Regulación de la Respuesta a Hipoxia y la Actividad Mitocondrial por el Óxido Nítrico en las Células Madre Embrionarias y Células de Pluripotencia Inducida

La expansión de las células pluripotentes (ESC e iPS) en condiciones que mantengan sus propiedades de autorenovación y pluripotencia es necesario en un programa de terapia celular. Previamente en nuestro laboratorio hemos observado que bajas concentraciones de óxido nítrico (NO) soportan la expansión de estos tipos celulares (Tejedo JR et al; 2010). Los mecanismos comprometidos en esta respuesta no son conocidos. En este trabajo presentamos evidencias de que cuando estas células crecen en condiciones de normoxia, el NO activa una respuesta similar a la hipoxia, consiguiendo así el mantenimiento de la pluripotencia y la autorrenovación (Catherine E Forristal et al ; 2010).Para comprobar que el NO activa la repuesta celular a hipoxia se ha estudiado la estabilidad y localización celular de la proteína HIFs (factor inductor de hipoxia) mediante western blotting e inmunocitoquímica en las condiciones experimentales de hipoxia, normoxia y normoxia en presencia de bajas concentraciones de NO. También se ha llevado a cabo el estudio de la estabilidad de la proteína von Hippel-Lindau tumor supresor (VHL) encargada de la  degradación de HIF. Por otro lado, dado la estrecha relación existente entre hipoxia y metabolismo celular ( Jin Zhang et al; 2012), hemos analizado la expresión de genes dianas de HIF mediante RT-PCR implicados en la vía glucolítica como son la hexoquinasa-2 (HK-2),  lactato deshidrogensa (LDH) y piruvato deshidrogenasa kinasa1 (PDK1), además del estudio de otros genes diana como, Nanog involucrado en el mantenimiento de la pluripotencia y VEGF cuya función está relacionada con la angiogénesis.Los resultados obtenidos hasta el momento muestran que las células mantenidas en cultivo bajo condiciones de normoxia con bajas concentraciones de DETA-NO (2 y 10 uM) adicionadas al medio para que liberen NO consiguen estabilizar la proteína HIF-1 alpha y tras el análisis de los genes diana de HIF-1 alpha implicados en la vía glucolítca como HK-2, LDH y PDK1 se ha podido comprobar que estos se encuentran sobreexpresados tanto en condiciones de hipoxia como en las condiciones de normoxia más DETA-NO.Tras estos estudios iniciales se puede concluir que bajas concentraciones de NO en condiciones de normoxia consiguen activar una respuesta celular biológica similar a la que ocurre en hipoxia, que se demuestra al observar niveles estables de la proteína que regula esa adaptación celular (HIF) y la sobreexpresión de sus genes diana

Nitric Oxide And Hypoxia Response In Pluripotent Stem Cells

The expansion of pluripotent cells (ESCs and iPSCs) under conditions that maintain their pluripotency is necessary to implement a cell therapy program. Previously, we have described that low nitric oxide (NO) donor diethylenetriamine/nitric oxide adduct (DETA-NO) added to the culture medium, promote the expansion of these cell types. The molecular mechanisms are not yet known. We present evidences that ESC and iPSCs in normoxia in presence of low NO triggers a similar response to hypoxia, thus maintaining the pluripotency. We have studied the stability of HIF-1α (Hypoxia Inducible Factor) in presence of low NO. Because of the close relationship between hypoxia, metabolism, mitochondrial function and pluripotency we have analyzed by q RT-PCR the expression of genes involved in the glucose metabolism such as: HK2, LDHA and PDK1; besides other HIF-1α target gene. We further analyzed the expression of genes involved in mitochondrial biogenesis such as PGC1α, TFAM and NRF1 and we have observed that low NO maintains the same pattern of expression that in hypoxia. The study of the mitochondrial membrane potential using Mito-Tracker dye showed that NO decrease the mitochondrial function. We will analyze other metabolic parameters, to determinate if low NO regulates mitochondrial function and mimics Hypoxia Response. The knowledge of the role of NO in the Hypoxia Response and the mechanism that helps to maintain self-renewal in pluripotent cells in normoxia, can help to the design of culture media where NO could be optimal for stem cell expansion in the performance of future cell therapies

Regulación de la Expresión del Factor de Transcripción Pdx1 por Altas Concentraciones de Óxido Nítrico en Células Madre Embrionarias de Ratón

Estudios previos en nuestro laboratorio muestran que el óxido nítrico a altas concentraciones promueve la diferenciación de células madre embrionarias de ratón (mESC), e induce la expresión de genes de endodermo, entre ellos el factor de transcripción Pdx1, “Pancreas/duodenum homeobox protein 1”. Pdx1, tiene un rol importante en el desarrollo embrionario del páncreas y en la células beta madura. Con el fin de conocer los mecanismos por los que el NO incrementa la expresión de Pdx1, hemos estudiado la región promotora de este gen, encontrando que la expresión de Pdx1 se asocia con la liberación del factor de transcripción Egr1. Además, análisis epigenéticos del promotor muestran que la expresión de Pdx1 va asociada a un cambio en el patrón de metilación de su promotor y a la ocupación de marcas de histonas activadoras (H3Ac y H3K4me3) y a la desocupación de modificadores represores de histonas (HDAC) en el promotor de Pdx1

Low concentrations of nitric oxide delay the differentiation of embryonic stem cells and promote their survival

Nitric oxide (NO) is an intracellular messenger in several cell systems, but its contribution to embryonic stem cell (ESC) biology has not been characterized. Exposure of ESCs to low concentrations (2–20 μM) of the NO donor diethylenetriamine NO adduct confers protection from apoptosis elicited by leukaemia inhibitory factor (LIF) withdrawal. NO blocked caspase 3 activation, PARP degradation, downregulation of the pro-apoptotic genes Casp7, Casp9, Bax and Bak1 and upregulation of the anti-apoptotic genes Bcl-2 111, Bcl-2 and Birc6. These effects were also observed in cells overexpressing eNOS. Exposure of LIF-deprived mESCs to low NO prevented the loss of expression of self-renewal genes (Oct4, Nanog and Sox2) and the SSEA marker. Moreover, NO blocked the differentiation process promoted by the absence of LIF and bFGF in mouse and human ESCs. NO treatment decreased the expression of differentiation markers, such as Brachyury, Gata6 and Gata4. Constitutive overexpression of eNOS in cells exposed to LIF deprivation maintained the expression of self-renewal markers, whereas the differentiation genes were repressed. These effects were reversed by addition of the NOS inhibitor L-NMMA. Altogether, the data suggest that low NO has a role in the regulation of ESC differentiation by delaying the entry into differentiation, arresting the loss of self-renewal markers and promoting cell survival by inhibiting apoptosis

Revista de Vertebrados de la Estación Biológica de Doñana

La reproducción de Hyla meridionalis en el suroeste de EspañaAlimentación y relaciones tróficas entre larvas de Triturus marmoratus, T. alpestris y T. helveticus (Amphibia: CaudataOrganization of behaviour in isolated lizards (Gallotia galloti galloti) as revealed by multivariate analyseComposición y estructura de las comunidades de aves a lo largo de un gradiente altitudinal en tres medios arbustivos del macizo de Ayllón(Sistema Central)La comunidad de aves de un acebuchar del sur de España durante el periodo invernal y de cria.Alimentación del buho chico (Asio otus) en la isla de Tenerife y análisis comparativo con la dieta de Tyto albaAlimentación del zorzal charlo (Turdus viscivoros) en la sierra de Cazorla, SE de España.La migración en España del verderón común (Carduelis chloris, L.) según los resultados de anillamientoIdentificación de los principales quirópteros ibéricos a partir de sus dientes aislados. Valor sistemático de los caracteres morfológicos y métricos dentariosRitmo de actividad en Gazella dorcasSobre la sistemática y biología de Eliomys quercinus en la Cordillera Cantábrica.Primeras citas de Barbus microcephalus Almaça, 1967 (Ostariophysi: Cyprinidae) en EspañaSobre la presencia de Lampetra planeri BLOCH, 1784 en España.Sobre el status taxonómico del género Valencia Myers, 1928 en el suroeste de IberiaNuevas localidades de Chondrostroma polypis Steindachner, 1865 (Ostariophysi, Cyprinidae) en España.Sobre la distribución Gobio gobio (L., 1758)(OSTAOPHYSI, CIPRINIDAE) en EspañaNotas sobre la alimentación de larvas de anfibios: 2. Salamandra salamandra de CazorlaNuevos datos sobre la permanencia de caracteres larvarios en individuos adultos de una población de tritón pirenaico (Euproctus asper) en el valle de AránLa variación del diseño natural como método de reconocimiento individual en Triturus boscaiPresencia de Triturus boscai en la provincia de Córdoba.Datos sobre la alimentación de Athene cunicularia en la Reserva de fauna altoandina de Ulla-Ulla, Bolivia.Falco peregrinus cassini en BoliviaAlgunos datos sobre quirópteros de Galicia.Notas sobre la alimentación de la nutria (Lutra lutra) en el embalse de Matavacas, HuelvaPeer reviewe

Pdx1 is transcriptionally regulated by EGR-1 during nitric oxide-induced endoderm differentiation of mouse embryonic stem cells

The transcription factor, early growth response-1 (EGR-1), is involved in the regulation of cell differentiation, proliferation, and apoptosis in response to different stimuli. EGR-1 is described to be involved in pancreatic endoderm differentiation, but the regulatory mechanisms controlling its action are not fully elucidated. Our previous investigation reported that exposure of mouse embryonic stem cells (mESCs) to the chemical nitric oxide (NO) donor diethylenetriamine nitric oxide adduct (DETA-NO) induces the expression of early differentiation genes such as pancreatic and duodenal homeobox 1 (Pdx1). We have also evidenced that Pdx1 expression is associated with the release of polycomb repressive complex 2 (PRC2) and P300 from the Pdx1 promoter; these events were accompanied by epigenetic changes to histones and site-specific changes in the DNA methylation. Here, we investigate the role of EGR-1 on Pdx1 regulation in mESCs. This study reveals that EGR-1 plays a negative role in Pdx1 expression and shows that the binding capacity of EGR-1 to the Pdx1 promoter depends on the methylation level of its DNA binding site and its acetylation state. These results suggest that targeting EGR-1 at early differentiation stages might be relevant for directing pluripotent cells into Pdx1-dependent cell lineages.C.S.-A. was a doctoral PFIS fellow of ISCIII (FI11/00301). This study was supported by grants from Consejería de Igualdad, Salud y Políticas Sociales, Junta de Andalucía (PI105/2010, TCMR06/009, and PI-0022) to F.J.B. and F.M.; from Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía (CTS-7127/2011) to F.J.B.; from ISCIII cofunded by Fondos FEDER (RED-TERCEL RD 16-011-0034, along with PICI PICI21/00016 and GVA-COVID19/2021/047 to B.S.); from Servicio Andaluz de Salud (SAS 11245), and from Ministerio de Economía y Competitividad- Secretaría de Estado de Investigación Desarrollo e Innovación (IPT-2011-1615-900000). Along with this, there was support to PAIDI group CTS576, and by the European Regional Development Fund (FEDER) and the Consejería de Economía, Conocimiento, Empresas y Universidades de la Junta de Andalucía, within the framework of the operational program FEDER Andalucía 2014–2020. Specific Objective 1.2.3 “Promotion and generation of frontier knowledge and knowledge oriented to the challenges of society, development of emerging technologies” led the reference research project (UPO-1381598) of J.R.T.Peer reviewe

Swimming with Predators and Pesticides: How Environmental Stressors Affect the Thermal Physiology of Tadpoles

To forecast biological responses to changing environments, we need to understand how a species’s physiology varies through space and time and assess how changes in physiological function due to environmental changes may interact with phenotypic changes caused by other types of environmental variation. Amphibian larvae are well known for expressing environmentally induced phenotypes, but relatively little is known about how these responses might interact with changing temperatures and their thermal physiology. To address this question, we studied the thermal physiology of grey treefrog tadpoles (Hyla versicolor) by determining whether exposures to predator cues and an herbicide (Roundup) can alter their critical maximum temperature (CTmax) and their swimming speed across a range of temperatures, which provides estimates of optimal temperature (Topt) for swimming speed and the shape of the thermal performance curve (TPC). We discovered that predator cues induced a 0.4uC higher CTmax value, whereas the herbicide had no effect. Tadpoles exposed to predator cues or the herbicide swam faster than control tadpoles and the increase in burst speed was higher near Topt. In regard to the shape of the TPC, exposure to predator cues increased Topt by 1.5uC, while exposure to the herbicide marginally lowered Topt by 0.4uC. Combining predator cues and the herbicide produced an intermediate Topt that was 0.5uC higher than the control. To our knowledge this is the first study to demonstrate a predator altering the thermal physiology of amphibian larvae (prey) by increasing CTmax, increasing the optimum temperature, and producing changes in the thermal performance curves. Furthermore, these plastic responses of CTmax and TPC to different inducing environments should be considered when forecasting biological responses to global warming.Peer reviewe

Consensus document of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC), the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) and the Spanish Society of Anesthesiology and Resuscitation (SEDAR) on tracheotomy in patients with COVID-19 infection.

La alta incidencia de insuficiencia respiratoria aguda en el contexto de la pandemia por COVID-19ha conllevado el uso de ventilación mecánica hasta en un 15%. Dado que la traqueotomía es un procedimiento quirúrgico frecuente, este documento de consenso, elaborado por tres Sociedades Científicas, la SEMICYUC, la SEDAR y la SEORL-CCC, tiene como objetivo ofrecer una revisión de las indicaciones y contraindicaciones de traqueotomía, ya sea por punción o abierta, esclarecer las posibles ventajas y exponer las condiciones ideales en que deben realizarse y los pasos que considerar en su ejecución. Se abordan situaciones regladas y urgentes, así como los cuidados postoperatorios.post-print393 K

Signalling plasticity and energy saving in a tropical bushcricket

Males of the tropical bushcricket Mecopoda elongata synchronize their acoustic advertisement signals (chirps) in interactions with other males. However, synchrony is not perfect and distinct leader and follower roles are often maintained. In entrainment experiments in which conspecific signals were presented at various rates, chirps displayed as follower showed notable signal plasticity. Follower chirps were shortened by reducing the number and duration of syllables, especially those of low and medium amplitude. The degree of shortening depended on the time delay between leader and follower signals and the sound level of the entraining stimulus. The same signal plasticity was evident in male duets, with the effect that the last syllables of highest amplitude overlapped more strongly. Respiratory measurements showed that solo singing males producing higher chirp rates suffered from higher metabolic costs compared to males singing at lower rates. In contrast, respiratory rate was rather constant during a synchronous entrainment to a conspecific signal repeated at various rates. This allowed males to maintain a steady duty cycle, associated with a constant metabolic rate. Results are discussed with respect to the preference for leader signals in females and the possible benefits males may gain by overlapping their follower signals in a chorus