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Horio Y, Isegawa Y, Shichiri M. Daidzein phosphorylates and activates 5-lipoxygenase via the MEK/ERK pathway: a mechanism for inducing the production of 5-lipoxygenase metabolite that inhibit influenza virus intracellular replication. J Nutr Biochem 2023; 114:109276. [PMID: 36682398 DOI: 10.1016/j.jnutbio.2023.109276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 12/01/2022] [Accepted: 01/13/2023] [Indexed: 01/22/2023]
Abstract
We previously reported that the soy isoflavone daidzein (Dz) suppresses the intracellular replication of influenza virus and that arachidonic acid-derived oxidation product via lipid oxidase 5-lipoxygenase (5-LOX) is involved in its antiviral effect. The activation of 5-LOX by Dz triggers anti-influenza activity; however, the mechanism of activation of 5-LOX remains unclear. Therefore, in this study, we aimed to clarify the activation mechanism using human monocyte-derived THP-1 cells differentiated using phorbol 12-myristate 13-acetate. THP-1 cells expressed 5-LOX endogenously and Dz did not induce 5-LOX expression. However, 8 h after treatment with Dz, the amount of 5-hydroxyeicosatetraenoic acid (5-HETE), an arachidonic acid oxidation product via 5-LOX, increased significantly suggesting that the enzyme is activated regardless of changes in 5-LOX protein levels. Intracellular Ca2+ content, ATP concentration, 5-LOX protein phosphorylation, and 5-LOX intracellular localization are known 5-LOX activation factors. The intracellular Ca2+ and ATP concentrations were not affected by Dz treatment. The enzymatic activity of 5-LOX is regulated by the phosphorylation of three serine residues and four tyrosine residues. Pretreatment with inhibitors of each kinase revealed that Dz-induced 5-HETE production was suppressed by the MEK/ERK inhibitor. 5-LOX in which the Ser663 residue was phosphorylated was found to be increased in the nuclear fraction of Dz-treated THP-1 cells. Furthermore, immunocytochemistry showed that 5-LOX translocates to the nuclear envelope following Dz treatment. These results indicate that Dz activates 5-LOX by phosphorylating Ser663 via the MEK/ERK pathway. Thus, these results demonstrate that Dz exerts anti-influenza virus activity via the MEK/ERK signal transduction pathway.
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Affiliation(s)
- Yuka Horio
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, Japan; Department of Food Sciences and Nutrition, Mukogawa Women's University, Nishinomiya, Hyogo, Japan
| | - Yuji Isegawa
- Department of Food Sciences and Nutrition, Mukogawa Women's University, Nishinomiya, Hyogo, Japan.
| | - Mototada Shichiri
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, Japan.
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2
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Korbecki J, Rębacz-Maron E, Kupnicka P, Chlubek D, Baranowska-Bosiacka I. Synthesis and Significance of Arachidonic Acid, a Substrate for Cyclooxygenases, Lipoxygenases, and Cytochrome P450 Pathways in the Tumorigenesis of Glioblastoma Multiforme, Including a Pan-Cancer Comparative Analysis. Cancers (Basel) 2023; 15:cancers15030946. [PMID: 36765904 PMCID: PMC9913267 DOI: 10.3390/cancers15030946] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/25/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Glioblastoma multiforme (GBM) is one of the most aggressive gliomas. New and more effective therapeutic approaches are being sought based on studies of the various mechanisms of GBM tumorigenesis, including the synthesis and metabolism of arachidonic acid (ARA), an omega-6 polyunsaturated fatty acid (PUFA). PubMed, GEPIA, and the transcriptomics analysis carried out by Seifert et al. were used in writing this paper. In this paper, we discuss in detail the biosynthesis of this acid in GBM tumors, with a special focus on certain enzymes: fatty acid desaturase (FADS)1, FADS2, and elongation of long-chain fatty acids family member 5 (ELOVL5). We also discuss ARA metabolism, particularly its release from cell membrane phospholipids by phospholipase A2 (cPLA2, iPLA2, and sPLA2) and its processing by cyclooxygenases (COX-1 and COX-2), lipoxygenases (5-LOX, 12-LOX, 15-LOX-1, and 15-LOX-2), and cytochrome P450. Next, we discuss the significance of lipid mediators synthesized from ARA in GBM cancer processes, including prostaglandins (PGE2, PGD2, and 15-deoxy-Δ12,14-PGJ2 (15d-PGJ2)), thromboxane A2 (TxA2), oxo-eicosatetraenoic acids, leukotrienes (LTB4, LTC4, LTD4, and LTE4), lipoxins, and many others. These lipid mediators can increase the proliferation of GBM cancer cells, cause angiogenesis, inhibit the anti-tumor response of the immune system, and be responsible for resistance to treatment.
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Affiliation(s)
- Jan Korbecki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Ewa Rębacz-Maron
- Department of Ecology and Anthropology, Institute of Biology, University of Szczecin, Wąska 13, 71-415 Szczecin, Poland
| | - Patrycja Kupnicka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
- Correspondence: ; Tel.: +48-914-661-515
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3
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Male Knock-in Mice Expressing an Arachidonic Acid Lipoxygenase 15B (Alox15B) with Humanized Reaction Specificity Are Prematurely Growth Arrested When Aging. Biomedicines 2022; 10:biomedicines10061379. [PMID: 35740398 PMCID: PMC9220125 DOI: 10.3390/biomedicines10061379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 01/09/2023] Open
Abstract
Mammalian arachidonic acid lipoxygenases (ALOXs) have been implicated in cell differentiation and in the pathogenesis of inflammation. The mouse genome involves seven functional Alox genes and the encoded enzymes share a high degree of amino acid conservation with their human orthologs. There are, however, functional differences between mouse and human ALOX orthologs. Human ALOX15B oxygenates arachidonic acid exclusively to its 15-hydroperoxy derivative (15S-HpETE), whereas 8S-HpETE is dominantly formed by mouse Alox15b. The structural basis for this functional difference has been explored and in vitro mutagenesis humanized the reaction specificity of the mouse enzyme. To explore whether this mutagenesis strategy may also humanize the reaction specificity of mouse Alox15b in vivo, we created Alox15b knock-in mice expressing the arachidonic acid 15-lipoxygenating Tyr603Asp+His604Val double mutant instead of the 8-lipoxygenating wildtype enzyme. These mice are fertile, display slightly modified plasma oxylipidomes and develop normally up to an age of 24 weeks. At later developmental stages, male Alox15b-KI mice gain significantly less body weight than outbred wildtype controls, but this effect was not observed for female individuals. To explore the possible reasons for the observed gender-specific growth arrest, we determined the basic hematological parameters and found that aged male Alox15b-KI mice exhibited significantly attenuated red blood cell parameters (erythrocyte counts, hematocrit, hemoglobin). Here again, these differences were not observed in female individuals. These data suggest that humanization of the reaction specificity of mouse Alox15b impairs the functionality of the hematopoietic system in males, which is paralleled by a premature growth arrest.
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4
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Heydeck D, Reisch F, Schäfer M, Kakularam KR, Roigas SA, Stehling S, Püschel GP, Kuhn H. The Reaction Specificity of Mammalian ALOX15 Orthologs is Changed During Late Primate Evolution and These Alterations Might Offer Evolutionary Advantages for Hominidae. Front Cell Dev Biol 2022; 10:871585. [PMID: 35531094 PMCID: PMC9068934 DOI: 10.3389/fcell.2022.871585] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/01/2022] [Indexed: 01/03/2023] Open
Abstract
Arachidonic acid lipoxygenases (ALOXs) have been implicated in the immune response of mammals. The reaction specificity of these enzymes is decisive for their biological functions and ALOX classification is based on this enzyme property. Comparing the amino acid sequences and the functional properties of selected mammalian ALOX15 orthologs we previously hypothesized that the reaction specificity of these enzymes can be predicted based on their amino acid sequences (Triad Concept) and that mammals, which are ranked in evolution below gibbons, express arachidonic acid 12-lipoxygenating ALOX15 orthologs. In contrast, Hominidae involving the great apes and humans possess 15-lipoxygenating enzymes (Evolutionary Hypothesis). These two hypotheses were based on sequence data of some 60 mammalian ALOX15 orthologs and about half of them were functionally characterized. Here, we compared the ALOX15 sequences of 152 mammals representing all major mammalian subclades expressed 44 novel ALOX15 orthologs and performed extensive mutagenesis studies of their triad determinants. We found that ALOX15 genes are absent in extant Prototheria but that corresponding enzymes frequently occur in Metatheria and Eutheria. More than 90% of them catalyze arachidonic acid 12-lipoxygenation and the Triad Concept is applicable to all of them. Mammals ranked in evolution above gibbons express arachidonic acid 15-lipoxygenating ALOX15 orthologs but enzymes with similar specificity are only present in less than 5% of mammals ranked below gibbons. This data suggests that ALOX15 orthologs have been introduced during Prototheria-Metatheria transition and put the Triad Concept and the Evolutionary Hypothesis on a much broader and more reliable experimental basis.
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Affiliation(s)
- Dagmar Heydeck
- Department of Biochemistry, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
- *Correspondence: Dagmar Heydeck,
| | - Florian Reisch
- Department of Biochemistry, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
- Institute for Nutritional Sciences, University Potsdam, Potsdam, Germany
| | - Marjann Schäfer
- Department of Biochemistry, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
- Institute for Nutritional Sciences, University Potsdam, Potsdam, Germany
| | - Kumar R. Kakularam
- Department of Biochemistry, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Sophie A. Roigas
- Department of Biochemistry, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Sabine Stehling
- Department of Biochemistry, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Gerhard P. Püschel
- Institute for Nutritional Sciences, University Potsdam, Potsdam, Germany
| | - Hartmut Kuhn
- Department of Biochemistry, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
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5
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Biringer RG. The enzymology of human eicosanoid pathways: the lipoxygenase branches. Mol Biol Rep 2020; 47:7189-7207. [PMID: 32748021 DOI: 10.1007/s11033-020-05698-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/26/2020] [Indexed: 12/16/2022]
Abstract
Eicosanoids are short-lived derivatives of polyunsaturated fatty acids that serve as autocrine and paracrine signaling molecules. They are involved numerous biological processes of both the well state and disease states. A thorough understanding of the progression the disease state and homeostasis of the well state requires a complete evaluation of the systems involved. This review examines the enzymology for the enzymes involved in the production of eicosanoids along the lipoxygenase branches of the eicosanoid pathways with particular emphasis on those derived from arachidonic acid. The enzymatic parameters, protocols to measure them, and proposed catalytic mechanisms are presented in detail.
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Affiliation(s)
- Roger Gregory Biringer
- College of Osteopathic Medicine, Lake Erie College of Osteopathic Medicine, Bradenton, FL, 34211, USA.
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6
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Reisch F, Kakularam KR, Stehling S, Heydeck D, Kuhn H. Eicosanoid biosynthesis in marine mammals. FEBS J 2020; 288:1387-1406. [PMID: 32627384 DOI: 10.1111/febs.15469] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 05/19/2020] [Accepted: 06/22/2020] [Indexed: 01/09/2023]
Abstract
After 300 million years of evolution, the first land-living mammals reentered the marine environment some 50 million years ago. The driving forces for this dramatic lifestyle change are still a matter of discussion but the struggle for food resources and the opportunity to escape predators probably contributed. Reentering the oceans requires metabolic adaption putting evolutionary pressure on a number of genes. To explore whether eicosanoid signaling has been part of this adaptive response, we first explored whether the genomes of marine mammals involve functional genes encoding for key enzymes of eicosanoid biosynthesis. Cyclooxygenase (COX) and lipoxygenase (ALOX) genes are present in the genome of all marine mammals tested. Interestingly, ALOX12B, which has been implicated in skin development of land-living mammals, is lacking in whales and dolphins and genes encoding for its sister enzyme (ALOXE3) involve premature stop codons and/or frameshifting point mutations, which interrupt the open reading frames. ALOX15 orthologs have been detected in all marine mammals, and the recombinant enzymes exhibit similar catalytic properties as those of land-living species. All marine mammals express arachidonic acid 12-lipoxygenating ALOX15 orthologs, and these data are consistent with the Evolutionary Hypothesis of ALOX15 specificity. These enzymes exhibit membrane oxygenase activity and introduction of big amino acids at the triad positions altered the reaction specificity in favor of arachidonic acid 15-lipoxygenation. Thus, the ALOX15 orthologs of marine mammals follow the Triad concept explaining their catalytic specificity.
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Affiliation(s)
- Florian Reisch
- Institute of Biochemistry, Charité - University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Berlin, Germany
| | - Kumar Reddy Kakularam
- Institute of Biochemistry, Charité - University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Berlin, Germany
| | - Sabine Stehling
- Institute of Biochemistry, Charité - University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Berlin, Germany
| | - Dagmar Heydeck
- Institute of Biochemistry, Charité - University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Berlin, Germany
| | - Hartmut Kuhn
- Institute of Biochemistry, Charité - University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Berlin, Germany
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7
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Hajeyah AA, Griffiths WJ, Wang Y, Finch AJ, O’Donnell VB. The Biosynthesis of Enzymatically Oxidized Lipids. Front Endocrinol (Lausanne) 2020; 11:591819. [PMID: 33329396 PMCID: PMC7711093 DOI: 10.3389/fendo.2020.591819] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 12/14/2022] Open
Abstract
Enzymatically oxidized lipids are a specific group of biomolecules that function as key signaling mediators and hormones, regulating various cellular and physiological processes from metabolism and cell death to inflammation and the immune response. They are broadly categorized as either polyunsaturated fatty acid (PUFA) containing (free acid oxygenated PUFA "oxylipins", endocannabinoids, oxidized phospholipids) or cholesterol derivatives (oxysterols, steroid hormones, and bile acids). Their biosynthesis is accomplished by families of enzymes that include lipoxygenases (LOX), cyclooxygenases (COX), cytochrome P450s (CYP), and aldo-keto reductases (AKR). In contrast, non-enzymatically oxidized lipids are produced by uncontrolled oxidation and are broadly considered to be harmful. Here, we provide an overview of the biochemistry and enzymology of LOXs, COXs, CYPs, and AKRs in humans. Next, we present biosynthetic pathways for oxylipins, oxidized phospholipids, oxysterols, bile acids and steroid hormones. Last, we address gaps in knowledge and suggest directions for future work.
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Affiliation(s)
- Ali A. Hajeyah
- Systems Immunity Research Institute and Division of Infection and Immunity, Cardiff University, Cardiff, United Kingdom
- *Correspondence: Ali A. Hajeyah,
| | - William J. Griffiths
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Yuqin Wang
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Andrew J. Finch
- Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Valerie B. O’Donnell
- Systems Immunity Research Institute and Division of Infection and Immunity, Cardiff University, Cardiff, United Kingdom
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8
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Higgins CB, Zhang Y, Mayer AL, Fujiwara H, Stothard AI, Graham MJ, Swarts BM, DeBosch BJ. Hepatocyte ALOXE3 is induced during adaptive fasting and enhances insulin sensitivity by activating hepatic PPARγ. JCI Insight 2018; 3:120794. [PMID: 30135298 PMCID: PMC6141168 DOI: 10.1172/jci.insight.120794] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/10/2018] [Indexed: 12/12/2022] Open
Abstract
The hepatic glucose fasting response is gaining traction as a therapeutic pathway to enhance hepatic and whole-host metabolism. However, the mechanisms underlying these metabolic effects remain unclear. Here, we demonstrate the epidermal-type lipoxygenase, eLOX3 (encoded by its gene, Aloxe3), is a potentially novel effector of the therapeutic fasting response. We show that Aloxe3 is activated during fasting, glucose withdrawal, or trehalose/trehalose analogue treatment. Hepatocyte-specific Aloxe3 expression reduced weight gain and hepatic steatosis in diet-induced and genetically obese (db/db) mouse models. Aloxe3 expression, moreover, enhanced basal thermogenesis and abrogated insulin resistance in db/db diabetic mice. Targeted metabolomics demonstrated accumulation of the PPARγ ligand 12-KETE in hepatocytes overexpressing Aloxe3. Strikingly, PPARγ inhibition reversed hepatic Aloxe3–mediated insulin sensitization, suppression of hepatocellular ATP production and oxygen consumption, and gene induction of PPARγ coactivator-1α (PGC1α) expression. Moreover, hepatocyte-specific PPARγ deletion reversed the therapeutic effect of hepatic Aloxe3 expression on diet-induced insulin intolerance. Aloxe3 is, therefore, a potentially novel effector of the hepatocellular fasting response that leverages both PPARγ-mediated and pleiotropic effects to augment hepatic and whole-host metabolism, and it is, thus, a promising target to ameliorate metabolic disease. The lipoxygenase ALOXE3 is an effector of the hepatic fasting response that improves insulin sensitivity by activating hepatic PPARγ.
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Affiliation(s)
| | | | | | - Hideji Fujiwara
- Department of Medicine, Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alicyn I Stothard
- Department of Chemistry & Biochemistry, Central Michigan University, Mt. Pleasant, Michigan, USA
| | | | - Benjamin M Swarts
- Department of Chemistry & Biochemistry, Central Michigan University, Mt. Pleasant, Michigan, USA
| | - Brian J DeBosch
- Department of Pediatrics and.,Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Kalms J, Banthiya S, Galemou Yoga E, Hamberg M, Holzhutter HG, Kuhn H, Scheerer P. The crystal structure of Pseudomonas aeruginosa lipoxygenase Ala420Gly mutant explains the improved oxygen affinity and the altered reaction specificity. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:463-473. [PMID: 28093240 DOI: 10.1016/j.bbalip.2017.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/03/2017] [Accepted: 01/12/2017] [Indexed: 12/30/2022]
Abstract
Secreted LOX from Pseudomonas aeruginosa (PA-LOX) has previously been identified as arachidonic acid 15S-lipoxygenating enzyme. Here we report that the substitution of Ala420Gly in PA-LOX leads to an enzyme variant with pronounced dual specificity favoring arachidonic acid 11R-oxygenation. When compared with other LOX-isoforms the molecular oxygen affinity of wild-type PA-LOX is 1-2 orders of magnitude lower (Km O2 of 0.4mM) but Ala420Gly exchange improved the molecular oxygen affinity (Km O2 of 0.2mM). Experiments with stereo-specifically deuterated linoleic acid indicated that the formation of both 13S- and 9R-HpODE involves abstraction of the proS-hydrogen from C11 of the fatty acid backbone. To explore the structural basis for the observed functional changes (altered specificity, improved molecular oxygen affinity) we solved the crystal structure of the Ala420Gly mutant of PA-LOX at 1.8Å resolution and compared it with the wild-type enzyme. Modeling of fatty acid alignment at the catalytic center suggested that in the wild-type enzyme dioxygen is directed to C15 of arachidonic acid by a protein tunnel, which interconnects the catalytic center with the protein surface. Ala420Gly exchange redirects intra-enzyme O2 diffusion by bifurcating this tunnel so that C11 of arachidonic acid also becomes accessible for O2 insertion.
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Affiliation(s)
- Jacqueline Kalms
- Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Swathi Banthiya
- Institute for Biochemistry (CC2), Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Etienne Galemou Yoga
- Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Mats Hamberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Hermann-Georg Holzhutter
- Institute for Biochemistry (CC2), Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Hartmut Kuhn
- Institute for Biochemistry (CC2), Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany.
| | - Patrick Scheerer
- Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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10
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Ivanov I, Kuhn H, Heydeck D. Structural and functional biology of arachidonic acid 15-lipoxygenase-1 (ALOX15). Gene 2015; 573:1-32. [PMID: 26216303 PMCID: PMC6728142 DOI: 10.1016/j.gene.2015.07.073] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/26/2015] [Accepted: 07/21/2015] [Indexed: 12/14/2022]
Abstract
Lipoxygenases (LOX) form a family of lipid peroxidizing enzymes, which have been implicated in a number of physiological processes and in the pathogenesis of inflammatory, hyperproliferative and neurodegenerative diseases. They occur in two of the three domains of terrestrial life (bacteria, eucarya) and the human genome involves six functional LOX genes, which encode for six different LOX isoforms. One of these isoforms is ALOX15, which has first been described in rabbits in 1974 as enzyme capable of oxidizing membrane phospholipids during the maturational breakdown of mitochondria in immature red blood cells. During the following decades ALOX15 has extensively been characterized and its biological functions have been studied in a number of cellular in vitro systems as well as in various whole animal disease models. This review is aimed at summarizing the current knowledge on the protein-chemical, molecular biological and enzymatic properties of ALOX15 in various species (human, mouse, rabbit, rat) as well as its implication in cellular physiology and in the pathogenesis of various diseases.
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Affiliation(s)
- Igor Ivanov
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Hartmut Kuhn
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Dagmar Heydeck
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
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11
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Mashima R, Okuyama T. The role of lipoxygenases in pathophysiology; new insights and future perspectives. Redox Biol 2015; 6:297-310. [PMID: 26298204 PMCID: PMC4556770 DOI: 10.1016/j.redox.2015.08.006] [Citation(s) in RCA: 257] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/04/2015] [Accepted: 08/04/2015] [Indexed: 12/21/2022] Open
Abstract
Lipoxygenases (LOXs) are dioxygenases that catalyze the formation of corresponding hydroperoxides from polyunsaturated fatty acids such as linoleic acid and arachidonic acid. LOX enzymes are expressed in immune, epithelial, and tumor cells that display a variety of physiological functions, including inflammation, skin disorder, and tumorigenesis. In the humans and mice, six LOX isoforms have been known. 15-LOX, a prototypical enzyme originally found in reticulocytes shares the similarity of amino acid sequence as well as the biochemical property to plant LOX enzymes. 15-LOX-2, which is expressed in epithelial cells and leukocytes, has different substrate specificity in the humans and mice, therefore, the role of them in mammals has not been established. 12-LOX is an isoform expressed in epithelial cells and myeloid cells including platelets. Many mutations in this isoform are found in epithelial cancers, suggesting a potential link between 12-LOX and tumorigenesis. 12R-LOX can be found in the epithelial cells of the skin. Defects in this gene result in ichthyosis, a cutaneous disorder characterized by pathophysiologically dried skin due to abnormal loss of water from its epithelial cell layer. Similarly, eLOX-3, which is also expressed in the skin epithelial cells acting downstream 12R-LOX, is another causative factor for ichthyosis. 5-LOX is a distinct isoform playing an important role in asthma and inflammation. This isoform causes the constriction of bronchioles in response to cysteinyl leukotrienes such as LTC4, thus leading to asthma. It also induces neutrophilic inflammation by its recruitment in response to LTB4. Importantly, 5-LOX activity is strictly regulated by 5-LOX activating protein (FLAP) though the distribution of 5-LOX in the nucleus. Currently, pharmacological drugs targeting FLAP are actively developing. This review summarized these functions of LOX enzymes under pathophysiological conditions in mammals.
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Affiliation(s)
- Ryuichi Mashima
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Ohkura, Setagaya-ku, Tokyo 157-8535, Japan.
| | - Torayuki Okuyama
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Ohkura, Setagaya-ku, Tokyo 157-8535, Japan
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12
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Horn T, Adel S, Schumann R, Sur S, Kakularam KR, Polamarasetty A, Redanna P, Kuhn H, Heydeck D. Evolutionary aspects of lipoxygenases and genetic diversity of human leukotriene signaling. Prog Lipid Res 2014; 57:13-39. [PMID: 25435097 PMCID: PMC7112624 DOI: 10.1016/j.plipres.2014.11.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/17/2014] [Accepted: 11/19/2014] [Indexed: 12/14/2022]
Abstract
Leukotrienes are pro-inflammatory lipid mediators, which are biosynthesized via the lipoxygenase pathway of the arachidonic acid cascade. Lipoxygenases form a family of lipid peroxidizing enzymes and human lipoxygenase isoforms have been implicated in the pathogenesis of inflammatory, hyperproliferative (cancer) and neurodegenerative diseases. Lipoxygenases are not restricted to humans but also occur in a large number of pro- and eucaryotic organisms. Lipoxygenase-like sequences have been identified in the three domains of life (bacteria, archaea, eucarya) but because of lacking functional data the occurrence of catalytically active lipoxygenases in archaea still remains an open question. Although the physiological and/or pathophysiological functions of various lipoxygenase isoforms have been studied throughout the last three decades there is no unifying concept for the biological importance of these enzymes. In this review we are summarizing the current knowledge on the distribution of lipoxygenases in living single and multicellular organisms with particular emphasis to higher vertebrates and will also focus on the genetic diversity of enzymes and receptors involved in human leukotriene signaling.
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Affiliation(s)
- Thomas Horn
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany; Department of Chemistry and Biochemistry, University of California - Santa Cruz, 1156 High Street, 95064 Santa Cruz, USA
| | - Susan Adel
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Ralf Schumann
- Institute of Microbiology, Charité - University Medicine Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Saubashya Sur
- Institute of Microbiology, Charité - University Medicine Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Kumar Reddy Kakularam
- Department of Animal Sciences, School of Life Science, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Aparoy Polamarasetty
- School of Life Sciences, University of Himachal Pradesh, Dharamshala, Himachal Pradesh 176215, India
| | - Pallu Redanna
- Department of Animal Sciences, School of Life Science, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India; National Institute of Animal Biotechnology, Miyapur, Hyderabad 500049, Telangana, India
| | - Hartmut Kuhn
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Dagmar Heydeck
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
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Rosenberger S, Dick A, Latzko S, Hausser I, Stark HJ, Rauh M, Schneider H, Krieg P. A mouse organotypic tissue culture model for autosomal recessive congenital ichthyosis. Br J Dermatol 2014; 171:1347-57. [PMID: 25078898 DOI: 10.1111/bjd.13308] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2014] [Indexed: 12/31/2022]
Abstract
BACKGROUND Autosomal recessive congenital ichthyoses (ARCIs) are keratinization disorders caused by impaired skin barrier function. Mutations in the genes encoding the lipoxygenases 12R-LOX and eLOX-3 are the second most common cause of ARCIs. In recent years, human skin equivalents recapitulating the ARCI phenotype have been established. OBJECTIVES To develop a murine organotypic tissue culture model for ARCI. METHODS Epidermal keratinocytes were isolated from newborn 12R-LOX-deficient mice and cocultivated with mouse dermal fibroblasts embedded in a scaffold of native collagen type I. RESULTS With this experimental set-up the keratinocytes formed a well-organized multilayered stratified epithelium resembling skin architecture in vivo. All epidermal layers were present and the keratinocytes within showed the characteristic morphological features. Markers for differentiation and maturation indicated regular epidermal morphogenesis. The major components of epidermal structures were expressed, and were obviously processed and assembled properly. In contrast to their wild-type counterparts, 12R-LOX-deficient skin equivalents showed abnormal vesicular structures in the upper epidermal layers correlating with altered lipid composition and increased transepidermal water loss, comparable with 12R-LOX-deficient mice. CONCLUSIONS The mouse skin equivalents faithfully recapitulate the 12R-LOX-deficient phenotype observed in vivo, classifying them as appropriate in vitro models to study molecular mechanisms involved in the development of ARCI and to evaluate novel therapeutic agents. In contrast to existing human three-dimensional skin models, the generation of these murine models is not constrained by a limited supply of material and does not depend on in vitro expansion and/or genetic manipulations that could result in inadvertent genotypic and phenotypic alterations.
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Affiliation(s)
- S Rosenberger
- Genome Modifications and Carcinogenesis, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, D-69120, Heidelberg, Germany
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14
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Kuhn H, Banthiya S, van Leyen K. Mammalian lipoxygenases and their biological relevance. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:308-30. [PMID: 25316652 DOI: 10.1016/j.bbalip.2014.10.002] [Citation(s) in RCA: 416] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/30/2014] [Accepted: 10/03/2014] [Indexed: 02/07/2023]
Abstract
Lipoxygenases (LOXs) form a heterogeneous class of lipid peroxidizing enzymes, which have been implicated not only in cell proliferation and differentiation but also in the pathogenesis of various diseases with major public health relevance. As other fatty acid dioxygenases LOXs oxidize polyunsaturated fatty acids to their corresponding hydroperoxy derivatives, which are further transformed to bioactive lipid mediators (eicosanoids and related substances). On the other hand, lipoxygenases are key players in the regulation of the cellular redox homeostasis, which is an important element in gene expression regulation. Although the first mammalian lipoxygenases were discovered 40 years ago and although the enzymes have been well characterized with respect to their structural and functional properties the biological roles of the different lipoxygenase isoforms are not completely understood. This review is aimed at summarizing the current knowledge on the physiological roles of different mammalian LOX-isoforms and their patho-physiological function in inflammatory, metabolic, hyperproliferative, neurodegenerative and infectious disorders. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".
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Affiliation(s)
- Hartmut Kuhn
- Institute of Biochemistry, University Medicine Berlin - Charite, Chariteplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Swathi Banthiya
- Institute of Biochemistry, University Medicine Berlin - Charite, Chariteplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Klaus van Leyen
- Neuroprotection Research Laboratory, Department of Radiology, Massachusetts Genrel Hospital and Harvard Medical School, Charlestown, MA, USA
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15
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Blancaflor EB, Kilaru A, Keereetaweep J, Khan BR, Faure L, Chapman KD. N-Acylethanolamines: lipid metabolites with functions in plant growth and development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 79:568-583. [PMID: 24397856 DOI: 10.1111/tpj.12427] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/18/2013] [Accepted: 12/23/2013] [Indexed: 06/03/2023]
Abstract
Twenty years ago, N-acylethanolamines (NAEs) were considered by many lipid chemists to be biological 'artifacts' of tissue damage, and were, at best, thought to be minor lipohilic constituents of various organisms. However, that changed dramatically in 1993, when anandamide, an NAE of arachidonic acid (N-arachidonylethanolamine), was shown to bind to the human cannabinoid receptor (CB1) and activate intracellular signal cascades in mammalian neurons. Now NAEs of various types have been identified in diverse multicellular organisms, in which they display profound biological effects. Although targets of NAEs are still being uncovered, and probably vary among eukaryotic species, there appears to be remarkable conservation of the machinery that metabolizes these bioactive fatty acid conjugates of ethanolamine. This review focuses on the metabolism and functions of NAEs in higher plants, with specific reference to the formation, hydrolysis and oxidation of these potent lipid mediators. The discussion centers mostly on early seedling growth and development, for which NAE metabolism has received the most attention, but also considers other areas of plant development in which NAE metabolism has been implicated. Where appropriate, we indicate cross-kingdom conservation in NAE metabolic pathways and metabolites, and suggest areas where opportunities for further investigation appear most pressing.
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Affiliation(s)
- Elison B Blancaflor
- Plant Biology Division, The Samuel Roberts Noble Foundation Inc., 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
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16
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Muñoz-Garcia A, Thomas CP, Keeney DS, Zheng Y, Brash AR. The importance of the lipoxygenase-hepoxilin pathway in the mammalian epidermal barrier. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1841:401-8. [PMID: 24021977 PMCID: PMC4116325 DOI: 10.1016/j.bbalip.2013.08.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 08/27/2013] [Accepted: 08/30/2013] [Indexed: 01/22/2023]
Abstract
This review covers the background to discovery of the two key lipoxygenases (LOX) involved in epidermal barrier function, 12R-LOX and eLOX3, and our current views on their functioning. In the outer epidermis, their consecutive actions oxidize linoleic acid esterified in ω-hydroxy-ceramide to a hepoxilin-related derivative. The relevant background to hepoxilin and trioxilin biochemistry is briefly reviewed. We outline the evidence that linoleate in the ceramide is the natural substrate of the two LOX enzymes and our proposal for its importance in construction of the epidermal water barrier. Our hypothesis is that the oxidation promotes hydrolysis of the oxidized linoleate moiety from the ceramide. The resulting free ω-hydroxyl of the ω-hydroxyceramide is covalently bound to proteins on the surface of the corneocytes to form the corneocyte lipid envelope, a key barrier component. Understanding the role of the LOX enzymes and their hepoxilin products should provide rational approaches to ameliorative therapy for a number of the congenital ichthyoses involving compromised barrier function. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.
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Affiliation(s)
- Agustí Muñoz-Garcia
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Christopher P Thomas
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Diane S Keeney
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Yuxiang Zheng
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alan R Brash
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Horn T, Reddy Kakularam K, Anton M, Richter C, Reddanna P, Kuhn H. Functional characterization of genetic enzyme variations in human lipoxygenases. Redox Biol 2013; 1:566-77. [PMID: 24282679 PMCID: PMC3840004 DOI: 10.1016/j.redox.2013.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 11/01/2013] [Indexed: 01/09/2023] Open
Abstract
Mammalian lipoxygenases play a role in normal cell development and differentiation but they have also been implicated in the pathogenesis of cardiovascular, hyperproliferative and neurodegenerative diseases. As lipid peroxidizing enzymes they are involved in the regulation of cellular redox homeostasis since they produce lipid hydroperoxides, which serve as an efficient source for free radicals. There are various epidemiological correlation studies relating naturally occurring variations in the six human lipoxygenase genes (SNPs or rare mutations) to the frequency for various diseases in these individuals, but for most of the described variations no functional data are available. Employing a combined bioinformatical and enzymological strategy, which included structural modeling and experimental site-directed mutagenesis, we systematically explored the structural and functional consequences of non-synonymous genetic variations in four different human lipoxygenase genes (ALOX5, ALOX12, ALOX15, and ALOX15B) that have been identified in the human 1000 genome project. Due to a lack of a functional expression system we resigned to analyze the functionality of genetic variations in the hALOX12B and hALOXE3 gene. We found that most of the frequent non-synonymous coding SNPs are located at the enzyme surface and hardly alter the enzyme functionality. In contrast, genetic variations which affect functional important amino acid residues or lead to truncated enzyme variations (nonsense mutations) are usually rare with a global allele frequency<0.1%. This data suggest that there appears to be an evolutionary pressure on the coding regions of the lipoxygenase genes preventing the accumulation of loss-of-function variations in the human population. Non-synonymous coding variations in human lipoxygenases are mostly rare with a global allele frequency <1%. Common ALOX SNPs are mainly localized on the enzyme surface and hardly effect the enzyme functionality. hALOX15B Ala416Asp is a newly discovered loss-of-function mutation in the hALOX gene family while inactivity seems to be caused by severe structural alterations. Our data indicate that there is evolutionary pressure on these redox enzymes preventing the accumulation of loss-of-function variations in the human population. 1000 Genome database is a useful tool to analyze the distribution and functionality of variations in genes of interest.
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Key Words
- 12-H(p)ETE, (5Z,8Z,10E,14Z)-12-hydroperoxyeicosa-5,8,10,14-tetraenoic acid
- 15-H(p)ETE, (5Z,8Z,11Z,13E)-15-hydroperoxyeicosa-5,8,11,13-tetraenoic acid
- 5-H(p)ETE, (6E,8Z,11Z,14Z)-5-hydroperoxyeicosa-6,8,11,14-tetraenoic acid
- 8-H(p)ETE, (5Z,9E,11Z,14Z)-8-hydroperoxyeicosa-5,9,11,14-tetraenoic acid
- ALOX, arachidonate lipoxygenase
- Eicosanoids
- Gene polymorphism
- H(p)ETE, hydroperoxyeicosatetraenoic acid
- HETE, hydroxyeicosatetraenoic acid
- IPTG, Isopropyl-β-D-thiogalactopyranosid
- LOXs, lipoxygenases
- LTA4, 4-[(2S,3S)-3-[(1E,3E,5Z,8Z)-tetradeca-1,3,5,8-tetraen-1-yl]oxiran-2-yl]butanoic acid
- LTB4, 5(S),12(R)-dihydroxy-6,8,10,14-(Z,E,E,Z)-eicosatetraenoic acid
- LTC4, (5S,6R,7E,9E,11Z,14Z)-6-{[(2R)-2-[(4S)-4-amino-4-carboxybutanamido]-2-[(carboxymethyl) carbamoyl]ethyl]sulfanyl}-5-hydroxyeicosa-7,9,11,14-tetraenoic acid
- Leukotrienes
- Lipoxygenases
- SNP
- UTR, untranslated region
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Affiliation(s)
- Thomas Horn
- Institute of Biochemistry, University Medicine Berlin-Charité, Charitéplatz 1, D-10117 Berlin, Germany
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18
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Hoffman P, Rauová D, Bezáková L, Obložinský M, Mikuš P. HPLC method for determination of lipoxygenase positional specific products. J Pharm Biomed Anal 2013; 84:53-8. [DOI: 10.1016/j.jpba.2013.05.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 05/23/2013] [Accepted: 05/24/2013] [Indexed: 11/27/2022]
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19
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Krieg P, Fürstenberger G. The role of lipoxygenases in epidermis. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:390-400. [PMID: 23954555 DOI: 10.1016/j.bbalip.2013.08.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 07/31/2013] [Accepted: 08/05/2013] [Indexed: 12/11/2022]
Abstract
Lipoxygenases (LOX) are key enzymes in the biosynthesis of a variety of highly active oxylipins which act as signaling molecules involved in the regulation of many biological processes. LOX are also able to oxidize complex lipids and modify membrane structures leading to structural changes that play a role in the maturation and terminal differentiation of various cell types. The mammalian skin represents a tissue with highly abundant and diverse LOX metabolism. Individual LOX isozymes are thought to play a role in the modulation of epithelial proliferation and/or differentiation as well as in inflammation, wound healing, inflammatory skin diseases and cancer. Emerging evidence indicates a structural function of a particular LOX pathway in the maintenance of skin permeability barrier. Loss-of-function mutations in the LOX genes ALOX12B and ALOXE3 have been found to represent the second most common cause of autosomal recessive congenital ichthyosis and targeted disruption of the corresponding LOX genes in mice resulted in neonatal death due to a severely impaired permeability barrier function. Recent data indicate that LOX action in barrier function can be traced back to the oxygenation of linoleate-containing ceramides which constitutes an important step in the formation of the corneocyte lipid envelope. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.
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Affiliation(s)
- Peter Krieg
- Genome Modifications and Carcinogenesis, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, D69120 Heidelberg, Germany.
| | - Gerhard Fürstenberger
- Genome Modifications and Carcinogenesis, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, D69120 Heidelberg, Germany
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20
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Kim KR, Oh DK. Production of hydroxy fatty acids by microbial fatty acid-hydroxylation enzymes. Biotechnol Adv 2013; 31:1473-85. [PMID: 23860413 DOI: 10.1016/j.biotechadv.2013.07.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/03/2013] [Accepted: 07/06/2013] [Indexed: 10/26/2022]
Abstract
Hydroxy fatty acids are widely used in chemical, food, and cosmetic industries as starting materials for the synthesis of polymers and as additives for the manufacture of lubricants, emulsifiers, and stabilizers. They have antibiotic, anti-inflammatory, and anticancer activities and therefore can be applied for medicinal uses. Microbial fatty acid-hydroxylation enzymes, including P450, lipoxygenase, hydratase, 12-hydroxylase, and diol synthase, synthesize regio-specific hydroxy fatty acids. In this article, microbial fatty acid-hydroxylation enzymes, with a focus on region-specificity and diversity, are summarized and the production of mono-, di-, and tri-hydroxy fatty acids is introduced. Finally, the production methods of regio-specific and diverse hydroxy fatty acids, such as gene screening, protein engineering, metabolic engineering, and combinatory biosynthesis, are suggested.
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Affiliation(s)
- Kyoung-Rok Kim
- Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-Dong Gwangjin-Gu, Seoul 143-701, Republic of Korea
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21
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Brodhun F, Cristobal-Sarramian A, Zabel S, Newie J, Hamberg M, Feussner I. An iron 13S-lipoxygenase with an α-linolenic acid specific hydroperoxidase activity from Fusarium oxysporum. PLoS One 2013; 8:e64919. [PMID: 23741422 PMCID: PMC3669278 DOI: 10.1371/journal.pone.0064919] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 04/21/2013] [Indexed: 12/03/2022] Open
Abstract
Jasmonates constitute a family of lipid-derived signaling molecules that are abundant in higher plants. The biosynthetic pathway leading to plant jasmonates is initiated by 13-lipoxygenase-catalyzed oxygenation of α-linolenic acid into its 13-hydroperoxide derivative. A number of plant pathogenic fungi (e.g. Fusarium oxysporum) are also capable of producing jasmonates, however, by a yet unknown biosynthetic pathway. In a search for lipoxygenase in F. oxysporum, a reverse genetic approach was used and one of two from the genome predicted lipoxygenases (FoxLOX) was cloned. The enzyme was heterologously expressed in E. coli, purified via affinity chromatography, and its reaction mechanism characterized. FoxLOX was found to be a non-heme iron lipoxygenase, which oxidizes C18-polyunsaturated fatty acids to 13S-hydroperoxy derivatives by an antarafacial reaction mechanism where the bis-allylic hydrogen abstraction is the rate-limiting step. With α-linolenic acid as substrate FoxLOX was found to exhibit a multifunctional activity, because the hydroperoxy derivatives formed are further converted to dihydroxy-, keto-, and epoxy alcohol derivatives.
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Affiliation(s)
- Florian Brodhun
- Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, Department of Plant Biochemistry, Goettingen, Germany
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22
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Jin J, Zheng Y, Brash AR. Demonstration of HNE-related aldehyde formation via lipoxygenase-catalyzed synthesis of a bis-allylic dihydroperoxide intermediate. Chem Res Toxicol 2013; 26:896-903. [PMID: 23668325 DOI: 10.1021/tx4000396] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
One of the proposed pathways to the synthesis of 4-hydroxy-nonenal (HNE) and related aldehydes entails formation of an intermediate bis-allylic fatty acid dihydroperoxide. As a first direct demonstration of such a pathway and proof of principle, herein we show that 8R-lipoxygenase (8R-LOX) catalyzes the enzymatic production of the HNE-like product (11-oxo-8-hydroperoxy-undeca-5,9-dienoic acid) via synthesis of 8,11-dihydroperoxy-eicosa-5,9,12,14-tetraenoic acid intermediate. Incubation of arachidonic acid with 8R-LOX formed initially 8R-hydroperoxy-eicosatetraenoic acid (8R-HPETE), which was further converted to a mixture of products including a prominent HPNE-like enone. A new bis-allylic dihydroperoxide was trapped when the incubation was repeated on ice. Reincubation of this intermediate with 8R-LOX successfully demonstrated its conversion to the enone products, and this reaction was greatly accelerated by coincubation with NDGA, a reductant of the LOX iron. These findings identify a plausible mechanism that could contribute to the production of 4-hydroxy-alkenals in vivo.
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Affiliation(s)
- Jing Jin
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, USA
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23
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Jin J, Zheng Y, Boeglin WE, Brash AR. Biosynthesis, isolation, and NMR analysis of leukotriene A epoxides: substrate chirality as a determinant of the cis or trans epoxide configuration. J Lipid Res 2012; 54:754-761. [PMID: 23242647 DOI: 10.1194/jlr.m033746] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leukotriene (LT)A₄ and closely related allylic epoxides are pivotal intermediates in lipoxygenase (LOX) pathways to bioactive lipid mediators that include the leukotrienes, lipoxins, eoxins, resolvins, and protectins. Although the structure and stereochemistry of the 5-LOX product LTA₄ is established through comparison to synthetic standards, this is the exception, and none of these highly unstable epoxides has been analyzed in detail from enzymatic synthesis. Understanding of the mechanistic basis of the cis or trans epoxide configuration is also limited. To address these issues, we developed methods involving biphasic reaction conditions for the LOX-catalyzed synthesis of LTA epoxides in quantities sufficient for NMR analysis. As proof of concept, human 15-LOX-1 was shown to convert 15S-hydroperoxy-eicosatetraenoic acid (15S-HPETE) to the LTA analog 14S,15S-trans-epoxy-eicosa-5Z,8Z,10E,12E-tetraenoate, confirming the proposed structure of eoxin A₄. Using this methodology we then showed that recombinant Arabidopsis AtLOX1, an arachidonate 5-LOX, converts 5S-HPETE to the trans epoxide LTA₄ and converts 5R-HPETE to the cis epoxide 5-epi-LTA₄, establishing substrate chirality as a determinant of the cis or trans epoxide configuration. The results are reconciled with a mechanism based on a dual role of the LOX nonheme iron in LTA epoxide biosynthesis, providing a rational basis for understanding the stereochemistry of LTA epoxide intermediates in LOX-catalyzed transformations.
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Affiliation(s)
- Jing Jin
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232
| | - Yuxiang Zheng
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232
| | - William E Boeglin
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232
| | - Alan R Brash
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232
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24
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Wennman A, Jernerén F, Hamberg M, Oliw EH. Catalytic convergence of manganese and iron lipoxygenases by replacement of a single amino acid. J Biol Chem 2012; 287:31757-65. [PMID: 22822060 PMCID: PMC3442510 DOI: 10.1074/jbc.m112.364331] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 07/16/2012] [Indexed: 12/24/2022] Open
Abstract
Lipoxygenases (LOXs) contain a hydrophobic substrate channel with the conserved Gly/Ala determinant of regio- and stereospecificity and a conserved Leu residue near the catalytic non-heme iron. Our goal was to study the importance of this region (Gly(332), Leu(336), and Phe(337)) of a lipoxygenase with catalytic manganese (13R-MnLOX). Recombinant 13R-MnLOX oxidizes 18:2n-6 and 18:3n-3 to 13R-, 11(S or R)-, and 9S-hydroperoxy metabolites (∼80-85, 15-20, and 2-3%, respectively) by suprafacial hydrogen abstraction and oxygenation. Replacement of Phe(337) with Ile changed the stereochemistry of the 13-hydroperoxy metabolites of 18:2n-6 and 18:3n-3 (from ∼100% R to 69-74% S) with little effect on regiospecificity. The abstraction of the pro-S hydrogen of 18:2n-6 was retained, suggesting antarafacial hydrogen abstraction and oxygenation. Replacement of Leu(336) with smaller hydrophobic residues (Val, Ala, and Gly) shifted the oxygenation from C-13 toward C-9 with formation of 9S- and 9R-hydroperoxy metabolites of 18:2n-6 and 18:3n-3. Replacement of Gly(332) and Leu(336) with larger hydrophobic residues (G332A and L336F) selectively augmented dehydration of 13R-hydroperoxyoctadeca-9Z,11E,15Z-trienoic acid and increased the oxidation at C-13 of 18:1n-6. We conclude that hydrophobic replacements of Leu(336) can modify the hydroperoxide configurations at C-9 with little effect on the R configuration at C-13 of the 18:2n-6 and 18:3n-3 metabolites. Replacement of Phe(337) with Ile changed the stereospecific oxidation of 18:2n-6 and 18:3n-3 with formation of 13S-hydroperoxides by hydrogen abstraction and oxygenation in analogy with soybean LOX-1.
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Affiliation(s)
- Anneli Wennman
- From the Department of Pharmaceutical Biosciences, Uppsala University, Biomedical Center, SE-751 24 Uppsala, Sweden and
| | - Fredrik Jernerén
- From the Department of Pharmaceutical Biosciences, Uppsala University, Biomedical Center, SE-751 24 Uppsala, Sweden and
| | - Mats Hamberg
- the Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Solna, Sweden
| | - Ernst H. Oliw
- From the Department of Pharmaceutical Biosciences, Uppsala University, Biomedical Center, SE-751 24 Uppsala, Sweden and
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25
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Krieg P, Rosenberger S, de Juanes S, Latzko S, Hou J, Dick A, Kloz U, van der Hoeven F, Hausser I, Esposito I, Rauh M, Schneider H. Aloxe3 knockout mice reveal a function of epidermal lipoxygenase-3 as hepoxilin synthase and its pivotal role in barrier formation. J Invest Dermatol 2012; 133:172-80. [PMID: 22832496 DOI: 10.1038/jid.2012.250] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Loss-of-function mutations in the lipoxygenase (LOX) genes ALOX12B and ALOXE3 are the second most common cause of autosomal recessive congenital ichthyosis. The encoded proteins, 12R-LOX and epidermal LOX-3 (eLOX-3), act in sequence to convert fatty acid substrates via R-hydroperoxides to specific epoxyalcohol derivatives and have been proposed to operate in the same metabolic pathway during epidermal barrier formation. Here, we show that eLOX-3 deficiency in mice results in early postnatal death, associated with similar but somewhat less severe barrier defects and morphological changes than reported earlier for the 12R-LOX-knockout mice. Skin lipid analysis demonstrated that the severity of barrier failure is related to the loss of covalently bound ceramides in both 12R-LOX- and eLOX-3-null mice, confirming a proposed functional linkage of the LOX pathway to ceramide processing and formation of the corneocyte lipid envelope. Furthermore, analysis of free oxygenated fatty acid metabolites revealed strongly reduced levels of hepoxilin metabolites in eLOX-3-deficient epidermis, indicating an additional function of eLOX-3 in mammalian skin as a hepoxilin synthase linked to the 12S-LOX pathway.
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Affiliation(s)
- Peter Krieg
- Genome Modifications and Carcinogenesis, German Cancer Research Center, Heidelberg, Germany.
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26
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Järving R, Lõokene A, Kurg R, Siimon L, Järving I, Samel N. Activation of 11R-Lipoxygenase Is Fully Ca2+-Dependent and Controlled by the Phospholipid Composition of the Target Membrane. Biochemistry 2012; 51:3310-20. [DOI: 10.1021/bi201690z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Reet Järving
- Department
of Chemistry, Tallinn University of Technology, Akadeemia tee 15,
12618 Tallinn, Estonia
| | - Aivar Lõokene
- Department
of Chemistry, Tallinn University of Technology, Akadeemia tee 15,
12618 Tallinn, Estonia
| | - Reet Kurg
- Institute of Technology, University of Tartu, Nooruse St 1, 50411 Tartu, Estonia
| | - Liina Siimon
- Department
of Chemistry, Tallinn University of Technology, Akadeemia tee 15,
12618 Tallinn, Estonia
| | - Ivar Järving
- Department
of Chemistry, Tallinn University of Technology, Akadeemia tee 15,
12618 Tallinn, Estonia
| | - Nigulas Samel
- Department
of Chemistry, Tallinn University of Technology, Akadeemia tee 15,
12618 Tallinn, Estonia
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27
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Jin J, Boeglin WE, Cha JK, Brash AR. 8R-Lipoxygenase-catalyzed synthesis of a prominent cis-epoxyalcohol from dihomo-γ-linolenic acid: a distinctive transformation compared with S-lipoxygenases. J Lipid Res 2011; 53:292-9. [PMID: 22158855 DOI: 10.1194/jlr.m022863] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Conversion of fatty acid hydroperoxides to epoxyalcohols is a well known secondary reaction of lipoxygenases, described for S-specific lipoxygenases forming epoxyalcohols with a trans-epoxide configuration. Here we report on R-specific lipoxygenase synthesis of a cis-epoxyalcohol. Although arachidonic and dihomo-γ-linolenic acids are metabolized by extracts of the Caribbean coral Plexaura homomalla via 8R-lipoxygenase and allene oxide synthase activities, 20:3ω6 forms an additional prominent product, identified using UV, GC-MS, and NMR in comparison to synthetic standards as 8R,9S-cis-epoxy-10S-erythro-hydroxy-eicosa-11Z,14Z-dienoic acid. Both oxygens of (18)O-labeled 8R-hydroperoxide are retained in the product, indicating a hydroperoxide isomerase activity. Recombinant allene oxide synthase formed only allene epoxide from 8R-hydroperoxy-20:3ω6, whereas two different 8R-lipoxygenases selectively produced the epoxyalcohol.A biosynthetic scheme is proposed in which a partial rotation of the reacting intermediate is required to give the observed erythro epoxyalcohol product. This characteristic and the synthesis of cis-epoxy epoxyalcohol may be a feature of R-specific lipoxygenases.
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Affiliation(s)
- Jing Jin
- Department of Pharmacology, and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
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28
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Haeggström JZ, Funk CD. Lipoxygenase and leukotriene pathways: biochemistry, biology, and roles in disease. Chem Rev 2011; 111:5866-98. [PMID: 21936577 DOI: 10.1021/cr200246d] [Citation(s) in RCA: 609] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Jesper Z Haeggström
- Department of Medical Biochemistry and Biophysics, Division of Chemistry 2, Karolinska Institutet, S-171 77 Stockholm, Sweden.
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29
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Jansen C, Hofheinz K, Vogel R, Roffeis J, Anton M, Reddanna P, Kuhn H, Walther M. Stereocontrol of arachidonic acid oxygenation by vertebrate lipoxygenases: newly cloned zebrafish lipoxygenase 1 does not follow the Ala-versus-Gly concept. J Biol Chem 2011; 286:37804-12. [PMID: 21880725 DOI: 10.1074/jbc.m111.259242] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Animal lipoxygenases (LOXs) are classified according to their specificity of arachidonic acid oxygenation, and previous sequence alignments suggested that S-LOXs contain a conserved Ala at a critical position at the active site but R-LOXs carry a Gly instead. Here we cloned, expressed, and characterized a novel LOX isoform from the model vertebrate Danio rerio (zebrafish) that carries a Gly at this critical position, classifying this enzyme as putative arachidonic acid R-LOX. Surprisingly, the almost exclusive arachidonic acid oxygenation product was 12S-H(p)ETE (hydro(pero)xyeicosatetraenoic acid), and extensive mutation around Gly-410 failed to induce R-lipoxygenation. This finding prompted us to explore the importance of the corresponding amino acids in other vertebrate S-LOXs. We found that Ala-to-Gly exchange in human 15-LOX2 and human platelet 12-LOX induced major alterations in the reaction specificity with an increase of specific R-oxygenation products. For mouse 5-LOX and 12/15-LOX from rabbits, men, rhesus monkeys, orangutans, and mice, only minor alterations in the reaction specificity were observed. For these enzymes, S-HETE (hydroxyeicosatetraenoic acid) isomers remained the major oxygenation products, whereas chiral R-HETEs contributed only 10-30% to the total product mixture. Taken together these data indicate that the Ala-versus-Gly concept may not always predict the reaction specificity of vertebrate LOX isoforms.
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Affiliation(s)
- Christian Jansen
- Institute of Biochemistry, University Medicine Berlin-Charité, Monbijoustrasse 2, D-10117 Berlin, Germany
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30
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Schurmann K, Anton M, Ivanov I, Richter C, Kuhn H, Walther M. Molecular basis for the reduced catalytic activity of the naturally occurring T560M mutant of human 12/15-lipoxygenase that has been implicated in coronary artery disease. J Biol Chem 2011; 286:23920-7. [PMID: 21558275 DOI: 10.1074/jbc.m110.211821] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Lipoxygenases have been implicated in cardiovascular disease. A rare single-nucleotide polymorphism causing T560M exchange has recently been described, and this mutation leads to a near null variant of the enzyme encoded for by the ALOX15 gene. When we inspected the three-dimensional structure of the rabbit ortholog, we localized Thr-560 outside the active site and identified a hydrogen bridge between its side chain and Gln-294. This interaction is part of a complex hydrogen bond network that appears to be conserved in other mammalian lipoxygenases. Gln-294 and Asn-287 are key amino acids in this network, and we hypothesized that disturbance of this hydrogen bond system causes the low activity of the T560M mutant. To test this hypothesis, we first mutated Thr-560 to amino acids not capable of forming side chain hydrogen bridges (T560M and T560A) and obtained enzyme variants with strongly reduced catalytic activity. In contrast, enzymatic activity was retained after T560S exchange. Enzyme variants with strongly reduced activity were also obtained when we mutated Gln-294 (binding partner of Thr-560) and Asn-287 (binding partner of Gln-294 and Met-418) to Leu. Basic kinetic characterization of the T560M mutant indicated that the enzyme lacks a kinetic lag phase but is rapidly inactivated. These data suggest that the low catalytic efficiency of the naturally occurring T560M mutant is caused by alterations of a hydrogen bond network interconnecting this residue with active site constituents. Disturbance of this bonding network increases the susceptibility of the enzyme for suicidal inactivation.
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Affiliation(s)
- Kathrin Schurmann
- Institute of Biochemistry, University Medicine Berlin-Charité, D-10117 Berlin, Germany
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31
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Zheng Y, Brash AR. On the role of molecular oxygen in lipoxygenase activation: comparison and contrast of epidermal lipoxygenase-3 with soybean lipoxygenase-1. J Biol Chem 2010; 285:39876-87. [PMID: 20923767 PMCID: PMC3000969 DOI: 10.1074/jbc.m110.180794] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 10/03/2010] [Indexed: 11/06/2022] Open
Abstract
The oxygenation of polyunsaturated fatty acids by lipoxygenases (LOX) is associated with a lag phase during which the resting ferrous enzyme is converted to the active ferric form by reaction with fatty acid hydroperoxide. Epidermal lipoxygenase-3 (eLOX3) is atypical in displaying hydroperoxide isomerase activity with fatty acid hydroperoxides through cycling of the ferrous enzyme. Yet eLOX3 is capable of dioxygenase activity, albeit with a long lag phase and need for high concentrations of hydroperoxide activator. Here, we show that higher O(2) concentration shortens the lag phase in eLOX3, although it reduces the rate of hydroperoxide consumption, effects also associated with an A451G mutation known to affect the disposition of molecular oxygen in the LOX active site. These observations are consistent with a role of O(2) in interrupting hydroperoxide isomerase cycling. Activation of eLOX3, A451G eLOX3, and soybean LOX-1 with 13-hydroperoxy-linoleic acid forms oxygenated end products, which we identified as 9R- and 9S-hydroperoxy-12S,13S-trans-epoxyoctadec-10E-enoic acids. We deduce that activation partly depends on reaction of O(2) with the intermediate of hydroperoxide cleavage, the epoxyallylic radical, giving an epoxyallylic peroxyl radical that does not further react with Fe(III)-OH; instead, it dissociates and leaves the enzyme in the activated free ferric state. eLOX3 differs from soybean LOX-1 in more tightly binding the epoxyallylic radical and having limited access to O(2) within the active site, leading to a deficiency in activation and a dominant hydroperoxide isomerase activity.
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Affiliation(s)
- Yuxiang Zheng
- From the Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Alan R. Brash
- From the Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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