Is it just paraoxonase 1 or are other members of the paraoxonase gene family implicated in atherosclerosis?

C. spinosa L. subsp. rupestris Phytochemical Profile and Effect on Oxidative Stress in Normal and Cancer Cells

Spices, widely used to improve the sensory characteristics of food, contain several bioactive compounds as well, including polyphenols, carotenoids, and glucosynolates. Acting through multiple pathways, these bioactive molecules affect a wide variety of cellular processes involved in molecular mechanisms important in the onset and progress of human diseases. Capparis spinosa L. is an aromatic plant characteristic of the Mediterranean diet. Previous studies have reported that different parts (aerial parts, roots, and seeds) of C. spinosa exert various pharmacological activities. Flower buds of C. spinosa contain several bioactive compounds, including polyphenols and glucosinolates. Two different subspecies of C. spinosa L., namely, C. spinosa L. subsp. spinosa, and C. spinosa L. subsp. rupestris, have been reported. Few studies have been carried out in C. spinosa L. subsp. rupestris. The aim of our study was to investigate the phytochemical profile of floral buds of the less investigated species C. spinosa subsp. rupestris. Moreover, we investigated the effect of the extract from buds of C. spinosa subsp. rupestris (CSE) on cell proliferation, intracellular ROS levels, and expression of the antioxidant and anti-apoptotic enzyme paraoxonase-2 (PON2) in normal and cancer cells. T24 cells and Caco-2 cells were selected as models of advanced-stage human bladder cancer and human colorectal adenocarcinoma, respectively. The immortalized human urothelial cell line (UROtsa) and human dermal fibroblast (HuDe) were chosen as normal cell models. Through an untargeted metabolomic approach based on ultra-high-performance liquid chromatography quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS), our results demonstrate that C. spinosa subsp. rupestris flower buds contain polyphenols and glucosinolates able to exert a higher cytotoxic effect and higher intracellular reactive oxygen species (ROS) production in cancer cells compared to normal cells. Moreover, upregulation of the expression of the enzyme PON2 was observed in cancer cells. In conclusion, our data demonstrate that normal and cancer cells are differentially sensitive to CSE, which has different effects on PON2 gene expression as well. The overexpression of PON2 in T24 cells treated with CSE could represent a mechanism by which tumor cells protect themselves from the apoptotic process induced by glucosinolates and polyphenols.

Effect of Carotenoids on Paraoxonase-1 Activity and Gene Expression

Paraoxonase 1 (PON1) is an antioxidant enzyme attached to HDL with an anti-atherogenic potential. It protects LDL and HDL from lipid peroxidation. The enzyme is sensitive to various modulating factors, such as genetic polymorphisms as well as pharmacological, dietary (including carotenoids), and lifestyle interventions. Carotenoids are nutritional pigments with antioxidant activity. The aim of this review was to gather evidence on their effect on the modulation of PON1 activity and gene expression. Carotenoids administered as naturally occurring nutritional mixtures may present a synergistic beneficial effect on PON1 status. The effect of carotenoids on the enzyme depends on age, ethnicity, gender, diet, and PON1 genetic variation. Carotenoids, especially astaxanthin, β-carotene, and lycopene, increase PON1 activity. This effect may be explained by their ability to quench singlet oxygen and scavenge free radicals. β-carotene and lycopene were additionally shown to upregulate PON1 gene expression. The putative mechanisms of such regulation involve PON1 CpG-rich region methylation, Ca(2+)/calmodulin-dependent kinase II (CaMKKII) pathway induction, and upregulation via steroid regulatory element-binding protein-2 (SREBP-2). More detailed and extensive research on the mechanisms of PON1 modulation by carotenoids may lead to the development of new targeted therapies for cardiovascular diseases.

Epigenetics of paraoxonases

PURPOSE OF REVIEW

Studies have shown the three-member paraoxonase (PON) multigene family to be involved in the development of a large variety of diseases with an inflammatory component. Environmental factors such as lifestyle-related factors differ widely between populations and it is important to consider that their impacts may be exerted through the epigenetic mechanisms, which connect genes, the environment and disease development and are a potential therapeutic avenue.

RECENT FINDINGS

In the review period, very little was published on epigenetics of PON2 or PON3, mostly on their diagnostic value in cancer by measuring methylation levels of these genes. However, the picture is more promising with PON1. Here, several studies have linked the epigenetic regulation of PON1 to various metabolic processes and particularly to the development of several diseases, including stroke, heart disease, aortic valve stenosis and chronic obstructive pulmonary disease.

SUMMARY

Studies into the epigenetic regulation of the PON family are in their infancy. However, recent studies linking epigenetic regulation of PON1 to disease development will encourage further research and open up the possibility for new potential therapeutic interventions.

Low Serum Paraoxonase-1 Activity Associates with Incident Cardiovascular Disease Risk in Subjects with Concurrently High Levels of High-Density Lipoprotein Cholesterol and C-Reactive Protein

Paroxonase-1 (PON1) is a key enzyme that inhibits low-density lipoprotein oxidation and consequently atherogenesis. Here, we assessed whether low serum PON1 activity associates with incident cardiovascular disease (CVD) in subjects with high levels of high-density cholesterol (HDL-C) and C-reactive protein (CRP), a marker of low-grade systemic inflammation. Cox proportional-hazards modeling of incident CVD risk (11 years mean follow-up) adjusted for relevant clinical and biomarker covariates was performed on a population-based study (N = 7766) stratified into three groups: low CRP-(LR; event rate 4.9%); low HDL-C/high CRP-(HR1; event rate 14.4%); and high HDL-C/high CRP-(HR2; event rate 7.6%). Modeling results for PON1 activity in HR2 were significant and robust (hazard ratio/SD unit-0.68, 95% CI 0.55-0.83, p = 0.0003), but not so for LR and HR1. Analyses in HR2 of the interaction of PON1 with HDL-C, apoA-I, apoA-II, and apoE levels were significant only for PON1 with apoE (hazard ratio-1.77, 95% CI 1.29-2.41, p = 0.0003). Subsequent subgroup analysis revealed inverse risk dependence for apoE at low PON1 levels. In conclusion, in a population-based study of subjects with concurrently high HDL-C and CRP levels, low serum PON1 activity associates with incident CVD risk with risk accentuated at low apoE levels.

Expression levels of paraoxonase-1 in aortic valve tissue are associated with the progression of calcific aortic valve stenosis

Background

Paraoxonase-1 (PON1) participates in several vital steps of lipid metabolism, which is associated with calcific aortic valve stenosis (CAVS). Although a few studies have suggested that PON1 in blood could inhibit aortic valve calcification, they did not provide detailed descriptions. In this study, we hypothesized that PON1 is expressed in the aortic valve and that the PON1 level is related to the severity of CAVS.

Methods

A total of 118 consecutive patients with CAVS were enrolled in the study; 35 individuals without aortic valve calcification were included in the control group. Aortic valve tissue was obtained from postoperative pathologic specimens. PON1 was detected qualitatively using immunohistochemistry and quantitatively using an enzyme-linked immunosorbent assay. The severity of aortic stenosis was evaluated using echocardiography.

Results

We detected PON1 in the aortic valve and noticed that the PON1 level was significantly lower in the case group than in the control group (P<0.001). Furthermore, we found no significant difference between the mild and moderate stenosis groups (P=0.395). However, the PON1 levels were obviously higher in both the mild and moderate stenosis groups than in the severe stenosis group (both P<0.001). We also detected a significant negative correlation between PON1 level and the maximum aortic valve gradient in the case group.

Conclusions

We detected PON1 in the aortic valve for the first time, and our results suggest that the PON1 level in aortic valve tissue decreases with increasing severity of aortic valve stenosis.

Ameliorative effects of bone marrow derived pancreatic progenitor cells on hyperglycemia and oxidative stress in diabetic rats

The present study aimed to investigate the effects of Bone marrow derived pancreatic progenitor cells (BM- PPCs) in diabetic rats. It was conducted on 30 adult male Sprague-Dawley rats weighing 200-220 g. They were divided into three groups: (a) Group 1 was the control group; (b) Group 2 was the diabetic (induced diabetic by a single intraperitoneal (IP) injection of streptozotocin (STZ) (60 mg/kg) and (c) Group 3 was the treated (received injection of 2.5 X 10⁶ BM- PPCs via the tail vein twice with a 21-day time interval). The blood glucose level was estimated weekly, the oxidative stress and insulin gene expression were evaluated at the end of the experiment. Pancreatic tissue histopathology was performed. The insulin immuno-histochemical reaction was applied to the islets. The blood glucose level was reduced in the treated group over time till reaching its acceptable level whereas it was increased in the diabetic group. The oxidative stress was decreased in the treated group compared to the diabetic one. The treated group showed increased expression of the insulin gene compared to the diabetic group. The immune-histochemical analysis of insulin showed an increased number and size of pancreatic islets in the treated group compared to the diabetic one. Thus, the twofold injection of BM- PPCs could restore the normal beta-cell morphology and function.

Paraoxonase 2 overexpression inhibits tumor development in a mouse model of ovarian cancer

Ovarian cancer (OC) is most lethal malignancy among all gynecological cancer. Large bodies of evidences suggest that mitochondrial-derived ROS play a critical role in the development and progression of OC. Paraoxonase 2 (PON2) is a membrane-associated lactonase with anti-oxidant properties. PON2 deficiency aggravates mitochondrial ROS formation, systemic inflammation, and atherosclerosis. The role of PON2 in cancer development remains unknown. In this report, in human, we identified that PON2 expression is higher in early stages (but not in late stages) of OC when compared to normal tissue. Using a mouse xenograft model of OC, we demonstrate that overexpression of PON2 prevents tumor formation. Mechanistically, PON2 decreases OC cell proliferation by inhibiting insulin like growth factor-1 (IGF-1) expression and signaling. Intriguingly, PON2 reduces c-Jun-mediated transcriptional activation of IGF-1 gene by decreasing mitochondrial superoxide generation. In addition, PON2 impairs insulin like growth factor-1 receptor (IGF-1R) signaling in OC cells by altering cholesterol homeostasis, which resulted in reduced caveolin-1/IGF-1R interaction and IGF-1R phosphorylation. Taken together, we report for the first time that PON2 acts as a tumor suppressor in the early stage of OC by reducing IGF-1 production and its signaling, indicating PON2 activation might be a fruitful strategy to inhibit early stage ovarian tumor.

A non-synonymous single nucleotide polymorphism in the paraoxonase 3 gene regulates meat quality in Berkshire pigs

The paraoxonase (Pon) gene family contains three members: Pon1, Pon2, and Pon3. Pon3 modulates superoxide production and prevents apoptosis. The role of Pon3 has not been fully elucidated in the pig. This study is the first to investigate the association between Pon3 and meat quality in the Berkshire pig. We identified a single nucleotide polymorphism in the Pon3 gene (c.227A > G) that resulted in a change in histidine to arginine at position 76. To elucidate the role of this non-synonymous single nucleotide polymorphism in the Pon3 gene, we analysed the Pon3 genotype and meat quality traits in 434 Berkshire pigs. The results of a codominant model show that carcass weight, meat colour (lightness), cooking loss, and the Warner–Bratzler shear force were significantly associated with the Pon3 genotype. Furthermore, the 24-h post-mortem pH had the strongest relationship with the Pon3 genotype. The G allele decreased cooking loss and fat content, whereas the A allele increased the 24-h post-mortem pH and decreased backfat thickness, which contribute to meat storage life and M. longissimus dorsi depth respectively. In conclusion, the non-synonymous single nucleotide polymorphism in the Pon3 gene showed a close correlation with meat quality traits in the Berkshire pig.

The role of paraoxonase in cancer

The paraoxonase (PON) gene family includes three proteins, PON1, PON2 and PON3. PON1 and PON3 are both associated with high-density lipoprotein (HDL) particles and exert anti-oxidant and anti-inflammatory properties. PON2 and PON3 are intracellular enzymes which modulate mitochondrial superoxide anion production and endoplasmic reticulum (ER) stress-induced apoptosis. The pleiotropic roles exerted by PONs have been mainly investigated in cardiovascular and neurodegenerative diseases. In recent years, overexpression of PON2 and PON3 has been observed in cancer cells and it has been proposed that both enzymes could be involved in tumor survival and stress resistance. Moreover, a lower activity of serum PON1 has been reported in cancer patients. This review summarizes literature data on the role of PONs in human cancers and their potential role as a target for antitumor drugs.

Paraoxonase-1 (PON1) induces metastatic potential and apoptosis escape via its antioxidative function in lung cancer cells

Paraoxonase-1 (PON1) gene polymorphisms have been closely associated with the development of advanced cancers while PON1 secretion to the serum is linked with inhibition of oxidized high-density lipoprotein by its antioxidative function. Our group previously demonstrated that post-translational modification of serum PON1 in form of fucosylated PON1 is a potential biomarker of small cell lung cancer. Here, we interrogated the role of PON1 in the pathobiology of lung cancer (LC) by addressing cell-autonomous mechanisms using gain-of-function and loss-of-function approaches and protein expression profiling of tissue samples in our clinical biobank. PON1 expression in LC patient tissues varied between overexpression in squamous cell carcinoma and minimal loss in adenocarcinoma sub-types. Simultaneous overexpression of PON1 both at the gene and protein stability levels induced pro-oncogenic characteristics in LC cells and xenografts. PON1 overexpression supported metastatic progression of LC by decreasing G1/S ratio and LC cell senescence involving p21Waf1/Cip1. PON1 suppressed drug- and ligand-induced cell death and protected LC cells from genotoxic damages with maintained ATP levels, requiring p53-directed signals. PON1 promoted ROS deregulation protecting the mitochondria from dysregulation. PON1 knockdown resulted in the blockage of its antioxidant function in LC cells through Akt signaling with reduced invasive signature as a consequence of scant expression. Targeted glycolysis stimulated PON1 antioxidant activity regulating phosphorylation of AMPK-α. The functional data imply that exploitation of the antioxidative function of PON1 is consequential in driving LC pathogenesis at the cell-autonomous mechanistic level with consequences on tumor growth.

Downregulation of paraoxonase 3 contributes to aggressive human hepatocellular carcinoma progression and associates with poor prognosis

Paraoxonase (PON) enzymes possess antioxidant properties and protect against cardiovascular diseases. As a member of PON family, PON3 is primarily synthesized in the liver and poorly investigated. This study aimed to examine the expression of PON3 in human hepatocellular carcinoma (HCC) and investigate the clinical significance and biological function of PON3 in HCC patients. We first analyzed PON3 expression in 50 paired HCC samples (HCC tissues vs matched para-cancerous tissues) and 160 clinical HCC specimens by using immunohistochemistry (IHC). Our results showed that the expression of PON3 was downregulated in HCC and significantly associated with tumor-node-metastasis (TNM) stage, tumor size, and tumor number. Kaplan-Meier survival and Cox regression analyses showed that PON3 was an independent prognostic factor for overall survival (OS) and time to recurrence (TTR). Finally, we aimed to reveal the biological function of PON3 in HCC growth and metastasis, and our results showed that overexpression of PON3 potently inhibited growth and metastasis of HCC. Collectively, our study demonstrated that PON3 exhibited tumor-suppressive effects toward HCC and it might serve as a novel prognostic marker in HCC.

Paraoxsonase2 (PON2) and oxidative stress involvement in pomegranate juice protection against cigarette smoke-induced macrophage cholesterol accumulation

Exposure to cigarette smoke (CS) promotes various stages of atherosclerosis development. Macrophages are the predominant cells in early atherogenesis, and the polyphenolic-rich pomegranate juice (PJ) is known for its protective role against macrophage atherogenicity. The aim of the current study was to examine the atherogenic effects of CS on macrophages, and to evaluate the protective effects of PJ against CS-induced macrophage atherogenicity. Murine J774A.1 macrophages were treated with CS-exposed medium in the absence or presence of PJ. Parameters of lipid peroxidation in CS-exposed medium were measured by the lipid peroxides and thiobarbituric acid reactive substances (TBARS) assays. Atherogenicity of macrophages incubated with increasing concentrations of CS-exposed medium was assessed by cytotoxicity, oxidative stress determined by generation of reactive oxygen species (ROS) using DCFH-DA, activity of the cellular anti-oxidant paraoxonase2 (PON2), macrophage accumulation of cholesterol and triglycerides, as well as through high density lipoprotein (HDL)-mediated cholesterol efflux from the cells. CS exposure resulted in significant and dose-dependent increases in lipid peroxides and TBARS medium levels (up to 3 and 8-fold, respectively). Incubation of macrophages with CS-exposed medium resulted in dose-dependent increases in macrophage damage/injury (up to 6-fold), intracellular ROS levels (up to 31%), PON2 activity (up to 2-fold), and macrophage cholesterol content (up to 24%). The latter might be explained by reduced HDL-mediated cholesterol efflux from CS-exposed macrophages (by 21%). PJ protected macrophages from CS-induced increases in intracellular ROS levels and cholesterol accumulation, as well as the attenuated efflux of cholesterol. These data indicate that CS stimulates macrophage oxidation and activates PON2 as a possible compensatory response to the oxidative burden. CS impairs HDL-mediated cholesterol efflux from macrophages leading to cellular accumulation of cholesterol. The atherogenic and oxidative effects of CS are attenuated by PJ, a polyphenolic-rich anti-oxidant.

Genetic epidemiology of coronary artery disease: an Asian Indian perspective

Coronary artery disease (CAD) has emerged as a major cause of morbidity and mortality worldwide. Recent findings on the role of genetic factors in the aetiopathology of CAD have implicated novel genes and variants in addition to those involved in lipid and lipoprotein metabolism. However, our present knowledge is limited due to lack of clarity on their exact identity and the quantum of impact on disease susceptibility, and incident risk. It is a matter of great interest to understand the role of genetic factors in ethnic populations that have a strong underlying predisposition to CAD such as the South Asian populations, particularly among Asian Indians living in India and abroad. Although, a number of isolated studies do implicate certain gene polymorphisms towards enhanced disease susceptibility, the available data remains scanty and inconclusive as they have not been validated in large, prospective cohorts. The present review aims to consolidate the available literature on the genetics of CAD in Asian Indians and seeks to provide insights on the concerns that need to be addressed in future studies to generate information having clinical value.

Immunohistochemical analysis of paraoxonases and chemokines in arteries of patients with peripheral artery disease

Oxidative damage to lipids and lipoproteins is implicated in the development of atherosclerotic vascular diseases, including peripheral artery disease (PAD). The paraoxonases (PON) are a group of antioxidant enzymes, termed PON1, PON2, and PON3 that protect lipoproteins and cells from peroxidation and, as such, may be involved in protection against the atherosclerosis process. PON1 inhibits the production of chemokine (C–C motif) ligand 2 (CCL2) in endothelial cells incubated with oxidized lipoproteins. PON1 and CCL2 are ubiquitously distributed in tissues, and this suggests a joint localization and combined systemic effect. The aim of the present study has been to analyze the quantitative immunohistochemical localization of PON1, PON3, CCL2 and CCL2 receptors in a series of patients with severe PAD. Portions of femoral and/or popliteal arteries from 66 patients with PAD were obtained during surgical procedures for infra-inguinal limb revascularization. We used eight normal arteries from donors as controls. PON1 and PON3, CCL2 and the chemokine-binding protein 2, and Duffy antigen/chemokine receptor, were increased in PAD patients. There were no significant changes in C–C chemokine receptor type 2. Our findings suggest that paraoxonases and chemokines play an important role in the development and progression of atherosclerosis in peripheral artery disease.

Human paraoxonase-1 (PON1): Gene structure and expression, promiscuous activities and multiple physiological roles

Human PON1 is a HDL-associated lipolactonase capable of preventing LDL and cell membrane oxidation and is therefore considered to be atheroprotective. PON1 contributes to the antioxidative function of HDL and reductions in HDL-PON1 activity, prevalent in a wide variety of diseases with an inflammatory component, are believed to lead to dysfunctional HDL which can promote inflammation and atherosclerosis. However, PON1 is multifunctional and may contribute to other HDL functions such as in innate immunity, preventing infection by quorum sensing gram negative bacteria by destroying acyl lactone mediators of quorum sensing, and putative new roles in cancer development and the promotion of healthy ageing. In this review we explore the physiological roles of PON1 in disease development, as well as PON1 gene and protein structure, promiscuous activities and the roles of SNPs and ethnicity in determining PON1 activity.

Negative association between paraoxonase 2, anthropometric markers and metabolic syndrome

Background Metabolic syndrome (MS) has a great impact on cardiovascular mortality and morbidity. Our aim was to investigate the association of MS with some oxidant and antioxidant markers, including pro-and antioxidant status of peripheral blood mononuclear cells (PBMC) in newly diagnosed type 2 diabetic mellitus patients (ND-T2D). Methods 219 ND-T2D and 88 healthy subjects were divided in two groups according to the absence or presence of MS. Anthropometric measurements, routine blood tests, total oxidant status (TOS), total antioxidant status (TAS) and ELISA measurements were included. The PBMC capacity to release free radicals and to neutralize them was also determined by measuring the respiratory burst (RB) together with the lactonase activity of the intracellular antioxidant enzyme paraoxonase 2 (PON2). Results Comparing ND-T2D MS+ with those MS- the RB of the PBMC was significantly higher (p<0.05) while lactonase PON2 enzymatic activity was decreased (p < 0.001). A negative correlation of RB was found with TAS (r = -0.416, p < 0.05). PON2 was also negatively correlated with glycaemia (r = -0.275, p < 0.001), HbA1c (r = -0.308, p < 0.001), weight (r = -0.183; p < 0.05), waist circumference (r = -0.353, p < 0.001) and body mass index (r = -0.290, p < 0.001). Conclusion PON2 lactonase activity is negatively associated with anthropometric markers in ND-T2D with MS.

Association between paraoxonases gene expression and oxidative stress in hepatotoxicity induced by CCl4

Objectives. The purpose of the study is to evaluate the hepatoprotective effect of rutin in carbon tetrachloride- (CCl₄-) induced liver injuries in rat model. Methods. Forty male Wistar albino rats were divided into four groups. Group I was the control group and received dimethyl sulphoxide (DMSO) and olive oil. Group II received rutin. Groups III was treated with CCl₄. Group IV was administered rutin after 48 h of CCl₄ treatment. Liver enzymes level, lipid profile, lipid peroxidation, and hydrogen peroxide were measured. The genes expression levels were monitored by real time RT-PCR and western blot techniques. Results. CCl₄ group showed significant increase in alanine aminotransferase (ALT), aspartate aminotransferase (AST), thiobarbituric acid reactive substances (TBAR), hydrogen peroxide (H₂O₂), and lipid profile and a significant decrease in glutathione peroxidase (GPx), glutathione S transferase (GST), catalase (CAT), paraoxonase-1 (PON-1), paraoxonase-3 (PON-3), peroxisome proliferator activated receptor delta (PPAR-δ), and ATP-binding cassette transporter 1 (ABAC1) genes expression levels. Interestingly, rutin supplementation completely reversed the biochemical and gene expression levels induced by CCl₄ to control values. Conclusion. CCl₄ administration causes aberration of genes expression levels in oxidative stress pathway resulting in DNA damage and hepatotoxicity. Rutin causes hepatoprotective effect through enhancing the antioxidant genes.

Inflammation, infection, cancer and all that…the role of paraoxonases

The paraoxonase (PON) gene family consists of three members, PON1, PON2 and PON3. All PON proteins possess antioxidant properties and lipo-lactonase activities, and are implicated in the pathogenesis of several inflammatory diseases including atherosclerosis, Alzheimer's, Parkinson's, diabetes and cancer. Despite the role of PON proteins in critical cellular functions and associated pathologies, the physiological substrates and molecular mechanisms by which PON proteins function as anti-inflammatory proteins remain largely unknown. PON1 is found exclusively extracellular and associated solely with high-density lipoprotein (HDL) particles in the circulation, and, in part, confers the anti-oxidant and anti-inflammatory properties associated with HDL. Recent studies demonstrated that the intracellular PON proteins; PON2 and PON3 (i) are associated with mitochondria and mitochondria-associated membranes, (ii) modulate mitochondria-dependent superoxide production, and (iii) prevent apoptosis. Overexpression of PON2 and PON3 genes protected (i) mitochondria from antimycin or oligomycin mediated mitochondrial dysfunction and (ii) ER stress and ER stress mediated mitochondrial dysfunction. These studies illustrate that the anti-inflammatory effects of PON2 and PON3 may, in part, be mediated by their role in mitochondrial and associated organelle function. Since oxidative stress as a result of mitochondrial dysfunction is implicated in the development of inflammatory diseases including atherosclerosis and cancer, these recent studies on PON2 and PON3 proteins may provide a mechanism for the scores of epidemiological studies that show a link between PON genes and numerous inflammatory diseases. Understanding such mechanisms will provide novel routes of intervention in the treatment of diseases associated with pro-inflammatory oxidative stress.

Role of PON2 in innate immune response in an acute infection model

N-(3-oxododecanoyl)-l-homoserine lactone (3OC(12)-HSL) is a quorum-sensing molecule produced by gram-negative microbial pathogens such as Pseudomonas aeruginosa (PAO1). 3OC(12)-HSL is involved in the regulation of bacterial virulence factors and also alters the function of the host immune cells. Others and we have previously shown that paraoxonase 2 (PON2), a member of the paraoxonase gene family expressed in immune cells, hydrolyzes 3OC(12)-HSL. In this study, we examined i) whether macrophage PON2 participates in 3OC(12)-HSL hydrolysis, ii) the effect of PON2 deficiency in acute PAO1 infection in mice and iii) the effect of 3OC(12)-HSL on PON2 deficient (PON2-def) macrophages. When compared to wild type macrophages, both intact cells and membrane-enriched protein lysates obtained from PON2-def macrophages show a marked impairment in their ability to hydrolyze 3OC(12)-HSL. PON2 expression (message and protein) is not altered in response to 3OC(12)-HSL in macrophages. 3OC(12)-HSL treated PON2-def macrophages showed i) an increase in ER stress and oxidative stress, ii) defective phosphatidylinositol 3-kinase (PI3 kinase)/AKT activation, and iii) reduced phagocytosis function. Moreover, the nitration to phosphorylation ratio of Tyr458 in p85 protein, the regulatory subunit of PI3-kinase that has been correlated with the phagocytosis function of macrophages, was increased in PON2-def macrophages. Antioxidant treatment reversed the effects of PON2 deficiency in macrophage phagocytosis function. Furthermore, following administration of 1.6 × 10(7) CFU of PAO1, bacterial clearance was significantly reduced in the lungs (5.7 fold), liver (2.5 fold), and spleen (14.8 fold) of PON2-def mice when compared to wild type mice. Our results suggest that PON2 plays an important role in innate immune defense against PAO1 infection.

Renal dopamine receptors, oxidative stress, and hypertension

Dopamine, which is synthesized in the kidney, independent of renal nerves, plays an important role in the regulation of fluid and electrolyte balance and systemic blood pressure. Lack of any of the five dopamine receptor subtypes (D1R, D2R, D3R, D4R, and D5R) results in hypertension. D1R, D2R, and D5R have been reported to be important in the maintenance of a normal redox balance. In the kidney, the antioxidant effects of these receptors are caused by direct and indirect inhibition of pro-oxidant enzymes, specifically, nicotinamide adenine dinucleotide phosphate, reduced form (NADPH) oxidase, and stimulation of anti-oxidant enzymes, which can also indirectly inhibit NADPH oxidase activity. Thus, stimulation of the D2R increases the expression of endogenous anti-oxidants, such as Parkinson protein 7 (PARK7 or DJ-1), paraoxonase 2 (PON2), and heme oxygenase 2 (HO-2), all of which can inhibit NADPH oxidase activity. The D5R decreases NADPH oxidase activity, via the inhibition of phospholipase D2, and increases the expression of HO-1, another antioxidant. D1R inhibits NADPH oxidase activity via protein kinase A and protein kinase C cross-talk. In this review, we provide an overview of the protective roles of a specific dopamine receptor subtype on renal oxidative stress, the different mechanisms involved in this effect, and the role of oxidative stress and impairment of dopamine receptor function in the hypertension that arises from the genetic ablation of a specific dopamine receptor gene in mice.

Paraoxonase-1 (PON1) promoter region polymorphisms, serum PON1 status and coronary heart disease

INTRODUCTION

Serum paraoxonase-1 (PON1) retards the oxidation of low-density lipoprotein and cell membranes and is atheroprotective. Polymorphisms in the promoter region of the PON1 gene have been shown to affect serum PON1 levels and have been related to the presence of coronary heart disease (CHD) in some studies. However, contradictory results have been reported with regard to promoter region polymorphisms and CHD presence; therefore we have re-examined the effects of the C-108T and G-909C promoter polymorphisms on PON1 levels and the presence of CHD in a large case-control study.

MATERIAL AND METHODS

Paraoxonase-1 activity, concentration and the C-108T and G-909C polymorphisms were measured in 417 people with CHD and 282 healthy controls, in a case control study.

RESULTS

Paraoxonase-1 activity and concentration were significantly lower in the CHD population compared to controls regardless of their C-108T and G-909C genotype (p < 0.001). Paraoxonase-1 activity was significantly different in the C-108T genotypes in both the control and CHD groups in the order TT < TC < CC (p < 0.01). Paraoxonase-1 concentration was significantly different in the CHD group only in the G-909C genotype in the order GG > GC > CC (p < 0.01). Haplotype analysis revealed no consistent patterns of PON1 activity in the CHD population; however, in the controls PON1 activity differed between haplotypes GGCC > GGTC > GGTT (p < 0.05) and GCCC > GCTC > GCTT (p < 0.02). Neither promoter polymorphism was associated with CHD presence.

CONCLUSIONS

Paraoxonase-1 status was significantly lower in people with CHD and was affected by the promoter region polymorphisms.

In comparison with palm oil, dietary nut supplementation delays the progression of atherosclerotic lesions in female apoE-deficient mice

Epidemiological studies have demonstrated the benefits of nut consumption on cardiovascular risk factors and CHD, attributed to their fatty acid profile, rich in unsaturated fatty acids, and also to other nutrients. The effect of nuts on atherosclerotic lesions was studied in female and male apoE-knockout mice fed a diet supplemented with 3 % (w/w) mixed nuts (mix: almonds, hazelnuts and walnuts in a proportion of 0.25:0·25:0.50, respectively), and compared with mice receiving an isoenergetic diet of similar fat content provided as palm oil. After 12 weeks, plasma lipid parameters and aortic lesions were measured. Males receiving nuts had lower plasma cholesterol than the palm oil group, and both sex groups had lower plasma non-HDL-cholesterol and lower content of reactive oxygen species in LDL than mice receiving the palm oil diet, the latter decrease being more pronounced in females than in males. Females consuming the nut diet showed a smaller aortic lesion area than those consuming palm oil, whereas no differences were observed in males. In females, hepatic paraoxonase 2 (Pon2) mRNA increased, and no change was observed in prenylcysteine oxidase 1 (Pcyox1) expression after the consumption of the nut-containing diet. In addition, aortic atherosclerotic lesions correlated directly with total plasma cholesterol and inversely with hepatic Pon2 expression. The results suggest that the beneficial effect of nut intake in female apoE-deficient mice may be attributed to reduced non-HDL-cholesterol levels and enhanced PON2 antioxidant activity.

Macrophage paraoxonase 2 regulates calcium homeostasis and cell survival under endoplasmic reticulum stress conditions and is sufficient to prevent the development of aggravated atherosclerosis in paraoxonase 2 deficiency/apoE-/- mice on a Western diet

Paraoxonase 2 deficiency (PON2-def) alters mitochondrial function and exacerbates the development of atherosclerosis in mice. PON2 overexpression protects against ER stress in cell culture. In this paper, we examined the role of PON2 in the unexplored link between ER stress and mitochondrial dysfunction and tested whether restoration of PON2 in macrophages is sufficient to reduce aggravated atherosclerosis in PON2-def/apoE(-/-) mice on a Western diet. ER stress response genes, intracellular calcium levels, and apoptotic nuclei were significantly elevated in PON2-def/apoE(-/-) macrophages compared to apoE(-/-) macrophages in response to ER stressors, but not at the basal level. In contrast, PON2-def/apoE(-/-) macrophages exhibited greater mitochondrial stress at the basal level, which was further worsened in response to ER stressors. There was no difference in ER stress response genes and apoptotic nuclei between apoE(-/-) and PON2-def/apoE(-/-) macrophages when pretreated with xestospongin (which blocks the release of calcium from ER) suggesting that PON2 modulates cell survival and ER stress by maintaining calcium homeostasis. Treatment with a mitochondrial calcium uptake inhibitor, RU360, attenuated ER stressor mediated mitochondrial dysfunction in PON2-def/apoE(-/-) macrophages. CHOP expression (ER stress marker) and apoptotic nuclei were significantly higher in aortic lesions of PON2-def/apoE(-/-) mice compared to apoE(-/-) mice fed a Western diet. Restoration of PON2 in macrophages reduced ER stress, mitochondrial dysfunction and apoptosis in response to ER stressors. Furthermore, restoration of PON2 in macrophages reduced lesional apoptosis and atherosclerosis in PON2-def/apoE(-/-) mice on a Western diet. Our data suggest that macrophage PON2 modulates mechanisms that link ER stress, mitochondrial dysfunction and the development of atherosclerosis.

Modulation of paraoxonases during infectious diseases and its potential impact on atherosclerosis

The paraoxonase (PON) gene family includes three members, PON1, PON2 and PON3, aligned in tandem on chromosome 7 in humans and on chromosome 6 in mice. All PON proteins share considerable structural homology and have the capacity to protect cells from oxidative stress; therefore, they have been implicated in the pathogenesis of several inflammatory diseases, particularly atherosclerosis. The major goal of this review is to highlight the modulation of each of the PONs by infective (bacterial, viral and parasitic) agents, which may shed a light on the interaction between infectious diseases and PONs activities in order to effectively reduce the risk of developing atherosclerosis.

Protectors or Traitors: The Roles of PON2 and PON3 in Atherosclerosis and Cancer

Cancer and atherosclerosis are major causes of death in western societies. Deregulated cell death is common to both diseases, with significant contribution of inflammatory processes and oxidative stress. These two form a vicious cycle and regulate cell death pathways in either direction. This raises interest in antioxidative systems. The human enzymes paraoxonase-2 (PON2) and PON3 are intracellular enzymes with established antioxidative effects and protective functions against atherosclerosis. Underlying molecular mechanisms, however, remained elusive until recently. Novel findings revealed that both enzymes locate to mitochondrial membranes where they interact with coenzyme Q10 and diminish oxidative stress. As a result, ROS-triggered mitochondrial apoptosis and cell death are reduced. From a cardiovascular standpoint, this is beneficial given that enhanced loss of vascular cells and macrophage death forms the basis for atherosclerotic plaque development. However, the same function has now been shown to raise chemotherapeutic resistance in several cancer cells. Intriguingly, PON2 as well as PON3 are frequently found upregulated in tumor samples. Here we review studies reporting PON2/PON3 deregulations in cancer, summarize most recent findings on their anti-oxidative and antiapoptotic mechanisms, and discuss how this could be used in putative future therapies to target atherosclerosis and cancer.

Novel associations of nonstructural Loci with paraoxonase activity

The high-density-lipoprotein-(HDL-) associated esterase paraoxonase 1 (PON1) is a likely contributor to the antioxidant and antiatherosclerotic capabilities of HDL. Two nonsynonymous mutations in the structural gene, PON1, have been associated with variation in activity levels, but substantial interindividual differences remain unexplained and are greatest for substrates other than the eponymous paraoxon. PON1 activity levels were measured for three substrates-organophosphate paraoxon, arylester phenyl acetate, and lactone dihydrocoumarin-in 767 Mexican American individuals from San Antonio, Texas. Genetic influences on activity levels for each substrate were evaluated by association with approximately one million single nucleotide polymorphism (SNPs) while conditioning on PON1 genotypes. Significant associations were detected at five loci including regions on chromosomes 4 and 17 known to be associated with atherosclerosis and lipoprotein regulation and loci on chromosome 3 that regulate ubiquitous transcription factors. These loci explain 7.8% of variation in PON1 activity with lactone as a substrate, 5.6% with the arylester, and 3.0% with paraoxon. In light of the potential importance of PON1 in preventing cardiovascular disease/events, these novel loci merit further investigation.

PON3 is upregulated in cancer tissues and protects against mitochondrial superoxide-mediated cell death

To achieve malignancy, cancer cells convert numerous signaling pathways, with evasion from cell death being a characteristic hallmark. The cell death machinery represents an anti-cancer target demanding constant identification of tumor-specific signaling molecules. Control of mitochondrial radical formation, particularly superoxide interconnects cell death signals with appropriate mechanistic execution. Superoxide is potentially damaging, but also triggers mitochondrial cytochrome c release. While paraoxonase (PON) enzymes are known to protect against cardiovascular diseases, recent data revealed that PON2 attenuated mitochondrial radical formation and execution of cell death. Another family member, PON3, is poorly investigated. Using various cell culture systems and knockout mice, here we addressed its potential role in cancer. PON3 is found overexpressed in various human tumors and diminishes mitochondrial superoxide formation. It directly interacts with coenzyme Q10 and presumably acts by sequestering ubisemiquinone, leading to enhanced cell death resistance. Localized to the endoplasmic reticulum (ER) and mitochondria, PON3 abrogates apoptosis in response to DNA damage or intrinsic but not extrinsic stimulation. Moreover, PON3 impaired ER stress-induced apoptotic MAPK signaling and CHOP induction. Therefore, our study reveals the mechanism underlying PON3's anti-oxidative effect and demonstrates a previously unanticipated function in tumor cell development. We suggest PONs represent a novel class of enzymes crucially controlling mitochondrial radical generation and cell death.

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.

Immunohistochemical analysis of paraoxonases-1 and 3 in human atheromatous plaques

BACKGROUND

The paraoxonase (PON) enzyme family comprising PON1, PON2 and PON3 are antioxidant enzymes that degrade bioactive oxidised lipids and are thus antiatherogenic.

MATERIALS AND METHODS

We investigated the localisation of the PON proteins during the development of atherosclerosis by immunohistochemical analysis.

RESULTS

In normal aortas, PON1 and PON3 were localised to smooth muscle cells (SMC) and endothelial cells. PON3 staining was stronger than that of PON1. During atherosclerosis development, SMC staining for PON1 and PON3 was greatly reduced, while macrophage staining for both proteins increased with PON1 predominating. Macrophage staining for PON1 and PON3 was significantly and positively related to the amount of aortic inflammation (both P<0·001).

CONCLUSIONS

Our data add support to the growing body of evidence for a cellular protective effect of PON1 and PON3 against the proinflammatory/proatherosclerotic effects of lipid peroxidation.

Paraoxonase 2 deficiency alters mitochondrial function and exacerbates the development of atherosclerosis

Increased production of reactive oxygen species (ROS) as a result of decreased activities of mitochondrial electron transport chain (ETC) complexes plays a role in the development of many inflammatory diseases, including atherosclerosis. Our previous studies established that paraoxonase 2 (PON2) possesses antiatherogenic properties and is associated with lower ROS levels. The aim of the present study was to determine the mechanism by which PON2 modulates ROS production. In this report, we demonstrate that PON2-def mice on the hyperlipidemic apolipoprotein E(-/-) background (PON2-def/apolipoprotein E(-/-)) develop exacerbated atherosclerotic lesions with enhanced mitochondrial oxidative stress. We show that PON2 protein is localized to the inner mitochondrial membrane, where it is found associated with respiratory complex III. Employing surface-plasmon-resonance, we demonstrate that PON2 binds with high affinity to coenzyme Q(10), an important component of the ETC. Enhanced mitochondrial oxidative stress in PON2-def mice was accompanied by significantly reduced ETC complex I + III activities, oxygen consumption, and adenosine triphosphate levels in PON2-def mice. In contrast, overexpression of PON2 effectively protected mitochondria from antimycin- or oligomycin-mediated mitochondrial dysfunction. Our results illustrate that the antiatherogenic effects of PON2 are, in part, mediated by the role of PON2 in mitochondrial function.

Tissue distribution and expression of paraoxonases and chemokines in mouse: the ubiquitous and joint localisation suggest a systemic and coordinated role

A vicious cycle between oxidation and inflammation leads to complications in a growing number of disease states. Knowledge on tissue distribution of chemokines, mediators of inflammatory response, and paraoxonases, with antioxidant and anti-inflammatory actions, may be relevant. Using immunohistochemistry and quantitative real-time PCR we have investigated the distribution of PON1, 2 and 3, CCL2, 7, 8 and 12 and the chemokine receptor CCR2 protein and mRNA in 23 tissues from C57BL/6J mice. As expected, PON1, 2 and 3, CCL2, 7, 8 and 12 and CCR2 proteins were present in the vast majority of tissues investigated. Surprisingly, mRNA for these proteins was also expressed in most of these tissues suggesting local production and the ability to respond in situ to inflammatory stimuli. The wide distribution and expression of mRNA for paraoxonases and CC-chemokines suggest a systemic, probably coordinated, role in the overall inflammatory response.

Cardiovascular disease complications in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a highly variable autoimmune disease characterized by aberrant host-immune responses and chronic inflammation. Recently, a strong association between cardiovascular (CV) disease and SLE has emerged. Thus, low serum, high-density lipoprotein strongly correlated with elevated erythrocyte sedimentation rate, IL-6, TNF-alpha and the SLE disease activity index after adjusting for age, gender, race, BMI, insulin sensitivity and any concurrent drug use. In SLE, CV disease is characterized by increased VEGF, which may alter vascular hemostasis and promote neoangiogenesis. Increased low-density lipoprotein-cholesterol and proinflammatory high-density lipoprotein-cholesterol uptake by monocytes together with enhanced low-density lipoprotein-cholesterol oxidation results in the deposition of altered cholesterol forms into the vascular wall. This contributes to precocious and accelerated development of coronary artery plaques. Cholesterol-reducing drugs should be considered in the standard of care of SLE patients, especially in those with an unfavorable CV disease risk profile, which could reduce the probability of atherosclerosis progressing to CV disease or stroke in these patients.

Independent predictive roles of eotaxin Ala23Thr, paraoxonase 2 Ser311Cys and beta-adrenergic receptor Trp64Arg polymorphisms on cardiac disease in Type 2 Diabetes--an 8-year prospective cohort analysis of 1297 patients

AIMS

To examine the independent and joint effects of multiple genetic variants on a cardiac end-point in an 8-year prospective study of a Chinese diabetic cohort.

METHODS

Seventy-seven single nucleotide polymorphisms (SNPs) of 53 candidate genes for inflammation, thrombosis, vascular tone regulation and lipid metabolism were genotyped in 1297 Chinese patients with no prior history of coronary heart disease (CHD) or heart failure at baseline. Cardiac end-point was defined by the occurrence of CHD and/or heart failure.

RESULTS

In Cox regression model, after adjustment for baseline confounding variables including age, sex, smoking status, duration of diabetes, glycaemic control, lipid levels, waist circumference, blood pressure, albuminuria and estimated glomerular filtration rate, genetic variants, including Ala/Ala of SCYA11 (eotaxin) Ala23Thr, Cys/Cys or Cys/Ser of PON2 (paraoxonase 2) Ser311Cys and Arg/Arg of ADRB3 (beta3-adrenergic receptor) Trp64Arg, were independently associated with incident cardiac end-point, with respective hazard ratios (95% confidence interval) of 1.70 (1.10-2.61, P=0.037), 1.42 (1.08-1.88, P=0.013) and 3.84 (1.18-12.50, P=0.025). Analysis of the joint effect of the risk alleles showed significant increased risk of the cardiac end-point with increasing number of risk alleles (P<0.001). The adjusted risk for the cardiac end-point was 4.11 (P=0.002) for patients carrying four risk alleles compared with those carrying one or no risk allele.

CONCLUSIONS

The independent risk conferred by genetic variants encoding pathways such as inflammation and lipid metabolism, not adequately reflected by conventional biomarkers, may identify high-risk individuals for intensified control of modifiable risk factors.

HDL lipids and insulin resistance

There is renewed interest in high-density lipoproteins (HDLs) due to recent findings linking atherosclerosis to the formation of dysfunctional HDL. This article focuses on the universe of HDL lipids and their potential protective or proinflammatory roles in vascular disease and insulin resistance. HDL carries a wide array of lipids including sterols, triglycerides, fat-soluble vitamins, and a large number of phospholipids, including phosphatidylcholine, sphingomyelin, and ceramide with many biological functions. Ceramide has been implicated in the pathogenesis of insulin resistance and has many proinflammatory properties. In contrast, sphingosine-1-phosphate, which is transported mainly in HDL, has anti-inflammatory properties that may be atheroprotective and may account for some of the beneficial effects of HDL. However, the complexity of the HDL lipidome is only beginning to reveal itself. The emergence of new analytical technologies should rapidly increase our understanding of the function of HDL lipids and their role in disease states.

Directed evolution of serum paraoxonase PON3 by family shuffling and ancestor/consensus mutagenesis, and its biochemical characterization

Serum paraoxonases (PONs) are calcium-dependent lactonases with anti-atherogenic and detoxification functions. Here we describe the directed evolution and characterization of recombinant variants of serum paraoxonase PON3 that express in an active and soluble manner in Escherichia coli. These variants were obtained by combining family shuffling and phylogeny-based mutagenesis: the limited diversity of accessible, cloned PON3 genes was complemented by spiking the shuffling reaction with ancestor/consensus mutations, mutations to residues that comprise the consensus or appear in the predicted ancestors of the PON family. We screened the resulting libraries for PON3's lactonase activity while ensuring that the selected variants retained the substrate specificity of wild-type mammalian PON3s. The availability of highly stable, recombinant PON3 that is free of all other serum components enabled us to explore unknown biochemical features of PON3, including its binding to HDL particles, the effect of HDL on PON3's stability and enzymatic activity, and ex vivo tests of its anti-atherogenic properties. Overall, it appears that PON3 possesses properties very similar to those of PON1: the enzyme's lactonase activity is selectively stimulated by binding to apoAI-HDL, with a concomitant increase in its stability. PON3 also exhibits potentially anti-atherogenic functions, although at levels lower than those of PON1.

Human paraoxonase gene cluster transgenic overexpression represses atherogenesis and promotes atherosclerotic plaque stability in ApoE-null mice

The paraoxonase (PON) gene cluster consists of the PON1, PON2, and PON3 genes, each of which can individually inhibit atherogenesis. To analyze the functions of the PON gene cluster (PC) in atherogenesis and plaque stability, human PC transgenic (Tg) mice were generated using bacterial artificial chromosome. The high-density lipoprotein from Tg mice exhibited increased paraoxonase activity. When crossed to the ApoE-null background and challenged by high-fat diet, PC Tg/ApoE-null mice formed significantly fewer atherosclerotic lesions. However overexpression of the PC transgene had no additive effect on atherosclerosis compared to the overexpression of the single PON1 or PON3 transgene. Plaques from PC Tg/ApoE-null mice exhibited increased levels of collagen and smooth muscle cells, and reduced levels of macrophages and lipid, compared with those from ApoE-null mice, indicating lesions of PC Tg/ApoE-null mice had characteristics of more stable plaques than those of ApoE-null mice. PC transgene enhanced high-density lipoprotein ability to protect low-density lipoprotein against oxidation in vitro. Serum intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 were also repressed by PC transgene. Proatherogenic reactions of Tg mouse peritoneal macrophages induced by oxidized low-density lipoprotein were inhibited by PC transgene, as indicated by reduced reactive oxygen species generation, inflammation, matrix metalloproteinase-9 expression, and foam cell formation. Our results demonstrate that the PC transgene not only represses atherogenesis but also promotes atherosclerotic plaque stability in vivo. PC may therefore be a useful target for atherosclerosis treatment.

Paraoxonases role in the prevention of cardiovascular diseases

Increased oxidative stress is a characteristic of patients with high risk for atherosclerosis development (hypercholesterolemic, hypertensive, diabetic), and the above phenomenon was shown to be associated with attenuated antioxidative status. The increased oxidative stress in atherosclerotic patients is present in their blood, as well as in their arterial wall cells, including macrophages, the hallmark of foam cells formation during early atherogenesis. Serum high density lipoprotein (HDL)-associated paraoxonase 1 (PON1) reduces oxidative stress in lipoproteins, in macrophages, and in the atherosclerotic lesion, whereas paraoxonase 2 (PON2, which is present in tissues, but not in serum) acts as an antioxidant at the cellular and not humoral level. Both PON1 and PON2 protect against atherosclerosis development, and this phenomenon could be related to their antioxidative properties. The use of nutritional antioxidants such as vitamin E, carotenoids (lycopene and beta-carotene), and mainly polyphenols (such as those present in red wine, licorice root ethanolic extract, or in pomegranate) by atherosclerotic animals and also by cardiovascular patients, leads to a reduction in oxidative stress and to the attenuation of atherosclerosis development. These latter phenomena could be related to the nutritional antioxidants-induced increase in HDL PON1 activity (effects on gene expression, on preventing enzyme inactivation, and on increasing PON1 stability through its binding to HDL), as well as an increase in macrophage PON2 activation (at the gene expression level).