Rola miRNA w toksyczności nanocząstek srebra

Toksyczne działanie nanocząstek srebra zostało potwierdzone na wielu liniach komórkowych w tym na linii komórek Hep G2. Na różnice w odpowiedzi komórki na działanie nanocząstek srebra w różnych mediach hodowlanych może składać się wiele czynników, takich jak interferencja mikroRNA (miRNA) oraz stan metaboliczny. Interferencja miRNA jest jednym z procesów epigenetycznych, które służą komórkom prawidłowym do przeprowadzania procesów fizjologicznych niezbędnych do utrzymania zdrowej kondycji tkanki i całego organizmu. Zarówno wzrost jak i spadek odpowiednich miRNA może nieść za sobą konsekwencje w postaci spadku poziomów produktów genów supresorowych lub zwiększenie poziomu białek będących produktem onkogenów. W niniejszej pracy zbadano wpływ nanocząstek srebra na komórki o różnym fenotypie metabolicznym, wpływ nanocząstek srebra na profil miRNA istotnych w powstawaniu i progresji nowotworu oraz wpływ modulacji miRNA na fenotyp komórek poddanych toksycznemu działaniu nanocząstek srebra. Na model badawczy wybrano komórki raka wątrobowokomórkowego linii Hep G2, hodowane w pożywce zawierającej glukozę w stężeniu odzwierciedlającym stężenie prawidłowe u człowieka oraz w pożywce o podwyższonym stężeniu glukozy występującym przy ostrym stanie cukrzycowym. Przeprowadzone w toku rozprawy eksperymenty wykazały, że w zależności od warunków hodowli komórek Hep G2 ich odpowiedź na toksyczne działanie wywołane nanocząstkami srebra jest różna. Stwierdzono, że nanocząstki srebra wywołują zmiany w profilach miRNA w komórkach Hep G2. Transfekcja komórek wykazujących zmieniony profil pod wpływem czynnika badanego, syntetycznymi analogami miRNA nawet w niewielkich stężeniach, może cofać zmiany wywołane tym czynnikiem.Diamentowy Grant Ministerstwa Nauki i Szkolnictwa Wyższego o numerze DI2016009546; Dofinansowanie na działalność polegającą na prowadzeniu badań naukowych lub prac rozwojowych oraz zadań z nimi związanych, służących rozwojowi młodych naukowców oraz uczestników studiów doktoranckich finansowanych w wewnętrznym trybie konkursowym Uniwersytetu Łódzkiego na rok 201

Products of Lipid Peroxidation as a Factor in the Toxic Effect of Silver Nanoparticles

In our previous study we have shown that nanoparticles have different effects depending on the energy metabolism of the cell, which is an important factor in the context of oncology and diabetes. Here we assess the influence of AgNPs on cellular lipid components in varying glucose concentrations. To assess the effect of silver nanoparticles on cell lipids, we measured cell viability, the fluidity of the cell membranes, the content of amino groups in proteins, the level of lipid peroxidation products, the concentration of 4-hydroxynonenal (4-HNE), and the concentration of lipid peroxides. The obtained results show differences in the formation of lipid peroxidation products in cells exposed to oxidative stress induced by nanoparticles. In addition, we have shown that the metabolic state of the cell is a factor significantly affecting this process

A simple and safe method for the preparation of bis[2-(2H-tetrazol-5-yl)pyridinium] tetrachloridozincate(II)

In the title complex salt, (C6H6N5)2[ZnCl4], the ZnII cation is coordinated by four chloride ligands in a distorted tetrahedral geometry. The organic cations and complex anions are connected by N-H...Cl hydrogen bonds, leading to the formation of a three-dimensional network. The title complex salt was synthesized by the reaction of sodium azide, pyridine-2-carbonitrile and ZnCl2 in aqueous solution. The salt was characterized by elemental analysis and IR and UV-Vis spectroscopy

How to Use Respiratory Chain Inhibitors in Toxicology Studies—Whole-Cell Measurements

Mitochondrial electron transport chain (ETC) inhibition is a phenomenon interesting in itself and serves as a tool for studying various cellular processes. Despite the fact that searching the term “rotenone” in PubMed returns more than 6900 results, there are many discrepancies regarding the directions of changes reported to be caused by this RTC inhibitor in the delicate redox balance of the cell. Here, we performed a multifaceted study of the popular ETC inhibitors rotenone and antimycin A, involving assessment of mitochondrial membrane potential and the production of hydrogen peroxide and superoxide anions at cellular and mitochondrial levels over a wide range of inhibitor concentrations (1 nmol/dm3–100 µmol/dm3). All measurements were performed with whole cells, with accompanying control of ATP levels. Antimycin A was more potent in hindering HepG2 cells’ abilities to produce ATP, decreasing ATP levels even at a 1 nmol/dm3 concentration, while in the case of rotenone, a 10,000-times greater concentration was needed to produce a statistically significant decrease. The amount of hydrogen peroxide produced in the course of antimycin A biological activity increased rapidly at low concentrations and decreased below control level at a high concentration of 100 µmol/dm3. While both inhibitors influenced cellular superoxide anion production in a comparable manner, rotenone caused a greater increase in mitochondrial superoxide anions compared to a modest impact for antimycin A. IC50 values for rotenone and antimycin A with respect to HepG2 cell survival were of the same order of magnitude, but the survival curve of cells treated with rotenone was clearly biphasic, suggesting a concentration-dependent mode of biological action. We propose a clear experimental setup allowing for complete and credible analysis of the redox state of cells under stress conditions which allows for better understanding of the effects of ETC inhibition

Silver nanoparticles can attenuate nitrative stress

We have reported previously that glucose availability can modify toxicity of silver nanoparticles (AgNPs) via elevation of antioxidant defence triggered by increased mitochondrial generation of reactive oxygen species. In this study, we examined the effect of glucose availability on the production of reactive nitrogen species in HepG2 cells and modification of nitrative stress by AgNPs. We found that lowering the glucose concentration increased expression of genes coding for inducible nitric oxide syntheas, NOS2 and NOS2A resulting in enhanced production of nitric oxide. Surprisingly, AgNPs decreased the level of nitric oxide accelerated denitration of proteins nitrated by exogenous peroxynitrite in cells grown in the presence of lowered glucose concentration, apparently due to further induction of protective proteins. Keywords: Silver nanoparticles, Reactive nitrogen species, Reactive oxygen specie

Mo(IV) and W(IV) cyanido complexes with schiff bases : synthesis, X-ray single crystal structures, physicochemical properties and quantum chemical calculations

In the reaction of salicylaldehyde derivatives and aminoethanol with Mo(IV) or W(IV) cyanido complexes, six new salts were isolated and characterized by physicochemical measurements. The single crystal X-ray analysis of four salts of the formula (PPh 4 ) 2 [M(CN) 3 O(LL)] n H 2 O, (where LL = Schiff bases formed in situ in the reaction of aminoethanol and 5-bromo-, 5-chloro-, 5-methoxy-, 3,5-dichloro- or 5-bromo- 3-methoxy-substituted salicylaldehyde, M = Mo or W, n = 1, 1.5, 2 or 5 water molecules) reveals a dis- torted octahedral geometry of the anions. All the complexes were characterized by elemental analysis, IR and UV–Vis spectroscopy and by cyclic voltammetry measurements. The role of the salicylaldehyde substituents on the structures and physicochemical properties is discussed. The results are compared with quantum chemical calculations, indicating that, contrary to literature data, even strong hydrogen bonds do not influence the anion structure

Synthesis, crystal structures and spectroscopy studies of Mo(IV) complexes synthesized in reactions with kojic acid, maltol and ethylmaltol

In the reaction of maltol and its derivatives with a Mo(IV) cyano complex, three new salts were isolated and characterized by physicochemical measurements. The X-ray single crystal measurements of two salts of the formula (PPh 4 ) 2 [Mo(CN) 3 O(LL)] 3H 2 O, where LL = maltol or ethylmaltol, show a distorted octahe- dral geometry of the anions. The steric hindrance introduced by the ethyl group changes mainly the inter- molecular distances in the solid state and the network of hydrogen bonds. All the synthesized salts were compared and discussed with the family of NO, NN and OO donating [Mo(CN) 3 O(LL)] n groups. The role of the ligand protonation constant on the isolation of the products is presented by the synthesis of a (PPh 4 ) 2 [Mo(CN) 4 O(H 2 O)] 5H 2 O salt

Synthesis, structural characterization and spectroscopy studies of new oxovanadium(IV, V) complexes with hydrazone ligands

The reaction of vanadyl acetoacetonate, VO(acac) 2 , with 2-hydroxybenzaldehyde hydrazone in ethanol gave the mononuclear oxovanadium(IV) complex [VO(salh 1 ) 2 ]( 1 ). However, when the hydrazides 3-hydroxy-2-naphthoic acid hydrazide (h 2 ) and 5-phenylisoxazole-3-carboxylicacidhydrazide (h 3 ) were used, the mononuclear oxoethoxovanadium(V) complexes [VO(acanh 2 )(OEt)] ( 2 ) and [VO(acanh 3 )(OEt)] ( 3 ) were isolated, respectively. The reaction with benzene-1,4-dicarbohydrazide (h 4 ) in a water–ethanol solution gave polynuclear {[VO( l -EtO) 2 ]( l -acanh 4 )} n ( 4 ). The complexes were characterized by elemental analysis, IR, UV–Vis and 51 V NMR spectra. Magnetic susceptibility measurements indicated the +5 vanadium oxidation state in 2 , 3 and 4 and +4 in 1 . X-ray single crystal diffraction studies revealed that the vanadium(V) center has a distorted square pyramidal geometry in 2 and 3 , and a distorted octahedral geometry in 4 , with an O 3 N coordination environment around the V(V) acceptor center. Complex 4 is a polymeric compound with dihydrazide ligand as a linker and each two vanadium ions are connected via two l -ethoxo bridges