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Wetzig, Andrew R., i n/a. "Olfactory Stem Cells From Adult Rats". Griffith University. School of Biomolecular and Biomedical Science, 2007. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070724.121953.
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The formation of neurospheres was important in demonstrating that neurogenesis in the adult brain may be fuelled by a stem cell population. The olfactory mucosa is another site of neurogenesis which, in humans, has been observed to contain a stem cell population through the formation of neurospheres (Murrell et al., 2005). Stem cells can be defined as cells capable of self-renewal and multipotency. The aim of this study was to investigate the potential of rat olfactory stem cells growing as neurospheres. The hypothesis is that the rat olfactory mucosa contains a 'true' stem cell population that can be cultured as neurospheres and that will demonstrate multipotency by differentiating into 'non-olfactory' cell types and possess the capacity for self-renewal, if provided with the appropriate environmental niche. Here it was found that adult rat olfactory mucosa is capable of generating neurospheres when cultured in EGF and bFGF. Evidence of self-renewal was provided by the formation of six generations of neurospheres, the formation of neurospheres from single cells and the expression of markers associated with self-renewal by neurosphere cells. The multipotency of olfactory neurosphere cells was demonstrated through manipulation of the stem cell niche. In defined culture conditions, extracellular matrix molecules and growth factors were able to induce the differentiation of neurosphere cells down the dopaminergic lineage pathway. When co-cultured with differentiating cells, neonatal myoblasts and 3T3-L1 cells, olfactory neurosphere cells were able to differentiate and incorporate into a skeletal muscle myotube and differentiate into adipocytes, respectively. In conclusion it was found that the adult rat olfactory mucosa is capable of generating neurospheres. When presented with an appropriate niche neurosphere cells are able to self-renew and demonstrate multipotency.
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Wetzig, Andrew R. "Olfactory Stem Cells From Adult Rats". Thesis, Griffith University, 2007. http://hdl.handle.net/10072/366121.
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The formation of neurospheres was important in demonstrating that neurogenesis in the adult brain may be fuelled by a stem cell population. The olfactory mucosa is another site of neurogenesis which, in humans, has been observed to contain a stem cell population through the formation of neurospheres (Murrell et al., 2005). Stem cells can be defined as cells capable of self-renewal and multipotency. The aim of this study was to investigate the potential of rat olfactory stem cells growing as neurospheres. The hypothesis is that the rat olfactory mucosa contains a 'true' stem cell population that can be cultured as neurospheres and that will demonstrate multipotency by differentiating into 'non-olfactory' cell types and possess the capacity for self-renewal, if provided with the appropriate environmental niche. Here it was found that adult rat olfactory mucosa is capable of generating neurospheres when cultured in EGF and bFGF. Evidence of self-renewal was provided by the formation of six generations of neurospheres, the formation of neurospheres from single cells and the expression of markers associated with self-renewal by neurosphere cells. The multipotency of olfactory neurosphere cells was demonstrated through manipulation of the stem cell niche. In defined culture conditions, extracellular matrix molecules and growth factors were able to induce the differentiation of neurosphere cells down the dopaminergic lineage pathway. When co-cultured with differentiating cells, neonatal myoblasts and 3T3-L1 cells, olfactory neurosphere cells were able to differentiate and incorporate into a skeletal muscle myotube and differentiate into adipocytes, respectively. In conclusion it was found that the adult rat olfactory mucosa is capable of generating neurospheres. When presented with an appropriate niche neurosphere cells are able to self-renew and demonstrate multipotency.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Biomedical Sciences
Faculty of Science
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Wuidart, Aline. "Defining the mechanisms regulating the switch from multipotency to unipotency during mammary gland development". Doctoral thesis, Universite Libre de Bruxelles, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/264618.
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Les cellules souches assurent le développement des tissus, leur renouvellement ainsique leur réparation suite à des blessures. L’une des questions clés du domaine de labiologie des cellules souches est l’identification des différents types cellulaires qu’unecellule souche peut donner. Les cellules souches peuvent être multipotentes, c’est-à-direcapables de donner naissance à plusieurs types cellulaires différents, ou unipotentes,c’est-à-dire qu’elles ne peuvent alors se différencier qu’en un seul type cellulaire. Lesexpériences de traçage cellulaire sont réalisées quotidiennement en biologie dudéveloppement et en biologie des cellules souches afin d’évaluer le devenir des cellulessouches in vivo. Cependant, il n’existe à ce jour aucune méthode rigoureuse permettantd’interpréter les résultats d’expériences de traçage cellulaire de manière non ambigüe etde déterminer la multipotence ou l’unipotence des cellules souches avec grande précisionet de manière statistiquement fiable. Nous avons développé de nouvelles méthodes afind’évaluer avec une très grande précision le caractère unipotent ou multipotent descellules souches du sein et de la prostate. Ces nouvelles découvertes démontrent demanière non ambigüe que la prostate provient de cellules souches multipotentes, alorsque seules des cellules souches unipotentes contribuent au développement et auremodelage de la glande mammaire au stade adulte. D’autre part, nous montrons que cesont des cellules souches multipotentes qui sont responsables des phases précoces dudéveloppement embryonnaire de la glande mammaire, et que ces cellules deviennentunipotentes peu avant la naissance. Nous avons étudié les mécanismes régulant le passagede l’état multipotent à l’état unipotent et démontrons que le facteur de transcription p63joue un rôle crucial dans la restriction du potentiel de différenciation des cellules souchesmammaires embryonnaires. Enfin, nous montrons que les cellules souches mammairesadultes, normalement unipotentes, peuvent redevenir multipotentes en conditionsphysiopathologiques telles que l’ablation spécifique d’une lignée cellulaire mammaire ouau cours de l’initiation tumorale. Nous essayons donc de comprendre de manière généraleles mécanismes impliqués dans le passage de l’état unipotent à l’état multipotent descellules souches mammaires adultes, et d’élucider les similarités existant entre lesdifférentes conditions dans lesquelles des cellules souches mammaires multipotentessont observées.Doctorat en Sciences biomédicales et pharmaceutiques (Médecine)
info:eu-repo/semantics/nonPublished
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McMurray, Rebecca Jane. "Nanoscale surfaces for the long-term maintenance of mesenchymal stem cell phenotype and multipotency". Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/3042/.
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The discovery of stem cells has led to rapid advances in the field of regenerative medicine. Their unique properties, including the ability to self-renew and differentiate make them ideal for the repair/replacement of tissues that have been damaged as a result of disease or injury. Mesenchymal stem cells in particular represent a highly valuable pool of adult stem cells for such regenerative applications due to their accessibility, and potential as an autologous patient derived autologous nature However current methods for the in vitro expansion of high quality autologous mesenchymal stem cells results in spontaneous differentiation of the stem cell population and a loss of differentiation capacity over time. In vivo, it is the stem cell niche that provides stem cells with the appropriate cues required to maintain stem cell self-renewal. It is proposed that by mimicking these cues using biomaterials, that the self-renewal of mesenchymal stem cells can be controlled in vitro. In this study, a novel nanopit topography was investigated for its effects on the maintenance and growth of mesenchymal stem cells in vitro. To investigate this, three main aspects of mesenchymal stem cell state were examined in response to this novel nanotopography: maintenance of the stem cell phenotype over time including expression of stem cell markers and differentiation potential over time, changes in signalling pathways associated with differentiation and lastly, the metabolic profile of stem cells. As a result of this study we have identified a novel nanopit topography, which in the absence of chemical supplements, provides a substrate that is conducive to the maintenance of mesenchymal stem cells. Small RNAs have also been implicated in the regulation of signalling pathways and the metabolic state of stem cells. Furthermore, the ability to produce nanotopographically-patterned substrates using current standard techniques provides an inexpensive, high throughput method for the production of novel tissue culture plastics suitable for the maintenance of mesenchymal stem cells.
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Gray, Simon Matthew. "PRC2-Mediated H3K27me3 Repression Promotes Effector CD8 + T Cell Terminal Differentiation and Loss of Multipotency". Thesis, Yale University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10584947.
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Elucidating how multipotent memory precursor (MP) cells maintain developmental plasticity and longevity to provide long-term immunity while most effector cells develop into terminally differentiated effector (TE) cells with limited survival is necessary for understanding immunological memory formation. We profiled active (H3K27Ac) and repressed (H3K27me3) chromatin states in naïve, MP and TE CD8+ T cells during viral infection, and observed increased H3K27me3 at numerous pro-memory and pro-survival genes in TE relative to MP cells, indicative of fate restriction, but permissive chromatin at both pro-memory and pro-effector genes in MP cells, indicative of multipotency. Deficiency in PRC2-mediated H3K27me3 deposition impaired clonal expansion and TE cell differentiation, but minimally impacted memory cell maturation. Abundant H3K27me3 deposition at pro-memory genes occurred relatively late during TE cell development in a FOXO1-regulated manner. These results outline a detailed temporal model for how effector T cells lose memory cell potential through selective epigenetic-silencing of pro-memory genes.
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Cwinn, Matthew. "'Suppressor of fused' antagonizes hedgehog signaling and is required to maintain retinal progenitor cell identity and multipotency". Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28214.
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The mature retina consists of six neuronal and one glial cell type that are derived from a pool of mulipotent progenitor cells (RPC). The decision to remain as a multipotent progenitor or to specify a particular retinal cell lineage and differentiate are governed by cell intrinsic and extrinsic factors. Sonic hedgehog (Shh) is a secreted lipoprotein that is motigenic for RPCs and influences cell fate decisions. Suppressor of fused (Sufu) is an intracellular antagonist of the pathway; however, its role in regulating Shh signaling and influencing cell fate decisions in RPCs are unknown. Here, I demonstrate that Sufu antagonizes the Hh pathway in RPCs both in vitro and in vivo. Surprisingly, Sufu was required to maintain early RPC identity and multipotency. Conditional deletion of Sufu in early RPCs resulted in the down-regulation of transcription factors required to maintain RPC identity and multipotency as well as transcription factors required to specify all seven retinal cell types.Sufu-null RPCs were incapable of differentiating into the normal complement of retinal cell types and instead differentiated into restricted subsets of interneurons. These data demonstrate that Sufu antagonizes the Hh pathway in RPCs and provides novel evidence that Sufu is required for proper progenitor cell behavior.
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Chang, Eun Hyuk. "The role of polycomb repressive complex 2 in postnatal subventricular zone neural stem/progenitor cell self-renewal and multipotency". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:1ddbd108-0256-4a4a-b40a-35818197ca39.
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The murine subventricular zone (SVZ) in a brain contains a population of stem cells and daily produces tens of thousands of neurons throughout lifetime. However, the mechanisms of SVZ neural stem/progenitor cell (NSPC) maintenance, differentiation and cell-fate specification are still not clear. To understand these parameters via histone methylations with bivalent mechanism, the SVZ NSPCs were first isolated by using a culture technique called neurosphere assay (NSA). It has been a challenge to culture pure cell populations of SVZ subtypes, so the NSA was initially validated. The H3K27me3 mark, which has a dominant role in the bivalent mechanism, has not been studied in postnatal and adult SVZ in vivo, yet their role has been implicated to control the shift of embryonic cortical neurogenesis to gliogenesis. Therefore, we have first investigated whether H3K27me3 marks are present in the postnatal and adult SVZ NSPC population and whether their marks have been changed after stroke or demyelination in central nervous system (CNS) by immunohistrochemistry. With the confirmation of H3K27me3 mark present in SVZ NSPCs, the presence of H3K27me3 catalyzer, called polycomb repressive complex 2 (PRC2) core components (Eed, Ezh2, Suz12) including Jarid2, was investigated and confirmed in postnatal SVZ in vitro by qRT-PCR and Western blot. To understand the role of PRC2 enzymatic activity in postnatal SVZ neurosphere self-renewal and multipotency, Eed was down-regulated by using lentiviral mediated delivery of shRNA. Also, PRC2 dependent or independent function of Jarid2 was examined via knockdown approach. The lack of Eed in the neurospheres resulted the attenuation of self-renewal and oligodendrogenesis, whereas the Jarid2 knockdown neurospheres showed the decreased proliferation with no SVZ NSPC differentiation. Based on these knockdown studies, it suggests Eed and Jarid2 might not share their function in the postnatal SVZ NSPCs to govern postnatal SVZ NSPC self-renewal and multipotency.
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Kole, Denis. "Role of Fibroblast Growth Factor 2 in Maintenance of Multipotency in Human Dermal Fibroblasts Treated with Xenopus Laevis Egg Extract Fractions". Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-dissertations/207.
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Current usage of human embryonic stem cells (hES) and induced pluripotent stem cells (iPS) in clinical therapies and personalized medicine are limited as a result of ethical, technical and medical problems that arise from isolation and generation of these cells. Isolation of hES cells faces ethical problems associated with their derivation from human pre-implantation embryos. The most controversial aspect of hES cell isolation targets the generation of autologous hES cell lines which requires the transfer of a somatic-cell nucleus from the patient to an enucleated oocyte. While already established embryonic stem cell lines from IVF embryos can be used in a similar manner, lack of genetic identity can cause therapy rejection from the host, and prevent their use in personalized medicine. Induced pluripotent stem cells on the other hand, are generated from somatic cells that have been reprogrammed in vitro to behave like stem cells. While these cells can potentially be used for personalized medicine without the risk of rejection by the host system, derivation methods prevent their therapeutic use. The most efficient method used to generate iPS cells involves usage of viral particles which can result in viral DNA being integrated in the host cell’s genome and render these cells non-compliant for clinical therapies. Other methods not involving viral particles exist as well, but the reprogramming efficiency is too low and technical problems with generating large enough numbers of cells prevent these methods from being feasible approaches for clinical therapies. Direct reprogramming of a differentiated cell into a developmentally more plastic cell would offer alternatives to applications in regenerative medicine that currently depend on either embryonic stem cells (ES), adult stem cells or iPS cells. We hypothesize that Xenopus laevis egg cytoplasmic extract contains critical factors needed for reprogramming that may allow for non-viral, chemically defined derivation of human induced pluripotent/multipotent cells which can be maintained by addition of exogenous FGF2. In this thesis we investigated a new method for generation of multipotent cells through determining the ability of select fractions of Xenopus laevis egg extract to induce multipotency in already differentiated cells. We were able to identify select fractions from the extract that in combination with exogenously added FGF2 can reprogram and maintain the reprogrammed cells in an undifferentiated state. The findings of this work also determined that Xenopus laevis egg extract mRNA is required for achieving full reprogramming. The body of work presented in this thesis showed the ability of FGF2 isoforms to bind and activate select FGF receptor tyrosine kinases, act as extracellular mitogenic factors to support growth of hES cells in an undifferentiated state as well bind to nuclear DNA and affect expression of endogenous genes. Moreover, we showed that all FGF2 isoforms can induce expression of stem cell specific proteins in human dermal fibroblasts as well as extend lifespan of human dermal fibroblasts in vitro. In this work we identified HECW1, the gene coding for E3 ubiquitin ligase NEDL1, as a novel nuclear target for all FGF2 isoforms and showed that overexpression of recombinant FGF2 isoforms in human dermal fibroblasts can down regulate expression of HECW1 gene.
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Philip, Diana Liz. "The Influence of Synthetic Microenvironments in Determining Stem Cell Fate". University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1627669247178055.
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Loison-Robert, Ludwig. "Cellule souche gingivale : origine et multipotence". Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC0083/document.
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La gencive correspond à un modèle de régénération naturelle grâce notamment à sa capacité de cicatrisation « ad integrum ». Ce phénomène est permis par sa composition en fibroblastes gingivaux. Ces cellules, composante cellulaire principale du tissu conjonctif gingival, sont au cœur de la régulation des réponses inflammatoires et de la cicatrisation. Ce tissu contient, comme d’autres tissus mésenchymateux, des cellules souches ; qui expliquent en partie ces capacités de régénération. De plus, comme le tissu gingival est abondant et facilement accessible, l’utilisation de ces cellules souches pourraient être d’un intérêt prometteur en thérapie cellulaire ou pour de la modélisation in vitro. Au cours de cette thèse, nous avons pu montrer que les Cellules Souches dérivées de la Gencive Humaine (CSGH) possèdent des propriétés communes avec les cellules souches adultes dérivées des crêtes neurales. Ces cellules peuvent être qualifiées de « souche » par leur capacité d’auto-renouvèlement, d’adhésion au plastique et de multipotence. Premièrement, nous avons montré que la méthode ainsi que les produits de culture utilisés pour l’isolation des fibroblastes gingivaux in vitro à partir de biopsies de gencive avait une influence sur les cellules obtenues. Dans un second temps, une analyse clonale in vitro de populations de fibroblastes gingivaux a permis de montrer que les fibroblastes gingivaux sont composés de sous-populations qui expriment des marqueurs spécifiques des cellules souches et des crêtes neurales. Outre leur origine embryologique, l’étude de leur multipotence a aussi été caractérisée après expansion et en fonction des additifs utilisés. Pour finir, deux exemples d’utilisation de ces cellules comme modèle d’étude de la biocompatibilité de biomatériaux in vitro ont été développés; imitant la muqueuse buccale ainsi que les réactions dentaires (réparatrices et réactionnaire)Gingiva is a natural regeneration model thanks to its "ad integrum" healing capability. Gingival fibroblasts are the main actors of this property. These cells, the main cellular component of the gingival connective tissue, regulate the inflammatory responses and healing process. This tissue contains, like many others, mesenchymal stem cells; which also partly explain these regenerative abilities. Moreover, as the gingiva is abundant and easily accessible, the use of these stem cells may interest cell therapy or in vitro model tissues responses. In this work, we demonstrated that Stem Cells Derived from Human Gingiva (SCHG) have common properties with neural crest adult stem cells. These cells can be called "stem cells" for their ability to self-renew, adhere to plastic and to differentiate. First, we have shown that the method and the culture products used for isolation of gingival fibroblasts from gingival biopsy had an influence on the obtained cells. Secondly, an analysis of in vitro clonal populations of gingival fibroblasts has shown that gingival fibroblasts are composed of subpopulations that express specific markers of stem cells and neural crests. In addition to their embryological origin, the study of their multipotency was also characterized after expansion and depending on the used additives. Finally, two examples of using these cells and dental pulp stem cells as a model to study the in vitro biocompatibility of biomaterials have been developed, mimicking oral mucosa or dentin reactions (reparative or reactional)
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Bondue, Antoine. "Mesp1 functions in multipotent cardiovascular progenitor specification". Doctoral thesis, Universite Libre de Bruxelles, 2009. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210319.
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During embryonic development, multipotent cardiovascular progenitor cells (MCPs) are specified from early mesoderm. Although the core cardiac transcriptional machinery acting during cardiac cell differentiation is relatively well known, the molecular mechanism acting upstream of these cardiac transcriptional factors, and promoting cardiac progenitor specification from early mesoderm remains poorly understood. We used embryonic stem cell (ESC) differentiation as a model to dissect the molecular mechanisms implicated in cardiovascular progenitor specification. Using ESCs, in which gene expression can be temporally regulated, we showed that transient expression of Mesp1 dramatically accelerates and enhances multipotent cardiovascular progenitor specification through an intrinsic and cellular autonomous mechanism. Using genome wide transcriptional analysis, we found that Mesp1 rapidly activates and represses a discrete set of genes. Using chromatin immunoprecipitation, we showed that Mesp1 directly binds to regulatory DNA sequences located in the promoter of many key genes belonging to the core cardiac transcriptional machinery, resulting in their rapid upregulation. Mesp1 also directly and strongly represses the expression of key genes regulating other early mesoderm and endoderm cell fates. Using engineered ESC expressing the green fluorescent protein under the control of the Mesp1 promoter, we isolated Mesp1 expressing cells in differentiating ESCs allowing characterization of the cellular and molecular mechanisms underlying cardiovascular specification. Our results demonstrate that Mesp1 acts as a key regulatory switch during cardiovascular specification, residing at the top of the hierarchy of the gene network responsible for cardiovascular cell fate determination. Moreover our results place Mesp1 upstream of the specification of both first and second heart fields and provide novel and important insights into the molecular mechanisms underlying the earliest step of cardiovascular specification. We identified cell surface markers expressed allowing the isolation of early cardiovascular progenitors and provide potentially novel methods for dramatically increasing the number of cardiovascular cells for cellular therapy in humans.Doctorat en sciences médicales
info:eu-repo/semantics/nonPublished
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McBride, Sarah. "ELUCIDATING BIOPHYSICAL CUES CONDUCIVE TO TARGETED MULTIPOTENT CELL DIFFERENTIATION". Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1196435881.
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Claudinot, Stéphanie. "Potentialité des keratinocytes clonogéniques : filiation avec les cellules souches". Paris 6, 2004. http://www.theses.fr/2004PA066058.
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Heins, Nico. "Intrinsic fate determinants of neural and multipotent CNS precursor cells". Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-45202.
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Craig, Laura A. "Differentiation of multipotent skin derived precursor cells into skeletal muscle". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80245.
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The potential use of stem cells for therapy depends on our ability to optimize differentiation conditions to best take advantage of their multipotentiality. Skin derived precursor cells (SKPs) are recently described adult stem cells that have been shown to differentiate into both neuronal and mesodermal cell types in vitro. We asked specifically whether they could be induced to differentiate into skeletal muscle. An accurate assay for detecting skeletal muscle was first developed, using RT-PCR, immunocytochemistry and Western blotting. We then used traditional differentiation methods, and found that SKPs could differentiate into cells expressing an immature skeletal muscle phenotype, as determined by appropriate morphology and expression of various skeletal muscle markers. By modifying this protocol, we observed a small percentage of multinucleated, fused myotubes, suggesting that SKPs have the potential to differentiate into mature skeletal muscle given appropriate conditions. Future work could enhance this population, creating an accessible, new source of cells for autologous transplants.
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Zepponi, Vanessa. "Les progéniteurs multipotents exprimant Flt3 source des précurseurs T extra-thymiques". Phd thesis, Université René Descartes - Paris V, 2012. http://tel.archives-ouvertes.fr/tel-00806094.
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Les cellules souches hématopoïétiques (CSH) de phénotype LSK (Ligneage-c-Kit+Sca1+) sont à l'origine de toutes les lignées sanguines. Leur maturation passe parla génération de progéniteurs multipotents (MPP), subdivisés grâce à l'expression deVCAM-1 et Flt3 (VCAM-1+Flt3-: MPP1, VCAM-1+Flt3+: MPP2 et VCAM-1-Flt3+:MPP3). Les MPP3 se différencient en progéniteur lymphoïde commun (CLP), sourcede la lignée B. Sa contribution à la génération de la lignée T reste controversée.La lignée T principale est issue d'un progéniteur de la MO qui a colonisé le thymus. Ilexiste aussi une lignée T extra-thymique, identifiés au sein de différents organes(l'intestin, la MO, le sang et la rate) dont la maturation se termine dans le thymus oul'intestin. Une des questions importantes est de savoir si ces 2 lignées sont issues de lamême source. Nous nous sommes intéressés à la lignée de pré-T extra-thymique (de larate) : Lin-Thy1.2+ CD25+Il7R��+. Ces derniers sont très abondants chez la sourisathymique (5-6 fois plus que chez la souris contrôle C57BL/6). Notre but a été dedéfinir la source de cette lignée parmi les progéniteurs de la MO. Suite aux transplantations des différents compartiments hématopoïétiques de la MO àdes receveurs athymiques irradiés, nous avons montré que les MPP3 (VCAM1-Flt3+)sont la population plus douée d'activité pré-T. Au contraire, les CLP génèrent deslymphocytes B matures (CD19+IgM+). Ces données sont confortées par l'étude del'expression de gènes lymphoïdes et myéloïdes qui indique l'engagement lymphoïdeprécoce d'une sous- population de MPP3. Les cellules progénitrices de la MO quicolonisent la rate (et le thymus) doivent circuler par le sang pour pouvoir coloniser cesorganes. La population de MPP majoritaire en circulation est les MPP3. De plus,l'analyse du profil d'expression des gènes des récepteurs aux chimiokines et d'autresgènes spécifique de la différentiation apporte de nouvelles informations sur le potentielT intrinsèque des progéniteurs de la MO.L'ensemble des données accumulées permettent de conclure que les MPP3 sont debons candidats pour la génération des pré-T extra-thymiques et que l'engagementlymphoïde commencé dans la MO se termine dans le sang grâce au maintien del'expression de Notch1.
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Ali, Hamad. "Neuronal potential of umbilical cord blood non-hematopoietic multipotent stem cells". Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1277.
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The human central nervous system, one of the most complex organ systems anatomically and physiologically in the human body, is the body control center which manages and coordinates functions of all different organ systems. The lack of effective treatments and therapeutic intervention make injuries and disorders associated with the central nervous system one of the most dangerous and fatal health conditions worldwide. The adult nervous system has a limited capability of self-repair and regeneration following either a neurological disorder or injury. Despite being limited and ineffective in initiating recovery from injuries and disorders, this property opened the doors for a new direction of research aimed at investigating the possibility of developing therapies and treatments for central nervous system injuries and disorders based on the concept of regeneration and cell transplantations. Stem cells have gained significant public attention over the past decade due to their differentiation capabilities and potential utilization in clinical applications. The ability to differentiate stem cells into neural lineages including neurons and glial cells, highlighted their potential role as a therapeutic tool for central nervous system injuries and disorders. The main aim of this thesis is to show that umbilical cord blood stem cells are a potential source of cells that could be used therapeutically in central nervous system injuries and disorders. A distinct population of cells has been purified from human umbilical cord blood. These cells have been characterized and differentiated in-vitro into neuron-like cells using fully defined sequential neuronal induction protocol. The differentiated cells were shown to have similar morphological and functional properties to developing central nervous system endogenous neurons using several different techniques, including immunocytochemistry, real-time PCR, cDNA arrays and calcium imaging. The results highlight the potential role of umbilical cord blood stem cells as a therapeutic tool for central nervous system injuries and disorders for which current mode of therapy is inadequate. In addition, they might provide an in-vitro model of neural cells for toxicology and drugs testing research.
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Downey, Jennifer. "Identification and isolation of multipotent stromal cells from human skeletal muscle". Mémoire, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6296.
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Abstract: Human skeletal muscle is an essential source of various cellular progenitors with potential therapeutic perspectives. Muscle-resident mesenchymal stromal cells (mrMSCs) are thought to be involved in the development of several regenerative disorders such as fatty degeneration, heterotopic ossification and fibrosis. Identifying the cell population responsible for these pathologies will help better understand the underlying mechanisms and lead to more efficient treatment. We first developed an isolation method and culture conditions for the proliferation and maintenance of the adherent fraction of human skeletal muscle derived cells. To further enrich the cell population as multipotent progenitors, we used fluorescent-activated cell sorting (FACS) and known mesenchymal stromal cell (MSC) markers. The enriched cell populations obtained were tested for their multipotent capabilities towards the osteogenic, adipogenic and chondrogenic lineages. The CD73 + CD 105+ CD90- subset of human skeletal muscle adherent cells displayed robust multipotence to all three lineages under the appropriate differentiation conditions. Clonal differentiation assays confirmed that all three lineages stem from a single multipotent progenitor. Furthermore, this cell subset was able to differentiate into brown adipocyte-like cells, expressing UCP1 at the RNA and protein levels following prolonged stimulation with rosiglitazone (ROS). This result suggests that this cell subset could also represent a human cell model for brown adipogenesis. The cell isolation and enrichment method presented in this thesis represent a novel technique to obtain human mrMSCs. This method holds great promise for future clinical applications with the enriched cell populations since they are expanded in a defined medium, which supports inter-laboratory reproducibility. Furthermore, the phenotypic markers chosen for the FACS isolation are well conserved amongst donors in the proposed conditions, limiting donor-to-donor variability.||Résumé: Le muscle squelettique humain est une source essentielle de cellules progénitrices ayant plusieurs applications thérapeutiques potentielles. Les cellules stromales mésenchymateuses du muscle squelettique humain (hmrMSCs) semblent être impliquées dans des pathologies telles l’ossification hétérotopique, la dégénérescence graisseuse et la fibrose. L’identification de la population cellulaire à l’origine de ces pathologies permettrait de mieux comprendre les mécanismes derrières celles-ci et aiderait à la création de traitements plus efficaces. Nous avons d’abord mis au point une méthode d'isolement et déterminer des conditions de culture pour la prolifération et le maintien en culture de la fraction cellulaire adhérente dérivée du muscle squelettique humain. Par le biais de la cytométrie en flux et des marqueurs connus des cellules stromales mésenchymateuses (MSC), nous avons pu enrichir les cellules stromales multipotentes. Le potentiel ostéogénique, adipogénique et chondrogénique des populations cellulaires enrichies a été évalué par des essais de différenciation. La sous-population de cellules CD73[indice supérieur +]CD105[indice supérieur +]CD90[indice supérieur -] a montré une multipotence robuste sur les trois lignées étudiées. Des essais de différenciation clonale ont confirmés que les trois lignées obtenues proviennent tous d’un progéniteur multipotent commun. De plus, cette sous-population cellulaire avait la capacité de se différencier en cellule de gras brun, démontrée par une expression élevée d’UCP1 au niveau génique et protéique suivant une stimulation continue avec le rosiglitazone (ROS). Ce résultat suggère que cette sous-population cellulaire pourrait également représenter un modèle pour l’adipogenèse vers le gras brun. La méthode d’enrichissement présentée représente une nouvelle technique afin d’obtenir des hmrMSCs. Elle semble prometteuse pour de futures applications cliniques employant ces cellules, étant donné qu’elles sont amplifiées dans un milieu défini permettant une reproductibilité interlaboratoire. De plus, les marqueurs de phénotype choisis pour l’enrichissement par cytométrie en flux sont bien conservés entre individus, limitant la variabilité inter-donneur.[symboles non conformes]
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Kaanta, Alice. "Evidence for a Novel Multipotent Mammary Progenitor with Pregnancy-Specific Activity". Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10069.
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The mouse mammary gland has emerged as a model system for studying processes involved in the development of epithelial tissues. Current evidence suggests the existence of a differentiation hierarchy in the mammary gland, consisting of a stem cell capable of reconstituting the tissue, progenitors with the capacity to produce specific functional cell types, and differentiated cells with limited or no repopulation potential. Although markers for mammary stem cells and progenitors have been identified, these populations have not been isolated to purity and our understanding of how they function in different stages of mammary development remains incomplete. Many adult stem cells are mitotically quiescent and can therefore retain a DNA or histone label significantly longer than differentiated cells. In an attempt to identify mammary stem cells/progenitors by histone label retention, I crossed a mouse carrying the tetracycline-inducible histone 2b/eGFP (H2BGFP) gene with tetracycline transactivator strains expected to induce H2BGFP in the mammary gland. H2BGFP expression was induced in the mammary gland until puberty and then chased for 6-8 weeks; \(H2BGFP^+\) label retaining cells were isolated and assayed. Transplantation experiments comparing MMTVrtTA/H2BGFP MECs isolated after induction to MMTVrtTA/H2BGFP MECs retaining label post-chase failed to prove that label retention enriches for stem cells/progenitors in the MMTVrtTA/H2BGFP system. During the course of these experiments, I unexpectedly discovered that MMTVrtTA induced H2BGFP expression exclusively in the \(CD24^+/CD29^+\) and \(CD24^+/CD29^{lo}\) populations, which contain stem cells and progenitors, respectively. Interestingly, I also discovered that H2BGFP+/CD24+/CD29lo MECs developed limited mammary outgrowths in vivo and that pregnancy increased the repopulation ability of these cells by 5-10-fold. H2BGFP+/CD24+/CD29lo outgrowths contained all mammary lineages and produced milk, but were unable to self-renew in serial transplant assays. Furthermore, \(H2BGFP^+/CD24^+/CD29^{lo}\) and \(H2BGFP^-/CD24^+/CD29^{lo}\) MECs had distinct gene expression profiles, with H2BGFP+/CD24+/CD29lo MECs expressing lower levels of transcripts involved in mammary development and differentiation. These data provide evidence for the existence of a multipotent, pregnancy-activated mammary progenitor and suggests that different progenitor populations are responsible for mammary expansion during puberty and pregnancy. Future studies may identify FACS markers for purification of pregnancy-activated progenitors and further elucidate the role of different mammary cell types during pregnancy.
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Nakano, Ichiro. "Maternal embryonic leucine zipper kinase (MELK) regulates multipotent neural progenitor proliferation". Kyoto University, 2008. http://hdl.handle.net/2433/135920.
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Yoshikawa, Katsuhiro. "Multipotent stem cells are effectively collected from adult human cheek skin". Kyoto University, 2013. http://hdl.handle.net/2433/174817.
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Mitutsova, Violeta. "Cellules souches du muscle squelettique : étude d'une population capable de différenciation multipotente". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTT025/document.
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L'utilisation des cellules souches est une approche prometteuse pour le traitement des maladies dégénératives neuromusculaires. De nombreuses études portent actuellement sur les cellules souches embryonnaires (ES) et les cellules pluripotentes induites par reprogrammation (IPs) dont l'utilisation en médecine régénérative reste sujette à caution à cause du potentiel de ces cellules à former des tératomes. Des lors, aussi bien les ES que les IPs nécessitent une différenciation vers un type cellulaire précis. Cette différenciation peut mener à des risques supplémentaires tels que la dérive génique ou diverses sources de contamination.Le muscle squelettique adulte, avec sa grande plasticité et capacité régénératrice, contient une population de cellules souches qui est spécifique de ce compartiment tissulaire et qui a été isolée et étudiée au laboratoire. Les cellules souches du muscle squelettique adulte: skeletal Muscle-Derived Stem Cells, MDSC, repeuplent et réparent en quelques jours le muscle squelettique lésé avec une haute efficacité, même en présence des cellules satellites endogènes. (Arsic et al Exp. Cell Res. 2008). Le laboratoire d'accueil a entrepris de caractériser cette population cellulaire, en particulier par son origine histologique, de tester le potentiel de réparation tissulaire de ces cellules transplantées dans des modèles murins, et de déterminer la bio-distribution de ces cellules en vue d'utilisation thérapeutique.Mon travail de thèse s'est intéressé à cette population de cellules souches issues du muscle qui ont une propriété commune : la faible adhérence au substrat. La faible adhérence est une propriété très intéressante car en plus de définir des cellules plus proches de l'état pluripotent, cette propriété leur confère une grande capacité de migration. Ces cellules seraient donc plus facilement utilisables en médecine régénératrice. Dans cette perspective il est intéressant de disposer de cellules souches multipotentes qui pourrait se comporter comme des cellules pluripotentes en terme de capacité régénératrice, mais sans les inconvénients de ces dernières à savoir ; risque tératogène et prolifération incontrôlée, et manipulation des cultures cellulaires longues et couteuses.Au début de ma thèse je me suis donc intéressée aux différentes populations de cellules présentes dans le muscle et je me suis concentrée sur différents marqueurs connus chez les cellules souches, dont la présence a été établie chez différentes cellules souches y compris chez les cellules souches dérivées du muscle squelettique, mais pas clairement identifiés d'un point de vue histologique. Les cellules souches du muscle expriment le facteur de pluripotence Sox2, mais aussi des marqueurs d'immaturité tels que BCRP1/ABCG2, Sca-1 et SSEA1. J'ai examiné leur potentiel de différenciation in vitro en plusieurs lineages tels que des cellules cardiaques spécifiques (dites pacemakers), des cellules productrices d'insuline et des cellules qui présentent des marqueurs neuronaux. Je me suis également concentrée sur les possibles applications thérapeutiques grâce à l'utilisation de modèles génétiques murins et notamment dans les cas de problèmes du rythme cardiaque, et du diabète insulinodépendant. Pour ces études in vivo du potentiel réparateur des MDSC on procède à une simple injection des cellules souches dérivées du muscle squelettique (MDSC). Le fait de retrouver des MDSC injectées dans les organes cibles des souris modèles pose aussi la question de la biodistribution de ces cellules dans l'organisme. J'ai donc consacré plus d'un an de mon financement doctoral pour examiner cette biodistribution et montré un recrutement ciblé dès 48h après injection, vers les organes ou tissus lésésThe use of stem cells is a promising approach for the treatment of neuromuscular degenerative diseases. Many studies currently focus on embryonic stem cells (ES) and induced pluripotent stem cells (IPs) for use in regenerative medicine. But some problems remain for their use in cell therapy in particular the potential of these cells to form teratomas. This problem requires both ES and IPs to be differentiated towards a specific cell type. Such induction of differentiation can lead to additional risks such as genetic drift or various sources of contamination.The adult skeletal muscle, has a high plasticity and regenerative capacity, it contains a stem cell population that is specific for muscle, and has been isolated and studied in the laboratory. Adult skeletal Muscle-Derived Stem Cells, MDSC repopulate and repair damaged skeletal muscle with high efficiency in a few days, even in the presence of endogenous satellite cells. (Arsic et al Exp. Cell Res. 2008). The host laboratory is characterizing this cell population and its histological identity and testing the tissue repair potential of transplanted MDSC in mouse models, as well as their bio-distribution for therapeutic use.My thesis work addressed the study of this stem cells population isolated from skeletal muscle showing low adhesion to substrate. Poor/low adherence is an interesting property because in addition to be defined as closer to the pluripotent state, this property is associated with a higher migration capability. This population of muscle stem cells should be easier to use than pre-differentiated stem cells in regenerative medicine. In this perspective it is interesting to use multipotent stem cells that are close to pluripotent cells in terms of differentiation and regenerative capacity, but without the inconveniencies like teratogenic risk and uncontrolled proliferation, as well as expensive and time-consuming cell culture.At the beginning of my thesis I was interested by the different populations of cells present in muscle and I focused my work on known markers of stem cells, whose presence has been established in skeletal muscle, but not clearly identified histologically. Muscle stem cells expressed the pluripotency factor Sox2, but also markers, such as BCRP1/ABCG2, Sca-1 and SSEA1. I have examined the potential of MDSC to differentiate in vitro into several cell types such as cardiac pacemaker-like cells, insulin-producing cells and cells that exhibit neuronal markers. I also focused on the possible therapeutic applications of MDSC, particularly in the case of heart rhythm problems and in the case of insulin-dependent diabetes. For these in vivo studies of the repair potential of MDSC, a single systemic injection is carried out in mouse models of the diseases. The histological recovery of injected MDSC into target organs also raises the question of the biodistribution of MDSC in the body. Therefore I spent more than a year of my doctoral thesis to address this issue and showed a targeted recruitment of MDSC to injured tissue or organs within 48h of their systemic injection
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Hjerling-Leffler, Jens. "Sensory neurons: stem cells and development /". Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-667-0/.
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Li, Yueying. "Vieillissement des cellules stromales mésenchymateuses de la moelle osseuse : implications en médecine régénérative". Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0099/document.
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Grâce à leurs propriétés de différenciation, les cellules stromales mésenchymateuses (CSM) constituent aujourd’hui un outil en médecine régénérative. La moelle osseuse reste une des plus utilisées. Une diminution de la capacité de prolifération et de différenciation des CSM-MO, au cours des passages, a été montrée. En parallèle, certaines études montrent que l'impact de l'âge du donneur sur les propriétés de CSM-MO reste encore controversé. Le but de notre étude était de mieux comprendre l'effet de l'âge du donneur mais aussi des passages en culture sur la capacité de prolifération et de différenciation des CSM de moelle osseuse. Les échantillons ont été séparés en 4 groupes en fonction de l’âge des donneurs (<20 ans; 20-40 ans; 40-60 ans; >60 ans) et les analyses ont été réalisés lors de la culture de cellules pendant 5 passages. Les résultats obtenus montrent que la capacité de prolifération de CSM-MO obtenues à partir de donneurs jeunes est supérieure à celle de cellules des donneurs âgés. De plus, cette capacité de prolifération diminue en fonction des passages en culture. En parallèle, la capacité des cellules à former des colonies, mesurée par le test CFU-F, diminue légèrement en fonction de l’âge des donneurs mais de façon importante en fonction du passage. Enfin, la capacité de différenciation des CSM-MO vers les trois types cellulaires étudiés, diminue en fonction des passages de cellules mais également en fonction de l’âge des donneurs. Notre étude montre que les propriétés des CSM issues de moelle osseuse sont modifiées lors de l’amplification in vitro mais aussi en fonction de l’âge des donneursToday with their properties of differentiation into specific cells types, mesenchymal stromal cells (MSC) can be used in regenerative medicine. Bone marrow (BM) is the better characterized one. The researchers have proven that with increasing passage number in culture the proliferation and differentiation potential of MSC decrease. In parallel many researchers have showed the impact of donor age on MSC properties remains controversial. The aim of our study was to better understand the effect of donor age but also culture passages on the proliferation and differentiation ability of bone marrow mesenchymal stromal cells. The samples were separated into 4 groups depending on the donor age (<20 years; 20-40 years; 40-60 years; > 60 years) and The samples were cultured for 5 passages. The results obtained show that the MSC proliferative capacity obtained from young donors is greater than that of cells from older donors. In addition, the proliferative capacity decreases with increasing passage number in culture. In parallel, the ability of colony-forming unit-fibroblast, measured by the CFU-F assay, decreases slightly depending on the age of the donors but significantly depending on the passage. Finally, the MSC differentiation ability decreases according to the passage of the cells but also depending on the donor age. Our study shows that the properties of bone marrow derived MSC are modified not only during amplification in vitro but also in terms of donor age
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Ferré, François. "Isolation et caractérisation des cellules souches gingivales : étude de leur potentiel multipotent". Phd thesis, Université René Descartes - Paris V, 2013. http://tel.archives-ouvertes.fr/tel-01017172.
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Les capacités de cicatrisation de la gencive en font un modèle de régénération tissulaire naturelle. Ces capacités sont liées en grande partie à l'activité des fibroblastes. Composante cellulaire principale du tissu conjonctif gingival, ils sont au cœur de la régulation des réponses inflammatoires et des processus de cicatrisation. Nous avons supposé que ce tissu pouvait contenir des cellules souches, pouvant expliquer en partie, ces capacités de réparation. Au cours de cette thèse, nous avons pu mettre en évidence la présence de cellules souches mésenchymateuses aux propriétés communes avec les cellules souches adultes dérivées des crêtes neurales. Ces cellules expriment des marqueurs spécifiques des cellules souches et des crêtes neurales. Par ailleurs, elles présentent des capacités d'auto-renouvellement et de multipotence. Elles sont, en effet, capables de se différencier en adipocytes, ostéocytes et chondrocytes. Nous nous sommes plus particulièrement intéressés à la différenciation chondro/endochondrale. La culture des cellules, sous forme de sphères en suspension, a permis de mettre en évidence leurs capacités de différenciation en tissus cartilagineux et articulaires. Elles s'organisent spontanément en plusieurs types cellulaires différents, générant notamment des chondrocytes hypertrophiques et des synoviocytes selon leur localisation au sein des sphères et du milieu de culture utilisé. Le comportement de ces cellules soumises à ces conditions a permis de montrer leurs facultés à reproduire, in vitro, des processus proches de ceux retrouvés au cours du développement. Ces résultats permettent une meilleure compréhension des phénomènes de différenciation des cellules souches adultes, ouvrant ainsi de nouvelles perspectives pour des applications en thérapie cellulaire articulaire et osseuse.
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Ahmed, Muhammad A. "Exploring the impact of hypoxia mimetic agents on multipotent stem cell biology". Thesis, Keele University, 2018. http://eprints.keele.ac.uk/4532/.
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Oxygen is an important molecule in life and is essential for a broad spectrum of physiological reactions that include, but are not restricted to, cell metabolism, respiration and growth. Under physiological conditions, oxygen levels vary from one tissue to another ranging from 0.002% to 10% and substantially lower than the atmospheric level of 21 % O2. Hypoxia is defined as a state of reduced O2 supplied to cells or tissues when compared to their normal physiological levels. Hypoxia mimetic agents (HMAs) are chemical used to induce pharmacological hypoxia without affecting environmental oxygen levels per se. The name HMA is routinely applied as these agents will activate the family of transcription factors which respond to reduced oxygen availability, Hypoxia Inducible Factors (HIF), which is taken as a surrogate indicator for hypoxia. These agents have been proposed as a cheaper alternative to engineered oxygen control measures including tri-gas incubators and workstation approaches. Multipotent stem cells (e.g. neuronal PC12 and human mesenchymal stem cells (hMSCs)) due their ability to differentiate into various cell types provide a means to develop better understanding of tissue development, repair, and protection. In addition, they provide better therapeutic perspectives and opportunities for the treatment of many diseases. Physiological oxygen plays a key role in the maintenance of cellular proliferation, behaviour and biology both in vivo and when mimiced in vitro. Physiological oxygen and hypoxia are routinely confused creating additional complexity in defining the role of oxygen in cell behaviours. This work has therefore evaluated the role of a panel of well-established HMAs (CoCl2, DFO, DMOG) and new agent (IOX2) vs. different reduced oxygen culture conditions. PC12 and hMSCs were both used to examinine the roles of HMAs on proliferation, metabolic activity, HIFs expression, nitroreductase activity, oxidative stress, apoptosis, death/necrosis and mitochondrial dynamic (burden, action potential and genome copy number) in comparison to physiological normoxia and intermittent hypoxia. HMAs induced HIF expression, apoptosis, trapped cell at G0/G1 phase and induced both ROS formation and nitroreductase activity in a manner that was not consistent with a reduced oxygen culture condition alone. Mitochondrial burden, mitochondrial action potential, and mitochondrial genome number also changed in response to HMA exposure in a manner that was indenependent of the oxygen culture conditions tested. In summary, HMAs do not provide an accurate replication of engineered oxygen control measures in PC12 and hMSC biology. This is reflected in biological alterations impacting on cell yield, behaviour and biology.
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de, Almeida Rocha Ponzoni Raquel. "Raman spectroscopy studies of multipotent stromal cells differentiation for bone engineering application". Thesis, University of York, 2017. http://etheses.whiterose.ac.uk/18435/.
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Raman spectroscopy (RS) is a label-free method based in the inelastic scattering of laser-light and can be used non-destructively to provide a biomolecular fingerprint of cells. Mesenchymal stromal cells (MSCs) are known for their heterogeneity and, unlike other stem cells, lack a unique marker, thus compromising their application in regenerative medicine. In this work, RS was investigated for its capacity to discriminate MSCs subpopulations, whilst still providing markers of their function. Four immortalised clonal MSC lines, which express the same surface proteins, have contrasting differentiation capacities and were not totally discriminated by global gene expression analyses, were investigated. Air-dried and live cell experiments were performed, as well as the induction of one cell line into ostegenesis and adipogenesis. Relative differences between proteins and DNA/RNA provided the discrimination of the undifferentiated MSCs towards their differentiation competence. Raman spectroscopy also showed clear progression of the adipogenic differentiation. During osteogenesis, the MSCs formed mineralised nodules with an architecture similar to native human bone. The RS investigation of these MSCs showed that the obtained Raman markers could be used to predict differentiation competence in undifferentiated cells and then, followed throughout osteogenesis.
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Bown, Andre B. J. "The Utilization of Multipotent Mesenchymal Stromal Cell Transplantation to Improve Fascia Repair". Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1376390936.
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Rondeau, Vincent. "Rôle de la désensibilisation de CXCR4 dans la spécification lympho-myéloïde des progéniteurs hématopoïétiques multipotents. Lymphoid differentiation of hematopoietic stem cells requires efficient Cxcr4 desensitization New method to obtain lymphoid progenitors CXCR4-driven mitochondrial metabolic pathways shape the lympho-myeloid fate of hematopoietic multipotent progenitors". Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASQ022.
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Les cellules souches et progéniteurs hématopoïétiques (CSPHs), incluant les progéniteurs multipotents (MPPs), sont responsables de la production des cellules immunes circulantes. Ils résident dans la moelle osseuse (MO) au sein de structures spécialisées, les niches endostéale et (péri)-vasculaire, qui régulent la spécification et l'engagement lymphoïde versus myéloïde des CSPHs. Dans la MO, le couple formé par la chimiokine CXCL12 et l’un de ses récepteurs, CXCR4, exerce un rôle clé dans la régulation de la rétention et la quiescence des CSPHs. Ces processus sont dérégulés dans le Syndrome WHIM (SW), une maladie immuno-hématologique rare liée à des mutations autosomiques dominantes du gène codant CXCR4, qui altèrent la désensibilisation du récepteur et conduisent à un gain de fonction en réponse à CXCL12. Cliniquement, le SW se caractérise notamment par une profonde leucopénie circulante qui affecte les lignages lymphoïde et myéloïde et dont les mécanismes restent à déterminer. Grâce à un modèle murin génétiquement modifié du SW et à l'accès à des prélèvements biologiques de patients atteints du SW, nous avons testé l'hypothèse que la lymphopénie circulante associée au SW résultait de défauts hématopoïétiques dans la MO. Nous avons révélé un rôle clé de la désensibilisation de CXCR4 dans la différenciation lymphoïde des CSPHs et identifié les MPPs comme étant le stade défectueux dans le SW. La divergence entre les lignages lymphoïde et myeloïde se produit précisément à ce stade au sein duquel règne une hétérogénéité : les MPP2/3 sont biaisés myéloïde et les MPP4 sont orientés lymphoïde. Notre compréhension de la façon dont les signaux extrinsèques (niches) et intrinsèques aux MPPs déterminent leur devenir lymphoïde versus myéloïde est encore parcellaire. Dans ce contexte, l’objectif de ma thèse a été de déterminer si et comment la signalisation de CXCR4 régule la dépendance énergétique des MPPs et à comprendre comment les voies métaboliques façonnent leur spécification lympho-myéloïde. Dans la MO des souris porteuses de la mutation gain de fonction de Cxcr4, nous avons observé une diminution du nombre de MPP4 qui contrastait avec l'augmentation des MPP2/3. L’analyse de prélèvements médullaires de patients a également permis de rapporter une diminution de la fréquence des progéniteurs lymphoïdes et une augmentation de celle des progéniteurs myéloïdes. Chez la souris mutantes, ce biais myéloïde du compartiment de MPPs s'avèrait associé à une expansion anormale et une reprogrammation moléculaire et métabolique des MPP4. Fait marquant, un traitement chronique par l’AMD3100, un antagoniste de CXCR4, permettait de normaliser le nombre de MPP4 dans la MO, de restaurer leurs propriétés métaboliques, et de corriger la lymphopénie des souris mutantes. Par conséquent, nos résultats suggèrent que l’axe CXCL12/CXCR4 est requis au maintien du potentiel lymphoïde des MPP4 au travers de la modulation de leur activité métabolique mitochondrialeHematopoietic stem and progenitor cells (HSPCs), including the multipotent progenitors (MPPs), are responsible for replenishing immune cells. They reside in bone marrow (BM) endosteal and (peri)-vascular niches, which provide all cellular and molecular components required for their lifelong maintenance and fate. Among them, the CXCL12 chemokine and one of its receptor, CXCR4, exert a dominant role in promoting HSPC retention and quiescence. These processes are deregulated in the WHIM Syndrome (WS), a rare immunodeficiency caused by inherited heterozygous autosomal gain-of-function CXCR4 mutations that affect homologous desensitization of the receptor. Clinically, WS is notably characterized by severe, chronic circulating lymphopenia whose mechanisms remain to be elucidated. Using a mouse model carrying a naturally occurring WS-linked Cxcr4 mutation as well as human BM and blood samples, we explored the possibility that the lymphopenia in WS originates from defects at the HSPC level in BM. We reported that Cxcr4 desensitization is required for lymphoid differentiation of HSPCs and further identified the MPP stage as defective in mutant mice. The divergence between lymphoid and myeloid lineages occurs at the MPP stage, which is composed of distinct subpopulations, i.e., MPP2 and MPP3 are reported as distinct myeloid-biased MPP subsets that operate together with lymphoid-primed MPP4 to control blood leukocyte production. Our understanding of how cell-extrinsic niche-related and cell-intrinsic cues drive the lymphoid versus myeloid fate decision of MPPs is still fragmentary. Therefore, my PhD project aimed at determining whether and how CXCR4 signaling regulates bioenergetics demands of MPPs and at understanding how these metabolic pathways shape the lympho-myeloid fate of MPPs. We unraveled a myeloid skewing of the HSPC compartment in BM of WS mice and patients. In mutant mice, this partly relied on the contraction of the MPP4 pool and on cell-autonomous molecular and metabolic changes that reprogramed MPP4 away from lymphoid differentiation. Interestingly, chronic treatment with the CXCR4 antagonist AMD3100 normalized mitochondrial metabolism and fate of MPP4, while correcting circulating lymphopenia in WS mice. This study provides evidence that CXCR4 signaling acts as an essential gatekeeper for integrity of the mitochondrial machinery, which in turn controls lymphoid potential of MPP4
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Eydt, Carina [Verfasser]. "Equine multipotente, mesenchymale Stromazellen (MSCs): Optimierung der Gewinnung, Expansion und Kultivierung / Carina Eydt". Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2016. http://d-nb.info/1124565647/34.
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Mayeuf, Alicia. "Choix du destin cellulaire des progéniteurs multipotents du somite, chez l'embryon de souris". Paris 6, 2013. http://www.theses.fr/2013PA066495.
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La partie dorsale du somite, le dermomyotome contient des progéniteurs multipotents Pax3+ donnant naissance à de nombreux types cellulaires : musculaires, dermiques, endothéliales, murales et adipocytes bruns. Le but de ma thèse été de comprendre les mécanismes associés aux choix de destins cellulaires chez l’embryon de souris. Nous avons dans un premier temps montré que la voie de signalisation Notch favorise l’entrée des progéniteurs multipotents vers un destin vasculaire plutôt que myogénique, en agissant sur l’équilibre génétique Pax3 :Foxc2. Afin de déterminer si Foxc1, l’homologue de Foxc2, est aussi impliqué dans ce mécanisme, nous avons spécifiquement délété ces deux gènes dans les progéniteurs Pax3+. Ceci engendre de nouveaux phénotypes que nous documentons dans cette étude. Le nombre de cellules vasculaires est réduit, tout comme l’est le nombre de cellules myogéniques du membre. Différentes hypothèses sont proposées pour expliquer ce défaut. Foxc2 est un facteur également impliqué dans la différenciation du tissu adipeux brun. Nous avons étudié le développement de ce tissue au cours du développement et proposons un modèle selon lequel il se développe en deux étapes, la première étant le développement d’une « masse adipogénique indifférenciée » et la seconde correspondant à la différenciation des adipocytes bruns. Des approches de perte et gain de fonction nous ont permis de montrer que Foxc1 et Foxc2 semblent jouer un rôle dans le contrôle de la fonction mitochondriale au cours de la différenciation des adipocytes bruns, et ce même rôle pourrait être joué par Foxc1 dans les fibres musculaires oxydatives chez l’adulte où Foxc1 est spécifiquement expriméThe dorsal part of the somite, the dermomyotome contains multipotent Pax3+ progenitors, which give rise to different cell types such as skeletal muscle, dermal, endothelial, mural and brown adipose cells. The aim of this thesis was to understand mechanisms underlying cell fate decisions in this context in the mouse embryo. We have first shown that the Notch signaling pathway directs multipotent progenitors towards a vascular instead of a myogenic fate, by acting on the Pax3 :Foxc2 genetic equilibrium. To determine if Foxc1, the homologue of Foxc2, is also implicated in this mecanism, we have conditionally deleted both genes in Pax3+ progenitors. We document new phenotypes, including a reduction in vascular, cells, notably endothelial cells in the forelimb, where, surprisingly myogenic cells are also absent, leading to a number of possible hypotheses. Foxc2 is also implicated in the differentiation of brown adipose tissue, which we show is a derivative of Pax3+ cells in the dermomyotome. We have studied the development of this tissue in the embryo and propose a model in two steps, with initial formation of an “undifferentiated adipogenic mass” which subsequently differentiates into brown adipocytes. Gain and loss of function approaches suggest that Foxc1/2 play a role in the control of mitochodrial function during the differentiation of brown adipocytes in the embryo. This role may also be played by Foxc1 in the slow fibers of skeletal muscle where it is specifically expressed in the adult
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Gadepalli, Venkat Sundar. "ISOLATION AND CHARACTERIZATION OF MULTIPOTENT LUNG STEM CELLS FROM p53 MUTANT MICE MODELS". VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3644.
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Recent advances in understanding lung biology have shown evidence for the existence of resident lung stem cells. Independent studies in identifying and characterizing these somatic lung stem cells have shown the potential role of these cells in lung repair and regeneration. Understanding the functional characteristics of these tissue resident stem/progenitor cells has gained much importance with increasing evidence of cancer stem cells, cells in a tumor tissue with stem cell characteristics. Lung cancer is most commonly characterized by loss of p53 function which results in uncontrolled cell divisions. Incidence of p53 point mutations is highest in lung cancer, with a high percentage of missense mutations as a result of tobacco smoking. Certain point mutations in p53 gene results in its oncogenic gain of functions (GOF), with enhanced tumorigenic characteristics beyond the loss of p53 function. However, there are no available data on characterization of lung stem cells carrying GOF mutations and correlating them with those of normal stem cells, in this study, for the first time we show that percentage of Sca-1 expressing subpopulation is significantly higher in the lungs of mice carrying p53 GOF mutations than those in lungs isolated from p53+/+ wild type mice. Further, we successfully established lung cells differentially expressing two cell surface markers, Sca-1 and PDGFR-α, with results demonstrating existence of different subpopulations of cells in the lung. Results from our project demonstrate the importance of p53 GOF mutations as correlated with specific lung cell subpopulations.
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Traveset, Martínez Laia 1992. "New insights into transcription that preserve hematopoietic stem cell homeostasis". Doctoral thesis, Universitat Pompeu Fabra, 2020. http://hdl.handle.net/10803/670105.
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Maintenance of steady-state and stress-adapted hematopoiesis depends on the fitness of hematopoietic stem and progenitor cells (HSPCs) in the bone marrow. Hematopoietic stem cells (HSCs) can adapt to stress by expanding their numbers and increasing the output of blood cells. This dynamic and highly complex process needs to be fully regulated in order to maintain a balance between the differentiation of HSCs and the need to keep a constant pool of HSCs. However, the molecular machinery in charge of this tight regulation has yet to be fully characterized. HSCs represent a small proportion inside the HSPC compartment, which also includes the immediate progeny of HSCs, the multipotent progenitors (MPP). MPPs are a cell population that retain full lineage potential yet have a limited self-renewal capacity compared to HSC.
In this Thesis we explore a novel mechanism important for the maintenance and protection of HSC function under stress. We have characterized HSC homeostasis and function upon serial transplantation, after myeloablative injury and after a protocol of total body irradiation. We present in vivo results elucidating a new transcription mechanism involved in the maintenance of the viability and self-renewal capacity of HSCs that restrains its differentiation to MPPs, in situations in which the hematopoietic system must keep constant the stem cell reservoir in order to avoid HSC exhaustion.El manteniment de l'hematopoesi en condicions basals i en situacions d’estrès depèn de l'aptitud de les cèl·lules mare i progenitores hematopoètiques (HSPCs) de la medul·la òssia. Les cèl·lules mare hematopoètiques (HSC) són capaces d’adaptar-se a l’estrès mitjançant l'ampliació dels seus nombres i l'augment de la producció de cèl·lules sanguínies. Aquest procés, dinàmic i molt complex, ha d'estar totalment regulat per tal de mantenir un equilibri entre la diferenciació de les HSCs i la necessitat de mantenir un nombre constant de HSCs. No obstant això, la maquinària molecular encarregada d'aquesta regulació no ha estat encara completament caracteritzada. Les HSCs tan sols representen una petita proporció dins del compartiment de HSPCs el qual també inclou la progènie immediata de les HSCs, els progenitors multipotents (MPP). Els MPPs són una població cel·lular que conserva el potencial de llinatge complet, però que presenta una capacitat d'autorenovació limitada en comparació amb les HSCs. En aquesta tesi explorem un nou mecanisme important pel manteniment i la protecció de la funció de les HSCs sota estrès. Hem caracteritzat com la cèl·lula mare hematopoètica funciona després d’un trasplantament en sèrie, després d’una lesió de mielosupressió i després d’un protocol d’irradiació total. Per tant, presentem resultats in vivo que diluciden un nou mecanisme transcripcional implicat en el manteniment de la viabilitat i la capacitat d’autorenovació de les HSC i que restringeix la seva diferenciació cap a MPPs, en situacions en què el sistema hematopoètic ha de mantenir constant el dipòsit de cèl·lules mare per tal d’evitar el seu esgotament.
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Viana, Gaza Maria Elisabet. "Disseny i síntesi de nous compostos multipotents per al tractament de la malaltia d’Alzheimer". Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/110463.
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El principal factor desencadenant de la neurodegeneració que caracteritza la malaltia d’Alzheimer (MA) és el pèptid β-amiloide (Aβ). La formació incrementada d’aquest pèptid i la seva agregació es troben a l’inici d’una cascada de processos neurotòxics que culminen amb una disfunció neuronal generalitzada i mort neuronal. Actualment, es troben en fase clínica diferents candidats a fàrmacs anti-Alzheimer denominats “modificadors de la malaltia” que van dirigits a inhibir la formació o l’agregació de l’Aβ. S’espera que aquests compostos puguin prevenir o frenar la neurodegeneració de la MA.
L’arsenal terapèutic actual per al tractament de la MA continua estant dominat per un grup de fàrmacs que van estar desenvolupats per a tractar la seva simptomatologia, la qual apareix com a conseqüència de dèficits de diferents neurotransmissors, especialment d’acetilcolina (ACh), al sistema nerviós central. Concretament, quatre dels cinc fàrmacs actualment comercialitzats per al tractament de la MA són un grup d’inhibidors de l’enzim acetilcolinesterasa (AChE), enzim responsable de la hidròlisi de l’ACh.
Recentment s’ha demostrat que l’AChE es pot unir a l’Aβ accelerant la seva agregació, augmentant-ne la neurotoxicitat i promovent el deteriorament cognitiu. A través del denominat lloc perifèric, el qual es troba a l’entrada d’una gorja catalítica d’uns 20 Å de longitud, al fons de la qual es troba el lloc catalític de l’enzim. Així, el bloqueig simultani amb ambdós llocs d’unió (actiu i perifèric) ha portat al desenvolupament dels denominats inhibidors d’AChE de lloc d’unió dual, els quals són candidats molt prometedors a fàrmacs anti-Alzheimer amb potencial per modificar positivament el curs de la malaltia.
D’altra banda, degut al caràcter multifactorial de l’etiologia de la MA s’està començant a considerar el desenvolupament de nous compostos multipotents capaços d’interaccionar amb diferents dianes biològiques involucrades en la malaltia com a única via per a aconseguir incidir eficientment sobre la malaltia, com ara, l’estrès oxidatiu degut a la sobreproducció d’espècies reactives d’oxigen (ROS). S’ha demostrat que els compostos quelants d’ions metàl•lics són capaços d’inhibir la producció de ROS i s’està considerant la utilització d’antioxidants naturals contra processos en els quals està implicat l’estrès oxidatiu, com és el cas de la MA.The main factor triggering the process of neurodegeneration characteristic of Alzheimer's disease (AD) is the so-called β-amyloid peptide (Aβ). The increased formation of this peptide and its aggregation are placed at the beginning of a cascade of neurotoxic processes culminating in widespread neuronal dysfunction and death. Currently, there are several "disease-modifying" anti-Alzheimer drug candidates in clinical trials aimed at inhibiting the formation or aggregation of Aβ. It is expected that these compounds can prevent or slow the neurodegeneration of AD. The current treatment available for the treatment of AD is still dominated by a group of drugs that were developed to treat its symptoms, which appear as a result of the decrease in the production of various neurotransmitters, particularly acetylcholine (ACh) at the central nervous system. Consequently, the use of cholinomimetic agents capable to compensate this deficit should reduce cholinergic symptoms of AD. In fact, four out of the five drugs currently marketed for the treatment of AD are a group of inhibitors of the enzyme acetylcholinesterase (AChE), the enzyme responsible for the hydrolysis of ACh at the synapses, which increase levels of the neurotransmitter, thus reducing the symptoms of AD. Recently, it has been demonstrated that the enzyme AChE can bind to Aβ accelerating its aggregation, increasing the neurotoxicity and promoting cognitive decline. The binding site of AChE to Aβ is the so-called peripheral site, which is located at the entrance of a catalytic gorge of about 20 Å length, at the bottom of which the catalytic site of the enzyme is placed, where the hydrolysis of ACh takes place. Thus, the blockade of the peripheral site of AChE should lead to an inhibition of Aβ aggregation and of the neurodegenerative cascade. In addition, the particular architecture of the enzyme where the active and peripheral sites are separated but close enough to allow a molecule to simultaneously interact with the two binding sites has led to the development of dual binding site AChE inhibitors, which are very promising anti-Alzheimer drug candidates expected to positively alter the course of disease. Moreover, due to the multifactorial nature of the etiology of AD, development of multipotent compounds capable of interacting with different biological targets involved in the disease is beginning to be considered as the only way to achieve efficient impact on the course of the disease. Aβ aggregation plays a crucial role in the pathogenesis of AD, inducing processes in the neurodegenerative cascade and oxidative stress due to overproduction of reactive oxygen species (ROS). It also appears that the Cu2+ and Fe3+ ions are capable of generating ROS, after binding to the Aβ For these reasons, the metal ions and oxidative stress are interesting targets to modulate by multipotent anti-Alzheimer drug candidates. Thus, it has been shown that the compounds capable of chelating metal ions are able to inhibit the production of ROS and the use of natural antioxidants is also being considered to block the oxidative stress involved in Aβ. The aim of the present PhD is to develop multipotent compounds capable to interact with different biological targets involved in AD, namely cholinesterases, Aβ and oxidative stress, in order to block its neurodegenerative cascade.
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Grau, Vorster Marta. "Development and characterisation of advanced cell therapies based on multipotent mesenchymal stromal cells and virus-specific Tlymphocytes". Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/669379.
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El desenvolupament de noves teràpies s’està duent a terme arreu del món per poder fer front a les necessitats clíniques que actualment no disposen de tractament. En particular, els avenços en productes medicinals de teràpia avançada (ATMP) són una gran promesa per al tractament de malalties sense altres opcions terapèutiques. Tanmateix, els investigadors i les autoritats reguladores que implementen aquestes teràpies lluiten per estandarditzar tant els protocols com els productes finals. Entre els reptes s’inclouen l’elevada intervariabilitat de donants i mecanismes d’acció complexos. A més, és necessari demostrar l’activitat biològica d’aquestes teràpies mitjançant assajos de potència.
Aquesta tesi consisteix en el desenvolupament i caracterització de dos ATMP basats en cèl·lules multipotents estromals mesenquimals (MSC) i cèl·lules T específiques de virus (VST).
D'una banda, s’ha fet l’avaluació d'un test de potència i identitat per la producció de MSC aïllades de la gelatina de Wharton (WJ) i de la medul·la òssia (BM). L’objectiu proposat per MSC era realitzar: a) un assaig de potència per avaluar la capacitat immunomoduladora de les MSC; b) la revisió de l’expressió del HLA-DR pels criteris de definició de les MSC; i c) l'aplicació d’una eina per gestionar el risc. En aquest treball es presenta l’optimització d’un assaig d’immunopotència, validat i aprovat per l’autoritat competent per a l’alliberament de producte. S’ha estudiat l’expressió del HLA-DR, marcador suposadament negatiu, en les BM-MSC de grau clínic. Els resultats van mostrar una correlació entre l’expressió del HLA-DR i els nivells d’IL-17F i IL-33. L'expressió del HLA-DR no va afectar la identitat de les MSC, ni el potencial de diferenciació ni la capacitat immunomoduladora. Per reforçar aquests resultats, es van realitzar estudis interlaboratori obtenint resultats similars. L'ús de suplements basats en sèrum humà o lisat plaquetari no mostrava diferències en l'expressió de HLA-DR en MSC. També es va implementar la gestió de riscos com a eina de qualitat per detectar debilitats d’un bioprocés. Aquests enfocaments s’han dut a terme per MSC en assajos clínics.
D'altra banda, es va realitzar el desenvolupament d'un protocol d'expansió ex vivo de VST. La teràpia amb VST està destinada a pacients immunocompromesos, susceptibles de patir una reactivació o infecció de novo de l’herpesvirus entre d’altres. És el cas del citomegalovirus (CMV), que pot produir una infecció lleu en individus sans, però té una elevada morbiditat i mortalitat en individus immunocompromesos. Els medicaments antivirals disponibles poden produir toxicitat i no sempre són efectius. La immunoteràpia adoptiva ofereix una alternativa als pacients en una situació crítica i sense altres opcions terapèutiques. Per satisfer aquesta demanda es va elaborar un protocol de fabricació de VST fàcilment transferible als estàndards farmacèutics. Amb el mètode proposat, després d’un cocultiu de 14 dies amb cèl·lules dendrítiques polsades amb pp65, es van obtenir un gran nombre de VST. El cultiu es basava en la tecnologia G-Rex i es suplementava amb IL-2, IL-7, IL-15, i anticossos anti-CD3 i anti-CD28. El producte final es va caracteritzar àmpliament i estava format per limfòcits T CD4+ i CD8+, on la subpoblació majoritària corresponia a les cèl·lules T efectores de memòria, població coneguda per proporcionar una funció efectora. Cal destacar la citotoxicitat de les cèl·lules expandides específicament enfront al pp65. Els estudis d’al·loreactivitat amb HLA totalment incompatibles, van mostrar una lisi cel·lular per sota del 5%. En resum, s’ha descrit un protocol transferible a les normes de correcta fabricació actuals i un producte segur i eficaç in vitro, funcional després de la descongelació. El darrer fet, facilitaria la generació d’un banc al·logènic de VST. Les perspectives de futur inclourien la fabricació de cèl·lules T específiques per a múltiples virus.Innovative therapies are being developed worldwide to tackle unmet clinical needs. In particular, progress in advanced therapy medicinal products (ATMP) has shown great promise for the treatment of diseases with no other option available. However, researchers and regulatory authorities deal with the sophisticated nature of these medicines, and struggle to standardise both production protocols and final product formulation. Challenges related to the living nature of these products include high donor intervariability and complex mechanisms of action, which are sometimes not completely understood. Additionally, these newly therapies need to demonstrate biological activity with potency assays. This dissertation comprises the development and characterisation of two different ATMP based on multipotent mesenchymal stromal cells (MSC) and virus-specific T cells (VST). On the one hand, assessment of identity and potency for product release of MSC isolated from Wharton’s jelly (WJ) and bone marrow (BM) in the context of current good manufacturing practice (cGMP) production is performed. In this regard, we aimed at proposing: a) a potency assay for assessing immunomodulation capacity of MSC; b) the revision of HLA-DR expression profile for MSC definition criteria; and c) the application of risk management methodologies in the assessment of product quality. The optimisation of an immunopotency assay, validated, and approved by the competent authority for product release is presented. Moreover, other quality attributes of MSC are addressed. Regarding BM-MSC, the apparently random expression of HLA-DR, a marker that was expected negative in expansion cultures of MSC, is studied in clinical grade productions. Our findings showed correlation of HLA-DR expression with levels of IL-17F and IL-33. Expression of HLA-DR did not affect MSC identity, differentiation potential nor immunomodulatory capacity. To further strengthen these outcomes, interlaboratory studies were performed obtaining similar results. Furthermore, the use of either human sera or platelet lysate supplements showed no differences in terms of HLA-DR expression. A risk management assessment methodology was also implemented as a tool for quality by design to detect weaknesses of an established bioprocess involving MSC products already in clinical trials. On the other hand, regarding T lymphocytes, the development of a protocol for ex vivo expansion of VST was performed. VST therapy is intended for immunocompromised patients, which are susceptible of reactivation or de novo infection of herpesviruses among others. This is the case of cytomegalovirus (CMV) that undergoes a mild infection in healthy individuals but has been associated to a high morbidity and mortality in immunocompromised individuals. Unfortunately, available antiviral drugs can produce toxic side effects and are not always effective. Adoptive immunotherapy offers an alternative approach for those patients in a critical situation with no other therapeutic option. Therefore, we developed a protocol for VST scale-up manufacture easily transferable to pharmaceutical standards. Following with the method proposed, we obtained large number of CMV pp65-specific T cells after 14-day co-culture with pp65 pulsed dendritic cells. Culture was based on G-Rex bioreactor technology and supplemented with IL-2, IL-7, IL-15, anti-CD3 and anti-CD28 antibodies. The final product was extensively characterised in terms of identity, purity and potency. VST product was comprised of both CD4+ and CD8+ T lymphocytes, and effector memory T cells represented the major subset, which are known to provide effector function. Most importantly, we successfully demonstrated pp65 specific cytotoxicity of the expanded cells. Interestingly, complete HLA mismatch alloreactivity resulted in less than 5% cell lysis. In summary, a feasible protocol transferable to cGMP was described for an in vitro safe and effective product, which remain functional after thawing, thus providing practical evidence for the generation of an allogeneic third-party bank. Future perspectives would include the manufacture of multivirus-specific T cells.
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Marshall, Gregory Paul. "Neurospheres and multipotent astrocytic stem cells neural progenitor cells rather than neural stem cells /". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010047.
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Thesis (Ph.D.)--University of Florida, 2005.Typescript. Title from title page of source document. Document formatted into pages; contains 97 pages. Includes Vita. Includes bibliographical references.
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Tripathi, Pratibha. "Isolation of multipotent astroglia form the adult stem cell niche and the injured brain". Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-104224.
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MacDonald, Stephen Christopher. "Oligodendrocytes and motoneurons, two cholinergic cell types derived from multipotent spinal neuroepithelial precursor cells". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0016/NQ53066.pdf.
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Maestri, Valentina <1984>. "Design and synthesis of multipotent drugs: application to Alzheimer's disease and benign prostatic hyperplasia". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5280/.
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The aim of this thesis was to synthesize multipotent drugs for the treatment of Alzheimer’s disease (AD) and for benign prostatic hyperplasia (BPH), two diseases that affect the elderly. AD is a neurodegenerative disorder that is characterized, among other factors, by loss of cholinergic neurons. Selective activation of M1 receptors through an allosteric site could restore the cholinergic hypofunction, improving the cognition in AD patients. We describe here the discovery and SAR of a novel series of quinone derivatives. Among them, 1 was the most interesting, being a high M1 selective positive allosteric modulator. At 100 nM, 1 triplicated the production of cAMP induced by oxotremorine. Moreover, it inhibited AChE and it displayed antioxidant properties. Site-directed mutagenesis experiments indicated that 1 acts at an allosteric site involving residue F77. Thus, 1 is a promising drug because the M1 activation may offer disease-modifying properties that could address and reduce most of AD hallmarks.
BPH is an enlargement of the prostate caused by increased cellular growth. Blockade of α1-ARs is the predominant form of medical therapy for the treatment of the symptoms associated with BPH. α1-ARs are classified into three subtypes. The α1A- and α1D-AR subtypes are predominant in the prostate, while α1B-ARs regulate the blood pressure. Herein, we report the synthesis of quinazoline-derivatives obtained replacing the piperazine ring of doxazosin and prazosin with (S)- or (R)-3-aminopiperidine. The presence of a chiral center in the 3-C position of the piperidine ring allowed us to exploit the importance of stereochemistry in the binding at α1-ARs. It turned out that the S configuration at the 3-C position of the piperidine increases the affinity of the compounds at all three α1-AR subtypes, whereas the configuration at the benzodioxole ring of doxazosin derivatives is not critical for the interaction with α1-ARs.
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Li, Zhengdong [Verfasser]. "Influence of surface topographic microstructure on behaviors of multipotent and pluripotent stem cells / Zhengdong Li". Berlin : Freie Universität Berlin, 2018. http://d-nb.info/1171431236/34.
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DePaul, Marc A. "INTRAVENOUS MULTIPOTENT ADULT PROGENITOR CELL TREATMENT DECREASES INFLAMMATION LEADING TO FUNCTIONAL RECOVERY FOLLOWINGSPINAL CORD INJURY". Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1451317702.
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Tanigaki, Kenji. "Notch1 and Notch3 instructively restrict bFGF-responsive multipotent neural progenitor cells to an astroglial fate". Kyoto University, 2001. http://hdl.handle.net/2433/150564.
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Majo, François. "Renouvellement de l'épithélium de la cornée chez les mammifères". Paris 7, 2005. http://www.theses.fr/2005PA077184.
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Ruggiero, Antonella. "Impact of Wnt signalling on multipotent stem cell dynamics during Clytia hemisphaerica embryonic and larval development". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066561/document.
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Le but de ce travail était d’accroitre notre connaissance des mécanismes qui gouvernent la formation, la spécification et la différentiation des cellules souches, à l’aide du modèle métazoaire non-bilatérien Clytia hemisphaerica. Clytia possède une population particulière de cellules multipotentes appelées cellules interstitielles (i-cells). Ces cellules, présentes au cours du développement larvaire et chez la méduse adulte, sont capables de donner naissances a des cellules somatiques et aux gamètes. Chez les bilatériens, la signalisation Wnt/β-caténine (Wntβc) régule les processus développementaux fondamentaux ainsi que la prolifération, la spécification et la différenciation des cellules souches. Mon travail s’est porté sur l’implication de la signalisation Wntβc dans les dynamiques des i-cells. Mes résultats suggèrent que la signalisation Wntβc est impliquée dans la dernière étape de la différenciation de certains neurones, mais pas pour la spécification du destin cellulaire. D’autre part, j’ai aussi observé qu’en condition contrôle, la formation des i-cells est Wntβc-indépendante et probablement entraînée par le héritage de plasma germinatif contenant les ARNm localisées au pôle animal. Cependant, suite à des expériences de microdissection, j’ai observe que la reformation des i-cells dans la moitie végétative des embryons requérait l’activation de la voie Wntβc. En conclusion, deux mécanismes distincts peuvent conduire à la formation des i-cell pendant l'embryogenèse. Globalement, les résultats obtenus ont fourni une meilleure idée de la façon dont i- cellules et leurs dérivés se posent lors de l'embryogenèse et le développement larvaireThe aim of this work was to extend our understanding of the mechanisms regulating stem cell formation, specification and differentiation by studies in the non-bilaterian metazoan model Clytia hemisphaerica. Clytia, like other hydrozoan cnidarians, possess a particular population of multipotent stem cells called interstitial cells (i-cells), present during larval development and in the adult medusa, which are able to give rise both to somatic cell types and to gametes.In bilaterian animals Wnt/β-catenin signalling regulates fundamental developmental processes such primary body axis specification, but also regulates stem cell proliferation, lineage specification and differentiation. I investigated the role of Wnt/β-catenin signalling in i-cell specification and differentiation. The results obtained suggest that Wnt/β-catenin signalling is involved in the last step of differentiation for certain neuronal cell types, but not for somatic cell fate choice. In the second part of my study I investigated the role of Wnt/β-catenin signalling in i-cell formation during embryogenesis. The results indicated that during normal development i-cell formation is Wnt/β-catenin independent and probably driven by inheritance of germ plasm containing localised mRNAs from the egg animal pole. In contrast in embryo re-patterning following embryo bisection, Wnt/β-catenin signalling appears to be necessary for de novo i-cell formation in the absence of germ plasm. Thus two distinct mechanisms can lead to i-cell formation during embryogenesis. Overall the results obtained provided a better picture of how i-cells and their derivatives arise during embryogenesis and larval development
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Koyama, Noriaki. "Investigation of chondrogenic differentiation capability using human orofacial tissue-derived multipotent cells and human iPS cells". Kyoto University, 2013. http://hdl.handle.net/2433/174775.
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SCHISCHMANOV, NICOLA. "New Hypothesis on the Origin of Metastases". Nagoya University School of Medicine, 2013. http://hdl.handle.net/2237/17613.
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Tan, Yuan. "Using induced pluripotent stem cells to establish disease models with neurodegenerative disorders". Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3952490.
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Angstmann, Michael [Verfasser], i Stefan [Akademischer Betreuer] Wölfl. "Characterization of cell-matrix interactions during multipotent mesenchymal stromal cell (MSC) differentiation / Michael Angstmann ; Betreuer: Stefan Wölfl". Heidelberg : Universitätsbibliothek Heidelberg, 2011. http://d-nb.info/1179230140/34.
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Edri, Shlomit. "Date with destiny : genetic and epigenetic factors in cell fate decisions in populations of multipotent stem cells". Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/288380.
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The governance of cell fate decisions during development is a fundamental biological problem. An important aspect of this is how cells exit a multipotent state and choose their fates in a correct manner and proportion. To tackle an aspect of this problem, I have focused on 2 multipotent models: one infinite self-renewal pluripotency in an artificial environment, and the other, bipotent progenitors in the context of the mouse embryo. The first model aimed to explore the effects of chromatin-associated factors on the ability of pluripotent mouse Embryonic Stem Cells (ESCs) to self-renew, via monitoring gene expression heterogeneity of key genes. The second model focused on Neural Mesodermal Progenitors (NMPs), a bipotent cell population found in the Caudal Lateral Epiblast (CLE) of mammalian embryos, which contributes to the spinal cord and paraxial mesoderm. The aim here was to derive NMPs in vitro which exhibit similar gene expression patterns and function like their mouse embryo counterpart and study their renewal and differentiation in detail. The first multipotent model explores the effects of chromatin remodelling on cell fate decisions, specifically investigating the consequences of inhibiting the histone acetyltransferase Kat2a on the ESCs fate. I found first, that the effect of Kat2a inhibition depends on the pluripotent state of the cells; cells in a ground state exhibit a resistance to Kat2a inhibition and maintain their pluripotency, whereas cells in a naïve state experience destabilization of their pluripotency gene regulatory network and shift towards differentiation. Second, that Kat2a inhibition in the naïve state results in a decline in the gene expression noise strength contributed by the promoter activation operation, which suggests that when ESCs become lineage-primed their transcriptional noise is constrained. In the bipotent model, the NMPs are identified as cells coexpressing Sox2 and T/Brachyury, a criterion used to derive NMP-like cells from ESCs in vitro. Comparison between the different NMPs protocols stresses that Epiblast Stem Cells (EpiSCs) are an effective source for deriving a multipotent population resembling the embryo Caudal Epiblast (CE), that generates NMPs. Furthermore, self-organization of this CE-like population, resulted in axially organized aggregates. Exploiting the mouse embryo CLE as a reference shows that EpiSCs derived NMPs, monolayers and aggregates, consist of a high proportion of cells with the embryo's NMP signature. Importantly, studying this system in vitro sheds light on the sequence of events which lead to NMP emergence in vivo. On this basis, I conclude that understanding the initial state of cells at a crossroads is important to reveal the limitations it imposes on the cells fate exploration, hence makes it possible to mimic more precisely the fate decision process in vitro.
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Wu, Shan Ph D. Massachusetts Institute of Technology. "Rational design to control multipotent stromal cell migration for applications in bone tissue engineering and injury repair". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67198.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biological Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 151-162).
Multipotent stromal cells derived from bone marrow hold great potential for tissue engineering applications because of their ability to home to injury sites and to differentiate along mesodermal lineages to become osteocytes, chondrocytes, and adipocytes to aid in tissue repair and regeneration. One key challenge, however, is the scarcity of MSC numbers isolated from in vivo, suggesting a role for biomimetic scaffolds in the cells' ex vivo expansion before reintegration into target tissue. Toward this end, immobilized epidermal growth factor (tEGF) has recently been found to promote MSC survival and proliferation and is a prime candidate to be incorporated into scaffolds to control MSC behavior. To rationally and effectively design scaffolds to drive MSC responses of survival, proliferation, migration, and differentiation, we must first understand these responses and the underlying protein signaling pathways that mediate them. While our knowledge of MSC behavior is limited as a field, MSC migration is particularly less studied despite being critical for tissue and scaffold infiltration. In this thesis, we quantitatively investigate the effects of tEGF and extracellular matrix (ECM) on MSC migration response and signaling. We take a systems level computational view to show a combined biomaterials and small molecule approach to control MSC migration. Cell migration is a delicately integrated biophysical process involving polarization and protrusions at the cell front, adhesion and translocation of the cell body through contractile forces, followed by disassembly of adhesion complexes at the cell rear to allow detachment and productive motility. This process is mediated by a multitude of crosstalking signaling pathways downstream of integrin and growth factor activation. Using a poly(methyl methacrylate)-grafted-poly(ethylene oxide) (PMMA-g-PEO) copolymer base, we modify the PEO sidechains with immobilized epidermal growth factor (tEGF) as a model system for biomimetic scaffolds. We systematically adsorb fibronectin, vitronectin, and collagen ECM proteins to alter surface adhesiveness and measure MSC migration responses of speed and directional persistence alongside intracellular activities of EGFR, ERK, Akt, and FAK phosphoproteins. While tEGF and ECM proteins differentially affected signaling and migration, univariate correlations between signals and responses were not informative, prompting the need for multivariate modeling to identify key patterns. Using decision tree "signal-response" modeling, we predicted that inhibiting ERK on collagen-adsorbed tEGF polymer surfaces would increase cell mean free path (MFP) by increasing directional persistence. We confirmed this experimentally, successfully demonstrating a two-layer approach-"coarse" biomaterials followed by small molecules "fine-tuning"-to precisely and differentially control MSC migration speed and persistence, setting the stage for combination therapies for bone tissue engineering.
by Shan Wu.
Ph.D.