Glutathione S-Transferase T1 (GSTT1) Null Polymorphism, Smoking, and Their Interaction in Coronary Heart Disease: A Comprehensive Meta-Analysis

Genetic Polymorphisms and Genetic Risk Scores Contribute to the Risk of Coronary Artery Disease (CAD) in a North Indian Population

Coronary artery disease (CAD) is the leading cause of death in India. Many genetic polymorphisms play a role in regulating oxidative stress, blood pressure and lipid metabolism, contributing to the pathophysiology of CAD. This study examined the association between ten polymorphisms and CAD in the Jat Sikh population from Northern India, also considering polygenic risk scores. This study included 177 CAD cases and 175 healthy controls. The genetic information of GSTM1 (rs366631), GSTT1 (rs17856199), ACE (rs4646994), AGT M235T (rs699), AGT T174M (rs4762), AGTR1 A1166C (rs5186), APOA5 (rs3135506), APOC3 (rs5128), APOE (rs7412) and APOE (rs429358) and clinical information was collated. Statistical analyses were performed using SPSS version 27.0 and SNPstats. Significant independent associations were found for GST*M1, GST*T1, ACE, AGT M235T, AGT T174M, AGTR1 A1166C and APOA5 polymorphisms and CAD risk (all p < 0.05). The AGT CT haplotype was significantly associated with a higher CAD risk, even after controlling for covariates (adjusted OR = 3.93, 95% CI [2.39-6.48], p < 0.0001). The APOA5/C3 CC haplotype was also significantly associated with CAD (adjusted OR = 1.86, 95% CI [1.14-3.03], p < 0.05). A higher polygenic risk score was associated with increased CAD risk (adjusted OR = 1.98, 95% CI [1.68-2.34], p < 0.001). Seven polymorphisms were independently associated with an increase in the risk of CAD in this North Indian population. A considerable risk association of AGT, APOA5/C3 haplotypes and higher genetic risk scores is documented, which may have implications for clinical and public health applications.

The importance of polymorphisms in the genes encoding glutathione S-transferase isoenzymes in development of selected cancers and cardiovascular diseases

Glutathione S-transferases are a family of enzymes, whose main role is to detoxify cells from many exogenous factors, such as xenobiotics or carcinogens. It has also been proven that changes in the genes encoding these enzymes may affect the incidence of selected cancers and cardiovascular diseases. The aim of this study was to review the most important reports related to the role of glutathione S-transferases in the pathophysiology of two of the most common diseases in modern society - cancers and cardiovascular diseases. It was shown that polymorphisms in the genes encoding glutathione S-transferases are associated with the development of these diseases. However, depending on the ethnic group, the researchers obtained divergent results related to this field. In the case of the GSTP1 A/G gene polymorphism was shown an increased incidence of breast cancer in Asian women, while this relationship in European and African women was not found. Similarly. In the case of cardiovascular diseases, the differences in the influence of GSTM1, GSTT1, GSTP1 and GSTA1 polymorphisms on their development or lack of it depending on the continent were shown. These examples show that the development of the above-mentioned diseases is not only influenced by genetic changes, but their pathophysiology is more complex. The mere presence of a specific genotype within a studied polymorphism may not predispose to cancer, but in combination with environmental factors, which often depend on the place of residence, it may elevate the chance of developing the selected disease.

The Role of Glutathione-S Transferase in Psoriasis and Associated Comorbidities and the Effect of Dimethyl Fumarate in This Pathway

Psoriasis vulgaris is a chronic inflammatory skin disease characterized by well-demarcated scaly plaques. Oxidative stress plays a crucial role in the psoriasis pathogenesis and is associated with the disease severity. Dimethyl fumarate modulates the activity of the pro-inflammatory transcription factors. This is responsible for the downregulation of inflammatory cytokines and an overall shift from a pro-inflammatory to an anti-inflammatory/regulatory response. Both steps are necessary for the amelioration of psoriatic inflammation, although additional mechanisms have been proposed. Several studies reported a long-term effectiveness and safety of dimethyl fumarate monotherapy in patients with moderate-to-severe psoriasis. Furthermore, psoriasis is a chronic disease often associated to metabolic comorbidities, as obesity, diabetes, and cardiovascular diseases, in which glutathione-S transferase deregulation is present. Glutathione-S transferase is involved in the antioxidant system. An increase of its activity in psoriatic epidermis in comparison with the uninvolved and normal epidermal biopsies has been reported. Dimethyl fumarate depletes glutathione-S transferase by formation of covalently linked conjugates. This review investigates the anti-inflammatory role of dimethyl fumarate in oxidative stress and its effect by reducing oxidative stress. The glutathione-S transferase regulation is helpful in treating psoriasis, with an anti-inflammatory effect on the keratinocytes hyperproliferation, and in modulation of metabolic comorbidities.

Association of GSTP1 Ile105Val polymorphism with the risk of coronary heart disease: An updated meta-analysis

Background

Numerous case-control studies have investigated the association between GSTP1 Ile105Val polymorphism and CHD risk, but the results from published studies were inconclusive. The present meta-analysis was performed to derive a more precise estimation.

Methods

PubMed, EMBASE, and Web of Science database searches were conducted to retrieve relevant articles.

Results

Ultimately, 5,451 CHD cases and 5,561 controls from 15 studies were included. Pooled analysis did not yield any statistically significant association between GSTP1 Ile105Val polymorphism and CHD risk for the overall population (Val vs. Ile: OR, 1.05; 95% CI, 0.93 to 1.18; Val/Val vs. Ile/Ile: OR, 1.09; 95% CI, 0.83 to 1.42; Val/Ile vs. Ile/Ile: OR, 1.09; 95% CI, 0.93 to 1.28; Val/Val vs. Val/Ile+Ile/Ile: OR, 1.04; 95% CI, 0.83 to 1.30; Val/Val+Val/Ile vs. Ile/Ile: OR, 1.14; 95% CI, 0.97 to 1.33). Subgroup analyses and sensitivity analyses indicated that GSTP1 Ile105Val polymorphism was still not associated with an increased risk of CHD. After excluding studies detected by Galbraith plots as major sources of heterogeneity, these relationships were still not significant.

Conclusions

The overall results did not reveal a major role of the GSTP1 Ile105Val polymorphism in modulating CHD risk. Well-designed studies with large sample sizes are needed to validate our findings and explore the possible gene-gene or gene-environment interactions.

Interaction between eNOS gene polymorphism and current smoking on susceptibility to coronary heart disease in Chinese people

OBJECTIVE

This study aims to explore the relation between endothelial nitric oxide synthase (eNOS) single-nucleotide polymorphisms (SNPs) and the risk of coronary heart disease (CHD).

METHODS

SNPstats (online software: http://bioinfo.iconcologia.net/SNPstats) was performed to test Hardy-Weinberg equilibrium in controls. Generalized multifactor dimensionality reduction (GMDR) was adopted to screen the preferable interaction between eNOS SNPs and smoking.

RESULTS

The frequency for the rs1799983-T allele was 31.1% in CHD patients, which was significantly higher than that of 19.8% in controls (P < 0.05). The frequency for the rs891512-A allele was 28.8% in cases, which was also significantly higher than that of 20.1% in controls (P < 0.05). Logistic regression analysis showed that both rs1799983-T and rs891512-A alleles were related with increased risk of CHD, and the odds ratios (ORs) [95% confidence interval (CI)] were 1.71 (1.31-2.15) and 1.57 (1.14-2.07), respectively. High-order interactions were investigated among SNPs and environmental factors using the GMDR method. The data showed that a two-locus model (rs1799983 × smoking) had a testing accuracy of 0.60 (P = 0.001). We found that current smokers with rs1799983-GT or TT within eNOS gene have the highest CHD risk, compared to never smokers with rs1799983-GG genotype, OR (95% CI) = 2.74 (1.78-3.85), after covariates adjustment for age, gender, BMI, and alcohol drinking.

CONCLUSION

The rs1799983-T and rs891512-A alleles and interaction between rs1799983 and smoking were all risk factors of CHD.

Identifying potential biomarkers of nonalcoholic fatty liver disease via genome-wide analysis of copy number variation

BACKGROUND

The prevalence of Non-alcoholic fatty liver disease (NAFLD) is increasing and emerging as a global health burden. In addition to environmental factors, numerous studies have shown that genetic factors play an important role in the development of NAFLD. Copy number variation (CNV) as a genetic variation plays an important role in the evaluation of disease susceptibility and genetic differences. The aim of the present study was to assess the contribution of CNV to the evaluation of NAFLD in a Chinese population.

METHODS

Genome-wide analysis of CNV was performed using high-density comparative genomic hybridisation microarrays (ACGH). To validate the CNV regions, TaqMan real-time quantitative PCR (qPCR) was utilized.

RESULTS

A total of 441 CNVs were identified, including 381 autosomal CNVs and 60 sex chromosome CNVs. By merging overlapping CNVs, a genomic CNV map of NAFLD patients was constructed. A total of 338 autosomal CNVRs were identified, including 275 CNVRs with consistent trends (197 losses and 78 gains) and 63 CNVRs with inconsistent trends. The length of the 338 CNVRs ranged from 5.7 kb to 2.23 Mb, with an average size of 117.44 kb. These CNVRs spanned 39.70 Mb of the genome and accounted for ~ 1.32% of the genome sequence. Through Gene Ontology and genetic pathway analysis, we found evidence that CNVs involving nine genes may be associated with the pathogenesis of NAFLD progression. One of the genes (NLRP4 gene) was selected and verified by quantitative PCR (qPCR) method with large sample size. We found the copy number deletion of NLRP4 was related to the risk of NAFLD.

CONCLUSIONS

This study indicate the copy number variation is associated with NAFLD. The copy number deletion of NLRP4 was related to the risk of NAFLD. These results could prove valuable for predicting patients at risk of developing NAFLD.

An updated meta-analysis showed smoking modify the association of GSTM1 null genotype on the risk of coronary heart disease

Background Oxidative stress is considered to be involved in the pathogenesis of coronary heart disease (CHD). Glutathione-S-transferase (GST) enzymes play important roles in antioxidant defenses and may influence CHD risk. The present meta-analysis was performed to investigate the link between glutathione S-transferase M1 (GSTM1) null genotype and CHD and to get a precise evaluation of interaction between GSTM1 null genotype and smoking by the case-only design.

Methods PubMed and EMBASE databases were searched through 15 December 2020 to retrieve articles. Odds ratios (ORs) were pooled using either fixed-effects or random-effects models.

Results Thirty-seven studies showed that GSTM1 null genotype was associated with risk of CHD in total population, Caucasians and Asians (for total population, OR = 1.38, 95% confidence interval (CI): 1.15, 1.65; for Caucasians, OR = 1.34, 95% CI: 1.04, 1.72; for Asians, OR = 1.40, 95% CI: 1.11, 1.77). After adjustment for heterogeneity, these relationships were still significant. After adjustment for heterogeneity, case-only analysis of 11 studies showed a positive multiplicative interaction between GSTM1 null genotype and smoking (ever smoking vs. never smoking) (OR = 1.27, 95% CI: 1.08, 1.50; I² = 0%, P=0.553).

Conclusions The overall results indicated that GSTM1 null genotype was associated with a higher risk of CHD, and the association may be affected by smoking status. This is the first meta-analysis to prove a positive effect of the interaction between GSTM1 null genotype and smoking status on the risk of CHD. Well-designed studies are needed to investigate the possible gene–gene or gene–environment interactions.

Analysis for interaction between interleukin-35 genes polymorphisms and risk factors on susceptibility to coronary heart disease in the Chinese Han population

BACKGROUND

The relationship between IL-35 genes polymorphism and susceptibility to coronary heart disease has not been tested in the largest Han population in China. The aim of this study was to explore the effect of single nucleotide polymorphisms (SNPs) of interleukin-35 (IL-35) genes and its relationship with environment on the risk of coronary heart disease (CHD).

METHODS

We performed Hardy-Weinberg equilibrium test on the control group. The relationship between the four SNPs of IL-35 genes and the risk of coronary heart disease was studied by multivariate logistic regression. The best interaction was identified with generalized multifactor dimensionality reduction (GMDR). Logistic regression was used for investigation on association between four SNPs and CHD risk.

RESULTS

Logistic regression analysis showed that the C allele of rs428253 and the G allele of rs2243115 were independently correlated with increased risk of CHD, and adjusted ORs (95% CI) were 1.91 (1.28-2.64) and 1.80 (1.30-2.23), respectively. However, there was no significant association between CHD and rs4740 or rs568408. GMDR model indicated a best model for CHD risk consisted of rs428253 and current smoking, which scored 10/10 for both the sign test and cross-validation consistency (p = 0.010). Therefore, this overall multi-dimensional model had the highest cross-validation consistency, regardless of how the data were divided. This provided an evidence of gene-environment interaction effects. We also found that current smokers with rs428253-GC/CC genotype have the highest CHD risk, compared to never smokers with rs428253-GG genotype, OR (95% CI) = 3.04 (1.71-4.41), after adjustment for age, gender, hypertension, T2DM and alcohol consumption status.

CONCLUSIONS

In this study, the C allele of rs428253 and the G allele of rs2243115, and the interaction rs428253 and current smoking were correlated with increased risk of CHD.

Glutathione S-transferase gene polymorphisms (GSTT1 and GSTM1) and risk of schizophrenia: A case-control study in Chinese Han population

Schizophrenia (SCZ) is a chronic disability disorder related to oxidative stress. Glutathione S-transferase (GST) is a group enzyme that protects cells and tissues from oxidative stress damage. Among GSTs, GSTT1 and GSTM1 have well defined genetic polymorphisms. The purpose of our research was to explore the correlation between GSTT1 and GSTM1 polymorphism and SCZ risk in Chinese Han population.A total of 650 subjects (386 SCZ patients and 264 healthy individuals) were included in this case-control designed study. The GSTT1 and GSTM1 polymorphisms were analyzed by multiplex polymerase chain reaction (PCR). We explored the relationship between these 2 polymorphisms and the risk of SCZ.We found that the GSTT1 null genotype had a protective effect on the development of SCZ [odds ratio (OR) = 0.601, 95% confidence interval (95% CI) = 0.412-0.986, P = .031]. We also found that the combination of null genotypes of the GSTT1 and GSTM1 genes was made at a lower risk of SCZ (OR = 0.452, 95% CI = 0.238-0.845, P = .028). However, we found no correction between Positive and Negative Syndrome Scale score (PANSS) and GSTM1, GSST1 genotypes in SCZ patients.Our finding revealed that GSTT1 null polymorphisms may be related to the reduced risk of SCZ in Chinese Han population, and this risk was further reduced with the combination of GSTT1 null polymorphisms and GSTM1 null polymorphisms.

GST null polymorphisms may affect the risk of coronary artery disease: evidence from a meta-analysis

Background

Whether glutathione S-transferase (GST) null polymorphisms, namely GSTM1 null, GSTP1 null and GSTT1 null polymorphisms, influence the risk of coronary artery disease (CAD) or not remains unclear. Thus, the authors performed a meta-analysis to more robustly estimate associations between GST null polymorphisms and the risk of CAD by integrating the results of previous publications.

Methods

Medline, Embase, Wanfang, VIP and CNKI were searched comprehensively for eligible studies, and 45 genetic association studies were finally selected to be included in this meta-analysis.

Results

We found that GSTM1 null polymorphism was significantly associated with the risk of CAD in overall population (OR = 1.37, p = 0.003) and mixed population (OR = 1.61, p = 0.004), GSTP1 null polymorphism was significantly associated with the risk of CAD in overall population (OR = 1.23, p = 0.03), whereas GSTT1 null polymorphism was significantly associated with the risk of CAD in overall population (OR = 1.23, p = 0.02), Caucasians (OR = 1.23, p = 0.02) and East Asians (OR = 1.38, p < 0.0001).

Conclusions

This meta-analysis demonstrated that GSTM1 null, GSTP1 null and GSTT1 null polymorphisms were all significantly associated with an increased risk of CAD.

Association of GSTP1, GSTT1 and GSTM1 Gene Variants with Coronary Artery Disease in Iranian Population: A Case-Control Study

Background

Coronary artery disease (CAD) is a multifactorial disease that may be caused by the interaction between environmental and genetic risk factors. Glutathione S-transferases (GSTs) are known to participate in detoxification and metabolism of a wide range of xenobiotic compounds and oxidative stress products. Considering the interaction between environmental and genetic factors in CAD, we investigated the genetic polymorphisms of GSTM1, GSTT1, and GSTP1 in the Iranian population.

Patients and Methods

Two hundred and forty-four CAD cases and 281 healthy controls were studied. The genotype of GSTM1, GSTT1, and GSTP1 genes was determined by multiplex polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP) techniques. Multivariable logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals (CI). Multifactor dimensionality reduction (MDR) analysis was also carried out to analyze the gene–gene and gene–environment interaction.

Results

The genotype and allele distribution of the three variations were not significantly different between CAD patients and controls (p > 0.05). The subgroup analysis revealed no significant gene–gene interactions or gene–gene combination effects linked to CAD susceptibility. However, MDR analysis selected the GSTM, GSTT pairwise and three genes combination models associated with the susceptibility to CAD. In addition, its result revealed that smoking in combination with GSTM1 (two-way) and GSTT, GSTP (three-way) genes might increase the risk of CAD. Furthermore, a significant interaction between GSTT1-null polymorphism and dyslipidemia was found in multivariable logistic regression analyses in the gene–environmental interactions on CAD risk.

Conclusion

Our results suggest that the GSTM1, GSTT1 and GSTP1 genetic variations are not directly associated with the susceptibility to CAD in Iranian patients. Due to MDR results, there might be a non-linear association between interactions of two or three genes and smoking with CAD. There is also an association between CAD risk factors and GST variations, which requires supplementary confirmation with larger sample sizes.

Association of combined genetic variations in SOD3, GPX3, PON1, and GSTT1 with hypertension and severity of coronary artery disease

Oxidative stress plays a critical role in the pathophysiology of hypertension (HT) and the progression of atherosclerotic coronary artery disease (CAD). Genetic variations in superoxide dismutase (SOD), glutathione peroxidase 3 (GPX3), paraoxonase 1 (PON1) and glutathione S-transferase theta 1 (GSTT1) may modulate their gene functions, affecting protein functions. These changes could have an impact on the pathogenesis of HT and progression of CAD. The present study investigated the associations of individual and combined antioxidant-related gene polymorphisms with the incidence of HT and severity of CAD. Two study populations were enrolled. The HT-associated study comprised 735 control and 735 hypertensive subjects (mean age 59.3 ± 9.0 years), matched for age and sex. The CAD study, hospital-based subjects (mean age 62.1 ± 9.5 years), included 279 CAD patients and 165 non-CAD subjects. Gene polymorphisms were identified in genomic DNA using polymerase chain reaction (PCR)-based technique. Genetic variations were assessed for their associations with HT and severity of CAD. Antioxidant gene variants, SOD3 rs2536512-GG, GPX3 rs3828599-GG, PON1 rs705379-TT, and GSTT1^{-/- and +/-}, were independently associated with the incidence of HT. A combination of four HT-associated genotypes, as a genetic risk score (GRS), revealed an association of GRS 5 and GRS ≥ 6 with increased susceptibility to HT and CAD, and further with multivessel coronary atherosclerosis (multivessel CAD) compared with GRS 0-2 [respective ORs(95% CI) for GRS ≥ 6 = 2.37 (1.46-3.85), 3.26 (1.29-8.25), and 4.36 (1.36-14.0)]. Combined polymorphisms in these four antioxidant-related genes were associated with the incidences of HT and CAD, and with the severity of coronary atherosclerosis.

Association of genetic polymorphisms in SOD2, SOD3, GPX3, and GSTT1 with hypertriglyceridemia and low HDL-C level in subjects with high risk of coronary artery disease

Background

Oxidative stress modulates insulin resistant-related atherogenic dyslipidemia: hypertriglyceridemia (HTG) and low high-density lipoprotein cholesterol (HDL-C) level. Gene polymorphisms in superoxide dismutase (SOD2 and SOD3), glutathione peroxidase-3 (GPX3), and glutathione S-transferase theta-1 (GSTT1) may enable oxidative stress-related lipid abnormalities and severity of coronary atherosclerosis. The present study investigated the associations of antioxidant-related gene polymorphisms with atherogenic dyslipidemia and atherosclerotic severity in subjects with high risk of coronary artery disease (CAD).

Methods

Study population comprises of 396 subjects with high risk of CAD. Gene polymorphisms: SOD2 rs4880, SOD3 rs2536512 and rs2855262, GPX rs3828599, and GSTT1 (deletion) were evaluated the associations with HTG, low HDL-C, high TG/HDL-C ratio, and severity of coronary atherosclerosis.

Results

SOD2 rs4880-CC, SOD3 rs2536512-AA, rs2855262-CC, and GPX3 rs3828599-AA, but not GSTT1^-/- individually increased risk of HTG combined with low HDL-C level. With a combination of five risk-genotypes as a genetic risk score (GRS), GRS ≥ 6 increased risks of low HDL-C, high TG/HDL-C ratio, and HTG combined with low HDL-C, comparing with GRS 0–2 [respective adjusted ORs (95% CI) = 2.70 (1.24–5.85), 3.11 (1.55–6.23), and 5.73 (2.22–14.77)]. Gene polymorphisms, though, were not directly associated with severity of coronary atherosclerosis; high TG/HDL-C ratio was associated with coronary atherosclerotic severity [OR = 2.26 (95% CI [1.17–4.34])].

Conclusion

Combined polymorphisms in antioxidant-related genes increased the risk of dyslipidemia related to atherosclerotic severity, suggesting the combined antioxidant-related gene polymorphisms as predictor of atherogenic dyslipidemia.

Contributions of Interactions Between Lifestyle and Genetics on Coronary Artery Disease Risk

PURPOSE OF THE REVIEW

To summarize current knowledge on interactions between genetic variants and lifestyle factors (G×L) associated with the development of coronary artery disease (CAD) and prioritize future research.

RECENT FINDINGS

Genetic risk and combined lifestyle factors and behaviors have a log-additive effect on the risk of developing CAD. First, we describe genetic and lifestyle factors associated with CAD and then focus on G×L interactions. The majority of G×L interaction studies are small-scale candidate gene studies that lack replication and therefore provide spurious results. Only a few studies, of which most use genetic risk scores or genome-wide approaches to test interactions, are robust in number and analysis strategy. These studies provide evidence for the existence of G×L interactions in the development of CAD. Further G×L interactions studies are important as they contribute to our understanding of disease pathophysiology and possibly provide insights for improving interventions or personalized recommendations.

Peridinin Is an Exceptionally Potent and Membrane-Embedded Inhibitor of Bilayer Lipid Peroxidation

Antilipoperoxidant protein dysfunction is associated with many human diseases, suggesting that bilayer lipid peroxidation may contribute broadly to pathogenesis. Small molecule inhibitors of this membrane-localized chemistry could in theory enable better understanding and/or treatment of such diseases, but currently available compounds have important limitations. Many biological questions thus remain unanswered, and clinical trials have largely been disappointing. Enabled by efficient, building block-based syntheses of three atypical carotenoid natural products produced by microorganisms that thrive in environments of extreme oxidative stress, we found that peridinin is a potent inhibitor of nonenzymatic bilayer lipid peroxidation in liposomes and in primary human endothelial cells. We also found that peridinin blocks monocyte-endothelial cell adhesion, a key step in atherogenesis. A series of frontier solid-state NMR experiments with a site-specifically 13C-labeled isotopolog synthesized using the same MIDA boronate building block-based total synthesis approach revealed that peridinin is completely embedded within and physically spans the hydrophobic core of POPC membranes, maximizing its effective molarity at the site of the targeted lipid peroxidation reactions. Alternatively, the widely used carotenoid astaxanthin is significantly less potent and was found to primarily localize extramembranously. Peridinin thus represents a promising and biophysically well-characterized starting point for the development of small molecule antilipoperoxidants that serve as more effective biological probes and/or therapeutics.

Glutathione S-transferase π: a potential role in antitumor therapy

Glutathione S-transferase π (GSTπ) is a Phase II metabolic enzyme that is an important facilitator of cellular detoxification. Traditional dogma asserts that GSTπ functions to catalyze glutathione (GSH)-substrate conjunction to preserve the macromolecule upon exposure to oxidative stress, thus defending cells against various toxic compounds. Over the past 20 years, abnormal GSTπ expression has been linked to the occurrence of tumor resistance to chemotherapy drugs, demonstrating that this enzyme possesses functions beyond metabolism. This revelation reveals exciting possibilities in the realm of drug discovery, as GSTπ inhibitors and its prodrugs offer a feasible strategy in designing anticancer drugs with the primary purpose of reversing tumor resistance. In connection with the authors' current research, we provide a review on the biological function of GSTπ and current developments in GSTπ-targeting drugs, as well as the prospects of future strategies.

Glutathione S-transferase M1 and T1 polymorphisms, and their interactions with smoking on risk of low birth weight: a meta-analysis

Background: Published data regarding the association between glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) gene polymorphisms and risk of low birth weight (LBW) remains inconclusive, and data on the interactions between the two gene polymorphisms and smoking for LBW susceptibility is lacking. To clarify these associations, a meta-analysis was conducted.Methods: A comprehensive literature search was conducted in multiple databases until 11 January 2018. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using fixed or random effects model.Results: Thirty-eight studies from 17 articles concerning maternal and neonatal GSTM1 and GSTT1 gene polymorphism with LBW risk were included in this meta-analysis, and nine studies from five articles provided data of maternal tobacco exposure status during pregnancy. Maternal GSTM1 null genotype was associated with increased LBW risk (OR = 1.27, 95% CI: 1.12-1.45). There was a nonsignificant but positive association (OR = 1.19, 95% CI: 0.97-1.46) between the maternal GSTT1 null genotype and the LBW risk in the overall analysis. There was a null association between neonatal GSTM1 or GSTT1 polymorphism and LBW risk. There were significant associations between the maternal GSTM1 null and GSTT1 null genotype and LBW risk (for the former, OR = 3.85, 95% CI: 1.68-8.81; for the later, OR = 1.88, 95% CI: 1.01-3.50) in individuals with active smoking, respectively.Conclusion: Maternal GSTM1 and GSTT1 null genotypes, but not neonatal genotypes, are suggested to increase LBW susceptibility, and there are interactions between active smoking and these polymorphisms in the development of LBW.

GSTM1-null and GSTT1-active genotypes as risk determinants of primary open angle glaucoma among smokers

AIM

To evaluate glutathione transferase theta 1 and mu 1 (GSTT1 and GSTM1) polymorphisms as determinants of primary open angle glaucoma (POAG) risk, independently or in combination with cigarette smoking, hypertension and diabetes mellitus.

METHODS

A case-control study with 102 POAG patients and 202 age and gender-matched controls was carried out. Multiplex-polymerase chain reaction method was used for the analysis of GSTM1 and GSTT1 polymorphisms. The differences between two groups were tested by the t-test or χ² test. Logistic regression analysis was used for assessing the risk for disease development.

RESULTS

The presence of GSTM1-null genotype did not contribute independently towards the risk of POAG. However, individuals with GSTT1-active genotype were at almost two-fold increased risk to develop glaucoma (P=0.044) which increased up to 4.36 when combined with GSTM1-null carriers (P=0.024). When glutathione transferase (GST) genotypes were analyzed in association with cigarette smoking, hypertension and diabetes, only carriers of GSTT1-active genotype had significantly increased risk of POAG development in comparison with GSTT1-null genotype individuals with no history of smoking, hypertension and diabetes, respectively (OR=3.52, P=0.003; OR=10.02, P<0.001; OR=4.53, P=0.002).

CONCLUSION

The results obtained indicate that both GSTM1-null and GSTT1-active genotypes are associated with increased POAG risk among smokers, suggesting potential gene-environment interaction in glaucoma development.

Genetic susceptibility of glutathione S-transferase genes (GSTM1/T1 and P1) to coronary artery disease in Asian Indians

Genetic polymorphisms in glutathione S-transferase (GST) genes may modulate the risk of cardiovascular diseases. The objective of present study was to investigate the potential association between the polymorphisms of GSTM1/T1 and P1 genes and their influence on diverse clinical parameters and oxidative stress biomarkers in coronary artery disease (CAD) patients in Asian Indians. The present study includes 562 angiographically confirmed CAD patients and 564 healthy control subjects from the north Indian population. Anthropometric and clinical measurements were performed for all the participants. The oxidative stress biomarkers including malondialdehyde and total antioxidant capacity were also measured. The genotyping of the GSTM1/T1 and P1 genes was performed using the multiplex-PCR and PCR-RFLP methods. The CAD patients exhibit significantly high values of waist circumference, waist-to-hip ratio, body fat (%), glucose, triglycerides, and very low-density lipoprotein, and reduced high-density lipoprotein levels compared to control subjects (P < 0.001). Malondialdehyde levels were significantly enhanced, and the total antioxidant capacity was reduced in CAD patients compared to controls (P < 0.001). However, no significant difference in body mass index and total cholesterol levels were observed in CAD patients and control subjects. The frequencies of the GSTM1 and GSTM1/T1 null genotypes in the CAD patients were significantly higher than the control subjects. In contrast, the GSTT1(-) genotype frequencies were significantly lower in CAD patients than the controls. Logistic regression analysis of the data revealed the null genotype of GSTM1 and the GG genotype of the GSTP1 (313A/G) gene were associated with an approximately twofold enhanced risk of developing CAD, whereas GSTT1(-) plays a defensive role against CAD development in north Indians. Upon stratification of data according to the genotypes of the GSTM1/T1 and P1 genes, we did not find significant a difference among the various metabolic traits in CAD patients and controls. Our results suggest that oxidative damage induced by lipid peroxidation with reduced antioxidant capacity and genetic variants in GST genes (GSTM1/T1 and P1) may modify the risk of CAD development in Asian Indian population.

ROLE OF THIOLS IN OXIDATIVE STRESS

A well-regulated redox state is essential for normal physiological function and cellular metabolism. In most eukaryotic cells, protein cysteine thiols are most sensitive to fluctuations in the cellular redox state. Under normal physiological conditions, the cytosol has a highly reducing environment, which is due to high levels of reduced glutathione and complex system of redox enzymes that maintain glutathione in the reduced state. The reducing environment of the cytosol maintains most protein thiols in the reduced state; although some non-exposed cysteine could be present as disulfides. Upon physiological increase in cellular oxidants, such as due to growth factors, cytokines and thiol-disulfide exchange reactions, specific proteins could act as redox switches that regulate the conformation and activity of different proteins. This reversible post translational modification enables redox-sensitive dynamic changes in cell signaling and function. Physiological oxidative stress could lead to the formation of sulfenic acids, which are usually intermediate states of thiol oxidation that are converted to higher order oxidation states, intramolecular disulfides or mixed disulfides with glutathione. Such glutathiolation reactions have been found to regulate the function of several proteins involved in intracellular metabolism, signal transduction and cell structure. Excessive oxidative stress results in indiscriminate and irreversible oxidation of protein thiols, depletion of glutathione and cell death. Further elucidation of the relationship between changes in cell redox and thiol reactivity could provide a better understanding of how redox changes regulate cell function and how disruption of these relationships lead to tissue injury and dysfunction and the development of chronic diseases such as cancer and cardiovascular disease.

Glutathione transferases: substrates, inihibitors and pro-drugs in cancer and neurodegenerative diseases

Glutathione transferase classical GSH conjugation activity plays a critical role in cellular detoxification against xenobiotics and noxious compounds as well as against oxidative stress. However, this feature is also exploited by cancer cells to acquire drug resistance and improve their survival. As a result, various members of the family were found overexpressed in a number of different cancers. Moreover several GST polymorphisms, ranging from null phenotypes to point mutations, were detected in members of the family and found to correlate with the onset of neuro-degenerative diseases. In the last decades, a great deal of research aimed at clarifying the role played by GSTs in drug resistance, at developing inhibitors to counteract this activity but also at exploiting GSTs for prodrugs specific activation in cancer cells. Here we summarize some of the most important achievements reached in this lively area of research.

Association of glutathione S-transferase polymorphisms with the severity of mustard lung

Introduction: Glutathione S-transferase (GST) is one of the major detoxifiers in alveoli. Polymorphism in GST genes can influence the ability of individuals to suppress oxidative stress and inflammation. The present study was aimed to explore the hypothesis that the genetic polymorphisms of GST T1, M1 and P1 are associated with the severity of the mustard lung in the sulfur mustard-exposed individuals.

Methods: Blood samples were taken from 185 sulfur mustard-exposed and 57 unexposed subjects. According to the stage of the mustard lung, sulfur mustard-exposed patients were categorized in the mild/moderate and severe/very severe groups. A multiplex PCR method was conducted to identify GSTM1 and GSTT1 null genotypes. To determine the polymorphisms of GSTP1 in exon 5 (Ile105Val) and exon 6 (Ala114Val), RFLP-PCR method was performed.

Results: The frequency of GSTM1 homozygous deletion was significantly higher in the severe/very severe patients compared with the mild/moderate subjects (66.3% vs. 48%, P = 0.013). The GSTM1 null genotype was associated with the severity of mustard lung (adjusted odds ratio [OR], 2.257; 95% CI, 1.219-4.180). There was no significant association between GSTT1 and GSTP1 polymorphisms with the severity of the mustard lung.

Conclusion: The different distribution of GSTM1 null genotype in severe/very severe and mild/moderate groups indicated that the severity of the mustard lung might be associated with the genetic polymorphism(s).