A doença renal crônica (DRC) é a afecção renal mais frequente em cães e caracteriza-se pela progressiva redução do número de néfrons funcionais. Com a evolução da doença, os cães podem apresentar um conjunto de manifestações clínicas denominada uremia. O suporte nutricional objetiva atenuar os efeitos do estado urêmico, retardar a progressão da doença e melhorar a qualidade de vida dos animais. O presente estudo objetivou avaliar os efeitos da dieta coadjuvante e manejo dietético no metabolismo de cálcio e fósforo [fósforo, cálcio total (CaT), cálcio iônico (Cai), paratormônio (PTH) e FGF-23 séricos], escore de condição corporal (ECC), escore de massa muscular (EMM), concentrações séricas de aminoácidos (AAs) e citocinas inflamatórias (CIT), bem como a capacidade antioxidante total (CAT) de cães com DRC alimentados com dieta coadjuvante. Foram selecionados 10 cães com DRC estádios 3 e 4 (IRIS, 2015) provenientes do atendimento do Hospital Veterinário da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo. As variáveis PTH, FGF-23, AAs, CIT e CAT foram avaliadas no início do estudo (T0) e após 6 meses de manejo dietético (T6). As determinações séricas de ureia, creatinina, CaT, Cai e fósforo; ECC e EMM foram determinadas em T0 e a cada 30 dias, durante os 6 meses de estudo. Para a análise dos resultados, testes estatísticos paramétricos e não paramétricos foram empregados e valores de p&lt;0,05 foram considerados significativos. As concentrações séricas de ureia, fósforo, CaT, Cai, IL-6, IL-10, TNF-&#945;, CAT, PTH e FGF-23 não apresentaram diferença entre os momentos T0 e T6. A creatinina elevou-se em T6 (p=0,0022). Os AAs fenilalanina, triptofano e ornitina decresceram no tempo T6 (p=0,0273; p=0,0253; p=0,0443, respectivamente) e a hidroxiprolina aumentou em T6 (p=0,0073). As concentrações séricas de PTH apresentaram correlação com a creatinina e ureia (r=0,45, p&lt;0,05; r=0,67, p&lt;0,01; respectivamente). O Cai apresentou correlação negativa com a ureia (r=-0,59, p&lt;0,01) e o fósforo sérico apresentou correlação positiva com o FGF-23 (r=0,51; p&lt;0,05). A ureia e creatinina apresentaram correlação positiva (r=0,62; p&lt;0,01). De acordo com os resultados encontrados, conclui-se que a dieta e o manejo nutricional empregados foram eficazes no controle do hiperparatireoidismo secundário renal, estresse oxidativo, marcadores inflamatórios e na manutenção do escore de condição corporal, massa muscular e nutrição proteica dos cães avaliados. / Chronic kidney disease (CKD) is the most common kidney disease in dogs and characterized by progressive reduction in the number of functional nephrons. With the evolution of the disease the dogs may present a set of clinical manifestations denominated uremia. The efforts of nutritional support are to mitigate the effects of uremic state, slow the progression of the disease and improve the quality of life of the animals. The aim of this study was to evaluate the effects of prescription diet and dietary management on the metabolism of calcium and phosphorus [phosphorus, total calcium (CaT), ionized calcium (Cai), parathyroid hormone (PTH) and FGF-23 in the serum], body condition score (BCS), muscle mass score (MME), serum concentrations of amino acids (AAs) and inflammatory cytokines (CYT), as well as the total antioxidant capacity (TAC) of dogs with CKD fed with a coadjuvant diet. Were selected 10 dogs with CKD stage 3 and 4 (IRIS, 2015), from the Veterinary Hospital at School of Veterinary Medicine and Animal Science, University of São Paulo. The PTH, FGF-23, AAs, CYT and TAC variables were evaluated at baseline (T0) and after 6 months of dietary management (T6). The serum determinations of urea, creatinine, CaT, Cai and phosphorus; BCS and MMS were determined at T0 and every 30 days, for 6 months. For the analysis of the results, parametric and non-parametric statistical tests were used and values of p<0.05 were considered significant. Serum concentrations of urea, phosphorus, CaT, Cai, IL-6, IL-10, TNF-&#945;, CAT, PTH, FGF-23 did not differ between T0 and T6. Serum creatinine increased in T6 (p=0.0022). The AAs phenylalanine, tryptophan and ornithine decreased in T6 (p=0.0273; p=0.0253; p=0.0443, respectively) and hydroxyproline increased in T6 (p=0.0073). Serum PTH concentrations correlate positively with the concentrations of creatinine and urea (r=0.45, p&lt;0.05; r=0.67, p&lt;0.01; respectively). The Cai was negatively correlated with urea (r = -0.59, p&lt;0.01) and serum phosphorus was positively correlated with FGF-23 (r = 0.51; p&lt;0.05). The urea and creatinine were positively correlated (r=0.62; p&lt;0.01). It was concluded that diet and nutritional management were effective in the control of renal secondary hyperparathyroidism, oxidative stress, inflammatory markers and maintenance of body condition score, muscle mass and protein nutrition in the evaluated dogs.

A leishmaniose tegumentar americana (LTA) apresenta um amplo espectro de manifestações clínicas e imunopatológicas resultante da interação entre as diferentes espécies de Leishmania e os mecanismos de resposta imune do hospedeiro. Leishmania (Viannia) braziliensis e Leishmania (Leishmania) amazonensis são as espécies de maior potencial patogênico para o homem e de importância médica no Brasil. As células TCD4, quando ativadas por antígenos via MHC II podem se diferenciar em linhagens de células efetoras como Th1, Th2, Th17 e células T reguladoras (Treg). IL-23 é indispensável para as funções efetoras e manutenção de células Th17. O objetivo deste trabalho foi avaliar a expressão de Foxp3, IL-17 e IL-23 em lesões cutâneas de pacientes com diferentes formas clínicas da LTA. Biópsias parafinadas de 44 pacientes foram submetidas à imunoistoquímica, sendo 6 casos de leishmaniose cutânea anérgica difusa (LCADIDRM-) e leishmaniose cutânea disseminada borderline (LCDBIDRM-), ambas causadas por L.(L) amazonensis e 16 casos de leishmaniose cutânea localizada (LCLIDRM+) também causada por L.(L.) amazonensis; 9 casos de LCLIDRM+, 2 casos de LCDBIDRM- e 5 casos de leishmaniose cutâneo-mucosa (LCMIDRM+), todos causados por L.(V.) braziliensis. A densidade de células Tregs Foxp3+ no espectro clínico da LTA mostrou um aumento progressivo partindo das formas centrais LCL causadas por L.(V.) braziliensis (170mm2) e L.(L) amazonensis (140mm2) para as formas polares, LCADIDRM- (289mm2) e LCDBIDRM- (183mm2) causada por L.(L) amazonensis, LCDBIDRM- (189mm2) e LCMIDRM+, causadas por L.(V.) braziliensis (158mm2). A comparação entre as densidades de células IL-17+ nas diferentes formas clínicas da LTA mostrou um perfil semelhante também com um aumento progressivo da expressão de IL-17 partindo das formas centrais LCLIDRM+ causadas por L.(V.) braziliensis (232mm2) e L.(L) amazonensis (197mm2) em direção as formas polares, LCADIDRM- (470mm2) e LCDBIDRM- (340mm2) causada por L.(L.) amazonensis, LCDBIDRM- (431mm2) e LCMIDRM+ (372mm2) causada por L.(V.) braziliensis. A densidade de células IL-23+ mostrou perfil similar ao de IL-17 como no espectro de doença causada por L. (V.) braziliensis ou L. (L.) amazonensis: LCADIDRM- (687mm2), LCDBIDRM- (518mm2) e LCLIDRM+ (348mm2) por L.(L.) amazonensis, LCLIDRM+ (457mm2), LCDBIDRM- (609mm2) e LCMIDRM+ (568mm2) L. (V.) braziliensis. Diante dos nossos achados, observa-se que as células Foxp3+, IL-17+ e IL-23+ desempenham um papel importante na imunopatogênese das diferentes formas clínicas da LTA causadas por L. (V.) braziliensis ou L. (L.) amazonensis, caracterizada por uma resposta imune polarizada de diferente expressão patológica / The American cutaneous leishmaniasis (ACL) presents a wide spectrum of clinical and immunopathological manifestations resulting from the interaction between the different species of Leishmania and the mechanisms of the host immune response. Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis are the species with the largest pathogenic potential for humans and medical importance in Brazil. The CD4+ T cells can be differentiated into effector cell lines as Th1, Th2, Th17 and regulatory T cells (Treg). IL-23 is essential for effector functions and maintenance of Th17 cells, that produces IL-17. The aim of this study was to evaluate the expression of Foxp3, IL-17 and IL-23 in cutaneous lesions of patients with different clinical forms of ACL. Paraffin embedded biopsies from 44 patients were submitted to immunohistochemistry, there were 6 cases of anergic diffuse cutaneous leishmaniasis (ADCLDTH-) and borderline disseminated cutaneous leishmaniasis (BDCLDTH-) both caused by L. (L.) amazonensis 16 cases of cutaneous leishmaniasis (LCLDTH+) caused by L. (L.) amazonensis, 9 cases of LCLDTH+, 2 cases of BDCLDTH- and 5 cases of mucocutaneous leishmaniasis (MCLDTH+) all caused by L. (V.) braziliensis. The density of Treg Foxp3+ cells in the clinical spectrum of ACL showed a progressive increase starting from the central forms LCLDTH+ caused by L. (V.) braziliensis (170mm2) and L. (L) amazonensis (140mm2) towards the polar forms ADCLDTH- (289mm2). The intermediate clinical forms BDCLDTH- (183mm2) caused by L. (L) amazonensis and BDCLDTH-(189mm2) by L. (V.) braziliensis as well as, MCLDTH+(158mm2) did not present any significant differences. The comparison between the densities of IL-17+ cells in different clinical forms of ACL showed progressive increasing starting from the central forms LCLDTH+ caused by L. (V.) braziliensis (232mm2) and L. (L) amazonensis (197mm2) towards the polar forms, ADCLDTH-(470mm2) and BDCLDTH-(340mm2) caused by L. (L.) amazonensis BDCLDTH- (431mm2) and MCLDTH+ (372mm2) caused by L. (V.) braziliensis. The density of IL-23+ cells showed a similar profile to that of IL-17 at the disease spectrum caused by L. (V.) braziliensis and L. (L.) amazonensis: ADCLDTH-(687mm2) BDCLDTH-(518mm2) and LCLDTH+ (348mm2) by L. (L.) amazonensis; LCLDTH+ (457mm2) LCDBDTH-(609mm2) and MCLDTH+ (568mm2) L. (V.) braziliensis. In view of our findings, we notice that the Foxp3+, IL-17+ and IL-23+ cells play an important role in the immunopathogenesis of different clinical forms of ACL caused by L. (V.) braziliensis and L. (L.) amazonensis, characterized by an immune polarized response with different pathological expression

Introdução: Doador de rim em vida é uma importante fonte de órgão para os pacientes portadores de doença renal crônica (DRC). Os doadores experimentam uma redução abrupta da taxa de filtração glomerular (TFG) e adaptações ao metabolismo mineral demandam estudos nesta população. Nós avaliamos prospectivamente esta adaptação em doadores de rim em vida. Métodos: Entre janeiro de 2010 a agosto de 2011, no hospital das Clínicas de São Paulo e na Universidade de Miami, realizamos a avaliação prospectiva do metabolismo mineral e da função renal por 1 ano em 74 doadores de rim em vida. Medimos a taxa de filtração glomerular (TFG), fósforo (Pi), cálcio (Ca), paratohormônio (PTH), fibroblast Growth Factor 23 (FGF23) e a fração de excreção do fósforo (FePO4) no pré-operatório e nos dias 1, 2, 14, 180 e 360 do pós-operatório. Resultados: Observamos uma redução, aproximadamente, de 40% da TFG nos dois primeiros dias após a cirurgia. No décimo quarto dia após a nefrectomia, observamos o início da recuperação da TFG, chegando ao máximo da recuperação com 1 ano, quando se atingiu 68,6% da função renal se comparado com o dia anterior a doação (75,3 ml/min/1,73m2, p < 0,001). O cálcio sérico apresentou seu nadir no dia 1 (7,99 mg/dL; p < 0,01) e o Pi sérico atingiu seu nadir no dia 2 (2,61 mg/dL; p < 0,01). Já no dia 14, os valores de Ca e Pi retornaram aos valores basais tendo o fósforo evoluído novamente com valores inferiores ao basal no último dia de seguimento (3,36mg/dL; p < 0,001). FGF23 e PTH apresentaram elevação no D1 (111,0144,6 percentil 25-75: 16-63 RU/ml 64,9 30,3pg/mL; p < 0,01). Os valores de FGF23 se mantiveram elevados até o final do estudo enquanto que o PTH retornou aos valores de base no segundo dia e, a partir de então, manteve sem diferença do valores basais até o último dia de estudo. FePO4 elevou de 11,45,2% para 15,28,1% entre o pré-operatório e D365 (p < 0,01). Conclusão: A nefrectomia para doação de rim em 74 pacientes saudáveis elevou os valores de FGF23 durante todo o estudo juntamente com a FePO4. O fósforo, cálcio e PTH séricos apresentaram queda nos seus valores na primeira semana após a nefrectomia, e, com duas semanas após a cirurgia, retornaram aos valores basais mantendo-se estáveis até o final do estudo / Introduction: Living kidney donors (LKDs) experience an abrupt decline in glomerular filtration rate (GFR). Mineral metabolism adaptations in early CKD are still debated and not well studied in LKDs. We prospectively studied acute and long term mineral metabolism adaptation of LKDs. Materials and Methods: We measured renal function and mineral metabolites longitudinally for 1 year (days (D) 1, 2, 14, 180, & 365 post-operatively) in 74 healthy individuals who underwent kidney live donation. Results: eGFR (MDRD) decreased to 59% of its baseline on day 2 and started to increase at day 3, to its maximum at day 360 (75.3±15.6 ml/min/1.73m2, p < 0.01) wile FGF23 increased from 60.6 (25th-75th percentile 19-81 RU/mL) at baseline to 111.0±144.6 (p < 0.01) on day 1 and keep higher than baseline throwout the study. PTH rose maximally on day 1 (64.9 ± 30.3pg/ml) and returned to its base line on D2 and did not change after that. Total serum Calcium levels decreased from 9,40±0,48 mg/dL to a nadir of 7.99±0,51 mg/dL on day 1 (p < 0.001). Serum Phosphate levels reached their nadir on day 2 (2.61±0,52 mg/dL; p < 0.01). At D14 total calcium and phosphate levels had returned to baseline, but phosphate levels returned down on D360 (3.36±0,52 mg/dL; p < 0.001). Phosphate excretion fraction (FePO4) increased from base line (11.4±5.2%) up to 15.2±8.1% until D360 (p < 0.001). Conclusions: Abrupt reduction in eGFR induces physiological increases in FGF23 and PTH, and decreases in serum Ca and Pi in the first week. The changes in FGF23 and Pi urinary fractional excretion of Pi remain modestly yet significantly different from baseline throughout the first year after nephrectomy. Wile Ca, PTH and Pi serum levels are not significantly different from the baseline

L’arsenic inorganique est un contaminant environnemental, cancérogène pour l’homme, mais également un métalloïde étudié, aujourd’hui, dans le traitement de maladies inflammatoires chroniques. Il possède des propriétés immunosuppressives pouvant déréguler les mécanismes physiologiques de défense ou bloquer l’exacerbation de réponses inflammatoires chroniques. L’arsenic inorganique altère principalement les fonctions des lymphocytes T et des macrophages. En revanche, l’impact du métalloïde sur la physiologie des cellules dendritiques (DCs) est peu connu. Pourtant, ces cellules présentatrices d’antigène jouent un rôle fondamental dans les processus d’immunosurveillance et sont très impliquées dans la physiopathologie des maladies inflammatoires chroniques. Dans ce contexte, les objectifs de mon travail de thèse étaient d’étudier les effets de l’arsenic inorganique sur la différenciation et la maturation in vitro de DCs générées à partir de monocytes humains. Nos résultats démontrent principalement que des concentrations de métalloïde, compatibles avec les taux plasmatiques d’arsenic mesurés chez les individus exposés, répriment la capacité des DCs à sécréter différentes cytokines pro-inflammatoires jouant un rôle essentiel dans l’activation et la polarisation des lymphocytes T. En particulier, l’arsenic inhibe l’expression et la sécrétion de l’interleukine-12 par un mécanisme moléculaire impliquant le facteur de transcription Nrf2. Au total, ces travaux de thèse démontrent que l’arsenic inorganique possède des propriétés immunosuppressives sur la physiologie in vitro des DCs humaines. Cette immunotoxicité pourrait contribuer à la toxicité du métalloïde chez l’homme exposé par voie environnementale, et être prise en compte pour déterminer les effets de l’arsenic dans le traitement de certaines maladies inflammatoires chroniques / Inorganic arsenic is an environmental human carcinogen, but is also studied these days because of its potential effectiveness in curing chronic inflammatory disease. Indeed, this metalloid possesses immunosuppressive properties which can dysregulate physiological mechanisms involved in immune defense, or reduce inflammation associated with those inflammatory diseases. Inorganic arsenic is known mainly to alter functions of T cells and macrophages. However, it is unknown whether arsenic targets dendritic cells (DCs). Yet, this antigen presenting cells plays a major role in the immunosurveillance, and is involved in the physiopathology of chronic inflammatory diseases. So, the aim of my thesis work was to study the effects of inorganic arsenic on in vitro differenciation and maturation of dendritic cells from human monocytes. Our results mainly shows that concentrations corresponding to those measured in environmentally exposed people, inhibits DCs secretion of proinflammatory cytokines, which plays a major role in activation and polarization of T cells. Particularly, arsenic strongly impairs expression and secretion of interleukine 12 (IL-12) by an underlying molecular mechanism involving Nrf2. Finally, this work shows that inorganic arsenic has immunosuppressive properties on the physiology in vitro of human dendritic cells. Immunotoxicity may then contribute to the metalloid toxicity in environmentally exposed people. This element could be taken into account when determining arsenic effects in curing some chronic inflammatory diseases.

L'éminence ganglionnaire médiale (MGE) produit la grande majorité des interneurones GABAergiques corticaux synthétisant la parvalbumine. Les neuroblastes issus de la MGE migrent sur une longue distance avant d'atteindre leur destination finale. A ce jour, on ne sait pas s'il existe des mécanismes moléculaires les guidant vers des régions corticales données. Je montre que deux protéines apparentées aux cadhérines, cdhr23 et cdhr15, ont un rôle déterminant dans le développement d'interneurones du cortex auditif et de manière spécifique. Chez la souris et le macaque, ces deux protéines sont co-synthétisées par des neuroblastes issus de la MGE pendant leur migration. Chez les souris déficientes pour Cdhr23 ou Cdhr15, les neuroblastes synthétisant cdhr15 ou cdhr23 s'accumulent dans le télencéphale basal, ne parviennent pas à pénétrer dans le néocortex et présentent in vitro des défauts de polarité cellulaire. Cdhr15 intervient dans la survie des précurseurs d'interneurones à parvalbumine pendant la première semaine postnatale. Les souris mutantes pour Cdhr23 ou Cdhr15 présentent à trois semaines un nombre réduit d'interneurones à parvalbumine dans leur cortex auditif mais pas dans les cortex avoisinants. Cette diminution est associée à une disposition aux crises audiogènes. Mes résultats indiquent que des précurseurs d'interneurones du cortex auditif sont équipés de protéines d'adhérence déterminantes pour leur migration et leur intégration dans le cortex auditif. Ils suggèrent l'existence d'un possible mécanisme moléculaire général fondé sur un " code d'adhérence " qui déterminerait les neuroblastes GABAergiques dès leur naissance à intégrer une aire corticale donnée. / The medial ganglionic eminence (MGE) gives rise to the majority of cortical GABAergic interneurons that synthetize parvalbumin. Neuroblasts born in the MGE undergo a long distance migration before reaching their final target. Up to now, it is unknown whether any molecular mechanism guides them to specific cortical regions. I show that two cadherin-related proteins, cdhr23 and cdhr15, have a critical role in the development of interneurons of the auditory cortex, specifically. In mice and macaque, the two proteins are co-synthetized in neuroblasts from the MGE during their migration. In mouse mutants for Cdhr23 or Cdhr15, neuroblasts synthetizing cdhr15 or cdhr23 accumulate in the basal telencephalon, fail to enter the neocortex and present in vitro cell polarity defects. Cdhr15 is involved in the survival of parvalbumin interneuron precursors during the first postnatal week. Mutant mice for Cdhr23 and Cdhr15 show at three weeks a reduced number of parvalbumin interneurons in the mouse auditory cortex but not the neighbouring ones. This decrease is associated with a susceptibility to audiogenic seizures. My results reveal that interneuron precursors of the auditory cortex are endowed by specific adhesion proteins critically involved in their migration and integration in the auditory cortex. They suggest a possible general molecular mechanism based on an "adhesion code” that would determine GABAergic neuroblasts from their birth to a specific cortical region.

Platelets affect vascular integrity by secreting a host of molecules that promote hemostasis and its sequela. Given its importance, it is critical to understand how platelet exocytosis is controlled. Post-translational modifications, such as phosphorylation and acylation, have been shown to affect signaling pathways and platelet function. In this dissertation, I focus on how these modifications affect the t-SNARE proteins, SNAP-23 and syntaxin-11, which are both required for platelet secretion. SNAP-23 is regulated by phosphorylation. Using a proteoliposome fusion assay, I demonstrate that purified IκB Kinase (IKK) phosphorylated SNAP-23, which increased the initial rates of SNARE-mediated liposome fusion. SNAP-23 mutants containing phosphomimetics showed enhanced initial fusion rates. These results, combined with previous work in vivo, confirm that SNAP-23 phosphorylation is involved in regulating membrane fusion, and that IKK-mediated signaling contributes to platelet exocytosis. To address the role(s) of acylation, I sought to determine how syntaxin-11 and SNAP-23 are associated with plasma membrane. Using metabolic labeling, I showed that both proteins contain thioester-linked acyl groups which turn over in resting cells. Mass spectrometry mapping showed that syntaxin-11 is modified on C275, 279, 280, 282, 283 and 285, while SNAP-23 is modified on C79, 80, 83, 85, and 87. To probe the effects of acylation, I measured ADP/ATP release from platelets treated with the acyl-transferase inhibitor, cerulenin, or the thioesterase inhibitor, palmostatin B. Cerulenin pretreatment inhibited t-SNARE acylation and platelet function while palmostatin B had no effect. Interestingly, pretreatment with palmostatin B blocked the inhibitory effects of cerulenin suggesting that maintaining the acylation state of platelet proteins is important for their function. Thus my work indicates that the enzymes controlling protein acylation could be valuable targets for modulating platelet exocytosis in vivo.

No description available.

Les maladies inflammatoires de l'intestin (MII) sont caractérisées par des réponses immunitaires incontrôlées dans l'intestin. Des études génétiques ont associé un polymorphisme dans le gène de l'IL23R à la résistance aux MII. IL23R code pour la protéine de l’IL-23r, une sous-unité du récepteur à l’IL-23 (IL-23R). Ce récepteur appartient à la famille de l’IL-12R, contenant plusieurs récepteurs hétérodimériques. D’ailleurs, IL-12R et IL-23R partagent la sous-unité IL12Rb1. Néanmoins, ces deux récepteurs favorisent des réponses immunitaires distinctes (Th1 vs Th17). Ce mémoire caractérise les dynamiques d’expression cellulaires de l’IL-23R et l’IL-12R, afin d’élucider leurs rôles dans l’inflammation. Nous avons établi qu’IL-23R et IL-12R ne sont jamais co-exprimés, malgré qu’ils partagent la sous-unité IL-12Rβ1. Parmi les cellules de rates de souris, la protéine IL-23r est trouvée dans certaines cellules T TCRγδ ou T CD4+, quelques cellules B et des cellules Lti-like. La protéine IL-12Rβ2 est exprimée par quelques cellules B. L’analyse de l’expression de l’IL-23R et l’IL-12R dans différents organes révéla que la plus grande proportion de cellules exprimant l’IL-23R se retrouve dans la lamina propria de l'intestin grêle, alors que les cellules exprimant l’IL-12Rβ2 ont été retrouvées en proportion équivalente dans tous les organes lymphoïdes. Ces observations appuient les études génétiques suggérant un rôle prédominant de l’IL23R dans les intestins. Finalement, des cultures in vitro suggèrent que l’IL-23R ou l’IL-12R avaient des réactions croisées à l’IL-12 ou l’IL-23. L’étude de l’IL-23R dans les MII devrait donc être complémentée par l’étude de l’IL-12R, car les deux récepteurs pourraient avoir des rôles complémentaires. / Inflammatory bowel diseases (IBD) are characterised by uncontrolled immune responses in the gut. Genome-wide association studies (GWAS) have identified a protective polymorphism for IBD in the IL23R gene. IL23R codes for the IL-23r protein, one of the two subunits of IL-23R. IL-23R belongs to the IL-12R family, which contains many heterodimeric receptors. For example, both IL-12R and IL-23R share the IL-12Rβ1 subunit. Nevertheless, IL-12R and IL-23R are associated with different immune processes (Th1 vs. Th17). This thesis characterizes the cellular patterns of expression of both IL-23R and IL-12R, to further elucidate their roles in inflammation. We established that IL-23R and IL-12R were never co-expressed together, even though they share the IL-12Rβ2 subunit. Analysis of murine splenocytes revealed that IL-23R is expressed by some TCRγδ T-cells, a few B-cells, CD4+ T-cells and several Lti-like cells. IL-12R protein was found in a few B-cells. The analysis of IL-23R and IL-12R expression in different organs revealed that the lamina propria of the small intestine was the organ containing the largest proportion of IL-23r+ cells. IL-12R+ cells were found in constant numbers throughout the organs. Finally, in vitro cultures showed that IL-23R and IL-12R had crossed reaction to IL-12 and IL-23. Study of IL-23R in IBD should always be accompanied by IL-12R analysis, because both receptors could have complementary roles.

Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-05-30T17:13:22Z No. of bitstreams: 1 DIS_BELISA_AVILA_RODRIGUES_PARCIAL.pdf: 420085 bytes, checksum: 77f9b7ddcd1250899386df6d319c1934 (MD5) / Made available in DSpace on 2017-05-30T17:13:22Z (GMT). No. of bitstreams: 1 DIS_BELISA_AVILA_RODRIGUES_PARCIAL.pdf: 420085 bytes, checksum: 77f9b7ddcd1250899386df6d319c1934 (MD5) Previous issue date: 2016-07-29 / Acinetobacter calcoaceticus-baumannii (ACB) are opportunistic pathogens responsible for respiratory tract infections, wound infections, and bacteremia in intensive care units patients. These microorganisms became a problem in health care units due to their ability to acquire and accumulate resistance determinants. They are resistant to important antibiotics commonly used to treat infections caused by them. Thus, this study aimed to determine the antimicrobial susceptibility and detect resistance determinants in clinical ACB isolates. For this, 200 clinical ACB isolates, resistant to carbapenems, were collected from a hospital in Porto Alegre, Brazil. To determine susceptibility to antimicrobial agents, 16 antimicrobials were used in the disk diffusion technique and the minimum inhibitory concentration (MIC) for polymyxin B and meropenem was performed by broth microdilution. Additionally, MIC for polymyxin B in 17 isolates was determined using different methods in comparison with broth microdilution, adopted as reference method. The presence of blaOXA-23, blaOXA-51, blaIMP and blaNDM, as well as class 1 and 2 integrons, were detected by PCR. A total of 82.5% were extremely resistant (XDR) and 17.5% were multidrug resistant (MDR). Forty-six non-susceptibility patterns were found among the isolates, with polymyxins, tetracyclines, and aminoglycosides being the classes with higher rate of susceptibility. When different methods to determining MIC for polymyxin B were evaluated, very major errors and major errors were found in E-test and major errors in agar dilution, as compared with the reference method. The broth microdilution with polysorbate 80 showed a reduction of two or more dilutions in most isolates (82.3%). The blaOXA-23 and blaOXA-51 genes were found in 100% of the isolates, while 49% harbored blaIMP. The blaNDM gene was not found in any isolate. Class 1 and class 2 integrons were found in 68% and 88% of the isolates, respectively. The high percentage of XDR isolates, as well as the detection of important resistance determinants and the high rate of integrons found, reinforce the concern regarding ACB microorganisms and their spread in health care units. / Acinetobacter calcoaceticus-baumannii (ACB) s?o pat?genos oportunistas respons?veis por infec??es do trato respirat?rio, infec??es de feridas e bacteremia em pacientes internados em unidades de terapia intensiva. Esses microrganismos tornaram-se um problema nas unidades de assist?ncia ? sa?de devido ? sua capacidade de adquirir e acumular determinantes de resist?ncia a antimicrobianos, sendo respons?veis por altas taxas de resist?ncia aos principais antimicrobianos utilizados terapeuticamente. Desta forma, esse estudo teve por objetivo determinar a suscetibilidade a antimicrobianos, assim como detectar determinantes de resist?ncia em isolados cl?nicos de ACB. Para isso, foram utilizados 200 isolados cl?nicos, resistentes aos carbapen?micos, pertencentes ao complexo ACB, coletados de um hospital em Porto Alegre, Brasil, no per?odo de janeiro de 2012 a maio de 2015. Para determinar a suscetibilidade a antimicrobianos, 16 f?rmacos foram utilizados na t?cnica de disco-difus?o, assim como foi determinada a concentra??o inibit?ria m?nima (CIM) para polimixina B e meropenem por meio da t?cnica de microdilui??o em caldo. Adicionalmente, a CIM para polimixina B foi determinada em 17 isolados, empregando diferentes m?todos em compara??o com a microdilui??o em caldo, adotada como refer?ncia. Os genes blaOXA-23, blaOXA-51, blaIMP e blaNDM, bem como os integrons de classe 1 e 2 foram detectados por PCR. Um total de 82,5% dos isolados foram extremely resistant (XDR) e 17,5% foram multidrug resistant (MDR). Quarenta e seis padr?es de n?o-suscetibilidade foram encontrados entre os isolados, sendo que polimixinas, tetraciclinas e aminoglicos?deos foram as classes com maior taxa de suscetibilidade. Na determina??o de CIM para polimixina B com diferentes m?todos, very major errors e major errors foram encontrados em E-test, e major errors em dilui??o em ?gar, quando comparados com o m?todo de refer?ncia. A microdilui??o em caldo suplementado com polissorbato 80 mostrou redu??o de duas ou mais dilui??es na maioria dos isolados (82,3%). Os genes blaOXA-23 e blaOXA-51 foram encontrados em 100% dos isolados, enquanto 49% apresentaram blaIMP. O gene blaNDM n?o foi encontrado nos isolados analisados. Integrons de classe 1 foram encontrados em 68% dos isolados e integrons de classe 2 em 88%. O elevado percentual de isolados XDR, assim como a detec??o de importantes determinantes de resist?ncia e a alta taxa de integrons encontrada, refor?am a preocupa??o com microrganismos do complexo ACB e sua dissemina??o nas unidades de assist?ncia ? sa?de.

Shiga toxin-producing E. coli (STEC) are globally relevant bacterial pathogens responsible for epidemic outbreaks of hemorrhagic diarrhea with variable progression to potentially fatal systemic Shiga toxicosis. Predictive clinical biomarkers and targeted therapeutic interventions for systemic Shiga toxicosis in diagnosed STEC patients are not available, and the impact of Shiga toxin production on STEC colonization and survival remain unclear. Improved murine models of STEC infection are needed to address knowledge gaps surrounding the gastrointestinal effects of Shiga toxins, as previously published models utilize ablation of host defense responses or microbiota depletion to facilitate colonization and are poorly suited for study of the effects of Shiga toxins on host responses. Dextran sulfate sodium (DSS) colitis in rodents has been associated with outgrowths of commensal E. coli in the literature, suggesting that DSS colitis could open a gastrointestinal niche usable by pathogenic STEC. This DSS colitis-based approach successfully induced susceptibility to robust colonization by two clinical isolate STEC strains in standard C57BL/6 mice. Studies using a Shiga-like toxin 2 (STX2)-producing clinical isolate STEC strain and its paired isogenic STX2 deletion strain (STEC(ΔSTX2)) revealed that STX2 was associated with delayed gastrointestinal clearance of STEC and concurrent reduction in colonic interleukin 23 (IL-23) axis transcripts known to be critical for pathogen clearance in other gastrointestinal pathogen models. In vivo reductions in IL-23 axis transcripts in the DSS+STEC model were supported by decreased IL-23 protein secretion by human macrophage-like cells during Shiga intoxication in vitro. Increased morbidity during STX2-producing STEC infection was associated with renal injury consistent with murine systemic Shiga toxicosis characterized by elevations in renal transcripts of molecular injury markers and histologically apparent renal tubular injury in a subset of mice. The dissertation research establishes a novel model of DSS colitis-facilitated murine STEC infection that recapitulates progression to systemic Shiga toxicosis in a subset of infected mice and demonstrates a clear STEC survival benefit associated with STX2 production. Shiga toxin-induced suppression of IL-23 axis signaling is a novel finding facilitated by the DSS+STEC model, demonstrating its utility for future delineation of the impacts of Shiga toxins on gastrointestinal host responses to STEC.