Genomes and Genes
Experts and Doctors on steroid hydroxylases in Dallas, Texas, United States
Locale: Dallas, Texas, United States
Topic: steroid hydroxylases
- Kerr T, Saeki S, Schneider M, Schaefer K, Berdy S, Redder T, et al. Loss of nuclear receptor SHP impairs but does not eliminate negative feedback regulation of bile acid synthesis. Dev Cell. 2002;2:713-20 pubmed..We conclude that input from three negative regulatory pathways controls bile acid synthesis. One is mediated by SHP, and two are SHP independent and invoked by liver damage and changes in bile acid pool size. ..
- Kotti T, Ramirez D, Pfeiffer B, Huber K, Russell D. Brain cholesterol turnover required for geranylgeraniol production and learning in mice. Proc Natl Acad Sci U S A. 2006;103:3869-74 pubmed..We conclude that cholesterol turnover in brain activates the mevalonate pathway and that a constant production of geranylgeraniol in a small subset of neurons is required for LTP and learning. ..
- Vega G, Weiner M, Kolsch H, von Bergmann K, Heun R, Lutjohan D, et al. The effects of gender and CYP46 and apo E polymorphism on 24S-hydroxycholesterol levels in Alzheimer's patients treated with statins. Curr Alzheimer Res. 2004;1:71-7 pubmed..Polymorphisms of CYP46 or apo E do not explain levels of oxysterol or non-HDL cholesterol or the responsiveness to statin treatment in this study. ..
- Quan G, Xie C, Dietschy J, Turley S. Ontogenesis and regulation of cholesterol metabolism in the central nervous system of the mouse. Brain Res Dev Brain Res. 2003;146:87-98 pubmed..In the adult, however, synthesis exceeds the need for structural cholesterol so that there is a constant excretion of sterol from the CNS into the plasma at a rate of about 0.023 mg/day...
- Cali J, Hsieh C, Francke U, Russell D. Mutations in the bile acid biosynthetic enzyme sterol 27-hydroxylase underlie cerebrotendinous xanthomatosis. J Biol Chem. 1991;266:7779-83 pubmed..These findings underscore the essential role played by sterols in the central nervous system and suggest that mutations in other sterol metabolizing enzymes may contribute to diseases with neurological manifestations. ..
- Schwarz M, Lund E, Lathe R, Bjorkhem I, Russell D. Identification and characterization of a mouse oxysterol 7alpha-hydroxylase cDNA. J Biol Chem. 1997;272:23995-4001 pubmed..The liver thus maintains the capacity to synthesize 7alpha-hydroxylated bile acids regardless of dietary composition, underscoring the central role of 7alpha-hydroxylated bile acids in lipid metabolism. ..
- Lund E, Kerr T, Sakai J, Li W, Russell D. cDNA cloning of mouse and human cholesterol 25-hydroxylases, polytopic membrane proteins that synthesize a potent oxysterol regulator of lipid metabolism. J Biol Chem. 1998;273:34316-27 pubmed
- Russell D. Oxysterol biosynthetic enzymes. Biochim Biophys Acta. 2000;1529:126-35 pubmed..This article focuses on the properties of these enzymes. ..
- Bauman D, Bitmansour A, McDonald J, Thompson B, Liang G, Russell D. 25-Hydroxycholesterol secreted by macrophages in response to Toll-like receptor activation suppresses immunoglobulin A production. Proc Natl Acad Sci U S A. 2009;106:16764-9 pubmed publisher..The suppression of IgA class switching in B cells by a macrophage-derived sterol in response to TLR activation provides a mechanism for local and systemic negative regulation of the adaptive immune response by the innate immune system. ..
- Li Hawkins J, Lund E, Turley S, Russell D. Disruption of the oxysterol 7alpha-hydroxylase gene in mice. J Biol Chem. 2000;275:16536-42 pubmed..A failure to catabolize oxysterols in the male kidney may lead to a decrease in de novo sterol synthesis. ..
- Schwarz M, Lund E, Setchell K, Kayden H, Zerwekh J, Bjorkhem I, et al. Disruption of cholesterol 7alpha-hydroxylase gene in mice. II. Bile acid deficiency is overcome by induction of oxysterol 7alpha-hydroxylase. J Biol Chem. 1996;271:18024-31 pubmed..In older animals, an alternate pathway of bile acid synthesis involving an inducible oxysterol 7alpha-hydroxylase plays a crucial role in lipid and bile acid metabolism. ..
- Xie C, Lund E, Turley S, Russell D, Dietschy J. Quantitation of two pathways for cholesterol excretion from the brain in normal mice and mice with neurodegeneration. J Lipid Res. 2003;44:1780-9 pubmed..The other probably involves the movement of cholesterol or one of its metabolites across the blood-brain barrier and may more closely mirror sterol turnover in pools such as glial cell membranes and myelin. ..
- Schwarz M, Lund E, Russell D. Two 7 alpha-hydroxylase enzymes in bile acid biosynthesis. Curr Opin Lipidol. 1998;9:113-8 pubmed..cDNAs encoding these proteins have been isolated and used to define two evolutionarily conserved pathways that produce 7 alpha-hydroxylated bile acids. ..
- Cheng J, Levine M, Bell N, Mangelsdorf D, Russell D. Genetic evidence that the human CYP2R1 enzyme is a key vitamin D 25-hydroxylase. Proc Natl Acad Sci U S A. 2004;101:7711-5 pubmed..These data identify CYP2R1 as a biologically relevant vitamin D 25-hydroxylase and reveal the molecular basis of a human genetic disease, selective 25-hydroxyvitamin D deficiency. ..
- Lund E, Guileyardo J, Russell D. cDNA cloning of cholesterol 24-hydroxylase, a mediator of cholesterol homeostasis in the brain. Proc Natl Acad Sci U S A. 1999;96:7238-43 pubmed..We conclude that the cloned cDNAs encode cholesterol 24-hydroxylases that synthesize oxysterols in neurons of the brain and that secretion of 24S-hydroxycholesterol from this tissue in the mouse is developmentally regulated. ..
- Jelinek D, Andersson S, Slaughter C, Russell D. Cloning and regulation of cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme in bile acid biosynthesis. J Biol Chem. 1990;265:8190-7 pubmed..These results suggest that bile acids and sterols are able to alter the transcription of the 7 alpha-hydroxylase gene and that this control explains the previously observed feedback regulation of bile acid synthesis. ..
- Cali J, Russell D. Characterization of human sterol 27-hydroxylase. A mitochondrial cytochrome P-450 that catalyzes multiple oxidation reaction in bile acid biosynthesis. J Biol Chem. 1991;266:7774-8 pubmed
- Halford R, Russell D. Reduction of cholesterol synthesis in the mouse brain does not affect amyloid formation in Alzheimer's disease, but does extend lifespan. Proc Natl Acad Sci U S A. 2009;106:3502-6 pubmed publisher..These studies suggest that reducing de novo cholesterol synthesis in the brain will not substantially alter the course of Alzheimer's disease, but may confer a survival advantage. ..
- Andersson S, Davis D, Dahlback H, Jornvall H, Russell D. Cloning, structure, and expression of the mitochondrial cytochrome P-450 sterol 26-hydroxylase, a bile acid biosynthetic enzyme. J Biol Chem. 1989;264:8222-9 pubmed..Blotting experiments revealed that the mRNA for this enzyme is expressed in many tissues and that it is encoded by a low copy number gene in the rabbit genome. ..
- Cheng J, Motola D, Mangelsdorf D, Russell D. De-orphanization of cytochrome P450 2R1: a microsomal vitamin D 25-hydroxilase. J Biol Chem. 2003;278:38084-93 pubmed..CYP2R1 mRNA is abundant in the liver and testis, and present at lower levels in other tissues. The data suggest that CYP2R1 is a strong candidate for the microsomal vitamin D 25-hydroxylase. ..
- Repa J, Lund E, Horton J, Leitersdorf E, Russell D, Dietschy J, et al. Disruption of the sterol 27-hydroxylase gene in mice results in hepatomegaly and hypertriglyceridemia. Reversal by cholic acid feeding. J Biol Chem. 2000;275:39685-92 pubmed..These studies confirm the importance of CYP27 in bile acid synthesis and they reveal an unexpected function of the enzyme in triacylglycerol metabolism. ..
- Li Hawkins J, Lund E, Bronson A, Russell D. Expression cloning of an oxysterol 7alpha-hydroxylase selective for 24-hydroxycholesterol. J Biol Chem. 2000;275:16543-9 pubmed
- Bhasker C, Adler B, Dee A, John M, Kagimoto M, Zuber M, et al. Structural characterization of the bovine CYP17 (17 alpha-hydroxylase) gene. Arch Biochem Biophys. 1989;271:479-87 pubmed..Whether the consensus CREB/ATF sequence is associated with the cAMP-mediated transcription of the CYP17 gene remains to be elucidated. ..
- Schwarz M, Russell D, Dietschy J, Turley S. Alternate pathways of bile acid synthesis in the cholesterol 7alpha-hydroxylase knockout mouse are not upregulated by either cholesterol or cholestyramine feeding. J Lipid Res. 2001;42:1594-603 pubmed