A Structural Basis for Cellular Uptake of GST-Fold Proteins

It has recently emerged that glutathione transferase enzymes (GSTs) and other structurally related molecules can be translocated from the external medium into many different cell types. In this study we aim to explore in detail, the structural features that govern cell translocation and by dissecting the human GST enzyme GSTM2-2 we quantatively demonstrate that the α-helical C-terminal domain (GST-C) is responsible for this property. Attempts to further examine the constituent helices within GST-C resulted in a reduction in cell translocation efficiency, indicating that the intrinsic GST-C domain structure is necessary for maximal cell translocation capacity. In particular, it was noted that the α-6 helix of GST-C plays a stabilising role in the fold of this domain. By destabilising the conformation of GST-C, an increase in cell translocation efficiency of up to ∼2-fold was observed. The structural stability profiles of these protein constructs have been investigated by circular dichroism and differential scanning fluorimetry measurements and found to impact upon their cell translocation efficiency. These experiments suggest that the globular, helical domain in the 'GST-fold' structural motif plays a role in influencing cellular uptake, and that changes that affect the conformational stability of GST-C can significantly influence cell translocation efficiency.This work was supported by Grant DP0558315 Australian Research Council (http://www.arc.gov.au/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Antidepressant-like effect of losartan involves TRKB transactivation from angiotensin receptor type 2 (AGTR2) and recruitment of FYN

The renin-angiotensin system (RAS) is associated with peripheral fluid homeostasis and cardiovascular function, but recent evidence also suggests a functional role in the brain. RAS regulates physiological and behavioral parameters related to the stress response, including depressive symptoms. Apparently, RAS can modulate levels of brain-derived neurotrophic factor (BDNF) and TRKB, which are important in the neurobiology of depression and antidepressant action. However, the interaction between the BDNF/TRKB system and RAS in depression has not been investigated before. Accordingly, in the forced swimming test, we observed an antidepressant-like effect of systemic losartan but not with captopril or enalapril treatment. Moreover, infusion of losartan into the ventral hippocampus (vHC) and prelimbic prefrontal cortex (PL) mimicked the consequences of systemically injected losartan, whereas K252a (a blocker of TRK) infused into these brain areas impaired such effect. PD123319, an antagonist of AT2 receptor (AGTR2), also prevented the systemic losartan effect when infused into PL but not into vHC. Cultured cortical cells of rat embryos revealed that angiotensin II (ANG2), possibly through AGTR2, increased the surface levels of TRKB and its coupling to FYN, a SRC family kinase. Higher Agtr2 levels in cortical cells were reduced after stimulation with glutamate, and only under this condition an interaction between losartan and ANG2 was achieved. TRKB/AGTR2 heterodimers were also observed, in MG87 cells GFP-tagged AGTR2 co-immunoprecipitated with TRKB. Therefore, the antidepressant-like effect of losartan is proposed to occur through a shift of ANG2 towards AGTR2, followed by coupling of TRK/FYN and putative TRIG transactivation. Thus, the blockade of AGTR1 has therapeutic potential as a novel antidepressant therapy. (C) 2018 The Author(s). Published by Elsevier Ltd.Peer reviewe

Diversidade de minhocas e atributos químicos em sistemas de plantio direto e integração lavoura-pecuária do oeste catarinense.

Resumo também apresentado no CONGRESSO DE INICIAÇÃO CIENTÍFICA E PÓS-GRADUAÇÃO, 2., 2012, São Leopoldo. Mostra de iniciação científica da UNISINOS. São Leopoldo: Casa Leiria, 2012. e-book. II CICPG. Disposição dos autores: ORSO, R.; BARTZ, M. L. C.; BROWN, G. G.; KLAUBER FILHO, O.; ROSA, M. G. da; LOCATELLI, M.; ZORTÉA, T.; CASAROTTO, K.; DECÄENS, T.; BARETTA, D

Analytical data on three Martian simulants

The preparation of planetary missions as well as the analysis of their data require a wide use of planetary simulants. They are very important for both testing mission operations and payloads, and for interpreting remote sensing data. In this work, a detailed analysis of three commercially available simulants of Martian dust and regolith is presented. Indeed, up to date, a complete data set related to their chemical, mineralogical, granulometric and spectral characters is not fully provided by their distribution and sales companies. Our dataset regards the Mars Global (MGS-1) High-Fidelity Martian Dirt Simulant [1], the Mojave Mars Simulant MMS-1 [2] and the Enhanced Mars Simulant (MMS-2) [2]. Being essential for ensuring consistency and enabling data comparison, all the chosen Martian simulants underwent the same analytical process. Grainsize data were collected using a Laser Diffraction Particle Size Analyzer. Chemical analysis was performed by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). Mineralogical analysis was carried out by X-Ray powder Diffractometry (XRD). Moreover, the largest particles of MGS-1 simulant were analyzed with the Scanning Electron Microscope (SEM-EDS) in order to confirm their chemical composition. Finally, the spectral acquisitions in the VNIR-SWIR range were taken by two Headwall Photonics hyperspectral imaging cameras. This complete series of data integrating pre-existing ones (e.g., Cannon et al. [1] and Karl et al. [2]) can in the future be used to allow a straightful choice of the right simulant for biological and life-support experiments and potential testing of mission instruments, to help inferring the composition of the Martian surface from remote sensing data, and to create new simulants or adjust the existing ones in order to get closer to the known Martian regolith variability and eventually new compositional information provided by future missions

Exploring the boundaries in an interdisciplinary context through the Family Resemblance Approach: The Dialogue Between Physics and Mathematics

Among the relevant aspects of the family resemblance approach (FRA), our study focuses on the potential of the approach to elaborate on disciplinary identities in an interdisciplinary context, specifically regarding the interplay between physics and mathematics. We present and discuss how the FRA wheel can be used and intertwined with the framework of boundary objects and boundary crossing mechanisms (Akkerman & Bakker, Review of Educational Research, 81, 132–169, 2011), which is well-known in STEM education for dealing with interdisciplinarity. The role of the FRA discussed in the article is dual: both practical and theoretical. It is practical in that we show how its use, in combination with the Akkerman and Bakker framework, appears effective in fostering productive discussions among prospective teachers on disciplinary identities and interdisciplinarity in historical cases. It is theoretical in that the combination of the two frameworks provides the vocabulary to characterise the ‘ambiguous nature’ of interdisciplinarity: like boundaries, interdisciplinarity both separates disciplines, making their identities emerge, and connects them, fostering mechanisms of crossing and transgressing the boundaries. This empirical study reveals how the theoretical elaboration took advantage of the prospective teachers’ contributions. We initially presented the FRA to characterise disciplinary identities, but the prospective teachers highlighted its potential to characterise also the boundary zone and the dialogue between physics and mathematics. The data analysis showed that the combination of the two frameworks shaped a complex learning space where there was room for very different epistemic demands of the prospective teachers: from those who feel better within the identity cores of the disciplines, to those who like to inhabit the boundary zone and others who like to re-shape boundary spaces and move dynamically across them

Dissection of the inhibition of cardiac ryanodine receptors by human glutathione transferase GSTM2-2

The muscle specific glutathione transferase GSTM2-2 inhibits the activity of cardiac ryanodine receptor (RyR2) calcium release channels with high affinity and activates skeletal RyR (RyR1) channels with lower affinity. To determine which overall region of the GSTM2-2 molecule supports binding to RyR2, we examined the effects of truncating GSTM2-2 on its ability to alter Ca2+ release from sarcoplasmic reticulum (SR) vesicles and RyR channel activity. The C-terminal half of GSTM2-2 which lacks the critical GSH binding site supported the inhibition of RyR2, but did not support activation of RyR1. Smaller fragments of GSTM2-2 indicated that the C-terminal helix 6 was crucial for the action of GSTM2-2 on RyR2. Only fragments containing the helix 6 sequence inhibited Ca2+ release from cardiac SR. Single RyR2 channels were strongly inhibited by constructs containing the helix 6 sequence in combination with adjacent helices (helices 5-8 or 4-6). Fragments containing helices 5-6 or helix 6 sequences alone had less well-defined effects. Chemical cross-linking indicated that C-terminal helices 5-8 bound to RyR2, but not RyR1. Structural analysis with circular dichroism showed that the helical content was greater in the longer helix 6 containing constructs, while the helix 6 sequence alone had minimal helical structure. Therefore the active centre of GSTM2-2 for inhibition of cardiac RyR2 involves the helix 6 sequence and the helical nature of this region is essential for its efficacy. GSTM2-2 helices 5-8 may provide the basis for RyR2-specific compounds for experimental and therapeutic use

Transient anhedonia phenotype and altered circadian timing of behaviour during night-time dim light exposure in Per3(-/-) mice, but not wildtype mice.

Industrialisation greatly increased human night-time exposure to artificial light, which in animal models is a known cause of depressive phenotypes. Whilst many of these phenotypes are 'direct' effects of light on affect, an 'indirect' pathway via altered sleep-wake timing has been suggested. We have previously shown that the Period3 gene, which forms part of the biological clock, is associated with altered sleep-wake patterns in response to light. Here, we show that both wild-type and Per3(-/-) mice showed elevated levels of circulating corticosterone and increased hippocampal Bdnf expression after 3 weeks of exposure to dim light at night, but only mice deficient for the PERIOD3 protein (Per3(-/-)) exhibited a transient anhedonia-like phenotype, observed as reduced sucrose preference, in weeks 2-3 of dim light at night, whereas WT mice did not. Per3(-/-) mice also exhibited a significantly smaller delay in behavioural timing than WT mice during weeks 1, 2 and 4 of dim light at night exposure. When treated with imipramine, neither Per3(-/-) nor WT mice exhibited an anhedonia-like phenotype, and neither genotypes exhibited a delay in behavioural timing in responses to dLAN. While the association between both Per3(-/-) phenotypes remains unclear, both are alleviated by imipramine treatment during dim night-time light

Multiple Roles of Transforming Growth Factor Beta in Amyotrophic Lateral Sclerosis

Transforming growth factor beta (TGFB) is a pleiotropic cytokine, known to be dysregulated in many neurodegenerative disorders and particularly in amyotrophic lateral sclerosis (ALS). This motor neuronal disease is non-cell autonomous, as it affects not only motor neurons, but also their surrounding glial cells, and their target skeletal muscle fibers. Here, we analyze the multiple roles of TGFB in these cell types, and how TGFB signaling is altered in ALS tissues. Data reported support a crucial involvement of TGFB in the etiology and progression of ALS, leading us to hypothesize that an imbalance of TGFB signaling, diminished at the pre-symptomatic stage and then increased with time, could be linked to ALS progression. A reduced stimulation of the TGFB pathway at the beginning of disease blocks its neuroprotective effects and promotes glutamate excitotoxicity. At later disease stages, the persistent activation of the TGFB pathway promotes an excessive microglial activation and strengthens muscular dysfunction. The therapeutic potential of TGFB is discussed here, in order to foster new approaches to treat ALS

Studio di saldabilità (LBW,FSW, EBW) di leghe da pressocolata a base alluminio

Le leghe da pressocolata sono generalmente difficilmente saldabili con i processi ad arco tradizionali acausa dei cicli termici di saldatura blandi che possono provocare la precipitazione di fasi fragili in ZTA e altempo stesso la complicata geometria dei pezzi può di fatto rendere inapplicabili certe tecnologie(saldature in interstizi non raggiungibili con torce di saldatura tradizionali). Di qui l’esigenza di uno studiodi saldabilità con processi alternativi come quelli ad energia concentrata (fascio laser e fascio elettronico) oil caratteristico processo Friction Stir che permette di saldare facilmente materiali basso fondenti come leleghe di alluminio senza portarle a fusione (fattore che in questo caso può rivelarsi molto positivo). Lo studio inquestione ha previsto l’utilizzo delle tre tecnologie di saldatura sopracitate tramite la tecnica conosciuta come“beads on plate” che consiste nella realizzazione di cordoni di saldatura direttamente su materiale base senzaunire fisicamente due pezzi ma che di fatto permette ugualmente di stabilire l’applicabilità o meno di undeterminato processo. Come materiali per la sperimentazione è stato previsto l’utilizzo di lastrinepressofuse da 2 e 4 mm di spessore, di due differenti leghe Al/Si modificate allo Stronzio riconducibili ai gruppiAlSi9Mn ed AlSi9MgMn. La prima caratterizzata dall’assenza di Magnesio, la seconda con tenori dello stessocompresi fra lo 0.1 e lo 0.5% (quindi inquadrabile come lega indurente per precipitazione)