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1
Paul, Christine E. "Analysis of p75NTR-dependent apoptotic pathways and of p75NTR gene products." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19468.
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The p75 neurotrophin receptor (p75NTR) binds members of the neurotrophin family and plays important roles in the regulation of neuronal survival, apoptosis and growth during development and after nervous system injury. Many in vitro and in vivo studies have shown that p75NTR induces cell death, though the signaling events that link p75NTR activation to apoptosis are not thoroughly understood. p75NTR-dependent apoptosis is associated with an increase in Rac and Jun kinase (JNK) activity, and recent work from our laboratory has shown that the p75NTR interactor, NRAGE, activates a mitochondrial death pathway involving JNK-dependent cytochrome C release and activation of Caspase-9, Caspase-7 and Caspase-3. Despite this progress, several important details of p75NTR apoptotic signaling remain unknown. In particular, it is unclear what targets of p75NTR-dependent JNK activation result in mitochondrial cytochrome C release and caspase activation. BH3-domain-only proteins are members of the Bcl-2 family that induce the association of Bax and Bak which in turn facilitate release of mitochondrial proteins such as cytochrome C into the cytosol. Transcriptional activation of BH3-domain-only genes through c-Jun- or p53-dependent pathways is implicated in apoptosis in neuronal and non-neuronal systems. In the first part of this thesis, I examined whether p75NTR-induced apoptosis is correlated with accumulation of BH3-domain-only gene products. U373 human glioma cells and mouse cortical neurons were infected with adenovirus expressing p75NTR to constitutively activate p75NTR-dependent pathways, and alterations in mRNA levels of the BH3-domain-only family members Bim, Bmf, Hrk, Bik, Puma, and Noxa were determined by RT-PCR. The results from these experiments showed that p75NTRmediated cell death did not result in BH3-domain-only gene transcription. Subsequent studies in our laboratory established that the BH3-domain-only protein, Bad, is phosphorylated on Serine 128 in a JNK-dependent manner, and that this phosphorylation is a critical component of p75NTR-dependent apoptosis. The generation of animals that lack p75NTR expression has been a critical advance in understanding the in vivo role of this receptor. In the second part of this thesis, I analyzed the recently created p75NTRExonlv-/- mice, which were shown to produce a null mouse lacking all p75NTR gene products, in contrast to the previously constructed p75NTRExon1"-/- mouse, which maintains expression of an alternatively spliced form of p75NTR (s-p75NTR). Our studies revealed that 75NTRExonIV-/- mice continue to express a p75NTR gene product that encodes a truncated protein containing the p75NTR extracellular stalk region together with the entire transmembrane and intracellular domains. The gene product is initiated from a cryptic Kozak consensus/initiator ATG sequence within a region of Exon IV located 3' to the pGK-Neo insertion site, likely as a result of enhancer elements within pGK-Neo cassette. Characterization of this protein product indicated that it localized to the plasma membrane and overexpression of the p75NTRExonIV fragment in heterologous cells resulted in activation of JNK and cleavage of Procaspase 3, indicating that it can mediate pro-apoptotic effects in vivo. These results indicate that aspects of the p75NTRExonIV-/- phenotype may reflect a gain-of-function mutation rather than a loss of p75NTR function.
2
Kanning, Kevin C. "Characterization of the p75NTR/NRH subfamily /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/10665.
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Hucho, Tim. "Der Neurotrophinrezeptor p75NTR eine biochemische Untersuchung /." [S.l.] : [s.n.], 2002. http://www.diss.fu-berlin.de/2002/115/index.html.
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Schweigreiter, Rüdiger. "Untersuchungen über die funktionelle Rolle des Neurotrophinrezeptors p75NTR." Diss., lmu, 2002. http://nbn-resolving.de/urn:nbn:de:bvb:19-8187.
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Bandoła, Joanna, Cornelia Richter, Martin Ryser, Arshad Jamal, Michelle P. Ashton, Bonin Malte von, Matthias Kuhn, et al. "Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230813.
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Plasmacytoid dendritic cells (pDCs) regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR) by the antigen-presenting pDCs, mediated by toll-like receptor (TLR) 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders.
6
Wilmet, Jean-Philippe. "Etude proteomique du recepteur p75NTR dans le cancer du sein." Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10060/document.
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Le facteur de croissance neurotrophique NGF (Nerve Growth Factor) est un facteur mitogène et de survie pour les cellules de cancer du sein alors qu’il est sans effet sur la croissance des cellules épithéliales mammaires normales. Ce facteur de croissance agit sur ses cellules cibles par l’intermédiaire de deux récepteurs : TrkA, qui est un récepteur tyrosine kinase, et p75NTR, dépourvu d’activité catalytique intrinsèque. Le NGF stimule la survie des cellules cancéreuses mammaires via p75NTR en activant le facteur de transcription NF-ĸB. Au cours de mes travaux de thèse, je me suis tout d’abord appliqué à décrire les modifications du protéome induites par une surexpression de ce récepteur p75NTR. Pour cela, nous avons établi une lignée cellulaire MCF-7 surexprimant stablement le récepteur p75NTR. Par la suite, une étude par électrophorèse bidimensionnelle suivie par une analyse par spectrométrie de masse de type MALDI-TOF/TOF a été réalisée en comparant des cellules non stressées à des cellules induites en apoptose grâce à l’apoptogène TRAIL (TNF-related-apoptosis-inducing-ligand). Au cours de cette étude, nous avons pu mettre en évidence un certain nombre de protéines régulées par la présence de p75NTR en condition d’apoptose comme les cytokératines 8, 18 et 19, la protéine chaperonne HSP27 ou bien encore la protéine ribosomale RPLP0. Ces résultats suggèrent l’importance d’une réorganisation de ces protéines afin que p75NTR puisse effectuer son effet de survie. L’autre partie de mes travaux a consisté en une étude spécifique des partenaires de signalisation de p75NTR. Pour ce faire, nous avons décidé d’appliquer la stratégie TAP-Tag (Tandem Affinity Purification-Tag), une approche de protéomique fonctionnelle, au récepteur membranaire p75NTR. Une analyse différentielle de plusieurs conditions de culture par spectrométrie de masse de type nanoLC-MS/MS a abouti à l’obtention d’une liste de partenaires potentiels de signalisation de p75NTR dans un contexte de survie cellulaire. Cependant, l’implication fonctionnelle de ces protéines doit être confirmée. L’ensemble de ces travaux a permis d’ouvrir de nouvelles pistes de recherche pour comprendre à la fois les mécanismes cellulaires mis en œuvre lors de la survie des cellules cancéreuses mammaires, mais aussi les partenaires potentiels de signalisation du récepteur p75NTRThe growth factor NGF (nerve growth factor) is a mitogenic and survival factor for breast cancer cells but has no effect on normal epithelial mammary cell growth. This growth factor acts on breast cancer cells via two receptors : TrkA, a tyrosine kinase receptor, and p75NTR, which has no catalytic activity. NGF promotes breast cancer cells survival via p75NTR by activation of the transcriptional factor NF-κB. In the first time of my thesis work, I have described the proteome modification induced by an overexpression of p75NTR in apoptotic stress-induced breast cancer cells. We established a p75NTR overexpressing MCF-7 cell line. Thus, we investigated, by two dimensional electrophoresis followed by MALDI-TOF/TOF based mass spectrometry analysis, the proteome modification induced by the pro-apoptotic agent TRAIL (TNF-related-apoptosis-inducing-ligand). We describe some proteins regulated by p75NTR in an apoptosis condition like cytokeratin 8, 18 and 19, the HSP27 and the ribosomal protein RPLP0. These results show that the rearrangement of those proteins is associated to the survival effect of p75NTR in breast cancer cells. In a second part, we tried to identify the specific proteins partners of p75NTR for its survival pathway. For that, we applied the TAP-tag (tandem affinity purification tag) strategy, a functional proteomic approach, to the p75NTR receptor. A differential analysis by nanoLC-MS/MS mass spectrometry was conducted and we obtained a list of potentials proteins partners of the p75NTR activated survival pathway. The functional involvement of these proteins should be confirmed. Together, our work provides new data on the cellular mechanisms involved in the survival of breast cancer cells and also on the proteins partners implicated in p75NTR signaling
7
Riffault, Baptiste. "Plasticité GABAergique et épilepsie : focus sur le proBDNF." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4005/document.
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Le facteur neurotrophique dérivé du cerveau (BDNF) synthétisé sous la forme d'un précurseur (proBDNF) qui peut être clivé pour donner sa forme mature (mBDNF). Le mBDNF et le proBDNF produisent des réponses physiologiques opposées par l'activation de deux classes distinctes de récepteurs transmembranaires : respectivement, le récepteur TrkB et p75NTR. Le ratio mature/pro-BDNF est un élément important impliqué dans la plasticité synaptique, la formation des circuits neuronaux et in fine les fonctions cognitives. Les altérations dans ce clivage peuvent ainsi expliquer l’émergence de conditions pathologiques post-lésionnelles, comme la mort cellulaire induite par un état de mal épileptique. Au cours de ma thèse, j'ai montré que l'altération de la maturation du BDNF in vitro, provoquait, via le récepteur p75NTR, une altération de l’activité GABAergique. Par ailleurs, au cours des crises d'épilepsies, les réponses dépolarisantes et excitatrices du GABA, soutenus par la baisse d’expression et d’activité du co-transporteur KCC2, ont été rapportées. Ainsi, in vivo, j’ai montré que la voie proBDNF/p75NTR module l'homéostasie chlore au cours du développement et dans des processus d’épileptogenèse. Pendant le développement, l’activation de la voie proBDNF/p75NTR contrôle le passage d’un GABA immature dépolarisant à un GABA mature hyperpolarisant via KCC2. Pendant l’épileptogenèse, le proBDNF via p75NTR contribuerait à l’hyperexcitabilité des réseaux neuronaux. De plus, le blocage de p75NTR permet de réduire le nombre de crises épileptiques. En conclusion, proBDNF/p75NTR est un facteur clé dans la séquence maturative du GABA et dans la mise en place de l’épilepsie du lobe temporalThe brain-derived neurotophic factor (BDNF) is synthesized as a precursor (proBDNF) that can be processed intracellularly to the mature form (mBDNF). mBDNF and proBDNF are assumed to produce opposing physiological responses mediated by the activation of two distinct classes of transmembrane receptors, the TrkB and the p75NTR respectively. The proteolysis of proBDNF is crucial for cognitive functions; its impairment may account for the emergence of brain disorders such as epilepsy. During my thesis, I showed that alteration in BDNF maturation in vitro triggers an up-regulation of p75NTR, inducing a disruption of GABAergic transmission. Moreover, in epilepsy, depolarizing and excitatory GABAergic responses, due to alteration of KCC2, have been reported. Interestingly, I described novel insights into the proBDNF/p75NTR mechanisms and function in vivo in modulating chloride homeostasis during the development of neuronal networks and in the pathogenesis of epilepsy. In physiological conditions, p75NTR activation by proBDNF may be a key regulator in shaping neural circuitry and synaptic plasticity. Moreover, I have shown that proBDNF/p75NTR to mBDNF/TrkB ratio may control the timing of the developmental shift of GABA depolarizing to hyperpolarizing. During epileptogenesis, proBDNF via p75NTR alters the excitatory/inhibitory equilibrium thereby enhancing neuronal activity through the inhibition of KCC2 function. Hence, blockade of p75NTR can prevent some of the epileptogenic mechanisms. Altogether, these data provide the first compelling evidence that proBDNF disrupts the GABA excitatory/inhibitory developmental sequence, which then favors the emergence of epileptic disorders
8
Allington, Christopher. "Characterizing the interaction of NGF with p75ntr in chick retinal cells." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0018/MQ52871.pdf.
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Okumura, Tomoyuki. "Neurotrophin receptor p75NTR characterizes human esophageal keratinocyte stem cells in vitro." Kyoto University, 2004. http://hdl.handle.net/2433/147538.
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Howell, Jenny L. "BH-3-domain-only proteins are key regulators of p75NTR-mediated apoptosis." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81343.
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The p75 neurotrophin receptor (p75NTR) is a member of the Tumor Necrosis Factor Receptor (TNFR) superfamily. Similar to TNFR members, p75NTR has been reported to mediate programmed cell death (PCD) in a variety of systems, including during development and in response to central nervous system (CNS) injury. However, in contrast to TNFR members, which typically signal via Caspase 8 to elicit cell death, studies conducted in our laboratory have demonstrated that p75NTR induces cell death via an intrinsic mitochondrial death cascade involving c-Jun N-terminal kinase (JNK) activation, mitochondrial cytochrome c release and activation of Caspases 9, 3 and 6.In an effort to determine the mechanism by which JNK communicates with the mitochondria, we examined downstream targets of JNK including the BH3-domain-only proteins. BH3-domain-only proteins are members of the Bcl-2 family of proteins, which have been dubbed mitochondrial gate-keepers, referring to their ability to regulate release of mitochondrial proteins such as cytochrome c in response to apoptotic stimuli. Our studies revealed that p75NTR overexpression does not transcriptionally upregulate BH3-domain-only proteins, rather, it results in phosphorylation of BH3 proteins, Bad and BimEL at Serines 128 and 65, respectively, in a JNK-dependent manner. Furthermore, through loss of function studies employing RNA interference constructs targeting either Bad or Bim, as well as Bad S 128A- or BimEL S65A dominant negative constructs, we demonstrated that Bad is critical for p75NTR-mediated apoptosis, while BimEL may contribute but is less critical. Together, these studies reveal key roles for BH3-domain-only proteins in p75NTR-mediated apoptosis.
11
Papa, Antonella <1978>. "Analisi funzionale dei recettori per le neurotrofine p75NTR e Trka in neuroblastoma." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/679/1/Tesi_Papa_Antonella.pdf.
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The biological complexity of NGF action is achieved by binding two distinct Neurotrophin
receptors, TrkA and p75NTR. While several reports have provided lines of evidence on the
interaction between TrkA and p75NTR at the plasma membrane, much fewer data are
available on the consequence of such an interaction in terms of intracellular signaling. In
this study, we have focused on how p75NTR may affect TrkA downstream signaling with
respect to neuronal differentiation. Here, we have shown that cooperation between p75NTR
and TrkA results in an increased NGF-mediated TrkA autophosphorylation, leads to a
sustained activation of ERK1/2 and accelerates neurite outgrowth. Interestingly, neurite
outgrowth is concomitant with a selective enhancement of the AP-1 activity and the
transcriptional activation of genes such as GAP-43 and p21(CIP/WAF), known to be
involved in the differentiation process. Collectively, our results unveil a functional link
between the specific expression profile of neurotrophin receptors in neuronal cells and the
NGF-mediated regulation of the differentiation process possibly through a persistent ERKs
activation and the selective control of the AP-1 activity. In our studies we discuss the
functional role of the neurotrophin receptor p75NTR and TrkA in a ligand-dependent signal
transduction.
It is known that p75NTR is also involved in the mediation of cell death ligand dependent.
Here we show for the first time that the membrane receptor p75NTR, upon binding to b-
Amyloid (Ab) peptide, is able to transduce a cytotoxic signal through a mechanism very
similar to the one adopted by Tumor Necrosis Factor Receptor 1 (TNFR1), when activated
by TNFa. We define that in neuroblastoma cell line Ab cytotoxicity signals through a
pathway depending on p75NTR death domain (DD), mostly through some specific
conserved residues. We identified that TRADD is the first interactor recruiting to the
membrane and activates JNK and NF-kB transcription factors. Since Ab is defined as the
most important aetiologic element associated with the Alzheimer’s Disease (AD),
characterization of the mechanism involved in the mediation of the neurodegeneration can
suggest also new therapeutic approaches.
12
Papa, Antonella <1978>. "Analisi funzionale dei recettori per le neurotrofine p75NTR e Trka in neuroblastoma." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/679/.
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The biological complexity of NGF action is achieved by binding two distinct Neurotrophin
receptors, TrkA and p75NTR. While several reports have provided lines of evidence on the
interaction between TrkA and p75NTR at the plasma membrane, much fewer data are
available on the consequence of such an interaction in terms of intracellular signaling. In
this study, we have focused on how p75NTR may affect TrkA downstream signaling with
respect to neuronal differentiation. Here, we have shown that cooperation between p75NTR
and TrkA results in an increased NGF-mediated TrkA autophosphorylation, leads to a
sustained activation of ERK1/2 and accelerates neurite outgrowth. Interestingly, neurite
outgrowth is concomitant with a selective enhancement of the AP-1 activity and the
transcriptional activation of genes such as GAP-43 and p21(CIP/WAF), known to be
involved in the differentiation process. Collectively, our results unveil a functional link
between the specific expression profile of neurotrophin receptors in neuronal cells and the
NGF-mediated regulation of the differentiation process possibly through a persistent ERKs
activation and the selective control of the AP-1 activity. In our studies we discuss the
functional role of the neurotrophin receptor p75NTR and TrkA in a ligand-dependent signal
transduction.
It is known that p75NTR is also involved in the mediation of cell death ligand dependent.
Here we show for the first time that the membrane receptor p75NTR, upon binding to b-
Amyloid (Ab) peptide, is able to transduce a cytotoxic signal through a mechanism very
similar to the one adopted by Tumor Necrosis Factor Receptor 1 (TNFR1), when activated
by TNFa. We define that in neuroblastoma cell line Ab cytotoxicity signals through a
pathway depending on p75NTR death domain (DD), mostly through some specific
conserved residues. We identified that TRADD is the first interactor recruiting to the
membrane and activates JNK and NF-kB transcription factors. Since Ab is defined as the
most important aetiologic element associated with the Alzheimer’s Disease (AD),
characterization of the mechanism involved in the mediation of the neurodegeneration can
suggest also new therapeutic approaches.
13
Gschwendtner, Andreas. "Regulation, zelluläre Lokalisation und Funktion des Neurotrophinrezeptors p75NTR bei der Regeneration von Motoneuronen." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972240187.
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Scott, Angela Lee. "The role of p75NTR in axonal regeneration and intraspinal plasticity following spinal deafferentation." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/13765.
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Following spinal cord injury (SCI), functional recovery is extremely limited in adult mammals. This lack of recovery is reflective of the failure of axons to regenerate and the incapacity of uninjured neurons to compensate for the lost connections. In animal models of SCI, the administration of neurotrophic factors such as neurotrophins promotes both the regeneration and sprouting of injured and uninjured axons. Neurotrophins elicit these growth-promoting effects through tropomyosin-related kinase (Trk) receptors. However, neurotrophins also interact with a pan neurotrophin receptor, p75NTR. Several functions of the p75NTR receptor have been reported, but its role in neurotrophin-mediated signalling following SCI remains unclear.
To determine the role of p75NTR in neurotrophin-mediated axonal regeneration and sprouting within the CNS, I assessed anatomical changes and functional outcomes following spinal deafferentation in mice lacking the neurotrophin-binding domain of p75NTR (p75-/-) and in wild-type littermates (p75+/+). Regeneration of sensory axons was significantly greater in p75-/- mice, and resulted in functional re-connection with dorsal horn neurons. Axonal regeneration in the p75-/- mice was neurotrophin-dependent, and dis-inhibited by the absence of p75NTR expression on glial cells following injury. These findings indicate that glial expression of p75NTR restricts neurotrophin availability to the extent that it prevents spontaneous sensory axon regeneration into the spinal cord.
Intraspinal sprouting of uninjured neuronal processes following dorsal root injury was also evaluated in p75+/+ and p75-/- mice. The density of sprouting axons was significantly enhanced by the application of exogenous neurotrophins and dis-inhibited by the absence of p75NTR. Dendritic density was also promoted by exogenous neurotrophin treatment, but was not affected by the absence of p75NTR. Together, these results demonstrate that p75NTR restricts the intraspinal sprouting of neurotrophin-responsive axons, but not dendrites, within the injured spinal cord. Dis-inhibition of dendritic plasticity was, however, correlated to the antagonism of truncated TrkB receptor (TrkBT1) expression. Thus, the neurotrophin receptors p75NTR and TrkBT1 may differentially inhibit intraspinal sprouting of pre- and post-synaptic processes within the spinal cord following injury.
15
Matusica, Dusan, and matu0012@flinders edu au. "Regulation of p75NTR Trafficking by Neurotrophins in the NSC-34 Motor Neuron Cell Line." Flinders University. School Of Medicine, 2008. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20080808.115027.
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Neurotrophins are a family of growth factors necessary for the development and maintenance of the nervous system. They produce their effects through receptor mediated signaling mechanisms that are highly regulated by sophisticated intracellular transport networks. The impairment of intracellular trafficking of neurotrophins in motor neurons has been identified as one possible factor in the development of motor neuron diseases, but remains inadequately studied. Aided by advances in imaging technology and the development of more powerful and sensitive detection tools for in-vitro studies, the dynamics of intracellular transport of neurotrophins are beginning to be unraveled. However, a primary limiting factor in the study of neurotrophin-transport dynamics in motor neurons has been the lack of alternative and easily available in-vitro systems able to substitute the often difficult and costly primary motor neuron cultures.
The aim of this project was to develop a suitable motor neuron model using the NSC-34 cell line for the study of receptor mediated trafficking events through endosomal transport pathways. Successful evaluation and characterization of NSC-34 cells for motor neuron specific markers would result in the investigation of the p75 neurotrophin receptor (p75NTR) trafficking pathways in the presence of exogenous neurotrophins, with a variety of confocal imaging techniques.
Chapter 3 describes the optimisation of NSC-34 cell culture conditions through media modification and the development of a suitable growth substrate matrix, which significantly improved cell adhesion, differentiation and the ability to culture the cells for extended time periods in serum free conditions. Quantitative measurements of cell proliferation, culture viability, cell-body size and neurite length are described to highlight the increased value of the cell line for long-term culture and experiments examining a broad range of issues relevant to motor neurons.
In Chapter 4, multiple experimental approaches were used to extensively screen the NSC-34 cell line for the presence of motor neuron-specific markers, neurotrophin receptors and proteins involved in regulation of endosomal transport. This characterization established the presence of a developing motor neuron-like neurotrophin receptor profile (p75NTR, TrkB and TrkC), a genetic marker of developing motor neurons, cholinergic markers, proteins regulating transport within the endosomal pathway, and additional proteins previously shown to directly interact with neurotrophin receptors, including sortilin, and the lipid raft associated ganglioside GT1b. Furthermore, evidence is provided that NSC-34 cells undergo apoptosis in response to exogenous nerve growth factor (NGF) or neurotrophin-3 (NT-3), but not brain derived neurotrophic factor (BDNF) or neurotrophin-4 (NT-4). In addition characterization of mouse specific p75NTR antibodies is presented to establish their suitability for internalization studies without altering the binding of exogenous neurotrophins to the receptor.
Subsequent confocal microscopy examination focusing on p75NTR trafficking in Chapter 5 revealed that internalization and intracellular transport of this receptor is regulated by exogenous neurotrophins at the cell surface where ligand binding and internalization occur, and in endosomal compartments where the bulk of receptors and ligands are targeted to their specific destinations. Evidence is provided showing that p75NTR internalization is altered in the presence of NGF, NT-3, or NT-4, but not BDNF, and the receptor is diverted into non-clathrin mediated endosomal pathways in response to NGF but not BDNF. Immunofluorescence confocal microscopy suggests that p75NTR recycles to the plasma membrane in a Rab4 GTPase dependent manner in the absence of neurotrophins. Addition of neurotrophins diverted p75NTR from the recycling Rab4 positive pathway, into EEA-1 positive sorting endosomes in the presence of NGF or NT-3, or lysosomal degradation in the presence of BDNF or NT-4.
This study clearly demonstrates the suitability of the NSC-34 cell line as an alternate in-vitro system for the study of motor neuron biology, particularly the study of neurotrophin receptor trafficking. Taken together the results represented in this study suggest for the first time, that the fate of the p75NTR receptor depends on which neurotrophin is bound. These findings have important implications for understanding the dynamic mechanisms of action of p75NTR in normal neuronal function, and may also offer further insight into the potential role of neurotrophins in the treatment of neurodegenerative diseases.
16
Walsh, Erin. "Crossreactivity of alpha9beta1 integrin with p75NTR in modulation of proinvasive activities of glioma cells." Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/143048.
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BiologyPh.D.
Gliomas are the most common and difficult to treat tumors of the central nervous system. Current treatments often fail to slow progression of disease due to the high invasive nature of glioma leading to a high percentage of recurrence. Our previous studies have demonstrated that the levels of alpha; 9 beta; 1 integrin found on high grade glioma were significantly increased in comparison to normal brain tissue where the levels were negligible. We also found that interaction between alpha; 9 beta; 1 integrin and nerve growth factor (NGF) plays a major role in progression of experimental tumor. Another receptor for NGF the common neurotrophin receptor p75NTR is also overexpressed in high grade glioma. p75NTR forms a high affinity complex with the specific NGF receptor, TrkA leading to an increase in cell proliferation and survival. In the absence of an association, p75NTR is involved in transferring pro-apoptotic signals through the JNK pathway. We have found that the α 9 integrin subunit of α 9 β 1 forms a stable, cation independent complex with p75NTR on the cell membrane of glioma both in vitro using glioma derived immortalized cells lines and in vivo using glioma tissue. The co-expression of p75NTR with α 9 β 1 integrin led to optimization of integrin-dependent cellular activities such as cell survival, proliferation, and migration. Co-expression of p75NTR was also required for implanted glioma cells to migrate in a glioma-like perivascular manner away from the site of implantation as was seen in the in vivo quail chorioallantoic membrane assay.
Temple University--Theses
17
Verbeke, Stéphanie. "Étude des voies de signalisation du récepteur p75NTR impliquées dans la croissance des cellules de cancer du sein." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10136/document.
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Les données accumulées par notre laboratoire montrent une action pro-tumorale des neurotrophines dans le cancer du sein via notamment des effets anti-apoptotiques du NGF, du BDNF et de la NT4/5. Ces effets sont tous relayés par leur récepteur commun p75NTR, je me suis donc appliquée à préciser le rôle de ce récepteur et sa signalisation dans le cancer du sein. Pour cela, nous avons établi une lignée cellulaire surexprimant de manière inductible p75NTR. Ce modèle d’étude a permis de montrer que la survie induite par le récepteur était associée à une inhibition de la voie intrinsèque de l’apoptose. De plus, p75NTR ralentit la prolifération en provoquant une accumulation des cellules dans les phases G0/G1 du cycle cellulaire. In vitro, ces deux effets passent par une augmentation de p21Waf1 car son invalidation par siRNA, non seulement restore la prolifération, mais abolit totalement la survie, faisant de p21Waf1 une protéine clé dans la signalisation de p75NTR. In vivo, la surexpression de p75NTR conduit à une augmentation du volume tumoral et à une résistance accrue à l’apoptogène TRAIL. Enfin, l’analyse de la protéolyse de p75NTR montre qu’il subit deux clivages successifs dans les cellules cancéreuses mammaires. Le premier clivage réalisé par l’enzyme ADAM17/TACE semble indispensable à son effet anti-apoptotique alors que le second clivage n’intervient pas, suggérant plutôt un processus de dégradation du récepteur. Ces travaux ont permis d’approfondir les mécanismes d’action de p75NTR dans les cellules cancéreuses mammaires et suggèrent que ce récepteur pourrait contribuer à la croissance tumorale en favorisant la résistance aux drogues anticancéreusesOur laboratory has shown a pro-tumoral action of the neurotrophins in breast cancer especially by the anti-apoptotic effects of NGF, BDNF and NT4/5. These effects are all mediated by their common receptor p75NTR. My thesis work has therefore been to elucidate further the role of p75NTR in breast cancer cells and its signaling. For this purpose, we established breast cancer cells which stably overexpress p75NTR in an inducible manner. This model allowed us to show that its pro-survival effect is associated with an inhibition of the intrinsic pathway of apoptosis. Moreover, p75NTR slows down the cell growth through a cell accumulation in G0/G1 phases. Interestingly, these both effect are mediated by p21Waf1 since its inhibition by siRNA not only restores proliferation but also abolishes the pro-survival effect of p75NTR, indicating the key role of p21waf1 in the biological functions of p75NTR. In a SCID mice xenograft model, p75NTR overexpression favors tumor growth and strongly increases tumor resistance to TRAIL treatment. Finally, the study of p75NTR proteolysis has shown that this receptor undergoes two sequential cleavages in breast cancer cells. The first cleavage by the enzyme ADAM17/TACE is essential to its anti-apoptotic effect. Meanwhile, the second cleavage by the γ-secretase complex doesn’t seem to be involved rather suggesting a degradation process. Together, our findings have improved the knowledge of p75NTR functions in breast cancer cells and suggest that p75NTR overexpression in breast tumor cells could favor tumor survival and contribute to tumor resistance to drugs
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Kourdougli, Nazim. "Hippocampal structural reactive plasticity in a rat model of temporal lobe epilepsy : chloride homeostasis as a keystone." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4091.
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Cette thèse a pour objectif spécifique d’explorer les événements précoces pouvant être à l’origine du bourgeonnement aberrant des fibres moussues (FM) du gyrus denté, une réorganisation majeure dans l’Epilepsie du Lobe Tempora (ELT). Nous avons utilisé le modèle pilocarpine d’ELT chez le rat afin de montrer que la transmission GABAergique jouait un rôle prépondérant dans la formation des FM aberrantes au cours de l’épileptogenèse. Ceci étant due à une altération de l’homéostasie chlore, suite à une augmentation de l’expression du co-transporteur NKCC1 et une diminution du co-transporteur KCC2. Nos résultats ont démontré que le récepteur aux neurotrophines p75NTR était un médiateur de l’action trophique de la réponse GABAergique dépolarisante sur le bourgeonnement aberrant des FM. Le blocage de l’action dépolarisante de la transmission GABAergique via l’utilisation de la bumétanide, a permis de réduire le bourgeonnement aberrant des MF en réduisant l’expression de p75NTR. Enfin, l’application transitoire de la bumétanide au cours de l’épileptogenèse a abouti à la réduction du nombre de crises récurrentes et spontanées au cours de la phase chronique d’ELT chez le rat. Ce travail a permis de dévoiler les mécanismes moléculaires sous-jacents de la réorganisation du réseau neuronal glutamatergique consécutif à une crise inaugurale dans un modèle d’ELT. Dans l'ensemble, cette thèse apporte un éclairage nouveau sur l’importance de l’interaction de la signalisation GABAergique avec les neurotrophines afin d’orchestrer la plasticité réactive au sein de l’hippocampe dans TLEThe present dissertation undertakes to investigate the early triggering events of the mossy fiber sprouting (MFS) in the dentate gyrus, a hallmark of hippocampal reactive plasticity in Temporal Lobe Epilepsy (TLE). We used the rat pilocarpine model of TLE to show that altered GABAA receptor-mediated transmission play a key role in the formation of early ectopic MFS during epileptogenesis. This is likely due to a compromised chloride homeostasis, as a result of increased expression of chloride loader NKCC1 and downregulation of the neuronal chloride extruder KCC2. We next addressed the mechanistic action of depolarizing GABAAR responses with regard to neurotrophin signaling. Our findings uncovered that the pan neurotrophin receptor p75 (p75NTR) mediated the sculpting action of depolarizing GABAAR responses on the ectopic MFS. Blockade of depolarizing GABAAR responses using the loop diuretic bumetanide reduced abnormal p75NTR subsequently decreased the ectopic MFS. Finally, transitory application of bumetanide during epileptogenesis resulted in reduction of spontaneous and recurrent seizures during the chronic phase of TLE. The rationale of this work is that unveiling the molecular mechanisms underlying the hippocampal post-seizure glutamatergic network rewiring will help to drive future novel therapeutic avenues involving chloride homeostasis and neurotrophin interplay. Overall, this dissertation shed a new light on how GABAergic transmission and neurotrophin signaling crosstalk can orchestrate reactive hippocampal plasticity in TLE
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Acuña, Rodríguez Eric M. "Efecto de NGF y P75NTR sobre el desarrollo folicular en ratas al termino del período reproductivo." Tesis, Universidad de Chile, 2008. http://www.repositorio.uchile.cl/handle/2250/105694.
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Memoria para optar el título de BioquímicoEl cese de la función ovárica está dado principalmente por la pérdida del número de folículos primordiales. Durante el envejecimiento, existe un decrecimiento en el número de folículos ováricos. En mujeres se ha establecido el periodo de subfertilidad después de los 37 años, cuando quedan menos de 100.000 folículos. En roedores, este período es caracterizado por disminución de la ciclicidad estral, del número de partos y de crías nacidas vivas por cada hembra. En este trabajo, se determinó el período de subfertilidad y el término del período reproductivo en ratas Sprague Dawley (SD). Desde los 8 meses se observaron cambios importantes en ratas, como disminución de estradiol y androstenediona, variación en los niveles de progesterona, aumento de la Noradrenalina (NA) ovárica y adrenal, además, de la disminución de la ciclicidad estral y fertilidad. El contenido intraovárico del factor de crecimiento nervioso (NGF), no cambia durante el período de subfertilidad. Sin embargo, aumenta significativamente a los 16 meses de edad, cuando la rata es infértil. Estos resultados permiten establecer el período de subfertilidad de la rata entre los 8 a 10 meses de edad. Después de esta caracterización se usaron ratas en el período de subfertilidad, para determinar si NGF y su receptor de baja afinidad p75NTR, son parte de un posible mecanismo que participa en este período. Para ello se administró localmente en el ovario una minibomba osmótica que infundió una mezcla de anticuerpo anti NGF con oligonucleótido antisentido contra mRNA de p75NTR . Después de 28 días de perfusión continua, se observó una sobreproducción de NGF intraovárico, el que posiblemente junto con el bloqueo de la traducción de p75NTR provocó: un aumento de androstenediona en plasma, pérdida de la ciclicidad estral, disminución del contenido de NA en médula adrenal, ganglio celíaco y ovario, encontrado al final del período observado. Además, hubo un aumento en el número de folículos saludables antrales y preantrales, y un aumento de estructuras quísticas, folículos tipo III y folículos luteinizados. La administración de la minibomba osmótica con anticuerpo contra NGF y el oligonucleótido antisentido tuvo un mayor efecto en los ovarios de rata de 8 meses que en los de 10 meses de edad y afecta a los dos ovarios por igual, tanto al que está conectado con la minibomba como al ovario contralateral. Los cambios morfológicos observados en ovario de rata de 8 meses de edad sugieren que un incremento en la actividad nerviosa simpática adelanta el envejecimiento reproductivo ovárico, proceso regulado por control neurotrófico intraovárico.
The cessation of reproductive function is mostly due to lost of primordial follicles pool. During aging, there is a decreased in the number of ovarian follicles. In women, the subfertility period was found from 37 years, when the number of follicles are smaller than 100.000. In rodents, this period is characterized for the lost of estrual cycling activity, decrease in the number of pups and deliveries by the female. In the present work, we determined the period of subfertility and the end of the reproductive period in Sprague Dawley (SD) rats. Since 8 month old we found important neuroendocrine changes in rats a such as decrease of estradiol and androstenedione, changes in progesterone, increase in ovarian and adrenal noradrenaline (NA). In addition, there was a decrease of estrual cyclicity and fertility. There were not changes in the nerve growth factor (NGF) at period of subfertility, but NGF was increased at 16 months, when the rat is infertile. Altogether these dates permitted us to define the period of subfertility betwen 8 to 10 months for the Sprague Dawley rat. After this characterization we used rats during the period of subfertility, to determine if NGF and its low affinity p75NTR receptor were involved in the possible mechanisms resulting in the end of ovary function. For that, we used Alzet osmotic minipumps to infuse one rat ovary with a mix of neutralizing antiserum to NGF in conjunction with an antisense oligodeoxynucleotide to mRNA p75 NGFR . After 28 days of continuous perfusion, we observed an overproduction of ovarian protein NGF, which together with the blockade of translation of p75NTR, could be the responsible of the: increase in serum androstenedione, lost of the cyclicity, decrease of NA content from the adrenal medulla, celiac ganglion and ovary, found at the end of observation. In addition, there was an increase in the number of antral and preantral healthy follicles and an increase in cystic structures; follicles type III and luteinizing follicles. The effect of the neutralizing antiserum to NGF with the antisense oligodeoxynucleotide to p75NTR was stronger in the ovary of rats of 8 month old than that in the ovary of rats of 10 month old. In both cases, the effect was the same for contralateral ovary (without miniosmotic pump). The morphological changes found in the ovary of rats of 8 month old suggest that an increasing sympathetic nerve activity accelerated ovarian reproductive aging in a process regulated by intraovarian neurotrophic control
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Asai, Tomoko. "Contents, structure, and functions of collagen-derived peptides in human blood after ingestion of collagen hydrolysate and gelatin." Kyoto University, 2020. http://hdl.handle.net/2433/253332.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第22496号
農博第2400号
新制||農||1076(附属図書館)
学位論文||R2||N5276(農学部図書室)
京都大学大学院農学研究科応用生物科学専攻
(主査)教授 佐藤 健司, 教授 菅原 達也, 准教授 豊原 治彦
学位規則第4条第1項該当
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TAVARES, Patrycy Assis Noronha. "Imunoreatividade para os receptores de neurotrofinas P75NTR e TrkA na zona subventricular de ratos adultos após isquemia estriatal." Universidade Federal do Pará, 2015. http://repositorio.ufpa.br/jspui/handle/2011/7997.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
FAPESPA - Fundação Amazônia de Amparo a Estudos e Pesquisas
Neurotrofinas são fatores de crescimento expressos por células do Sistema Nervoso, tanto durante o desenvolvimento quanto na vida adulta. O Fator de Crescimento Nervoso (NGF, do inglês- Nerve Growth Factor), o Fator Neurotrófico derivado do Cérebro (BDNF- do inglês- Brain-derived Neurotrophic Factor), Neurotrofina-3 (NT-3) e Neurotrofina-4/5 (NT-4/5), desempenham inúmeras funções relacionadas a maturação e resposta do tecido nervoso à patologias, como o Acidente Vascular Encefálico (AVE). Nesta condição, o aumento da expressão das neurotrofinas pode interferir no grau de neurogênese na Zona sub-ventricular (SVZ), bem como redirecionar a corrente migratória das Células-tronco Neurais Adultas (CTNAs) para a região isquêmica. A presença dos receptores de neurotrofinas p75NTR e TrkA, em CTNAs da SVZ, indica que eles podem participar na regulação da neurogênese nessa região. Neste trabalho, descrevemos a influência de uma isquemia experimental, através de uma microinjeção do peptídeo vasconstritor Endotelina-1, restrita ao estriado adjacente à SVZ; sobre o padrão de imunoreatividade para os receptores p75NTR e TrkA em diferentes tempos de sobrevida. Foi analisado o padrão histopatológico do estriado isquêmico e a citoarquitetura da SVZ, seguidos de análises imunoistoquímicas para os receptores. Inúmeras células p75NTR + foram encontradas na SVZ contra e ipsilateral ao sítio de injeção, ocorrendo uma redução de imunorreatividade no primeiro e terceiro dia após a isquemia. Raríssimas células TrkA+ foram encontradas na SVZ de ambos os grupos, porém, observamos inúmeros terminais axonais TrkA+ na SVZ ipsilateral a isquemia. Logo, após o processo isquêmico, houve espessamento da SVZ, concomitante à redução da imunorreatividade para o p75NTR e surgimentos de terminais axonais TrkA+.
Neurotrophins are growth factors expressed by cells of the nervous system both during development and in adulthood. The Nerve Growth Factor (NGF, the English- Nerve Growth Factor), brain-derived neurotrophic factor (English- BDNF- of Brain-Derived Neurotrophic Factor), Neurotrophin-3 (NT-3), Neurotrophin-4/5 ( NT-4/5), have many functions related to aging and response of nervous tissue to the pathology such as vascular accident (CVA). In this pathology, the increase of the neurotrophin expression can interfere with the degree of neurogenesis in the sub-ventricular zone (SVZ) and redirect the rostral migratory flow of Adult Neural Stem Cells (CTNAs) to the ischemic region. The presence of neurotrophin receptors TrkA and p75NTR in the CTNAs of SVZ indicates that they may participate in the regulation of neurogenesis in this region. Here we describe the influence of an experimental ischemia by microinjection of a vasconstritor Endothelin-1 peptide, which is restricted to the striatum adjacent SVZ; on the pattern of immunoreactivity for TrkA and p75NTR receptors in different survival times. The histopathological pattern of ischemic striatum and the cytoarchitecture of the SVZ, followed by immunohistochemical analysis to the receptors were analyzed. Numerous p75NTR + cells were found in the ipsilateral SVZ and against the injection site, with had a reduction in immunoreactivity at first and third day after ischemia. Few TrkA + cells were found in SVZ of both groups, however, many TrkA + axonal terminals were saw in the ischemic ipsilateral SVZ. Soon after the ischemic process, there was thickening of the SVZ, the concomitant reduction in immunoreactivity for p75NTR and TrkA + arisings of axonal terminals.
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Langevin, Christelle. "Caractérisation des domaines d'interaction impliqués dans la formation du complexe récepteur p75NTR-glycoprotéine du virus de la rage." Paris 11, 2003. http://www.theses.fr/2003PA114801.
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Le virus de la rage contient une seule glycoprotéine exprimée à la surface du virus. Cette glycoprotéine apparaît sous forme de trimères organisés en spicules. Un clonage par expression a permis l'identification du récepteur p75, récepteur de basse affinité du facteur de croissance neuronal NGF, comme récepteur neuronal de la glycoprotéine G (Tuffereau et coll. , 1998). Ce récepteur appartient à la famille des récepteurs au TNF, caractérisés par la répétition de domaines riches en cystéine dans l'ectodomaine, et la présence d'un domaine de mort dans la partie cytoplasmique. Notre travail a consisté à caractériser les sites d'interaction du complexe p75-G sur chacune des protéines. Nous avons montré que le premier domaine riche en cystéine du récepteur p75 est nécessaire et suffisant pour la fixation de la glycoprotéine. De plus, la glycoprotéine interagit avec p75 avec une haute affinité, sur un site distinct de celui impliqué dans la fixation des neurotrophines. La sélection de mutants viraux résistants à la neutralisation par une forme soluble de p75 a permis d'identifier les résidus F318 et H352 de la glycoprotéine virale comme nécessaire à la fixation de p75. Ces résidus localisés en dehors des sites antigénique s, ne modifient pas la structure antigénique de la protéine. Nous avons alors caractérisé la pathogénie et la propagation de ces mutants, parallèlement à l'étude de souris transgénique p75-/-. Nous avons montré que p75 n'est pas nécessaire à l'entrée du virus lors des expériences réalisées en animal, mais semble associé à un contrôle de l'infection
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Deshpande, Sachin S. [Verfasser], and Christian [Akademischer Betreuer] Schachtrup. "The role of the p75 neurotrophin receptor (p75NTR) in adult neural stem/precursor cell properties after cortical injury." Freiburg : Universität, 2020. http://d-nb.info/1212361121/34.
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Yu, Lingli. "Nerve Growth Factor Signaling from Membrane Microdomain to Nucleus : Differential Regulation by Caveolins." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2012. http://tel.archives-ouvertes.fr/tel-00796393.
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At the plasma membrane, both NGF receptors have been shown to localized to lipid rafts, specific subdomains that are enriched in cholesterol, sphingolipids and the presence of caveolin proteins (Cav1 and/or Cav2). The focus of this work is on this membrane microenvironment mediated modulation of NGF signaling which via two receptors: p75NTR and TrkA. In the present work we found that overexpression of Cav-1 in mouse dorsal root ganglia neurons significantly impacted neurite extension. Similarly, overexpression of Cav-1 in PC12 cells strongly inhibits their ability to grow neurites in response to NGF. It inhibits NGF signaling without, impairing transient MAPK pathway activation. Rather, it does so by sequestering NGF receptors in lipid rafts, which correlates with the cell surface localization of downstream effectors, and phosphorylated-Rsk2, resulting in the prevention of the phosphorylation of CREB. By contrast, overexpression of Cav-2 potentiates NGF induced differentiation, which is accompanied by sustained activation of downstream effectors, and standard internalization of the receptors. This differential effect could be due to the different localization of Caveolins, that modifies the microenvironment, thereby affecting NGF signaling. Furthermore, PC12 cells expressing the non-phosphorylatable Cav-1 mutant (S80V), neither TrkA trafficking or CREB phosphorylation are inhibited and the response resembles that observed in Cav-2 expressing PC12 cells. These studies underline the interplay between caveolins and NGF signalling, offering insight into the potential impact of Caveolin-1 and mutations thereof in certain cancers where NGF signaling is involved.
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DE, PERINI ALESSANDRA. "NGF e regolazione del sistema muscolare: effetto sul differenziamento e sulla sopravvivenza delle cellule miogeniche." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/509.
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Utilizzando un modello in vitro, la linea di mioblasti di ratto L6C5, ci siamo interessati di analizzare il ruolo del fattore di crescita neuronale, NGF, sulla crescita, differenziamento e sopravvivenza cellulare in seguito a stimolo apoptotico indotto da dosi citotossiche di perossido d’idrogeno. Mioblasti e/o miotubi L6C5 sono stati coltivati in condizioni standard o in presenza di differenti concentrazioni di NGF (20-100ng/ml), raccolti a diversi tempi durante il corso del differenziamento e analizzati per: a) crescita e sopravvivenza cellulare (saggio MTS, apoptosi); b) espressione di alcuni marcatori specifici del differenziamento (miogenina e MHC); c) tasso di fusione dei mioblasti (immunocitochimica); d) attivazione della via di trasduzione del segnale (NFkB, AKT). Riguardo l’influenza che il fattore neurotrofico può avere sulla crescita cellulare, abbiamo verificato che NGF è in grado di sostenere la crescita dei mioblasti L6C5 anche se vengono coltivati in terreno privo di siero, ma non è in grado di modificare sostanzialmente il potenziale proliferativo di queste cellule. Per quanto riguarda gli effetti sul differenziamento abbiamo dimostrato che la presenza di NGF (20 ng/ml) induce una sovra-espressione di miogenina nelle prime fasi di differenziamento (2 giorni in DM), con conseguente ipertrofia delle fibre che, in presenza di NGF, mostrano un indice di fusione maggiore. Analogamente alla miogenina, NGF modula l’espressione di NFkB solo durante la prima fase del processo differenziativo (2 giorni in DM), e l’incremento di attività di questo fattore di trascrizione è possibilmente correlata con una minore sensibilità all’apoptosi indotta da H2O2 in una fase più avanzata del differenziamento (6 giorni).
Sui mioblasti L6C5 mantenuti in terreno proliferativo (GM), NGF migliora la sopravvivenza a dosi citototossiche di perossido d’idrogeno, senza però mostrare differenze riguardo l’attivazione di NFkB e, di conseguenza, nella suscettibilità all’apoptosi. Abbiamo verificato poi che l’inibizione di p75NTR, l’unico recettore ad essere espresso in queste cellule, non comporta un aumento nella percentuale di nuclei apoptotici, suggerendo che la via di trasduzione attivata da tale recettore non può essere il processo maggiormente coinvolto nell’attivazione del processo apoptotico nei mioblasti L6C5. Sebbene l’analisi per RT-PCR non dimostri la presenza nelle cellule L6C5 di mRNA per TrkA, la nostra linea cellulare mostra chiaramente una particolare sensibilità al AG879, un inibitore specifico per alcuni recettori tirosin chinasici, compreso TrkA, VEGFR e EGFR. La presenza di AG879 in coltura determina una riduzione drastica della sopravvivenza cellulare, una riduzione nella fosforilazione di AKT e la proteolisi apoptotica dell’enzima poli (ADP ribosio) polimerasi (PARP).Our study is focused on the importance that NGF could have in the molecular mechanisms that regulate the muscular system analyzing its effective role on growth, survival and differentiation of myogenic cells. We performed an in vitro protocol utilizing L6C5 rat skeletal myoblasts, already characterized by our group. L6C5 myoblasts and myotubes were exposed to different concentrations of exogenous NGF (20ng/ml) and were then collected at different time during differentiation to be analyzed for cell growth and survival (MTS assay) the expression of specific myogenic markers (Myogenin and MHC), fusion rate (immunocytoquimical analysis), NFkB activation (Elisa assay), and induction of apoptosis (nuclear fragmentation, Tunel). Studying the influence of the neurotrophic factor on cell growth, we verified that NGF is able to sustain myoblast survival in FBS-free medium, but it cannot induce changes in the rate of cell growth. As regards the effective role on differentiation we demonstrated that NGF (20ng/ml) determines an increase in the differentiative potential of this cell line inducing an over-expression of myogenin in the first phases of the process (2 days in DM), with a consequent hypertrophy of fibers due to an increase in the fusion rate. On the contrary the MHC expression, a terminal differentiation marker, seems not be modulated by NGF. At the same differentiation step (2 days from DM), we found that NGF (20ng/ml) modulates the activity of NFkB, possibly leading to decrease of L6C5 cell susceptibility to apoptosis induced by oxidative stress. When L6C5 myoblasts were maintained in the proliferation medium (GM), NGF can improve the L6C5 myoblast survival towards oxidative stress, but without modifying their susceptibility to apoptosis, or the binding activity of NFkB. Since the p75 low affinity receptor resulted the only one expressed in L6C5 myoblasts and myotubes, we blocked its endogenous action trough an anti-p75 mAb, but this inhibition did not cause a significant increase of apoptotic nuclei, suggesting that the transduction pathway activated by p75 is not the main process involved in the susceptibility of L6C5 myoblasts to apoptotic death. Indeed, although L6C5 cells did not express TrkA receptor, our cellular model is sensitive to treatments with a specific TRK receptor’s inhibitor (AG879), which caused a significant decrease in cell survival together with a reduction in Akt phosphorylation and apoptotic proteolysis of poli (ADP ribose) polymerase enzyme (PARP).
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Lara, Pedro Túlio de Resende. "Análise estrutural do fator de crescimento neural e as implicações moleculares de suas mutações na interação com os receptores TRKA e P75NTR." reponame:Repositório Institucional da UFABC, 2015.
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Orientador: Prof. Dr. Antônio Sérgio Kimus BrazDissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Biossistemas, 2015.
O NGF (fator de crescimento neural) é uma proteína endógena secretada no sistema nervoso central e periférico, desempenhando diversos papéis, tais como neuroproteção, desenvolvimento e diferenciação neuronal, crescimento de neuritos e plasticidade sináptica. Sintetizado no neocórtex e no hipocampo, o NGF atua em populações de neurônios colinérgicos, sensoriais e simpáticos através da interação com receptores TrkA e p75NTR. Está relacionado com neuropatologias como doença de Alzheimer, hiperalgesia e com as neuropatologias autonômicas e sensoriais hereditárias tipos IV e V, onde foram identificas as mutações S187N e R221W, respectivamente. Apesar do vasto conhecimento da ação das vias relacionadas ao NGF e seus receptores, os mecanismos moleculares de interação, bem como da ativação das sinalizações internas dos receptores, ainda não estão totalmente esclarecidos. Através da abordagem de análise de modos normais, foram investigadas as alterações estruturais dos mutantes em relação ao tipo selvagem de NGF sob a ótica de estrutura de proteínas. Diferenças significativas na correlação de movimentos globais, flexibilidade do complexo, interações moleculares e na liberdade conformacional em ambas as mutações foram encontradas. Foram observadas variações estruturais e limitações conformacionais nos receptores como reflexo da ação dos mutantes de NGF, indicando que, mesmo após a interação, neurotrofina e receptor formam um complexo ativo. Desse modo, as mutações no NGF reduzem a capacidade de formação do complexo ativado através de alterações estruturais e conformacionais, causando prejuízo às funções biológicas derivadas da interação.
NGF (nerve growth factor) is an endogenous protein secreted in the central and peripheral nervous system, playing different roles, such as neuroprotection, development and neuronal differentiation, neurite outgrowth and synaptic plasticity. Synthesized in the neocortex and hippocampus, NGF acts on populations of cholinergic, sensory and sympathetic neurons through interaction with TrkA and p75NTR receptors. It is related neuropathologies such as Alzheimer's disease, hyperalgesia and hereditary sensory and autonomic neuropathologies types IV and V, which were identified the mutations S187N and R221W, respectively. Despite the vast knowledge of the action of pathways related to NGF and its receptors, the molecular mechanisms of interaction as well as the activation of the internal signalling pathways of the receptors are still not fully understood. Through the normal modes analysis approach, the structural changes of the mutants compared to wild type NGF were investigated from the perspective of protein structure. Significant changes in global movements correlation, complex flexibility, molecular interactions and conformational freedom were found for both mutations. Structural changes and conformational limitations in the receptors were observed, as reflecting the action of NGF mutants, indicating that even after the interaction neurotrophin and receptor form an active complex. Thus, mutations in the NGF reduce the ability of activated complex formation by structural and conformational changes, causing impairment to biological functions derived from the interaction.
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Kichev, Anton Vladimirov. "Implication of pro-NGF in the neurodegeneration: characterization of the underlying physiological mechanisms in Alzheimer´s Disease." Doctoral thesis, Universitat de Lleida, 2008. http://hdl.handle.net/10803/8094.
Full textAbstract:
El presente trabajo está centrado en la posible relación entre la formprecursora del Factor de Crecimiento de Neuronas (pro-NGF) y la muerte
celular inducida durante el patogénesis de la Enfermedad de Alzheimer (EA).
Hemos estudiado el efecto fisiológico de pro-NGF aislado de cerebro
humano, utilizando diversos modelos celulares expresores de p75NTR. En
presencia de pro-NGF aislado de cerebro afectado por EA (hbi-pro-NGF) se
observa una fuerte inducción de apoptosis. El pro-NGF aislado de cerebros
humanos control no es capaz de inducir muerte celular en los modelos
estudiados.
P75 NTR esta descrito como receptor especifico para pro-NGF.
Hemos observado niveles aumentados de su producto de procesamiento p75
ICD en tejido de cerebro afectado de EA.
En los modelos celulares estudiados, la inducción de apoptosis es
posterior al procesamiento de p75NTR con liberación de su dominio intracelular
(ICD). La liberación de p75NTR ICD depende de γ-Secretasa. La actividad de
γ-Secretasa es imprescindible para la inducción de apoptosis. El fragmento ICD
liberado se transloca hacia el núcleo. Hbi-pro-NGF aislado de cerebro control
no es capaz de inducir procesamiento de p75NTR, ni translocación de su ICD.
Los niveles de modificaciones post-tranductionales no enzimáticos de
pro-NGF en hippocampo y en cortex entorhinal, se muestran aumentados en
los cerebros humanos afectados por EA.
Pro-NGF modificado in vitro por glyoxal y methylglyoxal demuestra una
aumentada resistencia al procesamiento por furina y por consíguente una
capacidad más elevada de inducir muerte celular por p75NTR. Ratones
inyectados en ventrículo cerebral con este pro-NGF modificado presentan
dificultades significativas en procesos de aprendizaje comparados con los
ratones inyectados con pro-NGF no modificado y con ratones inyectados con
BSA modificado de misma manera.
Los resultados descritos hasta ahora abren una posible vía de
interpretación de los efectos de pro-NGF en cerebro humano durante desarrollo
de EA pudiendo ser causantes de neurodegeneración a través de una via
dependiente de γ-Secretasa y activación de p75NTR.
The aim of the present work is to investigate a possible relationship
between the pro-form of the Neurotrophic Growth Factor (pro-NGF) and the cell
death induced during pathogenesis of Alzheimer Disease (AD).
We studied the physiological effect of pro-NGF isolated from human
brain (hbi-pro-NGF) in different cell models that express p75NTR. We show that
hbi-pro-NGF is a potent pro-apoptotic agent. Interestingly, the hbi-pro-NGF
isolated from control human brain was shown to be unable to induce cell death
in the used models.
The specific receptor of pro-NGF was described to be p75NTR. We
describe that higher amounts of its processing products - p75NTR ICD, are
observed in brain tissue affected from AD.
In the cellular models that we used, the induction of apoptosis was
preceded by processing of p75NTR with liberation of its ICD. p75NTR
processing is γ-Secretase dependent. The induction of pro-apoptotic effect was
shown to be entirely dependent of γ-Secretase activity. Released p75NTR ICD
is shown to be translocated to nuclei. Hbi-pro-NGF isolated from control brain is
not able to induce processing of p75NTR neither translocation of its ICD.
The levels of non enzymatic post-translational modifications of pro-NGF
in the hippocampus and enthorinal cortex increase in AD affected brains. This
can explain the greater stability and elevated physiological activity of pro-NGF
isolated from human brains affected with AD.
The in vitro modified pro-NGF by glyoxal and methylglyoxal shows
greater resistance against the furine cleavage and consequently greater ability
to induce cell death trough p75NTR. Mice intracerebroventricularly injected with
this modified rh-pro-NGF present significant learning difficulties compared with
controls intracerebroventricularly injected with non modified pro-NGF and even
greater differences compared with modified BSA.
The results that we describe suggest the possibility that highest levels of
non enzymatic modifications of pro-NGF in human brain during the progress of
AD could lead to neuron loss by a γ-Secretase dependent activation of
p75NTR.
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Wang, Yan-Jiang, and yanjiang_wang@tmmu edu cn. "Clearance of amyloid-beta in Alzheimer's disease: To understand the pathogenesis and develop potential therapies in animal models." Flinders University. School of Medicine, 2010. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20100419.124325.
Full textAbstract:
Alzheimer's disease (AD) is the most common cause of dementia. No strong disease-modifying treatments are currently available. Amyloid-beta peptide (Abeta) appears to play a pivotal role in the pathogenesis of AD. We focused our interest on revealing the pathogenesis of the disease and developing novel therapeutic modalities. The thesis consists of three projects:
1. Prevention of AD by intramuscular delivery of an anti-Abeta single chain antibody (scFv) gene:
Immunotherapy is effective in removing brain Abetazbut was associated with detrimental effects. In the present study, the gene of an anti-Abeta scFv was delivered in the hind leg muscles of APPSwe/PS1dE9 mice with adeno-associated virus at three months of age. Six months later, we found that brain Abeta accumulation, AD-type pathologies and cognitive impairment were significantly attenuated in scFv-treated mice relative to enhanced green fluorescence protein (EGFP)-treated mice. Intramuscular delivery of scFv gene was well tolerated by the animals. These findings suggest that peripheral application of scFv is effective and safe in preventing the development of AD, and would be a promising non-inflammatory immunological modality for prevention and treatment of AD.
2. Prevention of AD with grape seed derived polyphenols: Polyphenols extracted from grape seeds are able to inhibit Abetanaggregation, reduce Abeta production and protect against Abeta neurotoxicity in vitro. We investigated the therapeutic effects of a polyphenol-rich grape seed extract (GSE) in vivo. APPSwe/PS1dE9 transgenic mice were fed with normal AIN-93G diet (control diet), AIN-93G diet with 0.07% curcumin, or diet with 2% GSE beginning at 3 months of age for 9 months. Total phenolic content of GSE was 592.5 mg/g dry weight, including gallic acid, catechin, epicatechin and proanthocyanidins. Long-term feeding of GSE diet was well tolerated. The Abetanlevels in the brain and serum of the mice fed with GSE were reduced by 33% and 44% respectively compared with the mice fed with the control diet. Amyloid plaques and microgliosis in the brain of mice fed with GSE were also reduced by 49% and 70% respectively. In conclusion, polyphenol-rich GSE is promising to be a safe and effective drug to prevent the development of AD.
3. Roles of p75NTR in the development of AD: P75NTR has been suggested to mediate Abeta induced neurotoxicity. However, its role in the development of AD is undetermined. APPSwe/PS1dE9 transgenic mice were crossed with p75NTR knockout mice to generate APPSwe/PS1dE9 mice with p75NTR gene deleted. P75NTR mainly expressed in the basal forebrain neurons and degenerative neurites in neocortex and hippocampus. Genetic deletion of p75NTR gene in APPSwe/PS1dE9 mice reduced soluble Abeta levels, but increased the insoluble Abeta accumulation and Abeta plaque formation in the brain. P75NTR deletion decreased Abeta production of cortical neurons in vitro. Recombinant extracellular domain of p75NTR attenuated the oligomerization and fibrillation of synthetic Abeta42 peptide in vitro, and reduced local Abeta plaques after hippocampus injection in vivo. Our data suggest that p75NTR plays an important role in AD development and may be a valid therapeutic target for the treatment of AD.
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Pentek, Falk [Verfasser], Johannes H. [Akademischer Betreuer] Schulte, and Ludger [Akademischer Betreuer] Klein-Hitpaß. "Der niedrigaffine Neurotrophinrezeptor p75NTR reduziert die Tumorigenität des Neuroblastoms in vitro und in vivo / Falk Pentek. Gutachter: Ludger Klein-Hitpaß. Betreuer: Johannes H. Schulte." Duisburg, 2013. http://d-nb.info/1045839396/34.
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Calderón, Jofre Rodrigo Fernando. "El péptido A[beta] en concentraciones nanomolares es capaz de modular la actividad del R-NMDA en la DPS por interacción con el receptor p75NTR." Tesis, Universidad de Chile, 2009. http://www.repositorio.uchile.cl/handle/2250/111638.
Full textAbstract:
Memoria para optar al Título de BioquímicoLa enfermedad de Alzheimer (EA) es una patología neurodegenerativa progresiva caracterizada principalmente por agregados proteicos intracelulares (ovillos neurofibrilares) y extracelulares (placas seniles o amiloides). Estos últimos están formados por un péptido de 39 a 43 aminoácidos, conocido como péptido ß amiloide (Aß), el que se genera por proteólisis de la Proteína Precursora del Amiloide (APP). Existen dos formas principales del péptido Aß, una de 40 aminoácidos presente en personas sanas, y otra de 42 aminoácidos, constituyente principal de las placas observadas en pacientes de EA. Estas placas se forman a partir de la agregación de monómeros (M) que forman oligómeros solubles (O), los que formarían posteriormente protofibrillas y finalmente las fibras insolubles. La falta de correlación entre el grado de demencia y la cantidad de placas ha sugerido que los oligómeros solubles podrían ser los responsables de los síntomas iniciales. Si bien no están claros los blancos específicos del péptido Aß, uno de los principales candidatos son las sinapsis excitatorias que responden a glutamato. Estas sinapsis poseen una especialización de membrana conocida como densidad postsináptica (DPS), estructura que contiene a los receptores para neurotransmisores y proteínas asociadas a la regulación de la función sináptica, agrupadas por proteínas de andamio. Dentro de los receptores para glutamato, el R-NMDA es de gran importancia en procesos de memoria y aprendizaje, y su actividad puede ser modulada por el receptor para neurotrofinas p75NTR. Este receptor también está contenido en la DPS, y participa tanto en sobrevida como en apoptosis neuronal. Además, posee la capacidad de unirse a ligandos estructuralmente no relacionados, entre los que se encuentra el péptido Aß, postulándose como potencial blanco molecular del péptido. Nuestra hipótesis es que El péptido Aß en concentraciones nanomolares es capaz de inhibir la actividad del R-NMDA en la DPS por interacción con el receptor p75NTR. Para este trabajo, se obtuvieron DPS de corteza de rata adulta, las cuales fueron microinyectadas en ovocitos de Xenopus laevis. Estos ovocitos son sometidos a estudios de fijación de potencial con 2 electrodos (voltage clamp), y se midieron las respuestas obtenidas con el agonista NMDA en presencia de distintas concentraciones del péptido Aß1-40(M) y Aß1-42(M) y (O). En el caso del péptido Aß1-42(M), se observa una inhibición a todas las concentraciones utilizadas, sin ser dependiente de la dosis. Por otro lado, los péptidos Aß1-40(M) y Aß1-42(O) poseen efectos duales sobre las corrientes de NMDA: a bajas concentraciones producen un efecto inhibitorio y a altas concentraciones un efecto potenciador. En el caso del péptido Aß1-40(M), la inhibición se logra usando una concentración de 50 nM, mientras que en el caso del Aß1-42(O) se logra con una concentración de 5 nM. En ambos casos la potenciación ocurre al usar una concentración de 1 uM. Adicionalmente, el efecto Aß1-42(O) está mediado por el receptor p75NTR, ya que el uso de un anticuerpo que produce pérdida de función del receptor es capaz de revertir tanto el efecto inhibidor como potenciador del péptido. Estos datos permiten confirmar que existe participación del receptor p75NTR en los efectos sinápticos causados por el péptido, especialmente sobre la actividad del RNMDA, apuntando al rol fisiológico del péptido y su relación con la patología de la EA.
Alzheimer’s disease (AD) is a neurodegenerative progressive pathology characterized mainly by protein intracellular (neurofibrillary tangles) and extracellular (Amyloid plaques) aggregates. The latter are formed by 39-43 aminoacids peptide, known as amyloid ß(Aß), generated by proteolysis of Amyloid Precursor Protein (APP). There are two principal forms, one of 40 aminoacids, present in healthy people, and other of 42 aminoacids, main constituent of plaques seen in AD patients. These plaques are formed by aggregation of monomers (M), which form oligomers (O), then protofibrils and finally insoluble fiber. The lack of correlation between grade of dementia and number of plaques has suggested that soluble oligomers could be the responsible of initial symptoms. Although there is no clarity about specific targets of Aß peptide, one of the most named are excitatory synapses activated by glutamate. These synapses have a membrane specialization known as postsynaptic density (PSD), structure that contains the neurotransmitter receptors and proteins associated with regulation of synaptic function, grouped by scaffolding proteins. Between glutamate receptors, NMDA-R has great importance in memory and learning process, and his activity can be modulated by the neurotrophin receptor p75NTR. This receptor is also present in PSD and participates in both survival and neuronal apoptosis. In addition, it has the ability to bind ligands structurally unrelated, including Aß peptide, postulating the p75NTR as a potential molecular target of the peptide. Our hypothesis is that Aß peptide in nanomolar concentration is able to inhibit R-NMDA activity in PSD by interacting with p75NTR. For this work, we obtained PSD from adult rat cortex, which were microinjected into Xenopus laevis oocytes. These oocytes were subjected to 2-electrodes voltage clamp, and responses to agonist NMDA were acquired in presence of different concentrations of Aß1-40(M) and Aß1-42(M) and (O). In the case of Aß1-42(M), inhibition was non dose-dependent. On the other hand, Aß1-40(M) and Aß1-42(O) have dual effect on NMDA-R currents: at low concentrations the peptides have an inhibitory effect and at high concentrations a potentiation effect. In the case of Aß1-40(M), inhibition is obtained using a concentration of 50 nM, whereas for the Aß1-42(O) is obtained with a concentration of 5 nM. In both cases, potentiation occurs when a concentration of 1 uM is used. Additionally, the effect of Aß1-42(O) is p75NTR-mediated, because the use of loss-of-function antibody reversed both inhibition and potentiation effect. These data allow us to confirm that there is participation of p75NTR in synaptic effects caused by Aß peptide, specially on NMDA-R activity, pointing to the physiological function of the peptide and its relationship with AD pathology.
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Kegler, Pangrazio Kristel [Verfasser]. "In vitro and in vivo characterization of p75NTR-expressing glia and investigations upon their origin in the canine central nervous system[[Elektronische Ressource]] / Kristel Kegler Pangrazio." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2015. http://d-nb.info/1073881504/34.
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Sissoëff, Ludmilla. "Caractérisation d'une forme recombinante, soluble et trimérique, de la glycoprotéine G du virus de la rage et application à l'étude de voies de signalisation dépendantes de p75NTR." Paris 11, 2005. http://www.theses.fr/2005PA114810.
Full textAbstract:
La glycoprotéine G (G) est l'unique glycoprotéine du virus de la rage ; elle forme des spicules trimériques à la surface du virus. C'est un nouveau ligand pour p75NTR, récepteur des neurotrophines, dont l'ectodomaine est composé de quatre domaines riches en cystéine (DRC). Nous avons tout d'abord montré que la trimérisation stable de l'ectodomaine de G est nécessaire à son interaction avec p75NTR (l'ectodomaine de G formant des trimères instables qui se dissocient en monomères). La construction d'une protéine G recombinante composée de l'ectodomaine, fusionné à un motif de trimérisation, «le foldon» de la fibritine du phage T4, a permis de stabiliser G sous une forme trimérique. Cette protéine adopte une conformation antigénique similaire à la G native au niveau carboxy-terminal et interagit avec p75NTR avec une forte affinité. Nous avons ensuite exprimé un domaine suffisant de G capable d'interagir avec p75NTR. Une méthode de purification partielle de G conservant sa fonctionnalité a été mise au point. Enfin, nous avons abordé l'influence de G sur des voies de signalisation dépendantes de p75NTR et impliquées dans la croissance neuronales. Nous avons montré que G, en se fixant sur la DRC1, favorise l'interaction entre p75NTR et NgR, entraînant une activation de Rhoa qui conduit vraisemblablement à l'ihnibition de régénération axonale. Le DRC1 de p75NTR semble un rôle modulateur dans l'interactiçon avec NgR. D'autre part, en favorisant l'interaction entre p75NTR et Necdin, G semble accélerer la différenciation des cellules PC12Necdin comme le NGF.
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MOSCATELLI, ILANA. "Effects of culture conditions on proliferation and self-renewal of murine embryonic stem cells: growth factors and 3D substrates." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2009. http://hdl.handle.net/2108/866.
Full textAbstract:
La regolazione del destino delle cellule staminali embrionali (ES) è controllata da una fitta rete di segnali che ne promuovono il rinnovamento o al contrario ne inducono il differenziamento. Per studiare meccanismi che regolano questi eventi ci siamo focalizzati su due diversi aspetti delle condizioni colturali: l’aggiunta di fattori di crescita al terreno di coltura e l’utilizzazione di un substrato tri-dimensionale per mimare la matrice extracellulare prodotta dal feeder-layer di fibroblasti embrionali mitoticamente inattivati, che è solitamente presente nella coltura delle cellule ES. Abbiamo dimostrato che l’aggiunta di NGF al terreno di coltura stimola la proliferazione e il rinnovamento delle cellule ES; analogamente, in assenza di un feeder-layer, uno scaffold 3D di policaprolattone può contribuire a prevenire il differenziamento delle cellule ES. Queste osservazioni possono fornire informazioni utili per una migliore comprensione del ruolo che i molteplici componenti presenti nel microambiente delle cellule staminali svolgono nel regolarne l’evoluzione.The regulation of embryonic stem (ES) cell fate is controlled by the interplay of signalling networks that either promote self-renewal or induce differentiation. To study the factors that have an effect on these mechanisms we have focused on two different aspects of culture conditions: the addition of growth factors to the culture medium, and the utilization of a three-dimensional substrate to mimic the extracellular matrix produced by the feeder-layer of mitotically inactivated embryonic fibroblasts, usually present in embryonic stem cell culture. We demonstrated that NGF addition to the culture medium stimulates ES cells proliferation with self-renewal and, similarly, in the absence of a cell feeder layer, a 3D polycaprolactone scaffold helps preventing ES cell differentiation. These observations may provide useful information for a better comprehension of the multiple components of the stem cell niche.
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PIERANTOZZI, ENRICO. "Isolamento e caratterizzazione di sottopopolazioni ES-simili dal sangue di cordone ombelicale e periferico umani e dal midollo osseo murino." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2006. http://hdl.handle.net/2108/208313.
Full textAbstract:
During the last few years much progress has been made in the knowledge of adult and embryonic stem cell biological properties. The ability to isolate and culture in conditions that allow the expansion of these cells without their losing stem potential, has helped in using stem cells as a tool to treat patients suffering from certain cellular degenerative diseases or affected with a specific cellular population loss of functionality. Because of their wide potentialities, embryonic stem cells (ES) obtained from blastocyst inner cell mass, appear to have the best chance as a tool to treat degenerative diseases affecting tissues of different embryonic origin. Biological difficulties (such as the risk of uncontrolled proliferation, graft versus host disease, the need to set culture conditions free of non-human compounds) and, above all, legal and ethical problems, seem to prevent the therapeutic application of such cells. The identification and characterization of an ES-like cell population in adult tissues might be of great help to exploit these cells in the medical field. In this thesis I show that a cellular population featuring certain molecular ES cell properties, may be isolated from human cord blood after depletion of all differentiated cells but monocytes, followed by the positive selection of cells bearing p75 neurotrophin receptor (p75NTR). Cytofluorimetric assays revealed that a fraction of p75NTR+ cells express SSEA3 and SSEA4, two typical human ES cell glycolipidic markers. Real Time RT-PCR assays showed that, following the selection for p75NTR+, a cell population is obtained that expresses very high levels of Oct4 and Nanog, two transcription factors whose importance in ES stemness and self-renewal is largely documented. Further increase of Oct4 and Nanog expression level is obtained following depletion of cells bearing Mac-1, a typical monocytes marker. A similar study has been made in human peripheral blood and mouse bone marrow. Data obtained by Real Time RT-PCR assays, have shown that in two out of four samples of adult peripheral blood analysed by the above selection method, following isolation of p75NTR+ cells, a cell population expressing high levels of Oct4 and Nanog was obtained. In 4-5 weeks-old mouse bone marrow, the highest expression of Oct4 and Nanog has been detected in p75NTR+/Mac-1- cells, while, in older mice (13-14 weeks), such expression increase has been detected in p75NTR+/Mac-1+ cells.
Further studies are needed to evaluate whether these cells, in addition to bearing ES cell molecular markers, also have functional ES-like properties and can be classified as true ES-like cells
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Ersözlü, Sara [Verfasser]. "Effects of pre- and postnatal deletion of the transcription factor Nkx2-1 on the expression of NGF, trkA, trkB and p75NTR in mice and a clinical update on NKX2-1 haploinsufficiency in humans / Sara Ersözlü." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2021. http://d-nb.info/1234985268/34.
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Susen, Kathrin. "Untersuchungen zur Signaltransduktion des ss-Amyloids [Beta-Amyloids] über den p75LNTR." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965229599.
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Erck, Christian. "Molekularbiologische Untersuchungen der Funktion und Regulation des Neurotrophin-Rezeptors p75NGFR in Muskelzellen." [S.l.] : [s.n.], 1998. http://deposit.ddb.de/cgi-bin/dokserv?idn=954864085.
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Blake, Judith A. "The characterisation of Pax3 expressant cells in adult peripheral nerve." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2011. https://ro.ecu.edu.au/theses/448.
Full textAbstract:
Pax3 has numerous integral functions in embryonic tissue morphogenesis while knowledge of its complex function in cells of adult tissue continues to unfold. Across a variety of adult tissue lineages, the role of Pax3 is principally linked to maintenance of the tissue’s resident stem and progenitor cell population. In adult peripheral nerves, Pax3 is reported to be expressed in nonmyelinating Schwann cells, however, little is known about the purpose of this expression. Based on the evidence of its role in other adult tissue stem and progenitor cell maintenance, it was hypothesised that the cells in adult peripheral nerve that express Pax3 may be Schwann glioblasts. Here, methods have been developed for visualisation of Pax3 expressant cells in normal 60 day old mouse peripheral nerve. Visualisation allowed morphological, anatomical and phenotypic distinctions to be made between these Pax3 expressing cells and Remak bundle nonmyelinating Schwann cells. The distinctions described herein, together with the finding that Pax3 expressing cells co-express stem cell marker Sox2, provides compelling support for the suggestion that a progenitor Schwann cell population may be present in adult mouse peripheral nerve.
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Kaut, Oliver. "Expression von TNF[alpha] [TNF-alpha] und seinen Rezeptoren p55TNFR und p75TNFR im Gehirn der Maus nach SEB- und LPS-Stimulation." [S.l.] : [s.n.], 2005. http://archiv.ub.uni-marburg.de/diss/z2005/0115/.
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Guidi, Mònica. "Micro RNA-Mediated regulation of the full-length and truncated isoforms of human neurotrophic tyrosine kinase receptor type 3 (NTRK 3)." Doctoral thesis, Universitat Pompeu Fabra, 2009. http://hdl.handle.net/10803/7114.
Full textAbstract:
Neurotrophins and their receptors are key molecules in the development of thenervous system. Neurotrophin-3 binds preferentially to its high-affinity receptor
NTRK3, which exists in two major isoforms in humans, the full-length kinaseactive
form (150 kDa) and a truncated non-catalytic form (50 kDa). The two
variants show different 3'UTR regions, indicating that they might be differentially
regulated at the post-transcriptional level. In this work we explore how
microRNAs take part in the regulation of full-length and truncated NTRK3,
demonstrating that the two isoforms are targeted by different sets of microRNAs.
We analyze the physiological consequences of the overexpression of some of the
regulating microRNAs in human neuroblastoma cells. Finally, we provide
preliminary evidence for a possible involvement of miR-124 - a microRNA with no
putative target site in either NTRK3 isoform - in the control of the alternative
spicing of NTRK3 through the downregulation of the splicing repressor PTBP1.
Las neurotrofinas y sus receptores constituyen una familia de factores cruciales
para el desarrollo del sistema nervioso. La neurotrofina 3 ejerce su función
principalmente a través de una unión de gran afinidad al receptor NTRK3, del cual
se conocen dos isoformas principales, una larga de 150KDa con actividad de tipo
tirosina kinasa y una truncada de 50KDa sin dicha actividad. Estas dos isoformas
no comparten la misma región 3'UTR, lo que sugiere la existencia de una
regulación postranscripcional diferente. En el presente trabajo se ha explorado
como los microRNAs intervienen en la regulación de NTRK3, demostrando que las
dos isoformas son reguladas por diferentes miRNAs. Se han analizado las
consecuencias fisiológicas de la sobrexpresión de dichos microRNAs utilizando
células de neuroblastoma. Finalmente, se ha estudiado la posible implicación del
microRNA miR-124 en el control del splicing alternativo de NTRK3 a través de la
regulación de represor de splicing PTBP1.
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Schweigreiter, Rüdiger [Verfasser]. "Untersuchungen über die funktionelle Rolle des Neurotrophinrezeptors p75NTR / Rüdiger Schweigreiter." 2002. http://d-nb.info/967274273/34.
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Hucho, Tim [Verfasser]. "Der Neurotrophinrezeptor p75NTR : eine biochemische Untersuchung / vorgelegt von Tim Hucho." 2002. http://d-nb.info/964999757/34.
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Smithson, LAURA. "The morphology, neurochemistry, and consequences of sympathosensory plexuses." Thesis, 2013. http://hdl.handle.net/1974/8122.
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The development, maintenance, and survival of neurons depend on the function of neurotrophins such as nerve growth factor (NGF). One population of neurons that rely heavily on NGF for axonal growth and survival is the postganglionic sympathetic neurons. Trauma or disease resulting in injury to the peripheral nervous system causes an increase in the levels of this neurotrophin. This augmentation promotes the collateral sprouting of postganglionic sympathetic axons into those tissues having elevated levels of NGF. Often, NGF-induced sympathetic sprouting occurs in tissues that are normally innervated by these fibers however, high levels of NGF can also promote sprouting of axons into tissues that are normally devoid of sympathetic fibers, such as the sensory ganglia. When postganglionic sympathetic axons grow into the environment of sensory ganglia, they can converge and wrap around a subset of somata (i.e., cell bodies) belonging to primary sensory neurons. This phenomenon, referred to as sympathosensory plexuses is observed in adult mice and rats following peripheral nerve injury, and is also seen in adult transgenic mice that ectopically over express NGF.
The overall aim for this project is to examine the morphological and neurochemical features, as well as the overall consequence of sympathosensory plexuses in nerve-injured adult mice and in adult transgenic mice that over express NGF. We hope that this novel information will add to our understanding of the underlying mechanisms associated with the formation of sympathosensory plexuses that occur following injury.Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2013-07-23 18:51:47.902
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Lin, Li-Hsuan, and 林立軒. "Role of p75NTR in Neurovascular Unit with Oxygen-glucose Deprivation/Reperfusion Injury." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/p2gc9q.
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碩士國立陽明大學
解剖學及細胞生物學研究所
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Stroke has been a leading cause of death in the worldwide. Because of the angiopathy, the interruption of blood flow result in the deprivation of both oxygen and glucose to the regions of brain tissue. Ischemic stroke consists of two distinctive periods of pathological impact, ischemia and reperfusion. Ischemic phase results in a great proportion of neuronal cell death. Excitotoxicity, apoptosis and microglial activation are the mechanisms involve in neuronal cell death. Reperfusion phase has been linked to further stimulation of the inflammatory system which results in cytokines release (e.g. interleukin-1, tissue necrosis factor-α (TNFα)) and leukocyte recruitment, leading to more extensive injury. Injuries of reperfused tissue have also been shown to be related to excessive production of reactive oxygen species leading to endothelial tight junction proteins disruption and blood-brain barrier (BBB) hyperpermeability. BBB composed of neurovascular unit is a major target of ischemic-reperfusion injury. The BBB owes its enhanced protective function to the capillary endothelial cells. Its primary function is to act as a selective diffusion barrier at the level of the cerebral microvascular endothelium. This barrier provides the cells underlying BBB a protection, and the CNS homeostasis necessary for stable and coordinated neuronal activity is preserved. Nerve Growth Factor (NGF) regulates the differentiation, growth and survival of neurons in the CNS. There is a molecule with the ability to act as NGF receptor: p75 neurotrophin receptor (p75NTR). p75NTR plays an important role not only in the survival but also in the apoptosis in neurons according to its ligand binding to it. Although extensive research has devoted in the establishment of the role of p75NTR in neuronal cell death and axonal degeneration, the mechanisms underlying these conditions are still unclear. As we previously described, endothelial cells are the first one response to stimuli. No one mentioned the function of p75NTR in the endothelial cells. In our studies, we established an ischemic-reperfusion model showed the increase of FITC-dextran permeability and decrease in the expression of tight junction proteins. The protein expression of p75NTR was also upregulated after ischemic-reperfusion injury in the endothelial cells. We also used an antioxidant, Astaxanthin (AXT), which can cross BBB, to protect endothelial cells from oxidative stress. We found that AXT can reduce the protein expression of p75NTR and the apoptotic cells. AXT treatment decreased the permeability in our models, which paralleled with elevated expression of TJPs. These data demonstrate that p75NTR plays a role to modulate endothelial cell death via apoptosis following the injury and it may be a novel downstream target of AXT’s anti-apoptotic function.
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Krug, Marlon. "Auswirkung einer selektiven p75-Neurotrophinrezeptor-Defizienz im Immun- oder Zentralnervensystem auf die experimentelle autoimmune Enzephalomyelitis." Doctoral thesis, 2015. http://hdl.handle.net/11858/00-1735-0000-0022-5D9E-8.
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"The impact of reduced neuronal p75NTR expression on sensory neuron phenotype and associated glia." Thesis, 2011. http://hdl.handle.net/10388/ETD-2011-10-185.
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The common neurotrophin receptor, p75NTR, has been implicated in diverse responses of sensory neurons including a role in nociception following nerve injury, suggesting that it may serve a similar role in intact sensory neurons and their satellite glial cells (SGCs). To examine the impact of suppressing neuronal p75NTR expression on known molecular modulators/regulators of the nociceptive state namely, the sodium channels NaV1.8 and NaV1.9, the nerve growth factor receptor TrkA, the potassium channel Kir4.1, glial fibrillary acidic protein (GFAP), SGC p75NTR, connexin 43, we intrathecally infused p75NTR anti-sense oligonucleotides (AS OGN), previously shown by Obata et al. (2006) to effectively suppress p75NTR expression in intact neurons. Male, Wistar rats were divided into three groups, receiving either no treatment (non-infused), seven day intrathecal infusion of p75NTR AS OGN or sense control (SC OGN) via an osmotic pump. Serial L4 and L5 DRG sections were processed for immunohistochemistry to detect alterations in NaV1.8, NaV1.9, TrkA, Kir4.1, p75NTR, GFAP and connexin-43 protein expression. Sciatic nerve sections were also processed for immunohistochemistry to detect NaV1.8, NaV1.9, TrkA and GFAP protein expression.
Infusion of p75NTR AS OGNs resulted in a significant decrease in neuronal p75NTR expression, however no significant change was observed in neuronal NaV1.8, NaV1.9 or TrkA expression relative to SC OGN treated or non-infused controls. On the contrary, SGC expression of phenotypic markers normally associated with the reactive state that is induced in these cells in response to peripheral nerve axotomy was dramatically altered. More specifically, in response to p75NTR AS OGN infusion, there was a significant increase in SGC protein expression of the cytoskeletal protein GFAP and p75NTR, along with a significant decrease in expression of the inward rectifying potassium channel Kir4.1. Preliminary data also revealed this induced reactive state in SGCs to be associated with an increase in the number of SGCs surrounding individual neurons as well as increased SGC expression of the gap junction protein, connexin 43.
In conclusion, reductions in neuronal p75NTR expression and potentially reduced neurotrophin signaling lead to alterations in neuron/glial or axon/glial communication that results in induction of a reactive phenotype in the associated SGCs. With our ever increasing understanding of the role of SGCs modulating pain states, elucidation of the pathways leading to adoption of pathological phenotypes can help in the identification of novel therapeutic targets.
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Gschwendtner, Andreas [Verfasser]. "Regulation, zelluläre Lokalisation und Funktion des Neurotrophinrezeptors p75NTR bei der Regeneration von Motoneuronen / Andreas Gschwendtner." 2004. http://d-nb.info/972240187/34.
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Alves, Mariana Pires Antunes. "Genética do suicídio : investigação de SNPs em genes das neurotrofinas e mecanismos de transdução de sinal." Master's thesis, 2010. http://hdl.handle.net/10316/28718.
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Dissertação de mestrado em Biologia Celular e Molecular apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.O suicídio é um grave problema de saúde pública a nível mundial, principalmente em países industrializados, e os factores genéticos desempenham um papel importante na sua etiologia. As neurotrofinas desempenham funções importantes no sistema nervoso central e periférico, estando envolvidas, por exemplo, em processos de plasticidade sináptica. Algumas evidências sugerem que as neurotrofinas, particularmente o Brain-Derived Neurotrophic factor (BDNF) e o receptor pan-75 neurotrophin (p75NTR), poderão desempenhar um papel importante na etiologia do suicídio. Por exemplo, estudos postmortem realizados em vítimas de suicídio revelaram alterações nos níveis de expressão de BDNF e de p75NTR no hipocampo e no córtex pré-frontal. A proteína cinase G (PKG) pertence à família das cinases serina/treonina e desempenha funções ao nível da plasticidade sináptica e das vias de transdução de sinal, principalmente na activação de vias de sinalização em células pós-sinápticas, na mobilização de vesículas sinápticas na célula pré-sináptica e na libertação de neurotransmissores. Com base nestas evidências, colocámos a hipótese de que variantes genéticas no gene PRKG1 poderão eventualmente desempenhar um papel na susceptibilidade para o suicídio. Assim, neste projecto estudou-se o envolvimento dos SNPs Val66Met, S205L e C2276T, nos genes BDNF, p75NTR e PRKG1, respectivamente, na etiopatogenia do suicídio, numa amostra da população Portuguesa seleccionada no decorrer de autópsias médico-legais, realizadas no Instituto Nacional de Medicina Legal. Os resultados obtidos para o polimorfismo Val66Met do gene BDNF não revelaram associação entre este polimorfismo e o suicídio na globalidade da amostra, na estratificação por género ou método de suicídio. Desta forma, o polimorfismo Val66Met do gene BDNF parece não desempenhar um papel importante na etiologia do suicídio. Quanto ao gene p75NTR, os resultados do estudo para a amostra de indivíduos do sexo masculino mostraram uma tendência de associação, e uma associação para o genótipo (χ2=5,302; df=2; p=0,071) e para o alelo (χ2=5,269; df=1; p=0,022),respectivamente, o que permite sugerir que o polimorfismo do gene p75NTR poderá ser um factor de risco para o suicídio no sexo masculino. Contrariamente, a amostra de indivíduos do sexo feminino não revelou alterações significativas. No que diz respeito à amostra no seu todo, e estratificada por método de suicídio, não se detectarem alterações significativas na distribuição genotípica e nas frequências alélicas. Relativamente ao polimorfismo C2276T do gene PRKG1, não foi obtida associação com o suicídio para a totalidade da amostra, bem como na estratificação por género e método de suicídio. Contudo, para a distribuição genotípica, foi obtida uma tendência de associação entre o polimorfismo C2276T do gene PRKG1 e o suicídio para indivíduos do sexo feminino (χ2=5,361; df=2; p=0,069). Face a este resultado, é importante fazer estudos adicionais para tentar esclarecer o papel do gene PRKG1 no suicídio, em particular no sexo feminino. Tendo em conta os resultados obtidos, nomeadamente para o receptor p75NTR, a hipótese do envolvimento de variantes genéticas das neurotrofinas é promissora, na etiologia do suicídio. A possível identificação de factores genéticos disponibilizará um contributo para uma melhor compreensão da etiologia do suicídio e potencialmente para a prevenção do comportamento suicida, reduzindo desta forma a taxa de suicídio.respectivamente, o que permite sugerir que o polimorfismo do gene p75NTR poderá ser um factor de risco para o suicídio no sexo masculino. Contrariamente, a amostra de indivíduos do sexo feminino não revelou alterações significativas. No que diz respeito à amostra no seu todo, e estratificada por método de suicídio, não se detectarem alterações significativas na distribuição genotípica e nas frequências alélicas. Relativamente ao polimorfismo C2276T do gene PRKG1, não foi obtida associação com o suicídio para a totalidade da amostra, bem como na estratificação por género e método de suicídio. Contudo, para a distribuição genotípica, foi obtida uma tendência de associação entre o polimorfismo C2276T do gene PRKG1 e o suicídio para indivíduos do sexo feminino (χ2=5,361; df=2; p=0,069). Face a este resultado, é importante fazer estudos adicionais para tentar esclarecer o papel do gene PRKG1 no suicídio, em particular no sexo feminino. Tendo em conta os resultados obtidos, nomeadamente para o receptor p75NTR, a hipótese do envolvimento de variantes genéticas das neurotrofinas é promissora, na etiologia do suicídio. A possível identificação de factores genéticos disponibilizará um contributo para uma melhor compreensão da etiologia do suicídio e potencialmente para a prevenção do comportamento suicida, reduzindo desta forma a taxa de suicídio.
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Wang, Ting Chung, and 王定中. "Establishment of an experimental glioma model in rats and functional characterization of p75NTR in glioma tumorigenesis." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/wf48k4.
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Schüle, Susann-Cathrin. "Die Bedeutung des p75-Neurotrophinrezeptors während der De- und Remyelinisierung im Cuprizon- Modell der Multiplen Sklerose." Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-001D-AF1C-3.
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