Effect of the β-amyloid peptide on microglia activation: ATP release

Previous studies have shown a key role of microglial cells in the neuroinflammatory processes associated with some neurodegenerative diseases, such as Alzheimer’s disease (AD). Microglia sense several types of diffusible molecules that regulate the multiple repertoire of microglial functions. Among them, extracellular nucleotides, acting on microglial P2 receptors, have central roles. In this sense, the ionotropic P2X7 receptor has gained recognition as a key regulator of microglial-mediated inflammatory responses.It is known that microglia releases ATP and other nucleotides to the extracellular medium. Although several mechanisms, such as release trough conexins or panexins, has been proposed, a vesicular origin for this released nucleotides, relying on the activity of the vesicular nucleotide transporter (VNUT), cannot be ruled out.In this work we evaluated whether the expression of VNUT and the P2X7 receptor, as well as the ATP release, could be modified in the reactive microglia. To achieve microglia activation we stimulated the cells with the lipopolysaccharide (LPS). Moreover, we analyzed the effect of the b-amyloid peptide b1-42, which is also able to activate the microglial cells, on the expression of VNUT and the ATP release in the microglia.Previous studies have shown a key role of microglial cells in the neuroinflammatory processes associated with some neurodegenerative diseases, such as Alzheimer’s disease (AD). Microglia sense several types of diffusible molecules that regulate the multiple repertoire of microglial functions. Among them, extracellular nucleotides, acting on microglial P2 receptors, have central roles. In this sense, the ionotropic P2X7 receptor has gained recognition as a key regulator of microglial-mediated inflammatory responses.It is known that microglia releases ATP and other nucleotides to the extracellular medium. Although several mechanisms, such as release trough conexins or panexins, has been proposed, a vesicular origin for this released nucleotides, relying on the activity of the vesicular nucleotide transporter (VNUT), cannot be ruled out.In this work we evaluated whether the expression of VNUT and the P2X7 receptor, as well as the ATP release, could be modified in the reactive microglia. To achieve microglia activation we stimulated the cells with the lipopolysaccharide (LPS). Moreover, we analyzed the effect of the b-amyloid peptide b1-42, which is also able to activate the microglial cells, on the expression of VNUT and the ATP release in the microgli

El transportador vesicular de nucleótidos (VNUT). Relevancia en tejidos neurales y neuroendocrinos. Nuevas perspectivas farmacológicas

Vesicular storage of neurotransmitters, which allows their subsequent exocytotic release, is essential for chemical transmission in neurons and endocrine cells. Neurotransmitter uptake to secretory vesicles is carried out by vesicular transporters, which use the electrochemical gradient of protons generated by a vacuolar proton-ATPase as transport driving force. ATP and other nucleotides and dinucleotides are relevant signaling molecules that participate in a variety of biological process. Although the active transport of nucleotides has been pharmacologically and biochemically characterized in a diversity of secretory vesicles, the protein responsible for such vesicular accumulation remained unidentified for some time. In 2008, SLC17A9, the last identified member of the SLC17 transporter family, was found to encode the vesicular nucleotide transporter (VNUT). VNUT is expressed in various ATP-secreting cells and is able to transport several nucleotides in a vesicular membrane potential- dependent fashion. VNUT knockout mice lack vesicular storage and release of ATP from neurons and neuroendocrine cells, resulting in blockage of the purinergic chemical transmission. This review summarizes the current studies on VNUT and analyzes the relevance of vesicular nucleotide transport in different cells types and tissues. The possible use of VNUT inhibitors and interference RNA to reduce VNUT gene expression for therapeutic purposes is also discussed.El almacenamiento vesicular de los neurotransmisores, que permite su subsecuente liberación exocitótica, es un proceso esencial para la transmisión química en neuronas y células endocrinas. La acumulación de los neurotransmisores en vesículas de secreción se lleva a cabo por medio de transportadores vesiculares, que utilizan el gradiente electroquímico de protones generado por una ATPasa vacuolar como fuerza impulsora del transporte. El ATP, así como otros nucleótidos y dinucleótidos, son importantes moléculas señalizadoras que intervienen en una gran variedad de procesos biológicos. Aunque el transporte activo de nucleótidos se ha caracterizado desde el punto de vista bioquímico y farmacológico en una variedad de vesículas de secreción, la proteína responsable de esta acumulación vesicular permaneció durante mucho tiempo desconocida. En 2008, se demostró que SLC17A9, el último miembro identificado de la familia de transportadores SLC17, codifica el transportador vesicular de nucleótidos (VNUT). VNUT se expresa en una variedad de células que liberan ATP y ha mostrado ser capaz de transportar varios nucleótidos de manera dependiente del potencial de membrana vesicular. Ratones deficientes en VNUT pierden la capacidad de almacenar y liberar ATP de neuronas y células neuroendocrinas, lo que resulta en un bloqueo de la transmisión química purinérgica. En esta revisión se pretende resumir los estudios llevados a cabo hasta la fecha sobre VNUT y analizar la relevancia del transporte vesicular de nucleótidos en distintos tipos celulares y tejidos. Asimismo, se discute el posible uso de inhibidores de VNUT, así como de ARNs de interferencia que reduzcan su expresión, con fines terapéuticos

Nucleotides-Induced Changes in the Mechanical Properties of Living Endothelial Cells and Astrocytes, Analyzed by Atomic Force Microscopy

Endothelial cells and astrocytes preferentially express metabotropic P2Y nucleotide receptors, which are involved in the maintenance of vascular and neural function. Among these, P2Y1 and P2Y2 receptors appear as main actors, since their stimulation induces intracellular calcium mobilization and activates signaling cascades linked to cytoskeletal reorganization. In the present work, we have analyzed, by means of atomic force microscopy (AFM) in force spectroscopy mode, the mechanical response of human umbilical vein endothelial cells (HUVEC) and astrocytes upon 2MeSADP and UTP stimulation. This approach allows for simultaneous measurement of variations in factors such as Young’s modulus, maximum adhesion force and rupture event formation, which reflect the potential changes in both the stiffness and adhesiveness of the plasma membrane. The largest effect was observed in both endothelial cells and astrocytes after P2Y2 receptor stimulation with UTP. Such exposure to UTP doubled the Young’s modulus and reduced both the adhesion force and the number of rupture events. In astrocytes, 2MeSADP stimulation also had a remarkable effect on AFM parameters. Additional studies performed with the selective P2Y1 and P2Y13 receptor antagonists revealed that the 2MeSADP-induced mechanical changes were mediated by the P2Y13 receptor, although they were negatively modulated by P2Y1 receptor stimulation. Hence, our results demonstrate that AFM can be a very useful tool to evaluate functional native nucleotide receptors in living cells

Programa de formación complementaria para doctorandos: Aplicación de las nuevas tecnologías y redes sociales (FOCODO)

Este proyecto de innovación docente va dirigido específicamente a los alumnos de doctorado de las Facultades de Óptica y optometría y de Veterinaria de la Universidad Complutense. Pero también es Desarrollar un programa de formación complementaria para los doctorandos en ciencias de la salud que les permita adquirir conocimiento y habilidades en áreas paralelas al ámbito en el que están realizando sus tesis doctorales. El programa de formación tendrá 4 areas temáticas diferenciadas: - Habilidades de comunicación (como escribir un artículo científico, como hacer presentaciones orales y en poster, como escribir un Proyecto científico, como trabajar en equipo, …) - Conocimiento complementario a la tesis doctoral (estadística, metodología científica, lectura crítica de bibliografía, Buenas prácticas de laboratorio, buenas prácticas clínicas, …) - Salidas profesionales durante y después de la tesis doctoral (Becas pre y postdoctorales, búsqueda de proyectos de investigación, como colaborar con otros grupos de investigación,…) - Formación especifica en su área temática (técnicas de laboratorio, técnicas clínicas, revisiones bibliográficas,…) Se generará material de tres tipos: - Seminarios.- Son presentaciones de una hora de duración sobre temas específicos a los que se puede asistir en directo o poder ver grabado a través de YouTube. Estos seminarios serán impartidos por profesores e investigadores de los grupos de investigacion que hacen la propuesta además de contar con especialistas nacionales e internacionales - Pildoras.- Videos cortos de no mas de 3 minutos que resuman los aspectos mas importantes de cada seminario que serán colgados en las pagina de los grupos de investigacion que se creen en las redes sociales. Estas píldoras serán grabadas utilizando herramientas de grabación habituales para videos en redes sociales (croma, focos, …) - Summer/Winter School.- Curos de verano y/o invierno donde en dos-tres días intensivos se imparta formacion especifica en investigacion. En estos cursos participaran profesores y expertos internacionales y estará abierto para la matriculación de estudiantes no complutenses, tanto nacionales como internacionales. Para llevar a cabo este programa se utilizarán varias herramientas: - Plataformas digitales (YouTube) donde se colgarán los seminarios que se realicen. - Redes sociales (Instagram, Twitter,…) donde se colgarán las píldoras que se realicen y además se harán reuniones en directo para debatir temas de alguna de las áreas propuestas anteriormente. - App para móvil desde donde los alumnos puedan encontrar todo el material que se genere durante el programa. Este app puede ser gratuita para los alumnos complutenses y de pago para el resto.Depto. de Optometría y VisiónFac. de Óptica y OptometríaFALSEsubmitte

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

International lower limb collaborative (INTELLECT) study: a multicentre, international retrospective audit of lower extremity open fractures

Trauma remains a major cause of mortality and disability across the world1, with a higher burden in developing nations2. Open lower extremity injuries are devastating events from a physical3, mental health4, and socioeconomic5 standpoint. The potential sequelae, including risk of chronic infection and amputation, can lead to delayed recovery and major disability6. This international study aimed to describe global disparities, timely intervention, guideline-directed care, and economic aspects of open lower limb injuries