Functional role of extracellular matrix proteins and their receptors in apoptosis and cell survival

Macrophages require presence of M-CSF to survive and proliferate. Incubation of bone marrow macrophages with soluble factors (LPS or IFN-gamma) or insoluble factors such as extracellular matrix proteins (Decorin, FN) macrophage proliferation was blocked. Moreover, pretreatment of macrophages with IFN-gamma protects from apoptosis induced by several stimuli. Inhibition of p21Waf with antisense oligonucleotides or using null mice showed that the induction of p21Waf by IFN-gamma mediate this protection. Thus, IFN-gamma makes macrophages unresponsive to apoptotic stimuli by inducing p21Waf and arresting the cell cycle at the G1/S boundary. The insoluble factors, decorin and fibronectin, inhibit macrophage proliferation through p27kip1 expression and the modification of ERK activity. Decorin treated macrophages but not fibronectin protect from apoptosis mechanism that require p21Waf expression. Decorin enhances the IFNgamma-induced expression of IA-alpha and IAß MHC class II genes. Moreover, it increases the IFN-gamma or LPS-induced expression of inducible NO synthase, TNF-alpha, IL-1ß, and IL-6 genes and the secretion of these cytokines. Using a number of extracellular matrix proteins, we found a negative correlation between adhesion and proliferation. However, the effect of decorin on macrophage activation is explained by its ability to block the binding of autocrine-produced TGFß on the surface of macrophages.These soluble and insoluble factors modulate the cell response through the interaction with surface receptors. Cell surface receptors of the integrin family are important regulators of the cell behavior. ß5 cytoplasmic domain has been reported to control cell migration and proliferation. Certain postadhesion are regulated through a pathway that requires both avß5 and PKC activity.Extensive data have been reported on the use of phage libraries to identify ligands. The large molecular diversity represented in phage peptide libraries facilitates the identification of motifs that map to protein interaction sites. Here we introduced an approach based on phage display technology to identify molecules that specifically interact with the cytoplasmic of the ß5 integrin subunit. We showed that a peptide that mimics annexin V binds to the cytoplasmic domain and triggers apoptosis. Annexin V is a cytosolic signaling protein known to inhibit PKC activity, and we demonstrated that annexin-V only binds to active form of PKC. Induction of apoptosis by this peptide is modulated by growth factors and by PKC antagonist. Caspase activity and the expression of ß5 integrin are also required.Caspases play an important role on apoptosis. XIAP functions as a caspase inhibitor and is a member of the inhibitors of apoptosis (IAP) family of proteins. All of the members of the IAP have been shown to inhibit programmed cell death. The human IAP family members bind to caspase 3 and caspase 7 with inhibitory constant values. We have selected peptides from a phage display library by using recombinant full-length human XIAP. A consensus motif was recovered from two independent screenings by using different libraries. Phage displaying variations of the consensus sequence bound specifically to the BIR2 domain of XIAP but not to other IAPs. Protein-protein interaction assays revealed that caspase-3 and -7 blocked the binding of the XIAP-binding phage to XIAP, indicating that this peptide targets a domain within XIAP that is related to the caspase-binding site. We also demonstrated that an internalizing version of the XIAP-binding peptide identified in our screenings could induce apoptosis in leukemia cells.Using a new approach for the screening by phage display technology we also characterize cells surface receptors in endothelial cell activation and proliferation. The molecular diversity in human blood vessels remains largely unexplored. We developed a selection method in which peptides that home to specific vascular beds are identified after administration of a peptide library. These data represents a step toward the construction of a molecular map of human vasculature and may have broad implications for development of targeted therapies

Increased RNA virus population diversity improves adaptability

The replication machinery of most RNA viruses lacks proofreading mechanisms. As a result, RNA virus populations harbor a large amount of genetic diversity that confers them the ability to rapidly adapt to changes in their environment. In this work, we investigate whether further increasing the initial population diversity of a model RNA virus can improve adaptation to a single selection pressure, thermal inactivation. For this, we experimentally increased the diversity of coxsackievirus B3 (CVB3) populations across the capsid region. We then compared the ability of these high diversity CVB3 populations to achieve resistance to thermal inactivation relative to standard CVB3 populations in an experimental evolution setting. We find that viral populations with high diversity are better able to achieve resistance to thermal inactivation at both the temperature employed during experimental evolution as well as at a more extreme temperature. Moreover, we identify mutations in the CVB3 capsid that confer resistance to thermal inactivation, finding significant mutational epistasis. Our results indicate that even naturally diverse RNA virus populations can benefit from experimental augmentation of population diversity for optimal adaptation and support the use of such viral populations in directed evolution efforts that aim to select viruses with desired characteristics.This work was funded by a Grant from the Spanish Ministerio de Ciencia, Innovación y Universidades to RG (BFU2017-86094-R). RG holds the Ramón y Cajal fellowship from the Spanish Ministry of Economy and Competitiveness (RYC-2015-17517) and FM an FPI grant from the Spanish Ministerio de Ciencia, Innovación y Universidades (BES-2016-076677)

Soledad, género e investigación social en la era digital

El uso y consumo de los dispositivos electrónicos y las herramientas digitales han modificado las pautas de comunicación y ocio audiovisual, especialmente entre adolescentes y jóvenes, etapa vital en el que se realiza el paso de la niñez a la edad adulta, también en todo lo relacionado con la masculinidad y la feminidad como construcciones sociales. Por ende, también se han modificado las formas en que abordar su estudio por parte de la investigación social, suponiendo un reto tanto epistemológico como metodológico. A partir de la exposición de algunos de los resultados que arrojaron la tesis doctoral de la autora, ésta reflexiona acerca de de las relaciones sociales, la comunicación y el género en la era digital, una era marcada por la soledad frente a la pantalla.L'ús i el consum dels dispositius electrònics i les eines digitals han modificat les pautes de comunicació i lleure audiovisual, especialment entre adolescents i joves, etapa vital en què es realitza el pas de la infància a l'edat adulta, també en tot allò relacionat amb la masculinitat i la feminitat com a construccions socials. Per tant, també s'han modificat les maneres en què abordar el seu estudi per part de la investigació social, suposant un repte tant epistemològic com metodològic. A partir de l'exposició d'alguns dels resultats que van donar la tesi doctoral de l'autora, aquesta reflexiona sobre les relacions socials, la comunicació i el gènere a l'era digital, una era marcada per la soledat davant de la pantalla.The use and consumption of electronic devices and digital tools have changed the patterns of audiovisual communication and entertainment, especially among adolescents and young people, life stage in which the transition from childhood to adulthood takes place, also in everything related to masculinity and femininity as social constructions. As a result, the ways in which social research approaches their study has chanched too, posing both an epistemological and methodological challenge. Based on the presentation of some of the results of the author's doctoral thesis, she reflects on social relations, communication and gender in the digital era, an era marked by loneliness in front of the screen.O uso e consumo de dispositivos eletrônicos e ferramentas digitais modificaram os padrões de comunicação e entretenimento audiovisual, principalmente entre adolescentes e jovens, etapa vital em que se faz a passagem da infância para a vida adulta, também em tudo relacionado à masculinidade e feminilidade como construções sociais. Assim, as formas como seu estudo é abordado pela pesquisa social também foram modificados, assumindo um desafio tanto epistemológico quanto metodológico. A partir da apresentação de alguns resultados da tese de doutorado da autora, ela reflete sobre relações sociais, comunicação e gênero na era digital, época marcada pela solidão diante da tela

How did i know I was a “trans guy? Documentary analysis of ten famale-to-male youtuber videos

[ES] El aumento de chicas adolescentes declarándose “chicos trans”, que los estudios relacionan con el consumo de redes sociales e Internet, nos obliga a las feministas a indagar en las causas de este fenómeno cultural y su proceso de difusión. Analizamos diez videos de YouTube de diez chicas que se han declarado “chicos trans”, y observamos que su orientación sexual y su rechazo a los roles y estereotipos de la feminidad patriarcal desde la infancia, así como la preferencia por todo aquello socialmente asociado a los niños y chicos, aparecen como indicadores de ser un “chicos trans”. Amplifican así la propuesta de realizar el “cambio de sexo” como forma de abordar el malestar producido por los roles y estereotipos de género.[EN] The increase of adolescent girls declaring themselves to be “trans boys”, which studies relate to the consumption of social networks and the Internet, forces feminists to investigate the causes of this cultural phenomenon and its diffusion process. We analyze ten YouTube videos of ten girls who have declared themselves “trans boys”, and we observe that their sexual orientation and their rejection of the roles and stereotypes of patriarchal femininity since childhood, as well as the preference for everything socially associated with boys, appear as indicators of being a “trans boy”. They thus amplify the proposal of performing a “sex change”as a way to address the discomfort produced by gender roles and stereotype

Género y adolescencia en la era digital: antropología de la socialización audiovisual

Programa Oficial de Doctorado en Sociedad del Conocimiento: Nuevas perspectivas en Documentación, Comunicación y Humanidades. 566V01[Resumo] As recentes innovacións comunicativas digitales deron lugar a novas experiencias adolescentes e xuvenís. Estas adolescencias audiovisuales non son alleas á reprodución dos roles e estereotipos de xénero, que son parte da desigualdade entre homes e mulleres. Podemos observar isto no seu uso diferencial das redes sociais e os distintos dispositivos, ou ben nos seus gustos e preferencias en relación a películas, series ou videoxogos. A súa participación na rede xerou o fenómeno fan que supoñen os e as youtubers, que cos seus videos conseguiron grandes audiencias. Estes novos ídolos reproducen boa parte dos estereotipos de xénero, tanto nos seus contidos como nas estreitas relacións que estableceron co mercado. Como referentes de non ficción, estas estrelas de YouTube pasaron a formar parte dos modelos de masculinidade e feminidade, modelos que tamén ofrecen as grandes industrias culturais a través dos personaxes de ficción, sendo nas parellas sentimentais onde máis notablemente reprodúcense estes estereotipos de xénero. Xa que logo, a desigualdade e o machismo, a miúdo percibidos de forma confusa polos mozos e mozas, segue estando moi presente na socialización dixital actual da adolescencia[Resumen] Las recientes innovaciones comunicativas digitales han dado lugar a nuevas experiencias adolescentes y juveniles. Estas adolescencias audiovisuales no son ajenas a la reproducción de los roles y estereotipos de género, que son parte de la desigualdad entre hombres y mujeres. Podemos observar esto en su uso diferencial de las redes sociales y los distintos dispositivos, o bien en sus gustos y preferencias en relación a películas, series o videojuegos. Su participación en la red ha generado el fenómeno fan que suponen los y las youtubers, que con sus videos han conseguido grandes audiencias. Estos nuevos ídolos reproducen buena parte de los estereotipos de género, tanto en sus contenidos como en las estrechas relaciones que han establecido con el mercado. Como referentes de no ficción, estas estrellas de YouTube han pasado a formar parte de los modelos de masculinidad y feminidad, modelos que también ofrecen las grandes industrias culturales a través de los personajes de ficción, siendo en las parejas sentimentales donde más notablemente se reproducen estos estereotipos de género. Por tanto, la desigualdad y el machismo, a menudo percibidos de forma confusa por los y las jóvenes, sigue estando muy presente en la socialización digital actual de la adolescencia.[Abstract] Recent digital communicative innovations have given place to new adolescent and youth experiences. These audiovisual adolescence are no alien to the reproduction of gender roles and stereotypes, which are part of the inequality between men and women. We can observe this in their differential use of social networks and different devices, or in their likes and preferences in relation to movies, TV series or videogames. Their participation in Internet has generated the fan phenomenon that youtubers suppose, which have achieved large audiences with their videos. These new idols reproduce a big part of gender stereotypes, both in their content and in their close relationships that they have established with the market. As referents of non-fiction, these YouTube stars have become part of the models of masculinity and femininity, models that also offer the big cultural industries through fictional characters, being in the sentimental couples where gender stereotypes are remarkably reproduced. Therefore, inequality and sexism, often confusedly perceived by young people, is still very present in today's digital socialization of adolescenc

Víctimes de la criança selectiva: Els Braquicèfals

Treball presentat a l'assignatura de Deontologia i Veterinària Legal (21223

Behaviour of insulin Langmuir monolayers at the air–water interface under various conditions

Bovine insulin (INS) monolayers were spread from dilute HCl solution on aqueous subphases under various conditions of temperature (1525 °C), pH (110) and salt content (NaCl, Na3PO4, ZnCl2), and plots of surface pressure (π) against mean area per amino acid residue (A) were recorded during their compression at fast and slow barrier speeds. Although the characteristics and behaviour of the monolayers were significantly influenced by these variables, under none of the conditions studied did molecules of the film appear to migrate into the subphase. In most of conditions mentioned above, compression of these films seems likely to cause the partial submersion of the insulin molecules in the subphase, but these structural changes are relatively slow and essentially reversible. The formation of a relatively rigid, compact film structure, by molecular association, seems to be favoured by high subphase pH and by the presence of Zn2+ ions, while low pH and the presence of PO43 ions appear to favour the dissociation of oligomers, the extension of the monomers and the total submersion of their A chains in the subphase during compression. The presence of salts in the subphase also reduces the reversibility of the changes occurred under film compression.Ministerio de Ciencia y Tecnología | Ref. BQU2003-00949Xunta de Galici

A pH-sensitive stearoyl-PEG-poly(methacryloyl sulfadimethoxine)-decorated liposome system for protein delivery: an application for bladder cancer treatment

Stealth pH-responsive liposomes for the delivery of therapeutic proteins to the bladder epithelium were prepared using methoxy-poly(ethylene glycol)5kDa-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (mPEG5kDa-DSPE) and stearoyl-poly(ethylene glycol)-poly(methacryloyl sulfadimethoxine) copolymer (stearoyl-PEG-polySDM), which possesses an apparent pKa of 7.2. Liposomes of 0.2:0.6:100, 0.5:1.5:100 and 1:3:100 mPEG5kDa-DSPE/stearoyl-PEG-polySDM/(soybean phosphatidylcholine + cholesterol) molar ratios were loaded with bovine serum albumin (BSA) as a protein model. The loading capacity was 1.3% w/w BSA/lipid. At pH 7.4, all liposome formulations displayed a negative zeta-potential and were stable for several days. By pH decrease or addition to mouse urine, the zeta potential strongly decreased, and the liposomes underwent a rapid size increase and aggregation. Photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM) analyses showed that the extent of the aggregation depended on the stearoyl-PEG-polySDM/lipid molar ratio. Cytofluorimetric analysis and confocal microscopy showed that at pH 6.5, the incubation of MB49 mouse bladder cancer cells and macrophages with fluorescein isothiocyanate-labelled-BSA (FITC-BSA) loaded and N-(Lissamine Rhodamine B sulfonyl)-1, 2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (rhodamine-DHPE) labelled 1:3:100 mPEG5kDa-DSPE/stearoyl-PEG-polySDM/lipid molar ratio liposomes resulted in a time-dependent liposome association with the cells. At pH 7.4, the association of BSA-loaded liposomes with the MB49 cells and macrophages was remarkably lower than at pH 6.5. Confocal images of bladder sections revealed that 2 h after the instillation, liposomes at pH 7.4 and control non-responsive liposomes at pH 7.4 or 6.5 did not associate nor delivered FITC-BSA to the bladder epithelium. On the contrary, the pH-responsive liposome formulation set at pH 6.5 and soon administered to mice by bladder instillation showed that, 2 h after administration, the pH-responsive liposomes efficiently delivered the loaded FITC-BSA to the bladder epitheliu