2,670 research outputs found
Electric-field-induced strain mechanisms in lead-free 94%(Bi1/2Na1/2)TiO3-6%BaTiO3
High resolution neutron diffraction has been used to investigate the structural origin of the large electric-field-induced remanent strain in 94(Bi1/2Na1/2)TiO3-6BaTiO(3) ceramics. The virgin material was found to be a mixture of near-cubic phases with slight tetragonal and rhombohedral distortions of a(0)a(0)c(+) and a(-)a(-)a(-) octahedral tilt type, respectively. Application of an electric field of 4.57 kV/mm transformed the sample to a predominantly rhombohedral a(-)a(-)a(-) modification with a significantly higher degree of structural distortion and a pronounced preferred orientation of the c-axis along the field direction. These electric field-induced structural effects contribute significantly to the macroscopic strain and polarization of this system.open40
Stromal cells promote anti-estrogen resistance of breast cancer cells through an insulin-like growth factor binding protein 5 (IGFBP5)/B-cell leukemia/lymphoma 3 (Bcl-3) axis
There is strong evidence that stromal cells promote drug resistance of cancer. Here, we show that mesenchymal stem cells (MSCs) and carcinoma-associated fibroblasts (CAFs) desensitize ERa-positive breast cancer cells to the anti-estrogen fulvestrant. In search for the mechanism, we found that MSCs and CAFs similarly increased the activity of the PI3K/AKT and the JAK/STAT3 pathways and upregulated the expression of integrin ß1, IGF1R, HIF1α, CAIX and Bcl-3 in MCF-7 cells. Further analyses revealed that MSCs and CAFs coordinately induce these changes by triggering the downregulation of IGFBP5. Loss of IGFBP5 in MCF-7 cells was an early and long-lasting event in response to MSCs and CAFs and was accompanied by growth stimulation both in the absence and presence of fulvestrant. The growth-stimulatory effect in the absence of fulvestrant could be attributed to PI3K/AKT pathway activation and could be mimicked by insulin. The growth-promoting effect in the presence of fulvestrant depended upon the upregulation of Bcl-3. By cRNA microarray analysis we identified additional IGFBP5 targets, of which two (KLHL4 and SEPP1) were inversely regulated by IGFBP5 and Bcl-3. BT474 cells also responded to stromal cells by downregulating IGFBP5 and upregulating the P-AKT, Bcl-3 and IGF1R levels, whereas T47D cells did not show any of these responses. In conclusion, our data suggest that, by targeting IGFBP5 expression in ERa-positive breast cancer cells, such as MCF-7 cells, MSCs and CAFs are able to orchestrate a variety of events, particularly activation of the PI3K/AKT pathway, upregulation of Bcl-3 expression and desensitization to anti-estrogen
Influence of antigen distribution on the mediation of immunological glomerular injury
Influence of antigen distribution on the mediation of immunological glomerular injury. To determine if the site of immune reaction could influence the mediation and morphological expression of glomerular injury in experimental anti-glomerular basement membrane (anti-GBM) nephritis and membranous nephropathy, we studied the events that followed the in situ reaction of rat antibody with antigen planted in either the GBM (especially the lamina rara interna) or in the subepithelial space (SE). Non-nephritogenic amounts of noncomplement-fixing sheep anti-GBM or anti-tubular brushborder antibody were injected into separate groups of rats to plant sheep IgG in the GBM and SE, respectively. Kidneys containing sheep IgG were then transplanted into naive recipients that were passively immunized with rat anti-sheep IgG. There was marked proteinuria after 2 days (antigen in GBM: 226 ± 50.7; antigen in SE: 69 ± 50.7 mg/24 hr) that was abrogated by prior depletion of complement in both groups (antigen in GBM: 10.2 ± 1.7; antigen in SE: 14.3 ± 8.7 mg/24 hr). When antigen was planted in SE, inflammatory-cell depletion with either anti-neutrophil (PMN) serum or lethal irradiation had no effect on proteinuria. In contrast, anti-PMN abolished proteinuria (12.0 ± 5.6 mg/24 hr) and irradiation reduced it by 60% when antigen was in GBM. Glomeruli of kidneys with antigen in GBM were significantly larger and more hypercellular than those with antigen in SE after transplantation into immunized recipients. Endothelial cell injury and adherence of inflammatory cells to denuded GBM were prominent in the former (antigen in GBM), while glomeruli with antigen in SE showed only subepithelial deposits, adjacent slit-diaphragm displacement, and epithelial cell foot-process effacement. Thus, the reaction of antigen and antibody in glomeruli produced complement-mediated injury which was cell-independent when complex formation occurred on the outer aspect of the GBM but was cell-dependent when the same reagents reacted more proximally to the circulation. We therefore conclude that antigen distribution can critically influence the mediation and morphologic expression of immune glomerular injury and may, in part, account for variations in the clinical and histological manifestations of antibody-induced glomerular disease in humans.Influence de la distribution antigénique sur la médiation des lésions glomérulaires immunologiques. Afin de déterminer si le site de la réaction immune pourrait influencer la médiation et l'expression morphologique des lésions glomérulaires lors d'une néphrite expérimentale anti-membrane basale glomérulaire (anti-GBM) et d'une néphropathie extra-membraneuse, nous avons étudié les événements qui suivaient la réaction in situ d'anticorps de rat avec un antigène fixé soit dans la GBM (surtout dans la lamina rara interna), soit dans l'espace sous-épithélial (SE). Des quantités non nephritogènes d'anticorps anti-GBM, ou anti-bordure en brosse tubulaire de mouton ne fixant pas le complément ont été injectées à différents groupes de rats pour fixer de l'IgG de mouton dans la GBM et le SE, respectivement. Les reins contenant l'IgG de mouton étaient alors transplantés à des receveurs vierges passivement immunisés avec de l'IgG de rat antimouton. Il existait une protéinurie marquée après deux jours (antigène dans la GBM: 226 ± 50,7; antigène dans SE: 69 ± 50,7 mg/24 hrs) qui à été abrogé par une déplétion du complement dans les deux groupes (antigène dans la GBM: 10,2 ± 1,7; antigène dans SE: 14,3 ± 8,7 mg/24 hr). Lorsque l'antigène était fixé dans SE, une déplétion en cellules inflammatoires par du sérum anti-neutrophile (PMN) ou une irradiation léthale n'avaient pas d'effet sur la protéinurie. A l'opposé, anti-PMN supprimait la protéinurie (12,0 ± 5,6 mg/24 hr) et l'irradiation la réduisait de 60% lorsque l'antigène était dans la GBM. Les glomérules de reins ayant l'antigène dans la GBM étaient significativement plus gros et plus hyper-cellulaires que ceux ayant l'antigène dans SE après transplantation chez des receveurs immunisés. Les lésions cellulaires endothéliales et l'adhérence des cellules inflammatoires à des GBM nues étaient prédominantes chez les premiers (antigène dans la GBM) alors que les glomérules ayant l'antigène dans SE présentaient uniquement des dépôts sous-épithéliaux, un déplacement du slit-diaphragme adjacent et un effacement des pédicelles des cellules épithéliales. Ainsi, la réaction d'un antigène et d'un anticorps dans des glomérules a produit des lésions à médiation complémentaire indépentantes des cellules lorsque la formation de complexes survenait dans la partie extérieure de la GBM, mais dépendantes des cellules lorsque les mêmes réactifs interagissaient de façon plus proximale dans la circulation. Nous concluons donc que la distribution antigénique peut influencer de manière critique la médiation et l'expression morphologique des lésions glomérulaires immunes et qu'elle peut, en partie, rendre compte de variations dans les manifestations cliniques et histologiques de glomérulopathies à médiation par anticorps chez l'homme
Identification, validation and clinical implementation of cancer biomarkers: Translational strategies of the EORTC PathoBiology Group
AbstractThe increasing demand for personalized cancer therapy requires a strong, intense, and continuous collaboration between pre-clinical and clinical investigators. As a part of the EORTC Translational Research Divison, the EORTC PathoBiology Group (EORTC PBG), focuses on discovery and validation of cancer biomarkers, providing both scientific evidence as well as quality assurance. The clinically relevant target-identification and validation studies carried out in the last decades within the EORTC PBG represent a paradigm for EORTC studies in which laboratory investigations on human biologic material are used to support the development of drugs directed to defined target molecules. The experience acquired within the EORTC PBG with respect to standardization of cancer biomarker test kits and reagents, quality assessment/assurance of cancer biomarker determinations, development of standard operating procedures for assessment of these markers as well as instruction of methodologies and teaching of ethical issues represent a valuable contribution of the EORTC PBG to the onco-translational strategies of the EORTC
Kaposi’s Sarcoma-Associated Herpesvirus Increases PD-L1 and Proinflammatory Cytokine Expression in Human Monocytes
ABSTRACT Kaposi’s sarcoma-associated herpesvirus (KSHV) is associated with the human malignancy Kaposi’s sarcoma and the lymphoproliferative disorders primary effusion lymphoma and multicentric Castleman’s disease. KSHV establishes lytic infection of monocytes in vivo , which may represent an important cellular reservoir during KS disease progression. KS tumors consist of latently infected endothelial cells; however, lytic phase gene products are important for KS onset. Early KS lesion progression is driven by proinflammatory cytokines supplied by immune cell infiltrates including T cells and monocytes. KSHV-infected monocytes may supply the lytic viral products and the inflammatory milieu conducive to KS tumor progression. To establish successful infection, KSHV extensively modulates the host immune system. KSHV antigens activate both innate and adaptive immune responses including KSHV-specific T cells, but lifelong infection is still established. Programmed death ligand 1 (PD-L1) is a prosurvival cell surface protein that suppresses T-cell-mediated killing. PD-L1 is variably present on various tumor cells and is a targetable marker for cancer treatment. We show that KSHV infection of human monocytes increases PD-L1 expression and transcription in a dose-dependent manner. We also saw evidence of lytic gene expression in the KSHV-infected monocytes. Intact KSHV is needed for full PD-L1 response in human monocytes. KSHV induces a general proinflammatory cytokine milieu including interleukins 1α, 1β, and 6, which have been implicated in early KS lesion progression. KSHV-mediated PD-L1 increase may represent a novel mechanism of KSHV-mediated immune modulation to allow for virus survival and eventually malignant progression. IMPORTANCE KSHV is the etiologic agent of Kaposi’s sarcoma and the lymphoproliferative disorders primary effusion lymphoma and multicentric Castleman’s disease. Programmed death ligand 1 (PD-L1) is an immunosuppressive cell surface marker that inhibits T cell activation. We report that KSHV infection of primary human monocytes upregulates PD-L1 transcription and protein expression. Analysis of the cytokine and chemokine milieu following KSHV infection of monocytes revealed that KSHV induces interleukins 1α, 1β, and 6, all of which have been implicated in KS development. Our work has identified another potential immune evasion strategy for KSHV and a potential target for immunotherapy of KSHV-derived disease
Modulation of the cGAS-STING DNA sensing pathway by gammaherpesviruses
Kaposi’s sarcoma-associated herpesvirus (KSHV) is a DNA virus that is linked to several human malignancies. The cGMP-AMP synthase (cGAS) and stimulator of interferon genes (STING) pathway is able to detect KSHV during primary infection and regulates the reactivation of KSHV from latency. We screened KSHV proteins for their ability to inhibit this pathway and block IFN-β activation. One KSHV protein, vIRF1, inhibited this pathway by preventing STING from interacting with TBK1 and inhibiting STING’s phosphorylation and concomitant activation. Moreover, depletion of vIRF1 in the context of KSHV infection prevented efficient viral reactivation and replication, and increased the host IFN response to KSHV. Collectively, our results demonstrate that the modulation of this pathway is important for viral transmission and the lifelong persistence of gammaherpesviruses in the human population
The genomes of two key bumblebee species with primitive eusocial organization
Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation
Dramatic Rise in Plasma Viremia after CD8+ T Cell Depletion in Simian Immunodeficiency Virus–infected Macaques
To determine the role of CD8+ T cells in controlling simian immunodeficiency virus (SIV) replication in vivo, we examined the effect of depleting this cell population using an anti-CD8 monoclonal antibody, OKT8F. There was on average a 99.9% reduction of CD8 cells in peripheral blood in six infected Macaca mulatta treated with OKT8F. The apparent CD8 depletion started 1 h after antibody administration, and low CD8 levels were maintained until day 8. An increase in plasma viremia of one to three orders of magnitude was observed in five of the six macaques. The injection of a control antibody to an infected macaque did not induce a sustained viral load increase, nor did it significantly reduce the number of CD8+ T cells. These results demonstrate that CD8 cells play a crucial role in suppressing SIV replication in vivo
Uncovering Blind Spots in Urban Carbon Management: The Role of Consumption-Based Carbon Accounting in Bristol, UK
The rapid urbanisation of the twentieth century, along with the spread of high-consumption urban lifestyles, has led to cities becoming the dominant drivers of global anthropogenic greenhouse gas emissions. Reducing these impacts is crucial, but production-based frameworks of carbon measurement and mitigation—which encompass only a limited part of cities’ carbon footprints—are much more developed and widely applied than consumption-based approaches that consider the embedded carbon effectively imported into a city. Frequently, therefore, cities are left blind to the importance of their wider consumption-related climate impacts, while at the same time left lacking effective tools to reduce them. To explore the relevance of these issues, we implement methodologies for assessing production- and consumption-based emissions at the city-level and estimate the associated emissions trajectories for Bristol, a major UK city, from 2000 to 2035. We develop mitigation scenarios targeted at reducing the former, considering potential energy, carbon and financial savings in each case. We then compare these mitigation potentials with local government ambitions and Bristol’s consumption-based emissions trajectory. Our results suggest that the city’s consumption-based emissions are three times the production-based emissions, largely due to the impacts of imported food and drink. We find that low-carbon investments of circa £3 billion could reduce production-based emissions by 25% in 2035. However, we also find that this represents <10% of Bristol’s forecast consumption-based emissions for 2035 and is approximately equal to the mitigation achievable by eliminating the city’s current levels of food waste. Such observations suggest that incorporating consumption-based emission statistics into cities’ accounting and decision-making processes could uncover largely unrecognised opportunities for mitigation that are likely to be essential for achieving deep decarbonisation
- …