Association between rs4673 (C/T) and rs13306294 (A/G) haplotypes of NAD(P)H oxidase p22phox gene and severity of stenosis in coronary arteries

Effect of C242T Polymorphism in the Gene Encoding the NAD(P)H Oxidase p22phox Subunit and Aerobic Fitness Levels on Redox State Biomarkers and DNA Damage Responses to Exhaustive Exercise: A Randomized Trial

NAD(P)H oxidases (NOXs) constitute a principal source of cellular reactive oxygen species (ROS) and contribute to exercise-induced ROS production in the skeletal muscle. Here, we aimed to investigate the effect of single-bout exhaustive exercise on redox state biomarkers and oxidative DNA damage based on the C242T polymorphism in the gene encoding NOXs subunit p22^phox (CYBA) and aerobic fitness levels. We enrolled 220 healthy adults in their 20s (men, n = 110; women, n = 110), who were divided into CC genotype and T allele groups through the analysis of the CYBA C242T polymorphism. Furthermore, maximum oxygen uptake (VO₂max) was evaluated to divide subjects into high fitness (HF; 70th percentile for aerobic fitness) and mid-range fitness (MF; 40-60th percentile for aerobic fitness) groups, with a total of 32 subjects assigned to four groups (eight subjects per group): CC genotype and HF group (CC + HF), CC genotype and MF group (CC + MF), T allele and HF group (T + HF), and T allele and MF group (T + MF). All subjects performed treadmill running exercise at 85% of VO₂max until exhaustion. Plasma lactate, malondialdehyde (MDA), superoxide dismutase (SOD), and lymphocyte DNA damage (tail DNA percentage [TD], tail length [TL], and the tail moment [TM]) were measured in the blood samples obtained immediately before (IBE), immediately after (IAE), and 30 min after exercise (30 MAE). Plasma lactate levels, SOD activities, and lymphocyte DNA damage markers (TD, TL, and TM) were significantly increased at IAE than that at IBE and significantly decreased at 30 MAE (p < 0.05). All groups displayed increased plasma MDA levels at IAE rather than at IBE, with CC + MF being significantly higher than T + HF (p < 0.05); only the CC + HF and T + HF groups exhibited a significant reduction at 30 MAE (p < 0.05). Moreover, TL at IAE was significantly higher in the CC + MF group than in the T + HF group (p < 0.05), and significantly higher in the CC + MF and CC + HF groups than in the T + HF group at 30 MAE (p < 0.05). TM was significantly higher in the T + MF than in the T + HF group at IAE (p < 0.05) and that of CC + MF was significantly higher than CC + HF and T + HF values at IAE and 30 MAE (p < 0.05). These results suggest that single-bout exhaustive exercise could induce peripheral fatigue and the accumulation of temporary redox imbalance and oxidative DNA damage. Moreover, high aerobic fitness levels combined with the T allele may protect against exercise-induced redox imbalance and DNA damage.

The effects of oxidative stress on the development of atherosclerosis

Atherosclerosis is a cardiovascular disease (CVD) known widely world wide. Several hypothesizes are suggested to be involved in the narrowing of arteries during process of atherogenesis. The oxidative modification hypothesis is related to oxidative and anti-oxidative imbalance and is the most investigated. The aim of this study was to review the role of oxidative stress in atherosclerosis. Furthermore, it describes the roles of oxidative/anti-oxidative enzymes and compounds in the macromolecular and lipoprotein modifications and in triggering inflammatory events. The reactive oxygen (ROS) and reactive nitrogen species (RNS) are the most important endogenous sources produced by non-enzymatic and enzymatic [myeloperoxidase (MPO), nicotinamide adenine dinucleotide phosphate (NADH) oxidase and lipoxygenase (LO)] reactions that may be balanced with anti-oxidative compounds [glutathione (GSH), polyphenols and vitamins] and enzymes [glutathione peroxidase (Gpx), peroxiredoxins (Prdx), superoxide dismutase (SOD) and paraoxonase (PON)]. However, the oxidative and anti-oxidative imbalance causes the involvement of cellular proliferation and migration signaling pathways and macrophage polarization leads to the formation of atherogenic plaques. On the other hand, the immune occurrences and the changes in extra cellular matrix remodeling can develop atherosclerosis process.

The active participation of p22phox-214T/C in the formation of intracranial aneurysm and the suppressive potential of edaravone

Oxidative stress reactions play an important role in the pathogenesis of intracranial aneurysm (IA). p22phox is involved in the oxidative stress reaction, and it is a critical subunit of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. The present study investigated the association of genetic variants within the gene encoding p22phox‑214T/C with IA. The p22phox‑214T/C gene polymorphisms in 192 cases of IA and 112 controls were analyzed by polymerase chain reaction‑restriction fragment length polymorphism (PCR‑RFLP). The mRNA expression of NADPH oxidase was also analyzed by RT‑PCR. The results of RT‑PCR were validated by ELISA. In a rabbit model of elastase‑induced aneurysm, we used edaravone for anti‑oxidative stress treatment to observe the curative effects. In the clinical cases, a significant difference in p22phox‑214T/C allele frequencies in the IA group was observed compared with the control group (P<0.001). The expression level of NADPH oxidase was differed significantly between the IA group and the control group. In the rabbit model of elastase‑induced aneurysm, the success rate of the aneurysmal model in the edaravone group and the wound ulcer rate were lower than those in the control group. In addition, the diameter of the aneurysm was smaller than in the edaravone group than in the control group (3.26±0.13 mm vs. 3.85±0.07 mm), and the expression of matrix metalloproteinase‑9 (MMP‑9) was significantly lower than that in the control group (P<0.0001). Thus, these data suggest the active participation of p22phox‑214T/C in the formation of IA and the suppressive potential of edaravone against IA formation.

p22phox C242T gene polymorphism and overt diabetic nephropathy: a meta-analysis of 1,452 participants

BACKGROUND/AIMS

The p22phox C242T gene polymorphism (rs4673) may be linked to an increased susceptibility for overt diabetic nephropathy (ODN), but the study results are still inconclusive.

METHODS

To explore the relationship between p22phox C242T gene polymorphism and ODN, the current meta-analysis of 707 ODN patients and 745 controls from five individual studies was conducted. The pooled odds ratio (OR) and its corresponding 95% confidence interval (CI) were evaluated by either a random or fixed effect model.

RESULTS

In our meta-analysis, a significant relationship between the p22phox C242T gene polymorphism and ODN was found under allelic (OR, 2.760; 95% CI, 1.400 to 5.450; p = 0.004), recessive (OR, 5.080; 95% CI, 1.020 to 25.430; p = 0.05), dominant (OR, 1.700; 95% CI, 1.167 to 2.477; p = 0.006), homozygous (OR, 3.900; 95% CI, 1.022 to 14.889; p = 0.046), heterozygous (OR, 1.523; 95% CI, 1.167 to 1.986; p = 0.002), and additive genetic models (OR, 2.019; 95% CI, 1.232 to 3.309; p = 0.005).

CONCLUSIONS

A positive correlation between p22phox C242T gene polymorphism and ODN risk was found. The T allele carriers of p22phox C242T gene polymorphism might be predisposed to ODN.

Association analysis of rs1049255 and rs4673 transitions in p22phox gene with coronary artery disease: A case-control study and a computational analysis

BACKGROUND

The p22phox gene encodes the main subunit of NADH/NADPH-oxidase. This enzyme is expressed in smooth muscle cells of arteries, and it produces the reactive oxygen species. On the other hand, oxidative stress plays a main role in the pathogenesis of coronary artery disease (CAD).

AIM

The aim of this study is to evaluate the association between rs4673 and rs1049255 polymorphisms of p22phox gene with CAD in an Iranian population which was followed with a computational analysis approach.

METHODS

In a cross-sectional study, we collected blood samples of 302 Iranian Caucasian including 143 patients and 159 healthy controls. Genotype of the polymorphisms was detected through PCR-RFLP method. A computational analysis was also performed using SNAP, Polyphen-2, Chou-Fasman, RNAsnp, and miRNA SNP databases.

RESULTS

Data of case control study demonstrated that CT genotype (R = 1.84, 95% CI = 1.13-3.00, p = 0.014) and T allele (OR = 1.53, 95% CI = 1.09-2.15, p = 0.013) of rs4673 polymorphism, have a significant association with enhanced risk of CAD. But rs1049255 analysis demonstrated the absence of such an association with CAD. Indeed, in silico data analysis demonstrated that rs4673 transition could impact on function of p22phox protein (SNAP score 56, expected accuracy 75%; Polyphen-2 score 0.99, sensitivity 0.09, specificity 0.99). Data derived from miRNA SNP database demonstrated that rs1049255 polymorphism increases the affinity of attachment between has-miR-3689a-3b with 3'-UTR of p22phox gene.

CONCLUSION

Our data demonstrated that rs4673 transition may be involved in susceptibility to CAD and could be applied as a potential biomarker for this disease.

p22phox C242T Single-Nucleotide Polymorphism Inhibits Inflammatory Oxidative Damage to Endothelial Cells and Vessels

BACKGROUND

The NADPH oxidase, by generating reactive oxygen species, is involved in the pathophysiology of many cardiovascular diseases and represents a therapeutic target for the development of novel drugs. A single-nucleotide polymorphism, C242T of the p22(phox) subunit of NADPH oxidase, has been reported to be negatively associated with coronary heart disease and may predict disease prevalence. However, the underlying mechanisms remain unknown.

METHODS AND RESULTS

With the use of computer molecular modeling, we discovered that C242T single-nucleotide polymorphism causes significant structural changes in the extracellular loop of p22(phox) and reduces its interaction stability with Nox2 subunit. Gene transfection of human pulmonary microvascular endothelial cells showed that C242T p22(phox) significantly reduced Nox2 expression but had no significant effect on basal endothelial O2 (.-) production or the expression of Nox1 and Nox4. When cells were stimulated with tumor necrosis factor-α (or high glucose), C242T p22(phox) significantly inhibited tumor necrosis factor-α-induced Nox2 maturation, O2 (.-) production, mitogen-activated protein kinases and nuclear factor κB activation, and inflammation (all P<0.05). These C242T effects were further confirmed using p22(phox) short-hairpin RNA-engineered HeLa cells and Nox2(-/-) coronary microvascular endothelial cells. Clinical significance was investigated by using saphenous vein segments from non-coronary heart disease subjects after phlebotomies. TT (C242T) allele was common (prevalence of ≈22%) and, in comparison with CC, veins bearing TT allele had significantly lower levels of Nox2 expression and O2 (.-) generation in response to high-glucose challenge.

CONCLUSIONS

C242T single-nucleotide polymorphism causes p22(phox) structural changes that inhibit endothelial Nox2 activation and oxidative response to tumor necrosis factor-α or high-glucose stimulation. C242T single-nucleotide polymorphism may represent a natural protective mechanism against inflammatory cardiovascular diseases.

Genetic Variants of Cytochrome b-245, Alpha Polypeptide Gene and Premature Acute Myocardial Infarction Risk in an Iranian Population

Background

Oxidative stress induced by superoxide anion plays critical roles in the pathogenesis of coronary artery disease (CAD) and hence acute myocardial infarction (AMI). The major source of superoxide production in vascular smooth muscle and endothelial cells is the NADPH oxidase complex. An essential component of this complex is p22phox, that is encoded by the cytochrome b-245, alpha polypeptide (CYBA) gene. The aim of this study was to investigate the association of CYBA variants (rs1049255 and rs4673) and premature acute myocardial infarction risk in an Iranian population.

Methods

The study population consisted of 158 patients under the age of 50 years, with a diagnosis of premature AMI, and 168 age-matched controls with normal coronary angiograms. Genotyping of the polymorphisms was performed by the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).

Results

There was no association between the genotypes and allele frequencies of rs4673 polymorphism and premature acute myocardial infarction (P>0.05). A significant statistical association was observed between the genotypes distribution of rs1049255 polymorphism and AMI risk (P=0.037). Furthermore, the distribution of AA+AG/GG genotypes was found to be statistically significant between the two groups (P=0.011).

Conclusions

Our findings indicated that rs1049255 but not rs4673 polymorphism is associated with premature AMI.

The role of CYBA (p22phox) and catalase genetic polymorphisms and their possible epistatic interaction in cervical cancer

Human papillomavirus (HPV) infection is necessary but not a sufficient cause for the development of invasive cervical cancer (ICC). Epithelial tissues, target for HPV, are exposed to reactive oxygen species (ROS) associated with tumor initiation and progression. The NADPH oxidase (NOX) and catalase (CAT) are involved in hydrogen peroxide (H2O2) production and inactivation, respectively. P22phox is the NOX subunit encoded by the CYBA gene that has a functional polymorphism (C-242T). This protein is involved in the regulation of electron transfer to oxygen. CAT is a hemic enzyme that plays a role in regulating H2O2 concentration, with a functional polymorphism (C-262T) in its gene. We evaluated CYBA C-242T and CAT C262T genetic polymorphisms and their interaction in 132 women with ICC. We found that CYBA C-242T and CAT C262T genotype frequencies were significantly different between ICC and controls (χ (2) test, p = 0.017 and p = 0.009, respectively). Women with the C/T CYBA-242 genotype had a lower risk for ICC development (odds ratio (OR) = 0.515, 95% confidence interval (CI) 0.291-0.914, p = 0.023) whereas T/T CAT-262 genotype carriers present an increased risk for ICC (OR = 3.034, 95% CI 1.462-6.298, p = 0.003). Women with C/C genotype for CYBA and T/T genotype for CAT had an increased risk to develop ICC comparing with the interaction of the other possible genotypes of both genes (OR = 3.952, 95% CI 1.075-14.521, p = 0.032). The CYBA C-242T and CAT C-262T genetic polymorphisms and their epistatic interactions can be associated with ICC through mechanisms related with the role of ROS in cell proliferation and apoptosis.

Polymorphisms of C242T and A640G in CYBA gene and the risk of coronary artery disease: a meta-analysis

Background

Coronary artery disease (CAD) is a leading cause of mortality in many countries. Considerable studies have been carried out to investigate the relationship between the C242T and A640G polymorphisms of CYBA gene and CAD, but the results were still inconsistent. Hence we conducted a meta-analysis to clarify the association.

Methods and Results

A total of 21 eligible literatures were included in the meta-analysis. We observed a significant decreased risk of CAD for C242T polymorphism in Asian population under an allelic model (OR 0.75; 95% CI 0.67–0.84) and a dominant model (OR 0.69; 95% CI 0.61–0.79), however, in overall population and other population no significant association was revealed. We also found A640G polymorphism may contribute to reducing CAD risk under an allelic model (OR 0.84; 95% CI 0.75–0.93), dominant model (OR0.77; 95% CI 0.64–0.92) and recessive model (OR0.82; 95% CI 0.69–0.97). No publication bias was found.

Conclusion

Our meta-analysis confirmed a protective effect of C242Tpolymorphism on CAD in Asian population and indicated that A640G polymorphism was significantly associated with decreased risk of CAD.

Relationship of the p22phox (CYBA) gene polymorphism C242T with risk of coronary artery disease: a meta-analysis

Background

Observational and experimental studies have thus far been unable to resolve whether the CYBA C242T polymorphism is associated with coronary artery disease (CAD). Therefore, we undertook a comprehensive meta-analysis to more precisely evaluate the influence of this polymorphism on CAD and potential biases.

Methods

We screened MEDLINE, Embase, CNKI, Wanfang and CBM up to January 2013 and extracted data from 22 studies with 9,279 CAD patients and 9,349 controls. A random-effects model was exploited to synthesize the inconsistent outcomes of the individual studies, while addressing between-study heterogeneity and publication bias.

Results

The CYBA C242T polymorphism conformed to Hard-Weinberg Equilibrium for all studies (P>0.05). Overall comparison of the T allele with the C allele produced a non-significant risk estimate for CAD but with striking heterogeneity (T versus C: P = 0.87, OR = 0.99, 95%CI 0.89–1.11, P_{heterogeneity}<0.0001, I² = 67.8%). However, subgroup analysis by ethnicity documented that the T allele carriers had a marginal risk increase (21%) of CAD among Caucasians (recessive genetic model: P = 0.05, 95%CI 1.00–1.46, P_{heterogeneity} = 0.15, I² = 29.1%). Then data were divided into study design, the significance of CAD risk increase was substantially strengthened in matched case-control studies (allele comparison: P = 0.02, OR = 1.13, 95%CI 1.02–1.26, P_{heterogeneity} = 0.24, I² = 21.6%).Further meta-regression analysis identified that a large proportion of heterogeneity was explained by body mass index (BMI) (P = 0.03, OR = 1.07, 95%CI 1.01–1.15) and study design (P = 0.03, OR = 1.30, 95%CI 1.02–1.64).There was no obvious publication bias as verified by funnel plot and Egger's linear regression test (t = −0.25, P = 0.81 for allele comparison).

Conclusion

Taken together, our results suggested the CYBA C242T polymorphism might be a risk-conferring factor on developing CAD and BMI and study design were probable sources of between-study heterogeneity.

Association of the C242T polymorphism in the NADPH oxidase p22 phox gene with carotid atherosclerosis in Slovenian patients with type 2 diabetes

Oxidative stress plays an important role in the pathogenesis of diabetes and its complications. Genetic variations of enzymes producing reactive oxygen species could change their activity, thus contributing to the susceptibility to oxidative stress. The aim of this study was to examine the role of the NADPH oxidase C242T polymorphism in the development of carotid atherosclerosis in patients with type 2 diabetes. 286 diabetic patients and 150 healthy controls were enrolled in the study. Carotid atherosclerosis was quantified ultrasonographically as carotid intima-media thickness, plaque score (0-6) and plaque type (1-5). Diabetic patients were divided into low and high risk groups based on ultrasound phenotypes of carotid atherosclerosis. Genotypes were determined by real-time PCR. Levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) were measured by enzyme-linked immunosorbent assay (ELISA). Diabetic patients demonstrated a statistically significant difference compared to healthy controls in the following parameters: age, BMI, waist circumference, smoking prevalence, glucose, triglyceride and 8-OHdG serum levels. Control subjects had significantly higher levels of HDL, LDL and total cholesterol than diabetics (p < 0.001). The NADPH C242T polymorphism was not related with clinical characteristics, lipid parameters and 8-OHdG serum levels. We found no significant difference in the NADPH genotype distribution between diabetics and controls (p = 0.19) nor between low and high risk subgroups of diabetics (mean CIMT: p = 0.67; plaque score: p = 0.49, plaque type: p = 0.56). In the present study the NADPH C242T polymorphism was not associated with the degree of oxidative stress and carotid atherosclerosis. Further studies will show if it can be used as a genetic marker for carotid atherosclerosis in diabetic patients.