La peau est un organe se trouvant à l’interface de notre organisme et de notre environnement. Ellesubit un vieillissement qui se traduit par des modifications affectant ses différentes couches. Parmi celles-cile derme est particulièrement affecté. Les fibroblastes, présents dans le derme, synthétisent des moléculesde la matrice extracellulaire ainsi que des enzymes de dégradation. Lors du vieillissement, cette sécrétionest modifiée favorisant ainsi la sécrétion d’enzymes et la dégradation du derme. L’un des objectifs de ces travaux de thèse est d’évaluer les modifications ayant lieu chez les fibroblastes lors du vieillissement. Pour cela, trois modèles de vieillissement de fibroblastes primaires dermiques humains ont été développés et caractérisés. Une étude transcriptomique a été réalisée par PCR quantitative en temps réel et a permis de mettre en évidence des différences d’expression de gènes codant pour des composants du derme. Dans le but de développer des actifs cosmétiques à visée « anti-âge », des extraits riches en polysaccharides ont été réalisés à partir de plantes et de microorganismes, puis leur efficacité a été évaluée sur des modèles de peaux humaines. L’appareil de Golgi est un organite jouant un rôle majeur dans la modification post-traductionnelle et la sécrétion. La modification structurale de celui-ci lors du vieillissement a été évaluée sur les modèles de fibroblastes en utilisant des techniques de microcopie optique et électronique. Les résultats montrent une altération de la morphologie du réseau trans-golgien chez les fibroblastes sénescents, l’un des modèles développés au cours de ces travaux. Chez ces cellules, le TGN présente une morphologie particulière qui s’étend dans le cytoplasme. Ainsi, lors de la sénescence, nous avons pu révéler par le biais d’une étude transcriptomique que l’expression de gènes impliqués dans la structure et la fonctionnalité de l’appareil de Golgi étaient modifiée. Les résultats obtenus lors de cette thèse ont permis de mettre en évidence de nouveaux marqueurs biologiques innovants pour le criblage d’actifs dermo-cosmétiques à visée «anti-âge». / Skin is an important organ of the human body representing a protective structure in direct contactwith the external environment. During aging, skin undergoes dramatic changes including alteration ofdermal cells and components. Among these, fibroblasts synthetize and secrete a large variety ofcomponents and degrading enzymes involved in the modulation of dermal structure and functions. It isestablished that modification of the secreted components and enzymes during aging is related to dermisdegradation. This work aims to characterize aging-related alteration in fibroblasts. For this purpose, three aged human dermal primary fibroblast models have been developed. A transcriptomic study, using real-time quantitative PCR, has also been undertaken and has shown modifications in the expression of genesencoding dermal proteins. Using these results and in order to develop “anti-aging” cosmetic ingredients, extracts from polysaccharides-rich plant and microbial cells have been prepared and their efficiency evaluated on skin explants.As the Golgi apparatus is a major organelle of the secretory pathway, its structural organization has been investigated in fibroblasts using microscopy. The data show a marked alteration of trans-Golgi network morphology in aged cells. In contrast to its small and compact structure in young cells, the trans-Golgi network displays a large and expanded configuration in senescent cells. In addition, a transcriptomic analysis reveals that the expression of some genes, related to Golgi shape and/or function, is significantly modified in senescent cells. These genes could be then, used as innovating targets for the screening of novel dermo-cosmetic products with anti-aging activity.

Thesis advisor: Marc L. Snapper / Chapter 1: A review of Shapiro reactions as a coupling strategy in natural product total synthesis. The syntheses of lycoramine, galanthamine, yuehchukene analogues, ovalicin, studies toward the ingenol core, haemanthidine, pretazettine, tazettine, crinamine, Taxol, colombiasin A, elisapterosin B, the AB ring fragment of spongistatin 1 and 8-epipuupewhedione are discussed. Chapter 2: The convergent total synthesis of the marine natural product norrisolide is described. Both subunits, the hydrindane core and the norrisane side chain, are prepared in an asymmetric fashion through kinetic resolution and enantioselective cyclopropanation, respectively. A Shapiro reaction couples the two fragments and a Peterson olefination installs the 1,1-disubstituted olefin. Chapter 3: Preliminary experiments to isolate the biological target of norrisolide through reductive alkylation and tritium labeling are investigated. Further experiments are proposed to shed light on the primary norrisolide-protein interactions. / Thesis (PhD) — Boston College, 2009. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

by Yubing Li. / "September 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (p. 173-190). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

El citoesqueleto de actina es imprescindible para el mantenimiento de la morfología celular, así como para realizar diversas funciones como la movilidad/migración y división celular. En términos generales, este componente del citoesqueleto está constituido por los filamentos de actina o microfilamentos (MFs) y por una serie de proteínas de unión y/o relacionadas con la actina, implicadas en la organización estructural de los MFs y en la regulación de la dinámica de polimerización/despolimerización de actina. Una forma sencilla y eficaz de interferir en la dinámica de actina es mediante el uso de toxinas de actina. En este trabajo se ha realizado un estudio exhaustivo de los efectos provocados por estas toxinas a nivel de la morfología celular, arquitectura y de salida de proteínas del aparato de Golgi, bien por depolimerización de los MFs (citocalasina D, latrunculina B, micalolide B o toxina botulínica C2) o bien por su polimerización aberrante o estabilización (jasplakinolide). El análisis de los efectos provocados por las distintas toxinas revela como éstos son dependientes del tipo celular, modo de acción de la toxina así como de la concentración y tiempo de exposición a esta. Hemos observado como los cambios de la morfología de las cisternas producto de la despolimerización de los MFs se correlacionan con variaciones en la homeostasis el pH de este orgánulo. Según lo cual, pensamos que los MFs participan en el diseño y mantenimiento de la forma aplanada de las cisternas del aparato de Golgi, probablemente regulando, en parte, la maquinaria molecular implicada en el mantenimiento de la homeostasis iónica de este orgánulo. Por otro lado, hemos observado como los MFs participan de forma variable en la salida del aparato de Golgi de cargo no asociado a balsas lipídicas con destino basolateral y apical. Sin embargo, son prescindibles en la salida de cargo asociado a balsas lipídicas con destino apical. Paralelamente a estos resultados que implican a los MFs en la morfo-funcionalidad del aparato de Golgi, hemos desarrollado un modelo celular para generación de agresomas de actina filamentosa, los cuales han sido descritos en distintas enfermedades como el Alzheimer o el acoholismo crónico bajo el nombre de cuerpos de Hirano. En este sentido, el jasplakinolide es capaz de inducir la formación reversible de un agresoma de actina filamentosa similar al cuerpo de Hirano cuya degradación está mediada por los sistemas proteasomal y lisosomal/autofagia. Por último, describimos por primera vez in vitro la generación y coexistencia de dos agresomas originados por mecanismos diferentes sin que tenga lugar en ningún momento la mezcla de sus componentes moleculares.

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2007. / Härtill 3 uppsatser.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Title from first page of PDF file (viewed Feb. 12, 2009). Includes bibliographical references.

Thesis (Ph.D.)--University of Tennessee Health Science Center, 2008. / Title from title page screen (viewed on September 9, 2008). Research advisor: Marko Z. Radic, Ph.D. Document formatted into pages (xi,111 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 91-111).

Universiẗat, Diss., 2001--Köln.

Universiẗat, Diss., 2005--Bielefeld.

GORAB is a protein that localises to the trans-Golgi network (TGN) and is known to interact with Rab6. The loss of GORAB leads to gerodermia osteodysplastica (GO), an autosomal recessive disorder which results in lax skin, precocious skin aging, osteoporosis, susceptibility to fractures and joint hyperelasticity. Both the function of GORAB and the mechanism of pathogenesis in GO patients are poorly defined. In this study, the cellular functions of GORAB have been investigated. Using a variety of approaches (yeast two-hybrid assays, pull-downs with recombinant proteins, proximity biotinylation assays combined with mass spectrometry and co-immunoprecipitations) it was possible to establish a network of interactions with Golgi-localised proteins, including Arf GTPases and the COPI-associated protein Scyl1, that suggests a possible role of GORAB in COPI-mediated trafficking. Consistent with this hypothesis, ultrastructural changes of the Golgi apparatus were observed as were abnormal protein glycosylation in primary skin fibroblasts derived from GO patients, detected using both lectin binding assays and mass spectrometric glycan profiling. Moreover, immuno-electron microscopy studies revealed unequal distribution of GORAB within the TGN and fluorescence recovery after photobleaching experiments show GORAB being very stably associated with Golgi membranes. These properties of GORAB seem to result from its ability to oligomerise and to interact with vimentin filaments. Based on these data, a model of GORAB acting as a scaffolding protein that organises sites of COPI budding at the TGN has been proposed. Additionally, analysis of both published and newly identified GORAB mutations found in GO patients revealed that they affect various properties of GORAB including its interaction with small GTPases and GORAB ability to oligomerise, which suggests that these features are important for GORAB cellular functions. Together, these data suggest that the underlying cause of the skin and bone defects observed in GO patients is impaired COPI trafficking at the Golgi apparatus resulting in abnormal glycosylation of extracellular matrix proteins.