42 research outputs found

    History of genome editing: From meganucleases to CRISPR.

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    CRISPR-mediated genome editing has undoubtedly revolutionized genetic engineering of animals. With the ability for virtually unlimited modification of almost any genome it is easy to forget which amazing discoveries paved the way for this groundbreaking technology. Here, we summarize the history of genome editing platforms, starting from enhanced integration of foreign DNA by meganuclease-mediated double strand breaks to CRISPR/Cas9, the leading technology to date, and its re-engineered variants

    A novel panel of mouse models to evaluate the role of human pregnane X receptor and constitutive androstane receptor in drug response

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    The pregnane X receptor (PXR) and the constitutive androstane receptor (CAR) are closely related orphan nuclear hormone receptors that play a critical role as xenobiotic sensors in mammals. Both receptors regulate the expression of genes involved in the biotransformation of chemicals in a ligand-dependent manner. As the ligand specificity of PXR and CAR have diverged between species, the prediction of in vivo PXR and CAR interactions with a drug are difficult to extrapolate from animals to humans. We report the development of what we believe are novel PXR- and CAR-humanized mice, generated using a knockin strategy, and Pxr- and Car-KO mice as well as a panel of mice including all possible combinations of these genetic alterations. The expression of human CAR and PXR was in the predicted tissues at physiological levels, and splice variants of both human receptors were expressed. The panel of mice will allow the dissection of the crosstalk between PXR and CAR in the response to different drugs. To demonstrate the utility of this panel of mice, we used the mice to show that the in vivo induction of Cyp3a11 and Cyp2b10 by phenobarbital was only mediated by CAR, although this compound is described as a PXR and CAR activator in vitro. This panel of mouse models is a useful tool to evaluate the roles of CAR and PXR in drug bioavailability, toxicity, and efficacy in humans

    Проектирование системы электроснабжения базы по обслуживанию нефтегазодобывающего месторождения

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    Выпускная квалификационная работа 136 с., 19 рис., 60 табл., 24 источника, 4 приложения. Объектом исследования является ремонтно-механический цех базы по обслуживанию нефтегазодобывающего месторождения. Цель работы: Проектирование системы электроснабжения базы по облуживанию нефтегазодобывающего месторождения. Экономическое обоснование принятых решений. В процессе исследования произведен расчет нагрузок ремонтно-механического цеха и базы в целом с применением различных методов, выбор метода расчета производился на основе исходных данных, а также осуществлен выборThis graduate qualification work includes 136 p., 19 fig., 60 tables, 24 ones in list of references and 4 transcripts. The subject of research is mechanical repair shop of upstream and gas production field operation base. Work objective is energy supply system designing of upstream and gas production field operation base and its business case. In the course of investigations there was estimated a load analysis of upstream and gas production field operation base and its mechanical repair shop by different methods, based on input data. Also there were steps of the equipment selection and its testing of several operations. As a result of investigation the model of such base was engineered, and there was shown its commercial importance and ecological security. Range of application: petro

    Early-Onset and Robust Amyloid Pathology in a New Homozygous Mouse Model of Alzheimer's Disease

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    BACKGROUND: Transgenic mice expressing mutated amyloid precursor protein (APP) and presenilin (PS)-1 or -2 have been successfully used to model cerebral beta-amyloidosis, one of the characteristic hallmarks of Alzheimer's disease (AD) pathology. However, the use of many transgenic lines is limited by premature death, low breeding efficiencies and late onset and high inter-animal variability of the pathology, creating a need for improved animal models. Here we describe the detailed characterization of a new homozygous double-transgenic mouse line that addresses most of these issues. METHODOLOGY/PRINCIPAL FINDINGS: The transgenic mouse line (ARTE10) was generated by co-integration of two transgenes carrying the K670N/M671L mutated amyloid precursor protein (APP(swe)) and the M146V mutated presenilin 1 (PS1) both under control of a neuron-specific promoter. Mice, hemi- as well as homozygous for both transgenes, are viable and fertile with good breeding capabilities and a low rate of premature death. They develop robust AD-like cerebral beta-amyloid plaque pathology with glial inflammation, signs of neuritic dystrophy and cerebral amyloid angiopathy. Using our novel image analysis algorithm for semi-automatic quantification of plaque burden, we demonstrate an early onset and progressive plaque deposition starting at 3 months of age in homozygous mice with low inter-animal variability and 100%-penetrance of the phenotype. The plaques are readily detected in vivo by PiB, the standard human PET tracer for AD. In addition, ARTE10 mice display early loss of synaptic markers and age-related cognitive deficits. By applying a gamma-secretase inhibitor we show a dose dependent reduction of soluble amyloid beta levels in the brain. CONCLUSIONS: ARTE10 mice develop a cerebral beta-amyloidosis closely resembling the beta-amyloid-related aspects of human AD neuropathology. Unifying several advantages of previous transgenic models, this line particularly qualifies for the use in target validation and for evaluating potential diagnostic or therapeutic agents targeting the amyloid pathology of AD

    A MAFG-lncRNA axis links systemic nutrient abundance to hepatic glucose metabolism

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    Obesity and type 2 diabetes mellitus are global emergencies and long noncoding RNAs (lncRNAs) are regulatory transcripts with elusive functions in metabolism. Here we show that a high fraction of lncRNAs, but not protein-coding mRNAs, are repressed during diet-induced obesity (DIO) and refeeding, whilst nutrient deprivation induced lncRNAs in mouse liver. Similarly, lncRNAs are lost in diabetic humans. LncRNA promoter analyses, global cistrome and gain-of-function analyses confirm that increased MAFG signaling during DIO curbs lncRNA expression. Silencing Mafg in mouse hepatocytes and obese mice elicits a fasting-like gene expression profile, improves glucose metabolism, de-represses lncRNAs and impairs mammalian target of rapamycin (mTOR) activation. We find that obesity-repressed LincIRS2 is controlled by MAFG and observe that genetic and RNAi-mediated LincIRS2 loss causes elevated blood glucose, insulin resistance and aberrant glucose output in lean mice. Taken together, we identify a MAFG-lncRNA axis controlling hepatic glucose metabolism in health and metabolic disease

    A MAFG-lncRNA axis links systemic nutrient abundance to hepatic glucose metabolism

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    Obesity and type 2 diabetes mellitus are global emergencies and long noncoding RNAs (lncRNAs) are regulatory transcripts with elusive functions in metabolism. Here we show that a high fraction of lncRNAs, but not protein-coding mRNAs, are repressed during diet-induced obesity (DIO) and refeeding, whilst nutrient deprivation induced lncRNAs in mouse liver. Similarly, lncRNAs are lost in diabetic humans. LncRNA promoter analyses, global cistrome and gain-of-function analyses confirm that increased MAFG signaling during DIO curbs lncRNA expression. Silencing Mafg in mouse hepatocytes and obese mice elicits a fasting-like gene expression profile, improves glucose metabolism, de-represses lncRNAs and impairs mammalian target of rapamycin (mTOR) activation. We find that obesity-repressed LincIRS2 is controlled by MAFG and observe that genetic and RNAi-mediated LincIRS2 loss causes elevated blood glucose, insulin resistance and aberrant glucose output in lean mice. Taken together, we identify a MAFG-lncRNA axis controlling hepatic glucose metabolism in health and metabolic disease

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Practical Application of the 3Rs in Rodent Transgenesis

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    The principles of the 3Rs (replace, reduce, refine), as originally published by Russell and Burch, are internationally acclaimed guidelines for meeting ethical and welfare standards in animal experimentation. Genome manipulation is a standard technique in biomedical research and beyond. The goal of this chapter is to give practical advice on the implementation of the 3Rs in laboratories generating genetically modified rodents. We cover 3R aspects from the planning phase through operations of the transgenic unit to the final genome-manipulated animals. The focus of our chapter is on an easy-to-use, concise protocol that is close to a checklist. While we focus on mice, the proposed methodological concepts can be easily adapted for the manipulation of other sentient animals

    3R measures in facilities for the production of genetically modified rodents

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    Sociocultural changes in the human–animal relationship have led to increasing demands for animal welfare in biomedical research. The 3R concept is the basis for bringing this demand into practice: Replace animal experiments with alternatives where possible, Reduce the number of animals used to a scientifically justified minimum and Refine the procedure to minimize animal harm. The generation of gene-modified sentient animals such as mice and rats involves many steps that include various forms of manipulation. So far, no coherent analysis of the application of the 3Rs to gene manipulation has been performed. Here we provide guidelines from the Committee on Genetics and Breeding of Laboratory Animals of the German Society for Laboratory Animal Science to implement the 3Rs in every step during the generation of genetically modified animals. We provide recommendations for applying the 3Rs as well as success/intervention parameters for each step of the process, from experiment planning to choice of technology, harm–benefit analysis, husbandry conditions, management of genetically modified lines and actual procedures. We also discuss future challenges for animal welfare in the context of developing technologies. Taken together, we expect that our comprehensive analysis and our recommendations for the appropriate implementation of the 3Rs to technologies for genetic modifications of rodents will benefit scientists from a wide range of disciplines and will help to improve the welfare of a large number of laboratory animals worldwide

    3R Measures in facilities for the production of genetically modified rodents

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    Sociocultural changes in the human-animal relationship have led to increasing demands for animal welfare in biomedical research. The 3R concept is the basis for bringing this demand into practice: Replace animal experiments with alternatives where possible, Reduce the number of animals used to a scientifically justified minimum and Refine the procedure to minimize animal harm. The generation of gene-modified sentient animals such as mice and rats involves many steps that include various forms of manipulation. So far, no coherent analysis of the application of the 3Rs to gene manipulation has been performed. Here we provide guidelines from the Committee on Genetics and Breeding of Laboratory Animals of the German Society for Laboratory Animal Science to implement the 3Rs in every step during the generation of genetically modified animals. We provide recommendations for applying the 3Rs as well as success/intervention parameters for each step of the process, from experiment planning to choice of technology, harm-benefit analysis, husbandry conditions, management of genetically modified lines and actual procedures. We also discuss future challenges for animal welfare in the context of developing technologies. Taken together, we expect that our comprehensive analysis and our recommendations for the appropriate implementation of the 3Rs to technologies for genetic modifications of rodents will benefit scientists from a wide range of disciplines and will help to improve the welfare of a large number of laboratory animals worldwide
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