USER EXPERIENCE WITH MODEL VALIDATION EXERCISES

Gaussian and Lagrangian model runs are evaluated in comparison to field data from the Odour Release and Odour Dispersion project and to wind tunnel data from the Mock Urban Setting Test (MUST). Different statistical metrics are discussed. To conclude which model performs best in the two cases, a weighted multiplier proposed by Sornette et al. (2007) is calculated based on each metric and finally multiplied to one score per model and experiment. The results illustrate once again that a good model performance is strongly dependent on the model input (e.g. terrain data, roughness length). Promising results are received from a combination of the Lagrangian dispersion model LASAT with wind field simulations calculated with the CFD model MISKAM

Impact of mTORC2 on mitochondrial physiology and M2 polarization in macrophages

Die Rolle vom mechanistischen Ziel von Rapamycin - Komplex 1 (mTORC1) bei der Aktivierung und beim Metabolismus von Makrophagen ist sehr gut bekannt, jedoch der Einfluss von mTOR Komplex 2 (mTORC2) auf die Aktivierung und den Metabolismus von Makrophagen ist noch nicht so gut erforscht. In den letzten Jahren wurden Studien bekannt, welche zeigten, dass der Verlust von Rictor, ein essentieller Teil der mTORC2 Kinase, zu einem hyperinflammatorischen Phänotyp in Makrophagen fuhrt, wenn sie mit TLR Liganden stimuliert werden. Um die Singifikantz von mTORC2 in Makrophagen zu charakterisieren, analysierten wir die Wundheilungseigenschaft, Apoptosisrate, Zellzyklus Progression, Glukose Aufnahme, mitochondriale Masse und mitochondriales Membranenpotential (ΔΨ) in mäuslichen Makrophagen, bei welchen Rictor genetisch gelöscht wurde (RictorΔM). Unsere Daten zeigen keinen signifikanten Unterschied in der Wundheilung, aber nach 3 Tagen Nahrungsentzug erhöhtes Zellsterben und eine, wahrscheinlich aufgrund der fehlenden Phosphorylierung von Rb durch Akt, Verzögerung in der G1 zu S Phase Passage in RictorΔM Makrophagen. Weiters fuhrte der Verlust von Rictor auch zu einer niedrigen Glukose Aufnahme, wenn die Makrophagen mit LPS oder IL-4 stimuliert wurden und zu einem verringerten ΔΨ. Interessanterweise konnte bei Stimulation von Kontrollmakrophagen durch IL-4, die Expression des M2 Markergens Arg1 durch Zugabe des Glykolyse Inhibitors 2-DG in der selben Weise gesenkt werden, wie wir es bei nicht behandelten RictorΔM Makrophagen beobachten konnten. Auch konnte Zugabe von 2-DG zu IL-4 stimulierten RictorΔM Makrophagen die Expression des Arg1 Gens nicht weiter zurück regulieren. Zusätzlich konnte auch das ΔΨ von Kontrollmakrophagen durch das Einwirken des intrazellulären Kalziumfreisetzers Thapsigargin auf das Level von RictorΔM Makrophagen angeglichen werden und wir fanden erhöhte Mengen der UPR Markerproteine GRP78 und GADD135/CHOP in RictorΔM. Zusammengefasst zeigen unsere Daten, dass mTORC2 in Makrophagen die M2 Polarisation kontrolliert, eine wichtige Rolle in der Koordination der Glukoseaufnahme und mitochondrialen Funktion spielt und dass Glykolyse auch die M2 Polarisation kontrolliert. Weiters weisen die Ergebnisse darauf hin, dass mTORC2 auch wichtig für das Erleichtern des ER Stresses in Makrophagen ist.The role of the mechanistic target of rapamycin complex 1 (mTORC1) in macrophage activation and metabolism is well characterized, whereas the impact of mTOR complex 2 (mTORC2) on macrophage activation and metabolism remains poorly understood. Recent studies have shown that loss of Rictor, a key component of mTORC2, leads to a hyperinflammatory phenotype in macrophages if challenged with TLR ligands and to high expression levels of M1 marker genes and diminished expression of M2 marker genes. To explore the significance of mTORC2 in macrophage metabolism we evaluated wound healing ability, apoptosis rate, cell cycle progression, glucose uptake, mitochondrial mass and mitochondrial membrane potential (ΔΨ) of mouse macrophages that had Rictor conditionally deleted (RictorΔM). Our data showed no significant difference in wound healing, but increased apoptosis after 3 days of serum deprivation and a distinct lag in G1 to S phase progression probably due to decreased Akt-mediated phosphorylation of Rb in RictorΔM macrophages. Moreover Rictor deletion led to a decreased glucose uptake after either LPS or IL-4 stimulation and also decreased ΔΨ. Interestingly upon IL-4 stimulation of macrophages, the glycolytic inhibitor 2-DG was able to decrease the expression of M2 marker gene Arg1 in control macrophages to the same extent as observed in untreated Rictor deficient macrophages and 2-DG also could not further downregulate Arg1 expression in RictorΔM macrophages. Furthermore upon treatment of RictorΔM and control macrophages with thapsigargin, an intracellular calcium releaser, the ΔΨ of control macrophages was lowered to the same levels as RictorΔM macrophages. Additionally we discerned increased levels of unfolded protein response (UPR) marker proteins GRP78 and GADD135/CHOP in RictorΔM macrophages. Together our data shows that mTORC2 controls M2 polarization in macrophages, is a key part in coordinating glucose uptake and mitochondrial function and that glycolysis controls M2 polarization. The results also hint at the important role of mTORC2 in alleviating ER stress in macrophages

Sigma-1 Receptor Modulation by Ligands Coordinates Cancer Cell Energy Metabolism

Sigma-1 receptor (S1R) is an important endoplasmic reticulum chaperone with various functions in health and disease. The purpose of the current work was to elucidate the involvement of S1R in cancer energy metabolism under its basal, activated, and inactivated states. For this, two cancer cell lines that differentially express S1R were treated with S1R agonist, (+)-SKF10047, and antagonist, BD1047. The effects of the agonist and antagonist on cancer energy metabolism were studied using single-cell fluorescence microscopy analysis of real-time ion and metabolite fluxes. Our experiments revealed that S1R activation by agonist increases mitochondrial bioenergetics of cancer cells while decreasing their reliance on aerobic glycolysis. S1R antagonist did not have a major impact on mitochondrial bioenergetics of tested cell lines but increased aerobic glycolysis of S1R expressing cancer cell line. Our findings suggest that S1R plays an important role in cancer energy metabolism and that S1R ligands can serve as tools to modulate it

Near-UV Light Induced ROS Production Initiates Spatial Ca2+ Spiking to Fire NFATc3 Translocation

Ca2+-dependent gene regulation controls several functions to determine the fate of the cells. Proteins of the nuclear factor of activated T-cells (NFAT) family are Ca2+ sensitive transcription factors that control the cell growth, proliferation and insulin secretion in β-cells. Translocation of NFAT proteins to the nucleus occurs in a sequence of events that starts with activating calmodulin-dependent phosphatase calcineurin in a Ca2+-dependent manner, which dephosphorylates the NFAT proteins and leads to their translocation to the nucleus. Here, we examined the role of IP3-generating agonists and near-UV light in the induction of NFATc3 migration to the nucleus in the pancreatic β-cell line INS-1. Our results show that IP3 generation yields cytosolic Ca2+ rise and NFATc3 translocation. Moreover, near-UV light exposure generates reactive oxygen species (ROS), resulting in cytosolic Ca2+ spiking via the L-type Ca2+ channel and triggers NFATc3 translocation to the nucleus. Using the mitochondria as a Ca2+ buffering tool, we showed that ROS-induced cytosolic Ca2+ spiking, not the ROS themselves, was the triggering mechanism of nuclear import of NFATc3. Collectively, this study reveals the mechanism of near-UV light induced NFATc3 migration

The contribution of uncoupling protein 2 to mitochondrial Ca2+ homeostasis in health and disease – A short revisit

Considering the versatile functions attributed to uncoupling protein 2 (UCP2) in health and disease, a profound understanding of the protein's molecular actions under physiological and pathophysiological conditions is indispensable. This review aims to revisit and shed light on the fundamental molecular functions of UCP2 in mitochondria, with particular emphasis on its intricate role in regulating mitochondrial calcium (Ca2+) uptake. UCP2′s modulating effect on various vital processes in mitochondria makes it a crucial regulator of mitochondrial homeostasis in health and disease.ISSN:1567-724

A volcanic-hazard demonstration exercise to assess and mitigate the impacts of volcanic ash clouds on civil and military aviation

International audienceAbstract. Volcanic eruptions comprise an important airborne hazard for aviation. Although significant events are rare, e.g. compared to the threat of thunderstorms, they have a very high impact. The current state of tools and abilities to mitigate aviation hazards associated with an assumed volcanic cloud was tested within an international demonstration exercise. Experts in the field assembled at the Schwarzenberg barracks in Salzburg, Austria, in order to simulate the sequence of procedures for the volcanic case scenario of an artificial eruption of the Etna volcano in Italy. The scope of the exercise ranged from the detection (based on artificial observations) of the assumed event to the issuance of early warnings. Volcanic-emission-concentration charts were generated applying modern ensemble techniques. The exercise products provided an important basis for decision-making for aviation traffic management during a volcanic-eruption crisis. By integrating the available wealth of data, observations and modelling results directly into widely used flight-planning software, it was demonstrated that route optimization measures could be implemented effectively. With timely and rather precise warnings available, the new tools and processes tested during the exercise demonstrated vividly that a vast majority of flights could be conducted despite a volcanic plume being widely dispersed within a high-traffic airspace over Europe. The resulting number of flight cancellations was minimal