Paraoxonase 1 and 2 gene variants and the ischemic stroke risk in Gran Canaria population: an association study and meta-analysis

Association of Paraoxonase-2 (C1053G) Gene Polymorphism with the Expression of Paraoxonase-2 Gene in Patients of Ischemic Stroke - A Pilot Study in Indian Population

Background and Objective

Oxidative stress plays an important role in atherosclerosis and ischemic stroke. Due to antioxidant properties of Paraoxonase-2, we studied the implication of Paraoxonase-2 gene polymorphism (C1053G) on expression of Paraoxonase-2 gene at mRNA level in ischemic stroke patients.

Material and Methods

40 patients of ischemic stroke and 40 age and sex-matched controls were included. Paraoxonase-2 genotypes were evaluated by Polymerase Chain Reaction and Restriction Fragment Length Polymorphism and expression of Paraoxonase-2 gene at mRNA level was determined by quantitative real time Polymerase Chain Reaction analysed as delta-CT (△CT).

Result and Discussion

The observed allele frequencies in patients for C and G allele were 0.61 and 0.39 respectively, and were 0.72 and 0.28 in control group. No significant association was found in C allele of C1053G polymorphism and ischemic stroke. The average △ CT value is significantly (p = 0.0001) higher in patients group (7.68 ± 2.0) as compared to controls (5.70 ± 1.8). We found a significant difference in the average delta-CT value (p = 0.0001), wherein down-regulated paraoxonase-2 gene expression (approximately 0.25 fold) was observed in case of patients as compared to controls. Down-regulated expression of paraoxonase-2 gene was observed in patients with GG genotype as compared to CG and CC genotypes in patients with ischemic stroke (p = 0.0001).

Conclusion

Down-regulated Paraoxonase-2 gene expression, as evidenced by low mRNA levels in GG genotype may be one of the contributory factors in the progression of ischemic stroke.

Association of PON-1 polymorphism with susceptibility to and severity of ischemic stroke in the Chinese population

Aim: The authors aimed to investigate whether polymorphisms of PON-1 were associated with the susceptibility to and severity of ischemic stroke (IS). Methods: In this study, 302 IS patients and 303 healthy controls were enrolled. Polymorphisms rs854560 and rs854572 of PON-1 were detected using SNaPshot single-nucleotide polymorphism typing technology. Results: The rs854572 polymorphism of the PON-1 gene showed a significant correlation with IS, and its GG genotype reduced the risk of IS (recessive model, p = 0.001). The GG genotype was also associated with mild stroke (p = 0.032). No association was observed between rs854560 and IS. Conclusion: PON-1 rs854572 polymorphism was related to the risk of IS and could be a biomarker to access the severity of IS.

Proteomics-Based Approach to Identify Novel Blood Biomarker Candidates for Differentiating Intracerebral Hemorrhage From Ischemic Stroke-A Pilot Study

Background: A reliable distinction between ischemic stroke (IS) and intracerebral hemorrhage (ICH) is required for diagnosis-specific treatment and effective secondary prevention in patients with stroke. However, in resource-limited settings brain imaging, which is the current diagnostic gold standard for this purpose, is not always available in time. Hence, an easily accessible and broadly applicable blood biomarker-based diagnostic test differing stroke subtypes would be desirable. Using an explorative proteomics approach, this pilot study aimed to identify novel blood biomarker candidates for distinguishing IS from ICH.

Material and Methods: Plasma samples from patients with IS and ICH were drawn during hospitalization and were analyzed by using liquid chromatography/mass spectrometry. Proteins were identified using the human reference proteome database UniProtKB, and label-free quantification (LFQ) data were further analyzed using bioinformatic tools.

Results: Plasma specimens of three patients with IS and four patients with ICH with a median National Institute of Health Stroke Scale (NIHSS) of 12 [interquartile range (IQR) 10.5–18.5] as well as serum samples from two healthy volunteers were analyzed. Among 495 identified protein groups, a total of 368 protein groups exhibited enough data points to be entered into quantitative analysis. Of the remaining 22 top-listed proteins, a significant difference between IS and ICH was found for Carboxypeptidase N subunit 2 (CPN2), Coagulation factor XII (FXII), Plasminogen, Mannan-binding lectin serine protease 1, Serum amyloid P-component, Paraoxonase 1, Carbonic anhydrase 1, Fibulin-1, and Granulins.

Discussion: In this exploratory proteomics-based pilot study, nine candidate biomarkers for differentiation of IS and ICH were identified. The proteins belong to the immune system, the coagulation cascade, and the apoptosis system, respectively. Further investigations in larger cohorts of patients with stroke using additional biochemical analysis methods, such as ELISA or Western Blotting are now necessary to validate these markers, and to characterize diagnostic accuracy with regard to the development of a point-of-care-system for use in resource-limited areas.

PON1 (Paraoxonase 1) Q192R gene polymorphism in ischemic stroke among North Indian population

Background:

PON1 is an High Density Lipoprotein (HDL)-associated esterase. Two common polymorphisms in the PON1 gene, Q192R and L55M substitutions, determine the inter-individual variation in PON1 activity. The association of these polymorphisms with the risk of ischemic stroke remains controversial. In the present study, the role of PON1 Q192R gene polymorphism in ischemic stroke was studied in the Indian population.

Design and Methods:

In the present case-control study, the PON1 Q192R gene polymorphism was screened in ischemic stroke patients (n: 63) and age, sex-matched controls (n: 63) using thePolymerase Chain Reaction-Restriction Segment Length Polymorphism (PCR-RFLP) method.

Results:

The mean age of stroke presentation was 58.11 ± 15.4 years. A total of 17.4% cases presented with young stroke (<45 years age) and 9.52% cases were seen to have a recurrent stroke. The distribution of -192Q/R PON1 gene polymorphism was not seen to differ between cases and controls. The traditional stroke risk factors did not have any effect on the PON1 genotype expression. A multivariate logistic regression analysis was done in order to assess an independent association of age, gender, traditional stroke risk factors, and PON1 polymorphism with acute ischemic stroke. However, neither the RR genotype nor the presence of the R allele was associated with an increase in the risk of acute ischemic stroke (OR [RR genotype]-4.76, P value: 0.24, 95% CI: 0.3497–64.8531; OR [R allele]-0.94, P value: 0.90, 95% CI: 0.3516–2.4989).

Conclusion:

PON1 Q192R gene polymorphism is not associated with an increased risk of acute ischemic stroke in the North Indian population. Further studies with a larger sample size are needed before PON1 Q192R gene polymorphism can be considered as a genetic risk factor for ischemic stroke.

Human Paraoxonase-2 (PON2): Protein Functions and Modulation

PON1, PON2, and PON3 belong to a family of lactone hydrolyzing enzymes endowed with various substrate specificities. Among PONs, PON2 shows the highest hydrolytic activity toward many acyl-homoserine lactones (acyl-HL) involved in bacterial quorum-sensing signaling. Accordingly, defense against pathogens, such as Brevundimonas aeruginosa (B. aeruginosa), was postulated to be the principal function of PON2. However, recent findings have highlighted the importance of PON2 in oxidative stress control, inhibition of apoptosis, and the progression of various types of malignancies. This review focuses on all of these aspects of PON2.

The Antioxidant Enzyme PON1: A Potential Prognostic Predictor of Acute Ischemic Stroke

Objective

Paraoxonase 1 (PON1) is an antioxidant enzyme, which has been proved to be involved in the pathophysiological process of oxidative stress and various neurological diseases in recent years. Although reduced PON1 activity has been reported in patients with acute ischemic stroke (AIS), the prognostic value of PON1 in AIS has not been clearly established. The purpose of this study was to determine whether the baseline serum PON1 activity level is related to the functional outcome of AIS patients.

Methods

From July 2017 to June 2020, AIS patients within 3 days of symptom onset were continuously prospectively included in the study. On admission, clinical and laboratory data were recorded, and serum PON1 activity was tested. The National Institute of Health Stroke Scale (NIHSS) score was used to evaluate the initial neurologic deficit at admission, and the modified Rankin scale (mRS) was used to evaluate the functional outcome at 3 months. A multiple logistic regression model was used to analyze the relationship between the baseline PON1 activity level and the prognosis of AIS.

Results

A total of 336 AIS patients were finally included in this study. The serum PON1 activity of AIS patients with good outcomes was significantly higher than that of patients with poor outcomes (193.4 ± 16.3 U/mL vs. 127.2 ± 14.9 U/mL, p < 0.001). However, the comparison of other clinical and laboratory data between AIS patients with good and poor outcomes was not significant (p > 0.05). There was a significant decrease in the mRS score in patients with AIS across serum PON1 quartiles (3.0 ± 1.6, 2.6 ± 1.5, 2.4 ± 1.4, and 2.4 ± 1.3, p = 0.007). Multivariate logistic regression analysis showed that the 3-month functional outcome of AIS patients was significantly correlated with the quartile of serum PON1 activity.

Conclusions

This study suggests that the serum PON1 activity may be an independent predictor of the functional outcome of AIS patients.

Susceptibility of PON1/PON2 Genetic Variations to Ischemic Stroke Risk in a Chinese Han Population

Background

Paraoxonases (PONs) are a family of orphan enzymes with multiple functions, including anti-inflammatory, antioxidative, antiatherogenic activities. Studies have suggested that genetic variations in PON1 and PON2 are associated with ischemic stroke (IS) risk; however, the conclusion remains unclear in the Chinese population.

Methods

To investigate the susceptibility of genetic variations in PON1 and PON2 to risk of IS and its subtypes, this case–control study was carried out on a Chinese population comprising 300 IS patients and 300 healthy controls. Genotypes of six genetic variations in PON1 and PON2 were identified with an improved multiplex ligase detection–reaction technique.

Results

PON1 rs662 was associated with increased risk of IS (CT vs. TT — OR_adjusted 1.79, 95% CI 1.08–2.97; p=0.025). Stratified analysis for patients by sex revealed that the significant association of PON1 rs662 with IS risk was maintained in the male cohort (CT vs. TT — OR_adjusted 2.59, 95% CI 1.29–5.21 [p=0.009]; CT/CC vs. TT — OR_adjusted 2.03, 95% CI 1.05–3.93 [p=0.036]), but not in the female cohort. Analysis according to IS subtype revealed that PON1 rs662 genetic variation was an increased risk in the subcohort of patients with large-artery atherosclerosis (CT/CC vs. TT — OR_adjusted 2.31, 95% CI 1.09–4.91; p=0.029), but not in patients with other types of IS.

Conclusion

This study suggested that PON1 rs662 presented a potential risk of IS, especially for males, and this association was more obvious for large-artery atherosclerosis.

Association of SOD2 A16V and PON2 S311C polymorphisms with polycystic ovary syndrome in Chinese women

PURPOSE

To investigate the relationship between superoxide dismutase 2 (SOD2) A16V and paraoxonase 2 (PON2) S311C gene variants and the risk of polycystic ovary syndrome (PCOS) and evaluate the effects of the genotypes on clinical, hormonal, metabolic and oxidative stress indexes in Chinese women.

METHODS

This is a cross-sectional study of 932 patients with PCOS and 745 control women. For the clinical and metabolic association study of genotypes, 631 patients and 492 controls were included after excluding the subjects with interferential factors. Genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis. Serum total oxidant status, total antioxidant capacity (T-AOC), oxidative stress index and malondialdehyde (MDA) levels, and clinical and metabolic parameters were also analyzed.

RESULTS

The prevalence of the A allele of SOD2 A16V polymorphism was significantly greater in patients with PCOS than in control subjects. Genotype (AA + AV) remained a significant predictor for PCOS in prognostic models including age, body mass index, insulin resistance index, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides (TGs) as covariates. Patients carrying the A allele had significantly higher serum luteinizing hormone (LH) levels, and the ratio of LH to follicle-stimulating hormone compared with patients with the VV genotype. We also showed that patients carrying the C allele of the PON2 S311C polymorphism had lower T-AOC compared with patients carrying the SS genotype. However, no significant differences were observed in the frequencies of the S311C genotypes and alleles of the PON2 gene between PCOS and control groups.

CONCLUSION

The SOD2 A16V, but not PON2 S311C, polymorphism may be one of the genetic determinants for PCOS in Chinese women.

Genomic Analyses of Human European Diversity at the Southwestern Edge: Isolation, African Influence and Disease Associations in the Canary Islands

Despite the genetic resemblance of Canary Islanders to other southern European populations, their geographical isolation and the historical admixture of aborigines (from North Africa) with sub-Saharan Africans and Europeans have shaped a distinctive genetic makeup that likely affects disease susceptibility and health disparities. Based on single nucleotide polymorphism array data and whole genome sequencing (30×), we inferred that the last African admixture took place ∼14 generations ago and estimated that up to 34% of the Canary Islander genome is of recent African descent. The length of regions in homozygosis and the ancestry-related mosaic organization of the Canary Islander genome support the view that isolation has been strongest on the two smallest islands. Furthermore, several genomic regions showed significant and large deviations in African or European ancestry and were significantly enriched in genes involved in prevalent diseases in this community, such as diabetes, asthma, and allergy. The most prominent of these regions were located near LCT and the HLA, two well-known targets of selection, at which 40‒50% of the Canarian genome is of recent African descent according to our estimates. Putative selective signals were also identified in these regions near the SLC6A11-SLC6A1, KCNMB2, and PCDH20-PCDH9 genes. Taken together, our findings provide solid evidence of a significant recent African admixture, population isolation, and adaptation in this part of Europe, with the favoring of African alleles in some chromosome regions. These findings may have medical implications for populations of recent African ancestry.

Shared genetic risk factors for depression and stroke

BACKGROUND

The comorbidity of major depressive disorder (MDD) and stroke are common in clinic. There is a growing body of evidence suggesting a bi-directional relationship between stroke and depression. However, the mechanisms underlying the relationship between MDD and stroke are poorly investigated. Considering that both MDD and stroke can be heritable and are influenced by multiple risk genes, shared genetic risk factors between MDD and stroke may exist.

OBJECTIVE

The objective is to review the existing evidence for common genetic risk factors for both MDD and stroke and to outline the possible pathophysiological mechanisms mediating this association.

METHODS

A systematic review and meta-analysis was performed. Gene association studies regarding stroke and depression were searched in the database PubMed, CNKI, and Chinese Biomedical Literature Database before December 2018. Statistical analysis was performed using the software Revman 5.3.

RESULTS

Genetic polymorphisms of 4 genes, methylenetetrahydrofolate reductase (MTHFR) and apolipoprotein E (ApoE) have been demonstrated to associate with the increased risk for both MDD and stroke, while the association between identified polymorphisms in angiotensin converting enzyme (ACE) and serum paraoxonase (PON1) with depression is still under debate, for the existing studies are insufficient in sample size. These results suggest the possible pathophysiological mechanisms that are common to these two disorders, including immune-inflammatory imbalance, increased oxidative and nitrative stress, dysregulation of lipoprotein and lipid metabolism, and changes of cerebrovascular morphology and function. Other associated genes with few or conflicting results have also been included, and a few studies have investigated the effects of the described polymorphisms on MDD and stroke comorbidity, such as post stroke depression.

CONCLUSION

These findings suggest that shared genetic pathways may contribute to the comorbidity of MDD and stroke. Studies to evaluate the shared genetic variations between MDD and stroke may provide insights into the molecular mechanisms that trigger disease progression.

A meta-analysis on relationship between paraoxonase 1 polymorphisms and atherosclerotic cardiovascular diseases

BACKGROUND

Some previous studies already explored associations between paraoxonase 1 (PON1) polymorphisms and atherosclerotic cardiovascular diseases (ASCVD), with conflicting findings. Here, we aimed to better analyze the relationship between PON1 polymorphisms and ASCVD in a larger combined population by performing a meta-analysis.

METHODS

We searched Pubmed, Embase and Web of Science for related articles. We calculated odds ratio (OR) and 95% confidence interval (CI) to estimate whether there are genetic associations between PON1 polymorphisms and ASCVD.

RESULTS

One hundred and nine studies were included for this meta-analysis. The PON1 rs854560 (17,220 cases and 18,570 controls, recessive comparison: OR = 0.83, 95%CI 0.72-0.96) and rs662 (30,717 cases and 54,894 controls, dominant comparison: OR = 0.82, 95% CI 0.77-0.89; recessive comparison: OR = 1.17, 95% CI 1.07-1.28; allele comparison: OR = 0.85, 95% CI 0.81-0.90) polymorphisms were both found to be significantly associated with susceptibility to ASCVD in general population. Subgroup analyses by ethnicity revealed similar significant findings for rs854560 polymorphism only in East Asians, while similar positive findings for rs662 polymorphism were observed in Caucasians, East Asians and South Asians. Subgroup analyses by type of disease indicated that the significant findings for rs854560 polymorphism were mainly driven by the ischemic stroke (IS) subgroup, whereas the positive results for rs662 polymorphism were mainly driven by the coronary artery disease (CAD) subgroup.

CONCLUSIONS

In summary, this meta-analysis proved that PON1 rs854560 polymorphism could be used to identify individual with elevated susceptibility to IS, whereas rs662 polymorphism could be used to identify individual with elevated susceptibility to CAD.

Paraoxonase 2 protects against acute myocardial ischemia-reperfusion injury by modulating mitochondrial function and oxidative stress via the PI3K/Akt/GSK-3β RISK pathway

OBJECTIVE

To investigate the novel role of Paraoxonase 2 (PON2) in modulating acute myocardial ischemia-reperfusion injury (IRI).

APPROACH

IRI was induced both in vivo and ex vivo in male, C57BL6/J (WT) and PON2-deficient (PON-def) mice. In addition, in vitro hypoxia-reoxygenation injury (HRI) was induced in H9c2 cells expressing empty vector (H9c2-EV) or human PON2 (H9c2-hPON2) ± LY294002 (a potent PI3K inhibitor). Infarct size, PON2 gene expression, mitochondrial calcium retention capacity (CRC), reactive oxygen species (ROS) generation, mitochondrial membrane potential, CHOP and pGSK-3β protein levels, and cell apoptosis were evaluated.

RESULTS

PON2 gene expression is upregulated in WT mice following in vivo IRI. PON2-def mice exhibit a 2-fold larger infarct, increased CHOP levels, and reduced pGSK-3β levels compared to WT controls. Global cardiac mitochondria isolated from PON2-def mice exhibit reduced CRC and increased ROS production. Cardiomyocytes isolated from PON2-def mice subjected to ex vivo IRI have mitochondria with reduced CRC (also seen under non-IRI conditions), and increased ROS generation and apoptosis compared to WT controls. PON2 knockdown in H9c2 cells subjected to HRI leads to an increase in mitochondrial membrane depolarization. H9c2-hPON2 cells exhibit i) improvement in mitochondrial membrane potential, pGSK-3β levels and mitochondrial CRC, and ii) decrease in CHOP levels, mitochondrial ROS generation and cell apoptosis, when compared to H9c2-EV controls. Treatment with LY294002 resulted in a decrease of mitochondrial CRC and increase in mitochondrial ROS production and cell apoptosis in the H9c2-hPON2 group versus H9c2-EV controls.

CONCLUSION

PON2 protects against acute myocardial IRI by reducing mitochondrial dysfunction and oxidative stress in cardiomyocytes via activation of the PI3K/Akt/GSK-3β RISK pathway.

Association of PON2 Gene Polymorphisms (Ser311Cys and Ala148Gly) With the Risk of Developing Type 2 Diabetes Mellitus in the Chinese Population

Background: The association between paraoxonase 2 (PON2) gene polymorphisms and type 2 diabetes mellitus (T2DM) has been extensively investigated in the Chinese population with conflicting results. In this study, we systematically evaluated the association between PON2 Ser311Cys and Ala148Gly polymorphisms and T2DM risk by pooling all relevant studies. Methods: We searched PubMed, Embase, CNKI, and Wanfang databases for the studies. The strength of association was determined by the allelic, homozygous, heterozygous, recessive, and dominant genetic models and measured as odds ratio (OR) and 95% confidence interval (CI), under fixed- or random-effect models. Results: There was no significant association between PON2 Ser311Cys polymorphism and T2DM under any of the genetic models: allelic (OR = 1.06, 95% CI = 0.77-1.45; P = 0.721), heterozygous (OR = 1.13, 95% CI = 0.87-1.45; P = 0.362), dominant (OR = 1.10, 95% CI = 0.80-1.51; P = 0.562), recessive (OR = 0.87, 95% CI = 0.48-1.58; P = 0.648), homozygous (OR = 0.94, 95% CI = 0.47-1.89; P = 0.865). Similarly, no significant association was found in PON2 Arg148Gly polymorphism under any of the models: allelic (OR = 1.17, 95% CI = 0.91-1.50; P = 0.218), heterozygous (OR = 1.28, 95% CI = 0.94-1.74; P = 0.117), dominant (OR = 1.25, 95% CI = 0.93-1.67; P = 0.142), recessive (OR = 0.99, 95% CI = 0.52-1.88; P = 0.973), homozygous (OR = 1.08, 95% CI = 0.57-2.07; P = 0.808). Conclusions: The PON2 Ser311Cys and Ala148Gly polymorphisms were not associated with the risk of developing T2DM in the Chinese population.