Association of PON1 gene polymorphisms and enzymatic activity with risk of coronary artery disease

CDKN2B-AS (rs2891168), SOD2 (rs4880), and PON1 (rs662) polymorphisms and susceptibility to coronary artery disease and type 2 diabetes mellitus in Iranian patients: A case-control study

Background and Aims

Coronary artery disease (CAD) is a devastating illness and primary cause of death worldwide that arises from a combination of genetic and environmental factors. Several large-scale studies found that 9p21.3, superoxide dismutase 2 (SOD2), and paraoxonase 1 (PON1) polymorphisms increase type 2 diabetes mellitus (T2DM) and/or coronary artery disease (CAD) risk. Our research aimed to investigate whether the SNPs of the 9p21.3 locus (rs28911698), SOD2 (rs4880), and PON1 (rs662) genes were associated with the risk of T2DM and/or CAD in the Iranian population.

Methods

In this case-control study four group subjects including patients with CAD non-T2DM, with CAD and T2DM, non-CAD with T2DM, and non-CAD non-T2DM were recruited to the study from 2019 to 2020. Molecular analysis was carried out by allele specific-polymerase chain reaction (AS-PCR) technique for rs4880, Taqman genotyping assay for rs2891168, and PCR followed by restriction fragment length polymorphism (PCR-RFLP) technique for rs662.

Results

The rs2891168 polymorphism presented an elevated risk of CAD in non-T2DM with CAD and with T2DM CAD groups compared to the non-T2DM non-CAD group with GG genotype and dominant model after adjustment (p < 0.05). G-allele in PON1 rs662 polymorphism associated with increased risk of T2DM in T2DM non-CAD, and T2DM CAD groups compared to non-T2DM non-CAD group with dominant model, GG and AG genotypes (p < 0.05). However, SOD2 rs4880 polymorphism presented no significant association with the development of diabetes or CAD.

Conclusion

These results provide a prime witness that rs2891168 and rs662 gene variants might have a possible increased risk of CAD and T2DM occurrence, respectively. To obtain more definitive and accurate results in this area, further research is required.

HDL Function and Atherosclerosis: Reactive Dicarbonyls as Promising Targets of Therapy

Epidemiologic studies detected an inverse relationship between HDL (high-density lipoprotein) cholesterol (HDL-C) levels and atherosclerotic cardiovascular disease (ASCVD), identifying HDL-C as a major risk factor for ASCVD and suggesting atheroprotective functions of HDL. However, the role of HDL-C as a mediator of risk for ASCVD has been called into question by the failure of HDL-C-raising drugs to reduce cardiovascular events in clinical trials. Progress in understanding the heterogeneous nature of HDL particles in terms of their protein, lipid, and small RNA composition has contributed to the realization that HDL-C levels do not necessarily reflect HDL function. The most examined atheroprotective function of HDL is reverse cholesterol transport, whereby HDL removes cholesterol from plaque macrophage foam cells and delivers it to the liver for processing and excretion into bile. Indeed, in several studies, HDL has shown inverse associations between HDL cholesterol efflux capacity and ASCVD in humans. Inflammation plays a key role in the pathogenesis of atherosclerosis and vulnerable plaque formation, and a fundamental function of HDL is suppression of inflammatory signaling in macrophages and other cells. Oxidation is also a critical process to ASCVD in promoting atherogenic oxidative modifications of LDL (low-density lipoprotein) and cellular inflammation. HDL and its proteins including apoAI (apolipoprotein AI) and PON1 (paraoxonase 1) prevent cellular oxidative stress and LDL modifications. Importantly, HDL in humans with ASCVD is oxidatively modified rendering HDL dysfunctional and proinflammatory. Modification of HDL with reactive carbonyl species, such as malondialdehyde and isolevuglandins, dramatically impairs the antiatherogenic functions of HDL. Importantly, treatment of murine models of atherosclerosis with scavengers of reactive dicarbonyls improves HDL function and reduces systemic inflammation, atherosclerosis development, and features of plaque instability. Here, we discuss the HDL antiatherogenic functions in relation to oxidative modifications and the potential of reactive dicarbonyl scavengers as a therapeutic approach for ASCVD.

Association of APOE (rs429358 and rs7412) and PON1 (Q192R and L55M) Variants with Myocardial Infarction in the Pashtun Ethnic Population of Khyber Pakhtunkhwa, Pakistan

Coronary Artery Diseases (CAD) remains the top among Non-communicable Diseases (NCDs). Variations in Apolipoprotein E (APOE) and Paroxonase 1 (PON1) have been associated with Myocardial Infarction (MI) in several populations. However, despite the high prevalence of CAD, no such study has been reported in the Pashtun ethnic population of Pakistan. We have conducted a two-stage (i.e., screening and validation) case-control study in which 200 cases and 100 control subjects have been recruited. In the first stage, Whole Exome Sequencing (WES) was used to screen forpathogenic variants of Myocardial Infarction (MI). In the second stage, selected variants of both APOE and PON1 genes (rs7412, rs429358, rs854560, and rs662) were analyzed through MassARRAY genotyping. Risk Allele Frequencies (RAFs) distribution and association of the selected SNPs with MI were determined using the Chi-square test and logistic regression analysis. WES identified a total of 12 sequence variants in APOE and 16 in PON1. Genotyping results revealed that APOE variant rs429358 (ɛ4 allele and ɛ3/ɛ4 genotype) showed significant association in MI patients (OR = 2.11, p value = 0.03; 95% CI = 1.25–2.43); whereas no significant difference (p˃ 0.05) was observed for rs7412. Similarly, the R allele of PON1 Q192R (rs662) was significantly associated with cases (OR = 1.353, p value = 0.048; 95% CI = 0.959–1.91), with particular mention of RR genotype (OR = 1.523, p value = 0.006; 95% CI = 1.087–2.132). Multiple logistic regression analysis showed that rs429358 (C allele) and rs662 (R allele) have a significantly higher risk of MI after adjustment for the conventional risk factors. Our study findings suggested that the rs429358 variant of APOE and PON1 Q192R are associated with MI susceptibility in the Pashtun ethnic population of Pakistan.

The association of the paraoxonase 1 Q192R polymorphism with coronary artery disease (CAD) and cardiometabolic risk factors in Iranian patients suspected of CAD

Introduction

The present study aimed to investigate the association of the paraoxonase 1 (PON1) Q192R polymorphism with coronary artery disease (CAD) and cardiometabolic risk factors in Iranian patients suspected of CAD.

Methods

This cross-sectional study was conducted on 428 patients undergoing angiography. The data related to demographic information and physical activity were collected by valid and reliable questionnaires. The PON-1 genotypes were detected by the polymerase chain reaction-restriction fragment length polymorphism (RFLP-PCR) technique. The Gensini and SYNTAX score, anthropometric measurements, and biochemical and clinical parameters were measured by standard protocols.

Results and discussion

Findings indicated that the odds of obesity was significantly higher in people with the RR genotype compared to the QQ genotype carriers (OR: 2.95 CI: 1.25-6.93, P = 0.014) and also odds of low high-density lipoprotein cholesterol (HDL-C) was marginally higher (OR: 2.31 CI: 0.97-5.49, P = 0.056). There was no significant association between other CAD risk factors with PON1 Q192R polymorphism (P > 0.05). Further analysis showed a significant interaction between sex and 192QR (P = 0.019) and 192 RR (P = 0.007) genotypes on body mass index (BMI). More specifically, the risk of obesity in men carrying the RR genotype was 3.38 times (OR: 3.38 CI: 1.08-10.58, P = 0.036). Also, a significant joint effect of the RR genotype and sex on HDL-C was seen (P = 0.003). The stratification based on sex showed that the risk of low HDL-C is significantly higher in women carrying the RR genotype (OR: 6.18 CI: 1.21-31.46, P = 0.028). A marginal sex-genotype interaction was also found in the risk of elevated alanine aminotransferase (ALT) (P = 0.057). In summary, the findings showed that the risk of obesity and low HDL-C was higher in people carrying the RR genotype. On the other hand, a Q192R polymorphism-sex interaction was observed on the risk of obesity, elevated ALT, and low HDL-C.

Paraoxonase gene polymorphisms: Understanding the biochemical and genetic basis of coronary artery disease

Objectives

Serum paraoxonase (PON) is a glycoprotein with antioxidant and anti-atherosclerotic activities. The Q192R and L55M gene polymorphisms of PON have been implicated as risk factors for coronary artery disease (CAD) but have not been extensively explored in South Indians. We aimed to assess the Q192R and L55M genetic polymorphisms of the PON1 gene in participants with CAD, including genotypes and allele frequencies for PON1 gene polymorphism.

Methods

This prospective case-control study involved 20 participants in each group. Patients with angiographically demonstrated CAD were included in the case group. PON1 activity was measured, and PON gene polymorphism was determined. Serum PON was quantitatively analyzed with a RayBio® Human PON1 ELISA kit. Chi square tests were used to assess the association of the genotypes with sex and any comorbidities in cases and controls. A p value ≤ 0.05 was considered significant.

Results

Mutant type L55M polymorphism was observed in 50% of patients, whereas wild type Q192R polymorphism was observed in 42.5% of the participants. The mean PON values between groups did not significantly differ, whereas PON U/L was significantly (p = 0.001) lower in the case group. The L55M polymorphism did not significantly differ between the case and the control groups (p = 0.213), whereas the Q192R polymorphism was statistically significant in cases compared with controls (p ≤ 0.001).

Conclusion

Low plasma PON1 and HDL levels, and higher LDL, total cholesterol and triglyceride levels were observed in patients with CAD. More patients with CAD than healthy individuals had Q192R polymorphism.

Impact of oxidative stress SNPs on sperm DNA damage and male infertility in a south-east Iranian population

AIM

We examined four single nucleotide polymorphisms in four antioxidant genes (PON1 , CAT , GPx1 and SOD2 ) in 100 infertility cases and 100 controls from an Iranian population-based case-control study to confirm the assumption that polymorphisms in oxidative stress genes increase the risk of sperm DNA damage and idiopathic male infertility.

METHODS

Restriction fragment length polymorphism and tetra-primer amplification refractory mutation system PCR were used to identify genotypes. Sperm DNA damage was assessed using the Sperm Chromatin Dispersion test (Halo Sperm), and the total antioxidant capacity of seminal fluid was determined using the FRAP assay.

KEY RESULTS

Our findings demonstrated that alleles Arg-PON1 (rs662) and Ala-MnSOD (rs4880) variant genotypes were considerably linked with a higher risk of male infertility.

CONCLUSIONS

Linear regression analysis revealed that those with the PON1 Gln192Arg or SOD2 Val16Ala variants have significantly higher levels of sperm DNA fragmentation and lower levels of the total antioxidant capacity in seminal fluid.

IMPLICATIONS

These findings suggest that genetic differences in antioxidant genes may be linked to oxidative stress, sperm DNA damage, and idiopathic male infertility.

Paraoxonase 2 C311S single nucleotide polymorphism is associated with type C lesions in coronary atherosclerosis

BACKGROUND

Paraoxonases (PON) 1-3 are lactonases with antioxidant and atheroprotective properties. The best known single nucleotide polymorphisms (SNPs) within the PON family, include: Q192R (rs662), L55M (rs854560) in the PON1 gene and C311S (rs7493) in the PON2 gene. Their influence on the occurrence and course of coronary artery disease (CAD) is unclear. The aim of this study was to assess the association between the most common PON1 and PON2 genetic variants with the presence of CAD, as well as their relation to coronary lesion complexity in accordance with the ACC/AHA standard.

METHODS

We included 1027 individuals: 367 CAD patients qualified for coronary angiography and 660 healthy volunteers as controls. We extracted DNA from circulating blood leukocytes, amplified the PON1 and PON2 genetic sequence and used restriction enzymes to identify the SNPs. Patients with CAD underwent coronary angiography and were assigned to two groups based on lesion severity: patients with at least one type C lesion and without a type C lesion. The former where categorized into those with a significant narrowing (≥50% diameter stenosis) and those without one.

RESULTS

We found no association between the analyzed SNPs and symptomatic CAD. However, in patients with diagnosed CAD, the PON311S allele was independently associated with the risk of the most complex type C coronary lesion occurrence.

CONCLUSIONS

Our study is the first report of an association between PON2 311S SNP and the type of coronary atherosclerotic lesions in humans.

Paraoxonase-1 (PON-1) Arylesterase Activity Levels in Patients with Coronary Artery Disease: A Meta-Analysis

Aim

To review and compare the PON-1 arylesterase activity between coronary artery disease (CAD) and non-CAD patients.

Methods

Data were obtained by searching MEDLINE and Scopus for all investigations published between January 1, 2000 and March 1, 2021 comparing PON-1 arylesterase activity between CAD and controls.

Results

Twenty studies, based on 5417 patients, met the inclusion criteria and were included in the analysis. A random effect model revealed that PON-1 arylesterase activity was significantly lower in the CAD group compared to controls (SMD = -0.587, 95%CI = -0.776 to -0.339, p < 0.0001, I 2 = 92.3%). In CAD patients, the PON-1 arylesterase activity was significantly higher among CAD patients without diabetes mellitus (DM) compared to those with diabetes (SMD: 0.235, 95% CI: 0.014 to 0.456, p = 0.03, I 2 = 0%).

Conclusions

PON-1 activity is significantly lower in CAD patients, and those without DM presented a significantly higher PON-1 arylesterase activity.

Myeloperoxidase-induced modification of HDL by isolevuglandins inhibits paraoxonase-1 activity

Reduced activity of paraoxonase 1 (PON1), a high-density lipoprotein (HDL)-associated enzyme, has been implicated in the development of atherosclerosis. Post-translational modifications of PON1 may represent important mechanisms leading to reduced PON1 activity. Under atherosclerotic conditions, myeloperoxidase (MPO) is known to associate with HDL. MPO generates the oxidants hypochlorous acid and nitrogen dioxide, which can lead to post-translational modification of PON1, including tyrosine modifications that inhibit PON1 activity. Nitrogen dioxide also drives lipid peroxidation, leading to the formation of reactive lipid dicarbonyls such as malondialdehyde and isolevuglandins, which modify HDL and could inhibit PON1 activity. Because isolevuglandins are more reactive than malondialdehyde, we used in vitro models containing HDL, PON1, and MPO to test the hypothesis that IsoLG formation by MPO and its subsequent modification of HDL contributes to MPO-mediated reductions in PON1 activity. Incubation of MPO with HDL led to modification of HDL proteins, including PON1, by IsoLG. Incubation of HDL with IsoLG reduced PON1 lactonase and antiperoxidation activities. IsoLG modification of recombinant PON1 markedly inhibited its activity, while irreversible IsoLG modification of HDL before adding recombinant PON1 only slightly inhibited the ability of HDL to enhance the catalytic activity of recombinant PON1. Together, these studies support the notion that association of MPO with HDL leads to lower PON1 activity in part via IsoLG-mediated modification of PON1, so that IsoLG modification of PON1 could contribute to increased risk for atherosclerosis, and blocking this modification might prove beneficial to reduce atherosclerosis.

The Relevance of Noncoding DNA Variations of Paraoxonase Gene Cluster in Atherosclerosis-Related Diseases

The human paraoxonase (PON) gene cluster is comprised of three contiguous genes (PON1, PON2 and PON3) of presumably common origin coding three lactonases of highly similar structure and substrate specificity. The catalytic activity of PON proteins is directed toward artificial organophosphates and in physiological conditions toward thiolactones and oxidized phospholipids. Consequently, PON enzymes are regarded as an effective defense against oxidative stress and, as a result, against atherosclerosis development. Additionally, both PON's serum activity and its concentration are influenced by several polymorphic variations in coding and noncoding DNA regions of the PON gene cluster remaining in linkage disequilibrium. Hence, the genetic polymorphism of the PON gene cluster may contribute to atherosclerotic process progression or deceleration. In this review the authors analyzed the relevance of noncoding DNA polymorphic variations of PON genes in atherosclerosis-related diseases involving coronary and peripheral artery disease, stroke, diabetes mellitus, dementia and renal disease and concluded that the effect of PON gene cluster' polymorphism has a considerable impact on the course and outcome in these conditions. The following PON genetic variations may serve as additional predictors of the risk of atherosclerosis in selected populations and individuals.

The Role of Paraoxonase 1 (PON1) Gene Polymorphisms in Coronary Artery Disease: A Systematic Review and Meta-Analysis

Although many studies have investigated the association of paraoxonase 1 (PON1) polymorphisms with coronary artery disease (CAD). However, the outcomes were not consistent and remain uncertain. Therefore, it is the need of the hour to analyze the available literature and evaluate the association of PON1 polymorphisms with the CAD. All the relevant studies published in the English language from January 1, 2000, up to September 20, 2020, were identified by searching through various electronic databases. The two researchers independently extracted the information. The data were analyzed by using the MetaGenyo program. The pooled odds ratio was used to find the associations between CAD and PON1 polymorphisms. In the final analysis, we include 10 studies regarding the association of PON1 polymorphisms (rs662 and rs854560) with CAD. Overall, the Q192R polymorphism increased the risk of CAD in the tested genetic models including the homozygote model: OR 1.35, CI 1.02-1.79; allelic model: OR 1.16, CI 1.00-1.33; dominant model: OR 1.25, CI 1.03-1.52. The L55M polymorphism does not significantly associated with CAD in all the tested genetic models including the homozygote model: OR 1.00 CI, 0.64-1.56; allelic model: OR 1.02, 95% CI 0.84-1.23; dominant model: OR 1.08, CI 0.89-1.31. Further analysis showed no publication bias exists in meta-analysis. Our findings suggested that rs662 in the coding region was significantly associated with the CAD however, rs854560 has no significant association with the disease. Nevertheless, in future, there is a need for more studies with a larger sample size which may provide a more definite conclusion.Study Registration: PROSPERO registration number CRD42020202278.