Les exosomes sont des vésicules membranaires de 30 à 100 nm de diamètre, formées dans les endosomes multivésiculaires et sécrétées par la plupart des cellules. Les propriétés biophysiques et biochimiques des exosomes ainsi que les mécanismes permettant leur biogénèse et sécrétion ont fait l’objet de nombreuses études. Cependant, ces derniers sont encore méconnus, limitant l'analyse des fonctions des exosomes in vivo. Au moins deux mécanismes ont été proposés pour la biogénèse des exosomes : un mécanisme nécessiterait l’action de protéines impliquées dans le tri endosomal, les ESCRT (« endosomalsorting complex required for transport »). Un autre mécanisme serait indépendant de leur fonction. La sécrétion des exosomes, une fois générés dans les endosomes, requiert la petite GTPase, Rab27a, comme montré dans un modèle cellulaire humain. Mes travaux de thèse ont porté sur l’étude des mécanismes moléculaires impliqués dans la biogénèse et la sécrétion des exosomes. Une première étude visant à analyser la fonction de Rab27a dans des cellules murines, m’a permis de mettre en évidence l’existence de différentes populations d’exosomes, dont la sécrétion dépend ou non de Rab27a. Une deuxième étude a eu pour objectif d’analyser l’implication des ESCRT dans la biogénèse des exosomes dans des cellules HeLa CIITA. Le criblage d’une librairie d’ARN d’interférence dirigés contre les différentes protéines ESCRT, a permis l’identification de 7 molécules potentiellement impliquées dans cette voie : HRS, STAM1, TSG101, leur inactivation induisant la diminution de la sécrétion des exosomes. L’inactivation de CHMP4C, VPS4B,VTA1 et ALIX, au contraire, l’augmente. L’inhibition de l’expression de ces candidats suivie de l’analyse des exosomes sécrétés a démontré l’hétérogénéité des vésicules sécrétées, et une modification de leur taille et de leur composition protéique par rapport aux cellules contrôle. Plus particulièrement, l’inactivation d’ALIX induit une augmentation de lasécrétion d‘exosomes de plus grande taille, et l’enrichissement sélectif en molécules de CMH de classe II. En accord, j’ai montré que les cellules inactivées pour ALIX, aussi bien des cellules HeLa que des cellules dendritiques humaines ont une plus forte expression de CMH de classe II à la surface et dans des compartiments intracellulaires. Ces résultats suggèrent l’implication de certains membres de la famille ESCRT dans la voie de biogenèse et sécrétion des exosomes, ainsi qu’un rôle potentiel d’Alix dans le trafic des molécules CMH de classe II, et dans la modulation de la composition protéique des exosomes. / Exosomes are small membrane vesicles with sizes ranging from 30 to 100 nm in diameter, which are formed in multivesicular endosomes and secreted by most cell types. Numerous studies have focused on the biophysical and biochemical properties of exosomes, as well as the mechanisms of biogenesis and secretion of these vesicles. However, these aspects are not fully understood, which limits the analysis of the functions of exosomes in vivo. At least two mechanisms have been proposed for the biogenesis of exosomes : one would rely on the function of proteins involved in endosomal sorting, the ESCRT family (for “endosomal sorting complex required for transport”). Another mechanism would be independent of their activity. Once exosomes are formed in endosomes, their secretion requires the small GTPase RAB27A, as shown in a human cell line. The objective of my PhD project was to gain insights into the molecular mechanisms that drive exosome biogenesis and secretion. A first study performed to analyze the function of Rab27a in murine cells allowed me to show the existence of different populations of exosomes, dependent or not on Rab27a for their secretion. A second study was aimed at analyzing the involvement of ESCRT proteins in exosome biogenesis in HeLa-CIITA cells. Seven molecules potentially involved in this process were identified on the basis of the screening of an RNA interference library directed against the different ESCRT proteins: the inactivation of HRS, STAM1 and TSG101 induced a decrease in exosome secretion, whereas the down regulation of CHMP4C, VPS4B, VTA1 and ALIX increased it. Gene expression of the different candidate proteins was inhibited and exosomes secreted by these cells were analyzed: we showed the heterogeneity of the secreted vesicles, as well as an alteration of their size and protein composition, as compared to control cells. In particular, the inactivation of ALIX induced an increase in the secretion of larger vesicles, and the selective enrichment of these vesicles in MHC class II molecules. Accordingly, I showed that both HeLa-CIITA and human primary dendritic cells inactivated for ALIX possess a higher expression of MHC class II molecules at the cell surface and in intracellular compartments. These results suggest that some members of the ESCRT family are involved in the exosome biogenesis and secretion pathway, and propose a potential role of ALIX in the trafficking of MHC class II molecules and in the modulation of the protein composition of exosomes.

Platelet-derived growth factor (PDGF) isoforms, which bind to closely related a- and b-tyrosine kinase receptors, induce migration, proliferation, survival and differentiation of mesenchymal cells. They signal by the active receptor attracting Src homology 2 (SH2) domain containing proteins, which subsequently initiate a set of signaling pathways. The aim of this thesis was to elucidate regulatory mechanisms involved in PDGFRb signaling. In the first two projects we investigated the roles in downregulation of PDGFRb of two related adaptor proteins, i.e. ALG-2 interacting protein X (Alix) and His-domain containing protein tyrosine phosphatase (HD-PTP) functions of. We found that Alix and HD-PTP influence ubiquitination of PDGFRb following PDGF stimulation, by affecting the E3 ligase c-Cbl. Alix enhances complex formation between c-Cbl and PDGFRb, increases c-Cbl phosphorylation and decreases its stability. Interestingly, while both HD-PTP and Alix participate in degradation of PDGFRb, only Alix affects receptor internalization. Moreover, we demonstrated that absence of HD-PTP promotes cell proliferation. In conclusion, we suggest that both Alix and HD-PTP are important adaptor proteins in regulation of PDGFRb downregulation, although the observed differences between their actions suggest that Alix and HD-PTP exert their functions via different mechanisms. The third study explored the importance of tyrosine residue 857 in the activation loop of PDGFRb. We report that, in vitro the tyrosine residue 857 to phenylalanine (Y857F) mutant receptor kinase activity is diminished while in vivo it does not affect the phosphorylation of PDGFRb. The phosphorylation pattern of PDGFRb revealed that most sites in the Y857F mutant receptor were phosphorylated similarly as in the wild-type receptor. However, tyrosine residue 771 was found to be hyperphosphorylated in the Y857F mutant receptor. This may be due to defective phosphorylation and activation of SHP-2, since it has been shown to dephosphorylate the receptor at Y771. In addition, activation of the Erk1/2 and Akt pathways was defective downstream of the Y857F mutant receptor. Interestingly, the Y857F mutant receptor was able to mediate cell migration, but not proliferation. The last study investigated a role of the tyrosine kinase Fer in PDGF signaling. We showed that Fer interacted with and was activated by PDGFRb in a ligand-dependent manner. In cells depleted of Fer, receptor phosphorylation was decreased and phosphorylation of Stat3 was abolished, whereas Stat5, Erk1/2 and Akt were activated normally. Colony formation in soft agar was abolished in cells depleted of Fer, but no effect was seen on cell proliferation and migration. Since Stat3 has been shown to be involved in transformation, we speculate that phosphorylation of Stat3 in Fer-depleted cells, affects the ability of cells to form colonies.

Le vieillissement est l'un premier facteur de risque pour plusieurs maladies telles que l’athérosclérose, la fibrose, l’Alzheimer, le diabète de type 2 et le cancer. L'accumulation de cellules sénescentes avec l'âge contribue au développement de maladies liées à l'âge en induisant une inflammation chronique causée par le phénotype sécrétoire associé à la sénescence (SASP). Il y a également une augmentation de la sécrétion de vésicules extracellulaires (EV) lors de la sénescence. Les EV sont des structures à bicouche lipidique permettant le transport de molécules actives vers des cellules réceptrices. De plus, les EV participent aux effets pathologiques des cellules sénescentes. Ainsi, nous proposons que les macrophages sénescents participent au développement de maladies liées à l’âge en induisant l'inflammation par l’action combinée des facteurs solubles du SASP et des EV. Tout d'abord, nous avons établi un modèle de macrophages sénescents induit par l’oncogène Raf-1. Une analyse transcriptionnelle de notre modèle a démontré un profil inflammatoire régulé par Nf-κB. La sécrétion d'EV est également augmentée par les macrophages sénescents. En outre, les EV dérivées de macrophages sénescents sont enrichies en miARN, tels que miR-21, miR-155 et miR-132, ainsi qu'en protéines ribosomiques, qu'en protéine Alix et qu'en protéine Mvp. Les sécrétions des macrophages sénescents induisent un échappement de la sénescence chez les cellules MEF, probablement par l'action combinée des molécules solubles du SASP et des EV. Nous concluons que les macrophages sénescents sécrètent des signaux prolifératifs et inflammatoires dans les cellules réceptrices, ce qui suggère leur rôle potentiel dans le développement de cancer. Le traitement avec le navitoclax élimine les macrophages sénescents et pourrait prévenir leurs effets pathologiques. / Aging is the first risk factor for several diseases such as atherosclerosis, fibrosis, Alzheimer’s, type 2 diabetes and cancer. The accumulation of senescent cells with age contributes to development of age-related diseases by inducing chronic inflammation. This inflammation is induced by the senescence-associated secretory phenotype (SASP). During senescence, there is also an increase of extracellular vesicles (EV) secretion. EVs are lipid bilayer structures that allow the transport of active molecules to recipient cells. In addition, EVs participate in pathologic effects of senescent cells. Thus, we propose that senescent macrophages participate in development of age-related diseases by inducing inflammation through the combined effect of SASP soluble factors and EV. First, we established a model of senescent macrophages induced by the oncogene Raf-1. Transcriptional analysis of our model demonstrated an Nf-κB-regulated inflammatory profile. EV secretion is also increased by senescent macrophages. Moreover, EVs derived from senescent macrophages are enriched in miRNA, such as miR-21, miR-155 and miR-132, as well as ribosomal proteins, Alix protein an Mvp protein. Secretion of senescent macrophages induce senescence escape in MEF cell, probably through the combined action of SASP soluble factor and EV. We conclude that senescent macrophages secrete proliferative and inflammatory signals in recipient cell, suggesting their potential role in cancer development. Treatment with navitoclax eliminates senescent macrophages and may prevent their pathological effects.

Le présent mémoire de maîtrise s'intéresse à la question de l'image et en propose une exploration placée sous le signe du double. Entre recherche et création, poésie et photographie, éclatement formel et méditation ontologique, ce mémoire ouvre des dialogues pour tenter de comprendre, en deux temps, la mécanique des confluences et leur intérêt sur le plan des processus créateurs. À la croisée des notions qu'il embrasse : l'image ; et le faisceau de ses manifestations, qu'elles soient de l'ordre de l'empreinte (trace), de l'archive (souvenir) ou encore de l'aura (lumière). Fruit d'un travail à quatre mains, Empreintes invite tout d'abord à entrer en immersion dans un monde duel où le fond comme la forme participent de la perte des repères. Présenté dans un format hors norme (deux fois 66 pages disposées tête-bêche) , le recueil photo-poétique joue avec l'espace et le temps, proposant d'arpenter en cinq tableaux les paysages laissés par des êtres qui ont été aimés, qui ont été perdus. Une parole s'élève des blessures et du silence pour retrouver leur trace , se dégage peu à peu de ses propres ruines pour naître à elle-même – puis mourir à nouveau – en un cycle sans fin. Empreintes laisse ainsi sourdre la parole vivante en abordant, par le thème de l'eau, le deuil sous toutes ses formes. Pour soutenir ce recueil, la partie Création littéraire et photographie argentique : intermédialité pour une poétique de l'image offre ensuite une réflexion en deux parties . Un rapport de laboratoire permet de remonter le fil du processus créateur pour mieux saisir, par l'archivage, la genèse du recueil. Il présente les trois méthodes de création intermédiatiques expérimentées entre écriture et photographie. Un essai lyrique sur la photographe franco-canadienne Alix Cléo Roubaud (1952-1983) aborde enfin la magie du nu féminin pour clore cette quête de l'image en pleine lumière / This Master's thesis deals with the topic of images and leads its exploration with a dual-view. Midway between research and creation, poetry and photography, formal fragmentation and ontological meditation, this memoir opens dialogues in a two-stage attempt to understand the mechanics of confluences and their relevance with regard to creative processes. At the crossroads of notions covered : images ; and the irrange of manifestation, whether in terms of footprints (trace), archives (memory) or aura (light). Fruit of a four-hands work, Empreintes is first of all an invitation to immerse oneself in a dual world where both substance and form contribute to a loss of bearings. Presented in a non-standard size (twice 66 pages arranged head to tail), the photo-poetic collection plays with space and time, offering a five-step walk among landscapes deserted by beings once beloved, now forever lost . A Word rises from wounds and silence to recount them, emerges gradually from its own ruins to self- originate - then die again - in an endless cycle. Empreintes then lets the living Word arise in addressing mourning in all its forms by the theme of water. To support this collection, the Création littéraire et photographie argentique : intermédialité pour une poétique de l'image part then offers a reflection in two stages. A lab report traces back the thread of the creative process to better understand, via archiving, the genesis of the collection. It presents three methods of intermedia creation experienced between writing and photography. A lyrical essay on the French-Canadian photographer Alix Cléo Roubaud (1952-1983) eventually addresses the magic of the female nude in order to end this quest for images in full light.

I offer a cloud of observations about language and art. I will prioritize my questions about how language operates in art, the way it functions within my own studio practice, and locate aesthetic interstices throughout. There will be insights gleaned from the various orderers of order (Lacan, Saussure) and orderers of disorder (Derrida, Agamben), walks in terra-incognita, and even some poetry on my part. I will take this chance to orient myself among different structures and deconstructions that have piledup around language, aesthetics and art.

No description available.

This thesis is a proof-of-concept project that aims at modify and reuse existing communication protocols of wireless vehicle to vehicle communication in order to build a prototype of a real time graphical application that runs in an embedded environment. The application is a 2D visualization of the flow of material at a quarry and is built on top of existing communication protocols that enable wireless vehicle to vehicle communication according to the 802.11p standard for intelligent transport solutions. These communication protocols have already been used within the Volvo group in other research rojects, but not in a context of a real-time graphical 2D visualization. The application runs on an ALIX embedded motherboard and combined with the necessary hardware represent one node that makes the communication network. The visualization monitors the position of every active node in the network and the flow of material between material locations and crusher that process the material at the quarry. The visualization is implemented in C/C++ using Qt 4.6.2 Graphics View framework.

Pas de résumé en français / The goal of this research was the synthesis and spectroscopic, structural andphysical-chemical characterization of cyclic 6- and 7-membered hydroxamicacids, a tetrahydroxamic calix[4]arene-based tetrapodal receptor, and their metalcomplexes with trivalent and tetravalent metal cations. They were characterizedby several techniques such as 1H and 13C NMR, IR, and mass spectroscopies,single crystal X-ray analysis, and potentiometry. Cyclic hydroxamic acids arefound in a few mix siderophores but their coordination properties were stillunknown. The structural features of metal complexes formed with Fe(III),Ga(III), Ce(IV), Zr(IV), Hf(IV), U(IV) and U(VI) have been investigated both inthe solid state and in solution. The synthesis and complexation studies of anoriginal calix[4]arene-based tetrapodal receptor is described. Reactionparameters for all key steps in the synthetic route have been optimized. Thesingle X-ray crystal analysis of benzyl-protected receptor was obtained.Complexation studies with zirconium(IV) and hafnium(IV) evidenced theformation of two metal two ligand complexes rather than 1:1 species, whichwere shown to interact in solution with a third alkali cation

Thesis (M.A.)--Indiana University, 2010. / Title from screen (viewed on July 19, 2010). Department of English, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Karen Kovacik, Peggy Zeglin Brand, Ronda C. Henry. Includes vitae. Includes bibliographical references (leaves 79-83).

Indiana University-Purdue University Indianapolis (IUPUI) / My thesis examines the ways in which female performance poets deliver their messages and how those messages inspire, affirm, and encourage their audiences. From the traditions of outsider art—Beat poetry, feminist poetry, jazz, folk, punk, and rap—feminist performance poets choose the public sphere as a platform to witness to social injustices. In naming inequality, these poets challenge patriarchal foundations of gender roles, question academia’s criteria as to what constitutes “good” poetry, and expose social injustices. In this thesis, I examine the work of feminist performance poets Ani Difranco, Alix Olson, Andrea Gibson, Ursula Rucker, and Jessica Care Moore as examples of a new way of reading. Their work is significant in that they continue the tradition of feminist poetry by challenging the patriarchal status quo through a re-socializing and accessible style. Their work allows audiences to commune together in shared experience and promotes social change by demystifying cultural norms and gender codes in order to expose the exclusivity in patriarchal ideologies. These poets draw on a woman-centered spirituality, subvert misogynistic feminine archetypes, pay homage to ancestors and foremothers, and address issues of the body—naming oppression yet making room for pleasure.