Thesis (Ph. D.)--University of Alberta, 1994. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Alberta, 1994. / Includes bibliographical references.

Regeneration is, in simple terms, ‘to re-grow’ damaged or lost parts of the body (e.g. cells, tissues and organs) and is a natural phenomenon occurring throughout the life of an organism. The regenerative capacity varies in the animal kingdom. Invertebrates have high regenerative capacity in contrast to higher vertebrates. This raises several fundamental questions related to the regeneration potential, evolutionary selection and its cellular and molecular mechanisms. An in-depth knowledge in regeneration is warranted to answer the fundamental questions that are still a challenge in regenerative medicine.  Glycosaminoglycans (GAGs) are known to be involved in various physiological processes. Of several GAG types galactosaminoglycans are the focus of this thesis. Galactosaminoglycans such as chondroitin sulfate/dermatan sulfate (CS/DS) are anionic linear polysaccharides covalently linked to core proteins so called proteoglycans (PGs), and form an integral part of both cell surface and extracellular matrix components. Although CS/DS have been associated with different cellular processes from development to homeostasis, not many studies have been carried out to understand their role in regeneration. In this thesis, we aim to study galactosaminoglycans, their structure, and interaction with growth factors of biological importance in the process of regeneration using simple invertebrate model organisms - brittlestars. We have identified CS/DS as the major GAG present in brittlestars. Molecular characterization of these chains indicated a much higher level of sulfation in Amphiura filiformis than so far found in GAGs from invertebrates or vertebrates. This brittlestar CS/DS promotes FGF2 mediated cell signaling similar to heparin. Further, we studied the functional role of these CS/DS chains and their biosynthetic machinery during arm regeneration in A. filiformis. Regeneration is followed by an increase in GAG sulfation from blastema stage to the fully functional arm. Suppressing sulfation on the other hand by sodium chlorate treatment drastically affected the proliferation process and thereby regeneration. Thus our findings suggest a potential biological role of CS/DS in brittlestar limb regeneration that may have relevance to regenerative medicine in future.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Thesis (Ph.D.)--Baylor University, 2006. / Includes bibliographical references (p. 136-146).

Proteoglycans (PGs) are composed of highly sulfated glycosaminoglycans chains (GAGs) attached to specific core proteins. They are present in extracellular matrices, on the cell surface and in storage granules of hematopoietic cells. Heparan sulfate (HS) and chondroitin/dermatan sulfate (CS/DS) GAGs play indispensable roles in a wide range of biological processes, where they can serve as protein carriers, be involved in growth factor or morphogen gradient formation and act as co-receptors in signaling processes. Protein binding abilities of GAGs are believed to be predominantly dependent on the arrangement of the sugar modifications, sulfation and epimerization, into specific oligosaccharide sequences. Although the process of HS and CS/DS assembly and modification is not fully understood, a set of GAG biosynthetic enzymes have been fairly well studied and several mutations in genes encoding for this Golgi machinery have been linked to human genetic disorders. This thesis focuses on the zebrafish N-deacetylase/N-sulfotransferase gene family, encoding key enzymes in HS chain modification, as well as glycosyltransferases responsible for chondroitin/dermatan sulfate elongation present in zebrafish. Our data illustrates the strict spatio-temporal expression of both the NDST enzymes (Paper I) and CS/DS glycosyltransferases (Paper II) in the developing zebrafish embryo. In Paper III we took advantage of the four preexisting zebrafish mutants with defective GAG biosynthesis. We could demonstrate a relation between HS content and the severity of the pectoral fin defects, and additionally correlate impaired HS biosynthesis with altered chondrocyte intercalation. Interestingly, altered CS biosynthesis resulted in loss of the chondrocyte extracellular matrix. One of the main findings was the demonstration of the ratio between the HS biosynthesis enzyme Extl3 and the Csgalnact1/Csgalnact2 proteins, as a main factor influencing the HS/CS ratio. In Paper IV we used the newly developed CRISPR/Cas9 technique to create a collection of zebrafish mutants with defective GAG biosynthetic machineries. Lack of phenotypes linked to null-mutations of most of the investigated genes is striking in this study.

Orientador: Cristina Pontes Vicente / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T21:32:05Z (GMT). No. of bitstreams: 1 Godoy_JulianaAparecidaPretode_M.pdf: 1738296 bytes, checksum: 42d22e3271b69962a476983e12e359ed (MD5) Previous issue date: 2010 / Resumo: O dermatan sulfato (DS) é um glicosaminoglicano que pode atuar como um agente antitrombótico, anticoagulante e anti-inflamatório. A aterosclerose é uma doença que acomete os vasos sanguíneos através da formação exacerbada de placas de gordura, interrompendo o fluxo de sangue. A intervenção cirúrgica mais utilizada nesses casos é a angioplastia, entretanto, esse procedimento pode ocasionar uma lesão ao endotélio, onde células e proteínas inflamatórias são recrutadas ao local da lesão, promovendo a migração e proliferação das células musculares lisas ocasionando a reestenose (neointima) do vaso acometido. A recuperação do endotélio, momentos após a lesão, seria uma alternativa terapêutica com o objetivo de se evitar a formação de neointima. Essa recuperação poderia ser feita pelas células progenitoras endoteliais (EPC), existentes na população de células mononucleares (MNC), da medula óssea. Neste estudo, testamos o efeito do DS na inflamação, trombose, formação de neointima e migração de MNC em camundongos selvagens (C57BL06), testamos também o efeito do DS em conjunto com a administração de MNC na formação de neointima em camundongos selvagens, deficientes da proteína cofator II da heparina (HCII-/-) e deficientes em apolipoproteína E (ApoE-/-). Todos os animais analisados passaram por um procedimento cirúrgico na artéria carótida comum esquerda, mimetizando a lesão causada por angioplastia em humanos. Analisamos a formação de trombo, a presença de células inflamatórias e de P-selectina nos animais 1 ou 3 dias após a lesão arterial; a formação de neointima foi analisada 21 após a injúria arterial. Observamos uma inibição da trombose, diminuição de células CD45+ e da expressão de P-selectina no local da lesão nos animais selvagens tratados com DS. Foi observado, também, que nos animais selvagens que receberam MNCs ou MNCs + DS, a formação de neointima foi inibida. Nos animais selvagens tratados com MNC + DS, houve uma maior migração de MNC para o local da lesão. Nos animais HCII-/-, não houve inibição da formação da neointima em nenhum dos dois grupos (tratados com MNC e tratados com MNC + DS). Nos camundongos ApoE-/- a injeção de MNC mesmo em conjunto com o tratamento com DS não foi capaz de inibir a proliferação de neointima; houve melhora apenas quando se administrou o DS isoladamente. Com isso, concluímos que o DS participa da inibição dos processos trombótico e inflamatório, na sua fase inicial, após injúria arterial e promove também a migração de um número maior de MNCs para o local da lesão nos animais selvagens; nos animais ApoE-/-, o DS inibiu a resposta inflamatória inicial e a formação de neointima apenas quando administrado isoladamente, tendo seu efeito anulado quando este foi injetado conjuntamente com as MNC. Este dado sugere que o processo inflamatório local, o estágio de formação das placas de ateroma, o elevado índice de colesterol e os triglicerídeos circulantes podem influenciar no efeito do DS e na capacidade de recuperação do endotélio mediada pela MNCs injetadas nos camundongos ApoE-/-. / Abstract: Dermatan sulfate (DS) is a glycosaminoglycan that can act as an antithrombotic, anticoagulant and anti-inflammatory agent. Atherosclerosis is a disease that affects the blood vessels by an exacerbated fat plaques formation, blocking the blood flow. The most used surgical operation, in these cases, is the angioplasty; however, this procedure can cause a lesion to the endothelium, where inflammatory cells and proteins are recruited to the lesion site, promoting smooth muscle cells migration and proliferation, provoking restenosis (neointima) of the attempted vessel. The endothelium recovery, some time after lesion, would be a therapeutic strategy by preventing the neointima formation. This recovery could be done by the endothelial progenitor cells (EPC), present in mononuclear cells (MNC) population, from bone marrow. In this study, we devise the DS effect on inflammation, thrombosis, neointima formation and MNC migration in wild-type mice (C57BL06); we also devise DS effect together with MNC administration on neointima formation in wild-type mice, heparin cofactor II deficient mice (HCII-/-) and apolipoprotein E deficient mice (ApoE-/-). All analyzed animals suffered surgical operation in left common carotid artery, that mimics the lesion caused by angioplasty in humans. We analyzed thrombus formation, inflammatory cells presence and P-selectin in animals 1 and 3 days after lesion; neointima formation was analyzed 21 days after arterial injury. We observed a thrombus inhibition, decreased CD45+ cells and P-selectin expression at the lesion site in wild-type animals treated with DS. It was also observed in wild-type animals that received MNC or MNC + DS, the neointima formation was inhibited. In wild-type animals treated with MNC + DS, there were a higher MNC migration to the lesion site. In HCII-/- animals, there was not an inhibition in neointima formation in any of the two groups (treated with MNC or treated with MNC + DS). In ApoE-/- mice, the MNC injection even in DS presence, was not able to inhibit neointima proliferation; there was an improvement only when DS was administered alone. It follows that DS participate on thrombotic and inflammatory process inhibition, in the initial stages, after arterial injury and it also promote a higher MNC migration to the lesion site in wild-type animals; in ApoE-/- animals, DS inhibited the initial inflammatory response and neointima formation only when administered alone; its effect was null when it was injected together with MNC. This date suggest that local inflammatory process, atheroma plaque state, elevated cholesterol and triglyceride rates can influence on DS effect and on the capacity of endothelium recovery mediated by injected MNC in ApoE-/- mice. / Mestrado / Histologia / Mestre em Biologia Celular e Estrutural

Lam Shi Ying Joyce. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 107-114). / Abstract in English and Chinese. / Chapter CHAPTER 1 --- GENERAL INTRODUCTION --- p.1-19 / Chapter CHAPTER 2 --- EXPRESSION OF PROTEIN KINASE C (PKC) ISOFORMS IN THE VENTRAL TEMPORAL (VT) AND DORSAL NASAL (DN) RETINAL GROWTH CONES OF MOUSE EMBRYOS / INTRODUCTION --- p.20-22 / MATERIALS AND METHODS --- p.22-24 / RESULTS --- p.24-31 / DISCUSSION --- p.31-37 / FIGURES --- p.38-46 / Chapter CHAPTER 3 --- EFFECTS ON MOUSE NASAL AND TEMPORAL RETINAL NEURITES TO CHONDROITIN SULPHATES (CS) AFTER ALTERATION OF PKC ACTIVITY / INTRODUCTION --- p.47-48 / MATERIALS AND METHODS --- p.49-51 / RESULTS --- p.51-59 / DISCUSSION --- p.60-67 / FIGURES --- p.68-74 / Chapter CHAPTER 4 --- EFFECTS ON AXON ROUTING AFTER ALTERATION OF PKC ACTIVITY ON GUIDANCE OF RETINAL GANGLION CELL AXONS AT THE OPTIC CHIASM OF MOUSE EMBRYOS / INTRODUCTION --- p.75-76 / MATERIALS AND METHODS --- p.77-80 / RESULTS --- p.80-89 / DISCUSSION --- p.89-95 / FIGURES --- p.96-103 / Chapter CHAPTER 5 --- GENERAL CONCLUSION --- p.104-106 / REFERENCES --- p.107-114

Les carbohydrates font partie des trois grandes classes de biopolymères présents dans la nature. Ils représentent 75% de la biomasse. Les glycosaminoglycanes font partie des carbohydrates, ils sont présents à la surface des cellules et sont responsables de la signalisation cellulaire. Ils sont importants dans de nombreux processus biologiques. Vu leur importance en biologie et en santé, il est nécessaire de comprendre leur fonctionnement. Dans cette thèse nous avons étudié deux types de tétrasaccharides de glycosaminoglycanes (chondroïtine sulfate et dermatane sulfate) avec une nouvelle méthode qui couple la spectrométrie de masse à la spectroscopie vibrationnelle (MS/IR). Nous avons montré qu’avec cette méthode la signature de l’empreinte OH fonctionne pour les glycosaminoglycanes qui présentent des groupements Coo- et des groupements sulfate contrairement aux oses simples. Cette méthode a également validé la pertinence du séquençage pour l'élucidation de profils de sulfate et la nature de l’hexuronique dans les oligosaccharides de glycosaminoglycanes. L’approche du séquençage améliore considérablement la résolution structurelle par rapport à la simple analyse spectroscopique de l'ion précurseur. Elle permet d’avoir plus d’information sur les oligosaccharides. Et pour finir nous avons proposé un protocole pour l’analyse de mélanges afin de déterminer le ratio des différents éléments présents dans le mélange / Carbohydrates are among the three major classes of biopolymers found in nature. They represent 75% of the biomass. Glycosaminoglycans are carbohydrates, they are present on the surface of cells and are responsible for cell signaling. They are important in many biological processes. Given their importance in biology and health, it is necessary to understand their mechanism. In this thesis we studied two types of glycosaminoglycan tetrasaccharides (chondroitin sulfate and dermatan sulfate) with a new method that combines mass spectrometry with vibrational spectroscopy (MS / IR). We have shown that with this method the signature of the OH-fingerprint works for glycosaminoglycans which have COO- groups and sulfate groups in contrast to simple carbohydrates. This method also validated the relevance of sequencing for the elucidation of sulfate profiles and the nature of hexuronic in oligosaccharides of glycosaminoglycans. The sequencing approach significantly improves the structural resolution compared to the simple spectroscopic analysis of the precursor ion. It provides more information on oligosaccharides. And finally we proposed a protocol for the analysis of mixtures to determine the ratio of the different elements present in the mixture