Contribution of NADPH Oxidase to Membrane CD38 Internalization and Activation in Coronary Arterial Myocytes

The CD38-ADP-ribosylcyclase-mediated Ca2+ signaling pathway importantly contributes to the vasomotor response in different arteries. Although there is evidence indicating that the activation of CD38-ADP-ribosylcyclase is associated with CD38 internalization, the molecular mechanism mediating CD38 internalization and consequent activation in response to a variety of physiological and pathological stimuli remains poorly understood. Recent studies have shown that CD38 may sense redox signals and is thereby activated to produce cellular response and that the NADPH oxidase isoform, NOX1, is a major resource to produce superoxide (O2·−) in coronary arterial myocytes (CAMs) in response to muscarinic receptor agonist, which uses CD38-ADP-ribosylcyclase signaling pathway to exert its action in these CAMs. These findings led us hypothesize that NOX1-derived O2·− serves in an autocrine fashion to enhance CD38 internalization, leading to redox activation of CD38-ADP-ribosylcyclase activity in mouse CAMs. To test this hypothesis, confocal microscopy, flow cytometry and a membrane protein biotinylation assay were used in the present study. We first demonstrated that CD38 internalization induced by endothelin-1 (ET-1) was inhibited by silencing of NOX1 gene, but not NOX4 gene. Correspondingly, NOX1 gene silencing abolished ET-1-induced O2·− production and increased CD38-ADP-ribosylcyclase activity in CAMs, while activation of NOX1 by overexpression of Rac1 or Vav2 or administration of exogenous O2·−significantly increased CD38 internalization in CAMs. Lastly, ET-1 was found to markedly increase membrane raft clustering as shown by increased colocalization of cholera toxin-B with CD38 and NOX1. Taken together, these results provide direct evidence that Rac1-NOX1-dependent O2·− production mediates CD38 internalization in CAMs, which may represent an important mechanism linking receptor activation with CD38 activity in these cells

НОВЫЕ ГИБРИДНЫЕ МАТЕРИАЛЫ ДЛЯ ОРГАНИЧЕСКИХ СВЕТОИЗЛУЧАЮЩИХ ДИОДНЫХ УСТРОЙСТВ

We studied regularities of polymorphous transitions in high−purity powder preparations of metal complex of 8−hydroxyquinoline with aluminum, gallium and indium (Meq3, where Me= Al, Ga, In) in the 300−712 K temperature range. According to the results of luminescent and Raman spectra measurements combined with XRD analysis, the general pattern of the polymorphous transitions in all the investigated compounds is β → α→ δ→ γ → ε. Hybrid materials (HM) were synthesized based on borate glass matrix with 0.02–0.1 wt % Meq3. Bulk samples were obtained by melting, and HM thin films were produced by high vacuum deposition. The luminescent properties of the hybrid materials were studied at room temperature. For the bulk HM an increase in the synthesis duration resulted in the shift of the maximum luminescence peak towards short wavelengths relative to that of pure δ(γ)−Meq3 by 40 nm for Alq3, 15 nm for Gaq3, and 10 nm for Inq3.Изучены закономерности полиморфизма в высокочистых кристаллических три−(8−оксихинолятах) алюминия, галлия и индия (Meq3) в интервале температур от 300 до 712 К. По результатам анализа спектров фотолюминесценции, спектров комбинационного рассеяния света и рентгенофазового анализа построена обобщенная картина, согласно которой последовательность полиморфных переходов для всех изученных соединений одинакова: β → α → δ → γ → ε. На основе высокочистых однофазных препаратов изученных металлокомплексов и оксида бора синтезированы новые гибридные материалы: объемные образцы (методом сплавления), тонкие пленки (вакуумным термическим испарением). Изучены фото− и электролюминесцентные свойства гибридных материалов при комнатной температуре. Установлено, что для объемных гибридных материалов увеличение времени синтеза c 5 до 60 мин приводит к смещению максимума спектра фотолюминесценции от значения, характерного для чистого δ(γ)−Meq3 в коротковолновую область спектра на 40 нм для Alq3, 15 нм для Gaq3 и 10 нм для Inq3

Insights into the Reactivity of Gd_2−xSr_xFe₂O₇ (x = 0 ÷ 0.4) in CO Radical Hydrogenation

The effect of strontium substitution in the structure of the complex oxide Gd2SrFe2O7 on the production of light olefins by CO hydrogenation was investigated. Perovskite-type oxides Gd2−xSr1+xFe2O7 (x = 0; 0.1; 0.2; 0.3; 0.4) were synthesized by sol–gel technology and characterized by XRD, Mössbauer spectroscopy, BET specific area, acidity testing, and SEM. The experimental data revealed a correlation between the state of iron atoms, acidity, and catalytic performance. It was found that with an increase in the content of Sr2+ in the perovskite phase, the basicity of the surface and the oxygen diffusion rate increased. This contributed to the CO dissociative adsorption, formation of active carbon, and its further interaction with atomic hydrogen

Properties of ultra-thin NbN films for membrane-type THz HEB

Various buffer layers have been investigated in order to improve the crystalline quality of NbN ultra-thin films. The structural properties, the thickness, the surface morphology of 5-10 nm NbN films have been studied by different techniques. Uncertainty on thickness measurements in this range and the relation between NbN film quality and gain bandwidth are discussed in the framework of their use in Hot Electron Bolometers (HEB)

Properties of ultra-thin NbN films for membrane-type THz HEB

Various buffer layers have been investigated in order to improve the crystalline quality of NbN ultra-thin films. The structural properties, the thickness, the surface morphology of 5-10 nm NbN films have been studied by different techniques. Uncertainty on thickness measurements in this range and the relation between NbN film quality and gain bandwidth are discussed in the framework of their use in Hot Electron Bolometers (HEB)