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International audience; Gliadins are major wheat allergens. Their treatment by acid or enzymatic hydrolysis has been shown to modify their allergenic potential. As the interaction of food proteins with dendritic cells (DCs) is a key event in allergic sensitization, we wished to investigate whether deamidation and enzymatic hydrolysis influence gliadin processing by DC and to examine the capacity of gliadins to activate DCs. We compared the uptake and degradation of native and modified gliadins by DCs using mouse bone marrow-derived DCs. We also analyzed the effects of these interactions on the phenotypes of DCs and T helper (Th) lymphocytes. Modifying gliadins induced a change in physicochemical properties (molecular weight, hydrophobicity, and sequence) and also in the peptide size. These alterations in turn led to increased uptake and intracellular degradation of the proteins by DCs. Native gliadins (NGs) (100 μg/mL), but not modified gliadins, increased the frequency of DC expressing CD80 (15.41 ± 2.36% vs 6.81 ± 1.10%, p < 0.001), CCR7 (28.53 ± 8.17% vs 17.88 ± 2.53%, p < 0.001), CXCR4 (70.14 ± 4.63% vs 42.82 ± 1.96%, p < 0.001), and CCR7-dependent migration (2.46 ± 1.45 vs 1.00 ± 0.22, p < 0.01) compared with NGs. This was accompanied by Th lymphocyte activation (30.37 ± 3.87% vs 21.53 ± 3.14%, p < 0.1) and proliferation (16.39 ± 3.97% vs 9.31 ± 2.80%, p > 0.1). Moreover, hydrolysis decreases the peptide size and induces an increase in gliadin uptake and degradation. Deamidation and extensive enzymatic hydrolysis of gliadins modify their interaction with DCs, leading to alteration of their immunostimulatory capacity. These findings demonstrate the strong relationship between the biochemical characteristics of proteins and immune cell interactions.

In the present study, we investigate degradable anionic dendritic nanogels (DNG) as carriers for antimicrobial peptides (AMPs). In such systems, the dendritic part contains carboxylic acid-based anionic binding sites for cationic AMPs, whereas linear poly(ethylene glycol) (PEG) chains form a shell for promotion of biological stealth. In order to clarify factors influencing membrane interactions of such systems, we here address effects of nanogel charge, cross-linking, and degradation on peptide loading/release, as well as consequences of these factors for lipid membrane interactions and antimicrobial effects. The DNGs were found to bind the AMPs LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES) and DPK-060 (GKHKNKGKKNGKHNGWKWWW). For the smaller DPK-060 peptide, loading was found to increase with increasing nanogel charge density. For the larger LL-37, on the other hand, peptide loading was largely insensitive to nanogel charge density. In line with this, results on the secondary structure, as well as on the absence of stabilization from proteolytic degradation by the nanogels, show that the larger LL-37 is unable to enter into the interior of the nanogels. While 40-60% nanogel degradation occurred over 10 days, promoted at high ionic strength and lower cross-linking density/higher anionic charge content, peptide release at physiological ionic strength was substantially faster, and membrane destabilization not relying on nanogel degradation. Ellipsometry and liposome leakage experiments showed both free peptide and peptide/DNG complexes to cause membrane destabilization, indicated also by antimicrobial activities being comparable for nanogel-bound and free peptide. Finally, the DNGs were demonstrated to display low toxicity towards erythrocytes even at peptide concentrations of 100 µM.

International audience; Here we document the performance of a radiant cooling panel made of flow channels sandwiched between a suspended metal plate and an insulation layer. The flow passages represent the crucial element of the panel. In the present work, the heat transfer and flow characteristics of the panel are investigated. A numerical study is conducted to explore the role played by the flow architectures on the overall performance of the panel in steady state, subjected to radiation and convection heat fluxes from the bottom. A comparison between serpentine and canopy-to-canopy (dendritic) flow channels is presented. In all the cases, the following geometrical constrains apply: fixed plate area and flow volume. From one configuration to the other, the flow is given more freedom to morph in accord with the Constructal approach. We demonstrated that the dendritic architecture allows a significant improvement in the cooling panel performance, with more cooling capacity and less pumping power. In addition, we showed that the morphing of the panel itself toward more compactness is also a way to increase the ratio of cooling capacity/pumping power.

Dendritic growth of bismuth oxide nanostructured films was accomplished by reactive magnetron sputtering. The deposition of the Bi2O3 template layers was adapted to abide a vapour-liquid-solid mechanism in order to develop a 3D growth morphology with high surface area templates for photocatalytic applications. TiO2 photocatalytic thin films were deposited at a later stage onto Bi2O3 layers. The obtained heterostructured films were characterized by scanning electron microscopy, X-ray diffraction and atomic force microscopy. Additionally, the photocatalytic efficiency was assessed by conducting an assay using methylene blue dye as testing pollutant under a UV-A illumination. The photocatalytic tests revealed that the Bi2O3 layers functionalized with TiO2 thin films are more efficient at degrading the pollutant, by a factor of 6, when compared with the individual layered films., The authors acknowledge the funding from the Portuguese institution Fundacao para a Ciencia e Tecnologia, through the Strategic project reference UID/FIS/04650/2013, Ph.D grant SFRH/BD/111720/2015 for Filipe C. Correia and Ph.D grant SFRH/BD/112868/2015 Juliana Marques.

Thymic Stromal Lymphopoietin (TSLP) and Interleukin-7 (IL-7) are widely studied cytokines within distinct branches of immunology. On one hand, TSLP is crucially important for mediating type 2 immunity at barrier surfaces and has been linked to widespread allergic and inflammatory diseases of the airways, skin, and gut. On the other hand, IL-7 operates at the foundations of T-cell and innate lymphoid cell (ILC) development and homeostasis and has been associated with cancer. Yet, TSLP and IL-7 are united by key commonalities in their structure and the structural basis of the receptor assemblies they mediate to initiate cellular signaling, in particular their cross-utilization of IL-7R alpha. As therapeutic targeting of TSLP and IL-7 via diverse approaches is reaching advanced stages and in light of the plethora of mechanistic and structural data on receptor signaling mediated by the two cytokines, the time is ripe to provide integrated views of such knowledge. Here, we first discuss the major pathophysiological roles of TSLP and IL-7 in autoimmune diseases, inflammation and cancer. Subsequently, we curate structural and mechanistic knowledge about receptor assemblies mediated by the two cytokines. Finally, we review therapeutic avenues targeting TSLP and IL-7 signaling. We envision that such integrated view of the mechanism, structure, and modulation of signaling assemblies mediated by TSLP and IL-7 will enhance and fine-tune the development of more effective and selective approaches to further interrogate the role of TSLP and IL-7 in physiology and disease.

Heat shock proteins (HSP) are a highly abundant class of molecular chaperones that can be released into the extracellular milieu and influence the immune response. HSP release can occur when cells undergo necrosis and exude their contents. However, HSPs are also secreted from intact cells, either in free form or in lipid vesicles including exosomes to react with receptors on adjacent cells. Target cells are able recognize extracellular HSPs through cell surface receptors. These include scavenger receptors (SR) such as class E member oxidized low-density lipoprotein receptor-1 (LOX-1, aka OLR1, Clec8A, and SR-E1) and scavenger receptor class F member 1 (SCARF1, aka SREC1). Both receptors are expressed by dendritic cells (DC) and macrophages. These receptors can bind HSPs coupled to client binding proteins and deliver the chaperone substrate to the pathways of antigen processing in cells. SR are able to facilitate the delivery of client proteins to the proteasome, leading to antigen processing and presentation, and stimulation of adaptive immunity. HSPs may also may be involved in innate immunity through activation of inflammatory signaling pathways in a mechanism dependent on SR and toll-like receptor 4 (TLR4) on DC and macrophages. We will discuss the pathways by which HSPs can facilitate uptake of protein antigens and the receptors that regulate the ensuing immune response.

Les cèl·lules dendrítiques (DCs) són clau en la inducció de respostes immunitàries adaptatives gràcies a la seva capacitat de capturar, processar i presentar antígens derivats de patògens als limfòcits T. Tanmateix, aquestes cèl·lules podrien contribuir a la disseminació inicial del VIH-1 a través de la captura i transmissió viral a les cèl·lules T CD4+ diana, un procés conegut com a trans-infecció. Aquest mecanisme es basa en l'expressió del receptor Siglec-1 (CD169), que reconeix gangliòsids sialilats a la membrana viral. Els nivells de Siglec-1 augmenten en DCs estimulades amb interferó-alfa i lipopolisacàrid, factors immuno-activadors presents durant el decurs de la infecció per VIH-1. En aquesta tesi, hem demostrat que l'interferó-alfa secretat per DCs plasmacitoides (pDCs) infectades per VIH-1, així com l'inteferó-alfa autocrí secretat per cèl·lules mieloides en resposta a lipopolisacàrid, augmenten l'expressió de Siglec-1 en DCs. A més, les pDCs provinents de dones secreten quantitats superiors d'interferó-alfa que les d'homes, posant de manifest la rellevància d'estudiar la trans-infecció del VIH-1 en teixits clau per a l'adquisició del virus en dones. Així, també hem estudiat el paper de Siglec-1 en la transmissió del VIH-1 per part de DCs primàries aïllades directament de teixit cervical, identificant una població de cèl·lules mieloides cervicals que expressen Siglec-1 i capturen partícules de VIH-1 a través d'aquest receptor. Aquesta capacitat augmenta amb l'activació per interferó-alfa. A més, la transmissió del VIH-1 per cèl·lules mieloides del cèrvix es bloqueja de forma eficient amb un anticòs monoclonal dirigit contra Siglec-1. Per tant, hem generat una sèrie de nous anticossos monoclonals contra Siglec-1 amb la capacitat de bloquejar la tans-infecció del VIH-1 per DCs. S'han produït cinc nous clons, que han demostrat tenir una alta afinitat per diferents epítops localitzats a la regió N-terminal de Siglec-1. A més, aquests anticossos bloquegen la captura i trans-infecció del VIH-1 per DCs, de forma que podrien ser un component en estratègies microbicides dirigides contra aquest tipus de transmissió viral cèl·lula-cèl·lula. A banda del VIH-1, les cèl·lules dendrítiques participen en la patogènesi d'altres virus, com ara els filovirus d'Ebola i Marburg. A diferència del VIH-1, les DCs són permissives a la infecció per filovirus i són dianes primerenques en la patogènesi viral. Els factors cel·lulars implicats en l'entrada de filovirus en aquestes cèl·lules no han estat totalment caracteritzats, però tant Ebola com Marburg són virus embolcallats que incorporen gangliòsids sialilats durant el procés de gemmació viral. A més, els factors que activen l'expressió de Siglec-1 com ara interferó-alfa i lipopolisacàrid s'han trobat durant la infecció pel virus d'Ebola. Per tant, en aquesta tesi hem estudiat el paper de Siglec-1 en l'entrada de filovirus en DCs. Hem trobat que Siglec-1 està implicat en la captura de partícules no infeccioses d'Ebola per part d'aquestes cèl·lules, especialment després de l'activació per interferó-alfa i lipopolisacàrid. A més, les partícules capturades són acumulades en el mateix compartiment cel·lular en què prèviament s'havia detectat el VIH-1. Siglec-1 també facilita l'entrada citoplasmàtica del virus a les DCs, així que hem determinat la capacitat dels nous anticossos monoclonals contra Siglec-1 d'interferir amb aquest procés, i hem vist que aquests bloquegen tant la captura com l'entrada citoplasmàtica de partícules no infeccioses d'Ebola en cèl·lules mieloides activades. En general, l'activitat delsanticossos monoclonals contra Siglec-1 inhibeix l'accés de retrovirus i de filovirus a les cèl·lules mieloides, cosa que indica el seu potencial ús com a agents antivirals d'ampli espectre. Las células dendríticas (DCs) son clave en la inducción de respestas inmunitarias adaptativas gracias a su capacidad de capturar, procesar y presentar antígenos derivados de patógenos a los linfocitos T. Sin embargo, estas células también podrían contribuir a la diseminación inicial del VIH-1 a través de la captura de partículas virales y de su transmisión a las células T CD4+ diana, un proceso conocido como trans-infección. Este mecanismo se basa en la expresión del receptor Siglec-1 (CD169), que reconoce gangliósidos sialilados en la membrana viral. Los niveles de Siglec-1 aumentan en DCs estimuladas con interferón-alfa (IFN-α) y lipopolisacárido (LPS), factores immuno-activadores presentes durante el curso de la infección por VIH-1. En este trabajo, hemos demostrado que el IFN-α secretado por DCs plasmacitoides (pDCs) infectadas por VIH-1, así como el IFN-α autocrino secretado por células mieloides en respuesta a LPS, aumentan la expresión de Siglec-1 en DCs. Además, las pDCs provenientes de mujeres secretan cantidades superiores de IFN-α que las derivadas de hombres, poniendo de manifiesto la relevancia de estudiar la trans-infección del VIH-1 en tejidos clave para la adquisición del virus en mujeres. Por lo tanto, también hemos estudiado el papel de Siglec-1 en la transmisión del VIH-1 por parte de DCs primarias aisladas directamente de tejido cervical, identificando una población de DCs cervicales que expresan Siglec-1 y capturan partículas de VIH-1 a través de este receptor. Esta capacidad aumenta con la activación por IFN-α. Además, la transmisión célula-célula del VIH-1 por células mieloides del cérvix se puede bloquear de forma eficiente con un anticuerpo monoclonal (mAb) dirigido contra Siglec-1. Se han producido cinco nuevos clones, que han demostrado tener una alta afinidad por diferentes epítopos localizados en la región N-terminal de Siglec-1. Además, bloquean de forma eficaç la captura y trans-infección del VIH-1 por DCs, de forma que podrían ser un posible componente en estrategias microbicidas dirigidas contra este tipo de transmisión viral célula-célula. Además del VIH-1, las DCs pueden jugar un papel importante en la patogénesis de otros virus, como los filovirus Ébola y Marburg. A diferencia del VIH-1, las DCs son permisivas a la infección por filovirus y son dianas tempranas en lapatogénesis viral. Los factores celulares implicados en la entrada de filovirus en DCs no han sido totalmente caracterizados, pero tanto Ébola como Marburg son virus envueltos que incorporan gangliósidos sialilados durante el proceso de budding. Además, los factores que activan la expresión de Siglec-1 como IFN-α y LPS se han encontrado durante la infección por el virus de Ébola. Por tanto, en esta tesis hemos estudiado el papel de Siglec-1 en la entrada de filovirus en DCs. Hemos encontrado que Siglec-1 está implicado en la captura de partículas no infecciosas de Ébola (VLPs) por parte de estas células, especialmente tras la activación por IFN-α y LPS. Además, las VLPs capturadas se acumulan en el mismo compartimento en el que previamente se había detectado VIH-1. Siglec-1 también facilita la entrada citoplásmica del virus en las DCs, así que hemos determinado la capacidad de los nuevos mAbs contra Siglec-1 para interferir en este proceso, y hemos visto que dichos mAbs bloquean tanto la captura como la entrada citoplásmica de VLPs de Ébola en células mieloides activadas. En general, la actividad de los mAbs contra Siglec-1 inhibe el acceso de retrovirus y filovirus en las células mieloides, cosa que indica su potencial uso como agentes antivirales de amplio espectro. Dendritic cells are key inducers of specific adaptive immune responses due to their capacity to capture, process and present pathogen-derived antigens to T lymphocytes. However, they might also contribute to early HIV-1 dissemination by capturing HIV-1 particles and transmitting them to target CD4+ T cells, a process known as trans-infection. This mechanism relies on the expression of Siglec-1 receptor (CD169), which recognizes sialylated gangliosides on the viral membrane. Siglec-1 is potently up-regulated upon dendritic cell stimulation with interferon-alpha and lipopolysaccharide, which are both immune-activating factors present during the course of HIV-1 infection. Here, we demonstrated that interferon-alpha secreted by HIV-1-infected plasmacytoid dendritic cells and autocrine interferon-alpha secreted by myeloid cells in response to lipopolysaccharide up-regulate Siglec-1 on dendritic cells. Importantly, plasmacytoid dendritic cells derived from women secreted higher amounts of interferon-alpha than those derived from men, highlighting the relevance of studying HIV-1 trans-infection in key female tissues for HIV-1 acquisition. Thus, we next studied the role of Siglec-1 in HIV-1 transmission mediated by primary dendritic cells directly isolated from cervical tissues, identifying a subset of cervical myeloid cells that expressed Siglec-1 and captured HIV-1 particles in a Siglec-1-dependent manner. This capacity was enhanced upon activation with interferon-alpha. Moreover, HIV-1 cell-to-cell transmission mediated by these cells could be efficiently blocked using an anti-Siglec-1 monoclonal antibody, indicating the potential use of antibodies directed against Siglec-1 in prevention of sexually transmitted HIV-1 acquisition in women. Thus, we generated a set of new anti-Siglec-1 monoclonal antibodies with the capacity to block dendritic cell-mediated HIV-1 trans-infection. Five new clones were produced, demonstrating high affinity for different epitopes located in the N-terminal region of Siglec-1 receptor. Moreover, they efficiently blocked HIV-1 capture and trans-infection mediated by dendritic cells, indicating their potential use in microbicidal strategies targeting this type of viral cell-to-cell transmission. Aside from HIV-1, dendritic cells can play important roles in the pathogenesis of other viruses, including Ebola and Marburg filoviruses. In contrast to HIV-1, dendritic cells are permissive to filoviral infection and act as early targets in viral pathogenesis. The host factors governing filoviral entry into these cells are not fully characterized, but both Ebola and Marburg are enveloped viruses that incorporate sialylated gangliosides during the budding process. Moreover, Siglec-1-activating factors such as interferon-alpha and lipopolysaccharide have been found during Ebola virus disease. Thus, we investigated the role of Siglec-1 in filoviral entry into dendritic cells. We found that Siglec-1-mediated capture of non-infectious Ebola virus-like particles into these cells, especially upon interferon-alpha and lipopolysaccharide activation. Interestingly, captured Ebola virus-like particles accumulated in the same cellular compartment where HIV-1 was previously detected. Siglec-1 also facilitated Ebola cytoplasmic entry into dendritic cells, so we tested the capacity of novel anti-Siglec-1 monoclonal antibodies to interfere with this process. We found that capture and cytoplasmic entry of Ebola virus-like particles into activated myeloid cells was blocked by these novel antibodies. Overall, the activity of anti-Siglec-1 monoclonal antibodies inhibits the access of both retroviruses and filoviruses into myeloid cells and suggests their potential use as broad-spectrum antiviral agents.

Les cèl·lules dendrítiques (DCs) són clau en la inducció de respostes immunitàries adaptatives gràcies a la seva capacitat de capturar, processar i presentar antígens derivats de patògens als limfòcits T. Tanmateix, aquestes cèl·lules podrien contribuir a la disseminació inicial del VIH-1 a través de la captura i transmissió viral a les cèl·lules T CD4+ diana, un procés conegut com a trans-infecció. Aquest mecanisme es basa en l’expressió del receptor Siglec-1 (CD169), que reconeix gangliòsids sialilats a la membrana viral. Els nivells de Siglec-1 augmenten en DCs estimulades amb interferó-alfa i lipopolisacàrid, factors immuno-activadors presents durant el decurs de la infecció per VIH-1. En aquesta tesi, hem demostrat que l’interferó-alfa secretat per DCs plasmacitoides (pDCs) infectades per VIH-1, així com l’inteferó-alfa autocrí secretat per cèl·lules mieloides en resposta a lipopolisacàrid, augmenten l’expressió de Siglec-1 en DCs. A més, les pDCs provinents de dones secreten quantitats superiors d’interferó-alfa que les d’homes, posant de manifest la rellevància d’estudiar la trans-infecció del VIH-1 en teixits clau per a l’adquisició del virus en dones. Així, també hem estudiat el paper de Siglec-1 en la transmissió del VIH-1 per part de DCs primàries aïllades directament de teixit cervical, identificant una població de cèl·lules mieloides cervicals que expressen Siglec-1 i capturen partícules de VIH-1 a través d’aquest receptor. Aquesta capacitat augmenta amb l’activació per interferó-alfa. A més, la transmissió del VIH-1 per cèl·lules mieloides del cèrvix es bloqueja de forma eficient amb un anticòs monoclonal dirigit contra Siglec-1. Per tant, hem generat una sèrie de nous anticossos monoclonals contra Siglec-1 amb la capacitat de bloquejar la tans-infecció del VIH-1 per DCs. S’han produït cinc nous clons, que han demostrat tenir una alta afinitat per diferents epítops localitzats a la regió N-terminal de Siglec-1. A més, aquests anticossos bloquegen la captura i trans-infecció del VIH-1 per DCs, de forma que podrien ser un component en estratègies microbicides dirigides contra aquest tipus de transmissió viral cèl·lula-cèl·lula. A banda del VIH-1, les cèl·lules dendrítiques participen en la patogènesi d’altres virus, com ara els filovirus d’Ebola i Marburg. A diferència del VIH-1, les DCs són permissives a la infecció per filovirus i són dianes primerenques en la patogènesi viral. Els factors cel·lulars implicats en l’entrada de filovirus en aquestes cèl·lules no han estat totalment caracteritzats, però tant Ebola com Marburg són virus embolcallats que incorporen gangliòsids sialilats durant el procés de gemmació viral. A més, els factors que activen l’expressió de Siglec-1 com ara interferó-alfa i lipopolisacàrid s’han trobat durant la infecció pel virus d’Ebola. Per tant, en aquesta tesi hem estudiat el paper de Siglec-1 en l’entrada de filovirus en DCs. Hem trobat que Siglec-1 està implicat en la captura de partícules no infeccioses d’Ebola per part d’aquestes cèl·lules, especialment després de l’activació per interferó-alfa i lipopolisacàrid. A més, les partícules capturades són acumulades en el mateix compartiment cel·lular en què prèviament s’havia detectat el VIH-1. Siglec-1 també facilita l’entrada citoplasmàtica del virus a les DCs, així que hem determinat la capacitat dels nous anticossos monoclonals contra Siglec-1 d’interferir amb aquest procés, i hem vist que aquests bloquegen tant la captura com l’entrada citoplasmàtica de partícules no infeccioses d’Ebola en cèl·lules mieloides activades. En general, l’activitat delsanticossos monoclonals contra Siglec-1 inhibeix l’accés de retrovirus i de filovirus a les cèl·lules mieloides, cosa que indica el seu potencial ús com a agents antivirals d’ampli espectre. Las células dendríticas (DCs) son clave en la inducción de respestas inmunitarias adaptativas gracias a su capacidad de capturar, procesar y presentar antígenos derivados de patógenos a los linfocitos T. Sin embargo, estas células también podrían contribuir a la diseminación inicial del VIH-1 a través de la captura de partículas virales y de su transmisión a las células T CD4+ diana, un proceso conocido como trans-infección. Este mecanismo se basa en la expresión del receptor Siglec-1 (CD169), que reconoce gangliósidos sialilados en la membrana viral. Los niveles de Siglec-1 aumentan en DCs estimuladas con interferón-alfa (IFN-α) y lipopolisacárido (LPS), factores immuno-activadores presentes durante el curso de la infección por VIH-1. En este trabajo, hemos demostrado que el IFN-α secretado por DCs plasmacitoides (pDCs) infectadas por VIH-1, así como el IFN-α autocrino secretado por células mieloides en respuesta a LPS, aumentan la expresión de Siglec-1 en DCs. Además, las pDCs provenientes de mujeres secretan cantidades superiores de IFN-α que las derivadas de hombres, poniendo de manifiesto la relevancia de estudiar la trans-infección del VIH-1 en tejidos clave para la adquisición del virus en mujeres. Por lo tanto, también hemos estudiado el papel de Siglec-1 en la transmisión del VIH-1 por parte de DCs primarias aisladas directamente de tejido cervical, identificando una población de DCs cervicales que expresan Siglec-1 y capturan partículas de VIH-1 a través de este receptor. Esta capacidad aumenta con la activación por IFN-α. Además, la transmisión célula-célula del VIH-1 por células mieloides del cérvix se puede bloquear de forma eficiente con un anticuerpo monoclonal (mAb) dirigido contra Siglec-1. Se han producido cinco nuevos clones, que han demostrado tener una alta afinidad por diferentes epítopos localizados en la región N-terminal de Siglec-1. Además, bloquean de forma eficaç la captura y trans-infección del VIH-1 por DCs, de forma que podrían ser un posible componente en estrategias microbicidas dirigidas contra este tipo de transmisión viral célula-célula. Además del VIH-1, las DCs pueden jugar un papel importante en la patogénesis de otros virus, como los filovirus Ébola y Marburg. A diferencia del VIH-1, las DCs son permisivas a la infección por filovirus y son dianas tempranas en lapatogénesis viral. Los factores celulares implicados en la entrada de filovirus en DCs no han sido totalmente caracterizados, pero tanto Ébola como Marburg son virus envueltos que incorporan gangliósidos sialilados durante el proceso de budding. Además, los factores que activan la expresión de Siglec-1 como IFN-α y LPS se han encontrado durante la infección por el virus de Ébola. Por tanto, en esta tesis hemos estudiado el papel de Siglec-1 en la entrada de filovirus en DCs. Hemos encontrado que Siglec-1 está implicado en la captura de partículas no infecciosas de Ébola (VLPs) por parte de estas células, especialmente tras la activación por IFN-α y LPS. Además, las VLPs capturadas se acumulan en el mismo compartimento en el que previamente se había detectado VIH-1. Siglec-1 también facilita la entrada citoplásmica del virus en las DCs, así que hemos determinado la capacidad de los nuevos mAbs contra Siglec-1 para interferir en este proceso, y hemos visto que dichos mAbs bloquean tanto la captura como la entrada citoplásmica de VLPs de Ébola en células mieloides activadas. En general, la actividad de los mAbs contra Siglec-1 inhibe el acceso de retrovirus y filovirus en las células mieloides, cosa que indica su potencial uso como agentes antivirales de amplio espectro. Dendritic cells are key inducers of specific adaptive immune responses due to their capacity to capture, process and present pathogen-derived antigens to T lymphocytes. However, they might also contribute to early HIV-1 dissemination by capturing HIV-1 particles and transmitting them to target CD4+ T cells, a process known as trans-infection. This mechanism relies on the expression of Siglec-1 receptor (CD169), which recognizes sialylated gangliosides on the viral membrane. Siglec-1 is potently up-regulated upon dendritic cell stimulation with interferon-alpha and lipopolysaccharide, which are both immune-activating factors present during the course of HIV-1 infection. Here, we demonstrated that interferon-alpha secreted by HIV-1-infected plasmacytoid dendritic cells and autocrine interferon-alpha secreted by myeloid cells in response to lipopolysaccharide up-regulate Siglec-1 on dendritic cells. Importantly, plasmacytoid dendritic cells derived from women secreted higher amounts of interferon-alpha than those derived from men, highlighting the relevance of studying HIV-1 trans-infection in key female tissues for HIV-1 acquisition. Thus, we next studied the role of Siglec-1 in HIV-1 transmission mediated by primary dendritic cells directly isolated from cervical tissues, identifying a subset of cervical myeloid cells that expressed Siglec-1 and captured HIV-1 particles in a Siglec-1-dependent manner. This capacity was enhanced upon activation with interferon-alpha. Moreover, HIV-1 cell-to-cell transmission mediated by these cells could be efficiently blocked using an anti-Siglec-1 monoclonal antibody, indicating the potential use of antibodies directed against Siglec-1 in prevention of sexually transmitted HIV-1 acquisition in women. Thus, we generated a set of new anti-Siglec-1 monoclonal antibodies with the capacity to block dendritic cell-mediated HIV-1 trans-infection. Five new clones were produced, demonstrating high affinity for different epitopes located in the N-terminal region of Siglec-1 receptor. Moreover, they efficiently blocked HIV-1 capture and trans-infection mediated by dendritic cells, indicating their potential use in microbicidal strategies targeting this type of viral cell-to-cell transmission. Aside from HIV-1, dendritic cells can play important roles in the pathogenesis of other viruses, including Ebola and Marburg filoviruses. In contrast to HIV-1, dendritic cells are permissive to filoviral infection and act as early targets in viral pathogenesis. The host factors governing filoviral entry into these cells are not fully characterized, but both Ebola and Marburg are enveloped viruses that incorporate sialylated gangliosides during the budding process. Moreover, Siglec-1-activating factors such as interferon-alpha and lipopolysaccharide have been found during Ebola virus disease. Thus, we investigated the role of Siglec-1 in filoviral entry into dendritic cells. We found that Siglec-1-mediated capture of non-infectious Ebola virus-like particles into these cells, especially upon interferon-alpha and lipopolysaccharide activation. Interestingly, captured Ebola virus-like particles accumulated in the same cellular compartment where HIV-1 was previously detected. Siglec-1 also facilitated Ebola cytoplasmic entry into dendritic cells, so we tested the capacity of novel anti-Siglec-1 monoclonal antibodies to interfere with this process. We found that capture and cytoplasmic entry of Ebola virus-like particles into activated myeloid cells was blocked by these novel antibodies. Overall, the activity of anti-Siglec-1 monoclonal antibodies inhibits the access of both retroviruses and filoviruses into myeloid cells and suggests their potential use as broad-spectrum antiviral agents.

Electroacupuncture (EA) has been widely used for functional restoration after stroke. However, its role in post-stroke rehabilitation and the associated regulatory mechanisms remain poorly understood. In this study, we applied EA to the Zusanli (ST36) and Quchi (LI11) acupoints in rats with middle cerebral artery occlusion and reperfusion. We found that EA effectively increased the expression of brain-derived neurotrophic factor and its receptor tyrosine kinase B, synapsin-1, postsynaptic dense protein 95, and microtubule-associated protein 2 in the ischemic penumbra of rats with middle cerebral artery occlusion and reperfusion. Moreover, EA greatly reduced the expression of myelin-related inhibitors Nogo-A and NgR in the ischemic penumbra. Tyrosine kinase B inhibitor ANA-12 weakened the therapeutic effects of EA. These findings suggest that EA can improve neurological function after middle cerebral artery occlusion and reperfusion, possibly through regulating the activity of the brain-derived neurotrophic factor/tyrosine kinase B signal pathway. All procedures and experiments were approved by the Animal Research Committee of Shanghai University of Traditional Chinese Medicine, China (approval No. PZSHUTCM200110002) on January 10, 2020.

Type 2 inflammation is a defining feature of infection with parasitic worms(helminths), as well as being responsible for widespread suffering in allergies.However, the precise mechanisms involved in T helper (Th) 2 polarization bydendritic cells (DCs) are currently unclear. We have identified a previouslyunrecognized role for type I IFN (IFN-I) in enabling this process. An IFN-Isignature was evident in DCs responding to the helminth Schistosomamansoni or the allergen house dust mite (HDM). Further, IFN-I signaling wasrequired for optimal DC phenotypic activation in response to helminth antigen(Ag), and efficient migration to, and localization with, T cells in the draininglymph node (dLN). Importantly, DCs generated from Ifnar1-/- mice wereincapable of initiating Th2 responses in vivo. These data demonstrate for thefirst time that the influence of IFN-I is not limited to antiviral or bacterialsettings but also has a central role to play in DC initiation of Th2 responses.

Failure of uterine vascular transformation is associated with pregnancy complications including Intra Uterine Growth Restriction (IUGR). The decidua and its immune cell populations play a key role in the earliest stages of this process. Here we investigate the hypothesis that abnormal decidualization and failure of maternal immune tolerance in the second trimester may underlie the uteroplacental pathology of IUGR. Placental bed biopsies were obtained from women undergoing elective caesarian delivery of a healthy term pregnancy, an IUGR pregnancy or a pregnancy complicated by both IUGR and preeclampsia. Decidual tissues were also collected from second trimester terminations from women with either normal or high uterine artery Doppler pulsatile index (PI). Immunohistochemical image analysis and flow cytometry were used to quantify vascular remodeling, decidual leukocytes and decidual status in cases versus controls. Biopsies from pregnancies complicated by severe IUGR with a high uterine artery pulsatile index (PI) displayed a lack of: myometrial vascular transformation, interstitial and endovascular extravillous trophoblast (EVT) invasion, and a lower number of maternal leukocytes. Apoptotic mural EVT were observed in association with mature dendritic cells and T cells in the IUGR samples. 2nd trimester pregnancies with high uterine artery PI displayed a higher incidence of small for gestational age fetuses; a skewed decidual immunology with higher numbers of; CD8 T cells, mature CD83 dendritic cells and lymphatic vessels that were packed with decidual leukocytes. The decidual stromal cells failed to differentiate into the large secretory DSC in these cases, remaining small and cuboidal and expressing lower levels of the nuclear progesterone receptor isoform B, and decidual stromal cell markers Insulin Growth Factor Binding protein-1 (IGFBP-1) and CD10 as compared to controls. This study shows that defective progesterone mediated decidualization and a hostile maternal immune response against the invading endovascular EVT contribute to the failure of uterovascular remodelling in IUGR pregnancies.

Contains fulltext : 200170.pdf (Publisher’s version ) (Open Access) Background and objective: Diffuse intrinsic pontine glioma (DIPG) is a lethal brainstem tumor in children. Dendritic cells (DCs) have T-cell stimulatory capacity and, therefore, potential antitumor activity for disease control. DCs vaccines have been shown to reactivate tumor-specific T cells in both clinical and preclinical settings. We designed a phase Ib immunotherapy (IT) clinical trial with the use of autologous dendritic cells (ADCs) pulsed with an allogeneic tumors cell-lines lysate in patients with newly diagnosed DIPG after irradiation (radiation therapy). Methods: Nine patients with newly diagnosed DIPG met enrollment criteria. Autologous dendritic cell vaccines (ADCV) were prepared from monocytes obtained by leukapheresis. Five ADCV doses were administered intradermally during induction phase. In the absence of tumor progression, patients received three boosts of tumor lysate every 3 months during the maintenance phase. Results: Vaccine fabrication was feasible in all patients included in the study. Non-specific KLH (9/9 patients) and specific (8/9 patients) antitumor response was identified by immunologic studies in peripheral blood mononuclear cells (PBMC). Immunological responses were also confirmed in the T lymphocytes isolated from the cerebrospinal fluid (CSF) of two patients. Vaccine administration resulted safe in all patients treated with this schema. Conclusion: These preliminary results demonstrate that ADCV preparation is feasible, safe, and generate a DIPG-specific immune response detected in PBMC and CSF. This strategy shows a promising backbone for future schemas of combination IT.

The purpose of this work was to investigate the effect of multifunctionality on material properties of synthetic polymer aerogels. For this purpose, we present the synthesis and characterization of monolithic dendritic-type urethane-acrylate monomers based on an aliphatic/flexible (Desmodur N3300), or an aromatic/rigid (Desmodur RE) triisocyanate core. The terminal acrylate groups (three at the tip of each of the three branches, nine in total) were polymerized with 2,2&prime, azobis(isobutyronitrile) (AIBN) via free radical chemistry. The resulting wet-gels were dried with supercritical fluid (SCF) CO2. Aerogels were characterized with ATR-FTIR and solid-state 13C NMR. The porous network was probed with N2-sorption and scanning electron microscopy (SEM). The thermal stability of aerogels was studied with thermogravimetric analysis (TGA). Most aerogels were macroporous materials (porosity &gt, 80%), with high thermal stability (up to 300 &deg, C). Aerogels were softer at low monomer concentrations and more rigid at higher concentrations. The material properties were compared with those of analogous aerogels bearing only one acrylate moiety at the tip of each branch and the same cores, and with those of analogous aerogels bearing norbornene instead of acrylate moieties. The nine-terminal acrylate-based monomers of this study caused rapid decrease of the solubility of the growing polymer and made possible aerogels with much smaller particles and much higher surface areas. For the first time, aliphatic/flexible triisocyanate-based materials could be made with similar properties in terms of particle size and surface areas to their aromatic/rigid analogues. Finally, it was found that with monomers with a high number of crosslinkable groups, material properties are determined by multifunctionality and thus aerogels based on 9-acrylate- and 9-norbornene-terminated monomers were similar. Materials with aromatic cores are carbonizable with satisfactory yields (20&ndash, 30% w/w) to mostly microporous materials (BET surface areas: 640&ndash, 740 m2 g&minus, 1, micropore surface areas: 360&ndash, 430 m2 g&minus, 1).

The microstructural evolution during varying thermal gradients of rheocast AA7075 aluminium alloy was investigated. To perform this study, semi-solid billets of non-dendritic microstructure were produced using Linear Electro Magnetic Stirrer (LEMS). Gas Tungsten arc welding (GTAW) was conducted to simulate varying thermal gradients near fusion zone. Welding simulations were performed using SYSWELD®. Quantitative metallography was used to aid the analysis. Numerical simulations and quantitative results show that the width of the partially melted zone (PMZ) plays a vital role in the nucleation mechanism and dendritic microstructure formation in this class of alloys.

Lentiviral vectors (LVs) developed in the past two decades for research and pre-clinical purposes have entered clinical trials with remarkable safety and efficacy performances. Development and clinical testing of LVs for improvement of human immunity showed major advantages in comparison to other viral vector systems. Robust and persisted transduction efficiency of blood cells with LVs, resulted into a broad range of target cells for immune therapeutic approaches: from hematopoietic stem cells and precursor cells for correction of immune deficiencies, up to effector lymphoid and myeloid cells. T cells engineered for expression of chimeric antigen receptors (CARs) or epitope-specific transgenic T cell receptors (TCRs) are in several cancer immune therapy clinical trials worldwide. Development of engineered dendritic cells is primed for clinical trials for cancer and chronic infections. Technological adaptations for ex vivo cell manipulations are here discussed and presented based on properties and uses of the target cell. For future development of off-shelf immune therapies, direct in vivo administration of lentiviral vectors is warranted and intended. Approaches for lentiviral in vivo targeting to maximize immune therapeutic success are discussed.

Volume 8: Heat Transfer and Thermal EngineeringPhoenix, Arizona, USA, November 11–17, 2016Conference Sponsors: ASMEISBN: 978-0-7918-5062-6; International audience; In this paper we report the main advances made by our research group on the heat transfer performance of complex stream architectures embedded in a conducting solid. The immediate application of this review work deals with ground coupled heat pumps. Various configurations are considered: U-shaped with varying spacing between the parallel portions of the U, serpentines with three elbows, and trees with T- and Y-shaped bifurcations. In each case the volume ratio of fluid to soil is fixed. We determine the critical geometric features that allow the heat transfer density of the stream-solid configuration to be the highest that it can be. In the case of U-tubes and serpentines, the best spacing between parallel portions is discovered, whereas the vascular designs morph into bifurcations and angles of connection that provide progressively greater heat transfer rate per unit volume. Next we move to more complex underground structures, connecting several heat pumps to the same fluid loop. We conclude by comparing the merits of the two options.

The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, we present novel halogen-free aromatic and aliphatic hyperbranched polyphosphoesters (hbPPEs), which were synthesized by olefin metathesis polymerization and investigated them as a FR in epoxy resins. We compare their efficiency (aliphatic vs. aromatic) and further assess the differences between the monomeric compounds and the hbPPEs. The decomposition and vaporizing behavior of a compound is an important factor in its flame-retardant behavior, but also the interaction with the pyrolyzing matrix has a significant influence on the performance. Therefore, the challenge in designing a FR is to optimize the chemical structure and its decomposition pathway to the matrix, with regards to time and temperature. This behavior becomes obvious in this study, and explains the superior gas phase activity of the aliphatic FRs.

WOS:000312625200047; International audience; Here we document comparatively the performance of three flow architectures for heat transfer between a buried flow structure and a conducting medium: trees with Y-shaped bifurcations, trees with T-shaped bifurcations, and classical U-shaped and serpentine designs. The competing designs occupy the same volume fraction. The tree architectures have up to four levels of bifurcation (N). We found that the heat transfer performance depends greatly on the flow configuration. The tree shaped designs yield improvements in heat transfer density as N increases from 0 to 4. The Y-shaped design is the best of the three architectures. The scale analysis of tree-in-solid heat transfer anticipates correctly the key features of the thermal performance of the architecture. The paper also shows that the tree architecture, which is derived from minimizing flow resistance, also has the property that it distributes uniformly the flow resistance time throughout the structure. This is true for both laminar and turbulent flow. (C) 2012 Elsevier Ltd. All rights reserved.

Identifying the processes and mechanisms that govern communities of organisms is the main goal of community ecology. Locally operating mechanisms such as environmental filtering, in which the environment determines what species are found in a given location, as well as regional processes such as dispersal have all been identified as potential drivers of community processes. However, the relative importance of these drivers may vary temporally and spatially. In dendritic stream networks, headwater streams are isolated when compared to more centrally located mainstem stream sections. I investigated the potential for stream networks to influence the relative influence of local and regional processes via a survey and field experiment based approaches. I found that headwater streams can influence mainstem stream communities, potentially as a result of the dispersal of organisms or abiotic materials. Additionally, I demonstrated that macroinvertebrate communities in headwater streams respond more strongly to manipulations of local environment than do mainstem streams, both in terms of community composition as determined taxonomically and as functional traits. These results indicate that headwater streams may be affected differently than mainstem streams by anthropogenic activity and as such, management strategies and restorations may need to be specifically tailored to address the relative influences of local and regional processes at varying points within a stream network. Ph. D.

Objectives Establishing fast sensitive methods to remove, detect and quantify traces of diethanolamine (DEA) from Generation 1 DEA terminated dendrimers (G1-OH) as a model for hydroxyl terminated dendrimers. Methods The method is based on a relatively recent ultra Performance liquid chromatography electro spray ionization time of flight mass spectroscopy (UPLC-ESI-TOF-MS). Results Small dendrimers with surface hydroxyl groups were cleaned by dialysis and traces of DEA (1.9 ng) was detected and measured. The total UPLC-ESI-TOF-MS run time was 10 minutes. The amount of dendrimers required for the analysis was 50 ng/injection. The volume of the mobile phase used was 1.5ml/run. Conclusion The present study reports a fast sensitive method for the separation and determination of traces of free DEA molecules (have no natural chromophores or fluorophores) in small dendritic nano molecules by UPLC ESI TOF MS with very small volumes of commercially available reagents.

Dendritic landscapes can have ecological properties that differ importantly from simpler spatial arrangements of habitats. Most dendritic landscapes are structured by elevation, and therefore, migration is likely to be directionally biased. While the population‐genetic consequences of both dendritic landscape arrangements and asymmetric migration have begun to be studied, these processes have not been considered together. Simple conceptual models predict that if migration into branch (headwater) populations is limited, such populations can act as reservoirs for potentially unique alleles. As a consequence of the fact that dendritic landscapes have, by definition, more branches than internal habitat patches, this process may lead to the maintenance of higher overall genetic diversities in metapopulations inhabiting dendritic networks where migration is directionally biased. Here we begin to address the generality of these simple predictions using genetic models and a review of empirical literature. We show, for a range of demographic parameters, that dendritic systems with asymmetric migration can maintain levels of genetic variation that are very different, sometimes very elevated, compared with more classical models of geographical population structure. Furthermore, predicted patterns of genetic variation within metapopulations—that is, stepwise increases in genetic diversity at nodes—do occur in some empirical data. Publisher PDF

A constructaltree-shaped microchannel network for maximizing the saturated critical heat flux in a disc-shaped planar body has been investigated. n(0) radial channels touch the center and n(p) channels touch the periphery. Designs with no pairing level (n(0) = n(p)), one pairing level (2n(0) = n(p)) and two pairing levels (4n(0) = n(p)) have been studied. The fluid simulated is R-134a at a saturation temperature of T-sat = 30 degrees C with no inlet subcooling. The flow enters at the center and exits at the periphery. The theoretical CHF model of Revellin and Thome [R. Revellin, J.R. Thome, A theoretical model for the prediction of the critical heat flux in heated microchannels, Int. J. Heat Mass Transfer 51 (2008) 1216-1225], specially developed for micro and minichannels, has been modified and used for predicting the wall CHF of low pressure refrigerants flowing in microchannels. The constraints are the disc radius R and the total volume of ducts V. The degrees of freedom are n(0), n(p) and the mass flow rate m. In each case, the minimum global fluid flow resistance design has been adopted as proposed by Wechsatol et al. [W. Wechsatol, S. Lorente, A. Bejan, Optimal tree-shaped networks for fluid flow in a disc-shaped body, Int. J. Heat Mass Transfer 45 (2002) 4911-4924]. Maximizing the base CHF means increasing the number of central tubes for a given complexity. Furthermore, it is better to use a simple radial structure (with no pairing level) and 2n(0) central tubes than a design with one pairing level and n(0) central tubes. On one hand, simplified structures seem to be roughly better for maximizing the base CHF. On the other hand, coupling the base CHF and the pumping power leads to different conclusions. There exists an optimal n(0) and n(p) to maximize the base CHF for each range of pumping power. For instance, for low pumping power, using radial ducts without pairing level is the best solution for dissipating high base CHF whereas for higher pumping power, a more complex design is beneficial with greater n(p). In conclusion, the recommended complexity is modest (not maximal), and high complexity is not necessarily the best solution. (C) 2008 Elsevier Masson SAS. All rights reserved.

We have previously reported a novel (albeit modestly successful) strategy for the synthesis of polystyrene HyperMacs – long chain branched analogues of hyperbranched polymers. The building blocks for HyperMacs, AB2 macromonomers are synthesized by living anionic polymerization and as such are well-defined in terms of molecular weight and polydispersity but the nature of the coupling reaction used to generate the highly branched HyperMacs results in branched polymers with a distribution of molecular weights and architectures. In our previously reported studies the extent of the coupling reaction was significantly hampered by side reactions, however, we report here dramatic improvements to the coupling chemistry which overcome the previously experienced limitations resulting in a fourfold increase in the extent of the coupling reactions. Furthermore we report the effect of the addition of varying amounts of a B3 core molecule to the coupling reaction and the resultant ‘control’ of the final molecular weight of the HyperMac. Melt rheology showed polystyrene HyperMacs to be thermorheologically simple, obeying William–Landel–Ferry (WLF) behaviour. HyperMacs showed little evidence for relaxation by reptation and when the molecular weight of the macromonomer was ⩽Me for polystyrene, HyperMacs resemble unentangled polymers below the gel point, despite being well above the entanglement molecular weight for linear polystyrene. Increasing the molecular weight of the macromonomer to substantially above Me seems to introduce some entangled nature to the HyperMac as evidenced by the emergence of a near horizontal plateau in G″ – the loss modulus.

STUDY QUESTION: Could seminal plasma clusterin play a role in the uptake of stress-damaged proteins by dendritic cells? SUMMARY ANSWER: Seminal plasma clusterin, but not serum clusterin, promotes the uptake of stress-damaged proteins by dendritic cells via DC-SIGN. WHAT IS KNOWN ALREADY: Clusterin is one of the major extracellular chaperones. It interacts with a variety of stressed proteins to prevent their aggregation, guiding them for receptor-mediated endocytosis and intracellular degradation. The concentration of clusterin in semen is almost 20-fold higher than that found in serum, raising the question about the role of seminal plasma clusterin in reproduction. No previous studies have analyzed whether seminal plasma clusterin has chaperone activity. We have previously shown that seminal plasma clusterin, but not serum clusterin, expresses an extreme abundance of fucosylated glycans. These motifs enable seminal plasma clusterin to bind DC-SIGN with very high affinity. STUDY DESIGN, SIZE, DURATION: In vitro experiments were performed to evaluate the ability of seminal plasma clusterin to inhibit the precipitation of stressed proteins, promoting their uptake by dendritic cells via DC-SIGN (a C-type lectin receptor selectively expressed on dendritic cells (DC)). Moreover, the ability of seminal plasma clusterin to modulate the phenotype and function of DCs was also assessed. PARTICIPANTS/MATERIALS, SETTING, METHODS: Clusterin was purified from human semen and human serum. Catalase, bovine serum albumin, glutathione S-transferase, and normal human serum were stressed and the ability of seminal plasma clusterin to prevent the precipitation of these proteins, guiding them to DC-SIGN expressed by DCs, was evaluated using a fluorescence-activated cell sorter (FACS). Endocytosis of stressed proteins was analyzed by confocal microscopy and the ability of seminal plasma clusterin-treated DCs to stimulate the proliferation of CD25+FOXP3+CD4+ T cells was also evaluated by FACS. MAIN RESULTS AND THE ROLE OF CHANCE: Seminal plasma clusterin interacts with stressed proteins, inhibits their aggregation (P < 0.01) and efficiently targets them to dendritic cells via DC-SIGN (P < 0.01). DCs efficiently endocytosed clusterin-client complexes and sorted them to degradative compartments involved in antigen processing and presentation. Moreover, we also found that the interaction of seminal plasma clusterin with DC-SIGN did not change the phenotype of DCs, but stimulates their ability to induce the expansion of CD25+FOXP3+CD4+ T lymphocytes (P < 0.05 versus control). LIMITATIONS, REASONS FOR CAUTION: All the experiments were performed in vitro; hence the relevance of our observations should be validated in vivo. WIDER IMPLICATIONS OF THE FINDINGS: Our results suggest that by inducing the endocytosis of stress-damaged proteins by DCs via DC-SIGN, seminal plasma clusterin might promote a tolerogenic response to male antigens, thereby contributing to female tolerance to seminal antigens. STUDY FUNDING/COMPETING INTEREST(S): The present research was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas, the Buenos Aires University School of Medicine, and the Agencia Nacional de Promoción Científica y Tecnológica (Argentina). The authors have no conflicts of interest to declare. Fil: Merlotti Ippólito, Antonela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentina Fil: Dantas, Ezequiel Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina Fil: Remes Lenicov, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina Fil: Ceballos, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina Fil: Jancic, Carolina Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina Fil: Varese, Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina Fil: Rubione, Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina Fil: Stover, Juliana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina Fil: Geffner, Jorge Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina Fil: Sabatte, Juan Atilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina

Rett Syndrome (RTT) is a neurodevelopmental disorder associated with intellectual disability, mainly caused by loss-of-function mutations in the MECP2 gene. RTT brains display decreased neuronal size and dendritic arborisation possibly caused by either a developmental failure or a deficit in the maintenance of dendritic arbour structure. To distinguish between these two hypotheses, the development of Mecp2-knockout mouse hippocampal neurons was analyzed in vitro. Since a staging system for the in vitro development of mouse neurons was lacking, mouse and rat hippocampal neurons development was compared between 1-15 days in vitro (DIV) leading to a 6-stage model for both species. Mecp2-knockout hippocampal neurons displayed reduced growth of dendritic branches from stage 4 (DIV4) onwards. At stages 5-6 (DIV9-15), synapse number was lowered in Mecp2-knockout neurons, suggesting increased synapse elimination. These results point to both a developmental and a maintenance setback affecting the final shape and function of neurons in RTT.

Neurotrophins are involved in many crucial cellular functions, including neurite outgrowth, synapse formation, and plasticity. Although these events have long been known, the molecular determinants underlying neuritogenesis have not been fully characterized. Ack1 (activated Cdc42-associated tyrosine kinase) is a non-receptor tyrosine kinase that is highly expressed in the brain. Here, we demonstrate that Ack1 is a molecular constituent of neurotrophin signaling cascades in neurons and PC12 cells. We report that Ack1 interacts with Trk receptors and becomes tyrosine phosphorylated and its kinase activity is increased in response to neurotrophins. Moreover, our data indicate that Ack1 acts upstream of the Akt and MAPK pathways. We show that Ack1 overexpression induces neuritic outgrowth and promotes branching in neurotrophin-treated neuronal cells, whereas the expression of Ack1 dominant negatives or short-hairpin RNAs counteract neurotrophin-stimulated differentiation. Our results identify Ack1 as a novel regulator of neurotrophin-mediated events in primary neurons and in PC12 cells.

“Dendritic valley networks” and broad “longitudinal valleys” are widespread within the eastern Libya Montes region. The morphologic characteristics of the studied dendritic valleys, especially their occurrence at local summits, provide evidence for the initial formation by surface runoff due to atmospheric precipitation whereas the longitudinal valley systems are thought to have been formed and modified by groundwater-induced processes. Our crater counts and model ages show, that the dendritic valley networks (average age ∼ 4.0 Ga) formed earlier than the longitudinal valley systems (average age ∼ 3.7 Ga). Both fluvial forms indicate a temporal change of the erosive environment at the Noachian/Hesperian transition at ∼ 3.8 Ga. Our results suggest that the fluvial activity within our investigation area lasted for ∼ 800 My, from ∼ 4.1 Ga to ∼ 3.3 Ga. The dendritic valleys show valley densities between 0.12 km− 1 and 0.57 km− 1, indicative of highly mature and integrated valley systems that we interpret to be characteristic of warmer and wetter conditions on Mars.

Little is known about the impact ectopically located neurons have on the functional connectivity of local circuits. The ApoER2 knockout mouse has subtle cytoarchitectural disruptions, altered prepulse inhibition, and memory abnormalities. We evaluated this mouse mutant as a model to study the role ectopic neurons play in the manifestation of symptoms associated with brain diseases. We found that ectopic CA1 pyramidal and inhibitory neurons in the ApoER2 knockout hippocampus are organized into two distinct stratum pyramidale layers. In vitro analyses found that ApoER2 is not required for neurons to reach maturity in regards to dendritic arborization and synaptic structure density, and electrophysiological testing determined that neurons in both strata pyramidale are integrated into the hippocampal network. However, the presence of these two layers alters the spatiotemporal pattern of hippocampal activity, which may explain why ApoER2 knockout mice have selective cognitive dysfunctions that are revealed only under challenging conditions.

Many previous studies of biological activity in a homologous series of amphiphiles have shown a cut-off effect, where the biological activity increases with an increase in chain length, after which the activity plateaus or weakens. One factor suspected to cause this problem is solubility issues. We have designed several series of very hydrophobic, water-soluble amphiphiles to overcome this problem. Three homologous series containing mobile hydrophobic moieties and two series of epimers containing rigid cholestane moieties have been synthesized; the hydrophobic moiety is connected to the first-generation, Newkome-type dendron via a ureido linker. We have demonstrated that as tris(triethanolammonium) salts, these amphiphiles show excellent solubility in water. The solubilities in aqueous triethanolamine solution of the three series containing mobile hydrophobic moieties are 19,500 to 25,700 μM depending on the formula weight of the homolog, while those containing rigid cholestane moieties are 18,900 and 17,400 μM. Having eliminated the solubility issue, the antimicrobial activity against a broad spectrum of microorganisms has been screened. We have demonstrated that the antimicrobial activity depends on the amphiphile-series, species, chain-length, or epimer specificities, as well as hydrophobicity. The one-tailed, tri-carboxylato amphiphiles are generally better than the other series, with two exceptions. First, the two-tailed tri-carboxylato amphiphiles, 3CUr1(11)₂ and 3CUr1(12)₂, are more active against Cryptococcus neoformans; in fact, both amphiphiles (MICs are 6.9 and 7.2 μM, respectively) are considered to display good antifungal activity. Second, amphiphile 3CUr-β-cholestane, whose MIC is 27 μM, is more active against Staphylococcus aureus. Overall, these new tri-carboxylato amphiphiles only exhibit moderate activity with two promising leads. Furthermore, we have demonstrated the intrinsic activity (MIC₀) of the one-tailed, tri-carboxylato amphiphile series (3CUrn) against Mycobacterium smegmatis. All the MIC₀s observed are at least 8-fold lower than the corresponding CMCs. Amphiphile 3CUr16 is the most active; the MIC₀ is 100-fold smaller than the CMC. With this consideration, we have suggested that the mechanism of action of the antimycobacterial activity in amphiphile 3CUr16 is not related to detergency. Ph. D.

0\. Titelblatt und Inhaltsverzeichnis 1\. Einleitung 1 2\. Material und Methoden 17 3\. Ergebnisse 38 4\. Diskussion 75 5\. Zusammenfassung 89 6\. Referenzen 91 7\. Anhang 101, Die vorliegende Arbeit beschreibt erstmals die Expression, Funktion und Regulation des ICOS-L auf Subtypen Dendritischer Zellen (DZ) im Mausmodell. Insbesondere wird dies im Kontext einer Infektion mit dem (murinen) Zytomegalovirus (MCMV) analysiert. ICOS-L ist der Ligand des T-Zell (TZ) Kostimulators ICOS (Inducible Costimulator) und besitzt als Mitglied der B7-Familie Homologie zu CD80 und CD86. Zunächst wurden Methoden zur Aufreinigung muriner DZ-Subtypen im Labor etabliert. Untersuchungen in der Durchflusszytometrie zeigten, dass das Molekül auf DZ-Subpopulationen aus der Milz exprimiert wird. Durch Experimente mit Blockadereagenzien bzw. T‑Zellen aus ICOS-defizienten Mäusen wurde nachgewiesen, dass die ICOS/ICOS-L-Interaktion während der primären Stimulation antigenspezifischer TZ durch DZ in vitro die Produktion von IFN‑γ und IL‑10 hemmt. Nach Restimulation führt die ICOS-Stimulation der TZ zu einer erniedrigten Produktion von IFN-γ und einer erhöhten Produktion von IL-4, also zu einer Th2-gerichteten Zytokinausschüttung. Zahlreiche Faktoren, die sich auf die Expression des ICOS-L auf DZ auswirken und somit möglicherweise eine Immunantwort modifizieren könnten, wurden identifiziert. Dazu gehören Zytokine wie IFN-γ und GM-CSF, die die ICOS-L-Expression hemmen können. Besonders aufgefallen ist das murine Zytomegalovirus (MCMV) als ein komplexes Pathogen, das die Expression des ICOS-L auf der Zelloberfläche infizierter DZ herunterregulierte. Durch die systematische Analyse von MCMV-Mutanten konnte das bisher als viraler Fcg-Rezeptor (Fcγ-R) bekannte Molekül fcr-1/m138 als Regulator der ICOS-L-Expression auf der Oberfläche MCMV-infizierter Zellen identifiziert werden. Die Relevanz des ICOS/ICOS-L-Systems für die Immunantwort bei MCMV-Infektion wurde durch Untersuchungen von ICOS- defizienten Mäusen deutlich bestätigt: Sie weisen bei sublethaler MCMV- Infektion gegenüber WT-Tieren eine deutlich verzögerte Eliminierung von produktivem Virus aus infizierten Organen auf. Mit der viralen Modulation der Expression des ICOS-L auf infizierten Zellen durch m138/fcr-1 wurde ein neuer wichtiger Mechanismus der Immunevasion von MCMV und eine weitere Funktion dieses viralen Fcγ‑R identifiziert. Ferner wurde mit m138/fcr-1 erstmalig ein viraler Regulator der ICOS-L-Expression beschrieben., This work describes for the first time the expression, function and regulation of ICOS-L on subpopulations of murine dendritic cells (DC). This has been analysed particularely in the context of murine cytomegalovirus (MCMV) infection. ICOS-L is the ligand of the T-cell- (TC) costimulatory molecule ICOS (inducible costimulator) and is structurally related to CD80 and CD86. Initially, methods for the purification of murine DC-subpopulations have been succesfully established in the laboratory. Flow cytometry studies revealed that all DC-supopulations from the murine spleen express ICOS-L. Experiments with blocking reagents or TC from ICOS-deficient mice provided evidence that the ICOS/ICOS-L-interaction during primary stimulation of TC by DC inhibits the production of IL-10 and IFN-γ. Furthermore, ICOS-mediated restimulation of the TC led to a reduced production of IFN-γ and an increased production of IL-4, suggesting a Th2-biased cytokine production. Many factors that influence the expression of ICOS-L on DC and that therefore may alter an immune-response have been identified by in vitro experiments. These factors include cytokines like IFN-γ and GM-CSF that can inhibit the expression of ICOS-L. Especially a complex pathogen, MCMV, attracted our attention as a regulator of the expression of ICOS L on murine DC. In a systematic approach, based on a panel of MCMV gene-deletion mutants we identified fcr-1/m138, a molecule known as a virally encoded Fc-receptor, as a regulator of the ICOS-L-expression on MCMV- infected cells. Studies with ICOS-deficient mice corroborated the important role of the ICOS/ICOS-L-system during the immune-response against an MCMV infection: ICOS-deficient mice show a clearly delayed elimination of productive virus from infected organs compared to wildtype mice. With the modulation of the ICOS-L-expression on infected cells by fcr-1/m138, a new mechanism for the immune-evasion of MCMV has been identified. Furthermore, our data demonstrate that besides its Fc-binding properties fcr-1/m138 has a new role as a modulator of cell surface proteins. In conclusion, the present work presents the first description of a viral regulator for ICOS-L.

An illustrated glossary of terms used in the analysis of the shells of recent and fossil foraminifera supplemented by a rigorous selection of terms that facilitate an understanding of their biology and their use in ecology and biostratigraphy. The glossary includes some 650 entries illustrated by 83 - often composite – figures many of which are stereographs or 3D models. A taxonomic index lists the 140 taxa illustrated.

Three Pd-Cu-Ga alloys with as-cast dendritic microstructures and very similar compositions, two containing less than 1 wt% boron and the third boron-free, were cast with normal bench-cooling or rapid-quenching into water. Quenched specimens were also heat treated at temperatures of 1000°, 1200°, 1500° and 1800°F that span the firing cycles for dental porcelain. Similar values of Vickers hardness were observed for all three alloys, suggesting little effect from boron on yield strength. The hardness was relatively insensitive to the experimental conditions, except for heat treatment at 1500° and 1800°F where significant softening occurred with transformation of the microstructure to Pd2Ga and the palladium solid solution.

Using a rheometer coupled with an UV-light generator, the viscoelastic behaviour during the fast cure of star-branched polyester is investigated. The 32 arm star polymers consist of a hyperbranched polyester core, BoltornTM and linear grafts of poly(E-caprolactone) (degree of polymerisation: 20.52) with methacrylate end groups. The resins are crystalline and the melting points range from 34 to 50 .C; films can be formed and cured below 80 .C. The crossover of G. and G.. was used as the gel point. The time to reach the gel point, a few seconds, increases linearly with molecular weight.

Autism is well known as a complex developmental disorder with a seemingly confusing and uncertain pathogenesis. The definitive mechanisms that promote autism are poorly understood and mostly unknown, yet available theories do appear to focus on the disruption of normal cerebral development and its subsequent implications on the functional brain unit. This mini-review aims solely to discuss and evaluate the most prominent current theories regarding the pathogenesis of autism. The main conclusion is that although there is not a clear pathway of mechanisms directed towards a simple pathogenesis and an established link to autism on the symptomatic level; there are however several important theories (neural connectivity, neural migration, excitatory-inhibitory neural activity, dendritic morphology, neuroimmune; calcium signalling and mirror neurone) which appear to offer an explanation to how autism develops. It seems probable that autism's neurodevelopmental defect is ‘multi-domain’ in origin (rather than a single anomaly) and is hence distributed across numerous levels of study (genetic, immunopathogenic, etc.). A more definitive understanding of the pathogenesis could facilitate the development of better treatments for this complex psychiatric disorder.