唐斌+黄丹+傅强
[摘要] 目的 分析SLCO1B1的主要突变388G>A和521T>C在南昌地区汉族原发性高脂血症人群中的分布。 方法 分别采用PCR-RFLP和ARMS-PCR方法对280名居住于南昌地区汉族原发性高脂血症患者SLCO1B1的388G>A和521T>C位点进行基因分型,并对其进行Hardy-Weinberg平衡检验。 结果 280名受试者中,SLCO1B1的388G>A位点:110名为388G>A突变杂合子,141名为388G突变纯合子,分别占总人数的39.3%和50.3%,余29名为388A野生型纯合子,占总人数的10.4%,突变等位基因的发生频率为70.0%。521T>C位点:60名为521T>C突变型杂合子,6名为521C突变型纯合子,分别占总人数的21.4%和2.1%,余214名为521T野生型纯合子,占总人数的76.5%,突变等位基因的发生频率为12.9%。 结论 南昌地区汉族原发性高脂血症人群中的SLCO1B1 388G>A和521T>C突变与日本及中国汉族男性健康人群分布相似,388G>A突变率显著高于白人,521T>C突变率显著高于黑人。
[关键词] SLCO1B1;基因型;原发性高脂血症
[中图分类号] R394 [文献标识码] A [文章编号] 1673-9701(2014)34-0001-03
有机阴离子转运多肽OATP1B1是一种表达在窦状隙基底侧细胞膜上的摄入型转运体,为具有基因多态性的跨膜转运蛋白[1,2] ,由SLCO1B1基因编码,它主要分布于人的肝脏,其他还可见于肾脏、脑、小肠等器官,具有介导肝细胞膜转运内、外源性物质并对其进行代谢和消除的生理功能。转运物质包括他汀类、降糖药、利福平、血管紧张素Ⅱ 受体拮抗剂和胆汁酸、非结合型胆红素、甲状腺素、PGE和某些肽类[3],Hirouchi M[4]等和Chung JY等[5]研究发现,SLCO1B1多态性在OATP1B1的转运功能和药代动力学个体差异上起着重要作用。日本研究者报道,388G>A和521T>C是其人群中常见基因突变,频率分别为66%和15.8%[6]。然而关于南昌地区原发性高脂血症人群中的情况分别未见报道,本文拟对此作一研究,以期为原发性高脂血症患者药效和药动学的个体差异提供依据。
1 对象与方法
1.1 研究对象
参考《血脂异常防治建议》从江西省人民医院2013 年7~12月门诊就诊患者中筛选280名居住于南昌地区汉族无血源关系原发性高脂血症患者,男132例,女148例,年龄33~70 (55.8±9.2)岁;身高144~184(163.6±8.6)cm;体重40~90(66.6±10.5)kg。
1.2 方法
1.2.1 材料 引物:南昌长城生物科技有限公司合成;DNA 提取试剂:美国Pel-Freez 公司;LA Taq DNA 聚合酶,Taq DNA 聚合酶,限制性内切酶TaqI及dNTP (MBI Fermentas,Lithuania):深圳晶美生物工程有限公司。
1.2.2 DNA抽提 采取受试者清晨空腹外周EDTA抗凝静脉血5 mL,以DNA提取试剂盒提取外周血DNA。
1.2.3 基因分型 参考基因分型优化文献[7]。
1.2.3.1 388G>A分型:采用PCR-RFLP进行:其引物为:F:5-ATAATGGTGCAAATAAAGGGG-3,R:5-ACTATCTCAGGTGATGCTCTA-3。反应体系(25 μL):10×PCR Master Mix 2.5 μL,DNA模板约200 ng,前后引物各40 pmol/L,Taq酶2.0 U,0.4 mmol/L dNTP,余额体积补充纯水完成。PCR反应条件:94℃ 5 min,94℃30 s,44℃ 30 s,72℃ 30 s,38个循环,72℃ 7 min。388G>A 位点PCR扩增产物2.5%的琼脂糖凝胶对酶切产物进行电泳分型。扩增产物酶切反应体系:10 μLPCR扩增产物,1 μL的Taq I 酶,1 μL 10×H Master Mix,3 μL纯水,65℃温育4 h。2.5%的琼脂糖凝胶对酶切产物进行电泳分型。
1.2.3.2 521T>C 分型:以ARMS-PCR方法进行分型。引物:OuterP1:5-AAGTAGTTAAATTTGTAATAGAAATGC-3,InnerP1:5-GGGTCATACATGTGGATATAAGT-3,InnerP2:5-AAGCATATTACCCATGAACG-3,OuterP2:-GTAGACAAAGGGAAAGTGATCATA-3,反应体系(25 μL):10×PCR Master Mix 2.5μL,Taq酶2U,dNTP 0.4 mmol/L,hDNA模板200 ng,各引物均为40 pmol/L,余额取纯水补足。PCR反应条件:94℃ 5 min,94℃ 30 s,48℃ 30 s,72℃ 30 s,38个循环,72℃ 5 min。2.5%的琼脂糖凝胶对酶切产物进行电泳分型。
1.3 统计学分析
采用SPSS 12.0软件包进行数据分析。使用频率计数法计算基因型频率及等位基因频率,两组间比较采用卡方检验基因型是否符合Hardy-Weinberg平衡。P<0.05表示差异具有统计学意义。
2 结果
2.1 基因型的判定
388G>A基因:如图1: 2.5%的琼脂糖凝胶电泳拍照图所示:突变型杂合子:23bp、63bp、123bp与151bp等4处显示亮带;突变型纯合子:23bp 、63bp及128bp等3处显示亮带,野生型纯合子:63bp和151bp 2处显示亮带。521T>C基因:如图2:2.5%的琼脂糖凝胶电泳拍照图所显:突变型杂合:123bp、179bp与260bp等3处显示亮带;突变型纯合子:123bp 和260bp 2处显示亮带;野生型纯合子:179bp和 260bp 2处显示亮带。
2.2 基因型分布及等位基因频率分布
基因型和各等位基因的频率如表1。280名南昌地区汉族原发性高脂血症患者中,388G>A:检测出29例受试者为野生型纯合子,占总人数的10.4%;突变纯合子141例,占比为50.3%;其余110例是比例为39.3%的突变杂合子,等位基因突变发生率为70.0%。521T>C:检测出214例野生型纯合子,占总人数的76.5%;6例突变型纯合子,占2.1%,余60例突变型杂合子,占总人数的21.4%,等位基因突变发生率为12.9%。两基因观察值符合Hardy-weinberg 遗传平衡。表明本研究资料具有群体代表性(P=0.31和P=0.94)。
3 讨论
目前大多研究证实转运体及药物代谢酶的遗传多态性与药物相互作用的个体差异具有重要的相关性。近年来体内或体外研究证明摄入型转运蛋白OATP1B1在药物底物的转运代谢起着重要的作用。目前在不同研究人群中各国研究者已经发现SLCO 1B1基因(编码OATP1B1蛋白)多达20种基因突变[7]。当前研究多集中在常见的两个突变位点,位于第5外显子的388A>G与第6外显子的521T>C,上述两个位点的突变明显影响许多底物的转运活性、转运速度及与底物结合力。
本文将南昌地区汉族原发性高脂血症人群388G>A与521T>C等位基因突变分布情况与报道的中国汉族男性健康、欧美和日本人群作一比较:本研究388G>A等位基因突变频率为70.0%,显著高于白人30%的突变率(P<0.05),与报道中国汉族男性健康人群(73.4%)、黑人(74%)及日本人群(62.9%)之间无显著差异(P>0.05)。在本研究中521T>C等位基因突变率为12.9%,显著高于黑人的2%的突变率(P<0.05),与报道中国汉族男性健康人群(14.0%)、白人(14%)及日本人群(15.8%)之间无显著差异(P>0.05)[6,8,9]。上述结果表明,在不同人群中388G>A和521T>C突变率不同种族间具有显著的差异。
目前多数报道显示,SLCO1B1基因多态性明显影响其参与转运药物的药效动力学、药物毒性以及药代动力学[10]。如目前报道的广泛应用于高脂血症治疗的HMG-CoA还原酶抑制剂瑞舒伐他汀,其被SLCO1B1转运入肝而行调脂作用,熊玉卿等[11]研究报道,521T>C 位点突变影响瑞舒伐他汀药代动力学,使其转运体活性下降,增高血药浓度,可能与突变后增加瑞舒伐他汀在人体内的吸收程度,减慢消除过程有关。国外日本与德国研究者分别报道显示,521T>C野生型纯合子组血药浓度显著低于突变组,而其非肾清除率显著高于突变组。而对于388G>A的突变是否影响药效动力学、药代动力学目前研究结论不一致。德国研究者报道,388G>A突变组普伐他汀血药浓度显著升高,然而较多数体内外实验未见该突变的上述影响[12,13]。而在关于非结合胆红素水平的研究中,日本、台湾与中国大陆的研究者报道SLCO1B1521T>C突变导致个体血浆浓度明显高于非突变人群[7,14,15]。以上显示,SLCO1B1基因多态性显著影响某些药物的药代动力学及药物浓度,其研究对于临床个体化用药具有重要指导意义,如临床医师在使用涉及到该两个突变基因参与转运与代谢的底物如他汀类,抗结核药及降糖等药物时, 应参考其基因型检测结果,以期提高药物疗效及减少副作用。
综上所述:在南昌地区汉族原发性高脂血症人群中SLCO1B1的388G>A和521T>C突变比较常见,其突变率与日本、中国汉族男性健康人相近,与报道的白人和黑人频率有显著差异,提示其突变率可能与原发性高脂血症发病无关,但可能与种族有关,此种差异可能是遗传因素与环境因素等多因素的相互作用结果,具体机制有待进一步研究。
[参考文献]
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[10] Nies AT,Niemi M,Burk O,et al. Genetics is a major determinant of expression of the human hepatic uptake transporter OATP1B1,but not of OATP1B3 and OATP2B1[J].Genome Med ,2013,5 (1): 1.
[11] 熊玉卿、袁钊、温金华、等. OATP1B1 转运体的基因多态性与瑞舒伐他汀的关联[J]. 江西医药,2012,47(5):421-424.
[12] Gerloff T,Schaefer M,Mwinyi J,et al. Influence of the SLCO1B1*1b and *5 haplotypes on pravastatin's cholesterol lowering capabilities and basal sterol serum levels[J].Naunyn Schmiedebergs Arch Pharmacol,2006,373(1):45-50.
[13] Niemi M,Schaeffeler E,Lang T,et al. High plasma pravastatin concentrations are associated with single nucleotide polymorpHisms and haplotypes of organic anion transporting polypeptide-C (OATP-C,SLCO1B1)[J]. Pharmacogenetics,2004,14(7):429-440.
[14] Cui Y,K?nig J,Leier I,et al. Hepatic Uptake of Bilirubin and Its Conjugates by the Human Organic Anion Transporter SLC21A6[J]. J Biol Chem,2001,276(13): 9626–9630.
[15] Ieiri I,Suzuki H,Kimura M,et al. Influence of common variants in the pharmacokinetic genes(OATP-C,UGT1A1,and MRP2) on serum bilirubin levels in healthy subjects[J].Hepatol Res ,2004,30(2):91-95.
(收稿日期:2014-09-24)
[5] Chung JY,Cho JY,Yu KS,et al. Effect of OATP1B1 (SLCO1B1) variant alleles on the Pharmacokinetics of pitavastatin in healthy volunteers[J]. Clin Pharmacol Ther,2005,78(4):342-350.
[6] Nishizato Y,I Ieiri,Suzuki H,et al. Polymorphisms of OATP-C (SLC21A6) and OAT3 (SLC22A8) genes: consequences for pravastatin pharmacokinetics[J]. Clin PHarmacol,Ther,2003,73(6):554-565.
[7] Zhang W,He YJ,Gan Z.et al. OATP1B1 polymorphism is a major determinant of serum bilirubin level but not associated with rifampicin-mediated bilirubin elevation[J]. Clin Exp Pharmacol Physiol ,2007,34(12):1240-1244.
[8] Furihata T1,Satoh N,Ohishi T,et al. Functional analysis of a mutation in the SLCO1B1 gene (c.1628T>G) identified in a Japanese patient with pravastatin-induced myopathy. Pharmacogenomics J[J]. 2009,9(3): 185-193
[9] Xu LY,He YJ,Zhang W,et al. Organic anion transporting polypeptide-1B1 haplotypes in Chinese patients[J]. Acta Pharmacol Sin,2007,28(10):1693-1697.
[10] Nies AT,Niemi M,Burk O,et al. Genetics is a major determinant of expression of the human hepatic uptake transporter OATP1B1,but not of OATP1B3 and OATP2B1[J].Genome Med ,2013,5 (1): 1.
[11] 熊玉卿、袁钊、温金华、等. OATP1B1 转运体的基因多态性与瑞舒伐他汀的关联[J]. 江西医药,2012,47(5):421-424.
[12] Gerloff T,Schaefer M,Mwinyi J,et al. Influence of the SLCO1B1*1b and *5 haplotypes on pravastatin's cholesterol lowering capabilities and basal sterol serum levels[J].Naunyn Schmiedebergs Arch Pharmacol,2006,373(1):45-50.
[13] Niemi M,Schaeffeler E,Lang T,et al. High plasma pravastatin concentrations are associated with single nucleotide polymorpHisms and haplotypes of organic anion transporting polypeptide-C (OATP-C,SLCO1B1)[J]. Pharmacogenetics,2004,14(7):429-440.
[14] Cui Y,K?nig J,Leier I,et al. Hepatic Uptake of Bilirubin and Its Conjugates by the Human Organic Anion Transporter SLC21A6[J]. J Biol Chem,2001,276(13): 9626–9630.
[15] Ieiri I,Suzuki H,Kimura M,et al. Influence of common variants in the pharmacokinetic genes(OATP-C,UGT1A1,and MRP2) on serum bilirubin levels in healthy subjects[J].Hepatol Res ,2004,30(2):91-95.
(收稿日期:2014-09-24)
[5] Chung JY,Cho JY,Yu KS,et al. Effect of OATP1B1 (SLCO1B1) variant alleles on the Pharmacokinetics of pitavastatin in healthy volunteers[J]. Clin Pharmacol Ther,2005,78(4):342-350.
[6] Nishizato Y,I Ieiri,Suzuki H,et al. Polymorphisms of OATP-C (SLC21A6) and OAT3 (SLC22A8) genes: consequences for pravastatin pharmacokinetics[J]. Clin PHarmacol,Ther,2003,73(6):554-565.
[7] Zhang W,He YJ,Gan Z.et al. OATP1B1 polymorphism is a major determinant of serum bilirubin level but not associated with rifampicin-mediated bilirubin elevation[J]. Clin Exp Pharmacol Physiol ,2007,34(12):1240-1244.
[8] Furihata T1,Satoh N,Ohishi T,et al. Functional analysis of a mutation in the SLCO1B1 gene (c.1628T>G) identified in a Japanese patient with pravastatin-induced myopathy. Pharmacogenomics J[J]. 2009,9(3): 185-193
[9] Xu LY,He YJ,Zhang W,et al. Organic anion transporting polypeptide-1B1 haplotypes in Chinese patients[J]. Acta Pharmacol Sin,2007,28(10):1693-1697.
[10] Nies AT,Niemi M,Burk O,et al. Genetics is a major determinant of expression of the human hepatic uptake transporter OATP1B1,but not of OATP1B3 and OATP2B1[J].Genome Med ,2013,5 (1): 1.
[11] 熊玉卿、袁钊、温金华、等. OATP1B1 转运体的基因多态性与瑞舒伐他汀的关联[J]. 江西医药,2012,47(5):421-424.
[12] Gerloff T,Schaefer M,Mwinyi J,et al. Influence of the SLCO1B1*1b and *5 haplotypes on pravastatin's cholesterol lowering capabilities and basal sterol serum levels[J].Naunyn Schmiedebergs Arch Pharmacol,2006,373(1):45-50.
[13] Niemi M,Schaeffeler E,Lang T,et al. High plasma pravastatin concentrations are associated with single nucleotide polymorpHisms and haplotypes of organic anion transporting polypeptide-C (OATP-C,SLCO1B1)[J]. Pharmacogenetics,2004,14(7):429-440.
[14] Cui Y,K?nig J,Leier I,et al. Hepatic Uptake of Bilirubin and Its Conjugates by the Human Organic Anion Transporter SLC21A6[J]. J Biol Chem,2001,276(13): 9626–9630.
[15] Ieiri I,Suzuki H,Kimura M,et al. Influence of common variants in the pharmacokinetic genes(OATP-C,UGT1A1,and MRP2) on serum bilirubin levels in healthy subjects[J].Hepatol Res ,2004,30(2):91-95.
(收稿日期:2014-09-24)