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排序方式: 共有496条查询结果,搜索用时 109 毫秒
1.
Bharat Joshi Michele Bastiani Scott S. Strugnell Cecile Boscher Robert G. Parton Ivan R. Nabi 《The Journal of cell biology》2013,200(5):681-692
Maintenance of epithelial cell adhesion is crucial for epidermal morphogenesis and homeostasis and relies predominantly on the interaction of keratins with desmosomes. Although the importance of desmosomes to epidermal coherence and keratin organization is well established, the significance of keratins in desmosome organization has not been fully resolved. Here, we report that keratinocytes lacking all keratins show elevated, PKC-α–mediated desmoplakin phosphorylation and subsequent destabilization of desmosomes. We find that PKC-α activity is regulated by Rack1–keratin interaction. Without keratins, desmosomes assemble but are endocytosed at accelerated rates, rendering epithelial sheets highly susceptible to mechanical stress. Re-expression of the keratin pair K5/14, inhibition of PKC-α activity, or blocking of endocytosis reconstituted both desmosome localization at the plasma membrane and epithelial adhesion. Our findings identify a hitherto unknown mechanism by which keratins control intercellular adhesion, with potential implications for tumor invasion and keratinopathies, settings in which diminished cell adhesion facilitates tissue fragility and neoplastic growth. 相似文献
2.
Muhammad Furqan Bari Martin O. Weickert Kavitha Sivakumar Sean G. James David R. J. Snead Bee Kang Tan Harpal Singh Randeva Claire Cecile Bastie Manu Vatish 《PloS one》2014,9(7)
Recently soluble CD163 (sCD163), a cleaved form of the macrophage receptor CD163, was identified as a macrophage-specific risk-predictor for developing Type 2 Diabetes. Here, we investigate circulating levels of sCD163 in gestational diabetes mellitus (GDM). Furthermore, given the role of the placenta in the pathogenesis of GDM, we assessed placental contribution to sCD163 secretion. Paired maternal (venous) and umbilical vein blood samples from GDM (n = 18) and Body Mass Index (BMI) matched control women (n = 20) delivered by caesarean section at 39–40 week gestation were assessed for circulating levels of sCD163, Tumour necrosis factor alpha (TNF-α) and Interleukin 6 (IL-6). Media from explant culture of maternal subcutaneous fat and corresponding placental tissues were assayed for these same molecules. CD163 positive cell numbers were determined in placental and adipose tissues of GDM and control women. We found significantly elevated circulating sCD163 levels in GDM mothers (688.4±46.9 ng/ml vs. 505.6±38.6 ng/ml) and their offspring (418.2±26.6 ng/ml vs. 336.3±24.4 ng/ml [p<0.05 for both]) as compared to controls, together with elevated circulating TNF-α and IL-6 levels. Moreover, both GDM placentae (268.1±10.8 ng/ml/mg vs. 187.6±20.6 ng/ml/mg) and adipose explants (41.1±2.7 ng/ml/mg vs. 26.6±2.4 ng/ml/mg) released significantly more sCD163 than controls. Lastly, significantly more CD163 positive cells were observed in GDM placentae (25.7±1.1 vs. 22.1±1.2) and adipose tissue (19.1±1.1 vs 12.7±0.9) compared to controls. We describe elevated sCD163 levels in GDM and identify human placenta as a novel source of sCD163 suggesting that placental tissues might contribute to the increased levels of circulating sCD163 in GDM pregnancies. 相似文献
3.
Marco Thomann Tilman Schlothauer Tetyana Dashivets Sebastian Malik Cecile Avenal Patrick Bulau Petra Rüger Dietmar Reusch 《PloS one》2015,10(8)
The importance and effect of Fc glycosylation of monoclonal antibodies with regard to biological activity is widely discussed and has been investigated in numerous studies. Fc glycosylation of monoclonal antibodies from current production systems is subject to batch-to-batch variability. If there are glycosylation changes between different batches, these changes are observed not only for one but multiple glycan species. Therefore, studying the effect of distinct Fc glycan species such as galactosylated and sialylated structures is challenging due to the lack of well-defined differences in glycan patterns of samples used. In this study, the influence of IgG1 Fc galactosylation and sialylation on its effector functions has been investigated using five different samples which were produced from one single drug substance batch by in vitro glycoengineering. This sample set comprises preparations with minimal and maximal galactosylation and different levels of sialylation of fully galactosylated Fc glycans. Among others, Roche developed the glycosyltransferase enzyme sialyltransferase which was used for the in vitro glycoengineering activities at medium scale. A variety of analytical assays, including Surface Plasmon Resonance and recently developed FcγR affinity chromatography, as well as an optimized cell-based ADCC assay were applied to investigate the effect of Fc galactosylation and sialylation on the in vitro FcγRI, IIa, and IIIa receptor binding and ADCC activity of IgG1. The results of our studies do not show an impact, neither positive nor negative, of sialic acid- containing Fc glycans of IgG1 on ADCC activity, FcγRI, and RIIIa receptors, but a slightly improved binding to FcγRIIa. Furthermore, we demonstrate a galactosylation-induced positive impact on the binding activity of the IgG1 to FcγRIIa and FcγRIIIa receptors and ADCC activity. 相似文献
4.
Boris Pastorino Cecile Baronti Ernest A. Gould Remi N. Charrel Xavier de Lamballerie 《PloS one》2015,10(4)
As a partner of the European Virus Archive (EVA) FP7 project, our laboratory maintains a large collection of freeze-dried viruses. The distribution of these viruses to academic researchers, public health organizations and industry is one major aim of the EVA consortium. It is known that lyophilization requires appropriate stabilizers to prevent inactivation of the virus. However, few studies have investigated the influence of different stabilizers and lyophilization protocols on the thermostability of different viruses. In order to identify optimal lyophilization conditions that will deliver maximum retention of viral infectivity titre, different stabilizer formulations containing trehalose, sorbitol, sucrose or foetal bovine serum were evaluated for their efficacy in stabilizing a representative panel of freeze dried viruses at different storage temperatures (-20°C, +4°C and +20°C) for one week, the two latter mimicking suboptimal shipping conditions. The Tissue Culture Infectious Dose 50% (TCID50) assay was used to compare the titres of infectious virus. The results obtained using four relevant and model viruses (enveloped/non enveloped RNA/DNA viruses) still serve to improve the freeze drying conditions needed for the development and the distribution of a large virus collection. 相似文献
5.
Effects of climate change on the delivery of soil‐mediated ecosystem services within the primary sector in temperate ecosystems: a review and New Zealand case study 下载免费PDF全文
Kate H. Orwin Bryan A. Stevenson Simeon J. Smaill Miko U. F. Kirschbaum Ian A. Dickie Brent E. Clothier Loretta G. Garrett Tony J. van der Weerden Michael H. Beare Denis Curtin Cecile A. M. de Klein Michael B. Dodd Roberta Gentile Carolyn Hedley Brett Mullan Mark Shepherd Steven A. Wakelin Nigel Bell Saman Bowatte Murray R. Davis Estelle Dominati Maureen O'Callaghan Roger L. Parfitt Steve M. Thomas 《Global Change Biology》2015,21(8):2844-2860
Future human well‐being under climate change depends on the ongoing delivery of food, fibre and wood from the land‐based primary sector. The ability to deliver these provisioning services depends on soil‐based ecosystem services (e.g. carbon, nutrient and water cycling and storage), yet we lack an in‐depth understanding of the likely response of soil‐based ecosystem services to climate change. We review the current knowledge on this topic for temperate ecosystems, focusing on mechanisms that are likely to underpin differences in climate change responses between four primary sector systems: cropping, intensive grazing, extensive grazing and plantation forestry. We then illustrate how our findings can be applied to assess service delivery under climate change in a specific region, using New Zealand as an example system. Differences in the climate change responses of carbon and nutrient‐related services between systems will largely be driven by whether they are reliant on externally added or internally cycled nutrients, the extent to which plant communities could influence responses, and variation in vulnerability to erosion. The ability of soils to regulate water under climate change will mostly be driven by changes in rainfall, but can be influenced by different primary sector systems' vulnerability to soil water repellency and differences in evapotranspiration rates. These changes in regulating services resulted in different potentials for increased biomass production across systems, with intensively managed systems being the most likely to benefit from climate change. Quantitative prediction of net effects of climate change on soil ecosystem services remains a challenge, in part due to knowledge gaps, but also due to the complex interactions between different aspects of climate change. Despite this challenge, it is critical to gain the information required to make such predictions as robust as possible given the fundamental role of soils in supporting human well‐being. 相似文献
6.
Cecile Lebon Gloria Villalpando RodriguezIkram El Zaoui Imene JaadaneFrancine Behar-Cohen Alicia Torriglia 《Analytical biochemistry》2015
Apoptosis is an essential cellular mechanism involved in many processes such as embryogenesis, metamorphosis, and tissue homeostasis. DNA fragmentation is one of the key markers of this form of cell death. DNA fragmentation is executed by endogenous endonucleases such as caspase-activated DNase (CAD) in caspase-dependent apoptosis. The TUNEL (TdT-mediated dUTP–biotin nick end labeling) technique is the most widely used method to identify apoptotic cells in a tissue or culture and to assess drug toxicity. It is based on the detection of 3′-OH termini that are labeled with dUTP by the terminal deoxynucleotidyl transferase. Although the test is very reliable and sensitive in caspase-dependent apoptosis, it is completely useless when cell death is mediated by pathways involving DNA degradation that generates 3′-P ends as in the LEI/L-DNase II pathway. Here, we propose a modification in the TUNEL protocol consisting of a dephosphorylation step prior to the TUNEL labeling. This allows the detection of both types of DNA breaks induced during apoptosis caspase-dependent and independent pathways, avoiding underestimating the cell death induced by the treatment of interest. 相似文献
7.
8.
Cecile Duterme Jeannine Mertens-Strijthagen Markku Tammi Bruno Flamion 《The Journal of biological chemistry》2009,284(48):33495-33508
It has long been predicted that the members of the hyaluronidase enzyme family have important non-enzymatic functions. However, their nature remains a mystery. The metabolism of hyaluronan (HA), their major enzymatic substrate, is also enigmatic. To examine the function of Hyal2, a glycosylphosphatidylinositol-anchored hyaluronidase with intrinsically weak enzymatic activity, we have compared stably transfected rat fibroblastic BB16 cell lines with various levels of expression of Hyal2. These cell lines continue to express exclusively the standard form (CD44s) of the main HA receptor, CD44. Hyal2, CD44, and one of its main intracellular partners, ezrin-radixin-moesin (ERM), were found to co-immunoprecipitate. Functionally, Hyal2 overexpression was linked to loss of the glycocalyx, the HA-rich pericellular coat. This effect could be mimicked by exposure of BB16 cells either to Streptomyces hyaluronidase, to HA synthesis inhibitors, or to HA oligosaccharides. This led to shedding of CD44, separation of CD44 from ERM, reduction in baseline level of ERM activation, and markedly decreased cell motility (50% reduction in a wound healing assay). The effects of Hyal2 on the pericellular coat and on CD44-ERM interactions were inhibited by treatment with the Na+/H+ exchanger-1 inhibitor ethyl-N-isopropylamiloride. We surmise that Hyal2, through direct interactions with CD44 and possibly some pericellular hyaluronidase activity requiring acidic foci, suppresses the formation or the stability of the glycocalyx, modulates ERM-related cytoskeletal interactions, and diminishes cell motility. These effects may be relevant to the purported in vivo tumor-suppressive activity of Hyal2. 相似文献
9.
Jean-Jacques Legrand Cecile Fisch Pierre-Olivier Guillaumat Jean-Marc Pavard Mahmoud Attia Stephane De Jouffrey 《Biomarkers》2013,18(1):63-77
The ovariectomized old cynomolgus monkey is a recognized model of human osteoporosis, and the same species can be used for the assessment of the efficacy and potential toxicity of agents intended to prevent or treat osteoporosis. Several assays have been developed that can measure the same biochemical markers of bone turnover as are used in human patients for the diagnosis and treatment follow-up of bone-related diseases, including osteoporosis. The aim of the present study was to describe the results obtained with these assays in normal control monkeys, their variations with age and sex, and their sensitivity in monitoring the bone turnover induced by ovariectomy in old skeletally mature cynomolgus monkeys. Seven old cynomolgus monkeys were bilaterally ovariectomized and 13 age-matched monkeys were sham-operated. Bone mineral density and biochemical markers were measured before and at regular intervals after surgery for up to 20 months. Total alkaline phosphatase (total ALP), bone-specific alkaline phosphatase isoenzyme (bone ALP) and osteocalcin (OC) were highly correlated to the decrease in bone mineral density (BMD) induced by ovariectomy. Deoxypyridinoline (DPD) measured by enzyme-linked immunoassay was insensitive to the bone resorption induced by ovariectomy, but cross-linked N-telopeptide (NTX-I) was higher in ovariectomized monkeys than in control monkeys. These results demonstrate that reliable biochemical parameters are available to adequately monitor and provide insight into osteoclastic bone resorption and osteoblastic bone formation, the two components of bone turnover in this animal model, and can thus be used to assess the efficacy and toxicity of potential therapeutic agents. 相似文献
10.
Vincent Daien Isabelle Carriere Ryo Kawasaki Jean-Paul Cristol Max Villain Pierre Fesler Karen Ritchie Cecile Delcourt 《PloS one》2013,8(7)