway in normal human fibroblasts. J Biol Chem. 1983 Apr 10;258(7):4526–4533. [PubMed] [Google Scholar]
  9. Gianturco S. H., Gotto A. M., Jr, Jackson R. L., Patsch J. R., Sybers H. D., Taunton O. D., Yeshurun D. L., Smith L. C. Control of 3-hydroxy-3-methylglutaryl-CoA reductase activity in cultured human fibroblasts by very low density lipoproteins of subjects with hypertriglyceridemia. J Clin Invest. 1978 Feb;61(2):320–328. doi: 10.1172/JCI108942. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Goldstein J. L., Basu S. K., Brown M. S. Receptor-mediated endocytosis of low-density lipoprotein in cultured cells. Methods Enzymol. 1983;98:241–260. doi: 10.1016/0076-6879(83)98152-1. [DOI] [PubMed] [Google Scholar]
  11. Havel R. J. George Lyman Duff memorial lecture. Role of the liver in atherosclerosis. Arteriosclerosis. 1985 Nov-Dec;5(6):569–580. doi: 10.1161/01.atv.5.6.569. [DOI] [PubMed] [Google Scholar]
  12. Herz J., Hamann U., Rogne S., Myklebost O., Gausepohl H., Stanley K. K. Surface location and high affinity for calcium of a 500-kd liver membrane protein closely related to the LDL-receptor suggest a physiological role as lipoprotein receptor. EMBO J. 1988 Dec 20;7(13):4119–4127. doi: 10.1002/j.1460-2075.1988.tb03306.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Innerarity T. L., Arnold K. S., Weisgraber K. H., Mahley R. W. Apolipoprotein E is the determinant that mediates the receptor uptake of beta-very low density lipoproteins by mouse macrophages. Arteriosclerosis. 1986 Jan-Feb;6(1):114–122. doi: 10.1161/01.atv.6.1.114. [DOI] [PubMed] [Google Scholar]
  14. Innerarity T. L., Pitas R. E., Mahley R. W. Disparities in the interaction of rat and human lipoproteins with cultured rat fibroblasts and smooth muscle cells. Requirements for homology for receptor binding activity. J Biol Chem. 1980 Dec 10;255(23):11163–11172. [PubMed] [Google Scholar]
  15. Kleinman Y., Eisenberg S., Oschry Y., Gavish D., Stein O., Stein Y. Defective metabolism of hypertriglyceridemic low density lipoprotein in cultured human skin fibroblasts. Normalization with bezafibrate therapy. J Clin Invest. 1985 Jun;75(6):1796–1803. doi: 10.1172/JCI111892. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Kowal R. C., Herz J., Goldstein J. L., Esser V., Brown M. S. Low density lipoprotein receptor-related protein mediates uptake of cholesteryl esters derived from apoprotein E-enriched lipoproteins. Proc Natl Acad Sci U S A. 1989 Aug;86(15):5810–5814. doi: 10.1073/pnas.86.15.5810. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Kowal R. C., Herz J., Weisgraber K. H., Mahley R. W., Brown M. S., Goldstein J. L. Opposing effects of apolipoproteins E and C on lipoprotein binding to low density lipoprotein receptor-related protein. J Biol Chem. 1990 Jun 25;265(18):10771–10779. [PubMed] [Google Scholar]
  18. Krul E. S., Tikkanen M. J., Cole T. G., Davie J. M., Schonfeld G. Roles of apolipoproteins B and E in the cellular binding of very low density lipoproteins. J Clin Invest. 1985 Feb;75(2):361–369. doi: 10.1172/JCI111708. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Mahley R. W., Angelin B. Type III hyperlipoproteinemia: recent insights into the genetic defect of familial dysbetalipoproteinemia. Adv Intern Med. 1984;29:385–411. [PubMed] [Google Scholar]
  20. Mahley R. W., Innerarity T. L. Lipoprotein receptors and cholesterol homeostasis. Biochim Biophys Acta. 1983 May 24;737(2):197–222. doi: 10.1016/0304-4157(83)90001-1. [DOI] [PubMed] [Google Scholar]
  21. Mahley R. W., Weisgraber K. H., Hussain M. M., Greenman B., Fisher M., Vogel T., Gorecki M. Intravenous infusion of apolipoprotein E accelerates clearance of plasma lipoproteins in rabbits. J Clin Invest. 1989 Jun;83(6):2125–2130. doi: 10.1172/JCI114126. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Milne R. W., Douste-Blazy P., Marcel Y. L., Retegui L. Characterization of monoclonal antibodies against human apolipoprotein E. J Clin Invest. 1981 Jul;68(1):111–117. doi: 10.1172/JCI110225. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Oschry Y., Olivecrona T., Deckelbaum R. J., Eisenberg S. Is hypertriglyceridemic very low density lipoprotein a precursor of normal low density lipoprotein? J Lipid Res. 1985 Feb;26(2):158–167. [PubMed] [Google Scholar]
  24. Schonfeld G., Patsch W., Pfleger B., Witztum J. L., Weidman S. W. Lipolysis produces changes in the immunoreactivity and cell reactivity of very low density lipoproteins. J Clin Invest. 1979 Nov;64(5):1288–1297. doi: 10.1172/JCI109584. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Vega G. L., Grundy S. M. Mechanisms of primary hypercholesterolemia in humans. Am Heart J. 1987 Feb;113(2 Pt 2):493–502. doi: 10.1016/0002-8703(87)90620-x. [DOI] [PubMed] [Google Scholar]
  26. Vogel T., Weisgraber K. H., Zeevi M. I., Ben-Artzi H., Levanon A. Z., Rall S. C., Jr, Innerarity T. L., Hui D. Y., Taylor J. M., Kanner D. Human apolipoprotein E expression in Escherichia coli: structural and functional identity of the bacterially produced protein with plasma apolipoprotein E. Proc Natl Acad Sci U S A. 1985 Dec;82(24):8696–8700. doi: 10.1073/pnas.82.24.8696. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Weber K., Osborn M. The reliability of molecular weight determinations by dodecyl sulfate-polyacrylamide gel electrophoresis. J Biol Chem. 1969 Aug 25;244(16):4406–4412. [PubMed] [Google Scholar]
  28. Windler E., Chao Y., Havel R. J. Regulation of the hepatic uptake of triglyceride-rich lipoproteins in the rat. Opposing effects of homologous apolipoprotein E and individual C apoproteins. J Biol Chem. 1980 Sep 10;255(17):8303–8307. [PubMed] [Google Scholar]
  29. Windler E., Havel R. J. Inhibitory effects of C apolipoproteins from rats and humans on the uptake of triglyceride-rich lipoproteins and their remnants by the perfused rat liver. J Lipid Res. 1985 May;26(5):556–565. [PubMed] [Google Scholar]
  30. Yamada N., Shames D. M., Stoudemire J. B., Havel R. J. Metabolism of lipoproteins containing apolipoprotein B-100 in blood plasma of rabbits: heterogeneity related to the presence of apolipoprotein E. Proc Natl Acad Sci U S A. 1986 May;83(10):3479–3483. doi: 10.1073/pnas.83.10.3479. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Yamada N., Shimano H., Mokuno H., Ishibashi S., Gotohda T., Kawakami M., Watanabe Y., Akanuma Y., Murase T., Takaku F. Increased clearance of plasma cholesterol after injection of apolipoprotein E into Watanabe heritable hyperlipidemic rabbits. Proc Natl Acad Sci U S A. 1989 Jan;86(2):665–669. doi: 10.1073/pnas.86.2.665. [DOI] [PMC free article] [PubMed] [Google Scholar]

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