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     

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。     

PON2基因C311S、G148A多态性与脑卒中关系的研究

目的探讨对氧磷酶2（paraoxonase2,PON2）基因多态性与脑卒中的关系。方法用聚合酶链反应-限制性片段长度多态性分析法分别检测PON2基因C311S、G148A多态性在脑出血组（150例）、脑梗死组（180例）和正常对照组（120名）的基因频率。结果发现中国湖南地区人群存在PON2基因C311S、G148A多态性,在正常对照组中等位基因频率分别是S/C0.77/0.23,A/G0.43/0.57。脑出血组、脑梗死组患者PON2基因的等位基因频率与正常对照组相比差异无统计学意义（P〉0.05）。结论PON2基因多态性可能与中国湖南汉族人群脑卒中发病无关,C/S、G/A等位基因可能不是中国湖南地区汉族人群脑卒中发病的独立危险因素。     

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)。     

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。     

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     

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。     

Genetic Variation in the Paraoxonase-3 (PON3) Gene is Associated with Serum PON1 Activity

Low serum paraoxonase1 (PON1) activity determined by paraoxon substrate is associated with coronary heart disease (CHD), diabetes and systemic lupus erythematosus (SLE) risk. In this investigation, we have examined the role of genetic variation in the PON3 gene in relation to PON1 activity and SLE risk in a biracial sample comprising 377 SLE patients and 482 controls from US whites and blacks. We genotyped six PON3 tagging single nucleotide polymorphisms (tagSNPs) and examined their associations with PON1 activity, SLE risk, antiphopholipid autoantibodies (APA), lupus nephritis, carotid vascular disease, and inflammation. With the exception of PON1 activity, no other significant associations were found with PON3 SNPs. Multiple regression analysis including all six PON3 tagSNPs and PON1/Q192R and L55M SNPs revealed significant association of PON1 activity with 4 SNPs: PON3/A10340C (p < 0.0001), PON3/A2115T (p = 0.002), PON1/L55M (p < 0.0001) and PON1/Q192R (p < 0.0001). These four SNPs explained 2%, 1%, 8% and 19% of the variation in PON1 activity, respectively. In summary, our new data indicate that genetic variation in the PON3 gene influences serum PON1 activity independently of the known effect of PON1 genetic variation. To our knowledge, this is the first study reporting the association of the PON3 gene variants with PON1 activity.     

Serum paraoxonase activity is associated with variants in the PON gene cluster and risk of Alzheimer disease

Previous studies have shown association of single nucleotide polymorphisms (SNPs) in 3 contiguous genes (PON1, PON2, and PON3) encoding paraoxonase with risk of Alzheimer disease (AD). We evaluated the association of serum paraoxonase activity measured by phenyl acetate (PA) and thiobutyl butyrolactone (TBBL) with risk of AD and with 26 SNPs spanning the PON gene cluster in 266 AD cases and 306 sibling controls from the MIRAGE study. The odds of AD (adjusted for age, gender, and ethnicity) increased 20% for each standard deviation decrease in PA or TBBL activity. There were association signals with activity in all 3 genes. Haplotypes including SNPs spanning the PON genes were generally more significant than haplotypes comprising SNPs from 1 gene. Significant interactions were observed between SNP pairs located across the PON cluster with either serum activity measure as the outcome, and between several PON SNPs and PA activity with AD status as the outcome. Our results suggest that low serum paraoxonase activity is a risk factor for AD. Furthermore, multiple variants in PON influence serum paraoxonase activity and their effects may be synergistic.     

Paraoxonase2 C311S polymorphism and low levels of HDL contribute to a higher mortality risk after acute myocardial infarction in elderly patients

It is well known that oxidative stress plays an important role in atherosclerosis and age-related diseases. The antioxidant properties of the Human Paraoxonase gene family (PON1, 2, 3) have been widely investigated, as well as a possible role of the such gene family in cardiovascular disease. In this study, we investigated the relationship between the C311S PON2 polymorphism and the prognosis of acute myocardial infarction (AMI). We analyzed the PON2 C311S polymorphism in 442 elderly patients who had experienced an AMI. PON2 C311S genotypes were identified by PCR based analysis and analyzed as C− (SS genotype) or C+ (CS + CC) carriers. After 1 year of follow-up, the cardiovascular mortality rate in a sub-group of 295 AMI patients was calculated. We found that AMI patients carrying CS + CC genotypes (C+ carriers) had a history of type 2 diabetes mellitus, low levels of HDL-cholesterol and higher levels of TroponinT (TnT). Furthermore, we found that C+ carrier patients with low levels of HDL-cholesterol had an increased risk for mortality after 1 year of follow-up (Log Rank = 11.45, p = 0.001). Our study suggests a possible role for PON2 C311S polymorphism in the pathogenesis of cardiac ischemic damage. Patients with at least one C allele (C+ carriers) represent a category of subjects at a higher risk for the development of AMI with a worse prognosis. Our findings suggest the need for a more careful clinical monitoring in older persons with such characteristics.     

Intervention with environmental enrichment after experimental brain trauma enhances cognitive recovery in male but not female rats

An increasing amount of evidence suggests a possible implication of oxidative stress in the pathophysiology of schizophrenia. Oxidized low-density lipoproteins (oxLDL) have been reported to be capable of eliciting neurocytotoxicity. On the other hand, paraoxonase (PON1), an arylesterase, plays a role in protection against oxidative modifications of LDL and is considered to be one of the antioxidant enzymes. Thus, we investigated the genetic association between a functional polymorphism (Gln192Arg) of the human PON1 gene and schizophrenia in 244 patients and 177 controls. No significant association between the polymorphism and schizophrenia was observed. In addition, our results revealed that there was no association between the genotypes of the polymorphism and any demographic characteristics of patients such as gender, age, age at onset, or current neuroleptic dosage. Our results suggest that the Gln192Arg polymorphism of the PON1 gene may not be involved in the susceptibility to schizophrenia.     

The human paraoxonase gene cluster as a target in the treatment of atherosclerosis

The paraoxonase (PON) gene cluster contains three adjacent gene members, PON1, PON2, and PON3. Originating from the same fungus lactonase precursor, all of the three PON genes share high sequence identity and a similar β propeller protein structure. PON1 and PON3 are primarily expressed in the liver and secreted into the serum upon expression, whereas PON2 is ubiquitously expressed and remains inside the cell. Each PON member has high catalytic activity toward corresponding artificial organophosphate, and all exhibit activities to lactones. Therefore, all three members of the family are regarded as lactonases. Under physiological conditions, they act to degrade metabolites of polyunsaturated fatty acids and homocysteine (Hcy) thiolactone, among other compounds. By detoxifying both oxidized low-density lipoprotein and Hcy thiolactone, PONs protect against atherosclerosis and coronary artery diseases, as has been illustrated by many types of in vitro and in vivo experimental evidence. Clinical observations focusing on gene polymorphisms also indicate that PON1, PON2, and PON3 are protective against coronary artery disease. Many other conditions, such as diabetes, metabolic syndrome, and aging, have been shown to relate to PONs. The abundance and/or activity of PONs can be regulated by lipoproteins and their metabolites, biological macromolecules, pharmacological treatments, dietary factors, and lifestyle. In conclusion, both previous results and ongoing studies provide evidence, making the PON cluster a prospective target for the treatment of atherosclerosis.     

Association of a protective paraoxonase 1 (PON1) polymorphism in Parkinson's disease

Pesticide exposure has been suggested to increase the risk to develop Parkinson's disease (PD). The arylesterase paraoxonase 1 (PON1) is mainly expressed in the liver and hydrolyzes organophosphates such as pesticides. The polymorphism Leu54Met (rs854560) in PON1, impairing enzyme activity and leading to decreased PON1 expression levels, has been reported to be associated with Parkinson's disease (PD). PON1 is part of a cluster on chromosome 7q21.3 together with PON2 and PON3. We investigated the occurrence of four additional polymorphisms in PON1 and two in PON2 in a Swedish PD case–control material. We found a significant association (p = 0.007) with a PON1 promoter polymorphism, rs854571. The minor allele was more common among controls than PD cases which suggest a protective effect. This is strengthened by the fact that rs854571 is in strong linkage disequilibrium with another PON1 promoter polymorphism, rs854572, reported to increase PON1 gene expression. Our findings support the hypothesis that PON1 is involved in the etiology of PD and that higher PON1 levels are reducing the risk for PD.     

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.     

Atherosclerosis and antiphospholipid syndrome

Atherosclerosis is an autoimmune/inflammatory disease associated with infectious, inflammatory, and autoimmune factors. Both humoral and cellular immune mechanisms have been proposed to participate in the onset and/or progression of atheromatous lesions. Heat-shock protein (hsp), oxidized low-density lipoprotein (LDL), and β2-GPI have been reported to elicit humoral and cellular immune response in both experimental animals and humans. These autoantigens are expressed within atherosclerotic lesions. Immunization with the given autoantigens elicits an immune response that influences lesion progression. Atherosclerosis susceptibility can be transferred by autoantigen-sensitized lymphocytes from immunized animals. Patients with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) have a high risk for atherosclerotic cardiovascular events. The traditional risk factors fail to fully account for accelerated atherosclerosis in SLE and APS. Immunological alterations, such as antibodies to oxidized LDL, antiphospholipid antibodies (aPL), antibodies to β-2 Glycoprotein (anti-β2-GPL), anti-prothrombin antibodies, may play a role in premature atherosclerosis in SLE and APS. Paraoxonase (PON1) is an enzyme with antioxidant activity attached to the circulating high-density lipoprotein (HDL) in plasma. Its function is to prevent oxidation of LDL, thereby accounting for the antioxidant properties and the atherosclerotic protective effects of HDL. The relationship between PON1 and aPL has been recently suggested. IgG anti-HDL and IgG anti-β2-GPI antibodies were associated with reduced PON1 activity in patients with SLE and primary APS. The determination of classic and new factors, together with specific autoantibody titers and the use of Doppler carotid ultrasound, are useful methods to detect early atherosclerosis in SLE and PAPS. Therapeutic strategies, including early control of disease and other risk factors, are essential to reduce morbidity and mortality.     

Gender differences in the association of gene polymorphisms with type 2 diabetes mellitus

Type 2 diabetes mellitus is a complex metabolic disorder in which endogenous sex hormones may contribute to sex-dependent etiologies. We hypothesized that genetic variants related to type 2 diabetes mellitus might differ between men and women. We thus performed a large-scale association study to identify gene polymorphisms associated with type 2 diabetes mellitus in men and women separately. The study population comprised 4854 unrelated Japanese individuals (2688 men, 2166 women), including 1490 subjects with type 2 diabetes mellitus (969 men, 521 women). The genotypes for 16 gene polymorphisms were determined with a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. Multivariable logistic regression analysis with adjustment for age, body mass index, and smoking status revealed that the T-->G (3' UTR) polymorphism of the thrombospondin 2 gene (THBS2), the -603A-->G polymorphism of the coagulation factor III gene (F3), and the G-->T (intron 2) polymorphism of the adipocyte, C1Q, and collagen domain containing (adiponectin) gene (ADIPOQ) were significantly associated with the prevalence of type 2 diabetes mellitus in men, and that the A-->G (Arg160Gly) polymorphism of the paraoxonase 1 gene (PON1) was significantly associated with this condition in women. A stepwise forward selection procedure demonstrated that genotypes of THBS2, F3, and ADIPOQ were significant determinants of type 2 diabetes mellitus in men, and that genotype of PON1 significantly affected this condition in women. Genotyping of these polymorphisms may prove informative for assessment of the genetic component of type 2 diabetes mellitus for men and women separately.     

Effects of estrogen-only therapy on LDL oxidation in women with hysterectomy: Does paraoxonase genotype play a role?

OBJECTIVES: This study investigated the effects of estrogen-only therapy on lipid profile (through susceptibility of low density lipoproteins to oxidation) and on oxidant-antioxidant parameters in surgical menopausal women. PON genotypes are also evaluated considering that they may be associated with the personal differences observed in antioxidant effects induced by estrogen. METHODS: Thirty women who had undergone hysterectomy+bilateral ovariectomy in the last 3 years, with causes other than malignancy were included and given estrogen-only (Premarin-Wyeth Inc. 0.625 mg/day/6 months, equine conjugated estrogen). Blood samples were collected at baseline, first and sixth month of treatment. Serum (total antioxidant activity-TAO and PON activity), erythrocyte (TBARS and catalase activity), LDL and Cu2+ induced ox-LDL (TBARS and diene levels) samples were evaluated and PON1 192 polymorphisms were determined by PCR amplification & restriction enzyme digestion. RESULTS: At the sixth month, a higher TAO activity (p=0.016) and a lower eTBARS (p=0.028) were detected compared to the basal values. LDL and Cu induced ox-LDL TBARS levels at the sixth month of treatment were significantly (p=0.012 and 0.026, respectively) lower compared to the pretreatment values. Baseline eTBARS (p=0.007), LDL TBARS (p=0.044) and eCAT (p=0.033) activities were significantly higher in homozygote Q allele carriers compared to subjects with R allele. LDL TBARS and Cu2+ induced ox-LDLTBARS of QQ subjects (p=0.018 and 0.050) as well as LDL TBARS of QR subjects (p=0.044) showed a significant decrease with estrogen-only treatment. CONCLUSIONS: Our study drives the attention to PON polymorphism in postmenopausal women who have risk for atherosclerosis. Although our data is limited, this study is the first that focuses on the role of PON genotypes in antiatherosclerotic effects of estrogen-only and provides important points for further studies.