Abstract
27-Hydroxycholesterol was found in surprisingly high amounts in atherosclerotic human femoral arteries. When human macrophages were cultured in a medium containing serum, there was a significant transfer of 27-hydroxy-cholesterol and 3 beta-hydroxy-5-cholestenoic acid from the cells into the medium. Sterol 27-hydroxylase (EC 1.14.13.15) is likely to be responsible for formation of the two products as shown by use of immunoblotting, a specific inhibitor, and the 18O-labeling technique. Sterol 27-hydroxylase has the unusual ability to hydroxylate the same methyl group three times to give a carboxylic acid; thus, 3 beta-hydroxy-5-cholestenoic acid is likely to be a direct product of the enzyme. The production of these steroids increased after addition of cholesterol to the culture medium. By using deuterium-labeled cholesterol, it was ascertained that most of the oxidized products were formed from exogenous cholesterol taken up by the cells. 27-Hydroxycholesterol and 3 beta-hydroxy-5-cholestenoic acid are present in the circulation and are efficiently converted into bile acids in human liver. It is suggested that conversion of cholesterol into 27-hydroxycholesterol and 3 beta-hydroxy-5-cholestenoic acid represents a general defence mechanism for macrophages and possibly also other peripheral cells exposed to cholesterol. Absence of this defence mechanism may contribute to the premature atherosclerosis known to occur in patients with sterol 27-hydroxylase deficiency (cerebrotendinous xanthomatosis).
Full text
PDF![8592](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac28/44652/96177cf633b3/pnas01140-0294.png)
![8593](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac28/44652/8ee50a7c4a73/pnas01140-0295.png)
![8594](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac28/44652/6653065e9a36/pnas01140-0296.png)
![8595](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac28/44652/02f43e1a62b6/pnas01140-0297.png)
![8596](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ac28/44652/34acf93f20b1/pnas01140-0298.png)
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Anderson K. E., Kok E., Javitt N. B. Bile acid synthesis in man: metabolism of 7 -hydroxycholesterol- 14 C and 26-hydroxycholesterol- 3 H. J Clin Invest. 1972 Jan;51(1):112–117. doi: 10.1172/JCI106780. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Andersson S., Davis D. L., Dahlbäck H., Jörnvall H., Russell D. W. Cloning, structure, and expression of the mitochondrial cytochrome P-450 sterol 26-hydroxylase, a bile acid biosynthetic enzyme. J Biol Chem. 1989 May 15;264(14):8222–8229. [PubMed] [Google Scholar]
- Axelson M., Mörk B., Sjövall J. Occurrence of 3 beta-hydroxy-5-cholestenoic acid, 3 beta,7 alpha-dihydroxy-5-cholestenoic acid, and 7 alpha-hydroxy-3-oxo-4-cholestenoic acid as normal constituents in human blood. J Lipid Res. 1988 May;29(5):629–641. [PubMed] [Google Scholar]
- Björkhem I., Fausa O., Hopen G., Oftebro H., Pedersen J. I., Skrede S. Role of the 26-hydroxylase in the biosynthesis of bile acids in the normal state and in cerebrotendinous xanthomatosis. An in vivo study. J Clin Invest. 1983 Jan;71(1):142–148. doi: 10.1172/JCI110742. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Björkhem I. Mechanism of degradation of the steroid side chain in the formation of bile acids. J Lipid Res. 1992 Apr;33(4):455–471. [PubMed] [Google Scholar]
- Björkhem I., Nyberg B., Einarsson K. 7 alpha-hydroxylation of 27-hydroxycholesterol in human liver microsomes. Biochim Biophys Acta. 1992 Sep 22;1128(1):73–76. doi: 10.1016/0005-2760(92)90259-x. [DOI] [PubMed] [Google Scholar]
- Breuer O., Björkhem I. Simultaneous quantification of several cholesterol autoxidation and monohydroxylation products by isotope-dilution mass spectrometry. Steroids. 1990 Apr;55(4):185–192. doi: 10.1016/0039-128x(90)90109-o. [DOI] [PubMed] [Google Scholar]
- Brooks C. J., Harland W. A., Steel G. Squalene, 26-hydroxycholesterol and 7-ketocholesterol in human atheromatous plaques. Biochim Biophys Acta. 1966 Dec 7;125(3):620–622. doi: 10.1016/0005-2760(66)90055-5. [DOI] [PubMed] [Google Scholar]
- Cali J. J., Hsieh C. L., Francke U., Russell D. W. Mutations in the bile acid biosynthetic enzyme sterol 27-hydroxylase underlie cerebrotendinous xanthomatosis. J Biol Chem. 1991 Apr 25;266(12):7779–7783. [PMC free article] [PubMed] [Google Scholar]
- Dahlbäck-Sjöberg H., Björkhem I., Princen H. M. Selective inhibition of mitochondrial 27-hydroxylation of bile acid intermediates and 25-hydroxylation of vitamin D3 by cyclosporin A. Biochem J. 1993 Jul 1;293(Pt 1):203–206. doi: 10.1042/bj2930203. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dawson P. A., Van der Westhuyzen D. R., Goldstein J. L., Brown M. S. Purification of oxysterol binding protein from hamster liver cytosol. J Biol Chem. 1989 May 25;264(15):9046–9052. [PubMed] [Google Scholar]
- Dawson P. A., Van der Westhuyzen D. R., Goldstein J. L., Brown M. S. Purification of oxysterol binding protein from hamster liver cytosol. J Biol Chem. 1989 May 25;264(15):9046–9052. [PubMed] [Google Scholar]
- Fumagalli R., Galli G., Urna G. Cholestanol and 26-hydroxycholesterol in normal and atherosclerotic human aorta. Life Sci II. 1971 Jan 8;10(1):25–33. doi: 10.1016/0024-3205(71)90221-9. [DOI] [PubMed] [Google Scholar]
- Holmberg-Betsholtz I., Lund E., Björkhem I., Wikvall K. Sterol 27-hydroxylase in bile acid biosynthesis. Mechanism of oxidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,27-tetrol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid. J Biol Chem. 1993 May 25;268(15):11079–11085. [PubMed] [Google Scholar]
- Jaffe E. A., Nachman R. L., Becker C. G., Minick C. R. Culture of human endothelial cells derived from umbilical veins. Identification by morphologic and immunologic criteria. J Clin Invest. 1973 Nov;52(11):2745–2756. doi: 10.1172/JCI107470. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Javitt N. B. 26-Hydroxycholesterol: synthesis, metabolism, and biologic activities. J Lipid Res. 1990 Sep;31(9):1527–1533. [PubMed] [Google Scholar]
- Javitt N. B., Kok E., Cohen B., Burstein S. Cerebrotendinous xanthomatosis: reduced serum 26-hydroxycholesterol. J Lipid Res. 1982 May;23(4):627–630. [PubMed] [Google Scholar]
- Kaluzny M. A., Duncan L. A., Merritt M. V., Epps D. E. Rapid separation of lipid classes in high yield and purity using bonded phase columns. J Lipid Res. 1985 Jan;26(1):135–140. [PubMed] [Google Scholar]
- Kim K. S., Kubota S., Kuriyama M., Fujiyama J., Björkhem I., Eggertsen G., Seyama Y. Identification of new mutations in sterol 27-hydroxylase gene in Japanese patients with cerebrotendinous xanthomatosis (CTX). J Lipid Res. 1994 Jun;35(6):1031–1039. [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Leitersdorf E., Reshef A., Meiner V., Levitzki R., Schwartz S. P., Dann E. J., Berkman N., Cali J. J., Klapholz L., Berginer V. M. Frameshift and splice-junction mutations in the sterol 27-hydroxylase gene cause cerebrotendinous xanthomatosis in Jews or Moroccan origin. J Clin Invest. 1993 Jun;91(6):2488–2496. doi: 10.1172/JCI116484. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Levanon D., Hsieh C. L., Francke U., Dawson P. A., Ridgway N. D., Brown M. S., Goldstein J. L. cDNA cloning of human oxysterol-binding protein and localization of the gene to human chromosome 11 and mouse chromosome 19. Genomics. 1990 May;7(1):65–74. doi: 10.1016/0888-7543(90)90519-z. [DOI] [PubMed] [Google Scholar]
- Lund E., Breuer O., Björkhem I. Evidence that 24- and 27-hydroxylation are not involved in the cholesterol-induced down-regulation of hydroxymethylglutaryl-CoA reductase in mouse liver. J Biol Chem. 1992 Dec 15;267(35):25092–25097. [PubMed] [Google Scholar]
- Lund J., Anderson O., Ripe E. Characterization of a binding protein for the PCB metabolite 4,4'-bis(methylsulfonyl)-2,2',5,5'-tetrachlorobiphenyl present in bronchoalveolar lavage from healthy smokers and non-smokers. Toxicol Appl Pharmacol. 1986 May;83(3):486–493. doi: 10.1016/0041-008x(86)90231-0. [DOI] [PubMed] [Google Scholar]
- Oftebro H., Björkhem I., Skrede S., Schreiner A., Pederson J. I. Cerebrotendinous xanthomatosis: a defect in mitochondrial 26-hydroxylation required for normal biosynthesis of cholic acid. J Clin Invest. 1980 Jun;65(6):1418–1430. doi: 10.1172/JCI109806. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pedersen J. I., Oftebro H., Björkhem I. Reconstitution of C27-steroid 26-hydroxylase activity from bovine brain mitochondria. Biochem Int. 1989 Mar;18(3):615–622. [PubMed] [Google Scholar]
- Postlind H., Wikvall K. Evidence for the formation of 26-hydroxycholesterol by cytochrome P-450 in pig kidney mitochondria. Biochem Biophys Res Commun. 1989 Mar 31;159(3):1135–1140. doi: 10.1016/0006-291x(89)92227-4. [DOI] [PubMed] [Google Scholar]
- Shoda J., Toll A., Axelson M., Pieper F., Wikvall K., Sjövall J. Formation of 7 alpha- and 7 beta-hydroxylated bile acid precursors from 27-hydroxycholesterol in human liver microsomes and mitochondria. Hepatology. 1993 Mar;17(3):395–403. [PubMed] [Google Scholar]
- Skrede S., Björkhem I., Kvittingen E. A., Buchmann M. S., Lie S. O., East C., Grundy S. Demonstration of 26-hydroxylation of C27-steroids in human skin fibroblasts, and a deficiency of this activity in cerebrotendinous xanthomatosis. J Clin Invest. 1986 Sep;78(3):729–735. doi: 10.1172/JCI112633. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith L. L., Pandya N. L. Sterol metabolism. 18. On the uniqueness of the occurrence of 26-hydroxycholesterol in the human aorta. Atherosclerosis. 1973 Jan-Feb;17(1):21–30. doi: 10.1016/0021-9150(73)90131-7. [DOI] [PubMed] [Google Scholar]
- Taylor F. R., Saucier S. E., Shown E. P., Parish E. J., Kandutsch A. A. Correlation between oxysterol binding to a cytosolic binding protein and potency in the repression of hydroxymethylglutaryl coenzyme A reductase. J Biol Chem. 1984 Oct 25;259(20):12382–12387. [PubMed] [Google Scholar]
- Towbin H., Staehelin T., Gordon J. Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4350–4354. doi: 10.1073/pnas.76.9.4350. [DOI] [PMC free article] [PubMed] [Google Scholar]