Introdução: A rinite alérgica (RA) e a rinossinusite crônica (RSC) são doenças inflamatórias nasais com prevalência alta e crescente. Estima-se que 15,5% dos norte-americanos tenham RSC, e estudo recente encontrou prevalência de 5,51% na cidade de São Paulo, enquanto a RA acomete entre 10 e 20% da população mundial. Apesar de terem mecanismos fisiopatológicos distintos, em ambas, há recrutamento de células de defesa, principalmente linfócitos T, e produção de citocinas inflamatórias. Esses mediadores variam não apenas entre as doenças, mas também entre as populações acometidas, e seu conhecimento é importante para o diagnóstico correto e direcionamento da terapia escolhida. Objetivos: Mapear os mediadores inflamatórios presentes no lavado nasal e no condensado do ar exalado na RSC e na RA, avaliando possíveis biomarcadores da doença, e analisar o endotipo inflamatório dos pacientes estudados. Além disso, avaliar a qualidade de vida, o nível de obstrução nasal, a qualidade do sono dos pacientes afetados, o transporte mucociliar e coletar material para análise de pH, contagem de células totais e seu diferencial. Pacientes e métodos: Estudo exploratório prospectivo em corte transversal, sendo os pacientes divididos em quatro grupos: 1) Grupocontrole com pacientes sem queixas; 2) Pacientes com RA com prick test positivo; 3) Pacientes com RSC com polipose; e 4) Pacientes com RSC sem polipose. Todos os pacientes responderam a quatro questionários: 20-Item Sino-Nasal Outcome Test (SNOT-20p), Nasal Obstruction Symptom Evaluation (NOSE), o Índice de Qualidade do Sono de Pittsburgh (Pittsburgh Sleep Quality Index - PSQI-BR) e o questionário para triagem e diagnóstico da asma da European Community Respiratory Health Survey (ECRHS). Foi realizado exame físico, incluindo endoscopia nasal (escore de Lund- Kennedy modificado) e, nos pacientes com RSC, avaliação da tomografia computadorizada (TC) de face (escore de Lund-Mackay). Foi também avaliado o transporte mucociliar por meio do teste da sacarina. Coletou-se o condensado do ar exalado para análise do pH e lavado nasal para avaliação do pH, da presença de citocinas e da celularidade (total e diferencial). Foi avaliada a presença de IL-4, IL-5, IL-8, IL-17A, IL-22, TNF-Alfa e IFN-Gama no lavado nasal e IL-5, IL-17A, IL-22 e IFN-Gama no condensado do ar exalado. Resultados: Os pacientes com RSC apresentaram escores significativamente piores nos questionários de obstrução nasal (NOSE, p < 0,01) e qualidade de vida (SNOT-20p, p < 0,01) quando comparados aos controles, e tanto os pacientes com RSC quanto com RA apresentaram pior qualidade do sono (PSQI-BR, p < 0,01). O escore de extensão de Lund- Mackay foi mais elevado nos pacientes com RSC com polipose (p < 0,02). O teste da sacarina apresentou tempo mais prolongado no grupo RSC com polipose (p < 0,01). O pH do condensado do ar exalado não diferiu entre os grupos. O grupo RSC com polipose apresentou tanto diferença do pH (p < 0,01) quanto da contagem de células totais do lavado nasal (p < 0,01) quando comparado ao grupo-controle, porém sem diferença na contagem diferencial. IFN? do condensado foi mais elevado no grupo RA em comparação ao grupo C (p=0,05), enquanto IL-5 foi mais alto no grupo RSC com polipose quando comparado ao grupo RSC sem polipose (p=0,02). Os pacientes foram, então, divididos em endotipos, segundo os grupos descritos por Tomassen et al., sendo que endotipos são os subtipos da doença definidos funcionalmente e patologicamente por mecanismos moleculares distintos. Conclusão: Pacientes com RSC apresentaram escores piores nos questionários de qualidade de vida (SNOT-20p e NOSE), o que, em parte, poderia ser atribuído à pior qualidade do sono apresentada tanto por estes pacientes quanto pelos portadores de RA. O teste da sacarina evidenciou pior transporte mucociliar nos pacientes com RSC com polipose. Não houve diferença do pH do condensado do ar exalado, sugerindo que, apesar de interessante na avaliação das vias aéreas inferiores, este pode não ser um bom teste para análise das vias aéreas superiores. Foram encontradas alterações significantes tanto do pH quanto da contagem de células totais do lavado nasal do grupo com RSC com polipose, sem, no entanto, haver diferença na contagem diferencial. Dos 17 pacientes com RSC com perfil completo de citocinas, 12 se encaixam em endotipos já descritos, sendo que, dos cinco restantes, dois apresentam o mesmo perfil, podendo indicar um novo subgrupo / Introduction: Allergic rhinitis (AR) and chronic rhinosinusitis (CRS) are nasal inflammatory diseases with high and increasing prevalence. It is estimated that 15.5% of Americans have CRS, and a recent study found a prevalence of 5.51% in the city of São Paulo, while AR affects between 10 and 20% of the world population. Although they have distinct pathophysiological mechanisms, in both there is recruitment of defense cells, mainly T lymphocytes, and production of inflammatory cytokines. These mediators vary not only between diseases but also among affected populations, and their knowledge is important for the correct diagnosis and targeting of the therapy chosen. Objectives: To map the inflammatory mediators present in the nasal wash and the exhaled breath condensate in the CRS and AR, evaluating possible biomarkers of this diseases, and to analyze the inflammatory endotype of the patients studied. In addition, assess quality of life, level of nasal obstruction, sleep quality of affected patients, mucociliary transport and collect samples for pH analysis, total cell count and its differential. Patients and Methods: Prospective cross-sectional exploratory study, divided into four groups: 1) Control group with patients without complaints 2) Patients with AR with prick test positive 3) Patients with CRS with polyps 4) Patients with CRS without polyps. All patients responded to four questionnaires: 20-Item Sino-Nasal Outcome Test (SNOT-20p), Nasal Obstruction Symptom Evaluation (NOSE), Pittsburgh Sleep Quality Index (PSQI-BR) and European Community Respiratory Health Survey (ECRHS) questionnaire for screening and diagnosis of asthma. A physical examination was performed, including nasal endoscopy (modified Lund-Kennedy score) and, in patients with CRS, a computerized tomography (Lund-Mackay score) evaluation. The mucociliary transport was also evaluated through the saccharin test. The exhaled breath condensate was collected for pH analysis and the nasal wash for evaluation of pH, cytokines and cellularity (total and differential). The presence of IL-4, IL-5, IL-17, IL-17A, IL-22, TNF-Alfa and IFN-Gama in the nasal wash and IL-5, IL-17A, IL-22 and IFN-Gama in the exhaled breath condensate. Results: Patients with CRS had significantly worse scores in the nasal obstruction questionnaire (NOSE, p < 0.01) and quality of life questionnaire (SNOT-20p, p < 0.01) when compared to controls, and both patients with CRS and AR presented worse sleep quality (PSQI-BR, p < 0.01). The Lund-Mackay extension score was higher in patients with CRS with polyps (p < 0.02). The saccharin test showed longer time in the CSR group with polyps (p < 0.01). The pH of the exhaled breath condensate did not differ between groups. The CRS with polyps group presented both pH difference (p < 0.01) and higher total nasal wash cell count (p < 0.01) when compared to the control group, but with no difference in the differential count (p = 0.05), while IL-5 was higher in the CRS group with polyps when compared to the RSC without polyps group (p = 0.02). Patients were then divided into endotypes according to the groups described by Tomassen et al, Endotypes are the subtypes of the disease defined functionally and pathologically by distinct molecular mechanisms. Conclusions: Patients with CRS presented worse scores on quality of life questionnaires (SNOT-20p and NOSE), which could be attributed in part to the poorer quality of sleep presented by both patients with CRS and AR. The saccharin test evidenced worse mucociliary transport in patients with CRS with polyps when compared with control group. There was no difference in the pH of the exhaled breath condensate, suggesting that, although interesting in the evaluation of the lower airways, this may not be a good test for analyzing the upper airways. Significant alterations were found in both pH and total nasal wash cell count in the CSR group with polyposis, but there was no difference in the differential count. Of the 17 patients with CRS with complete cytokine profile, 12 fit into already described endotypes, and of the remaining five, two have the same profile, which may indicate a new subgroup

Le système immunitaire se doit d’être étroitement régulé afin d’éviter que des réponses immunologiques inappropriées ou de trop forte intensité ne surviennent. Ainsi, différents mécanismes permettent de maintenir une tolérance périphérique, mais aussi d’atténuer la réponse lorsque celle-ci n’est plus nécessaire. De tels mécanismes sont cependant aussi exploités par les tumeurs, qui peuvent ainsi échapper à une attaque par le système immunitaire et donc poursuivre leur progression. Ces mécanismes immunosuppresseurs nuisent non seulement à la réponse naturelle contre les cellules tumorales, mais font aussi obstacle aux tentatives de manipulation clinique de l’immunité visant à générer une réponse anti-tumorale par l’immunothérapie. L’un des mécanismes par lesquels les tumeurs s’évadent du système immunitaire est l’expression d’enzymes responsables du métabolisme des acides aminés dont l’une des principales est l’indoleamine 2,3-dioxygénase (IDO). Cette dernière dégrade le tryptophane et diminue ainsi sa disponibilité dans le microenvironnement tumoral, ce qui engendre des effets négatifs sur la prolifération, les fonctions et la survie des lymphocytes T qui y sont présents. Bien que la régulation de l’expression de cette enzyme ait été largement étudiée chez certaines cellules présentatrices d’antigènes, dont les macrophages et les cellules dendritiques, peu est encore connu sur sa régulation dans les cellules tumorales humaines. Nous avons posé l’hypothèse que différents facteurs produits par les cellules immunitaires infiltrant les tumeurs (TIIC) régulent l’expression de l’IDO dans les cellules tumorales. Nous avons effectivement démontré qu’une expression de l’IDO est induite chez les cellules tumorales humaines, suite à une interaction avec des TIIC. Cette induction indépendante du contact cellulaire résulte principalement de l’interféron-gamma (IFN-g) produit par les lymphocytes T activés, mais est régulée à la baisse par l’interleukine (IL)-13. De plus, la fludarabine utilisée comme agent chimiothérapeutique inhibe l’induction de l’IDO chez les cellules tumorales en réponse aux lymphocytes T activés. Cette observation pourrait avoir des conséquences importantes en clinique sachant qu’une forte proportion d’échantillons cliniques provenant de tumeurs humaines exprime l’IDO. Enfin, les lymphocytes B, qui sont retrouvés également dans certaines tumeurs et qui interagissent étroitement avec les lymphocytes T, sont aussi susceptibles à une induction transcriptionnelle et traductionnelle de l’IDO. Cette enzyme est cependant produite sous une forme inactive dans les lymphocytes B, ce qui rend peu probable l’utilisation de l’IDO par les lymphocytes B comme mécanisme pour freiner la réponse immunitaire. Nos travaux apportent des informations importantes quant à la régulation de l’expression de la molécule immunosuppressive IDO dans les cellules cancéreuses. Ils démontrent que l’expression de l’IDO est influencée par la nature des cytokines présentes dans le microenvironnement tumoral. De plus son expression est inhibée par la fludarabine, un agent utilisé pour le traitement de certains cancers. Ces données devraient être prises en considération dans la planification de futurs essais immunothérapeutiques, et pourraient avoir un impact sur les réponses cliniques anti-tumorales. / The immune system is under tight control to avoid inappropriate and excessive immunological responses. Many mechanisms allow the maintenance of peripheral tolerance and mediate attenuation of the immune response after pathogen clearance. Such mechanisms are also exploited by tumors, thereby favoring their escape from assault by the immune system. These immunosuppressive mechanisms hamper host natural immune responses against tumor cells, but also represent an obstacle to the successful clinical manipulation of the immune system in attempts to generate an anti-tumor response through immunotherapy. One immune escape mechanism used by tumors is the production of enzymes responsible for amino acid metabolism, amongst which indoleamine 2,3-dioxygenase (IDO) is of major importance. IDO degrades tryptophan, thus leading to its depletion from intracellular pools and local microenvironments. This culminates in multi-pronged negative effects on T lymphocytes neighboring IDO-expressing cells, notably on proliferation, function and survival. The regulation of IDO expression has been largely studied in antigen-presenting cells such as macrophages and dendritic cells, but its regulation in human tumor cells must still be characterized. We hypothesized that different factors produced by tumor-infiltrating immune cells (TIIC) regulate IDO expression in tumor cells. Accordingly, we have demonstrated that IDO expression is induced in human tumor cells upon interaction with TIIC. This induction is cell contact-independent, and results mainly from interferon-gamma (IFN-g) produced by activated T lymphocytes, while being antagonised by interleukin (IL)-13. Moreover, the chemotherapeutic agent fludarabine inhibits activated T lymphocyte-dependent IDO induction in tumor cells. This observation could have major clinical consequences, considering the large proportion of human cancer clinical samples expressing IDO. Finally, B lymphocytes, which interact closely with T lymphocytes and are found infiltrating human tumors, are also susceptible to transcriptional and translational IDO induction. This enzyme is however produced in an inactive form, suggesting that B lymphocytes do not exploit this mechanism to impede the immune response. In conclusion, our work brings crucial information on the regulation of the immunosuppressive molecule IDO in human tumor cells. We demonstrate that IDO expression is dependent on the nature of cytokines present in the tumor microenvironment. Furthermore, its expression is inhibited by fludarabine, a compound used to treat some types of cancer. These data should be taken into consideration in planning future immunotherapy trials and could impact anti-tumor clinical responses.

La barrière hémo-encéphalique (BHE) est formée des cellules endothéliales microvasculaires cérébrales reliées entre elles par des jonctions serrées. Grâce à sa perméabilité restreinte et sélective, la BHE entrave le passage des molécules et cellules du sang vers le système nerveux central (SNC). Chez les patients atteints de sclérose en plaques (SEP), une maladie inflammatoire du SNC, la rupture de la BHE permet aux cellules immunes actives d'infiltrer le tissu cérébral. Il s'ensuit une réaction inflammatoire excessive au cours de laquelle d'autres leucocytes sont recrutés dans le cerveau et qui culmine par la formation des plaques de démyélinisation caractéristiques de la SEP. On dénote au niveau de ces lésions une présence importante de lymphocytes T CD4⁺ activés et de cytokines pro-inflammatoires propres à une réponse de type TH1, tels l’IFN-γ et l’IL-1. Curieusement cependant, l’inhibition de la voie TH1 n’empêche pas l’apparition de la maladie dans le modèle murin de la SEP et en aggrave même les symptômes. On attribue maintenant aux lymphocytes TH17, nommées en raison de leur capacité à produire de l’IL-17, un rôle clé dans le développement de la maladie. L’objectif de ce travail de thèse visait à caractériser les lymphocytes TH17 chez l’humain et définir leur contribution exacte dans la fragilisation de la BHE, une étape décisive dans la formation des lésions de SEP. Pour ce faire, nous avons mis au point une méthode expérimentale permettant l’expansion in vitro de populations de lymphocytes TH17 à partir de cellules mononuclées du sang de donneurs sains. Nos travaux démontrent que l’IL-23 induit la production d’IL-17, d’IL-22 et de granzyme B par les lymphocytes T CD4⁺CD45RO⁺ mémoires humains et qu’une proportion des cellules exprime de manière concomitante de l’IL-17 et de l’IFN-γ. La fréquence des lymphocytes T CD4⁺ IL17⁺, IL-22⁺ et des doubles positifs IL-17⁺IFN-γ⁺ est significativement plus élevée dans les lignées de lymphocytes TH17 provenant de patientes en poussée que dans celles de contrôles. Nos analyses démontrent que les cellules endothéliales de la BHE expriment de faibles niveaux des récepteurs de l’IL-17 et de l’IL-22 à l’état basal mais que leur présence est accrue dans le cerveau de patients atteints de SEP. L’activation du récepteur de l’IL-17 entraîne une augmentation de la perméabilité de la BHE et une perturbation de l’organisation des protéines de jonction occludine et ZO-1. Finalement, nous démontrons que la migration des lymphocytes TH17 à travers la BHE est régie en grande partie par la molécule d’adhérence ICAM-1 et que les lymphocytes qui co-expriment l’IL-17 et l’IFN-γ sont plus aptes à franchir la BHE que ceux qui produisent uniquement l’une ou l’autre de ces cytokines. Nous retrouvons d’ailleurs des cellules qui expriment simultanément les facteurs de transcription T-bet et RORC, associés respectivement aux lymphocytes TH1 et aux TH17, au sein des infiltrats péri-vasculaires des lésions actives de SEP. Les travaux présentés dans cette thèse auront permis d’affiner nos connaissances sur les mécanismes d’entrée des lymphocytes TH17 dans le SNC et les propriétés délétères des cytokines qu’ils sécrètent, notamment dans l’activation et la déstabilisation de l’endothélium cérébral. / The blood-brain barrier (BBB) plays a crucial role in protecting the central nervous system (CNS) by restricting entry of cells and molecules into the brain. In the CNS disorder multiple sclerosis (MS), breakdown of the BBB allows activated leukocytes to infiltrate the brain parenchyma, leading to the formation of the characteristic demyelinated lesions. For decades, MS was viewed as a TH1-mediated disease, a notion that was largely supported by studies in its animal model and by the abundance of prototypical TH1-associated cytokines within active MS lesions. However, over the years, accumulating evidence has highlighted the involvement of another subset of CD4⁺ T cells that express IL-17, therefore named TH17 lymphocytes, in the pathology of the disease. The goal of the work presented herein was to characterize the human TH17 lymphocyte population and define their contribution to the disruption of the BBB and leukocyte infiltration into the CNS, both important early events in the formation of MS lesions. To do so, we developed and optimized a method to successfully generate human TH17 lines in vitro from peripheral blood mononuclear cells of healthy donors. We demonstrate that in response to IL-23, human memory CD4⁺CD45RO⁺ but not naïve CD4⁺CD45RA⁺ T lymphocytes produce IL-17, IL-22, and granzyme B, with a subset of cells simultaneously expressing IL-17 and IFN-γ. Interestingly, we measure a significant increase in the percentage of T CD4⁺ IL17⁺, of IL-22⁺, and of IL-17⁺IFN-γ⁺ dual producers in TH17 cell lines expanded from the peripheral blood of acutely relapsing MS women as compared to those generated from healthy controls and remitting MS patients. We show that both IL-17 and IL-22 receptors are upregulated on BBB endothelial cells in situ during inflammation and that IL-17 enhances BBB permeability by disrupting the integrity of tight junction proteins occludin and ZO-1. Finally, we provide evidence that TH17 lymphocytes transmigrate efficiently across human brain endothelial cells via the adhesion molecule ICAM-1 and show that IL-17⁺IFN-γ⁺ double producers have an increased propensity to do so. Accordingly, we detect lymphocytes that display immunoreactivity against both the TH1- and TH17-associated transcription factors T-bet and RORC within perivascular infiltrates of active MS lesions. The work presented in this thesis has refined our understanding of the mechanisms that drive TH17 lymphocyte recruitment into the CNS and shed light on the deleterious effect of TH17-secreted cytokines, specifically in the activation and breakdown of the BBB.

Glycosphingolipids (GSLs), composed of a polar saccharide head and a lipophilic ceramide tail, are ubiquitous components of the plasma membrane of eukaryotic cells. They serve in many regulatory capacities and have antigenic properties towards natural killer T (NKT) cells of the innate immune system. Critical to the recognition of glycosylceramides by NKT cells are antigen presenting cells (APC), such as dendritic cells, which are responsible for binding, processing, and delivery of ligands to these lymphocytes. This event is mediated by CD1d, a major histocompatibility complex-like protein expressed on the surface of APCs, which binds GSL antigens by the ceramide moiety and presents the polar group to the T cell receptors of CD1d-restricted cells. The subsequent immune response involves NKT cell proliferation and emission of numerous cytokines, such as interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), resulting in the stimulation of the innate and adaptive immune systems through maturation of APCs, activation of T cells, and secretion of antibodies by B cells. To understand the structure-activity relationship between GSLs and NKT cell activity and the requirements for intracellular processing of antigens, analogs of the model compound alphaGalCer (KRN-7000) have been synthesized. These include fluorophore-appended 6”-amino-α-galactosylceramides and N-alkenoyl GSLs, such as PBS-57, a potent alphaGalCer surrogate useful in NKT cell stimulation studies. A nonantigenic beta-C-galactosylceramide has also been prepared as an inhibitor of these innate lymphocytes. To probe the potential for using NKT cells to bias the immune system between the proinflammatory TH1 response or the immunomodulatory TH2 mode, versions of alphaGalCer with shortened ceramides have been created. One of these truncated analogs, PBS-25, has successfully been cocrystallized with CD1d and the binary complex structure solved by X-ray crystallography. Synthetic glycosphingolipids derived from Novosphingobium capsulatum and Sphingomonas paucimobilis have also been made. In assays with classical Valpha14i/Valpha24i NKT cell lines, these Gram-negative bacterial antigens were recognized directly and specifically by host immune systems through CD1d-restriction, unlike GSL-deficient microbes (e.g., Salmonella typhimurium). A search for other GSL-bearing alpha-proteobacteria led to the discovery of another natural glycosphingolipid, an N-alkenoylphytosphingoid-alpha-galactoside, isolated from the outer membrane of Ehrlichia muris.

Modifying the metabolism of the body’s own endocannabinoids is a novel approach for analgesia. Two key catabolic enzymes are fatty acid amide hydrolase (FAAH) and inflammation-inducible cyclooxygenase 2 (COX-2). The cellular uptake of the key endocannabinoid anandamide (AEA) has been found to be regulated by its FAAH-catalysed intracellular degradation, but COX-2 has not been investigated in this respect. We aimed to find out whether or not COX-2 in an in vitro inflammation setting would be able to gate AEA uptake. To achieve this, C6 cells and Raw 264.7 cells were stimulated with LPS/INF-γ and lysates then analyzed by immunoblot in order to verify COX-2 expression. AEA cellular uptake was quantified using a radioassay with [3H]-AEA. It was found that COX-2 was not inducible in C6 cells using the LPS/INF-γ conditions studied, while it was inducible in Raw 264.7 cells. AEA uptake in the COX-2-induced Raw 264.7 cells was not reduced by inhibitors of this enzyme. FAAH appeared to be down-regulated in the stimulated Raw 264.7 cells, and this was reflected in an overall lower AEA uptake. Our interpretation of the data points to FAAH as gating AEA uptake. Additional experiments are required to validate our findings by verifying significance.