Preliminary examination of polymorphisms of GSTM1, GSTT1, and GSTZ1 in relation to semen quality

Association of Glutathione Transferase M1, T1, P1 and A1 Gene Polymorphism and Susceptibility to IgA Vasculitis

Endothelial cell injury is a hallmark of IgA vasculitis (IgAV), possibly associated with various factors, including oxidative stress. Certain single nucleotide polymorphisms (SNPs) of glutathione S-transferases (GST) genes have been shown to increase susceptibility to oxidative stress. The objective of our study was to evaluate the gene polymorphisms of GSTM1, GSTT1, GSTP1, and GSTA1 in patients with IgAV. DNA was extracted from the blood of 124 children with IgAV and 168 age-matched healthy controls. A higher frequency of the GSTM1 null genotype was observed in patients with gastrointestinal (GI) system involvement compared to those without GI system involvement (51.5% vs. 28.6%, p = 0.011). Additionally, the GSTM1 null genotype was less prevalent (30.8% vs. 69.2%, p = 0.032), while the GSTP1 Val/Val genotype was significantly more prevalent in patients who developed urogenital complications (scrotal swelling) during the course of the disease (60% vs. 40%, p = 0.039). This study is the first to suggest an association between GSTM1 and GSTP1 polymorphisms and various phenotypes observed during the clinical course of IgAV in the pediatric population. However, it was performed on a national and likely single ethnic cohort, too small for definitive conclusions, so larger studies are needed to confirm this association.

Association of GSTM1 Polymorphism and Redox Potential with Idiopathic Male Infertility

BACKGROUND

The aim of this case-control study is to investigate possible associations between GSTM1 polymorphism and redox potential with sperm parameters.

METHODS

The study group consisted of sperm samples from 51 infertile men according to the WHO guidelines. The control group included 39 samples from men with normal seminal parameters. DNA was extracted and genotyped for the detection of the GSTM1 polymorphism. An evaluation of the static redox potential (sORP) using the MiOXSYSTM system was conducted.

RESULTS

The frequency of the GSTM1-null genotype was higher in infertile male individuals (60.78%) than in the controls (41.03%) and was associated with a 2.228-fold increased risk for male infertility. Fertile controls carrying the GSTM1-null genotype presented a lower percentage of typical sperm morphology and lower slow progressive motility. An excess of redox potential was observed in infertile males compared to fertile ones. In the control group higher sORP values had a positive correlation with immotility percentage and a negative correlation regarding total motility. In the study group sORP values had a negative correlation with total count, concentration, and slow progressive motility.

CONCLUSIONS

The present study highlights that GSTM1 polymorphism and redox potential affect both fertile and in fertile males. Moreover, redox potential levels could be used as an additional indicator along with the routine semen analysis for a comprehensive screening between infertile and fertile men.

Novel Mutations of TSPY1 Gene Associate Spermatogenic Failure Among Men

Etiology of male infertility is intriguing owing to complex genetic regulation of human spermatogenesis and ethnic variations in genetic architecture of human populations. The present study characterizes the role of Y chromosome specific spermatogenic regulator testis-specific protein Y-encoded 1 (TSPY1) gene mutation in spermatogenic failure. This case-control study includes 163 cases of spermatogenic failure and 175 age-matched fertile men as controls. We found five novel base substitutions, namely, MT162695, MN879413, MN889982, MN889983, MN719943, two deletions MN734578 and MN734579, three novel insertions MN719941, MN719942 and MN719944 through Sanger's dideoxy sequencing of TSPY1 gene reading frame. All these mutations exhibited strong association with male infertility. In silico analyses suggest prospective disruption in splice sites and alteration in different isoforms of TSPY1 transcripts and amino acid sequence in TSPY1 protein. The study provides novel evidence in favour of implication of TSPY1 gene in male fertility. The outcome sheds light to get insight into the issue of idiopathic male infertility in Bengali population.

Effect of glutathione S-transferase gene polymorphisms on semen quality in patients with idiopathic male infertility

OBJECTIVE

To investigate the relationship between glutathione S-transferase enzyme (GSTM1, T1, and P1) genetic variants and semen quality in men with idiopathic infertility.

METHODS

Sperm characteristics were measured using computer-assisted sperm analysis. The malondialdehyde (MDA), nitric oxide (NO), and total antioxidant capacity (TAC) activities were detected by spectroscopic analysis, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) was detected by enzyme-linked immunosorbent assay.

RESULTS

This study included 246 idiopathic infertile men and 117 controls. The GSTM1(-), T1(-), and M1/T1(-/-) genotype frequencies significantly differed between the groups. The GSTM1(-) and T1(-) genotypes in idiopathic infertile men negatively correlated with sperm concentration, motility, mitochondrial membrane potential, and other parameters. However, these genotypes positively correlated with the amplitude of the lateral head displacement and NO and 8-OHdG levels. The GSTT1(-) genotype positively correlated with mean angular displacement and MDA activity. GSTM1(-) and T1(-) had a synergistic effect on semen quality. Sperm motility, normal morphology, straightness, and TAC were lower and amplitude of lateral head displacement and MDA were higher in the GSTP1(A/G + G/G) group than in the GSTP1(A/A) group among men with idiopathic infertility.

CONCLUSIONS

GSTM1, T1, and P1 genetic variants may be risk factors for infertility by affecting the semen quality men with idiopathic oligoasthenospermia.

GSTO2 Isoforms Participate in the Oxidative Regulation of the Plasmalemma in Eutherian Spermatozoa during Capacitation

In addition to perinuclear theca anchored glutathione-s-transferase omega 2 (GSTO2), whose function is to participate in sperm nuclear decondensation during fertilization (Biol Reprod. 2019, 101:368–376), we herein provide evidence that GSTO2 is acquired on the sperm plasmalemma during epididymal maturation. This novel membrane localization was reinforced by the isolation and identification of biotin-conjugated surface proteins from ejaculated and capacitated boar and mouse spermatozoa, prompting us to hypothesize that GSTO2 has an oxidative/reductive role in regulating sperm function during capacitation. Utilizing an inhibitor specific to the active site of GSTO2 in spermatozoa, inhibition of this enzyme led to a decrease in tyrosine phosphorylation late in the capacitation process, followed by an expected decrease in acrosome exocytosis and motility. These changes were accompanied by an increase in reactive oxygen species (ROS) levels and membrane lipid peroxidation and culminated in a significant decrease in the percentage of oocytes successfully penetrated by sperm during in vitro fertilization. We conclude that GSTO2 participates in the regulation of sperm function during capacitation, most likely through protection against oxidative stress on the sperm surface.

Urinary Biomarker of Prenatal Exposure to Disinfection Byproducts, Maternal Genetic Polymorphisms in CYP2E1 and GSTZ1, and Birth Outcomes

The effects of disinfection byproducts (DBPs) on adverse birth outcomes remain unsettled. Maternal genetic variants in relation to DBP metabolism may modify this effect. Pregnant women during late pregnancy (n = 1306) were included from a Chinese cohort. Maternal urinary trichloroacetic acid (TCAA) was measured as a biomarker of DBP exposure. Maternal genotyping was conducted in cytochrome P450 2E1 (CYP2E1; rs2031920, rs3813867, and rs915906) and glutathione S-transferase zeta-1 (GSTZ1; rs7975). The associations between maternal urinary TCAA and birth outcomes and statistical interactions between maternal exposure and genetic polymorphisms were estimated. We found that maternal urinary TCAA levels were associated with decreased birth weight (P for trend = 0.003) and ponderal index (P for trend = 0.004). Interaction analyses showed that maternal urinary TCAA in association with decreased birth weight was observed only among subjects with CYP2E1 rs3813867 GC/CC versus GG (P_int = 0.07) and associations with decreased birth length, ponderal index, and gestational age were observed only among subjects with GSTZ1 rs7975 GA/AA versus GG (P_int = 0.07, 0.02, and 0.02, respectively). Our results suggested that prenatal DBP exposure was negatively associated with birth weight and ponderal index, and maternal genetic polymorphisms in CYP2E1 and GSTZ1 might modify these associations.

Glutathione-S-transferases M1/T1 gene polymorphisms and male infertility risk in Chinese populations: A meta-analysis

BACKGROUND

A meta-analysis was applied to evaluate the associations between the glutathione-S-transferases (GSTs) M1/T1 gene polymorphisms and male infertility in Chinese populations.

METHODS

A comprehensive search for articles was conducted from PubMed, Web of Science, Embase, China biology medical literature database (CBM), China National Knowledge Infrastructure (CNKI), VIP, and Chinese literature database(Wang fang) up to April 30, 2018. All of the statistical analyses were performed using Review Manager 5.3 and Stata 14.0.

RESULTS

Ten studies on GSTM1 gene polymorphism involving 3302 cases and 1959 controls, and ten studies on GSTT1 gene polymorphism involving 3048 cases and 1861 controls were included in this meta-analysis. Overall, the null genotype of GSTM1/GSTT1 was significantly related to male infertility risk in Chinese populations (GSTM1, OR = 1.35, 95% CI: 1.02-1.78; GSTT1, OR = 1.40, 95% CI: 1.15-1.70). In subgroup analyses stratified by infertility type, significant association was observed between GSTT1 null genotype and male infertility in both nonobstructive azoospermia (NOA) and oligoasthenozoospermia (OAT). However, the GSTM1 null genotype was associated with OAT, but not NOA in Chinese populations. The sensitivity analysis confirmed the reliability and stability of the meta-analysis.

CONCLUSION

Our meta-analysis supports that the GSTM1/GSTT1 null genotype might contribute to individual susceptibility to male infertility in Chinese populations.

Effect modification of CPY2E1 and GSTZ1 genetic polymorphisms on associations between prenatal disinfection by-products exposure and birth outcomes

BACKGROUND

Prenatal disinfection by-products (DBPs) exposure is linked with adverse birth outcomes. Genetic susceptibility to DBP metabolism may modify the exposure-outcome associations.

OBJECT

To investigate whether CYP2E1 and GSTZ1 genetic polymorphisms modified the associations of prenatal DBP exposures with adverse birth outcomes.

METHODS

Two biomarkers of DBP exposures including trihalomethanes (THMs) in blood and trichloroacetic acid (TCAA) in urine were determined among 426 pregnant women from a Chinese cohort study. CYP2E1 (rs2031920, rs3813867, and rs915906) and GSTZ1 (rs7975) polymorphisms in cord blood were genotyped. Statistical interactions between prenatal DBP exposures and newborns CYP2E1 and GSTZ1 polymorphisms on birth outcomes (birth weight, birth length, and gestational age) were examined by multivariable linear regression with adjustment for potential confounders.

RESULTS

We found that newborns CYP2E1 genetic polymorphisms (rs2031920 and rs3813867) modified the associations of maternal blood THMs or urinary TCAA levels with birth outcomes. However, these interactions were nonsignificant after Bonferroni correction for multiple comparisons, except for the interaction between maternal blood BrTHMs [sum of dibromochloromethane (DBCM), bromodichloromethane (BDCM), and bromoform (TBM)] and newborns CYP2E1 gene rs2031920 polymorphisms on birth weight (P for interaction = 0.003).

CONCLUSION

Newborns genetic variations of CYP2E1 rs2031920 may modify the impacts of prenatal BrTHM exposure on birth weight. This finding needs to be further confirmed.

Association of polymorphisms in genes coding for antioxidant enzymes and human male infertility

PURPOSE

Although oxidative stress is thought to be an important cause of male infertility, primarily due to DNA and cell membrane damage, little is known about the genetic causes underlying suboptimal function of the seminal enzymatic antioxidant system. The aim of this study was to investigate the relationship of four potentially functional polymorphisms associated with oxidative stress pathway genes (superoxide dismutase-SOD2 lle58Thr and SOD2 rs4880, catalase-CAT C-262T, glutathione peroxidase 1-GPX1 Pro200Leu) and two null variants of the glutathione S transferase (GSTT and GSTM) genes and infertility risk.

METHODS

A case control study was conducted on 313 infertile patients and 80 fertile donors. Each ejaculate was subjected to a seminal analysis that included the classical parameters seminal volume, sperm concentration, sperm motility, and sperm morphology, as well as sperm DNA fragmentation (patients only). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR multiplex methods were carried out for genotyping.

RESULTS

Statistically significant differences were found between fertile donors and infertile patients for SNP CAT C-262T; the CC genotype was related with a twofold increased risk of infertility (odds ratio [OR] = 2.262; 95% confidence interval [CI] = 1.369-3.733; P = 0.001), whereas the CT genotype was associated with a protective effect (OR = 0.401; 95% CI = 0.241-0.667; P = 0.001). Surprisingly, the SOD2 Ile58ssThr SNP was not represented in the sample population, so its frequency in the current population frequenting fertility clinics in Madrid may be very low.

CONCLUSIONS

Our results suggest that the CAT SNP C-262T is potentially associated with an increased risk of male infertility.

Associations between sperm quality, DNA damage, and CYP1A1, GSTT1 and GSTM1 polymorphisms with 1-hydroxypyrene urinary levels in men occupationally exposed to polycyclic aromatic hydrocarbons

PURPOSE

During recent decades, several reports have suggested a decrease in semen quality and DNA damage due in part to environmental toxicants and industrial chemicals. Among these xenobiotics, polycyclic aromatic hydrocarbons (PAHs) are of particular concern because of their remarkable mutagenic and carcinogenic properties and because several experimental and epidemiological studies have reported adverse effects of PAHs on male reproductive health and DNA structure. The aim of the study was to evaluate the association between 1-hydroxypyrene (1-OHP) urinary levels and sperm quality, DNA damage and the frequency of CYP1A1, GSTT1, and GSTM1 polymorphisms.

METHODS

Semen, urine and blood samples were taken for sperm-quality assessment, 1-OHP urinary level measurement, DNA damage evaluation and polymorphism frequency analysis of three genes implicated in PAH metabolism in a total of 70 Mexican subjects exposed and nonexposed to PAHs.

RESULTS

A significant decrease in sperm quality and increased DNA damage were registered in occupationally exposed volunteers. Polymorphisms modified the 1-OHP urinary levels; however, no associations were found between them. Inverse associations were registered between the sperm concentration/mL and 1-OHP levels and between tail lengths and the GSMT1 null genotype.

CONCLUSIONS

Our data showed an inverse association between 1-OHP urinary levels and both sperm quality and the DNA integrity. Additionally, the heterozygote variants of CYP1A1-m1 and CYP1A1-m2 significantly increased the urinary excretion of 1-OHP, and the GSTM1 null variant was inversely associated with the comet parameters evaluated.

Interactions between CYP2E1, GSTZ1 and GSTT1 polymorphisms and exposure to drinking water trihalomethanes and their association with semen quality

Trihalomethanes (THMs) have been reported to be associated with altered semen quality, and this association may be modified by inherited differences in cytochrome P450 (CYP2E1) and glutathione S-transferase (GSTZ1 and GSTT1), which metabolize THMs. We conducted a cross-sectional study to examine the interactions between CYP2E1, GSTZ1 and GSTT1 polymorphisms and exposure to THMs on semen quality among 401 men from the Reproductive Center of Tongji Hospital in Wuhan China. The baseline blood concentrations of four individual THMs, chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM) and bromoform (TBM), were measured as biomarkers of exposure to drinking water THMs. Genotypes were determined by real-time PCR, and semen-quality parameters were evaluated according to the World Health Organization guidelines. GSTT1 genotype significantly modified the association between exposure to Br-THMs (sum of BDCM, DBCM and TBM) and below-reference sperm motility (Pint=0.02). Men with above-median blood Br-THM levels had an increased odds ratio (OR) of below-reference sperm compared to men with below-median blood Br-THM levels (OR=2.15, 95% CI: 1.11, 4.19) in the GSTT1 null genotype only. In addition, we found that men with a TT of CYP2E1 rs 915,906 had higher blood TCM and TTHM (sum of TCM, BDCM, DBCM and TBM) concentrations than men with a CT/CC of CYP2E1 rs 915,906. Our results suggest that GSTT1 polymorphisms modify Br-THM exposure relation with semen quality, and CYP2E1 polymorphisms are associated with internal levels of exposure to THMs.

Association of polymorphisms in glutathione S-transferase genes (GSTM1, GSTT1, GSTP1) with idiopathic azoospermia or oligospermia in Sichuan, China

The reported effects of the glutathione S-transferase (GSTs) genes (GSTM1, GSTT1, and GSTP1) on male factor infertility have been inconsistent and even contradictory. Here, we conducted a case-control study to investigate the association between functionally important polymorphisms in GST genes and idiopathic male infertility. The study group consisted of 361 men with idiopathic azoospermia, 118 men with idiopathic oligospermia, and 234 age-matched healthy fertile male controls. Genomic DNA was extracted from the peripheral blood, and analyzed by polymerase chain reaction and restriction fragment length polymorphism analysis. There was a significant association between the GSTP1 variant genotype (Ile/Val + Val/Val) with idiopathic infertility risk (odds ratio [OR]: 1.53; 95% confidence interval [CI]: 1.11–2.11; P = 0.009). Similarly, a higher risk of infertility was noted in individuals carrying a genotype combination of GSTT1-null and GSTP1 (Ile/Val + Val/Val) (OR: 2.17; 95% CI: 1.43–3.31; P = 0.0002). These results suggest an increased risk of the GSTP1 variant genotype (Ile/Val + Val/Val) for developing male factor infertility. Our findings also underrate the significance of the effect of GSTM1 and/or GSTT1 (especially the former) in modulating the risk of male infertility in males from Sichuan, southwest China.

Missense mutation in glutathione-S-transferase M1 gene is associated with sperm motility and ATP content in frozen-thawed semen of Holstein-Friesian bulls

Glutathione-S-transferase genes (GSTs) encode enzymes that are involved in detoxification and neutralization of reactive oxygen species (ROS) in male reproductive system and play protective role during spermatogenesis. The aim of the study was to evaluate whether C/G missense mutation (rs135955605) within glutathione-S-transferase M1 (GSTM1) gene is associated with selected parameters of frozen-thawed semen in 309 Holstein-Friesian bulls. Single nucleotide substitution C/G was identified by amplification of GSTM1 gene fragment followed be digestion with restriction enzyme DdeI. Bulls with GG genotype were the most frequent (67.96%), in comparison to CC (2.59%) and GC (29.45%). Significant associations were found between GSTM1 genotypes and ATP content and total sperm motility. Bulls with GG genotype had the highest values for both traits. Rare variant C of GSTM1 was associated with significant decrease of sperm motility and ATP content. Our results demonstrate that C/G missense mutation within GSTM1 gene is involved in bull sperm quality.

Genome-wide association study for sperm concentration in Holstein-Friesian bulls

The aim of the study was to screen the entire bull genome to identify markers and candidate genes underlying sperm concentration. The analysed data set originates from a population of 877 Polish Holstein-Friesian bulls. Based on sperm concentration value, two extreme groups of bulls were created: Low (L, n = 126) and High (H, n = 140). Each bull was genotyped using the Illumina BovineSNP50 BeadChip. Genome-wide association analysis was performed with the use of GoldenHelix SVS7 software. An additive model with a Cohran-Armitage test, Correlation/Trend adjusted by a Bonferroni test, was used to estimate the effect of SNP marker for sperm concentration. Thirteen markers reached genome-wide significance. The most significant SNPs were located on chromosome 3 (rs109154964 and rs108965556), 14 (rs41621145) and 18 (rs41615539), in the close vicinity of protein arginine methyltransferase 6 (PRMT6), Sel1 repeat containing 1 (SELRC1), triple QxxK/R motif containing (TRIQK) and zinc finger homeobox 3 (ZFHX3) genes, respectively. For three other candidate genes located close to significant markers (within a distance of ca 1 Mb), namely histone deacetylase 9 (HDAC9), an inhibitor of DNA binding 2 (ID2) and glutathione S-transferase theta 1 (GSTT1), their potential role in the production of male germ cells was confirmed in earlier studies. Six additional candidate genes (Vav3, GSTM1, CDK5, NOS3, PDP1 and GAL3ST1) were suspected of being significantly associated with sperm concentration or semen biochemistry. Our results indicate the genetic complexity of sperm concentration but also open the possibility for finding causal polymorphism useful in marker-assisted selection.

The Enzymatic Antioxidant System of Human Spermatozoa

The ejaculated spermatozoon, as an aerobic cell, must fight against toxic levels of reactive oxygen species (ROS) generated by its own metabolism but also by other sources such as abnormal spermatozoa, chemicals and toxicants, or the presence of leukocytes in semen. Mammalian spermatozoa are extremely sensitive to oxidative stress, a condition occurring when there is a net increase in ROS levels within the cell. Opportunely, this specialized cell has a battery of antioxidant enzymes (superoxide dismutase, peroxiredoxins, thioredoxins, thioredoxins reductases, and glutathione s-transferases) working in concert to assure normal sperm function. Any impairment of the antioxidant enzymatic activities will promote severe oxidative damage which is observed as plasma membrane lipid peroxidation, oxidation of structural proteins and enzymes, and oxidation of DNA bases that lead to abnormal sperm function. Altogether, these damages occurring in spermatozoa are associated with male infertility. The present review contains a description of the enzymatic antioxidant system of the human spermatozoon and a reevaluation of the role of its different components and highlights the necessity of sufficient supply of reducing agents (NADPH and reduced glutathione) to guarantee normal sperm function.

Comparative analysis of Mafriwal (Bos taurus × Bos indicus) and Kedah Kelantan (Bos indicus) sperm proteome identifies sperm proteins potentially responsible for higher fertility in a tropical climate

The fertility of zebu cattle (Bos indicus) is higher than that of the European purebred (Bos taurus) and crossbred (Bos taurus × Bos indicus) cattle in tropical areas. To identify proteins related to the higher thermo-tolerance and fertility of Zebu cattle, this study was undertaken to identify differences in sperm proteome between the high fertile Malaysian indigenous zebu cattle (Kedah Kelantan) and the sub-fertile crossbred cattle (Mafriwal). Frozen semen from three high performance bulls from each breed were processed to obtain live and pure sperm. Sperm proteins were then extracted, and two-dimensional gel electrophoresis performed to compare proteome profiles. Gel image analysis identified protein spots of interest which were then identified by liquid chromatography mass spectrometry quadrupole time-of-flight (LC MS/MS Q-TOF). STRING network analysis predicted interactions between at least 20 of the identified proteins. Among the identified proteins, a number of motility and energy related proteins were present in greater abundance in Kedah Kelantan. Sperm motility evaluation by Computer Assisted Semen Analysis (CASA) confirmed significantly higher motility in Kedah Kelantan. While results from this study do identify proteins that may be responsible for the higher fertility of Kedah Kelantan, functional characterization of these proteins is warranted to reinforce our understanding of their roles in sperm fertility.

Association between three genetic polymorphisms of glutathione S-transferase Z1 (GSTZ1) and susceptibility to bipolar disorder

The association between polymorphisms of glutathione S-transferase Z1 (GSTZ1) and susceptibility to bipolar disorder (BPD) is investigated. This study was performed on 228 BPD patients and 234 control subjects. Among early-onset patients, the variant alleles of Glu32Lys and G-1002A increased BPD susceptibility. The haplotype "-1002G, 32Glu, 42Gly" versus the other haplotypes was significantly decreased among early-onset patients compared to controls (P=0.016).

Susceptibility to breast cancer and three polymorphisms of GSTZ1

Glutathione S-transferases class zeta (GSTζ) is involved in the detoxification of xenobiotic compounds and catalyzes the biotransformation of a variety of α-haloacids including dichloroacetic acid and chlorofluoroacetic acid. It has been reported that, in mice, deficiency of Gstz1 (a member of GSTζ) resulted in the generation of a constant level of oxidative stress. The present study was carried out to investigate the association between genetic polymorphisms of GSTZ1 (in promoter site G-1002A and in coding sites Glu32Lys and Gly42Arg) and risk of breast cancer. We included 106 females with breast cancer and 106 healthy females frequency matched for age. The study polymorphisms were not associated with risk of breast cancer (p>0.05). The polymorphisms of GSTZ1 showed strong linkage disequilibrium among cancer patients and control subjects (p<0.0001). There was no significant difference between cancer patients and controls for frequencies of the GSTZ1 haplotypes (p>0.05). It seems there is no meaningful relationship between the genetic polymorphisms of GSTZ1 and risk of breast cancer.