Xenobiotic Biotransformation Enzymes Research Articles

Association of polymorphic variants of genes of xenobiotic biotransformation enzymes with susceptibility to pulmonary tuberculosis, taking into account gender features

Aim of the study was to investigate susceptibility to pulmonary tuberculosis in men and women depending on polymorphism of genes of xenobiotic biotransformation enzymes NAT2 (590G> A (rs1799930)), CYP2E1 (9896C> G (rs2070676)), ABCB1 (3435T> C (rs1045642)), GSTM1 (E/D) and GSTT1 (E/D). Material and methods. The study included 335 patients with pulmonary tuberculosis aged 18 to 65 years (212 patients with newly diagnosed pulmonary tuberculosis and 123 people with chronic pulmonary tuberculosis receiving intensive phase of chemotherapy). Statistical data processing was carried out on a personal computer using IBM SPSS Statistics 26 and MS Excel 2013 software packages. The control group consisted of relatively healthy individuals without chronic diseases. Genotyping of polymorphisms NAT2 (590G>A (rs1799930)), CYP2E1 (9896C>G (rs2070676)), ABCB1 (3435T>C (rs1045642)) and extended deletions GSTM1 (E/D), GSTT1 (E/D) was performed using real time PCR. Results. It has been established that the genotype EЕ of GSTT1 gene identified in 89.1 % men was statistically significantly associated with increased susceptibility to pulmonary tuberculosis, while the genotype DD of the GSTT1 gene (10.9 % cases) was associated with reduced susceptibility. A similar trend is observed in women: the greatest susceptibility to pulmonary tuberculosis is characteristic for the genotype ЕЕ GSTT1 gene (87.2 %), the least (12.8 %) – for the DD genotype. Conclusions. It is advisable to introduce genotyping of genes of xenobiotic biotransformation enzymes into the practice of a phthisiologist in order to develop measures to improve the effectiveness of prevention and treatment of patients with pulmonary tuberculosis.

Polymorphism of xenobiotic biotransformation enzyme genes and their role in early pregnancy loss

Considering the progressive decrease in the number of women of fertile age, as well as children and adolescents, the primary medical and social task at the present stage is to preserve the reproductive health and life of women, preserving every desired pregnancy. The concept of demographic policy of the Russian Federation for the period until 2025 defines the global national goals, i.e. to increase the total fertility rate by 1.5 times, to reduce maternal and infant mortality by at least 2 times, and to improve the reproductive health of women, children and adolescents. Today every fifth desirable pregnancy ends in early loss, and the rate of miscarriage does not tend to decrease and, in fact, increases every year. Carriage of susceptibility or candidate genes can alter the course of biochemical processes in women and cause early pregnancy losses. According to the literature, the cytochrome P-450 gene (CYP1A1, CYP1B1), xenobiotic detoxification genes (GSTT1, GSTM1, GSTP1) and many others are recognized as candidate genes (genetic markers) associated with reproductive losses. Adverse pregnancy outcome is usually multifactorial; in turn, the combination of polymorphic variants of different candidate genes can increase the risk of early losses. A detailed study of the role of candidate genes with clarity and confirmation of the interest of candidate genes in the development of pregnancy loss is undeniable. In this regard, the interest of many researchers in studying the polymorphism of genes of the xenobiotic biotransformation enzyme system as one of the causal factors of pregnancy failure is understandable. The study of this group of genes is of particular relevance in regions with developed industry and high anthropogenic load. The article is devoted to the analysis of the existing data of foreign and domestic literature sources concerning the relationship between polymorphism of xenobiotic biotransformation system genes and reproductive losses.

Oxytetracycline-induced inflammatory process without oxidative stress in blue mussels Mytilus trossulus

Potentially harmful compounds including pharmaceuticals are commonly found in marine waters and sediments. Amongst those, antibiotics and their metabolites are detected worldwide in various abiotic (at concentrations as high as µg/L) and biotic matrices at ng/gram of tissue, posing a risk to non-target species exposed to them such as blue mussels. Amongst those, oxytetracycline (OTC) belongs to the most detected antibiotics in the marine environment. In this work, we concentrated on studying the potential induction of oxidative stress, activation of cellular detoxification processes (including Phase I and Phase II xenobiotic biotransformation enzymes) and multixenobiotic resistance pumps (Phase III) as well as changes in the aromatisation efficiency in Mytilus trossulus exposed to 100 μg/L OTC. Our results show that 100 µg/L OTC concentration did not provoke cellular oxidative stress and did not affect the expression of genes involved in detoxification processes in our model. Moreover, no effect of OTC on aromatisation efficiency was found. Instead, phenoloxidase activity measured in haemolymph was significantly higher in OTC exposed mussels than in those from the control (30.95 ± 3.33 U/L and 17.95 ± 2.75 U/L, respectively). OTC exposed mussels were also characterised by a tissue-dependant activation of major vault protein (MVP) gene expression (1.5 times higher in gills and 2.4 times higher in the digestive system) and a decreased expression of the nuclear factor kappa B-a (NF-κB) gene (3.4 times lower in the digestive system) when compared to those from the control. Additionally, an elevated number of regressive changes and inflammatory responses in tissues such as gills, digestive system and mantle (gonads) was observed underlining the worsening of bivalves’ general health. Therefore, instead of a free-radical effect of OTC, we for the first time describe the occurrence of typical changes resulting from antibiotic therapy in non-target organisms like M. trossulus exposed to antibiotics such as OTC.

Predictors of the effectiveness of treatment of tuberculosis patients with the development of the COVID-19 pandemic in the region of the Russian Federation

With an unstable epidemic situation for tuberculosis, with the development of a pandemic of another etiology, the importance of effective treatment of the disease increases. The results of observation of 326 patients were used and the influence of individual predictors of efficacy, including individual gene polymorphisms of xenobiotic biotransformation enzymes and patient adherence to treatment were analyzed. The value of the patient’s commitment to treatment as a predictor of effectiveness has been established, it is justified and necessary to use it to correct the main course of treatment. When consulting and managing patients with tuberculosis as a multifactorial disease, it is recommended to use methods of testing the polymorphism of genes of xenobiotic biotransformation enzymes in order to predict possible complications and the effectiveness of treatment, followed by the appointment of individual therapeutic and preventive measures.

РОЛЬ ПОЛИМОРФИЗМОВ ГЕНОВ СИСТЕМЫ БИОТРАНСФОРМАЦИИ КСЕНОБИОТИКОВ И АНТИОКСИДАНТНОЙ ЗАЩИТЫ В РАЗВИТИИ ДИАБЕТИЧЕСКОЙ НЕФРОПАТИИ

Introduction.The main etiopathogenetic mechanisms of the development of multifactorial diseases are genetic predisposition and environmental factors. A special role in the prognosis of type 1 diabetes mellitus is played by diabetic nephropathy, which leads to chronic kidney disease in its outcome. In the conditions of modern technogenic civilization, it is believed that the most significant contribution to the formation of predisposition to socially significant human diseases can be made by genes of enzymes of protective and adaptive systems of the body – these are, first of all, genes of enzymes of antioxidant protection and biotransformation of xenobiotics. The aim of the study was to study the role of polymorphic variants of genes of the xenobiotic biotransformation system and antioxidant protection (G681A in the CYP2C19 gene; G1293C in the CYP2E1 gene) in the development of diabetic nephropathy in patients with type 1 diabetes mellitus. Material and methods. The study included patients with type 1 diabetes mellitus (50 people) and healthy individuals (20 people). Molecular-genetic, clinical-laboratory and biochemical research methods were used. The reliability of differences in the distribution of genotype frequencies between groups of patients and healthy individuals was assessed by the test2, by the method of conjugate tables (four-field table). Results and discussion. The activity of the processes of free radical oxidation and lipid peroxidation increases many times in type 1 diabetes mellitus, which is confirmed in our study by an increase in the content of malondialdehyde products against the background of an increase in the activity of enzymes of the antioxidant defense system. This is especially evident in individuals carrying heterozygous polymorphism of the CYP2C19 (G681A) and CYP2E1 (G1293C) genes, which is also combined with a more pronounced decrease in kidney function in these patients compared with carriers of other polymorphic variants of the studied genes. Conclusion. Heterozygous polymorphism of the CYP2C19 (G681A) and CYP2E1 (G1293C) genes in combination with increased activity of antioxidant defense enzymes and xenobiotic biotransformation enzymes leads to a more severe course of diabetic nephropathy in patients with type 1 diabetes mellitus.

THE ROLE OF HEREDITARY PREDISPOSITION (POLYMORPHIC MARKERS OF GLUTATHIONE-S-TRANSFERASE, CATALASE, ENDOTHELIAL NITROGEN OXIDE SYNTHASE GENES) AND SOME ADVERSE ENVIRONMENTAL FACTORS IN THE DEVELOPMENT OF BRONCHO-OBSTRUCTIVE PATHOLOGY IN CHILDREN LIVING IN RADIOACTIVELY CONTAMINATED AREAS.

summarizing the results of many years of research by the authors on the influence of gene polymorphisms encoding xenobiotic biotransformation enzymes (GSTТ1, GSTM1, GSTР1), antioxidant protection (С^262Т of the catalase gene), endothelial nitric oxide synthase (4a/4b VNTR polymorphism of the eNOS gene), and some environmental factors on the occurrence of broncho-obstructive disorders and the development of bronchial asthma in children, residents of radioactively contaminated areas. The examined school-aged children were residents of radioactively RCA who had no clinical signs of respiratory pathology. Deletion polymorphism of catalase gene (CAT C^262T), polymorphism of glutathione-S-transferase gene (GSTТ1, GSTM1, GSTР1) and the polymorphism in the 4th intron (4a/4b) of the eNOS gene were studied in the molecular genetics laboratory of the State Institution «Reference Center for Molecular Diagnostics of Public Health Ministry of Ukraine». Molecular genetic studies were performed by polymerase chain reaction. The study of the ventilation lung capacity was carried out by the method of computer spirometry based on the data of the «flow-volume» loop analysis. A pharmacological inhalation test with a bronchodilator drug which affects the β2-adrenergic receptors of the lungs was used to detect early changes in the ventilatory lung capacity - bronchial hyperreactivity. One of the leading mechanisms, due to which the implementation of hereditary predisposition to bronchial asthma in children living in radioactively contaminated areas is the polymorphism of certain genes of glutathione-S-transferase, catalase, endothelial nitric oxide synthase. With such polymorphic variants of the GST genes, isoforms of enzymes with reduced activity are produced, which limits their ability to effectively neutralize free radicals, which are formed in excess when free radical oxidation processes are activated due to the constant intake of radionuclides with a long half-life into the body of children. Unfavorable factors that increase the risk of developing broncho-obstructive disorders and the likelihood of their implementation in the form of bronchial asthma in children, residents of radioactively contaminated areas, have been identified. It has been established that among them the leading role is played by hereditary predisposition to this disease. On the part of the child, such negative factors were unfavorable conditions of intrauterine development, the presence of signs of exudative-catarrhal diathesis, manifestations of allergies and frequent respiratory diseases from the first months of life.

Transcriptome responses in copepods Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus exposed to phenanthrene and benzo[a]pyrene.

Arctic and sub-arctic pelagic organisms can be exposed to effluents and spills from offshore petroleum-related activities and thus it is important to understand how they respond to crude oil related contaminants such as polycyclic aromatic hydrocarbons (PAHs). The copepod species Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus represent key links in the arctic marine food web. We performed a transcriptome analysis of the three species exposed to phenanthrene (Phe) and benzo[a]pyrene (BaP) representing low and high molecular weight PAHs, respectively. Differential expression of several genes involved in many cellular pathways was observed after 72h exposure to Phe (0.1μM) and BaP (0.1μM). In C. finmarchicus and C. glacialis, the exposure resulted in up-regulation of genes encoding enzymes in xenobiotic biotransformation, particularly the phase II cytosolic sulfonation system that include 3'-phosphoadenosine 5'-phosphosulfate synthase (PAPSS) and sulfotransferases (SULTs). The sulfonation pathway genes were more strongly induced by BaP than Phe in C. finmarchicus and C. glacialis but were not affected in C. hyperboreus. However, a larger number of genes and pathways were modulated in C. hyperboreus by the PAHs including genes encoding xenobiotic biotransformation and lipid metabolism enzymes, suggesting stronger responses in this species. The results suggest that the cytosolic sulfonation is a major phase II conjugation pathway for PAHs in C. finmarchicus and C. glacialis. Some of the biotransformation systems affected are known to be involved in metabolism of endogenous compounds such as ecdysteroids, which may suggest potential interference with physiological and developmental processes of the copepod species.

Association of Polymorphic Gene Variants of Xenobiotic Biotransformation Enzymes with Lung Tissue Destruction in Tuberculosis Patients

The objective: to investigate the association of polymorphic gene variants of xenobiotic biotransformation enzymes (NAT2, CYP2E1, ABCB1, GSTM1, GSTT1) and cytokines (IL1B, IL-4, IL-10, TNF) with lung tissue destruction in pulmonary tuberculosis patients.Subjects and Methods. An ethnically homogeneous population sample of unrelated individuals of Slavic nationalities (mainly Russians) living in Kursk Oblast suffering from new pulmonary tuberculosis was examined.Results. New pulmonary tuberculosis with no destructive changes in the lungs was associated with the EE genotype of the GSTM1 gene (p < 0.0001) in 89.5%, while the DD genotype of the GSTM1 gene (p < 0.0001) was associated with the presence of destructive changes in the lungs in 56.1% of cases; the dominant GG genotype of the TNF-α gene was associated with destructive changes in the lungs in 93.3% (p = 0.027), and the recessive GA genotype of the TNF-α gene was associated with no destructive changes in the lungs in 71.9% (p = 0.027).

Association of polymorphic gene variants of xenobiotic biotransformation enzymes with susceptibility to pulmonary tuberculosis

The objective: to investigate the relationship of polymorphic variants of genes of xenobiotic biotransformation metabolism enzymes (NAT2 (590G>A (rs1799930)), CYP2E1 (9896C>G (rs2070676)), ABCB1 (3435T>C (rs1045642)), GSTM1 (E/D), GSTT1 (E/D) with the risk of pulmonary tuberculosis.Subjects and Methods. Within the framework of this study, a population sample of unrelated 1081 individuals of Slavic nationalities (mainly Russians) living in the territory of Kursk Oblast was used.Results. The del/del (D/D) GSTM1 genotype was associated with an increased risk of developing tuberculosis, while carrying the del/del (D/D) GSTT1 genotype was associated with a lower risk of developing the disease. Polymorphism 3435T>C ABCB1 (TC genotype) was associated with increased susceptibility to pulmonary tuberculosis in the codominization model, while TT+TC genotypes had the same association in the dominance model.

Polymorphisms in DNA Repair and Xenobiotic Biotransformation Enzyme Genes and Lung Cancer Risk in Coal Mine Workers.

Background: Currently coal mining employs over 7 million miners globally. This occupational setting is associated with exposure to dust particles, heavy metals, polycyclic aromatic hydrocarbons and radioactive radon, significantly increasing the risk of lung cancer (LC). The susceptibility for LC is modified by genetic variations in xenobiotic detoxification and DNA repair capacity. The aim of this study was to investigate the association between GSTM1 (deletion), APEX1 (rs1130409), XPD (rs13181) and NBS1 (rs1805794) gene polymorphisms and LC risk in patients who worked in coal mines. Methods: The study included 639 residents of the coal region of Western Siberia (Kemerovo region, Russia): 395 underground miners and 244 healthy men who do not work in industrial enterprises. Genotyping was performed using real-time and allele-specific PCR. Results: The results show that polymorphisms of APEX1 (recessive model: ORadj = 1.87; CI 95%: 1.01–3.48) and XPD (log additive model: ORadj = 2.25; CI 95%: 1.59–3.19) genes were associated with increased LC risk. GSTM1 large deletion l was linked with decreased risk of LC formation (ORadj = 0.59, CI 95%: 0.36–0.98). The multifactor dimensionality reduction method for 3-loci model of gene–gene interactions showed that the GSTM1 (large deletion)—APEX1 (rs1130409)—XPD (rs13181) model was related with a risk of LC development. Conclusions: The results of this study highlight an association between gene polymorphism combinations and LC risks in coal mine workers.

Факторы риска формирования хронического полипозного риносинусита у детей с муковисцидозом

The investigation of the pathogenesis of chronic rhinosinusitis in patients with cystic fibrosis (CF) and analysis of molecular biomarkers can promote the development of tailored approaches to its treatment and prevention. Objective. To analyze associations between sinonasal polyposis and genetic polymorphisms of the xenobiotic metabolizing enzymes (XMEs) in CF patients. Patients and methods. We performed a retrospective comparative analysis of 145 CF patients from the Russian Federation (RF) and 82 patients from the Republic of Belarus (RB). Patients provided blood samples that were later used for DNA extraction; clinical information was collected for all study participants. The diagnosis was based on the guidelines of the European and Russian Consensus. This was a case-control study. The XME gene polymorphisms were assessed using polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) or amplified fragment length polymorphism (AFLP) analysis with special primers. The following genes and polymorphic variants were chosen for the study: phase I (CYP2C9*3 (rs1057910; c.1075A>C; I359L), CYP2C9*2 (rs1799853; c.430C>T; R144C), CYP2C19*2 (rs4244285; c.681G>A), CYP2C19*3 (rs4986893; c.636G>A; W212X), CYP2D6*4 (rs3892097; c.1846G>A), CYP3A4*3 (rs4986910; M445T; c.1334T>C), CYP3A4*1B (rs2740574; c.-392C>T); phase II (deletions in GSTT1 and GSTM1; GSTP1 (c.313A>G); GCLC (TNR(GAG), c.-129C>T); GCLM (c.-588C>T); NAT2 (c.191G>A, c.282C>T, c.341T>C, c.434A>C, c.481C>T, c.590G>A, c.803A>G, c.845A>C, c.857G>A)). Results. Mean patient age was 12.69 ± 6.9 years (5.03–40.36) and did not vary between the RF and RB patients. The male to female ratio was 0.52:0.48 (118:109). Nasal polyposis was diagnosed in 61 patients (26.9%), while 166 children (73.1%) had no nasal polyps. We found that patients with chronic rhinosinusitis and nasal polyps were more likely to have ‘severe’ CFTR genotypes: 95.6% vs 4.4% of patients with a ‘mild’ genotype (р = 0.05). We observed no significant associations between nasal polyposis and analyzed XME gene polymorphisms, as well as glutathione metabolic genes. Conclusion. We found no associations between nasal polyposis and XME gene polymorphisms (phase 1 and 2), which suggests the need for further research aimed to identify other molecular mechanisms underlying the development of nasal polyps in CF patients. Key words: sinonasal polyposis, chronic rhinosinusitis, xenobiotic biotransformation enzymes, cystic fibrosis, glutathione, inflammation

ROLE OF GSTM AND GSTT POLYMORPHIC GENES IN ONCOGENESIS AND THE ONSET OF HEMATOLOGIC NEOPLASMS

Throughout life, a person is exposed to various xenobiotics, one of the biological effects of which is the genotoxic effect, leading to the occurrence of oncogenic mutations. Mutagenic and promutagenic substances can be detoxified with the corresponding xenobiotic biotransformation enzymes, however, if the enzymatic activity of the latter changes, the neutralization of the mutagens occurs at a slower pace. The review discusses the polymorphic genes of enzymes of the second phase of the biotransformation of xenobiotics of the GSTS family and presents modern literature data on the role of GSTM and GSTT in oncogenesis and the development of hemoblastoses. The search of scientific literature was carried out using the PubMed and СyberLeninka databases.

Polymorphisms of xenobiotic biotransformation genes of the glutathione-S-transferase family (GTSS) (review)

Introduction. In modern pulmonology, chronic non-specific lung diseases are considered as multifactorial diseases. They are based on increased sensitivity to environmental factors. A significant role in the manifestation of lung diseases is played by genetic component, in particular, xenobiotic biotransformation enzyme genes of the glutathione-s-transferase family (GSTS). Glutathione-s-transferases (GST) are a family of enzymes involved in detoxification. Genes encoding the proteins GSTA1, GSTM1, GSTP1 and GSTT1 are polymorphic, this can lead to complete or partial loss of enzyme activity and be a predisposing factor for the development of various pathological changes in sensitive people. Aim. A review containing data on the association of the risk of developing lung diseases in carriers of polymorphic genes encoding the second phase enzymes of the xenobiotic detoxification system of the glutathione transferase family to present the current state of the issue, to understand the direction of research and unresolved problems. Materials and methods. There was made an analysis of publications containing the results of a study of the association of the risk of lung diseases in carriers of polymorphisms of xenobiotic biotransformation genes of the GTSS family. Results. The analysis data indicate the association and adverse effect of functionally defective alleles of the genes of the glutathione-s-transferase family (GSTM1 (0), GSTP1 (s) and GSTT1 (0)) on the course of bronchial asthma. The results of studies on the associations of various variants of genetic polymorphism and the development of bronchial asthma are associated with the differential sensitivity of people to various environmental factors, the presence of ethnic differences, combinations of functionally defective variants of several genes. Conclusion. Evaluation of the role of polymorphisms of xenobiotics biotransformation genes in the study of phenotypes of lung disease in children helps to improve and optimize diagnostic and therapeutic measures.

Gene Polymorphism of Xenobiotic Biotransformation Enzymes in Patients with Classical Ph-Negative Myeloproliferative Neoplasms.

The correlation of gene polymorphisms rs4025935 (large deletion), rs1695 (313A>G), rs71748309 (large deletion), and rs1800566 (609C>T) of GSTM1, GSTT1, and NQO1 genes encoding glutathione-S-transferases (GST) M1, P1, and T1 and NADPH-quinone oxidoreductase with the risk of development of classical Ph-negative myeloproliferative neoplasms (polycythemia vera, essential thrombocythemia, and primary myelofibrosis) was studied in the Caucasian ethnicity population of Vyatka region of the Russian Federation. It was found that NQO1*609T allele, NQO1*609T genotypes, and homozygous carriage of a deletion (null) allele of GSTT1 gene are associated with the risk of development of myeloproliferative neoplasms (OR=1.29, 95%CI=1.02-1.64, p=0.04; OR=1.39, 95%CI=1.04-1.85, p=0.03; and OR=1.48, 95%CI=1.03-2.12, p=0.03, respectively). However, no influence of GSTM1 and GSTP1 gene polymorphisms on the risk of development of myeloproliferative disorders was registered.

Oleanolic Acid Alters Multiple Cell Signaling Pathways: Implication in Cancer Prevention and Therapy.

Nowadays, much attention has been paid to diet and dietary supplements as a cost-effective therapeutic strategy for prevention and treatment of a myriad of chronic and degenerative diseases. Rapidly accumulating scientific evidence achieved through high-throughput technologies has greatly expanded the understanding about the multifaceted nature of cancer. Increasingly, it is being realized that deregulation of spatio-temporally controlled intracellular signaling cascades plays a contributory role in the onset and progression of cancer. Therefore, targeting regulators of oncogenic signaling cascades is essential to prevent and treat cancer. A plethora of preclinical and epidemiological evidences showed promising role of phytochemicals against several types of cancer. Oleanolic acid, a common pentacyclic triterpenoid, is mainly found in olive oil, as well as several plant species. It is a potent inhibitor of cellular inflammatory process and a well-known inducer of phase 2 xenobiotic biotransformation enzymes. Main molecular mechanisms underlying anticancer effects of oleanolic acid are mediated by caspases, 5′ adenosine monophosphate-activated protein kinase, extracellular signal–regulated kinase 1/2, matrix metalloproteinases, pro-apoptotic Bax and bid, phosphatidylinositide 3-kinase/Akt1/mechanistic target of rapamycin, reactive oxygen species/apoptosis signal-regulating kinase 1/p38 mitogen-activated protein kinase, nuclear factor-κB, cluster of differentiation 1, CKD4, s6k, signal transducer and activator of transcription 3, as well as aforementioned signaling pathways . In this work, we critically review the scientific literature on the molecular targets of oleanolic acid implicated in the prevention and treatment of several types of cancer. We also discuss chemical aspects, natural sources, bioavailability, and safety of this bioactive phytochemical.

Benzo(a)pyrene Metabolism and EROD and GST Biotransformation Activity in the Liver of Red- and White-Blooded Antarctic Fish.

Climate change and anthropogenic pollution are of increasing concern in remote areas such as Antarctica. The evolutionary adaptation of Antarctic notothenioid fish to the cold and stable Southern Ocean led to a low plasticity of their physiological functions, what may limit their capacity to deal with altered temperature regimes and pollution in the Antarctic environment. Using a biochemical approach, we aimed to assess the hepatic biotransformation capacities of Antarctic fish species by determining (i) the activities of ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase (GST), and (ii) the metabolic clearance of benzo(a)pyrene by hepatic S9 supernatants. In addition, we determined the thermal sensitivity of the xenobiotic biotransformation enzymes. We investigated the xenobiotic metabolism of the red-blooded Gobionotothen gibberifrons and Notothenia rossii, the hemoglobin-less Chaenocephalus aceratus and Champsocephalus gunnari, and the rainbow trout Oncorhynchus mykiss as a reference. Our results revealed similar metabolic enzyme activities and metabolic clearance rates between red- and white-blooded Antarctic fish, but significantly lower rates in comparison to rainbow trout. Therefore, bioaccumulation factors for metabolizable lipophilic contaminants may be higher in Antarctic than in temperate fish. Likewise, the thermal adaptive capacities and flexibilities of the EROD and GST activities in Antarctic fish were significantly lower than in rainbow trout. As a consequence, increasing water temperatures in the Southern Ocean will additionally compromise the already low detoxification capacities of Antarctic fish.

Ovarian xenobiotic biotransformation enzymes are altered during phosphoramide mustard-induced ovotoxicity.

The anti-neoplastic prodrug, cyclophosphamide, requires biotransformation to phosphoramide mustard (PM), which partitions to volatile chloroethylaziridine (CEZ). PM and CEZ are ovotoxicants, however their ovarian biotransformation remains ill-defined. This study investigated PM and CEZ metabolism mechanisms through the utilization of cultured postnatal day 4 (PND4) Fisher 344 (F344) rat ovaries exposed to vehicle control (1% dimethyl sulfoxide (DMSO)) or PM (60μM) for 2 or 4 days. Quantification of mRNA levels via an RT(2) profiler PCR array and target-specific RT-PCR along with Western blotting found increased mRNA and protein levels of xenobiotic metabolism genes including microsomal epoxide hydrolase (Ephx1) and glutathione S-transferase isoform pi (Gstp). PND4 ovaries were treated with 1% DMSO, PM (60μM), cyclohexene oxide to inhibit EPHX1 (CHO; 2mM), or PM + CHO for 4 days. Lack of functional EPHX1 increased PM-induced ovotoxicity, suggesting a detoxification role for EPHX1. PND4 ovaries were also treated with 1% DMSO, PM (60μM), BSO (Glutathione (GSH) depletion; 100μM), GEE (GSH supplementation; 2.5mM), PM ± BSO, or PM ± GEE for 4 days. GSH supplementation prevented PM-induced follicle loss, whereas no impact of GSH depletion was observed. Lastly, the effect of ovarian GSH on CEZ liberation and ovotoxicity was evaluated. Both untreated and GEE-treated PND4 ovaries were plated adjacent to ovaries receiving PM + GEE or PM + BSO treatments. Less CEZ-induced ovotoxicity was observed with both GEE and BSO treatments indicating reduced CEZ liberation from PM. Collectively, this study supports ovarian biotransformation of PM, thereby influencing the ovotoxicity that ensues.

Impact of Obesity on Ovotoxicity Induced by 7,12-dimethylbenz[a]anthracene in Mice1

Insulin, elevated during obesity, regulates xenobiotic biotransformation enzymes, potentially through phosphatidylinositol 3-kinase (PI3K) signaling, in extraovarian tissues. PI3K regulates oocyte viability, follicular activation, and ovarian chemical biotransformation. 7,12-Dimethylbenz[a]anthracene (DMBA), a carcinogen and ovotoxicant, destroys all stages of follicles, leading to premature ovarian failure. Obesity has been reported to promote DMBA-induced tumors, but it remains unknown whether obesity affects ovarian xenobiotic metabolism. Therefore, we investigated ovarian expression of xenobiotic metabolism genes-microsomal epoxide hydrolase (Ephx1), glutathione S-transferase (GST) class Pi (Gstp1) and class mu 1 (Gstm1), and PI3K-signaling members (protein kinase B [AKT] alpha [Akt1], beta [Akt2], and the forkhead transcription factor subfamily 3 [Foxo3])-in lean and obese female mice after DMBA exposure (1 mg/kg; intraperitoneal injection for 14 days). Relative to lean, obese mice had decreased (P < 0.05) healthy primordial and primary follicle numbers but increased (P < 0.05) secondary and preovulatory follicles numbers. Obesity increased (P < 0.05) Akt1, Akt2, Gstm1, and Ephx1 mRNA and pAKT(Ser473/Thr308), GSTM1, GSTP1, and EPHX1 protein levels. DMBA decreased (P < 0.05) ovarian weight in lean and obese mice, however, obese DMBA-treated females had a greater reduction (P < 0.05) in ovarian weight. In both lean and obese mice, DMBA decreased (P < 0.05) all stages of healthy follicle numbers, increased Gstp1 and Ephx1 mRNA as well as GSTM1, GSTP1, and EPHX1 protein levels, and decreased Akt1 and Akt2 mRNA as well as pAKT(Ser473) or pAKT(Thr308), FOXO3, and pFOXO3(Ser253) protein expression. There was an additive effect between obesity and DMBA exposure for increased Gstm1 and Ephx1 mRNA as well as GSTM1 and EPHX1 protein expression.

Frequency of NAT2 and GSTP1 polymorphisms in the Kazakh population.

IntroductionPhase II xenobiotic biotransformation enzymes perform detoxification of hydrophilic and often toxic Phase I products through glutathionetransferase (GST), UDP-glucuronosyltransferase (UDF), N-acetyltransferase (NAT) families and other enzymes. GST protein families metabolize a large number of electrophilic xenobiotics, by conjugating fusing them with glutathione. Arylamine-N-acetyltransferase (NAT) catalyzes the acetylation of the aromatic and heterocyclic amines.Materials and methodsThis study assesses the frequency of NAT2 and GSTP1 gene polymorphisms in 326 healthy individuals from different regions of Kazakhstan by using Real-Time PCR and direct sequencing methods.ResultsThe allele frequencies were calculated for NAT2*5 (0.54) and GSTP1 (0.27). GSTP1 alleles were in the Hardy–Weinberg equilibrium (p > 0.05), while NAT2*5 (p = 0.00) were not. The population differences between North, Northeast and South Kazakhstan regions were also analyzed. No statistically significant differences in the frequency of genotypes were found.ConclusionAllelic polymorphisms of NAT2*5 and GSTP1 genes greatly varied indifferent populations. The Kazakh population was significantly different from the Asian, Caucasoid, African-American and Hispanic populations by NAT2*5 and GSTP1 genes. Allelic variants of the NAT2*5 had a low frequency in Asian populations. Allelic frequency in other world populations varied from 30 to 50%. The differences between Kazakh (0.54) and the world population were statistically significant (p < 0.05). The frequency of GSTP1 (rs1695) in the African American population was 42%. The frequency of GSTP1 in Asian populations varied from 11% to 23%. The frequency in Caucasoid populations was around 30%. The differences between Kazakh population (0.27) and other populations selected were statistically significant (p < 0.05).The study of mutations in GSTP1 and NAT2 genes is necessary in assessing the risk of the development of various diseases, such as cancer. Information on allelic polymorphisms might also be useful for personal perscriptions such as cyclophosphamide, cisplatin, methotrexate, isoniazid, pyrazinamide, and rifampin.

Short-term variability of multiple biomarker response in fish from estuaries: Influence of environmental dynamics

Short-term variability in biomarker responses and the effects of temperature and salinity variation were explored in three fish species ( Dicentrarchus labrax, Solea senegalensis and Pomatoschistus microps) occurring in the Tejo estuary. Short-term variability in biomarkers was observed in all species although no pattern was discerned over time (days to weeks). Antioxidant enzymes activity (superoxide dismutase (SOD) and catalase (CAT)) showed low temporal variability, indicating some constancy or baseline level in antioxidant responses. Only CAT activity in S. senegalensis was correlated with temperature, suggesting that exposure to contaminants triggered antioxidant acclimation. Higher short-term variability was observed in xenobiotic biotransformation enzymes activity (phase I ethoxyresorufin O-deethylase (EROD) and phase II glutathione S-transferase (GST)). Yet a significant correlation between EROD and GST in D. labrax and S. senegalensis suggests a concomitant response to contaminants. Moreover the lack of correlation between xenobiotic biotransformation enzymes and abiotic variables on concordant time scales, suggest a high specificity of these biomarkers to chemical exposure, rather than high variability due to environmental dynamics.