Skeletal muscle secretes many signalisation proteins named myokines. These myokines act as hormones and induce metabolic changes throughout the whole body to facilitate adaptation to physical exercise. Interleukin-15 (IL-15) is highly expressed in skeletal muscle and appears to influence many metabolic parameters that are defective in metabolic pathologies such as insulin resistance. For instance, IL-15 increases glucose uptake in muscle and whole-body fatty acid oxidation and its overexpression in skeletal muscle in mice generates a very lean and active phenotype. However, there are discordant reports throughout scientific literature. The aim of the current study was to 1) characterize the metabolic effects of IL-15 in L6 myotubes to determine whether L6 is a good model to study IL-15 and 2) to determine whether IL-15 activates the AMPK signaling. L6 myotubes were exposed to different concentrations of IL-15 and different metabolic parameters were assayed namely; oxygen consumption, glucose uptake, fatty acid oxidation, Glucose transporter 4 (GLUT4) translocation, oxidative phosphorylation (OXPHOS) complexes protein expression, troponin T expression and Akt, AMPK and Acetyl-CoA Carboxylase (ACC) phosphorylation state. Acute IL-15 treatment increased glucose uptake without activating insulin signaling pathway or GLUT4 translocation. Furthermore, acute IL-15 treatment increased resting oxygen consumption rate (OCR) while chronic IL-15 treatment also increased mitochondrial spare capacity, suggesting an increased mitochondrial biogenesis. IL-15 induced ACC phosphorylation in a dose-dependent manner and tended to increase AMPK phosphorylation but it did not reach statistical significance. Lastly, IL-15 did not influence troponin T state. Altogether, the present study demonstrates that L6 myotubes do not express all the pro-oxidative qualities of IL-15 reported by scientific literature. Nonetheless, IL-15 induces certain pro-oxidative metabolic effect that could help people living with obesity and diabetes.

Natural killer (NK) cells were so named for their uniqueness in killing certain tumor and virus-infected cells without prior sensitization unlike T lymphocytes. NK cells possess a myriad of activation receptors and cytokine receptors that allow them to recognize stress ligands on infected/tumor cells and respond to the cytokines produced during the inflammatory process. Upon activation, NK cells produce pro-inflammatory cytokines, cytotoxic granules and chemokines to recruit other cells which ultimately result in killing of target cells. These functions of NK cells are modulated in vivo by several immune mediators; IL-15 being the most potent in enabling NK cell homeostasis, maturation and activation. Indeed, IL-15 knockout mice have no detectable NK cells. During microbial infections, NK cells stimulated with IL-15 display enhanced cytokine responses. This priming effect has previously been shown with respect to increased IFN-γ production in NK cells upon IL-12 and IL-15/IL-2 co-stimulation. In this study, I explored if this effect of IL-15 priming can be extended to other cytokines and observed enhanced NK cell responses to stimulation with IFN-, IL-21, IL-2 and IL-4 in addition to IL-12. Notably, we also observed elevated IFN-γ production in primed NK cells upon stimulation through the Ly49H activation receptor. IL-15 treatments induced NK cell proliferation, enhanced NK cell responses to activating stimuli and equipped them with cytotoxic granules thereby “readying” them for battle against infections and tumors. Here, we try to understand the signaling mechanisms underlying IL-15 treatments that activate NK cells. Currently, the fundamental processes required for priming and whether these signaling pathways work collaboratively or independently for NK cell functions are poorly understood. To identify the key signaling events, we examined IL-15 priming on NK cells in which the pathways emanating from IL-15 receptor activation were blocked with specific inhibitors. Our results demonstrate that the PI3K-AKT-mTOR pathway is indispensable for cytokine responses in IL-15 primed NK cells. Furthermore, this pathway is also implicated in a broad range of IL-15 induced NK cell effector functions such as proliferation and cytotoxicity. Given that NK cells are critical for control of viral infections like murine cytomegalovirus (MCMV), we decided to analyze the consequences of blocking the PI3K-AKT-mTOR pathway in NK cells on its anti-viral responses. Likewise, NK cells from mice treated with rapamycin to block the mTOR pathway displayed defects in proliferation, IFN-γ and granzyme B production resulting in elevated viral burdens upon MCMV infection. Taken together, our data demonstrates the requirement of PI3K-mTOR pathway for enhanced NK cell functions by IL-15. It also shows that IL-15 primes NK cell responses to several cytokines and to Ly49H activation receptor stimulation. To our knowledge this is first report to demonstrate the requirement of mTOR activity in NK cells for efficient control of acute MCMV infections; thereby coupling the metabolic sensor mTOR to NK cell anti-viral responses.

No description available.

Le cancer du rein (CCR) est une néoplasie immunogène. Le travail présenté ici porte sur les interactions entre les cellules Natural Killer (NK) et les cellules du cancer du rein. Les caractéristiques particulières des cellules tumorales rénales, telles que les mutations de VHL, l’événement phare dans le développement des cancers du rein, ou encore l’expression d’une forme membranaire de la cytokine IL-15 interfèrent avec l’activation des cellules NK. On a identifié une forme membranaire de la cytokine IL-15 particulière sur les cellules tumorales rénales, qui contrôlerait l’homéostasie des cellules NK au sein de la tumeur. Par ailleurs, on montre que certaines mutations de VHL des cellules du cancer du rein favorisent l’activation des cellules NK en diminuant l’expression des molécules HLA de classe I par les cellules tumorales. / Renal cell carcinomas (RCC) are immunogenic. The work presented here describes the interactions between NK cells and RCC. We have investigated particular characteristics of RCC, like the mutation of the VHL gene, the key event in carcinogenesis of kidney cancers of the clear cell type, or a particular expression of IL-15 by the tumor cells. We show that certain RCC cell lines express a unique form of membrane bound IL-15. Our work indicates that the expression of IL-15 by the tumor cells might play a role in the homeostasis of NK cells infiltrating kidney cancers. Furthermore we show that mutations of the VHL gene cause diminished HLA expression favoring thereby the activation of NK.

Orientadores: Áureo Tatsumi Yamada, Michael Joseph Soares / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-18T04:12:34Z (GMT). No. of bitstreams: 1 Lippe_ElianaMaraOliveira_D.pdf: 1508385 bytes, checksum: f80492236b91aa11f6167dbfd5369199 (MD5) Previous issue date: 2011 / Resumo: Um processo de remodelação progressiva da vascularização uterina precede a placentação em humanos e roedores para prover o suprimento sanguíneo adequado na interface materno-fetal, tendo as células NK um papel modulador através da produção de citocinas como o IFN'gama', fatores de crescimento como o VEGF e radicais livres como o óxido nítrico (NO). A regulação das células uNK nesta atividade tem sido atribuída à influência de fatores exógenos como a hipóxia e parácrinos como a prolactin-like protein-A (PLP-A). Contudo, como estes mecanismos são integrados no controle da angiogênese e vasculogênese da interface materno-fetal envolvendo as células uNK não são plenamente compreendidos. No presente trabalho, foram investigadas experimentalmente a resposta das células uNK relacionadas com os mecanismos de regulação dos fatores angiogênicos sob influência da hipóxia no período pré-placentário. Para tanto, foram avaliados camundongos CD1 e geneticamente modificados IL15-/-, PLPA-/- e IL15-/-/PLPA-/- gestantes no 8° dia de gestação (dg), mantidos em hipóxia (42 0Torr - 11%O2) durante 48 horas. Em comparação com os animais mantidos em normóxia (760Torr - 21%O2) a quantidade de sítios anormais apresentou incremento estatisticamente significativo sob hipóxia nos animais CD1, porém este índice era substancialmente maior nos animais depletados dos genes IL15 e PLPA. As amostras dos sítios uterinos de desenvolvimento embrionários coletados foram processados para obtenção de criocortes destinados às reações citoquímicas, imunocitoquímicas e hibridização in situ, e homogeneizados teciduais para extração do RNAm ou proteínas. Conforme esperado, os resultados da citoquímica com lectina DBA e imunocitoquímica de perforina comprovam a ausência de células uNK nos animais IL15-/- e IL15-/-/PLPA-/-, enquanto nos animais PLPA-/-, a incidência das células uNK perforina positivas não difere dos CD1 em normóxia ou hipóxia. A concentração protéica de VEGF e dos genes das isoformas VEGFA, VEGFB e VEGFC, assim como do IFN? e das isoformas iNOS e eNOS, o do TNF? e seus receptores TNFR1 e TNFR2 não apresentaram variações em suas concentrações ou níveis de expressões com padrões definidas de regulação negativa ou positiva entre os animais avaliados. Contudo a imunocitoquímica demonstrou redução de marcação de células endoteliais endoglinpositivas no endométrio e aumento no potencial invasivo de células trofoblásticas TROMA-I positivas dos animais IL15-/-. O conjunto destes resultados confirma que a ausência das células uNK afeta a vascularização normal do endométrio, a qual pode resultar em perdas gestacionais e induz a hipertrofia placentária, sem a participação direta da atividade citotóxica destas células. Comprovam também que os mecanismos de controle da expressão de fatores angiogênicos no útero gestante são multifatoriais, não sendo dependente de uma via única como o da PLPA/VEGF, ou exclusivamente das células uNK como fontes de fatores que modulam a angiogênese na interface maternofetal do útero gestante / Abstract: A gradual process of remodeling of uterine vasculature precedes placentation in humans and rodents to provide adequate blood supply in maternal-fetal interface, where NK cells producing cytokines like growth factor (VEGF) and IFN'gama' and free radical as nitric oxide (NO). Regulation of this uNK cells activity seems to be under influence of exogenous and endogenous factors such as hypoxia as paracrine effects of prolactin-like protein-A (PLPA). Nevertheless, how these mechanisms are integrated in the control of maternal-fetal interface angiogenesis and vasculogenesis involving uNK cells are not fully understood. In this study, we investigated experimentally the uNK cells response related to the mechanisms of regulation of angiogenic factor under hypoxia influence in pre-placental period. Thus, we evaluated genetically modified mice and CD1-IL15-/-, PLPA-/- and IL15-/- /PLPA-/-pregnant on the 8th day of gestation (dg), maintained in hypoxia (420Torr-11%O2) for 48h. When compared to the control animals in normoxia (760Torr-21%O2) the amount of abnormal embryo developing sites showed statistically significant increase under hypoxia in CD1 animals, but this rate was substantially higher in the PLPA and IL15 gene depleted animals. Uterine samples were processed to obtain cryosection for cytochemical, immunocytochemical and in situ hybridization reactions and extraction of mRNA or protein for PCR or ELISA reactions, respectively. As expected, the results of cytochemistry and immunocitochemistry with DBA lectin and perforin prove the absence of uNK cells in IL15-/- and IL15-/-/PLPA-/-animals, while in PLPA-/-animals, the incidence of uNK cells perforinpositive did not differ from CD1 animlas in normoxia or hypoxia. The concentration of protein VEGF and the gene isoforms expression of VEGF (A, B and C), as well as, IFN?, iNOS and eNOS, TNF? and their receptors TNFR1 and TNFR2 did not show constancy in the pattern of variations. However, the immunocytochemistry showed reduced staining of endoglin-positive endothelial cells in the endometrium and increase in invasive potential of trophoblast cells by TROMA-I positive in IL15-/- animals. This set of results confirms that the absence of uNK cells affects the normal vasculature of the endometrium which may increased intrauterine growth restriction (IUGR) or pregnancy failure rates and induces placental hypertrophy. This abnormality at the maternal-fetal interface does not seems to be involves direct participation of cytotoxic activity of uNK cells. Furthemore, the control mechanisms of angiogenic factors expression in the pregnant uterus are multifactorial rather than dependent of a single pathway like the PLP-A/VEGF, or limited to uNK cells as a source of factors that modulate angiogenesis in the maternal-fetal interface of pregnant uterus / Doutorado / Histologia / Doutor em Biologia Celular e Estrutural

Résumé : L’IL-7 et l’IL-15 sont des cytokines impliquées dans l’homéostasie des lymphocytes T CD8 naïfs et mémoires respectivement. Lors d’une réponse immunitaire, certaines cytokines pro-inflammatoires, comme l’IL-6 et l’IL-21, sont produites par les cellules du système immunitaire inné. Nous avons observé que certaines cytokines de ces deux groupes (homéostasie et pro-inflammatoires), peuvent avoir un effet synergique sur la fonction des lymphocytes T CD8. Spécifiquement, l’incubation des lymphocytes T CD8 naïfs avec l’IL-6 ou l’IL-21, en présence d’IL-7 ou d’IL-15 cause une forte prolifération qui est indépendante de l’antigène. De plus, la combinaison d’IL-15 avec l’IL-6 ou l’IL-21 entraîne une prolifération préférentielle des lymphocytes T mémoires, tandis que la combinaison avec l’IL-7 entraîne une prolifération des lymphocytes T naïfs. La stimulation des lymphocytes T CD8 avec l’IL-6 ou l’IL-21, en présence d’IL-7 ou d’IL-15, entraîne une augmentation de la phosphorylation en tyrosine de STAT5 ainsi qu’une augmentation de liaison à l’ADN. Nous avons étudié l’effet d’une pré-stimulation des cellules T CD8 naïves par les cytokines synergiques sur leur réponse subséquente à un antigène. Nous avons observé qu’une pré-stimulation avec l’IL-6 ou l’IL-21, en présence d’IL-7 ou d’IL-15, même pour une courte durée de 24 heures, augmente leur sensibilité aux antigènes, entraînant une robuste prolifération et une forte augmentation de cytotoxité spécifique à l’antigène gp33. Nous avons observé que les cytokines pro-inflammatoires en combinaison avec l’IL-7 induisent une augmentation accrue de la prolifération chez les lymphocytes T CD8 exprimant un TCR transgénique de forte affinité (P14), ainsi que les cellules exprimant un TCR de faible affinité (H-Y). De plus, la combinaison synergique de cytokines entraîne une forte expression du récepteur de l’IL-2R[gamma] (CD132), ainsi qu’une augmentation de la production d’IL-2 après stimulation antigénique. Une forte augmentation de l’expression de CD8 et de CD45, ainsi qu’une diminution drastique de l’expression de CD5 peut expliquer l’augmentation de l’avidité fonctionnelle du TCR suite à une stimulation avec les combinaisons de cytokines synergiques. La stimulation des lymphocytes T CD8 avec les combinaisons de cytokines, induit une augmentation de la phosphorylation de LAT ainsi qu‘AKT. Cependant, la stimulation subséquente du CD3 n’entraîne pas d’augmentation de la phosphorylation de LAT ainsi qu’AKT chez les lymphocytes T CD8 pré-stimulés avec les combinaisons de cytokines. Nous avons aussi observé que les lymphocytes T CD8 stimulés avec les combinaisons de cytokines augmentent l’expression de CD62L, ce qui peut favoriser leur migration vers les ganglions lymphatiques. En conclusion, la production de cytokines pro-inflammatoires (IL-6, IL-15, IL-21) par les cellules du système immunitaire inné lors d’une infection ou d’une inflammation, ainsi que la présence constitutive d’IL-7, peuvent stimuler la prolifération et l’activation des lymphocytes T CD8 de façon non spécifique à l’antigène. Cette stimulation entraîne une augmentation de l’avidité fonctionnelle de leur TCR causant ainsi une forte prolifération ainsi que l’acquisition de fonctions effectrices spécifiques. Cette liaison entre le système immunitaire inné et adaptatif, médiée par les cytokines pro-inflammatoires et les cytokines homéostatiques joue un rôle très important dans l’élimination des pathogènes ainsi que dans le développement de maladies auto-immunitaires. / Abstract : Homeostasis of naive and memory CD8[superscript +] T lymphocytes is dependent on two cytokines IL-7 and IL-15, respectively. During an immune response to an infection, cells of the innate immune system produce several pro-inflammatory cytokines. We have observed that these two groups of cytokines, namely proinflammatory and homeostatic, can have a synergistic effect on CD8 T lymphocytes. Specifically, incubation of naive CD8 T cells with IL-6 or IL-21 in the presence of IL-7 or IL-15 induced strong proliferation in an antigen independent manner. While the combination of IL-6 or IL-21 with IL-15 induced strong proliferation of memory CD8 T cells, naïve CD8 T cells responded better to the combination with IL-7. These stimulatory cytokine combinations elicited strong STAT5 phosphorylation and it’s binding to DNA in CD8 T cells. We investigated the effect of priming CD8 T cells with the synergistic combination of IL-6 or IL-21 and IL-7 on their subsequent response to antigen. We observed that cytokine priming for only 24 hours enhanced their sensitivity to antigen, resulting in strong proliferation, effectors functions and cytotoxicity. These effects were observed with CD8 T cells expressing transgenic TCR with strong (P14) or weak (H-Y) affinity towards cognate peptide antigens. Priming CD8 T cells with the synergistic combination of cytokines increased the expression of IL-2 receptor gamma (CD132) and augmented the production of IL-2 when stimulated with antigen. These cells also expressed elevated levels of CD8 and CD45, as well as down modulate CD5, and these events may underlie the increased TCR avidity. Stimulation of CD8 T cells with the synergistic combination of cytokines induced phosphorylation of LAT and AKT. However, subsequent TCR stimulation did not further increase these phosphorylation events. We have observed that C D8 T cells primed with the synergistic combinations of cytokines up regulated CD62L, which could promote their migration through lymph nodes. In conclusion, inflammatory cytokines such as (IL-6, IL-15, IL-21) secreted by cells of the innate immune system during an infection or non-infectious inflammation, and basal levels of the homeostatic cytokine IL-7 can act in synergy with inflammatory cytokines to activate CD8 T lymphocytes in an antigen independent manner. This stimulation also results in an increase in the functional avidity of their TCR, as indicated by strong antigen responsiveness with increased proliferation and display of effectors functions. This connection between the innate and adaptive system mediated by inflammatory cytokines may play an important role in pathogen clearance and possibly in the development of autoimmune diseases.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Human γδ T cells expressing Vγ2Vδ2 TCRs monitor foreign- and self-prenyl pyrophosphate metabolites in isoprenoid biosynthesis to mediate immunity to microbes and tumors. Vγ2Vδ2 cells have been used for adoptive cancer immunotherapy with some partial and complete remissions. Most trials have used continuous zoledronate exposure to expand Vγ2Vδ2 cells. Zoledronate inhibits farnesyl pyrophosphate synthase causing isopentenyl pyrophosphate to accumulate that then stimulates Vγ2Vδ2 cells. Because zoledronate exposure is toxic, we hypothesized that a short period of exposure would reduce T cell toxicity but still be sufficient for monocytes uptake. Supporting this hypothesis, pulse zoledronate exposure with IL-2 resulted in more uniform expansion of Vγ2Vδ2 cells with higher purity and cell numbers as compared with continuous exposure. These Vγ2Vδ2 cells also had higher levels of CD107a and perforin and slightly increased tumor cytotoxicity. Importantly, adoptive immunotherapy with Vγ2Vδ2 cells derived by pulse stimulation controlled human PC-3 prostate cancer cells in immunodeficient NSG mice significantly better than those derived by continuous stimulation. Pulse zoledronate stimulation of Vγ2Vδ2 cells with IL-15 also resulted in higher purity and cell numbers. Like with CD8 αβ T cells, IL-15 preserved early memory Vγ2Vδ2 T cell subsets better than IL-2. However, despite this fact, adoptive immunotherapy with Vγ2Vδ2 cells derived with IL-15 showed similar inhibition of PC-3 tumor growth as those derived with IL-2. Thus, pulse zoledronate stimulation maximizes the purity, quantity, and quality of expanded Vγ2Vδ2 cells. This simple modification to existing protocols would likely enhance the effectiveness of adoptively transferred Vγ2Vδ2 T cells.

La stimulation de cellules T naïves nécessite du déclenchement de la signalisation par l'intermédiaire du récepteur d'antigène de cellule T (TCR) ainsi que l'activation simultanée des récepteurs de co-stimulation. Toutefois, les cellules T CD8+ naïves peuvent proliférer de façon antigène-indépendants suite à la stimulation synergique par certaines cytokines homéostatiques (IL-7 ou IL-15) et inflammatoires (IL-6 ou IL-21). Ces cellules pré-stimulées prolifèrent même à des faibles concentrations d'antigènes ou en présence d’agonistes du TCR. Ceci leur permet de sécréter des cytokines effectrices, d'être plus spécifiques à leur antigène et d’avoir une activité cytolytique plus importante. Les mécanismes déclenchés par les cellules T CD8+ permettant une sensibilité accrue à l'antigène suite à la "pré-stimulation aux cytokines" n'ont pas encore été élucidés. Nous avons utilisé trois différents modèles de souris transgéniques portant le TCR P14, PMEL ou 8.3-NOD sur les lymphocytes T CD8+ afin d’étudier les mécanismes moléculaires suite à la pré-stimulation aux cytokines. Les cellules T CD8+ portant le TCR transgénique amorcées avec les cytokines, possèdent une augmentation globale des protéines tyrosine-phosphorylés après stimulation du TCR par rapport aux cellules naïves. Cette augmentation de la phosphorylation de la protéine tyrosine a été associée à une augmentation de l'expression de CD8, et a été moins prononcé lorsque CD8 a également été réticulés avec le TCR. Ceci suggère que l'amorçage aux cytokines peut prédisposer le TCR et CD8 à colocaliser, ce qui renforcerait la phosphorylation des chaînes du TCR par la kinase Lck associée à CD8. Les lymphocytes T CD8+ amorcées aux cytokines présentent également des quantités accrues de radeaux lipidiques plasmatiques à la membrane, qui organisent la plate-forme de signalisation du TCR au cours de la stimulation antigénique. L’amorçage aux cytokines des lymphocytes T CD8+ a également augmenté la localisation de CD45, une phosphatase qui diminue l’inhibition automatique de la Lck dans les radeaux lipidiques. Cependant, l'amorçage aux cytokines n'a pas d'incidence sur la capacité des cellules CD8+ T pour former des conjugués avec les cellules présentatrices d'antigène puisées avec des peptides apparentés. En conclusion, ces résultats suggèrent que la composition et les fonctions des radeaux lipidiques peuvent moduler la sensibilité à l'antigène via le TCR lorsque les lymphocytes T CD8+ ont été pré-stimulés aux cytokines.

No description available.