Functional implications of single nucleotide polymorphisms rs662 and rs854860 on the antioxidative activity of paraoxonase1 (PON1) in patients with rheumatoid arthritis

Association of paraoxonase-1 (Q192R) gene polymorphism with coronary artery spasm during cardiac catheterisation in Egyptians

BACKGROUND

Coronary artery spasm is among the etiology of myocardial infarction. Oxidative stress is involved in the pathogenesis of coronary artery spasm (CAS). Paraoxonase-1 (PON1) is an HDL-bound antioxidant enzyme that protects LDL from oxidative modification. Oxidative-stress-related genetic factors and certain polymorphisms in the paraoxonase 1 gene might influence the pathogenesis of CAS. We aimed to investigate the association between PON1 gene polymorphism and its enzymatic activity and coronary artery spasm during cardiac catheterization.

METHODS AND RESULTS

The study population was 150 patients who underwent elective coronary angiography. Subjects were genotyped to the Q192R polymorphism (rs662) on the PON1 gene by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and PON1 activity was quantitatively analyzed by enzyme linked immunosorbent assay. Results showed that the subjects carrying the RR genotype and R allele were significantly more likely to develop coronary artery spasm (OR=4.2, 2.03, P< 0.006, P˂0.02, respectively). Moreover, serum PON1 levels were significantly decreased (P˂0.001) in the CAS group. RR genotype of PON1 Q192R polymorphism, Tc, LDLc, TG, catheter size, and paroxonase-1 serum level are independent predictors of coronary spasm.

CONCLUSION

We conclude that the PON1 (rs662) gene polymorphism is associated with CAS during cardiac catheterization in Egyptians. The PON1-192R allele and lower serum enzyme concentration may play an important role in coronary spasm.

Association between Paraoxonase/Arylesterase Activity of Serum PON-1 Enzyme and Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

Background: A decrease in serum paraoxonase (PON-1) and arylesterase (ARE) activity has been reported in rheumatoid arthritis (RA) patients and linked to chronic inflammation and impaired antioxidant defense. Methods: A systematic review and meta-analysis were performed to critically appraise the current evidence on plasma/serum concentrations of PON-1 and ARE activity in RA patients and healthy controls. The Web of Science, PubMed, Scopus, and Google Scholar databases were searched from inception to November 2021. We used random-effects meta-analysis. The risk of bias was estimated using the Joanna Briggs Institute Critical Appraisal Checklist tool. The certainty of the evidence was assessed with GRADE. The study complied with the PRISMA statements and was registered in PROSPERO (CRD42022345380). Results: Seventeen studies reported PON-1 activity (1144 RA patients, 797 controls) and ten reported ARE activity (1367 RA patients, 1037 controls). RA patients had significantly lower PON-1 (SMD = −1.32, 95% CI −1.94 to −0.70; p < 0.001) and ARE activity (SMD = −0.91, 95% CI −1.37 to −0.46; p < 0.001). There was substantial heterogeneity (PON, I2 97%; ARE, 95.7%, p < 0.001 for both). There was no publication bias. The pooled SMD values did not significantly change after sensitivity analysis. The certainty of the evidence was very low due to the observational nature of the studies and the large heterogeneity. Conclusion: Our meta-analysis has shown that both serum PON-1 and ARE activity are significantly lower in RA patients, suggesting a deficit in antioxidant defense mechanisms in this disease.

Osteoprotegerin and MTHFR gene variations in rheumatoid arthritis: association with disease susceptibility and markers of subclinical atherosclerosis

We aimed to explore whether the rs2073618 variant (G1181C) of the osteoprotegerin (OPG) gene and the methylenetetrahydrofolate reductase (MTHFR) rs1801131 (A1298AC) and rs1801133 (C677T) gene polymorphisms contribute to rheumatoid arthritis (RA) susceptibility and RA related subclinical atherosclerosis. Overall 283 RA patients and 595 healthy controls (HC) were genotyped for common variants of the OPG and MTHFR genes using PCR based assays. Clinical and laboratory parameters were recorded following thorough chart review. Surrogate markers of subclinical atherosclerosis (Carotid/Femoral intima media thickness/plaque formation) along with traditional risk factors for atherosclerosis were assessed in all RA patients and 280HC. Increased prevalence of the CC genotype of the rs2073618 variant was detected in RA patients vs HC (42.4% vs. 33%, p-value: 0.04). RA patients with high serum titers of rheumatoid factor (RF) or anti-cyclic citrullinated peptide (CCP) antibodies displayed increased prevalence of the CC genotype of the rs2073618 variant of the OPG gene compared to HC (48.6% and 47.5 vs 33.3%, p-values: 0.0029and 0.0077 respectively). Of interest, this genotype turned to be associated with higher carotid IMT scores (0.872 ± 0.264 vs 0.816 ± 0.284, p-value: 0.01) and marginally with higher rates of carotid plaque formation (66% vs 54.1%, p = 0.06). The MTHFR 1298CC genotype was more prevalent only in the anti-CCP positive group compared to HC, with no associations detected with markers of subclinical atherosclerosis, following adjustment for traditional cardiovascular (CVD) risk factors. Reduced rates of carotid/femoral plaque formation were detected among RA patients harboring the MTHFR TT genotype (52.4 vs 72.7, p-value: 0.009, respectively). This association remained significant following adjustment for classical CVD risk factors (OR [95% CI 0.364 [0.173–0.765], p-value: 0.008). Genetic variations of the osteoprotegerin and MTHFR genes seem to increase susceptibility for seropositive RA and potentially contribute to subclinical atherosclerosis linked to RA. Larger studies are needed to confirm these findings.

Association between PON1 rs662 gene polymorphism and serum paraoxonase1 level in coronary artery disease patients in Northern India

Background

Coronary artery disease (CAD) is a leading cause of morbidity and mortality, with a shifting trend towards the younger population. Paraoxonase1 (PON1) is a glycoprotein enzyme associated with high-density lipoprotein (HDL) particles in the blood. It has the ability to protect against lipid oxidation, thereby reducing the risk of atherogenesis. PON1 rs662 gene polymorphism may affect serum PON1 levels as well as its activity and may have a significant role in the pathogenesis of CAD. The present study was conducted to identify the association of PON1 rs662 gene polymorphism with serum PON1 levels in CAD patients in the North Indian population. This case–control study included 71 angiography-proven CAD patients (with > 50% luminal stenosis in one or more coronary arteries) and 71 controls (with < 50% luminal obstruction in angiography). PON1 rs662 gene polymorphism was studied using PCR and RFLP under the standardized protocol. Serum PON1 levels were estimated by ELISA.

Results

The serum PON1 level was significantly lower in the CAD group than in the controls (7.79 ± 3.16 vs. 10.79 ± 3.19 ng/mL; p < 0.0001). Logistic regression analysis showed that homozygous GG genotype of PON1 rs662 SNP has ninefold increased risk of developing CAD in an Indian population (OR = 9.0, 95%CI 2.79–29.06, p = 0.0002). A significantly higher frequency of G allele was also observed in CAD patients than in controls (OR 2.64, 95%CI 1.61–4.33, p = 0.001).

Conclusions

The reduced serum PON1 level is associated with CAD. PON1 rs662 gene polymorphism is significantly associated with CAD susceptibility in the North Indian population.

PON-1 haplotype (-108C>T, L55M, and Q192R) modulates the serum levels and activity PONase promoting an atherogenic lipid profile in rheumatoid arthritis patients

INTRODUCTION/OBJECTIVE

Paraoxonase 1 (PON1) promotes antioxidant and antiatherogenic activity related to the hydrolysis of oxidized lipids of low-density lipoproteins. In rheumatoid arthritis (RA) patients, it has been reported that low PON1 activity is related to an impaired lipid profile, increasing cardiovascular risk (CVR). The goal of this study was to analyze the effect of common PON1 polymorphisms and haplotypes on enzymatic activity, PON1 serum levels (PON1s), and lipid parameters related to atherogenic profile in RA patients.

METHODS

A cross-sectional study was carried out on 250 Mexican patients with RA. The lipid profile was determined by colorimetric tests. The PON1 activity (CMPAase) was measured by spectrophotometry. The levels of PON1s were determined by ELISA, and the polymorphisms in the PON-1 gene (-108C>T, L55M, and Q192R) were genotyped by the PCR-RFLP method. The haplotypes were estimated and statistical analysis was performed.

RESULTS

The median of the CMPAase activity and PON1 levels was 13.91 U/mL and 24.75 ng/mL, respectively. The CMPAase activity was significantly lower in carriers of -108TT and 192QQ genotypes (β = - 4.09, P = 0.001 and β = - 3.73, P = 0.002, respectively); moreover, the PON1 levels were lower in 192Q allele carriers (P < 0.01). The TLQ haplotype was associated with CMPAase activity < 13.91 U/mL (OR = 2.29, P < 0.001), as well as with levels of PON1s < 24.75 ng/mL (OR = 1.65, P = 0.017). In this study, the CMPAase activity (< 13.91 U/mL) showed a positive association with lower levels of high-density lipoprotein cholesterol (HDL-c; < 40/50 mg/dL), and with a triglycerides/HDL-c ratio > 3%, and a total cholesterol/HDL-c ratio > 4.5/5%, all representatives of an atherogenic risk lipid profile.

CONCLUSIONS

PON1 polymorphisms modulate the CMPAase activity and PON1 levels in Mexican patients with RA. The CMPAase activity < 13.91 U/mL is associated with an atherogenic lipid profile, independently of inflammation markers and treatment with anti-rheumatic drugs. Key Points •The haplotype TLQ is a marker for low PONase activity in rheumatoid arthritis. •The haplotype TLQ is a marker for low PON1 serum levels in rheumatoid arthritis. •The enzymatic PON1 activity represents the best marker for an atherogenic lipid profile in rheumatoid arthritis, in comparison with PON1 levels. •The haplotype TLQ is a marker of low PON1 activity, levels of PON1s, and atherogenic lipid profile, independent of treatment therapy in rheumatoid arthritis.