<p>Fibroblasts continuously strive to organize and compact the surrounding extracellular matrix (ECM). Recent data suggest that this cellular contractility controls interstitial fluid homeostasis in loose connective tissues (CT). The aim of this thesis was to study the effects of prostaglandins on fibroblast contractility and to investigate whether fibroblasts in the interstitial CT surrounding the human endolymphatic duct (ED) can modulate inner ear fluid pressure and endolymph resorption. </p><p>Paper I shows that prostaglandin E1 (PGE₁) and prostacyclin inhibit fibroblast-mediated collagen matrix compaction <i>in vitro</i> and lower the interstitial fluid pressure <i>in vivo</i> in rat dermis. Paper II demonstrates that the inhibition of collagen matrix compaction by PGE₁ is protein kinase A-dependent. Furthermore, PGE₁ induces a complete but reversible actin depolymerization in human dermal fibroblasts by affecting the phosphorylation state of regulatory actin-binding proteins. Paper III describes that the cells of the interstitial CT encompassing the human ED are organized in a network based on intercellular- and cell-ECM contacts. Paper IV shows that two distinct cell phenotypes populate this interstitial CT: one expressing the lymph endothelial marker podoplanin and the other a fibroblast marker. Furthermore, CT cells isolated from human ED tissues exhibited the same tissue compacting properties <i>in vitro</i> as dermal fibroblasts. </p><p>In conclusion, PGE₁ inhibits fibroblast contractility by interfering with the stability and dynamics of the actin cytoskeleton, which leads to a loss of integrin-mediated adhesion to the ECM. These mechanisms are supposedly involved in edema formation in skin during inflammation and might be involved in the formation of endolymphatic hydrops in the inner ear of patients with Ménière’s disease.</p>

The goal of our work was to characterize more precisely the role of ADAMTS2 in physiological and pathological processes, in order to develop potential therapeutic applications. We confirmed that the function of ADAMTS2 is essential during embryogenesis and development, including by its major role in the processing of fibrillar collagens type I and III in skin and lung tissues. Its specific activity was also matched up with that of two other aminoprocollagen peptidases, ADAMTS3 and ADAMTS14. The impact of ADAMTS2 inhibition during pathological formation of scar fibrous tissue was determined in two murine models of hepatic fibrosis and granulomatous reaction. In this context, ADAMTS2 appears as a therapeutic target of interest for the treatment of all process characterized by the deposition of an excessive scar matrix, including liver fibrosis. Finally, the potential anti-angiogenic properties of ADAMTS2 were demonstrated both in vitro and in vivo. Its potent activity during angiogenesis results from its action onto several distinct steps participating to the formation of new blood vessels. Molecular mechanisms by which ADAMTS2 modulates the behaviour of endothelial cells and inhibits tumor growth remain to be confirmed. L'objectif de nos études était de caractériser de manière plus précise le rôle de l'ADAMTS2 dans des processus physiologiques et pathologiques, et d'en déduire d'éventuelles applications en thérapeutique clinique. Nous avons confirmé que l'ADAMTS2 détenait une fonction essentielle au cours de l'embryogenèse et du développement, notamment par son rôle majeur dans la maturation des procollagènes fibrillaires de type I et de type III dans la peau et le poumon. Son activité spécifique a également été mise en perspective avec celle des deux autres aminoprocollagène peptidases, les ADAMTS3 et 14. L'impact de l'inhibition de l'ADAMTS2 au cours de la formation pathologique de tissu fibreux cicatriciel a été démontré dans des modèles murins de fibrose hépatique et de réaction granulomateuse à corps étranger. A ce titre, l'ADAMTS2 apparaît comme une cible thérapeutique d'intérêt pour le traitement de toute affection caractérisée par le dépôt d'une trame cicatricielle excessive, dont la fibrose hépatique. Enfin, le potentiel anti-angiogène de l'ADAMTS2 a été démontré à la fois in vitro et in vivo. Son efficacité remarquable résulte de son action au cours de plusieurs étapes distinctes de la formation des néo-vaisseaux. Les mécanismes moléculaires précis par lesquels l'ADAMTS2 agit sur les cellules endothéliales et l'inhibition de la croissance tumorale restent à préciser.

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Fibroblasts continuously strive to organize and compact the surrounding extracellular matrix (ECM). Recent data suggest that this cellular contractility controls interstitial fluid homeostasis in loose connective tissues (CT). The aim of this thesis was to study the effects of prostaglandins on fibroblast contractility and to investigate whether fibroblasts in the interstitial CT surrounding the human endolymphatic duct (ED) can modulate inner ear fluid pressure and endolymph resorption. Paper I shows that prostaglandin E1 (PGE1) and prostacyclin inhibit fibroblast-mediated collagen matrix compaction in vitro and lower the interstitial fluid pressure in vivo in rat dermis. Paper II demonstrates that the inhibition of collagen matrix compaction by PGE1 is protein kinase A-dependent. Furthermore, PGE1 induces a complete but reversible actin depolymerization in human dermal fibroblasts by affecting the phosphorylation state of regulatory actin-binding proteins. Paper III describes that the cells of the interstitial CT encompassing the human ED are organized in a network based on intercellular- and cell-ECM contacts. Paper IV shows that two distinct cell phenotypes populate this interstitial CT: one expressing the lymph endothelial marker podoplanin and the other a fibroblast marker. Furthermore, CT cells isolated from human ED tissues exhibited the same tissue compacting properties in vitro as dermal fibroblasts. In conclusion, PGE1 inhibits fibroblast contractility by interfering with the stability and dynamics of the actin cytoskeleton, which leads to a loss of integrin-mediated adhesion to the ECM. These mechanisms are supposedly involved in edema formation in skin during inflammation and might be involved in the formation of endolymphatic hydrops in the inner ear of patients with Ménière’s disease.

In this thesis, we aim to analyze the computational aspects of discourse annotation. Discourse is not only a concatenation of sentences / in fact the totality of discourse is more than the sum total of the sentences that constitute it. The property that differentiates discourse from a set of arbitrary sentences is defined as coherence. Coherence is established by the relations between the parts of discourse. We have a lexicalized approach to discourse, therefore in this study, discourse relations are considered to be set up by lexical items called discourse connectives. Systematic analysis of coherence requires an annotated corpus in which coherence relations are encoded. We developed an annotation environment to be used in an ongoing discourse level annotation project which aims to generate a theory-neutral source of coherence relations. We followed a data-driven methodology in design of the data structure employed in the annotation software. For this reason, we examined the predicate-argument structure of connectives. This analysis shows that stand-off annotation technique is more suitable than an inline method for such an annotation environment. This thesis also include a brief discussion on the formal implications of coherence relation constructions.

The topic of the present dissertation is teachers’ everyday dilemmas and the use of language to deal with these dilemmas. The concept of dilemma is compared to the concept of risk and the concept of paradox. The theoretical background consists of sociological systems theory and linguistic pragmatic theory. The empirical data consist of observations of teachers in everyday situations. The theoretical and empirical approaches are used to illuminate each other. Teachers’ ways of dealing with dilemmas are described as use of linguistic resources. Results show that dilemmas are complex social phenomenon that include global system media, trust and language use. Teachers face dilemmas as unpredicted clashes of conflicting expectations. The conflicting expectations come into view as global system media and local trust. The resources required in the constructing of trust and rationality shows how teachers are dealing with dilemmas. Teachers’ ways of dealing with dilemmas come into view as use of linguistic resources for logic and modality.

Cutaneous wound healing is a complex process involving the migration of inflammatory cells to the wound site, deposition of extracellular matrix, and the reestablishment of an intact epithelial barrier. Re-epithelialization depends on the proliferation and directional migration of keratinocytes from the wound edges. Initially, keratinocytes migrate over a provisional wound matrix that is rich in fibronectin, and as the wound heals the provisional matrix becomes replaced by one consisting of collagen and proteoglycans. Re-epithelialization is tightly regulated by a variety of peptides such as growth factors, cytokines and proteases, and abnormalities may result in chronic non-healing wounds or hypertrophic scars. CCN2 (Connective Tissue Growth Factor) is a multifunctional protein with effects on cells and their interactions with the connective tissue. CCN2 is expressed in a variety of cell types and regulates numerous cell functions including proliferation, differentiation, adhesion, migration and stimulation of collagen production. While the importance of CCN2 for the fibrotic response has been well studied, its involvement in keratinocyte function has not yet been fully explored. Using an in vivo wound model, the expression of CCN2 was captured at the leading keratinocyte edge during re-epithelialization. In vitro, exogenous addition of CCN2 to human keratinocyte cultures promoted keratinocyte migration. Subsequently, integrin a5b1 was identified as an important mediator of CCN2 enhancement of keratinocyte adhesion to fibronectin. CCN2 activated the FAK-MAPK signaling pathway, and pretreatment with MEK1 specific inhibitor PD98059 markedly reduced CCN2-promoted keratinocyte migration. In vitro, CCN2 expression was induced by TGF-β1. Compared with inhibiting the SMAD pathway, blocking MAPK was more effective in reducing TGF-β1-induced CCN2 mRNA and protein expression. In addition, CCN2-induced keratinocyte spreading required FAK. Treatment with CCN2 led to actin disassembly and altered the activity of the Rho proteins and p190RhoGAP in keratinocytes. Furthermore, Cdc42 mediated CCN2-induced cell polarity. In conclusion, using in vivo and in vitro models, CCN2 was shown to regulate keratinocyte function by promoting keratinocyte adhesion, spreading and migration. A complete understanding of CCN2 expression in keratinocytes is crucial in order to develop novel therapies for wound healing.

Degenerative suspensory ligament desmitis (DSLD) is a debilitating disease of connective tissues seen in many breeds but has become prevalent in the Peruvian Pasohorse. DSLD is believed to be a genetic disorder caused by one primary founder and most likely has a recessive mode of inheritance although a dominant or co-dominant mode of inheritance has not been ruled out. A genome scan using 259 microsatellite markers was used to test for linkage disequilibrium between one or more markers and DSLD. Two groups of Peruvian Pasohorses were selected from one population including the US and Canada. The only difference between the two groups of horses besides the size of the two groups was the presence of DSLD in the affected group and the absence of DSLD in the unaffected group. It was assumed that differences seen between the two groups in homozygosity and or common allele frequency could be an indication of linkage to DSLD. As a connective tissue disorder, there were a large number of candidate genes forDSLD to consider, yet no identical human or animal model exists. The genome scan identified five chromosomal regions where statistically significant differences were seen between affected and unaffected sample populations that could be indications of linkage to DSLD. Those chromosomes were: ECA 6, 7, 11, 14, and 26. Sequencing of a portion of the G domain in the Chondroitin Sulfate Proteoglycan2 (CSPG2) gene has mostly ruled out that segment of chromosome 14 as having linkage to DSLD. Further research needs to be conducted in the regions of ECA 6,7,11 and 26 where statistically significant differences were seen between the affected and unaffected groups, especially on ECA 6 and 11 since possible candidate genes are located in those regions based on the human comparative map.

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2007. / Härtill 4 uppsatser.