基于超高效液相色谱串联质谱联用法的HMG-CoA还原酶抑制剂的筛选
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
甲羟戊酸通路(mevalonate pathway,MVA)是一条极其复杂的生化通路,该通路在一系列酶的调控作用下最终能够生成对人体至关重要的终产物:胆固醇、多萜类、类异戊二烯、辅酶Q以及异戊烯腺嘌呤等。而对通路中的调控酶3-羟基-3-甲基戊二酰辅酶A还原酶(3‐Hydroxy‐3‐methylglutaryl coenzyme A,HMGCR)的研究是胆固醇代谢研究中的核心内容。HMGCR是肝脏中胆固醇合成的限速酶,是整个胆固醇代谢过程中第一个也是最重要的酶。研究发现抑制该酶的活力能够降低血液中胆固醇的含量,降低患心脑血管疾病的风险,尤其是能够有效控制高血压、冠心病以及动脉粥样硬化等疾病。
     HMGCR基因广泛存在于生物界中,在原核、真核和古生物界中均有表达。通过序列比对分析HMGCR分为两个亚型:真核HMGCR(class I)和原核HMGCR(class II)。其中以人类为代表的真核生物的HMGCR归于还原酶class I。HMGCR基因位于人类第5号染色体,包括20个外显子,19个内含子,编码26kb的基因。所有哺乳动物的HMGCR都位于内质网膜上,人类的HMGCR蛋白由888个氨基酸残基组成。该蛋白被分为两个相邻的区域,N端是跨膜功能区,通过自身以短环连接的八个跨膜片段牢牢固定在内质网膜上。中间有109个氨基酸残基组成的连接区。C端是它的催化结构域,HMGCR通过这一区域发挥其催化活性。
     目前,临床治疗高胆固醇症的药物主要为他汀类药物。该药能够竞争性的抑制肝脏中合HMGCR的活性,从而降低胆固醇的合成速率,达到降低血脂的目的。虽然他汀类药物在抑制HMGCR方面有显著效果,但其副作用近年来也屡见报道,主要体现在肌肉疼痛以及肌肉无力、抽搐、血清肌酸激酶(CK)水平偏高等,其中危害较大的是肌肉横纹肌溶解。此外,对肝脏以及肾脏的损伤主要是转氨酶升高,但其原因尚不明确。也有人认为长期肝脏酶类指标异常易导致非酒精性脂肪肝。基于上述他汀类药物可能引起的并发症,开发更安全更有效的HMGCR的抑制剂成为当下的研究热点。
     天然产物诸如中药、茶叶等具有廉价易得,对身体危害较小等特点而被广泛关注。因此本研究克隆并纯化出人HMGCR的催化结构域,并从天然产物中筛选其有效的抑制剂。
     我们以人肝癌细胞HepG2cDNA为模板,通过PCR扩增HMGCR催化结构域基因,然后将其克隆到pGex‐HisC3载体中,并将重组质粒转入大肠杆菌Rosstta DE3plysS中,加入IPTG诱导表达,最后通过亲和层析获得了融合蛋白GST‐△HMGCR。而后建立了用超高效液相色谱电喷雾串联质谱仪(UPLC‐ESI‐MS/MS)检测酶促反应体系中还原型烟酰胺腺嘌呤二核苷酸磷酸(NADPH)浓度变化,来检测HMGCR酶活并快速筛选其抑制剂的方法。
     以往针对该酶的主要检测方法有放射化学分析法、分光光度计法以及高效液相法(HPLC)。但前者由于对身体危害较大,较少被使用。分光光度计法是目前普遍使用的方法,该方法方便快速,但对底物溶液的损耗量较大且结果不够精确。NADPH极性太大,在C18色谱柱里几乎没有保留,且很多天然产物抑制剂都有很强的紫外吸收,因而HPLC法无法将NADPH同抑制剂等酶反应体系中的其他物质分开,导致在筛选HMGCR抑制剂的时候容易造成结果不准确的问题。故而我们利用UPLC‐ESI‐MS/MS法检测HMGCR酶反应体系中NADPH含量。该方法线性相关系数好,定量范围低,灵敏度高,节省了底物,降低了HMGCR抑制剂研发的成本。
     我们考察了HMGCR酶的活性,结果表明,我们纯化的GST-△HMGCR比活力约为2400U/mg,GST‐△HMGCR在6分钟内显示了良好的线性关系。
     茶叶是东亚,尤其是中国人的日常饮料,具有很好的保健功效,能够抗衰老、防癌、杀菌、消炎、瘦身等。并具有明显的抑制血脂增高的功效,且价格低廉,副作用小,是潜在的治疗与血脂偏高相关疾病的研究目标。虽然茶叶的功效日益受到关注,但是其降脂机理尚不清楚。为此,我们制备了不同种类的茶溶液,并从中筛选HMGCR的抑制剂,从实验结果看,同红茶以及普洱茶相比,绿茶能够明显的抑制HMGCR的活性,当其水提物浓度为1mg/mL时,抑制率可以达到42.9%。该结果提示绿茶中可能存在某些可以抑制HMGCR的物质。鉴于此,我们对绿茶的组份进行了进一步的筛选。
     根据以往报导,绿茶的重要成份EGCG(表没食子儿茶素没食子酸酯)对癌症、糖尿病、肥胖以及心脑血管疾病均有一定的预防治疗作用。EGCG能够抑制诸如11β‐甾类脱氢酶、5α‐还原酶、芳香酶等与固醇相关的酶。经过实验发现,EGCG还对抑制HMGCR的活性有比较明显的作用。当EGCG浓度达到1mM时,抑制率可以达到46.3%。
     但是,进一步研究表明,EGCG只有在存在丙三醇的条件下才能够抑制HMGCR的活性,而缺少丙三醇的反应体系中,EGCG则对HMGCR没有明显的抑制效果。并且随着丙三醇浓度的增高,EGCG对HMGCR的抑制作用逐渐加强。当丙三醇浓度达到600mM(5.4%)时,其抑制效果最为明显。但之后,抑制效果又随着丙三醇浓度的增大而逐步下降。应用分子docking软件进行分子动力模拟分析,结果显示,HMGCR‐EGCG‐丙三醇三者结合的自由能确实低于EGCG单独与HMGCR结合的自由能。因此,我们推测很可能是丙三醇促进了HMGCR同EGCG形成复合物,致使底物不能进入酶的活性中心。在丙三醇的协同作用下,EGCG同HMGCR的相互作用力明显增强。
     最后我们以HepG2细胞为模型,在细胞水平上研究了EGCG的降胆固醇作用,以及对HMGCR mRNA和蛋白表达水平的影响。结果表明EGCG能够降低细胞胆固醇水平,但是不能降低HMGCR mRNA和蛋白表达水平,说明EGCG不是通过下调HMGCR转录以及翻译水平从而降低胆固醇内源性合成。提示其可能同他汀类药物一样,通过抑制HMGCR的活性以下调胆固醇的合成。
The MVA pathway is a complex biochemical pathway required for thegeneration of several fundamental end-products including cholesterol, isoprenoids,dolichol, ubiquinone, and isopentenyladenine. At the heart of this pathway is therate-limiting enzyme,3-hydroxy-3-methylglutaryl CoA reductase. It is widelyacknowledged that HMGCR has been recognized as the rate-limiting enzyme insynthesis of cholesterol. The degradation of the reductase can reduce serumcholesterol levels and dramatically decrease the risk of cardiovascular andcerebrovascular diseases, essential hypertension, coronary heart diseases, andatherosclerosis.
     Comparison of the sequence of HMGR has revealed the existence of twoclasses of this enzyme. The class I enzymes was found in eukaryotes and somearchaea, and the class II found in certain eubacteria and the archaea.In allmammalian species that have been studied to datereductase localizes to membranesof the endoplasmic reticulum (ER) and consists of888amino acids that can beseparated into two contiguous domains. The N-terminal domain of reductase isintegrated into membranes by virtue of eight membrane-spanning segments that areseparated by short loops. The C-terminal domain of reductase projects into thecytosol and exerts all of the enzymatic activity.
     Statins lower cholesterol levels by specifically inhibiting HMGCR, a keyenzyme in the cholesterol biosynthesis pathway. These drugs significantly reducecardiovascular end points and are among the most commonly prescribedmedications. but their side effects are occasionally serious. A well-knowncomplication of statins use is musculoskeletal symptoms. Few patients develop anautoimmune myopathy even after the statins are discontinued. In addition, the use ofstatins may elevate serum transaminases, induce a statin-induced inhibition ofproximal tubular reabsorption of protein and have deleterious effects on the peripheral nervous system. In addition, The damage on the liver and kidney ismainly elevated transaminase which occurs after the compensatory increasedaccompany with the resulting dose-dependent drug. but the reason is not yet clear. Itis suggested that long-term liver enzymes indicators abnormalities lead tonon-alcoholic fatty liver. On the basis of data available from above, statins therapymay involve some risks of potential complications. Therefore, the development ofsafer inhibitors of HMGCR with less serious side effects has become the main studyconcern in recent years.
     Natural products such as traditional Chinese medicine, tea are widespreadconcern because their cheap and easy to get, smaller or even no toxic effects to thehealth. So in the present study, we cloned and purified the catalytic domain ofhuman HMGCR(△HMGCR) and screened its inhibitors from natural products.
     Total RNAs were extracted from Human Liver Cells (HepG2), the cDNAs weresynthesized from the polyadenylated mRNA, the Catalytic Domain of HMGCR wasamplified by PCR and then the truncated enzyme was purified by GST Resincolumn. A rapid and accurate method has been developed for screening HMGCRinhibitors by measuring the concentration of NADPH in the enzymatic reactionsystem using ultra performance liquid chromatography-electrospray ionizationtandem mass spectrometry.
     Traditional detection methods for the enzyme are radiochemical method,spectrophotometer and HPLC. But the former is less used for its great harm. thespectrophotometer method is commonly used method for its convenient and fast, butthe method is waste in the substrate solution and the results are not accurate enough.NADPH polarity is too high, so it was almost no reservations in the C18column,many of the natural product inhibitors have very strong UV absorption, and thusNADPH can not be separated from the other substances in the enzyme reactionsystem by HPLC. The UPLC-ESI-MS/MS we used has a good linear correlationcoefficient, it can save the substrate and reduce the cost of the HMGCR inhibitor developed for the lower quantitative range.
     We analyzed activity of HMGCR and screened inhibitors in the traditionalChinese medicine, tea and other natural products. The results showed that△HMGCR shows a good linear relationship in the first6minutes.
     Teas are the East Asia, especially the Chinese people's day-to-day drinks. theyhave many benefits, such as anti-aging, anti-cancer, sterilization, anti-inflammatory,slimming, significantly lower the blood lipids. So they become potential researchobjectives treatment to high blood lipids related diseases.
     We prepared the different kinds of tea solution, and screened HMGCR inhibitor.It shows that green tea can inhibit HMGCR compared with Pu'er and black tea.when its concentration is100μg/mL, the inhibition rate reach42.95%. The resultsshow that green tea can inhibit cholesterol synthesis by inhibiting HMGCR enzymeactivity. we further screen inhibitors from its subdivided components.
     Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol compoundin green tea. As a natural product with less serious side effects, it has been used toprevent cancer, obesity, diabetes and cardiovascular disease. EGCG can inhibit somesteroid-related enzymes, such as11β-hydroxysteroid dehydrogenase,5α-reductaseand aromatase, but it is ineffective in the inhibition of HMGCR. However, ourresults showed that EGCG exhibits exciting inhibitory ability against HMGCR.Subsequent study indicated that EGCG is able to inhibit HMGCR with the additionof some glycerol to the reaction system. The inhibitory effects of HMGCR enhancedwith the increase in concentration of glycerol. When the concentration reached up to600mM (5.4%), the best inhibition was observed. Afterwards, the inhibitory effectgradually reduced as the concentration surpassed600mM.
     In order to explore to role that glycerol played in this process, the analysis ofmolecular dynamics simulation was conducted on HMGCR-EGCG-glycerolinteractions. The3D structure of HMGCR was adopted. Through the model ofdynamics simulation, we speculate that EGCG and HMGCR form certain complex so that substrates are prevented from penetrating into the active center. The resultsrevealed that the affinity between EGCG and HMGCR is significantly stronger inthe synergy of glycerol.
     Moreover, EGCG can decrease cellular total cholesterol in HepG2cells withoutchanging HMGCR mRNA and protein levels after24hrs incubation compared tocontrol.
引文
[1] World Health Organization. World Health Statistics Annual:report of WHO ScientificGroup[R].Genva,Switzerland:WHO,1998.
    [2] Thorvaldsen P, Asplund K, Kuulasmaa K, et al. Stroke incidence, casefatality, andmortality in the WHO MONICA project[J]. Stroke,1995,26:361-367.
    [3]中华心血管病杂志编委会血脂异常对策专题组:血脂异常防治建议[J].中华心血管病杂志,1997,25(3):169-175.
    [4] X Zhang, A Patel, H Horibe, Z Wu, F Barzi, et al. Cholesterol, coronary heart disease,and stroke in the Asia Pacific region[J]. International Journal of Epidemiology,2003,32:563–572.
    [5] Stamler J, Daviglus ML, Garside DB, Dyer AR, Greenland P, Neaton JD.Relationship of baseline serum cholesterol levels in3large cohorts of younger mento long-term coronary, cardiovascular, and all-cause mortality and to longevity[J].JAMA,2000,284:311-318.
    [6] Neaton JD, Wentworth D. Serum cholesterol, blood pressure, cigarette smoking, anddeath from coronary heart disease. Overall findings and differences by age for316,099white men. Multiple Risk Factor Intervention Trial Research Group[J].Arch Intern Med,1992,152:56-64.
    [7] Verschuren WM, Jacobs DR, Bloemberg BP, et al. Serum total cholesterol andlong-term coronary heart disease mortality in different cultures. Twenty-five-yearfollow-up of the seven countries study[J]. JAMA,1995,274:131–136.
    [8] HW Chen, AA Kandutsch, C Waymouth. Inhibition of cell growth by oxygenatedderivatives of cholesterol[J]. Nature,1974,251,419-421.
    [9] Kai Simons,ElinaIkonen. How Cells Handle Cholesterol[J]. Science,2000, Vol.290,No.5497, pp.1721-1726.
    [10] Goldstein JL, Brown MS Regulation of the mevalonate pathway[J]. Nature,1990,343:425–430.
    [11] Hedl M,Tabernero L,Stauffacher CV,et a1.Class II3-hydroxy-3-methylglutarylcoenzyme A reductases[J].J Bacteriol,2004,l86(7):1927—1932.
    [12] Manuel Rodr guez-Concepción, Albert Boronat. Elucidation of the MethylerythritolPhosphate Pathway for Isoprenoid Biosynthesis in Bacteria and Plastids. AMetabolic Milestone Achieved through Genomics [J]. Plant Physiology,2002,130:1079-1089.
    [13] Veloso D, Cleland W, and Porter,J.W. pH properties and chemical mechanism ofaction of3-hydroxy-3-methylglutaryl coenzyme A reductase[J]. Biochemistry,1981,20:887–894.
    [14] Wang Y, Darnay B G, and Rodwell V W. Identification of the principal catalyticallyimportant acidic residue of3-hydroxy-3-methylglutaryl coenzyme A reductase[J]. J.Biol. Chem,1990,265:21634-21641.
    [15] Darnay B G, Wang Y. and Rodwell V W. Identification of the catalytically importanthistidine of3-hydroxy-3-methylglutaryl coenzyme A reductase[J]. Biol. Chem,1992,267:15064–15070.
    [16] Frimpong K, and Rodwell V W. The active site of hamster3-hydroxy-3-methylglutaryl-CoAreductase resides at the subunit interface and incorporatescatalytically essential acidic residues from separate polypeptides[J]. J. Biol. Chem,1994a,269:1217–1221.
    [17] Frimpong,K. and Rodwell,V.W. Catalysis by Syrian hamster3-hydroxy-3-methylglutaryl-coenzyme A reductase. Proposed roles of histidine865, glutamate558, and aspartate766[J]. J. Biol. Chem,1994b269:11478–11483.
    [18] P A Edwards,J Ericsson. STEROLS AND ISOPRENOIDS:Signaling MoleculesDerived from the Cholesterol Biosynthetic Pathway[J]. Annu. Rev Biochem,1999,68:157-185.
    [19] Boucher Y,H Huber,S L Haridon,et a1.Bacterial origin for the isoprenoidbiosynthesis enzyme HMG-CoA reductase of the archaeal orders thermoplasmatalesand archacoglobales[J].Mo1.Biol.Evol,2001,18(7):1378-1388.
    [20] Bochar D A, Stauffacher C V, and Rodwell V W. Sequence comparisons reveal twoclasses of3-hydroxy-3-methylglutaryl coenzyme A reductase[J]. Mol.Genet.Metab,1999,66:122–127.
    [21] Hampton R, Dimster-Denk D, and Rine J. The biology of HMG-CoA reductase:thepros of contra-regulation[J]. Trends Biochem.Sci,1996,21:140–145.
    [22] Ness GC, Spindler CD, Moffler MH. Purification of3-hydroxylglutaryl rcoenzyme Areductase from rat liver[J]. Arch Biochem Biophys,1979,197:493-499.
    [23] Edwards PA, Lemongello D, Fogelman AM. Purification and properties of rat liver3-hydroxy-3-methylglutaryl coenzyme A reductase[J]. Biochim Biophys Acta,1979,574:123-135.
    [24] Brown MS, Dana SE, Dietschy JM, Siperstein MD.3-Hydroxy-3-methylglutarylcoenzyme A reductase. Solubilization and purification of a cold-sensitivemicrosomal enzyme[J]. J Biol Chem,1973,248:4731-4738.
    [25] Liscum L, Finer-Moore J, Stroud RM, et al. Domain structure of3-hydroxy-3-methylglutaryl coenzyme A reductase, a glycoprotein of the endoplasmicreticulum[J]. J Biol Chem,1985,260:522-530.
    [26] Roitelman J, Olender EH, Bar-Nun S, Dunn Jr WA, Simoni RD. Immunologicalevidence for eight spans in the membrane domain of3-hydroxy-3-methylglutarylcoenzyme A reductase: implications for enzyme degradation in the endoplasmicreticulum[J]. J Cell Biol,1992,117:959-973.
    [27] Gertler FB, Chiu CY, Richter-Mann L, Chin DJ. Developmental and metabolicregulation of the Drosophila melanogaster3-hydroxy-3-methylglutaryl coenzyme Areductase[J]. Mol Cell Biol,1988,8:2713-2721.
    [28] Gil G, Faust JR, Chin DJ, Goldstein JL, Brown MS. Membranebound domain of HMGCoA reductase is required for sterolenhanced degradation of the enzyme[J]. Cell,1985,41:249-258.
    [29] Skalnik DG, Narita H, Kent C, Simoni RD. The membrane domain of3-hydroxy-3-methylglutaryl-coenzyme A reductase confers endoplasm-ic reticulumlocalization and sterol-regulated degradation onto beta-galactosidase[J]. J Biol Chem,1988,263:6836-6841.
    [30] Brown M.S, Dana S E, Dietschy J M, and Siperstein M D.3-hydroxy-3-methylglutaryl coenzyme A reductase. Solubilization and purification of acold-sensitive microsomal enzyme[J]. J.Biol Chem,1973,248:4731-4738.
    [31] E S Istvan, M Palnitkar, S K Buchanan, J Deisenhofer. Crystal structure of the catalyticportion of human HMG-CoA reductase: insights into regulation of activity andcatalysis[J]. EMBO J,2000,19:819-830.
    [32] Edwards,P.A., Kempner,E.S., Lan,S.F. and Erickson,S.K.Functional size of rat hepatic3-hydroxy-3-methylglutaryl coenzyme A reductase as determined by radiationinactivation[J]. J.Biol. Chem,1985,260:10278-10282.
    [33] Ness G C, Pendleton L C, and McCreery M J. In situ Determination of the functionalsize of hepatic3-hydroxy-3-Methylglutaryl-CoAreductase by radiation inactivationanalysis.Biochim.Biophys[J].Acta,1988,953:361-364.
    [34] Eva S Istvan, Maya Palnitkar, SusanK. Buchanan and Johann Deisenhofe-rCrystalstructure of the catalytic portion of human HMG-CoA reductase: insights intoregulation of activity and catalysis[J].The EMBO Journal,2000,Vol.19No.5pp.819-830.
    [35] Brown M S, Faust J R, Goldstein J L, Kaneko I, and Endo A. Induction of3-hydroxy-3-methylglutaryl coenzyme A reductaseactivi-ty in human fibroblastsincubated with compactin (ML-236B), acompetive inhibitor of the reductase[J].J.Biol.Chem,1978,253:1121-1128.
    [36] Endo A, and Hasumi K. Biochemical aspect of HMG-CoAreductase inhibitors[J].Adv.Enzyme Regul,1989,28:53-64.
    [37] Corsini A, Maggi F M, and Catapano A L. Pharmacology of competitive inhibitors ofHMG-CoA reductase[J]. Pharmacol.Res.1995,31:9-27.
    [38] Friesen JA,and V W Rodwell.The3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductases[J].Genome Bio,2004,5:248.
    [39] Tabemero L,Rodwell VW:Stauffacher CV Crystal structrue of a statin bound to a classlIHydroxymethylglutaryl-CoA Reducta[J]. Biochem,2003,278(22):19933-19938.
    [40] Friesen JA,and V W Rodwell.The3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductases[J].Genome Bio,2004,5:248.
    [41] Frimpong K and Rodwell V W. Catalysis by Syrian Hamster3-Hydroxy-3-methylglutaryl—coenzyme A Reductase[J].JBC,1994,269(15):11478-11483.
    [42] ES Istvan, M Palnitkar, SK Buchanan,et al. Crystal structure of the catalytic portion ofhuman HMG-CoA reductase: insights into regulation of activity and catalysis[J]. TheEMBO Journal,2000,19:819-830.
    [43] Johnson JM, et al. Genome-wide survey of human alternative pre-mRNA splicing withexon junction microarrays[J]. Science,2003,302:21-41-2144.
    [44] M S Brown, J L Goldstein. A proteolytic pathway that controls the cholesterol contentof membranes, cells, and blood[J]. Proc Natl. Acad.Sci,1999,96:11041-11048.
    [45] Gil G, Faust JR, Chin DJ, Goldstein JL, Brown MS. Membranebound domain ofHMG-CoA reductase is required for sterolenhanced degradation of the enzyme[J].Cell,1985,41:249-258.
    [46] Skalnik DG, Narita H, Kent C, Simoni RD. The membrane domain of3-hydroxy-methylglutaryl-coenzyme A reductaseconfers endoplasmic reticulum localization andsterol-regulated degradation onto beta-galactosidase[J]. J BiolChem,1988,263:6836-6841.
    [47] Ravid T, Doolman R, Avner R, Harats D, Roitelman J. The ubiquitin-proteasomepathway mediates the regulated degradation of Mammalian3-hydroxy-3-methylglutaryl-coenzyme reductase[J]. J Biol Chem,2000,275:35840-35847.
    [48] Inoue S, Bar-Nun S, Roitelman J, Simoni RD. Inhibition ofdegradation of3-hydroxy-3-methylglutaryl-coenzyme A reductasein vivo by cysteine protease inhibitors[J]. JBiolChem,1991,266:13311-13317.
    [49] Nohturfft A, Brown MS, Goldstein JL. Topology of SREBP cleavage-activatingprotein,a polytopic membrane protein with a sterol-sensing domain[J]. J BiolChem,1998,273:17243-17250.
    [50] Yabe D,Brown M S,Goldstein J L. Insig-2,a second endoplasmic reticulum protein thatbinds SCAP and blocks export of sterol regulator element-binding proteins[J]. TheNational Academy of Science of USA,2002:99(20):12753-12758.
    [51] DeBose-Boyd RA, et al. Transport-dependent proteolysis of SREBP:relocation ofsite-1protease from Golgi to ER obviates the need for SREBP transport to Golgi[J].Cell,1999,99(7):703-712.
    [52] Hua X, Nohturfft A, Goldstein JL, Brown MS. Sterol resistance in CHO cells traced topoint mutation in SREBP cleavage-activating protein[J]. Cell,1996,87:415-426.
    [53] Rawson RB, DeBose-Boyd R, Goldstein JL, Brown MS. Failure to cleave sterolregulatory element-binding proteins (SREBPs) causes cholesterol auxotrophy inChinese hamster ovary cells with genetic absence of SREBP cleavage-activatingprotein[J]. BiolChem,1999,274:28549-28556.
    [54] DeBose-Boyd RA, Brown MS, Li WP, et al. Transport-dependent proteolysis ofSREBP: relocation of site-1protease from Golgi to ER obviates the need for SREBPtransport to Golgi[J]. Cell1999,99:703-712.
    [55] Nohturfft A, Yabe D, Goldstein JL, Brown MS, Espenshade PJ. Regulated step incholesterol feedback localized to budding of SCAP from ER membranes[J]. Cell,2000,102:315-323.
    [56] Goldstein JL, DeBose-Boyd RA, Brown MS. Protein sensors for membrane sterols[J].Cell,2006,124:35-46.
    [57] Sun L P, Li L, Goldstein J L, et al. Insig Required for Sterol-mediated Inhibition ofScap/SREBP Binding to COPII Proteins in Vitro[J]. Journal of Biological Chemistry,2005,280(28):26483-26490.
    [58] Gimpl G, Burger K, Fahrenholz F. A closer look at the cholesterol sensor. Biochemical[J]. Sciences,2002,27(12):596-599
    [59] Yang T, Espenshade P J, Wright M E, et al. Crucial step in Cholesterol Homeostasis:Sterols Promote Binding of SCAP to INSIG-1, a MembraneProtein that FacilitatesRetention of SREBPs in ER[J]. European Journal of Clinical Investigation,2002,110(4):489-500.
    [60] Sever N, Song BL, Yabe D, et al. Insig-dependent ubiquitination and degradation ofmammalian3-hydroxy-3-methylglutaryl-CoA reductase stimulated by sterols andgeranylgeraniol[J]. J BiolChem,2003,278:52479-52490.
    [61] Lee PC, Sever N, DeBose-Boyd RA. Isolation of sterol-resistant Chinese hamsterovary cells with genetic deficiencies in both Insig-1and Insig-2[J]. J BiolChem,2005,280:25242-25249.
    [62] Sever N, Yang T, Brown MS, Goldstein JL, DeBose-Boyd RA.Accelerated degradationof HMG CoA reductase mediated bybinding of insig-1to its sterol-sensing domain[J].Mol Cell,2003,11:25-33.
    [63] Sever N, Song BL, Yabe D, et al. Insig-dependent ubiquitinationand degradation ofmammalian3-hydroxy-3-methylglutaryl-CoAreductase stimulated by sterols andgeranylgeraniol[J]. J BiolChem,2003,278:52479-52490.
    [64] Yang T, Espenshade PJ, Wright ME, et al. Crucial step in cholesterol homeostasis:sterols promote binding of SCAP to INSIG-1,a membrane protein that facilitatesretention of SREBPs[J]. ER.Cell,2002,110:489-500.
    [65] Yabe D, Brown MS, Goldstein JL. Insig-2, a second endoplasmic reticulum protein thatbinds SCAP and blocks export of sterol regulatory element-binding proteins[J].ProcNatlAcadSci USA,2002,99:12753-12758.
    [66] Inoue S, Bar-Nun S, Roitelman J, Simoni RD. Inhibition of degradation of3-hydroxy-3-methylglutaryl-coenzyme A reductase in vivo by cysteine protease inhibitors[J]. JBiolChem,1991,266:13311-13317.
    [67] Pickart CM. Mechanisms underlying ubiquitination[J]. Annu Rev Biochem,2001,70:503-533.
    [68] Song BL, Sever N, DeBose-Boyd RA. Gp78, a membraneanchoredubiquitin ligase,associates with Insig-1and couples sterol-regulated ubiquitination to degradation ofHMG-CoA reductase[J]. Mol Cell,2005,19:829-840.
    [69] Cao J, Wang J, Qi W, et al. Ufd1is a cofactor of gp78and plays a key role incholesterol metabolism by regulating the stability of HMG-CoA reductase[J]. CellMetab,2007,6:115-128.
    [70] Ye Y, Meyer HH, Rapoport TA. The AAA ATPase Cdc48/p97and its partners transportproteins from the ER into the cytosol[J].Nature,2001,414:652-656.
    [71] Russell A, DeBose-Boyd, et al. Feedback regulation of cholesterol synthesis: sterol-acceleratedubiquitination and degradation of HMG-CoA reductase[J]. Cell Research,2008,18:609-621.
    [72] Espenshade PJ, Hughes AL. Regulation of sterol synthesis in eukaryotes[J]. Annu RevGenet,2007,41:401–27.
    [73] Carling D, Clarke PR, Zammit VA, Hardie DG. Purification and characterization of theAMP-activated protein kinase.Co-purifica-tion of acetyl-CoA carboxylase kinase and3-hydroxy-3-methylglu-taryl-CoAreductase kinase activities[J]. Eur J Biochem,1989,186:129–136.
    [74] Hardie DG. Minireview:the AMP-activated protein kinase cascade: the key sensor ofcellular energy status[J]. Endocrinology,2003,144:5179–83.
    [75] Towler MC, Hardie DG. AMP-activated protein kinase in metabolic control and insulinsignaling[J]. Circ Res,2007,100:328–41.
    [76] P.R. Clarke, D.G. Hardie, Regulation of HMG-CoA reductase: identification of the sitephosphorylated by the AMP-activated protein kinase in vitro and in intact rat liver[J].EMBO J,1990,9:2439^2446.
    [77] J.A. Friesen, V.W. Rodwell. Protein Engineering of the HMG-CoA Reductase ofPseudomonas mevalonii. Construction of Mutant Enzymes Whose Activity IsRegulated by Phosphorylation and Dephosphorylation[J]. Biochemistry,1997,36:1157-1162.
    [78] R V Omkumar, B G Darnay, V W Rodwell. Modulation of Syrian hamster3-hydroxy-3-methylglutaryl-CoA reductase activity by phosphorylation Role of serine871[J].Biol.Chem,1994,269:6810-6814.
    [79] Z H Beg, J A Stonik, H B Brewer Jr. Phosphorylation of hepatic3-hydroxy-3-methylglutaryl coenzyme A reductase and modulation of its enzymic activity bycalcium-activated and phospholipid-dependent protein kinase[J]. J.Biol.Chem,1985,260:1682-1687.
    [80] Z.H. Beg, J.A. Stonik, H.B. Brewer Jr. Phosphorylation and modulation of the enzymicactivity of native and protease-cleaved purified hepatic3-hydroxy-3-methylglutaryl-coenzyme A reductase by a calcium/calmodulin-dependent protein kinase[J].J.Biol.Chem,1987,262:13228-13240.
    [81] Ness G C, Wiggins L, Zhao Z. Insulin increases hepatic3-hydroxy-3-methylglutarylcoenzyme A reductase mRNA and immune reactive protein levels in diabetic rats[J].Arch Biochem Biophys,1994,309:1932-1940.
    [82] Ness G C, Zhao Z, Wiggin s L. Insulin and glucagons modulate hepatic3-hydroxyl-3-methylglu taryl coenzyme A reductase activity by affecting immunoreactive proteinlevels[J]. J Biol Chem,1994,269:29168229172.
    [83] Hen H, Shapiro D J. Nucleotide sequence and estrogen induction of Xen op uslaevis3-hydroxyl-3-methylglutaryl coenzyme A reductase [J]. J BiolChem,1990,265:462224629.
    [84] Shefer S, Nguyen L B, Sal en G. Differing effect s of cholesterol and taurocholate onsteady-state hepatic HMG-CoA reductase and cholesterol7-hydroxylase activities andmRNA levels inthe rat[J]. J Lipid Res,1992,33:119321200.
    [85] Duckworth P F, Vlahcevic Z R, Stu der E J. Effect of hydrophobic-bile acids on3-hydroxyl-3-methylglutaryl coenzyme Areductase activity and mRNA levels in therat[J]. J BiolChem,1991,266:941329418.
    [86] Endo,A, M Kuroda, and Y Tsujita. ML-236A, ML-236B, and ML-236C, new inhibitorsof chloesterogenesis produced by penicilliumcitrinum[J]. J.Antibiot,1976,29:1346-1348.
    [87] Downs JR,Clearfield M,Weis S,et al. Primary prevention of acute coronary eventswith lovastatin in men and women with average cholesterol levels of AFCAPS/TexCAPS[J]. JAMA,1998,279(20):1615.
    [88]范建高,蔡晓波.他汀类药物肝脏安全性问题[J].中华心血管病杂志,2007,35(6):589.
    [89]仝其广,胡大一.他汀类药物安全性问题[J].中国实用内科杂志,2007,27(9):655-656.
    [90] De SauvageNolting PR, Buirma RJ, Hutten BA, Kastelein JJ, and the Dutch ExPRESSInvestigator Group. Two-year efficacy andsafety of simvastatin80mg in familialhypercholesterolemia (the Examination of Probands and Relatives in Statin StudiesWith Familial Hypercholesterolemia [ExPRESSfh])[J]. Am J Cardiol,2002,90:181-184.
    [91] Bruckert E, Hayem G, Dejager S, Yau C, Begaud B. Mild to moderate muscularsymptoms with high-dosage statin therapy in hyperlipidemic patients-the PRIMOstudy[J].Cardiovasc Drugs Ther,2005,19:403-414.
    [92] Franc S, Dejager S, Bruckert E, Chauvenet M, Giral P, Turpin G. A comprehensivedescription of muscle symptoms associated with lipid-lowering drugs[J]. CardiovascDrugs Ther,2003,17:459–465.
    [93] Graham DJ, Staffa JA, Shatin D, Andrade SE, Schech SD, La Grenade L, et al.Incidence of hospitalized rhabdomyolysis in patients treated with lipid-loweringdrugs[J]. JAMA,2004,292:2585-2590.
    [94] Soininen K, Niemi M, Kilkki E, Strandberg T, Kivisto KT. Muscle symptomsassociated with statins: a series of twenty patients[J]. Basic Clin Pharmacol Toxicol,2006,98:51–54.
    [95] Needham M, Fabian V, Knezevic W, Panegyres P, ZilkoP,Mastaglia FL. Progressivemyopathy with up-regulation of MHC-Iassociated with statin therapy[J].NeuromusculDisord,2007,17:194-200.
    [96] Grable-Esposito P, Katz berg HD, Green berg SA, Srinivasan J,Katz J, Amato AA.Immune-mediated necrotizing myopathy associatedwith statins[J]. Muscle Nerve,2010,41:185-90.
    [97] Christopher-Stine L, Casciola-Rosen LA, Hong G, Chung T,Corse AM, Mammen AL.A novel autoantibody recognizing200-kd and100-kd proteins is associated with animmune-mediated necrotizing myopathy[J]. Arthritis Rheum,2010,62:2757-2766.
    [98] Andrew L. Mammen, Tae Chung, et al. Autoantibodies Against3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase in Patients With Statin-AssociatedAutoimmune Myopathy[J]. ARTHRITIS&RHEUMATISM,2011,Vol.63, No.3,pp713-721.
    [99] CHRISTINA A. BURSILLAND PAUL D. ROACH. Modulation of CholesterolMetabolism by the Green Tea Polyphenol(-)-EpigallocatechinGallate in CulturedHuman Liver (HepG2) Cells[J]. Agric.Food Chem,2006,54:1621-1626.
    [100] XIAO-LI YE, WEN-WEN HUANG, ZHUCHEN, et al. Synergetic Effect andStructure-Activity Relationship of3-Hydroxy-3-methylglutaryl Coenzyme AReductase Inhibitors from CrataeguspinnatifidaBge[J]. Agric.Food Chem,2010,58:3132-3138.
    [101] Jang HoonSung, Sung-joonLEE, KwanHwaParK, and Tae WaeMoon. Isofla-vonesInhibit3-Hydroxy-3-methylglutaryl Coenzyme A Reductase in Vitro[J].Biosci.Biotechnol Biochem,200468(2):428-432.
    [102]赵博华,钱之玉,陈真.西红花酸对大鼠血浆胆固醇的调节作用及其机制研究[J].中国新药杂志,2009,18(14):1347-1351.
    [103]曹兰秀,周永学,顿宝生.女贞子总黄酮对高脂模型大鼠脂代谢的影响[J].第四军医大学学报,2009,30(12):2129-2132.
    [104]王树立,赵勤黄,郭郁成.菊花等中药水煎剂对离体大鼠肝细胞微粒体经甲基戊二酞辅酶还原酶的作用[J].生物化学杂志,1988,4(6):517-524.
    [105]胡旭光,郭姣,贝伟剑,胡因铭,黄利华,曹扬.复方贞术调脂方调节HMG-CoA还原酶活性成分的快速筛选[J]. Traditional Chinese Drug Research&ClinicalPharmacology,2010, Vol.21No.5.
    [106] Brown MS, Dana SE, Dietschy JM, Siperstein MD.3-Hydroxy-3-methyl-glutarylcoenzyme A reductase. Solubilization and purification of a cold-sensitive microsomalenzyme[J]. J Biol Chem,1973,248:4731-4738.
    [107] Liscum L, Finer-Moore J, Stroud RM, et al. Domain structure of3-hydroxy-3-methylglutaryl coenzyme A reductase, a glycoprotein of the endoplasmic reticulum[J].J Biol Chem,1985,260:522-530.
    [108] Roitelman J, Olender EH, Bar-Nun S, Dunn Jr WA, Simoni RD. Immunologicalevidence for eight spans in the membrane domain of3-hydroxy-3-methylglutarylcoenzyme A reductase: implications for enzyme degradation in the endoplasmicreticulum[J]. Cell Biol,1992,117:959-973.
    [109] Luskey KL, Stevens B. Human3-hydroxy-3-methylglutaryl coenzyme A reductase.Conserved domains responsible for catalytic activity and sterol-regulateddegradation[J]. J Biol Chem,1985,260:10271-10277.
    [110] Gertler FB, Chiu CY, Richter-Mann L, Chin DJ. Developmental and metabolicregulation of the Drosophila melanogaster3-hydroxy-3-methylglutaryl coenzyme Areductase[J]. Mol Cell Biol,1988,8:2713-2721.
    [111] Inoue S, Bar-Nun S, Roitelman J, Simoni RD. Inhibition of degradation of3-hydroxy-3-methylglutaryl-coenzyme A reductase in vivo by cysteine proteaseinhibitors[J]. J Biol Chem,1991,266:13311-13317.
    [112] Hampton RY. Genetic analysis of hydroxymethylglutaryl-coenzyme A reductaseregulated degradation[J]. Curr Opin Lipidol,1998,9:93-97.
    [113] Hampton RY, Koning A, Wright R, Rine J. In vivo examination of membrane proteinlocalization and degradation with green fluorescent protein[J]. Proc Natl Acad Sci,1996,93:828-833.
    [114] Cauley JA, et al. Statin use and breast cancer: Prospective results from theWomen’sHealth Initiative[J]. J Natl Cancer,2006,98:700-707.
    [115] Kwan ML, Habel LA, Flick ED, Quesenberry CP, Caan B. Post-diagnosis statin useandbreast cancer recurrence in a prospective cohort study of early stage breast cancersurvivors[J]. Breast Cancer Res Treat,2008,109:573–579.
    [116] Bonovas S, Filioussi K, Flordellis CS, et al. Statins and the risk ofcolorectal cancer: ameta-analysis of18studies involving more than1.5million patients[J]. J ClinOncol,2007,25:3462-3468.
    [117] Clendening JW, et al. Exploiting the mevalonate pathway to distinguish statin-sensitivemultiple myeloma[J]. Blood,2010,115:4787-4797.
    [118] Vitols S, Norgren S,Juliusson G,et al. Multilevel regulation of low-density lipoproteinreceptor and3-hydroxy-3-methylglutaryl coenzyme A reductase gene expression innormal and leukemic cells[J]. Blood,1994,84(8):2689-2698.
    [119] Lewis KA, HolsteinSA, Hohl RJ. Lovastatin alters the isoprenoid biosynthetic pathwayin acute myelogenous leukemia cells in vivo[J]. Leuk Res,2005,29(5):527-533.
    [120] Sutter AP, MaaserK, et al. Cell cycle arrest and apoptosis induction in hepatocellularcarcinoma cells by HMG-COA reductase inhibitors.Synergisticantiproliferative actionwith ligands of the peripheral benzodiazepine receptor[J]. J Hepatology,2005:43(5):808-816.
    [121] James W. Clendening, Aleks Pandyra, Paul C. Boutros, et al. Dysregulation of themevalonate pathway promotes transformation[J]. PNAS,2010,34:15051–15056.
    [122] Lipkin SM, et al. Genetic variation in3-hydroxy-3-methylglutaryl CoA reductasemodifies the chemopreventive activity of statins for colorectal cancer[J]. Cancer Prev,2010,3:597-603.
    [123] Burkhardt R, et al. Common SNPs in HMGCR in micronesians and whites associatedwith LDL-cholesterol levels affect alternative splicing of exon13[J]. ArteriosclerThromb VascBio,2008,l28:2078-2084.
    [124] Medina MW, Gao F, Ruan W, Rotter JI, Krauss RM. Alternative splicing of3-hydroxy-3-methylglutarylcoenzyme A reductase is associated with plasmalow-densitylipoprotein cholesterol response to simvastatin[J]. Circulation,2008,118:355–362.
    [125] Brown M S,Goldstein J L.Multivalent feedback regulation of HMG-CoA reductase, acontrol mechanism coordinating isoprenoid synthesis and cell growth[J]. J. LipidRes,1980,21(7):505-517.
    [126] WANG Rui-Yong,JI Mi-Na,WANG Rui-Qiang,CHAI Ya-Hui,ZHANG Lu,MAHai-Ming.Chinese J.Anal.Chem,2009,37(A03):339-339.
    [127] Mozzicafreddo M,Cuccioloni M,Eleuteri A M,Angeletti M.Rapid reversephase-HPLC assay of HMG-CoA reductase activity[J].J.Lipid Res,2010,51(8):2460-2463.
    [128] Apffel A,Chakel J A,Fischer S,Lichtenwalter K,Hancock W S.Analysis ofOligonucleotides by HPLC Electrospray Ionization Mass Spectrometry[J]. Anal.Chem,1997,69(7):1320-1325.
    [129] Fountain K J,Gilar M,Gebler J C.Rapid Commun. Analysis of native and chemicallymodified oligonucleotides by tandem ion-pair reversed-phase high-performance liquidchromatography/electrospray ionization mass spectrometry[J]. Mass Spectrom,2003,17(7):646-653.
    [130] XU Yan-Ting,WANG Xiu-Juan,SU Xiao-Lin,XU Ji-Lin,CHEN Hai-Min,CHENJuan-Juan, YAN Xiao-jun. Synthesis and Characterization of New1,3,5-Triazine-Based Compounds Exhibiting Aggregation-Induced Emission andMechanochromism[J].Chinese J.Anal.Chem,2011,39(12):1798-1804.
    [131] Jang Hoon SUNG, Sung-Joon LEE, Kwan Hwa PARK and Tae WhaMOON.Isoflavones Inhibit3-Hydroxy-3-methylglutaryl Coenzyme A Reductase inVitro[J]. Biosci. Biotechnol. Biochem,2004,68(2):428-432.
    [132] Bursill C A, Roach P D. Modulation of Cholesterol metabolism by the green teaPolyphenol(-)-epigallocatechingallate in cultured human liver (HepG2) Cells[J]. J.Agric.Food Chem,2006,54,1621-1626.
    [133] Liao S, Kao Y.H, Hiipakka R A. Green tea: Biochemical and biological basis for healthbenefits[J]. Vitam.Horm,2001,62:91–94.
    [134] Yang C S, Wang Z Y. Tea and cancer[J]. J.Natl.Cancer Inst,1993,85:1038–1049.
    [135] Mitscher L A, Jung M, Shankel D, Dou J.H, Steele L, Pillai S P. Chemoprotection: areview of the potential therapeutic antioxidant properties of green tea (Camelliasinensis) and certain of its constituents[J]. Med.Res.Rev,1997,17:327-365.
    [136] Lin J.k, Liang Y C, Lin-Shiau S Y. Cancer chemoprevention by tea polyphenolsthrough mitotic signal transduction blockade[J]. Biochem.Pharmacol,1999,58:911-915.
    [137] Muramatsu K, Fukuyo M, Hara Y. Effect of green tea catechins on plasma cholesterollevel in cholesterol-fed rats[J]. J. Nutr.Sci. Vitaminol,1986,32:613-622.
    [138] Matsumoto N, Ishigaki F, Ishigaki A, Iwashima H, Hara Y. Reduction of blood glucoselevels by tea catechin[J]. Biosci.Biotech.Biochem,1993,57:525-527.
    [139] Sarr F S, André C, Guillaume Y C. Statins (HMG-coenzyme A reductase inhibitors)-biomimetic membrane binding mechanism investigated by molecularchromatography[J]. J.Chromatogr.B,2008,868:20-27.
    [140] Perchellet J P, Perchellet E M, Crow K R, Buszek K R, Brown N, Ellappan S, Gao G,Luo D, Minatoya M, Lushington G H. Novel synthetic inhibitors of3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity that inhibit tumor cellproliferation and are structurally unrelated to existing statins[J]. Int.J.Mol.Med,2009,246:633-643.
    [141] Mc Taggart F, Buckett L, Davidson R, Holdgate G, McCormick A, Schneck D, Smith G,Warwick M. Preclinical and clinical pharmacology of Rosuvastatin, a new3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor[J]. Am.J Cardiol,2001,87:28B–32B.
    [142] Rao S, Porter D.C, Chen X, Herliczek T, Lowe M, Keyomarsi K. Lovastatin-mediatedG1arrest is through inhibition of the proteasome, independent ofhydroxymethylglutaryl-CoA reductase[J]. Proc.Natl.Acad.Sci,1999,96:7797–7802.
    [143] Marc IRG, Anne B, Valerie L, Elvira LP. Up-regulation of lowdensity lipoproteinreceptor in human hepatocytes is induced by sequestration of free cholesterol in theendosomal/lysosomal compartment[J]. Biochem.Pharm,2004,67:2281-2289.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700