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1
Is'Harc, Hayaatun. "JAK/STAT signalling." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272414.
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Dawson, M. A. F. "JAK-STAT signalling at chromatin." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598423.
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The aim of my work was to explore the possibility that the mammalian JAK2 signalling pathway influences the structure and function of chromatin. I have demonstrated that JAK2 is present in the nucleus of both human haematopoietic cell lines and primary cells. My results suggest that JAK2 functions as a histone tyrosine kinase and phosphorylates histone H3 at tyrosine-41 (H3Y41). This novel histone modification, the first described tyrosine phosphorylation on any of the non-variant histones, regulates the binding of heterochromatin protein 1-alpha (HP1α) at a new binding site on chromatin. HP1α uses its chromo-shadow domain to bind the H3Y41 region. Phosphorylation of H3Y41 by JAK2 reduces its affinity for chromatin. This reciprocal relationship was given a functional context by demonstrating its relationship to the expression of a key haematopoietic oncogene Imo2. Genome-wide studies demonstrate that H3Y41ph is present at the 5’ end of genes and is highly correlated with active transcription. This is the first comprehensive genome wide mapping of a histone phosphorylation mark and potentially highlights a role for this novel modification in the regulation of transcription. H3Y41ph was also present at specific cis-regulatory elements on JAK2-STAT5 target genes and genome-wide mapping of STAT5 binding confirmed that STAT5 binding and H3Y41ph was coincident at a significant number of sites within the human genome. This interesting observation suggests that canonical JAK2-STAT5 signalling is not confined to the cytoplasma but also occurs at chromatin. These findings extend the existing paradigm of JAK-STAT signalling and provide a platform for a better understanding of this critical signalling pathway, which is important in both normal development and oncogenesis.
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Broughton, Nicola Ann. "Specificity in JAK/STAT signal transduction." Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300540.
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Zhu, Wei. "Negative regulation of JAK/STAT pathway /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3112843.
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Vogt, Katja L. "Endocytic regulation of JAK/STAT signalling." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6655/.
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Moore, Rachel. "Regulation of JAK/STAT signalling by endocytosis." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22459/.
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The JAK/STAT pathway is a highly evolutionarily conserved signal transduction pathway, whose activation can lead to a broad range of cellular outcomes. The pathway is used repeatedly during multiple developmental stages and in adult tissue, and therefore tight regulation is required to enable accurate responses in a context specific manner. Internalisation and endocytic trafficking of signalling components provides a mechanism whereby spatial compartmentalisation can enable distinct signalling outputs. Within this study I have investigated the role of endocytosis in the regulation of the Drosophila melanogaster JAK/STAT pathway, and demonstrated that internalisation and endocytic trafficking differentially regulates target genes. Although the JAK/STAT pathway is transcriptionally competent and can regulate the expression of particular targets when the activated receptor is at the cell surface, receptor endocytosis and localisation to distinct endosomes is required for the expression of other targets. This appears to be context-dependent, as high levels of ligand stimulation overcomes endocytic regulation. STAT92E, the Drosophila JAK/STAT transcription factor, is a target of endocytic regulation. Although it is efficiently activated and undergoes nuclear translocation when endocytosis is perturbed, it is not capable of regulating a subset of target genes and therefore further STAT92E interacting partners and/or post translational modification must be required to fine-tune its transcriptional competency during endocytic trafficking. Utilising mass spectrometry I identified a novel STAT92E phosphorylation site, at threonine 702. Mutation of this threonine to prevent its phosphorylation, resulted in inhibition of STAT92E signalling and nuclear translocation, and also prevented phosphorylation of a highly conserved tyrosine residue at position 704, which is crucial for ligand activated JAK/STAT signalling outputs. Therefore, this study has enhanced our understanding of mechanisms that can modulate JAK/STAT activity. I have revealed an important role for endocytosis in fine- tuning Drosophila JAK/STAT signalling outputs and also identified a novel phosphorylation site which is crucial in the activity of STAT92E.
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Leal, Cervantes Ana Irene. "Transcriptional consequences of Jak-Stat signalling in haematopoiesis." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709253.
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Röder, Sabine. "Signaltransduktion durch JAK-STAT-Moleküle bei der Polyzythämia vera." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972175741.
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Moubarak, Patricia. "Expression und Regulation von JAK/STAT-Proteinen im Pankreas." Diss., lmu, 2006. http://nbn-resolving.de/urn:nbn:de:bvb:19-53862.
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Pean, Claire. "JAK-STAT pathway in the control of mycobacterial infections." Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/jakstat-pathway-in-the-control-of-mycobacterial-infections(cb788a0d-1c53-4f5c-8513-64c8cb50e08e).html.
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Though mammalian JAKs and STATs have been extensively studied over the past 20 years, many aspects of their in vivo function remain unclear. In particular, their roles in control of infection with pathogens remain murky and confusing. One difficulty in understanding how these pathways regulate inflammation is the presence of complex compensatory mechanisms between the different JAK and STAT proteins. In the Dionne lab, we use the fruit-fly Drosophila melanogaster as a model to study the in vivo functions of the JAK/STAT pathway in mycobacterial infection. Flies contain only one JAK (hop), one STAT (STAT92E), and three identified interleukin-like signals to activate signalling (upd, upd2, upd3). I show that, in Drosophila, the STAT-activating cytokine Upd3 is harmful to the host upon mycobacterial infection. Flies lacking upd3, or in which the JAk/STAT pathway is inhibited in phagocytes, show improved survival, decreased mycobacterial numbers, and delayed immune cell death. Strikingly, I find that JAK/STAT signalling acts in concert with other inflammatory signals to regulate expression of Atg2 in Drosophila phagocytes. In isolation or upon infection, STAT activation inhibits Atg2 expression and the ability of other, unknown signals to promote Atg2 expression. Increased Atg2 expression, as is seen in infected animals lacking either the cytokine Upd3 or STAT92E, promotes killing of intracellular bacteria and accumulation of large lipid droplets of unusual shape. I suggest an autophagy-independent mechanism by which Atg2 could reduce bacterial growth, involving the control of lipid body morphology. In this thesis, I show a mechanism by which JAK/STAT controls bacterial growth through inhibition of autophagy gene expression and demonstrate that this inhibition is detrimental to the survival of the host. In addition, I demonstrate that upd3 signalling is also required for glucose homeostasis suggesting a role for Upd3 in regulating gluconeogenesis and glycolysis.
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Devergne, Olivier. "Étude de la voie JAK/STAT chez Drosophila melanogaster." Nice, 2006. http://www.theses.fr/2006NICE4030.
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Chez les mammifères, la voie de signalisation JAK/STAT est activée en réponse aux cytokines et aux facteurs de croissance. Son activation stimule la prolifération, la différentiation, la migration cellulaire ainsi que l'apoptose. Nous montrons que la voie JAK/STAT et son récepteur Domeless (Dome), un récepteur de la famille des récepteurs aux IL-6, sont requis pour la différenciation et la migration des cellules de la bordure, un modèle d'invasion cellulaire qui se déroule au cours de l'ovogenèse chez la drosophile. Nous nous sommes ensuite intéressés aux mécanismes impliqués dans le contrôle de la voie de signalisation JAK/STAT. En effet, la voie de signalisation commence à être bien connue, en revanche le rôle de l'endocytose des récepteurs aux cytokines sur la transduction du signal est peu caractérisé. Grace à des analyses génétiques in vivo et des expériences en culture cellulaire, nous montrons que la fixation du ligand induit l'endocytose clathrine dépendante du complexe récepteur/ligand. Après internalisation, ces complexes traversent les différents compartiments endosomaux et sont dirigés vers le lysosome afin d'y être dégradés. Cette dégradation permet la désensibilisation de la voie JAK/STAT. De façon intéressante, le blocage de l'endocytose de Dome, grace à un mutant de la clathrine, entraine la diminution de l'activité de la voie JAK/STAT, suggérant que le recrutement de la clathrine et la formation des vésicules de bourgeonnement sont requis pour l'activation de la voie. La fixation du ligand n'est pas suffisante. De plus, le blocage du trafic au niveau de différents compartiments endosomaux, en utilisant des mutants rab5, hrs ou dor entraine également une inhibition de la voie JAK/STAT indiquant que l'endocytose et le trafic intracellulaire sont nécessaires pour la transduction du signal. Nos résultats révèlent ainsi un rôle essentiel de l'endocytose dépendante de la clathrine pour la transduction du signal in vivoIn mammals, the JAK/STAT signaling pathway is activated in response to cytokines and growth factors to control blood cell development, proliferation and cell determination. We show that the JAK/STAT pathway and its receptor Domeless (Dome), a receptor of the IL-6 receptor family, are required for the differentiation and the migration of border cells during drosophila oogenesis which represent a powerful model to study cell invasion. We then became interested into the role of endocytosis as a mechanism to control JAK/STAT signaling. Indeed, the transduction machinery in several models is well known, however the function of cytokine receptor endocytosis on signaling remains poorly characterized. Using both in vivo genetic analysis and cell culture assays, we show that ligand-binding induces clathrin-dependent endocytosis of receptor-ligand complexes which traffic through the endosomal compartment and are targeted to the lysosome for degradation, leading to the desensitization of JAK/STAT activity. Surprisingly, blocking endocytosis of Dome using clathrin mutants led to a downregulation of JAK/STAT signalling, suggesting that clathrin recruitment and formation of budding vesicles are required for JAK/STAT signaling and that ligand binding is not sufficient to activate the pathway. In addition, disrupting endocytosis of Dome in distinct endosomal compartments, using rab5, hrs, or dor mutants, also led to a reduction of signaling indicating that endocytosis and intracellular trafficking are necessary for signaling. Altogether, our data reveal an essential role of clathrin dependent endocytosis for JAK/STAT signalling in vivo
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Chen, Qian. "THE INTERACTIONS BETWEEN JAK/STAT SIGNALING LIGANDS IN DROSOPHILA MELANOGASTER." UKnowledge, 2014. http://uknowledge.uky.edu/biology_etds/23.
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The development of multi-cellular organisms requires extensive cell-cell communication to coordinate cell functions. However, only a handful of signaling pathways have emerged to mediate all the intercellular communications; therefore, each of them is under an array of regulations to achieve signaling specificity and diversity. One such signaling pathway is the Janus Kinase/ Signal Transducer and Activator of Transcription (JAK/STAT) pathway, which is the primary signaling cascade responding to a variety of cytokines and growth factors in mammals and involved in many developmental processes. This signaling pathway is highly conserved between mammals and Drosophila, but the Drosophila JAK/STAT pathway possesses only three ligands: Unpaired (Upd), Upd2 and Upd3. Co-localized expression patterns of the ligands at several developmental stages raise the possibility that they physically interact. This work was aimed at testing the protein-protein interactions between Upd-family ligands and exploring possible outcomes of ligand oligomerization.
Physical interactions between Upd-family ligands were tested using a Bimolecular Fluorescence Complementation (BiFC) assay. The data suggested that homotypic interactions of Upd2 and Upd3 were stronger than their respective heterotypic interactions with Upd, and the homotypic interaction between Upd molecules was the weakest. In addition, the homotypic interaction of Upd3 was confirmed using yeast two-hybrid interaction assays. To identify protein domains critical for Upd3/Upd3 interaction, a series of poly-alanine substitutions were made to target the 6 conserved domains of Upd3. All 6 substitutions altered the strength of Upd3/Upd3 interaction and drastically reduced Upd3-induced JAK signaling activity. In addition, poly-alanine substitutions of some domains also affected Upd3 extracellular localization or protein accumulation.
Potential outcomes of interactions between Upd-family ligands were tested both in vitro and in vivo. The interaction between Upd and Upd3 did not significantly change the level of JAK signaling activity. However, loss of Upd3 restricted the distribution of Upd in egg chambers and consequently altered the follicle cell composition. Therefore, Upd/Upd3 interaction is likely to affect the range rather than the intensity of JAK signaling in egg chambers. In summary, this study suggested the possibility of ligand oligomerization as a mechanism for regulating signaling pathways in order to achieve signaling specificity and diversity during development.
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Han, Ho-chun, and 韓浩俊. "JAK-STAT pathway as potential target of acute myeloid leukemia." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B50534208.
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Acute myeloid leukemia (AML) is a group of heterogeneous diseases characterized by an abnormal increase in myeloblasts. Despite intensive chemotherapy and allogeneic bone marrow transplantation, the treatment outcome of AML remains unsatisfactory, with a cure rate of only about 30%. Therefore, novel therapeutic strategies targeting the pathogenetic pathways of leukemia initiation and progression are needed. Using intracellular phospho-flow analysis with normal bone marrow as reference, we detected an increase in phosphorylated-STAT5 (pSTAT5) in three leukemic cell lines (K562, KG-1 and ML-2) and 15 primary AML samples. Treatment with specific JAK2 inhibitor TG101209 and JAK2/3 inhibitor AG490 significantly reduced pSTAT5 level and leukemia cell growth associated with an increase in apoptosis and decrease in cellular proliferation. The clonogenic activities of these leukemia cell lines were also significantly reduced. Furthermore, treatment with these inhibitors in K562 and KG-1 also significantly reduced the WNT signaling activity, as enumerated by the TOP/FLASH luciferase assay. In addition, genes associated with oncogenic potential and anti-apoptosis were significantly reduced, consistent with the pathogenetic role of JAK-STAT pathway.
In summary, the present study highlighted the importance of the JAK2-STAT5 signaling pathway in sustaining AML. The results may open up a new avenue whereby new therapeutic strategies targeting AML can be designed.published_or_final_version
Medicine
Master
Master of Philosophy
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Stec, Wojciech. "Molecular analysis of the Drosophila JAK/STAT pathway receptor complex." Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/4509/.
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The JAK/STAT signalling pathway plays a central role in numerous biological processes contributing to development and maintenance of homeostasis. Drosophila melanogaster offers a conserved JAK/STAT pathway with much lower redundancy. For this reason, the fruit fly was used as a model organism to investigate genetic interactions and functions of the JAK/STAT pathway in the context of the whole organism. However, very little is known regarding the molecular mechanisms governing the Drosophila JAK/STAT pathway. Here, we present a molecular analysis of the sole receptor of the JAK/STAT pathway in Drosophila, Dome. We show that Dome shares characteristics with different sub-families of mammalian cytokine receptors. Specifically, the identified JAK binding site in Dome is reminiscent of that found in IFN? receptor, while constitutive endocytosis leading to lysosomal degradation shares similarities with the Leptin receptor. An increase in tyrosine phosphorylation and a shift in the ubiquitination pattern of the receptor in response to ligand binding are also described. Furthermore, the structure-function analysis of socs36E, the only SOCS-like protein in the Drosophila genome that can potently suppress the JAK/STAT pathway, revealed two independent mechanisms of action. Firstly, SOCS36E affects stability of the receptor, most likely by forming ubiquitin ligase via the SOCS box domian, a mechanism well described for all mammalian SOCS proteins. Secondly, regulation of Dome phosphorylation by the N-terminal domain of SOCS36E contributes to suppression of the JAK/STAT pathway in a SOCS box independent manner. Finally, two alleles of the Drosophila JAK that give rise to a phenotype reminiscent of human leukaemia, hopTuml and hopT42, are shown to increase transcriptional activity of the pathway reporter without increasing phosphorylation of STAT. Both mutations cause constitutive activation of the kinase independently of the receptor. Moreover, autophosphorylation kinetics of both mutants are unaltered, compared to the wild-type Hop, suggesting non-canonical signalling to be the underlying cause of oncogenicity.
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Thomas, Sally J. "Genetic and chemical modulators of JAK/STAT signalling in cancer." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/13230/.
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Activation of JAK/STAT signalling is a feature of many haematological malignancies and solid tumours. Better understanding of the molecular events contributing to JAK/STAT pathway activation, and a greater range of therapies acting on the pathway, should lead to improved treatment options for patients with malignancies associated with activation of the pathway. This work builds on screens that identified genes and drugs which modulate JAK/STAT signalling in the fruit fly Drosophila melanogaster, to determine whether these effects occur in the conserved human pathway. The gene ANKHD1 (Ankyrin Repeat and KH Domain containing 1) has been identified as a positive regulator of JAK/STAT signalling in Drosophila, but there has been little investigation of ANKHD1 in human tissues. I show that ANKHD1 protein is expressed in normal blood cells and the malignant clone of cells in acute leukaemias. I also show that ANKHD1 protein is expressed in the skin cancer malignant melanoma, where it is found in the nucleus and cytoplasm in a range of histological sub-types of melanoma. Methotrexate was identified as a selective suppressor of JAK/STAT signalling in a screen in Drosophila cells. No interaction between methotrexate and JAK/STAT signalling has previously been described. I demonstrate that methotrexate suppresses JAK/STAT signalling in human cell lines at drug concentrations equivalent to those measured in patients, suggesting that suppression of JAK/STAT signalling may contribute to the mechanism-of-action of methotrexate in inflammatory conditions. Furthermore, the effect occurs when the pathway is activated by the JAK2V617F mutation found in patients with myeloproliferative neoplasms (MPNs). The potential of methotrexate as a treatment for patients with MPNs is investigated in primary cells obtained from patients with myelofibrosis.
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Kalymbetov, Anuar [Verfasser]. "Role of JAK/STAT signalling pathway in PAH / Anuar Kalymbetov." Gießen : Universitätsbibliothek, 2016. http://d-nb.info/1120270227/34.
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Giedt, Michelle Suzanne. "JAK/STAT SIGNALING REGULATES GAMETOGENESIS AND AGE-RELATED REPRODUCTIVE MAINTENANCE." UKnowledge, 2018. https://uknowledge.uky.edu/biology_etds/52.
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Cell signaling is central to integration of internal and external cues that regulate development and homeostasis. Most development is thought of as pre-adult, but limited developmental processes occur in adults. Gametogenesis incorporates elements of both these facets, with a distinct developmental plan for gamete synthesis which is regulated by integration of homeostatic inputs such as nutrient status, and environmental cues. Signaling pathways integrate and transduce information from these cues to evoke a response. A decline in homeostasis and subsequent cues occurs over time, in the case of reproductive tissues leading to a progressive loss of fertility. The Janus Kinase and Signal Transducer and Activator of Transcription or Jak/Stat signaling pathway is conserved between vertebrates and invertebrates and is necessary for numerous functions needed to maintain organism and reproductive homeostasis, as well as contributing to various developmental events. The pathway in the fruit fly Drosophila melanogaster, is composed of a single receptor, Domeless, one Janus kinase, Hopscotch, one known effector, Stat92E, and the Unpaired family of ligands consisting of Upd, Upd2, and Upd3. Jak/Stat signaling is highly pleiotropic in both sexes with involvement in homeostasis and reproduction, making it an ideal model for studying the role of signaling in reproductive aging. Reduction of pathway activity in females results in a higher proportion of unfertilized eggs, which increases with age, and in males leads to a premature onset of infertility. Central to both is integration through cell signaling to evoke an appropriate response. This dissertation explores two of the requirements for Jak/Stat signaling: the pleiotropic requirement for Jak/Stat activity during oogenesis and male reproductive maintenance.
Jak/Stat functions from the beginning of oogenesis, in the stem cell niche. From there it participates in multiple functions including specification of a subset of somatic cells called the border cells through the polar cells, a pair of cells at either pole of the egg. Pathway stimulation in the border cells drives their migration with the polar cells to the oocyte boundary, where the polar cells each form an extension in a coordinated manner into the micropyle, the means for sperm entrance during fertilization. Loss of Jak/Stat activity in the border cells prevents border cell migration. While border cell migration has been well studied, polar cell involvement after completion of border cell migration is less well known. To investigate the requirements for polar cell activity and Jak/Stat activity after the completion of border cell migration, we reduced Jak/Stat signaling in the polar cells which, while having no effect on border cell migration, results in blocked micropyles due to loss of coordination of extensions during their outgrowth. Reduced function in the polar cells did not significantly affect expression of adhesion molecules. But, the loss of Stat92E is phenocopied by loss of DE-cadherin. Hence, these results indicate a previously unknown autocrine requirement for Jak/Stat activity in the polar cells.
The testes also have a continuous requirement for Jak/Stat activity for stem cell maintenance and differentiation of the germline into mature sperm. Reproductive maintenance not only requires sustained production of gametes, but reproductive tissues are also subject to deterioration of homeostatic functions that contribute to organismal aging. Males from thirty-nine lines of the Drosophila Genetic Reference Panel (DGRP), a panel of inbred, fully sequenced lines, were screened for age at infertility. Data were used to perform a genome-wide association study (GWAS) to identify the genetic architecture of reproductive aging. Candidate variants associated with cell signaling regulators, genes with functions in maintaining cell homeostasis, and organism behavior were uncovered. Notably, several SNPs fell in and near Ptp61F, a negative regulator of Jak/Stat activity. While variants in the primary components of the Jak/Stat pathway were not identified, the general classes of candidate loci functions reflect the requirements for homeostasis, metabolism, and development that have been shown by other studies examining the genetics of aging and fecundity. Thus, we show that Jak/Stat has an amazing amount of pleiotropy that encompasses both the real-time functions of fertility and the time related process of aging.
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Tardif, Nicolas. "Mechanosignaling through Caveolae : A New Role for the Control of JAK-STAT Signaling." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS337/document.
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Les cavéoles sont des invaginations en forme de coupelle à la membrane plasmique. Ces organelles multifonctionnelles jouent entre autres, un rôle clé dans la mécano-protection et la signalisation cellulaire. En effet, les cavéoles ont la faculté de s’aplanir en réponse à l’augmentation de la tension membranaire, afin de protéger la cellule des contraintes mécaniques. Les cavéoles jouant un rôle clé dans la signalisation cellulaire, nous avions émis l’hypothèse que le cycle mécano-dépendent de désassemblage/réassemblage des cavéoles constitue un interrupteur mécanique de certaines voies de signalisation. Ce projet consiste à élucider le mécanisme moléculaire responsable du contrôle de la voie de signalisation JAK-STAT par la mécanique des cavéoles. Dans ces travaux, nous avons pu démontré que la cavéoline-1 (Cav1), un constitutant essentiel des cavéoles est libérée et devient hautement mobile au niveau de la membrane plasmique. Considérant les propriétés de signalisation de Cav1, Nous avons testé l’effet du désassemblage des cavéoles sur la signalisation cellulaire. Un criblage à haut débit, nous a permis identifié la voie de signalisation JAK- STAT stimulée par l’IFN-α comme voie modèle pour cette étude. En effet, la transduction du signal JAK-STAT induit par l’IFN-α est modulée par la mécanique des cavéoles. Afin de disséquer le mécanisme moléculaire responsable du contrôle de la signalisation JAK-STAT par la mécanique des cavéoles, nous avons déterminé le rôle de Cav1 dans ce contrôle. Nous avons observé que Cav1 est un régulateur négatif de la phosphorylation de STAT3 dépendante de la kinase JAK1. De plus, nous avons démontré que Cav1 interagit avec JAK1 en fonction de la tension membranaire. Nous avons également démontré que cette interaction Cav1-JAK1 fait intervenir le « scaffolding domain » de Cav1 (CSD), et que celui-ci est responsable de l’abolition de l’activité kinase de JAK1. Par conséquent, l’interaction de Cav1 avec JAK1 empêche l’activation de STAT3 par la kinase JAK1. Ces résultats démontrent que les cavéoles sont des organelles de mécano-signalisation, qui, lors d’un stress mécanique, libèrent de la Cav1 non cavéolaire capable d’inactiver la kinase JAK1, empêchant ainsi, la transduction du signal JAK-STATCaveolae are small cup-shaped plasma membrane invaginations. These multifunctional organelles play a key role in cell mechanoprotection and cell signaling. Indeed our laboratory reported that caveolae have the ability to flatten out upon membrane tension increase, protecting cells from mechanical strains. Since caveolae play a key role in cell signaling we hypothesized that the mechano-dependent cycle of caveolae disassembly/reassembly may constitute a mechanical switch for signaling pathways. In this project, we elucidated the molecular mechanism underlying the control of JAK-STAT signaling by caveolae mechanics. We showed that caveolin-1 (Cav1), an essential caveolar component is released and become highly mobile at the plasma membrane under mechanical stress. Considering that caveolae are important signaling hubs at the plasma membrane, we addressed the effects of the mechanical release of Cav1 on cell signaling. Using high throughput screening, we identified the JAK-STAT signaling pathway as a candidate. To further dissect the molecular mechanism underlying the control of JAK-STAT signaling by caveolae mechanics, we addressed the role of Cav1 in the control of JAK-STAT signaling stimulated by IFN-α. We found that Cav1 was a specific negative regulator of the JAK1 dependent STAT3 phosphorylation. Furthermore, the level of Cav1 interaction with JAK1 depended on mechanical stress. We could show that Cav1-JAK1 interaction was mediated by the caveolin scaffolding domain (CSD), abolishing JAK1 kinase activity, hence, interfering with STAT3 activation upon IFN-α stimulation. Altogether our results show that caveolae are mechanosignaling organelles that disassemble under mechanical stress, releasing non-caveolar Cav1, which binds to the JAK1 kinase and inhibits its catalytic activity, preventing thereby JAK-STAT signal transduction
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Gandhi, Hetvi. "Early events in cytokine receptor signaling." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-135614.
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Ligand-activated signal transduction is a process critical to cell survival and function as it serves as a means of communication between the cells and their environment. Endocytosis is generally thought to down-regulate incoming signals by reducing the surface availability of receptors. However, increasing evidence in many systems suggests a notion which is referred to as the „signalling endosome" hypothesis - that endocytosis can also actively contribute to signalling apart from clearance of activated receptors and thereby attenuation of signalling. The functional aspect of signalling endosomes has been well-characterized in several pathways including RTK and TGF-β signalling. There are, however, various other signalling pathways where the active mechanism of endocytotic regulation is yet to be understood.
In this study, we probe this aspect in the cytokine signalling system, where the receptors are known to internalize but the significance of such internalization and precise mechanism is unclear. My thesis aims to elucidate the function and molecular details of internalization of cytokine receptor using interleukin-4 receptor (IL-4R) signalling as a model. IL-4 and IL-13 ligands can induce assembly of three distinct complexes: IL4 induced IL-4Rα – IL-2Rγ (type I), IL-4 induced IL-4Rα – IL-13Rα1 (type II) or the IL-13 induced IL-13Rα1-IL-4Rα (type II). The formation of any of these complexes triggers signalling through the JAK/STAT pathway. However, models of how the oligomerization of the transmembrane receptors and activation takes place are very diverse and lack a clear molecular and biophysical understanding of the underlying receptor dynamics.
Previous results of the lab had shown that the affinities between subunits are low, precluding complex formation at the plasma membrane at physiological concentrations. In addition, IL-4R subunits localize in to endosomal structures adjacent to the plasma membrane. It had already been shown that the shared IL-4R subunit IL-2Rγ is internalized by a specific, actin dependent, Rac1/Pak1 regulated endocytosis route in the IL-2 context. We could show that pharmacological suppression of this endocytosis pathway also prevented IL-4 induced JAK/STAT signalling, placing endocytosis upstream of signalling.
Here I show using immuno-EM techniques that these endosomal structures are multivesicular bodies. Importantly, I could show that receptor subunits are highly enriched in the limiting membrane of these endosomes relative to the adjacent plasma membrane. Using quantitative loading assays I could furthermore demonstrate that this enrichment is achieved by constitutive internalization of receptors from the cell surface into cortical endosomes. The trafficking kinetics of the receptor subunits is independent of ligand occupancy. Pharmacological inhibition shows that receptors and ligand traffic via the previously identified Rac1/Pak1 pathway. Finally, Vav2 was identified as a candidate Guanine Exchange Factor (GEF) that may regulate Rac1 activity and thereby control the actin polymerization cascade driving IL-4R endocytosis. Immunoprecipitations showed that Vav2 interacts both with the cytoplasmic tail region of the receptors and the receptor associated 2 kinase JAK3. Vav2 may thus couple the receptor/JAK complexes to the Rac1/Pak1 mediated endocytosis route.
Taken together, our results suggests that stable „signalling endosomes‟ adjacent to the plasma membrane act as enrichment centres, where ligand and receptor concentrations are locally increased by constitutive trafficking. The confined environment of the endosome then compensates for the weak affinities between the ligand and receptor and facilitates ligand-mediated receptor dimerization. Importantly, overexpression of both type II IL-4R subunits renders signal transduction resistant to endocytosis inhibition, strongly suggesting that the critical factor effecting signalling is sufficient concentration, which the endosomes facilitate achieving. The endosomes are thus dispensable as signalling scaffolds when the receptors are in sufficient concentration, where activated receptors could interact with downstream pathway components.
Endocytosis thus provides a crucial means for the signalling process to overcome the thermodynamic hurdles for receptor oligomerization. In conclusion, our data propose a novel, purely thermodynamic role of endosomes in regulating cytokine receptor signalling not seen in any other signalling pathway.
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SILVA, Juan Luiz Coelho da. "Impacto clínico e laboratorial de mutações no gene ASXL1 em pacientes com neoplasias mieloproliferativas." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/19535.
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Algumas evidências destacam mutações no gene ASXL1 como um evento importante na evolução clínica de pacientes com neoplasias hematológicas, particularmente em leucemias mieloides agudas e síndrome mielodisplásicas. Contudo, seu impacto prognóstico em neoplasias mieloproliferativas (NMP) ainda é pouco explorado. Aqui, nós caracterizamos 208 pacientes com NMP cromossomo Filadélfia (Ph) negativo (policitemia vera, PV; trombocitemia essencial, TE; mielofibrose primária, MFP), de acordo com mutações no gene ASXL1, e correlacionamos esses achados com características clinico-laboratoriais desses pacientes. A pesquisa das mutações foi realizada por sequenciamento sanger, em que polimorfismos germinativos e mutações sinonímias foram excluídas das análises. Mutações no ASXL1 foram detectadas em 22/208 pacientes (10%), das quais quatro foram observadas em pacientes com PV (4/54; 7%), onze em pacientes com TE (11/123; 9%) e sete com MFP (7/31; 22%). As características clínicas e laboratoriais foram similares entre pacientes com ASXL1 mutado e não mutado. Quando as entidades foram avaliadas individualmente (PV, TE e MFP), observou-se associação entre mutações no ASXL1 e idade mais avançada em pacientes com TE (P = 0,049) e desenvolvimento de esplenomegalia em pacientes com MFP (P = 0,026). Com uma mediana de seguimento de 5,1 anos (IC95%: 4,5 a 7,3 anos), 136 pacientes (65%) desenvolveram algum tipo de manifestação clínica, sendo o desenvolvimento de complicações vasculares o mais frequente (n=54; 26%), seguido por esplenomegalia (n=47; 22%), eventos hemorrágicos (n=30; 14%) e trombose (n=21; 10%). Mutações no gene ASXL1 não foram associadas com o desenvolvimento das referidas manifestações. Dentro deste seguimento, apenas dois pacientes evoluíram para síndrome mielodisplásica e um para leucemia mieloide aguda, todos sem mutações no gene ASXL1.
Accumulating evidences report mutation in ASXL1 as an important predictor to clinical outcomes of patients with hematological malignancies, particularly acute myeloid leukemia and myelodysplastic syndrome. However, the prognostic impact in myeloproliferative neoplasm (MPN) remains underexplored. Here, we evaluated clinical and laboratory features of 208 Philadelphia negative MPN patients (polycythemia vera, PV; essential thrombocythemia, ET; primary myelofibrosis, PMF), according to mutations in ASXL1. Screening for ASXL1 mutations were performedby Sanger sequencing. Germline variations were excluded. ASXL1 mutations were detected in 22/208 patients (10%), of which four in PV patients (4/54-7%), 11 in ET patients (11/123-9%) and seven in PMF (7/31-22%). Baseline features were similar between ASXL1-mutated and non-mutated patients. Evaluated individually (PV, ET, PMF), we observed that ET patients harboring ASXL1 mutations were older (P = 0,049) than ASXL1 non-mutated patients. Similarly, PMF patients presented higher frequency of splenomegaly in ASXL1mutated group (P = 0,026). No other features were associated with ASXL1mutations. The median follow-up was 5,1 years (CI95%: 4,5-7,3 years). One hundred and thirty six patients (65%) developed some of the clinical common manifestations, which the most frequent was vascular complications (n=54; 26%), followed by splenomegaly (n=47; 22%), bleeding (n=30;14%) and thrombosis (n=21;10%). ASXL1 mutations were not associated with development of such events. In our cohort, only two patients have evolved for myelodysplastic syndrome and one for acute myeloid leukemia, all of them without mutations in ASXL1.
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Litterst, Claudia Monika. "Untersuchungen zur Funktion von Koaktivatoren in der JAK-STAT-vermittelten Transkriptionsaktivierung." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966005597.
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Park-Min, Kyung-Hyun. "The crosstalk between ITAM-associated receptors and Jak-STAT signaling pathways /." Access full-text from WCMC:, 2007. http://proquest.umi.com/pqdweb?did=1296119161&sid=8&Fmt=2&clientId=8424&RQT=309&VName=PQD.
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Wright, Victoria M. "Investigating the differential properties of the Drosophila JAK/STAT pathway ligands." Thesis, University of Sheffield, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555230.
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The JAK/STAT signalling cascade in vertebrates is activated in response to multiple cytokines and growth factors. By contrast, the Drosophila genome encodes for only three related JAK/STAT ligands, Upd, Upd2 and Upd3. It is hoped that identifying the differences in signalling stimulated by these three Updlike ligands will ultimately lead to a greater understanding of this disease-related pathway and its roles in development. Here, the analysis of the least well characterised of the Upd-like ligands, Upd3, is described. Upd3 is revealed as a secreted molecule that can activate JAK/STAT signalling both in tissue culture systems and in vivo. Also, potential sites of Upd3 expression are identified in both the adult Drosophila ovary and testis, in addition to expression in the larval eye disc and wing disc. Quantification of each of the Upd-like ligands in conditioned media allowed the ability of equal amounts of each ligand to be assessed for activation of the JAK/STAT pathway, revealing that Upd is the most potent ligand in this system. Furthermore, mixing of ligands in conditioned media revealed that the Upd-like ligands do not appear to act in a synergistic manner to activate signalling. In addition, RNAi screens were utilised in Drosophila KC167 cells to determine novel regulators of JAK/STAT signalling. Kinome and phosphatome screening identified 39 kinases and 10 phosphatases as potential modulators of the JAKISTAT pathway in response to stimulation by all three of the Upd-like ligands. Several of the hits identified as acting downstream of the Jak kinase, Hop, were screened for effects on JAK/STAT-mediated tumour formation in vivo. Of those screened, RNAi targeting, PPP4R2r, CG8878 and par-l were found to have significant effects on tumour formation, suggesting a role in JAK/STAT modulation and haematopoiesis.
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Tang, Lingfeng. "THE JAK/STAT PATHWAY IS REUTILIZED IN DROSOPHILA SPERMATOGENESIS." UKnowledge, 2014. http://uknowledge.uky.edu/biology_etds/27.
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In the Drosophila testis, sperm are derived from germline stem cells (GSCs) which undergo a stereotyped pattern of divisions and differentiation. The somatic cells at the tip of the testis form the hub, which is the niche for both the somatic cyst stem cells (CySCs) and GSCs. The hub expresses Upd, a ligand for the JAK/STAT pathway that has roles in the maintenance of CySCs and GSCs. Male mutants of upd3, another ligand of the JAK/STAT pathway, become sterile much earlier than the wild-type, leading to the hypothesis that similar to upd, upd3 also promotes the self-renewal of stem cells in testis. It was found here that upd3 is also expressed in the hub, and that mutants of upd3 have fewer CySCs and GSCs. Using a GFP reporter of the JAK/STAT pathway, it was found that the JAK/STAT pathway is not only activated in the stem cells, consistent with its known function in the maintenance of stem cells, but is also activated in the elongated cyst cells that encapsulate late stage differentiating spermatids. The reduction of JAK/STAT activity in the somatic cyst cells led to impaired spermatid individualization, a late stage of spermatogenesis during which the syncytial spermatids are separated. The impairment of individualization was shown by the loss of three characteristic structures: individualization complexes (ICs), cystic bulges (CBs), and waste bags (WBs). The failure of IC formation implies STAT activity is required for the initiation of individualization, and the loss of CBs and WBs suggests STAT activity is required for the progression of individualization. Activation of caspases in elongated spermatids is known to be required for individualization. The reduction of JAK/STAT activity in cyst cells almost completely eliminated the activation of two effector caspases: drICE and DCP-1. It was concluded that JAK/STAT activity in somatic cyst cells promotes individualization by stimulating caspase activity in spermatids. The JAK/STAT pathway is not only required for the maintenance of stem cells at the tip, but also required for individualization away from the tip during late differentiation, thus is reutilized in Drosophila spermatogenesis.
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Lachance, Catherine. "LES INTERMÉDIAIRES DE LA VOIE JAK / STAT DANS LES SPERMATOZOÏDES HUMAINS." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29583/29583.pdf.
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Ning, Shunbin, and Ling Wang. "Inactivation Of Type I IFN Jak-STAT Pathway In EBV Latency." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/6533.
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Epstein-Barr Virus (EBV) latent infection is associated with a variety of lymphomas and carcinomas. Interferon (IFN) Regulatory Factors (IRFs) are a family of transcription factors, among which IRF7 is the “master” regulator of type I IFNs (IFN-I) that defends against invading viruses. Robust IFN-I responses require a positive feedback loop between IRF7 and IFN-I. In recent years, we have discovered that IRF7 is significantly induced and activated by the principal EBV oncoprotein--Latent Membrane Protein 1 (LMP1); however, IRF7 fails to trigger robust IFN-I responses in EBV latency. We believe this intriguing finding is critical for EBV latency and oncogenesis, yet the underlying mechanism of this paradoxical phenomenon remains unclear. It is well known that tyrosine phosphorylation of most components of the IFN-I Jak-STAT pathway is essential for its signaling transduction. Thus, we have performed phosphotyrosine proteomics. We have found that the IFN-I Jak-STAT pathway is inactive due to the attenuated STAT2 activity, whereas the IFN-II Jak-STAT pathway is constitutively active, in EBV latency. We further confirmed these results by immunoblotting. This pilot study provides valuable information for the critical question regarding how the IRF7-mediated IFN-I response is evaded by EBV in its latency, and will prompt us to elucidate the underlying mechanisms.
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zhang, qifang. "Role of Jak/Stat pathway in the pathogenesis of breast cancer." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/41.
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The Jak/Stat signaling cascade mediates cell proliferation, differentiation, survival, apoptosis and immune responses. Aberrant activation of this pathway mediates neoplastic transformation and abnormal growth of many malignancies including breast cancer, the most common cancer among women, and the second leading cause of cancer deaths in women in United States. The mechanism by which the Jak/Stat pathway modulates the pathogenesis of breast cancer is unclear. This dissertation elucidates roles of Jak/Stat members that mediate the pathogenesis of breast cancer. For these studies, we used 4T1 mouse mammary tumor cells as a model which mimics human breast cancer. First, we investigated the role of Tyk2 tyrosine kinase in the pathogenesis of breast cancer. Here we show for the first time that compared with wild type mice, Tyk2 -/- mice show increased tumor growth rate as well as metastatic disease and splenomegaly when inoculated with 4T1 breast cancer cells. Such increased tumorigenicity was associated with a significant decrease of IFNg production in 4T1 tumor-bearing Tyk2 deficient mice T cells compared with wild type (WT) mice. We demonstrated that NK cells or CD8+ T cells control tumor growth in both Tyk2-/- and WT mice, but neither Tyk2-/- NK cells alone nor Tyk2-/- CD8+ T cells alone do not contribute to enhanced tumor growth and metastatic disease of Tyk2-/- mice. Tumor-bearing Tyk2-/- mice have increased level of myeloid-derived suppression cells than tumor-bearing mice. Tyk2-/- MDSCs have a slight increase in suppression of T cell proliferation. Since elevated phosphorylation of Stat3 has been seen in human and murine breast cancer, and expression of Stat3 in the mitochondria (mitoStat3) appears to have important affects on cell growth, we studied the ability of Stat3 targeted to the mitochondria (MLS Stat3) to influence growth and metastasis of 4T1 cells. We show that a serine mutant of Stat3 expressed in the mitochondria (Stat3 S727A) inhibits the ability of 4T1 tumor cells to grow and metastasize. In contrast, a serine to aspartic acid mutant of Stat3 (S727D) enhances tumorigenesis. We found that expression of mitochondrial-targeted Stat3 does not affect cell growth rate in cell culture under normal conditions, however in low glucose, the serine to alanine mutant shows reduced growth rate and ability to invade. Moreover, we found that expression of mitochondrial-targeted Stat3 protects cells from hypoxia. Our data indicate that serine phosphorylation of mitochondrial-localized Stat3 is required for cell transformation. In summary, our studies provided new insights into the role of Stat3 in breast cancer and suggest new therapeutic targets for the treatment of this disease.
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Saharinen, Pipsa. "Signaling through the Jak-Stat pathway : regulation of tyrosine kinase activity." Helsinki : University of Helsinki, 2002. http://ethesis.helsinki.fi/julkaisut/mat/bioti/vk/saharinen/.
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Talerico, Cassandra. "Temporal Activation of the JAK-STAT Pathway in Relation to Cardiac Gene Expression in a Mouse Model of Cardiac Dysfunction." Cleveland State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=csu1197055735.
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Strickland, Janae. "The Role of STAT and the Jak/STAT Pathway In Mediating the Effects of Interleukin-6 on StAR Expression." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1781.pdf.
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Murtfeldt, Eric Robert. "Consequences of ectopic JAK/STAT pathway activation in the Drosophila male germline." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p1457319.
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Thesis (M.S.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed November 5, 2008). Available via ProQuest Digital Dissertations. Includes bibliographical references (p. 51).
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Lukashova, Viktoria. "Involvement of the Jak/STAT pathway in platelet-activating factor receptor signaling." Thèse, Sherbrooke : Université de Sherbrooke, 2003. http://savoirs.usherbrooke.ca/handle/11143/4173.
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Benham, Rebecca Sturtevant. "BDNF and JAK/STAT: partners in seizure-induced GABA-A receptor downregulation." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12281.
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Thesis (Ph.D.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.Brain derived neurotrophic factor (BDNF) plays an important role in development, differentiation, and survival of neurons. However, alterations in BDNF expression also occur in a number of neurological disorders including epilepsy, and its comorbidities (cognitive impairment and depression). Many laboratories have identified BDNF as a key component in epileptogenesis, linking ineffective inhibitory neurotransmission to seizure susceptibility in temporal lobe epilepsy (TLE). γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system, and its type A receptor (GABAARs), are believed to play a significant role in epilepsy development, as altered GABAAR subunit composition may contribute to epilepsy susceptibility in TLE. The Russek laboratory, in collaboration with Dr. Brooks-Kayal, discovered that BDNF is a key regulator of GABAAR composition, as it increases α4-containing GABAARs and decreases α1-containing GABAARs, the major synaptic GABAAR in neurons. This thesis provides further evidence that BDNF inhibits αl synthesis via activation of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling that promotes expression of inducible cAMP early repressor (ICER), whose target is the αl-subunit gene (Gabral). The overarching hypothesis is that prolonged seizures increase levels of BDNF, which alter brain inhibition via activation of the JAK/STAT pathway. Over time these changes in inhibition contribute to epileptogenesis, or the development of epilepsy. How BDNF-signaling activates the JAK/STAT pathway to contribute to decreased Cabral expression was not known. Studies of this thesis suggest that a novel BDNF receptor/signaling pathway regulates such changes. BDNF binds two receptors, tropomysin related kinase B (TrkB) and p75 neurotrophin receptor (NTR). Alterations in neurotrophin receptor expression are observed in animal models of epilepsy. Thesis results show that exposure to recombinant BDNF autologously regulates neurotrophin receptor expression in primary cortical neurons in a manner similar to what is observed in models of epilepsy, reducing levels of TrkB and increasing p7SNTR. These findings suggest a distinct relationship between BDNF and the expression of its receptors. Taken together, the working hypothesis is that BDNF regulates Cabral expression through a selective activation of neurotrophin receptors that is coupled directly to the JAK/STAT pathway. This pathway controls ICER synthesis to directly repress Cabral transcription.
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Ruez, Richard. "Mécanotransduction par les cavéoles : rôle dans l'activation de stat3 par l'interferon alpha." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112232.
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Hypothèse : Notre équipe étudie le rôle, mal connu, du trafic membranaire dans le contrôle de l’activation de la voie de signalisation JAK/STAT par les interférons (IFN), une voie clé du contrôle des processus cancéreux. La liaison de l’IFN-a à son récepteur IFNAR active les kinases JAK1 et TYK2 puis des transducteurs de signal comme STAT1, antiprolifératif, ou STAT3, qui a un pouvoir oncogénique. Le laboratoire a démontré récemment que le trafic membranaire d’IFNAR détermine la spécificité du signal des différents IFNs.L’objet de cette thèse est l’étude du rôle des cavéoles dans ce contrôle. Les cavéoles sont des invaginations membranaires enrichies en cholestérol et glycosphingolipides, formées par l’oligomérisation de la cavéoline1 (Cav1). Les cavéoles ou le gène CAV1 ont souvent été associés à la progression tumorale, notamment des cellules mammaires, mais ce rôle reste énigmatique et controversé. Le fait que IFNAR ait été détecté par biochimie dans des fractions de membrane enrichies en cholestérol et positives pour la cavéoline-1 chez la souris et le fait que l’expression du gène CAV1 ait été corrélée à l’action antitumorale de l’IFNa nous ont conduit à étudier le rôle des cavéoles dans l’action antitumorale des IFNs.Résultats: Le rôle putatif des cavéoles sur le contrôle de la voie JAK/STAT a été étudié dans des cellules murines MLEC n’exprimant pas Cav1 et dans des lignées humaines par interférence ARN contre Cav1. Nous avons pu démontrer que la présence de Cav1 régule de manière opposée deux étapes de la voie de signalisation de STAT3 activée par l’IFN-a. Par contre, ni l’activation de STAT1 par l’IFN-a ni celle de STAT3 par les autres IFNs ne nécessitent Cav1. Parallèlement, le laboratoire a montré que les cavéoles jouent un rôle capital dans la réponse cellulaire aux stress mécaniques en se dépliant lors d’un étirement membranaire, ce qui amortit la tension membranaire. Nous montrons qu’un tel stress mécanique par étirement module spécifiquement la signalisation de STAT3 par l’IFN-a d’une manière dépendante de Cav1 dans les cellules MLEC, suggérant pour la première fois un rôle de STAT3 et de l’IFN-a dans la mécanotransduction dépendante des cavéoles. Ce résultat permet aussi de relier les contraintes mécaniques présentes dans la masse tumorale et leur effet sur la progression tumorale. Perspectives : Les IFNs et la voie JAK/STAT sont bien caractérisés pour leur action antiproliférative, mais si l’IFN-a est utilisé en thérapeutique oncologique, les mécanismes de l’effet antitumoral sont mal connus. Nos résultats impliquent pour la première fois les cavéoles dans l’activation sélective du proto-oncogène STAT3 par l’IFN-a et proposent STAT3 comme un des nouveaux acteurs de la mécanotransduction par les cavéoles. Elucider les mécanismes moléculaires mis en jeu dans ces deux fonctions inédites des cavéoles devrait permettre d’identifier de nouvelles cibles thérapeutiques dans la progression tumoraleHypothesis: Our team studies the poorly investigated role of membrane trafficking in the control of the activation of the JAK / STAT signaling pathway by interferons (IFN), a key mechanism in the control of tumorigenesis. The binding of the IFN-a to its receptor IFNAR activates the kinases JAK1 and TYK2 and then, signal transducers and activators of transcription including the antiproliferative STAT1 or the oncogenic STAT3. The laboratory demonstrated recently that the trafficking of IFNAR at the plasma membrane determines the signal specificity of the various IFNs.The goal of this thesis was to study the role of caveolae in this control. Caveolae are specialized membrane invaginations enriched in cholesterol and glycosphingolipids, formed by the oligomerization of their main structural protein, caveolin-1 (Cav1). Caveolae or the CAV1 gene have often been associated with tumorigenesis, in particular in mammary cancer cells, but this role remains enigmatic and controversial. The fact that IFNAR was previously found in Cav1-positive lipid microdomains and the fact that the expression of the CAV1 gene had been functionally linked to the antitumoral function of IFN-a led us to investigate the role of caveolae in the antitumoral function of the IFNs.Results: The putative role of caveolae in the control of the JAK / STAT signaling pathway have been studied in murine lung endothelial MLEC cells that do not express Cav1 and in a human lineage by RNA interference against Cav1. We were able to demonstrate that the presence of Cav1 regulates in an opposite manner two stages of the signaling pathway of STAT3 activated by the IFN-a whereas the activation of STAT1 by IFN-a, or STAT3 by the other type I and II IFNs do not require Cav1.At the same time, the laboratory showed that caveolae play a major role in the cellular answer to mechanical stress by flattening during a membrane stretching, thus buffering the membrane tension. We show that mechanical stress by uniaxial cell stretching modulates specifically the signaling pathway of STAT3 activated by the IFN-a in a Cav1-dependant manner in MLEC cells. This result suggests for the first time a role of STAT3 and of IFN-a in caveolae-driven mechanotransduction. This result also allows us to link the mechanical constraints found in the tumoral mass to their effect on tumorigenesis.Prospects:The IFNs and the JAK / STAT signaling pathway protect the cells from tumorigenesis, but although IFN-a is used in oncology, the mechanisms of its antitumoral effect are poorly known. Our results involve for the first time caveolae in the selective activation of the proto-oncogenic STAT3 by the IFN-a and allow us to propose STAT3 and the IFN-a as new actors of the mechanotransduction by caveolae. Clarifying the molecular mechanisms involved in these two new functions of caveolae should allow us to identify new therapeutic targets in tumorigenesis
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Rollin, Simon. "Modulation de la signalisation du récepteur du facteur d'activation plaquettaire par SOCS3." Thèse, Université de Sherbrooke, 2009. http://savoirs.usherbrooke.ca/handle/11143/4296.
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Le facteur d'activation plaquettaire (PAF) est un puissant médiateur pro-inflammatoire impliqué dans des processus physiologiques et pathologiques.Le PAF exerce ses effets suite à la liaison à son récepteur, le récepteur du PAF (PAFR), qui est un récepteur à sept domaines transmembranaires et couplé aux protéines G (RCPG). La signalisation du PAFR est en partie médiée par les protéines G et implique principalement des sous-unités G[indice inférieur [alpha]i] et G[indice inférieur [alpha]q] dans plusieurs types cellulaires.Le PAFR peut également activer des effecteurs variés : des canaux ioniques, des phospholipases (PLA[indice inférieur 2], PLC, PLD), ainsi que plusieurs kinases (PKC, PI3K et MAPK). Nous avons récemment démontré que le PAFR peut activer de façon indépendante des protéines G la voie des Janus kinase (JAK) et des Signal Transducers and Activators of Transcription (STAT). JAK2, TYK2 et STAT1, 2, 3 et 5 sont ainsi activés dans la lignée cellulaire myéloïde humaine MonoMac1. Les SOCS sont une famille de protéines qui régulent négativement la signalisation des cytokines et qui ont récemment été démontrés comme impliqués dans la signalisation de certains RCPG dont le CXCR4 (récepteur de chimiokine 4 de la famille des C-X-C) et l'AT1 (récepteur de l'angiotensine II). Une stimulation au PAF induit de manière transcriptionnelle l'accumulation de l'ARNm de la protéine suppressors of cytokine signalling 3 (SOCS3) dans les monocytes humains et la lignée cellulaire MonoMac1, mais ne l'induit pas dans les cellules endothéliales de veines de cordons ombilicaux humain (HUVEC). En plus d'une augmentation de l'ARNm de SOCS3, une augmentation de la protéine SOCS3 est également observée suivant une stimulation au PAF. Premièrement, nous voulions déterminer l'importance de SOCS3 dans la signalisation du PAFR à l'aide de différentes lignées cellulaires (HEK293, COS7, MonoMac1) et diverses techniques de biologie cellulaire. Ensuite, nous désirions évaluer l'impact des différents domaines de SOCS3 dans ces fonctions par des approches de biologie moléculaire. Finalement, nous avons évalué le/s rôle/s de SOCS3 sur différents aspects fonctionnels pro-inflammatoires du PAF (Voies signalisation, adhésion cellulaires, etc.). Nous démontrons dans la présente thèse que SOCS3 module la signalisation du PAFR en plus de présenter certains aspects moléculaires entourant la relation entre le PAFR, TYK2 et SOCS3. Les présents travaux démontrent que SOCS3 peut être recruté de façon transitoire à la seconde boucle intracellulaire et la queue cytoplasmique du PAFR. Son domaine kinase inhibitory region (KIR) semble être requis pour le recrutement induit au PAFR, alors que son domaine SOCS box semble être impliqué dans le recrutement basal. Suivant une stimulation au PAF, SOCS3 est phosphorylé sur un/des résidus tyrosine. Cette modification est sous le contrôle essentiel de TYK2, alors que son mutant K930I (kinase inactive) ne le fait pas. SOCS3 joue un rôle très important dans la modulation des voies de signalisation du PAFR ainsi que sur certains effets biologiques de celui-ci. Ces actions se révèlent être également très spécifiques : SOCS3 ne module pas la voie de G[indice inférieur [alpha]q] (IP3 ), mais module la migration et également l'adhésion cellulaire induite par le PAF. SOCS3 ne module pas la phosphorylation des STAT 1, 3 et 5 induite par le PAF, mais module négativement la voie de TYK2 (activation du promoteur du PAFR) et la phosphorylation des STAT 1, 3 et 5 induite par l'OSM. SOCS3 ne module pas la voie des JNK MAPK, prolonge la voie des ERK MAPK et module négativement l'activation précoce de la voie de p38 MAPK. Enfin, SOCS3 joue un rôle de modulation négative dans la transcription induite par le PAF des promoteurs du PAFR, de l'IL-6 et de l'IL-8. En conclusion, cette thèse propose de nouveaux mécanismes par lesquels SOCS3 module certains aspects de la signalisation et effets biologiques du PAF et de son PAFR. Comme le PAF est impliqué dans plusieurs phénomènes à caractères inflammatoires, le travail présenté ici a porté son attention sur plusieurs aspects pro-inflammatoires du PAF plutôt que sur une pathologie en particulier, ce qui permettra de mieux comprendre divers aspects liant le PAFR, la kinase TYK2 et SOCS3.
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Secardin, Lise. "Modélisation des néoplasmes myéloprolifératifs grâce aux cellules souches induites à la pluripotence (IPSC)." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC313/document.
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Les néoplasmes myéloprolifératifs (NMP) sont hémopathies malignes aboutissant à la surproduction d'une ou plusieurs lignées myéloïdes. Elles sont dues à l'acquisition de mutations sur l'axe de signalisation MPL/JAK2 incluant des mutations de JAK2V617F, de MPL et plus récemment de la calréticuline (CALR), dont les deux principales sont CALRdel52 et CALRins5. Ces mutations de signalisations peuvent être accompagnées de mutations de l'épigénétique, les plus importantes étant des mutations dans TET2. Le but de cette thèse était d'étudier le rôle des mutations de TET2 et de la calrdel52 dans les NMP grâce à une technologie de cellules souches induites à la pluripotence (IPSC). Dans la première partie j'ai pu démontrer que TET2 joue un rôle dans le processus de reprogrammation, vraisemblablement de manière indépendante de son activité catalytique. Dans la seconde partie, j'ai démontré que CALRdel52 joue un rôle dans les MPN en provoquant une hypersensibilité et une pousse indépendante de la TPO des progéniteurs mégakaryocytaires ainsi qu'une hyperprolifération des mégacaryocytes, liées à l'activation constitutive de stat3 et de ERK. J'ai également démontré une pousse indépendante du GCSF des granulocytes. Ce travail a donc permis de mettre en lumière le rôle du facteur épigénétique TET2 dans le processus de reprogrammation ainsi que le rôle de CALRdel52 dans les MPN dans un contexte d'expression endogèneMyeloproliferative neoplasms (NMP) are hematological malignancies that lead to an ovrproduction of one or more myeloid lineages. They are driving by mutations in MPLl/jak2 signaling pathway, mainly JAK2V617F, MPL, and more recently calreticulin (CARL), with two main mutations being calrdel52 and calrins5. These signaling mutations are sometimes associated with epigenetic mutations, the major one being in tet2. The objective of my thesis was to study the role of TET2 and CALRdel52 in MPN thanks to an induced pluripotent stem cells (IPSC) model. In the first part i demonstrated the role of TET2 in reprogramming process, probably independently of the catalytic domain. In the second part i demonstrated that CALRdel52 induced a TPO hypersensitivity and a TPO indenpendant growth of the megakaryocytic progenitors as well as a hyperproliferation of the megakaryocytes. This phenotype is associated with a constitutive activation of stat3 and ERK. A G-CSF independent growth of the granulocyte was also demonstrated. In conclusion this work underline the role of an epegenetic factor, TET2, in the reprogramming process and demonstrate the role of CALRdel52in MPN with an endogenous expression model
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Gomes, Guilherme Wataru. "Expressão gênica dos transportadores de membrana ABCB1,ABCG2, SLC22A1 e SLCO1A2 em linhagens celulares tratadas com inibidor comercial da via JAK-STAT." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-16032016-095918/.
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INTRODUÇÃO: A desregulação da via de sinalização JAK-STAT é uma característica marcante das neoplasias mieloproliferativas (NMPs), doenças clonais da célula tronco hematopoética, dentre as quais encontra-se a mielofibrose (MF). Diversos inibidores de JAK foram desenvolvidos para o tratamento da MF e encontram-se em diferentes fases de desenvolvimento clínico. Devido ao seu desenvolvimento recente, pouco se sabe a respeito do papel de transportadores de membrana na farmacocinética desses compostos. Essas proteínas realizam o influxo e efluxo celular de substratos endógenos e xenobióticos, e alterações na expressão desses transportadores podem influenciar a resposta a esses fármacos. OBJETIVO: Avaliar o efeito de um inibidor comercial da via JAK-STAT na expressão gênica dos transportadores de membrana ABCB1, ABCG2, SLC22A1 e SLCO1A2 em células HepG2, Caco-2 e HEL92.1.7. MÉTODOS: Linhagens de carcinoma hepatocelular (HepG2), adenocarcinoma colorretal (Caco-2) e eritroleucemia humana homozigotas para JAK2V617F (HEL92.1.7) foram cultivadas e tratadas o inibidor comercial da via JAK-STAT JAK Inhibitor I. Para determinar a concentração ideal para o tratamento com o inibidor, as células foram tratadas com diversas concentrações do inibidor de JAK por 24 horas e foram feitos testes de viabilidade celular e fragmentação do DNA. Com as condições de tratamento padronizadas, foi extraído o RNA total das células e sintetizado o cDNA, para análise das expressões de RNAm dos genes ABCB1, ABCG2, SLC22A1 e SLCO1A2 por PCR em tempo real. Foi também avaliada a expressão dos transportadores de efluxo ABCB1 e ABCG2 por citometria de fluxo, utilizando anticorpos primários direcionados a essas proteínas. RESULTADOS: Nas células HepG2, foi observado um aumento da expressão de RNAm de ABCB1 nas células tratadas com 4,00 µM do inibidor de JAK, quando comparado com o controle (células incubadas apenas com o veículo) (P=0,041). Não foi observada alteração da expressão de RNAm de ABCG2 e SLC22A1 com o tratamento com o inibidor de JAK nessa linhagem (P>0,05); a expressão de RNAm de SLCO1A2 não foi detectada nessa linhagem. Nas células Caco-2, a expressão de ABCB1, ABCG2, SLC22A1 e SLCO1A2 não se alterou com o tratamento com o inibidor de JAK nas concentrações utilizadas (0,25 µM a 1,00 µM) por 24 horas (P>0,05). Para as células HEL92.1.7, não foi observada diferença na expressão de RNAm de ABCB1, ABCG2 e SLC22A1 com o tratamento com 1,00 µM do inibidor de JAK por 24 horas em comparação ao controle (P>0,05); nessa linhagem, a expressão de RNAm de SLCO1A2 não foi detectada. A expressão proteica dos transportadores ABCB1 e ABCG2 não sofreu alteração com o tratamento com o inibidor de JAK nas condições utilizadas nas três linhagens celulares estudadas (P>0,05). CONCLUSÕES: Apenas as células HepG2 apresentaram um aumento da expressão de RNAm do transportador de efluxo ABCB1 em concentrações elevadas do inibidor de JAK, sugerindo que os inibidores de JAK podem modular a expressão do gene desse transportador no fígado. O tratamento com o inibidor da via JAK-STAT não foi associado com alterações na expressão proteica de ABCB1 e ABCG2 em todas as células estudadas.BACKGROUND: JAK-STAT pathway signaling disregulation is a hallmark of myeloproliferative neoplasms (MPN), hematopoietic stem cell clonal diseases, among which is myelofibrosis (MF). Several JAK inhibitors have been developed for MF treatment and are found in different stages of clinical development. Because the recent development of these compounds, the role of drug transporters in their pharmacokinetics is poorly understood. These proteins perform celular influx and effux of endogenous substrates and xenobiotics, and changes in the expression of these drugs transporters may affect the response to these drugs. AIM: To evaluate the effect of a JAK-STAT pathway commercial inhibitor in gene expression of drug transporters ABCB1, ABCG2, SLC22A1 and SLCO1A2 in HepG2, Caco-2 and HEL92.1.7 cells. METHODS: Hepatocellular carcinoma cell line HepG2, colorectal adenocarcinoma cell line Caco-2 and human erythroleukemia homozygous JAK2V617F cell line HEL92.1.7 were grown and treated with the JAK-STAT pathway inhibitor JAK Inhibitor I. In order to determine the optimal concentration for treatment with the inhibitor, cells were treated with several concentrations of JAK inhibitor by 24 hours, and cell viability and DNA fragmentation tests were performed. Once the treatment conditions were standardized, total RNA were obtained from the cells, and cDNA was synthesized in order to evaluate the mRNA expression of ABCB1, ABCG2, SLC22A1 and SLCO1A2 genes, performed by real time PCR. We also evaluate the expression of drug efflux transporters ABCB1 and ABCG2 by flow cytometry, using primary antibodies directed to these proteins. RESULTS: In HepG2 cells, it was observed an increase in ABCB1 mRNA expression in cells treated with 4,00 µM of JAK inhibitor, when compared with controls (cells exposed only to the vehicle) (P=0.041). There was no change in ABCB2 and SLC22A1 mRNA expression with the treatment with JAK inhibitor in this cell line (P>0.05); SLCO1A2 mRNA was not detected in this cell line. In Caco-2 cells, ABCB1, ABCG2, SLC22A1 and SLCO1A2 mRNA expression did not change with treatment with the JAK inhibitor at the concentrations used (0.25 µM to 1.00 µM) by 24 hours (P>0.05). In HEL92.1.7 cells, it was not observed differences in ABCB1, ABCG2 and SLC22A1 mRNA expression with the treatment with 1 µM of JAK inhibitor by 24 hours when compared with controls (P>0.05); in this cell line, SLCO1A2 mRNA was not detected. Protein expression of ABCB1 and ABCG2 drug transporters has not changed with treatment with the JAK inhibitor under the conditions used in the three cell lines studied. CONCLUSIONS: Only HepG2 cells presented an increase in mRNA expression of drug efflux transporter ABCB1 in presence of high levels of JAK inhibitor, suggesting that JAK inhibitors could modulate this transporter gene expression in liver. Treatment with JAK-STAT pathway inhibitor was not associated with changes in ABCB1 and ABCG2 protein expression in all cell lines studied.
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Shen, Ying. "The JAK/STAT pathway in Drosophila hematopoiesis: function and regulatory mechanisms." Ohio : Ohio University, 2007. http://www.ohiolink.edu/etd/view.cgi?ohiou1194628059.
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Matlock, Jennifer Renee. "THE JAK-STAT PATHWAY IS REQUIRED FOR MULTIPLE EARLY EVENTS IN DROSOPHILA OOGENESIS." UKnowledge, 2002. http://uknowledge.uky.edu/gradschool_theses/205.
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The Janus kinase (JAK) pathway is an integral part of signaling through a variety of ligands and receptors in mammals. The extensive reutilization and pleiotropy of this pathway in vertebrate development is conserved in other animals as well. In Drosophila melanogaster, JAK signaling is involved in embryonic pattern formation, sex determination, larval blood cell development, wing venation, planar polarity in the eye, and formation of other adult structures. Here we describe several roles for JAK signaling in Drosophila oogenesis. The gene for a JAK pathway ligand, unpaired, is expressed specifically in the polar follicle cells, two pairs of somatic cells at the anterior and posterior poles of the developing egg chamber. A primary defect of chambers with reduced JAK activity is fusion of successive chambers. These chambers exhibit an expansion of the polar cell population and concomitant loss of interfollicular stalk cells. Mosaic analysis of both JAK pathway transducers, hopscotch and stat92E, reveals that JAK signaling is specifically required in the somatic follicle cells. Another role of JAK signaling is in oocyte localization. In chambers mosaic for loss of hop activity, oocyte mislocalization results. Proper localization occurs only when the posterior follicle cells are wild type for hop.
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Younis, Usir, and Usir Younis. "Inhalational Delivery of a JAK3 Inhibitor for the Novel Treatment of Asthma and the Investigation of Pharmaceutical Salts in HFA Propellant Systems." Diss., The University of Arizona, 2018. http://hdl.handle.net/10150/626756.
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Asthma is a significant lung disease involving chronic inflammation and remodeling of the airways, resulting in reduced quality of life for those who suffer from the condition. Current therapeutic guidelines suggest the use of inhaled corticosteroids for long-term anti-inflammatory relief to manage moderate to severe chronic asthma; however, inhaled corticosteroids fail to provide prophylactic or reversal treatment of damaged airways incurred by chronic asthma as well as exhibiting adverse side effects (skeletal complications, diabetes, and weight gain).Therefore, there is a need for a new type of drug therapy to address these gaps in the treatment of chronic asthma. There is growing interest aimed towards the inhibition of the Janus Kinase and Signal Transducer and Activator of Transcription (JAK-STAT) pathway for the treatment of asthma. Despite the promising opportunity to investigate this new pathway towards this clinical application, no published work is available using an established and characterized JAK 1/3 inhibitor for the treatment of chronic asthma delivered via inhalation.
This work investigated tofacitinib citrate, a selective JAK 3 inhibitor, and its potential to be delivered locally to the lungs for the treatment of chronic asthma. Several preformulation studies were conducted to determine the basic physical and chemical properties of the compound and its free base, tofacitinib, for proper inhalational formulation development. The drug was delivered to BALB/c mice challenged with house dust mite (HDM) allergen via nebulization utilizing a nose-only chamber. After a three week dosing schedule, mice treated with tofacitinib citrate exhibited an increase in monocyte cell numbers with a simultaneous decrease in eosinophil cell count, gathered from BAL fluid. Further, the experimental groups treated with tofacitinib citrate had a decrease in total protein concentrations in comparison to the experimental groups that were only challenged with HDM or were both exposed to HDM and vehicle. These findings demonstrated that the proper formulation was developed for nebulized delivery of tofacitinib citrate, and that the compound was capable of reducing total protein concentrations and eosinophil cell recruitment, both recognized as biomarkers for an asthmatic response. Although significant work is still needed to be done, these data hold promise for the potential of a locally delivered JAK 3 inhibitor as a treatment for chronic asthma.
Further, the solubility of tofacitinib citrate and five other pharmaceutical salts were determined in HFA 134a, HFA 227, and DFP with varying cosolvent content (0-20% v/v ethanol). The experimental solubilities of the free acid and base compounds were larger than the solubilities of their respective salts in all three systems for tofacitinib, albuterol, and salicylic acid. Warfarin, phenytoin, and ciprofloxacin had similar solubilities with their respective salt forms. Solubilities also increased with increasing cosolvent concentration for all compounds investigated. The model propellant, DFP, provided a slightly stronger correlation of solubility values with HFA 134a in comparison to HFA 227. The observed solubility values were also compared to calculated values obtained from the ideal solubility model, where it was determined that the observed solubility was indeed also dependent on its surrounding solvent interactions and not solely on its ideal solubility (melting point). While some physical changes were observed for the pharmaceutical salts in HFA 134a and 227, more quantitative studies are needed for a larger database of compounds to better understand the factors that contribute to the solubility of pharmaceutical salts (and their correlation to DFP), in HFA-based systems. This information could potentially contribute to a predictive model, saving time and money during the process of pMDI formulation development.
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Mazard, Pasquier Virginie. "Le système IL-2/Récepteur de l'IL-2 : les dysfonctionnements de la voie de signalisation Jak/Stat dans le cadre de l'infection par le VIH." Paris 7, 2004. http://www.theses.fr/2004PA077128.
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de, Carvalho Leandro Danilo. "Análise da imunidade de Aedes Aegypti (Diptera: Culicidae) ao vírus dengue em populações de campo com competência vetorial diferenciada." Universidade Federal de Pernambuco, 2011. https://repositorio.ufpe.br/handle/123456789/1020.
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Previous issue date: 2011Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco
Um dos determinantes envolvidos no complexo ciclo de transmissão da dengue é o nível de susceptibilidade do Aedes aegypti ao vírus dengue (DENV), ou seja, a competência vetorial, que varia entre populações de mosquitos. Identificar moléculas envolvidas na interação mosquito-vírus pode auxiliar no conhecimento dos mecanismos envolvidos na competência vetorial, até então pouco elucidados. Estudos recentes mostraram a participação de certos mecanismos na interação mosquito-DENV, porém, pouco se sabe do real papel destes na modulação da competência vetorial em mosquitos de campo ou até da relação entre eles. Mediante isso, objetivamos analisar a expressão de três moléculas representantes de diferentes mecanismos de defesa antiviral no Ae. aegypti, em resposta à infecção com vírus dengue sorotipo 2 (DENV-2), sendo elas REL1, HOP e Dicer-2, em populações de campo e de laboratório do mosquito. Para isso, as diferentes linhagens foram artificialmente infectadas com DENV-2, e tecidos variados foram coletados em diversos momentos após infecção. Tanto a quantificação viral quanto a expressão das moléculas selecionadas nas amostras foram realizadas por PCR em tempo real quantitativo (qRT-PCR). Os resultados mostraram que tanto o padrão de infecção viral quanto a expressão das moléculas variaram entre as populações de A. aegypti nos diferentes momentos após infecção com DENV-2. Os resultados aqui obtidos poderão ser bastante relevantes na pesquisa da interação vetor-vírus e poderão auxiliar no desenvolvimento de novas estratégias de controle da dengue, como na pesquisa com mosquitos transgênicos
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Paliouras, Grigorios Nikiforos. "Effect of ethanol on the Jak-Stat pathway : is this an NMDA mediated event?" Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79062.
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Alcohol affects many neurochemical processes, causing long-lasting changes in both the adult and developing brain. The Jak-Stat transcriptional activation pathway plays a role in the control of neuronal proliferation, survival and differentiation, but the effects of ethanol on the system have not been fully elucidated. The goal of this project was to define the effects of acute and subchronic ethanol exposure on the expression of proteins in the Jak-Stat pathway, using cultured NG108-15 cells, and in addition, to test the hypothesis that these effects are mediated through the NMDA receptor. I found that ethanol dose-dependently decreased Jak2 and Stat3 following subchronic exposure of NG108-15 in culture. Acute ethanol exposure caused a dose-dependent decrease in Stat3 protein levels. Incubation with MK-801 or ketamine, two noncompetitive NMDA receptor antagonists, or the receptor agonist NMDA, produced dose-dependent decreases in Stat3 protein as well.
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Yockell-Lelièvre, Julien. "Étude de la régulation transcriptionnelle de ICAM-1 : implication de la voie JAK/STAT." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27403/27403.pdf.
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Etter, Jonathan Parker. "Development of Inhibitors in the IL-6/GP130/JAK/STAT Pathway as Therapeutic Agents." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376525461.
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Kördel, Kristin [Verfasser]. "Targeting JAK/STAT signalling for sensitization of colorectal cancer cells to chemoradiotherapy / Kristin Kördel." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://d-nb.info/123712896X/34.
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Nascimento, Augusto Santana [UNESP]. "Mecanismos moleculares envolvidos com a resistência química de células tumorais de mama." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/148592.
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Embora algum progresso tenha sido alcançado nos últimos anos, ainda são necessários estudos capazes de desvendar os mecanismos moleculares envolvidos com o fenótipo de resistência a múltiplas drogas (MDR) em células tumorais. Com esta finalidade, estabelecemos o perfil quinômico (através do microarranjo de peptídeos, PepChip) das linhagens MCF7 e MCF7Res, fenótipo parental e resistente respectivamente, de células de câncer de mama. Os resultados obtidos pelo microarranjo de peptídeos e posteriormente, validados por western blotting, apontaram o envolvimento da via de sinalização Jak-Stat e isoformas de PKC no processo de resistência das células de câncer de mama. Além disso, mostramos envolvimento de p42/44-mapk, Ras e um aumento na expressão de MMP-9. Estes resultados mostram o potencial agressivo destas células resistentes, visto que estas vias estão envolvidas em mecanismos responsáveis pela proliferação e invasão celular. Como as proteínas Jak1 e Jak2 mostraram-se envolvidas, decidimos avaliar níveis de fosforilação de Stats 1, 2, 3, 5 e 6 e mostramos que todas estavam up-fosforiladas nas células resistentes. Baseado nestes resultados, decidimos avaliar através de um ensaio funcional, o papel de Jak2 no fenótipo resistente e, desta forma, avaliamos a viabilidade das células MCF7Res em pré-tratamento com 2 concentrações subtóxicas do inibidor de Jak2 (5µM e 10µM) e nossos resultados claramente mostraram que, inibindo Jak2, as células MCF7Res ficam mais sensíveis a daunorrubicina, aumentando a taxa de morte celular frente à resposta ao quimioterápico. Baseado nos resultados obtidos pelo fosfoproteoma concluímos que o fenótipo MDR envolve metabolismo específico em células tumorais de mama, onde isoformas de PKCs e sinalização Jak-Stat exercem função de destaque. Assim, estes dados apontam o potencial uso de inibidores de Jak2 como estratégia para o tratamento de pacientes não responsivos a terapias convencionais.
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Fagan, Erin A. "Identification of the presence and activity of the JAK-STAT pathway in canine solid tumors." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/100859.
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Background: The JAK-STAT pathway is a cellular signaling pathway, which acts normally in humans and animals in the control of multiple important functions. Dysregulation of this pathway has been identified in human cancers, as well as a limited number of veterinary cancers.
Objectives: The aims of this study were to identify the presence and tentative activity of components of the JAK-STAT pathway in selected canine tumors.
Methods: Formalin-fixed, paraffin-embedded samples from mast cell tumors (MCT), hemangiosarcomas (HSA), thyroid carcinomas, and apocrine gland anal sac adenocarcinomas (AGASACA) were obtained from the Diagnostic Histopathology Laboratory at the Virginia Maryland College of Veterinary Medicine. Immunohistochemistry was performed to evaluate protein levels of JAK1, phospho-JAK1, JAK2, phospho-JAK2, STAT3, and phospho-STAT3. Signalment, treatment information, and survival information was obtained from the medical record for each case.
Results: Tumor samples were scored for percent positive neoplastic cells. Positive staining was seen for all antibodies in all tumor types, with expression of JAK1, STAT3, and pSTAT3 being highest overall for all tumor types. Significant associations were seen between JAK1 and survival time in MCT (p = 0.03), pJAK1 and survival time in HSA (p = 0.009) and MCT (p = 0.04), and pSTAT3 and metastasis in MCT (p = 0.0008).
Conclusions: The finding of positive staining for the components of the JAK-STAT pathway in the tumor samples evaluated indicates presence and tentative activity of this pathway in the studied cancers. Further study of JAK1, pJAK1, and pSTAT3 should be pursued to evaluate their potential as therapeutic targets.MS
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Silver, Debra L. "A novel role for JAK/STAT signaling in cell migration during development and in cancer." Available to US Hopkins community, 2003. http://wwwlib.umi.com/dissertations/dlnow/308076.
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Recasens, Álvarez Carles. "Control of growth and pattering : a novel rol of JAK/STAT in regulating morphogen production and signalling = Control del crecimiento y patrón : un nuevo rol de JAK/STAT regulando la producción y señalización de morfógenos." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/402782.
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During my thesis I studied the developmental roles of the JAK/STAT pathway in the wing imaginal disc and we show that it controls organ size and fate specification by regulating morphogen production and activity. We show three distinguishable biological functions of JAK/STAT depending on the territory and developmental stage. Briefly, JAK/STAT is required in Drosophila limb development to facilitate the activities of Wingless, Hedgehog and the Dpp morphogens in exerting their fate- and growth-promoting functions. Early in development, JAK/STAT is required to guarantee Wg-mediated appendage specification by repressing EGFR target gene expression and thus restricts the notum fate to the most proximal territories of the wing primordium. Later in development, once the wing has been specified, JAK/STAT regulates organ size by ensuring the stable and localized expression of the Dpp organizer at the center of the wing primordium. This function relies on an autonomous and compartment-specific requirement of JAK/STAT in maintaining the size of the posterior territory. We show that JAK/STAT promotes the cycling and survival of P cells and identified diap1 and CycA as the two critical genes regulated by JAK/STAT and contributing to the growth of the Hh expressing cell population. The specific requirement of the P compartment for JAK/STAT serves to counteract the negative effect of Engrailed on cell cycling and survival. Thus, we identified a mechanism by which pro-survival cues and mitotic cyclins ensure the maintenance of a stable pool of morphogen-producing cells. Finally, we also show that JAK/STAT and its growth-promoting activity in the hinge region function as a topological barrier that isolates the body wall and appendage sources of Dpp to delimit its organizing activity to the developing appendage.Durante mi tesis he estudiado el papel de la vía de JAK/STAT en el desarrollo del ala de Drosophila. Nuestros resultados indican que JAK/STAT tiene una función temprana en la subdivisión ala-notum, reprimiendo la via de EGFR para delimitar la región que adquirirá destino de tórax y facilitando así la especificación del ala por Wingless. Además de esta función temprana, JAK/STAT es necesario para contrarrestar el efecto negativo de Engrailed sobre la supervivencia y proliferación de las células productoras del morfógeno Hh en el compartimento posterior. La ausencia de JAK/STAT en estas células causa una reducción del tamaño de este compartimento y eventualmente su pérdida total. Debido a la reducción en el número de células productoras de Hh, la expresión del morfógeno Dpp también se ve afectada, dando lugar a un defecto de crecimiento aún mayor. Así, a través de una función específica en el compartimento posterior, JAK/STAT regula el crecimiento general del ala promoviendo la expresión estable y localizada del morfógeno Dpp. Finalmente, también hemos observado que el crecimiento del hinge (la estructura que une el ala y el tórax en el adulto) mediado por JAK/STAT contribuye a aislar la capacidad organizadora de Dpp únicamente en el territorio de ala