Superoxide dismutase, catalase, glutathione peroxidase and gluthatione S-transferases M1 and T1 gene polymorphisms in three Brazilian population groups

GSTP1 rs1695 and rs1871042, and SOD2 rs4880 as molecular markers of lipid peroxidation in blood storage

BACKGROUND

Red blood cells (RBC) are subject to oxidative stress by reactive oxygen species (ROS) during storage. Molecular characterisation of oxidative stress in stored RBC, which may also occur in other blood components during long periods of storage, is rare.

MATERIALS AND METHODS

Our study included 45 healthy RBC donors recruited in Brazil. Blood was collected into standard Grifols® Triple Bags containing CPD SAG-M. Haematological values, biochemical data, and oxidative stress markers were assessed weekly during storage until 42 days after collection. GSTM1 and GSTT1 were determined by multiplex-polymerase chain reaction (PCR), while GSTP1 rs1695 and rs1871042, CAT rs1001179, and SOD2 rs4880 were evaluated by real-time PCR.

RESULTS

A direct proportional relationship was found between storage time and levels of ROS and thiobarbituric acid reactive substances (TBARS, indicators of lipid peroxidation) (p<0.001). These parameters were indirectly proportional to ABTS values (p<0.001). The plasma concentration of TBARS was associated with GSTP1 303AG/GG, GSTP1 -16CT/TT, and SOD2 47CT/TT genotypes. Single-nucleotide polymorphisms at the CAT C-262T gene were not associated with TBARS, nor were oxidative markers of ROS.

DISCUSSION

Prolonged storage may result in the onset of erythrocyte deterioration. Our results clearly indicate that erythrocytes are capable of attenuating ROS for 2 weeks of storage. We observed an association between elevated TBARS levels and the presence of GSTP1 and SOD2 variants in stored RBC. Although notable for heterozygous variants, this association was even stronger for the homozygous variants GSTP1 rs1695 (303GG), GSTP1 rs1871042 (-16TT), and SOD2 rs4880 (47TT). These findings accentuate the importance of genetic factors in storage lesions and will expand our understanding and consideration of endogenous and exogenous causes in improving clinical treatment with blood transfusions.

Glutathione S-transferase, catalase, and mitochondrial superoxide dismutase gene polymorphisms modulate redox potential in systemic lupus erythematosus patients from Manaus, Amazonas, Brazil

OBJECTIVE

To investigate the frequency of glutathione S-transferase (GST), catalase, and SOD2 genetic polymorphisms and their correlation with SLE.

METHODS

A total of 290 females (patients = 151; controls= 139) were recruited. Multiplex PCR was performed for genotyping GSTM1 and GSTT1 genes, whereas real-time qPCR was used for determination of SNPs: CAT C262T, SOD2 C47T, GSTP1 A313G and GSTP1 IVS6 -C16T.

RESULTS

Thiol levels are decreased in SLE patients (p<0.001), while MDA levels were significantly higher (p<0.001) and those carrying the polymorphisms had higher rates of oxidative stress. Patients with double null deletion GSTT1^null/GSTM1^null had a frequency almost five times higher than the controls (p<0.001, OR 4.81, CI 1.98-12.11). SLE patients had a lower wild-type frequency of SOD2^CC allele compared to controls (12.4% vs 27.3%). Statistical significances were observed on the association between the GSTT1^null and GSTM1^null with SOD2^mut (p<0.001, OR 0.15, CI 0.05-0.47), with GSTP1 A303G (p=0.012, OR 0.19, CI 0.05-0.69), and with GSTP1 IVS6 (p=0.008, OR 0.14, CI 0.03-0.63). The same was observed between SOD2 C47T with GSTP1 A303G (p=0.09, OR 0.27, CI 0.09-0.74) and GSTP1 IVS6 (p=0.036, OR 0.41, CI 0.18-0.92).

CONCLUSIONS

The deletion GSTT1^null/GSTM1^null may contribute to the increased of the oxidative stress in SLE patients. Isolated GSTP1 and CAT polymorphisms do not seem to influence the increased oxidative stress, neither SLE clinical manifestations. SOD2 47^CT/TT allele may have greater oxidative stress due to structural change in the protein and decreased H₂O₂ production. The combination of polymorphic genes may be involved in the pathogenesis of the disease. Key points • Major question of our paper: Many studies have shown that the antioxidant status levels are decreased in patients with SLE, especially in severe stages of disease. We believe that this paper will be of interest to the readership of your journal had the involvement of polymorphisms and mutations in several genes that contribute to the genetic etiology of SLE, suggesting that these may influence the mechanisms of disease. • Our results. Thiol level was significantly (p<.001) lower and MDA level significantly increased (p<.001) among SLE patients. Those carrying the polymorphisms had higher rates of oxidative stress. SLE Patients had a frequency almost five times higher of double null deletion GSTT1null/GSTM1null than the controls. SLE Patients had a lower wild type frequency of SOD2CC allele compared to controls (12.4% vs 27.3%). We believed the deletion GSTT1null/GSTM1null may contribute to the increased of the oxidative stress in SLE patients while carriers of the mutant SOD2 47CT/TT allele may have greater oxidative stress due to structural change in the protein and decreased H2O2 production. The combination of polymorphic genes may be involved in the pathogenesis of the disease. • Implications of our results: Evidence for the involvement of genetic factors in severe clinical to lupus is compelling. This manuscript shows genetic insights in pathogenic pathways that may lead to severe clinical implications to LES. Therefore, it is necessary to understand their impact on overall disease pathogenesis and prognosis in these patients. We understand from general consensus about environmental factors can modify disease, however, maybe just in individuals who have a permissive genetic background. Even that no single gene predisposes some individuals to LES, we believe the genetic factors described in this manuscript are important elements in susceptibility to severe clinical to LES.

Combined GSTM1 and GSTT1 null genotypes are strong risk factors for atherogenesis in a Serbian population

Oxidative stress (OS) plays an important role in atherogenesis and since glutathione S-transferases (GSTs) provide protection against OS, we have tested the hypothesis that deletion polymorphisms in two GSTs (GSTM1 and GSTT1) may affect the risk of developing atherosclerosis. A total of 382 individuals (200 patients with atherosclerosis and 182 healthy controls) were included in this association study. Genomic DNA was isolated from peripheral blood cells or from buccal epithelial cells and genotyping was performed using multiplex-PCR or real-time PCR methods. GSTM1 null genotype was significantly more frequent in atherosclerotic patients than in controls (52.0% vs 34.1%) and individuals with the GSTM1 null genotype had an approximately 2-fold increase in atherosclerosis risk (OR: 2.1, 95%CI=1.39-3.17, P=0.0004). GSTT1 null genotype alone did not show a statistically significant effect on atherosclerosis risk modulation, but the association approached significance (OR: 1.57, 95%CI=0.94-2.64, P=0.08). The combined analysis showed that the presence of both genes had a protective effect against atherosclerosis (OR=0.55, 95%CI=0.37-0.83, P=0.005) while double null genotypes led to a robust atherosclerosis risk increase (OR: 8.14, 95%CI= 2.41-27.51, P < 0.0001). This study demonstrated that the GSTM1 null and combined GSTM1/GSTT1 null genotypes are susceptibility factors for development of atherosclerosis in a Serbian population.

Association between interleukin 6 -174 G/C promoter gene polymorphism and runners' responses to the dietary ingestion of antioxidant supplementation based on pequi (Caryocar brasiliense Camb.) oil: a before-after study

Exercise is a double-edged sword: when practiced in moderation, it increases the expression of antioxidant enzymes, but when practiced strenuously it causes oxidative stress and cell damage. In this context, polymorphisms in the interleukin (IL)-6 gene should be investigated better because they can influence performance, at least in exercise that generates oxidative stress and leads to muscular injuries with consequent inflammation. In this work, we investigated the influence of IL-6 -174 G/C polymorphism on tissue damage and inflammation markers, lipid peroxidation, hemogram and lipid profile of runners before and after ingestion of 400 mg of pequi oil in capsules supplied daily for 14 consecutive days. The IL-6 genotypes were associated with significant differences in lipid peroxidation, with the CC mutant having lower values. There were also significant differences among these genotypes in the response to supplementation with pequi oil, exercise-induced damage and C-reactive protein (CRP) levels. The best protection against damage was observed with the heterozygous genotype. Although the CC genotype showed an increase in CRP levels after supplementation, the lack of a positive correlation between triglycerides and high-sensitivity CRP in this mutant genotype after supplementation indicated a protective effect of pequi. These findings deserve further investigation, particularly with regard to the quantification of circulating IL-6 concentrations.

Influence of Gender and SNPs in GPX1 Gene on Biomarkers of Selenium Status in Healthy Brazilians

Selenium (Se) status varies worldwide as a result of natural variation of Se content in soils, dietary pattern, and the presence of SNPs. Further, Se status in Brazilians and its relationship between genetic variation and Se biomarkers is unknown. This work investigated the association between SNPs in glutathione peroxidase genes and biomarkers of Se status in healthy Brazilians. The study was conducted in 116 healthy adults in São Paulo, Brazil. Plasma and erythrocyte Se were measured by HGFAAS. Erythrocyte GPx (eGPx) activity was measured spectrometrically in a biochemical analyzer. Genotypes were determined by real-time PCR using Taqman(®) Assays. eGPx activity was higher in females compared with males. Lower erythrocyte Se concentrations were found in heterozygous GC carriers for GPX1 rs8179169. eGPx activity was higher in females with the common genotypes, except for rs8179169. GC carriers for rs8179169 had lower erythrocyte Se in both genders, and only male carriers of the variant alleles of both rs1050450 and rs1800668 had higher eGPx activity. In conclusion, the genotype for SNPs in GPX1 and gender affected biomarkers of Se status in this pilot study with healthy Brazilians.

MnSOD and GPx1 polymorphism relationship with coronary heart disease risk and severity

BACKGROUND

Disturbance of the equilibrium between reactive oxygen species (ROS) and anti-oxidants (AOX) has been implicated in various diseases, including atherosclerosis, the most common pathologic process underlying coronary heart disease (CHD). Thus, the defense systems against ROS are critical protecting blood vessel walls against oxidative damage. In this study, we investigate whether Ala16Val MnSOD and Pro198Leu GPx polymorphisms are associated with CHD susceptibility and/or severity.

METHODS

Both polymorphisms were genotyped in a sample of 203 controls and 164 patients. CHD risk and severity, antioxidant status (enzymatic and/or non enzymatic) and biochemical parameters were assessed and analysed by genotype.

RESULTS

A significant association of MnSOD variant to CHD risk was revealed in males. Males harboring the Val/Val genotype were approximately at twofold increased risk of CHD compared to controls (Ala carriers vs Val/Val, adjusted OR 1.89; 95 % CI 1.18‒3.42, p = 0.03). Significant decreases in SOD activity and total antioxidant status (TAS) were observed in Val carriers and by CHD status. Whereas, no association of GPx variant genotype (Leu/Leu) and activity to cardiopathy events was discerned. CHD severity, as demonstrated by the number of vessel stenosis, was associated with significantly higher frequency of Val allele and LDL levels in CHD subjects.

CONCLUSIONS

Our results showed a lack of association of Pro198Leu GPx polymorphism to CHD risk and severity. However, they suggest that Ala16Val MnSOD polymorphism and decreased antioxidant defences are likely contributed to CHD risk in Tunisian men. Furthermore, the Val encoding MnSOD allele and decreased SOD activity were significantly correlated with CHD stenosis progression.

Biomarkers of mercury exposure in the Amazon

Mercury exposure in the Amazon has been studied since the 1980s decade and the assessment of human mercury exposure in the Amazon is difficult given that the natural occurrence of this metal is high and the concentration of mercury in biological samples of this population exceeds the standardized value of normality established by WHO. Few studies have focused on the discovery of mercury biomarkers in the region's population. In this way, some studies have used genetics as well as immunological and cytogenetic tools in order to find a molecular biomarker for assessing the toxicological effect of mercury in the Amazonian population. Most of those studies focused attention on the relation between mercury exposure and autoimmunity and, because of that, they will be discussed in more detail. Here we introduce the general aspects involved with each biomarker that was studied in the region in order to contextualize the reader and add information about the Amazonian life style and health that may be considered for future studies. We hope that, in the future, the toxicological studies in this field use high technological tools, such as the next generation sequencing and proteomics skills, in order to comprehend basic questions regarding the metabolic route of mercury in populations that are under constant exposure, such as in the Amazon.

Reference gene selection for qPCR in Ammopiptanthus mongolicus under abiotic stresses and expression analysis of seven ROS-scavenging enzyme genes

Ammopiptanthus mongolicus, the only evergreen broadleaf shrub endemic to the northwest desert of China, is a valuable species for plant abiotic stress research. No report has so far described the selection of reference genes to get stringent normalization for qPCR in A. mongolicus. This work identified reliable reference genes for normalization of qPCR data in A. mongolicus under abiotic stresses from 14 reference gene candidates (UBQ, Tub1, Tub2, Abc1, Ubc1, Ubc2, Ubc4, Ubc5, eIF1, eIF2, eIF3, eIF4, EF1, EF2), and used the most suitable combination of reference genes to normalize the expression profiles of seven ROS-scavenging enzyme genes (AmSOD, AmAPX, AmGPX, AmCAT, AmGLR, AmPrx, and AmTrx). We set a series of 22 experimental samples covering the control and different time points under cold, dry, salt, and heat stresses. According to geNorm and NormFinder, the combination of eIF1 and eIF3 was best for accurate normalization across all the treatments, confirmed by normalizing qPCR data with AmHsp90. In contrast, these data show that Tub1, Abc1, and EF1 are not suitable reference gene candidates. After being normalized against eIF1 and eIF3, the seven ROS-scavenging enzyme genes exhibited differentially up- or down-regulated expression patterns. AmSOD and AmGPX were up-regulated by all four treatments, indicating that they may participate in an anti-oxidative mechanism under abiotic stresses in A. mongolicus. AmCAT exhibited a much higher expression level than AmAPX, AmPrx, and AmGPX, suggesting a principle role in detoxifying excessive H₂O₂. AmSOD, AmGPX and AmAPX showing the most abundant transcripts under heat, AmCAT and AmGLR under drought, and AmPrx under salt, were observed. Expression patterns of the seven ROS-scavenging enzyme genes suggest different antioxidant protection roles of these genes under abiotic stresses. These results are valuable for future research on gene expression and abiotic stress tolerance in A. mongolicus.

Genetic polymorphisms influence runners' responses to the dietary ingestion of antioxidant supplementation based on pequi oil (Caryocar brasiliense Camb.): a before-after study

Genes have been implicated in the levels of oxidative stress, lipids, CVD risk, immune reactivity, and performance. Pequi oil (Caryocar brasiliense) has shown anti-inflammatory and hypotensive effects, besides reducing exercise-induced DNA, tissue damages, and anisocytosis. Given that diet can interact with the human genome to influence health and disease, and because genetic variability can influence response to diet, we aim to investigate the influence of 12 gene polymorphisms on inflammatory markers, postprandial lipids, arterial pressure, and plasma lipid peroxidation of runners (N = 125), before and after 14 days of 400 mg pequi-oil supplementation, after races under closely comparable conditions. Arterial pressure was checked before races; blood samples were taken immediately after racing to perform leukogram and plateletgram, Tbars assay, lipid, and CRP dosages and genotyping. CAT, GST-M1/T1, CRP-G1059C, and MTHFR-C677T polymorphisms influenced post-pequi-oil responses in leukogram; Hp and MTHFR-C677T, in plateletgram; Hp, ACE, GSTT1, and MTHFR-A1298C, in lipid profile; MTHFR-A1298C, in C-reactive protein (CRP) levels; and Hp and MnSOD, in Tbars assay. Differences between ACE genotypes in leukogram and total cholesterol disappeared after pequi, and the same occurred for Hp and MnSOD in Tbars assay and for MTHFR-A1298C with CRP levels. Because genetic inheritance is one of the factors that drive atherosclerosis-related lipid abnormalities, results can contribute to a greater understanding of the influence of genetic polymorphisms in situations that push up free radicals. Knowledge is also expanded on how antioxidant supplementation affects an individual's genes and how athletic genetic makeup can affect the way a person responds to antioxidant supplements.