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THE JAK/STAT PATHWAY IS REUTILIZED IN <em>DROSOPHILA</em> SPERMATOGENESISTang, Lingfeng 01 January 2014 (has links)
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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THE FUNCTION OF Socs GENES IN DROSOPHILA DEVELOPMENT AND SIGNALING PATHWAYSGuo, Qian 01 January 2007 (has links)
The duration and intensity of the JAK/stat signaling must be tightly regulated to prevent excessive transcriptional response and to reset the pathway to receive additional signals. Socs are the largest class of these regulators in mammals. Eight Socs genes have been found in mammals. CIS, and SOCS1-3, the canonical Socs, are transcriptionally activated by and down-regulate the JAK signaling. Socs4-7, the non-canonical Socs, are less studied and their relationship with the JAK/STAT pathway has not been well established. The Drosophila genome encodes three non-canonical Socs homologues, Socs16D, Socs36E, and Socs44A. Expression of Socs36E is controlled by the JAK pathway and misexpression causes phenotypes similar to that from reduction of JAK in both ovary and wing, which may make it functionally more similar to the canonical Socs. Expression of Socs44A is not controlled by the JAK pathway and misexpression causes JAK mutant phenotypes in wing but not in ovary. Imprecise excision mutants of the three Socs genes have been generated by us and have no visible phenotypes. The mutants of Socs36E and Socs44A significantly enhance the tumor formation in hopTum-l mutant, a gain-of-function mutation of the JAK/STAT pathway. The function of Drosophila Socs will be further studied with different strategies.
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En jämförande studie mellan islamiska banker, räntefria banker och andra bankerOurtani, Mahjouba January 2015 (has links)
Syftet med denna studie är att visa och jämföra hur olika banker genererar sina intäkter samt att redogöra för vilka skillnader det finns gällande bankernas syn på vinst. Dessutom kommer studien att undersöka olika faktorer för att jämföra bankernas skillnader med avseende på Affärsmodell. Därtill kommer studien att undersöka på vilket sätt bankerna genererar sin vinst och hur deras syn på vinst ser ut. Studien har genomförts genom en fallstudiemodell med flerfallsdesign där de olika fallen består av olika banker. Studien omfattar kvantitativ data och dess natur är generativ. De data som undersökts i studien består dels av bankernas årsredovisningar. Utöver detta har kontakter tagits med relevanta banker och intervjuer har utförts. Studiens empiriska data har analytiskt granskats mot tidigare forskning som funnits relevant tillsammans med vedertagna teorier. Studiens resultat har påvisat att det finns likheter och skillnader i hur de olika bankerna ser på sina intäkter och på det sätt de gör sin vinst. Alla banker har hög kostnadsandel för sin rörelseverksamhet som uppgår till 292.3% för Nordea, 433.1% för JAK medlemsbank och 703.7% för Kuveyt Türk. För samtliga banker visar studien att löne- och personalkostnader är den främsta anledningen. Islamiska banker gör ingen vinst på ränta men både Nordea och JAK medlemsbank redovisar en vinst på sin ränteverksamhet där kostnadsandelen för Nordea är 47.9% och för JAK medlemsbank 5.8%. Dessutom visade studien att både Kuveyt Türk och Nordea gör vinst på sin provisionsverksamhet. Studien har visat att Kuveyt Türks provisionsintäkter på 93.6% av bankens totala intäkter kommer från PLS-arrangemang som banken anordnar tillsammans med sparare och delar på den genererade vinsten på ett islamiskt acceptabelt sätt. Kooperativa bankers mål är inte att göra vinst men denna studie har påvisat att JAK medlemsbank trots sina kapitalreserver skapar vinst och där 76.8% av intäkterna kommer från ränteverksamhet. Studien har skapat nya frågeställningar som ytterligare kan utveckla forskningsområdet. En fråga som har dykt upp under studien är vilken effekt Riksbankens idag negativa reporänta, som har påverkan på bankernas räntor, får på konventionella bankers möjlighet att attrahera sparare. Kommer dess sparare att välja andra sparformer, som till exempel JAK medlemsbank eller islamiska banker den dag de startar i Sverige?
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Implication physiopathologique de l'adaptateur LNK : mécanismes d'action et perspectives thérapeutiques dans les Néoplasmes Myéloprolifératifs / Physiopathological implication of LNK adaptor : mechanisms of action and therapeutic applications in myeloproliferative neoplasmsJungalee, Anouchka 15 December 2016 (has links)
L’adaptateur LNK est un régulateur négatif des voies de signalisation, dont la voie JAK/STAT,essentielle au développement du système hématopoïétique. Son implication dans les hémopathies chroniques, notamment les Néoplasmes Myéloprolifératifs (NMP), a été mise en évidence par l’analyse de souris invalidées pour cet adaptateur et l’identification de mutations de LNK chez les patients atteints de ces pathologies. Toutefois, le mécanisme permettant la régulation de ses partenaires, dont la kinase JAK2, et l’implication fonctionnelle des mutations de LNK dans les NMP, restent à définir. Ainsi, mon projet de thèse a porté sur l’analyse structurale et fonctionnelle des complexes de signalisation LNK/JAK2 et sur le développement d’une stratégie moléculaire pour l’utilisation thérapeutique de LNK dans les NMP. Nos résultats ont montré pour la première fois, la fonction inhibitrice de la région N-terminale incluant le domaine d’homologie à la Pleckstrine deLNK sur JAK2 normale et de manière plus importante, sur la forme mutée JAK2-V617F, retrouvée chez les patients atteints de NMP. De plus, nos études sur les mutations de LNK localisées dans cette région régulatrice, ont permis de comprendre leur contribution dans le développement de ces hémopathies et de proposer un mécanisme d’inhibition de l’activation de JAK2 par LNK. Nos résultats permettent d’utiliser le ciblage de la région N-terminale de LNK comme stratégie moléculaire inhibant spécifiquement la forme oncogénique JAK2-V617F à l’aide de peptides pénétrants (CPP). A long terme, cette approche pourrait être utilisée comme outil thérapeutique dans le traitement de patients atteints de NMP positifs pour JAK2-V617F. / The LNK adaptor protein is a key negative regulator of signalling pathways, such as JAK/STAT, important in the development of the hematopoietic system. Its implication in chronic blood diseases, such as Myeloproliferative Neoplasms (MPN) has been confirmed by studies on Lnk-deficient mice, as well as the identification of LNK mutations in MPN patients. However, the LNK mechanism of regulation on its partners and the functional implication of LNK mutations in MPN pathogenesis, are still unclear. Therefore, my PhD project covers the structural and functional analysis of theLNK/JAK2 signalling complex and the development of a molecular strategy to use LNK as a therapeutic tool for the treatment of MPN patients. Our study showed, for the first time, the inhibitory function of the N-terminal region and the pleckstrin homology domain of LNK on JAK2 activity, which occurs more importantly on JAK-V617F than JAK2 wild type form. Moreover, our study provided evidence on how LNK mutations located in this LNK region could contribute to these haematological diseases and has allowed us to propose a model for LNK regulatory function on JAK2activity. Furthermore, we developed a cell penetrating peptide-based strategy to deliver this regulatory region of LNK in hematopoietic cells to specifically inhibit JAK2-V617F oncogenic form. The finalaim is to use this region as a therapeutic molecule to treat JAK2-V617F-positive MPN patients.
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Análises de mutações no gene JAK2 em pacientes com diagnóstico clínico de Policitemia Vera atendidos em um único centro da cidade de Juiz de ForaFreitas, Renata Mendes de 21 February 2014 (has links)
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Previous issue date: 2014-02-21 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As Neoplasias Mieloproliferativas são originadas por uma proliferação clonal de um
progenitor hematopoético. Descrita inicialmente em 1951 como “Doenças
Mieloproliferativas” e reavaliada pela Organização Mundial da Saúde em 2011, as
Neoplasias Mieloproliferativas agrupam a Policitemia Vera, Trombocitemia Essencial
e Miefibrose Primária em um subgrupo chamado de BCR-ABL negativo. De acordo
com a revisão dos critérios adotados para o diagnóstico das Neoplasias
Mieloproliferativas a presença da mutação JAK2 V617F é considerada critério de
maior importância para o diagnóstico do subgrupo BCR-ABL negativo representando
um marcador clonal. A Policitemia Vera é principalmente diagnosticada por um
aumento na massa eritrocitária independente de fator estimulante, aumento de
leucócitos no sangue periférico, esplenomegalia e trombocitose. Ocorre, geralmente,
em homens e mulheres com faixa etária de 60 anos, com incidência de 0,7 a
2,6/100.000 habitantes/ano. A mutação V617F no gene JAK2 produz uma proteína
alterada que ativa constitutivamente a via JAK-STAT e outras vias downstream de
modo que, as proteínas de ativação transcricional e transdutoras de sinal (STAT do
inglês Signal Transducerand Activator of Transcription) são fosforiladas
posteriormente impactando na expressão de genes envolvidos na regulação da
apoptose e proteínas regulatórias, além de alterar a taxa de proliferação das células
hematopoéticas. Neste trabalho foram selecionados 26 pacientes com Policitemia
Vera, os quais foram atendidos na cidade de Juiz de Fora, Minas Gerais. Foram
realizadas análises de mutações no gene JAK2 a partir do material genético isolado
do sangue periférico. Os dados clínicos de cada paciente foram relacionados entre si
e correlacionados com os dados moleculares. / Myeloproliferative neoplasms (MPN) are caused by a clonal proliferation of a
hematopoietic progenitor. First described in 1951 as “Myeloproliferative Diseases”
and reevaluated by the World Health Organization in 2011 (WHO, 2011), the
Myeloproliferative Neoplasms gather the Polycythemia Vera, Essential
Thrombocythemia and Primary Mielofibrose in a subgroup called negative BCR-ABL.
According to WHO the revised diagnosis criteria for myeloproliferative neoplasms,
the presence of JAK2 V617F mutation, is considered the most important criterion for
the diagnosis of negative BCR-ABL subgroup representing a clonal marker. The
Polycythemia Vera is primarily diagnosed by an independent stimulating factor in red
cells mass increasing, followed by an increase of leukocytes in peripheral blood,
spleen and thrombocytosis. It usually occurs in men and women of all age groups
with higher incidence in 60-year-old patients ranging from 0.7 to 2.6/ 100.000
hab/year. The V617F mutation in the JAK2 gene produces an altered protein that
activates constitutively the JAK-STAT pathway and other pathways downstream as a
result the protein transcriptional activation and signal transduction (STAT) are
subsequently phosphorylated causing impact in the expression of genes involved in
regulation of apoptosis and regulatory proteins, as well as altering the rate of
proliferation of hematopoietic cells. In this study 26 patients with Polycythemia Vera
were selected in Juiz de Fora, Minas Gerais. The peripheral blood was used for
genetic material isolation (JAK2 mutation). The clinical data of each patient were
related to each other and correlated with the molecular data.
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The plasticity of melanoma cell invasiveness / The plasticity of melanoma cell invasivenessGandalovičová, Aneta January 2016 (has links)
and keywords: During metastasis, cancer cells can invade the extracellular matrix using various strategies. When invading individually, they employ either the amoeboid invasion mode, during which the cell body dynamically deforms by enhanced contractility to squeeze through pores within the matrix, or protease dependent mesenchymal migration that takes advantage of the possibility to digest the surrounding matrix. Cells migrating in one mode can actively switch to the other by mesenchymal-amoeboid (MAT) or amoeboid-mesenchymal transitions (AMT). This enables escape mechanisms and considerably complicates anti-metastatic treatment. It is well known that Rho GTPases are master regulators of cytoskeleton re-arrangements and thus, unsurprisingly, play a major role in both invasion modes and can directly drive the transitions. However, upstream activation of these pathways is still largely unclear. This thesis aimed to optimize 3D conditions suitable for studying plasticity of cell invasion in vitro, establish AMT and MAT in melanoma cells based on manipulation of Rho GTPases and verify novel candidates regulating cell invasion plasticity based on previous RNA sequencing of cells before and after MAT. Last, by synthesis of published data, results from sequencing and new findings presented in this...
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Etické bankovníctvo / Ethical bankingPrekopová, Dominika January 2013 (has links)
Thesis is concerned with ethical banking -- as an alternative to conventional banks. First part of the thesis deals with ethics in banking in general, next parts are focused on the essential characteristics of ethical banking and characterization and analysis of two ethical banks. In the final part, thesis discusses the possibility of establishing ethical banking in the Czech Republic, discusses the barriers that exist in the Czech Republic and the possibilities for the future development of this alternative banking in the country.
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THE ROLE OF PROLACTIN RECEPTOR SIGNALING IN LIVER HOMEOSTASIS AND DISEASEJennifer Abla Yanum (11157624) 06 August 2021 (has links)
<p>Functioning as a “powerhouse”, the liver adapts to the
metabolic needs of the body by maintaining a homeostatic balance. Prolactin
receptor (PRLR) has been found
to have a copious existence in the liver. Having established a well-defined role in both reproductive
and endocrine systems, the role of this transmembrane protein in hepatocytes is
yet to be elucidated. Due to its abundant nature, we hypothesized that PRLR is
required for maintaining hepatic homeostasis and plays a role in liver
diseases. To test this hypothesis, we defined two specific aims. The first was
to explore whether PRLR loss-of-function affects liver structure and function
in physiological conditions. The second was to determine whether PRLR is
associated with liver pathology. We deleted the <i>Prlr</i> gene specifically in hepatocytes using a virus-based approach
and evaluated liver function, transcriptome, and activities of downstream signaling
molecules. Due to the absence of PRLR, we found that the urea cycle was
disrupted, concomitant with excessive accumulation of urea in the blood; 133 genes exhibited
differential expression, largely associated with hepatocyte structure,
metabolism, and inflammation; and the activities of STAT3 and 5 were reduced. The
results signify that PRLR indeed plays a homeostatic role in the liver. We also
used <i>Prlr</i><sup>+/-</sup> mice to
assess whether the loss of one allele of the <i>Prlr</i> gene alters maternal hepatic adaptations to pregnancy. As a
result, in the pre-pregnancy state and during the first half of gestation, the
expression of maternal hepatic PRLR protein was reduced approximately by half
owing to <i>Prlr</i> insufficiency. However,
during the second half of pregnancy, we observed compensatory upregulation of
this molecule, leading to minimal
interference in
STAT 3 and 5 signaling and liver size. Contrary to a previous study in the
breast and ovary, our results suggest that one allele of <i>Prlr</i> may be sufficient for the maternal liver to respond to this physiological
stimulus (pregnancy). Furthermore, we examined the expression and activity of
PRLR in fatty as well as cholestatic livers. Using a high fat diet, we induced non-alcoholic
fatty liver disease (NAFLD).
Strikingly and for the first time, we discovered that the short isoform of PRLR
(PRLR-S) was completely inactivated in response to NAFLD, whereas the long isoform
remained unchanged. This finding strongly suggests the involvement of PRLR-S in
lipid metabolism. We also postulate that PRLR-L may be the major regulator of
STAT signaling in the liver, consistent with other reports. Lastly, we induced
extrahepatic cholestasis via bile duct ligation (BDL) in mice. As this liver
disease progressed, the expression of both isoforms of PRLR generally declined
and was surprisingly accompanied by increased STAT 3 and 5 activity. The data
suggests that PRLR participates in this disease progression, with a
disconnection between PRLR signaling and STAT proteins. Collectively, our preliminary
studies suggest that PRLR signaling is required to maintain liver homeostasis
and more prominently, is involved in liver diseases, especially NAFLD. These
findings lay a foundation for our future studies.</p>
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The Role of Prolactin Receptor Signaling in Liver Homeostasis and DiseaseYanum, Jennifer Alba 08 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Functioning as a “powerhouse”, the liver adapts to the metabolic needs of the body by maintaining a homeostatic balance. Prolactin receptor (PRLR) has been found to have a copious existence in the liver. Having established a well-defined role in both reproductive and endocrine systems, the role of this transmembrane protein in hepatocytes is yet to be elucidated. Due to its abundant nature, we hypothesized that PRLR is required for maintaining hepatic homeostasis and plays a role in liver diseases. To test this hypothesis, we defined two specific aims. The first was to explore whether PRLR loss-of-function affects liver structure and function in physiological conditions. The second was to determine whether PRLR is associated with liver pathology. We deleted the Prlr gene specifically in hepatocytes using a virus-based approach and evaluated liver function, transcriptome, and activities of downstream signaling molecules. Due to the absence of PRLR, we found that the urea cycle was disrupted, concomitant with excessive accumulation of urea in the blood; 133 genes exhibited differential expression, largely associated with hepatocyte structure, metabolism, and inflammation; and the activities of STAT3 and 5 were reduced. The results signify that PRLR indeed plays a homeostatic role in the liver. We also used Prlr+/- mice to assess whether the loss of one allele of the Prlr gene alters maternal hepatic adaptations to pregnancy. As a result, in the pre-pregnancy state and during the first half of gestation, the expression of maternal hepatic PRLR protein was reduced approximately by half owing to Prlr insufficiency. However, during the second half of pregnancy, we observed compensatory upregulation of this molecule, leading to minimal interference in STAT 3 and 5 signaling and liver size. Contrary to a previous study in the breast and ovary, our results suggest that one allele of Prlr may be sufficient for the maternal liver to respond to this physiological stimulus (pregnancy). Furthermore, we examined the expression and activity of PRLR in fatty as well as cholestatic livers. Using a high fat diet, we induced non-alcoholic fatty liver disease (NAFLD). Strikingly and for the first time, we discovered that the short isoform of PRLR (PRLR-S) was completely inactivated in response to NAFLD, whereas the long isoform remained unchanged. This finding strongly suggests the involvement of PRLR-S in lipid metabolism. We also postulate that PRLR-L may be the major regulator of STAT signaling in the liver, consistent with other reports. Lastly, we induced extrahepatic cholestasis via bile duct ligation (BDL) in mice. As this liver disease progressed, the expression of both isoforms of PRLR generally declined and was surprisingly accompanied by increased STAT 3 and 5 activity. The data suggests that PRLR participates in this disease progression, with a disconnection between PRLR signaling and STAT proteins. Collectively, our preliminary studies suggest that PRLR signaling is required to maintain liver homeostasis and more prominently, is involved in liver diseases, especially NAFLD. These findings lay a foundation for our future studies.
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Inactivation Of Type I IFN Jak-STAT Pathway In EBV LatencyNing, Shunbin, Wang, Ling 05 August 2016 (has links) (PDF)
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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