IL-33 participa em diversas doenças com funções pró-inflamatórias e protetoras, de acordo com o contexto do microambiente. Com relação a biologia tumoral, o papel de IL-33 ainda é controverso. Estudos demonstraram que IL-33 possui efeitos pró e anti-inflamatórios em diferentes modelos animais de câncer. A presença desta citocina no estroma favorece a imunossupressão pela ativação de células T reguladoras e células mieloides supressoras. IL- 33 pode em outras situações promover a imunogenicidade e a resposta imune antitumoral de tipo 1 através das células T citotóxicas e células Natural Killers. Contudo o efeito preciso de IL-33 em diferentes tipos de câncer permanece incerto. Sendo assim, compreender o papel de IL-33 na imunobiologia do câncer, poderia direcionar esta citocina como um possível alvo em imunoterapias contra o câncer. Considerando, portanto, a pluralidade desta citocina no desenvolvimento de uma resposta imune, no presente estudo buscamos avaliar os efeitos do tratamento com anti-IL-33 em modelo experimental de carcinoma espinocelular de pele em camundongos BALB/c de linhagem selvagem. Ao final dos protocolos de indução e tratamento, a análise histopatológica revelou que o tratamento com anti-IL-33 levou a menor incidência de carcinoma espinocelular in situ e diminuição das atipias celulares e, consequentemente, do grau de displasia. O tratamento com anti-IL-33 levou a aumento nos percentuais de células B e diminuição nas percentagens de linfócitos T CD4+, células dendríticas, células TREG e macrófagos isolados do microambiente tumoral. Ademais, o tratamento com anti-IL-33 levou a aumento na percentagem de linfócitos T CD4+ produtores de IFN- e menor percentagem de linfócitos T CD4+ e CD8+ produtores de IL-4 nos linfonodos. Em camundongos submetidos ao tratamento, observou-se menor produção de TGF- no microambiente tumoral, sem interferir de modo significativo com a produção de IFN-, IL-4, IL-10 e IL-17. Os nossos resultados indicam que o tratamento com anti-IL-33 poderia ser alvo de novos estudos em busca de estratégias terapêuticas para o carcinoma espinocelular de pele. / IL-33 participates in several diseases with pro-inflammatory and protective functions, according to the context of the microenvironment. Related to tumor biology, the role of IL-33 is still controversial. Studies have shown that IL-33 has pro and anti-inflammatory effects in different animal models of cancer. Its presence in the stromal and tumor serum increases the immunosuppression by the activation of regulatory T cells and myeloid-derived suppressor cells. On the other hand, the intracellular form in tumor cells promotes immunogenicity and the antitumor type 1 immune response through cytotoxic T cells and natural killer cells. However, the precise effect of IL-33 on cancer conditions remains uncertain. Thus, understanding its role in the immunobiology of cancer could target this cytokine as a marker in cancer immunotherapies. Considering, the range of IL-33 in the development of an immune response, this study aims to evaluate the effects of the anti-IL-33 treatment on wild type BALB/c mouse squamous cell carcinoma (SSCC) development. Histopathological analysis revealed that anti-IL-33 treatment decreased the dysplasia. In addition, anti-IL-33 treatment showed an increasing percentage of B cells and reduced the percentage of CD4+ T lymphocytes, dendritic cells, TREG cells and macrophages in the tumor microenvironment. In the lymph node, anti-IL-33 treatment induced a shift towards the TH1 type cytokine profile and reduced the percentage of IL-4 expressing CD4+ and CD8+ cells. Additionally, anti-IL-33 treatment showed a reduced TGF- production in the tumor microenvironment, but with no changes to the IFN-, IL-4, IL-10 e IL-17 production. Taken together these results indicate that anti-IL-33 treatment could be the subject of further studies of therapeutic strategies for squamous cell carcinoma of the skin.

O carcinoma espinocelular (CEC) é um dos cânceres humanos mais incidentes. A despeito do entendimento da fisiopatologia do CEC, as opções terapêuticas ainda são limitadas e o(s) exato(s) mecanismo(s) envolvido(s) na progressão deste tipo de tumor ainda não foi descrito. Estudos recentes mostram a existência de uma associação direta entre a resposta imune TH1 e um melhor prognóstico em pacientes com CEC. Aumento da expressão de componentes do eixo IL-33/ST2 foi demonstrado contribuir para transformação neoplásica em diversos modelos tumorais, incluindo cânceres de estômago e de mama. Trabalho recente do nosso e de outros laboratórios indicam que IL-33 pode impedir a resposta imune TH1 . Baseado nessas observações, a hipótese testada foi que o impedimento da resposta imune pela interação IL-33/ST2 pode contribuir para iniciação e progressão do CEC. Utilizando modelo de carcinogênese química em camundongos WT e deficientes de ST2 (ST2KO), os resultados mostram que a deficiência de ST2 leva a uma notável redução da severidade das lesões 20 semanas após a carcinogênese química, sugerindo que a sinalização ST2 é necessária para o desenvolvimento tumoral neste modelo. Análises do infiltrado inflamatório presente nas lesões em camundongos WT e ST2KO revelaram redução significativa nas percentagens de macrófagos, células T CD4+ e células dendríticas, mas não em células T CD8+, células B e células natural killer (NK) no microambiente tumoral de camundongos ST2KO. Além disso, células NK esplênicas isoladas de camundongos ST2KO exibiram atividade citotóxica aumentada contra células YAC quando comparado com células de camundongos do grupo controle (WT). Os resultados indicam que a via IL-33/ST2 contribui para o desenvolvimento de carcinoma espinocelular recrutando células T CD4+, macrófagos e células dendríticas e reduzindo a citotoxicidade de células NK. / Squamous cell carcinoma (SCC) is the second most common form of skin cancer and is most commonly observed in photo-exposed areas of the body. The mechanism(s) involved in the progression of this tumor are unknown. Recent studies have shown that there is a direct association between a TH1-related immune response and a better prognosis in patients with SCC. Increased expression of the IL33/ST2 axis components has been demonstrated to contribute to neoplastic transformation in several tumor models, including gastric and breast cancer. Recent work from ours and other laboratories indicate that can IL-33 impair TH1-type immune responses. Based on these observations, we hypothesized that TH1-type immune response impairment by IL33/ST2 could contribute to the initiation and progress SCC. We found that ST2 deficiency led to a marked decreased in severity of skin lesions at 20 weeks post-DMBA, suggesting that ST2 signaling is necessary for tumor development in this model. Analysis of tumor lesions in WT and ST2KO mice revealed that lack of ST2 led to a specific and significant reduction in the frequency of macrophages, T CD4+ and dendritic cells, but not CD8+, B and NK cells. In addition, splenic NK cells isolated from DMBA-treated ST2KO mice exhibited increased cytotoxicity activity against YAC cells targets when compared with WT splenic NK cells in the same cytotoxic assay. Altogether, our findings indicate that IL-33/ST2 pathway contributes to the SCC development by recruitment T CD4+ cells, macrophages, and dendritic cells and impairing NK cytotoxicity.

Les vascularites des gros vaisseaux comprennent principalement la maladie de Takayasu et l'artérite à cellules géantes. Elles sont caractérisées par des lésions inflammatoires artérielles, associées à une néo-vascularisation adventitielle importante, une désorganisation architecturale de la paroi artérielle et des lésions fibrotiques, affectant l’aorte et ses principales branches. Ces maladies sont caractérisées par des réponses lymphocytaires Th1 et Th17 excessives et dérégulées. Actuellement, les mécanismes régulant la différenciation lymphocytaire, la réponse endothéliale et l’homéostasie tissulaire en contexte d’inflammation artérielle chronique ne sont pas suffisamment connus. Dans la 1ère partie de nos travaux, nous avons étudié le rôle de l’IL-33, cytokine sécrétée par les cellules endothéliales en cas de nécrose tissulaire, surexprimée dans les vascularites des gros vaisseaux et impliquée dans la régulation de la réponse immune. Nous avons mis en évidence le rôle immunomodulateur de l’IL-33 dans les vascularites des gros vaisseaux. Cette cytokine favorise en effet directement une différenciation Th2 et une augmentation des lymphocytes T régulateurs (Treg). L’IL-33 exerce également son action immunorégulatrice par le biais des mastocytes qui favorisent également une augmentation majeure des Treg en présence d’IL-33, probablement grâce à la sécrétion d’IL-2, essentielle à la survie et l’expansion des Treg et la sécrétion d’indoléamine 2,3 dioxygénase (IDO). L’IL-33 et les mastocytes ont également un rôle paradoxal en contexte inflammatoire, en favorisant les processus de néo-angiogenèse, d’activation endothéliale et d’augmentation de la perméabilité vasculaire, phénomènes participant au recrutement de cellules inflammatoires sur le site lésionnel. L’axe IL-33/ST2 et les mastocytes, via leurs actions pro-Th2, immunorégulatrice, et pro-angiogénique, sont également associés aux processus de réparation tissulaire, qui pourraient s’avérer délétères en cas d’inflammation persistante, en raison du développement de lésions de fibrose. Si l’IL-33 ne semble pas être directement responsable d’une activation ou d’une prolifération fibroblastique au niveau artériel, les mastocytes activés par du sérum de patients ayant une vascularite des gros vaisseaux conduisent en revanche à des modifications du phénotype fibroblastique et induisent une augmentation de production de collagène de type 1 et de fibronectine.Dans la 2ème partie de nos travaux, nous avons mis en évidence des profils de différenciation distincts des lymphocytes T CD4+ dans la maladie de Takayasu et l’artérite à cellules géantes. Nous avons démontré une augmentation des lymphocytes T folliculaires helper (Tfh) circulants dans la maladie de Takayasu. L’augmentation des Tfhc chez les patients ayant une maladie de Takayasu est associée à une augmentation des lymphocytes B circulants et à la présence d’organes lymphoïdes ectopiques aortiques. Les Tfhc des patients Takayasu gardent les propriétés fonctionnelles des lymphocytes Tfh tissulaires, puisqu’ils favorisent la prolifération des lymphocytes B ainsi que leur différenciation en cellules mémoires. Nos résultats suggèrent donc l’implication d’une coopération lymphocytaire B et T centrale dans la physiopathologie de la maladie de Takayasu, qui pourrait être associée à la présence de lymphocytes B auto-réactifs sécrétant des auto-anticorps. / Large vessel vasculitis (LVV) mainly include Takayasu arteritis (TA) and giant cell arteritis (GCA), which are characterized by arterial inflammatory lesions, associated with adventitial neo-angiogenesis and fibrotic lesions. They predominantly involve aorta and its major branches. These diseases are related to unbalanced Th1 and Th17 immune responses. The mechanisms regulating lymphocyte differentiation, endothelial response and tissue homeostasis in arterial inflammatory diseases are not sufficiently known. First, we have studied the role of IL-33, which is a cytokine secreted by endothelial cells in response to tissue necrosis and is involved in the regulation of immune response. We demonstrated the immunomodulatory impact of IL-33 and mast cells in LVV. IL-33 had a direct immunomodulatory impact by increasing Th2 and regulatory T cells in PBMC. IL-33 and MC further enhanced Th2 and regulatory responses by inducing a 6.1 fold increased proportion of Tregs through increased indoleamine 2 3-dioxygenase (IDO) and IL-2 secretion. IL-33 and mast cells also had a paradoxical impact in LVV, by promoting angiogenesis, endothelial activation and vascular permeability. IL-33 and mast cells, through Th2 and regulatory responses and angiogenesis, were associated with tissue repair and arterial fibrosis. Although IL-33 did not appear to directly lead to arterial fibroblast activation and proliferation, mast cells activated by LVV serum induced increased production of type 1 collagen and fibronectin by arterial fibroblasts. In the second part of our work, we have demonstrated distinct differentiation profiles of CD4 + T cells in TA and GCA. We demonstrated an increase in circulating T follicular helper lymphocytes (cTfh), defined as CXCR5+ CD4+ T cells, in TA. The increase of cTfh was associated with an increase in circulating B lymphocytes and the presence of tertiary lymphoid organs in TA aorta. CXCR5+ CD4+ T cells of TA patients helped B cells to differentiate into memory cells, to proliferate and to secrete type G immunoglobulins. Our data provide evidence of the key coordinated role of Tfh and B cells in tertiary lymphoid structures in TA and suggest an antigenic trigger.

La modification post-traductionnelle des chimiokines par la dipeptidyl peptidase-4 (DPP4 ou CD26) régule négativement le trafic des lymphocytes, et son inhibition améliore la migration des lymphocytes T et l'immunité anti-tumorale en préservant la forme fonctionnelle de CXCL10. En étendant ces résultats initiaux aux humains et à un modèle préclinique de carcinome hépatocellulaire, nous avons découvert un nouveau mécanisme par lequel l'inhibition de DPP4 améliore les réponses anti-tumorales par le recrutement des éosinophiles. Plus précisément, l'administration d'inhibiteurs de DPP4 (DPP4i) conduit à des concentrations tumorales plus élevées de CCL11 (ou eotaxine) et à une augmentation de la migration des éosinophiles exprimant CCR3 dans les tumeurs. Un meilleur contrôle de la croissance tumorale a été observé lors du traitement par DPP4i, un effet conservé chez les souris Rag2–/– mais abrogé uniquement lors de la déplétion des éosinophiles ou de l'inhibition de leur dégranulation. Nous avons également démontré que l'expression tumorale d’IL-33 était nécessaire et suffisante pour une réponse anti-tumorale médiée par les éosinophiles et que ce mécanisme contribuait à l'efficacité des inhibiteurs de points de contrôle immunitaires. Ces résultats révèlent un nouveau mécanisme par lequel le contrôle tumoral est médiée par IL-33 et les éosinophiles, mécanisme ici révélé lorsque les mécanismes endogènes de régulation immunitaire par DPP4 sont inhibés. / Dipeptidyl peptidase-4 (DPP4 or CD26)–mediated post-translational modification of chemokines has been shown to negatively regulate lymphocyte trafficking, and its inhibition enhances T cell migration and tumor immunity by preserving functional CXCL10. In extending these initial findings to humans and pre-clinical hepatocellular carcinoma models, we discovered a new mechanism whereby DPP4 inhibition improves anti-tumor responses by eosinophil recruitment. Specifically, administration of DPP4 inhibitors (DPP4i) resulted in higher concentrations of CCL11 (or eotaxin) and increased CCR3-mediated eosinophil migration into mouse tumors. Enhanced tumor control was observed upon treatment with DPP4i, an effect strikingly preserved in Rag2–/– mice, and abrogated only upon depletion of eosinophils or inhibition of their degranulation. We further demonstrated that tumor expression of IL-33 was necessary and sufficient for eosinophil-mediated anti-tumor responses, and that this mechanism contributed to checkpoint inhibitor efficacy. These findings provide new insight into IL-33- and eosinophil-mediated tumor control, revealed when endogenous mechanisms of DPP4 immune regulation are inhibited.

O carcinoma espinocelular (CEC) é um dos cânceres humanos mais incidentes. A despeito do entendimento da fisiopatologia do CEC, as opções terapêuticas ainda são limitadas e o(s) exato(s) mecanismo(s) envolvido(s) na progressão deste tipo de tumor ainda não foi descrito. Estudos recentes mostram a existência de uma associação direta entre a resposta imune TH1 e um melhor prognóstico em pacientes com CEC. Aumento da expressão de componentes do eixo IL-33/ST2 foi demonstrado contribuir para transformação neoplásica em diversos modelos tumorais, incluindo cânceres de estômago e de mama. Trabalho recente do nosso e de outros laboratórios indicam que IL-33 pode impedir a resposta imune TH1 . Baseado nessas observações, a hipótese testada foi que o impedimento da resposta imune pela interação IL-33/ST2 pode contribuir para iniciação e progressão do CEC. Utilizando modelo de carcinogênese química em camundongos WT e deficientes de ST2 (ST2KO), os resultados mostram que a deficiência de ST2 leva a uma notável redução da severidade das lesões 20 semanas após a carcinogênese química, sugerindo que a sinalização ST2 é necessária para o desenvolvimento tumoral neste modelo. Análises do infiltrado inflamatório presente nas lesões em camundongos WT e ST2KO revelaram redução significativa nas percentagens de macrófagos, células T CD4+ e células dendríticas, mas não em células T CD8+, células B e células natural killer (NK) no microambiente tumoral de camundongos ST2KO. Além disso, células NK esplênicas isoladas de camundongos ST2KO exibiram atividade citotóxica aumentada contra células YAC quando comparado com células de camundongos do grupo controle (WT). Os resultados indicam que a via IL-33/ST2 contribui para o desenvolvimento de carcinoma espinocelular recrutando células T CD4+, macrófagos e células dendríticas e reduzindo a citotoxicidade de células NK. / Squamous cell carcinoma (SCC) is the second most common form of skin cancer and is most commonly observed in photo-exposed areas of the body. The mechanism(s) involved in the progression of this tumor are unknown. Recent studies have shown that there is a direct association between a TH1-related immune response and a better prognosis in patients with SCC. Increased expression of the IL33/ST2 axis components has been demonstrated to contribute to neoplastic transformation in several tumor models, including gastric and breast cancer. Recent work from ours and other laboratories indicate that can IL-33 impair TH1-type immune responses. Based on these observations, we hypothesized that TH1-type immune response impairment by IL33/ST2 could contribute to the initiation and progress SCC. We found that ST2 deficiency led to a marked decreased in severity of skin lesions at 20 weeks post-DMBA, suggesting that ST2 signaling is necessary for tumor development in this model. Analysis of tumor lesions in WT and ST2KO mice revealed that lack of ST2 led to a specific and significant reduction in the frequency of macrophages, T CD4+ and dendritic cells, but not CD8+, B and NK cells. In addition, splenic NK cells isolated from DMBA-treated ST2KO mice exhibited increased cytotoxicity activity against YAC cells targets when compared with WT splenic NK cells in the same cytotoxic assay. Altogether, our findings indicate that IL-33/ST2 pathway contributes to the SCC development by recruitment T CD4+ cells, macrophages, and dendritic cells and impairing NK cytotoxicity.

A rinossinusite crônica (RSC) é uma doença inflamatória da mucosa nasal, e pouco tem sido relacionada à exposição no ambiente de trabalho, em especial ao algodão. Atualmente, uma série de citocinas e quimiocinas tem sido estudada para elucidação das características imunológicas que levam ao desenvolvimento da doença. Objetivos: Caracterizar a exposição ao algodão como indutora de RSC e determinar o padrão de resposta inflamatória imuno-histoquímica da mucosa nasal de indivíduos expostos ou não ao algodão e que desenvolveram RSC. Casuística e Metodos: Por meio de questionário baseado no EPOS e SNOT-22 foi realizado diagnóstico clínico de RSC em indivíduos expostos ao algodão no ambiente de trabalho. Após a confirmação diagnóstica com tomografia computadorizada e nasofibroscopia flexível foi realizada biópsia na mucosa de concha média de pacientes com diagnóstico clínico de RSC para análise da expressão de IL-4, IL-5, IL-10, IL-17 e IL-33. A análise foi realizada também em grupo com RSC sem exposição ao algodão e controle sem RSC. Resultados: Todos os indivíduos expostos ao algodão com sintomatologia sugestiva de RSC apresentaram padrão histológico com aumento da expressão de IL-4, IL-5, IL-10, IL-17 e IL-33. Conclusões: O presente estudo comprovou a estreita relação entre a exposição ao algodão no ambiente de trabalho e o surgimento de uma resposta inflamatória com aumento da expressão das interleucinas estudadas. A possível instituição de terapias/medicamentos que inibissem a expressão dessas citocinas poderia auxiliar na diminuição do processo inflamatório presente na RSC e/ou no desencadeamento da doença / The chronic rhinusinusitis (CRS) is an inflammatory disease of the nasal mucosa, and has been little related to exposure in the work environment, especially to cotton. Currently, a number of cytokines and chemokines have been studied to elucidate the immunological characteristics that lead to the development of the disease. Objectives: To characterize exposure to cotton as an inducer of CRS and to determine the pattern of inflammatory immune-histochemical response of the nasal mucosa of individuals exposed or not to cotton and who developed CRS. Casuistic and Methods: Using a questionnaire based on EPOS and SNOT-22, a clinical diagnosis of CRS was performed in individuals exposed to cotton in the work environment. After diagnostic confirmation with computed tomography and flexible nasofibroscopy, biopsy was performed on the middle concha mucosa of patients with clinical diagnosis of CRS to analyze the expression of IL-4, IL-5, IL-10, IL-17 and IL- 33. The analysis was also performed in a group with CRS without exposure to cotton and control without CRS. Results: All individuals exposed to cotton with symptoms suggestive of CRS had a histological pattern with increased expression of IL-4, IL-5, IL-10, IL-17 and IL-33. Conclusions: This study confirms the close relationship between exposure to cotton in the workplace and the appearance of an inflammatory response with increased expression of interleukins studied. The possible institution of therapies / drugs that inhibit the expression of these cytokines could help in the reduction of the inflammatory process present in CRS and in the onset of the disease

Les traitements actuels de la leucémie myéloïde chronique (LMC) ne permettent pas d’éliminer la totalité des cellules leucémiques. Dans le but de développer un traitement curatif, il est donc nécessaire de parvenir à une meilleure compréhension des mécanismes sous-jacents des réponses partielles aux traitements, Dans ce travail, nous avons postulé qu’il existe des mécanismes de contrôle extrinsèques de la LMC pouvant influencer l’efficacité des différents traitements. Nous avons choisi d’étudier le rôle potentiel dans la LMC des lymphocytes iNKT, cellules T de type « inné » auxquelles la littérature attribue de nombreuses fonctions antitumorales et des facteurs moléculaires, la cytokine/alarmine IL-33, produite dans la niche hématopoïétique, et son récepteur ST2 à la surface des cellules hématopoïétiques comme cibles de l’IL-33.La première partie de notre travail a ainsi permis de mettre en évidence de profondes altérations fonctionnelles des lymphocytes iNKT chez les patients atteints de LMC ainsi qu’une correction partielle de ces défauts après traitement par l’Imatinib (IM) ou l’IFN-. L’ensemble de ces résultats permet de proposer que l’altération des fonctions des cellules iNKT au cours du développement de la LMC pourrait participer aux mécanismes d’échappement de la tumeur au contrôle par le système immunitaire. La deuxième partie de notre travail a permis de mettre en évidence une expression de la molécule ST2, chaîne spécifique du récepteur à l’IL-33, à la surface des cellules CD34+ de patients atteints de LMC, expression non décelée chez les sujets sains et les patients en rémission après traitement par l’IM. De plus, contrairement aux cellules CD34+ de sujets sains, les cellules progénititrices de patients en phase chronique prolifèrent en réponse à l’IL-33. Enfin, nous avons montré que l’IL-33 est capable de contrecarrer in vitro les effets antiprolifératifs de l’IM. Ainsi nous pouvons émettre l’hypothèse selon laquelle l’IL-33, une cytokine/alarmine, puisse participer aux phénomènes conduisant à la persistance de progéniteurs hématopoïétiques leucémiques chez les patients sous traitement par IM. / To date, treatment of Chronic Myeloid Leukaemia (CML) is not sufficient to completely eradicate leukaemia cells. Hence, in order to develop a curative treatment, it is necessary to have a better understanding of the underlying mechanisms explaining why response to treatment is only partial..We therefore addressed the question whether the extrinsic mechanisms of CML control can affect the effectiveness of different treatments. We first provided evidence of profound functional impairments of iNKT cells in patients with CML. Interestingly these impairments were partially corrected after treatment with Imatinib (IM) or IFN-. Consequently our results suggest that altered functions of iNKT cells during the development of CML could facilitate tumour escape from immune destruction. . The second part of our work revealed that CD34+ progenitors from CML patients upregulate their cell surface expression of the IL-33-specific receptor chain ST2, proliferate and produce cytokines in response to IL-33, conversely to CD34+ cells from healthy individuals. Moreover, ST2 overexpression is normalized following IM therapy, while IL-33 counteracts in vitro IM-induced growth arrest in CML CD34+ progenitors. From these findings, it can be surmised that IL-33, a cytokine/alarmin likely expressed in the hematopoietic niche, facilitates the development of CML and IM resistance.

L'interleukine-33 (IL-33) est une alarmine appartenant à la famille de l'IL-1. Elle est rapidement libérée lors de stress cellulaires et participe ainsi à la réponse immunitaire en cas de danger. L'IL-33 est une cytokine pléïotrope (réponses immunitaires de type 2 dans l'allergie et les infections parasitaires et de type 1 dans les infections virales, participation à la réponse inflammatoire et à la réparation tissulaire) et son rôle dans les cancers est controversé. Nous avons émis l'hypothèse que des signaux de stress présents dans une tumeur pourraient conduire à la sécrétion de l'IL-33, qui pourrait alors jouer un rôle important dans l'activation de la réponse immunitaire dans les cancers. Dans un premier temps, nous avons montré que l'IL-33 est exprimée dans le stroma des cancers du sein, en particulier de type luminal. Plus précisément, elle est retrouvée dans le noyau des cellules endothéliales et le cytoplasme des fibroblastes et des macrophages. Les mécanismes conduisant à la sécrétion de l'IL-33 au sein des tumeurs sont en cours d'évaluation. Dans un second temps, nous avons montré qu'en combinaison avec l'IL-12, l'IL-33 potentialise les fonctions sécrétoires (notamment l'IFN-?) et cytotoxiques des cellules NK, douées de propriétés anti-tumorales. En effet, l'IL-12 induit l'expression de ST2, le récepteur de l'IL-33, sélectivement à la surface des cellules NK CD56dim, les sensibilisant ainsi à l'IL-33. En comparant l'IL-33 aux membres clés de la famille de l'IL-1, nous avons montré que contrairement à l'IL-33, i) l'IL-1a/ß activent uniquement les cellules NK CD56bright exprimant constitutivement IL-1RI et ii) l'IL-18 stimule fortement les fonctions des deux sous-populations de cellules NK qui expriment l'IL18R à l'état basal. En conclusion, nos résultats pourraient suggérer un rôle anti-tumoral potentiel de l'IL-33 via l'activation des cellules NK et ouvrent sur des stratégies thérapeutiques basées sur l'activation des cellules NK dans les cancers / IL-33 is an alarmin which belongs to the IL-1 family. Upon cellular stress, IL-33 is rapidly released and contributes to the activation of the immune system in case of danger. IL-33 has pleiotropic effects (type 2 immune responses in allergic disease or parasitic infection, type 1 immune responses in viral infection, participation to the inflammatory response and to tissue remodeling and repair) and its role in cancer is controversial. We hypothesize that upon stress related to tumor development, IL-33 could be released and activate immune responses in tumors. First, we showed that IL-33 is expressed in the stroma of breast tumors, in particular in luminal subtype. More precisely, IL-33 is expressed in the nucleus of endothelial cells and in the cytoplasm of fibroblasts and macrophages. The mechanisms responsible for IL-33 release in tumor are under investigation. Then, we demonstrated that IL-33 combined to IL-12 potentiates the secretory (particularly IFN-?) and cytotoxic functions of NK cells, which possess anti-tumoral properties. IL-12 induces ST2 (IL-33 receptor) expression selectively on CD56dim NK cells, making them sensitive to IL-33 stimulation. By comparing IL-33 to key members of the IL-1 family, we showed that in contrast to IL -33, i) IL-1a/ß activate only CD56bright NK cells, which express constitutively IL-1R and ii) IL-18 strongly activates both subsets of NK cells which express constitutively high levels of IL-18R. In conclusion, our results could support a potential anti-tumoral role of IL-33 via NK cell activation and offer new therapeutic opportunities based on NK cell activation in cancer

Les lésions du système nerveux central (SNC) entraînent une perte neuronale associée à des déficits fonctionnels importants. En réponse à une lésion, les capacités de repousse axonale et de régénération spontanée des neurones du SNC sont limitées. Nous avons évalué, dans un modèle de lésion corticale chez la souris adulte, le potentiel des greffes de neurones corticaux embryonnaires à réparer les voies corticales lésées. L'efficacité de cette approche thérapeutique dépend (1) du degré de survie des cellules greffées, (2) de la capacité des cellules greffées à se différencier en type neuronal approprié et (3) de la capacité des neurones greffés à restaurer les voies corticales endommagées de façon spécifiques. Nous avons montré que les neurones embryonnaires corticaux d'origine du cortex moteur transplantés immédiatement après la lésion du cortex moteur adulte se différencient en neurones matures exprimant les mêmes neurotransmetteurs et marqueurs de couches corticales que ceux du cortex normal. De plus, les neurones transplantés développent des projections vers les cibles corticales et sous corticales appropriées. Par ailleurs, nous avons étudié l'influence de la neuroinflammation post-lésionnelle sur la survie des neurones transplantés et, l'influence des neurones transplantés sur la neuroinflammation de l'hôte. / Central nervous system (CNS) lesions leads to a neuronal loss associated with significant functional deficits. In response to injury, the capacity of spontaneous axonal regrowth and regeneration of neurons in the CNS are limited. We evaluated in a model of cortical lesion in adult mice, the potential of embryonic cortical neurons grafts to repair the injured cortical pathways. The efficacy of this therapeutic approach depends on (1) the degree of survival of transplanted cells, (2) the ability of the grafted cells to differentiate into neuronal appropriate type and (3) the ability of the transplanted neurons to restore damaged cortical pathways. We have shown that embryonic cortical neurons transplanted immediately after the injury of the adult motor cortex differentiate into mature neurons expressing the same neurotransmitters and markers of cortical layers that are normally expressed by intact cortex. Furthermore, the transplanted neurons develop projections to the appropriate cortical and sub-cortical targets. Furthermore, we studied the influence of post-traumatic neuroinflammation on the survival of transplanted neurons and the influence of transplanted neurons on host neuroinflammation.

Des études menées au laboratoire avaient démontré un rôle critique de l’inflammasome NLRP3 dans l’asthme allergique en réponse à l’ovalbumine en absence d’adjuvant. Mes travaux de thèse ont porté sur le rôle de NLRP3 et de la caspase-1 dans un modèle murin d’inflammation pulmonaire induite par l’allergène d’acarien HDM. Nous avons montré un rôle régulateur de la caspase-1 dépendant de l’inflammasome NLRP3 et la molécule adaptatrice ASC mais pas de l’inflammasome NLRC4. Cette régulation de la réponse allergique se caractérise par une augmentation de l’infiltration des éosinophiles, de l’hyperréactivité bronchique et de la production des cytokines de type Th2 telles que l’IL-4, l’IL-5, l’IL-13 et l’IL-33 dans les poumons. Nous avons montré que les mécanismes responsables de cette régulation sont associés à l’IL-33 produite par les macrophages et que la neutralisation de l’IL-33 par administration locale de la protéine de fusion au récepteur ST2 (muST2-Fc) atténue les caractéristiques de l’asthme allergique. Ces résultats suggèrent que l’activation de la caspase-1 réduit la production d’IL-33 in vivo et régule ainsi la réponse l’inflammation pulmonaire induite par HDM et la réponse Th2. D’autre part, nous nous sommes intéressés au rôle de la Protéine Kinase C thêta (PKC-θ) dans ce même modèle d’inflammation pulmonaire. Nous avons démontré que PKC-θ joue non seulement un rôle protecteur dans l’asthme allergique mais également un rôle critique pour la prolifération et l’activation des cellules lymphoïdes innées (ILC2). D’autre part, l’inhibition de PKC-θ in vivo par administration orale de son inhibiteur spécifique C20 (BIX02656) atténue l’inflammation pulmonaire et la production d’IL-5 et d’IL-13. Nous suggérons que PKC-θ est impliquée dans la différenciation des Th2 et des ILC2 via un mécanisme dépendant des facteurs de transcription IRF4 et NFAT-1. Au total, mes travaux de thèse mettent en exergue deux molécules IL-33 et PKC-θ qui pourraient constituer des cibles thérapeutiques potentielles. / Studies from our laboratory have shown a critical role of NLRP3 inflammasome in response to ovalbumin allergen. In the present study we investigate the role of NLRP3 and caspase-1 in a mouse model of pulmonary inflammation induced by HDM. We have shown a regulatory role of caspase-1 dependant of the NLRP3 inflammasome and the adaptator molecule ASC but not NLRC4. The regulation of the allergic response is characterized by an increase of eosinophilia, bronchial hyperreactivity and Th2 cytokines production (IL-4, IL-5, IL-13 and IL-33) in lungs. We have shown that mechanisms responsible of this regulation are associated with IL-33 production by macrophages and that neutralization of IL-33 by local administration of a fusion protein of the ST2 receptor (muST2-Fc) reduce characteristics of asthma. These results suggest that caspase-1 activation reduce IL-33 production in vivo regulating lung inflammation and Th2 response induced by HDM. Moreover, we investigate the role of the Protein Kinase C theta (PKC-θ) in allergic airway inflammation. We have demonstrated that PKC-θ plays a protective role in allergic asthma but is critical for the activation and proliferation of innate lymphoid cells (ILC2). In addition, in vivo inhibition by oral administration of PKC-θ specific inhibitor C20 (BIX02656) reduces pulmonary inflammation with IL-5 and IL-13 production. We suggest that PKC-θ is implicated in Th2 and ILC2 differenciation by a mechanism dependant on transcription factors IRF4 and NFAT-1. Finally, my thesis projects describe IL-33 and PKC-θ as potential therapeutic targets for allergic lung inflammation.