Cholesterol 7 alpha-hydroxylase also known as cholesterol 7-alpha-monooxygenase or cytochrome P450 7A1 (CYP7A1) is an enzyme that in humans is encoded by the CYP7A1 gene.[1]
Function [edit]
Cholesterol 7 alpha-hydroxylase is the rate-limiting enzyme in the synthesis of bile acid from cholesterol via the classic pathway, catalyzing the formation of 7-alpha-hydroxycholesterol. CYP7A1 is a cytochrome P450 heme enzyme that oxidizes cholesterol using molecular oxygen.
It is downregulated by Sterol regulatory element-binding proteins (SREBP) when plasma cholesterol levels are low. It is upregulated by the nuclear receptor LXR (liver X receptor) when cholesterol (to be specific, oxysterol) levels are high.[2]
The effect of this upregulation is to increase the production of bile acids and reduce the level of cholesterol in hepatocytes.
Interactive pathway map [edit]
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
Clinical significance [edit]
Deficiency of this enzyme will increase the possibility of cholesterol gallstones.[3]
References [edit]
- ^ Cohen JC, Cali JJ, Jelinek DF, Mehrabian M, Sparkes RS, Lusis AJ, Russell DW, Hobbs HH (September 1992). "Cloning of the human cholesterol 7 alpha-hydroxylase gene (CYP7) and localization to chromosome 8q11-q12". Genomics 14 (1): 153–61. doi:10.1016/S0888-7543(05)80298-8. PMID 1358792.
- ^ Chawla A, Saez E, Evans RM (September 2000). "Don't know much bile-ology". Cell 103 (1): 1–4. doi:10.1016/S0092-8674(00)00097-0. PMID 11051540.
- ^ Paumgartner G, Sauerbruch T (November 1991). "Gallstones: pathogenesis". Lancet 338 (8775): 1117–21. doi:10.1016/0140-6736(91)91972-W. PMID 1682550.
Further reading [edit]
- Davis RA, Miyake JH, Hui TY, Spann NJ (2002). "Regulation of cholesterol-7alpha-hydroxylase: BAREly missing a SHP.". J. Lipid Res. 43 (4): 533–43. PMID 11907135.
- Kim HJ, Park HY, Kim E, et al. (2010). "Common CYP7A1 promoter polymorphism associated with risk of neuromyelitis optica.". Neurobiol. Dis. 37 (2): 349–55. doi:10.1016/j.nbd.2009.10.013. PMID 19850125.
- Holmes MV, Shah T, Vickery C, et al. (2009). "Fulfilling the promise of personalized medicine? Systematic review and field synopsis of pharmacogenetic studies.". In Luo, Yuan. PLoS ONE 4 (12): e7960. doi:10.1371/journal.pone.0007960. PMC 2778625. PMID 19956635.
- Lipkin SM, Chao EC, Moreno V, et al. (2010). "Genetic variation in 3-hydroxy-3-methylglutaryl CoA reductase modifies the chemopreventive activity of statins for colorectal cancer". Cancer Prev Res (Phila Pa) 3 (5): 597–603. doi:10.1158/1940-6207.CAPR-10-0007. PMID 20403997.
- Lambrinoudaki I, Kaparos G, Rizos D, et al. (2009). "Apolipoprotein E and paraoxonase 1 polymorphisms are associated with lower serum thyroid hormones in postmenopausal women". Clin. Endocrinol. (Oxf) 71 (2): 284–90. doi:10.1111/j.1365-2265.2008.03476.x. PMID 19018779.
- Poduri A, Khullar M, Bahl A, et al. (2009). "A combination of proatherogenic single-nucleotide polymorphisms is associated with increased risk of coronary artery disease and myocardial infarction in Asian Indians". DNA Cell Biol. 28 (9): 451–60. doi:10.1089/dna.2009.0887. PMID 19558216.
- Li T, Chanda D, Zhang Y, et al. (2010). "Glucose stimulates cholesterol 7alpha-hydroxylase gene transcription in human hepatocytes". J. Lipid Res. 51 (4): 832–42. doi:10.1194/jlr.M002782. PMC 2842145. PMID 19965590.
- Kovár J, Lenícek M, Zimolová M, Vítek L, Jirsa M, Pitha J (2010). "Regulation of diurnal variation of cholesterol 7alpha-hydroxylase (CYP7A1) activity in healthy subjects". Physiol Res 59 (2): 233–8. PMID 19537927.
- Chien KL, Wang KC, Chen YC, et al. (2010). "Common sequence variants in pharmacodynamic and pharmacokinetic pathway-related genes conferring LDL cholesterol response to statins". Pharmacogenomics 11 (3): 309–17. doi:10.2217/pgs.09.160. PMID 20235787.
- Saito A, Kawamoto M, Kamatani N (2009). "Association study between single-nucleotide polymorphisms in 199 drug-related genes and commonly measured quantitative traits of 752 healthy Japanese subjects". J. Hum. Genet. 54 (6): 317–23. doi:10.1038/jhg.2009.31. PMID 19343046.
- Nelson DR, Zeldin DC, Hoffman SM, et al. (2004). "Comparison of cytochrome P450 (CYP) genes from the mouse and human genomes, including nomenclature recommendations for genes, pseudogenes and alternative-splice variants". Pharmacogenetics 14 (1): 1–18. doi:10.1097/00008571-200401000-00001. PMID 15128046.
- Li T, Ma H, Park YJ, et al. (2009). "Forkhead box transcription factor O1 inhibits cholesterol 7alpha-hydroxylase in human hepatocytes and in high fat diet-fed mice". Biochim. Biophys. Acta 1791 (10): 991–6. doi:10.1016/j.bbalip.2009.05.004. PMC 2743791. PMID 19463968.
- Chakrabarti B, Dudbridge F, Kent L, et al. (2009). "Genes related to sex steroids, neural growth, and social-emotional behavior are associated with autistic traits, empathy, and Asperger syndrome". Autism Research 2 (3): 157–77. doi:10.1002/aur.80. PMID 19598235.
- Barcelos AL, Chies R, Almeida SE, et al. (2009). "Association of CYP7A1 -278A>C polymorphism and the response of plasma triglyceride after dietary intervention in dyslipidemic patients". Braz. J. Med. Biol. Res. 42 (6): 487–93. PMID 19448895.
- Voora D, Shah SH, Reed CR, et al. (2008). "Pharmacogenetic predictors of statin-mediated low-density lipoprotein cholesterol reduction and dose response". Circ Cardiovasc Genet 1 (2): 100–6. doi:10.1161/CIRCGENETICS.108.795013. PMC 2995295. PMID 20031551.
- Schwarz M, Lund EG, Russell DW (1998). "Two 7 alpha-hydroxylase enzymes in bile acid biosynthesis". Curr. Opin. Lipidol. 9 (2): 113–8. doi:10.1097/00041433-199804000-00006. PMID 9559267.
- Beigneux A, Hofmann AF, Young SG (2002). "Human CYP7A1 deficiency: progress and enigmas". J. Clin. Invest. 110 (1): 29–31. doi:10.1172/JCI16076. PMC 151039. PMID 12093884.
- Ruaño G, Bernene J, Windemuth A, Bower B, Wencker D, Seip RL, Kocherla M, Holford TR, Petit WA, Hanks S (February 2009). "Physiogenomic comparison of edema and BMI in patients receiving rosiglitazone or pioglitazone". Clin. Chim. Acta 400 (1–2): 48–55. doi:10.1016/j.cca.2008.10.009. PMID 18996102.
- Schaap FG, van der Gaag NA, Gouma DJ, Jansen PL (2009). "High expression of the bile salt-homeostatic hormone fibroblast growth factor 19 in the liver of patients with extrahepatic cholestasis". Hepatology 49 (4): 1228–35. doi:10.1002/hep.22771. PMID 19185005.
- Srivastava A, Choudhuri G, Mittal B (2010). "CYP7A1 (-204 A>C; rs3808607 and -469 T>C; rs3824260) promoter polymorphisms and risk of gallbladder cancer in North Indian population". Metab. Clin. Exp. 59 (6): 767–73. doi:10.1016/j.metabol.2009.09.021. PMID 20005541.
External links [edit]
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| CYP2 |
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| CYP3 (CYP3A) |
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| CYP4 |
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| CYP5-20 |
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| CYP21-51 |
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