Regulación de la diferenciación megacariocítica por PTP-Bas y especies reactivas del oxígeno

[ES]El metabolismo aerobio de las células eucariotas comporta la producción de numerosas especies reactivas del oxígeno (ROS), con el consiguiente estrés oxidativo celular. Tradicionalmente este estrés se ha relacionado con efectos dañinos para la célula (Genestra, 2007). Sin embargo, en los últimos años se ha comprobado que los ROS pueden funcionar también como reguladores de la señalización celular. Sin embargo, son muy escasos los artículos que impliquen a los ROS en la regulación de procesos biológicos generales, como por ejemplo la diferenciación celular. En este trabajo, se muestra por primera vez que la diferenciación megacariocítica de las líneas celulares K562 y HEL y de las células humanas CD34+ está acompañada por un rápido incremento de los niveles intracelulares de ROS. Dicho incremento es esencial para que se lleve a cabo el proceso de diferenciación. Mediante experimentos de ARN de interferencia hemos comprobado que la producción de ROS se debe a la actividad de una o varias NADPH oxidasas dependientes de p22phox. La actividad de estas enzimas sería esencial para que se produjera la activación completa de las rutas de señalización más importantes para la diferenciación megacariocítica: la ruta de las MAP quinasas MEK/ERK y la ruta de AKT. Una de las posibles dianas moleculares de los ROS son las proteína tirosina fosfatasas (PTPs). Así, estas enzimas se pueden oxidar por acción de los ROS produciéndose la inhibición de las mismas (Den Hertog, 2005). En nuestro sistema detectamos una disminución de la actividad PTPásica una vez iniciada la diferenciación megacariocítica. Además, el tratamiento con inhibidores de dicha actividad indujo la megacariopoyesis. Cuando analizamos la implicación de PTPs específicas en la diferenciación megacariocítica, comprobamos que la expresión de PTP-Bas se activaba a nivel transcripcional y que la sobreexpresión de dicha enzima ejercía un efecto negativo sobre la megacariopoyesis[EN]Aerobic metabolism of eukaryotic cells involves the production of several reactive oxygen species (ROS), resulting in cellular oxidative stress. Traditionally this stress has been associated with harmful effects on the cell (Genestra, 2007). However, in recent years have shown that ROS can also function as regulators of cell signaling. However, very few articles involving ROS in the regulation of general biological processes such as cell differentiation. In this work, first shown that megakaryocytic differentiation of K562 and HEL cell lines and CD34 + human cells is accompanied by a rapid increase in intracellular ROS levels. This increase is essential to the carrying out the process of differentiation. Using RNA interference experiments have shown that ROS production is due to the activity of one or more NADPH oxidase p22phox-dependent. The activity of these enzymes would be essential for there to be full activation of the signaling pathways leading to megakaryocytic differentiation: the route of the MAP kinase MEK / ERK and AKT path. One possible molecular targets of ROS are protein tyrosine phosphatases (PTPs). Thus, these enzymes can be oxidized by the action of ROS produced inhibition of the same (Den Hertog, 2005). In our system detected a decrease in activity once initiated PTPásica megakaryocytic differentiation. Furthermore, treatment with inhibitors of the activity induced megakaryopoiesis. When we analyzed the involvement of specific PTPs in megakaryocytic differentiation, we found that expression of PTP-Bas was activated at the transcriptional level and that overexpression of this enzyme exerted a negative effect on megakaryopoiesi

Serum Homocysteine Levels in Patients with Retinal Vein Occlusion in a Spanish Population

Purpose Our aim was a) to compare serum Hcy levels in patients with RVO and population-based controls, and b) to evaluate whether hyperhomocysteinemia is a risk factor for RVO. Patients and methods Prospective case-control study of all patients diagnosed with RVO at a tertiary-care hospital, and age-and sex-matched controls taking part in a population-based prospective cohort in the same geographic area. Differences in serum Hcy between both groups were analyzed by a general linear model adjusted for age, body mass index (BMI), glomerular filtration rate (GFR), hypertension, dyslipidemia, diabetes, tobacco use and alcohol intake. Besides, we tested the relationship between hyperhomocysteinemia (> 15 µmol/L) and RVO, by a stepwise logistic regression analysis. Results RVO patients (n = 85) had a higher prevalence of hypertension (p = 0.002), diabetes (p = 0.008), and dyslipidemia (p = 0.04) than controls (n = 82). Adjusted median Hcy levels were higher in RVO patients (p < 0.0001). Adjusted OR for hyperhomocysteinemia were 4.4 (95% CI, 2.0-9.3; p < 0.0001) in the overall sample, and 2.6 (95% CI, 1.04-6.6; p = 0.04) and 6.1 (95% CI, 1.7-21.6; p = 0.005) for men and women, respectively. Conclusion Patients with RVO have higher serum Hcy levels than age- and sex-matched population-based controls. Hyperhomocysteinemia seems to be a risk factor for RVO, independent of age, BMI, GFR and classical vascular risk factors

PTPN13 regulates cellular signalling and ß-catenin function during megakaryocytic differentiation

et al.PTPN13 is a high-molecular weight intracellular phosphatase with several isoforms that exhibits a highly modular structure. Although in recent years different roles have been described for PTPN13, we are still far from understanding its function in cell biology. Here we show that PTPN13 expression is activated during megakaryocytic differentiation at the protein and mRNA level. Our results show that the upregulation of PTPN13 inhibits megakaryocytic differentiation, while PTPN13 silencing triggers differentiation. The ability of PTPN13 to alter megakaryocytic differentiation can be explained by its capacity to regulate ERK and STAT signalling. Interestingly, the silencing of ß-catenin produced the same effect as PTPN13 downregulation. We demonstrate that both proteins coimmunoprecipitate and colocalise. Moreover, we provide evidence showing that PTPN13 can regulate ß-catenin phosphorylation, stability and transcriptional activity. Therefore, the ability of PTPN13 to control megakaryocytic differentiation must be intimately linked to the regulation of ß-catenin function. Moreover, our results show for the first time that PTPN13 is stabilised upon Wnt signalling, which makes PTPN13 an important player in canonical Wnt signalling. Our results show that PTPN13 behaves as an important regulator of megakaryocytic differentiation in cell lines and also in murine haematopoietic progenitors. This importance can be explained by the ability of PTPN13 to regulate cellular signalling, and especially through the regulation of ß-catenin stability and function. Our results hold true for different megakaryocytic cell lines and also for haematopoietic progenitors, suggesting that these two proteins may play a relevant role during in vivo megakaryopoiesis.This work was supported by MCINN (BFU2006-10362, BFU2009-10568, CSD2007-00015, BFU2011-28467 and BFU2011-28804), by JCyL (SA010A10-2, SA126A07 and BIO/SA59/13) and by FEDER-FIS (PS09/01075). G.L.P. and J.L.S. were recipients of a predoctoral fellowship from the Regional Government of Castilla y León-FEDER, Spain.Peer Reviewe

Seasonal abundance of rufous-throated dipper (Cinclus schulzii) in the Southern Yungas of Argentina

Rufous-throated dipper (Cinclus schulzii) is the least known dipper, categorized as ‘Vulnerable’ by IUCN. From the year 2010 to 2013, we surveyed two mountain rivers in the Southern Yungas of Argentina to determine the abundance of this dipper in the breeding and non-breeding season. The overall relative abundance on the breeding season was 1.26 ± 0.07 dippers/km and it did not differ significantly among years. On the non-breeding season, the overall relative abundance was 1.59 ± 0.31 dippers/km and it differed significantly among years. The stable abundance values of the rufous-throated dipper in the breeding season among years could be related to the number of territories that a river can accommodate. The change in the abundance values among years on the non-breeding seasons might be related to the addition of dispersing individuals or of individuals that descend from highlands due to unfavorable conditions at higher elevation. Given the species low abundance values, it is necessary to establish a long-term monitoring scheme.Fil: Sardina Aragon, Patricia Noemi. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentina. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Politi, Natalia. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Rivera, Luis Osvaldo. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Gonzalez, Jose Luis. Universidad Nacional de Jujuy; ArgentinaFil: Barquez, Ruben Marcos. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin

EUS-guided drainage and stent placement for postoperative intra-abdominal and pelvic fluid collections in oncological surgery

Objectives: The objective of this study was to evaluate the role and benefits of endoscopic ultrasonography (EUS) in the management of postoperative intra-abdominal fluid collections after attempted curative surgery for abdominal cancer

The Typology of the Literary Character in E. Adamson’s Prose

Bakalaura darba „Tēlu tipoloģija E.Ādamsona prozā” pamatā ir Erika Ādamsona īsprozas un romāna „Sava ceļa gājējs” tēlu tipoloģijas analīze. Pētītas tēlu raksturīgākās īpatnības, tai skaitā arī kompleksi. Analizētas tās varoņu īpašības, kas nonākot saskarsmē ar dažādiem apstākļiem, maina cilvēka dzīves principus un pat turpmāko likteni, tēlu psiholoģija, personību raksturu veidošanās pamatprincipi. Aplūkoti jautājumi, kuriem bijusi tieša ietekme uz rakstnieka radošo procesu, atsevišķās nodaļās un apakšnodaļās analizēti cilvēku tipi E.Ādamsona novelēs, gadījuma un iedomu akcents cilvēka psihes tēlojumā, kā arī pētīti cilvēku tipi E.Ādamsona romānā „Sava ceļa gājējs”. Vērtēta E.Ādamsona oriģinalitāte prozā un prozas žanriskās piederības problēma. Atslēgas vārdi: Eriks Ādamsons, proza, tēlu tipoloģija, cilvēka psiholoģija, kompleksi.The Bachelor Paper “Typology of Personages in the Prose of E. Ādamsons” is based on the typology analysis of personages of the short prose and the novel “Sava ceļa gājējs” of Eriks Ādamsons. There are studied the most characteristic peculiarities of personages, including their complexes. There are analysed those qualities of the personages, which in different circumstances change the principles of life of a persons and even his/her further fate, psychology of personages, main principles of formation of character of personalities. There are discussed the issues which have had a great impact on the creative process of the author, in separate chapters and subchapters there are analysed the types of persons in the novels of E. Ādamsos, the accent of a chance and illusions in depiction of human psyche, as well as investigated the types of persons in the novel of E. Ādamsons „Sava ceļa gājējs”. There is assessed the originality of E. Ādamsons in prose and the problem of genre belonging of the prose. Key words: Eriks Ādamsons, prose, typology of personages, human psychology, complexes

C/EBPα Activates Pre-existing and De Novo Macrophage Enhancers during Induced Pre-B Cell Transdifferentiation and Myelopoiesis

Summary Transcription-factor-induced somatic cell conversions are highly relevant for both basic and clinical research yet their mechanism is not fully understood and it is unclear whether they reflect normal differentiation processes. Here we show that during pre-B-cell-to-macrophage transdifferentiation, C/EBPα binds to two types of myeloid enhancers in B cells: pre-existing enhancers that are bound by PU.1, providing a platform for incoming C/EBPα; and de novo enhancers that are targeted by C/EBPα, acting as a pioneer factor for subsequent binding by PU.1. The order of factor binding dictates the upregulation kinetics of nearby genes. Pre-existing enhancers are broadly active throughout the hematopoietic lineage tree, including B cells. In contrast, de novo enhancers are silent in most cell types except in myeloid cells where they become activated by C/EBP factors. Our data suggest that C/EBPα recapitulates physiological developmental processes by short-circuiting two macrophage enhancer pathways in pre-B cells

Differential mRNA changes in CBMC progenitor and non-progenitor subpopulations.

<p>(A) Sanger sequencing of <i>WT1</i>-cDNA in subpopulations of cb44 shows that G-to-A alteration at c.1303 is grossly higher in non-progenitor as compared to progenitor subpopulation. G-to-A alteration at both c.1303 (B) and c.1586 (C) were also found to be higher in the non-progenitor subpopulation of cb47 sample, as compared to the progenitor one. (D) Sequencing of the <i>WT1</i>-cDNA clones in cb47 subpopulations confirms the differential changes at c.1303 and c.1586, and also shows a minor T-to-C change at c.1368 which is significantly higher in non-progenitor as compared to the progenitor subpopulation. ** <i>P</i> < 0.01. *** <i>P</i> < 0.001.</p