90 research outputs found

    Acetylation of lysine 109 modulates pregnane X receptor DNA binding and transcriptional activity

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    Pregnane X receptor (PXR) is a major transcriptional regulator of xenobiotic metabolism and transport pathways in the liver and intestines, which are critical for protecting organisms against potentially harmful xenobiotic and endobiotic compounds. Inadvertent activation of drug metabolism pathways through PXR is known to contribute to drug resistance, adverse drug–drug interactions, and drug toxicity in humans. In both humans and rodents, PXR has been implicated in non-alcoholic fatty liver disease, diabetes, obesity, inflammatory bowel disease, and cancer. Because of PXR's important functions, it has been a therapeutic target of interest for a long time. More recent mechanistic studies have shown that PXR is modulated by multiple PTMs. Herein we provide the first investigation of the role of acetylation in modulating PXR activity. Through LC–MS/MS analysis, we identified lysine 109 (K109) in the hinge as PXR's major acetylation site. Using various biochemical and cell-based assays, we show that PXR's acetylation status and transcriptional activity are modulated by E1A binding protein (p300) and sirtuin 1 (SIRT1). Based on analysis of acetylation site mutants, we found that acetylation at K109 represses PXR transcriptional activity. The mechanism involves loss of RXRα dimerization and reduced binding to cognate DNA response elements. This mechanism may represent a promising therapeutic target using modulators of PXR acetylation levels

    The Flattened Dark Matter Halo of M31 as Deduced from the Observed HI Scale Heights

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    In this paper, we use the outer-galactic HI scale height data as well as the observed rotation curve as constraints to determine the halo density distribution of the Andromeda galaxy (M31). We model the galaxy as a gravitationally-coupled system of stars and gas, responding to the external force-field of a known Hernquist bulge and the dark matter halo, the density profile of the latter being characterized by four free parameters. The parameter space of the halo is optimized so as to match the observed HI thickness distribution as well as the rotation curve on an equal footing, unlike the previous studies of M31 which were based on rotation curves alone. We show that an oblate halo, with an isothermal density profile, provides the best fit to the observed data. This gives a central density of 0.011 M_sun /pc^3, a core radius of 21 kpc, and an axis ratio of 0.4. The main result from this work is the flattened dark matter halo for M31, which is required to match the outer galactic HI scale height data. Interestingly, such flattened halos lie at the most oblate end of the distribution of halo shapes found in recent cosmological simulations.Comment: 21 pages, 6 figures, accepted for publication in the Astrophysical Journa

    Towards an operationalisation of nature-based solutions for natural hazards

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    Nature-based solutions (NBS) are being promoted as adaptive measures against predicted increasing hydrometeorological hazards (HMHs), such as heatwaves and floods which have already caused significant loss of life and economic damage across the globe. However, the underpinning factors such as policy framework, end-users' interests and participation for NBS design and operationalisation are yet to be established. We discuss the operationalisation and implementation processes of NBS by means of a novel concept of Open-Air Laboratories (OAL) for its wider acceptance. The design and implementation of environmentally, economically, technically and socio-culturally sustainable NBS require inter- and transdisciplinary approaches which could be achieved by fostering co-creation processes by engaging stakeholders across various sectors and levels, inspiring more effective use of skills, diverse knowledge, manpower and resources, and connecting and harmonising the adaptation aims. The OAL serves as a benchmark for NBS upscaling, replication and exploitation in policy-making process through monitoring by field measurement, evaluation by key performance indicators and building solid evidence on their short- and long-term multiple benefits in different climatic, environmental and socio-economic conditions, thereby alleviating the challenges of political resistance, financial barriers and lack of knowledge. We conclude that holistic management of HMHs by effective use of NBS can be achieved with standard compliant data for replicating and monitoring NBS in OALs, knowledge about policy silos and interaction between research communities and end-users. Further research is needed for multi-risk analysis of HMHs and inclusion of NBS into policy frameworks, adaptable at local, regional and national scales leading to modification in the prevalent guidelines related to HMHs. The findings of this work can be used for developing synergies between current policy frameworks, scientific research and practical implementation of NBS in Europe and beyond for its wider acceptance

    Structural Brain Magnetic Resonance Imaging to Rule out Comorbid Pathology in the Assessment of Alzheimer\u27s Disease Dementia: Findings from the Ontario Neurodegenerative Disease Research Initiative (ONDRI) Study and Clinical Trials over the Past 10 Years

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    Background/Objective: Structural brain magnetic resonance imaging (MRI) is not mandatory in Alzheimer\u27s disease (AD) research or clinical guidelines. We aimed to explore the use of structural brain MRI in AD/mild cognitive impairment (MCI) trials over the past 10 years and determine the frequency with which inclusion of standardized structural MRI acquisitions detects comorbid vascular and non-vascular pathologies. Methods: We systematically searched ClinicalTrials.gov for AD clinical trials to determine their neuroimaging criteria and then used data from an AD/MCI cohort who underwent standardized MRI protocols, to determine type and incidence of clinically relevant comorbid pathologies. Results: Of 210 AD clinical trials, 105 (50%) included structural brain imaging in their eligibility criteria. Only 58 (27.6%) required MRI. 16,479 of 53,755 (30.7%) AD participants were in trials requiring MRI. In the observational AD/MCI cohort, 141 patients met clinical criteria; 22 (15.6%) had relevant MRI findings, of which 15 (10.6%) were exclusionary for the study. Discussion: In AD clinical trials over the last 10 years, over two-thirds of participants could have been enrolled without brain MRI and half without even a brain CT. In a study sample, relevant comorbid pathology was found in 15% of participants, despite careful screening. Standardized structural MRI should be incorporated into NIA-AA diagnostic guidelines (when available) and research frameworks routinely to reduce diagnostic heterogeneity

    Study on Bonding Insurance Contract

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    保证保险产生于西方国家,中国引进保证保险业务的时间还不长。在短短的时间内,保证保险显示了广阔的市场需求,但同时也矛盾重重。保证保险的法律关系相对较为复杂,保险公司的经营风险相对较高。对于保证保险合同的法律性质一直以来都引起很大的争议。争议的焦点在于保证保险合同是保证担保合同还是保险合同。我国对于保证保险的法律制度及配套体系滞后,理论界和实务界也莫衷一是。本文从分析保证保险合同的法律关系入手,通过比较分析的方法深入分析保证保险的法律性质,全面探讨保证保险在审判实践中存在的主要问题,最后对如何完善保证保险制度提出立法建议和对策。论文除了引言和结束语外,主要分为四章。 第一章保证保险概述。在保证保...Bonding insurance generated in the western countries. It was introduced into China for not very long. In this short time, bonding insurance showed its expansive market. But the conflicts also exist. Comparatively, the legal relationship of bonding insurance is complicated and the risk of the insurance company is high. There is much dispute on the nature of bonding insurance all the time. The dispu...学位:法律硕士院系专业:法学院法律系_法律硕士(JM)学号:20040814

    ATG7 regulates energy metabolism, differentiation and survival of Philadelphia chromosome-positive cells

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    A major drawback of tyrosine kinase inhibitor (TKI) treatment in chronic myeloid leukemia (CML) is that primitive CML cells are able to survive TKI-mediated BCR-ABL inhibition, leading to disease persistence in patients. Investigation of strategies aiming to inhibit alternative survival pathways in CML is therefore critical. We have previously shown that a nonspecific pharmacological inhibition of autophagy potentiates TKI-induced death in Philadelphia chromosome-positive cells. Here we provide further understanding of how specific and pharmacological autophagy inhibition affects nonmitochondrial and mitochondrial energy metabolism and reactive oxygen species (ROS)-mediated differentiation of CML cells and highlight ATG7 (a critical component of the LC3 conjugation system) as a potential specific therapeutic target. By combining extra- and intracellular steady state metabolite measurements by liquid chromatography-mass spectrometry with metabolic flux assays using labeled glucose and functional assays, we demonstrate that knockdown of ATG7 results in decreased glycolysis and increased flux of labeled carbons through the mitochondrial tricarboxylic acid cycle. This leads to increased oxidative phosphorylation and mitochondrial ROS accumulation. Furthermore, following ROS accumulation, CML cells, including primary CML CD34+ progenitor cells, differentiate toward the erythroid lineage. Finally, ATG7 knockdown sensitizes CML progenitor cells to TKI-induced death, without affecting survival of normal cells, suggesting that specific inhibitors of ATG7 in combination with TKI would provide a novel therapeutic approach for CML patients exhibiting persistent disease

    Towards operationalisation of nature-based solutions for natural hazards

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    Nature-based solutions (NBS) are being promoted as adaptive measures against predicted increasing hydrometeorological hazards (HMHs), such as heatwaves and floods which have already caused significant loss of life and economic damage across the globe. However, the underpinning factors such as policy framework, end-users' interests and participation for NBS design and operationalisation are yet to be established. We discuss the operationalisation and implementation processes of NBS by means of a novel concept of Open-Air Laboratories (OAL) for its wider acceptance. The design and implementation of environmentally, economically, technically and socio-culturally sustainable NBS require inter- and transdisciplinary approaches which could be achieved by fostering co-creation processes by engaging stakeholders across various sectors and levels, inspiring more effective use of skills, diverse knowledge, manpower and resources, and connecting and harmonising the adaptation aims. The OAL serves as a benchmark for NBS upscaling, replication and exploitation in policy-making process through monitoring by field measurement, evaluation by key performance indicators and building solid evidence on their short- and long-term multiple benefits in different climatic, environmental and socio-economic conditions, thereby alleviating the challenges of political resistance, financial barriers and lack of knowledge. We conclude that holistic management of HMHs by effective use of NBS can be achieved with standard compliant data for replicating and monitoring NBS in OALs, knowledge about policy silos and interaction between research communities and end-users. Further research is needed for multi-risk analysis of HMHs and inclusion of NBS into policy frameworks, adaptable at local, regional and national scales leading to modification in the prevalent guidelines related to HMHs. The findings of this work can be used for developing synergies between current policy frameworks, scientific research and practical implementation of NBS in Europe and beyond for its wider acceptance
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