GSTM1 Modulates Expression of Endothelial Adhesion Molecules in Uremic Milieu

Deletion polymorphism of glutathione S-transferase M1 (GSTM1), a phase II detoxification and antioxidant enzyme, increases susceptibility to end-stage renal disease (ESRD) as well as the development of cardiovascular diseases (CVD) among ESRD patients and leads to their shorter cardiovascular survival. The mechanisms by which GSTM1 downregulation contributes to oxidative stress and inflammation in endothelial cells in uremic conditions have not been investigated so far. Therefore, the aim of the present study was to elucidate the effects of GSTM1 knockdown on oxidative stress and expression of a panel of inflammatory markers in human umbilical vein endothelial cells (HUVECs) exposed to uremic serum. Additionally, we aimed to discern whether GSTM1-null genotype is associated with serum levels of adhesion molecules in ESRD patients. HUVECs treated with uremic serum exhibited impaired redox balance characterized by enhanced lipid peroxidation and decreased antioxidant enzyme activities, independently of the GSTM1 knockdown. In response to uremic injury, HUVECs exhibited alteration in the expression of a series of inflammatory cytokines including retinol-binding protein 4 (RBP4), regulated on activation, normal T cell expressed and secreted (RANTES), C-reactive protein (CRP), angiogenin, dickkopf-1 (Dkk-1), and platelet factor 4 (PF4). GSTM1 knockdown in HUVECs showed upregulation of monocyte chemoattractant protein-1 (MCP-1), a cytokine involved in the regulation of monocyte migration and adhesion. These cells also have shown upregulated intracellular and vascular cell adhesion molecules (ICAM-1 and VCAM-1). In accordance with these findings, the levels of serum ICAM-1 and VCAM-1 (sICAM-1 and sVCAM-1) were increased in ESRD patients lacking GSTM1, in comparison with patients with the GSTM1-active genotype. Based on these results, it may be concluded that incubation of endothelial cells in uremic serum induces redox imbalance accompanied with altered expression of a series of cytokines involved in arteriosclerosis and atherosclerosis. The association of GSTM1 downregulation with the altered expression of adhesion molecules might be at least partly responsible for the increased susceptibility of ESRD patients to CVD

Is Increased Susceptibility to Balkan Endemic Nephropathy in Carriers of Common GSTA1 (*A/*B) Polymorphism Linked with the Catalytic Role of GSTA1 in Ochratoxin A Biotransformation? Serbian Case Control Study and In Silico Analysis

Although recent data suggest aristolochic acid as a putative cause of Balkan endemic nephropathy (BEN), evidence also exists in favor of ochratoxin A (OTA) exposure as risk factor for the disease. The potential role of xenobiotic metabolizing enzymes, such as the glutathione transferases (GSTs), in OTA biotransformation is based on OTA glutathione adducts (OTHQ-SG and OTB-SG) in blood and urine of BEN patients. We aimed to analyze the association between common GSTA1, GSTM1, GSTT1, and GSTP1 polymorphisms and BEN susceptibility, and thereafter performed an in silico simulation of particular GST enzymes potentially involved in OTA transformations. GSTA1, GSTM1, GSTT1 and GSTP1 genotypes were determined in 207 BEN patients and 138 non-BEN healthy individuals from endemic regions by polymerase chain reaction (PCR). Molecular modeling in silico was performed for GSTA1 protein. Among the GST polymorphisms tested, only GSTA1 was significantly associated with a higher risk of BEN. Namely, carriers of the GSTA1*B gene variant, associated with lower transcriptional activation, were at a 1.6-fold higher BEN risk than those carrying the homozygous GSTA1*A/*A genotype (OR = 1.6; p = 0.037). In in silico modeling, we found four structures, two OTB-SG and two OTHQ-SG, bound in a GSTA1 monomer. We found that GSTA1 polymorphism was associated with increased risk of BEN, and suggested, according to the in silico simulation, that GSTA1-1 might be involved in catalyzing the formation of OTHQ-SG and OTB-SG conjugates

BMP axis in cancer cachexia

BACKGROUND Cancer cachexia is a devastating metabolic syndrome characterized by systemic inflammation and massive muscle and adipose tissue wasting. Although cancer cachexia is responsible for about 25% of cancer deaths, no effective therapies are available, and the underlying mechanisms have not been fully elucidated. Its occurrence complicates patients’ management, reduces tolerance to treatments and negatively affects patient quality of life. Muscle wasting, mainly due to increased protein breakdown rates, is one of the most prominent features of cachexia. Blocking muscle loss in cachexia mouse models dramatically prolongs survival even of animals in which tumor growth is not inhibited. Recent observations showed that bone morphogenetic protein (BMP) signaling, acting through Smad1, Smad5 and Smad8 (Smad1/5/8), is a master regulator of muscle homeostasis. BMP-Smad1/5/8 axis negatively regulates a novel ubiquitin ligase (MUSA1) required for muscle loss induced by denervation. MATERIALS AND METHODS First aim of the present work was to test if alterations of the BMP signaling pathway occur in cancer-induced muscle wasting in patients. For this purpose we checked the state of activation of the BMP pathway in muscle of cachectic vs non–cachectic patients affected by colon, pancreatic and esophagus cancer and in control subjects. We checked by Western Blot the phosphorylation levels of Smad1/5/8 and of Smad3 and by quantitative Real-Time PCR (qRT-PCR) the expression levels of different atrophy-related genes The second aim was to evaluate the degree of muscle atrophy and distribution of muscle fibers in patients and control subjects using morphometric and immunohistochemical analyses. We also performed analysis on distribution of NCAM positive muscle fibers to assess the effect of denervation on muscle tropism. RESULTS From December 2014 we collected 95 rectus abdominis muscle biopsies of cancer patients and 11 from control subjects. In line with the results we obtained in C26 mice model (a well-established cancer cachexia experimental model) Smad1/5/8 phosphorylation, readout of the state of activation of the BMP pathway, was nearly completely abrogated in the muscles of cancer cachectic patients compared to cancer non-cachectic ones. Interestingly, the level of phosphorylation of Smad3 was not significantly affected suggesting specific effects of cancer growth on BMP pathway. The expression levels of different atrophy-related genes including MUSA1 were induced in the cachectic muscles. Interestingly, several BMP related genes are also changing the expression during cancer growth. We also found a correlation between suppression of BMP pathway, expression of atrophy related genes and Noggin, known to block BMP pathway. Morphometric analysis shown that patients with cancer cachexia have smaller myofiber diameter (in particular fast type fibers) in comparison to age-matched controls. In skeletal muscle from cancer patients (either cachectic or non-cachectic) we detected a prevalence of flat shaped, angulated and severely atrophic myofibers (i.e. morphological features of denervated myofibers), big fiber-type grouping (i.e. typical hallmark of denervation/reinnervation events) and numerous NCAM positive myofibers (i.e. specific marker of denervation). CONCLUSIONS These findings are consistent with the hypothesis that BMP inhibition is permissive to cachexia onset. Since the reactivation of the BMP-dependent signaling and MUSA1 suppression was sufficient to prevent tumor-induced muscle atrophy in our C26 mouse model (data not shown), the present data suggest that the BMP axis can be an effective target for therapeutic approaches to counteract cachexia also in cancer patients. The results of morphometric and immunohistochemical studies collected till now may suggest that denervation contributes to myofiber atrophy in cancer cachexia

Association of Nrf2, SOD2 and GPX1 polymorphisms with biomarkers of oxidative distress and survival in end-stage renal disease patients

© 2019 by the authors. The oxidative stress response via Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) interlinks inflammation- and metabolism-related pathways in chronic kidney disease. We assessed the association between polymorphisms in Nrf2, superoxide dismutase (SOD2), glutathione peroxidase (GPX1), and the risk of end-stage renal disease (ESRD). The modifying effect of these polymorphisms on both oxidative phenotype and ESRD prognosis, both independently and/or in combination with the glutathione S-transferase M1 (GSTM1) deletion polymorphism, was further analyzed. Polymorphisms in Nrf2 (rs6721961), SOD2 (rs4880), GPX1 (rs1050450), and GSTM1 were determined by PCR in 256 ESRD patients undergoing hemodialysis and 374 controls. Byproducts of oxidative stress were analyzed spectrophotometically or by ELISA. Time-to-event modeling was performed to evaluate overall survival and cardiovascular survival. The SOD2 Val/Val genotype increased ESRD risk (OR = 2.01, p = 0.002), which was even higher in combination with the GPX1 Leu/Leu genotype (OR = 3.27, p = 0.019). Polymorphism in SOD2 also showed an effect on oxidative phenotypes. Overall survival in ESRD patients was dependent on a combination of the Nrf2 (C/C) and GPX1 (Leu/Leu) genotypes in addition to a patients’ age and GSTM1 polymorphism. Similarly, the GPX1 (Leu/Leu) genotype contributed to longer cardiovascular survival. Conclusions: Our results show that SOD2, GPX1, and Nrf2 polymorphisms are associated with ESRD development and can predict survival

Association of SOD2 (Rs4880) and GPX1 (rs1050450) gene polymorphisms with risk of Balkan endemic nephropathy and its related tumors

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. T. Background: Experimental data show that superoxide dismutase 2 (SOD2) is involved in ochratoxin (OTA)-induced nephrotoxicity, whereas clinical data indicate the role of SOD2 rs4880 or glutathione peroxidase 1 (GPX1) rs1050450 polymorphisms in end-stage renal disease and urothelial carcinoma risk, known to be the major complications of Balkan endemic nephropathy (BEN). Therefore, we hypothesized that SOD2 and GPX1 gene polymorphisms would influence the risk of BEN and its associated tumors. Materials and Methods: The study was conducted in 207 BEN patients and 86 controls from endemic areas. Results: Individuals with both copies of variant SOD2 allele, known for lower mitochondrial antioxidant protection, are at a significantly higher BEN risk (OR = 2.6, p = 0.021). No association was observed between GPX1 gene polymorphism and BEN risk. Combining SOD2 and GPX1 genotypes did not alter the risk of BEN development. Regarding the risk of urothelial tumors in BEN patients, none of the polymorphisms studied was significantly associated with the risk of these tumors. Conclusions: Polymorphism in SOD2 rs4880 gene affects the risk of BEN development. Hence, SOD2 genotyping could, together with a panel of other enzymes, be used as a biomarker of susceptibility in BEN areas

Does occupational exposure to solvents and pesticides in association with glutathione S-transferase A1, M1, P1, and T1 polymorphisms increase the risk of bladder cancer? The Belgrade case-control study.

OBJECTIVE: We investigated the role of the glutathione S-transferase A1, M1, P1 and T1 gene polymorphisms and potential effect modification by occupational exposure to different chemicals in Serbian bladder cancer male patients. PATIENTS AND METHODS: A hospital-based case-control study of bladder cancer in men comprised 143 histologically confirmed cases and 114 age-matched male controls. Deletion polymorphism of glutathione S-transferase M1 and T1 was identified by polymerase chain reaction method. Single nucleotide polymorphism of glutathione S-transferase A1 and P1 was identified by restriction fragment length polymorphism method. As a measure of effect size, odds ratio (OR) with corresponding 95% confidence interval (95%CI) was calculated. RESULTS: The glutathione S-transferase A1, T1 and P1 genotypes did not contribute independently toward the risk of bladder cancer, while the glutathione S-transferase M1-null genotype was overrepresented among cases (OR = 2.1, 95% CI = 1.1-4.2, p = 0.032). The most pronounced effect regarding occupational exposure to solvents and glutathione S-transferase genotype on bladder cancer risk was observed for the low activity glutathione S-transferase A1 genotype (OR = 9.2, 95% CI = 2.4-34.7, p = 0.001). The glutathione S-transferase M1-null genotype also enhanced the risk of bladder cancer among subjects exposed to solvents (OR = 6,5, 95% CI = 2.1-19.7, p = 0.001). The risk of bladder cancer development was 5.3-fold elevated among glutathione S-transferase T1-active patients exposed to solvents in comparison with glutathione S-transferase T1-active unexposed patients (95% CI = 1.9-15.1, p = 0.002). Moreover, men with glutathione S-transferase T1-active genotype exposed to pesticides exhibited 4.5 times higher risk in comparison with unexposed glutathione S-transferase T1-active subjects (95% CI = 0.9-22.5, p = 0.067). CONCLUSION: Null or low-activity genotypes of the glutathione S-transferase A1, T1, and P1 did not contribute independently towards the risk of bladder cancer in males. However, in association with occupational exposure, low activity glutathione S-transferase A1 and glutathione S-transferase M1-null as well as glutathione S-transferase T1-active genotypes increase individual susceptibility to bladder cancer

Markers of Oxidative Stress and Endothelial Dysfunction Predict Haemodialysis Patients Survival

© 2019 © 2019 S. Karger AG, Basel. Copyright: All rights reserved. Introduction: Overall survival of patients with end-stage renal disease (ESRD) remains poor. Oxidative stress is one of the major risk factors associated with mortality in this patient group. As glutathione S-transferases (GST) are well-established antioxidants, we hypothesized that a model including GST gene polymorphisms, oxidative damage byproducts and cell adhesion markers has a prognostic role in ESRD patient survival. Methods: A prospective study of 199 patients with ESRD on haemodialysis was conducted. GST genotype, oxidative stress byproducts and cell adhesion molecules were measured in plasma. Multivariate Cox regression and Kaplan-Meier survival analyses were performed to test the predictive ability of these parameters in the 8-year follow-up period. Results: GSTM1-null genotype was associated with significantly shorter overall (HR 1.6, p = 0.018) and cardiovascular-specific (HR 2.1, p = 0.010) survival. Oxidative stress byproducts (advanced oxidation protein products [AOPP], prooxidant-antioxidant balance [PAB], malondialdehyde [MDA]) and cell adhesion molecules (soluble vascular cell adhesion molecule-1 [sVCAM-1] and soluble intercellular adhesion molecule-1 [sICAM-1]) demonstrated a significant predictive role in terms of overall and cardiovascular survival. When 6 biomarkers (GSTM1 genotype, high AOPP/PAB/MDA/-sVCAM-1/sICAM-1) were combined into a scoring model, a significantly shorter overall and cardiovascular survival was observed for patients with the highest score (p < 0.001). Conclusion: We identified a novel panel of biomarkers that can be utilized in predicting survival in ESRD patients. This biomarker signature could enable better monitoring of patients and stratification into appropriate treatment groups

Glutathione S-transferase T1, O1 and O2 polymorphisms are associated with survival in muscle invasive bladder cancer patients.

OBJECTIVE: To examine the association of six glutathione transferase (GST) gene polymorphisms (GSTT1, GSTP1/rs1695, GSTO1/rs4925, GSTO2/rs156697, GSTM1, GSTA1/rs3957357) with the survival of patients with muscle invasive bladder cancer and the genotype modifying effect on chemotherapy. PATIENTS AND METHODS: A total of 105 patients with muscle invasive bladder cancer were included in the study. The follow-up lasted 5 years. The effect of GSTs polymorphisms on predicting mortality was analyzed by the Cox proportional hazard models, while Kaplan-Meier analysis was performed to assess differences in survival. RESULTS: GSTT1 active, GSTO1 Asp140Asp or GSTO2 Asp142Asp genotypes were independent predictors of a higher risk of death among bladder cancer patients (HR = 2.5, P = 0.028; HR = 2.9, P = 0.022; HR = 3.9, P = 0.001; respectively) and significantly influenced the overall survival. There was no association between GSTP1, GSTM1 and GSTA1 gene variants with overall mortality. Only GSTO2 polymorphism showed a significant effect on the survival in the subgroup of patients who received chemotherapy (P = 0.006). CONCLUSION: GSTT1 active genotype and GSTO1 Asp140Asp and GSTO2 Asp142Asp genotypes may have a prognostic/pharmacogenomic role in patients with muscle invasive bladder cancer