Browsing by Author "Crans, Debbie C."
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- Biological consequences of Vanadium effects on formation of reactive oxygen species and lipid peroxidationPublication . Aureliano, Manuel; De Sousa-Coelho, Ana Luísa; Dolan, Connor C.; Roess, Deborah A.; Crans, Debbie C.Lipid peroxidation (LPO), a process that affects human health, can be induced by exposure to vanadium salts and compounds. LPO is often exacerbated by oxidation stress, with some forms of vanadium providing protective effects. The LPO reaction involves the oxidation of the alkene bonds, primarily in polyunsaturated fatty acids, in a chain reaction to form radical and reactive oxygen species (ROS). LPO reactions typically affect cellular membranes through direct effects on membrane structure and function as well as impacting other cellular functions due to increases in ROS. Although LPO effects on mitochondrial function have been studied in detail, other cellular components and organelles are affected. Because vanadium salts and complexes can induce ROS formation both directly and indirectly, the study of LPO arising from increased ROS should include investigations of both processes. This is made more challenging by the range of vanadium species that exist under physiological conditions and the diverse effects of these species. Thus, complex vanadium chemistry requires speciation studies of vanadium to evaluate the direct and indirect effects of the various species that are present during vanadium exposure. Undoubtedly, speciation is important in assessing how vanadium exerts effects in biological systems and is likely the underlying cause for some of the beneficial effects reported in cancerous, diabetic, neurodegenerative conditions and other diseased tissues impacted by LPO processes. Speciation of vanadium, together with investigations of ROS and LPO, should be considered in future biological studies evaluating vanadium effects on the formation of ROS and on LPO in cells, tissues, and organisms as discussed in this review.
- Decavavanadate (V10 O6-28) and oxovanadates: oxometalates with many biological activitiesPublication . Aureliano, M.; Crans, Debbie C.The decameric vanadate species V10O6 28 , also referred to as decavanadate, impact proteins, lipid structures and cellular function, and show some effects in vivo on oxidative stress processes and other biological properties. The mode of action of decavanadate in many biochemical systems depends, at least in part, on the charge and size of the species and in some cases competes with the simpler oxovanadate species. The orange decavanadate that contains 10 vanadium atoms is a stable species for several days at neutral pH, but at higher pH immediately converts to the structurally and functionally distinct lower oxovanadates such as the monomer, dimer or tetramer. Although the biological effects of vanadium are generally assumed to derive from monomeric vanadate or the vanadyl cation, we show in this review that not all effects can be attributed to these simple oxovanadate forms. This topic has not previously been reviewed although background information is available [D.C. Crans, Comments Inorg. Chem. 16 (1994) 35–76; M. Aureliano (Ed.), Vanadium Biochemistry, Research Signpost Publs., Kerala, India, 2007]. In addition to pumps, channels and metabotropic receptors, lipid structures represent potential biological targets for decavanadate and some examples have been reported. Decavanadate interact with enzymes, polyphosphate, nucleotide and inositol 3-phosphate binding sites in the substrate domain or in an allosteric site, in a complex manner. In mitochondria, where vanadium was shown to accumulate following decavanadate in vivo administration, nM concentration of decavanadate induces membrane depolarization in addition to inhibiting oxygen consumption, suggesting that mitochondria may be potential targets for decameric toxicity. In vivo effects of decavanadate in piscine models demonstrated that antioxidant stress markers, lipid peroxidation and vanadium subcellular distribution is dependent upon whether or not the solutions administered contain decavanadate. The present review summarizes the reports on biological effects of decavanadate and highlights the importance of considering decavanadate in evaluations of the biological effects of vanadium.
- Effects of decavanadate and insulin enhancing vanadium compounds on glucose uptake in isolated rat adipocytesPublication . Pereira, Maria João; Carvalho, Eugénia; Eriksson, Jan W.; Crans, Debbie C.; Aureliano, M.The effects of different vanadium compounds namely pyridine-2,6-dicarboxylatedioxovanadium(V) (V5-dipic), bis(maltolato) oxovanadium(IV) (BMOV) and amavadine, and oligovanadates namely metavanadate and decavanadate were analysed on basal and insulin stimulated glucose uptake in rat adipocytes. Decavanadate (50 lM), manifest a higher increases (6-fold) on glucose uptake compared with basal, followed by BMOV (1 mM) and metavanadate (1 mM) solutions (3-fold) whereas V5 dipic and amavadine had no effect. Decavanadate (100 lM) also shows the highest insulin like activity when compared with the others compounds studied. In the presence of insulin (10 nM), only decavanadate increases (50%) the glucose uptake when compared with insulin stimulated glucose uptake whereas BMOV and metavanadate, had no effect and V5 dipic and amavadine prevent the stimulation to about half of the basal value. Decavanadate is also able to reduce or eradicate the suppressor effect caused by dexamethasone on glucose uptake at the level of the adipocytes. Altogether, vanadium compounds and oligovanadates with several structures and coordination spheres reveal different effects on glucose uptake in rat primary adipocytes.
- Interaction of decavanadate with interfaces and biological modelmembranesystems:Haracterization of soft oxometale systemsPublication . Aureliano, M.; Samart, Nuttaporn; Saeger, Jessica; Haller, Kenneth J.; Crans, Debbie C.Decavanadate is a polyoxometalate consisting of 10 octahedral vanadium centers, which has been found to exert biological effects and has been observed in vivo. Biological activity implies that a material is taken up into a cell or that the material interacts with membrane receptors. Because of the large size and the high molecular charge, it is nontrivial to anticipate how such a large anion interacts with membranes and whether it will be taken up by cells. Therefore, it becomes important to investigate how the anion interacts with membranes and membrane model systems. Since ion pairing is important for the interaction of this large complex with any membrane interface system, we investigate both the nature of Coulombic and neutral noncovalent interactions with membrane model interface systems and cellular systems. Specifically, we used microemulsions as model systems, and in the specific phase diagram regime where reverse micelles form. We find that, there is a large difference in the interaction with different interfaces, and that charge can have an important role. The negatively charged interface repels the anion, whereas a positive interface attracts the anion. However, the interface with neutral surfactant head groups also is found to repel the decavanadate. This result demonstrates that the discrete charge Coulombic interactions are not the only forces in effect, and that the interactions are at least to a first approximation dictated by the interface charge and not by the counterions in the system. Alternative forces include van der Waals attraction, pH of the water pool, and field and surface effects. Because biological membranes have differently charged ligands, it is not clear which interface systems provide the best analogy with cell surfaces. However, surface charge may affect the compounds and facilitate the interactions that could be important. For example, a positively charged surface could potentially facilitate hydrolysis and sequential abstraction of one or two vanadium atoms at a time from decavanadate. Recently, decavanadate was used as a structural model for the V2O5 material. Negatively charged interfaces have also been found to accelerate compound hydrolysis or in other ways alter reactions in compounds near the interface. Lipid-like interfaces potentially contribute to processing of coordination compounds. Decavanadate has been found to interact with proteins and insulin enhancing effects have been reported. Interactions with coordination compounds and the mechanisms of interactions should continue to be investigated because such systems may reveal the mode of interaction of these compounds.
- Polyoxidovanadates' interactions with proteins: an overviewPublication . Aureliano, Manuel; Gumerova, Nadiia I.; Sciortino, Giuseppe; Garribba, Eugenio; McLauchlan, Craig C.; Rompel, Annette; Crans, Debbie C.Polyoxidovanadates (POVs, previously named polyoxovanadates) are a subgroup of polyoxidometalates (POMs, previously named polyoxometalates) with interesting pharmacological actions that have been tested as potential antidiabetic, antibacterial, antiprotozoal, antiviral, and anticancer drugs. They contain mainly vanadium and are able to interact with proteins, affecting various biological processes. The most studied POV is the isopolyoxidovanadate decavanadate (V-10), which interacts with proteins and/or enzymes such as tyrosine protein phosphatases, P-type ATPases, RNA triphosphatases, myosin and actin. However, in many POVs-protein systems, the binding sites and/or the residues involved in the interaction are not identified. In the present review, the interactions of POVs, as well as linear trivanadate (V-3), both linear and cyclic tetravanadate (V-4) and two proposed heptavanadate (V-7; which are better described by V-10 molecules), with proteins are described through X-ray crystallographic studies. Interactions with POVs through theoretical and spectroscopic studies of proteins related to muscle contraction, serum, oxidative stress, and diabetes were also discussed. In sum, herein, we describe POVs' interactions with various proteins including acid phosphatase A, receptor tyrosine kinase, ectonucleoside triphosphate diphosphohydrolase (NTPDases), transient receptor potential cation channel (TRPM4), phosphoglucomutases, P-type ATPases, myosin, actin, transferrin, albumin, and glucosidases, among others. The putative POVs' effects on proteins are impacted by the POV' stability and speciation. The modes of POVs' interactions include H-bond, electrostatic, H-bond + electrostatic, van der Waals, and covalent binding. The spectroscopic, X-ray and computational results, the sites and modes of binding are described in detail. (C) 2021 The Authors. Published by Elsevier B.V
- Polyoxovanadates with emerging biomedical activitiesPublication . Aureliano, Manuel; Gumerova, Nadiia I.; Sciortino, Giuseppe; Garribba, Eugenio; Rompel, Annette; Crans, Debbie C.Polyoxovanadates (POVs) are a subclass of a larger family of polyanionic group V and VI metal-oxo clus ters that are known as polyoxometalates (POMs). POMs have been found to have antidiabetic, antibacte rial, antiprotozoal, antiviral and anticancer activities, which have sparked interest in their use as bioinorganic drugs. Among POVs, decavanadate ([V10O28] 6 ; V10) is an isopolyoxovanadate recently described to have several medicinal applications. In the present review, recent insights into POVs with emergent anticancer, antimicrobial and antiviral applications are described. Additionally, POVs’ stability and speciation under experimental biological conditions as well as POVs (in particular, V10) in vivo and ex vivo effects are highlighted. Finally, we report the most important 21st century studies of POVs’ effects and/or targets against cancer, bacteria and viruses including: apoptosis, cell cycle arrest, interference with ions transport system, inhibition of mRNA synthesis, cell morphology changes, changes in metabolic pathways, phosphorylase enzyme inhibition and cell signaling, formation of reactive oxygen species, lipid peroxidation, inhibition of viral mRNA polymerase, inhibition of virus binding to the host cell, penetra tion and interaction with virus protein cages.
- Sarcoplasmic reticulum calcium ATPase is inhibited by organic vanadium coordination compounds: pyridine-2-6-dicarboxylatodioxovanadium(V), BMOV and an amavadine analoguePublication . Aureliano, M.; Henao, Fernando; Tiago, Teresa; Duarte, Rui O.; Moura, José J. G.; Baruah, Bharat; Crans, Debbie C.The general affinity of the sarcoplasmic reticulum (SR) Ca2+-ATPase was examined for three different classes of vanadium coordination complexes including a vanadium(V) compound, pyridine-2,6-dicarboxylatodioxovanadium(V) (PDC-V(V)), and two vanadium(IV) compounds, bis(maltolato)oxovanadium(IV) (BMOV), and an analogue of amavadine, bis(N-hydroxylamidoiminodiacetato)vanadium(IV) (HAIDA-V(IV)). The ability of vanadate to act either as a phosphate analogue or as a transition-state analogue with enzymes’ catalysis phosphoryl group transfer suggests that vanadium coordination compounds may reveal mechanistic preferences in these classes of enzymes. Two of these compounds investigated, PDC-V(V) and BMOV, were hydrolytically and oxidatively reactive at neutral pH, and one, HAIDA-V(IV), does not hydrolyze, oxidize, or otherwise decompose to a measurable extent during the enzyme assay. The SR Ca2+-ATPase was inhibited by all three of these complexes. The relative order of inhibition was PDC-V(V) > BMOV > vanadate > HAIDA-V(IV), and the IC50 values were 25, 40, 80, and 325 μM, respectively. Because the observed inhibition is more potent for PDC-V(V) and BMOV than that of oxovanadates, the inhibition cannot be explained by oxovanadate formation during enzyme assays. Furthermore, the hydrolytically and redox stable amavadine analogue HAIDA-V(IV) inhibited the Ca2+-ATPase less than oxovanadates. To gauge the importance of the lipid environment, studies of oxidized BMOV in microemulsions were performed and showed that this system remained in the aqueous pool even though PDC-V(V) is able to penetrate lipid interfaces. These findings suggest that the hydrolytic properties of these complexes may be important in the inhibition of the calcium pump. Our results show that two simple coordination complexes with known insulin enhancing effects can invoke a response in calcium homeostasis and the regulation of muscle contraction through the SR Ca2+-ATPase.