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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Investigating the effect of PIP4K2a overexpression in insulin signalling in L6 myotubes

Al-Abri, Abdulrahim January 2018 (has links)
Insulin signalling is an essential process in humans by which the level of plasma glucose is maintained within the physiologically healthy range. Insulin activates the phosphoinositide 3 kinase (PI3K) signalling pathway that generates the phospholipid messenger PtdIns(3,4,5)P3, which in turn enhances the activity of two important proteins, AKT and Rac1. This then leads to increase the presence of the glucose transporter 4 (GLUT4) at the plasma membrane that enhances the intake of glucose, particularly in skeletal muscle cells and adipocytes. Insulin signalling also triggers interconversion of several other phosphoinositides (PIs) which play pivotal roles in different steps of glucose regulation. PtdIns5P is an important PI that is robustly increased after insulin treatment in the skeletal muscle cell line, L6 myotubes. Many of PtdIns5P`s functions are not fully understood. To gain more knowledge of the role of PtdIns5P in insulin signalling in muscle cells, the PtdIns5P kinase phosphatidylinositol-5-phosphate 4-kinase a (PIP4K2a) was over-expressed in L6 myotubes as a way of removing PtdIns5P, and the consequences in insulin signalling were studied. Although PtdIns5P is converted by PIP4K2a to PtdIns(4,5)P2 which is a precursor of the potent PI PtdIns(3,4,5)P3, previous studies revealed that the increase in PtdIns(3,4,5)P3 induced by insulin in control cells is diminished in cells overexpressing PIP4K2a, for unknown reasons. Additionally, although the phosphorylation of the serine/threonine protein kinase AKT was not affected in these L6 cells, glucose uptake was attenuated. The current study investigates the possible causes of attenuating glucose uptake in PIP4K overexpressing myotubes by examining the small GTPase Rac1 which plays an important role in the cytoskeleton re-arrangement that is necessary for GLUT4 translocation. Furthermore, the possible roles of PI phosphatases that may cause the disturbance on the levels of PIs in response to insulin were evaluated. Additionally, the potential role of PtdIns5P in Rac1 activation in L6 myotubes was further investigated by delivering synthetic PtdIns5P using a carrier-based delivery approach. The results showed that the attenuation of glucose uptake documented in previous studies occurred as a result of a defect in the process of translocating GLUT4 from intracellular storage to the plasma membrane. Rac1 activity was significantly reduced in cells expressing PIP4K2a. Quantifying the level of PIs suggested that PIP4K2a expression increases the removal of PtdIns(3,4,5)P3 by the PI 5-phosphatase, SKIP. Silencing the expression of SKIP by siRNA restored the level of PtdIns(3,4,5)P3 but Rac1 activity and the attenuation GLUT4 translocation were not rescued possibly as a result of removing PtdIns5P by PIP4K2a. On the other hand, exogenous delivery of PtdIns5P in L6 myotubes activates both Rac1 and GLUT4 translocation in the absence of insulin. However, activating GLUT4 translocation by the exogenous PtdIns5P requires PI3K activity since redistribution of GLUT4 to the plasma membrane is inhibited by the PI3K inhibitor, wortmannin. Removing PtdIns5P reduces Rac1 activity and stimulates SKIP that inhibits PtdIns(3,4,5)P3 increase which attenuates GLUT4 translocation and hence glucose uptake. These results emphasise the critical role played by PtdIns5P which seems to serve as a regulator of insulin signalling, both directly and/or by regulating other enzymes involved in the metabolism of PIs.
212

Spolupráce EU - AKT na příkladu Haiti / EU-ACP Cooperation with a case study on Haiti

Palková, Anežka January 2011 (has links)
This thesis focuses on cooperation of the European Union with the African, Carribean and Pacific Group of States. Its aim is to describe the relations in a complex way and to record the changes that are connected with the evolution of cooperation. Attention is also paid to conditionality of cooperation. Introductory part describes EU development cooperation and humanitarian aid. Historical evolution of EU-ACP cooperation follows together with the details on the Cotonou Agreement. Last part is the case study on Haiti.
213

Avaliação imunoistoquímica das proteínas metalotioneína, pAKT e NF-kB como marcadores de prognóstico de carcinomas epidermóides de boca / Immunohistochemical evaluation of Metallothionein, pAkt and NF-kB proteins as prognostic factors of Oral Squamous Cell Carcinoma

Helder Antonio Rebêlo Pontes 26 May 2008 (has links)
O carcinoma epidermóide é a neoplasia maligna que ocorre com maior freqüência na boca. Os pacientes portadores desta neoplasia ainda apresentam um pobre prognóstico com índices de sobrevida, em cinco anos, variando de 20 a 40% em vários estudos. Um grande número de trabalhos tem sido direcionado para identificar marcadores que auxiliem no direcionamento do tratamento e melhorem o prognóstico. A metalotioneína (MT) é uma proteína de baixo peso molecular, com alto conteúdo de cisteína e que está associada à resistência neoplásica a várias modalidades de tratamento, e que por isso tem sido estudada como fator prognóstico em uma variedade de neoplasias malignas humanas. O Fator Nuclear B desempenha um importante papel na ativação de genes que estão relacionados à imunidade, inflamação, sobrevida, apoptose, proteção celular à radiação e à quimioterapia. A proteína serina/treonina quinase Akt é um alvo downstream da quinase 3-fosfaditilinositol, desempenhando um importante papel na proliferação e no bloqueio da apoptose de células cancerígenas. Neste estudo, nós examinamos a expressão das proteínas MT, NF-kB e pAKT em 51 casos de carcinomas epidermóides de boca, através de imunoistoquímica, com a finalidade de investigar suas influências prognosticas, assim como estudar as correlações entre alguns fatores clínicos com a sobrevida. Os resultados mostraram uma associação estatisticamente significante entre a expressão pAkt e NF-kB e entre MT e NF-kB. Ao lado disso, nossos resultados mostraram que a expressão de pAkt está associada a um pior prognóstico. Nossos resultados, portanto, sugerem que a proteína pAkt pode ter implicações terapêuticas em carcinomas epidermóides de boca. / Oral squamous cell carcinoma (OSCC) is the most frequent malignant tumor of the oral cavity. In spite of improved therapeutic procedures, patients with OSCC in advanced stage generally present a poor prognosis, with an overall 5-year survival rate that ranges from 20% to 40%. An extensive effort has started to identify features of the oral tumors that predict treatment response and prognosis. The metallothionein (MT), a low-molecular weight protein with high cysteine content, seems to be related to neoplastic resistance to oncologic treatment and therefore has been studied as a prognostic factor for a variety of human malignant tumors. The nuclear factor B (NF-B) plays an important role in the activation of the genes that code for immunity, survival, inflammation, apoptosis and in the cell protection for radiation and chemotherapy. The serine/threonine protein kinase Akt is a downstream target of phosphatidylinositol-3-kinase and it plays a key regulator of cancerous cell growth. Therefore, we have examined the MT, NF-kB and pAkt expression in 51 samples of oral squamous cell carcinoma by immunohistochemistry in order to investigate their prognostic influence on oral cancer, as well as studying the correlations between clinical factors and patient survival. The results showed a significant association between pAkt and NF-kB and between MT and NF-kB expression in tumor tissue. Besides pAkt over-expression was found in OSCC clinical samples and its expression was significantly associated with a poor overall patient survival. In conclusion, our findings suggested that pAkt expression may have therapeutic implications in squamous cell carcinoma.
214

A participação da via fosfatidilinositol3-quinase (PI3K)/mTOR no carcinoma epidermoide oral / The participation of the pathway Phosphatidylinositol 3-kinase (PI3K) / mTOR in oral squamous cell carcinoma

Andressa Duarte 15 March 2018 (has links)
O carcinoma epidermoide oral (CEO) possui alta incidência no Brasil, correspondendo a aproximadamente 95% das neoplasias malignas orais. A biologia molecular do carcinoma de cabeça e pescoço é complexa e se desenvolve a partir da disfunção de várias vias inter-relacionadas. A via das PI3K/mTOR é conhecida por regular várias funções celulares, como a regulação do ciclo celular, migração, angiogênese, morfologia e organização do citoesqueleto. O presente trabalho teve como objetivo avaliar o impacto do bloqueio da via PI3K e mTOR na sobrevida celular, na adesão e na morfologia de células endoteliais, relacionando-o com o processo angiogênico. Em cultura de células, observamos que as inibições farmacológicas de PI3K ou do mTOR diminuem a viabilidade celular do CEO. Houve redução da expressão de PARP, um marcador de apoptose e pS6, uma proteína dowstream na sinalização do mTOR, após o tratamento das células de CEO com os inibidores de mTOR. Além disso, demonstramos que o tratamento com os inibidores de mTOR diminuem a capacidade das células do CEO em formarem clones. Foi observado ainda que o cultivo de célula endoteliais da veia umbilical humana (HUVEC, do inglês Human Umbilical Vein Endothelial Cells) em meio condicionado (MC) proveniente de células de CEO, tratadas com inibidores de mTOR, resultaram em aumento da adesão celular e modificação na morfologia celular. Para investigar a influência dos fatores liberados pelas células tumorais na migração das células HUVECs, foi realizado ensaio de wound healing, em células HUVECs cultivadas em MC. Observamos maior migração das células HUVECs cultivadas em MC quando este era proveniente de células cancerosas tratadas com inibidor de mTOR. Ainda, investigamos a expressão da via VEGF nessa migração por meio do ensaio de ELISA. Observamos que no MC proveniente de células cancerosas tratadas com inibidor de mTOR havia maior presença de VEGF. Nossos dados sugerem que a via da PI3K/mTOR está envolvida na proliferação das células do CEO. Porém, a inibição de mTOR em células cancerosas pode liberar fatores, tais como VEGF, que influenciam na morfologia e migração de células HUVEC. / Oral squamous cell carcinoma (OSCC) has a high incidence in Brazil, corresponding to approximately 95% of oral malignancies. The molecular biology of head and neck carcinoma is complex and develops from the dysfunction of several interrelated pathways. The PI3K/mTOR pathway is known to regulate various cellular functions, such as cell cycle regulation, migration, angiogenesis, cytology, and cytoskeletal organization. The aim of the present study was to evaluate the impact of PI3K and mTOR pathway blockade on cell survival, endothelial cell adhesion and morphology, and to correlate it with the angiogenic process. In cell culture, we observed that pharmacological inhibitions of PI3K or mTOR decrease the OSCC\'s cellular viability. There was a reduction in the expression of PARP, a marker of apoptosis and pS6, a dowstream protein in mTOR signaling, after treatment of OSCC cells with mTOR inhibitors. In addition, we have demonstrated that treatment with mTOR inhibitors decreases the ability of the OSCC cells to form clones. It was further noted that human umbilical vein endothelial cell (HUVEC) culture in conditioned media (CM) from OSCC cells treated with mTOR inhibitors resulted in increased cell adhesion and modification in cell morphology. To investigate the influence of the factors released by the tumor cells in the migration of HUVEC cells, a wound healing assay was performed on HUVEC cells cultured in CM. We observed a greater migration of HUVECs cells cultured in CM when it came from cancer cells treated with mTOR inhibitor. Furthermore, we investigated the role of the VEGF pathway in this migration through the ELISA assay. We observed that in CM from cancer cells treated with mTOR inhibitor there was a greater presence of VEGF. Our data suggest that the PI3K/mTOR pathway is involved in the proliferation of OSCC cells. However, inhibition of mTOR in cancer cells may release factors, such as VEGF, which influence the morphology and migration of HUVEC cells.
215

Regulation of human primordial follicle activation in vitro

Grosbois, Johanne 31 January 2019 (has links) (PDF)
Producing competent and fertilizable oocytes from in vitro grown primordial follicles could revolutionize female infertility treatment, particularly using fertility preservation approaches that use cryopreserved ovarian tissue. However, the protracted length of folliculogenesis in humans makes follicular culture complex, and the mechanisms controlling the tightly-regulated activation of primordial follicles remain largely unknown. The delicate balance between follicular recruitment and quiescence might be affected by preservation procedures, such as ovarian fragmentation or in vitro culture, that disrupt crucial pathways, such as the Hippo and PI3K/Akt/mTOR signaling pathways, that are involved in this process. When activated, these pathways induce massive recruitment of primordial follicles and accelerate follicular growth in vitro, with potential negative consequences on future oocyte developmental competence. Therefore, we hypothesized that the inhibition of the PI3K/Akt/mTOR pathway might improve follicular growth by slowing down the activation process.In the first part of this thesis, we explored the potential benefit of inhibiting PI3K/Akt/mTOR signaling on the regulation of in vitro follicular activation and growth, as well as its impact on the Hippo pathway. The effect of everolimus (EVE), a specific mTORC1 inhibitor, was compared to the PI3K/Akt activators recently used to reinitiate the growth of residual follicles in the ovarian tissue of patients with premature ovarian insufficiency. We showed that short-term incubation of ovarian cortex with EVE partially delayed follicular recruitment while supporting follicle survival and steroidogenesis. However, morphological abnormalities were observed in all conditions, suggesting that EVE failed to protect follicles from accelerated in vitro growth-related defects.Our findings also provided evidence that ovarian fragmentation, which disrupts the Hippo pathway, contributes to the triggering of primordial follicle recruitment and early development of quiescent human follicles. Moreover, our data suggested that both PI3K/Akt and Hippo signaling could act synergistically to promote follicular activation and growth.In the second part of the project, we further investigated the integrity of EVE-treated follicles based on their ultrastructural and functional status. Our observations indicate that the integrity of oocyte and granulosa cells, as well as their physical contacts, were preserved in EVE and control conditions, although some in vitro grown follicles sustained cryopreservation- and culture- induced damage. We also found that short exposure to EVE allowed the maintenance of intra-follicular communication while preserving follicular developmental potential. Importantly, results obtained suggested that, at a similar developmental stage, cell coupling and oocyte growth may be improved in EVE-treated follicles.Altogether, these data provide better insight into the regulation of the follicular activation process and emphasize the importance of getting closer to physiological conditions to preserve follicle integrity. They also provide proof-of-concept evidence that reducing the initiation of growth is feasible, and suggest that mTORC1 inhibitors are a potentially useful pharmacological tool to regulate in vitro follicular growth. / La production d'ovocytes compétents et fécondables à partir de follicules primordiaux développés in vitro pourrait révolutionner les traitements liés à l'infertilité féminine, en particulier les approches de préservation de la fertilité à partir du tissu ovarien cryopréservé. Cependant, la longue durée de la folliculogenèse chez l'Homme rend la culture folliculaire complexe, et les mécanismes contrôlant l'activation des follicules primordiaux restent largement inconnus. L’équilibre fragile entre quiescence folliculaire et entrée en croissance pourrait être affecté par la fragmentation ovarienne ou la culture in vitro elle-même, qui perturbent deux voies de signalisation cruciales: les voies Hippo et PI3K/Akt/mTOR, respectivement. Lorsqu'elles sont activées, elles induisent un recrutement massif de follicules primordiaux et accélèrent la croissance folliculaire in vitro, avec des conséquences potentiellement néfastes sur la capacité future des ovocytes à devenir compétents. Par conséquent, nous avons émis l’hypothèse que l’inhibition de la voie PI3K/Akt/mTOR pourrait améliorer la croissance folliculaire via un ralentissement du processus d’activation.Dans la première partie de cette thèse, nous avons exploré le potentiel bénéfice d’une inhibition de la voie PI3K/Akt/mTOR sur la régulation de l'activation et de la croissance folliculaire in vitro, ainsi que son impact sur la voie Hippo. L’effet de l’évérolimus (EVE), un inhibiteur spécifique de mTORC1, a été comparé à ceux d’activateurs de PI3K/Akt, récemment utilisés afin d’initier la croissance des follicules résiduels au sein de tissus ovarien de patientes en insuffisance ovarienne précoce. Nous avons montré que l'exposition à court terme de cortex ovarien à l'EVE retardait partiellement le recrutement folliculaire tout en préservant la survie et la stéroidogenèse des follicules. Toutefois, des anomalies morphologiques ont été observées dans toutes les conditions, ce qui suggère que l’EVE ne préserve pas les follicules de défauts liés à une croissance accélérée.Nos résultats ont également prouvé que la fragmentation ovarienne, en perturbant la voie Hippo, contribue au recrutement et au développement précoce des follicules primordiaux. De plus, les données obtenues suggèrent que les voies PI3K/Akt/mTOR et Hippo pourraient agir de manière synergique pour promouvoir l'activation et la croissance folliculaire.Dans la deuxième partie du projet, nous avons étudié la qualité des follicules traités avec de l’EVE en se basant sur des critères ultrastructural et fonctionnel. Nos observations ont indiqué que l'intégrité des ovocytes et des cellules de la granulosa ainsi que leurs contacts physiques était préservée dans les conditions EVE et contrôle, bien que certains follicules en croissance présentent des signes de dommages induits par la cryopréservation et la culture. Nous avons également constaté qu'une courte exposition à l’EVE permettait de maintenir les communications intra-folliculaires tout en préservant le potentiel de développement des follicules. De façon importante, les résultats obtenus suggèrent qu’à un stade de développement similaire, le couplage cellulaire et la croissance des ovocytes pourraient être améliorés dans les follicules traités à l’EVE.En conclusion, ces données contribuent à une meilleure compréhension de la régulation de l'activation folliculaire in vitro, et soulignent l'importance de mimer les conditions physiologiques pour préserver l'intégrité des follicules. Elles apportent également la preuve qu’un ralentissement de l’initiation de la croissance est réalisable, et suggèrent que l’utilisation d’inhibiteurs de mTORC1 pourrait représenter un outil pharmacologique efficace pour réguler la croissance folliculaire in vitro. / Doctorat en Sciences biomédicales et pharmaceutiques (Médecine) / info:eu-repo/semantics/nonPublished
216

Papel da progesterona como possível neuroprotetor em modelo de hipóxia-isquemia encefálica neonatal

Fabres, Rafael Bandeira January 2016 (has links)
A encefalopatia hipóxico-isquêmica neonatal, ou simplesmente hipóxia-isquemia (HI) neonatal, é uma das principais causas de morbidade e mortalidade em neonatos humanos. De 20% a 50% dos recém-nascidos com HI severa morrem no período perinatal. Quando sobrevivem, 25% apresentam deficiências neuropsicológicas, como dificuldade de aprendizado, epilepsia e paralisia cerebral. Devido a isso, a eficácia de possíveis agentes neuroprotetores tem sido testada em modelos animais. Há razão para se pensar que a progesterona tem um forte potencial para o tratamento da HI neonatal, já que a sua utilização tem se mostrado benéfica em pesquisas relacionadas com lesão cerebral traumática, lesão cerebral isquêmica e outros modelos de lesão do sistema nervoso central (SNC) em adultos. Inúmeros estudos têm mostrado que o modelo animal de HI de Rice e Vannucci (1981) em animais neonatos, utilizado no presente trabalho, pode produzir lesões no sistema nervoso central relativamente previsíveis, e que estas lesões encefálicas parecem semelhantes às observadas clinicamente em humanos (SALMASO et al., 2014). Para a realização do modelo de HI foram utilizados ratos Wistar com idade de 7 dias (P7). Após a oclusão da carótida esquerda, os animais foram colocados em câmaras para exposição à atmosfera hipóxica com 8% O2/92% N2 por 90 minutos. Os animais foram divididos em cinco grupos experimentais: SHAM, HI, HI+PROG-PRÉ (PRÉ), HI+PROG-PÓS (PÓS), HI+PROG-PRÉ/PÓS (PP). Os termos PRÉ e PÓS referem-se à administração de progesterona (na dose de 5 mg/kg) antes ou após o procedimento de HI neonatal . Dependendo do grupo experimental, os animais foram tratados com progesterona imediatamente antes da isquemia e/ou 6 e 24 horas após o início da hipóxia. Foram analisados o peso corporal dos animais (imediatamente antes da isquemia e 6, 24 e 48 horas após o início da hipóxia), o volume de lesão cerebral, além da expressão das proteínas p-Akt e caspase-3 pela técnica de Western blotting. / Neonatal hypoxic-ischemic encephalopathy or simply neonatal hypoxia-ischemia (HI) is a main cause of morbidity and mortality in human neonates. Moreover, 25% of survivors show neuropsychological dysfunctions such as learning difficulties, epilepsy and cerebral palsy. Because of this, the effectiveness of potential neuroprotective agents has been tested in animal models. There is a reason to suppose that progesterone has a strong potential for the treatment of neonatal HI since its use has been shown to be beneficial in researches related to traumatic brain injury, ischemic brain injury and other central nervous system injury models (CNS) in adults. Several studies have shown that the newborn animal model of HI developed by Rice and Vannucci (1981), and used in the present study, can produce lesions in the central nervous system which are predictable and similar to those observed clinically in humans. In order to perform the HI model we used 7 days old (P7) Wistar rats. After occlusion of the left carotid, the animals were placed in hypoxic chambers and exposed to the hypoxic atmosphere (8% O2/92% N2 for 90 minutes). The animals were divided into five groups: SHAM, HI, HI+PROG-PRÉ (PRÉ), HI+PROG-PÓS (PÓS), HI+PROG-PRÉ/PÓS (PP).The PRÉ and PÓS terms refer to the administration of progesterone (5 mg/kg) before and/or after the HI procedure. Progesterone was administered immediately before ischemia, 6 and 24 hours after the beginning of hypoxia, depending on the experimental group. Body weight was evaluated immediately before ischemia and/or 6 and 24 hours after the start of hypoxia. The volume of brain damage, in addition to the expression of p-Akt and caspase-3 were also evaluated.
217

A participação da via fosfatidilinositol3-quinase (PI3K)/mTOR no carcinoma epidermoide oral / The participation of the pathway Phosphatidylinositol 3-kinase (PI3K) / mTOR in oral squamous cell carcinoma

Duarte, Andressa 15 March 2018 (has links)
O carcinoma epidermoide oral (CEO) possui alta incidência no Brasil, correspondendo a aproximadamente 95% das neoplasias malignas orais. A biologia molecular do carcinoma de cabeça e pescoço é complexa e se desenvolve a partir da disfunção de várias vias inter-relacionadas. A via das PI3K/mTOR é conhecida por regular várias funções celulares, como a regulação do ciclo celular, migração, angiogênese, morfologia e organização do citoesqueleto. O presente trabalho teve como objetivo avaliar o impacto do bloqueio da via PI3K e mTOR na sobrevida celular, na adesão e na morfologia de células endoteliais, relacionando-o com o processo angiogênico. Em cultura de células, observamos que as inibições farmacológicas de PI3K ou do mTOR diminuem a viabilidade celular do CEO. Houve redução da expressão de PARP, um marcador de apoptose e pS6, uma proteína dowstream na sinalização do mTOR, após o tratamento das células de CEO com os inibidores de mTOR. Além disso, demonstramos que o tratamento com os inibidores de mTOR diminuem a capacidade das células do CEO em formarem clones. Foi observado ainda que o cultivo de célula endoteliais da veia umbilical humana (HUVEC, do inglês Human Umbilical Vein Endothelial Cells) em meio condicionado (MC) proveniente de células de CEO, tratadas com inibidores de mTOR, resultaram em aumento da adesão celular e modificação na morfologia celular. Para investigar a influência dos fatores liberados pelas células tumorais na migração das células HUVECs, foi realizado ensaio de wound healing, em células HUVECs cultivadas em MC. Observamos maior migração das células HUVECs cultivadas em MC quando este era proveniente de células cancerosas tratadas com inibidor de mTOR. Ainda, investigamos a expressão da via VEGF nessa migração por meio do ensaio de ELISA. Observamos que no MC proveniente de células cancerosas tratadas com inibidor de mTOR havia maior presença de VEGF. Nossos dados sugerem que a via da PI3K/mTOR está envolvida na proliferação das células do CEO. Porém, a inibição de mTOR em células cancerosas pode liberar fatores, tais como VEGF, que influenciam na morfologia e migração de células HUVEC. / Oral squamous cell carcinoma (OSCC) has a high incidence in Brazil, corresponding to approximately 95% of oral malignancies. The molecular biology of head and neck carcinoma is complex and develops from the dysfunction of several interrelated pathways. The PI3K/mTOR pathway is known to regulate various cellular functions, such as cell cycle regulation, migration, angiogenesis, cytology, and cytoskeletal organization. The aim of the present study was to evaluate the impact of PI3K and mTOR pathway blockade on cell survival, endothelial cell adhesion and morphology, and to correlate it with the angiogenic process. In cell culture, we observed that pharmacological inhibitions of PI3K or mTOR decrease the OSCC\'s cellular viability. There was a reduction in the expression of PARP, a marker of apoptosis and pS6, a dowstream protein in mTOR signaling, after treatment of OSCC cells with mTOR inhibitors. In addition, we have demonstrated that treatment with mTOR inhibitors decreases the ability of the OSCC cells to form clones. It was further noted that human umbilical vein endothelial cell (HUVEC) culture in conditioned media (CM) from OSCC cells treated with mTOR inhibitors resulted in increased cell adhesion and modification in cell morphology. To investigate the influence of the factors released by the tumor cells in the migration of HUVEC cells, a wound healing assay was performed on HUVEC cells cultured in CM. We observed a greater migration of HUVECs cells cultured in CM when it came from cancer cells treated with mTOR inhibitor. Furthermore, we investigated the role of the VEGF pathway in this migration through the ELISA assay. We observed that in CM from cancer cells treated with mTOR inhibitor there was a greater presence of VEGF. Our data suggest that the PI3K/mTOR pathway is involved in the proliferation of OSCC cells. However, inhibition of mTOR in cancer cells may release factors, such as VEGF, which influence the morphology and migration of HUVEC cells.
218

Chronic Morphine Effect on Inflammatory Cytokine Production in Activated BV-2 Microglia Cell Line via Akt/Gsk3β Signaling

Makinwa, Yetunde R 01 May 2016 (has links)
The pathophysiology of chronic morphine on the immune system, especially on the cells of the innate immune system that leads to an immune compromise state has not been fully elucidated. The cells of the innate immune system are the first line of defense in mounting an immune response needed in infections, inflammation, cancer development, etc. One of the ways by which these innate immune cells act is by the production of cytokines with direct effects and to also recruit other immune cells, as required. A balance of pro- and anti-inflammatory cytokines is necessary for immune competence. I hypothesized that chronic morphine would act via a classical opioid receptor to stimulate the PI3K/Akt/Gsk3β pathway to produce predominantly anti-inflammatory cytokines. Cytokine gene expression levels were assessed via RT-PCR; Akt and Gsk3β protein levels measured using indirect ELISA. The data suggests that chronic morphine causes a significant reduction in IL-6 production, but does not act via the Akt/Gsk3β pathway or the classical opioid receptor to cause this effect in microglia cells.
219

CTRP3 Protects Liver Cells From Alcohol-Induced Damage, But Not Through Enhanced Akt Signaling Type

Lee, Matthew L., Peterson, Jonathan M. 01 April 2014 (has links)
Alcoholic fatty liver disease (AFLD) is a significant public health concern. Excessive alcohol (ethanol) consumption causes liver cell damage and death, which results in eventual failure of the liver and death. AFLD is the number one cause of liver-related mortality in the United States. Our lab works with the novel protein C1q TNF Related Protein 3 (CTRP3), which inhibits non-alcoholic fatty liver disease, however the effects on AFLD are unknown. Therefore, the purpose of this experiment is to determine if CTRP3 prevents ethanol-induced liver cell death. The H4IIE rat hepatoma cell line was chosen for experimentation as a cell culture model of liver tissue. To determine a suitable alcohol level H4IIE cells were treated with 50, 100, and 200 mmol of ethanol for 18-24 hours. Trypan Blue was used to identify the dead/damaged cells, as only dead/damaged cells will be stained blue with this protocol. We observed that 100 mmol of ethanol consistently induced ~10% mortality rate in these cells. Next, we tested the ability of CTRP3 to reduce ethanol-induced mortality. We added purified CTRP3 protein to the cell media along with the 100 mmol ethanol treatment. The addition of CTRP3 reduced the amount of alcohol-induced cell death/damage in the H4IIE cell line by approximately 60%. Our next goal was to determine how CTRP3 reduces ethanol-induced death. The Akt signaling pathway is a well-known inhibitor of cell death. Therefore, to determine if CTRP3 attenuated ethanol-induced cell damage/death through activation of the Akt signaling pathway, another set of cells was treated with 100 mmol of ethanol and CTRP3 (with or without insulin). Western blots were used to compare the amount of active Akt (phosphorylated) in the CTRP3-treated and non-treated cells. A Western blot utilizes an electric current to separate denatured protein samples on a SDS-page gel, separating the proteins based on size. The smaller the protein the faster it migrates across the gel. The proteins are then transferred to a membrane for analysis, through exposure to commercial antigens and chemiluminescence imaging. There was no change in the amount of total or active Akt between the samples treated with or without CTRP3. We conclude that CTRP3 protects liver cells from ethanol-induced damage/death, but not through activation of the Akt pathway.
220

Ethanol Disrupts Metabolic Signaling in Liver Cells

Lee, Matthew L., Peterson, Jonathan M. 01 April 2014 (has links)
Alcohol abuse is the third leading cause of preventable death in the United States. Excessive intake of alcohol can result to alcoholic fatty liver disease, the number one cause of live related mortalities in the US. The outlining purpose for this project is to determine the alcohol-induced changes in the liver cell protein signaling. For this project, we treated H4IIE rat hepatoma cells (with 100 and 200 mM ethanol overnight). H4IIE cells were chosen because they are a commonly used liver cell culture line that maintains characteristics of intact liver cells. After treatment we collected and prepared the cells for protein signaling analysis, using standard western blotting procedure. A western blot detects relative quantity of proteins in a sample. Briefly, protein samples are separated by size through electrophoresis, smaller proteins move faster through the gel so that the larger proteins are toward the top and smaller towards the bottom. The proteins are then transferred to a nitrocellulose membrane and protein concentration is detected by chemiluminescence. We chose to examine the effects of ethanol on the activation of the key regulator of metabolic signaling, Protein Kinase B/Akt (Akt). Based on our results, ethanol has no effect on the total amount of Akt in the H4IIE liver cells. However, ethanol significantly attenuates insulin-induced activation of Akt in a dose-dependent manner, as seen by a reduction in the amount of phosphorylated Akt. Therefore, we conclude that treatments that increase Akt activation may be a viable option for the treatment of alcoholic fatty liver disease.

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