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Pálešová N, Bláhová L, Janoš T, Řiháčková K, Pindur A, Šebejová L, Čupr P. Exposure to benzotriazoles and benzothiazoles in Czech male population and its associations with biomarkers of liver function, serum lipids and oxidative stress. Int Arch Occup Environ Health 2024; 97:523-536. [PMID: 38546760 PMCID: PMC11130049 DOI: 10.1007/s00420-024-02059-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/22/2024] [Indexed: 05/28/2024]
Abstract
INTRODUCTION Benzotriazoles and benzothiazoles (BTs) are high-production volume chemicals as well as widely distributed emerging pollutants with potential health risk. However, information about human exposure to BTs and associated health outcomes is limited. OBJECTIVE We aimed to characterise exposure to BTs among Czech men, including possible occupational exposure among firefighters, its predictors, and its associations with liver function, serum lipids and oxidative stress. METHODS 165 participants (including 110 firefighters) provided urine and blood samples that were used to quantify the urinary levels of 8 BTs (high-performance liquid chromatography-tandem mass spectrometry), and 4 liver enzymes, cholesterol, low-density lipoprotein, and 8-hydroxy-2'-deoxyguanosine. Linear regression was used to assess associations with population characteristics and biomarkers of liver function, serum lipids and oxidative stress. Regression models were adjusted for potential confounding variables and false discovery rate procedure was applied to account for multiplicity. RESULTS The BTs ranged from undetected up to 46.8 ng/mL. 2-hydroxy-benzothiazole was the most predominant compound (detection frequency 83%; median 1.95 ng/mL). 1-methyl-benzotriazole (1M-BTR) was measured in human samples for the first time, with a detection frequency 77% and median 1.75 ng/mL. Professional firefighters had lower urinary 1M-BTR compared to non-firefighters. Urinary 1M-BTR was associated with levels of γ-glutamyl transferase (β = - 17.54%; 95% CI: - 26.127, - 7.962). CONCLUSION This is the first study to investigate BT exposure in Central Europe, including potentially exposed firefighters. The findings showed a high prevalence of BTs in the study population, the relevance of 1M-BTR as a new biomarker of exposure, and an urgent need for further research into associated adverse health outcomes.
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Affiliation(s)
- Nina Pálešová
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic
| | - Lucie Bláhová
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic
| | - Tomáš Janoš
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic
| | - Katarína Řiháčková
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic
| | - Aleš Pindur
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic
- Faculty of Sports Studies, Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic
- Training Centre of Fire Rescue Service, General Directorate of Fire Rescue Service of the Czech Republic, Ministry of the Interior, Trnkova 85, 628 00, Brno, Czech Republic
| | - Ludmila Šebejová
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic
| | - Pavel Čupr
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic.
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Zhang T, Yao C, Zhou X, Liu S, Qi L, Zhu S, Zhao C, Hu D, Shen W. Glutathione‑degrading enzymes in the complex landscape of tumors (Review). Int J Oncol 2024; 65:72. [PMID: 38847236 PMCID: PMC11173371 DOI: 10.3892/ijo.2024.5660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/24/2024] [Indexed: 06/12/2024] Open
Abstract
Glutathione (GSH)‑degrading enzymes are essential for starting the first stages of GSH degradation. These enzymes include extracellular γ‑glutamyl transpeptidase (GGT) and intracellular GSH‑specific γ‑glutamylcyclotransferase 1 (ChaC1) and 2. These enzymes are essential for cellular activities, such as immune response, differentiation, proliferation, homeostasis regulation and programmed cell death. Tumor tissue frequently exhibits abnormal expression of GSH‑degrading enzymes, which has a key impact on the development and spread of malignancies. The present review summarizes gene and protein structure, catalytic activity and regulation of GSH‑degrading enzymes, their vital roles in tumor development (including regulation of oxidative and endoplasmic reticulum stress, control of programmed cell death, promotion of inflammation and tumorigenesis and modulation of drug resistance in tumor cells) and potential role as diagnostic biomarkers and therapeutic targets.
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Affiliation(s)
- Tianyi Zhang
- Department of Acupuncture, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Chongjie Yao
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
- Department of Rehabilitation, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Xu Zhou
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Shimin Liu
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
- Shanghai Research Institute of Acupuncture and Meridian, Shanghai 200030, P.R. China
| | - Li Qi
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Shiguo Zhu
- School of Basic Medical Sciences, Center for Traditional Chinese Medicine and Immunology Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Chen Zhao
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Dan Hu
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Weidong Shen
- Department of Acupuncture, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
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Mitrić A, Castellano I. Targeting gamma-glutamyl transpeptidase: A pleiotropic enzyme involved in glutathione metabolism and in the control of redox homeostasis. Free Radic Biol Med 2023; 208:672-683. [PMID: 37739139 DOI: 10.1016/j.freeradbiomed.2023.09.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/07/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023]
Abstract
Gamma-glutamyl transpeptidase (GGT) is an enzyme located on the outer membrane of the cells where it regulates the metabolism of glutathione (GSH), the most abundant intracellular antioxidant thiol. GGT plays a key role in the control of redox homeostasis, by hydrolyzing extracellular GSH and providing the cell with the recovery of cysteine, which is necessary for de novo intracellular GSH and protein biosynthesis. Therefore, the upregulation of GGT confers to the cell greater resistance to oxidative stress and the advantage of growing fast. Indeed, GGT is upregulated in inflammatory conditions and in the progression of various human tumors and it is involved in many physiological disorders related to oxidative stress, such as cardiovascular disease and diabetes. Currently, increased GGT expression is considered a marker of liver damage, cancer, and low-grade chronic inflammation. This review addresses the current knowledge on the structure-function relationship of GGT, focusing on human GGT, and provides information on the pleiotropic biological role and relevance of the enzyme as a target of drugs aimed at alleviating oxidative stress-related diseases. The development of new GGT inhibitors is critically discussed, as are the advantages and disadvantages of their potential use in clinics. Considering its pleiotropic activities and evolved functions, GGT is a potential "moonlighting protein".
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Affiliation(s)
- Aleksandra Mitrić
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Immacolata Castellano
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131, Naples, Italy; Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, Italy.
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Zheng Y, Guan J, Wang L, Luo X, Zhang X. Comparative proteomic analysis of spleen reveals key immune-related proteins in the yak (Bos grunniens) at different growth stages. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2022; 42:100968. [PMID: 35150973 DOI: 10.1016/j.cbd.2022.100968] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 11/30/2022]
Abstract
Spleen plays an indispensable role in the immune system as the largest lymphatic organ in the body. The spleens of yaks at three developmental stages (1 day fetal yak, 15 months juvenile yak and 5 years old adult yak) were sampled and the Tandem mass tag (TMT) quantification method was employed in spleen proteomic analysis. The results showed that 6576 proteins and 529 differentially expressed proteins (DEPs) were identified in the yak spleens at three growth stages. Gene ontology (GO) analysis of DEPs indicated that DEPs were enriched in Oxygen transport, Actin filament movement, DNA replication, Cell cycle process, and Cell macromolecule biosynthesis process, which was conducive to high altitude breathing, protein synthesis and organ growth in yaks. These were indispensable for yak spleen growth and cell metabolism, high altitude adaptation. Those DEPs were further analyzed based on Kyoto encyclopedia of genes and genomes (KEGG) pathways, which principally participated in Th1 and Th2 cell differentiation, NF-kappa B signaling pathway, Phagosome, and Glutathione metabolism. Those pathways were associated with some animal life activities in defense against microbial antigens, indicating that with age, the immune function of the yak's spleen continued to increase. Hemoglobin, Tumor necrosis factor receptor associated factor 1 (TRAF1), T cell receptor (TCR), Macrophage receptor, Fc receptors (FcR), and Gamma-glutamyl transferase (GGT) of DEPs played roles in immune function in yak spleen directly or indirectly. The dynamic changes of Toll like receptor 2 (TLR2), TRAF1 and Heat shock protein 27 (HSP27 or HSPB1) detected by Immunohistochemistry were consistent with those obtained from TMT proteomic. In conclusion, this study provides extensive and functional analyses of the spleen proteome at three developmental stages and will offer a new insight into key proteins involved in the immune function of yak spleen.
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Affiliation(s)
- Yao Zheng
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China
| | - Jiuqiang Guan
- Sichuan Academy of Grassland Sciences, Chengdu 611731, China
| | - Li Wang
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Ministry of Education and Sichuan Province, Southwest Minzu University, Chengdu 610041, China.
| | - Xiaolin Luo
- Sichuan Academy of Grassland Sciences, Chengdu 611731, China.
| | - Xiangfei Zhang
- Sichuan Academy of Grassland Sciences, Chengdu 611731, China
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Robbins ME, Cho HY, Hansen JM, Luchsinger JR, Locy ML, Velten M, Kleeberger SR, Rogers LK, Tipple TE. Glutathione reductase deficiency alters lung development and hyperoxic responses in neonatal mice. Redox Biol 2021; 38:101797. [PMID: 33254076 PMCID: PMC7708869 DOI: 10.1016/j.redox.2020.101797] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/14/2022] Open
Abstract
Cellular antioxidants protect against hyperoxic lung injury. The role of the glutathione (GSH) system in lung development and bronchopulmonary dysplasia (BPD) pathogenesis has not been systematically investigated. The current study utilized GSH reductase-deficient (Gsr-KO) neonatal mice to test the hypothesis that early disruption of the GSH system negatively impacts lung development and hyperoxic responses. Lungs from wild-type (Gsr-WT) and Gsr-KO mice were analyzed for histopathology, developmental markers, redox indices, and transcriptome profiling at different developmental stages following exposure to room air or hyperoxia (85% O2) for up to 14 d. Lungs from Gsr-KO mice exhibited alveolar epithelial dysplasia in the embryonic and neonatal periods with relatively normal lung architecture in adulthood. GSH and its oxidized form (GSSG) were 50-70% lower at E19-PND14 in Gsr-KO lungs than in age-matched Gsr-WT. Differential gene expression between Gsr-WT and Gsr-KO lungs was analyzed at discrete developmental stages. Gsr-KO lungs exhibited downregulated cell cycle and DNA damage checkpoint genes at E19, as well as lung lipid metabolism and surfactant genes at PND5. In addition to abnormal baseline lung morphometry, Gsr-KO mice displayed a blunted response to hyperoxia. Hyperoxia caused a more robust upregulation of the lung thioredoxin system in Gsr-KO compared to Gsr-WT. Gsr-dependent, hyperoxia-responsive genes were highly associated with abnormal cytoskeleton, skeletal-muscular function, and tissue morphology at PND5. Overall, our data in Gsr-KO mice implicate the GSH system as a key regulator of lung development, cellular differentiation, and hyperoxic responses in neonatal mice.
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Affiliation(s)
- Mary E Robbins
- Division of Neonatology, Department of Pediatrics, Northwestern University, Chicago, IL, USA.
| | - Hye-Youn Cho
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Jason M Hansen
- Physiology & Developmental Biology, Brigham Young University, Provo, UT, USA
| | - Joseph R Luchsinger
- Medical Scientist Training Program, Vanderbilt University, Nashville, TN, USA
| | - Morgan L Locy
- Medical Scientist Training Program, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Markus Velten
- Department of Anesthesiology and Intensive Care Medicine, Rheinische Friedrich- Wilhelms University, University Medical Center, Bonn, Germany
| | - Steven R Kleeberger
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Lynette K Rogers
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Trent E Tipple
- Center for Pregnancy and Newborn Research, Section of Neonatal-Perinatal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Per S, Kose M, Ozdemir A, Pandir D. Hepatoprotective effects of capping protein gelsolin against hyperoxia-induced hepatotoxicity, oxidative stress and DNA damage in neonatal rats. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2018; 58:189-195. [PMID: 29408761 DOI: 10.1016/j.etap.2018.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 01/15/2018] [Accepted: 01/18/2018] [Indexed: 06/07/2023]
Abstract
Tissues and organs get exposed to high oxygen (O2) supply in hyperoxia conditions. The goal of this research was to investigate the protective effect of actin binding protein gelsolin on hyperoxia-induced hepatotoxicity through histopathology and measurement of oxidative stress parameters and DNA damage in a neonatal Wistar albino rats. The pups were randomly separated to four equal groups such as: normoxia control group (NC), normoxia plus gelsolin group (NG, 10 ng/kg bw/day gelsolin), hyperoxia (≥85% O2) group (HC), hyperoxia plus gelsolin group (HG, ≥85% O2; 10 ng/kg bw/day gelsolin). Histopathological changes of pups in hyperoxia condition were revealed in the form of severe leukocyte infiltration, vascular congestion, necrosis, vacuolar degeneration, binucleated hepatocytes and hemorrhage in the liver tissue. SOD, CAT, GPx and GST activities decreased and MDA level increased in the hyperoxia-induced group in liver tissue (P < 0.05). Tail DNA%, tail length and moment indicating DNA damage statistically increased in hyperoxia treatment groups when compared to controls. Treatment of rats with hyperoxia plus gelsolin prevented hyperoxia-induced changes in tissue structure, antioxidant enzyme activities and MDA level, mean tail DNA% and length. Based on these findings, gelsolin restored these changing to near normal levels but it does not protect completely in the hyperoxia conditions.
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Affiliation(s)
- Sedat Per
- Department of Biology, Bozok University, Yozgat, Turkey.
| | - Mehmet Kose
- Department of Pediatrics, Division of Pediatric Pulmonology Unit, Erciyes University, Kayseri, Turkey
| | - Ahmet Ozdemir
- Department of Pediatrics, Division of Neonatology, Erciyes University, Kayseri, Turkey
| | - Dilek Pandir
- Department of Biology, Bozok University, Yozgat, Turkey
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Abstract
SIGNIFICANCE Glutathione degradation has for long been thought to occur only on noncytosolic pools. This is because there has been only one enzyme known to degrade glutathione (γ-glutamyl transpeptidase) and this localizes to either the plasma membrane (mammals, bacteria) or the vacuolar membrane (yeast, plants) and acts on extracellular or vacuolar pools. The last few years have seen the discovery of several new enzymes of glutathione degradation that function in the cytosol, throwing new light on glutathione degradation. Recent Advances: The new enzymes that have been identified in the last few years that can initiate glutathione degradation include the Dug enzyme found in yeast and fungi, the ChaC1 enzyme found among higher eukaryotes, the ChaC2 enzyme found from bacteria to man, and the RipAY enzyme found in some bacteria. These enzymes play roles ranging from housekeeping functions to stress responses and are involved in processes such as embryonic neural development and pathogenesis. CRITICAL ISSUES In addition to delineating the pathways of glutathione degradation in detail, a critical issue is to find how these new enzymes impact cellular physiology and homeostasis. FUTURE DIRECTIONS Glutathione degradation plays a far greater role in cellular physiology than previously envisaged. The differential regulation and differential specificities of various enzymes, each acting on distinct pools, can lead to different consequences to the cell. It is likely that the coming years will see these downstream effects being unraveled in greater detail and will lead to a better understanding and appreciation of glutathione degradation. Antioxid. Redox Signal. 27, 1200-1216.
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Affiliation(s)
- Anand Kumar Bachhawat
- Department of Biological Sciences, Indian Institute of Science Education and Research , Mohali, Mohali, India
| | - Amandeep Kaur
- Department of Biological Sciences, Indian Institute of Science Education and Research , Mohali, Mohali, India
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Moriwaki S, Into T, Suzuki K, Miyauchi M, Takata T, Shibayama K, Niida S. γ-Glutamyltranspeptidase is an endogenous activator of Toll-like receptor 4-mediated osteoclastogenesis. Sci Rep 2016; 6:35930. [PMID: 27775020 PMCID: PMC5075938 DOI: 10.1038/srep35930] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 10/07/2016] [Indexed: 12/14/2022] Open
Abstract
Chronic inflammation-associated bone destruction, which is observed in rheumatoid arthritis (RA) and periodontitis, is mediated by excessive osteoclastogenesis. We showed previously that γ-glutamyltranspeptidase (GGT), an enzyme involved in glutathione metabolism, acts as an endogenous activator of such pathological osteoclastogenesis, independent of its enzymatic activity. GGT accumulation is clinically observed in the joints of RA patients, and, in animals, the administration of recombinant GGT to the gingival sulcus as an in vivo periodontitis model induces an increase in the number of osteoclasts. However, the underlying mechanisms of this process remain unclear. Here, we report that Toll-like receptor 4 (TLR4) recognizes GGT to activate inflammation-associated osteoclastogenesis. Unlike lipopolysaccharide, GGT is sensitive to proteinase K treatment and insensitive to polymyxin B treatment. TLR4 deficiency abrogates GGT-induced osteoclastogenesis and activation of NF-κB and MAPK signaling in precursor cells. Additionally, GGT does not induce osteoclastogenesis in cells lacking the signaling adaptor MyD88. The administration of GGT to the gingival sulcus induces increased osteoclastogenesis in wild-type mice, but does not induce it in TLR4-deficient mice. Our findings elucidate a novel mechanism of inflammation-associated osteoclastogenesis, which involves TLR4 recognition of GGT and subsequent activation of MyD88-dependent signaling.
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Affiliation(s)
- Sawako Moriwaki
- Biobank, Medical Genome Center, National Center for Geriatrics and Gerontology, Obu 474-8511, Japan
| | - Takeshi Into
- Department of Oral Microbiology, Division of Oral Infections and Health Sciences, Asahi University School of Dentistry, Mizuho 501-0296, Japan
| | - Keiko Suzuki
- Department of Pharmacology, School of Dentistry, Showa University, Tokyo 142-8555, Japan
| | - Mutsumi Miyauchi
- Department of Oral and Maxillofacial Pathology, Institute of Biomedical &Health Sciences, Hiroshima University, Hiroshima 734-8522, Japan
| | - Takashi Takata
- Department of Oral and Maxillofacial Pathology, Institute of Biomedical &Health Sciences, Hiroshima University, Hiroshima 734-8522, Japan
| | - Keigo Shibayama
- Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo 208-0011, Japan
| | - Shumpei Niida
- Biobank, Medical Genome Center, National Center for Geriatrics and Gerontology, Obu 474-8511, Japan
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Abstract
The transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2) is a major regulator of oxidative stress defence in the human body. As Nrf2 regulates the expression of a large battery of cytoprotective genes, it plays a crucial role in the prevention of degenerative disease in multiple organs. Thus it has been the focus of research as a pharmacological target that could be used for prevention and treatment of chronic diseases such as multiple sclerosis, chronic kidney disease or cardiovascular diseases. The present review summarizes promising findings from basic research and shows which Nrf2-targeting therapies are currently being investigated in clinical trials and which agents have already entered clinical practice.
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Association of Nrf2 with airway pathogenesis: lessons learned from genetic mouse models. Arch Toxicol 2015; 89:1931-57. [PMID: 26194645 DOI: 10.1007/s00204-015-1557-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 06/17/2015] [Indexed: 01/11/2023]
Abstract
Nrf2 is a key transcription factor for antioxidant response element (ARE)-bearing genes involved in diverse host defense functions including redox balance, cell cycle, immunity, mitochondrial biogenesis, energy metabolism, and carcinogenesis. Nrf2 in the airways is particularly essential as the respiratory system continuously interfaces with environmental stress. Since Nrf2 was determined to be a susceptibility gene for a model of acute lung injury, its protective capacity in the airways has been demonstrated in experimental models of human disorders using Nrf2 mutant mice which were susceptible to supplemental respiratory therapy (e.g., hyperoxia, mechanical ventilation), cigarette smoke, allergens, virus, environmental pollutants, and fibrotic agents compared to wild-type littermates. Recent studies also determined that Nrf2 is indispensable in developmental lung injury. While association studies with genetic NRF2 polymorphisms supported a protective role for murine Nrf2 in oxidative airway diseases, somatic NRF2 mutations enhanced NRF2-ARE responses, and were favorable for lung carcinogenesis and chemoresistance. Bioinformatic tools have elucidated direct Nrf2 targets as well as Nrf2-interacting networks. Moreover, potent Nrf2-ARE agonists protected oxidant-induced lung phenotypes in model systems, suggesting a therapeutic or preventive intervention. Further investigations on Nrf2 should yield greater understanding of its contribution to normal and pathophysiological function in the airways.
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Abstract
The expression of gamma-glutamyl transpeptidase (GGT) is essential to maintaining cysteine levels in the body. GGT is a cell surface enzyme that hydrolyzes the gamma-glutamyl bond of extracellular reduced and oxidized glutathione, initiating their cleavage into glutamate, cysteine (cystine), and glycine. GGT is normally expressed on the apical surface of ducts and glands, salvaging the amino acids from glutathione in the ductal fluids. GGT in tumors is expressed over the entire cell membrane and provides tumors with access to additional cysteine and cystine from reduced and oxidized glutathione in the blood and interstitial fluid. Cysteine is rate-limiting for glutathione synthesis in cells under oxidative stress. The induction of GGT is observed in tumors with elevated levels of intracellular glutathione. Studies in models of hepatocarcinogenesis show that GGT expression in foci of preneoplastic hepatocytes provides a selective advantage to the cells during tumor promotion with agents that deplete intracellular glutathione. Similarly, expression of GGT in tumors enables cells to maintain elevated levels of intracellular glutathione and to rapidly replenish glutathione during treatment with prooxidant anticancer therapy. In the clinic, the expression of GGT in tumors is correlated with drug resistance. The inhibitors of GGT block GGT-positive tumors from accessing the cysteine in extracellular glutathione. They also inhibit GGT activity in the kidney, which results in the excretion of GSH in the urine and a rapid decrease in blood cysteine levels, leading to depletion of intracellular GSH in both GGT-positive and GGT-negative tumors. GGT inhibitors are being developed for clinical use to sensitize tumors to chemotherapy.
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Affiliation(s)
- Marie H Hanigan
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
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Myocardial glutathione metabolic status in fat-fed rabbits. Mol Cell Biochem 2014; 390:243-51. [DOI: 10.1007/s11010-014-1975-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
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Yamada K, Tsuji T, Kunieda T. Phenotypic characterization of Ggt1(dwg/dwg) mice,a mouse model for hereditary γ-glutamyltransferase deficiency. Exp Anim 2013; 62:151-7. [PMID: 23615310 DOI: 10.1538/expanim.62.151] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Ggt1(dwg/dwg) mice are spontaneous mutant mice with a nucleotide deletion in the Ggt1 gene. They are characterized by dwarfism, cataract, and coat color abnormality. These abnormalities in the external appearance of Ggt1(dwg/dwg) mice closely resemble those of previously reported GGT1-deficient mice, Ggt1(tm1Zuk/tm1Zuk) (Ggt1(-/-)) and Ggt1(enu1/enu1), generated by gene targeting or ENU mutagenesis. However, whether the pathological features of Ggt1(dwg/dwg) mice are also similar to those of the Ggt1(-/-) and Ggt1(enu1/enu1) mice remains unclear. To clarify the pathogenesis of Ggt1(dwg/dwg) mice, we physiologically and histologically investigated the abnormalities of Ggt1(dwg/dwg) mice in this study. First, we analyzed the activity of GGT1 and GSH levels in Ggt1(dwg/dwg) mice. GGT1 activity in the Ggt1(dwg/dwg) mice was reduced to approximately 4.0% of that in the wild-type mice. Plasma and kidney GSH levels were markedly increased, while eye and liver GSH levels were markedly decreased, in the Ggt1(dwg/dwg) mice. Notably, no significant difference in survival rate was observed between the Ggt1(dwg/dwg) and wild-type mice, whereas high mortality was reported in the Ggt1(-/-) and Ggt1(enu1/enu1) mice. Growth retardation, degeneration of lens fibers, and an increased number of osteoclasts in the Ggt1(dwg/dwg) mice were reversed by administration of N-acetyl-L-cysteine, a precursor of GSH synthesis. Thus, we conclude that the abnormalities of Ggt1(dwg/dwg) mice are caused by alteration of the GSH levels due to the depression of GGT1 activity and that Ggt1(dwg/dwg) mice will be a useful model for GGT deficiency with peculiar features.
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Affiliation(s)
- Kaoru Yamada
- Graduate School of Natural Science and Technology, Okayama University, 1-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
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Locy ML, Rogers LK, Prigge JR, Schmidt EE, Arnér ESJ, Tipple TE. Thioredoxin reductase inhibition elicits Nrf2-mediated responses in Clara cells: implications for oxidant-induced lung injury. Antioxid Redox Signal 2012; 17:1407-16. [PMID: 22607006 PMCID: PMC3437047 DOI: 10.1089/ars.2011.4377] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
AIMS Pulmonary oxygen toxicity contributes to lung injury in newborn and adult humans. We previously reported that thioredoxin reductase (TrxR1) inhibition with aurothioglucose (ATG) attenuates hyperoxic lung injury in adult mice. The present studies tested the hypothesis that TrxR1 inhibition protects against the effects of hyperoxia via nuclear factor E2-related factor 2 (Nrf2)-dependent mechanisms. RESULTS Both pharmacologic and siRNA-mediated TrxR1 inhibition induced robust Nrf2 responses in murine-transformed Clara cells (mtCC). While TrxR1 inhibition did not alter the susceptibility of cells to the effects of hyperoxia, glutathione (GSH) depletion after TrxR1 inhibition markedly enhanced the hyperoxic susceptibility of cultured mtCCs. Finally, in vivo data revealed dose-dependent increases in the expression of the Nrf2 target gene NADPH:quinone oxidoreductase 1 (NQO1) in the lungs of ATG-treated adult mice. INNOVATION TrxR1 inhibition activates Nrf2-dependent antioxidant responses in mtCCs in vitro and in adult murine lungs in vivo, providing a plausible mechanism for the protective effects of TrxR1 inhibition in vivo. CONCLUSION GSH-dependent enzyme systems in mtCCs may be of greater importance for protection against hyperoxic exposure than are TrxR-dependent systems. The induction of Nrf2 activation via TrxR1 inhibition represents a novel therapeutic strategy that attenuates oxidant-mediated lung injury. Similar expression levels of TrxR1 in newborn and adult mouse or human lungs broaden the potential clinical applicability of the present findings to both neonatal and adult oxidant lung injury.
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Affiliation(s)
- Morgan L Locy
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
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15
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The protective effect of losartan in the nephropathy of the diabetic rat includes the control of monoamine oxidase type A activity. Pharmacol Res 2012; 65:465-71. [DOI: 10.1016/j.phrs.2011.11.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 11/14/2011] [Accepted: 11/14/2011] [Indexed: 11/24/2022]
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16
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17
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Pica A, Russo Krauss I, Castellano I, Rossi M, La Cara F, Graziano G, Sica F, Merlino A. Exploring the unfolding mechanism of γ-glutamyltranspeptidases: the case of the thermophilic enzyme from Geobacillus thermodenitrificans. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:571-7. [PMID: 22322192 DOI: 10.1016/j.bbapap.2012.01.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/19/2012] [Accepted: 01/23/2012] [Indexed: 10/14/2022]
Abstract
γ-glutamyltranspeptidases (γ-GTs) are ubiquitous enzymes that catalyze the hydrolysis of γ-glutamyl bonds in glutathione and glutamine and the transfer of the released γ-glutamyl group to amino acids or short peptides. These enzymes are generally synthesized as precursor proteins, which undergo an intra-molecular autocatalytic cleavage yielding a large and a small subunit. In this study, circular dichroism and intrinsic fluorescence measurements have been used to investigate the structural features and the temperature- and guanidinium hydrochloride (GdnHCl)-induced unfolding of the mature form of the γ-GT from Geobacillus thermodenitrificans (GthGT) and that of its T353A mutant, which represents a mimic of the precursor protein. Data indicate that a) the mutant and the mature GthGT have a different secondary structure content and a slightly different exposure of hydrophobic regions, b) the thermal unfolding processes of both GthGT forms occur through a three-state model, characterized by a stable intermediate species, whereas chemical denaturations proceed through a single transition, c) both GthGT forms exhibit remarkable stability against temperature, but they do not display a strong resistance to the denaturing action of GdnHCl. These findings suggest that electrostatic interactions significantly contribute to the protein stability and that both the precursor and the mature form of GthGT assume compact and stable conformations to resist to the extreme temperatures where G. thermodenidrificans lives. Owing to its thermostability and unique catalytic properties, GthGT is an excellent candidate to be used as a glutaminase in food industry.
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Affiliation(s)
- Andrea Pica
- Department of Chemical Sciences, University of Naples, Naples, Italy
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Joyce-Brady M, Hiratake J. Inhibiting Glutathione Metabolism in Lung Lining Fluid as a Strategy to Augment Antioxidant Defense. ACTA ACUST UNITED AC 2011; 7:71-78. [PMID: 22485086 PMCID: PMC3319921 DOI: 10.2174/157340811796575308] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 03/25/2011] [Accepted: 04/08/2011] [Indexed: 12/22/2022]
Abstract
Glutathione is abundant in the lining fluid that bathes the gas exchange surface of the lung. On the one hand glutathione in this extracellular pool functions in antioxidant defense to protect cells and proteins in the alveolar space from oxidant injury; on the other hand, it functions as a source of cysteine to maintain cellular glutathione and protein synthesis. These seemingly opposing functions are regulated through metabolism by gamma-glutamyl transferase (GGT, EC 2.3.2.2). Even under normal physiologic conditions, lung lining fluid (LLF) contains a concentrated pool of GGT activity exceeding that of whole lung by about 7-fold and indicating increased turnover of glutathione at the epithelial surface of the lung. With oxidant stress LLF GGT activity is amplified even further as glutathione turnover is accelerated to meet the increased demands of cells for cysteine. Mouse models of GGT deficiency confirmed this biological role of LLF GGT activity and revealed the robust expansiveness and antioxidant capacity of the LLF glutathione pool in the absence of metabolism. Acivicin, an irreversible inhibitor of GGT, can be utilized to augment LLF fluid glutathione content in normal mice and novel GGT inhibitors have now been defined that provide advantages over acivicin. Inhibiting LLF GGT activity is a novel strategy to selectively augment the extracellular LLF glutathione pool. The enhanced antioxidant capacity can maintain lung epithelial cell integrity and barrier function under oxidant stress.
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Affiliation(s)
- Martin Joyce-Brady
- The Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA
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19
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Fujii J, Ito JI, Zhang X, Kurahashi T. Unveiling the roles of the glutathione redox system in vivo by analyzing genetically modified mice. J Clin Biochem Nutr 2011; 49:70-8. [PMID: 21980221 PMCID: PMC3171681 DOI: 10.3164/jcbn.10-138sr] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 12/31/2010] [Indexed: 12/19/2022] Open
Abstract
Redox status affects various cellular activities, such as proliferation, differentiation, and death. Recent studies suggest pivotal roles of reactive oxygen species not only in pathogenesis under oxidative insult but also in intracellular signal transduction. Glutathione is present in several millimolar concentrations in the cytoplasm and has multiple roles in the regulation of cellular homeostasis. Two enzymes, γ-glutamylcysteine synthetase and glutathione synthetase, constitute the de novo synthesis machinery, while glutathione reductase is involved in the recycling of oxidized glutathione. Multidrug resistant proteins and some other transporters are responsible for exporting oxidized glutathione, glutathione conjugates, and S-nitrosoglutathione. In addition to antioxidation, glutathione is more positively involved in cellular activity via its sulfhydryl moiety of a molecule. Animals in which genes responsible for glutathione metabolism are genetically modified can be used as beneficial and reliable models to elucidate roles of glutathione in vivo. This review article overviews recent progress in works related to genetically modified rodents and advances in the elucidation of glutathione-mediated reactions.
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Affiliation(s)
- Junichi Fujii
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
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20
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Gamma-glutamyl compounds: substrate specificity of gamma-glutamyl transpeptidase enzymes. Anal Biochem 2011; 414:208-14. [PMID: 21447318 DOI: 10.1016/j.ab.2011.03.026] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 03/19/2011] [Accepted: 03/23/2011] [Indexed: 11/23/2022]
Abstract
Gamma-glutamyl compounds include antioxidants, inflammatory molecules, drug metabolites, and neuroactive compounds. Two cell surface enzymes that metabolize gamma-glutamyl compounds have been identified: gamma-glutamyl transpeptidase (GGT1) and gamma-glutamyl leukotrienase (GGT5). There is controversy in the literature regarding the substrate specificity of these enzymes. To address this issue, we have developed a method for comprehensive kinetic analysis of compounds as substrates for GGT enzymes. Our assay is sensitive, quantitative, and conducted at physiological pH. We evaluated a series of gamma-glutamyl compounds as substrates for human GGT1 and human GGT5. The K(m) value for reduced glutathione was 11μM for both GGT1 and GGT5. However, the K(m) values for oxidized glutathione were 9μM for GGT1 and 43μM for GGT5. Our data show that the K(m) values for leukotriene C(4) are equivalent for GGT1 and GGT5 at 10.8 and 10.2μM, respectively. This assay was also used to evaluate serine-borate, a well-known inhibitor of GGT1, which was 8-fold more potent in inhibiting GGT1 than in inhibiting GGT5. These data provide essential information regarding the target enzymes for developing treatments for inflammatory diseases such as asthma and cardiovascular disease in humans. This assay is invaluable for studies of oxidative stress, drug metabolism, and other pathways that involve gamma-glutamyl compounds.
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21
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Janssen-Heininger YMW, Aesif SW, van der Velden J, Guala AS, Reiss JN, Roberson EC, Budd RC, Reynaert NL, Anathy V. Regulation of apoptosis through cysteine oxidation: implications for fibrotic lung disease. Ann N Y Acad Sci 2010; 1203:23-8. [PMID: 20716279 DOI: 10.1111/j.1749-6632.2010.05553.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tissue fibrosis is believed to be a manifestation of dysregulated repair following injury, in association with impaired reepithelialization, and aberrant myofibroblast activation and proliferation. Numerous pathways have been linked to the pathogenesis of fibrotic lung disease, including the death receptor Fas, which contributes to apoptosis of lung epithelial cells. A redox imbalance also has been implicated in disease pathogenesis, although mechanistic details whereby oxidative changes intersect with profibrotic signaling pathways remain elusive. Oxidation of cysteines in proteins, such as S-glutathionylation (PSSG), is known to act as a regulatory event that affects protein function. This manuscript will discuss evidence that S-glutathionylation regulates death receptor induced apoptosis, and the potential implications for cysteine oxidations in the pathogenesis of in fibrotic lung disease.
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22
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Vassallo JD, Kaetzel RS, Born SL, Lewis CL, Lehman-McKeeman LD, Reed DJ. Gamma-glutamyl transpeptidase null mice fail to develop tolerance to coumarin-induced Clara cell toxicity. Food Chem Toxicol 2010; 48:1612-8. [PMID: 20347914 DOI: 10.1016/j.fct.2010.03.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 03/15/2010] [Accepted: 03/22/2010] [Indexed: 01/22/2023]
Abstract
Coumarin was used as a model Clara cell toxicant to test the hypothesis that tolerance to injury requires increased gamma-glutamyl transpeptidase (GGT) activity. Wildtype (GGT(+/+)) and GGT-deficient (GGT(-/-)) mice on a C57BL/6/129SvEv hybrid background were dosed orally with corn oil (vehicle) or coumarin (200 mg/kg). In vehicle-treated mice, Clara cell secretory protein (CC10) expression was distributed throughout the bronchiolar epithelium. After one dose of coumarin, CC10 expression was dramatically reduced and the bronchiolar epithelium was devoid of Clara cells in GGT(+/+) and GGT(-/-) mice. In wildtype mice, 9 doses of coumarin produced tolerance, characterized as a renewed bronchiolar epithelium with Clara cells expressing CC10 along with a 40% increase in total glutathione (GSH) and a 7-fold increase in GGT activity in the lung. In contrast, tolerance was not observed in GGT(-/-) mice. To assess whether changes in whole lung levels of GSH and GGT activity reflect Clara cell specific changes an enriched population of cells was isolated from female wildtype B6C3F1 mice made tolerant to coumarin. Compared to Clara cells from control mice, GSH and GGT activity increased 3- and 13-fold, respectively. Collectively, these data suggest Clara cell tolerance to coumarin toxicity requires increased GGT activity favoring enhanced GSH synthesis.
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Affiliation(s)
- Jeffrey D Vassallo
- Miami Valley Innovation Center, The Procter and Gamble Company, Cincinnati, OH 45252, USA.
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23
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Klings ES, Lowry MH, Li G, Jean JC, Fernandez BO, Garcia-Saura MF, Feelisch M, Joyce-Brady M. Hyperoxia-induced lung injury in gamma-glutamyl transferase deficiency is associated with alterations in nitrosative and nitrative stress. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:2309-18. [PMID: 19850887 DOI: 10.2353/ajpath.2009.081017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
gamma-Glutamyl transferase (GGT) regulates glutathione metabolism and cysteine supply. GGT inactivation in GGT(enu1) mice limits cysteine availability causing cellular glutathione deficiency. In lung, the resultant oxidant burden is associated with increased nitric oxide (NO) production, yet GGT(enu1) mice still exhibit higher mortality in hyperoxia. We hypothesized that NO metabolism is altered under severe oxidant stress and contributes to lung cellular injury and death. We compared lung injury, NO synthase (NOS) expression, nitrate/nitrite production, nitroso product formation, peroxynitrite accumulation, and cell death in wild-type and GGT(enu1) mice in normoxia and hyperoxia. The role of NOS activity in cell death was determined by NOS inhibition. Exposure of wild-type mice to hyperoxia caused increased lung injury, altered NO metabolism, and induction of cell death compared with normoxia, which was attenuated by NOS inhibition. Each of these lung injury indices were magnified in hyperoxia-exposed GGT(enu1) mice except nitrosation, which showed a diminished decrease compared with wild-type mice. NOS inhibition attenuated cell death only slightly, likely due to further exacerbation of oxidant stress. Taken together, these data suggest that apoptosis in hyperoxia is partially NO-dependent and reiterate the importance of cellular glutathione in lung antioxidant defense. Therefore, reduced denitrosylation of proteins, possibly resulting in impaired cellular repair, and excessive apoptotic cell death likely contribute to increased lung injury and mortality of GGT(enu1) mice in hyperoxia.
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Affiliation(s)
- Elizabeth S Klings
- Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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24
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Zhang H, Forman HJ. Redox regulation of gamma-glutamyl transpeptidase. Am J Respir Cell Mol Biol 2009; 41:509-15. [PMID: 19684307 DOI: 10.1165/rcmb.2009-0169tr] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
gamma-Glutamyl transpeptidase (GGT) catalyzes the transfer of the glutamyl moiety from glutathione, and glutathione S-conjugates to acceptors to form another amide or to water to produce free glutamate. Functionally, GGT plays important roles in glutathione homeostasis and mercapturic acid metabolism. The expression of GGT is increased as an adaptive response upon the exposure of oxidative stress. The underlying mechanism of this, however, is nebulous, as GGT gene structure is complex and its transcription is usually controlled by multiple promoters that generate several subtypes of GGT mRNAs. Studies reveal that signaling pathways such as Ras, ERK, p38MAPK, and PI3K are involved in the induction of GGT gene expression in response to oxidative stress. Thus, not surprisingly, induction of GGT mRNA subtypes and the involvement of multiple signaling pathways vary depending on cell type and stimuli.
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Affiliation(s)
- Hongqiao Zhang
- School of Natural Sciences, University of California, Merced, Merced, CA 95340, USA
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25
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Nrf2 protects against airway disorders. Toxicol Appl Pharmacol 2009; 244:43-56. [PMID: 19646463 DOI: 10.1016/j.taap.2009.07.024] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 07/17/2009] [Accepted: 07/22/2009] [Indexed: 11/23/2022]
Abstract
Nuclear factor-erythroid 2 related factor 2 (Nrf2) is a ubiquitous master transcription factor that regulates antioxidant response elements (AREs)-mediated expression of antioxidant enzyme and cytoprotective proteins. In the unstressed condition, Kelch-like ECH-associated protein 1 (Keap1) suppresses cellular Nrf2 in cytoplasm and drives its proteasomal degradation. Nrf2 can be activated by diverse stimuli including oxidants, pro-oxidants, antioxidants, and chemopreventive agents. Nrf2 induces cellular rescue pathways against oxidative injury, abnormal inflammatory and immune responses, apoptosis, and carcinogenesis. Application of Nrf2 germ-line mutant mice has identified an extensive range of protective roles for Nrf2 in experimental models of human disorders in the liver, gastrointestinal tract, airway, kidney, brain, circulation, and immune or nerve system. In the lung, lack of Nrf2 exacerbated toxicity caused by multiple oxidative insults including supplemental respiratory therapy (e.g., hyperoxia, mechanical ventilation), cigarette smoke, allergen, virus, bacterial endotoxin and other inflammatory agents (e.g., carrageenin), environmental pollution (e.g., particles), and a fibrotic agent bleomycin. Microarray analyses and bioinformatic studies elucidated functional AREs and Nrf2-directed genes that are critical components of signaling mechanisms in pulmonary protection by Nrf2. Association of loss of function with promoter polymorphisms in NRF2 or somatic and epigenetic mutations in KEAP1 and NRF2 has been found in cohorts of patients with acute lung injury/acute respiratory distress syndrome or lung cancer, which further supports the role for NRF2 in these lung diseases. In the current review, we address the role of Nrf2 in airways based on emerging evidence from experimental oxidative disease models and human studies.
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Elshorbagy AK, Refsum H, Smith AD, Graham IM. The association of plasma cysteine and gamma-glutamyltransferase with BMI and obesity. Obesity (Silver Spring) 2009; 17:1435-40. [PMID: 19214177 DOI: 10.1038/oby.2008.671] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We recently reported a strong positive association of plasma total cysteine (tCys) with fat mass in over 5,000 subjects. As gamma-glutamyltransferase (GGT) enzyme increases cysteine availability by catalyzing glutathione breakdown and is positively associated with BMI and adiposity, we hypothesized that GGT might explain the association of tCys with adiposity. To study whether the associations of tCys and serum GGT with BMI and obesity were interrelated we conducted a cross-sectional study using data from 1,550 subjects recruited from nine European countries in the COMAC project. Multiple linear and logistic regression models and concentration-response curves were used. In age and sex-adjusted analyses, tCys showed strong positive associations with BMI (partial r = 0.19, P < 0.001), and obesity (odds ratio (OR) for 4th vs. 1st tCys quartile: 2.8; 95% confidence interval: 1.6-5.0, P < 0.001), both of which remained robust after adjustment for GGT and other metabolic and lifestyle confounders. Serum GGT was also a positive predictor of BMI (partial r = 0.17, P < 0.001) and obesity (OR for 4th vs. 1st GGT quartile: 4.8; 95% confidence interval: 2.5-9.2, P < 0.001), independent of tCys. However, the associations of GGT with BMI and obesity were weakened by adjustment for obesity-related factors such as serum lipids and blood pressure. These results indicate that tCys is a strong positive predictor of BMI and obesity, independent of GGT and other obesity-related factors. We also suggest that the association of serum GGT with BMI and obesity is unrelated to the role of GGT in cysteine turnover. The potential link between cysteine and fat metabolism should be further evaluated.
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Affiliation(s)
- Amany K Elshorbagy
- Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, UK.
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Ratner V, Slinko S, Utkina-Sosunova I, Starkov A, Polin RA, Ten VS. Hypoxic stress exacerbates hyperoxia-induced lung injury in a neonatal mouse model of bronchopulmonary dysplasia. Neonatology 2009; 95:299-305. [PMID: 19052476 PMCID: PMC3659784 DOI: 10.1159/000178798] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Accepted: 05/14/2008] [Indexed: 11/19/2022]
Abstract
BACKGROUND Premature infants with lung injury often experience intermittent episodes of hypoxemia. OBJECTIVE This study investigates whether intermittent hypoxemia exacerbates oxidative stress and lung injury in neonatal mice in a hyperoxia-induced model of bronchopulmonary dysplasia (BPD). METHODS For the BPD model, 3-day-old C57Bl/6J mice were exposed to hyperoxia (65% O(2)) for 4 weeks (O(2) group) or to hyperoxia and intermittent (10 min daily) hypoxia (O(2) + H group). Upon completion of O(2) or O(2) + H exposure, the degree of pulmonary alveolarization and granulocytic infiltration were examined. The severity of oxidative injury in lungs was defined by tissue glutathione and protein carbonyl content. Data were compared to those in naïve mice and mice subjected only to intermittent hypoxia. RESULTS Hyperoxia-exposed mice exhibited a dramatic (p < 0.0001) decrease of alveolarization, significantly increased granulocytic infiltration (p < 0.0001) and increased protein carbonyl content (p = 0.04) compared to naïve mice. However, O(2) + H mice demonstrated significantly (p = 0.03) fewer alveoli compared to their O(2) counterparts. This was associated with a significantly (p = 0.02) decreased pulmonary total/oxidized glutathione ratio and a significant (p = 0.03) elevation of protein carbonyl content. CONCLUSIONS Thus, intermittent hypoxic stress during hyperoxic induction of BPD in mice potentiates oxidative stress in lung tissue and exacerbates alveolar developmental arrest.
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Affiliation(s)
- Veniamin Ratner
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
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28
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Bentley AR, Emrani P, Cassano PA. Genetic variation and gene expression in antioxidant related enzymes and risk of COPD: a systematic review. Thorax 2008; 63:956-61. [PMID: 18566111 DOI: 10.1136/thx.2007.086199] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Observational epidemiological studies of dietary antioxidant intake, serum antioxidant concentration and lung outcomes suggest that lower levels of antioxidant defences are associated with decreased lung function. Another approach to understanding the role of oxidant/antioxidant imbalance in the risk of chronic obstructive pulmonary disease (COPD) is to investigate the role of genetic variation in antioxidant enzymes, and indeed family based studies suggest a heritable component to lung disease. Many studies of the genes encoding antioxidant enzymes have considered COPD or COPD related outcomes, and a systematic review is needed to summarise the evidence to date, and to provide insights for further research. METHODS Genetic association studies of antioxidant enzymes and COPD/COPD related traits, and comparative gene expression studies with disease or smoking as the exposure were systematically identified and reviewed. Antioxidant enzymes considered included enzymes involved in glutathione metabolism, in the thioredoxin system, superoxide dismutases (SOD) and catalase. RESULTS A total of 29 genetic association and 15 comparative gene expression studies met the inclusion criteria. The strongest and most consistent effects were in the genes GCL, GSTM1, GSTP1 and SOD3. This review also highlights the lack of studies for genes of interest, particularly GSR, GGT and those related to TXN. There were limited opportunities to evaluate the contribution of a gene to disease risk through synthesis of results from different study designs, as the majority of studies considered either association of sequence variants with disease or effect of disease on gene expression. CONCLUSION Network driven approaches that consider potential interaction between and among genes, smoke exposure and antioxidant intake are needed to fully characterise the role of oxidant/antioxidant balance in pathogenesis.
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Affiliation(s)
- A R Bentley
- Division of Nutritional Sciences, 209 Savage Hall, Cornell University, Ithaca, NY 14853, USA
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29
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The human gamma-glutamyltransferase gene family. Hum Genet 2008; 123:321-32. [PMID: 18357469 DOI: 10.1007/s00439-008-0487-7] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Accepted: 03/06/2008] [Indexed: 10/22/2022]
Abstract
Assays for gamma-glutamyl transferase (GGT1, EC 2.3.2.2) activity in blood are widely used in a clinical setting to measure tissue damage. The well-characterized GGT1 is an extracellular enzyme that is anchored to the plasma membrane of cells. There, it hydrolyzes and transfers gamma-glutamyl moieties from glutathione and other gamma-glutamyl compounds to acceptors. As such, it has a critical function in the metabolism of glutathione and in the conversion of the leukotriene LTC4 to LTD4. GGT deficiency in man is rare and for the few patients reported to date, mutations in GGT1 have not been described. These patients do secrete glutathione in urine and fail to metabolize LTC4. Earlier pre-genome investigations had indicated that besides GGT1, the human genome contains additional related genes or sequences. These sequences were given multiple different names, leading to inconsistencies and confusion. Here we systematically evaluated all human sequences related to GGT1 using genomic and cDNA database searches and identified thirteen genes belonging to the extended GGT family, of which at least six appear to be active. In collaboration with the HUGO Gene Nomenclature Committee (HGNC) we have designated possible active genes with nucleotide or amino acid sequence similarity to GGT1, as GGT5 (formerly GGL, GGTLA1/GGT-rel), GGT6 (formerly rat ggt6 homologue) and GGT7 (formerly GGTL3, GGT4). Two loci have the potential to encode only the light chain portion of GGT and have now been designated GGTLC1 (formerly GGTL6, GGTLA4) and GGTLC2. Of the five full-length genes, three lack of significant nucleotide sequence homology but have significant (GGT5, GGT7) or very limited (GGT6) amino acid similarity to GGT1 and belong to separate families. GGT6 and GGT7 have not yet been described, raising the possibility that leukotriene synthesis, glutathione metabolism or gamma-glutamyl transfer is regulated by their, as of yet uncharacterized, enzymatic activities. In view of the widespread clinical use of assays that measure gamma-glutamyl transfer activity, this would appear to be of significant interest.
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Tipple TE, Welty SE, Rogers LK, Hansen TN, Choi YE, Kehrer JP, Smith CV. Thioredoxin-related mechanisms in hyperoxic lung injury in mice. Am J Respir Cell Mol Biol 2007; 37:405-13. [PMID: 17575077 PMCID: PMC2176120 DOI: 10.1165/rcmb.2006-0376oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Accepted: 04/26/2007] [Indexed: 11/24/2022] Open
Abstract
Reduction of glutathione disulfide (GSSG) to glutathione (GSH) by glutathione reductase (GR) enhances the efficiency of GSH-dependent antioxidant activities. However, GR-deficient (a1Neu) mice are less susceptible to acute lung injury from continuous exposure to > 95% O(2) (96 h: 6.9 +/- 0.1 g right lung/kg body versus room air 3.6 +/- 0.3) than are C3H/HeN control mice (10.6 +/- 1.3 versus 4.2 +/- 0.3, P < 0.001). a1Neu mice have greater hepatic thioredoxin (Trx)1 and Trx2 levels than do C3H/HeN mice, suggesting compensation for the absence of GR. a1Neu mice exposed to hyperoxia for 96 hours showed lower levels of inflammatory infiltrates in lungs than did similarly exposed C3H/HeN mice. Pretreatment with aurothioglucose (ATG), a thioredoxin reductase (TrxR) inhibitor, exacerbated the effects of hyperoxia on lung injury in a1Neu mice (11.6 +/- 0.8, P < 0.001), but attenuated hyperoxic lung edema and inflammation in C3H/HeN mice (6.3 +/- 0.4, P < 0.001). No consistent alterations were observed in lung GSH contents or liver GSH or GSSG levels after ATG pretreatment. The data suggest that modulation of Trx/TrxR systems might provide therapeutically useful alterations of cellular resistance to oxidant stresses. The protective effects of ATG against hyperoxic lung injury could prove to be particularly useful therapeutically.
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Affiliation(s)
- Trent E Tipple
- Columbus Children's Research Institute, Columbus Children's Hospital, Department of Pediatrics, The Ohio State University, Columbus, OH 43205, USA.
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Reynaert NL, Wouters EFM, Janssen-Heininger YMW. Modulation of glutaredoxin-1 expression in a mouse model of allergic airway disease. Am J Respir Cell Mol Biol 2006; 36:147-51. [PMID: 16980552 PMCID: PMC1899315 DOI: 10.1165/rcmb.2006-0259rc] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Glutaredoxins (GRX) are antioxidant enzymes that preferentially catalyze the reduction of protein-glutathione mixed disulfides. The formation of mixed disulfides with GSH is known as S-glutathionylation, a post-translational modification that is emerging as an important mode of redox signaling. Since asthma is a disease that is associated with increased oxidative stress and altered antioxidant defenses, we investigated the expression of GRX in a murine model of allergic airway disease. Sensitization and challenge of C57BL/6 mice with ovalbumin resulted in increased expression of GRX1 mRNA, as well as increased amounts of GRX1 protein and total GRX activity in the lung. Because GRX1 expression is prominent in bronchial epithelium, we isolated primary epithelial cells from mouse trachea to investigate the presence of GRX. Primary tracheal epithelial cells were found to express both GRX1 and 2 mRNA and detectable GRX activity. Treatment with IFN-gamma increased the expression of GRX1 and overall GRX activity, resulting in attenuation of protein S-glutathionylation. In contrast, TGF-beta1 caused decreased GRX1 expression and overall GRX activity, leading to markedly enhanced protein S-glutathionylation. GRX1 joins the cadre of antioxidant defenses known to be modulated during allergic airway inflammation.
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Affiliation(s)
- Niki L Reynaert
- Department of Respiratory Medicine, Maastricht University, The Netherlands
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Zhang H, Liu H, Dickinson DA, Liu RM, Postlethwait EM, Laperche Y, Forman HJ. gamma-Glutamyl transpeptidase is induced by 4-hydroxynonenal via EpRE/Nrf2 signaling in rat epithelial type II cells. Free Radic Biol Med 2006; 40:1281-92. [PMID: 16631518 PMCID: PMC2702664 DOI: 10.1016/j.freeradbiomed.2005.11.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2005] [Revised: 10/27/2005] [Accepted: 11/04/2005] [Indexed: 12/31/2022]
Abstract
gamma-Glutamyl transpeptidase (GGT) plays key roles in glutathione homeostasis and metabolism of glutathione S-conjugates. Rat GGT is transcribed via five tandemly arranged promoters into seven transcripts. The transcription of mRNA V is controlled by promoter 5. Previously we found that GGT mRNA V-2 was responsible for the induction of GGT in rat alveolar epithelial cells by 4-hydroxynonenal (HNE). In the current study, the underlying mechanism was investigated. Reporter deletion and mutation analysis demonstrated that an electrophile-response element (EpRE) in the proximal region of GGT promoter 5 (GP5) was responsible for the basal- and HNE-induced promoter activity. Gel-shift assays showed an increased binding activity of GP5 EpRE after HNE exposure. The nuclear content of NF-E2-related factor 2 (Nrf2) was significantly increased by HNE. The recruitment of Nrf2 to GP5 EpRE after HNE treatment was demonstrated by supershift and chromatin immunoprecipitation assays. The tissue expression pattern of GGT mRNA V was previously unknown. Using polymerase chain reaction, we found that GGT mRNA V-2 was expressed in many tissues in rat. Taken together, GGT mRNA V-2 is widely expressed in rat tissues and its basal and HNE-induced expression is mediated through EpRE/Nrf2 signaling.
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Affiliation(s)
- Hongqiao Zhang
- Department of Environmental Health Science, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Honglei Liu
- School of Natural Science, University of California at Merced, Atwater, CA 95301,USA
| | - Dale A. Dickinson
- Department of Environmental Health Science, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Rui-Ming Liu
- Department of Environmental Health Science, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Edward M. Postlethwait
- Department of Environmental Health Science, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yannick Laperche
- Institut National de la Sante et de la Researche Medicale, Hopital Henri Mondor, Creteil 94010, France
| | - Henry Jay Forman
- School of Natural Science, University of California at Merced, Atwater, CA 95301,USA
- Corresponding author. Fax: +1 208 498 7635. E-mail address: (H.J. Forman)
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Kinlough CL, Poland PA, Bruns JB, Hughey RP. Gamma-glutamyltranspeptidase: disulfide bridges, propeptide cleavage, and activation in the endoplasmic reticulum. Methods Enzymol 2006; 401:426-49. [PMID: 16399401 DOI: 10.1016/s0076-6879(05)01026-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
gamma-Glutamyltranspeptidase (gammaGT) is found primarily on the apical surface of epithelial and endothelial cells, where it degrades reduced and oxidized glutathione (gamma-GluCysGly) by hydrolysis of the unique gamma-glutamyl bond. Glutathione plays a key role in disulfide rearrangement in the endoplasmic reticulum (ER) and acts as a redox buffer. Previous work has shown that overexpression of gammaGT or an inactive splice variant gammaGTDelta7 mediates a redox stress response in the endoplasmic reticulum (ER) characterized by increased levels of BiP and induction of CHOP-10. To determine whether a CX(3)C motif might be the common feature of gammaGT and gammaGTDelta7 that mediates this response, we characterized disulfide bridges in gammaGT that might form between the six highly conserved Cys residues. Using site-directed mutagenesis of gammaGT, expression in Chinese Hamster Ovary (CHO) cells, metabolic labeling, and immunoblotting, our data predict disulfide formation between Cys49 and Cys73 and between Cys191 and Cys195 (the CX(3)C motif). Potential functions for this CX(3)C motif are discussed. In the course of defining the disulfides, we also noted that propeptide cleavage correlated with enzymatic activity. Because recent reports indicate that the homologous Escherichia coli gammaGT is a member of the N-terminal nucleophile (Ntn) hydrolase family, where the amino acid at the new N-terminus functions as the nucleophile for both autocatalytic cleavage and enzymatic activity, the rat gammaGT was similarly characterized. As predicted, mutations at the propeptide cleavage site coincidentally inhibit both heterodimer formation and gammaGT enzymatic activity. Analysis of early cleavage events using cell extraction into SDS indicates that propeptide cleavage occurs while gammaGT is still within the ER. Because activation and cleavage are coincident events, this raises the new question of whether an active glutathionase is present within the ER and what role gammaGT plays in modulating ER glutathione levels that are so critical for proper redox balance and disulfide formation in this compartment.
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Affiliation(s)
- Carol L Kinlough
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh, Pennsylvania, USA
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Abstract
Nuclear factor, erythroid 2 related factor 2 (Nrf2) belongs to the Cap'n'collar/basic region leucine zipper (CNC-bZIP) transcription factor family, and is activated by diverse oxidants, pro-oxidants, antioxidants, and chemopreventive agents. After phosphorylation and dissociation from the cytoplasmic inhibitor, Kelch-like ECH-associated protein 1 (Keap1), Nrf2 translocates to the nucleus and binds to an antioxidant response element (ARE). Through transcriptional induction of ARE-bearing genes that encode antioxidant-detoxifying proteins, Nrf2 activates cellular rescue pathways against oxidative injury, inflammation/immunity, apoptosis, and carcinogenesis. ARE-driven genes include direct antioxidants (e.g., GPx), thiol metabolism-associated detoxifying enzymes (e.g., GSTs), stress-response genes (e.g., HO-1), and others (e.g., PSMB5). Application of nrf2 germ-line mutant mice elucidated protective roles for Nrf2 in various models of human disorders in the liver, lung, kidney, brain, and circulation. In the lung, deficiency of nrf2 augmented injury caused by bleomycin and environmental oxidants including hyperoxia, diesel exhaust particles, and cigarette smoke. Microarray analyses of lungs from nrf2-deficient and -sufficient mice identified Nrf2-dependent genes that might be critical in pulmonary protection. Observations from these studies highlight the importance of the Nrf2-antioxidant pathway and may provide new therapeutic strategies for acute respiratory distress syndrome, idiopathic pulmonary fibrosis, cancer, and emphysema in which oxidative stress is implicated.
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Affiliation(s)
- Hye-Youn Cho
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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Zhang H, Liu H, Iles KE, Liu RM, Postlethwait EM, Laperche Y, Forman HJ. 4-Hydroxynonenal induces rat gamma-glutamyl transpeptidase through mitogen-activated protein kinase-mediated electrophile response element/nuclear factor erythroid 2-related factor 2 signaling. Am J Respir Cell Mol Biol 2005; 34:174-81. [PMID: 16195535 PMCID: PMC2696200 DOI: 10.1165/rcmb.2005-0280oc] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Gamma-glutamyl transpeptidase (GGT) plays critical roles in glutathione homeostasis and metabolism. Rat GGT is a single-copy gene from which seven types of GGT mRNA with a common protein encoding sequence, but different 5'-untranslated regions, may be transcribed. We previously showed that type V-2 was the predominant form of GGT mRNA in rat L2 epithelial cells, and that it could be induced by 4-hydroxynonenal (HNE) through the electrophile response element (EpRE) located in GGT promoter 5 (GP5). Here, we report transcription factors binding to GP5 EpRE and the involved signaling pathways. Immunodepletion gel shift assays demonstrated that GP5 EpRE bound JunB, c-Jun, FosB, and Fra2 from unstimulated cells, and that after exposure to HNE, EpRE binding complexes contained nuclear factor erythroid 2-related factor (Nrf) 1, Nrf2, JunB, c-Jun, FosB, c-Fos, Fra1, and Fra2. HNE-induced binding of Nrf2 and c-Jun in GP5 EpRE was confirmed by chromatin immunoprecipitation assays. Using reporter assays and specific inhibitors, we found that HNE induction of rat GGT mRNA V-2 was dependent on activation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), but not protein kinase C or phosphatidylinositol 3-kinase. Pretreatment with ERK and p38MAPK inhibitors also blocked HNE-increased EpRE binding. HNE-increased nuclear content of Nrf1, Nrf2, and c-Jun in L2 cells was partially blocked by inhibition of either ERK1/2 or p38MAPK and completely blocked by simultaneous inhibition of both MAPKs. In conclusion, HNE induces GGT mRNA V-2 through altered EpRE transcription factor binding mediated by both ERK and p38MAPK.
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Affiliation(s)
- Hongqiao Zhang
- Department of Environmental Health Science, School of Public Health, University of Alabama at Birmingham, USA
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Zhang H, Dickinson DA, Liu RM, Forman HJ. 4-Hydroxynonenal increases gamma-glutamyl transpeptidase gene expression through mitogen-activated protein kinase pathways. Free Radic Biol Med 2005; 38:463-71. [PMID: 15649648 PMCID: PMC2801023 DOI: 10.1016/j.freeradbiomed.2004.10.031] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Accepted: 10/13/2004] [Indexed: 01/13/2023]
Abstract
gamma-Glutamyl transpeptidase (GGT) plays key roles in the metabolism of glutathione. Previous studies have shown that GGT expression was increased by oxidants, but the mechanism remains unclear. In the present study, the effects of 4-hydroxy-2-nonenal (HNE), an electrophilic end product of lipid peroxidation, on GGT expression were investigated in rat lung epithelial type II (L2) cells. We demonstrated that HNE increased GGT activity and mRNA content in both time- and dose-dependent manners. Actinomycin D, an RNA transcription inhibitor, blocked HNE-stimulated increase in GGT mRNA, suggesting transcriptional regulation of GGT mRNA by HNE. Of the seven GGT mRNA transcripts known to be produced from the single rat GGT gene, we found that types I, II, and V-2 were constitutively expressed in L2 cells, but only types I and V-2 were increased by HNE. PD98059 and SB203580, relatively specific inhibitors of the ERK and the p38MAPK kinase pathway, respectively, significantly attenuated HNE induction of both GGT activity and mRNA content. In contrast, studies with JNK inhibitor I, a cell-permeable peptide, indicated that JNK was not involved in the GGT induction by HNE. We also found that GGT induction by HNE could be completely blocked by a cocktail of PD98059 and SB203580, suggesting a combined effect of ERK and p38MAPK pathways in HNE-mediated GGT induction. In conclusion, our results demonstrate that HNE increased GGT expression in rat alveolar type II cells and that the induction of GGT by HNE was mediated through activation of the ERK and p38MAPK pathways.
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Affiliation(s)
- Hongqiao Zhang
- Department of Environmental Health Science, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Dale A. Dickinson
- Department of Environmental Health Science, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Rui-Ming Liu
- Department of Environmental Health Science, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Henry Jay Forman
- School of Natural Science, University of California at Merced, Atwater, CA 95301, USA
- Corresponding author. Fax: (208) 498 7635. (H.J. Forman)
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Cho HY, Reddy SP, Debiase A, Yamamoto M, Kleeberger SR. Gene expression profiling of NRF2-mediated protection against oxidative injury. Free Radic Biol Med 2005; 38:325-43. [PMID: 15629862 DOI: 10.1016/j.freeradbiomed.2004.10.013] [Citation(s) in RCA: 195] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Accepted: 10/06/2004] [Indexed: 11/19/2022]
Abstract
Nuclear factor E2 p45-related factor 2 (NRF2) contributes to cellular protection against oxidative insults and chemical carcinogens via transcriptional activation of antioxidant/detoxifying enzymes. To understand the molecular basis of NRF2-mediated protection against oxidative lung injury, pulmonary gene expression profiles were characterized in Nrf2-disrupted (Nrf2(-/-)) and wild-type (Nrf2(+/+)) mice exposed to hyperoxia or air. Genes expressed constitutively higher in Nrf2(+/+) mice than in Nrf2(-/-) mice included antioxidant defense enzyme and immune cell receptor genes. Higher basal expression of heat shock protein and structural genes was detected in Nrf2(-/-) mice relative to Nrf2(+/+) mice. Hyperoxia enhanced expression of 175 genes (> or = twofold) and decreased expression of 100 genes (> or =50%) in wild-type mice. Hyperoxia-induced upregulation of many well-known/new antioxidant/defense genes (e.g., Txnrd1, Ex, Cp-2) and other novel genes (e.g., Pkc-alpha, Tcf-3, Ppar-gamma) was markedly greater in Nrf2(+/+) mice than in Nrf2(-/-) mice. In contrast, induced expression of genes encoding extracellular matrix and cytoskeletal proteins was higher in Nrf2(-/-) mice than in Nrf2(+/+) mice. These NRF2-dependent gene products might have key roles in protection against hyperoxic lung injury. Results from our global gene expression profiles provide putative downstream molecular mechanisms of oxygen tissue toxicity.
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Affiliation(s)
- Hye-Youn Cho
- Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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38
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Abstract
Glutathione (GSH) is the most abundant nonprotein thiol in cells and has multiple biological functions. Glutathione biosynthesis by way of the gamma-glutamyl cycle is important for maintaining GSH homeostasis and normal redox status. As the only enzyme of the cycle located on the outer surface of plasma membrane, gamma-glutamyl transpeptidase (GGT) plays key roles in GSH homeostasis by breaking down extracellular GSH and providing cysteine, the rate-limiting substrate, for intracellular de novo synthesis of GSH. GGT also initiates the metabolism of glutathione S-conjugates to mercapturic acids by transferring the gamma-glutamyl moiety to an acceptor amino acid and releasing cysteinylglycine. GGT is expressed in a tissue-, developmental phase-, and cell-specific manner that may be related to its complex gene structure. In rodents, there is a single GGT gene, and several promoters that generate different mRNA subtypes and regulate its expression. In contrast, several GGT genes have been found in humans. During oxidative stress, GGT gene expression is increased, and this is believed to constitute an adaptation to stress. Interestingly, only certain mRNA subtypes are increased, suggesting a specific mode of regulation of GGT gene expression by oxidants. Here, protocols to measure GGT activity, relative levels of total and specific GGT mRNA subtypes, and GSH concentration are described.
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Affiliation(s)
- Hongqiao Zhang
- School of Natural Sciences, University of California Merced, USA
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39
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Dalton TP, Chen Y, Schneider SN, Nebert DW, Shertzer HG. Genetically altered mice to evaluate glutathione homeostasis in health and disease. Free Radic Biol Med 2004; 37:1511-26. [PMID: 15477003 DOI: 10.1016/j.freeradbiomed.2004.06.040] [Citation(s) in RCA: 206] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Revised: 06/17/2004] [Accepted: 06/24/2004] [Indexed: 01/15/2023]
Abstract
The tripeptide glutathione (GSH) is part of an integrated antioxidant system that protects cells and tissues from oxidative damage. Oxidative stress can result from exposure to excessive amounts of endogenous and exogenous electrophiles. Until recently, animal and cell model systems used to investigate the role of GSH in disease processes had employed chemical agents that deplete cellular GSH by inhibiting GSH synthesis or by reacting chemically with GSH. Such models have proven useful, but questions concerning nonspecific effects of such chemicals remain. Recently, our laboratories and others have developed mouse models with genetic deficiencies in enzymes of the GSH biosynthetic pathway. This review focuses on the regulation of GSH homeostasis and, specifically, the new GSH-deficient mouse models that have been developed. These models will improve our understanding of the role of GSH in animal and human diseases.
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Affiliation(s)
- Timothy P Dalton
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, 123 East Shields Street, P.O. Box 670056, Cincinnati, OH 45267-0056, USA.
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Pardo A, Ruiz V, Arreola JL, Ramírez R, Cisneros-Lira J, Gaxiola M, Barrios R, Kala SV, Lieberman MW, Selman M. Bleomycin-induced pulmonary fibrosis is attenuated in gamma-glutamyl transpeptidase-deficient mice. Am J Respir Crit Care Med 2003; 167:925-32. [PMID: 12468440 DOI: 10.1164/rccm.200209-1007oc] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To investigate repair mechanisms in bleomycin-induced pulmonary fibrosis, we used mice deficient in gamma-glutamyl transpeptidase (GGT-/-), a key enzyme in glutathione (GSH) and cysteine metabolism. Seventy-two hours after bleomycin (0.03 U/g), GGT-/- mice displayed a different inflammatory response to wild-type mice as judged by a near absence of neutrophils in lung tissue and bronchoalveolar lavage and a less pronounced rise in matrix metalloproteinase-9. Inflammation in GGT-/- mice consisted mainly of lymphocytes and macrophages. At 1 month, lungs from bleomycin-treated GGT-/- mice exhibited minimal areas of fibrosis compared with wild-type mice(light microscopy fibrosis index: 510 +/- 756 versus 1975 +/- 817, p < 0.01). Lung collagen content revealed a significant increase in bleomycin-treated wild-type (15.1 +/- 3.8 versus 8.5 +/- 0.7 microg hydroxy(OH)-proline/mg dry weight, p < 0.01) but not in GGT-/- (10.4 +/- 1.7 versus 8.8 +/- 0.8). Control lungs from GGT-/- showed a significant reduction of cysteine (0.03 +/- 0.005 versus 0.055 +/- 0.001, p < 0.02) and GSH levels (1.24 +/- 0.055 versus 1.79 +/- 0.065, p < 0.002). These values decreased after 72 hours of bleomycin in both GGT-/- and wild-type but reached their respective control values after 1 month. Supplementation with N-acetyl cysteine partially ameliorated the effects of GGT deficiency. These findings suggest that increased neutrophils and matrix metalloproteinase-9 during the early inflammatory response and adequate thiol reserves are key elements in the fibrotic response after bleomycin-induced pulmonary injury.
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Affiliation(s)
- Annie Pardo
- Instituto Nacional de Enfermedades Respiratorias, Tlalpan 4502, Col. Sección XVI, México DF, CP 14080, México
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Han B, Luo G, Shi ZZ, Barrios R, Atwood D, Liu W, Habib GM, Sifers RN, Corry DB, Lieberman MW. Gamma-glutamyl leukotrienase, a novel endothelial membrane protein, is specifically responsible for leukotriene D(4) formation in vivo. THE AMERICAN JOURNAL OF PATHOLOGY 2002; 161:481-90. [PMID: 12163373 PMCID: PMC1850737 DOI: 10.1016/s0002-9440(10)64204-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/29/2002] [Indexed: 10/18/2022]
Abstract
The metabolism of cysteinyl leukotrienes in vivo and the pathophysiological effects of individual cysteinyl leukotrienes are primarily unknown. Recently we identified an additional member of the gamma-glutamyl transpeptidase (GGT) family, gamma-glutamyl leukotrienase (GGL), and developed mice deficient in this enzyme. Here we show that in vivo GGL, and not GGT as previously believed, is primarily responsible for conversion of leukotriene C(4) to leukotriene D(4), the most potent of the cysteinyl leukotrienes and the immediate precursor of leukotriene E(4). GGL is a glycoprotein consisting of two polypeptide chains encoded by one gene and is attached at the amino terminus of the heavy chain to endothelial cell membranes. In mice it localizes to capillaries and sinusoids in most organs and in lung to larger vessels as well. In contrast to wild-type and GGT-deficient mice, GGL-deficient mice do not form leukotriene D(4) in vivo either in blood when exogenous leukotriene C(4) is administered intravenously or in bronchoalveolar lavage fluid of Aspergillus fumigatus extract-induced experimental asthma. Further, GGL-deficient mice show leukotriene C(4) accumulation and significantly more airway hyperreponsiveness than wild-type mice in the experimental asthma, and induction of asthma results in increased GGL protein levels and enzymatic activity. Thus GGL plays an important role in leukotriene D(4) synthesis in vivo and in inflammatory processes.
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Affiliation(s)
- Bing Han
- Department of Pathology, Baylor College of Medicine, Houston, Texas 77030, USA
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