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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

The Effect of Cell Type on the Efficacy of CMV Antiviral Drugs

Meza, Benjamin 01 January 2008 (has links)
Until recently, all in vitro drug susceptibility assays of cytomegalovirus (CMV) were performed in clinically irrelevant fibroblast cells. This study sought to test if drug susceptibility was affected by cell type. MRC-5 embryonic lung fibroblasts and ARPE-19 retinal pigmented epithelial cells were infected with BADrUL131-Y4 epithelial/fibroblast tropic virus under serial concentrations of ganciclovir (GCV) or maribavir (MBV). Virus was quantified using plaque reduction, GFP fluorescence, and yield reduction. Both drugs performed less efficiently in ARPE-19 cells. A cell type effect was observed for both plaque reduction and yield reduction assays with implications for the treatment of CMV retinitis as well as other manifestations of CMV Disease that involve non-fibroblast cell types.
172

Transcriptional regulation of cardiac extracellular matrix gene expression and fibroblast phenotype by scleraxis

Adhikari Bagchi, Rushita 18 April 2016 (has links)
Cardiac fibrosis contributes to heart failure by dramatically impairing cardiac function, increasing patient morbidity and mortality. The primary fibrillar collagen expressed in the heart is type I, and increased collagen synthesis is the hallmark of cardiac fibrosis. Our laboratory has shown that the transcription factor scleraxis is sufficient to regulate the gene encoding collagen Iα2. The present thesis identifies and focuses on three key functions of scleraxis in the heart. First, we show that scleraxis is required for production of the cardiac extracellular matrix. Using in vitro and in vivo models, we observed a significant upregulation/reduction of matrix genes in response to induction/loss of scleraxis gene function respectively. In fact, scleraxis overexpression was sufficient to rescue matrix synthesis in scleraxis-null cells. In a murine model of cardiac pressure overload, scleraxis gene deletion blunted the induction of fibrotic collagen gene expression. Second, we provide evidence that scleraxis governs fibroblast-myofibroblast phenotype transition and fibroblast number. Scleraxis gene induction promoted cardiac myofibroblast phenoconversion while knockdown reduced myofibroblast marker gene expression. Scleraxis exerts direct transcriptional control on the a-smooth muscle actin gene-an established marker of myofibroblasts. Scleraxis null mice exhibited a dramatic reduction in cardiac fibroblast numbers- this is attributed to impairment of the epithelial-to-mesenchymal transition program which was marked by a corresponding loss of mesenchymal markers and increased epithelial markers. Loss-of-function experiments using primary cardiac proto-myofibroblasts recapitulated this paradigm, whereas scleraxis gene induction showed a reciprocal effect on mesenchymal markers. Third, data from this study supports the required role of scleraxis in the TGFb/Smad signaling pathway. Scleraxis is strongly upregulated by the potent pro-fibrotic cytokine TGFb, and works synergistically with the canonical Smad signaling pathway to increase Col1a2 expression by cardiac fibroblasts and myofibroblasts. Smad3 induced expression of the fibrillar collagens – an effect that was significantly attenuated following scleraxis knockdown. Smad3 binding to the Col1a2 gene promoter was significantly reduced in scleraxis null hearts. This study involved a comprehensive series of in vitro and in vivo experiments, and is the first to identify scleraxis as a key regulator of multiple fibroblast functions and a potential future target for therapeutic intervention in cardiac fibrosis. / May 2016
173

Modulation of Cardiac Fibroblast to Myofibroblast Transition by Rho-Associated Kinases ROCK1 and ROCK2

Hartmann, Svenja 18 October 2016 (has links)
No description available.
174

Role and regulation of the p53-homolog p73 in the transformation of normal human fibroblasts / Rolle und Regulation des p53-Homologs p73 in der Transformation normaler menschlicher Fibroblasten

Hofmann, Lars January 2008 (has links) (PDF)
The prototyical tumor suppressor p53 is able to arrest cells after DNA damage or as a response to oncogene expression. The transactivation-competent (TA) isoforms of the more recently discovered p53 family member p73 also prevent tumors, but the underlying mechanisms are less well understood. The work presented here addressed this issue by using a cell culture model of tumorigenesis in which normal human diploid fibroblasts are stepwise transduced with oncogenes. Cells in pretransformed stages were shown to harbour high levels of TAp73 mRNA and protein. This positive regulation was probably a result of pRB inactivation and derepression of E2F1, a key activator of TAp73. Consequences for such cells included an increased sensitivity to the cytostatic drug adriamycin, slower proliferation and reduced survival at high cell density, as demonstrated by rescue experiments using siRNA-mediated knockdown of TAp73. In order to identify potential effector pathways, the gene expression profile of siRNA treated, matched fibroblast cell lines with high and low TAp73 levels were compared in DNA microarrays. These findings support the notion of TAp73 up-regulation as an anti-proliferative defense mechanism, blocking the progress towards full transformation. This barrier could be overcome by the introduction of a constitutively active form of Ras which caused a switch from TAp73 to oncogenic DeltaNp73 expression, presumably through the phosphatidylinositol 3-kinase (PI3K) pathway. In summary, the results presented emphasize the tumor-suppressive function of TAp73 and indicate that its downregulation is a decisive event during the transformation of human cells by oncogenic Ras mutants. / Der gut untersuchte Tumorsuppressor p53 vermag das Wachstum von Zellen nach DNA-Schädigung oder Onkogenaktivierung zu arretieren. Die transaktivierungsfähigen (TA) Isoformen von p73, eines kürzlich entdeckten Mitgliedes der p53-Familie, können ebenfalls die Tumorentstehung verhindern. Die Mechanismen sind hier aber noch sehr unvollkommen verstanden. Zu deren Untersuchung wurde in der vorliegenden Arbeit ein Zellkulturmodell der Tumorentstehung verwendet, bei dem normale humane diploide Fibroblasten schrittweise mit bestimmten Onkogenen transduziert wurden. Zellen in unvollständig transformierten Stadien hatten hohe Spiegel an TAp73-mRNA und -Protein. Diese positive Regulation war vermutlich eine Folge von pRB-Inaktivierung und der Derepression von E2F1, einem der wichtigsten Aktivatoren von TAp73. Beobachtete Konsequenzen für solche Zellen waren höhere Empfindlichkeit für Zytostatika wie Adriamycin, langsameres Wachstum und geringere Überlebensfähigkeit bei hoher Zelldichte, was durch Rescue-Experimente mit siRNA-vermitteltem TAp73-Knock down gezeigt werden konnte. Um mögliche Effektor-Signalwege zu identifizieren, wurden die Genexpressionsprofile von siRNA-behandelten Fibroblastenlinien, die sich nur im TAp73-Spiegel unterschieden, in DNA microarrays verglichen. Die Befunde daraus lassen den Schluss zu, dass die Hochregulation von TAp73 einen antiproliferativen Schutzmechanimus darstellt, der die vollständige Transformation verhindert. Diese Barriere konnte überwunden werden durch die zusätzliche Präsenz von aktiviertem Ras, das einen Wechsel der Expression von TAp73 zu der von onkogenem DeltaNp73 bewirkte. Dies ist vermutlich abhängig vom Phosphatidylinositol-Signalweg. Zusammenfassend wurde die Rolle von TAp73 als Tumorsuppressor weiter gefestigt, da die Niederregulierung des Proteins eine zentrale Rolle in der Transformation menschlicher Zellen durch onkogene Ras-Mutanten spielt.
175

Die Rolle von p38 in der TGF-β- induzierten Transdifferenzierung humaner Tenonfibroblasten zu Myofibroblasten / The role of p38 in TGF-β-induced transdifferentiation of human tenonfibroblasts to myofibroblasts

Sieprath, Sonja January 2010 (has links) (PDF)
Hintergrund dieser Arbeit ist eine Charakterisierung der zellulären Signalkaskaden innerhalb von Tenonfibroblasten, die an einer überschießenden Wundheilung mit Vernarbung nach filtrierender Glaukomchirurgie beteiligt sind. Ein besseres Verständnis der zellinternen Abläufe soll neue Ansatzpunkte zur Vernarbungshemmung nach Trabekulektomie eröffnen. Die Ergebnisse dieser Arbeit weisen auf eine zentrale Rolle des p38-Signalweges für die Übermittlung der TGF-β-induzierten Transdifferenzierung humaner Tenonfibroblasten hin. Die Transdifferenzierung der HTF ist durch die nach 48 Stunden einsetzende Expression von Markerproteinen wie αSMA, der vermehrten Synthese von Matrixproteinen wie Collagen Iα1 und Fibronectin sowie Veränderungen der Zellmorphologie charakterisiert. Im Rahmen der Arbeit wurde die Aktivierung der p38 MAPK im Zeitverlauf betrachtet und verschiedene Aktivierungsformen von p38 herausgearbeitet: Die schnell einsetzende Aktivierung einer „hohen“ schweren p38-Isoform war meist nicht durch TGF-β an sich, sondern vielmehr durch eine mechanische Stimulation der Zellen bei Mediumwechsel zur Zugabe des Wachstumsfaktors bedingt. Demgegenüber war eine späte nach etwa 12 Stunden zu beobachtende Aktivierung einer „tiefen“ leichten p38-Isoform streng von der TGF-β-Stimulation sowie einem funktionsfähigen TGF-β-Rezeptor Typ I abhängig. Diese p38-Spätaktivierung ist zeitlich mit der TGF-β-induzierten αSMA-Expression assoziiert. Da die TGF-β-induzierte αSMA-Transkription durch Blockade der Proteinbiosynthese verhindert wird und eine zeitliche Lücke bis zur relevanten p38-Spätaktivierung besteht, ist offenbar die Synthese eines Zwischenboten notwendig. Als möglicher Kandidat für einen solchen Intermediator kam nach Literaturlage GADD45β in Frage: GADD45β konnte schließlich sowohl qualitativ als auch quantitativ nach TGF-β-Exposition in HTF nachgewiesen werden: Es wird mit einem deutlichen Maximum innerhalb der ersten Stunde für einige Stunden synthetisiert. Die beobachtete rasche SMAD2-Aktivierung in HTF, die in keinem direkten zeitlichen Zusammenhang zur αSMA-Expression steht, könnte verantwortlich für die Induktion von GADD45β sein und damit über Aktivierung von p38 zur Transdifferenzierung der Tenonfibroblasten zu Myofibroblasten beitragen. Für den weitergehenden Nachweis der Bedeutung von GADD45β ist dessen spezifische Blockade durch antisense-Überexpression mittels viralen Vektoren oder RNA-Interferenz anzustreben. Die durchgeführten Untersuchungen zeigen, dass GADD45β neben der p38 MAPK ein potentielles Ziel zur therapeutischen Modulation der TGF-β-vermittelten Transdifferenzierung von humanen Tenonfibroblasten darstellen kann. / Main problem after trabeculectomy in therapy of glaucoma is scarring. In search of new targets in modification of wound healing, a better understanding of cellular signal cascades of human tenonfibroblasts in transdifferentiation to myofibroblasts is aspired. TGF-β induces transdifferentiation of tenonfibroblasts, characterised by increased expression of marker proteins like αSMA and synthesis of matrix proteins like Collagen Iα1 and Fibronectin. Intracellular signal transducing of TGF-β by p38 seems to be essential. The time course of activation of the p38 MAPK was observed and a relevant late activation after 12 hours was found. Furthermore a mediatior in the meantime of the first hours was identified: GADD45β is induced in a chronological correlation. P38 and GADD45β could both be potential targets in modification of scarring after trabeculectomy.
176

Oxygen-mediated basic fibroblast growth factor (FGF2) effects on adult human dermal fibroblasts

Kashpur, Olga 08 May 2015 (has links)
This thesis investigates the effects of low oxygen culture conditions and fibroblast growth factor-2 (FGF2) on adult human dermal fibroblasts. It was previously shown that low oxygen and FGF2 culture conditions lead to an extension of proliferative lifespan, low-level activation of stem cell genes, and global transcriptional changes in adult human dermal fibroblasts. Additionally, an increased in vivo tissue regenerative response can be observed when human muscle-derived fibroblasts grown with FGF2 and low oxygen are implanted into mouse muscle injury, leading to a decrease in collagen deposition and scar formation and increase of functional skeletal muscle regeneration, including formation of Pax7+ muscle stem cells. These findings led to an analysis of key cellular oxygen sensors, hypoxia inducible factors (HIFs) and their role in this regenerative response. Directly linking these factors with the regenerative response, I have shown, with knockdown experiments, that HIF-2α is required for the increased proliferative capability and decreased senescence of human dermal fibroblasts (hDFs) induced by hypoxia. I have also determined that low oxygen causes an early and transient increase of HIF-1α and late and sustained increase of HIF-2α protein accompanied by increased nuclear translocation. Using overexpression and knockdown approaches via lent-virus, I determined that HIF-2α appears to modulate FGF2 signaling through the FGF receptors. First, under low oxygen conditions, exogenous FGF2 led to downregulation of endogenous FGF2, which can be mimicked by overexpression of HIF-2α. In ambient oxygen we didn't see this effect. Second, HIF-2α overexpression appears to lead to increases in FGFR1 phosphorylation and consequently increased ERK1/2 phosphorylation, and increases in the expression of heparan sulfate modifying enzymes (NDST1, NDST2, and EXTL2). Lastly, sustained supplementation with FGF2 in low oxygen inhibits receptor-mediated FGF2 signaling. To understand these effects at the transcriptional level, using microarray technology, we identified oxygen-mediated FGF2 effects on genes involved in cell survival and proliferation. Through bioinformatics analyses, I determined that genes involved in wound healing (extracellular matrix genes, adhesion molecules, cytokines) are upregulated in FGF2 treated fibroblasts grown under low oxygen. By utilizing a gain-of-function approach, we were able to assess the effects of altered HIF-2α activity on the expression of Oct4, Sox2, Nanog, Rex1, and Lin28 in adult hDFs. The results indicate that overexpression of the HIF-2α transcription factor increases Oct4 mRNA, but not Oct4 protein, levels, and had no effect on Nanog and Lin28 proteins. HIF-2α overexpression also mediated FGF2 induction of Sox2 and Rex1 proteins of higher molecular weight. This thesis expands our knowledge about effects of low oxygen and FGF2 on adult human dermal fibroblasts and explains in part, how FGF2 under low oxygen conditions may lead to increased proliferation, extended life span, regenerative competency and increased developmental plasticity of adult hDFs.
177

HIGH-RESOLUTION STRUCTURES OF THE PROTEINS HUMAN KALLIKREIN 6 AND HUMAN FIBROBLAST GROWTH FACTOR-1: STRUCTURE AND FUNCTION RELATIONSHIPS

Bernett, Matthew John Unknown Date (has links)
In this work, we examine the structure and function of two important human proteins. The first is human kallikrein 6 (hK6), which is a newly identified enzyme in the serine proteinase family that is expressed in the central nervous system. In chapter 2, the X-ray crystal structure of mature, active recombinant human kallikrein 6 at 1.75 Å is presented. This high resolution model provides the first three-dimensional view of one of the human kallikreins and one of only a few structures of serine proteinases predominantly expressed in the central nervous system. Enzymatic and X-ray data provide support for the characterization of human kallikrein 6 as a degradative proteinase with structural features more similar to trypsin than the regulatory kallikreins. In chapter 3, we have re-solved the structure of hK6 to a resolution of 1.56 Å. In addition, a detailed analysis of the preferred substrate specificity of hK6 at the positions P3, P2, P1′, P2′, and P3′ is undertaken using internally quenched fluorescent substrates based on a peptide background sequence of the identified autolysis region. Furthermore, the identified optimized substrate sequence is modeled into the 1.56 Å structure of human kallikrein 6 using docking in order to identify structural aspects of the protein responsible for this preference. The substrate specificity data show that human kallikrein 6 displays little discrimination for particular amino acids at the tested positions with the exception of P2′, where there is a pronounced preference for proline. The second protein studied in this work is human fibroblast growth factor-1 which is a member of the β-trefoil superfold. In chapter 4, a 1.10 Å atomic-resolution x-ray structure of human fibroblast growth factor 1, a member of the β-trefoil superfold, is reported. The FGF-1 structure exhibits numerous core packing defects detectable using a 1.0Å radius probe. In addition to contributing to the relatively low thermal stability of FGF-1, these defects may also permit domain motions within the structure. The availability of refined ADP's permits a translation/libration/ screw (TLS) analysis of putative rigid body domains. The observed rigid body motion in FGF-1 appears related to the ligand-binding functionalities. / Dissertation / PhD
178

Efeitos da elevada concentração de glicose sobre a reciclagem de integrinas contendo a subunidade b1 em fibroblastos. / Effects of high glucose concentration on the recycling of b1-containing integrins in fibroblasts.

Monteiro, Kelly Salzmann 03 October 2014 (has links)
Introdução: In vivo ou in vitro a exposição de fibroblastos a alta concentração de glicose promove um aumento do estresse oxidativo e consequentemente prejudica a migração celular, assim como a maturação da adesão. Além disso, a elevada concentração de glicose reduz a expressão de diferentes integrinas na superfície celular devido alterações na síntese do receptor e sua reciclagem. Objetivo: Avaliar os efeitos da elevada concentração de glicose no tráfego de vesículas contendo EEA1 (endossomos primários), Rab4 (via rápida da reciclagem), Rab11 (via lenta de reciclagem) e Rab7 (endossomos de degradação) em fibroblastos NIH3T3. Métodos: células foram cultivadas em meio contendo baixa concentração de glicose (LG, 5 mM) ou em alta concentração (HG 25 mM) durante 21 dias antes de realizar os experimentos. EEA1, Rab4, Rab11 e Rab7 expressão e distribuição foram avaliados por western blotting e imunofluorescência, respectivamente. Resultados: Células expostas à alta concentração não apresentaram diferenças na expressão e distribuição das proteínas EEA1 e Rab7, enquanto a expressão de Rab11 foi reduzida em 30%. Conclusão: a alta concentração de glicose altera a via lenta da reciclagem contendo Rab11, afetando potencialmente a reciclagem de integrinas e outros receptores e a sua expressão na superfície celular. / Background: In vivo or in vitro exposure of fibroblasts to high glucose concentrations (HG) promotes oxidative stress and consequently impairs cell migration, also inhibiting adhesion maturation. Additionally, HG reduces the expression of different integrins on the cell surface, potentially due to altered receptor synthesis and recycling. Aim: to evaluate the effects of HG on the trafficking vesicles containing EEA1 (early endosomes), Rab4 (fast recycling pathway) and Rab7 (endocytic degradation pathway) on NIH3T3 fibroblasts. Methods: cells were cultured under low glucose (LG, 5 mM) or HG (25 mM) concentrations during 21 days before the assays. EEA1, Rab4 and Rab7 expression and distribution were evaluated by western blotting and immunofluorescence, respectively. Results: HG did not affect proteins EEA1 and Rab7 expression and distribution, whereas Rab11 expression was reduced by 30%. The number of vesicles containing Rab11 was also significantly reduced in HG cells. Conclusion: high glucose alters the slow recycling endocytic pathway via Rab11, potentially affecting integrins and other receptors synthesis and expression on the cell surface.
179

Estudo de expressão gênica e de comportamento celular em células de indivíduos portadores de craniossinostoses sindrômicas / Gene expression and cell behavior study in cells from individuals with syndromic craniosynostosis

Fanganiello, Roberto Dalto 04 February 2010 (has links)
Um dos grupos de doenças mais importante que acomete o desenvolvimento da caixa craniana humana é o das craniossinostoses, caracterizado pelo fechamento prematuro de uma ou mais suturas cranianas. Entre as formas mendelianas das craniossinostoses sindrômicas, mutações dominantes em FGFR2 são uma das causas mais frequentes e estão associadas às síndromes de Apert, de Crouzon e de Pfeiffer. A sinalização intracelular subseqüente à ativação de FGFR2, tanto selvagem quanto mutante, é bastante intrincada e pode sofrer inúmeras bifurcações. As porções iniciais destas vias, imediatamente subsequentes à ativação do receptor, são relativamente bem compreendidas. Grande parte, porém, do controle dessas vias, principalmente no que tange a regulação transcricional e sua associação com alterações em comportamentos celulares, não é entendido. Assim sendo, os objetivos gerais deste trabalho foram: 1) estudar o potencial de diferenciação e o perfil diferencial de transcrição gênica de culturas primárias de células fibroblastóides isoladas a partir do periósteo das suturas coronais de pacientes acometidos por síndrome de Apert (heterozigotos para a mutação de ganho de função p.Ser252Trp em FGFR2, a mutação mais comum em pacientes com esta síndrome) e 2) estudar o potencial de diferenciação osteogênico e o perfil transcricional respectivamente de células mesenquimais e de tecido provenientes de sutura coronal de um modelo murino para Síndromes de Crouzon/Pfeiffer (heterozigotos para a mutação p.Cys342Tyr em Fgfr2, a mutação mais comum associada a estas síndromes). Certificamo-nos da expressão gênica e proteica de FGFR2 nas células fibroblastóides humanas e de Fgfr2 nas células mesenquimais murinas. Em seguida, testamos o potencial osteogênico (in vitro e in vivo ) e adipogênico (in vitro ) das células de pacientes com Síndrome de Apert, comparadas a células do mesmo tecido mas de indivíduos sem esta mutação e o potencial osteogênico (in vitro ) das células mesenquimais de camundongos portadores da mutação p.Cys342Tyr em Fgfr2, comparadas a células também das suturas coronais mas de animais selvagens. O potencial de diferenciação das células mutantes, nos dois grupos de experimentos, foi muito aumentado em relação ao potencial das células livres destas mutações. Conduzimos experimentos de microarrays de expressão gênica (sistema CodeLink) com 7 amostras de culturas primárias de células de pacientes com S. de Apert e as comparamos com 7 amostras de culturas primárias controles. Identificamos 263 genes com valores de expressão estatisticamente diferentes (SNR ≥ |0.4|, P ≤ 0,05) nas amostras de pacientes com S. de Apert quando comparadas às controles (118 superexpressos, 145 subexpressos). Categorias funcionais enriquecidas foram regulação de proliferação celular, metabolismo de nucleotídeos, regulação de expressão gênica, adesão celular, organização de matriz extracelular e cascata PI3K MAPK. Para a validação deste experimento constatamos superexpressão, por PCR em tempo real, de genes identificados como superexpressos na assinatura de expressão associada às células mutadas, além de verificarmos o mesmo comportamento destes genes em células controles tratadas com FGF2 exógeno para superativação do receptor. Os experimentos de expressão gênica com os tecidos de suturas coronais do modelo murino foram feitos com 15 amostras de tecidos de animais mutantes em 3 grupos de 5 e comparadas a amostras de mesmo tecido de animais selvagens agrupadas da mesma forma. Identificamos três listas de genes diferencialmente expressos: a primeira contendo 188 transcritos (P ≤0,05, FC ≥ 1,5,sendo 91 superexpressos e 97 subexpressos), e as outras duas filtradas previamente para coeficiente de variação < 50% dentro de cada grupo, contendo 488 transcritos (P ≤0,05, FC ≥ 1,2, sendo 183 superexpressos e 305 subexpressos) e 31 transcritos (P ≤0,05, FC ≥ 1,5, sendo 11 superexpressos e 20 subexpressos). Categorias funcionais mais enriquecidas foram crescimento, proliferação e ciclo celular, diferenciação celular, sinalização célula-célula, resposta imune mediada por células e sinalização por receptor Wnt. Estes resultados nos permitiram: a) demonstrar que células fibroblastóides de periósteo craniano de paciente portadores de S. de Apert (mutação p.Ser252Trp em FGFR2) e células mesenquimais do modelo murino para S. de Crouzon e Pfeiffer, portador da mutação p.Cys342Tyr em Fgfr2, apresentam potencial osteogênico aumentado, agregando evidências que sugerem que esta alteração de comportamento celular tem função fundamental no desencadeamento das craniossinostoses nestas síndromes; b) revelar assinaturas de expressão gênicas associadas a estas mutações nas condições estudadas, que podem reger este comportamento celular anormal; c) identificar um novo grupo de genes associados à patofisiologia da Síndrome de Apert ou às características fenotípicas do modelo murino investigado, podendo também ser genes candidatos a outras craniossinostoses de causa desconhecida. / Craniosynostosis is one of the most important group of diseases linked to the development of the human skull and is characterized by the premature fusion of one or more cranial sutures. Dominant mutations in FGFR2 are frequent molecular causes amongst the mendelian inherited forms of the syndromic craniosynostosis and are associated to Apert, Crouzon and Pfeiffer syndromes. The intracellular signaling pathways following the activation of wild type or mutant FGFR2 are very complex due to several possible bifurcations. The initial portions of these pathways, immediately following the receptor activation, are relatively well delineated. However the great majority of the events related to the control of these pathways is still not well understood, mainly concerning its transcriptional regulation and its association to other cell behavior anomalies. Therefore the key scopes of this work were: 1) to study the differentiation potential and the differential gene expression profile of primary fibroblastoid cell cultures isolated from the periosteum of the coronal sutures of Apert Syndrome patients (heterozygous for the mutation p.Ser252Trp in FGFR2, the most common cause of the Apert Syndrome condition) and 2) to study the osteogenic differentiation potential and the transcriptional profile of mesenchymal cells and tissue isolated from the coronal sutures of a mouse model for the Crouzon and Pfeiffer Syndromes (heterozygous for the p.Cys342Tyr mutation in Fgfr2, the mutation most commonly associated to these syndromes). We assured the FGFR2 /FGFR2 gene and the protein expression in human fibroblastoid cells and Fgfr2 /Fgfr2 expression in the mesenchymal murine cells. We tested the (in vitro and in vivo ) osteogenic and the (in vitro ) adipogenic potentials of the Apert Syndrome patients cells compared to cells from the same tissue but from subjects without this mutation and the (in vitro ) osteogenic potential of mesenchymal cells from mice bearing the p.Cys342Tyr mutation in Fgfr2 compared to coronal suture cells but from wild type mice. On both experiments the differentiation potential of the mutant cells were very increased when compared to the potential of the wild type cells. We conducted gene expression microarray experiments (CodeLink system) using 7 samples from primary cultures of cells from Apert Syndrome patients compared to 7 samples from primary control cultures. We identified 263 genes with significantly different expression (SNR ≥ |0.4|, P ≤ 0,05) associated to the Apert Syndrome profile (118 upregulated, 145 downregulated). Enriched functional cathegories were regulation of cell proliferation, nucleotide metabolism, gene expression regulation, cell adhesion, extracellular matrix organization and PI3K MAPK cascades. In order to validate this gene expression signature we confirmed through Real-Time PCR the upregulation of genes identified as upregulated in the Apert cell profile in samples from the microarray experiment and in control cells treated with exogenous overactivate the receptor. The gene expression experiments with the coronal suture tissues from the mouse model were performed with 15 samples of mutant animal tissue in 3 groups of 5 and compared to samples from the same tissue of wild type animals, with identical grouping. We identified three sets of differentially expressed genes: the first set containing 188 transcripts (P ≤0,05, FC ≥ 1,5, 91 upregulated e 97 downregulated), and the other two filtered for coeficient of variation < 50% in each group, containing 488 transcripts (P ≤0,05, FC ≥ 1,2, sendo 183 upregulated and 305downregulated) e 31 transcripts (P ≤0,05, FC ≥ 1,5, 11 upregulated and 20 downregulated). The most enriched functional categories were growth, proliferation and cell cycle, cell differentiation, cell-to-cell signaling, cell mediated immune response and Wnt receptor signaling. These results allowed us: a) to demonstrate that fibroblastoid cells from coronal periosteum PF Apert Syndrome patients (p.Ser252Trp mutation in FGFR2) and mesenchymal cells from the coronal tissue of the mouse model for Crouzon and Pfeiffer syndromes (bearing the p.Cys342Tyr in Fgfr2) have enhanced osteogenic potential, summoning evidences suggesting that this cell behavior alteration have a fundamental role to the craniosynostotic process in these syndromes; b) to unravel gene expression signatures linked to these mutations in the studied conditions, that could orchestrate this abnormal cell behavior; c) to identify a ser of genes associated to the pathophysiology of Apert Syndrome and to the phenotypic characteristics of the animal model investigated, which might be candidate genes to other craniosynostosis of unknown cause.
180

DYNAMIC CONTROL OF HYDROGEL PROPERTIES VIA ENZYMATIC REACTIONS

Dustin Michael Moore (6621656) 10 June 2019 (has links)
Two Systems were designed. The first permits tunable on-demand softening of a hydrogel network. The second permits reversible on demand ligand exchange within a hydrogel network. Both means were shown to be cytocompatible and their uses demonstrated in cell culture of mesenchymal stem cells and 3T3 fibroblast cells.

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