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Kazuo Kobayashi
Bacteria possess molecular biosensors that enable responses to a variety of stressful conditions, including oxidative stress, toxic compounds, and interactions with other organisms, through elaborately coordinated regulation of gene expression. In Escherichia coli and related bacteria, the transcription factor SoxR functions as a sensor of oxidative stress and nitric oxide (NO). SoxR protein contains a [2Fe-2S] cluster essential for its transcription-enhancing activity, which is regulated by redox changes in the [2Fe-2S] cluster...
June 21, 2017: Accounts of Chemical Research
Kirsty Bannister, A H Dickenson
Descending controls, comprising pathways that originate in midbrain and brainstem regions and project onto the spinal cord, have long been recognised as key links in the multiple neural networks that interact to produce the overall pain experience. There is clear evidence from preclinical and clinical studies that both peripheral and central sensitisation play important roles in determining the level of pain perceived. Much emphasis has been put on spinal cord mechanisms in central excitability, but it is now becoming clear that spinal hyperexcitability can be regulated by descending pathways from the brain that originate from predominantly noradrenergic and serotonergic systems...
July 1, 2017: Journal of Physiology
Z Kovacevic, S Sahni, H Lok, M J Davies, D A Wink, D R Richardson
We recently demonstrated that a novel storage and transport mechanism for nitric oxide (NO) mediated by glutathione-S-transferase P1 (GSTP1) and multidrug resistance protein 1 (MRP1/ABCC1), protects M1-macrophage (M1-MØ) models from large quantities of endogenous NO. This system stores and transports NO as dinitrosyl-dithiol-iron complexes (DNICs) composed of iron, NO and glutathione (GSH). Hence, this gas with contrasting anti- and pro-tumor effects, which has been assumed to be freely diffusible, is a tightly-regulated species in M1-MØs...
February 17, 2017: Biochimica et Biophysica Acta
Anatoly F Vanin, Rostislav R Borodulin, Vasak D Mikoyan
Two approaches to the synthesis of dinitrosyl iron complexes (DNIC) with glutathione and l-cysteine in aqueous solutions based on the use of gaseous NO and appropriate S-nitrosothiols, viz., S-nitrosoglutathione (GS-NO) or S-nitrosocysteine (Cys-NO), respectively, are considered. A schematic representation of a vacuum unit for generation and accumulation of gaseous NO purified from the NO2 admixture and its application for obtaining aqueous solutions of DNIC in a Thunberg apparatus is given. To achieve this, a solution of bivalent iron in distilled water is loaded into the upper chamber of the Thunberg apparatus, while the thiol solution in an appropriate buffer (рН 7...
June 1, 2017: Nitric Oxide: Biology and Chemistry
Agnes Keszler, Anne R Diers, Zhen Ding, Neil Hogg
Dinitrosyl iron complexes (DNIC) spontaneously form in aqueous solutions of Fe(II), nitric oxide (NO), and various anions. They exist as an equilibrium between diamagnetic, dimeric (bi-DNIC) and paramagnetic, monomeric (mono-DNIC) forms. Thiolate groups (e.g., on glutathione or protein cysteine residues) are the most biologically relevant anions to coordinate to Fe(II). Low molecular weight DNIC have previously been suggested to be important mediators of NO biology in cells, and emerging literature supports their role in the control of iron-dependent cellular processes...
May 1, 2017: Nitric Oxide: Biology and Chemistry
Randara Pulukkody, Rachel B Chupik, Steven K Montalvo, Sarosh Khan, Nattamai Bhuvanesh, Soon-Mi Lim, Marcetta Y Darensbourg
Both monomeric and dimeric tetraacetylglucose-containing {Fe(NO)2}(9) dinitrosyl iron complexes (DNICs) were prepared and examined for NO release in the presence of both chemical NO-trapping agents and endothelial cells.
January 6, 2017: Chemical Communications: Chem Comm
Chun-Hung Ke, Chien-Hong Chen, Ming-Li Tsai, Hsuan-Chi Wang, Fu-Te Tsai, Yun-Wei Chiang, Wei-Chih Shih, D Scott Bohle, Wen-Feng Liaw
To carry and deliver nitric oxide with a controlled redox state and rate is crucial for its pharmaceutical/medicinal applications. In this study, the capability of cationic {Fe(NO)2}(9) dinitrosyl iron complexes (DNICs) [((R)DDB)Fe(NO)2](+) (R = Me, Et, Iso; (R)DDB = N,N'-bis(2,6-dialkylphenyl)-1,4-diaza-2,3-dimethyl-1,3-butadiene) carrying nearly unperturbed nitric oxide radical to form [((R)DDB)Fe(NO)2((•)NO)](+) was demonstrated and characterized by IR, UV-vis, EPR, NMR, and single-crystal X-ray diffractions...
January 11, 2017: Journal of the American Chemical Society
Vasak D Mikoyan, Evgeniya N Burgova, Rostislav R Borodulin, Anatoly F Vanin
It has been established that treatment of mice with sodium nitrite, S-nitrosoglutathione and the water-soluble nitroglycerine derivative isosorbide dinitrate (ISDN) as NO donors initiates in vivo synthesis of significant amounts of EPR-silent binuclear dinitrosyl iron complexes (B-DNIC) with thiol-containing ligands in the liver and other tissues of experimental mice. This effect is especially apparent if NO donors are administered to mice simultaneously with the Fe(2+)-citrate complex. Similar results were obtained in experiments on isolated liver and other mouse tissues treated with gaseous NО in vitro and during stimulation of endogenous NO synthesis in the presence of inducible NO synthase...
January 30, 2017: Nitric Oxide: Biology and Chemistry
K Bannister, S Lockwood, L Goncalves, R Patel, A H Dickenson
BACKGROUND: Following neuropathy α2-adrenoceptor-mediated diffuse noxious inhibitory controls (DNIC), whereby a noxious conditioning stimulus inhibits the activity of spinal wide dynamic range (WDR) neurons, are abolished, and spinal 5-HT7 receptor densities are increased. Here, we manipulate spinal 5-HT content in spinal nerve ligated (SNL) animals and investigate which 5-HT receptor mediated actions predominate. METHODS: Using in vivo electrophysiology we recorded WDR neuronal responses to von frey filaments applied to the hind paw before, and concurrent to, a noxious ear pinch (the conditioning stimulus) in isoflurane-anaesthetised rats...
April 2017: European Journal of Pain: EJP
Konstantin B Shumaev, Olga V Kosmachevskaya, Elvira I Nasybullina, Sergey V Gromov, Alexander A Novikov, Alexey F Topunov
Dinitrosyl iron complexes (DNICs) are physiological NO derivatives and account for many NO functions in biology. Polyfunctional dipeptide carnosine (beta-alanyl-L-histidine) is considered to be a very promising pharmacological agent. It was shown that in the system containing carnosine, iron ions and Angeli's salt, a new type of DNICs bound with carnosine as ligand {(carnosine)2-Fe-(NO)2}, was formed. We studied how the carbonyl compound methylglyoxal influenced this process. Carnosine-bound DNICs appear to be one of the cell's adaptation mechanisms when the amount of reactive carbonyl compounds increases at hyperglycemia...
January 2017: Journal of Biological Inorganic Chemistry: JBIC
Hiu Chuen Lok, Sumit Sahni, Patric J Jansson, Zaklina Kovacevic, Clare L Hawkins, Des R Richardson
Nitric oxide (NO) is integral to macrophage cytotoxicity against tumors due to its ability to induce iron release from cancer cells. However, the mechanism for how activated macrophages protect themselves from endogenous NO remains unknown. We previously demonstrated by using tumor cells that glutathione S-transferase P1 (GSTP1) sequesters NO as dinitrosyl-dithiol iron complexes (DNICs) and inhibits NO-mediated iron release from cells via the transporter multidrug resistance protein 1 (MRP1/ABCC1). These prior studies also showed that MRP1 and GSTP1 protect tumor cells against NO cytotoxicity, which parallels their roles in defending cancer cells from cytotoxic drugs...
December 30, 2016: Journal of Biological Chemistry
Anne A Fischer, Nuru Stracey, Sergey V Lindeman, Thomas C Brunold, Adam T Fiedler
Mononuclear non-heme iron complexes that serve as structural and functional mimics of the thiol dioxygenases (TDOs), cysteine dioxygenase (CDO) and cysteamine dioxygenase (ADO), have been prepared and characterized with crystallographic, spectroscopic, kinetic, and computational methods. The high-spin Fe(II) complexes feature the facially coordinating tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine ((Ph2)TIP) ligand that replicates the three histidine (3His) triad of the TDO active sites. Further coordination with bidentate l-cysteine ethyl ester (CysOEt) or cysteamine (CysAm) anions yielded five-coordinate (5C) complexes that resemble the substrate-bound forms of CDO and ADO, respectively...
November 21, 2016: Inorganic Chemistry
Shou-Cheng Wu, Chung-Yen Lu, Yi-Lin Chen, Feng-Chun Lo, Ting-Yin Wang, Yu-Jen Chen, Shyng-Shiou Yuan, Wen-Feng Liaw, Yun-Ming Wang
Nitric oxide (NO) is an important cellular signaling molecule that modulates various physiological activities. Angiogenesis-promoting activities of NO-donor drugs have been explored in both experimental and clinical studies. In this study, a structurally well characterized and water-soluble neutral {Fe(NO)2}(9) DNIC [(S(CH2)2OH)(S(CH2)2NH3)Fe(NO)2] (DNIC 2) was synthesized to serve as a NO-donor species. The antitumor activity of DNIC 2 was determined by MTT assay, confocal imaging, and Annexin-V/PI staining...
September 19, 2016: Inorganic Chemistry
Yubin M Kwon, Mayra Delgado, Lev N Zakharov, Takele Seda, John D Gilbertson
The proton-responsive pyridinediimine ligand, (DEA)PDI (where (DEA)PDI = [(2,6-(i)PrC6H3)(N[double bond, length as m-dash]CMe)(N(Et)2C2H4)(N[double bond, length as m-dash]CMe)C5H3N]) was utilized for the reduction of NO2(-) to NO. Nitrite reduction is facilitated by the protonated secondary coordination sphere coupled with the ligand-based redox-active sites of [Fe(H(DEA)PDI)(CO)2](+) and results in the formation of the {Fe(NO)2}(9) DNIC, [Fe((DEA)PDI)(NO)2](+).
September 21, 2016: Chemical Communications: Chem Comm
F Wittkamp, C Nagel, P Lauterjung, B Mallick, U Schatzschneider, U-P Apfel
Here we present the syntheses and structural, spectroscopic, as well as electrochemical properties of four dinitrosyl iron complexes (DNICs) based on silicon- and carbon-derived di- and tripodal phosphines. Whereas CH3C(CH2PPh2)3 and Ph2Si(CH2PPh2)2 coordinate iron in a η(2) - binding mode, CH3Si(CH2PPh2)3 undergoes cleavage of one Si-C bond to afford [Fe(NO)2(P(CH3)Ph2)2] at elevated temperatures. The complexes were characterized by IR spectroelectrochemistry as well as UV-vis measurements. The oxidized {Fe(NO)2}(9) compounds were obtained by oxidation with (NH4)2[Ce(NO3)6] and their properties evaluated with Mössbauer and IR spectroscopy...
June 21, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Amy L Speelman, Bo Zhang, Alexey Silakov, Kelsey M Skodje, E Ercan Alp, Jiyong Zhao, Michael Y Hu, Eunsuk Kim, Carsten Krebs, Nicolai Lehnert
Dinitrosyl iron complexes (DNICs) are among the most abundant NO-derived cellular species. Monomeric DNICs can exist in the {Fe(NO)2}(9) or {Fe(NO)2}(10) oxidation state (in the Enemark-Feltham notation). However, experimental studies of analogous DNICs in both oxidation states are rare, which prevents a thorough understanding of the differences in the electronic structures of these species. Here, the {Fe(NO)2}(9) DNIC [Fe(dmp)(NO)2](OTf) (1; dmp = 2,9-dimethyl-1,10-phenanthroline) is synthesized from a ferrous precursor via an unusual pathway, involving disproportionation of an {FeNO}(7) complex to yield the {Fe(NO)2}(9) DNIC and a ferric species, which is subsequently reduced by NO gas to generate a ferrous complex that re-enters the reaction cycle...
May 20, 2016: Inorganic Chemistry
Yasuo Itomi, Yasuhiro Tsukimi, Toru Kawamura
Fibromyalgia is characterized by chronic widespread musculoskeletal pain. A hypofunction in descending pain inhibitory systems is considered to be involved in the chronic pain of fibromyalgia. We examined functional changes in descending pain inhibitory systems in rats with specific alternation of rhythm in temperature (SART) stress, by measuring the strength of diffuse noxious inhibitory controls (DNIC). Hindpaw withdrawal thresholds to mechanical von Frey filament or fiber-specific electrical stimuli by the Neurometer system were used to measure the pain response...
August 5, 2016: European Journal of Pharmacology
Anatoly F Vanin
The material presented herein is an overview of the results obtained by our research team during the many years' study of biological activities and occurrence of dinitrosyl iron complexes (DNIC) with thiol-containing ligands in human and animal organisms. With regard to their dose dependence and vast diversity of biological activities, DNIC are similar to the system of endogenous NO, one of the most universal regulators of biological processes. The role of biologically active components in DNIC is played by their iron-dinitrosyl fragments, [Fe(NO)2], endowed with the ability to generate neutral NO molecules and nitrosonium ions (NO(+))...
April 1, 2016: Nitric Oxide: Biology and Chemistry
A K Martusevich, A G Soloveval, A V Davydyuk, S P Peretyagin
We have studied the effect of dinitrosyl iron complexes (DNIC) on blood lipid peroxidation and antioxidant system under experimental thermal trauma (burn) conditions in three groups of rats, each containing 10 animals. Group 1 was intact control, groups 2 and 3 were subjected to model thermal trauma, and group 3 were daily intraperitoneally injected with 3 ml of 0.3 mM of aqueous DNIC solution for 10 days. In addition, the DNIC solution action was studied in vitro on isolated human blood with oxidative stress conditions induced by high doses of ozone...
2015: Eksperimental'naia i Klinicheskaia Farmakologiia
Tzung-Wen Chiou, Tsai-Te Lu, Ying-Hao Wu, Yi-Ju Yu, Li-Kang Chu, Wen-Feng Liaw
Despite extensive efforts, the electrocatalytic reduction of water using homogeneous/heterogeneous Fe, Co, Ni, Cu, W, and Mo complexes remains challenging because of issues involving the development of efficient, recyclable, stable, and aqueous-compatible catalysts. In this study, evolution of the de novo designed dinitrosyl iron complex DNIC-PMDTA from a molecular catalyst into a solid-state hydrogen evolution cathode, considering all the parameters to fulfill the electronic and structural requirements of each step of the catalytic cycle, is demonstrated...
December 1, 2015: Angewandte Chemie
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