G2Cdb::Gene report

Gene id
G00002192
Gene symbol
GPX4 (HGNC)
Species
Homo sapiens
Description
glutathione peroxidase 4 (phospholipid hydroperoxidase)
Orthologue
G00000943 (Mus musculus)

Databases (7)

Gene
ENSG00000167468 (Ensembl human gene)
2879 (Entrez Gene)
820 (G2Cdb plasticity & disease)
GPX4 (GeneCards)
Literature
138322 (OMIM)
Marker Symbol
HGNC:4556 (HGNC)
Protein Sequence
P36969 (UniProt)

Synonyms (2)

  • MCSP
  • PHGPx

Literature (54)

Pubmed - other

  • Genetic susceptibility to distinct bladder cancer subphenotypes.

    Guey LT, García-Closas M, Murta-Nascimento C, Lloreta J, Palencia L, Kogevinas M, Rothman N, Vellalta G, Calle ML, Marenne G, Tardón A, Carrato A, García-Closas R, Serra C, Silverman DT, Chanock S, Real FX, Malats N and EPICURO/Spanish Bladder Cancer Study investigators

    Spanish National Cancer Research Centre, Madrid, Spain.

    Background: Clinical, pathologic, and molecular evidence indicate that bladder cancer is heterogeneous with pathologic/molecular features that define distinct subphenotypes with different prognoses. It is conceivable that specific patterns of genetic susceptibility are associated with particular subphenotypes.

    Objective: To examine evidence for the contribution of germline genetic variation to bladder cancer heterogeneity.

    The Spanish Bladder Cancer/EPICURO Study is a case-control study based in 18 hospitals located in five areas in Spain. Cases were patients with a newly diagnosed, histologically confirmed, urothelial cell carcinoma of the bladder from 1998 to 2001. Case diagnoses were reviewed and uniformly classified by pathologists following the World Health Organisation/International Society of Urological Pathology 1999 criteria. Controls were hospital-matched patients (n=1149).

    Measurements: A total of 1526 candidate variants in 423 candidate genes were analysed. Three distinct subphenotypes were defined according to stage and grade: low-grade nonmuscle invasive (n=586), high-grade nonmuscle invasive (n=219), and muscle invasive (n=246). The association between each variant and subphenotype was assessed by polytomous risk models adjusting for potential confounders. Heterogeneity in genetic susceptibility among subphenotypes was also tested.

    Two established bladder cancer susceptibility genotypes, NAT2 slow-acetylation and GSTM1-null, exhibited similar associations among the subphenotypes, as did VEGF-rs25648, which was previously identified in our study. Other variants conferred risks for specific tumour subphenotypes such as PMS2-rs6463524 and CD4-rs3213427 (respective heterogeneity p values of 0.006 and 0.004), which were associated with muscle-invasive tumours (per-allele odds ratios [95% confidence interval] of 0.56 [0.41-0.77] and 0.71 [0.57-0.88], respectively) but not with non-muscle-invasive tumours. Heterogeneity p values were not robust in multiple testing according to their false-discovery rate.

    Conclusions: These exploratory analyses suggest that genetic susceptibility loci might be related to the molecular/pathologic diversity of bladder cancer. Validation through large-scale replication studies and the study of additional genes and single nucleotide polymorphisms are required.

    Funded by: Intramural NIH HHS: ZIA CP010136-16

    European urology 2010;57;2;283-92

  • Association between genetic variants in VEGF, ERCC3 and occupational benzene haematotoxicity.

    Hosgood HD, Zhang L, Shen M, Berndt SI, Vermeulen R, Li G, Yin S, Yeager M, Yuenger J, Rothman N, Chanock S, Smith M and Lan Q

    Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892-7240, USA. hosgoodd@mail.nih.gov

    Introduction: Benzene is an established human haematotoxin, with substantial interindividual variation in benzene-induced toxicity.

    Methods: To further examine if genetic variation contributes to benzene haematotoxicity, we analysed 1023 tagSNPs in 121 gene regions important for benzene metabolism, haematopoiesis, leukaemia and lymphoma among 250 workers exposed to benzene and 140 unexposed controls in a cross-sectional study carried out in China. Linear regression was used to analyse the relationship between genetic polymorphisms and total white blood cell (WBC) count and its subtypes, adjusting for potential confounders and occupational exposure to benzene and toluene among exposed workers. The minp test assessed the association on the gene region level. The false discovery rate method was used to control for multiple comparisons.

    Results: VEGF (minp = 0.0030) and ERCC3 (minp = 0.0042) were the most significantly associated gene regions with altered WBC counts among benzene-exposed workers, after accounting for multiple comparisons. Highly significant changes were also found for WBC subtype counts, including granulocytes, CD4+ T cells and lymphocytes for VEGF and granulocytes and NK cells for ERCC3. Further, in workers exposed to <1 ppm, a SNP in VEGF was associated with changes in WBC and granulocyte counts, and SNPs in ERCC3 were associated with changes in WBC, NK cell and granulocyte counts.

    Discussion: Our findings suggest that genetic variation in VEGF, which plays an important role in blood vessel growth, and ERCC3, which is a member of the DNA repair pathway and is responsible for repairing bulky DNA adducts formed by chemicals, may contribute to individual susceptibility to benzene-induced haematotoxicity at relatively low levels of benzene exposure.

    Funded by: Intramural NIH HHS: Z99 CA999999; NIEHS NIH HHS: P30 ES001896, P30ES01896, P42 ES004705, P42ES04705, R01 ES006721, R01ES06721

    Occupational and environmental medicine 2009;66;12;848-53

  • PTEN identified as important risk factor of chronic obstructive pulmonary disease.

    Hosgood HD, Menashe I, He X, Chanock S and Lan Q

    Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.

    Common genetic variation may play an important role in altering chronic obstructive pulmonary disease (COPD) risk. In Xuanwei, China, the COPD rate is more than twice the Chinese national average, and COPD is strongly associated with in-home coal use. To identify genetic variation that may be associated with COPD in a population with substantial in-home coal smoke exposures, we evaluated 1261 single nucleotide polymorphisms (SNPs) in 380 candidate genes potentially relevant for cancer and other human diseases in a population-based case-control study in Xuanwei (53 cases; 107 controls). PTEN was the most significantly associated gene with COPD in a minP analysis using 20,000 permutations (P=0.00005). SNP-based analyses found that homozygote variant carriers of PTEN rs701848 (OR(TT)=0.12, 95% CI=0.03-0.47) had a significant decreased risk of COPD. PTEN, or phosphatase and tensin homolog, is an important regulator of cell cycle progression and cellular survival via the AKT signaling pathway. Our exploratory analysis suggests that genetic variation in PTEN may be an important risk factor of COPD in Xuanwei. However, due to the small sample size, additional studies are needed to evaluate these associations within Xuanwei and other populations with coal smoke exposures.

    Funded by: Intramural NIH HHS: Z99 CA999999

    Respiratory medicine 2009;103;12;1866-70

  • Short form glutathione peroxidase 4 is the essential isoform required for survival and somatic mitochondrial functions.

    Liang H, Yoo SE, Na R, Walter CA, Richardson A and Ran Q

    Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229, USA.

    Glutathione peroxidase 4 (Gpx4) is an essential antioxidant enzyme having multiple functions. A long form Gpx4 protein and a short form Gpx4 protein, which are distinguishable by the presence or lack of a mitochondrial signal peptide at the N terminus, are generated from the Gpx4 gene. In this study, we generated transgenic mice using mutated GPX4 genes encoding either the long form Gpx4 (lGPX4 gene) or the short form Gpx4 (sGPX4 gene). Our results showed that transgenic mice with the sGPX4 gene had increased Gpx4 protein in all tissues and were protected against diquat-induced apoptosis in liver. Moreover, the sGPX4 gene was able to rescue the lethal phenotype of the mouse Gpx4-null mutation. In contrast, transgenic mice with the lGPX4 gene had increased Gpx4 protein only in the testes, and the lGPX4 gene failed to rescue the lethal phenotype of the mouse Gpx4-null mutation. In Gpx4-null mice rescued by the sGPX4 gene, the Gpx4 protein was present in mitochondria isolated from somatic tissues, and the submitochondrial distribution pattern of the Gpx4 protein in these mice was identical to that in wild-type mice. Interestingly, the male Gpx4-null mice rescued by the sGPX4 gene were infertile and exhibited sperm malformation. Together, our results demonstrated for the first time that the short form Gpx4 protein is present in somatic tissue mitochondria and is essential for survival and protection against apoptosis in mice, whereas the long form Gpx4 protein is important for male fertility.

    Funded by: NIA NIH HHS: 1P30-AG13319, AG021163, P01 AG019316, P01AG19316, P30 AG013319, R01 AG021163, R37 AG026557

    The Journal of biological chemistry 2009;284;45;30836-44

  • Common genetic variants in candidate genes and risk of familial lymphoid malignancies.

    Liang XS, Caporaso N, McMaster ML, Ng D, Landgren O, Yeager M, Chanock S and Goldin LR

    Genetic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD 20892-7236, USA. liangx2@mail.nih.gov

    Familial aggregation, linkage and case-control studies support the role of germline genes in the aetiology of lymphoid malignancies. To further examine the role of genetic variation underlying susceptibility, we analysed 1536 single nucleotide polymorphisms in 152 genes involved in apoptosis, DNA repair, immune response and oxidative stress pathways among a unique sample of 165 unrelated familial cases including patients with chronic lymphocytic leukaemia (CLL), Waldenström macroglobulinaemia (WM) and Hodgkin lymphoma (HL), and 107 spouse controls. We confirmed previous studies showing a polymorphism in the IL10 promoter (rs1800890/-3575T>A) to be associated with non-Hodgkin lymphoma, as this allele was found to be associated with both CLL and WM. We also confirmed the role of IL6 variation to be associated with HL. Polymorphisms in TNFSF10 were associated with both CLL and WM. Future replication and functional studies are needed to clarify the role of these genetic variants. Finally, our data further support the close association of WM and CLL.

    Funded by: Intramural NIH HHS: ZIA CP004410-33

    British journal of haematology 2009;146;4;418-23

  • Defining the human deubiquitinating enzyme interaction landscape.

    Sowa ME, Bennett EJ, Gygi SP and Harper JW

    Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.

    Deubiquitinating enzymes (Dubs) function to remove covalently attached ubiquitin from proteins, thereby controlling substrate activity and/or abundance. For most Dubs, their functions, targets, and regulation are poorly understood. To systematically investigate Dub function, we initiated a global proteomic analysis of Dubs and their associated protein complexes. This was accomplished through the development of a software platform called CompPASS, which uses unbiased metrics to assign confidence measurements to interactions from parallel nonreciprocal proteomic data sets. We identified 774 candidate interacting proteins associated with 75 Dubs. Using Gene Ontology, interactome topology classification, subcellular localization, and functional studies, we link Dubs to diverse processes, including protein turnover, transcription, RNA processing, DNA damage, and endoplasmic reticulum-associated degradation. This work provides the first glimpse into the Dub interaction landscape, places previously unstudied Dubs within putative biological pathways, and identifies previously unknown interactions and protein complexes involved in this increasingly important arm of the ubiquitin-proteasome pathway.

    Funded by: NIA NIH HHS: AG085011, R01 AG011085, R01 AG011085-16; NIGMS NIH HHS: GM054137, GM67945, R01 GM054137, R01 GM054137-14, R01 GM067945

    Cell 2009;138;2;389-403

  • Leukotriene pathway polymorphisms are associated with altered cysteinyl leukotriene production in children with acute asthma.

    Bizzintino JA, Khoo SK, Zhang G, Martin AC, Rueter K, Geelhoed GC, Goldblatt J, Laing IA, Le Souëf PN and Hayden CM

    School of Paediatrics and Child Health, University of Western Australia, GPO Box D184, Perth, WA 6840, Australia.

    Cysteinyl leukotrienes (cysLTs) are pro-inflammatory mediators with increasing evidence for a role in childhood acute asthma. This study examined the influence of polymorphisms in cysLT pathway genes on urinary leukotriene E(4) (uLTE(4)) levels and clinical status in acute asthmatic children. Children aged 2-16 years were recruited during an asthma attack (n=205). Where possible, asthma severity scores were assigned, ALOX5AP G-336A, ALOX5 G-1708A, LTC4S A-444C and G-1072A, GPX4 C718T, and CYSTLTR1 T927C genotypes were determined and uLTE(4) was measured in acute and convalescent samples. uLTE(4) levels were higher acutely compared with convalescence (acute GM: 115.7pg/mg creatinine; 95% CI 88.6-151.1, convalescence GM: 66.4pg/mg creatinine; 95% CI 51.5-85.6; n=50 paired samples, p=0.003) and paired sample analysis showed genotype-specific effects with significantly increased uLTE(4) for LTC(4)S-444AA (acute GM: 127.9pg/mg creatinine; 95% CI 91.8-178.3, convalescence GM: 68.2pg/mg creatinine; 95% CI 50.5-92.0; n=32, p=0.002), LTC(4)S-1072 GG (acute GM: 126.7pg/mg creatinine; 95% CI 95.4-168.3, convalescence GM: 78.9pg/mg creatinine; 95% CI 59.7-104.1; n=39, p=0.019) and CYSLTR1 927 TT/T_ (acute GM: 96.8pg/mg creatinine; 95% CI 73.8-126.9, convalescence GM: 62.4pg/mg creatinine; 95% CI 46.8-83.3; n=28, p=0.036) but not AC/CC, GA/AA, or TC/CC/C_, respectively. When we compared the allele frequencies of the CYSLTR1 SNP between asthmatics and non-asthmatics, the 927C allele was found to be a risk allele for asthma (OR=2.13, 95% CI: 1.06-4.26, p=0.033). Genotypes were not associated with acute or convalescent uLTE(4) levels alone and neither the SNPs nor uLTE(4) correlated with acute asthma severity. Leukotriene pathway gene polymorphisms may influence the magnitude of cysLT production during an attack, yet their influence alone may not be substantial enough to alter the severity of exacerbations.

    Prostaglandins, leukotrienes, and essential fatty acids 2009;81;1;9-15

  • Specific systemic antioxidant response to preeclampsia in late pregnancy: the study of intracellular glutathione peroxidases in maternal and fetal blood.

    Boutet M, Roland L, Thomas N and Bilodeau JF

    Unité de Recherche en Ontogénie et Reproduction, Centre de Recherche du Centre Hospitalier de l'Université Laval, and Centre de Recherche en Biologie de Reproduction, Queébec, QC, Canada.

    Objective: The physiopathology of preeclampsia is still unclear, but an imbalance between reactive oxygen species (ROS) and antioxidants, also called oxidative stress, appears to be an important contributing factor. The ROS promote lipid oxidation and are known to induce stress proteins, such as hemeoxygenase 1 (HO-1) and heat-shock protein 70 (Hsp-70). We hypothesized that glutathione peroxidases (GPx), a major class of antioxidant enzymes that regulate cell homeostasis by neutralizing lipid peroxides, are altered in the blood of preeclamptic women and neonates (venous cord blood).

    Methods: Thirty-one preeclamptic and 30 normotensive pregnancies were recruited. The blood was fractionated using a discontinuous gradient to separate the different cell types. The messenger ribonucleic acid (mRNA) expression of GPx-1 and -4, HO-1, and Hsp-70 were analyzed by quantitative reverse transcriptase-polymerase chain reaction. GPx-1 and -4 protein level in blood cells was also detected by Western blot. The experiments were analyzed using the Student t test.

    Results: The HO-1 and Hsp-70 mRNA expression in whole blood was significantly higher in both fetal and maternal circulations (P < .05). We also discovered that GPx-4 mRNA was 1.6-fold higher in blood of women with preeclampsia than in control pregnancies (P = .04). The latter was associated with an increase of both GPx-1 and GPx-4 protein and mRNA levels in the lymphocyte/monocyte fraction of the blood. Significantly higher GPx-4 mRNA levels in the fetal circulation of the preeclamptic group than the control group were also detected (P < .001).

    Conclusion: These data indicate that preeclampsia is associated with a specific antioxidant response in both maternal and fetal circulations, likely in response to the deleterious oxidative stress observed in this syndrome.

    American journal of obstetrics and gynecology 2009;200;5;530.e1-7

  • Simultaneous genotyping of 11 non-synonymous SNPs in the 4 glutathione peroxidase genes using the multiplex single base extension method.

    Iida R, Tsubota E, Yuasa I, Takeshita H and Yasuda T

    Division of Forensic Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan. riida@u-fukui.ac.jp

    Background: Glutathione peroxidase (Gpx) is one of the major antioxidant enzymes involved in scavenging hydrogen peroxide and lipid hydroperoxides produced during normal metabolism or after oxidative insult. In the Gpx genes, a number of single nucleotide polymorphisms (SNPs) have been identified and their associations with various diseases have been reported. In the present study, we used a multiplex single base extension (MSBE) technique to genotype multiple non-synonymous SNPs in the Gpx1, Gpx2, Gpx3 and Gpx4 genes simultaneously.

    Methods: Seven templates for the MSBE reaction, involving 11 SNPs corresponding to non-synonymous mutations were amplified by multiplex PCR. Availability of the MSBE method was validated by genotyping DNA from 91 Japanese, 91 German and 93 Xhosa healthy subjects.

    Results: A simple and reproducible method for simultaneous genotyping of multiple SNPs in the Gpx genes was established. Of the 11 SNPs, only Gpx1 P200L was polymorphic in all three ethnic groups and the genotype distributions differed significantly among the three populations. On the other hand, little heterogeneity was observed for Gpx2 R146C, Gpx2 P126L, Gpx1 A194T and Gpx4 S2N, and no heterogeneity was observed for Gpx1 L6P, Gpx1 R5P, Gpx3 F128L, Gpx3 K144X, Gpx4 A88V and Gpx4 S227L.

    Conclusion: The MSBE procedure described here was proven to be applicable for population studies. Application of this method will provide comprehensive information for studying the relationship between SNPs in the Gpx genes and risks for various diseases.

    Clinica chimica acta; international journal of clinical chemistry 2009;402;1-2;79-82

  • Common genetic variation in candidate genes and susceptibility to subtypes of breast cancer.

    Mavaddat N, Dunning AM, Ponder BA, Easton DF and Pharoah PD

    Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom. nm274@cam.ac.uk

    Association studies have been widely used to search for common low-penetrance susceptibility alleles to breast cancer in general. However, breast cancer is a heterogeneous disease and it has been suggested that it may be possible to identify additional susceptibility alleles by restricting analyses to particular subtypes. We used data on 710 single nucleotide polymorphisms (SNP) in 120 candidate genes from a large candidate gene association study of up to 4,470 cases and 4,560 controls to compare the results of analyses of "overall" breast cancer with subgroup analyses based on the major clinicopathologic characteristics of breast cancer (stage, grade, morphology, and hormone receptor status). No SNP was highly significant in overall effects analysis. Subgroup analysis resulted in substantial reordering of ranks of SNPs, as assessed by the magnitude of the test statistics, and some associations that were not significant for an overall effect were detected in subgroups at a nominal 5% level adjusted for multiple testing. The most significant association of CCND1 SNP rs3212879 with estrogen receptor-negative tumor types (P = 0.001) did not reach genome-wide significance levels. These results show that it may be possible to detect associations using subgroup analysis that are missed in overall effects analysis. If the associations we found can be replicated in independent studies, they may provide important insights into disease mechanisms in breast cancer.

    Funded by: Cancer Research UK: 10118, 10119, 10124, A10119, A10124; Medical Research Council

    Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology 2009;18;1;255-9

  • Oxidative stress, telomere length and biomarkers of physical aging in a cohort aged 79 years from the 1932 Scottish Mental Survey.

    Starr JM, Shiels PG, Harris SE, Pattie A, Pearce MS, Relton CL and Deary IJ

    MRC Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Royal Victoria Hospital, Edinburgh EH4 2DN, UK. jstarr@staffmail.ed.ac.uk

    Telomere shortening is a biomarker of cellular senescence and is associated with a wide range of age-related disease. Oxidative stress is also associated with physiological aging and several age-related diseases. Non-human studies suggest that variants in oxidative stress genes may contribute to both telomere shortening and biological aging. We sought to test whether oxidative stress-related gene polymorphisms contribute to variance in both telomere length and physical biomarkers of aging in humans. Telomere lengths were calculated for 190 (82 men, 108 women) participants aged 79 years and associations with 384 SNPs, from 141 oxidative stress genes, identified 9 significant SNPS, of which those from 5 genes (GSTZ1, MSRA, NDUFA3, NDUFA8, VIM) had robust associations with physical aging biomarkers, respiratory function or grip strength. Replication of associations in a sample of 318 (120 males, 198 females) participants aged 50 years confirmed significant associations for two of the five SNPs (MSRA rs4841322, p=0.008; NDUFA8 rs6822, p=0.048) on telomere length. These data indicate that oxidative stress genes may be involved in pathways that lead to both telomere shortening and physiological aging in humans. Oxidative stress may explain, at least in part, associations between telomere shortening and physiological aging.

    Funded by: Biotechnology and Biological Sciences Research Council: S18386; Chief Scientist Office: CZB/4/505, ETM/55; Medical Research Council; Wellcome Trust

    Mechanisms of ageing and development 2008;129;12;745-51

  • Pathway-based evaluation of 380 candidate genes and lung cancer susceptibility suggests the importance of the cell cycle pathway.

    Hosgood HD, Menashe I, Shen M, Yeager M, Yuenger J, Rajaraman P, He X, Chatterjee N, Caporaso NE, Zhu Y, Chanock SJ, Zheng T and Lan Q

    Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. hosgoodd@mail.nih.gov

    Common genetic variation may play an important role in altering lung cancer risk. We conducted a pathway-based candidate gene evaluation to identify genetic variations that may be associated with lung cancer in a population-based case-control study in Xuan Wei, China (122 cases and 111 controls). A total of 1260 single-nucleotide polymorphisms (SNPs) in 380 candidate genes for lung cancer were successfully genotyped and assigned to one of 10 pathways based on gene ontology. Logistic regression was used to assess the marginal effect of each SNP on lung cancer susceptibility. The minP test was used to identify statistically significant associations at the gene level. Important pathways were identified using a test of proportions and the rank truncated product methods. The cell cycle pathway was found as the most important pathway (P = 0.044) with four genes significantly associated with lung cancer (PLA2G6 minP = 0.001, CCNA2 minP = 0.006, GSK3 beta minP = 0.007 and EGF minP = 0.013), after adjusting for multiple comparisons. Interestingly, most cell cycle genes that were associated with lung cancer in this analysis were concentrated in the AKT signaling pathway, which is essential for regulation of cell cycle progression and cellular survival, and may be important in lung cancer etiology in Xuan Wei. These results should be viewed as exploratory until they are replicated in a larger study.

    Funded by: Intramural NIH HHS; NCI NIH HHS: TU2 CA105666

    Carcinogenesis 2008;29;10;1938-43

  • Polymorphisms in the estrogen receptor 1 and vitamin C and matrix metalloproteinase gene families are associated with susceptibility to lymphoma.

    Skibola CF, Bracci PM, Halperin E, Nieters A, Hubbard A, Paynter RA, Skibola DR, Agana L, Becker N, Tressler P, Forrest MS, Sankararaman S, Conde L, Holly EA and Smith MT

    School of Public Health, Division of Environmental Health Sciences, University of California Berkeley, Berkeley, California, USA. chrisfs@berkeley.edu

    Background: Non-Hodgkin lymphoma (NHL) is the fifth most common cancer in the U.S. and few causes have been identified. Genetic association studies may help identify environmental risk factors and enhance our understanding of disease mechanisms.

    768 coding and haplotype tagging SNPs in 146 genes were examined using Illumina GoldenGate technology in a large population-based case-control study of NHL in the San Francisco Bay Area (1,292 cases 1,375 controls are included here). Statistical analyses were restricted to HIV- participants of white non-Hispanic origin. Genes involved in steroidogenesis, immune function, cell signaling, sunlight exposure, xenobiotic metabolism/oxidative stress, energy balance, and uptake and metabolism of cholesterol, folate and vitamin C were investigated. Sixteen SNPs in eight pathways and nine haplotypes were associated with NHL after correction for multiple testing at the adjusted q<0.10 level. Eight SNPs were tested in an independent case-control study of lymphoma in Germany (494 NHL cases and 494 matched controls). Novel associations with common variants in estrogen receptor 1 (ESR1) and in the vitamin C receptor and matrix metalloproteinase gene families were observed. Four ESR1 SNPs were associated with follicular lymphoma (FL) in the U.S. study, with rs3020314 remaining associated with reduced risk of FL after multiple testing adjustments [odds ratio (OR) = 0.42, 95% confidence interval (CI) = 0.23-0.77) and replication in the German study (OR = 0.24, 95% CI = 0.06-0.94). Several SNPs and haplotypes in the matrix metalloproteinase-3 (MMP3) and MMP9 genes and in the vitamin C receptor genes, solute carrier family 23 member 1 (SLC23A1) and SLC23A2, showed associations with NHL risk.

    Our findings suggest a role for estrogen, vitamin C and matrix metalloproteinases in the pathogenesis of NHL that will require further validation.

    Funded by: NCI NIH HHS: CA104862, CA122663, CA87014, CA89745, R01 CA045614, R01 CA087014, R01 CA122663, R03 CA089745; NIEHS NIH HHS: P42 ES004705

    PloS one 2008;3;7;e2816

  • Variation in the selenoenzyme genes and risk of advanced distal colorectal adenoma.

    Peters U, Chatterjee N, Hayes RB, Schoen RE, Wang Y, Chanock SJ and Foster CB

    Public Health Science, Fred Hutchinson Cancer Research Center, PO Box 19024, Seattle, WA 98109-1024, USA. upeters@fhcrc.org

    Background: Epidemiologic and animal studies provide evidence for a chemopreventive effect of selenium on colorectal cancer, which may be mediated by the antioxidative and anti-inflammatory properties of selenoenzymes. We therefore investigated whether genetic variants in selenoenzymes abundantly expressed in the colon are associated with advanced colorectal adenoma, a cancer precursor.

    Methods: Cases with a left-sided advanced adenoma (n = 772) and matched controls (n = 777) screen negative for polyps based on sigmoidoscopy examination were randomly selected from participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. The underlying genetic variation was determined by resequencing. We genotyped 44 tagging single nucleotide polymorphisms (SNP) in six genes [glutathione peroxidase 1-4 (GPX1, GPX2, GPX3, and GPX4), selenoprotein P (SEPP1), and thioredoxin reductase 1 (TXNRD1)] to efficiently predict common variation across these genes.

    Results: Four variants in SEPP1 were significantly associated with advanced adenoma risk. A rare variant in the 5' region of SEPP1 (-4166C>G) was present in nine cases but in none of the controls (exact P = 0.002). Three SNPs located in the 3' region of SEPP1, which is overlapping with the promoter region of an antisense transcript, were significantly associated with adenoma risk: homozygotes at two SEPP1 loci (31,174 bp 3' of STP A>G and 43,881 bp 3' of STP G>A) were associated with increased adenoma risk [odds ratio (OR), 1.48; 95% confidence interval (95% CI), 1.00-2.19 and OR, 1.53; 95% CI, 1.05-2.22, respectively] and the variant SEPP1 44,321 bp 3' of STP C>T was associated with a reduced adenoma risk (CT versus CC OR, 0.85; 95% CI, 0.63-1.15). Furthermore, we observed a significant 80% reduction for advanced colorectal adenoma risk for carriers of the variant allele at TXNRD1 IVS1-181C>G (OR, 0.20; 95% CI, 0.07-0.55; P trend = 0.004). Consistent with the individual SNP results, we observed a significant overall association with adenoma risk for SEPP1 and TXNRD1 (global P = 0.02 and 0.008, respectively) but not for the four GPX genes.

    Conclusion: Our study suggests that genetic variants at or near the SEPP1 and TXNRD1 loci may be associated with advanced colorectal adenoma. As this is the first study to comprehensively investigate this hypothesis, confirmation in independent study populations is needed.

    Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology 2008;17;5;1144-54

  • Functional effects of a common single-nucleotide polymorphism (GPX4c718t) in the glutathione peroxidase 4 gene: interaction with sex.

    Méplan C, Crosley LK, Nicol F, Horgan GW, Mathers JC, Arthur JR and Hesketh JE

    Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle, United Kingdom.

    Background: Selenium is essential for health in humans. Selenium is present as selenocysteine in selenoproteins such as the glutathione peroxidases (GPx). Selenocysteine incorporation requires specific structures in the 3'untranslated region (3'UTR) of selenoprotein mRNAs.

    Objective: This study investigated the functional significance of the single-nucleotide polymorphism (SNP) GPx4c718t within the 3'UTR of the GPx4 gene.

    Design: A selenium supplementation trial was carried out with prospectively genotyped individuals of both homozygote genotypes for this SNP. Blood samples were analyzed at baseline, after a 6-wk supplementation with 100 mug Se as sodium selenite/d, and during a 6-wk washout period. RNA-protein binding studies were carried out in vitro.

    Results: Both lymphocyte GPx1 protein concentrations and plasma GPx3 activity increased significantly after selenium supplementation in CC but not TT participants. After selenium withdrawal, there was a significant fall in both lymphocyte GPx4 protein concentrations and GPx4 activity in TT but not in CC participants; this effect was modulated by sex. RNA-protein binding assays showed that both T and C variants of transcripts corresponding to the GPx4 3'UTR formed complexes in vitro and that the C variant bound more strongly than did either the T variant or the GPx1 3'UTR.

    Conclusions: The GPX4c718t SNP both alters protein binding to the 3'UTR in vitro and influences the concentration of lymphocyte GPx4 and other selenoproteins in vivo. The latter is consistent with competition for selenium in selenoprotein synthesis, and, at low selenium intake, the SNP thus may influence susceptibility to disease.

    The American journal of clinical nutrition 2008;87;4;1019-27

  • Structural basis for catalytic activity and enzyme polymerization of phospholipid hydroperoxide glutathione peroxidase-4 (GPx4).

    Scheerer P, Borchert A, Krauss N, Wessner H, Gerth C, Höhne W and Kuhn H

    Institute of Biochemistry, University Medicine Berlin-Charité, Monbijoustr. 2, D-10117 Berlin, Germany.

    Phospholipid hydroperoxide glutathione peroxidase (GPx4) is a moonlighting selenoprotein, which has been implicated in anti-oxidative defense, sperm development, and cerebral embryogenesis. Among GPx-isoforms, GPx4 is unique because of its capability to reduce complex lipid hydroperoxides and its tendency toward polymerization, but the structural basis for these properties remained unclear. To address this, we solved the crystal structure of the catalytically active U46C mutant of human GPx4 to 1.55 A resolution. X-ray data indicated a monomeric protein consisting of four alpha-helices and seven beta-strands. GPx4 lacks a surface exposed loop domain, which appears to limit the accessibility of the active site of other GPx-isoforms, and these data may explain the broad substrate specificity of GPx4. The catalytic triad (C46, Q81, and W136) is localized at a flat impression of the protein surface extending into a surface exposed patch of basic amino acids (K48, K135, and R152) that also contains polar T139. Multiple mutations of the catalytic triad indicated its functional importance. Like the wild-type enzyme, the U46C mutant exhibits a strong tendency toward protein polymerization, which was prevented by reductants. Site-directed mutagenesis suggested involvement of the catalytic C46 and surface exposed C10 and C66 in polymer formation. In GPx4 crystals, these residues contact adjacent protein monomers.

    Biochemistry 2007;46;31;9041-9

  • Common germline genetic variation in antioxidant defense genes and survival after diagnosis of breast cancer.

    Udler M, Maia AT, Cebrian A, Brown C, Greenberg D, Shah M, Caldas C, Dunning A, Easton D, Ponder B and Pharoah P

    Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom. miriam.udler@srl.cam.ac.uk

    Purpose: The prognosis of breast cancer varies considerably among individuals, and inherited genetic factors may help explain this variability. Of particular interest are genes involved in defense against reactive oxygen species (ROS) because ROS are thought to cause DNA damage and contribute to the pathogenesis of cancer.

    We examined associations between 54 polymorphisms that tag the known common variants (minor allele frequency > 0.05) in 10 genes involved in oxidative damage repair (CAT, SOD1, SOD2, GPX1, GPX4, GSR, TXN, TXN2, TXNRD1, and TXNRD2) and survival in 4,470 women with breast cancer.

    Results: Two single nucleotide polymorphisms (SNPs) in GPX4 (rs713041 and rs757229) were associated with all-cause mortality even after adjusting for multiple hypothesis testing (adjusted P = .0041 and P = .0035). These SNPs are correlated with each other (r2 = 0.61). GPX4 rs713041 is located near the selenocysteine insertion sequence element in the GPX4 3' untranslated region, and the rare allele of this SNP is associated with an increased risk of death, with a hazard ratio of 1.27 per rare allele carried (95% CI, 1.13 to 11.43). This effect was not attenuated after adjusting for tumor stage, grade, or estrogen receptor status. We found that the common allele is preferentially expressed in normal lymphocytes, normal breast, and breast tumors compared with the rare allele, but there were no differences in total levels of GPX4 mRNA across genotypes.

    Conclusion: These data provide strong support for the hypothesis that common variation in GPX4 is associated with prognosis after a diagnosis of breast cancer.

    Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2007;25;21;3015-23

  • A genetic association analysis of cognitive ability and cognitive ageing using 325 markers for 109 genes associated with oxidative stress or cognition.

    Harris SE, Fox H, Wright AF, Hayward C, Starr JM, Whalley LJ and Deary IJ

    Department of Psychology, University of Edinburgh, Edinburgh, UK. Sarah.Harris@hgu.mrc.ac.uk <Sarah.Harris@hgu.mrc.ac.uk&gt;

    Background: Non-pathological cognitive ageing is a distressing condition affecting an increasing number of people in our 'ageing society'. Oxidative stress is hypothesised to have a major role in cellular ageing, including brain ageing.

    Results: Associations between cognitive ageing and 325 single nucleotide polymorphisms (SNPs), located in 109 genes implicated in oxidative stress and/or cognition, were examined in a unique cohort of relatively healthy older people, on whom we have cognitive ability scores at ages 11 and 79 years (LBC1921). SNPs showing a significant positive association were then genotyped in a second cohort for whom we have cognitive ability scores at the ages of 11 and 64 years (ABC1936). An intronic SNP in the APP gene (rs2830102) was significantly associated with cognitive ageing in both LBC1921 and a combined LBC1921/ABC1936 analysis (p < 0.01), but not in ABC1936 alone.

    Conclusion: This study suggests a possible role for APP in normal cognitive ageing, in addition to its role in Alzheimer's disease.

    Funded by: Medical Research Council: MC_U127561128

    BMC genetics 2007;8;43

  • Phospholipid hydroperoxide glutathione peroxidase (PHGPx) expression is downregulated in poorly differentiated breast invasive ductal carcinoma.

    Cejas P, García-Cabezas MA, Casado E, Belda-Iniesta C, De Castro J, Fresno JA, Sereno M, Barriuso J, Espinosa E, Zamora P, Feliu J, Redondo A, Hardisson DA, Renart J and González-Barón M

    Medical Oncology Service, Hospital Universitario La Paz, Madrid, Spain.

    Phospholipid Hydroperoxide Glutathione Peroxidase (PHGPx) is the only known enzyme able to reduce lipid peroxides bound to cell membranes. Moreover it has been involved in apoptosis and can influence intracellular signaling. To investigate the possible relationship between PHGPx and human cancer we have quantified PHGPx expression levels by real-time quantitative PCR and immunohistochemistry in tissue samples of human breast invasive ductal carcinoma from 34 patients compared with their own controls of benign breast tissue. PHGPx expression levels were compared with the clinical and pathological data of these patients. The results showed that PHGPx expression levels are downregulated in poorly differentiated (grade 3) breast invasive ductal carcinoma (P = 0.0043). PHGPx expression levels decreased gradually with tumor grade from grade 1 to grade 3. We also found a downregulation of PHGPx in cases that showed p53 accumulation compared with cases without p53 immunostaining (P = 0.0011). PHGPx was also downregulated in cases without progesterone receptors (PR) immunostaining compared with cases with PR immunostaining (P = 0.0165). Grade 3, p53 immunostaining and absence of PR immunostaining are poor prognostic factors. These results suggest that PHGPx downregulation could be related with a poorer prognosis in breast invasive ductal carcinoma.

    Free radical research 2007;41;6;681-7

  • Effects of selenium supplementation on expression of glutathione peroxidase isoforms in cultured human lung adenocarcinoma cell lines.

    Romanowska M, Kikawa KD, Fields JR, Maciag A, North SL, Shiao YH, Kasprzak KS and Anderson LM

    Laboratory of Comparative Carcinogenesis, National Cancer Institute at Frederick, Building 538, Ft. Detrick, Frederick, MD 21702, USA. mromanowska@ncifcrf.gov

    Selenium is an essential nutrient, a component of several anti-oxidant enzymes, and a possible factor in cancer risk, including lung cancer. We determined the subtoxic range of selenium concentration (as sodium selenite) required to increase and maintain the expression of anti-oxidant selenoproteins gluthathione peroxidases GPX1 and GPX4 at a constant level in cultures of human lung adenocarcinoma cell lines (H460, H1703 and H1944) and in HPL1D, a non-transformed lung epithelial cell line. Selenium dose-dependently increased GPX1 protein expression 1.8-fold in HPL1D cells and approximately 40-fold in H460 and H1944 cancer cells, with maximum effects at 20-40 nM. GPX4 protein was also increased, but more so in HPL1D (five-fold) than in H460 or H1944 cells (two- to three-fold). GPX1 mRNA showed similar patterns but differences of lesser magnitude. GPX1 protein and activity level was not consistently detectable in H1703 cells, with or without Se supplementation; its mRNA was present but very low. GPX4 protein level was also low in H1703 cells, but was markedly increased by selenium supplementation (48-fold). These results confirm a role for selenium in risk of lung cancer and the independent regulation of GPX1 and GPX4. Characterization of individual tumors with regard to GPX1 and GPX4 levels and regulation might be useful for interpretation of clinical studies on effects of selenium in lung cancer risk.

    Funded by: Intramural NIH HHS

    Lung cancer (Amsterdam, Netherlands) 2007;55;1;35-42

  • Effect of sperm glutathione peroxidases 1 and 4 on embryo asymmetry and blastocyst quality in oocyte donation cycles.

    Meseguer M, de los Santos MJ, Simón C, Pellicer A, Remohí J and Garrido N

    Instituto Valenciano de Infertilidad Valencia, Universidad de Valencia, Valencia, Spain. marcos.meseguer@ivi.es

    Objective: To prospectively determine the impact of concrete components of the sperm oxidative glutathione stress system in terms of enzymatic activity and mitochondrial RNA (mRNA) expression on embryo quality and reproductive outcome. Human spermatozoa use the glutathione system to inactivate reactive oxygen metabolites, and there is a close correlation between some components of the glutathione system and male fertility. However, very few data are published regarding this system in sperm cells and its effect on fertilization ability and embryo development in human beings.

    Design: An oocyte-donation model, used to homogenize the female factor.

    Setting: University-affiliated private IVF setting.

    Semen samples from infertile males (n = 43) of couples undergoing oocyte-donation cycles (n = 43).

    None.

    Gene expression and activity of glutathione peroxidases (GPXs) 1 and 4, glutathione reductase, and intracellular glutathione (GSH) by fluorescent quantitative polymerase chain reaction and spectrophotometry, respectively.

    Fertilization rate, pronuclear number, asymmetry, and pronuclear body distribution were not correlated with any sperm glutathione parameters that were considered. When day 3 embryo parameters were evaluated, only GPX4 mRNA expression in sperm cells was statistically significantly lower when asymmetric embryos were observed. Also, worst embryo development and morphology on day 5 was statistically significantly correlated with lower sperm GPX1 activity (101.07 vs. 258.8 IU/mg protein). Glutathione system analysis in fresh sperm was not statistically significantly different in patients achieving pregnancy compared with those who not, and we did not find any correlation with implantation rate.

    We have been able to correlate embryo morphology on day 3 with the sperm expression of GPX family members. The results indicate that sperm-derived mRNA may condition human embryo quality and persist even to blastocyst stage. The correlation of the sperm GPX family mRNA expression with embryo health appears quite promising for discovery of molecular causes of male infertility.

    Fertility and sterility 2006;86;5;1376-85

  • Phospholipid-hydroperoxide glutathione peroxidase (GPx-4) localization in resting platelets, and compartmental change during platelet activation.

    Januel C, El Hentati FZ, Carreras M, Arthur JR, Calzada C, Lagarde M and Véricel E

    Inserm, U585, Villeurbanne, F-69100 France.

    Seleno-glutathione peroxidases are an important family of antioxidant enzymes, that include the phospholipid hydroperoxide glutathione peroxidase (GPx-4), an enzyme that reduces lipid hydroperoxides in membranes. The essential characteristics of platelet GPx-4 were found to be the same as the GPx-4 from other tissues. To explore the subcellular expression of GPx-4 in human platelets, we first investigated both its activity and localization in subcellular fractions. About 47% of the total cell enzyme activity was found in the membrane fractions, 29% in the mitochondria and 23% in the cytosol fractions. The same subcellular distribution of GPx-4 protein was demonstrated in resting platelets. This distribution data was further established by confocal microscopy. Of major potential biological significance, this distribution changed when platelets were activated. Confocal immunofluorescence microscopy localized mainly GPx-4 to membranes in contrast to cytoplasm in the resting cells. Based on these results we propose that cytoplasmic GPx-4 could be moved to the membrane for protection during platelet activation. This enzyme would then be important to maintain the integrity of platelet function in vascular system stressed by oxidative reactions.

    Biochimica et biophysica acta 2006;1761;10;1228-34

  • Interactions between genes involved in the antioxidant defence system and breast cancer risk.

    Oestergaard MZ, Tyrer J, Cebrian A, Shah M, Dunning AM, Ponder BA, Easton DF and Pharoah PD

    Department of Public Health and Primary Care, Strangeways Research Laboratories, Cambridge CB1 8RN, UK. mzo20@cam.ac.uk

    The aim of the study is to examine the association between multilocus genotypes across 10 genes encoding proteins in the antioxidant defence system and breast cancer. The 10 genes are SOD1, SOD2, GPX1, GPX4, GSR, CAT, TXN, TXN2, TXNRD1 and TXNRD2. In all, 2271 cases and 2280 controls were used to examine gene-gene interactions between 52 single nucleotide polymorphisms (SNPs) that are hypothesised to tag all common variants in the 10 genes. The statistical analysis is based on three methods: unconditional logistic regression, multifactor dimensionality reduction and hierarchical cluster analysis. We examined all two- and three-way combinations with unconditional logistic regression and multifactor dimensionality reduction, and used a global approach with all SNPs in the hierarchical cluster analysis. Single-locus studies of an association of genetic variants in the antioxidant defence genes and breast cancer have been contradictory and inconclusive. It is the first time, to our knowledge, the association between multilocus genotypes across genes coding for antioxidant defence enzymes and breast cancer is investigated. We found no evidence of an association with breast cancer with our multilocus approach. The search for two-way interactions gave experiment-wise significance levels of P=0.24 (TXN [t2715c] and TXNRD2 [g23524a]) and P=0.58 (GSR [c39396t] and TXNRD2 [a442g]), for the unconditional logistic regression and multifactor dimensionality reduction, respectively. The experiment-wise significance levels for the three-way interactions were P=0.94 (GPX4 [t2572c], TXN [t2715c] and TXNRD2 [g23524a]) and P=0.29 (GSR [c39396t], TXN [t2715c] and TXNRD2 [a442g]) for the unconditional logistic regression and multifactor dimensionality reduction, respectively. In the hierarchical cluster analysis neither the average across four rounds with replacement of missing values at random (P=0.12) nor a fifth round with more balanced proportion of missing values between cases and controls (P=0.17) was significant.

    British journal of cancer 2006;95;4;525-31

  • Failure of phospholipid hydroperoxide glutathione peroxidase expression in oligoasthenozoospermia and mutations in the PHGPx gene.

    Diaconu M, Tangat Y, Böhm D, Kühn H, Michelmann HW, Schreiber G, Haidl G, Glander HJ, Engel W and Nayernia K

    Institute of Human Genetics, University of Göttingen, Germany.

    Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a selenoprotein belonging to the family of glutathione peroxidases. PHGPx has long been considered a major antioxidant that, in cooperation with vitamin E, protects biomembranes. To determine the expression pattern of PHGPx mRNA in human, quantitative RT-polymerase chain reaction (PCR) analyses using RNA from different embryonal and adult tissues were performed. A predominant expression was found in testes. In spermatozoa, PHGPx was found to be localized in the mid-piece of spermatozoa. We studied the relationship between spermatozoa PHGPx expression, mutations in PHGPx gene and human oligoasthenozoospermia, a defect in which both the number and the motility of spermatozoa are significantly below normal. Spermatozoa specimens from 45 infertile males were analysed for fertility-related parameters according to World Health Organisation and were classified as suffering from oligoasthenozoospermia. Two patients (4.44%) showed no expression of PHGPx and in nine patients (20.00%), a reduced expression of the enzyme was observed. DNA sequences of various regions of the PHGPx gene (coding, 5'flanking region and intron 1) from these patients and 58 fertile volunteers were analysed for mutations by PCR amplification and direct sequencing. Sequence data revealed no cause/effect relationship for any of the variants. From these data it can be concluded that oligoasthenozoospermia is associated with a decrease in the level of expression of PHGPx in the spermatozoa of some infertile men (24.44%), but is not linked to mutations in PHGPx gene.

    Andrologia 2006;38;4;152-7

  • Tagging single-nucleotide polymorphisms in antioxidant defense enzymes and susceptibility to breast cancer.

    Cebrian A, Pharoah PD, Ahmed S, Smith PL, Luccarini C, Luben R, Redman K, Munday H, Easton DF, Dunning AM and Ponder BA

    Strangeways Research Laboratory, Cancer Research UK Department of Oncology, University of Cambridge,Worts Causeway, Cambridge CB1 8RN, UK. arancha@srl.cam.ac.uk

    It is generally believed that the initiation of breast cancer is a consequence of cumulative genetic damage leading to genetic alterations and provoking uncontrolled cellular proliferation and/or aberrant programmed cell death, or apoptosis. Reactive oxygen species have been related to the etiology of cancer as they are known to be mitogenic and therefore capable of tumor promotion. The aim of this study was to assess the role of common variation in 10 polymorphic genes coding for antioxidant defense enzymes in modulating individual susceptibility to breast cancer using a case-control study (N cases = 4,474 and N controls = 4,580). Both cases and controls were from the East Anglian region of the United Kingdom. We have identified a set of 54 single nucleotide polymorphisms (SNPs) that efficiently tag all the known SNPs in the 10 genes and are also expected to tag any unknown SNPs in each gene. We found no evidence for association of common variants in SOD1, SOD2, GPX1, GPX4, GSR, TXNRD1, and TXN2. There was borderline evidence for association of variants in CAT g27168a {P [2 degrees of freedom (df)] = 0.05}, TXN t2715c [P (2 df) = 0.007], and TXNRD2 A66S and TXNRD2 g23524a (P(trend) = 0.074 and 0.046, respectively). For TXNRD2 A66S [AS versus AA: odds ratio (OR), 1.05; 95% confidence intervals (95% CI), 0.96-1.15; SS versus AA: OR, 1.12; 95% CI, 0.98-1.29], there are bioinformatics data to suggest that it is functional but confirmation in independent data sets is required before they can be regarded as definitive breast cancer susceptibility alleles. Even if confirmed, these four alleles would account for just 0.32% of the excess familial risk of breast cancer.

    Cancer research 2006;66;2;1225-33

  • Transcriptome analysis of human gastric cancer.

    Oh JH, Yang JO, Hahn Y, Kim MR, Byun SS, Jeon YJ, Kim JM, Song KS, Noh SM, Yoo HS, Kim YS and Kim NS

    Laboratory of Human Genomics, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon , 305-333, Korea.

    To elucidate the genetic events associated with gastric cancer, 124,704 cDNA clones were collected from 37 human gastric cDNA libraries, including 20 full-length enriched cDNA libraries of gastric cancer cell lines and tissues from Korean patients. An analysis of the collected ESTs revealed that 97,930 high-quality ESTs coalesced into 13,001 clusters, of which 11,135 clusters (85.6%) were annotated to known ESTs. The analysis of the full-length cDNAs also revealed that 4862 clusters (51.7%) contained at least one putative full-length cDNA clone with an initiation codon, with the average length of the 5' UTR of 140 bp. A large number appear to have a diverse transcription start site (TSS). An examination of the TSS of some genes, such as TEGT and GAPD, using 5' RACE revealed that the predicted TSSs are actually found in human gastric cancer cells and that several TSSs differ depending on the specific gastric cell line. Furthermore, of the human gastric ESTs, 766 genes (9.5%) were present as putative alternatively spliced variants. Confirmation of the predicted spliced isoforms using RT-PCR showed that the predicted isoforms exist in gastric cancer cells and some isoforms coexist in gastric cell lines. These results provide potentially useful information for elucidating the molecular mechanisms associated with gastric oncogenesis.

    Mammalian genome : official journal of the International Mammalian Genome Society 2005;16;12;942-54

  • Antioxidant enzymes and lipid peroxides in children with cerebral palsy.

    Kulak W, Sobaniec W, Solowej E and Sobaniec H

    Department of Pediatric Neurology and Rehabilitation, Medical University of Białystok, Waszyngtona 17, 15-274 Białystok, Poland. kulak@hot.pl

    Impaired antioxidant mechanisms are unable to inactivate free radicals that may induce a number of pathophysiological processes and result in cell injury. Thus, any abnormality in antioxidant defense systems could affect neurodevelopmental processes and could have an important role in the etiology of cerebral palsy (CP). The plasma levels of lipid peroxidation as plasma levels of malondialdehyde (MDA), activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) in plasma and erythrocytes were investigated in 34 CP children and compared with 61 normal controls. SOD, GPx and GR activities were spectrophotometrically assayed. Activities of SOD, GPx and GR in plasma did not differ significantly between CP children and the control group. Activities of erythrocyte GR in the CP patients were significantly lower compared with controls. MDA concentration did not differ statistically between the CP children and healthy subjects. In conclusion our results suggest that increased activities of erythrocyte GPx and decreased erythrocyte GR activities might be due to lesser physical activity of children with CP.

    Life sciences 2005;77;24;3031-6

  • HIV-1 viral proteins gp120 and Tat induce oxidative stress in brain endothelial cells.

    Price TO, Ercal N, Nakaoke R and Banks WA

    Department of Biochemistry, Faculty of Pharmacy, Marmara University, Istanbul 81010, Turkey.

    The blood-brain barrier (BBB) has an important role in the development of AIDS dementia. The HIV-1 envelope glycoprotein (gp120) and transregulatory protein (Tat) of HIV-1 are neurotoxic and cytotoxic and have been implicated in the development of HIV dementia. They are known to cause oxidative stress and are associated with disruption of the BBB. Here, we used an immortalized endothelial cell line from rat brain capillaries, RBE4, to determine whether gp120 and Tat can induce oxidative stress in an in vitro model of the BBB. RBE4 cells were exposed to gp120 or Tat and the levels of reduced glutathione (GSH), oxidized glutathione (GSSG), catalase (CAT) activity, glutathione peroxidase (GPx) activity, and glutathione reductase (GR) activity, and malondialdehyde (MDA) used as measures of oxidative stress. Both gp120 and Tat significantly decreased the levels of intracellular GSH, GPx, and GR and increased the levels of MDA in RBE4 cells, showing that the cells were oxidatively challenged. The ratio of GSH/GSSG, a widely accepted indicator of oxidative stress, was also significantly decreased. These studies show that both of these viral proteins can induce oxidative stress in immortalized BBB endothelial cells.

    Funded by: NINDS NIH HHS: R01 NS41863

    Brain research 2005;1045;1-2;57-63

  • Overexpression of phospholipid-hydroperoxide glutathione peroxidase in human dermal fibroblasts abrogates UVA irradiation-induced expression of interstitial collagenase/matrix metalloproteinase-1 by suppression of phosphatidylcholine hydroperoxide-mediated NFkappaB activation and interleukin-6 release.

    Wenk J, Schüller J, Hinrichs C, Syrovets T, Azoitei N, Podda M, Wlaschek M, Brenneisen P, Schneider LA, Sabiwalsky A, Peters T, Sulyok S, Dissemond J, Schauen M, Krieg T, Wirth T, Simmet T and Scharffetter-Kochanek K

    Department of Dermatology, University of Cologne, 50924 Cologne, Germany.

    Phospholipid-hydroperoxide glutathione peroxidase (PHGPx) exhibits high specific activity in reducing phosphatidylcholine hydroperoxides (PCOOHs) and thus may play a central role in protecting the skin against UV irradiation-triggered detrimental long term effects like cancer formation and premature skin aging. Here we addressed the role of PHGPx in the protection against UV irradiation-induced expression of matrix metalloproteinase-1 (MMP-1). For this purpose, we created human dermal fibroblast cell lines overexpressing human PHGPx. Overexpression led to a significant increase in PHGPx activity. In contrast to a maximal 4.5-fold induction of specific MMP-1 mRNA levels in vector-transfected cells at 24 h after UVA irradiation, no MMP-1 induction occurred at any studied time point after UVA treatment of PHGPx-overexpressing fibroblasts. As interleukin-6 (IL-6) was earlier shown to mediate the UVA induction of MMP-1, we studied whether PHGPx overexpression might interfere with the NFkappaB-mediated IL-6 induction and downstream signaling. Using transient transfections of IL-6 promoter constructs containing NFkappaB binding sites, we observed a high induction of the reporter gene luciferase in vector-transfected control cells and a significantly lower induction in PHGPx-overexpressing fibroblasts following UVA irradiation. Consistently both UVA irradiation and treatment of fibroblasts with PCOOHs led to phosphorylation and nuclear translocation of the p65 subunit, whereas cells overexpressing PHGPx exhibited impaired NFkappaB activation, p65 phosphorylation, and nuclear translocation. In line with this, the PHGPx-overexpressing fibroblasts showed a reduced constitutive and UVA irradiation-induced IL-6 release. After incubating PHGPx-overexpressing cells with PCOOHs a reduced induction of IL-6 was observed. This together with the suppression of UVA irradiation-induced IL-6 release in the presence of Trolox, a chain breaker of PCOOH-initiated lipid peroxidation, indicates that UVA irradiation-induced PCOOHs and subsequent lipid peroxides initiate the NFkappaB-mediated induction of IL-6, which mediates the induction of MMP-1. Our finding is particularly relevant in light of the already available small molecule mimetics of PHGPx.

    The Journal of biological chemistry 2004;279;44;45634-42

  • cAMP-response element modulator-tau activates a distinct promoter element for the expression of the phospholipid hydroperoxide/sperm nucleus glutathione peroxidase gene.

    Tramer F, Vetere A, Martinelli M, Paroni F, Marsich E, Boitani C, Sandri G and Panfili E

    Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy.

    PHGPx (phospholipid hydroperoxide glutathione peroxidase) is a selenoprotein present in at least three isoforms in testis: cytosolic, mitochondrial and nuclear. All of these derive from the same gene and are structurally related with the exception of the snPHGPx (sperm nucleus-specific form), which differs from the others due to the presence of an arginine-rich N-terminus. It has been demonstrated recently that this N-terminus is encoded by an alternative exon located in the first intron of the PHGPx gene. The expression of snPHGPx has been attributed either to an alternative pre-mRNA splicing or to the presence of a distinct promoter region. Nevertheless, the exact molecular mechanism by which the expression of snPHGPx occurs has not been demonstrated so far. Preliminary sequence analysis of the region located upstream of the alternative exon revealed some potential DNA-binding sites, one of which is specific to the binding of CREM (cAMP-response element modulator) transcription factors. By using electrophoretic mobility-shift assays, we demonstrated that both nuclear protein extract from highly purified rat spermatid cells and recombinant CREM-tau protein can specifically bind to this element. Furthermore, we cloned a 1059 bp comprising the intron and the alternative exon for snPHGPx in the pCAT3 reporter vector. By transient transfection experiments, we demonstrated that the expression of the transcription factor CREM-tau can induce the activation of the reporter gene in NIH-3T3 cell line. These results were confirmed by chromatin immunoprecipitation experiments performed on highly purified rat spermatid cells. On the basis of these results, we demonstrate that snPHGPx expression is mediated by the transcription factor CREM-tau, which acts as a cis-acting element localized in the first intron of the PHGPx gene.

    The Biochemical journal 2004;383;Pt 1;179-85

  • The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).

    Gerhard DS, Wagner L, Feingold EA, Shenmen CM, Grouse LH, Schuler G, Klein SL, Old S, Rasooly R, Good P, Guyer M, Peck AM, Derge JG, Lipman D, Collins FS, Jang W, Sherry S, Feolo M, Misquitta L, Lee E, Rotmistrovsky K, Greenhut SF, Schaefer CF, Buetow K, Bonner TI, Haussler D, Kent J, Kiekhaus M, Furey T, Brent M, Prange C, Schreiber K, Shapiro N, Bhat NK, Hopkins RF, Hsie F, Driscoll T, Soares MB, Casavant TL, Scheetz TE, Brown-stein MJ, Usdin TB, Toshiyuki S, Carninci P, Piao Y, Dudekula DB, Ko MS, Kawakami K, Suzuki Y, Sugano S, Gruber CE, Smith MR, Simmons B, Moore T, Waterman R, Johnson SL, Ruan Y, Wei CL, Mathavan S, Gunaratne PH, Wu J, Garcia AM, Hulyk SW, Fuh E, Yuan Y, Sneed A, Kowis C, Hodgson A, Muzny DM, McPherson J, Gibbs RA, Fahey J, Helton E, Ketteman M, Madan A, Rodrigues S, Sanchez A, Whiting M, Madari A, Young AC, Wetherby KD, Granite SJ, Kwong PN, Brinkley CP, Pearson RL, Bouffard GG, Blakesly RW, Green ED, Dickson MC, Rodriguez AC, Grimwood J, Schmutz J, Myers RM, Butterfield YS, Griffith M, Griffith OL, Krzywinski MI, Liao N, Morin R, Morrin R, Palmquist D, Petrescu AS, Skalska U, Smailus DE, Stott JM, Schnerch A, Schein JE, Jones SJ, Holt RA, Baross A, Marra MA, Clifton S, Makowski KA, Bosak S, Malek J and MGC Project Team

    The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline.

    Funded by: PHS HHS: N01-C0-12400

    Genome research 2004;14;10B;2121-7

  • Relationship among standard semen parameters, glutathione peroxidase/glutathione reductase activity, and mRNA expression and reduced glutathione content in ejaculated spermatozoa from fertile and infertile men.

    Garrido N, Meseguer M, Alvarez J, Simón C, Pellicer A and Remohí J

    Instituto Valenciano de Infertilidad Valencia, Andrology Laboratory and Semen Bank, Valencia, Spain. nicolas.gerrido@ivi.es

    Objective: To determine the expression and enzymatic activity of glutathione peroxidase (GPX)-1, GPX-4, and glutathione reductase together with glutathione (GSH) concentrations in spermatozoa from fertile and infertile men.

    Design: Prospective study.

    Setting: University-affiliated private center.

    Fifty-four infertile men undergoing assisted reproduction techniques and 55 fertile sperm donors with pregnancies and newborns by artificial insemination.

    None.

    Analysis of gene expression by fluorescent quantitative polymerase chain reaction and an analysis of enzymatic activity and GSH concentration by controlled biochemical reactions and spectrophotometry.

    GPX-4 activity but not mRNA expression is directly related to sperm morphology (strict criteria) and is more compromised with a low percentage of normal sperm. These differences are also demonstrated when fertile and infertile men were compared. In addition, intracellular GSH concentrations are lower when sperm morphology is severely impaired, but no differences were found between fertile and infertile men.

    Intracellular sperm GSH system components GPX-4 and GSH are altered in infertile men, and these alterations seem to be linked to sperm morphology.

    Fertility and sterility 2004;82 Suppl 3;1059-66

  • Role of mitochondrial phospholipid hydroperoxide glutathione peroxidase (PHGPx) as an antiapoptotic factor.

    Nakagawa Y

    School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan. nakagaway@pharm.kitasato-u.ac.jp

    Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a unique antioxidant enzyme that markedly reduces lipid hydroperoxide generated in biomembranes. Overexpression of mitochondrial PHGPx potentially suppresses the release of cytochrome c (cyt. c) from mitochondria and apoptosis. The hydroperoxide level in mitochondria was elevated in 2-deoxyglucose (2DG)-induced apoptosis, but not in apoptosis-resistant cells in which mitochondrial PHGPx was overexpressed. From studies of the overexpression of PHGPx, the generation of hydrogen peroxide and lipid hydroperoxide in mitochondria might be important triggers of apoptosis. In particular lipid hydroperoxide could be involved in the initiation of cyt. c liberation from mitochondria in 2DG-induced apoptosis since lipid hydroperoxide is a primary substrate for PHGPx. The release of cyt. c from mitochondria is an important proapoptotic signal in the mitochondrial death pathway. Several reports demonstrated the reactive oxgen species could be involved in cyt. c liberation, although its mechanism is still unknown. Cardiolipin (CL), which exclusively locates in the innermembrane of mitochondria, shows strong affinity for cyt. c is required for the adenine nucleotide translocator (ANT) that controls the opening and closing of the permeability transition pore. Association of cyt. c with CL is lost upon peroxidation. CL hydroperoxide (CLOOH), in contrast to CL, does not bind to cyt. c. Furthermore, CLOOH can open the permeability transion pore by the inactivation of ANT. These previous results suggest that mitochondrial PHGPx inhibits the release of cyt. c from mitochondria by the scavenging CLOOH and could prevent apoptosis.

    Biological & pharmaceutical bulletin 2004;27;7;956-60

  • The DNA sequence and biology of human chromosome 19.

    Grimwood J, Gordon LA, Olsen A, Terry A, Schmutz J, Lamerdin J, Hellsten U, Goodstein D, Couronne O, Tran-Gyamfi M, Aerts A, Altherr M, Ashworth L, Bajorek E, Black S, Branscomb E, Caenepeel S, Carrano A, Caoile C, Chan YM, Christensen M, Cleland CA, Copeland A, Dalin E, Dehal P, Denys M, Detter JC, Escobar J, Flowers D, Fotopulos D, Garcia C, Georgescu AM, Glavina T, Gomez M, Gonzales E, Groza M, Hammon N, Hawkins T, Haydu L, Ho I, Huang W, Israni S, Jett J, Kadner K, Kimball H, Kobayashi A, Larionov V, Leem SH, Lopez F, Lou Y, Lowry S, Malfatti S, Martinez D, McCready P, Medina C, Morgan J, Nelson K, Nolan M, Ovcharenko I, Pitluck S, Pollard M, Popkie AP, Predki P, Quan G, Ramirez L, Rash S, Retterer J, Rodriguez A, Rogers S, Salamov A, Salazar A, She X, Smith D, Slezak T, Solovyev V, Thayer N, Tice H, Tsai M, Ustaszewska A, Vo N, Wagner M, Wheeler J, Wu K, Xie G, Yang J, Dubchak I, Furey TS, DeJong P, Dickson M, Gordon D, Eichler EE, Pennacchio LA, Richardson P, Stubbs L, Rokhsar DS, Myers RM, Rubin EM and Lucas SM

    Stanford Human Genome Center, Department of Genetics, Stanford University School of Medicine, 975 California Avenue, Palo Alto, California 94304, USA. jane@shgc.stanford.edu

    Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high G + C content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in mendelian disorders, including familial hypercholesterolaemia and insulin-resistant diabetes. Nearly one-quarter of these genes belong to tandemly arranged families, encompassing more than 25% of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, and segments of coding and non-coding conservation with the distant fish species Takifugu.

    Nature 2004;428;6982;529-35

  • Native specific activity of glutathione peroxidase (GPx-1), phospholipid hydroperoxide glutathione peroxidase (PHGPx) and glutathione reductase (GR) does not differ between normo- and hypomotile human sperm samples.

    Tramer F, Caponecchia L, Sgrò P, Martinelli M, Sandri G, Panfili E, Lenzi A and Gandini L

    Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Italy.

    Glutathione-dependent selenoenzymes in human spermatozoa are responsible for a generalized protection against reactive oxygen species (ROS) as well as some other metabolic and structural regulation during spermiogenesis and sperm cell maturation. Glutathione peroxidase (GPx-1), phospholipid hydroperoxide glutathione peroxidase (GPx-4 or PHGPx) and glutathione reductase (GR) native specific activities have been studied in human Percoll-purified spermatozoa from healthy fertile subjects and asthenozoospermic patients. The mean values obtained for the three enzymes in normal specimens are 1.52 +/- 0.90 mU/10(6) sperm cells (PHGPx), 4.26 +/- 1.73 mU/10(6) sperm cells (GPx-1) and 1.95 mU/10(6) sperm cells (GR). No statistically significant differences for any of the three enzymes were encountered between these values and those of asthenozoospermic patients. These results are discussed and compared with recent literature data on both rescued and native PHGPx specific activity in human spermatozoa, as well as with data obtained for GPx in human seminal plasma.

    International journal of andrology 2004;27;2;88-93

  • Regulation of selenoprotein GPx4 expression and activity in human endothelial cells by fatty acids, cytokines and antioxidants.

    Sneddon AA, Wu HC, Farquharson A, Grant I, Arthur JR, Rotondo D, Choe SN and Wahle KW

    Lipid and Redox Regulation Group, Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK.

    Phospholipid hydroperoxide glutathione peroxidase (GPx4) is the only antioxidant enzyme known to directly reduce phospholipid hydroperoxides within membranes and lipoproteins, acting in conjunction with alpha-tocopherol to inhibit lipid peroxidation. Peroxidation of lipids has been implicated in a number of pathophysiological processes, including inflammation and atherogenesis. We investigated the relative positive and negative effects of specific polyunsaturated fatty acids (PUFAs) and inflammatory cytokines on the activity and gene expression of the selenium-dependant redox enzyme GPx4. In human umbilical vein endothelial cells (HUVEC), GPx4 mRNA levels and activity were increased optimally by 114 nM selenium (as sodium selenite). Docosahexaenoic acid (DHA) and conjugated linoleic acid (CLA) further increased mRNA levels whereas arachidonic acid (ARA) had no effect; enzyme activity was decreased by DHA, was unaffected by CLA or was increased by ARA. GPx4 protein levels increased with selenium, ARA and DHA addition but not with CLA. Interleukin-1beta (IL-1beta) increased GPx4 mRNA, protein and activity whereas TNFalpha at 1 ng/ml increased activity while at 3 ng/ml it reduced activity and mRNA. Conversely, alpha-tocopherol reduced mRNA levels without affecting activity. These results indicate that lipids, cytokines and antioxidants modulate GPx4 in a complex manner that in the presence of adequate selenium, may favour protection against potentially proatherogenic processes.

    Atherosclerosis 2003;171;1;57-65

  • Depletion of phospholipid hydroperoxide glutathione peroxidase up-regulates arachidonate metabolism by 12S-lipoxygenase and cyclooxygenase 1 in human epidermoid carcinoma A431 cells.

    Chen CJ, Huang HS and Chang WC

    Department of Pharmacology, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan 704, Taiwan.

    Phospholipid hydroperoxide glutathione peroxidase (PHGPx), a selenium-dependent glutathione peroxidase, can interact with lipophilic substrates, including the phospholipid hydroperoxides, fatty-acid hydroperoxides, and cholesteryl ester hydroperoxides, and reduce them to hydroxide compounds. We studied the functional role of endogenous PHGPx in regulation of 12(S)-lipoxygenase and cyclooxygenase 1 activities in human epidermoid carcinoma A431 cells by using a cell system overexpressing anti-PHGPx mRNA. A retroviral expression vector designated as L1-3, wherein cDNA of PHGPx was reversely inserted into pFB-ERV in antisense orientation, was constructed. A number of stable transfectants of A431 cells with PHGPx depletion were generated from virions containing plasmid L1-3. In an intact cell assay system, the metabolism of arachidonic acid to prostaglandin E2 and 12(S)-hydroxyeicosatetraenoic acid was significantly enhanced in stable L1-3 transfectants compared with that in vector-control cells. Flow cytometric analysis revealed a significant elevated level of intracellular hydroperoxides in stable L1-3 transfectants. Treatment of stable L1-3 transfectants with 50 microM arsenite induced more significant formation of intracellular hydroperoxides than that of vector-control cells. Taken together, these results support the notion that the endogenous PHGPx plays a pivotal role in the regulation of 12(S)-lipoxygenase and cyclooxygenase 1 activities by reducing the level of intracellular lipid hydroperoxides in arachidonate metabolism in A431 cells.

    FASEB journal : official publication of the Federation of American Societies for Experimental Biology 2003;17;12;1694-6

  • Phospholipid hydroperoxide glutathione peroxidase induces a delay in G1 of the cell cycle.

    Wang HP, Schafer FQ, Goswami PC, Oberley LW and Buettner GR

    Free Radical and Radiation Biology and The Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, IA 52242-1101, USA.

    Phospholipid hydroperoxide glutathione peroxidase (PhGPx) is an antioxidant enzyme that reduces cellular phospholipid hydroperoxides (PLOOHs) to alcohols. Cellular peroxide tone has been implicated in cell growth and differentiation. By reducing the PLOOH level in the cell membrane, PhGPx regulates the peroxide tone and thereby might be involved in cell growth. We hypothesized that overexpression of PhGPx in human breast cancer cells would decrease their growth rate. We stably transfected MCF-7 cells (Wt) with L-PhGPx and measured cell doubling time, plating efficiency, and cell cycle phase transit times. P-4 cells (8-fold increase in PhGPx activity) showed a 2-fold increase in doubling time; doubling time increased directly with PhGPx activity (r = 0.95). The higher the PhGPx activity, the lower the plating efficiency (r = -0.86). The profile of other antioxidant enzymes was unchanged. Overexpression of PhGPx lowered the steady-state level of PLOOH (by > 60%). Results from bromodeoxyuridine pulse-chase experiments and flow cytometry indicate that PhGPx induced a delay in MCF-7 proliferation that was primarily due to a slower progression from G1 to S. These results support the hypothesis that PhGPx plays a regulatory role in the progression of MCF-7 cells from G1 to S possibly by regulating the steady-state levels of PLOOH. These data suggest that PhGPx can lower the peroxide tone, which might change the cellular redox environment resulting in a delay in G1 transit. Thus, PhGPx could be an important factor in cell growth.

    Funded by: NCI NIH HHS: CA66081, CA69593, CA81090, P01 CA066081, R01 CA084462

    Free radical research 2003;37;6;621-30

  • A study to survey susceptible genetic factors responsible for troglitazone-associated hepatotoxicity in Japanese patients with type 2 diabetes mellitus.

    Watanabe I, Tomita A, Shimizu M, Sugawara M, Yasumo H, Koishi R, Takahashi T, Miyoshi K, Nakamura K, Izumi T, Matsushita Y, Furukawa H, Haruyama H and Koga T

    Regulatory Affairs Department, Sankyo Co, Ltd, Tokyo, Japan.

    Troglitazone is a 2,4-thiazolidinedione antidiabetic agent with insulin-sensitizing activities. This agent had been used efficiently in a large number of patients but was withdrawn from the market in March 2000 because of its association with idiosyncratic hepatotoxicity. To address the susceptible genetic factors responsible for the hepatotoxicity associated with this agent, we performed a genetic polymorphic analysis by a target gene approach in troglitazone-treated Japanese patients with type 2 diabetes mellitus.

    Methods: One hundred ten patients treated with troglitazone were recruited into this study. The case patients (n = 25) were recruited through medical professionals who had previously reported abnormal increases in the levels of ALT or AST among their patients. The control patients (n = 85) were recruited through physicians prescribing troglitazone. For statistical accuracy, efforts were made to maximize the size of the case group. Genotype analysis was performed in 68 polymorphic sites of 51 candidate genes related to drug metabolism, apoptosis, roduction and elimination of reactive oxygen species, and signal transduction pathways of peroxisome proliferator-activated receptor gamma 2 and insulin.

    Results: The strong correlation with transaminase elevations was observed in the combined glutathione-S-transferase GSTT1-GSTM1 null genotype (odds ratio, 3.692; 95% confidence interval, 1.354-10.066; P =.008).

    Conclusions: The double null mutation of GSTT1 and GSTM1 might influence troglitazone-associated abnormal increases of liver enzyme levels.

    Clinical pharmacology and therapeutics 2003;73;5;435-55

  • Genetic variations of gpx-4 and male infertility in humans.

    Maiorino M, Bosello V, Ursini F, Foresta C, Garolla A, Scapin M, Sztajer H and Flohe L

    Department of Biological Chemistry, University of Padova, I-35121 Padova, Italy. mmaior@mail.bio.unipd.it

    Phospholipid hydroperoxide glutathione peroxidase (PHGPx), the product of gpx-4, is the major selenoprotein in sperm and is considered essential for fertilization because of its multiple roles in spermatogenesis, such as hydroperoxide detoxification, formation of the mitochondrial capsule, and chromatin condensation. Genomic DNA sequences of 3.148 kilobases covering the whole gpx-4 and its flanking regions were amplified from 63 men using the polymerase chain reaction and were analyzed for polymorphisms by direct sequencing. A total of 23 variant sites were detected; 2 were present only in control men (proven fathers; n = 21) and 10 were common to fertile controls and infertile patients (n = 42). A further 11 variant sites were seen in five of the infertile men only. Four of the gpx-4 variants were considered irrelevant to GPx-4-related fertility problems because they occurred homozygously in controls. The majority of the remaining variant sites are also of questionable relevance because they are located in introns or, as third base exchanges, do not affect the protein sequence. However, one of the exon variations leads to an Ala93-Thr exchange that reduces activity in a porcine GPx-4 homologue. Two detected promoter variations were shown by reporter gene constructs to affect transcription in somatic cell lines. These results indicate that gpx-4 polymorphism cannot generally account for the correlation of PHGPx content of sperm and fertility-related parameters, but further examination of this gene as a potential cause of infertility in particular cases is warranted.

    Biology of reproduction 2003;68;4;1134-41

  • Regulation of expression of the phospholipid hydroperoxide/sperm nucleus glutathione peroxidase gene. Tissue-specific expression pattern and identification of functional cis- and trans-regulatory elements.

    Borchert A, Savaskan NE and Kuhn H

    Institute of Biochemistry, Humboldt University Medical School Charité, Monbijoustrasse 2, 10117 Berlin, Germany.

    A sperm nucleus glutathione peroxidase (snGPx), which is closely related to the phospholipid hydroperoxide glutathione peroxidase (phGPx), was recently discovered in late spermatids. Both GPx isoforms originate from a joint ph/snGPx gene, but their N-terminal peptides are encoded by alternative first exons. The expression of the two enzymes is differentially regulated in various cells, but little is known about the regulatory mechanisms. To explore the tissue-specific regulation of expression of the two isoenzymes, we first investigated their tissue distribution. Whereas phGPx is expressed at low levels in many organs, snGPx was only detected in testis, kidney, and in the human embryonic kidney cell line HEK293. Subcellular fractionation studies and immunoelectron microscopy revealed a cytosolic localization. To explore the mechanistic reasons for the differential expression pattern, we first tested the activity of the putative phGPx and snGPx promoters. The 5'-flanking region of the joint ph/snGPx gene exhibits strong promoter activity. In contrast, the putative snGPx promoter, which comprises 334 bp of intronic sequences, lacks major promoter activity. However, it strongly suppresses the activity of the ph/snGPx promoter. These data suggest negative regulatory elements in the first intron of the ph/snGPx gene, and DNase protection assays revealed the existence of several protein-binding sites. The corresponding trans-regulatory proteins (SP1, ERG1, GATA1, SREBP1, USF1, and CREBP1) were identified, and in vivo binding of EGR1 and SREBP1 was shown by chromatin immunoprecipitation. These data indicate for the first time somatic expression of the snGPx and provide evidence for the existence of intronic negative cis-regulatory elements in the ph/snGPx gene. Our failure to detect an alternative snGPx promoter suggests that transcription of the ph/snGPx gene may be regulated by a joint basic promoter. The decision, which GPx isoform is expressed in a given cell, appears to be made by alternative splicing of a joint primary transcript.

    The Journal of biological chemistry 2003;278;4;2571-80

  • A novel single nucleotide polymorphism in the 3' untranslated region of human glutathione peroxidase 4 influences lipoxygenase metabolism.

    Villette S, Kyle JA, Brown KM, Pickard K, Milne JS, Nicol F, Arthur JR and Hesketh JE

    Department of Biological and Nutritional Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU United Kingdom.

    Selenium (Se) is an essential micronutrient for human health. The biological roles of the essential micronutrient Se are attributed to its presence in a range of 20-30 selenoproteins including the cytosolic and phospholipid hydroperoxide glutathione peroxidases (GPX1 and GPX4). It has been suggested that GPX4 may play a role in regulation of leukotriene biosynthesis and thus inflammation. In eukaryotes Se is incorporated into selenoproteins as the amino acid selenocysteine in a process requiring a stem-loop within the 3' untranslated region (3'UTR) of the mRNA. In this study the region of the GPX4 gene corresponding to the 3'UTR was scanned for mutations in a group of 66 volunteers. The data show a T/C variant at position 718. The distribution of this SNP in our population was 34% CC, 25% TT and 41% TC; i.e., it is in Hardy-Weinberg equilibrium. Individuals of different genotypes exhibited significant differences in the levels of lymphocyte 5-lipoxygenase total products, with C718 showing increased levels of those products compared to T718 and T/C718 (36% and 44% increases, respectively). The data suggest that the SNP718 that we have identified has functional effects and support the hypothesis that GPX4 plays a regulatory role in leukotriene biosynthesis.

    Blood cells, molecules & diseases 2002;29;2;174-8

  • Male fertility is linked to the selenoprotein phospholipid hydroperoxide glutathione peroxidase.

    Foresta C, Flohé L, Garolla A, Roveri A, Ursini F and Maiorino M

    Department of Medical and Surgical Sciences, Clinica Medica 3, University of Padova, I-35128 Padova, Italy.

    The selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) accounts for almost the entire selenium content of mammalian testis. PHGPx is abundantly expressed in spermatids as active peroxidase but is transformed to an oxidatively inactivated protein in mature sperm, where it is a major constituent of the mitochondrial capsule in the midpiece. Male infertility in selenium-deficient animals, which is characterized by impaired sperm motility and morphological midpiece alterations, is considered to result from insufficient PHGPx content. We studied the relationship between sperm PHGPx, measured as rescued activity, and human fertility. Sperm specimens from 75 infertile men and 37 controls were analyzed for fertility-related parameters according to World Health Organization criteria. The PHGPx protein content was estimated after reductive solubilization of the spermatozoa by measuring the rescued PHGPx activity. Rescued PHGPx activity of infertile men ranged significantly below that of controls (93.2 +/- 60.1 units/mg sperm protein vs. 187.5 +/- 55.3 units/mg) and was particularly low in oligoasthenozoospermic specimens (61.93 +/- 45.42 units/mg; P < 0.001 compared with controls and asthenozoospermic samples). Rescued PHGPx activity was correlated positively with viability, morphological integrity, and most profoundly forward motility (r = 0.35, 0.44, and 0.45, respectively). In isolated motile samples, motility decreased faster with decreasing PHGPx content. In humans, PHGPx appears to be indispensable for structural integrity of spermatozoa and to codetermine sperm motility and viability. Because the content of PHGPx, irrespective of the cause of alteration, is correlated with fertility-related parameters, PHGPx can be considered a predictive measure for fertilization capacity.

    Biology of reproduction 2002;67;3;967-71

  • Expression of human phospholipid hydroperoxide glutathione peroxidase.

    Yagi K, Komura S and Ohishi N

    Institute of Applied Biochemistry, Yagi Memorial Park, Mitake, Japan.

    Methods in molecular biology (Clifton, N.J.) 2002;196;195-9

  • Human immunodeficiency virus type 1 Tat protein impairs selenoglutathione peroxidase expression and activity by a mechanism independent of cellular selenium uptake: consequences on cellular resistance to UV-A radiation.

    Richard MJ, Guiraud P, Didier C, Seve M, Flores SC and Favier A

    LBSO/LCR7 No. 8, Université Joseph Fourier, Grenoble, France. Marie-Jeanne.Richard@ujf-grenoble.fr

    The expression of the HIV-1 Tat protein in HeLa cells resulted in a 2.5-fold decrease in the activity of the antioxidant enzyme glutathione peroxidase (GPX). This decrease seemed not to be due to a disturbance in selenium (Se) uptake. Indeed, the intracellular level of Se was similar in parental and tat-transfected cells. A Se enrichment of the medium did not lead to an identical GPX activity in both cell lines, suggesting a disturbance in Se utilization. Total intracellular 75Se selenoproteins were analyzed. Several quantitative differences were observed between parental and tat-transfected cells. Mainly, cytoplasmic glutathione peroxidase and a 15-kDa selenoprotein were decreased in HeLa-tat cells, while phospholipid hydroperoxide glutathione peroxidase and low-molecular-mass selenocompounds were increased. Thioredoxin reductase activity and total levels of 75Se-labeled proteins were not different between the two cell types. The effect of Tat on GPX mRNA levels was also analyzed. Northern blots revealed a threefold decrease in the GPX/glyceraldehyde phosphate dehydrogenase mRNA ratio in HeLa-tat versus wild type cells. By deregulating the intracellular oxidant/antioxidant balance, the Tat protein amplified UV sensitivity. The LD50 for ultraviolet radiation A was 90 J/cm2 for HeLa cells and only 65 J/cm2 for HeLa-tat cells. The oxidative stress occurring in the Tat-expressing cells and demonstrated by the diminished ratio of reduced glutathione/oxidized glutathione was not correlated with the intracellular metal content. Cellular iron and copper levels were significantly decreased in HeLa-tat cells. All these disturbances, as well as the previously described decrease in Mn superoxide dismutase activity, are part of the viral strategy to modify the redox potential of cells and may have important consequences for patients.

    Archives of biochemistry and biophysics 2001;386;2;213-20

  • Molecular mechanism of decreased glutathione content in human immunodeficiency virus type 1 Tat-transgenic mice.

    Choi J, Liu RM, Kundu RK, Sangiorgi F, Wu W, Maxson R and Forman HJ

    Department of Molecular Pharmacology, University of Southern California School of Pharmacy, Los Angeles, California 90033, USA.

    Human immunodeficiency virus (HIV) progressively depletes GSH content in humans. Although the accumulated evidence suggests a role of decreased GSH in the pathogenesis of HIV, significant controversy remains concerning the mechanism of GSH depletion, especially in regard to envisioning appropriate therapeutic strategies to help compensate for such decreased antioxidant capacity. Tat, a transactivator encoded by HIV, is sufficient to cause GSH depletion in vitro and is implicated in AIDS-associated Kaposi's sarcoma and B cell lymphoma. In this study, we report a decrease in GSH biosynthesis with Tat, using HIV-1 Tat transgenic (Tat+) mice. A significant decline in the total intracellular GSH content in liver and erythrocytes of Tat+ mice was accompanied by decreased gamma-glutamylcysteine synthetase regulatory subunit mRNA and protein content, which resulted in an increased sensitivity of gamma-glutamylcysteine synthetase to feedback inhibition by GSH. Further study revealed a significant reduction in the activity of GSH synthetase in liver of Tat+ mice, which was linearly associated with their GSH content. Therefore, Tat appears to decrease GSH in vivo, at least partially, through modulation of GSH biosynthetic enzymes.

    Funded by: NIEHS NIH HHS: ES05511

    The Journal of biological chemistry 2000;275;5;3693-8

  • Dual function of the selenoprotein PHGPx during sperm maturation.

    Ursini F, Heim S, Kiess M, Maiorino M, Roveri A, Wissing J and Flohé L

    Dipartmento di Chimica Biologica, Università di Padova, Viale G. Colombo 3, I-35121 Padova, Italy.

    The selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) changes its physical characteristics and biological functions during sperm maturation. PHGPx exists as a soluble peroxidase in spermatids but persists in mature spermatozoa as an enzymatically inactive, oxidatively cross-linked, insoluble protein. In the midpiece of mature spermatozoa, PHGPx protein represents at least 50 percent of the capsule material that embeds the helix of mitochondria. The role of PHGPx as a structural protein may explain the mechanical instability of the mitochondrial midpiece that is observed in selenium deficiency.

    Science (New York, N.Y.) 1999;285;5432;1393-6

  • Structural organization of the human selenium-dependent phospholipid hydroperoxide glutathione peroxidase gene (GPX4): chromosomal localization to 19p13.3.

    Kelner MJ and Montoya MA

    Department of Pathology, University of California, San Diego 92103-8320, USA. mkelner@ucsd.edu

    The primary structure of human selenium-dependent phospholipid hydroperoxide glutathione peroxidase (GPX4) was determined by genomic cloning. The gene structure of GPX4 spans only 2.8 kb and consists of 7 exons. The coding sequence resides on all 7 exons, and the mitochondrial leader sequence is contained entirely within the first exon. The selenocysteine coding nucleotide resides on the third exon. The introns all commenced with the consensus nucleotide sequence GTR and ended with the consensus nucleotide sequence YAG. Analysis of the GPX4 gene sequence identified a potential alternative tissue-specific first exon. Chromosomal FISH studies placed the GPX4 gene at 19p13.3 location, and downstream of the 23 k-Da polypeptide DNA-directed RNA polymerase gene.

    Funded by: NCI NIH HHS: CA52310

    Biochemical and biophysical research communications 1998;249;1;53-5

  • Glutathione depletion associated with the HIV-1 TAT protein mediates the extracellular appearance of acidic fibroblast growth factor.

    Opalenik SR, Ding Q, Mallery SR and Thompson JA

    Department of Surgery, School of Medicine, University of Alabama at Birmingham 35294, USA.

    Primary murine embryonic fibroblasts transfected with HIV-1 TAT demonstrated decreased levels of high energy phosphates (ATP, GTP, UTP/CTP), adenine nucleotides (ATP, ADP, AMP), and both NAD+/NADH redox pairs, resulting in a substantial loss of redox poise. A greater than 50% decrease in intracellular reduced glutathione (GSH) concentration was accompanied by the extracellular appearance of acidic fibroblast growth factor (FGF-1). Addition of either N-acetyl-L-cysteine or glutathione ester (GSE), but not L-2-oxothiazolidine 4-carboxylate, partially restored intracellular GSH levels and resulted in loss of extracellular FGF-1. Treatment of FGF-1-transduced cells with buthionine sulfoximine (BSO) resulted in a time- and dose-dependent decrease in total cellular GSH concentration that was accompanied by the extracellular appearance of FGF-1. Inclusion of GSE during BSO treatment eliminated the extracellular appearance of FGF-1. BSO treatment of cells transfected with a mutant form of FGF-1, in which all three cysteine residues were replaced with serines, also decreased total cellular GSH concentration but failed to induce the extracellular appearance of FGF-1. Collectively, these results suggest that HIV-1 TAT induces a condition of oxidative stress, which mediates cellular secretion of FGF-1, an observation relevant to the pathophysiologic development and progression of AIDS-associated Kaposi's sarcoma.

    Funded by: NHLBI NIH HHS: HL448491, HL45990, HL48457

    Archives of biochemistry and biophysics 1998;351;1;17-26

  • Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library.

    Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, Suyama A and Sugano S

    International and Interdisciplinary Studies, The University of Tokyo, Japan.

    Using 'oligo-capped' mRNA [Maruyama, K., Sugano, S., 1994. Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides. Gene 138, 171-174], whose cap structure was replaced by a synthetic oligonucleotide, we constructed two types of cDNA library. One is a 'full length-enriched cDNA library' which has a high content of full-length cDNA clones and the other is a '5'-end-enriched cDNA library', which has a high content of cDNA clones with their mRNA start sites. The 5'-end-enriched library was constructed especially for isolating the mRNA start sites of long mRNAs. In order to characterize these libraries, we performed one-pass sequencing of randomly selected cDNA clones from both libraries (84 clones for the full length-enriched cDNA library and 159 clones for the 5'-end-enriched cDNA library). The cDNA clones of the polypeptide chain elongation factor 1 alpha were most frequently (nine clones) isolated, and more than 80% of them (eight clones) contained the mRNA start site of the gene. Furthermore, about 80% of the cDNA clones of both libraries whose sequence matched with known genes had the known 5' ends or sequences upstream of the known 5' ends (28 out of 35 for the full length-enriched library and 51 out of 62 for the 5'-end-enriched library). The longest full-length clone of the full length-enriched cDNA library was about 3300 bp (among 28 clones). In contrast, seven clones (out of the 51 clones with the mRNA start sites) from the 5'-end-enriched cDNA library came from mRNAs whose length is more than 3500 bp. These cDNA libraries may be useful for generating 5' ESTs with the information of the mRNA start sites that are now scarce in the EST database.

    Gene 1997;200;1-2;149-56

  • Cloning and sequencing of the cDNA encoding a human testis phospholipid hydroperoxide glutathione peroxidase.

    Esworthy RS, Doan K, Doroshow JH and Chu FF

    Department of Medical Oncology, City of Hope National Medical Center, Duarte, CA 9101.

    A human cDNA that encodes a polypeptide that has 94% deduced amino-acid sequence identity to porcine phospholipid hydroperoxide glutathione peroxidase was cloned from a testis library. The sequence shows preservation of the UGA selenocysteine codon, putative active-site Trp and Glu residues and a Tyr residue that is phosphorylated in the porcine protein. The 3'-UTR shows some conservation of sequences implicated in the insertion of selenocysteine at an opal codon in human glutathione peroxidase-1.

    Funded by: NCI NIH HHS: CA33572; NIDDK NIH HHS: DK 46921

    Gene 1994;144;2;317-8

  • Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides.

    Maruyama K and Sugano S

    Institute of Medical Science, University of Tokyo, Japan.

    We have devised a method to replace the cap structure of a mRNA with an oligoribonucleotide (r-oligo) to label the 5' end of eukaryotic mRNAs. The method consists of removing the cap with tobacco acid pyrophosphatase (TAP) and ligating r-oligos to decapped mRNAs with T4 RNA ligase. This reaction was made cap-specific by removing 5'-phosphates of non-capped RNAs with alkaline phosphatase prior to TAP treatment. Unlike the conventional methods that label the 5' end of cDNAs, this method specifically labels the capped end of the mRNAs with a synthetic r-oligo prior to first-strand cDNA synthesis. The 5' end of the mRNA was identified quite simply by reverse transcription-polymerase chain reaction (RT-PCR).

    Gene 1994;138;1-2;171-4

  • The human glutathione peroxidase genes GPX2, GPX3, and GPX4 map to chromosomes 14, 5, and 19, respectively.

    Chu FF

    Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010-0269.

    cDNA probes of human glutathione peroxidase (GSHPx) genes, including the classic GPX1 (GSHPx-1), the newly characterized GPX2 (GSHPx-GI), the plasma enzyme GPX3 (GSHPx-P), and the phospholipid hydroperoxide glutathione peroxidase GPX4 (PHGPX), were hybridized to Southern blots containing genomic DNA from human x hamster somatic cell hybrids. GPX2 was mapped to chromosome 14, GPX3 to chromosome 5 and GPX4 to chromosome 19. Additionally, human chromosomes 3 and 21 and the X chromosome were shown to contain sequences homologous to GPX1, as reported previously.

    Funded by: NCI NIH HHS: CA-33572; NIDDK NIH HHS: 1-R29-DK46921

    Cytogenetics and cell genetics 1994;66;2;96-8

Gene lists (5)

Gene List Source Species Name Description Gene count
L00000009 G2C Homo sapiens Human PSD Human orthologues of mouse PSD adapted from Collins et al (2006) 1080
L00000016 G2C Homo sapiens Human PSP Human orthologues of mouse PSP adapted from Collins et al (2006) 1121
L00000049 G2C Homo sapiens TAP-PSD-95-CORE TAP-PSD-95 pull-down core list (ortho) 120
L00000069 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-FULL Human cortex biopsy PSD full list 1461
L00000071 G2C Homo sapiens BAYES-COLLINS-MOUSE-PSD-FULL Mouse cortex PSD full list (ortho) 1556
© G2C 2014. The Genes to Cognition Programme received funding from The Wellcome Trust and the EU FP7 Framework Programmes:
EUROSPIN (FP7-HEALTH-241498), SynSys (FP7-HEALTH-242167) and GENCODYS (FP7-HEALTH-241995).

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