101 research outputs found

    PPAR_2 expression in growth plate chondrocytes is regulated by p38 and GSK-3

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    Although peroxisome proliferator activated receptor (PPAR)_ remains a critical regulator of preadipocyte differentiation, new roles have been discovered in inflammation, bone morphogenesis, endothelial function, cancer, longevity and atherosclerosis. Despite the demonstration of PPAR expression in chondrocytes, its role and the pathways affecting its expression and activity in chondrocytes remain largely unknown. We investigated the effects of PPAR activation on chondrocyte differentiation and its participation in chondrocyte lipid metabolism. PPAR2 expression is highly regulated during chondrocyte differentiation in vivo and in vitro PPAR activation with troglitazone resulted in increased Indian hedgehog expression and reduced collagen X expression, confirming previously described roles in the inhibition of differentiation. However, the major effect of PPAR2 in chondrocytes appears to be on lipid metabolism. During differentiation chondrocytes increase expression of the lipid-associated metabolizing protein, Lpl, which is accompanied by increased gene expression of PPAR. PPAR expression is suppressed by p38 activity, but requires GSK-3 activity. Furthermore, Lpl expression is regulated by p38 and GSK-3 signalling. This is the first study demonstrating a relationship between PPAR2 expression and chondrocyte lipid metabolism and its regulation by p38 and GSK-3 signalling

    A Comprehensive Molecular Interaction Map for Rheumatoid Arthritis

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    Computational biology contributes to a variety of areas related to life sciences and, due to the growing impact of translational medicine - the scientific approach to medicine in tight relation with basic science -, it is becoming an important player in clinical-related areas. In this study, we use computation methods in order to improve our understanding of the complex interactions that occur between molecules related to Rheumatoid Arthritis (RA).Due to the complexity of the disease and the numerous molecular players involved, we devised a method to construct a systemic network of interactions of the processes ongoing in patients affected by RA. The network is based on high-throughput data, refined semi-automatically with carefully curated literature-based information. This global network has then been topologically analysed, as a whole and tissue-specifically, in order to translate the experimental molecular connections into topological motifs meaningful in the identification of tissue-specific markers and targets in the diagnosis, and possibly in the therapy, of RA.’

    Agouti C57BL/6N embryonic stem cells for mouse genetic resources.

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    We report the characterization of a highly germline competent C57BL/6N mouse embryonic stem cell line, JM8. To simplify breeding schemes, the dominant agouti coat color gene was restored in JM8 cells by targeted repair of the C57BL/6 nonagouti mutation. These cells provide a robust foundation for large-scale mouse knockout programs that aim to provide a public resource of targeted mutations in the C57BL/6 genetic background

    Mosaic expression of Atrx in the mouse central nervous system causes memory deficits

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    The rapid modulation of chromatin organization is thought to play a crucial role in cognitive processes such as memory consolidation. This is supported in part by the dysregulation of many chromatin-remodelling proteins in neurodevelopmental and psychiatric disorders. A key example is ATRX, an X-linked gene commonly mutated in individuals with syndromic and nonsyndromic intellectual disability. The consequences of Atrx inactivation for learning and memory have been difficult to evaluate because of the early lethality of hemizygous-null animals. In this study, we evaluated the outcome of brain-specific Atrx deletion in heterozygous female mice. These mice exhibit a mosaic pattern of ATRX protein expression in the central nervous system attributable to the location of the gene on the X chromosome. Although the hemizygous male mice die soon after birth, heterozygous females survive to adulthood. Body growth is stunted in these animals, and they have low circulating concentrations of insulin growth factor 1. In addition, they are impaired in spatial, contextual fear and novel object recognition memory. Our findings demonstrate that mosaic loss of ATRX expression in the central nervous system leads to endocrine defects and decreased body size and has a negative impact on learning and memory

    Quantification of joint blood flow by dynamic contrast-enhanced near-infrared spectroscopy: Application to monitoring disease activity in a rat model of rheumatoid arthritis

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    © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. Significance: Current guidelines for rheumatoid arthritis (RA) management recommend early treatment with disease modifying antirheumatic drugs (DMARDs). However, DMARD treatment fails in 30% of patients and current monitoring methods can only detect failure after 3 to 6 months of therapy. Aim: We investigated whether joint blood flow (BF), quantified using dynamic contrast-enhanced time-resolved near-infrared spectroscopy, can monitor disease activity and treatment response in a rat model of RA. Approach: Ankle joint BF was measured every 5 days in eight rats with adjuvant-induced arthritis (AIA) and four healthy controls. Arthritis was allowed to progress for 20 days before rats with AIA were treated with a DMARD once every 5 days until day 40. Results: Time and group had separate significant main effects on joint BF; however, there was no significant interaction between time and group despite a notable difference in average joint BF on day 5. Comparison of individual blood flow measures between rats with AIA and control group animals did not reveal a clear response to treatment. Conclusions: Joint BF time courses could not distinguish between rats with AIA and study controls. Heterogeneous disease response and low temporal frequency of BF measurements may have been important study limitations

    Efficient Designer Nuclease-Based Homologous Recombination Enables Direct PCR Screening for Footprintless Targeted Human Pluripotent Stem Cells

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    SummaryGenetic engineering of human induced pluripotent stem cells (hiPSCs) via customized designer nucleases has been shown to be significantly more efficient than conventional gene targeting, but still typically depends on the introduction of additional genetic selection elements. In our study, we demonstrate the efficient nonviral and selection-independent gene targeting in human pluripotent stem cells (hPSCs). Our high efficiencies of up to 1.6% of gene-targeted hiPSCs, accompanied by a low background of randomly inserted transgenes, eliminated the need for antibiotic or fluorescence-activated cell sorting selection, and allowed the use of short donor oligonucleotides for footprintless gene editing. Gene-targeted hiPSC clones were established simply by direct PCR screening. This optimized approach allows targeted transgene integration into safe harbor sites for more predictable and robust expression and enables the straightforward generation of disease-corrected, patient-derived iPSC lines for research purposes and, ultimately, for future clinical applications

    Primate iPS cells as tools for evolutionary analyses

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    Induced pluripotent stem cells (iPSCs) are regarded as a central tool to understand human biology in health and disease. Similarly, iPSCs from non-human primates should be a central tool to understand human evolution, in particular for assessing the conservation of regulatory networks in iPSC models. Here, we have generated human, gorilla, bonobo and cynomolgus monkey iPSCs and assess their usefulness in such a framework. We show that these cells are well comparable in their differentiation potential and are generally similar to human, cynomolgus and rhesus monkey embryonic stem cells (ESCs). RNA sequencing reveals that expression differences among clones, individuals and stem cell type are all of very similar magnitude within a species. In contrast, expression differences between closely related primate species are three times larger and most genes show significant expression differences among the analyzed species. However, pseudogenes differ more than twice as much, suggesting that evolution of expression levels in primate stem cells is rapid, but constrained. These patterns in pluripotent stem cells are comparable to those found in other tissues except testis. Hence, primate iPSCs reveal insights into general primate gene expression evolution and should provide a rich source to identify conserved and species-specific gene expression patterns for cellular phenotypes

    A forward genetic screen with a thalamocortical axon reporter mouse yields novel neurodevelopment mutants and a distinct emx2 mutant phenotype

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    <p>Abstract</p> <p>Background</p> <p>The dorsal thalamus acts as a gateway and modulator for information going to and from the cerebral cortex. This activity requires the formation of reciprocal topographic axon connections between thalamus and cortex. The axons grow along a complex multistep pathway, making sharp turns, crossing expression boundaries, and encountering intermediate targets. However, the cellular and molecular components mediating these steps remain poorly understood.</p> <p>Results</p> <p>To further elucidate the development of the thalamocortical system, we first created a thalamocortical axon reporter line to use as a genetic tool for sensitive analysis of mutant mouse phenotypes. The TCA-<it>tau-lacZ </it>reporter mouse shows specific, robust, and reproducible labeling of thalamocortical axons (TCAs), but not the overlapping corticothalamic axons, during development. Moreover, it readily reveals TCA pathfinding abnormalities in known cortical mutants such as <it>reeler</it>. Next, we performed an unbiased screen for genes involved in thalamocortical development using random mutagenesis with the TCA reporter. Six independent mutant lines show aberrant TCA phenotypes at different steps of the pathway. These include ventral misrouting, overfasciculation, stalling at the corticostriatal boundary, and invasion of ectopic cortical cell clusters. An outcross breeding strategy coupled with a genomic panel of single nucleotide polymorphisms facilitated genetic mapping with small numbers of mutant mice. We mapped a ventral misrouting mutant to the <it>Emx2 </it>gene, and discovered that some TCAs extend to the olfactory bulbs in this mutant. Mapping data suggest that other lines carry mutations in genes not previously known for roles in thalamocortical development.</p> <p>Conclusions</p> <p>These data demonstrate the feasibility of a forward genetic approach to understanding mammalian brain morphogenesis and wiring. A robust axonal reporter enabled sensitive analysis of a specific axon tract inside the mouse brain, identifying mutant phenotypes at multiple steps of the pathway, and revealing a new aspect of the <it>Emx2 </it>mutant. The phenotypes highlight vulnerable choice points and latent tendencies of TCAs, and will lead to a refined understanding of the elements and interactions required to form the thalamocortical system.</p> <p>See Commentary: <url>http://www.biomedcentral.com/1741-7007/9/1</url></p

    Female Barrenness, Bodily Access and Aromatic Treatments in Seventeenth-Century England

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    This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, CC BY-NC-ND 3.0 which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made, see https://creativecommons.org/licenses/by-nc-nd/3.0/.Scholars examining medical practice in early modern England have often remarked upon the complexities of the relationship between male physicians and female patients. It has been noted that ideas of female modesty and concern about the potential erotic nature of contact between patients and practitioners could affect the treatment of certain disorders. This paper contributes to this on-going discussion by examining the use of pungent substances to diagnose and treat female barrenness. Diagnostic tests included in medical treatises could rely upon the woman’s ability to perceive a particular substance. These tests thus put women at the centre of the diagnosis of their disorders and allowed them to negotiate access to their reproductive bodies. Similarly medical practitioners included a range of treatments for infertility that involved the fumes of certain substances entering the womb or surrounding the body. These treatments may have allowed women, and perhaps their medical practitioners, to choose a method of remedy that did not involve the application of external lotions to the genitalia. Thus by considering the multi-sensory nature of medical treatment this paper will highlight that the diversity of remedies advocated in early modern medical texts would perhaps have allowed women to restrict access to their reproductive bodies, while still obtaining diagnosis and treatment.Peer reviewe
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