214 research outputs found
Identificatie en karakterisatie van genen en proteïnen in het actiemechanisme van 1,25-dihydroxyviatamin D3 in MC3T3-E1 muizen osteoblastcellen
No full textThe secosteroid hormone vitamin D3 was discovered as an essential nutrient for the prevention of rickets. The active form of vitamin D3, 1,25(OH)2D3, is indispensable to sustain calcium and phosphorus homeostasis and bone metabolism. These features, often summarized as the classical actions of 1,25(OH)2D3, are carefully balanced in a regulation circuit which involves the parathyroid hormone (PTH) as a main counterpart. The exact changes induced by 1,25(OH)2D3 in the gene expression program of bone cells are far from resolved and the identification of new vitamin D receptor (VDR) target genes will contribute to a better understanding of the influence of 1,25(OH)2D3 on bone. The first objective of this study was to investigate in more detail the effects of 1,25(OH)2D3 on the cystathionine ß-synthase gene, Cbs, in murine pre-osteoblastic MC3T3-E1 cells. In a microarray experiment on MC3T3-E1 cells, Cbs was first found to be highly and sustainably upregulated by 1,25(OH)2D3. Subsequent qRT-PCR experiments and Western blotting confirmed the increase of Cbs mRNA and higher CBS protein levels after 1,25(OH)2D3 treatment in murine MC3T3-E1 cells. The CBS protein is the initial enzyme of the transsulfuration pathway, a metabolic sequence necessary for irreversible homocysteine (HCY) breakdown and cysteine creation. Higher levels of CBS and increased enzymatic activity after 1,25(OH)2D3 treatment were accompanied by an enhanced consumption of intracellular HCY and an increase in cystathionine and cysteine levels which also affected the composition of the cell supernatant accordingly. The fact that 1,25(OH)2D3 is able to alter Cbs expression not only in MC3T3-E1 cells stressed the general nature of this finding. Furthermore, the study on the relationship between serum HCY and 25(OH)D3 levels in humans revealed a significant relationship between both parameters. The analysis showed that HCY levels reached a minimum when 25(OH)D3 levels were around 50 nM (20 ng/mL). Cbs transcription is directly transcriptionally controlled by VDR which was suggested by decreased Cbs expression in primary Vdr knockout osteoblasts and later shown by ChIP-on-chip and subsequent transfection experiments. Computer-based analysis of the murine Cbs gene revealed the presence of a putative DR3-type 1,25(OH)2D3 responsive element (VDRE) within the second Cbs intron. The functionality of the newly identified VDR-binding site was proven by mutation analysis linked to transfection experiments. To conclude this part of the study, we demonstrated that HCY concentration and metabolism were connected to 1,25(OH)2D3 via the upregulation of the cystathione ß-synthase gene Cbs on bone. This may have implications for bone health since high HCY levels have detrimental effects on bone stability and are also associated with an increased risk of osteoporosis. A local decrease in HCY levels may therefore be beneficial for bone health even if the systemic HCY level is not or only slightly altered, which may be due to the unresponsiveness of hepatic HCY metabolism to 1,25(OH)2D3. <br>Our second aim was to obtain a better understanding of semaphorin (SEMA) signalling in bone cells. This was prompted by the observed upregulation of neuropilin 2 (Nrp2) and Sema3c expression seen in a microarray experiment performed on 1,25(OH)2D3-treated MC3T3-E1 cells. The different genes coding for the proteins of the SEMA3 signalling complex are involved in the regulation of developmental, regulatory, and pathological processes. Nevertheless, the exact function of most of these genes in bone-related processes is still unresolved. By using qRT-PCR, we determined the changes in gene expression after 1,25(OH)2D3 treatment. Additional ChIP-on-chip experiments suggested the binding of VDR and the retinoid X receptor (RXR) and the presence of acetylated histone 4 (H4-Ac) in the genomic regions of Sema3b, Sema3f, Nrp2, and plexin (Plxn) A1. In silico screening of these genes revealed the presence of DR3-type VDRE sites in their introns or promoters. Except from Sema3b, which was already suggested to be a direct VDR target, all the other genes had not yet been described to be under direct control of 1,25(OH)2D3. The functionality of the newly identified VDREs and their involvement in 1,25(OH)2D3-driven upregulation was furthermore confirmed by mutation analysis connected to reporter gene analysis. In addition, we demonstrated that almost all examined Sema3s, Nrps, Plxnas, and Plxnd1 had also a 1,25(OH)2D3-independent role in bone biology because of the strong changes in gene expression during osteoclastogenesis and mineralization. These findings stressed that SEMA3 signalling is also present in bone where it may influence processes essential for bone homeostasis, a finding that demands further detailed examination.The third aim of this study was to gain more insights into the changes that occur after 1,25(OH)2D3 treatment on the proteome level of MC3T3-E1 pre-osteoblasts. We used two dimensional fluorescence difference gel electrophoresis (2-D DIGE) and found that the observed alterations caused by 1,25(OH)2D3 were mostly seen after 24 h of treatment. By MALDI-TOF/TOF MS we were able to identify in total, 50 protein spots that accounted for 41 distinct proteins. Among these regulated proteins, most could be classified to categories that included proteins involved in cell cycle regulation, cytoskeletal adaptation but also to protein structure and modification, stress response, metabolism or transport and redox signalling. The most prominent proteins identified were procollagen-lysine,2-oxoglutarate 5-dioxygenase 2 isoform 2 (PLOD2), aldose reductase-related protein 2 (AKR1B8), and chloride intracellular channel protein 4 (CLIC4). Of interest to us, PLOD2 and AKR1B8 are necessary for collagen cross-linking and for advanced glycation end product (AGE) elimination and therefore necessary for bone health. Also CLIC4 may have implications for bone homeostasis since also other chloride channel proteins are known to be involved in bone homeostasis. From the identified proteins, five were also found to be regulated on the previously performed microarray experiment on MC3T3-E1 cells. From these proteins, three were downregulated [DNA replication licensing factor mini-chromosome maintenance 7 (MCM7), proliferating cell nuclear antigen (PCNA), and stathmin (STMN1)] and two upregulated [purine nucleoside phosphorylase (PNP1) and CLIC4)]. This weak overlap is in accordance with the already described differences between transcriptome and proteome analysis and emphasizes the advantage to combine both kind of data sets, which complement each other and may help to get a more complete overview of the effects caused by 1,25(OH)2D3 treatment in bone cells.In general, this study contributed to a better understanding of the regulatory network of 1,25(OH)2D3 on osteoblasts. Moreover, the obtained data and findings unravel additional direct effects of 1,25(OH)2D3 on bone.status: Publishe
How to be a woman. Models of masochism and sacrifice in young adult fiction
No full textBuffy, Bella, Veronica, Katniss, Clary, Tris and Saba : For two decades post-feminist heroines have faced life-threatening trials as part of their progress to womanhood. In this chapter I consider how young adult popular fictions operate as forms of pedagogy for young women by offering them particular models of maturity and womanhood. I explore the recurrence and reformulation of a persistent pattern of behaviour in which heroines engage in risky and/or masochistic behaviours for which they are emotionally rewarded.. These recurrences function as a form of vicarious experiential learning in which readers and viewers learn that emotional gratification and adult status are conferred through self-harm and self-sacrifice. Popular culture is not a monolithic form and young adult fictions are no exception. An analysis of fictional examples of this behaviour pattern challenges the idea that heroines today are empowered agents as a result of the legacy of feminism. At the same time, the analysis belies any notion that fictions are universally hegemonic and oppressive – fictions can and do disrupt and interrogate this pattern of emotional masochism. Scholars of public pedagogy have explored the complexities, contradictions and subtleties of the pedagogical process. Sandlin O’Malley and Burdick (2011) in their review of public pedagogy literature acknowledge that some scholarship has demonstrated how “the teaching and learning inherent within daily life can be both oppressive and resistant” (p. 144). Jubas and Knutson (2012) also see public pedagogy as an arena where contradictions and tensions are in play. They argue that we can see “New examples of dialectic or tensions … between the authority of the producer and the consumer; between traditional structures which ground identities and help people make sense of cultural texts, and personal agency which frees people to choose and invent identities and meanings” (p. 86). This analysis aims to contribute to understandings of the complexities of public pedagogy by showing how fictions aimed primarily at young women both resist and accommodate patriarchy
Sensory overload in a shopping environment: Not every sensory modality leads to too much stimulation
No full textRetailers use atmospheric cues to trigger emotional reactions that enhance consumer behavior. However, introducing cues into a store environment may also trigger sensory overload, due to too much stimulation. This study aims to examine the effects of adding high arousal atmospheric cues in a store environment on affective reactions, approach behavior, and evaluations by making use of different methods (i.e., two lab experiments and one field experiment), by adding various types of atmospheric cues (i.e., cues processed in higher senses versus processed in lower senses), and by differentiating the order in which they are added. Results reveal that when a third high arousal cue is added sensory overload (i.e., rise in perceived arousal and decrease in perceived pleasantness) occurs under the condition that this third cue is processed by a higher sense (i.e. visual or auditory sense). Furthermore, a decrease in approach behavior and evaluations is also observed when these conditions are met. Mediation analyses indicate that this effect on evaluations is mediated by pleasure and approach behavior. The research presented extends previous findings by investigating possible predictors (i.e., number of cues as well as type of cues) of the momentum where sensory overload may take place.Douce, L (corresponding author), Hasselt Univ, Fac Business Econ, Dept Mkt & Strategy, Campus Diepenbeek,Agoralaan Bldg D, BE-3590 Diepenbeek, Belgium.
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Plutarch's practical ethics: the social dynamics of philosophy
No full textThe Second Sophistic (c.AD 60-250) was a time of intense competition for honour and status. Like today, this often caused mental as well as physical stress for the elite of the Roman Empire. This book, which transcends the boundaries between literature, social history, and philosophy, studies Plutarch's practical ethics, a group of twenty-odd texts within the Moralia designed to help powerful Greeks and Romans manage their ambitions and society's expectations successfully. Lieve Van Hoof combines a systematic analysis of the general principles underlying Plutarch's practical ethics, including the author's target readership, therapeutical practices, and self-presentation, with five innovative case studies. A picture emerges of philosophy under the Roman Empire not as a set of abstract, theoretical doctrines, but as a kind of symbolic capital engendering power and prestige for author and reader alike
Design, Synthesis, and Biological Evaluation of New Type of Gemini Analogues with a Cyclopropane Moiety in Their Side Chain
No full textImpact Factor: - 2023 (2024 update): 6.8Fil: Gómez-Bouzó, Uxía. Universidad de Vigo. Departamento de Química Orgánica and Instituto de Investigación Sanitaría Galicia; Spain.Fil: Peluso-Iltis Carole. Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch; France.Fil: Peluso-Iltis Carole. CNRS UMR 7104, Illkirch; France.Fil: Peluso-Iltis Carole. Inserm U1258, Illkirch; France.Fil: Peluso-Iltis Carole. University of Strasbourg, Illkirch; France.Fil: Santalla, Hugo. Universidad de Vigo. Departamento de Química Orgánica and Instituto de Investigación Sanitaría Galicia; Spain.Fil: Quevedo, Mario Alfredo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Ciencias Farmacéuticas; Argentina.Fil: Quevedo, Mario Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y desarrollo en Tecnología Farmacéutica; Argentina.Fil. Verlinden, Lieve. Clinical and Experimental Endocrinology: Department of Chronic Diseases and Metabolism, Leuven; Belgium.Fil: Verstuyf, Annemieke. Clinical and Experimental Endocrinology: Department of Chronic Diseases and Metabolism, Leuven; Belgium.Fil: Fall, Yagamare. Universidad de Vigo. Departamento de Química Orgánica and Instituto de Investigación Sanitaría Galicia; Spain.Fil: Gómez, Generosa. Universidad de Vigo. Departamento de Química Orgánica and Instituto de Investigación Sanitaría Galicia; Spain.Fil: Rochel, Natacha. Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch; France.Fil: Rochel, Natacha. CNRS UMR 7104, Illkirch; France.Fil: Rochel, Natacha. Inserm U1258, Illkirch; France.Fil: Rochel, Natacha. University of Strasbourg, Illkirch; France.We synthesized two new gemini analogues, UG-480 and UG-481, that incorporate a modified longer side chain containing a cyclopropane group. The evaluation of the bioactivities of the two gemini analogues indicated that the 17,20 threo (20S) compound, UG-480, is the most active one and is as active as 1,25(OH)2D3. Docking and molecular dynamics (MD) data showed that the compounds bind efficiently to vitamin D receptor (VDR) with UG-480 to form an energetically more favorable interaction with His397. Structural analysis indicated that whereas the UG-480 compound efficiently stabilizes the active VDR conformation, it induces conformational changes in the H6–H7 VDR region that are greater than those induced by the parental Gemini and that this is due to the occupancy of the secondary channel by its modified side chain.info:eu-repo/semantics/publishedVersionFil: Gómez-Bouzó, Uxía. Universidad de Vigo. Departamento de Química Orgánica and Instituto de Investigación Sanitaría Galicia; Spain.Fil: Peluso-Iltis Carole. Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch; France.Fil: Peluso-Iltis Carole. CNRS UMR 7104, Illkirch; France.Fil: Peluso-Iltis Carole. Inserm U1258, Illkirch; France.Fil: Peluso-Iltis Carole. University of Strasbourg, Illkirch; France.Fil: Santalla, Hugo. Universidad de Vigo. Departamento de Química Orgánica and Instituto de Investigación Sanitaría Galicia; Spain.Fil: Quevedo, Mario Alfredo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Ciencias Farmacéuticas; Argentina.Fil: Quevedo, Mario Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y desarrollo en Tecnología Farmacéutica; Argentina.Fil. Verlinden, Lieve. Clinical and Experimental Endocrinology: Department of Chronic Diseases and Metabolism, Leuven; Belgium.Fil: Verstuyf, Annemieke. Clinical and Experimental Endocrinology: Department of Chronic Diseases and Metabolism, Leuven; Belgium.Fil: Fall, Yagamare. Universidad de Vigo. Departamento de Química Orgánica and Instituto de Investigación Sanitaría Galicia; Spain.Fil: Gómez, Generosa. Universidad de Vigo. Departamento de Química Orgánica and Instituto de Investigación Sanitaría Galicia; Spain.Fil: Rochel, Natacha. Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch; France.Fil: Rochel, Natacha. CNRS UMR 7104, Illkirch; France.Fil: Rochel, Natacha. Inserm U1258, Illkirch; France.Fil: Rochel, Natacha. University of Strasbourg, Illkirch; France
Synthesis, structure, and biological activity of des-side Chain analogues of 1α,25-Dihydroxyvitamin D3 with substituents at C18
No full textAn improved synthetic route to 1α,25-dihydroxyvitamin D3 des-side chain analogues 2a and 2b with substituents at C18 is reported, along with their biological activity. These analogues display significant antiproliferative effects toward MCF-7 breast cancer cells and prodifferentiation activity toward SW480-ADH colon cancer cells; they are also characterized by a greatly decreased calcemic profile. The crystal structure of the human vitaminD receptor (hVDR) complexed to one of these analogues, 20(17→18)-abeo-1α,25-dihydroxy-22-homo-21-norvitamin D3 (2a) reveals that the side chain introduced at position C18 adopts the same orientation in the ligand binding pocket as the side chain of 1α,25-dihydroxyvitamin D3. Vitamin D3 supplements: The synthesis and biological activity of des-side chain analogues of 1α,25-dihydroxyvitamin D3 with substituents at C18 are described. Crystallographic analysis revealed that the new side chain introduced at C18 adopts the same orientation as the natural side chain at C17 in the parent molecule 1α,25-dihydroxyvitamin D3. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Fil: Verlinden, Lieve. Katholikie Universiteit Leuven; BélgicaFil: Verstuyf, Annemieke. Katholikie Universiteit Leuven; BélgicaFil: Eelen, Guy. Katholikie Universiteit Leuven; BélgicaFil: Bouillon, Roger. Katholikie Universiteit Leuven; BélgicaFil: Ordóñez-Morán, Paloma. Universidad Autónoma de Madrid; EspañaFil: Larriba, María Jesús. Universidad Autónoma de Madrid; EspañaFil: Muñoz, Alberto. Universidad Autónoma de Madrid; EspañaFil: Rochel, Natacha. Université de Strasbourg; FranciaFil: Sato, Yoshiteru. Université de Strasbourg; FranciaFil: Moras, Dino. Université de Strasbourg; FranciaFil: Maestro, Miguel. Universidad da Coruña; EspañaFil: Seoane, Samuel. Universidad de Santiago de Compostela, Facultad de Medicina;Fil: Dominguez, Fernando. Universidad de Santiago de Compostela, Facultad de Medicina;Fil: Eduardo, Silvina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Santiago de Compostela; EspañaFil: Nicoletti, Daniel. Universidad de Santiago de Compostela; EspañaFil: Moman, Edelmiro. Universidad de Santiago de Compostela; EspañaFil: Mouriño, Antonio. Universidad de Santiago de Compostela; Españ
The future of vitamin D analogs
No full textThe active form of vitamin D3, 1,25-dihydroxyvitamin D3, is a major regulator of bone and calcium homeostasis. In addition, this hormone also inhibits the proliferation and stimulates the differentiation of normal as well as malignant cells. Supraphysiological doses of 1,25-dihydroxyvitamin D3 are required to reduce cancer cell proliferation. However, these doses will lead in vivo to calcemic side effects such as hypercalcemia and hypercalciuria. During the last 25 years, many structural analogs of 1,25-dihydroxyvitamin D3 have been synthesized by the introduction of chemical modifications in the A-ring, central CD-ring region or side chain of 1,25-dihydroxyvitamin D3 in the hope to find molecules with a clear dissociation between the beneficial antiproliferative effects and adverse calcemic side effects. One example of such an analog with a good dissociation ratio is calcipotriol (DaivonexR), which is clinically used to treat the hyperproliferative skin disease psoriasis. Other vitamin D analogs were clinically approved for the treatment of osteoporosis or secondary hyperparathyroidism. No vitamin D analog is currently used in the clinic for the treatment of cancer although several analogs have been shown to be potent drugs in animal models of cancer. Omics studies as well as in vitro cell biological experiments unraveled basic mechanisms involved in the antineoplastic effects of vitamin D and its analogs. 1,25-dihydroxyvitamin D3 and analogs act in a cell type- and tissue-specific manner. Moreover, a blockade in the transition of the G0/1 towards S phase of the cell cycle, induction of apoptosis, inhibition of migration and invasion of tumor cells together with effects on angiogenesis and inflammation have been implicated in the pleiotropic effects of 1,25-dihydroxyvitamin D3 and its analogs. In this review we will give an overview of the action of vitamin D analogs in tumor cells and look forward how these compounds could be introduced in the clinical practice
Semaphorin signaling in bone
No full textSemaphorin molecules regulate cell adhesion and motility in a wide variety of cell types and are therefore involved in numerous processes including axon guidance, angiogenesis, cardiogenesis, tumor growth, and immune response. Increasing evidence points to a role of transmembrane, membrane-associated and soluble semaphorins during bone development as well as in the control of normal bone homeostasis. Within bone, semaphorins are implicated in the communication between different cell types by relaying signals in an autocrine or paracrine way. Semaphorins are not only involved in bone resorption but also in bone formation. Therefore, targeting semaphorin-induced signaling in bone may constitute an interesting new therapeutic strategy in osteoporosis. However, all the pioneering research on semaphorins is performed in mice and it remains to be established to what extent semaphorin signaling pathways are conserved between mice and men. In addition, knowledge of semaphorin signaling in bone mostly arises from loss/gain of function studies of one single semaphorin and/or receptor. However, different semaphorin molecules are co-expressed in bone and their signaling pathways are likely to interact in a complex and coherent way that needs proper understanding before targeting semaphorin signaling can be therapeutically exploited.sponsorship: This work was supported by grants from the Fund for Scientific Research (FWO G.OA17.14N) and the KU Leuven (GOA/14/010). (KU Leuven|GOA/14/010, FWO G.OA17.14N)status: Publishe
Antineoplastic effects of 1,25(OH)2D3 and its analogs in breast, prostate and colorectal cancer
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