Ultra-high sensitivity and selectivity of Au nanoparticles modified MoO<inf>3</inf> nanobelts towards 1-butylamine
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15.03.2021 |
Fu H.
Wu Z.
Yang X.
He P.
An X.
Xiong S.
Han D.
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Applied Surface Science |
10.1016/j.apsusc.2020.148721 |
0 |
Ссылка
© 2020 This study demonstrates an ultra-sensitive material towards 1-butylamine. The material is composed of 4 wt% Au nanoparticles decorated on MoO3 nanobelts, which are prepared via the hydrothermal method and in-situ reduction. The related characterizations reveal that the nanobelts are highly crystallized layer structures with a width of ~ 200 nm, a thickness of 40 nm and a length of several micrometers. The Au/MoO3 composites exhibit ultra-high sensing response (~300) towards 100 ppm of 1-butylamine at the working temperature of 240 °C. Even without Au decoration, the pristine MoO3 nanobelts offer the response as high as ~ 90 toward the same concentration of 1-butylamine at the temperature of 340 °C, much higher than the existing materials. More importantly, the proposal materials have excellent selectivity towards 1-butylamine, which offers the possibility for practical use. The excellent sensing performance is attributed to the unique sensing mechanism of the layered MoO3 nanobelts via catalytic reaction between 1-butylamine and the lattice oxygen of MoO3. Besides, Au decoration enables to enhance the adsorption of 1-butylamine and facilitate the catalytic sensing process, resulting in further increase in sensing response and selectivity of 1-butylamine. This study may shield light on a promising high-performance gas sensing materials to detect amines in practical application.
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Resolving the paradox of ferroptotic cell death: Ferrostatin-1 binds to 15LOX/PEBP1 complex, suppresses generation of peroxidized ETE-PE, and protects against ferroptosis
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01.01.2021 |
Anthonymuthu T.S.
Tyurina Y.Y.
Sun W.Y.
Mikulska-Ruminska K.
Shrivastava I.H.
Tyurin V.A.
Cinemre F.B.
Dar H.H.
VanDemark A.P.
Holman T.R.
Sadovsky Y.
Stockwell B.R.
He R.R.
Bahar I.
Bayır H.
Kagan V.E.
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Redox Biology |
10.1016/j.redox.2020.101744 |
0 |
Ссылка
© 2020 The Authors Hydroperoxy-eicosatetraenoyl-phosphatidylethanolamine (HpETE-PE) is a ferroptotic cell death signal. HpETE-PE is produced by the 15-Lipoxygenase (15LOX)/Phosphatidylethanolamine Binding Protein-1 (PEBP1) complex or via an Fe-catalyzed non-enzymatic radical reaction. Ferrostatin-1 (Fer-1), a common ferroptosis inhibitor, is a lipophilic radical scavenger but a poor 15LOX inhibitor arguing against 15LOX having a role in ferroptosis. In the current work, we demonstrate that Fer-1 does not affect 15LOX alone, however, it effectively inhibits HpETE-PE production by the 15LOX/PEBP1 complex. Computational molecular modeling shows that Fer-1 binds to the 15LOX/PEBP1 complex at three sites and could disrupt the catalytically required allosteric motions of the 15LOX/PEBP1 complex. Using nine ferroptosis cell/tissue models, we show that HpETE-PE is produced by the 15LOX/PEBP1 complex and resolve the long-existing Fer-1 anti-ferroptotic paradox.
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Resolving the paradox of ferroptotic cell death: Ferrostatin-1 binds to 15LOX/PEBP1 complex, suppresses generation of peroxidized ETE-PE, and protects against ferroptosis
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01.01.2021 |
Anthonymuthu T.S.
Tyurina Y.Y.
Sun W.Y.
Mikulska-Ruminska K.
Shrivastava I.H.
Tyurin V.A.
Cinemre F.B.
Dar H.H.
VanDemark A.P.
Holman T.R.
Sadovsky Y.
Stockwell B.R.
He R.R.
Bahar I.
Bayır H.
Kagan V.E.
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Redox Biology |
10.1016/j.redox.2020.101744 |
0 |
Ссылка
© 2020 The Authors Hydroperoxy-eicosatetraenoyl-phosphatidylethanolamine (HpETE-PE) is a ferroptotic cell death signal. HpETE-PE is produced by the 15-Lipoxygenase (15LOX)/Phosphatidylethanolamine Binding Protein-1 (PEBP1) complex or via an Fe-catalyzed non-enzymatic radical reaction. Ferrostatin-1 (Fer-1), a common ferroptosis inhibitor, is a lipophilic radical scavenger but a poor 15LOX inhibitor arguing against 15LOX having a role in ferroptosis. In the current work, we demonstrate that Fer-1 does not affect 15LOX alone, however, it effectively inhibits HpETE-PE production by the 15LOX/PEBP1 complex. Computational molecular modeling shows that Fer-1 binds to the 15LOX/PEBP1 complex at three sites and could disrupt the catalytically required allosteric motions of the 15LOX/PEBP1 complex. Using nine ferroptosis cell/tissue models, we show that HpETE-PE is produced by the 15LOX/PEBP1 complex and resolve the long-existing Fer-1 anti-ferroptotic paradox.
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Resolving the paradox of ferroptotic cell death: Ferrostatin-1 binds to 15LOX/PEBP1 complex, suppresses generation of peroxidized ETE-PE, and protects against ferroptosis
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01.01.2021 |
Anthonymuthu T.S.
Tyurina Y.Y.
Sun W.Y.
Mikulska-Ruminska K.
Shrivastava I.H.
Tyurin V.A.
Cinemre F.B.
Dar H.H.
VanDemark A.P.
Holman T.R.
Sadovsky Y.
Stockwell B.R.
He R.R.
Bahar I.
Bayır H.
Kagan V.E.
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Redox Biology |
10.1016/j.redox.2020.101744 |
0 |
Ссылка
© 2020 The Authors Hydroperoxy-eicosatetraenoyl-phosphatidylethanolamine (HpETE-PE) is a ferroptotic cell death signal. HpETE-PE is produced by the 15-Lipoxygenase (15LOX)/Phosphatidylethanolamine Binding Protein-1 (PEBP1) complex or via an Fe-catalyzed non-enzymatic radical reaction. Ferrostatin-1 (Fer-1), a common ferroptosis inhibitor, is a lipophilic radical scavenger but a poor 15LOX inhibitor arguing against 15LOX having a role in ferroptosis. In the current work, we demonstrate that Fer-1 does not affect 15LOX alone, however, it effectively inhibits HpETE-PE production by the 15LOX/PEBP1 complex. Computational molecular modeling shows that Fer-1 binds to the 15LOX/PEBP1 complex at three sites and could disrupt the catalytically required allosteric motions of the 15LOX/PEBP1 complex. Using nine ferroptosis cell/tissue models, we show that HpETE-PE is produced by the 15LOX/PEBP1 complex and resolve the long-existing Fer-1 anti-ferroptotic paradox.
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Elevated energy density and cycle stability of α-Mn<inf>2</inf>O<inf>3</inf> 3D-microspheres with addition of neodymium dopant for pouch-type hybrid supercapacitors
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01.12.2020 |
Karuppaiah M.
Sakthivel P.
Asaithambi S.
Bharat L.K.
Nagaraju G.
Ahamad T.
Balamurugan K.
Yuvakkumar R.
Ravi G.
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Electrochimica Acta |
10.1016/j.electacta.2020.137169 |
0 |
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© 2020 Synthesis of high energy density and long durability electrode materials are huge urgency for futuristic hybrid supercapacitors (HSCs). In the present work, self-assembled three-dimensional (3D)-mesoporous regimented pristine and neodymium (Nd) doped α-Mn2O3 microspheres (MSs) are prepared by simple hydrothermal method. Due to uniform morphology, presence of oxygen vacancies, mesoporous robust structure, and optimum doping (Nd5%-doped Mn2O3 3D-MSs) offers a high specific capacitance of 862.14 F g−1 (431.07 C g−1) at 0.5 A g−1 with superior cycling retention of 97.30% after 2000 cycles. Additionally, a pouch-type HSC device is fabricated using Nd5%-Mn2O3 3D-MSs as a battery-type positive electrode and activated carbon (AC) as a capacitive-type negative electrode. The fabricated device delivers a maximum energy density of 32.26 Wh kg−1 at a power density of 800 W kg−1 with superior cyclic retention and exhibit a little loss of 4.56% after 10,000 cycles. This superior performance is due to robust microstructures that can alleviate swelling and shrinking of active material at cycling test. Two pouch-type HSCs are connected in series to power light-emitting diodes (LEDs) for real-time applicability. Overall, this study demonstrates that rational doping, porous architecture, oxygen vacancies, and robust micro-nano structure greatly assist to achieve high energy density as well as long life HSCs devices.
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Tricalcium phosphate cement supplemented with boron nitride nanotubes with enhanced biological properties
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01.09.2020 |
Rau J.V.
Fosca M.
Fadeeva I.V.
Kalay S.
Culha M.
Raucci M.G.
Fasolino I.
Ambrosio L.
Antoniac I.V.
Uskoković V.
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Materials Science and Engineering C |
10.1016/j.msec.2020.111044 |
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© 2020 Elsevier B.V. A self-setting bone cement containing β-tricalcium phosphate (TCP) supplemented with boron nitride nanotubes (BNNTs, 1 wt%) was synthesized and analyzed in situ for its kinetics of hardening and selected physicochemical and biological properties. Moderately delayed due to the presence of BNNTs, the hardening reaction involved the transformation of the TCP precursor to the dicalcium phosphate (DCPD) product. In spite of the short-lived chemical transformations in the cement upon its hardening, the structural changes in it were extended. As a result, the compressive strength increased from day 1 to day 7 of the hardening reaction and the presence of BNNTs further increased it by ~25%. Fitting of the time-resolved energy-dispersive diffractometric data to the Johnson-Mehl-Avrami-Kolmogorov crystallization kinetics model conformed to the one-dimensional nucleation at a variable rate during the growth of elongated DCPD crystals from round TCP grains. For the first seven days of growth of human mesenchymal stem cells (hMSCs) on the cement, no difference in their proliferation was observed compared to the control. However, between the 7th and the 21st day, the cell proliferation decreased compared to the control because of the ongoing stem cell differentiation toward the osteoblast phenotype. This differentiation was accompanied by the higher expression of alkaline phosphatase, an early marker of hMSC differentiation into a pre-osteoblast phenotype. The TCP cement supplemented with BNNTs was able to thwart the production of reactive oxygen species (ROS) in hMSCs treated with H2O2/Fe2+ and bring the ROS levels down to the concentrations detected in the control cells, indicating the good capability of the material to protect the cells against the ROS-associated damage. Simultaneously, the cement increased the expression of mediators of inflammation in a co-culture of osteoblasts and macrophages, thus attesting to the direct reciprocity between the degrees of inflammation and stimulated new bone production.
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Mitochondrial permeability transition pore is involved in oxidative burst and NETosis of human neutrophils
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01.05.2020 |
Vorobjeva N.
Galkin I.
Pletjushkina O.
Golyshev S.
Zinovkin R.
Prikhodko A.
Pinegin V.
Kondratenko I.
Pinegin B.
Chernyak B.
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Biochimica et Biophysica Acta - Molecular Basis of Disease |
10.1016/j.bbadis.2020.165664 |
0 |
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© 2020 Elsevier B.V. Neutrophils release neutrophil extracellular traps (NETs) in response to numerous pathogenic microbes as the last suicidal resource (NETosis) in the fight against infection. Apart from the host defense function, NETs play an essential role in the pathogenesis of various autoimmune and inflammatory diseases. Therefore, understanding the molecular mechanisms of NETosis is important for regulating aberrant NET release. The initiation of NETosis after the recognition of pathogens by specific receptors is mediated by an increase in intracellular Ca2+ concentration, therefore, the use of Ca2+ ionophore A23187 can be considered a semi-physiological model of NETosis. Induction of NETosis by various stimuli depends on reactive oxygen species (ROS) produced by NADPH oxidase, however, NETosis induced by Ca2+ ionophores was suggested to be mediated by ROS produced in mitochondria (mtROS). Using the mitochondria-targeted antioxidant SkQ1 and specific inhibitors of NADPH oxidase, we showed that both sources of ROS, mitochondria and NADPH oxidase, are involved in NETosis induced by A23187 in human neutrophils. In support of the critical role of mtROS, SkQ1-sensitive NETosis was demonstrated to be induced by A23187 in neutrophils from patients with chronic granulomatous disease (CGD). We assume that Ca2+-triggered mtROS production contributes to NETosis either directly (CGD neutrophils) or by stimulating NADPH oxidase. The opening of the mitochondrial permeability transition pore (mPTP) in neutrophils treated by A23187 was revealed using the electron transmission microscopy as a swelling of the mitochondrial matrix. Using specific inhibitors, we demonstrated that the mPTP is involved in mtROS production, NETosis, and the oxidative burst induced by A23187.
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Lipid peroxidation is involved in calcium dependent upregulation of mitochondrial metabolism in skeletal muscle
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01.03.2020 |
Al-Menhali A.
Banu S.
Angelova P.
Barcaru A.
Horvatovich P.
Abramov A.
Jaganjac M.
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Biochimica et Biophysica Acta - General Subjects |
10.1016/j.bbagen.2019.129487 |
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© 2019 Elsevier B.V. Background: Skeletal muscle cells continuously generate reactive oxygen species (ROS). Excessive ROS can affect lipids resulting in lipid peroxidation (LPO). Here we investigated the effects of myotube intracellular calcium-induced signaling eliciting contractions on the LPO induction and the impact of LPO-product 4-hydroxynonenal (4-HNE) on physiology/pathology of myotubes using C2C12 myoblasts. Methods: C2C12 myoblasts were differentiated into myotubes, stimulated with caffeine and analyzed for the induction of LPO and formation of 4-HNE protein adducts. Further effects of 4-HNE on mitochondrial bioenergetics, NADH level, mitochondrial density and expression of mitochondrial metabolism genes were determined. Results: Short and long-term caffeine stimulation of myotubes promoted superoxide production, LPO and formation of 4-HNE protein adducts. Furthermore, low 4-HNE concentrations had no effect on myotube viability and cellular redox homeostasis, while concentrations from 10 μM and above reduced myotube viability and significantly disrupted homeostasis. A time and dose-dependent 4-HNE effect on superoxide production and mitochondrial NADH-autofluorescence was observed. Finally, 4-HNE had strong impact on maximal respiration, spare respiratory capacity, ATP production, coupling efficiency of mitochondria and mitochondrial density. Conclusion: Data presented in this work make evident for the first time that pathological 4-HNE levels elicit damaging effects on skeletal muscle cells while acute exposure to physiological 4-HNE induces transient adaptation. General significance: This work suggests an important role of 4-HNE on the regulation of myotube's mitochondrial metabolism and cellular energy production. It further signifies the importance of skeletal muscle cells hormesis in response to acute stress in order to maintain essential biological functions.
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Prolonged perfusion of rat brain with a high oxygen tension solution, without oxygen carriers and with an external normal barometric pressure
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01.02.2020 |
Tezikov E.
Pirozhkov S.
Litvitskiy P.
Karateev S.
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Journal of Neuroscience Methods |
10.1016/j.jneumeth.2019.108507 |
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© 2019 Elsevier B.V. Background: Isolated brain of experimental animals is a useful model to study transport of substances, including drugs, across the blood-brain barrier, mechanisms of convulsive activity, ischemic and reperfusion brain injury. Normal functioning of neurons, especially cortical, in the central nervous system requires adequate supply of oxygen. Therefore oxygen carriers or fluorocarbon substances with high oxygen capacity are often used in animal brain perfusion experiments. New method: In the present study of the in situ rat brain perfusion oxygen carriers were not used. The optimum oxygen capacity of the perfusion media (adequate to the arterio-venous difference) was achieved by a high oxygen tension (2400−2600 mm Hg) in the solution under normal barometric pressure. Perfusate was depressurized and delivered at normal rat systemic hydrostatic pressure to the brain via a cannula inserted transcardially into the ascending aorta, with both subclavian arteries ligated. Perfusate was delivered using normal hydrostatic pressure. Results: In these experimental conditions of the brain perfusion the pattern of electrocorticogram has been stable in the course of 5 h and more. The release of lactic acid in the perfusion solution was 3 times less than in perfusion under partial oxygen tension of 900 mm Hg; excessive activation of the lipid peroxidation process in the brain tissue was not observed. Conclusion: The presented new model of the isolated brain perfusion may be used in experiments with other isolated organs and in studies of toxic effects of oxygen.
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A deeper understanding of intestinal organoid metabolism revealed by combining fluorescence lifetime imaging microscopy (FLIM) and extracellular flux analyses
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01.02.2020 |
Okkelman I.
Neto N.
Papkovsky D.
Monaghan M.
Dmitriev R.
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Redox Biology |
10.1016/j.redox.2019.101420 |
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© 2019 Stem cells and the niche in which they reside feature a complex microenvironment with tightly regulated homeostasis, cell-cell interactions and dynamic regulation of metabolism. A significant number of organoid models has been described over the last decade, yet few methodologies can enable single cell level resolution analysis of the stem cell niche metabolic demands, in real-time and without perturbing integrity. Here, we studied the redox metabolism of Lgr5-GFP intestinal organoids by two emerging microscopy approaches based on luminescence lifetime measurement – fluorescence-based FLIM for NAD(P)H, and phosphorescence-based PLIM for real-time oxygenation. We found that exposure of stem (Lgr5-GFP) and differentiated (no GFP) cells to high and low glucose concentrations resulted in measurable shifts in oxygenation and redox status. NAD(P)H-FLIM and O2-PLIM both indicated that at high ‘basal’ glucose conditions, Lgr5-GFP cells had lower activity of oxidative phosphorylation when compared with cells lacking Lgr5. However, when exposed to low (0.5 mM) glucose, stem cells utilized oxidative metabolism more dynamically than non-stem cells. The high heterogeneity of complex 3D architecture and energy production pathways of Lgr5-GFP organoids were also confirmed by the extracellular flux (XF) analysis. Our data reveals that combined analysis of NAD(P)H-FLIM and organoid oxygenation by PLIM represents promising approach for studying stem cell niche metabolism in a live readout.
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Interrogating Parkinson's disease associated redox targets: Potential application of CRISPR editing
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20.11.2019 |
Artyukhova M.
Tyurina Y.
Chu C.
Zharikova T.
Bayır H.
Kagan V.
Timashev P.
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Free Radical Biology and Medicine |
10.1016/j.freeradbiomed.2019.06.007 |
1 |
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© 2019 Elsevier Inc. Loss of dopaminergic neurons in the substantia nigra is one of the pathogenic hallmarks of Parkinson's disease, yet the underlying molecular mechanisms remain enigmatic. While aberrant redox metabolism strongly associated with iron dysregulation and accumulation of dysfunctional mitochondria is considered as one of the major contributors to neurodegeneration and death of dopaminergic cells, the specific anomalies in the molecular machinery and pathways leading to the PD development and progression have not been identified. The high efficiency and relative simplicity of a new genome editing tool, CRISPR/Cas9, make its applications attractive for deciphering molecular changes driving PD-related impairments of redox metabolism and lipid peroxidation in relation to mishandling of iron, aggregation and oligomerization of alpha-synuclein and mitochondrial injury as well as in mechanisms of mitophagy and programs of regulated cell death (apoptosis and ferroptosis). These insights into the mechanisms of PD pathology may be used for the identification of new targets for therapeutic interventions and innovative approaches to genome editing, including CRISPR/Cas9.
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Cationic penetrating antioxidants switch off Mn cluster of photosystem II in situ
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01.11.2019 |
Ptushenko V.
Solovchenko A.
Bychkov A.
Chivkunova O.
Golovin A.
Gorelova O.
Ismagulova T.
Kulik L.
Lobakova E.
Lukyanov A.
Samoilova R.
Scherbakov P.
Selyakh I.
Semenova L.
Vasilieva S.
Baulina O.
Skulachev M.
Kirpichnikov M.
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Photosynthesis Research |
10.1007/s11120-019-00657-2 |
0 |
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© 2019, Springer Nature B.V. Mitochondria-targeted antioxidants (also known as ‘Skulachev Ions’ electrophoretically accumulated by mitochondria) exert anti-ageing and ROS-protecting effects well documented in animal and human cells. However, their effects on chloroplast in photosynthetic cells and corresponding mechanisms are scarcely known. For the first time, we describe a dramatic quenching effect of (10-(6-plastoquinonyl)decyl triphenylphosphonium (SkQ1) on chlorophyll fluorescence, apparently mediated by redox interaction of SkQ1 with Mn cluster in Photosystem II (PSII) of chlorophyte microalga Chlorella vulgaris and disabling the oxygen-evolving complex (OEC). Microalgal cells displayed a vigorous uptake of SkQ1 which internal concentration built up to a very high level. Using optical and EPR spectroscopy, as well as electron donors and in silico molecular simulation techniques, we found that SkQ1 molecule can interact with Mn atoms of the OEC in PSII. This stops water splitting giving rise to potent quencher(s), e.g. oxidized reaction centre of PSII. Other components of the photosynthetic apparatus proved to be mostly intact. This effect of the Skulachev ions might help to develop in vivo models of photosynthetic cells with impaired OEC function but essentially intact otherwise. The observed phenomenon suggests that SkQ1 can be applied to study stress-induced damages to OEC in photosynthetic organisms.
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Role of heme oxygenase as a modulator of heme-mediated pathways
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01.10.2019 |
Duvigneau J.
Esterbauer H.
Kozlov A.
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Antioxidants |
10.3390/antiox8100475 |
0 |
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© 2019 by the authors. Licensee MDPI, Basel, Switzerland. The heme oxygenase (HO) system is essential for heme and iron homeostasis and necessary for adaptation to cell stress. HO degrades heme to biliverdin (BV), carbon monoxide (CO) and ferrous iron. Although mostly beneficial, the HO reaction can also produce deleterious effects, predominantly attributed to excessive product formation. Underrated so far is, however, that HO may exert effects additionally via modulation of the cellular heme levels. Heme, besides being an often-quoted generator of oxidative stress, plays also an important role as a signaling molecule. Heme controls the anti-oxidative defense, circadian rhythms, activity of ion channels, glucose utilization, erythropoiesis, and macrophage function. This broad spectrum of effects depends on its interaction with proteins ranging from transcription factors to enzymes. In degrading heme, HO has the potential to exert effects also via modulation of heme-mediated pathways. In this review, we will discuss the multitude of pathways regulated by heme to enlarge the view on HO and its role in cell physiology. We will further highlight the contribution of HO to pathophysiology, which results from a dysregulated balance between heme and the degradation products formed by HO.
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Insulin Protects Cortical Neurons Against Glutamate Excitotoxicity
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24.09.2019 |
Krasil’nikova I.
Surin A.
Sorokina E.
Fisenko A.
Boyarkin D.
Balyasin M.
Demchenko A.
Pomytkin I.
Pinelis V.
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Frontiers in Neuroscience |
10.3389/fnins.2019.01027 |
0 |
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© Copyright © 2019 Krasil’nikova, Surin, Sorokina, Fisenko, Boyarkin, Balyasin, Demchenko, Pomytkin and Pinelis. Glutamate excitotoxicity is implicated in the pathogenesis of numerous diseases, such as stroke, traumatic brain injury, and Alzheimer’s disease, for which insulin resistance is a concomitant condition, and intranasal insulin treatment is believed to be a promising therapy. Excitotoxicity is initiated primarily by the sustained stimulation of ionotropic glutamate receptors and leads to a rise in intracellular Ca2+ ([Ca2+]i), followed by a cascade of intracellular events, such as delayed calcium deregulation (DCD), mitochondrial depolarization, adenosine triphosphate (ATP) depletion that collectively end in cell death. Therefore, cross-talk between insulin and glutamate signaling in excitotoxicity is of particular interest for research. In the present study, we investigated the effects of short-term insulin exposure on the dynamics of [Ca2+]i and mitochondrial potential in cultured rat cortical neurons during glutamate excitotoxicity. We found that insulin ameliorated the glutamate-evoked rise of [Ca2+]i and prevented the onset of DCD, the postulated point-of-no-return in excitotoxicity. Additionally, insulin significantly improved the glutamate-induced drop in mitochondrial potential, ATP depletion, and depletion of brain-derived neurotrophic factor (BDNF), which is a critical neuroprotector in excitotoxicity. Also, insulin improved oxygen consumption rates, maximal respiration, and spare respiratory capacity in neurons exposed to glutamate, as well as the viability of cells in the MTT assay. In conclusion, the short-term insulin exposure in our experiments was evidently a protective treatment against excitotoxicity, in a sharp contrast to chronic insulin exposure causal to neuronal insulin resistance, the adverse factor in excitotoxicity.
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G-quadruplex-forming oligodeoxyribonucleotides activate leukotriene synthesis in human neutrophils
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22.09.2019 |
Viryasova G.
Dolinnaya N.
Golenkina E.
Gaponova T.
Viryasov M.
Romanova Y.
Sud’ina G.
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Journal of Biomolecular Structure and Dynamics |
10.1080/07391102.2018.1523748 |
2 |
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© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. Human polymorphonuclear leukocytes (PMNLs, neutrophils) play a major role in the immune response to bacterial and fungal infections and eliminate pathogens through phagocytosis. During phagocytosis of microorganisms, the 5-lipoxygenase (5-LOX) pathway is activated resulting in generation of leukotrienes, which mediate host defense. In this study, a library of oligodeoxyribonucleotides (ODNs) with varying numbers of human telomeric repeats (d(TTAGGG)n) and their analogues with phosphorothioate internucleotide linkages and single-nucleotide substitutions was designed. These ODNs with the potential to fold into G-quadruplex structures were studied from structural and functional perspectives. We showed that exogenous G-quadruplex-forming ODNs significantly enhanced 5-LOX metabolite formation in human neutrophils exposed to Salmonella Typhimurium bacteria. However, the activation of leukotriene synthesis was completely lost when G-quadruplex formation was prevented by substitution of guanosine with 7-deazaguanosine or adenosine residues at several positions. To our knowledge, this study is the first to demonstrate that G-quadruplex structures are potent regulators of 5-LOX product synthesis in human neutrophils in the presence of targets of phagocytosis. Communicated by Ramaswamy H. Sarma.
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The subatomic resolution study of laccase inhibition by chloride and fluoride anions using single-crystal serial crystallography: Insights into the enzymatic reaction mechanism
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01.09.2019 |
Polyakov K.
Gavryushov S.
Fedorov T.
Glazunova O.
Popov A.
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Acta Crystallographica Section D: Structural Biology |
10.1107/S2059798319010684 |
0 |
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© 2019 Wiley-Blackwell. All rights reserved. Laccases are enzymes that catalyze the oxidation of a wide range of organic and inorganic substrates accompanied by the reduction of molecular oxygen to water. Here, a subatomic resolution X-ray crystallographic study of the mechanism of inhibition of the laccase from the basidiomycete fungus Steccherinum murashkinskyi by chloride and fluoride ions is presented. Three series of X-ray diffraction data sets were collected with increasing doses of absorbed X-ray radiation from a native S. murashkinskyi laccase crystal and from crystals of complexes of the laccase with chloride and fluoride ions. The data for the native laccase crystal confirmed the previously deduced enzymatic mechanism of molecular oxygen reduction. The structures of the complexes allowed the localization of chloride and fluoride ions in the channel near the T2 copper ion. These ions replace the oxygen ligand of the T2 copper ion in this channel and can play the role of this ligand in the enzymatic reaction. As follows from analysis of the structures from the increasing dose series, the inhibition of laccases by chloride and fluoride anions can be explained by the fact that the binding of these negatively charged ions at the position of the oxygen ligand of the T2 copper ion impedes the reduction of the T2 copper ion.
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An enigmatic catalase of Blastocrithidia
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01.09.2019 |
Bianchi C.
Kostygov A.
Kraeva N.
Záhonová K.
Horáková E.
Sobotka R.
Lukeš J.
Yurchenko V.
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Molecular and Biochemical Parasitology |
10.1016/j.molbiopara.2019.111199 |
0 |
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© 2019 Here we report that trypanosomatid flagellates of the genus Blastocrithidia possess catalase. This enzyme is not phylogenetically related to the previously characterized catalases in other monoxenous trypanosomatids, suggesting that their genes have been acquired independently. Surprisingly, Blastocrithidia catalase is less enzymatically active, compared to its counterpart from Leptomonas pyrrhocoris, posing an intriguing biological question why this gene has been retained in the evolution of trypanosomatids.
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Imaging of oxygen and hypoxia in cell and tissue samples
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01.08.2018 |
Papkovsky D.
Dmitriev R.
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Cellular and Molecular Life Sciences |
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8 |
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© 2018, Springer International Publishing AG, part of Springer Nature. Molecular oxygen (O 2 ) is a key player in cell mitochondrial function, redox balance and oxidative stress, normal tissue function and many common disease states. Various chemical, physical and biological methods have been proposed for measurement, real-time monitoring and imaging of O 2 concentration, state of decreased O 2 (hypoxia) and related parameters in cells and tissue. Here, we review the established and emerging optical microscopy techniques allowing to visualize O 2 levels in cells and tissue samples, mostly under in vitro and ex vivo, but also under in vivo settings. Particular examples include fluorescent hypoxia stains, fluorescent protein reporter systems, phosphorescent probes and nanosensors of different types. These techniques allow high-resolution mapping of O 2 gradients in live or post-mortem tissue, in 2D or 3D, qualitatively or quantitatively. They enable control and monitoring of oxygenation conditions and their correlation with other biomarkers of cell and tissue function. Comparison of these techniques and corresponding imaging setups, their analytical capabilities and typical applications are given.
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Reactive oxygen species and colorectal cancer
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01.07.2018 |
Lin S.
Li Y.
Zamyatnin A.
Werner J.
Bazhin A.
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Journal of Cellular Physiology |
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18 |
Ссылка
© 2017 Wiley Periodicals, Inc. Colorectal cancer (CRC) has become the fourth leading cause of cancer-related death in the worldwide. It is urgent to find more effective therapeutic strategies for it. Reactive oxygen species (ROS) play multiple roles in normal cellular physiology processes. Thus, a certain level of ROS is essential to keep normal cellular function. However, the accumulation of ROS shows dual roles for cells, which is mainly dependent on the concentration of ROS, the origin of the cancer cell and the activated signaling pathways during tumor progression. In general, moderate level of ROS leads to cell damage, DNA mutation and inflammation, which promotes the initiation and development of cancer. Excessive high level of ROS induces cancer cell death, showing an anti-cancer role. ROS are commonly higher in CRC cells than their normal counterpart cells. Therefore, it is possible that ROS induce cell death in cancer cells while not affecting the normal cells, demonstrating lower side effects. Besides, ROS also play a role in tumor microenvironment and drug resistance. These multiple roles of ROS make them a promising therapeutic target for cancer. To explore potential ROS-target therapies against CRC, it is worth to comprehensively understanding the role of ROS in CRC and therapy. In this review, we mainly discuss the strategies of ROS in CRC therapy, including direct CRC cell target and indirect tumor environment target. In addition, the influences of ROS in drug resistance will also been discussed.
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ROS and RNS signalling: adaptive redox switches through oxidative/nitrosative protein modifications
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04.05.2018 |
Moldogazieva N.
Mokhosoev I.
Feldman N.
Lutsenko S.
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Free Radical Research |
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29 |
Ссылка
© 2018 Informa UK Limited, trading as Taylor & Francis Group. Over the last decade, a dual character of cell response to oxidative stress, eustress versus distress, has become increasingly recognized. A growing body of evidence indicates that under physiological conditions, low concentrations of reactive oxygen and nitrogen species (RONS) maintained by the activity of endogenous antioxidant system (AOS) allow reversible oxidative/nitrosative modifications of key redox-sensitive residues in regulatory proteins. The reversibility of redox modifications such as Cys S-sulphenylation/S-glutathionylation/S-nitrosylation/S-persulphidation and disulphide bond formation, or Tyr nitration, which occur through electrophilic attack of RONS to nucleophilic groups in amino acid residues provides redox switches in the activities of signalling proteins. Key requirement for the involvement of the redox modifications in RONS signalling including ROS-MAPK, ROS-PI3K/Akt, and RNS-TNF-α/NF-kB signalling is their specificity provided by a residue microenvironment and reaction kinetics. Glutathione, glutathione peroxidases, peroxiredoxins, thioredoxin, glutathione reductases, and glutaredoxins modulate RONS level and cell signalling, while some of the modulators (glutathione, glutathione peroxidases and peroxiredoxins) are themselves targets for redox modifications. Additionally, gene expression, activities of transcription factors, and epigenetic pathways are also under redox regulation. The present review focuses on RONS sources (NADPH-oxidases, mitochondrial electron-transportation chain (ETC), nitric oxide synthase (NOS), etc.), and their cross-talks, which influence reversible redox modifications of proteins as physiological phenomenon attained by living cells during the evolution to control cell signalling in the oxygen-enriched environment. We discussed recent advances in investigation of mechanisms of protein redox modifications and adaptive redox switches such as MAPK/PI3K/PTEN, Nrf2/Keap1, and NF-κB/IκB, powerful regulators of numerous physiological processes, also implicated in various diseases.
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