The Role of Interleukin-1-Receptor-Antagonist in Bladder Cancer Cell Migration and Invasion

Background: The interleukin-1-receptor antagonist IL1RA (encoded by the IL1RN gene) is a potent competitive antagonist to interleukin-1 (IL1) and thereby is mainly involved in the regulation of inflammation. Previous data indicated a role of IL1RA in muscle-invasive urothelial carcinoma of the bladder (UCB) as well as an IL1-dependent decrease in tissue barrier function, potentially contributing to cancer cell invasion. Objective: Based on these observations, here we investigated the potential roles of IL1RA, IL1A, and IL1B in bladder cancer cell invasion in vitro. Methods: Cell culture, real-time impedance sensing, invasion assays (Boyden chamber, pig bladder model), qPCR, Western blot, ELISA, gene overexpression. Results: We observed a loss of IL1RA expression in invasive, high-grade bladder cancer cell lines T24, UMUC-3, and HT1197 while IL1RA expression was readily detectable in the immortalized UROtsa cells, the non-invasive bladder cancer cell line RT4, and in benign patient urothelium. Thus, we modified the invasive human bladder cancer cell line T24 to ectopically express IL1RA, and measured changes in cell migration/invasion using the xCELLigence Real-Time-Cell-Analysis (RTCA) system and the Boyden chamber assay. The real-time observation data showed a significant decrease of cell migration and invasion in T24 cells overexpressing IL1RA (T24-IL1RA), compared to cells harboring an empty vector (T24-EV). Concurrently, tumor cytokines, e.g., IL1B, attenuated the vascular endothelial barrier, which resulted in a reduction of the Cell Index (CI), an impedance-based dimensionless unit. This reduction could be reverted by the simultaneous incubation with IL1RA. Moreover, we used an ex vivo porcine organ culture system to evaluate cell invasion capacity and showed that T24-IL1RA cells showed significantly less invasive capacity compared to parental T24 cells or T24-EV. Conclusions: Taken together, our results indicate an inverse correlation between IL1RA expression and tumor cell invasive capacity and migration, suggesting that IL1RA plays a role in bladder carcinogenesis, while the exact mechanisms by which IL1RA influences tumor cells migration/invasion remain to be clarified in future studies. Furthermore, we confirmed that real-time impedance sensing and the porcine ex vivo organ culture methods are powerful tools to discover differences in cancer cell migration and invasion.     

Mutations in the nucleotide-binding domain of putative sterol importers Aus1 and Pdr11 selectively affect utilization of exogenous sterol species in yeast

Sterol uptake in the yeast Saccharomyces cerevisiae is mediated by two plasma membrane ATP-binding cassette transporters, Aus1 and Pdr11. Their expression is regulated by oxygen and is triggered by anaerobic growth conditions. Under these conditions, internal ergosterol synthesis is arrested and utilization of exogenous sterol is vital for yeast cells. Here, we demonstrate that Aus1 is the major importer of non–yeast sterols, mammalian cholesterol, and plant sterols under anaerobic conditions. In contrast, uptake of yeast native sterol, ergosterol, is relatively low. This uptake could not be enhanced by overexpression of either of the transporters. Interestingly, overexpression of the minor importer Pdr11 resulted in a substantial import of non–yeast sterols. We show that mutation of the conserved residue in one of the ABC characteristic motifs—the H-loop in Aus1 and Pdr11—lowered their ATPase activity. The residual activity was sufficient to import exogenous sterols and to preserve cell viability. Importantly, the reduction of sterol import was dramatic for mammalian cholesterol and plant sterols, whereas import of yeast ergosterol was decreased only slightly indicating substrate selectivity of the sterol utilization process.     

Polypropylene/polyethylene blends as models for high‐impact propylene‐ethylene copolymers,part 2: Relation between composition and mechanical performance

The relation between composition and mechanical performance of a series of binary polyolefin blends was studied in this article. A fractionation of these model compounds with temperature rising elution fractionation (TREF) was applied to study the possibility to fractionate industrially relevant heterophasic polyolefin systems. The separation quality according to molecular structures or chemical composition was found to be good for most of the systems, but especially the separation of ethylene‐propylene random copolymer and high density polyethylene by TREF turned out to be difficult if not impossible. An extensive mechanical characterisation including the determination of brittle‐to‐ductile transition curves showed significant effects of modifier type and amount. Toughness effects can be related primarily to the modulus differences between modifier and matrix. Compatibility and particle size only have a secondary influence, but must be considered for a detailed interpretation of the mechanics of the investigated systems. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Rheological and thermal behaviour of poly(N‐isopropylacrylamide)/alginate smart polymeric networks

Interpenetrating polymeric networks based on sodium alginate and poly(N‐isopropylacrylamide) (PNIPAAm) covalently crosslinked with N,N′‐methylenebisacrylamide have been investigated using rheology, thermogravimetry, differential scanning calorimetry, X‐ray diffraction measurements and scanning electron microscopy (SEM). An improved elastic response of the samples with a higher PNIPAAm content and increased amount of crosslinking agent was found. The temperature‐responsive behaviour of the hydrogel samples was evidenced by viscoelastic measurements performed at various temperatures. It is shown that the properties of these gels can be tuned according to composition, amount of crosslinking agent and temperature changes. X‐ray scattering analysis revealed that the hydrophobic groups are locally segregated even in the swollen state whilst cryo‐SEM showed the highly heterogeneous nature of the gels. Copyright © 2011 Society of Chemical Industry     

How does plant leaf senescence of grassland species influence decomposition kinetics and litter compounds dynamics?

The influence of litter quality on plant litter decomposition rates is a crucial aspect of the soils C cycle. In grassland ecosystems, leaf litter, which is not removed either by herbivores or by mowing, returns to soil after the senescence process (brown litter). In grassland managed by mowing, another significant proportion of litter returns to the soil before senescence through harvesting losses (green litter). We hypothesized that changes in leaf tissue quality due to the senescence process would lead to contrasting decomposition dynamics of brown litter compared to green litter. Our conceptual approach included the monitoring of decomposition of green (fresh leaves) and brown litter (dead leaves, still attached to the plant) of three different grassland species (Lolium perenne, Festuca arundinacea and Dactylis glomerata) during a 1 year field incubation. After 0, 2, 4, 20 and 44 weeks, we retrieved the litterbags and analysed the remaining material for carbon and nitrogen content and stable isotope composition. Additionally, we determined the lignin content and composition by CuO oxidation and the non-cellulosic neutral carbohydrate content and composition after TFA hydrolysis. As expected, green litter, being higher in N and soluble compounds, while showing a lower C:N ratio and lower lignin contents compared to brown litter, was degraded at a higher rate. Carbon decomposition kinetics suggests that both leaf litter types consist of two pools with contrasting turnover times. The size of the active pool was related to the initial content of soluble plant litter compounds and the size of the recalcitrant pool was related to the lignin to N ratio of initial plant material. More lignin was lost from green litter compared to brown litter. P-coumaryl-type lignin units were decomposed at a higher rate than vanillyl and syringyl units. Total non cellulosic polysaccharide content showed little changes for both litter types. In contrast, the ratios of hexoses/pentoses (C6/C5) and desoxy sugars/pentoses (desoxy/C5) increased during decomposition of green litter only. This is an indication for an increasing contribution of microbial derived compounds being consistant with the higher decomposition rate of this material. Our results showed that grassland management (grazing versus mowing) could influence soil carbon sequestration through different proportions of green and brown litter returned to soil.     

Innovative Strategy for MicroRNA Delivery in Human Mesenchymal Stem Cells via Magnetic Nanoparticles

Bone marrow derived human mesenchymal stem cells (hMSCs) show promising potential in regeneration of defective tissue. Recently, gene silencing strategies using microRNAs (miR) emerged with the aim to expand the therapeutic potential of hMSCs. However, researchers are still searching for effective miR delivery methods for clinical applications. Therefore, we aimed to develop a technique to efficiently deliver miR into hMSCs with the help of a magnetic non-viral vector based on cationic polymer polyethylenimine (PEI) bound to iron oxide magnetic nanoparticles (MNP). We tested different magnetic complex compositions and determined uptake efficiency and cytotoxicity by flow cytometry. Additionally, we monitored the release, processing and functionality of delivered miR-335 with confocal laser scanning microscopy, real-time PCR and live cell imaging, respectively. On this basis, we established parameters for construction of magnetic non-viral vectors with optimized uptake efficiency (~75%) and moderate cytotoxicity in hMSCs. Furthermore, we observed a better transfection performance of magnetic complexes compared to PEI complexes 72 h after transfection. We conclude that MNP-mediated transfection provides a long term effect beneficial for successful genetic modification of stem cells. Hence, our findings may become of great importance for future in vivo applications.     

The Influence of Interfacial Areas for Gas Absorption in the Presence of Solid Particles

The mass transfer is investigated for physical absorption of oxygen in water for varying interfacial areas as well as the influence of suspended glass beads and activated carbon. Under higher rotational speed, the volumetric mass transfer coefficient as well as the mass transfer coefficient values increase for all specific interfacial areas due to the changes in hydrodynamics. The configuration of the free gas‐liquid interface is of minor relevance. In the presence of glass beads, the mass transfer is reduced compared to physical adsorption, whereas an enhancement of the mass transfer can be observed in the presence of activated carbon. This indicates that the mobility of the gas‐liquid interface is the determining factor. The renewal of the fluid elements is increased by adsorption of surfactants on the surface of activated carbon, leading to an improved mass transport.     

Performance analysis of mixed ionic-electronic conducting cathodes in anode supported cells

The analysis of mixed ionic-electronic conducting (MIEC) cathodes with respect to operation temperature and time is essential for a target-oriented development of anode-supported solid oxide fuel cells (ASCs). This study tracks both issues by impedance spectroscopy on a high-performance cathode with the composition La_0.58Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF).A wide set of impedance spectra were sampled at 600, 750 and 900 °C over the entire operation time of 1000 h. The identification and quantification of the individual anodic and cathodic contributions to the polarization losses of an ASC were enabled by an appropriate equivalent circuit model. For this purpose, the impedance data sets were evaluated subsequently by (i) a DRT (distribution of relaxation times) analysis followed by (ii) a CNLS fit. The cathodic polarization resistance is attributed to the oxygen surface exchange and the bulk diffusion of oxygen ions and is described by a Gerischer element.The anodic polarization resistance is described by a Warburg element and two RQ elements according to physical origins. The thorough analysis of all data sets leads to the surprising outcome that the cathode degradation is most pronounced and moreover, increases with decreasing temperature. After 1000 h of operation, the cathode polarization resistance raised steeply from 0.012%/h at 900 °C over 0.28%/h at 750 °C to 1.49%/h at 600 °C. These latest findings will have far-reaching implications for the development of MIEC cathodes.