Virtual issue by COST Action BM1203 (EU-ROS) “Emerging concepts in redox biology and oxidative stress”

descripción no proporcionada por scopusPeer Reviewe

Current jumps in flat-band ladders with Dzyaloshinskii-Moriya interactions

Localized magnons states, due to flat bands in the spectrum, is an intensely studied phenomenon and can be found in many frustrated magnets of different spatial dimensionality. The presence of Dzyaloshinskii-Moriya (DM) interactions may change radically the behavior in such systems. In this context, we study a paradigmatic example of a one-dimensional frustrated antiferromagnet, the sawtooth chain in the presence of DM interactions. Using both path integrals methods and numerical Density Matrix Renormalization Group, we revisit the physics of localized magnons and determine the consequences of the DM interaction on the ground state. We have studied the spin current behavior, finding three different regimes. First, a Luttinger-liquid regime where the spin current shows a step behavior as a function of parameter D, at a low magnetic field. Increasing the magnetic field, the system is in the Meissner phase at the m = 1/2 plateau, where the spin current is proportional to the DM parameter. Finally, further increasing the magnetic field and for finite D there is a small stiffness regime where the spin current shows, at fixed magnetization, a jump to large values at D = 0, a phenomenon also due to the flat band.Fil: Acevedo, Santiago Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Pujol, P.. Université Paul Sabatier; Francia. Université de Toulouse; FranciaFil: Lamas, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

Protective role for miR-9-5p in the fibrogenic transformation of human dermal fibroblasts

[Background] Excessive accumulation of extracellular matrix (ECM) proteins is the hallmark of fibrotic diseases, including skin fibrosis. This response relies on the activation of dermal fibroblasts that evolve into a pro-fibrogenic phenotype. One of the major players in this process is the cytokine transforming growth factor-β (TGF-β). MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression affecting a wide range of pathophysiological events including fibrogenesis. MicroRNA-9-5p (miR-9-5p) has been shown to exert a protective role in lung and peritoneal fibrosis. This study aimed to evaluate the role of miR-9-5p in skin fibrosis.[Results] miR-9-5p is up-regulated in TGF-β1-treated human dermal fibroblasts (HDFs). In silico identification of miR-9-5p targets spotted the type II TGF-β receptor (TGFBR2) as a potential TGF-β signaling-related effector for this miRNA. Consistently, over-expression of miR-9-5p in HDFs down-regulated TGFBR2 at both the mRNA and protein levels and reduced the phosphorylation of Smad2 and the translocation of Smad2/3 to the nucleus. In keeping, over-expression of miR-9-5p significantly delayed TGF-β1-dependent transformation of dermal fibroblasts, decreasing the expression of ECM protein collagen, type I, alpha 1 (Col1α1), and fibronectin (FN), the amount of secreted collagen proteins, and the expression of the archetypal myofibroblast marker alpha-smooth muscle actin (α-SMA). By contrast, specific inhibition of miR-9-5p resulted in enhanced presence of fibrosis markers. The expression of miR-9-5p was also detected in the skin and plasma in the mouse model of bleomycin-induced dermal fibrosis. Using lentiviral constructs, we demonstrated that miR-9-5p over-expression was also capable of deterring fibrogenesis in this same model.[Conclusions] miR-9-5p significantly prevents fibrogenesis in skin fibrosis. This is mediated by an abrogation of TGF-β-mediated signaling through the down-regulation of TGFBR2 expression in HDFs. These results may pave the way for future diagnostic or therapeutic developments for skin fibrosis based on miR-9-5p.This work was supported by grants from the Ministerio de Economía y Competitividad (MINECO) SAF 2012-31338 and CSD 2007-00020 (SL), Instituto de Salud Carlos III REDinREN RD12/0021/0009, Comunidad de Madrid “Fibroteam” S2010/BMD-2321), and Fundación Renal “Iñigo Alvarez de Toledo,” all from Spain. This study was supported by the European Cooperation in Science and Research COST actions BM-1203 (EU-ROS) and BM-1005 (ENOGAS) (SL). The CBMSO receives institutional support from Fundación “Ramón Areces”. Verónica Miguel is currently supported by the MINECO program of Formación de Personal Investigador (FPI BES-2013-065986). Marta Fierro-Fernández was supported by a postdoctoral grant of the MINECO “Juan de la Cierva” Program. Oscar Busnadiego was a fellow of the FPI program.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)Peer reviewe

L-Plastin S-glutathionylation promotes reduced binding to β-actin and affects neutrophil functions

© 2015 Elsevier Inc. All rights reserved. Posttranslational modifications (PTMs) of cytoskeleton proteins due to oxidative stress associated with several pathological conditions often lead to alterations in cell function. The current study evaluates the effect of nitric oxide (DETA-NO)-induced oxidative stress-related S-glutathionylation of cytoskeleton proteins in human PMNs. By using in vitro and genetic approaches, we showed that S-glutathionylation of L-plastin (LPL) and β-actin promotes reduced chemotaxis, polarization, bactericidal activity, and phagocytosis. We identified Cys-206, Cys-283, and Cys-460 as S-thiolated residues in the β-actin-binding domain of LPL, where cys-460 had the maximum score. Site-directed mutagenesis of LPL Cys-460 further confirmed the role in the redox regulation of LPL. S-Thiolation diminished binding as well as the bundling activity of LPL. The presence of S-thiolated LPL was detected in neutrophils from both diabetic patients and db/db mice with impaired PMN functions. Thus, enhanced nitroxidative stress may results in LPL S-glutathionylation leading to impaired chemotaxis, polarization, and bactericidal activity of human PMNs, providing a mechanistic basis for their impaired functions in diabetes mellitus.Ministerio de Economía y Competitividad (MINECO),SAF 2012–388.Award of research fellowships to M.D.,A.K.S.,D.A.,and S.N. from the Council of Scientific and Industrial Research, India.Peer Reviewe

Adenosine induces mesangial cell contraction by an A1-type receptor

Adenosine induces mesangial cell contraction by an A1-type receptor. Adenosine is known to decrease renal blood flow and glomerular filtration rate. We have tested the hypothesis that adenosine exerts contractile effects on mesangial cells. Furthermore, we have studied, using selective agonists and antagonists for adenosine, which kind of adenosine receptor, A1 or A2, is mainly implicated in this response. We also investigated whether calcium is involved in adenosine-induced mesangial cell contraction. Rat cultured mesangial cells were exposed to adenosine (10−7 to 10−3M) and the contraction was measured as changes in planar cell surface area (PCSA). Adenosine induced a time-and dose-dependent reduction of PCSA. This reduction in PCSA was prevented by incubation with the A1 blocker PD116,948 but not with the A2 blocker PD115,199. Adenosine-5′-ethylcarboxamide (NECA), an A2 agonist, did not induce significant changes in PCSA whereas N6-S-1-methyl-2-phenylethyl adenosine (S-PIA), an A1 agonist, induced a dose-dependent decrease in PCSA Adenosine-induced mesangial contraction was prevented by verapamil or by incubation in a calcium-free medium. These results suggest that adenosine induces a specific contraction of cultured rat mesangial cells that seems to be mediated by its binding to the adenosine A1-type receptor. This contraction seems to be dependent on the influx of extracellular calcium

Regulation of inducible nitric oxide synthase expression in rat mesangial cells and isolated glomeruli

Regulation of inducible nitric oxide synthase expression in rat mesangial cells and isolated glomeruli. The presence of the inducible isoform of nitric oxide synthase (iNOS) in glomerular mesangial cells facilitates the synthesis of nitric oxide (NO) after stimulation with cytokines or lipopolysaccharide (LPS). As the role of NO within the glomerulus may be important in conditions such as glomerulonephritis, we have studied the effect of dexamethasone (DX) and pirrolidine dithiocarbamate (PDTC), an inhibitor of the nuclear transcription factor, NF-κB activation on the induced synthesis of NO in rat mesangial cells (RMC). LPS, tumor necrosis factor-alpha (TNF-α) and the combination of both were able to induce NO synthesis in a dose-dependent manner as measured with the determination of NO2- levels. Treatment with LPS (10 µg/ml) + TNF-α (100 ng/ml) for eight hours was the most potent stimulus for iNOS activity. DX (1 µM) had an inhibitory effect on LPS-, TNF-α- and LPS + TNF-α-induced NO synthesis (51.2, 42.5 and 68% of inhibition, respectively). The inhibitory effect of DX was confirmed using a reporter cell bioassay, whereas cGMP was measured as a reflection of bioactive NO. DX inhibited induced NO synthesis when RMC were exposed to this agent before (16hr of pretreatment, 75.7% inhibition) or at the same time (8hr of cotreatment, 61.2% inhibition) as TNF-α + LPS but not four hours after the stimuli. Northern blot analysis showed marked blunting of mRNA expression in RMC treated with DX, in concordance with functional studies. Both actinomycin D and cycloheximide significantly inhibited NO synthesis and iNOS mRNA expression. PDTC (100 µM) was able to inhibit the iNOS activity induced by LPS and TNF-α independently (56.8 and 49.9% inhibition, respectively), and in combination (79.1% inhibition). PDTC (1 to 100 µM) inhibited LPS + TNF-α-induced NO synthesis and iNOS mRNA expression in a concentration-dependent fashion (69 to 86% inhibition of NO synthesis and 50 to 100% inhibition of mRNA expression). Addition of PDTC four hours after exposure to TNF-α + LPS was still able to markedly inhibit NO synthesis. The effects of DX and PDTC were also demonstrated in isolated glomeruli, where two different combinations of inductive stimuli for NO synthesis were employed. Our results establish DX and PDTC as useful tools to study the regulation of NO synthesis in the mesangial cell and glomerulus, and suggest that NF-κB is involved in the transcriptional regulation of iNOS in RMC

Magnon crystals and magnetic phases in a kagome-stripe antiferromagnet

In this paper we analyze the magnetization properties of an antiferromagnetic kagome-stripe lattice, motivated by the recent synthesis of materials exhibiting this structure. By employing a variety of techniques that include numerical methods such as density-matrix renormalization-group and Monte Carlo simulations, as well as analytical techniques such as perturbative low-energy effective models and exact solutions, we characterize the magnetization process and magnetic phase diagram of a kagome-stripe lattice. The model captures a variety of behaviors present in the two-dimensional kagome lattice, which are described here by analytical models and numerically corroborated. In addition to the characterization of semiclassical intermediate plateaus, it is worth noting the determination of an exact magnon crystal phase which breaks the underlying symmetry of the lattice. This magnon crystal phase generalizes previous findingsFil: Acevedo, Santiago Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Lamas, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Arlego, Marcelo José Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Pujol, Pierre. Universitè de Toulouse; Franci

Recuperação de informações em livros e monografias: algoritmo conceitual e prático para maior revocação

Improvement of subject access to books and monographies, through more exaustive indexing processes, without substantially decreasing information retrieval precision. The applied methodology used titles, subtitles and tables of contents of books and monographies to identify words with a strong capability of conceptual representation for additional subject headings or indexing terms formulation. The research consisted of the analysis of books and monographies included in the bibliographical collection of two different Brazilian Information Systems: a coordinated system and a pre-coordinated one, respectively, the library of the Banco Nacional de Desenvolvimento Econômico e Social -BNDES, and the BIBLIODATA (CALCO) Network. From the titles, subtitles and tables of contents of these documents, words, expressions and proper names were selected for the construction of appropriate subject headings. Hierarchical levels were established to documents' tables of contents, according to their structures. Research results have led to substantial increases in subject access when (compared to subject cataloguing made by the two above-mentioned Information Systems. Results demonstrated the potential of titles, subtitles and tables of contents for identifying words with a high degree of documents' conceptual representation. The results have also demonstrated that the use of words extracted from titles, subtitles and until the second hierarchical level of tables of contents of books and monographies with a less specific approach of subjects, and down to the third hierarchical level of those documents with a more specific approach, the subject headings or indexing terms formulation achieves exaustive and consistent levels, with a great and pertinent conceptual representativeness for future information retrieval. Additionally, the research has pointed out deficiencies in the indexing languages used by both examined Information Systems, [...]CAPESAumento da acessibilidade ao conteúdo informativo de livros e monografias, através de indexações mais exaustivas, sem comprometer os níveis de precisão a ocorrerem na recuperação de informações. A metodologia empregada previu a utilização dos títulos, subtítulos e sumários de livros e monografias a fim de se identificar palavras com elevada capacidade de representação conceitual, destinadas a posterior formação de cabeçalhos de assunto ou termos de indexação. São examinados livros e monografias que igualmente integram os acervos de dois Sistemas de Informação brasileiros: um adepto da pós-coordenação, para os processos de indexação e de recuperação de informações, e outro seguidor da pré-coordenação, respectivamente, a Biblioteca do Banco Nacional de Desenvolvimento Econômico e Social - BNDES e a Rede BIBLIODATA (CALCO). Dos títulos, subtítulos e sumários destes documentos foram selecionados palavras, expressões e nomes próprios para a formação de cabeçalhos pertinentes aos dois Sistemas. Nos sumários dos documentos foram definidos níveis de subordinação, de acordo com sua estrutura hierárquica. Os resultados da pesquisa revelaram substanciais acréscimos em relação a catalogação por assunto efetuada pelos dois Sistemas, como também evidenciaram o potencial do títulos, subtítulos e sumários para a identificação de palavras com elevado grau de representatividade conceitual dos documentos. Os resultados também demonstraram que, recorrendo-se aos títulos, subtítulos e ate ao nível 2 de subordinação dos sumários de livros e monografias com menor especificidade de tratamento dos assuntos, e ate ao nível 3 de subordinação daqueles com maior especificidade, tanto em Sistemas de Informação pós-coordenados quanto em Sistemas pré-coordenados, a formação de cabeçalhos ou de termos de indexação atinge níveis exaustivos e consistentes, com representatividade conceitual pertinente para a posterior recuperação das informações veiculadas pelos documentos..

Numerical and experimental analysis of the velocity field inside an artificial reef. Application to the Ares-Betanzos estuary

[Abstract]: The placement of artificial reef (AR) units on the seabed modifies the velocity field of the water, making the nutrients circulate properly and creating the necessary habitat for the settlement of the desired species. This paper proposes a methodology for determining the circulation in the vicinity of one specific AR unit module previously defined in the existing literature. This has been based on both the application of three-dimensional hydrodynamic criteria and computational fluid dynamics (CFD) together with their validation using towing tank tests. In order to achieve the goals, the starting points are both the initial design of the AR units and the 3D hydrodynamic circulation model in the estuary. The latter predicts the nutrient supply to each module by taking into account the variation of speeds with height. From the vertical profile of circulation velocities, developed for each implantation site, a CFD tool is used to determine the circulation of nutrients in the vicinity of the AR unit, around 5 times the AR size. Then, the results are validated by carrying out towing tank experiments. The main contribution is to combine a circulation model of the estuary together with a CFD model validated with towing tank tests. Although this work was applied to the Ares-Betanzos estuary, it can be extrapolated to other zones worldwide.Xunta de Galicia ; CN-10MMA003C