The importance of ubiquitin in the trafficking of the insulin responsive glucose transporter GLUT4

The regulation of blood glucose levels in humans, in response to insulin, is essential to survival. This response is mediated through the insulin responsive glucose transporter GLUT4. In response to insulin stimulation GLUT4 is trafficked from intracellular insulin sensitive stores (GSVs GLUT4 storage vesicles) to the plasma membrane of fat and muscle cells allowing uptake of glucose into these cells and lowering of plasma glucose levels. Previous work from our lab has identified that ubiquitination and subsequent deubiquitination of GLUT4 is required for entry and stability in GSVs. This balance of ubiquitination and deubiquitination in mammalian cells is carried out by E3 ligases and deubiqutinating enzymes (DUBs). It appears that E3 ligases allow for targeted entry of GLUT4 into insulin sensitive GSVs and that the DUB USP25 is required for GLUT4 to stably maintained in these GSVs. Using a model developed in our lab my thesis looked at key steps of ubiquitination and deubiquitination to try and identify the E3 ligases and deubiquinases essential for entry and stability of GLUT4 into GLUT4 storage vesicles. Previous work in our lab identified that knockdown of the ubiquitin specific protease USP25 resulted in a reduction in GLUT4 levels in 3T3-L1 adipocytes. In my thesis I looked at using an inducible retro viral system to identify if the catalytic activity of USP25 was required to maintain GLUT4 expression levels. This method had limited success as I was unable to produce a virus that would always express under induction. Previous work in our lab had also identified that GLUT4 was ubiquitinated in yeast and in 3T3-L1 adipocytes. βTrCP had previously been identified as a possible E3 ligase that interacts with GLUT4 and so I used this as a candidate ligase. To identify if βTrCP played a role in mediating insulin responsive glucose uptake I utilised siRNA knockdown of βTrCP in 3T3-L1 adipocytes alongside glucose uptake assays. Although knockdown of βTrCP showed no effect on GLUT4 levels in 3T3-L1 adipocytes it did show a decrease in insulin responsive glucose uptake. These data did not provide any further information on the relationship between GLUT4 and USP25. These data do however indicate that βTrCP does interact in some way with insulin responsive glucose uptake in 3T3-L1 adipocytes but it is still unclear if this is due to any interaction with GLUT4

Humanities for the environment—A manifesto for research and action

Human preferences, practices and actions are the main drivers of global environmental change in the 21st century. It is crucial, therefore, to promote pro-environmental behavior. In order to accomplish this, we need to move beyond rational choice and behavioral decision theories, which do not capture the full range of commitments, assumptions, imaginaries, and belief systems that drive those preferences and actions. Humanities disciplines, such as philosophy, history, religious studies, gender studies, language and literary studies, psychology, and pedagogics do offer deep insights into human motivations, values, and choices. We believe that the expertise of such fields for transforming human preferences, practices and actions is ignored at society’s peril. We propose an agenda that focuses global humanities research on stepping up to the challenges of planetary environmental change. We have established Environmental Humanities Observatories through which to observe, explore and enact the crucial ways humanistic disciplines may help us understand and engage with global ecological problems by providing insight into human action, perceptions, and motivation. We present this Manifesto as an invitation for others to join the “Humanities for the Environment” open global consortium of humanities observatories as we continue to develop a shared research agenda

Lunar Propellant Factory Mission Design To Sustain Future Human Exploration

The International Space Exploration Coordination Group (ISECG) Global Exploration Roadmap (GER) is the standard document reflecting the current focus of the leading space agencies that envision space exploration missions beyond Low Earth Orbit (LEO), returning to the Moon and going to Mars in the upcoming years. The roadmap showcases the Moon as a stepping-stone for further human space exploration, by setting up a sustainable space infrastructure on its surface an orbit. Inspired from this vision, we present the result of a phase A study about a lunar propellant factory near the Shackleton south-pole crater relying on In-Situ Resources Utilization (ISRU) to produce and sell Liquid Oxygen (LOX) on the moon surface and in orbit. The overall timeline of the mission is in line with the ISECG exploration roadmap Moon phase, based on realistic technologies of advanced-enough Technology Readiness Levels (TRL). It is a second iteration on the Lunar Propellant Outpost (LUPO) mission architecture, presented during IAC 2018. We preserved and reviewed the original building blocks (Habitats, Crew Mobility Elements, ISRU Facilities, and Lunar Spaceport) of the LUPO mission architecture, and further improved the mission design, supported by trade-off analysis on different mission scenarios. An extensive analysis and optimisation have been performed on ISRU processes and surface electrical power management, the core of our infrastructure. The mission architecture also includes crew on the lunar surface, so life support systems and habitat, as well as operations concepts, have been studied in-depth, and a synthesis of all results is presented. The main aim of this iteration was to improve and refine the baseline infrastructural and technological design architecture of LUPO and reflect on missions going beyond the Moon by providing refuelling services, with sustainability and economic viability in mind

The deubiquitinating enzyme USP25 binds tankyrase and regulates trafficking of the facilitative glucose transporter GLUT4 in adipocytes

Key to whole body glucose homeostasis is the ability of fat and muscle cells to sequester the facilitative glucose transporter GLUT4 in an intracellular compartment from where it can be mobilized in response to insulin. We have previously demonstrated that this process requires ubiquitination of GLUT4 while numerous other studies have identified several molecules that are also required, including the insulin-responsive aminopeptidase IRAP and its binding partner, the scaffolding protein tankyrase. In addition to binding IRAP, Tankyrase has also been shown to bind the deubiquinating enzyme USP25. Here we demonstrate that USP25 and Tankyrase interact, and colocalise with GLUT4 in insulin-sensitive cells. Furthermore depletion of USP25 from adipocytes reduces cellular levels of GLUT4 and concomitantly blunts the ability of insulin to stimulate glucose transport. Collectively, these data support our model that sorting of GLUT4 into its insulin-sensitive store involves a cycle of ubiquitination and subsequent deubiquitinatio

Leadership in compassionate care programme: final report.

The Leadership in Compassionate Care programme is a collaborative venture between Edinburgh Napier University and NHS Lothian and is supported by a generous benefactor. The aim of the 3 year project is to ensure that compassionate nursing practice is integral to care within NHS Lothian and within the undergraduate nursing programme at Napier University. An important part of this programme is to disseminate both the learning and outcomes to other organisations.The programme has 4 key strands which are: Embedding the principles of Compassionate Care with in the undergraduate curriculum. Supporting newly qualified nurses during their first year in practice to facilitate the transition from student to competent and compassionate staff nurse. Establishing NHS Lothian centres of excellence in Compassionate Care – called Beacon Wards. Supporting development of leadership skills in Compassionate Care in NHS Lothian

High-sensitivity troponin in the evaluation of patients with suspected acute coronary syndrome: a stepped-wedge, cluster-randomised controlled trial.

BACKGROUND: High-sensitivity cardiac troponin assays permit use of lower thresholds for the diagnosis of myocardial infarction, but whether this improves clinical outcomes is unknown. We aimed to determine whether the introduction of a high-sensitivity cardiac troponin I (hs-cTnI) assay with a sex-specific 99th centile diagnostic threshold would reduce subsequent myocardial infarction or cardiovascular death in patients with suspected acute coronary syndrome. METHODS: In this stepped-wedge, cluster-randomised controlled trial across ten secondary or tertiary care hospitals in Scotland, we evaluated the implementation of an hs-cTnI assay in consecutive patients who had been admitted to the hospitals' emergency departments with suspected acute coronary syndrome. Patients were eligible for inclusion if they presented with suspected acute coronary syndrome and had paired cardiac troponin measurements from the standard care and trial assays. During a validation phase of 6-12 months, results from the hs-cTnI assay were concealed from the attending clinician, and a contemporary cardiac troponin I (cTnI) assay was used to guide care. Hospitals were randomly allocated to early (n=5 hospitals) or late (n=5 hospitals) implementation, in which the high-sensitivity assay and sex-specific 99th centile diagnostic threshold was introduced immediately after the 6-month validation phase or was deferred for a further 6 months. Patients reclassified by the high-sensitivity assay were defined as those with an increased hs-cTnI concentration in whom cTnI concentrations were below the diagnostic threshold on the contemporary assay. The primary outcome was subsequent myocardial infarction or death from cardiovascular causes at 1 year after initial presentation. Outcomes were compared in patients reclassified by the high-sensitivity assay before and after its implementation by use of an adjusted generalised linear mixed model. This trial is registered with ClinicalTrials.gov, number NCT01852123. FINDINGS: Between June 10, 2013, and March 3, 2016, we enrolled 48 282 consecutive patients (61 [SD 17] years, 47% women) of whom 10 360 (21%) patients had cTnI concentrations greater than those of the 99th centile of the normal range of values, who were identified by the contemporary assay or the high-sensitivity assay. The high-sensitivity assay reclassified 1771 (17%) of 10 360 patients with myocardial injury or infarction who were not identified by the contemporary assay. In those reclassified, subsequent myocardial infarction or cardiovascular death within 1 year occurred in 105 (15%) of 720 patients in the validation phase and 131 (12%) of 1051 patients in the implementation phase (adjusted odds ratio for implementation vs validation phase 1·10, 95% CI 0·75 to 1·61; p=0·620). INTERPRETATION: Use of a high-sensitivity assay prompted reclassification of 1771 (17%) of 10 360 patients with myocardial injury or infarction, but was not associated with a lower subsequent incidence of myocardial infarction or cardiovascular death at 1 year. Our findings question whether the diagnostic threshold for myocardial infarction should be based on the 99th centile derived from a normal reference population. FUNDING: The British Heart Foundation