121 research outputs found

    p120 catenin is required for the stress response in Drosophila

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    p120ctn is a ubiquitously expressed core component of cadherin junctions and essential for vertebrate development. Surprisingly, Drosophila p120ctn (dp120ctn) is dispensable for adherens junctions and development, which has discouraged Drosophila researchers from further pursuing the biological role of dp120ctn. Here we demonstrate that dp120ctn loss results in increased heat shock sensitivity and reduced animal lifespan, which are completely rescued by ectopic expression of a dp120ctn-GFP transgene. Transcriptomic analysis revealed multiple relish/NF-κB target genes differentially expressed upon loss of dp120ctn. Importantly, this aberrant gene expression was rescued by overexpression of dp120ctn-GFP or heterozygosity for relish. Our results uncover a novel role for dp120ctn in the regulation of animal stress response and immune signalling. This may represent an ancient role of p120ctn and can influence further studies in Drosophila and mammals

    Bursicon: a novel regulator of intestinal homeostasis and systemic metabolism in adult Drosophila

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    Maintaining systemic energy homeostasis is crucial for the physiology of all living organisms. This process involves a tight control of cellular and organismal metabolic functions, which are required to coordinate energy intake and energy expenditure. Disruption of this balance can lead to major human pathologies, such as diabetes, obesity and lipodystrophy. A central regulator of systemic metabolism is the intestine. The intestinal epithelium is responsible for nutrient absorption, as well as being a key-endocrine and immune tissue. Due to its endocrine function, the intestine orchestrates the communication between multiple organs, which is required to maintain organismal fitness in response to changing environmental and nutrient demands. Functional studies on inter-organ communication are often challenging in mammalian systems, due to their complex physiology. A simpler, yet relevant organism like Drosophila melanogaster has proven to be an invaluable alternative model system to study complex physiological processes. In this thesis we used Drosophila melanogaster as a paradigm to study how the intestine communicates with other tissues through its endocrine function to regulate systemic metabolic homeostasis. We found that systemic secretion of the intestinal enteroendocrine derived hormone Bursicon is regulated by nutrients and maintains metabolic homeostasis via its neuronal receptor LGR2. Impairment of Bursicon/ neuronal LGR2 signalling resulted in extensive loss of stored energy resources, especially lipids. Our data provides new insights into intestinal endocrine regulation of metabolic homeostasis. Our work identified a novel gut/brain axis controlling key metabolic tissues. Using Drosophila to identify gut-dependent hormonal metabolic networks will help to gain a deeper knowledge of how organs communicate with each other to maintain systemic metabolic homeostasis, which could impact the identification of therapeutic targets for metabolic disorders in humans

    Processing and Formulation of Concentrated Protein Solutions - Strategies for their Characterization and Stabilization

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    Biopharmaceutics are used for therapy of human diseases. Requiring high purity, their downstream process consists of several orthogonal process steps to remove contaminants. Due to increasing product concentrations, these process units are increasingly confronted to cope with concentrated protein solutions. This work describes strategies to characterize protein interactions, aggregation, and dynamic viscosity of concentrated protein solutions in order to improve their processing and formulation

    High-throughput dissolution/permeation screening : a 96-well two-compartment microplate approach

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    Early formulation screening can alleviate development of advanced oral drug formulations, such as amorphous solid dispersions (ASDs). Traditionally, dissolution is used to predict ASD performance. Here, a high-throughput approach is described that simultaneously screens drug dissolution and permeation employing a two-compartment 96-well plate. Freeze-drying from hydro-alcoholic solutions was used to prepare amorphous formulations. The screening approach was tested on amorphous and crystalline tadalafil formulations with and without Soluplus®. The workflow consisted of: 1) dispersion of the formulations; 2) incubation within the two-compartment plate, where a dialysis membrane separated donor (dispersed formulation) and acceptor; 3) sampling (donor and acceptor), where donor samples were centrifuged to remove non-dissolved material; and 4) quantification by UHPLC-UV. To identify optimal screening conditions, the following parameters were varied: dispersion medium (buffer / biomimetic media), acceptor medium (buffer / surfactant solutions), and incubation time (1, 3, and 6 h). Surfactants (acceptor) increased tadalafil permeation. Biomimetic medium (donor) enhanced dissolution, but not permeation, except for freeze-dried tadalafil, for which the permeated amount increased. The predictiveness was evaluated by comparing dissolution-/permeation-results with in vivo bioavailability. In general, both dissolution and permeation reflected bioavailability, whereof the latter was a better predictor. High-throughput dissolution/permeation is regarded promising for formulation screening

    A neuronal relay mediates a nutrient responsive gut/fat body axis regulating energy homeostasis in adult Drosophila

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    The control of systemic metabolic homeostasis involves complex inter-tissue programs that coordinate energy production, storage, and consumption, to maintain organismal fitness upon environmental challenges. The mechanisms driving such programs are largely unknown. Here, we show that enteroendocrine cells in the adult Drosophila intestine respond to nutrients by secreting the hormone Bursicon α, which signals via its neuronal receptor DLgr2. Bursicon α/DLgr2 regulate energy metabolism through a neuronal relay leading to the restriction of glucagon-like, adipokinetic hormone (AKH) production by the corpora cardiaca and subsequent modulation of AKH receptor signaling within the adipose tissue. Impaired Bursicon α/DLgr2 signaling leads to exacerbated glucose oxidation and depletion of energy stores with consequent reduced organismal resistance to nutrient restrictive conditions. Altogether, our work reveals an intestinal/neuronal/adipose tissue inter-organ communication network that is essential to restrict the use of energy and that may provide insights into the physiopathology of endocrine-regulated metabolic homeostasis

    MicroRNA-200c Attenuates the Tumor-Infiltrating Capacity of Macrophages

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    Macrophages constitute a major part of the tumor-infiltrating immune cells. Within the tumor microenvironment, they acquire an alternatively activated, tumor-supporting phenotype. Factors released by tumor cells are crucial for the recruitment of tumor-associated macrophages. In the present project, we aimed to understand the role of hsa-miR-200c-3p (miR-200c) in the interplay between tumor cells and macrophages. To this end, we employed a coculture system of MCF7 breast tumor cells and primary human macrophages and observed the transfer of miR-200c from apoptotic tumor cells to macrophages, which required intact CD36 receptor in macrophages. We further comprehensively determined miR-200c targets in macrophages by mRNA-sequencing and identified numerous migration-associated mRNAs to be downregulated by miR-200c. Consequently, miR-200c attenuated macrophage infiltration into 3-dimensional tumor spheroids. miR-200c-mediated reduction in infiltration further correlated with a miR-200c migration signature comprised of the four miR-200c-repressed, predicted targets PPM1F, RAB11FIB2, RDX, and MSN

    Analyse der Einkaufsentscheidungen von Kantinen in Brandenburg im Hinblick auf Regionalität

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    Dieser Beitrag stellt Entscheidungskriterien für brandenburgische Kantinen hinsichtlich der Versorgung mit regionalen Produkten vor und zeigt Herausforderungen und Hemmnisse auf. Einschränkungen für Kantinen sind wirtschaftliche Rahmenbedingungen, Nachfrage sowie Versorgungssicherheit

    Valuing Alzheimer's Disease drugs:A health technology assessment perspective on outcomes

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    ObjectivesDue to the nature of Alzheimer's disease (AD), health technology assessment (HTA) agencies might face considerable challenges in choosing appropriate outcomes and outcome measures for drugs that treat the condition. This study sought to understand which outcomes informed previous HTAs, to explore possible reasons for prioritizations, and derive potential implications for future assessments of AD drugs.MethodWe conducted a literature review of studies that analyzed decisions made in HTAs (across disease areas) in three European countries: England, Germany, and The Netherlands. We then conducted case studies of technology assessments conducted for AD drugs in these countries.ResultsOverall, outcomes measured using clinical scales dominated decisions or recommendations about whether to fund AD drugs, or price negotiations. HTA processes did not always allow the inclusion of outcomes relevant to people with AD, their carers, and families. Processes did not include early discussion and agreement on what would constitute appropriate outcome measures and cut-off points for effects.ConclusionsWe conclude that in order to ensure that future AD drugs are valued appropriately and timely, early agreement with various stakeholders about outcomes, outcome measures, and cut-offs is important

    Time course of changes in motor-cognitive exergame performances during task-specific training in patients with dementia: identification and predictors of early training response

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    Background: Some studies have already suggested that exergame interventions can be effective to improve physical, cognitive, motor-cognitive, and psychological outcomes in patients with dementia (PwD). However, little is known about the training volume required to induce such positive effects and the inter-individual differences in training response among PwD. The aim of the study was to analyze the time course of changes in motor-cognitive exergame performances during a task-specific training program and to identify predictors of early training response in PwD. Methods: Secondary analyses of data from the intervention group (IG) of a randomized, placebo-controlled trial to improve motor-cognitive performances in PwD. Fifty-six geriatric patients with mild-to-moderate dementia randomized to the IG underwent a 10-week, task-specific training program (2×/week) on an exergame-based balance training system (Physiomat®), combining postural control tasks with cognitive tasks of an established neuropsychological test (Trail Making Test). Main outcome was the time required to complete different Physiomat®-Tasks (PTs) assessed at baseline (T1), training session 7 (TS7) and 14 (TS14), and post-intervention after 20 training sessions (T2). Reliable change indices were used to identify early responders from T1 to TS7. A multivariate logistic regression analysis was performed to determine independent predictors of early training response. Results: Completion time significantly improved already from T1 to TS7 in all PTs (p ≤ .001–.006), with moderate to very large effect sizes (r = .38–.52; Cohen’s d = .85–1.45). For most PTs, significant progressive improvements from TS7 to TS14 and TS14 to T2 were not observed. Thirty-one (59.6%) participants were classified as early responders and 21 (40.4%) as non-early responders. Lower baseline exergame performance and lower visuospatial and divided attention abilities were independently associated with early training response. Conclusions: Substantial task-specific improvements in complex motor-cognitive exergame performances can be obtained within a surprisingly short intervention period in PwD. Our results confirm that not only an excellent training response can be achieved in this patient population, but also that more vulnerable patients with greater deficits in domain-specific cognitive functions associated with fall risk may even reap the most and fastest benefit from motor-cognitive exergame interventions. Trial registration: ISRCTN registry, ISRCTN37232817 (retrospectively registered on 04/02/2012)

    Live cell imaging reveals 3 '-UTR dependent mRNA sorting to synapses

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    mRNA transport restricts translation to specific subcellular locations, which is the basis for many cellular functions. However, the precise process of mRNA sorting to synapses in neurons remains elusive. Here we use Rgs4 mRNA to investigate 3'-UTR-dependent transport by MS2 live-cell imaging. The majority of observed RNA granules display 3'-UTR independent bidirectional transport in dendrites. Importantly, the Rgs4 3'-UTR causes an anterograde transport bias, which requires the Staufen2 protein. Moreover, the 3'-UTR mediates dynamic, sustained mRNA recruitment to synapses. Visualization at high temporal resolution enables us to show mRNA patrolling dendrites, allowing transient interaction with multiple synapses, in agreement with the sushi-belt model. Modulation of neuronal activity by either chemical silencing or local glutamate uncaging regulates both the 3'-UTR-dependent transport bias and synaptic recruitment. This dynamic and reversible mRNA recruitment to active synapses would allow translation and synaptic remodeling in a spatially and temporally adaptive manner
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