Autophagy, tissue repair, and fibrosis: a delicate balance

Tissue repair and fibrosis, an abnormal form of repair, occur in most human organs in response to injury or inflammation. Fibroblasts play a major role in the normal repair process by differentiating into myofibroblasts that synthesize extracellular matrix (ECM) components and favor tissue remodeling to reestablish normal function and integrity. However, their persistent accumulation at the site of injury is a hallmark of fibrosis. Autophagy is a catabolic process that occurs in eukaryotic cells as a stress response to allow cell survival and maintenance of cellular homeostasis by degrading and recycling intracellular components. Recent advances identify autophagy as an important regulator of myofibroblast differentiation, tissue remodeling, and fibrogenesis. In this mini-review, we provide an overview of the interactions between autophagy, ECM, and fibrosis, and emphasize the molecular mechanisms involved in myofibroblast differentiation. We also describe the emerging concept of secretory autophagy as a new avenue for intercellular communication at the site of tissue injury and repair

Analyse documentaire en milieu universitaire : deux approches générales comparées

Ce mémoire porte sur l’analyse documentaire en milieu universitaire. Deux approches générales sont d’abord étudiées : l’approche centrée sur le document (premier chapitre), prédominante dans la tradition bibliothéconomique, et l’approche centrée sur l’usager (deuxième chapitre), influencée par le développement d’outils le plus souvent associés au Web 2.0. L’opposition entre ces deux démarches reflète une dichotomie qui se trouve au cœur de la notion de sujet, c’est-à-dire les dimensions objective et subjective du sujet. Ce mémoire prend par conséquent la forme d’une dissertation dont l’avantage principal est de considérer à la fois d’importants acquis qui appartiennent à la tradition bibliothéconomique, à la fois des développements plus récents ayant un impact important sur l’évolution de l’analyse documentaire en milieu universitaire. Notre hypothèse est que ces deux tendances générales doivent être mises en relief afin d’approfondir la problématique de l’appariement, laquelle définit la difficulté d’accorder le vocabulaire qu’utilise l’usager dans ses recherches documentaires avec celui issu de l’analyse documentaire (métadonnées sujet). Dans le troisième chapitre, nous examinons certaines particularités liées à l’utilisation de la documentation en milieu universitaire dans le but de repérer certaines possibilités et certaines exigences de l’analyse documentaire dans un tel milieu. À partir d’éléments basés sur l’analyse des domaines d’études et sur la démarche analytico-synthétique, il s’agit d’accentuer l’interaction potentielle entre usagers et analystes documentaires sur le plan du vocabulaire utilisé de part et d’autre.The topic of this dissertation is subject analysis in a university environment. Two major approaches are studied at first: subject analysis centered on the document (first chapter), historically predominant in librarianship, and subject analysis centered on the user (second chapter), mostly influenced by the development of Web 2.0 technologies. The opposition between those two approaches reflects a dichotomy which is at the very heart of the notion of subject, meaning the objective and subjective aspects of the subject. The outline of the dissertation has the distinct advantage of presenting well established practices in the field of librarianship as well as recent developments that do have an impact on subject analysis in a university environment. Our hypothesis is that both major tendencies must be highlighted to study the question of mapping the terminology (subject metadata) that comes from subject analysis with the terminology that users tend to favor while searching for documents. In the third chapter, we examine more closely particularities of the university environment in an effort to look at distinct possibilities and requirements for subject analysis in such an environment. Reinforced by elements taken from domain and facet analysis, the goal is to accentuate the potential interaction between users and indexers on a terminological level

Community pharmacists' involvement in research in the United Kingdom

Puropse. To investigate the engagement of community pharmacists (CPs) with pharmacy research and identify barriers preventing them from doing so. In addition, to determine the training and research tools available to support CPs to take part in research. Methods. A questionnaire was designed and distributed to a sample of community pharmacies (n = 323) within five local authorities in England, and to a random sample of community pharmacies (n = 329) within Greater London in two stages. Descriptive statistics were used to analyse the data using Microsoft Excel. Following questionnaire completion, CPs were invited to take part in face-to-face and telephone interviews to further explore their views on research. Interviews were transcribed and analysed using coding and thematic analysis. Results. A total of 104 questionnaires were completed out of 652 distributed. Over half (56.7%) of respondents considered research to be important to their practice. Approximately 88% of respondents had completed some form of mandatory research in the past two years, while only 29% were involved in non-mandatory research. Over two-thirds (67.9%) wanted to engage with research in the future, with 22.2% of these being most interested in recruiting patients for research. Barriers to research included lack of time (90%) and lack of remuneration (60%). 20 community pharmacists were interviewed. Three themes were identified: 1. Interest in taking part in research; 2. Awareness, support and knowledge; 3. Resources as barriers. Conclusion. CPs recognise the importance of research in their current practice, however, the biggest barrier they face is time. Further training may be useful to ensure CPs are adequately prepared to undertake research activities

Autophagy drives fibroblast senescence through MTORC2 regulation

Sustained macroautophagy/autophagy favors the differentiation of fibroblasts into myofibroblasts. Cellular senescence, another means of responding to long-term cellular stress, has also been linked to myofibroblast differentiation and fibrosis. Here, we evaluate the relationship between senescence and myofibroblast differentiation in the context of sustained autophagy. We analyzed markers of cell cycle arrest/senescence in fibroblasts in vitro, where autophagy was triggered by serum starvation (SS). Autophagic fibroblasts expressed the senescence biomarkers CDKN1A/p21 and CDKN2A/p16 and exhibited increased senescenceassociated GLB1/beta-galactosidase activity. Inhibition of autophagy in serum-starved fibroblasts with 3-methyladenine, LY294002, or ATG7 (autophagy related 7) silencing prevented the expression of senescence-associated markers. Similarly, suppressing MTORC2 activation using rapamycin or by silencing RICTOR also prevented senescence hallmarks. Immunofluorescence microscopy showed that senescence and myofibroblast differentiation were induced in different cells, suggesting mutually exclusive activation of senescence and myofibroblast differentiation. Reactive oxygen species (ROS) are known inducers of senescence and exposing fibroblasts to ROS scavengers decreased ROS production during SS, inhibited autophagy, and significantly reduced the expression of senescence and myofibroblast differentiation markers. ROS scavengers also curbed the AKT1 phosphorylation at Ser473, an MTORC2 target, establishing the importance of ROS in fuelling MTORC2 activation. Inhibition of senescence by shRNA to TP53/p53 and shRNA CDKN2A/p16 increased myofibroblast differentiation, suggesting a negative feedback loop of senescence on autophagy-induced myofibroblast differentiation. Collectively, our results identify ROS as central inducers of MTORC2 activation during chronic autophagy, which in turn fuels senescence activation and myofibroblast differentiation in distinct cellular subpopulations

Evidence-based selection of theories for designing behaviour change interventions : using methods based on theoretical construct domains to understand clinicians' blood transfusion behaviour

Peer reviewedPostprin

Autolysosomes and caspase-3 control the biogenesis and release of immunogenic apoptotic exosomes

Apoptotic exosome-like vesicles (ApoExos) are a novel type of extracellular vesicle that contribute to the propagation of inflammation at sites of vascular injury when released by dying cells. ApoExos are characterized by the presence of the C-terminal perlecan LG3 fragment and 20S proteasome, and they are produced downstream of caspase-3 activation. In the present study, we assessed the relative roles of autophagy and caspase-3-mediated pathways in controlling the biogenesis and secretion of immunogenic ApoExos. Using electron microscopy and confocal immunofluorescence microscopy in serum-starved endothelial cells, we identified large autolysosomes resulting from the fusion of lysosomes, multivesicular bodies, and autophagosomes as a site of ApoExo biogenesis. Inhibition of autophagy with ATG7 siRNA or biochemical inhibitors (wortmannin and bafilomycin) coupled with proteomics analysis showed that autophagy regulated the processing of perlecan into LG3 and its loading onto ApoExos but was dispensable for ApoExo biogenesis. Caspase-3 activation was identified using caspase-3-deficient endothelial cells or caspase inhibitors as a pivotal regulator of fusion events between autolysosomes and the cell membrane, therefore regulating the release of immunogenic ApoExos. Collectively, these findings identified autolysosomes as a site of ApoExo biogenesis and caspase-3 as a crucial regulator of autolysosome cell membrane interactions involved in the secretion of immunogenic ApoExos

Using theories of behaviour to understand transfusion prescribing in three clinical contexts in two countries: Development work for an implementation trial

<p>Abstract</p> <p>Background</p> <p>Blood transfusion is an essential part of healthcare and can improve patient outcomes. However, like most therapies, it is also associated with significant clinical risks. In addition, there is some evidence of overuse. Understanding the potential barriers and enablers to reduced prescribing of blood products will facilitate the selection of intervention components likely to be effective, thereby reducing the number of costly trials evaluating different implementation strategies. Using a theoretical basis to understand behaviours targeted for change will contribute to a 'basic science' relating to determinants of professional behaviour and how these inform the selection of techniques for changing behaviour. However, it is not clear which theories of behaviour are relevant to clinicians' transfusing behaviour. The aim of this study is to use a theoretical domains framework to identify relevant theories, and to use these theories to identify factors that predict the decision to transfuse.</p> <p>Methods</p> <p>The study involves two steps: interview study and questionnaire study. Using a previously identified framework, we will conduct semi-structured interviews with clinicians to elicit their views about which factors are associated with waiting and further monitoring the patient rather than transfusing red blood cells. Interviews will cover the following theoretical domains: knowledge; skills; social/professional role and identity; beliefs about capabilities; beliefs about consequences; motivation and goals; memory, attention, and decision processes; environmental context and resources; social influences; emotion; behavioural regulation; nature of the behaviour. The interviews will take place independently in Canada and the UK and involve two groups of physicians in each country (UK: adult and neonatal intensive care physicians; Canada: intensive care physicians and orthopaedic surgeons). We will: analyse interview transcript content to select relevant theoretical domains; use consensus processes to map these domains on to theories of behaviour; develop questionnaires based on these theories; and mail them to each group of physicians in the two countries. From our previous work, it is likely that the theories will include: theory of planned behaviour, social cognitive theory and the evidence-based strategy, implementation intention. The questionnaire data will measure predictor variables (theoretical constructs) and outcome variables (intention and clinical decision), and will be analysed using multiple regression analysis. We aim to achieve 150 respondents in each of the four groups for each postal survey.</p

Analysis of satellite gravity and bathymetry data over Ninety-East Ridge: Variation in the compensation mechanism and implication for emplacement process

International audienceWe investigate the mode of compensation, emplacement history and deep density structure of the Ninety-East Ridge (Indian Ocean) using spectral analyses and forward modeling of satellite gravity and bathymetry data. We find that the northern (0–10°N) and the southern (20–30°S) parts of the ridge are flexurally compensated with an effective elastic thickness >15 km, whereas the central part (0–20°S) is locally compensated. Furthermore, we find that for a part of central block (10–20°S, over Osborn Knoll) the compensation depth is unreasonably very high (30–40 km). Therefore we favor a model with subsurface loading and interpret this to be due to underplating of mafic material at the base of the crust, a hypothesis that is supported by seismic results and direct modeling of gravity data along some profiles. These results suggest that the northern and southern parts of Ninety-East Ridge were emplaced off to a ridge axis compared to the central one, which might have been emplaced on or near a spreading center. Locally compensated large topography, thick underplated crust in the central part (near Osborn Knoll), might result from an interaction of a hot spot with the extinct Wharton spreading ridge

Characterization of sills associated with the U reflection on the Newfoundland margin : evidence for widespread early post-rift magmatism on a magma-poor rifted margin

Author Posting. © The Authors, 2010. This article is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 182 (2010): 113-136, doi:10.1111/j.1365-246X.2010.04635.x.Drilling during ODP Leg 210 penetrated two post-rift sills (dated as ∼105.3 and ∼97.8 Ma) in the deep sediments overlying basement of the continent–ocean transition zone on the magma-poor Newfoundland margin. The sill emplacement post-dated the onset of seafloor spreading by at least 7–15 Myr. The shallower of the two sills coincides with the high-amplitude U reflection observed throughout the deep Newfoundland Basin, and strong reflectivity in the sub-U sequence suggests that a number of other sills are present there. In this paper, we use multichannel seismic reflection data and synthetic seismograms to investigate the nature, magnitude and extent of this post-rift magmatism in the deep basin. Features observed in seismic profiles that we attribute to sill injection include high-amplitude reflections with geometries characteristic of intrusions such as step-like aspect; abrupt endings, disruptions and junctions of reflections; finger-like forms; differential compaction around possible loci of magma injection and disruption of overlying sediments by apparent fluid venting. Interpreted sills occur only over transitional basement that probably consists of a mixture of serpentinized peridotite and highly thinned continental crust, and they cover an area of ∼80 000 km2. From analysis of synthetic seismograms, we estimate that sill intrusions may comprise ∼26 per cent of the sub-U high-reflectivity sequence, which yields a crude estimate of ∼5800 km3 for the total volume of sills emplaced by post-rift magmatism. This is significant for a margin usually described as 'non-volcanic'. We discuss competing hypotheses about the source of the magmatism, which is still uncertain.G. Peron-Pinvidic's post-doctoral research at the University of Strasbourg and Woods Hole Oceanographic Institution was supported by TOTAL. B. Tucholke's research was supported by NSF grant OCE0647035. Multichannel seismic field programs that provided much of the data used for this research were supported by NSF grants OCE839085, OCE830823 and OCE9819053