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Mark T Gladwin - One of the best experts on this subject based on the ideXlab platform.
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redox sensor properties of human Cytoglobin allosterically regulate heme pocket reactivity
Free Radical Biology and Medicine, 2021Co-Authors: Anthony W Demartino, Matthew B Amdahl, Jason J Rose, Jesus Tejero, Kaitlin Bocian, Mark T GladwinAbstract:Abstract Cytoglobin is a conserved hemoprotein ubiquitously expressed in mammalian tissues, which conducts electron transfer reactions with proposed signaling functions in nitric oxide (NO) and lipid metabolism. Cytoglobin has an E7 distal histidine (His81), which unlike related globins such as myoglobin and hemoglobin, is in equilibrium between a bound, hexacoordinate state and an unbound, pentacoordinate state. The His81 binding equilibrium appears to be allosterically modulated by the presence of an intramolecular disulfide between two cysteines (Cys38 and Cys83). The formation of this disulfide bridge regulates nitrite reductase activity and lipid binding. Herein, we attempt to clarify the effects of defined thiol oxidation states on small molecule binding of Cytoglobin heme, using cyanide binding to probe the ferric state. Cyanide binding kinetics to wild-type Cytoglobin reveal at least two kinetically distinct subpopulations, depending on thiol oxidation states. Experiments with covalent thiol modification by NEM, glutathione, and amino acid substitutions (C38S, C83S and H81A), indicate that subpopulations ranging from fully reduced thiols, single thiol oxidation, and intramolecular disulfide formation determine heme binding properties by modulating the histidine-heme affinity and ligand binding. The redox modulation of ligand binding is sensitive to physiological levels of hydrogen peroxide, with a functional midpoint redox potential for the native Cytoglobin intramolecular disulfide bond of −189 ± 4 mV, a value within the boundaries of intracellular redox potentials. These results support the hypothesis that Cys38 and Cys83 on Cytoglobin serve as sensitive redox sensors that modulate the Cytoglobin distal heme pocket reactivity and ligand binding.
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abstract 12361 Cytoglobin regulates cilia length function and organ system laterality during development
Circulation, 2019Co-Authors: Elizabeth R Rochon, Mark T Gladwin, Jianmin Xue, Manush Saydmohammed, Michael Tsang, Paola CortiAbstract:Introduction: Cytoglobin is a heme protein known to be expressed at relatively low concentrations in a variety of tissues throughout development and highly conserved in all vertebrates. While cytog...
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the zebrafish cytochrome b5 cytochrome b5 reductase nadh system efficiently reduces Cytoglobins 1 and 2 conserved activity of cytochrome b5 cytochrome b5 reductases during vertebrate evolution
Biochemistry, 2019Co-Authors: Matthew B Amdahl, Courtney Sparacinowatkins, Elin E Petersen, K A Bocian, Stefan Kaliszuk, Anthony W Demartino, Sagarika Tiwari, Jason J Rose, Paola Corti, Mark T GladwinAbstract:: Cytoglobin is a heme protein evolutionarily related to hemoglobin and myoglobin. Cytoglobin is expressed ubiquitously in mammalian tissues; however, its physiological functions are yet unclear. Phylogenetic analyses indicate that the Cytoglobin gene is highly conserved in vertebrate clades, from fish to reptiles, amphibians, birds, and mammals. Most proposed roles for Cytoglobin require the maintenance of a pool of reduced Cytoglobin (FeII). We have shown previously that the human cytochrome b5/cytochrome b5 reductase system, considered a quintessential hemoglobin/myoglobin reductant, can reduce human and zebrafish Cytoglobins ≤250-fold faster than human hemoglobin or myoglobin. It was unclear whether this reduction of zebrafish Cytoglobins by mammalian proteins indicates a conserved pathway through vertebrate evolution. Here, we report the reduction of zebrafish Cytoglobins 1 and 2 by the zebrafish cytochrome b5 reductase and the two zebrafish cytochrome b5 isoforms. In addition, the reducing system also supports reduction of Globin X, a conserved globin in fish and amphibians. Indeed, the zebrafish reducing system can maintain a fully reduced pool for both Cytoglobins, and both cytochrome b5 isoforms can support this process. We determined the P50 for oxygen to be 0.5 Torr for Cytoglobin 1 and 4.4 Torr for Cytoglobin 2 at 25 °C. Thus, even at low oxygen tensions, the reduced Cytoglobins may exist in a predominant oxygen-bound form. Under these conditions, the cytochrome b5/cytochrome b5 reductase system can support a conserved role for Cytoglobins through evolution, providing electrons for redox signaling reactions such as nitric oxide dioxygenation, nitrite reduction, and phospholipid oxidation.
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the zebrafish cytochrome b5 cytochrome b5 reductase nadh system efficiently reduces Cytoglobins 1 and 2 conserved activity of cytochrome b5 cytochrome b5 reductases during vertebrate evolution
Biochemistry, 2019Co-Authors: Matthew B Amdahl, Courtney Sparacinowatkins, Elin E Petersen, Stefan Kaliszuk, Anthony W Demartino, Sagarika Tiwari, Jason J Rose, Paola Corti, Kaitlin Bocian, Mark T GladwinAbstract:Cytoglobin is a heme protein evolutionarily related to hemoglobin and myoglobin. Cytoglobin is expressed ubiquitously in mammalian tissues; however, its physiological functions are yet unclear. Phy...
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interrogating the Cytoglobin binding pocket and thiol redox status with point mutations and chemical probes
Free Radical Biology and Medicine, 2018Co-Authors: Anthony W Demartino, Jesus Tejero, Mark T GladwinAbstract:Cytoglobin (Cygb) is a highly conserved, hexacoordinate heme protein expressed ubiquitously in mammalian tissues. Unlike other commonly found globins (i.e., hemoglobin and myoglobin), Cygb has a bound - but dissociable - proximal histidine that hinders ligand binding and, unlike the common globins, Cygb is not regarded to be closely associated with oxygen transport. The physiological functions of Cygb are still unclear but are thought to include ROS detoxification, lipid peroxidation, and vascular nitric oxide metabolism via hypoxic nitrite reduction and O2-dependent nitric oxide dioxygenation. All of these processes first require dissociation of the distal histidine to generate an active penta-coordinate heme. Further, these processes are likely further modulated by two conserved cysteine residues (Cys38 and Cys83), which can readily generate intermolecular dimeric and intramolecular monomeric disulfide bonds. For instance, formation of the intramolecular monomer greatly increases the nitrite reductase (NiR) activity, suggesting a change in pocket shape resulting in an increase in the rate and frequency the distal histidine dissociates. Predominantly using stopped-flow and kinetic techniques, we are assessing the effect of the redox states of these cysteines via small molecule binding/reaction characterization in both the ferrous and ferric form of the protein, elucidating differences in the binding pocket conformation in various redox environments. These methodologies consequently allow for the assessment of the thiol oxidation state, as different preparations of recombinant Cygbs vary and result in formation of differing cysteine redox states. Chemical modification and point mutations have been used to generate a number of modified Cytoglobins to develop a more complete picture of the effect of the redox states of these cysteines.
Matthew B Amdahl - One of the best experts on this subject based on the ideXlab platform.
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redox sensor properties of human Cytoglobin allosterically regulate heme pocket reactivity
Free Radical Biology and Medicine, 2021Co-Authors: Anthony W Demartino, Matthew B Amdahl, Jason J Rose, Jesus Tejero, Kaitlin Bocian, Mark T GladwinAbstract:Abstract Cytoglobin is a conserved hemoprotein ubiquitously expressed in mammalian tissues, which conducts electron transfer reactions with proposed signaling functions in nitric oxide (NO) and lipid metabolism. Cytoglobin has an E7 distal histidine (His81), which unlike related globins such as myoglobin and hemoglobin, is in equilibrium between a bound, hexacoordinate state and an unbound, pentacoordinate state. The His81 binding equilibrium appears to be allosterically modulated by the presence of an intramolecular disulfide between two cysteines (Cys38 and Cys83). The formation of this disulfide bridge regulates nitrite reductase activity and lipid binding. Herein, we attempt to clarify the effects of defined thiol oxidation states on small molecule binding of Cytoglobin heme, using cyanide binding to probe the ferric state. Cyanide binding kinetics to wild-type Cytoglobin reveal at least two kinetically distinct subpopulations, depending on thiol oxidation states. Experiments with covalent thiol modification by NEM, glutathione, and amino acid substitutions (C38S, C83S and H81A), indicate that subpopulations ranging from fully reduced thiols, single thiol oxidation, and intramolecular disulfide formation determine heme binding properties by modulating the histidine-heme affinity and ligand binding. The redox modulation of ligand binding is sensitive to physiological levels of hydrogen peroxide, with a functional midpoint redox potential for the native Cytoglobin intramolecular disulfide bond of −189 ± 4 mV, a value within the boundaries of intracellular redox potentials. These results support the hypothesis that Cys38 and Cys83 on Cytoglobin serve as sensitive redox sensors that modulate the Cytoglobin distal heme pocket reactivity and ligand binding.
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the zebrafish cytochrome b5 cytochrome b5 reductase nadh system efficiently reduces Cytoglobins 1 and 2 conserved activity of cytochrome b5 cytochrome b5 reductases during vertebrate evolution
Biochemistry, 2019Co-Authors: Matthew B Amdahl, Courtney Sparacinowatkins, Elin E Petersen, K A Bocian, Stefan Kaliszuk, Anthony W Demartino, Sagarika Tiwari, Jason J Rose, Paola Corti, Mark T GladwinAbstract:: Cytoglobin is a heme protein evolutionarily related to hemoglobin and myoglobin. Cytoglobin is expressed ubiquitously in mammalian tissues; however, its physiological functions are yet unclear. Phylogenetic analyses indicate that the Cytoglobin gene is highly conserved in vertebrate clades, from fish to reptiles, amphibians, birds, and mammals. Most proposed roles for Cytoglobin require the maintenance of a pool of reduced Cytoglobin (FeII). We have shown previously that the human cytochrome b5/cytochrome b5 reductase system, considered a quintessential hemoglobin/myoglobin reductant, can reduce human and zebrafish Cytoglobins ≤250-fold faster than human hemoglobin or myoglobin. It was unclear whether this reduction of zebrafish Cytoglobins by mammalian proteins indicates a conserved pathway through vertebrate evolution. Here, we report the reduction of zebrafish Cytoglobins 1 and 2 by the zebrafish cytochrome b5 reductase and the two zebrafish cytochrome b5 isoforms. In addition, the reducing system also supports reduction of Globin X, a conserved globin in fish and amphibians. Indeed, the zebrafish reducing system can maintain a fully reduced pool for both Cytoglobins, and both cytochrome b5 isoforms can support this process. We determined the P50 for oxygen to be 0.5 Torr for Cytoglobin 1 and 4.4 Torr for Cytoglobin 2 at 25 °C. Thus, even at low oxygen tensions, the reduced Cytoglobins may exist in a predominant oxygen-bound form. Under these conditions, the cytochrome b5/cytochrome b5 reductase system can support a conserved role for Cytoglobins through evolution, providing electrons for redox signaling reactions such as nitric oxide dioxygenation, nitrite reduction, and phospholipid oxidation.
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the zebrafish cytochrome b5 cytochrome b5 reductase nadh system efficiently reduces Cytoglobins 1 and 2 conserved activity of cytochrome b5 cytochrome b5 reductases during vertebrate evolution
Biochemistry, 2019Co-Authors: Matthew B Amdahl, Courtney Sparacinowatkins, Elin E Petersen, Stefan Kaliszuk, Anthony W Demartino, Sagarika Tiwari, Jason J Rose, Paola Corti, Kaitlin Bocian, Mark T GladwinAbstract:Cytoglobin is a heme protein evolutionarily related to hemoglobin and myoglobin. Cytoglobin is expressed ubiquitously in mammalian tissues; however, its physiological functions are yet unclear. Phy...
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Cytoglobin at the crossroads of vascular remodeling
Arteriosclerosis Thrombosis and Vascular Biology, 2017Co-Authors: Matthew B Amdahl, Anthony W Demartino, Jesus Tejero, Mark T GladwinAbstract:Since its discovery ≈15 years ago, Cytoglobin has been studied extensively. Because it is found outside the red cell, Cytoglobin is categorized as a nonerythroid globin, along with (in humans) proteins, such as myoglobin, neuroglobin, androglobin, and hemoglobin α. The putative functions of these nonerythroid globins are linked to tissue protection from conditions such as hypoxia, ischemia, and oxidative stress.1 Cytoglobin not only fulfills these functions but also has been related to other roles, including tumor suppression and the regulation of fibrosis in cell and animal models.2–7 Like other heme globins, Cytoglobin can reversibly bind oxygen and other small molecules. The ability of Cytoglobin to store and sense oxygen, as well as its involvement in nitrite and nitric oxide (NO) metabolism, being able to both scavenge NO and produce NO from nitrite, is probably key to its function(s).8,9 However, in spite of significant progress in understanding the structure, localization, and functional characteristics of Cytoglobin, the central physiological roles of this protein have yet to be fully elucidated.10–12 See accompanying article on page 1944 In this issue of Arteriosclerosis, Thrombosis, and Vascular Biology , Jourd’heuil et al13 examine the role of Cytoglobin in controlling apoptosis and vascular remodeling after injury. Cytoglobin seems to be the predominant globin in vessel walls of humans, rats, and …
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efficient reduction of vertebrate Cytoglobins by the cytochrome b5 cytochrome b5 reductase nadh system
Biochemistry, 2017Co-Authors: Matthew B Amdahl, Courtney Sparacinowatkins, Paola Corti, Mark T Gladwin, Jesus TejeroAbstract:Cytoglobin is a heme-containing protein ubiquitous in mammalian tissues. Unlike the evolutionarily related proteins hemoglobin and myoglobin, Cytoglobin shows a six-coordinated heme binding, with the heme iron coordinated by two histidine side chains. Cytoglobin is involved in cytoprotection pathways through yet undefined mechanisms, and it has recently been demonstrated that Cytoglobin has redox signaling properties via nitric oxide (NO) and nitrite metabolism. The reduced, ferrous Cytoglobin can bind oxygen and will react with NO in a dioxygenation reaction to form nitrate, which dampens NO signaling. When deoxygenated, Cytoglobin can bind nitrite and reduce it to NO. This oxidoreductase activity could be catalytic if an effective reduction system exists to regenerate the reduced heme species. The nature of the physiological Cytoglobin reducing system is unknown, although it has been proposed that ascorbate and cytochrome b5 could fulfill this role. Here we describe that physiological concentrations of ...
Sylvia Dewilde - One of the best experts on this subject based on the ideXlab platform.
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the role of Cytoglobin in the plasma treatment of melanoma
Clinical Plasma Medicine, 2018Co-Authors: Joey De Backer, Jamoliddin Razzokov, Dietmar Hammerschmid, Carl Mensch, Naresh Kumar, Annemie Bogaerts, Sylvia DewildeAbstract:Globins are ancient proteins that are present in all kingdoms of life. At the moment, there are 8 different globins known in vertebrates with distinct expression patterns. Human Cytoglobin (CYGB), a member of this globin superfamily, is a hexacoordinated heme-protein that is mostly expressed in fibroblasts and fibroblast-related cells, but is also present in neurons, macrophages, muscles and epithelium. Although globins can have a respiratory function, additional functions such as roles in NO metabolism, signal transduction, lipid metabolism and the detoxification of ROS have been proposed. As a consequence of these different functions and localisations, Cygb probably plays a significant role in different pathological conditions such as fibrosis, neurodegeneration and tumorigenesis. For the latter, CYGB has been proposed to be a candidate tumour-suppressor gene [1] as its downregulation in tumors has been associated with increased cancer cell proliferation and elevated extracellular signalregulated kinase and Akt activation [2]. It has been shown that the highest Cygb expression is seen in melanocytes [3]. Furthermore, melanocyte to melanoma transition has been associated with DNAmethylation induced reduction of Cygb expression. While melanoma is accounting for We have studied the effect of CAP on the cell viability of two melanoma cell lines and on melanocytes and investigated the role of Cygb herin. Furthermore as it is hypothesized that Cygb can act as a ROS regulator/scavanger, the intracellular ROS concentration was measured in the different cell lines. The observed results indicate a correlation between the expression level of Cygb, the intracellular ROS concentration and the sensitivity of the cell line towards CAP treatment. The molecular mechanism of how Cygb exerts its effect is however, unclear. Therefore we have performed spectroscopic and simulation studies to determine the effect of CAP on the structure of Cygb. Hopefully, this investigation of the combined effect of CAP treatment on cell viability and the (possible) role of Cygb as ROS scavenger and its structural effect, may contribute to the characterization of the biochemical pathways underlying the response of melanocytes and melanomas to CAP treatment.
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Cytoglobin conformations and disulfide bond formation
FEBS Journal, 2010Co-Authors: Christophe Lechauve, Brian N. Green, Sylvia Dewilde, Michael C Marden, Luc Moens, Cedric Chauvierre, Chantal Celier, Laurent KigerAbstract:The oligomeric state and kinetics of ligand binding were measured for wild-type Cytoglobin. Cytoglobin has the classical globin fold, with an extension at each extremity of about 20 residues. The extended length of Cytoglobin leads to an ambiguous interpretation of its oligomeric state. Although the hydrodynamic diameter corresponds to that of a dimer, it displays a mass of a single subunit, indicating a monomeric form. Thus, rather than displaying a compact globular form, Cytoglobin behaves hydrodynamically like a tightly packed globin with a greater flexibility of the N- and C-terminal regions. Cytoglobin displays biphasic kinetics after the photolysis of CO, as a result of competition with an internal protein ligand, the E7 distal histidine. An internal disulfide bond may form which modifies the rate of dissociation of the distal histidine and apparently leads to different Cytoglobin conformations, which may affect the observed oxygen affinity by an order of magnitude.
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reactions of ferrous neuroglobin and Cytoglobin with nitrite under anaerobic conditions
Journal of Inorganic Biochemistry, 2008Co-Authors: Morten Gjerning Petersen, Sylvia Dewilde, Angela FagoAbstract:Abstract Recent evidence suggests that the reaction of nitrite with deoxygenated hemoglobin and myoglobin contributes to the generation of nitric oxide and S-nitrosothiols in vivo under conditions of low oxygen availability. We have investigated whether ferrous neuroglobin and Cytoglobin, the two hexacoordinate globins from vertebrates expressed in brain and in a variety of tissues, respectively, also react with nitrite under anaerobic conditions. Using absorption spectroscopy, we find that ferrous neuroglobin and nitrite react with a second-order rate constant similar to that of myoglobin, whereas the ferrous heme of Cytoglobin does not react with nitrite. Deconvolution of absorbance spectra shows that, in the course of the reaction of neuroglobin with nitrite, ferric Fe(III) heme is generated in excess of nitrosyl Fe(II)–NO heme as due to the low affinity of ferrous neuroglobin for nitric oxide. By using ferrous myoglobin as scavenger for nitric oxide, we find that nitric oxide dissociates from ferrous neuroglobin much faster than previously appreciated, consistently with the decay of the Fe(II)–NO product during the reaction. Both neuroglobin and Cytoglobin are S-nitrosated when reacting with nitrite, with neuroglobin showing higher levels of S-nitrosation. The possible biological significance of the reaction between nitrite and neuroglobin in vivo under brain hypoxia is discussed.
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expression purification and crystallization of neuro and Cytoglobin
Methods in Enzymology, 2008Co-Authors: Sylvia Dewilde, Alessandra Pesce, Martino Bolognesi, Laurent Kiger, Michael C Marden, Christophe Lechauve, Kirsten Mees, Luc MoensAbstract:Neuroglobin and Cytoglobin, members of the globin family, are present in vertebrate cells at very low concentrations. As the function of both proteins is still a matter of debate, it is very important to be able to produce and purify these proteins, and in general all members of the globin family, to homogeneity. For this purpose, this chapter describes the expression of neuro- and Cytoglobin by E. coli and its preparative purification. These proteins are then used in crystallization experiments. Also an analytical purification strategy is discussed in detail.
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anoxia or oxygen and glucose deprivation in sh sy5y cells a step closer to the unraveling of neuroglobin and Cytoglobin functions
Gene, 2007Co-Authors: Elke Fordel, Liesbet Thijs, Wim Martinet, Luc Moens, Dorien M Schrijvers, Sylvia DewildeAbstract:Abstract Several studies support the hypothesis that neuroglobin and Cytoglobin play a protective role against cell death when cellular oxygen supply is critical. Although the underlying molecular mechanisms are unknown, previous reports suggest that this protection can be realised by the fact that they act as ROS scavengers. In this study, expression of neuroglobin and Cytoglobin was evaluated in a human neuroblastoma cell line (SH-SY5Y) under conditions of anoxia or oxygen and glucose deprivation (OGD). The cells could survive prolonged anoxia without significant loss of viability. They became anoxia sensitive when deprived of glucose. OGD induced significant cell death after 16 h resulting in 54% dead cells after 32 h. Necrosis was the main process involved in OGD-induced cell death. After reoxygenation, apoptotic neurons became more abundant. Real-time quantitative PCR and Western blotting revealed that neuroglobin and Cytoglobin were upregulated, the former under OGD and the latter under anoxic conditions. Under OGD, cell survival was significantly reduced after inhibiting Cytoglobin expression by transfection with antisense ODN. Moreover, cell survival was significantly enhanced by neuroglobin or Cytoglobin overexpression. When neuroglobin or Cytoglobin protein expression increased or decreased, the H2O2 level was found to be lower or higher, respectively. We conclude that neuroglobin or Cytoglobin act as ROS scavengers under ischemic conditions.
Luc Moens - One of the best experts on this subject based on the ideXlab platform.
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Cytoglobin conformations and disulfide bond formation
FEBS Journal, 2010Co-Authors: Christophe Lechauve, Brian N. Green, Sylvia Dewilde, Michael C Marden, Luc Moens, Cedric Chauvierre, Chantal Celier, Laurent KigerAbstract:The oligomeric state and kinetics of ligand binding were measured for wild-type Cytoglobin. Cytoglobin has the classical globin fold, with an extension at each extremity of about 20 residues. The extended length of Cytoglobin leads to an ambiguous interpretation of its oligomeric state. Although the hydrodynamic diameter corresponds to that of a dimer, it displays a mass of a single subunit, indicating a monomeric form. Thus, rather than displaying a compact globular form, Cytoglobin behaves hydrodynamically like a tightly packed globin with a greater flexibility of the N- and C-terminal regions. Cytoglobin displays biphasic kinetics after the photolysis of CO, as a result of competition with an internal protein ligand, the E7 distal histidine. An internal disulfide bond may form which modifies the rate of dissociation of the distal histidine and apparently leads to different Cytoglobin conformations, which may affect the observed oxygen affinity by an order of magnitude.
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expression purification and crystallization of neuro and Cytoglobin
Methods in Enzymology, 2008Co-Authors: Sylvia Dewilde, Alessandra Pesce, Martino Bolognesi, Laurent Kiger, Michael C Marden, Christophe Lechauve, Kirsten Mees, Luc MoensAbstract:Neuroglobin and Cytoglobin, members of the globin family, are present in vertebrate cells at very low concentrations. As the function of both proteins is still a matter of debate, it is very important to be able to produce and purify these proteins, and in general all members of the globin family, to homogeneity. For this purpose, this chapter describes the expression of neuro- and Cytoglobin by E. coli and its preparative purification. These proteins are then used in crystallization experiments. Also an analytical purification strategy is discussed in detail.
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anoxia or oxygen and glucose deprivation in sh sy5y cells a step closer to the unraveling of neuroglobin and Cytoglobin functions
Gene, 2007Co-Authors: Elke Fordel, Liesbet Thijs, Wim Martinet, Luc Moens, Dorien M Schrijvers, Sylvia DewildeAbstract:Abstract Several studies support the hypothesis that neuroglobin and Cytoglobin play a protective role against cell death when cellular oxygen supply is critical. Although the underlying molecular mechanisms are unknown, previous reports suggest that this protection can be realised by the fact that they act as ROS scavengers. In this study, expression of neuroglobin and Cytoglobin was evaluated in a human neuroblastoma cell line (SH-SY5Y) under conditions of anoxia or oxygen and glucose deprivation (OGD). The cells could survive prolonged anoxia without significant loss of viability. They became anoxia sensitive when deprived of glucose. OGD induced significant cell death after 16 h resulting in 54% dead cells after 32 h. Necrosis was the main process involved in OGD-induced cell death. After reoxygenation, apoptotic neurons became more abundant. Real-time quantitative PCR and Western blotting revealed that neuroglobin and Cytoglobin were upregulated, the former under OGD and the latter under anoxic conditions. Under OGD, cell survival was significantly reduced after inhibiting Cytoglobin expression by transfection with antisense ODN. Moreover, cell survival was significantly enhanced by neuroglobin or Cytoglobin overexpression. When neuroglobin or Cytoglobin protein expression increased or decreased, the H2O2 level was found to be lower or higher, respectively. We conclude that neuroglobin or Cytoglobin act as ROS scavengers under ischemic conditions.
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Neuroglobin and Cytoglobin as potential enzyme or substrate.
Gene, 2007Co-Authors: F Trandafir, P Rivetti Di Val Cervo, K Ramser, Francesca Altieri, Sabine Van Doorslaer, David Hoogewijs, Luc Moens, Jacques R Vanfleteren, Sylvia DewildeAbstract:The possible enzymatic activities of neuro- and Cytoglobin as well as their potential function as substrates in enzymatic reactions were studied. Neuro- and Cytoglobin are found to show no appreciable superoxide dismutase, catalase, and peroxidase activities. However, the internal disulfide bond (CD7-D5) of human neuroglobin can be reduced by thioredoxin reductase. Furthermore, our in vivo and in vitro studies show that Escherichia coli cells contain an enzymatic reducing system that keeps the heme iron atom of neuroglobin in the Fe(2+) form in the presence of dioxygen despite the high autoxidation rate of the molecule. This reducing system needs a low-molecular-weight compound as co-factor. In vitro tests show that both NADH and NADPH can play this role. Furthermore, the reducing system is not specific for neuroglobin but allows the reduction of the ferric forms of other globins such as Cytoglobin and myoglobin. A similar reducing system is present in eukaryotic tissue protein extracts.
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neuroglobin and Cytoglobin expression in mice
FEBS Journal, 2007Co-Authors: Elke Fordel, Liesbet Thijs, Luc Moens, Sylvia DewildeAbstract:Although essentially unknown, several functions are hypothesized for neuroglobin and Cytoglobin, two new members of the globin family. In this article, we try to shed more light on their possible roles in hypoxia and detoxification of reactive oxygen species in vivo. The relative transcriptional changes of neuroglobin and Cytoglobin in a situation of chronic hypoxia in mice were examined using real-time quantitative PCR. The kinetics of the hypoxic expression of neuroglobin (brain, eyes) and Cytoglobin (brain, eyes, liver, heart, skeletal muscle) is organ-specific. Moreover, reactive oxygen species production is higher in liver than in the other tissues. In eyes, the negative correlation, after reoxygenation, between neuroglobin protein level and H2O2 concentration is a first proof of a reactive oxygen species-scavenging function for neuroglobin. In addition, apoptotic cell death after hypoxia is for the first time demonstrated in heart and liver.
Paola Corti - One of the best experts on this subject based on the ideXlab platform.
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abstract 12361 Cytoglobin regulates cilia length function and organ system laterality during development
Circulation, 2019Co-Authors: Elizabeth R Rochon, Mark T Gladwin, Jianmin Xue, Manush Saydmohammed, Michael Tsang, Paola CortiAbstract:Introduction: Cytoglobin is a heme protein known to be expressed at relatively low concentrations in a variety of tissues throughout development and highly conserved in all vertebrates. While cytog...
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the zebrafish cytochrome b5 cytochrome b5 reductase nadh system efficiently reduces Cytoglobins 1 and 2 conserved activity of cytochrome b5 cytochrome b5 reductases during vertebrate evolution
Biochemistry, 2019Co-Authors: Matthew B Amdahl, Courtney Sparacinowatkins, Elin E Petersen, K A Bocian, Stefan Kaliszuk, Anthony W Demartino, Sagarika Tiwari, Jason J Rose, Paola Corti, Mark T GladwinAbstract:: Cytoglobin is a heme protein evolutionarily related to hemoglobin and myoglobin. Cytoglobin is expressed ubiquitously in mammalian tissues; however, its physiological functions are yet unclear. Phylogenetic analyses indicate that the Cytoglobin gene is highly conserved in vertebrate clades, from fish to reptiles, amphibians, birds, and mammals. Most proposed roles for Cytoglobin require the maintenance of a pool of reduced Cytoglobin (FeII). We have shown previously that the human cytochrome b5/cytochrome b5 reductase system, considered a quintessential hemoglobin/myoglobin reductant, can reduce human and zebrafish Cytoglobins ≤250-fold faster than human hemoglobin or myoglobin. It was unclear whether this reduction of zebrafish Cytoglobins by mammalian proteins indicates a conserved pathway through vertebrate evolution. Here, we report the reduction of zebrafish Cytoglobins 1 and 2 by the zebrafish cytochrome b5 reductase and the two zebrafish cytochrome b5 isoforms. In addition, the reducing system also supports reduction of Globin X, a conserved globin in fish and amphibians. Indeed, the zebrafish reducing system can maintain a fully reduced pool for both Cytoglobins, and both cytochrome b5 isoforms can support this process. We determined the P50 for oxygen to be 0.5 Torr for Cytoglobin 1 and 4.4 Torr for Cytoglobin 2 at 25 °C. Thus, even at low oxygen tensions, the reduced Cytoglobins may exist in a predominant oxygen-bound form. Under these conditions, the cytochrome b5/cytochrome b5 reductase system can support a conserved role for Cytoglobins through evolution, providing electrons for redox signaling reactions such as nitric oxide dioxygenation, nitrite reduction, and phospholipid oxidation.
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the zebrafish cytochrome b5 cytochrome b5 reductase nadh system efficiently reduces Cytoglobins 1 and 2 conserved activity of cytochrome b5 cytochrome b5 reductases during vertebrate evolution
Biochemistry, 2019Co-Authors: Matthew B Amdahl, Courtney Sparacinowatkins, Elin E Petersen, Stefan Kaliszuk, Anthony W Demartino, Sagarika Tiwari, Jason J Rose, Paola Corti, Kaitlin Bocian, Mark T GladwinAbstract:Cytoglobin is a heme protein evolutionarily related to hemoglobin and myoglobin. Cytoglobin is expressed ubiquitously in mammalian tissues; however, its physiological functions are yet unclear. Phy...
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nitrite improves zebrafish cardiac regeneration potentially by Cytoglobin 1
Free Radical Biology and Medicine, 2017Co-Authors: Elizabeth R Rochon, Jesus Tejero, Mark T Gladwin, Jianmin Xue, Paola CortiAbstract:Treatment with nitrite (NO2‒) has been shown to have a beneficial effect on ischemia/reperfusion injury via the production of nitric oxide (NO) and modulation of reactive oxygen/nitrogen species (ROS/RNS). Nitrite can be converted to NO through the action of heme globins via a nitrite reductase reaction. The role of NO2‒ and globins has not yet been investigated in the context of heart regeneration. Zebrafish can fully regenerate their hearts following ventricular amputation and were used a model to study the effects of hypoxia and NO2‒ treatment on heart regeneration. We hypothesize that treatment with hypoxia/ NO2‒ will improve cardiac regeneration through increased production of NO or signaling ROS/RNS. We have found that NO2‒ /hypoxia treatment improves the rate of cardiomyocyte proliferation and improves neovascularization compared to hypoxia alone five days post amputation (dpa). Preceding these events, we observe an increase in thrombocytes (1 dpa) and neutrophils (3 dpa) migration to the injured area and a decrease in the blood clot size, suggesting that NO2‒ treatment is able to modulate the immune response to improve healing following injury. Zebrafish Cytoglobin 1 (Cygb1) is a globin that may mediate the cardiac regenerative response to NO2‒. Our data show that Cygb1 is expressed in the epicardium (a tissue that is known to drive the regeneration process) and its expression is increased following cardiac injury. Cygb1 may be mediating this response via its fast nitrite reductase rate (28.6 ± 3.1 M (-1) s(-1)) in its deoxy state or oxy-Cygb1 may react with NO2- to produce RNS, modulating the immune response via ROS/RNS signaling. Given the extremely low Cygb1 oxygen P50 (0.277 torr), we hypothesize that it is the latter, even in the context of the hypoxic heart. Our current research aims to identify the mechanism by which nitrite treatment modulates the immune response in the healing heart and determine if Cygb1 expression is necessary and/or sufficient for cardiac regeneration.
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efficient reduction of vertebrate Cytoglobins by the cytochrome b5 cytochrome b5 reductase nadh system
Biochemistry, 2017Co-Authors: Matthew B Amdahl, Courtney Sparacinowatkins, Paola Corti, Mark T Gladwin, Jesus TejeroAbstract:Cytoglobin is a heme-containing protein ubiquitous in mammalian tissues. Unlike the evolutionarily related proteins hemoglobin and myoglobin, Cytoglobin shows a six-coordinated heme binding, with the heme iron coordinated by two histidine side chains. Cytoglobin is involved in cytoprotection pathways through yet undefined mechanisms, and it has recently been demonstrated that Cytoglobin has redox signaling properties via nitric oxide (NO) and nitrite metabolism. The reduced, ferrous Cytoglobin can bind oxygen and will react with NO in a dioxygenation reaction to form nitrate, which dampens NO signaling. When deoxygenated, Cytoglobin can bind nitrite and reduce it to NO. This oxidoreductase activity could be catalytic if an effective reduction system exists to regenerate the reduced heme species. The nature of the physiological Cytoglobin reducing system is unknown, although it has been proposed that ascorbate and cytochrome b5 could fulfill this role. Here we describe that physiological concentrations of ...
