1,721,085 research outputs found
Roles of lysophosphatidic acid and sphingosine-1-phosphate in stem cell biology
No full textStem cells are unique in their ability to self-renew and differentiate into various cell types. Because of these features, stem cells are key to the formation of organisms and play fundamental roles in tissue regeneration and repair. Mechanisms controlling their fate are thus fundamental to the development and homeostasis of tissues and organs. Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are bioactive phospholipids that play a wide range of roles in multiple cell types, during developmental and pathophysiological events. Considerable evidence now demonstrates the potent roles of LPA and S1P in the biology of pluripotent and adult stem cells, from maintenance to repair. Here we review their roles for each main category of stem cells and explore how those effects impact development and physiopathology.Grace E. Lidgerwood, Stuart M. Pitson, Claudine Bonder, Alice Péba
Sphingosine kinase 2 promotes acute lymphoblastic leukemia by enhancing MYC expression
No full textAbstract not availableCraig T. Wallington-Beddoe, Jason A. Powell, Daochen Tong, Stuart M. Pitson, Kenneth F. Bradstock and Linda J. Bendal
Tumor necrosis factor-induced neutrophil adhesion occurs via sphingosine kinase-1-dependent activation of endothelial alpha(5)beta(1) integrin
No full textLeukocyte recruitment plays a major role in the immune response to infectious pathogens, as well as during inflammatory and autoimmune disorders. The process of leukocyte extravasation from the blood requires a complex cascade of adhesive events between the leukocytes and the endothelium, including initial leukocyte rolling, adhesion, and finally transendothelial migration. Current research in this area aims to identify the key leukocyte subsets that initiate a given disease and to identify the trafficking molecule(s) that will most specifically inhibit those cells. Herein we demonstrate that tumor necrosis factor (TNF)α activates the integrin α5β1 without altering total expression levels of β1 integrin on human umbilical vein endothelial cells. Moreover, our studies suggest that TNFα-induced β1 activation is dependent on sphingosine kinase-1, but independent of the sphingosine-1-phosphate family of G protein-coupled receptors. We also show, using a parallel plate flow chamber assay, that neutrophil adhesion to TNFα-activated endothelium can be attenuated by blocking α5β1 or its ligand angiopoietin-2. These observations add new complexities that broaden the accepted concept of cellular trafficking with neutrophil adhesion to TNFα activated endothelial cells being sphingosine kinase-1, α5β1, and angiopoietin-2 dependent. Moreover, this work supports the notion that sphingosine kinase-1 may be the single target required for an effective broad spectrum approach to combat inflammation and immune disorders.Wai Y. Sun, Stuart M. Pitson and Claudine S. Bonde
Sphingolipid imbalance and inflammatory effects induced by uremic toxins in heart and kidney cells are reversed by dihydroceramide desaturase 1 inhibition
No full textAbstract not availableFeby Saviraa, Ruth Magayea, Carmen V. Scullinoc, Bernard L. Flynn, Stuart M. Pitson, Dovile Anderson, Darren J. Creek, Yue Hua, Xin Xionga, Li Huanga, Danny Liew, Christopher Reid, David Kaye, Andrew R. Kompah, Bing Hui Wan
Identification of sphingosine kinase 1 as a therapeutic target in B-lineage acute lymphoblastic leukaemia
No full textLink to a related website: https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/bjh.15097, Open Access via UnpaywallAbstract not availableCraig T. Wallington‐Beddoe, Vicki Xie, Daochen Tong, Jason A. Powell, Alexander C. Lewis, Lorena Davies, Stuart M. Pitson, Kenneth F. Bradstock
Linda J. Bendal
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A proinflammatory role for proteolytically cleaved annexin A1 in neutrophil transendothelial migration
Full text linkData source: Supplementary data, https://doi.org/10.4049/jimmunol.1000119
Link to a related website: https://www.jimmunol.org/content/jimmunol/185/5/3057.full.pdf, Open Access via UnpaywallNeutrophil extravasation, a critical component of innate immunity must be tightly regulated to prevent inadvertent or prolonged inflammation and subsequent tissue damage. We have shown previously that endothelial ERK1/2 signaling essential for neutrophil transendothelial migration is induced by a soluble factor produced by activated neutrophils. In this study, we demonstrate that the soluble neutrophil factor is a truncated form of annexin A1 (AnxA1) that can be generated by calpain 1 cleavage of the N terminus, thus identifying a novel proinflammatory function to AnxA1. In contrast, neither the full-length protein nor the N-terminal 26 aa peptide, previously shown to be antiinflammatory, were able to activate Erk. Our data suggest that two different fragments of AnxA1 have opposing functions in inflammation. We also provide evidence that C-terminal AnxA1 functions by increasing ICAM1 clustering around adherent neutrophils to anchor them to the endothelium and promote transmigration through the transcellular route.Samantha L. Williams, Ian R. Milne, Christopher J. Bagley, Jennifer R. Gamble, Mathew A. Vadas, Stuart M. Pitson, and Yeesim Khew-Goodal
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