Glutathione S-transferase Alpha Research Articles

Investigation of Clozapine and Olanzapine Reactive Metabolite Formation and Protein Binding by Liquid Chromatography-Tandem Mass Spectrometry.

Drug-induced toxicity has, in many cases, been linked to oxidative metabolism resulting in the formation of reactive metabolites and subsequent covalent binding to biomolecules. Two structurally related antipsychotic drugs, clozapine (CLZ) and olanzapine (OLZ), are known to form similar nitrenium ion reactive metabolites. CLZ-derived reactive metabolites have been linked to agranulocytosis and hepatotoxicity. We have studied the oxidative metabolism of CLZ and OLZ as well as two known metabolites of CLZ, desmethyl-CLZ (DCLZ), and CLZ-N-oxide (CLZ-NO), using in vitro rat liver microsomal (RLM) incubations with glutathione (GSH) trapping of reactive metabolites and liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS). Reactive metabolite binding to selected standard peptides and recombinant purified human proteins was also evaluated. Bottom-up proteomics was performed using two complementary proteases, prefractionation of peptides followed by LC-HRMS/MS for elucidating modifications of target proteins. Induced RLM was selected to form reactive metabolites enzymatically to assess the complex profile of reactive metabolite structures and their binding potential to standard human proteins. Multiple oxidative metabolites and several different GSH adducts were found for CLZ and OLZ. Modification sites were characterized on human glutathione S-transferase (hGST) alpha 1 (OLZ-modified at Cys112), hGST mu 2 (OLZ at Cys115), and hGST pi (CLZ, DCLZ, CLZ-NO and OLZ at Cys170), human microsomal GST 1 (hMGST1, CLZ and OLZ at Cys50), and human serum albumin (hSA, CLZ at Cys34). Furthermore, two modified rat proteins, microsomal GST 1 (CLZ and OLZ at Cys50) and one CYP (OLZ-modified, multiple possible isoforms), from RLM background were also characterized. In addition, direct effects of the reactive metabolite modifications on proteins were observed, including differences in protease cleavage specificity, chromatographic behavior, and charge-state distributions.

Selenoneine Ameliorates Hepatocellular Injury and Hepatic Steatosis in a Mouse Model of NAFLD.

Selenoneine is a novel organic selenium compound markedly found in the blood, muscles, and other tissues of fish. This study aimed to determine whether selenoneine attenuates hepatocellular injury and hepatic steatosis in a mouse model of non-alcoholic fatty liver disease (NAFLD). Mice lacking farnesoid X receptor (FXR) were used as a model for fatty liver disease, because they exhibited hepatomegaly, hepatic steatosis, and hepatic inflammation. Fxr-null mice were fed a 0.3 mg Se/kg selenoneine-containing diet for four months. Significant decreases in the levels of hepatomegaly, hepatic damage-associated diagnostic markers, hepatic triglycerides, and total bile acids were found in Fxr-null mice fed with a selenoneine-rich diet. Hepatic and blood clot total selenium concentrations were 1.7 and 1.9 times higher in the selenoneine group than in the control group. A marked accumulation of selenoneine was found in the liver and blood clot of the selenoneine group. The expression levels of oxidative stress-related genes (heme oxygenase 1 (Hmox1), glutathione S-transferase alpha 1 (Gsta1), and Gsta2), fatty acid synthetic genes (stearoyl CoA desaturase 1(Scd1) and acetyl-CoA carboxylase 1 (Acc1)), and selenoprotein (glutathione peroxidase 1 (Gpx1) and selenoprotein P (Selenop)) were significantly decreased in the selenoneine group. These results suggest that selenoneine attenuates hepatic steatosis and hepatocellular injury in an NAFLD mouse model.

Regulation of Actg1 and Gsta2 is possible mechanism by which capsaicin alleviates apoptosis in cell model of 6-OHDA-induced Parkinson's disease.

The present study aimed to identify the gene expression changes conferred by capsaicin in the cell model of 6-OHDA-induced Parkinson's disease, to disclose the molecular mechanism of action of capsaicin. We used capsaicin-treated and paraffin-embedded wax blocks containing substantia nigra tissue from 6-OHDA-induced Parkinson's disease rats to analyze transcriptional changes using Affymetrix GeneChip Whole Transcript Expression Arrays. A total of 108 genes were differentially expressed in response to capsaicin treatment, and seven of these genes were selected for further analysis: Olr724, COX1, Gsta2, Rab5a, Potef, Actg1, and Acadsb, of which Actg1 (actin gamma 1) was down-regulated and Gsta2 (Glutathione S-transferase alpha 2) was up-regulated. We successfully overexpressed Actg1 and Gsta2 in vitro. CCK-8 detection and flow cytometry demonstrated that overexpression of Actg1 and Gsta2 increased apoptosis in the 6-OHDA-induced Parkinson's disease cell model. The imbalance between Actg1 and Gsta2 may be one of the mechanisms of cell damage in Parkinson's disease (PD). Capsaicin can protect the cells and reduce the apoptosis rate by regulating Actg1 and Gsta2.

Expressions of glutathione S-transferase alpha, mu, pi, and theta in the skin samples of patients with acne rosacea.

Data point to the importance of oxidative stress in rosacea. Glutathione S-transferases (GSTs) have substantial roles in a wide variety of oxidative stress-related conditions. To evaluate the immunohistochemical staining characteristics of GST alpha (GSTA), mu (GSTM), pi (GSTP), and theta (GSTT) in patients with rosacea. The study included 23 women and 7 men with rosacea (mean±SD age 49±11year) and 15 healthy control subjects (10 women, 5 men; mean±SD age 47.86±10.88year). For each patient, the average disease duration, disease subtype, ocular involvement, and severity score were recorded. A 3-mm punch biopsy was taken from the facial skin of each patient and control. Expression of GST isoenzymes was analyzed immunohistochemically. Expressions of GSTM1, GSTP1, and GSTT1 were significantly elevated in patients with rosacea compared to those in the control group (P=.0001, P=.0002, P<.0001, respectively). In the rosacea group, GSTT1 expression was significantly stronger than GSTP1 and GSTA1 expressions (P=.019, P<.0001, respectively). There were no significant associations between expressions of GST isoenzymes and gender, age, average duration of illness, disease subtype, ocular involvement, or severity score in the patient group (all P>.05). In rosacea, the significant increase of GSTT1, GSTP1, and GSTM1 expressions might result from activation of GST as an outcome of extreme free radical generation from triggered neutrophils or ultraviolet vulnerability. These findings support the relevance of oxidant stress in the pathogenesis of rosacea.

A Method for the Evaluation of Site-Specific Nephrotoxic Injury in the Intact Rat Kidney.

In a previously published report we detailed an in situ method to quantify cell death in the renal cortex by perfusing the cell membrane impermeable fluorochrome, ethidium homodimer in situ. The objective of the present study was to use this in situ viability assay to examine cell death following the administration of nephrotoxic drugs known to produce cell death and/or injury in specific segments of the nephron. Male Sprague/Dawley rats were treated with the following nephrotoxicants: Gentamicin, amphotericin-B, and indomethacin. Results of the in situ viability assay indicated that gentamicin and amphotericin-B treatment caused cell death localized in the kidney cortex and medulla, respectively. The urinary biomarker kidney injury molecule—1 (Kim-1) showed significant increases in both gentamicin (20 fold increase) and amphotericin-B-treated (9.2 fold increase) animals. Urinary alpha glutathione-S-transferase (GST) showed significant increases for gentamicin (6.2 fold increase) only and mu GST for amphotericin-B-treated (19.1 fold increase) animals only. These results show that this in situ viability assay provides a sensitive method to identify cell death in different regions of the kidney. Furthermore, urinary alpha GST and mu GST are specific for proximal and distal tubule injury, respectively; urinary Kim-1 demonstrated greater sensitivity to both proximal and distal tubule injury.

Alpine and lowland grazing differentially alter the reproductive tract redox milieu and amino acid composition in cattle

An alpine environment is unique due to pasture biodiversity, with an abundant content of natural antioxidant polyphenols. The present study investigated the effects of lowland and alpine grazing on the oviduct and uterine tissue redox status and amino acid concentrations in plasma and reproductive fluids. In the first experiment, heifers grazed on lowland (H-LOW: n = 13) and on alpine (H-ALP: n = 15) pastures. In the second experiment, heifers grazed on the same lowland (HS-LOW: n = 6) and on a different alpine (HS-ALP: n = 6) pasture. The abundance of mRNA transcripts for antioxidant enzymes in the oviduct (glutathione S-transferase alpha 2, glutathione synthetase (GSS)) and the endometrium (catalase, glutathione-disulfide reductase, GSS) was less (P < 0.05), and for glutathione peroxidase 4 in the endometrium greater (P = 0.006) in the H-LOW than in the H-ALP group. The abundance of mRNA transcript for catalase was less in the endometrium in the H-LOW than in the H-ALP (P = 0.001) group. Catalase and NAD(P)H quinone dehydrogenase 1 concentrations in the oviduct were greater in the HS-LOW than in the HS-ALP group (P < 0.05). Of 32 amino acids analysed, there were differences in concentrations in the H-LOW and H-ALP group of 13, seven and 15 in plasma, oviduct and uterine fluids, respectively (P < 0.05). Comparing the HS-LOW to the HS-ALP groups, there were 13, one and three amino acids in the plasma, oviduct and uterine fluids, respectively, that were differentially abundant (P < 0.05). The grazing systems had some effect on the redox status and amino acid patterns in reproductive tissues.

Plasma α-Glutathione S-Transferase Evaluation in Patients with Acute and Chronic Liver Injury.

High concentration of alpha-glutathione S-transferase (α-GST) in the liver and its short half-life make this enzyme clinically useful in assessing hepatocellular damage. We aimed to investigate the significance of α-GST evaluation in monitoring of liver injury in acute and chronic liver diseases. 20 healthy volunteers and 52 patients were included in the study. The patients were divided into three groups: group I (acute viral hepatitis B or C), group II (chronic hepatitis B or C), and group III (chronic liver disease or cirrhosis with different etiologies). The concentration of α-GST and the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured in all examined groups. α-GST, ALT, and AST were statistically higher in all patient groups than in the control group. Statistically higher values of all assessed parameters were observed in group I compared with remaining patients. Statistically higher activities of ALT and AST are observed in group III compared with group II. Significant positive correlations were noted between α-GST and ALT/AST in groups I and III. The results indicate that the assay of α-GST in combination with the other conventional markers may be found as a confirmatory test for hepatocellular damage.

Melatonin ameliorates sodium valproate-induced hepatotoxicity in rats.

Valproic acid (VPA) is a anticonvulsant and mood-stabilizing agent used to treat epilepsy in patients of all ages. However, it can cause hepatotoxicity with increased oxidative stress. Melatonin (MEL) is known as antioxidant and antiinflammatory agent. Therefore, the present study designed to investigate the probable protective role of melatonin against VPA-induced liver toxicity. For that purpose, 28 Wistar rats were randomly selected and divided into four groups, namely the Group C (vehicle), VPA (500mg/kg/day VPA), MEL + VPA (10mg/kg/day melatonin + 500mg/kg/day VPA) and MEL (10mg/kg/day melatonin). The agents were given by oral gavage for 14days. Blood and liver tissue samples from all the rats were harvested on the 15th day of experiment. Biochemical analyses were conducted on the blood samples. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), alpha glutathione S-transferases (α-GST), nuclear factor-κB (NF-κB), myeloperoxidase (MPO) and changes in gene expression were examined in the liver tissues. Also, liver histopathological analyses were conducted. VPA administration significantly increased the levels of α-GST, MDA, NF-κB and of IL-1β, TNF-α gene expression in the liver compared to Group C. Moreover, vacuolization, hydropic degeneration, inflammatory cell infiltration, and sinusoidal congestion were commonly detected in the VPA-treated group along with the highest apoptotic index (TUNEL staining) values. Melatonin administration was revealed to exhibit powerful protective properties at cellular, inflammatory and oxidative level activities against VPA-induced liver toxicity. Therefore, melatonin administration may be used as an adjuvant therapy against to VPA-induced liver toxicity.

Biomarkers for acute mesenteric ischemia diagnosis: state of the art and perspectives

Acute mesenteric ischemia (AMI) is one of the most severe diagnostic and therapeutic vital emergencies. This affection is characterized by the insufficient blood supply to the gastrointestinal tract, related to an occlusive or non-occlusive mechanism, resulting in an ischemic and inflammatory injury that may progress to necrosis of the intestinal wall. The clinical picture is nonspecific, dominated by acute abdominal pain. At present, no early biological marker is commonly used in clinical practice for diagnostic purposes. The purpose of this review was to review the markers that have been evaluated in this condition. Among the biological blood markers which have shown a diagnostic interest in the IMA, there are notably the two stereoisomers of lactate (D and L), D-dimers, and alpha glutathione transferase. More specific markers include the intestinal fatty acid binding protein or I-FABP, which is a marker of enterocyte necrosis, citrulline, a marker of enterocyte mass, or Smooth muscle protein 22 (SM22) marker for muscle damage. The early diagnosis of intestinal ischemia remains a challenge. It is likely that in the future IMA's biomarker research will be better customized and adapted to the physiopathological mechanism. More global approaches (proteomics, metabolomics) should also make it possible to identify new biomarkers.

Diagnostic Biomarkers to Diagnose Acute Allograft Rejection After Liver Transplantation: Systematic Review and Meta-Analysis of Diagnostic Accuracy Studies.

Objective: A systematic review and meta-analysis of diagnostic biomarkers for noninvasive diagnosis of acute allograft rejection following liver transplantation.Background: Noninvasive blood and urine markers have been widely explored in recent decades for diagnosing acute rejection after liver transplantation. However, none have been translated into routine clinical use so far due to uncertain diagnostic accuracy, and liver biopsy remains the gold standard.Methods: Systematic literature searches of Medline, Cochrane and Embase were conducted up to February 2019 to identify studies evaluating the use of noninvasive markers in diagnosing allograft rejection following liver transplantation. Meta-analysis was performed using a random effects model with DerSimonian–Laird weighting and the hierarchical summary receiver operating curve.Results: Of 560 identified studies, 15 studies (1,445 patients) met the inclusion criteria. The following markers were tested: acid labile nitroso-compounds (NOx), serum amyloid A protein, procalcitonin, peripheral blood eosinophil count, peripheral blood T-cell activation and interleukin 2 (IL-2) receptor, guanylate-binding protein-2 mRNA, graft-derived cell-free DNA, pi-glutathione S-transferase, alpha-glutathione S-transferase and serum HLA class I soluble antigens. Only eosinophil count was tested in multiple studies, and they demonstrated high heterogeneity (I2 = 72% [95% CI: 0.5–0.99]). IL-2 receptor demonstrated the highest sensitivity (89% [95% CI: 0.78–0.96]) and specificity (81% [95% CI: 0.69–0.89]).Conclusion: IL-2 receptor expression demonstrated the highest diagnostic accuracy, while the peripheral eosinophil count was the only marker tested in more than one study. Presently, liver biopsy remains superior to noninvasive diagnostic biomarkers as most studies exhibited inferior designs, hindering possible translation into clinical application.

Correlation between hepatic oxidative damage and clinical severity and mitochondrial gene sequencing results in biliary atresia

To assess the level of hepatic oxidative damage and its correlation with clinical severity in biliary atresia (BA), and to understand BA mitochondrial gene sequencing. Forty-eight BA patients and 28 control subjects (20 hepatoblastoma and 8 cholestasis patients) were enrolled. Hepatic oxidative damage was assessed by the expression of oxidation and antioxidant genes, and the correlation between oxidative damage and BA incidence, liver inflammation, and fibrosis was evaluated. Moreover, 8-hydroxyguanine (8-OHdG), mitochondrial DNA (mtDNA) copy number, and mitochondrial gene sequences were determined to evaluate oxidative mtDNA damage in BA. The expression of oxidation gene cytochrome b-245 beta chain (CYBB) in BA was significantly increased and patients with a higher CYBB expression had the higher risk of BA incidence, liver inflammation, and cirrhosis. However, the expression of antioxidant genes was significantly decreased, and glutathione S-transferase alpha 1 (GSTA1) negatively correlated with BA incidence and cirrhosis. When GSTA1 mRNA expression was <0.5487, the sensitivity was 80.85% and the specificity was 80% for BA diagnosis. Moreover, 8-OHdG was increased, whereas mtDNA copy number was significantly decreased in BA. Using mitochondrial gene sequencing, 10 mutation sites were identified, and one family showed a maternal inheritance in genetic loci 15 326. In BA, oxidative damage positively correlated with BA incidence, liver inflammation, and cirrhosis. GSTA1 could be a novel diagnostic indicator. Genetic loci 15 326 could be a maternal genetic mutation site. Taken together, antioxidation therapy after Kasai surgery might have great potential in relieving liver inflammation and fibrosis in BA patients.

A multiplexed UPLC-MS/MS assay for the simultaneous measurement of urinary safety biomarkers of drug-induced kidney injury and phospholipidosis

Drug-induced kidney injury (DIKI) is a major concern in drug risk assessment given its clinical importance and the absence of a sensitive/specific method of diagnosis. Pharmaceutical regulatory agencies have qualified and issued letters of support for new biomarkers to better evaluate DIKI in nonclinical toxicity and clinical studies. Additional efforts have focused on drug-induced phospholipidosis (DIPL) and its potential link with collateral renal damage. The combined use of urinary biomarkers is an efficient way to evaluate renal safety in nonclinical and clinical studies. Eight FDA/EMA/PMDA qualified (or supported) urinary biomarkers, including kidney injury molecule-1 (KIM-1), β2-microglobulin (B2M), clusterin (CLU), cystatin C (CysC), trefoil factor 3 (TFF3), neutrophil gelatinase-associated lipocalin (NGAL), osteopontin (OPN), and alpha-glutathione S-transferase (α-GST), were quantified by multiplex UPLC-MS/MS in a repeat dose study of gentamicin in rats. Rats administered gentamicin at 100 mg/kg/day for 2 weeks developed renal lesions detected by histopathology. Biomarkers of tubular damage (CLU, KIM-1, OPN) increased 9.8, 34.7, and 35.6-fold (relative to concurrent controls), respectively, after 2 weeks of dosing. Biomarkers of glomerular damage and/or impairment of tubular reabsorption (CysC, B2M) increased 11.7 and 22.6-fold. NGAL and α-GST increased <3-fold after 2 weeks of dosing. TFF3 was comparable to concurrent controls. The elevated biomarker concentrations met PSTC threshold criteria and were consistent with mechanisms of gentamicin nephrotoxicity. Increased urinary di-22:6-BMP indicated concomitant DIPL as confirmed by TEM. This work provides evidence supporting the combined use of the DIKI biomarker panel and di-22:6-BMP as a biomarker of DIPL in drug risk assessment.

Proteomic identification of an alpha class glutathione S-transferase in freshwater snails (Bulinus globosus)

Abstract Bulinus globosus is a freshwater snail that serves as intermediate host for Schistosoma haematobium and is known to be drought-tolerant. A previous report on the alteration in the status of glutathione S-transferase (GST) in B. globosus during aestivation and recovery, suggested that GST might be involved in the adaptation of the organism to drought. Therefore, the present study aims to characterize GST isoforms that are displayed in snails under drought stress, sampled during the dry season, and those under recovery, sampled during the rainy season. Our data show that the hepatopancreas contained the highest level of GST compared to foot muscle, hemolymph, and visceral mass. GST activity in the hepatopancreas of snails under drought stress was about 2-3 times higher than that of the recovered snails. Activity staining of a polyacrylamide gel revealed that B. globosus both in the active and inactive state has at least three forms of GST. Based on SDS-PAGE, the multiplicity of the main GSTs in the hepatopancreas of B. globosus (BgGSTs) was further revealed by the presence of five protein bands. In addition, LC-MS/MS analysis of BgGST 2, 3 and 4 revealed the expression of alpha GST. In conclusion, B. globosus exhibits tissue-specific expression of multiple GSTs with elevated activities when the organism is under stress. Elevated activities coupled with an alpha GST class expression accentuate the role of BgGSTs as an antioxidant defense system, in particular under stress conditions.

A Performance Evaluation of Liver and Skeletal Muscle-Specific miRNAs in Rat Plasma to Detect Drug-Induced Injury.

Liver and skeletal muscle-specific microRNAs (miRNAs) are currently being evaluated as novel plasma biomarkers that may out-perform or add value to the conventional liver injury biomarkers alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and to the skeletal muscle injury biomarkers AST and creatine kinase (CK). A comprehensive evaluation was conducted to assess the relative performance of these miRNAs to detect and distinguish liver from muscle tissue injury. The performance of miR-122 and miR-192 for liver and miR-1, miR-133a, miR-133b, and miR-206 for skeletal muscle was compared with 10 enzymatic or protein biomarkers across 27 compounds causing specific types of tissue injury in rat. Receiver operator characteristic analyses were performed comparing the relative sensitivity and specificity of each of the biomarkers in individual animals with histopathology observations of necrosis and/or degeneration in various organs. All of the miRNAs outperformed ALT, AST, and/or CK in studies with either liver or skeletal muscle injury and demonstrated superior specificity in organs without type-specific injury (eg, liver biomarkers assessed with compounds that cause skeletal muscle injury). When additional protein biomarkers were included, glutamate dehydrogenase, arginase I, alpha-glutathione S-transferase for liver and skeletal troponin I, myosin light chain 3, fatty acid-binding protein 3, and creatine kinase M isoform for skeletal muscle, the miRNAs demonstrated equal or superior performance to the extended panel. Taken together, this comprehensive evaluation demonstrates that these novel miRNA toxicity biomarkers outperform and add value with respect to sensitivity and specificity over ALT, AST in monitoring the liver and over CK for monitoring skeletal muscle drug-induced injury.

Evaluation of hepatoprotective activity of Syringa oblata leaves ethanol extract with the indicator of glutathione S-transferase A1

The leaves of Syringa oblata Lindl., Oleaceae, had been extensively used as a folk medicine to treat various infections, heal inflammations, icteric hepatitis and acute mastitis. The study was designed to evaluate the hepatoprotective activity of S. oblata leaves ethanol extract against CCl4-induced hepatotoxicity in primary hepatocytes and mice with the indicator of glutathione S-transferase alpha 1. The hepatoprotective effects of S. oblata leaves ethanol extract were evaluated on the basis of liver histopathology and biochemical parameters as well as hepatic oxidative stress markers. The results showed that CCl4 negatively modulated biochemical parameters and liver antioxidant activities. However, the use of S. oblata leaves ethanol extract restored altered-serum biochemical parameters and liver antioxidant activities in a dose-dependent manner. Importantly, the trends in S-transferase alpha 1 were similar to alanine aminotransferase and aspartate aminotransferase level, and S-transferase alpha 1 was suggested to be a marker for the evaluation of hepatoprotective activity of S. oblata leaves ethanol extract. Histopathological examination showed that CCl4 causes significant hepatic injury relative to control group. The above findings suggested that S. oblata leaves ethanol extract has hepatoprotective effects against CCl4-induced hepatic injury and S-transferase alpha 1 may be an indicator to evaluate the protective effects of S. oblata leaves ethanol extract.

Glutathione S-Transferase Alpha 4 Prevents Dopamine Neurodegeneration in a Rat Alpha-Synuclein Model of Parkinson's Disease.

Parkinson’s disease (PD) is a common, progressive neurodegenerative disease, which typically presents itself with a range of motor symptoms, like resting tremor, bradykinesia, and rigidity, but also non-motor symptoms such as fatigue, constipation, and sleep disturbance. Neuropathologically, PD is characterized by loss of dopaminergic cells in the substantia nigra pars compacta (SNpc) and Lewy bodies, neuronal inclusions containing α-synuclein (α-syn). Mutations and copy number variations of SNCA, the gene encoding α-syn, are linked to familial PD and common SNCA gene variants are associated to idiopathic PD. Large-scale genome-wide association studies have identified risk variants across another 40 loci associated to idiopathic PD. These risk variants do not, however, explain all the genetic contribution to idiopathic PD. The rat Vra1 locus has been linked to neuroprotection after nerve- and brain injury in rats. Vra1 includes the glutathione S-transferase alpha 4 (Gsta4) gene, which encodes a protein involved in clearing lipid peroxidation by-products. The DA.VRA1 congenic rat strain, carrying PVG alleles in Vra1 on a DA strain background, was recently reported to express higher levels of Gsta4 transcripts and to display partial neuroprotection of SNpc dopaminergic neurons in a 6-hydroxydopamine (6-OHDA) induced model for PD. Since α-syn expression increases the risk for PD in a dose-dependent manner, we assessed the neuroprotective effects of Vra1 in an α-syn-induced PD model. Human wild-type α-syn was overexpressed by unilateral injections of the rAAV6-α-syn vector in the SNpc of DA and DA.VRA1 congenic rats. Gsta4 gene expression levels were significantly higher in the striatum and midbrain of DA.VRA1 compared to DA rats at 3 weeks post surgery, in both the ipsilateral and contralateral sides. At 8 weeks post surgery, DA.VRA1 rats suffered significantly lower fiber loss in the striatum and lower loss of dopaminergic neurons in the SNpc compared to DA. Immunofluorescent stainings showed co-expression of Gsta4 with Gfap at 8 weeks suggesting that astrocytic expression of Gsta4 underlies Vra1-mediated neuroprotection to α-syn induced pathology. This is the second PD model in which Vra1 is linked to protection of the nigrostriatal pathway, solidifying Gsta4 as a potential therapeutic target in PD.

Genetic polymorphisms of cytochrome P450 2D6 (CYP2D6) are associated with long term tramadol treatment-induced oxidative damage and hepatotoxicity

Our objective was to figure out whether CYP2D6 gene polymorphisms may account for long term tramadol-induced oxidative stress and hepatotoxicity in 60 patients receiving chronic tramadol treatment in Neurology and Rheumatology Outpatients Clinic, Zagazig University Hospitals, Egypt. As expected, CYP2D6*1 allele (wild type) frequency was significantly greater than CYP2D6*DUP, CYP2D6*4 and CYP2D6*10 alleles in both chronically tramadol-treated and control groups. In tramadol-treated patients, CYP2D6*DUP allele carriers followed by those carrying CYP2D6*1, displayed higher levels of urinary tramadol major active metabolite, O-desmethyltramadol (M1) and serum lipid peroxidation along with lower levels of total antioxidants than those carrying other impaired function alleles (CYP2D6*4&*10), suggesting oxidative stress. There were also significant increases in serum hepatic damage markers including alpha-glutathione transferase (α-GST) levels and liver function enzyme activities in *DUP and *1 carriers compared to carriers of other alleles. Moreover, we reported that in 42 patients with allele *1, tramadol caused mild to moderate hepatotoxicity (grades: 1–2) within 13–16 months while in 7 patients with duplicated allele (*DUP), tramadol caused moderate to severe hepatotoxicity (grades: 2–3) within 10–11 months (moderately longer period but shorter than that observed in allele *1), implying that exposure to tramadol for longer time in extensive and ultra-rapid metabolizers may contribute to hepatotoxicity development. Overall, our results suggest that CYP2D6 gene polymorphisms, particularly enhanced or normal function of CYP2D6, may increase the vulnerability to long term tramadol-induced hepatotoxicity through the enhancement of accumulation of tramadol bioactive metabolite (M1) and hence oxidative stress. Therefore, tramadol doses should be adjusted according to patient's CYP2D6 genotyping analysis to avoid hepatotoxicity.

Multiscale Mathematical Model of Drug-Induced Proximal Tubule Injury: Linking Urinary Biomarkers to Epithelial Cell Injury and Renal Dysfunction.

Drug-induced nephrotoxicity is a major cause of acute kidney injury, and thus detecting the potential for nephrotoxicity early in the drug development process is critical. Various urinary biomarkers exhibit different patterns following drug-induced injury, which may provide greater information than traditional biomarkers like serum creatinine. In this study, we developed a multiscale quantitative systems pharmacology model relating drug exposure to proximal tubule (PT) epithelial cell injury and subsequently to expression of multiple urinary biomarkers and organ-level functional changes. We utilized urinary kidney injury molecule-1 (Kim-1), alpha glutathione S-transferase, albumin (αGST), glucose, and urine volume time profiles as well as serum creatinine and histopathology data obtained from rats treated with the nephrotoxicant cisplatin to develop the model. Although the model was developed using single-dose response to cisplatin, the model predicted the serum creatinine response to multidose cisplatin regimens. Further, using only the urinary Kim-1 response to gentamicin (a nephrotoxicant with a distinctly different injury time course than cisplatin), the model detected and predicted mild to moderate PT injury, as confirmed with histopathology, even when serum creatinine was unchanged. Thus, the model is generalizable, and can be used to deconvolute the underlying degree and time course of drug-induced PT injury and renal dysfunction from a small number of urinary biomarkers, and may provide a tool to determine optimal dosing regimens that minimize renal injury.

Astrocytic Expression of GSTA4 Is Associated to Dopaminergic Neuroprotection in a Rat 6-OHDA Model of Parkinson’s Disease

Idiopathic Parkinson’s disease (PD) is a complex disease caused by multiple, mainly unknown, genetic and environmental factors. The Ventral root avulsion 1 (Vra1) locus on rat chromosome 8 includes the Glutathione S-transferase alpha 4 (Gsta4) gene and has been identified in crosses between Dark Agouti (DA) and Piebald Virol Glaxo (PVG) rat strains as being associated to neurodegeneration after nerve and brain injury. The Gsta4 protein clears lipid peroxidation by-products, a process suggested to being implicated in PD. We therefore investigated whether PVG alleles in Vra1 are neuroprotective in a toxin-induced model of PD and if this effect is coupled to Gsta4. We performed unilateral 6-hydroxydopamine (6-OHDA) partial lesions in the striatum and compared the extent of neurodegeration in parental (DA) and congenic (DA.VRA1) rats. At 8 weeks after 6-OHDA lesion, DA.VRA1 rats displayed a higher density of remaining dopaminergic fibers in the dorsolateral striatum compared to DA rats (44% vs. 23%, p < 0.01), indicating that Vra1 alleles derived from the PVG strain protect dopaminergic neurons from 6-OHDA toxicity. Gsta4 gene expression levels in the striatum and midbrain were higher in DA.VRA1 congenic rats compared to DA at 2 days post-lesion (p < 0.05). The GSTA4 protein co-localized with astrocytic marker GFAP, but not with neuronal marker NeuN or microglial marker IBA1, suggesting astrocyte-specific expression. This is the first report on Vra1 protective effects on dopaminergic neurodegeneration and encourages further studies on Gsta4 in relation to PD susceptibility.

Enrichment of common carp (Cyprinus carpio) diet with medlar (Mespilus germanica) leaf extract: Effects on skin mucosal immunity and growth performance

A feeding trial was performed to assess the effects of dietary Medlar (Mespilus germanica) leaf extract (MLE) on the growth performance, skin mucus non-specific immune parameters as well as mRNA levels of immune and antioxidant related genes in the skin of common carp (Cyprinus carpio) fingerlings. Fish were fed diets supplemented with graded levels (0, 0.25, 0.50, and 1.00%) of MLE for 49 days. The results revealed an improvement to the growth performance and feed conversion ratio in MLE fed carps (P < 0.05), regardless of the inclusion level. The immunoglobulin levels and interleukin 8 levels in the skin mucous and skin, respectively, revealed significant increment in fish fed 1% MLE (P < 0.05) in comparison with the other MLE treatments and control group. Also, feeding on 0.25% and 0.50% MLE remarkably increased skin mucus lysozyme activity (P < 0.05). However, there were no significant difference between MLE treated groups and control (P > 0.05) in case protease activity in the skin mucous or tumor necrosis factor alpha and interleukin 1 beta gene expression in the skin of carps (P > 0.05). The expression of genes encoding glutathione reductase and glutathione S-transferase alpha were remarkably increased in MLE fed carps compared to the control group (P < 0.05) while carp fed 0.50% or 1.00% MLE had significantly increased glutathione peroxidase expression in their skin (P < 0.05). The present results revealed the potentially beneficial effects of MLE on the mucosal immune system and growth performance in common carp fingerlings.