对氧磷酯酶与动脉粥样硬化关系研究的新进展

对氧磷酯酶 (PON)是一类与HDL结合的酯酶 ,能水解有机磷。近年的研究表明它可抑制HDL和LDL的氧化 ,从而达到抗动脉粥样硬化的效果。PON的基因多态性、活性与它的抗动脉粥样硬化作用密切相关 ,并受体内外一些因素的调节     

Ⅱ型对氧磷酯酶基因与疾病

对氧磷酯酶（paraoxonase,PON)基因家族包含着至少三个成员，分别为PON1，PON2和PON3，它们都位于染色体7q21.3-q22.1,PON2和PON3基因是五年前通过遗传学的方法发现的，直到最近，有关PON基因产物和生理作用了解甚少，PON2基因产物在体内广泛分布，目前还没有关于生理作用机制的实验，临床研究表明其作用与某些物质代谢的定量分析相关，PON3基因产物主要在肝脏表达，体外实验提示其具有水妥芳香族丙酯的活性。但其体内的生理作用及与疾病的相关性尚无研究报道，进一步的研究应探讨关于PON基因家族变异与疾病的关系。临床检查的意义以及是否作为治疗干预的候选基因。     

对氧磷酶1与子痫前期关系的研究进展

对氧磷酶（paraoxonase，PON）是一类钙依赖性的芳香酯酶，在脂类代谢中具有重要的抗氧化活性可在对抗氧化应激导致的内皮功能受损方面发挥重要作用。当其活性下降时降低的抗氧化水平和升高的脂质过氧化产物可能导致对血管内皮的损坏并引起子痫前期临床症状的出现。     

对氧磷酶1 55 Met/Leu、对氧磷酶2 148 Ala/Gly基因多态性与冠状动脉粥样硬化性心脏病的关系

目的探讨对氧磷酶1 55Met/Leu(paraoxonase 1, PON1 55Met/Leu)、对氧磷酶2 148 Ala/Gly(PON2148 Ala/Gly)基因多态性与冠状动脉粥样硬化性心脏病(简称冠心病)、血浆对氧磷酶(paraoxonase,PON)、总超氧化物歧化酶(total superoxide dismutase, T-SOD)活性以及丙二醛(maleic dialdehyde, MDA)浓度的关系.方法采用聚合酶链反应-限制性片段长度多态性方法检测262例冠心病患者和100名对照的PON1 55Met/Leu、PON2 148 Ala/Gly基因多态性,采用比色法测定血浆PON、T-SOD活性以及MDA浓度.结果与对照比较,冠心病患者的血浆PON[(349.27±138.36) nmol/min· mL vs. (454.75±166.00) nmol/min*mL, P<0.01]、T-SOD[(23.61±16.51) U/mL vs. (44.01±22.68) U/mL, P<0.01]活性明显降低,MDA浓度显著增高[(2.47±0.73) nmol/mL vs. (2.15±0.55) nmol/mL, P<0.01];冠心病患者的PON1 55 LM杂合子基因型(24.8% vs. 1.4%, P<0.01)、M等位基因频率(12.4% vs. 0.5%,P=0.001),PON2148 GG纯合子基因型和AG 杂合子基因型(11.8% vs. 5.0%和48.1% vs. 24.0%, P<0.01)、G等位基因频率(36.0% vs. 17.0%, P<0.01)较对照组明显增高;PON1 55 LM杂合子基因型的PON和T-SOD活性较LL纯合子基因型明显降低(P<0.01和P<0.05);PON2148 GG基因型和AG基因型的PON活性较AA基因型明显降低(P<0.01);Logistic回归分析显示PON1 55 LM杂合子基因型、M等位基因、PON2 148GG/AG基因型、G等位基因是冠心病的危险因子.结论冠心病患者的血浆PON和T-SOD活性明显降低,MDA浓度显著增高;PON1 55Met/Leu的LM基因型和M等位基因、PON2148 Ala/Gly的GG/AG基因型和G等位基因是冠心病的危险因子,并且与其他基因型相比,这些基因型患者的血浆PON活性降低.     

对氧磷酯酶1基因多态性与Ⅱ型糖尿病合并冠心病

对氧磷酯酶 (PON)是一种钙离子依赖性芳香酯酶 ,通过 apo A I紧密结合于 HDL 颗粒上 ,水解脂质过氧化物 ,防止L DL、HDL 和 DNA被氧化修饰 ,破坏 ox- L DL 中的溶血磷脂 ,具有心血管保护作用。PON基因是一个由 PON1、PON2、PON3基因组成的多基因家族 ,研究表明 PON1基因多态性是 型糖尿病合并大血管并发症的独立危险因素 ,分别是启动子区多态性、5 5位 Met/ L eu多态性 (等位基因 M/ L)、192位 Gln/ Arg多态性 (等位基因 A/ B)。     

对氧磷酶2基因C311S多态性与2型糖尿病合并缺血性脑卒中的相关性

目的 探讨对氧磷酶2(paraoxonase 2，PON2)基因多态性与2型糖尿病(type 2 diabetes mellitus，T2DM)患者合并缺血性脑卒中(ischemic stroke，IS)的关系。方法 用聚合酶链反应—限制性片段长度多态性分析法探查PON2基因C311S多态性在T2DM合并IS组、T2DM无IS组以及正常对照组的基因频率。结果 发现中国人存在PON2基因C311S多态性，C／S等位基因频率为0．145／0．855。T2DM合并IS组患者PON2基因的C等位基因频率显著高于T2DM无IS组和正常对照组，差异有显著性(P＜0．05)。结论 中国人2型糖尿病患者PON2基因第311位密码子的多态性与并发缺血性脑卒中有关，C等位基因是2型糖尿病并发缺血性脑卒中的危险因素之一。     

Ⅱ型对氧磷酯酶基因与疾病

对氧磷酯酶 (paraoxonase,PON)基因家族包含着至少三个成员 ,分别为 PON1、PON2和 PON3,它们都位于染色体7q2 1.3- q2 2 .1。PON2和 PON3基因是五年前通过遗传学的方法发现的。直到最近 ,有关 PON基因产物和生理作用了解甚少。PON2基因产物在体内广泛分布 ,目前还没有关于生理作用机制的实验 ,临床研究表明其作用与某些物质代谢的定量分析相关。PON3基因产物主要在肝脏表达 ,体外实验提示其具有水解芳香族丙酯的活性 ,但其体内的生理作用及与疾病的相关性尚无研究报道。进一步的研究应探讨关于 PON基因家族变异与疾病的关系、临床检查的意义以及是否作为治疗干预的候选基因     

对氧磷酯酶1基因多态性与Ⅱ型糖尿病合并冠心病

对氧磷酯酶(PON)是一种钙离子依赖性芳香酯酶，通过apoA Ⅱ紧密结合于HDL颗粒上，水解脂质过氧化物，防止LDL、HDL和DNA被氧化修饰，破坏ox—LDL中的溶血磷脂，具有心血管保护作用。PON基因是一个由PONl、PON2、PON3基因组成的多基因家族，研究表明PONl基因多态性Ⅱ型糖尿病合并大血管并发症的独立危险因素，分别是启动子区多态性、55位Met／Leu多态性(等位基因M/L)、192位Gln／Arg多态性(等位基因A／B)。     

大鼠对氧磷酶1真核表达载体的构建及在体外的表达

目的构建大鼠对氧磷酶1(paraoxonase1,PON1)真核表达载体,并检测其在体外培养细胞中的表达及功能,为进一步探索运用其进行基因防治肺部感染奠定基础。方法利用RT-PCR扩增大鼠PON1编码区全长序列,克隆入pcDNA3.1( ),鉴定无误后,脂质体转染A549细胞及293细胞,Western印迹检测蛋白表达,并检测其芳香酯酶活性及对铜绿假单胞菌密度感知系统信号分子N-酰基高丝氨酸内酯(N-acylhomoserine lactones,AHLs)的水解功能。结果分别从大鼠肝组织中扩增出1153bp片段,克隆入表达载体后进行酶切鉴定和测序结果正确。转染细胞后能够表达目的蛋白,该蛋白具有芳香酯酶和AHLs内酯酶活性。结论成功构建了含有大鼠PON1真核表达载体,质粒能够在真核细胞中表达,能够有效地水解铜绿假单胞菌密度感知系统信号分子。     

对氧磷酶-3和糖氧化载脂蛋白A-I与糖尿病并发冠心病的关系

目的:探讨血清对氧磷酶-3(PON3)和载脂蛋白A-I(apoA-I)糖氧化水平与2型糖尿病(T2DM)并发冠心病(CAD)及其严重程度的关系。方法:202例T2DM患者按其是否合并CAD分为单纯糖尿病组(DM组,n=60)和T2DM合并CAD组(DM并CAD组,n=142),后者进一步按病变累及冠脉支数分为1支病变组(n=40),2支病变组(n=52)和3支病变组(n=50)。另选62例健康受试者为对照组。采用ELISA测定各组血清PON3水平;超速离心全血获得高密度脂蛋白(HDL),采用SDS-PAGE电泳分离apoA-I,免疫印迹分析apoA-I糖氧化水平。分析PON3水平和apoA-I糖氧化水平与冠脉病变程度的相关性。结果:DM并CAD组和3支病变组血清PON3水平(1.52±1.14ng/ml、1.31±1.09ng/ml)分别显著低于DM组(1.98±1.04ng/ml,P0.05)、对照组(2.46±1.01ng/ml,P0.05)和1支病变组(1.74±1.19ng/ml,P0.05)。apoA-I糖氧化水平是CAD及其病变严重程度的独立预测因子,并与冠脉病变严重程度指数、病变冠脉支数呈显著正相关(r分别为0.611、0.549,P均0.01)PON3水平与apoA-I糖氧化水平呈负相关(r=-0.388,P0.01),且两者均为CAD独立预测因素。结论:低PON3水平与apoA-I糖氧化水平相关,后者与T2DM患者并发CAD及其严重程度相关。     

小鼠骨骼肌电转移hPDN1Q基因可以减轻CCl_4诱导的急性肝损伤

目的研究人Q型对氧磷酶1(human paraoxonase 1 Q,hPON1Q)转基因表达对小鼠四氯化碳(carbon tetrachloride,CCl_4)诱导急性肝损伤的缓解效果,为防治肝脏疾病寻找新的途径。方法小鼠骨骼肌直接注射含hPON1Q的真核表达质粒裸DNA并用电刺激介导表达,测量血清芳香酯酶的活性变化显示hPON1Q转基因表达效果,并使用血清谷丙转氨酶(ALT)、谷草转氨酶(AST)为指标及肝组织病理切片检测肝损伤的程度。结果hPON1Q转基因表达小鼠血清中芳香酯酶活性提高约50%,并可持续到16d以后。使用PON1裸DNA电刺激治疗组比对照组小鼠在用CCl_4诱导24h后血清芳香酯酶活性高60%,两种血清转氨酶指标及肝组织切片的病理学分析表明肝脏损伤程度有明显的减轻。结论电刺激介导的重组人PON1Q基因裸DNA在小鼠体内的表达对CCl_4诱导的肝损伤具有显著的防护作用。     

FXR基因家族

FXR基因家族是与脆性X综合征发病相关的一个基因家族。有三个家族成员。在进化上高度保守,氨基酸序列高度相似,有共同的功能结构域：两个KH结构域,RGG盒,NES和NLS。能够与RNA和多聚核蛋白体结合。通过NES和NLS携带其mRNA在细胞核和细胞质之间穿梭。不同的蛋白亚型其组织分布各异。该家族成员在大脑和神经发育过程中发挥重要作用,影响认知过程和智力发育。     

Serum Cystatin C Is a Determinant of Paraoxonase Activity in Hemodialyzed and Renal Transplanted Patients

Background: Human paraoxonase-1 (PON1) inhibits LDL-oxidation and atherogenesis, and possesses lactonase activity. Decreased PON1 activity was found in hemodialyzed and renal transplanted patients. Cystatin C plays a protective role in atherosclerosis, and is a new, sensitive marker of renal function. The relationship between these two markers in renal failure has not been investigated.Aims: The goal of this study was to clarify the relationship between PON1 activity, cystatin C and homocysteine in chronic renal failure. We also determined the levels of oxidatively modified LDL (oxLDL) and thiobarbituric acid reactive substances (TBARS) to characterize lipid peroxidation.Patients and methods: 74 hemodialized (HD), 171 renal transplanted patients (TRX), and 110 healthy controls (C) were involved in the study. PON1 activity and TBARS levels were measured spectrophotometrically. OxLDL level was determined with sandwich ELISA.Results: There was a negative correlation between PON1 activity and cystatin C level. Homocysteine level correlated negatively with PON1 activity, and positively with cystatin C level. OxLDL and TBARS levels were significantly higher in the HD and TRX groups compared to C.Conclusions: Cystatin C may be a good predictive factor not only for homocysteine levels but for the antioxidant status in patients with renal failure and renal transplantation.     

人芳香二烷基磷酸酯酶基因丛基因多态性快速分析法

目的建立一种人芳香二烷基磷酸酯酶（PON）基因丛等位基因快速分型法。方法在Multiplex-PCR-RELP基础上，通过引物设计错配，在一体系中同时扩增分别含PON1-192、PON1-55和PON2-31l位密码子的DNA片段，当等位基因为PON1-192R／PON1-55L／PON2-31lS时，PCR扩增产物中均被引入唯一的限制性内切酶HinfⅠ的识别位点G^＋ANTC。PCR扩增产物经酶消化，聚丙烯酰胺凝胶电泳后，相互分开的不同组合的片段，确认为不同的基因型组合，同时对3个位点进行基因分型。结果在检测的80例健康个体中，等位基因频率为PON1-192：Q46．9％．R53．1％：PON1-55：L95．6％，M4．4％；PON2-31l：S78．8％，C21．2％。结论此方法快速分析3个位点的基因多态性，省时省力、节约经费，便于3个位点之间的连锁分析，具有推广价值。     

Paraoxonase Gene Polymorphism in South-western Korean Population

Paraoxonase (PON) has anti-atherogenic activity. Considering the important role of polymorphism in the genetic susceptibility to cardiovascular disease and the variability of its allele frequencies in different ethnic groups, the distribution of genotypes and allele frequencies of PON1M55L, PON1Q192R, PON2A148G, and PON2S311C polymorphisms was analyzed in a total 988 South-western Koreans and determined their effects on lipid parameters. The genotype distribution of PON1 at position 55 was LL=0.886, LM=0.114; and at position 192 was QQ=0.406, QR=0.594. The frequencies of the PON1 55L allele and the PON1 192R allele were similar to those seen in Chinese populations and Western populations, respectively. The genetic distribution of PON2 at position 148 was AA=0.619, AG=0.345, GG=0.035; and at position 311 was CC=0.035, SC=0.345, SS=0.619. The frequencies of the PON2 148G and 311S alleles were similar to those seen in Chinese populations. The concentrations of LDL and ApoB were significantly different between the PON2A148G (P<0.05) and PON2 S311C polymorphisms (P<0.01). PON polymorphisms and allele frequencies were described in Koreans living south-western part of Korea. These ethnic variations are considered important in the interpretation of diseases associated with PON polymorphisms.     

中国汉族人芳香二烷基磷酸酯酶基因启动子多态性与冠心病的关系

芳香二烷基磷酸酯酶（paraoxonase,PON1)基因启动子区－108（C／T）多态性与人类冠心病（CHD）及其血脂水平的关系。采用多聚酶链反应－限制性长段多态性的分析方法（PCR－RFLP）检测CHD患者PON1基因启动子区－108位点的多态性。结果显示PON1启动子区－108位点存在多态性，出现三种基因型：TT，TC和CC。各等位基因的分布在正常对照组及CHD组之间存在显著性差异，且CC基因型的分布在两组间也有显著差异（P＜0．05）。正常对照组与CHD组间各基因型血浆Apo AI水平无显著性差异；CHD组CC纯合子的血浆高密度脂蛋白胆固醇（HDL－C）水平明显低于对照组（P＜0．05），而两组间TT纯合子和TC杂合子的HDL－C水平无统计学差异。说明该多态性可能与CHD有一定的相关性。     

Association of paraoxonase activity and atherosclerosis in patients with chronic hepatitis B

Background

The hepatitis B virus is a significant pathogen that causes cirrhosis, and hepatocellular cancer as a result of the damage it causes to liver cells. Its infection affects more than 400 million people globally. Although there is an effective vaccine and treatment methods, almost 1, 000, 000 people die every year.

Objective

To investigate paraoxonase and arylesterase activities along with oxidative status parameters and serum lipid levels, and to find out if there is any increased susceptibility to atherogenesis.

Methods

Thirty-four subjects with chronic hepatitis B and 39 healthy subjects as control were enrolled in the study. Age, body mass index and gender, Serum Triglycerides (TG), High-density Lipoprotein (HDL) and Low-Density lipoprotein (LDL) levels, serum paraoxonase-1 and arylesterase activities were determined. Oxidative and antioxidative statuses were evaluated by measuring serum-free sulfhydryl groups, lipid hydroperoxide levels, total antioxidant capacity, total oxidant status, and oxidative stress index.

Results

Serum TG and LDL levels were higher while serum HDL levels were lower in patients with chronic hepatitis B than in controls but the differences did not reach statistical significance. Serum paraoxonase-1 and arylesterase activities, plasma free sulfhydryl groups, and total antioxidant capacity were significantly lower in patients than in controls (p=0.018, p=0.005, p<0.001, p=0.037 respectively), while lipid hydroperoxide, total oxidant status, and oxidative stress index were significantly higher (for all p<0.001).

Conclusion

The diminution in the paraoxonase-1 and arylesterase activities could contribute to the accelerated development of atherosclerosis in patients with chronic hepatitis B.