Anti-idiotype RNAs that mimic the leucine-rich nuclear export signal and specifically bind to CRM1/exportin 1

AbstractBackground: Anti-idiotype approaches are based on the assumption that an antibody recognising a ligand can be structurally related to the receptor. Recently we have generated anti-idiotype RNA aptamers designed to mimic the human immunodeficiency virus-1 (HIV-1) Rev nuclear export signal (NES). Nuclear injection of either NES–peptide conjugates or aptamer causes the inhibition of Rev-mediated export. This implied that NES mimics and export substrate might compete for binding to the NES receptor. The mechanism of inhibition, however, is unknown.Results: The interaction between the export aptamer and CRM1 was characterised in vitro. The aptamer binds specifically to CRM1 and this interaction is sensitive to competition by Rev NES–peptide conjugates. The recognition domain of CRM1 has been mapped and includes residues found previously to affect binding of leptomycin B, a fungicide interfering with nuclear export.Conclusions: Inhibition of Rev-mediated export in vivo by export aptamers appears to result from the binding of the aptamers to the NES-recognition domain of CRM1. This observation demonstrates that anti-idiotype RNA can mimic faithfully structural and functional properties of a protein and can be used to map ligand-binding domains of receptors

MPI Phantom Study with A High-Performing Multicore Tracer Made by Coprecipitation

Magnetic particle imaging (MPI) is a new imaging technique that detects the spatial distribution of magnetic nanoparticles (MNP) with the option of high temporal resolution. MPI relies on particular MNP as tracers with tailored characteristics for improvement of sensitivity and image resolution. For this reason, we developed optimized multicore particles (MCP 3) made by coprecipitation via synthesis of green rust and subsequent oxidation to iron oxide cores consisting of a magnetite/maghemite mixed phase. MCP 3 shows high saturation magnetization close to that of bulk maghemite and provides excellent magnetic particle spectroscopy properties which are superior to Resovist® and any other up to now published MPI tracers made by coprecipitation. To evaluate the MPI characteristics of MCP 3 two kinds of tube phantoms were prepared and investigated to assess sensitivity, spatial resolution, artifact severity, and selectivity. Resovist® was used as standard of comparison. For image reconstruction, the regularization factor was optimized, and the resulting images were investigated in terms of quantifying of volumes and iron content. Our results demonstrate the superiority of MCP 3 over Resovist® for all investigated MPI characteristics and suggest that MCP 3 is promising for future experimental in vivo studies

Uraemic extracellular vesicles augment osteogenic transdifferentiation of vascular smooth muscle cells via enhanced AKT signalling and PiT‐1 expression

Extracellular vesicles (EV) function as messengers between endothelial cells (EC) and vascular smooth muscle cells (VSMC). Since chronic kidney disease (CKD) increases the risk for vascular calcifications, we investigated whether EV derived from uraemic milieu-stimulated EC and derived from uraemic rats impact the osteogenic transdifferentiation/calcification of VSMC. For that purpose, human EC were treated with urea and indoxyl sulphate or left untreated. Experimental uraemia in rats was induced by adenine feeding. 'Uraemic' and control EV (EVUR; EVCTRL) were isolated from supernatants and plasma by using an exosome isolation reagent. Rat VSMC were treated with a pro-calcifying medium (CM) with or without EV supplementation. Gene expressions, miRNA contents and protein expressions were determined by qPCR and Western blots, respectively. Calcifications were determined by colorimetric assays. Delivery of miRNA inhibitors/mimics to EV and siRNA to VSMC was achieved via transfection. EVCTRL and EVUR differed in size and miRNA contents. Contrary to EVCTRL, EC- and plasma-derived EVUR significantly increased the pro-calcifying effects of CM, including altered gene expressions of osterix, runx2, osteocalcin and SM22 alpha. Further, EVUR enhanced the protein expression of the phosphate transporter PiT-1 in VSMC and induced a phosphorylation of AKT and ERK. Knock down of PiT-1 and individual inhibition of AKT and ERK signalling in VSMC blocked the pro-calcifying effects of EVUR. Similar effects were achieved by inhibition of miR-221/-222 and mimicking of miR-143/-145 in EVUR. In conclusion, EVUR might represent an additional puzzle piece of the complex pathophysiology of vascular calcifications in CKD

Astrocyte mediated modulation of blood-brain barrier permeability does not correlate with a loss of tight junction proteins from the cellular contacts

In the central nervous system (CNS) complex endothelial tight junctions (TJs) form a restrictive paracellular diffusion barrier, the blood-brain barrier (BBB). Pathogenic changes within the CNS are frequently accompanied by the loss of BBB properties, resulting in brain edema. In order to investigate whether BBB leakiness can be monitored by a loss of TJ proteins from cellular borders, we used an in vitro BBB model where brain endothelial cells in co-culture with astrocytes form a tight permeability barrier for 3H-inulin and 14C-sucrose. Removal of astrocytes from the co-culture resulted in an increased permeability to small tracers across the brain endothelial cell monolayer and an opening of the TJs to horseradish peroxidase as detected by electron microscopy. Strikingly, opening of the endothelial TJs was not accompanied by any visible change in the molecular composition of endothelial TJs as junctional localization of the TJ-associated proteins claudin-3, claudin-5, occludin, ZO-1 or ZO-2 or the adherens junction-associated proteins β-catenin or p120cas did not change. Thus, opening of BBB TJs is not readily accompanied by the complete loss of the junctional localization of TJ protein

Intercomparison of Gridded Precipitation Datasets over a Sub-Region of the Central Himalaya and the Southwestern Tibetan Plateau

Precipitation is a central quantity of hydrometeorological research and applications. Especially in complex terrain, such as in High Mountain Asia (HMA), surface precipitation observations are scarce. Gridded precipitation products are one way to overcome the limitations of ground truth observations. They can provide datasets continuous in both space and time. However, there are many products available, which use various methods for data generation and lead to different precipitation values. In our study we compare nine different gridded precipitation products from different origins (ERA5, ERA5-Land, ERA-interim, HAR v2 10 km, HAR v2 2 km, JRA-55, MERRA-2, GPCC and PRETIP) over a subregion of the Central Himalaya and the Southwest Tibetan Plateau, from May to September 2017. Total spatially averaged precipitation over the study period ranged from 411 mm (GPCC) to 781 mm (ERA-Interim) with a mean value of 623 mm and a standard deviation of 132 mm. We found that the gridded products and the few observations, with few exceptions, are consistent among each other regarding precipitation variability and rough amount within the study area. It became obvious that higher grid resolution can resolve extreme precipitation much better, leading to overall lower mean precipitation spatially, but higher extreme precipitation events. We also found that generally high terrain complexity leads to larger differences in the amount of precipitation between products. Due to the considerable differences between products in space and time, we suggest carefully selecting the product used as input for any research application based on the type of application and specific research question. While coarse products such as ERA-Interim or ERA5 that cover long periods but have coarse grid resolution have previously shown to be able to capture long-term trends and help with identifying climate change features, this study suggests that more regional applications, such as glacier mass-balance modeling, require higher spatial resolution, as is reproduced, for example, in HAR v2 10 km.Peer Reviewe

COMTVal158Met Genotype Affects Complex Emotion Recognition in Healthy Men and Women

The catechol-o-methyltransferase (COMT) gene has repeatedly been shown to change amygdala activity and amygdala-prefrontal connectivity during face processing. Although the COMT gene appears to induce a negativity bias during the neural processing of faces, it is currently unclear whether a similar negativity bias emerges during the behavioral processing of faces. To address this issue, we investigated differences in complex emotion recognition between participants (n = 181) that had been a priori genotyped for functional polymorphisms of the COMT (Val158Met) and serotonin transporter (5-HTTLPR) gene. We were, thus, able to analyze differences in face processing on basis of participants’ COMT genotype while controlling for participants’ 5-HTTLPR genotype. Variations of participants’ COMT but not 5-HTTLPR genotype accounted for differences in participants’ emotion recognition performance: Met/Met carriers and Met/Val carriers were more accurate in the recognition of negative, but not neutral or positive, expressions than Val/Val carriers. We, therefore, revealed a similar negativity bias during the behavioral processing of faces that has already been demonstrated during the neural processing of faces, indicating that genotype-dependent changes in catecholamine metabolism may affect face processing on the behavioral and neural level

LRAD – A Radiometer for the Lunar South Ppole Hopper µNOVA

The Lunar Prospector discovery of areas of neutron suppression and the subsequent interpretation of hydrogen enrichment near the lunar poles brought the possibility of volatile resources sequestered at the poles to the forefront of the lunar science community. Subsequently the LCROSS experiment showed that water ice is present within at least one permanently shadowed region (PSR) near the south pole and that it can be stable over geological timescales inside permanently shadowed regions (PSRs). Analysis of UV observations gathered by the Lunar Reconnaissance Orbiter Diviner instrument are consistent with the presence of surface frost in some PSRs with temperatures below 110 K. Further, the depth-to-diameter ratios of simple craters as determined from Lunar Orbiter Laser Altimeter (LOLA) altimetric measurements indicate that deposits of water ice in these cold traps may be up to 50 m thick. Moreover, water ice may be present in small PSRs at scales down to, and below 10 meters [5]. Such small-scale cold traps could significantly increase water inventory estimates and eventually simplify extraction

Immune stimulation mediated by autoantigen binding sites within small nuclear RNAs involves Toll-like receptors 7 and 8

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies to certain cellular macromolecules, such as the small nuclear ribonucleoprotein particles (snRNPs), which had been considered to be passive targets of the autoimmune response. SLE is also characterized by the increased expression of type I interferon (IFN), which appears to be associated with the development and severity of disease. Here, we show that specific, highly conserved RNA sequences within snRNPs can stimulate Toll-like receptors (TLRs) 7 and 8 as well as activate innate immune cells, such as plasmacytoid dendritic cells (pDCs), which respond by secreting high levels of type I IFN. SLE patient sera containing autoantibodies to snRNPs form immune complexes that are taken up through the Fc receptor γRII and efficiently stimulate pDCs to secrete type I IFNs. These results demonstrate that a prototype autoantigen, the snRNP, can directly stimulate innate immunity and suggest that autoantibodies against snRNP may initiate SLE by stimulating TLR7/8

In-Situ Radiometric Investigation of Phobos using the MMX Rover’s miniRAD Instrument.

The JAXA MMX sample return mission to the martian moons will deliver a rover to the surface of Phobos that will investigate the landing area using its navigation cameras (NavCams), its regolith facing cameras (WheelCams), its Raman spectrometer (RAX), as well as its mid infrared radiometer (miniRAD). The distance that can be travelled by the Rover depends on the yet unknown terrain properties, but is estimated to range from a few meters to hundreds of meters. The rover and its instruments will operate on the surface of Phobos for at least 100 days

LRAD – The Radiometer for the Lunar South Pole Hopper μNOVA.

Permanently shadowed regions (PSRs) are present at the Lunar poles. The surface temperature inside a PSR can remain below 110K, low enough fow stable water ice to exist in vacuum. The presence of ater ice at the Lunar Poles has been indicated by remote sensing bservations, in particular by the Lunar Prospector, LCROSS, and LRO missions. As part of the NASA Commerical Lunar Payload Service program, the Nova-C lander will be build and operated by the US-based company Intuitive Machines. Nova-C will land near the Lunar south pole for in-situ inverstigations of potential volatiles in the regolith. Nova-C will carry the S.P. Hopper to the Moon which will in a sequence of short flights land within a PSR inside Marston crater (informal name) close to a potential landing site for the Artemis Astronauts [7]. The Hopper will map the lunar surface with two cameras and a themal infrared radiometer (LRAD)