Dissertations / Theses on the topic 'Thrombopoietin'
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1
McIntosh, Bryan James. "Regulation of thrombopoietin in bone marrow." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3284334.
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Thesis (Ph. D.)--University of California, San Diego, 2007.Title from first page of PDF file (viewed January 9, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 50-58).
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Sangkhae, Veena. "The role of thrombopoietin signalling in JAK2V617F-positive myeloproliferative neoplasms." Thesis, University of York, 2015. http://etheses.whiterose.ac.uk/9669/.
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Thrombopoietin (TPO) is the primary regulator of megakaryocyte development, regulating proliferation and differentiation in addition to the number of circulating platelets through binding to and stimulation of the cell surface receptor MPL. Activating mutations in MPL constitutively stimulate downstream signalling pathways, leading to aberrant haematopoiesis and contribute to development of myeloproliferative neoplasms (MPNs). Several studies have mapped the tyrosine residues within the cytoplasmic domain of MPL that mediate these cellular signals; however, secondary signalling pathways are incompletely understood. Additionally, the identification of the JAK2V617F mutation has profoundly increased our understanding of MPNs and although a role has been implicated in vitro, the in vivo role of MPL in JAK2V617F-positive MPNs has yet to be determined. In this thesis, a novel signalling pathway for the negative regulation of TPO signalling was identified whereby MPLY591 is phosphorylated resulting in association of SYK which negatively regulates TPO-mediated ERK1/2 signalling. Additionally, genetic manipulation of an in vivo JAK2V617F-positive MPN mouse model led to the identification of MPL as an essential molecular component for development of JAK2V617F-postive MPNs. In the absence or reduction of MPL, the disease fails to develop. However, removal of the cytokine, TPO, was unable to prevent the disease from developing. These findings provide novel insights not only into regulation of TPO-signalling but also the role of TPO and MPL in JAK2V617F-positive MPN disease pathogenesis. Identification of the role of MPL in MPN pathogenesis, as well as insights into additional regulatory pathways, contributes to our understanding of normal and pathological TPO signalling. These new insights also provide a basis for development of novel therapeutics for the treatment of MPNs and other diseases resulting from aberrant of TPO signalling.
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Schulze, Harald. "Biochemische Untersuchungen zur Signaltransduktion des Thrombopoietin-Rezeptors c-Mpl in Thrombozyten." [S.l.] : [s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=957851413.
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Fleschutz, Frederik. "Bestimmung der Serumspiegel von Thrombopoietin und Erythropoietin bei Erst-, Vollblut- und Thrombozytapharesespendern /." Düsseldorf, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000253967.
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Barbieri, Daniela. "Role of thrombopoietin in DNA repair an genomic integrity in hematopoietic stem cells." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB002.
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Le maintien de l'intégrité génomique est crucial pour la préservation du potentiel des cellules souches hématopoïétiques (CSH). Les lésions de l'ADN dans les CSH sont associées à une capacité réduite à reconstituer l'hématopoïèse, à altérer le potentiel de différentiation et à accroître le risque de développer des tumeurs myéloïdes. Les éléments rétrotransposables (ER), se propageant dans le génome à travers un ARN intermédiaire, ont été associés à la perte d'auto-renouvellement, au vieillissement et aux dommages à l'ADN. Cependant, leur rôle dans les CSH n'avait pas été abordé. Dans cette étude, nous avons constaté que les CSH expriment des niveaux élevés d'ARNm de plusieurs ER comprenant des rétrovirus endogènes (ERV) et des L1 (LINE-1: Long Interspersed Nuclear Elements 1). Leur expression augmente avec l'irradiation. En utilisant des souris transgéniques L1-EGFP, on a montré que la rétrotransposition de L1 se produit dans les CSH in vivo. En outre, les inhibiteurs de la transcriptase inverse Efavirenz et ddC sauve à la fois les CSH des dommages persistants à l'ADN induit par l’irradiation et de la perte de prolifération in vitro. Ceci démontre que la rétrotransposition endogène joue un rôle important dans l'instabilité génomique de CSH induite par l’irradiation et dans leur perte de fonction. Nous avons précédemment montré que la thrombopoïétine (TPO), un facteur d'auto-renouvellement critique pour le CSH, limite les lésions de l'ADN induites par l’irradiation en améliorant la réparation de l'ADN. Nous avons découvert que le traitement par TPO empêche également l'expression et la mobilisation d’ER induite par l’irradiation. Nous avons aussi constaté que l’expression et la retrotransposition de L1 augmente dans les CSH provenant de souirs Mpl-/- et L1-EGFPxMpl-/-. Cela montre que la signalisation TPO in vivo est nécessaire pour restreindre l’expression et la retrotransposition d’ER dans les CSH au niveau basal et dans des conditions de stress. L'analyse transcriptomique a révélé que la TPO induit une réponse d'expression génique antivirale d'interféron (IFN) de type I dans les CSH. En utilisant des souris déficientes en STAT1/STAT2, nous démontrons que cette réponse est dépendante à la fois de STAT1 et de STAT2 et est requise pour l'inhibition de l'expression d’ER. En conclusion, cette étude montre que les ER représentent une importante source d’instabilité génomique dans les CSH. Les CSH sont capables de monter une réponse antivirale en réponse à la TPO comme un nouveau mécanisme pour limiter les dommages à l'ADN. Bien que la sécrétion constitutive d'IFN-I se produise chez des souris saines, les IFN sont produits abondamment principalement pendant les infections. Ainsi, la réponse d'expression de gène d'IFN induite par la TPO peut représenter un signal constitutif important et CSH-dédié; permettant à ces cellules de résister aux lésions de l'ADN induites par ER, tout en préservant leur capacité d'auto-renouvellementMaintenance of genomic integrity is crucial for the preservation of hematopoietic stem cell (HSC) potential. DNA damage in HSCs is associated with reduced ability to reconstitute hematopoiesis, altered lineage potential and accrued risk of developing myeloid malignancies. Retrotransposable elements (RE), spreading in the genome through an RNA intermediate, have been associated with loss of self-renewal, aging and DNA damage. However, their role in HSCs has not been addressed. In this study, we found that HSCs express high mRNA levels of several REs, including evolutionary recent long interspersed element-1 (L1) and endogenous retroviruses (ERV). Their expression further increases upon total body irradiation (TBI). Using L1EGFP transgenic reporter mice, we show that productive L1 retransposition occurs in HSCs in vivo. Furthermore, the reverse transcriptase inhibitors Efavirenz and ddC rescue TBI-induced both persistent DNA damage and HSC loss of proliferation in vitro. This demonstrates that endogenous retrotransposition plays an important role in TBI-induced HSC genomic instability and their loss of function. We have previously shown that thrombopoietin (TPO), a critical HSC self-renewal factor limits TBI-induced HSC DNA damage by improving DNA repair. We found that TPO treatment also prevents TBI-induced RE expression and mobilization. In addition, L1 expression and retrotransposition are increased in Mpl-/- and L1-EGFPxMpl-/- HSCs, showing that TPO signaling in vivo is required to restrain RE in HSCs, under both steady state and stress conditions. Transcriptomic analysis revealed that TPO induces an anti-viral, interferon (IFN) type-I like, gene expression response in HSCs. Using STAT1/STAT2-deficient mice, we demonstrate that this response is dependent on both STAT1 and STAT2 and is required for TPO-mediated RE expression inhibition in HSCs. Overall, this study shows that REs represent an important HSC intrinsic source of genomic instability and uncovers the ability of HSCs to mount an anti-viral innate immune state in response to TPO as a novel mechanism to minimize DNA damage. Although constitutive IFN-I secretion occurs in healthy mice, IFNs are produced abundantly mainly during infections. Thus, TPO-induced IFN gene expression response may represent an important constitutive, and HSC-dedicated, signal allowing HSCs to resist RE-induced DNA damage while preserving their self-renewal ability
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Sundaramoorthi, Hemalatha. "Identification of Hox Genes Controlling Thrombopoiesis in Zebrafish." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822768/.
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Thrombocytes are functional equivalents of mammalian platelets and also possess megakaryocyte features. It has been shown earlier that hox genes play a role in megakaryocyte development. Our earlier microarray analysis showed five hox genes, hoxa10b, hoxb2a, hoxc5a, hoxc11b and hoxd3a, were upregulated in zebrafish thrombocytes. However, there is no comprehensive study of genome wide scan of all the hox genes playing a role in megakaryopoiesis. I first measured the expression levels of each of these hox genes in young and mature thrombocytes and observed that all the above hox genes except hoxc11b were expressed equally in both populations of thrombocytes. hoxc11b was expressed only in young thrombocytes and not in mature thrombocytes. The goals of my study were to comprehensively knockdown hox genes and identify the specific hox genes involved in the development of thrombocytes in zebrafish. However, the existing vivo-morpholino knockdown technology was not capable of performing such genome-wide knockdowns. Therefore, I developed a novel cost- effective knockdown method by designing an antisense oligonucleotides against the target mRNA and piggybacking with standard control morpholino to silence the gene of interest. Also, to perform knockdowns of the hox genes and test for the number of thrombocytes, the available techniques were both cumbersome or required breeding and production of fish where thrombocytes are GFP labeled. Therefore, I established a flow cytometry based method of counting the number of thrombocytes. I used mepacrine to fluorescently label the blood cells and used the white cell fraction. Standard antisense oligonucleotide designed to the central portion of each of the target hox mRNAs, was piggybacked by a control morpholino and intravenously injected into the adult zebrafish. The thrombocyte count was measured 48 hours post injection. In this study, I found that the knockdown of hoxc11b resulted in increased number of thrombocytes and knockdown of hoxa10b, hoxb2a, hoxc5a, and hoxd3a showed reduction in the thrombocyte counts. I then screened the other 47 hox genes in the zebrafish genome using flow sorting method and found that knockdown of hoxa9a and hoxb1a also resulted in decreased thrombocyte number. Further, I used the dye DiI, which labels only young thrombocytes at specific concentrations and observed that the knockdown of hoxa10b, hoxb2a, hoxc5a, hoxd3a, hoxa9a and hoxb1a, lead to a decrease in young thrombocytes; whereas hoxc11b knockdown lead to increase in number of young thrombocytes. Using bromodeoxyuridine, I also showed that there is increase in release of young thrombocytes into peripheral circulation in hoxc11b knockdown fish which suggests that hoxc11b significantly promotes cell proliferation rather effecting apoptosis. In conclusion, I found six hox genes that are positive regulators and one hox gene is a negative regulator for thrombocyte development.
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Cheung, Manyee. "Investigation of megakaryocytes from normal and myeloproliferative bone marrow biopsies." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343012.
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Bulla, Camilo [UNESP]. "Seqüenciamento e expressão da trombopoietina canina." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/103774.
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Kafka, Isabell Katharina Anna. "Bestimmung der Serumkonzentration von Thrombopoietin bei Patienten mit Chemotherapie-, perioperativ- und ideopathisch-bedingter Thrombozytopenie sowie In-vitro-Untersuchungen der Thrombopoietin-Clearance von Thrombozyten und MEG-01-Zellen zur Optimierung der Behandlung thrombozytopenischer Patienten /." Düsseldorf, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000254041.
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Barnes, Calvin Langston Toure. "C-mpl Expression in Osteoclast Progenitors: A Novel Role for Thrombopoietin in Regulating Osteoclast Development." Yale University, 2006. http://ymtdl.med.yale.edu/theses/available/etd-06262006-123750/.
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A new paradigm has evolved in which multiple regulatory interactions between the skeletal and hematopoietic systems have been identified. Previous studies have demonstrated that megakaryocytes (MK) play a dual role in skeletal homeostasis by stimulating osteoblast proliferation and simultaneously inhibiting osteoclast (OC) development. Here we identify a novel regulatory pathway in which the main MK growth factor, thrombopoietin (TPO), directly regulates osteoclastogenesis. To study the role of TPO in OC development, spleen or bone marrow (BM) cells (2x10[exponent]6 cells/ml) or BM macrophages (BMM, 1x10[exponent]5 cells/ml) from C57BL/6 mice , as a source of OC precursors, were cultured with M-CSF (30 ng/ml) and RANKL (50 ng/ml) to induce OC formation. TPO (0.1-1000 ng/ml) and/or primary MK (0-0.5%), derived from C57BL/6 fetal livers, were titrated into these cultures and OC were identified as tartrate resistant acid phosphatase positive (TRAP+) giant cells with >3 nuclei. There was a significant, up to 15-fold reduction in OC formed when MK were added to all OC generating cultures, p < 0.001. Moreover, if OC generating cultures did not contain MK or MK progenitors, TPO treatment significantly enhanced OC formation up to six-fold, p < 0.01. This data demonstrates that MK are responsible for the inhibition of OC formation and that in cultures containing MK or MK progenitors such as BM or spleen cells, that TPO acts indirectly to inhibit OC formation by stimulating megakaryopoiesis, whereas in the absence of MK or MK progenitors TPO directly enhances OC formation. This conclusion is further supported by Real-Time PCR data which demonstrates that OC progenitors express c-mpl, the TPO receptor, albeit at low levels when compared to expression of c-mpl on MK. Finally, we have begun to dissect the c-mpl signaling pathway in OC progenitors. We have found that TPO induces tyrosine phosphorylation of several specific cellular proteins in the JAK/STAT pathway. Thus, TPO acts in a somewhat paradoxical manner by inhibiting OC formation through the stimulation of MK, while simultaneously playing a direct role in enhancing osteoclastogenesis.
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Fiedler, Janine [Verfasser]. "Biochemische und genetische Charakterisierung der Thrombopoietin-induzierten Signaltransduktion beim Thrombocytopenia-absent-radii-Syndrom / Janine Fiedler." Berlin : Freie Universität Berlin, 2012. http://d-nb.info/102985162X/34.
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Bulla, Camilo. "Seqüenciamento e expressão da trombopoietina canina /." Botucatu : [s.n.], 2005. http://hdl.handle.net/11449/103774.
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Larsson, Johanna. "Trombocyter – produktion och aktivering vid nephropathia epidemica : Hur och om mängden trombocyter, P-Selectin och thrombopoietin förändras under sjukdomsförloppet." Thesis, Umeå universitet, Biomedicinsk laboratorievetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-58630.
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Gurria, Juan P. "Thrombocytosis Following Pancreatectomy with Islet Autotransplantation in Children: Cincinnati Children's Hospital Experience." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1521191336859138.
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Rung, Olga [Verfasser]. "Untersuchungen zur Rolle von Lymphozyten, myeloiden Zellen und des Zytokins Thrombopoietin in der bakteriellen Meningitis / Olga Rung." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2018. http://d-nb.info/1154434176/34.
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Rose, Stefanie. "Der Effekt von Interferon alpha auf Thrombozyten und Thrombopoietin in Abhängigkeit vom Fibrosegrad bei Patienten mit chronischer Hepatitis C." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974923974.
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Rauber, Philip Jonas [Verfasser], and Beate [Akademischer Betreuer] Appenrodt. "Über die Bedeutung von Immature Platelet Fraction und Thrombopoietin bei Patienten mit Leberzirrhose / Philip Jonas Rauber ; Betreuer: Beate Appenrodt." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2019. http://d-nb.info/1197054561/34.
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Johnson, Lacey Nicole St George Clinical School UNSW. "Molecular regulation of Megakaryopoiesis: the role of Fli-1 and IFI16." Awarded by:University of New South Wales. St George Clinical School, 2006. http://handle.unsw.edu.au/1959.4/26819.
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Megakaryocytes (Mks) are unique bone marrow cells, which produce platelets. Dysregulated Mk development can lead to abnormal platelet number and the production of functionally defective platelets, causing bleeding, thrombotic events, and leukaemia. Understanding the molecular mechanisms driving megakaryopoiesis may yield insights into the molecular genetics and cellular pathophysiology of a diversity of disorders. The primary aim of this thesis was to gain insight into the molecular events required for normal Mk development. As transcription factors and cytokines play a central role in driving Mk development, both of these processes were investigated. Fli-1 and GATA-1 are key transcription factors regulating Mk-gene expression, alone and co-operatively. To understand the mechanism of transcriptional synergy exerted by Fli-1 and GATA-1, in vitro assays were carried out investigating the interactions between Fli-1, GATA-1 and DNA that mediate synergy. A novel mechanism of synergy was identified, where Fli-1 DNA binding is not required, although an interaction between Fli-1 and GATA-1, and GATA-1 DNA binding is required. Importantly, the results demonstrate that Fli-1 DNA binding is not essential for promoting Mk-gene expression in primary murine bone marrow cells. Thrombopoietin (TPO) is the primary cytokine responsible for Mk and platelet development. Identifying novel TPO gene-targets may provide invaluable information to aid the understanding of the complex and unique processes required for Mk development. Using microarray technology, IFI16 was identified as a TPO-responsive gene that has not previously been studied in the Mk lineage. This work demonstrated that IFI16 is expressed in CD34+ HSC-derived Mks, and that the Jak/STAT pathway is essential for the activation of IFI16 by both TPO and IFN-??. Of biological significance, IFI16 was found to regulate both the proliferation and differentiation of primary Mks, suggesting that IFI16 may control the balance between these two essential processes. In conclusion, the data in this thesis presents a novel mechanism through which Fli-1 and GATA-1 regulate the synergistic activation of Mk genes. The identification and functional characterisation of a novel TPO-inducible gene, IFI16, involved in regulating the proliferation and differentiation of Mks is also described. These findings have implications for several congenital and malignant conditions affecting Mk and platelet development, and possibly a mechanism for IFN-induced thrombocytopaenia.
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Corazza, Francis. "Contribution à l'étude de la physiopathologie de l'anémie et de la thrombocytopénie associées à une affection néoplasique chez l'enfant." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210291.
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L’objectif de notre travail était de déterminer le rôle joué par l’érythropoïétine et lathrombopoïétine, respectivement, dans l’anémie et la thrombocytopénie observées
chez des enfants souffrant d’une hémopathie maligne.
Par le dosage simultané de la forme soluble du récepteur de la transferrine et de
l’érythropoïétine dans le sérum nous avons montré que l’anémie observée chez ces
patients est bien la conséquence d’une réduction du nombre de progéniteurs
érythropoïétiques (atteinte médullaire centrale) mais que celle-ci n’est pas la
conséquence d’une production insuffisante d’érythropoïétine. Nous avons fait la
même observation chez des enfants souffrant d’une tumeur solide non
hématologique et chez des patients en cours de traitement par chimiothérapie.
Chez ces derniers patients, en appliquant un modèle de culture de moelle à long
terme, nous avons pu démontrer l’existence d’une altération du microenvironnement
médullaire, probablement induite par la chimiothérapie, se
traduisant par une réduction de son aptitude à supporter le développement de la
lignée érythroïde. Ceci expliquant au moins partiellement l’inadéquation de la
réponse érythropoïétique observée chez ces patients en réponse à l’anémie.
Dans la dernière partie du travail, nous avons montré que la thrombocytopénie très
fréquemment observée chez les patients leucémiques s’accompagne dans la
majorité des cas d’une élévation exponentielle de la concentration de
thrombopoïétine, excepté dans les cas de leucémies de la lignée myéloïde. Chez ces
derniers la concentration de thrombopoïétine est proche des valeurs observées chez
des sujets normaux alors qu’elle devrait être 10 à 100 fois plus élevée compte tenu
du nombre de plaquettes extrêmement bas. Nous avons pu montrer que ces taux
très bas sont la conséquence de la liaison de la thrombopoïétine à un récepteur
spécifique et fonctionnel présent à la surface des cellules leucémiques myéloïdes
qui, en l’utilisant comme facteur de croissance, (stimulant leur prolifération et
retardant leur mort cellulaire) « consomment » la thrombopoïétine présente dans le
sérum.
Doctorat en Sciences médicales
info:eu-repo/semantics/nonPublished
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Rojnuckarin, Ponlapat. "Mitogen-activated protein kinase pathways in megakaryocyte development /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/9200.
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Schmoldt, Hans-Ulrich. "Neue Enzyminhibitoren und Rezeptoragonisten durch Variation funktionaler Schleifen von Mikroproteinen." Doctoral thesis, [S.l.] : [s.n.], 2005. http://webdoc.sub.gwdg.de/diss/2005/schmoldt.
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Pelinski, Yanís. "Chromatin Disorganization as a Regulator of Irradiation-Induced L1Md Expression and Hematopoietic Stem Cell Function Thrombopoietin Protects Hematopoietic Stem Cells from Retrotransposon-Mediated Damage by Promoting an Antiviral Response." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS122.
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L'exposition à l’irradiation, comme lors des radiothérapies, affecte l'intégrité et la fonction des cellules souches hématopoïétiques (CSH). L’IR est donc associée au développement de maladies myéloïdes liées à la thérapie, telles que les syndromes myélodysplasiques (SMD) et les leucémies myéloïdes aiguës secondaires. Par conséquent, l'étude des mécanismes moléculaires qui contribuent à la perte de fonction des CSH induite par le stress, pourrait aider à identifier les patients à risque et à trouver éventuellement de nouvelles stratégies pour prévenir ces maladies.Notre équipe a récemment découvert un nouveau mécanisme responsable de la perte de fonction des CSH murines suite à l’IR qui implique les L1Md, les sous-familles jeunes et actives des éléments LINE-1. Nous avons montré que l'expression des L1Md est augmentée suite à l'IR et que cela entraîne une accumulation de dommages à l'ADN et de défauts des CSH. Nous avons également montré que la thrombopoïétine (TPO), une cytokine de niche des CSH , prévient la perte de fonction des CSH induite par l'IR, l'accumulation de dommages à l'ADN et la dérépression des L1Md.L'analyse de microarray a montré que la TPO induit un enrichissement des gènes de signalisation de l'IFN-I dans les CSH, dont beaucoup sont des facteurs de restriction virale. Au début de ma thèse, j'ai participé à une étude qui a montré que la TPO contrôlait l'expression des L1Md par cette voie de signalisation.Les L1Md sont reconnues comme des contributeurs majeurs des réseaux de régulation des gènes. Leur expression est étroitement régulée par des mécanismes épigénétiques, tels que la marque répressive de l'histone H3K9me3.Les principaux objectifs de mon projet de thèse sont donc de :1. Comprendre les mécanismes par lesquels l’IR affecte l'épigénétique des CSH, et en particulier l'hétérochromatine.2. Déterminer si la TPO, via sa signalisation de type IFN, peut réguler la répression des L1Md par des mécanismes épigénétiques.3. Déterminer si, et comment, l'expression des L1md peut affecter l'expression génique des CSH.Des expériences de ChIP-qPCR sur des CSH un mois après IR, montrent que la dérépression des L1Md est liée à une perte de H3K9me3 au niveau de leurs promoteurs, qui est empêché par la TPO. Ces résultats ont été confirmés par des expériences de ChIPseq montrant qu'une grande majorité des loci L1Md présentaient une perte de H3K9me3 suite à l’IR par rapport à la condition non irradiée, et que cela était empêché par la TPO. Ce n'était pas le cas pour les sous-familles de rétroéléments plus anciens, comme le Lx5, ou pour les rétrovirus endogènes. Les données RNAseq ont montré que l'IR dérégule fortement le transcriptome des CSH. Une injection de TPO 1h avant l’IR empêche cela. Nous montrons également que les gènes réprimés lors de l’IR, et pas dans la condition IR+TPO, sont significativement plus susceptibles de contenir un L1Md dans leurs introns que par hasard (p<0,05). Ceci est spécifique aux L1Md et aux gènes qui sont réprimés par l’IR. Certains de ces gènes sont impliqués dans l'oncogenèse ou la fonction des CSH. L’IR induit une perte de la signature CSH. Il est intéressant de noter que 55% des gènes appartenant à la signature CSH et qui sont réprimés lors de l’IR contiennent un L1Md dans leurs introns. L'orthologue humain de 75% des gènes réprimés lors de l’IR et hébergeant une L1Md, contient également un L1 jeune chez l’homme, suggérant une fonctionne conservée dans la régulation de l'expression des gènes hématopoïétiques.Nous avons analysé plusieurs cibles et validé une diminution de l'expression en IR accompagné d'une perte de H3K9me3 au niveau de leur L1Md intronique respective.Ces résultats montrent un lien entre l'IR et l'épigénétique des CSH, et suggèrent un rôle pour les L1Md dans la régulation de l'expression des gènes hématopoïétiquesExposure to ionizing radiations (IR), like in radiotherapy, affects hematopoietic stem cell (HSC) integrity and function. As a consequence, IR is associated with the development of therapy-related myeloid malignancies such as myelodysplastic syndromes (MDS) and secondary acute myeloid leukemias. Therefore, studying the molecular mechanisms that contribute towards stress-induced HSC loss of function, could help identify patients at risk and eventually find new strategies to prevent these diseases.Our team has recently uncovered a new mechanism responsible for murine HSC loss of function upon IR that involves L1Md, the young and active subfamilies of Long Interspersed Elements LINE-1. We showed that L1Md expression is increased following IR and that this leads to an accumulation of DNA damage and HSC defects. We have also shown that thrombopoietin (TPO), a niche HSC cytokine involved in self-renewal, prevents IR-induced HSC loss of function, accumulation of DNA damage and L1Md derepression.Microarray analysis had shown that TPO induced an enrichment of IFN-I signaling genes in HSCs, many of which are viral restriction factors. At the beginning of my PhD I was involved in a study that showed that TPO controlled L1Md expression via this signaling pathway. These results were published in J Exp Med in 2018, in an article in which I am co-first author.L1Md are recognized as major contributors of gene regulatory networks. Their expression is tightly regulated by epigenetic mechanisms, such as the repressive histone mark H3K9me3.The main objectives of my PhD project are thus to:1. Understand the mechanisms by which IR affects HSC epigenetics, and in particular heterochromatin.2. Determine if TPO, via its IFN-like signaling, may regulate L1Md repression through epigenetic mechanisms.3. Determine if, and how, L1md expression may impact HSC gene expression.We perfomed ChIP-qPCR experiments on HSCs one month post IR, and found that L1Md derepression is linked to a decreased H3K9me3 enrichment at their promoters, which is prevented by TPO. These results where further confirmed by ChIPseq experiments that showed that a vast majority of L1Md loci showed a reduced H3K9me3 enrichment upon IR compared to the non-irradiated condition, and that this was prevented by TPO. This was not the case for older retroelement subfamilies, such as the Lx5, or for endogenous retroviruses (ERV). RNA-seq data showed that IR strongly deregulates the HSC transcriptome. These effects are prevented by TPO injection 1h prior to IR. We also show that genes repressed upon IR, and not in the IR+TPO condition, are significantly more prone to contain an L1Md in their introns than by chance (p<0.05). This is specific for the L1Md family and for genes that are downregulated upon IR. Some of these genes are involved in oncogenesis or HSC function. IR induces a loss of the HSC signature. Interestingly, 55% of the genes belonging to the HSC signature and that are repressed upon IR contain an L1Md in their introns. The human orthologous of 75% of the genes repressed upon IR and hosting an L1Md, also host young human and primate L1, suggesting a conserved functional role of young L1 in regulating hematopoietic gene expression.We have analyzed in more details several target genes, and validated a decreased expression upon IR that is accompanied by a loss of H3K9me3 at their respective intronic L1Md.These results show for the first time a link between IR and HSC epigenetics, and suggest a role for L1Md in regulating hematopoietic gene expression
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Padilha, Pedro Henrique. "Variantes do gene THPO em pacientes com anemia aplástica adquirida." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/17/17154/tde-25042018-150914/.
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Introdução: A anemia aplástica (AA) adquirida é uma doença grave, caracterizada por pancitopenia e medula óssea hipocelular sem que haja associação com aumento de reticulina ou infiltração anormal na medula. Embora o mecanismo fisiopatológico não esteja totalmente elucidado, atribui-se a uma resposta imunomediada dos linfócitos T no ambiente medular. A trombopoetina (codificada pelo gene THPO) é um hormônio glicoproteico produzido pelo fígado e responsável pelo estímulo de crescimento de megacariócitos, desenvolvimento plaquetário e de demais linhagens e, quando disfuncional, contribui para o desenvolvimento da AA adquirida. Objetivos: Investigar a presença de variantes genéticas no THPO em amostras de sangue periférico e medula óssea de pacientes com AA adquirida (grupo caso) e de indivíduos saudáveis (grupo controle) e verificar a presença de alterações no número de plaquetas durante o seguimento dos pacientes com AA adquirida. Métodos: O gene THPO foi sequenciado em amostras de DNA de medula óssea de 92 pacientes com AA adquirida e no DNA de sangue periférico de 92 controles, cujas amostras haviam sido previamente armazenado no Laboratório de Hematologia da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP). O sequenciamento foi realizado pelo método de Sanger. Realizou-se também a associação entre a presença (ou ausência) de variantes em THPO e o número de plaquetas em 83 pacientes utilizando o teste ANOVA Para outras análises estatísticas, foram utilizados os testes t e qui-quadrado com nível de significância de 5%. Resultados: Foram encontrados três polimorfismos de nucleotídeo único (SNPs) nos pacientes com AA adquirida (rs956732, rs6141 e rs3804618). Os mesmos três SNPs foram observados nos indivíduos do grupo controle (p>0,05). Não houve associação entre o número de plaquetas e a presença de SNPs nos pacientes (p>0,05). Conclusões: Três SNPs foram encontrados em frequências alélicas semelhantes tanto no grupo de pacientes quanto nos controles, sugerindo que a trombopoetina não apresenta alterações genéticas que possam ser associadas à fisiopatologia da AA adquirida nessa coorte.Introduction: Acquired aplastic anemia (AA) is a severe illness, characterized by pancytopenia and hypocellular bone marrow without increased reticulin or abnormal infiltration of the bone marrow. Although the physiopathological mechanism has not been completely understood, an immune-mediated T-lymphocyte response has been attributed to the bone marrow environment. Thrombopoietin (encoded by THPO), a glycoprotein hormone produced by the liver and responsible for stimulating the growth of megakaryocytes, development of platelets and other lineages that when dysfunctional, contributes to the progress of acquired AA. Objectives: To screen the THPO gene for genetic variants in bone marrow of acquired AA patients and in the peripheral blood of controls, and to verify the correlation between the THPO status and platelet counts in the patients during the treatment. Method: Sanger sequencing of the THPO gene was carried out in 92 acquired AA patients (case group) and 92 controls, in DNA samples previously stored in the Hematology Laboratory of the Ribeirão Preto School of Medicine at the University of São Paulo. The association between the THPO status and the platelet counts was performed in 83 patients through the ANOVA test. The Chi-squared test and t-test were also applied for statistical analysis with a 5% significance level. Results: Three single nucleotide polymorphisms (SNPs) were found in the AA patients (rs956732, rs6141, and rs3804618), as well as in the healthy subjects (p>0,05). No association was verified between the platelet counts and the presence of SNPs in the AA patients (p>0,05). Conclusion: Three SNPs were found in both groups, suggesting that thrombopoietin does not harbor genetic variants that could be etiological for the acquired AA in our cohort.
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Lacoste, de Laval Bérengère de. "Rôle de la signalisation TPO dans la réparation de l’ADN des cellules souches hématopoïétiques." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05S027/document.
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A l’origine de l’hématopoïèse se trouve les cellules souches hématopoïétiques (CSH). Elles constituent un pool de cellules rares présentes dans la moelle osseuse aux niveaux de zones particulières de l’os appelées niche. Les cellules de la niche produisent des cytokines, telles que la thrombopoïétine (TPO), qui régulent les CSH en contrôlant leur quiescence et leur auto-renouvellement. Peu de choses sont connues sur les mécanismes mis en place par la CSH et son environnement pour faire face aux dommages de l’ADN, notamment induits lors de radio- ou chimio-thérapies. Durant cette étude, nous avons mis en évidence un nouveau rôle de la TPO et de son récepteur Mpl dans la réparation de l’ADN des CSH en réponse à des stress génotoxiques. Les CSH déficientes ou haplo-insuffisantes pour Mpl, ou les CSH sauvages et cultivées en absence de TPO, présentent un défaut de réparation et une instabilité génomique. En réponse à l’irradiation, la TPO potentialise l’activation de la voie NF-kB qui permet l’induction du gène précoce Iex-1. La TPO est également l’activateur majeur de la voie ERK dans les CSH. IEX-1 et pERK forment un complexe tripartite avec DNA-PK, une protéine clé de la voie Non Homologous End Joining (NHEJ). La DNA-PK est fortement activée par la TPO, ce qui augmente la fidélité et l’efficacité de la voie NHEJ et permet d’améliorer l’intégrité génomique des CSH. Par ailleurs, nous montrons qu’une simple injection de TPO ou de son agoniste Romiplostim, avant irradiation ou injection de doxorubicine, limite la mutagénèse des CSH et leur perte de fonction associée. Cet effet est spécifique de la TPO, d’autres cytokines comme le SCF et le Flt3-L, n’ont aucun effet sur la réparation. Ces résultats montrent que la TPO contrôle directement les voies de signalisation aboutissant à la réparation de l’ADN des CSH. Ils ouvrent des perspectives nouvelles pour l’utilisation des agonistes de la TPO comme adjuvant protecteur avant radio- ou chimiothérapie pour minimiser les risques de développement de leucémies aigües myéloïdes secondaires. L’expression de Mpl étant haploinsuffisante pour la fonction de réparation de l’ADN, ces résultats suggèrent que Mpl pourrait être tumeur suppresseur en réponse aux traitements chimio-ou radio-thérapeutiquesHematopoietic stem cells (HSC) are at the beginning of hematopoeisis. They constitute a pool of rare cells in bone marrow in specifics zones of bones called niche. Niche’s cells produce cytokines, like thrombopoietin (TPO). These cytokines regulates HSC by controlling quiescence and self-renewal. Few are known about mechanism used by HSC and its environment to prevent DNA damage, and especially those induced by radio- or chemo-therapies. In this study, we discover a new role of TPO and its receptor Mpl in DNA repair of HSC in response to genotoxic stress. HSC without Mpl, or wild type HSC cultured without TPO, show an important defect of DNA repair and genomic instability. In response to irradiation, TPO increases activation of NF-KB pathway that increases induction of IEX-1 early gene. TPO is also the major activator of ERK pathway in HSC. IEX-1 and p-ERK can form a tripartite complex with DNA-PK, a key protein of Non homologous end joining pathway (NHEJ). DNA-PK is fully activated by TPO which increase fidelity and efficacy of NHEJ pathway leading to better genomic integrity of HSC. We also show in this study that a simple injection of TPO or Romiplostim before irradiation or Doxorubicin injection, decrease mutagenesis of HSC and their loss of function associated. This effect of TPO is specific of TPO because other cytokines like SCF or Flt3-L have no effect on the DNA repair. These results show that TPO can directly control signaling pathway leading to repair of HSC’s DNA and open new avenues for TPO agonist using. They can be used to protect HSC before radio- or chemo-therapies and to minimize development of secondary acute myeloid leukemia. Expression of Mpl being haplo-insufficient for DNA repair functions, this result suggests that Mpl could be a tumor suppressor in response to radio- or chemo-therapies treatments
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Besbes, Samaher. "Rôle de la Protéine C, un anticoagulant naturel, dans l’association thrombose et cancer." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA11T048/document.
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Il est désormais admis que le caractère invasif d'une tumeur est lié, non seulement, au génotype des cellules cancéreuses, mais aussi à leurs interactions avec le microenvironnement tumoral (MT). Au sein du MT, une déstabilisation de la matrice stromale favorise la progression tumorale et la dissémination métastatique. Le remaniement de la matrice extracellulaire est souvent piloté par des enzymes protéolytiques. En revanche, les effets de l'inhibition de la formation de cette matrice sont peu étudiés. C’est dans cette optique que nous nous sommes intéressés à la protéine C (PC) et son récepteur endothélial (EPCR) et à leur rôle dans la tumorigenèse des leucémies et des cancers solides.L’EPCR est exprimé par un grand nombre de lignées cellulaires cancéreuses. Il est aussi détecté dans le compartiment tumoral chez des patients atteints de pathologie tumorale. Son gène est hautement conservé. Il possède cependant plusieurs polymorphismes. Un de ces SNPs (single nucleotide polymorphism) - 6936A/G - se traduit par la libération d'une forme soluble circulante de l'EPCR (EPCRs) résultant de la protéolyse de la forme membranaire. Chez des patients leucémiques, une fréquence élevée du SNP 6936A/G est observée et associée à la survenue de thrombose. D'autre part, l’EPCR est détecté in situ dans la majorité des biopsies tumorales testées et sécrété en grande quantité dans les ascites. La fixation de la PC sur l’EPCR et son activation augmentent la survie et le potentiel migratoire des cellules cancéreuses. Aussi, la PCA est capable de moduler, par communication paracrine, la sécrétion de plusieurs interleukines et cytokines. Ainsi, la stimulation de cellules du cancer de l'ovaire par la PCA induit la synthèse d'une thrombopoéïtine ovarienne fonctionnelle. Cette cytokine étant régulatrice de la production de plaquettes, la PCA semble être de nouveau à l'interface entre troubles de l'hémostase et pathologie cancéreuse. L’élucidation du rôle complexe de la PCA et de son récepteur endothélial dans la carcinogenèse permettrait non seulement de dégager de nouvelles approches thérapeutiques, mais aussi de prévenir le risque de thrombose associée au cancer et d’en réduire la morbiditéIt is now recognized that the invasiveness of tumor cells is not only related to the genotype of these cells but also to their interaction with tumor microenvironment (TM). Within the TM, stromal matrix destabilization promotes tumor progression and metastatic dissemination. The extracellular matrix remodeling is often driven by proteolytic enzymes. However, few studies have investigated the effects of an impairment of the matrix formation. Given these facts and circumstances, we were interested in protein C (PC) and its endothelial receptor (EPCR), as well as in their role in tumorigenesis in leukemia and solid cancers. EPCR is expressed by a wide range of cancer cell lines. It is also detected within the tumor compartment in patients with malignant diseases. EPCR gene is highly conserved but nevertheless contains polymorphisms. One of these SNPs (single nucleotide polymorphism) - 6936A/G – reflects – in the release of a soluble circulating form (EPCRs) resulting from the proteolysis of membrane-associated form. In leukemic patients a high incidence of 6936A/G SNP is observed and associated with thrombosis events. Moreover, EPCR is detected in the majority of tumor biopsies and is abundantly secreted in ascitic fluid. The PC attachment to EPCR and its activation promotes cell survival and migratory potential of tumor cells. Also, APC is able to modulate, by a paracrine manner, interleukins and cytokines secretion. Thus, ovarian cancer cells stimulation by APC induces the synthesis of a functional ovarian thrombopoietin. As this cytokine has a regulatory effect on platelet production, APC may be once again at the interface between hemostasis disorders and coagulation. The elucidation of the intricate role of APC and its endothelial receptor could permit not only to identify new therapeutic approaches but also to prevent cancer-associated thrombosis risk and to decrease morbidity in cancer patients
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Hirata, Shinji. "Congenital amegakaryocytic thrombocytopenia iPS cells exhibit defective MPL-mediated signaling." Kyoto University, 2018. http://hdl.handle.net/2433/232073.
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Williams, Christopher M. "Protein kinase Ca in bone eevelopment, thrombopoiesis and thrombosis." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526061.
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Hall, Mark Andrew. "Characterisation of the interleukin 11 receptor complex." Thesis, University of Birmingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396241.
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Fock, Ee-Ling Clinical School St George Hospital Faculty of Medicine UNSW. "Molecular regulation and enhancement of megakaryopoiesis and thrombopoiesis by the p45 subunit of NF-E2." Publisher:University of New South Wales. Clinical School - St George Hospital, 2008. http://handle.unsw.edu.au/1959.4/42885.
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Megakaryocytes (MKs) are a rare population of haematopoietic cells, which produce platelets. Platelet production is a complex process that is tightly regulated at the transcriptional level by lineage specific transcription factors such as p45 NF-E2. Understanding how transcriptional regulators operate is imperative to advance our knowledge of disease pathophysiology and to propose novel treatment options. Therefore, the aims of this study were to: i) study the effects of p45 NF-E2 overexpression on various stages of megakaryopoiesis; (ii) elucidate the nuclear transport mechanisms of p45 NF-E2; and iii) determine the impact of a p45 NF-E2 modification called SUMOylation on thrombopoiesis. Exogenous p45 NF-E2 was overexpressed in haematopoietic cells in culture and various aspects of megakaryopoiesis were examined. Overexpression of p45 NF-E2 enhanced multiple stages of MK differentiation such as colony forming unit (CFU)-MK formation and terminal MK maturation. Most importantly, p45 NF-E2 overexpression resulted in significant increases in proplatelet and functional platelet production in vitro. This latter result was confirmed in vivo using lethally irradiated mice transplanted with cells that overexpressed p45 NF-E2. Unexpectedly, the enhancement of MK differentiation was at the expense of myeloid development and, for the first time, identified p45 NF-E2 as a negative regulator of myeloid differentiation. Secondly, we determined the nuclear localisation signal of p45-NF-E2 and the pathway responsible for nuclear import. We also investigated the importance of p45 NF-E2 nuclear import in thrombopoiesis. Finally, we showed that p45 NF-E2 is modified mainly by SUMO-2/3 in bone marrow cells and this process is involved in the transcriptional activation of MK-specific genes and platelet release. Taken together, these results suggest that enforced expression of p45 NF-E2 selectively enhances many aspects of MK differentiation including early and terminal MK maturation, proplatelet formation and platelet release. Equally important, this thesis also indicates that white blood cell differentiation may be inhibited by p45 overexpression, while molecular processes such as the nuclear import and SUMOylation of p45 NF-E2 are vital for thrombopoiesis. These observations will facilitate subsequent studies into the feasibility of manipulating p45 NF-E2 protein levels for the treatment of conditions such as thrombocytopaenia and other platelet disorders.
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Svensson, Tobias. "Infectious and bleeding complications in patients with hematological malignancies : Studies on diagnosis and prevention." Doctoral thesis, Uppsala universitet, Hematologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-316461.
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The overall aim of this thesis is to improve knowledge about the prevention of infectious and bleeding complications in patients with hematological malignancies, primarily in those with chronic lymphocytic leukemia (CLL) and myelodysplatic syndrome (MDS). Hypogammaglobulinemia, impaired production of immunoglobulins (Ig), is an established risk factor for infection, but the impact of IgG pure subclass deficiency (IgG subclass deficiency with adequate production of IgG, IgA, and IgM) has been debated. In a retrospective single institution study, we concluded that pure IgG subclass deficiency in CLL patients is rare and is not associated with an increased risk of infection. Hence, routine analysis of IgG subclasses in patients with CLL is not warranted. There is no consensus on recommending vaccination against Streptococcus pneumoniae to CLL patients mainly because comparative studies are lacking. In our randomized trial, the efficacy of a conjugated pneumococcal vaccine on immune response was superior or equal to a polysaccharide vaccine for all pneumococcal serotypes common for the two vaccines. A conjugate pneumococcal vaccine should therefore be included in vaccination programs for patients with CLL. Bronchoalveolar lavage (BAL) is a well-established invasive method to identify the cause of pulmonary infiltrates in immunocompromised patients. In a retrospective trial, we have studied the diagnostic yield of BAL in patients with hematological malignancies. We concluded that BAL is highly useful in either verifying or excluding some of the important respiratory tract infections affecting these patients, particularly invasive pulmonary aspergillosis (IPA) and Pneumocystis jirovecii pneumonia (PJP). However, standardized procedures for BAL sampling should be continually revised to avoid unnecessary microbiological tests. Thrombocytopenia, an adverse prognostic factor in patients with MDS, can be aggravated by azacitidine, first-line treatment for high-risk MDS. Eltrombopag, a thrombopoietin-receptor agonist (TPO-R), alleviates thrombocytopenia in patients with immune thrombocytopenic purpura (ITP). In a phase I clinical trial, we concluded that the combination of eltrombopag and azacitidine in high-risk MDS patients with thrombocytopenia is feasible and well tolerated in doses up to 200 mg eltrombopag daily.
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Zhang, Zhe [Verfasser], and Steffen [Akademischer Betreuer] Massberg. "The role of leukocyte-megakaryocyte interactions during the thrombopoiesis / Zhe Zhang ; Betreuer: Steffen Massberg." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1238016936/34.
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Pallard, Caroline. "Etude comparative du mecanisme d'ation des cytokines : analyse des facteurs transcriptionnels stats (doctorat : hematologie cancerologie)." Paris 11, 1996. http://www.theses.fr/1996PA11T039.
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Madera, Dmitri. "Cooperating Events in Core Binding Factor Leukemia Development: A Dissertation." eScholarship@UMMS, 2011. https://escholarship.umassmed.edu/gsbs_diss/532.
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Leukemia is a hematopoietic cancer that is characterized by the abnormal differentiation and proliferation of hematopoietic cells. It is ranked 7th by death rate among cancer types in USA, even though it is not one of the top 10 cancers by incidence (USCS, 2010). This indicates an urgent need for more effective treatment strategies. In order to design the new ways of prevention and treatment of leukemia, it is important to understand the molecular mechanisms involved in development of the disease.
In this study, we investigated mechanisms involved in the development of acute myeloid leukemia (AML) that is associated with CBF fusion genes. The RUNX1 and CBFB genes that encode subunits of a transcriptional regulator complex CBF, are mutated in a subset (20 – 25%) of AML cases. As a result of these mutations, fusion genes called CBFB-MYH11 and RUNX1-ETO arise. The chimeric proteins encoded by the fusion genes provide block in proliferation for myeloid progenitors, but are not sufficient for AML development. Genetic studies have indicated that activation of cytokine receptor signaling is a major oncogenic pathway that cooperates in leukemia development. The main goal of my work was to determine a role of two factors that regulate cytokine signaling activity, the microRNA cluster miR-17-92 and the thrombopoietin receptor MPL, in their potential cooperation with the CBF fusions in AML development.
We determined that the miR-17-92 miRNA cluster cooperates with Cbfb-MYH11 in AML development in a mouse model of human CBFB-MYH11 AML. We found that the miR-17-92 cluster downregulates Pten and activates the PI3K/Akt pathway in the leukemic blasts. We also demonstrated that miR-17-92 provides an anti-apoptotic effect in the leukemic cells, but does not seem to affect proliferation. The anti-apoptotic effect was mainly due to activity of miR-17 and miR-20a, but not miR-19a and miR-19b.
Our second study demonstrated that wild type Mpl cooperated with RUNX1-ETO fusion in development of AML in mice. Mpl induced PI3K/Akt, Ras/Raf/Erk and Jak2/Stat5 signaling pathways in the AML cells. We showed that PIK3/Akt pathway plays a role in AML development both in vitro and in vivo by increasing survival of leukemic cells. The levels of MPL transcript in the AML samples correlated with their response to thrombopoietin (THPO). Moreover, we demonstrated that MPL provides pro-proliferative effect for the leukemic cells, and that the effect can be abrogated with inhibitors of PI3K/AKT and MEK/ERK pathways.
Taken together, these data confirm important roles for the PI3K/AKT and RAS/RAF/MEK pathways in the pathogenesis of AML, identifies two novel genes that can serve as secondary mutations in CBF fusions-associated AML, and in general expands our knowledge of mechanisms of leukemogenesis.
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Abina, Mohammed Amine. "Transfert de gene a l'aide d'adenovirus recombinants : importance de la reponse immune contre le produit du transgene; interet en hemato-oncologie." Besançon, 1997. http://www.theses.fr/1997BESA3013.
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Zhang, Lin [Verfasser], Steffen [Akademischer Betreuer] Massberg, Stefan [Akademischer Betreuer] Engelhardt, and Dirk [Akademischer Betreuer] Busch. "The effect of Sphingosine 1-phosphate (S1P) on thrombopoiesis / Lin Zhang. Gutachter: Stefan Engelhardt ; Dirk Busch. Betreuer: Steffen Massberg." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1020915080/34.
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Eeuwijk, Judith Martina Maria van [Verfasser], and Bernhard [Gutachter] Nieswandt. "Studies on thrombopoiesis and spleen tyrosine kinase-mediated signaling in platelets / Judith Martina Maria van Eeuwijk ; Gutachter: Bernhard Nieswandt." Würzburg : Universität Würzburg, 2018. http://d-nb.info/1151128600/34.
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Choudry, Fizzah Aziz. "Novel insights into megakaryopoiesis, thrombopoiesis and acute coronary thrombosis : transcriptome profiling of the haematopoietic stem cell, megakaryocyte and platelet." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/283252.
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The aim of this project was to investigate the transcriptome of human haematopoietic stem cells (HSCs), megakaryocytes and platelets to gain insights into steady state and accelerated thrombopoiesis that occurs in states of haemostatic demand and in thrombosis by applying these findings to the pathological setting of acute coronary thrombosis. To investigate transcriptional heterogeneity within the human HSC population, single cell RNA sequencing was performed in human bone marrow HSCs. Transcriptionally distinct subpopulations were identified including two megakaryocyte biased subsets with potentially differing functional relevance. Both populations expressed megakaryocyte specific transcripts, one of which also co-expressed common myeloid and megakaryocyte-erythroid progenitor transcripts while the other did not. This study represents the first interrogation of the human bone marrow megakaryocyte transcriptome. Cells were collected from healthy human bone marrow and analysed by low input and single cell RNA sequencing. To identify novel drivers of megakaryocyte maturation, the human bone marrow megakaryocyte transcriptome was compared to that of megakaryocytes cultured from human CD34+ cells, a process known to generate immature megakaryocytes. Transcriptional signatures associated with increasing megakaryocyte ploidy were then investigated. Increasing megakaryocyte ploidy level was found to be associated with an upregulation of transcripts involved in translation and protein processing as well as expression of a number of transmembrane receptors which might have functional relevance. Finally, the pathological setting of acute coronary thrombosis was used as a model for accelerated thrombopoiesis. Megakaryocyte and platelet transcriptomes were compared between patients with acute myocardial infarction (AMI) as well as severe coronary disease and a control group. The transcriptional signature relating to disease compared to control in megakaryocytes included upregulation of platelet activation related transcripts in megakaryocytes isolated from patients with AMI and severe coronary artery disease.
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Filippi, Marie-Dominique. "Les cellules souches embryonnaires de souris : modèle d'étude de Mpl, le récepteur de la thrombopoi͏̈étine." Paris 5, 2001. http://www.theses.fr/2001PA05P028.
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FILIPPI, MARIE-DOMINIQUE. "Etude de la fonction de domaines intracytoplasmiques de mpl dans les cellules hematopoietiques derivees in vitro des cellules es en reponse a la thrombopoietine." Paris 7, 2000. http://www.theses.fr/2000PA077081.
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Nous avons choisi la differenciation hematopoietique in vitro des cellules souches embryonnaires (cellules es) de souris inactivees pour le gene c-mpl (mpl - / -) pour etudier la fonction de differents domaines intracellulaires de mpl, le recepteur de la thrombopoietine (tpo), dans differents compartiments hematopoietiques en reponse a la tpo seule ou en synergie avec d'autres cytokines. Ce modele donne acces, en plus des progeniteurs myeloides et des cellules matures, a des cellules plus immatures, les bl-cfc (blast colony-forming cell) qui representent l'equivalent in vitro de l'hemangioblaste. Dans nos conditions, mpl ou les differents mutants sont exprimes dans toutes les cellules derivees des cellules es. Tout d'abord la reintroduction de mpl dans les cellules es mpl - / - permet (1) de restaurer la reponse des cfu-mk et des megacaryocytes (mks) a la tpo (2) le developpement, en reponse a la tpo seule, de tous les autres progeniteurs myeloides (bfu-e, cfu-gm et cfu-mix) et celui des bl-cfc, normalement dependantes du vegf, indiquant que mpl n'a pas de role instructif et peut se substituer aux autres recepteurs de cytokines mais aussi a un recepteur a activite tyrosine kinase intrinseque, flk-1 un des recepteurs du vegf, (3) un effet synergique de la tpo et d'autres cytokines sur le developpement des bl-cfc et des cfu-gm. Les regions consensus boite 1 et boite 2 qui fixent la proteine tyrosine kinase jak2 sont indispensables a la fonction de mpl. La deletion du domaine c-terminal de mpl n'annule pas completement le developpement des cfu-mk et de bfu-e en presence de tpo, un nombre faible mais significatif se developpe. Par contre, elle annule completement celui des cfu-gm et bl-cfc en presence de tpo. Cette deletion
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GONCALVES, FREDERIQUE. "Etude des mecanismes de la determination des cellules hematopoietiques pluripotentes : approche par transfert des sequences codant pour les recepteurs de l'erythropoietine et de la thrombopoietine." Paris 6, 1997. http://www.theses.fr/1997PA066087.
Full textAbstract:
Le sujet de ma these a ete l'etude des mecanismes moleculaires de la determination des cellules souches hematopoietiques pluripotentes. Pour etudier le role de molecules regulatrices (facteurs de croissance et leurs recepteurs, facteurs de transcription ou encore elements de la transmission des signaux de transduction) sur la determination des cellules souches, leurs sequences codantes ont ete introduites, par infection retrovirale, dans des cellules pluripotentes hematopoietiques murines et humaines. Les consequences possibles de cette manipulation genetique ont ete etudiees. Dans une premiere partie du travail, la reconstitution clonale de l'hematopoiese d'une souris irradiee a ete mise au point. En effet, seule une reconstitution clonale permettrait de comprendre les consequences de l'expression d'un transgene sur le devenir a long terme d'une cellule souche. Pour realiser cet abord, nous avons tire partie des proprietes des cfu-s de souris traitees au 5-fu a reconstituer l'hematopoiese de souris irradiees a dose letale. Cependant, il a ete montre dans le laboratoire que dans les protocoles d'infection retrovirale, les cfu-s venant de souris traitees au 5-fu perdent leur propriete de reconstituer l'hematopoiese de souris irradiees a dose letale. Nous avons teste differentes conditions d'infection retrovirale permettant le maintien des proprietes des cellules souches. En particulier, les lignees productrices de retrovirus recombinants classiques ont ete remplacees par des cellules stromales murines competentes pour le maintien de l'hematopoiese (ms-5). L'infection retrovirale des cellules hematopoietiques pluripotentes realisee en presence de cellules ms-5 et de surnageant retroviral permet d'infecter efficacement les cfu-s et de maintenir leur propriete de reconstituer l'hematopoiese de souris irradiees a dose letale. Malheureusement, lorsqu'une seule cfu-s est greffee, elle n'est capable de reconstituer l'hematopoiese qu'a court terme et l'hematopoiese a long te rme est assuree par des cellules souches endogenes ayant resiste a l'irradiation. Dans la seconde partie de mon travail de these, les sequences codantes du recepteur de l'erythropoietine (r-epo) et du recepteur de la thrombopoietine (c-mpl) ont ete transferees dans des cellules hematopoietiques pluripotentes murines et humaines et les consequences de l'expression constitutive de ces recepteurs ont ete etudiees sur leur determination, proliferation et/ou differenciation. Nous avons montre qu'in vitro les progeniteurs pluripotents murins exprimant constitutivement r-epo ou c-mpl : (1) proliferent en reponse a l'erythropoietine (epo) ou a la thrombopoietine (tpo) seule ; (2) ne s'engagent pas preferentiellement vers la differenciation erythroblastique ou megacaryocytaire et (3) peuvent se differencier en cellules erythroblastiques et megacaryocytaires matures mais ne peuvent se differencier en cellules granulo-macrophagiques matures a l'echelle unicellulaire. In vivo, l'hematopoiese de souris irradiees a dose letale greffees avec des cellules souches exprimant constitutivement c-mpl, a court terme et a long terme, est identique a celle de souris greffees avec des cellules souches exprimant constitutivement un gene temoin. Dans la derniere partie du travail, nous avons developpe des modeles cellulaires pour etudier les mecanismes moleculaires de la determination et de la differenciation de cellules pluripotentes. La sequence codante de c-mpl a ete transferee dans deux lignees continues humaines pluripotentes de phenotype erythroblastique et megacaryocytaire, tf-1 et ut-7. Les cellules tf-1 et ut-7 exprimant constitutivement c-mpl proliferent en reponse a la tpo. De plus, la tpo inhibe la differenciation erythroblastique induite par l'epo. Par ailleurs, la tpo induit la differenciation megacaryocytaire uniquement dans les cellules ut-7/c-mpl. Les mecanismes moleculaires de ce phenomene sont en cours d'exploration et les premiers resultats suggerent que l'inhibition de la differenciation erythroblastique induite par la tpo dans les cellules tf-1/c-mpl serait liee a une regulation negative de gata-1. Les effets de la tpo ressemblent a ceux des esters de phorbol (activateurs de la pkc) qui d'une part inhibent la differenciation erythroblastique et d'autre part induisent la differenciation megacaryocytaire. Nous avons montre que des inhibiteurs de la pkc ne modifient pas l'action de la tpo sur les cellules ut-7/c-mpl ce qui suggere que l'action de la tpo ne serait pas mediee par l'activation de la pkc.
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Meyer, Imke [Verfasser]. "The functional blood platelet and its biogenesis : Biochemical and cell biological analysis of thrombopoiesis in vitro, in situ and in vivo / Imke Meyer." Berlin : Freie Universität Berlin, 2013. http://d-nb.info/1031666958/34.
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Oates, Jennifer S. M. "Thrombopoietin mediated regulation of murine hematopoietic progenitors." Thesis, 2002. http://hdl.handle.net/2429/13446.
Full textAbstract:
A number of studies have suggested that primitive hematopoietic cells respond to thrombopoietin (TPO) and that this growth factor has a non-redundant role in regulating early stages of hematopoiesis. The present study was designed to investigate more precisely the effects of an absence of TPO-mediated signaling in vivo on the generation/maintenance of specific subsets of primitive hematopoietic cells and to evaluate their ability to generate derivative progenitors in response to various growth factors in vitro. Initial tests confirmed that colony-forming cell (CFC) frequencies in the marrow of both types of mutant mice were reduced (~2-fold) and showed that longterm culture-initiating cell (LTC-IC) numers were even further reduced (~3-fold). The marrow of tpo[sup -/-] and c-mpl[sup -/-] mice also contained fewer Sca-1⁺(S⁺) lineage marker-negative (lin⁻) Hoechst 33342-stained side population (SP) and S⁺ c-kit⁺ L⁻ (S⁺K⁺L⁻) cells (~2-fold). The CFC output per LTC-IC from tpo[sup -/-] and c-mpl[sup -/-] mice was also reduced (~3-fold) as shown by both limiting dilution assays and single cell LTC-IC cultures. Similarly, 10-day suspension cultures of S⁺K⁺L⁻ and S⁺L⁻ SP cells from tpo[sup -/-] and c-mpl[sup -/-] mice produced 3- 5-fold fewer CFCs, regardless of the growth factors added. Single cell cultures showed this was due to a decreased number of mutant clones containing CFCs. Addition of either TPO or interleukin-11 to Steel factor (SF) and flt3-ligand (FL) in cultures of tpo[sup -/-] S⁺K⁺L⁻ cells also failed to enhance the generation of LTC-IC activity in spite of an ability of IL-11 to elicit such a response. The most significant findings from these studies are: 1) in vivo TPO-mediated signaling is required for the generation of normal sized compartments of several stages of early hematopoietic progenitors with the most profound influence seen on the more primitive cells; and 2) in the presence of SF and FL in vitro, TPO does not enhance the output of primitive progenitors from +/+ cells beyond that obtained by the activation of gp130.
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"In vitro and in vivo effects of thrombopoietin on protection against hypoxia-ischemia-induced neural damage." 2008. http://library.cuhk.edu.hk/record=b5893561.
Full textAbstract:
Chiu, Wui Man.Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 107-128).
Abstracts in English and Chinese.
Abstract --- p.i
中文摘要 --- p.iv
Acknowledgements --- p.vi
Publications --- p.viii
Table of Contents --- p.ix
List of Tables --- p.xiv
List of Figures --- p.xv
List of Abbreviations --- p.xviii
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Hypoxic-ischemic encephalopathy in human infants --- p.1
Chapter 1.1.1 --- Incidence --- p.1
Chapter 1.1.2 --- Biphasic development of HI brain damage --- p.2
Chapter 1.1.2.1 --- Initiating mechanism: energy failure in immature brain --- p.3
Chapter 1.1.2.2 --- Biochemical cascades --- p.4
Chapter 1.1.2.2.1 --- Excitatory amino acid receptor activation by glutamate --- p.4
Chapter 1.1.2.2.2 --- Intracellular calcium accumulation --- p.4
Chapter 1.1.2.2.3 --- Formation of free radicals --- p.5
Chapter 1.1.2.2.3.1 --- Reactive oxygen species (ROS) --- p.5
Chapter 1.1.2.2.3.2 --- Nitric oxide (NO) --- p.6
Chapter 1.1.2.3 --- Release of inflammatory mediators --- p.6
Chapter 1.1.2.4 --- Mitochondrial dysfunction --- p.7
Chapter 1.1.2.5 --- Final path to death: necrosis or apoptosis --- p.8
Chapter 1.1.2.6 --- Ways to change: neuronal survival and proliferation signaling --- p.8
Chapter 1.1.3 --- Interventions for neonatal hypoxia-ischemia --- p.9
Chapter 1.2 --- Animal models mimicking hypoxia-ischemia brain injury --- p.12
Chapter 1.2.1 --- Comparisons of animal models of hypoxia-ischemia --- p.12
Chapter 1.2.2 --- Development of neonatal rat model with hypoxic-ischemic damage --- p.14
Chapter 1.3 --- Neural stem/progenitor cells --- p.15
Chapter 1.3.1 --- Effect of hypoxic-ischemia on neural stem/progenitor cells --- p.17
Chapter 1.4 --- Thrombopoietin --- p.18
Chapter Chapter 2 --- Objectives --- p.23
Chapter Chapter 3 --- Materials and Methodology --- p.24
Chapter 3.1 --- Establishment of neonatal rat model of HI brain damage and effects of TPO on neural protection --- p.24
Chapter 3.1.1 --- Animal protocols --- p.24
Chapter 3.1.2 --- Induction of HI brain damage in neonatal rats --- p.24
Chapter 3.1.3 --- Treatment with TPO --- p.25
Chapter 3.1.4 --- Sacrifice of rats --- p.25
Chapter 3.1.5 --- Read-out measurements --- p.26
Chapter 3.1.5.1 --- Brain weight --- p.26
Chapter 3.1.5.2 --- Gross injury assessment of the right hemisphere --- p.26
Chapter 3.1.5.3 --- Histology --- p.27
Chapter 3.1.5.4 --- Blood cell count --- p.27
Chapter 3.1.5.6 --- Functional assessments --- p.28
Chapter 3.1.5.6.1 --- Grip traction test --- p.28
Chapter 3.1.5.6.2 --- Elevated body swing test --- p.28
Chapter 3.1.5.7 --- Statistical analysis --- p.28
Chapter 3.2 --- Establishment of in vitro model of primary mouse NSPs and the effect of TPO on their proliferation --- p.29
Chapter 3.2.1 --- Mouse embryo dissection for the extraction of NSP --- p.29
Chapter 3.2.2 --- Culturing of NSP --- p.30
Chapter 3.2.3 --- Immunofluorescence staining for stem cell markers --- p.31
Chapter 3.2.4 --- Neurosphere assay with different combinations of mitogens --- p.31
Chapter 3.2.5 --- Neurosphere assay with different concentrations of TPO --- p.32
Chapter 3.2.6 --- Neurosphere assay under hypoxia --- p.32
Chapter 3.2.7 --- Statistical analysis --- p.33
Chapter Chapter 4 --- Effects of thrombopoietin on neonatal rat models of hypoxia-ischemia brain damage --- p.39
Chapter 4.1 --- Summary of experimental settings --- p.39
Chapter 4.2 --- Results --- p.39
Chapter 4.2.1 --- Mortality --- p.39
Chapter 4.2.2 --- Effects of TPO on p7 mild damage model 1 week post-surgery --- p.40
Chapter 4.2.2.1 --- Body and brain weights --- p.40
Chapter 4.2.2.2 --- Gross injury score --- p.41
Chapter 4.2.2.3 --- Cortex and hippocampus area --- p.41
Chapter 4.2.2.4 --- Blood cell counts --- p.42
Chapter 4.2.3 --- Effects of TPO on p7 severe damage model 1 week post-surgery --- p.43
Chapter 4.2.3.1 --- Body and brain weights --- p.43
Chapter 4.2.3.2 --- Gross injury score --- p.43
Chapter 4.2.3.3 --- Cortex area --- p.44
Chapter 4.2.3.4 --- Blood cell counts --- p.44
Chapter 4.2.4 --- Effects of TPO on p7 severe damage model 3 week post-surgery --- p.45
Chapter 4.2.4.1 --- Body and brain weights --- p.45
Chapter 4.2.4.2 --- Gross injury score --- p.46
Chapter 4.2.4.3 --- Blood cell counts --- p.46
Chapter 4.2.4.4 --- Functional outcomes --- p.46
Chapter 4.2.5 --- Effects of TPO on pl4 severe damage model 1 week post-surgery --- p.47
Chapter 4.2.5.1 --- Body and brain weights --- p.47
Chapter 4.2.5.2 --- Gross injury score --- p.48
Chapter 4.2.5.3 --- Cortex area --- p.48
Chapter 4.2.5.4 --- Blood cell counts --- p.49
Chapter 4.3 --- Discussion --- p.49
Chapter Chapter 5 --- Effects of thrombopoietin on the proliferation of primary mouse neural stem/ progenitor cells in culture --- p.83
Chapter 5.1 --- Summary of experimental settings --- p.83
Chapter 5.2 --- Results --- p.83
Chapter 5.2.1 --- Effect of EGF or bFGF withdrawal on NSP proliferation --- p.84
Chapter 5.2.2 --- Dose effect of TPO treatment on NSP proliferation --- p.85
Chapter 5.2.3 --- Effect of hypoxia --- p.85
Chapter 5.2.4 --- Effect of TPO treatment in combination with hypoxia --- p.86
Chapter 5.2.5 --- Detection of neural progenitor cell marker --- p.87
Chapter 5.3 --- Discussion --- p.88
Chapter Chapter 6 --- General discussion --- p.101
Bibliography --- p.106
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"Effects of thrombopoietin on the protection against doxorubicin-induced cardiotoxicity." 2006. http://library.cuhk.edu.hk/record=b5893012.
Full textAbstract:
To Man Yin.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.
Includes bibliographical references (leaves 85-105).
Abstracts in English and Chinese.
Abstract (in English) --- p.i
(in Chinese) --- p.iv
Acknowledgements --- p.vi
Publications --- p.viii
Table of Contents --- p.ix
List of Tables --- p.xii
List of Figures --- p.xiii
List of Abbreviations --- p.xiv
Chapter CHAPTER 1: --- General Introduction --- p.1
Chapter Section 1.1 --- Background and Clinical Application of Anthracylines --- p.1
Chapter Section 1.2 --- DOX-induced Cardiotoxicity --- p.3
Chapter 1.2.1 --- Types of Cardiotoxicity --- p.4
Chapter 1.2.1.1 --- Acute Cardiotoxicity --- p.4
Chapter 1.2.1.2 --- Chronic Cardiotoxicity --- p.5
Chapter 1.2.2 --- Subcellular Effects of DOX --- p.6
Chapter 1.2.2.1 --- Ultrastructural Lesions --- p.6
Chapter 1.2.2.2 --- Effects on Mitochondrial Functions --- p.7
Chapter 1.2.2.3 --- Effects on Sarcoplasmic reticulum (SR) Functions --- p.8
Chapter Section 1.3 --- Mechanisms of DOX-induced Cardiotoxicity --- p.8
Chapter 1.3.1 --- Formation of Free Radicals --- p.9
Chapter 1.3.1.1 --- Generation of Free Radicals by DOX --- p.10
Chapter 1.3.1.2 --- Cardiac damage by Free radicals --- p.12
Chapter 1.3.2 --- Induction of Apoptosis --- p.14
Chapter 1.3.2.1 --- Characteristics and Pathway of Apoptosis --- p.14
Chapter 1.3.2.2 --- Mitochondria and Apoptosis --- p.15
Chapter 1.3.2.3 --- Caspases and Apoptosis --- p.17
Chapter 1.3.2.4 --- Apoptosis and DOX-induced Cardiotoxicity --- p.18
Chapter Section 1.4 --- Strategies to Reduce DOX-induced Cardiotoxicity --- p.19
Chapter 1.4.1 --- Dosage optimization and Schedule modification --- p.19
Chapter 1.4.2 --- Anthracycline Analogues --- p.21
Chapter 1.4.3 --- Cardioprotective Agents --- p.21
Chapter Section 1.5 --- Thrombopoietin --- p.23
Chapter CHAPTER 2: --- Hypotheses and Objectives --- p.30
Chapter CHAPTER 3: --- Methodology --- p.33
Chapter Section 3.1 --- Methods --- p.33
Chapter 3.1.1 --- Culture of Rat H9C2 Myoblast Cell Line and Primary Neonatal Rat Cardiomyocytes --- p.33
Chapter 3.1.1.1 --- Maintenance of Cell Line --- p.33
Chapter 3.1.1.2 --- Culture of Primary Neonatal Rat Cardiomyocytes --- p.34
Chapter 3.1.2 --- Effects of Thrombopoietin on Cell Viability of Rat H9C2 Myoblast Cell Line and Beating Rates of Primary Rat Cardiomyocytes --- p.35
Chapter 3.1.2.1 --- Cell Viability assay --- p.35
Chapter 3.1.2.2 --- Beating Rate of Primary Beating Cardiomyocytes --- p.36
Chapter 3.1.3 --- Effects of Thrombopoietin on the Protection against DOX-induced Heart Injury In Vivo --- p.36
Chapter 3.1.3.1 --- Animals --- p.36
Chapter 3.1.3.2 --- Experimental Protocol --- p.37
Chapter 3.1.3.3 --- Echocardiography --- p.38
Chapter 3.1.3.4 --- Blood Cell Counts --- p.39
Chapter 3.1.3.5 --- Histopathology --- p.39
Chapter 3.1.4 --- Effects of Thrombopoietin on Apoptosis and Mitochondrial Integrity of Rat H9C2 Myoblast Cell Line and Apoptosis In Vivo --- p.40
Chapter 3.1.4.1 --- Determination of Externalized Phosphatidylserine --- p.40
Chapter 3.1.4.2 --- Determination of Active Caspase-3 Expression --- p.41
Chapter 3.1.4.3 --- Assessment of Mitochondrial Integrity --- p.42
Chapter 3.1.4.4 --- TUNEL assay --- p.43
Chapter 3.1.5 --- Statistical Analysis --- p.44
Chapter CHAPTER 4: --- Effects of Thrombopoietin on Cell Viability of Rat H9C2 Myoblast Cell Line and Beating Rates of Primary Neonatal Rat Cardiomyocytes --- p.46
Chapter Section 4.1 --- Results --- p.46
Chapter 4.1.1 --- Effects of TPO on DOX-induced Cell Death --- p.46
Chapter 4.1.2 --- Effects of TPO on the Beating Rates of Primary Cardiomyocytes --- p.47
Chapter Section 4.2 --- Discussion --- p.47
Chapter CHAPTER 5： --- Effects of Thrombopoietin on the Protection Against DOX-induced Heart Injury In Vivo --- p.54
Chapter Section 5.1 --- Results --- p.54
Chapter 5.1.1 --- General Observations and Survival --- p.54
Chapter 5.1.2 --- Blood Cell Counts --- p.55
Chapter 5.1.3 --- Cardiac Functions by Echocardiography --- p.56
Chapter 5.1.4 --- Gross Anatomic Changes and Pathology of the Myocardium --- p.57
Chapter Section 5.2 --- Discussion --- p.58
Chapter CHAPTER 6: --- Effects of Thrombopoietin on Apoptosis and Mitochondrial Integrity of H9C2 Cell Line and Apoptosis In Vico --- p.69
Chapter Section 6.1 --- Results --- p.69
Chapter 6.1.1 --- Determination of Externalized Phosphatidylserine --- p.69
Chapter 6.1.2 --- Determination of Active Caspase-3 Activity --- p.70
Chapter 6.1.3 --- Assessment of Mitochondrial Membrane Potential --- p.70
Chapter 6.1.4 --- Determination of Apoptosis by TUNEL assay --- p.72
Chapter Section 6.2 --- Discussion --- p.72
Chapter CHAPTER 7： --- General Discussion and Conclusion --- p.83
References --- p.85
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Schulze, Harald [Verfasser]. "Biochemische Untersuchungen zur Signaltransduktion des Thrombopoietin-Rezeptors c-Mpl in Thrombozyten / von Harald Schulze." 1999. http://d-nb.info/957851413/34.
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Lee, Yeojin. "Extrinsic regulation of Hematopoietic Stem Cells in the fetal liver." Thesis, 2021. https://doi.org/10.7916/d8-nx49-n324.
Full textAbstract:
Hematopoietic stem cells (HSCs) lie at the top of the hematopoietic hierarchy and give rise to all mature blood cells. They are tightly regulated not only by cell-intrinsic but also cell-extrinsic mechanisms that allow HSCs to respond to dynamic physiological demands of the body. HSCs build the hematopoietic system during development and maintain homeostasis in adults by changing their properties according to different needs. A niche is the microenvironment where HSCs reside and receive extrinsic regulation. Understanding the niche is crucial for elucidating how HSCs are regulated by extrinsic cues. During mammalian development, HSCs pass through several different niches, among which the liver is the major site for their rapid expansion and maturation. The fundamental question of what cells constitute the fetal liver niche in vivo remains largely elusive. It is also unclear whether and how cell-extrinsic maintenance mechanisms accompany changes in HSC properties during ontogeny. Here, I genetically dissected the cellular components of the HSC niche in the fetal liver by identifying the cellular source of a key cytokine, stem cell factor (SCF). In addition, I found that HSCs switch to depend on thrombopoietin (TPO), another key factor, during ontogeny and uncovered the mechanism by which HSCs gain this dependence.
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Rose, Stefanie [Verfasser]. "Der Effekt von Interferon alpha auf Thrombozyten und Thrombopoietin in Abhängigkeit vom Fibrosegrad bei Patienten mit chronischer Hepatitis C / vorgelegt von Stefanie Rose." 2004. http://d-nb.info/974923974/34.
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Byts, Nadiya. "Signalling of hematopoietic growth factors in mammalian neural cells." Doctoral thesis, 2007. http://hdl.handle.net/11858/00-1735-0000-0006-B36E-9.
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van, Eeuwijk Judith Martina Maria. "Studies on thrombopoiesis and spleen tyrosine kinase-mediated signaling in platelets." Doctoral thesis, 2018. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-142933.
Full textAbstract:
In mammals, anucleate blood platelets are constantly produced by their giant bone marrow (BM) progenitors, the megakaryocytes (MKs), which originate from hematopoietic stem cells. Megakaryopoiesis and thrombopoiesis have been studied intensively, but the exact mechanisms that control platelet generation from MKs remain poorly understood. Using multiphoton intravital microscopy (MP-IVM), thrombopoiesis and proplatelet formation were analyzed in the murine BM in real-time and in vivo, identifying an important role for several proteins, including Profilin1, TRPM7 and RhoA in thrombopoiesis. Currently, it is thought that blood cell precursors, such as MKs, migrate from the endosteal niche towards the vascular niche during maturation. In contrast to this paradigm, it was shown that MKs are homogeneously distributed within the dense BM blood vessel network, leaving no space for vessel-distant niches. By combining results from in vivo MP-IVM, in situ light-sheet fluorescence microscopy (LSFM) of the intact BM as well as computational simulations, surprisingly slow MK migration, limited intervascular space and a vessel-biased MK pool were revealed, contradicting the current concept of directed MK migration during thrombopoiesis. Platelets play an essential role in hemostasis and thrombosis, but also in the pathogenesis of ischemic stroke. Ischemic stroke, which is mainly caused by thromboembolic occlusion of brain arteries, is among the leading causes of death and disability worldwide with limited treatment options. The platelet collagen receptor glycoprotein (GP) VI is a key player in arterial thrombosis and a critical determinant of stroke outcome, making its signaling pathway an attractive target for pharmacological intervention. The spleen tyrosine kinase (Syk) is an essential signaling mediator downstream of GPVI, but also of other platelet and immune cell receptors. In this thesis, it was demonstrated that mice lacking Syk specifically in platelets are protected from arterial thrombus formation and ischemic stroke, but display unaltered hemostasis. Furthermore, it was shown that mice treated with the novel, selective and orally bioavailable Syk inhibitor BI1002494 were protected in a model of arterial thrombosis and had smaller infarct sizes and a significantly better neurological outcome 24 h after transient middle cerebral artery occlusion (tMCAO), also when BI1002494 was administered therapeutically, i.e. after ischemia. These results provide direct evidence that pharmacological Syk inhibition might become a safe therapeutic strategy. The T cell receptor chain-associated protein kinase of 70 kDA (Zap-70) is also a spleen tyrosine kinase family member, but has a lower intrinsic activity compared to Syk and is expressed in T cells and natural killer (NK) cells, but not in platelets. Unexpectedly, arterial thrombus formation in vivo can occur independently of Syk kinase function as revealed by studies in Sykki mice, which express Zap-70 under the control of intrinsic Syk promoter elementsIn Säugetieren werden kernlose Thrombozyten durch ihren riesigen Knochenmark- (KM-) Vorläuferzellen, die Megakaryozyten (MK), die von hämatopoetischen Stammzellen stammen, ständig produziert. Megakaryopoese und Thrombopoese wurden schon intensiv untersucht, aber die genauen Mechanismen, die die Thrombozytenproduktion aus MK kontrollieren, bleiben weitgehend unverstanden. Mittels Multiphotonen-Intravitalmikroskopie (MP-IVM) wurden Thrombopoese und Proplättchenbildung im murinen KM in Echtzeit in vivo untersucht. Dadurch wurde eine wichtige Rolle für die Proteine Profilin1, TRPM7 und RhoA in der Thrombopoese identifiziert. Derzeit wird angenommen, dass Blutzellvorläufer, wie MK, während der Reifung von der endostalen Nische in Richtung der Gefäßnische migrieren. Im Gegensatz zu diesem Paradigma wurde hier gezeigt, dass MK homogen innerhalb des dichten KM Blutgefäßnetzes verteilt sind, so dass kein Raum für Gefäß-ferne Nischen besteht. Durch Ergebnisse von in vivo MP-IVM, in situ Licht-Blatt-Fluoreszenzmikroskopie (LSFM) des intakten KM sowie Computersimulationen wurden eine überraschend langsame MK-Migration, ein begrenzter intervaskulärer Raum und eine asymmetrische MK-Verteilung gezeigt, was im Widerspruch zum derzeitig akzeptierten Konzept der gerichteten MK-Migration während der Thrombopoese steht. Die Thrombozyten spielen eine wesentliche Rolle nicht nur bei der Hämostase und Thrombose, sondern auch in der Pathogenese des ischämischen Schlaganfalls. Der ischämische Schlaganfall, der vor allem durch einen thromboembolischen Verschluss von Gehirnarterien verursacht wird, ist eine der häufigsten Ursachen für Tod und Behinderung weltweit und die Behandlungsmöglichkeiten sind sehr eingeschränkt. Der thrombozytäre Kollagenrezeptor Glykoprotein (GP) VI ist ein wichtiger Faktor in der arteriellen Thrombose und trägt entscheidend zur Pathogenese des ischämischen Schlaganfalls bei, sodass dessen Signalweg ein attraktives Ziel für pharmakologische Interventionen darstellen könnte. Die spleen tyrosine kinase (Syk) ist ein wichtiges Molekül im GPVI-Signalweg, aber auch in den Signalkaskaden von anderen Thrombozyten- und Immunzellrezeptoren. Es wurde nachgewiesen, dass Mäuse mit einer thrombozytären Syk-Defizienz, vor arterieller Thrombusbildung und ischämischem Schlaganfall geschützt sind, aber unveränderte Hämostase zeigen. Darüber hinaus wurde gezeigt, dass Mäuse, die mit dem neuartigen, selektiven und oral bioverfügbaren Syk-Inhibitor BI1002494 behandelt wurden, geschützt sind in einem Modell der arteriellen Thrombose. Auch hatten sie kleinere Infarkte und eine deutlich bessere neurologische Funktion 24 Stunden nach der transienten Arteria cerebri media Okklusion (tMCAO), auch wenn BI1002494 therapeutisch, d.h. nach der Ischämie, verabreicht wurde. Diese Ergebnisse deuten darauf hin, dass die pharmakologische Hemmung von Syk eine sichere therapeutische Strategie bei Schlaganfall sein könnte. Der T-Zell Rezeptor -chain-associated protein kinase of 70 kDa (Zap-70) ist auch ein spleen tyrosine kinase-Familienmitglied, hat aber eine geringere intrinsische Aktivität im Vergleich zu Syk und wird in T-Zellen und natural killer (NK) Zellen exprimiert, nicht aber in Thrombozyten. Studien in Sykki Mäusen, die unter der Kontrolle der intrinsischen Syk Promotorelemente Zap-70 exprimieren, ergaben, dass die arterielle Thrombusbildung in vivo unabhängig von der Syk-Kinasefunktion stattfinden kann